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BUREAU OF GEOLOOYAND MINERAL TECHNOLOGY

Proceedings of the

21st Forum on the Geolof Industrial Minerals

Theme:Aggregates to Zeolites (AZ)

inArizona and the Southwest

BUREAU OF GEOLOGYAND MINERAL TECHNOLOGY

edited bytIo Wesley Peirce

Arizona Bureau of Geologyand Mineral Technology

Geological Survey Branch

Special Paper 41987

Proceedings of the

21st forum on the Geologyof Industrial Minerals

Theme:~ggregates to Zeolites (AZ)

inArizona and the Southwest

edited byIf. Wesley Peirce

//'

Special Paper 41987

Arizona Bureau of Geologyand Mineral Technology

Geological Survey Branch

Foreword

The 21st "corning-of age" meeting of the Fbrum on the Geolcgy ofIndustrial Minerals was held April 9 through 12, 1985 in Tucson,Arizona, under the sponsorship of the Geological survey Branch ofthe Bureau. Participants in this meeting, an official event of theUniversity of Arizona's centennial celebration, carne from 28states, canada, and Mexico. seventy-five percent of the attendeeswere non-Ari zonans.

The Forum was invited to Tucson to showcase the role of non­metallic minerals in the economic development of the sunbelt regionof Arizona and the Southwest. Twenty-three reports'were given and22 of these are represented in these Proceedings, 16 as papers and6 as abstracts only. All writing's were edited for general clarityand captions and bibliographies were standardized.

special thanks are extended to the Society of Economic Geolo­gist's Foundation, Inc., for a $500 grant to assist in publishingthe Proceedings; Union Carbide, National Gypsum, DJval COrporation,Sil-Flo Inc., GSA Resources Inc., and D.W. Jaquays CO., for assis­tance with field trips; to Olga Hernandez for a heroic word pro­cessing effort, Jon Shenk for manuscript trouble shooting, PeterCOrrao for cover graphics, to JOe Lavoie for publication assembly,and, of course, to all authors.

H. V\esley PeirceGeneral Chairman

iii

Contents

rbre~rd • • • • • • • • • • • • • • • . . . . . . . . . . . . iii

Papers

Mining and environmentalism - finding common goalsJames R. ilinn • • • • • • • • • • • • • • • • • 1

Geologic setting of industrial rocks and minerals in ArizonaStephen J. Reynolds and H. W8sley Peirce • • • • • • • •• 9

Industrial minerals and rocks of ArizonaH. W8sley Pe irce ••••••••••••••••••••• 17

Industrial minerals of NevadaKeith G. Papke • • • • • • • • • • • • • • • • • • • • 24

Industrial minerals of utahBryce T. Tripp • • • • • • • • • • • • • • 31

The geology of cement raw materials - Pacific SOuthwestS. A. Kupferman • • • • • • • • • • • • • • • • • • • 37

. . . . • . . • . 123

83

44

64

90

55

81

120

116

106

. . . .. . . . . . . . .

. . . . . .

Geologic-setting and operations overview, Ilicerne Valleylimestone mining district, Lucerne Valley, California

Ibward J. Brown. • • . . • • • • • • . • • • . • . . •

Natural lightweight aggregates of the SOuthwest[Ennis Bryan . . . . . . . . . . . . . . . .

Acquisition of Federally owned industrial mineralsTerry S. Maley •••• • • • • • • • • • •

Mining industrial minerals on Arizona State Trust LandsEtlward C. Spalding •••• • • • • • • • • • • • • •

Minerals and health: The asbestos problemMalcolIn R:>ss • • • • • • • • • • • • • • • • • • •

A comparison of selected zeolite deposits of Arizona,New Mexico, and Texas

Mark R. Bowie, James M. Barker, and Stephen L. Peterson

Geology and industrial uses of Arizona1s volcanic rocksJohn W. W8lty and Jon E. Spencer • • • • • • • ••••••

Locating, Sampling, and evaluating potential aggregatedeposits

leo LanglandSOlar salt in Arizona

Jerry Grott • • • •

Bentonite and specialty sand deposits in theBidahochi Fbrmation

Ted H. Eyde and Ian T. Eyde • • • • •

iv

Abstracts

Ramanjaneya, and Gerald Allen •

the southern portion of Searles

• • • • 130

in the

. . . .

129

128

. . . .

. . . . .. . . .

. . . . . . . . . .

Mexico's industrial mineralsJoaquin Ruiz and Bjrnundo Berlanga • • • •

Approach to locating high-quality aggregatesBasin - Range Province

James R. Miller, G.

Geologic evaluation oflake, cal ifornia

K. N. Santini •••Raw materials and the manufacture of vitrified claypipe in Arizona

Ibn t'brris . · . . . . 131

The Bowie chabazite deposit'led H. Eyde and IE.n T. Eyde • • • • • • • • • • •

Arizona Portland Cement Obmpany's Rillito operationJ. W. Ra.ins ..•...•... ,e • • • • • • • •

· . . . .· . . . .

133

134

v

__________________rl

Mining and the Environment:finding Common Ground

Jim DmnDunn Geoscience Cbrporation

5 Northway Lane NorthLatham, NY 12110

ABSTRACT

Fbr decades many of us will are associatedwith the mineral industry have tried to showthe public its economic and strategic impor­tance. Some of the mineral industry's propo­nents have been politically powerfUl figuresand have been widely quoted. Yet, as measuredby public opinion, legislative support, oralmost any other standard, our efforts havebeen inadequate.

It is apparent that a set of environmentalbeliefs that discredit industry, firmly heldby a number of idealistic persons, has hadwider coverage in the media and in schoolsthan has the mineral industry's message. Al­though the fervor of our idealistic friends isoften unfounded and, their stands unscien­tific, they must be considered seriously.Unless we address the issues in terms theidealists will understand, the mineral indus­try will have little influence on them or onthe general public.

A striking thing is that, quite often,translation of idealists' views into actionhas been counterproductive. The reason isobvious. Excessive amounts of money andenergy have been spent on relatively minorproblems. The common resul t is that largerproblems have been created.

It may be possible to help anti-industryidealists understand their own dependence onminerals, and thus render their views morerealistic, if they are shown more effectiveways to reach their stated goals. If thosegoals can be shown to be held in common by allsensitive human beings -- including those inbusiness and industry -- the dialogue becomesone of illw to achieve common ends.

Individual mining companies acting bythemselves have little possibility of success,and companies working in unison through tradeassociations have not been successful. Fur-

it is unlikely that industry in generalbe successful in changing minds unless it

seeks outside help. But friends among thosewho influence public opinion have been hard tofind. Historically, help from media hasproven difficult to get. Nor has enough helpfrom educators been forthcoming.

Yet, a war is going on in the technolog­ical, philosophical, and political trenches,even though much of the public is not aware ofit. Fbr the first time in years, there is now

I

a significant and growing number of eloquentand brilliant thinkers on the side of freeenterprise and industry, many of them environ­mentalists, but without the anti-industrymind-set. They have had remarkably littlehelp from the private sector or even from thepresent administration. Industry may do farmore for itself in the long run by encouragin;]these brave but bruised individuals and theirorganizations than by trying to work alone.'!hese friends of free enterprise are workin;]against a seemingly stacked deck relative tomuch of the media, the bureaucracy, and theeducational system. However, despite theirproblems, their success to date has been re­markable. With more cooperation from industrythey should do even better.

Ca.1MENTARY

Early this January I was taking a limou­sine to Washington, D.C.' s National Airportand found myself alone with a well dressed,dignified gentlemen of about 70 who got onfrom one of the better Washington hotels. Itturned out that he was from phoenix and thathe was very much concerned with a series ofthings. Ha was worried about the inequalitiesof wealth between the rich and poor people inthe U.S. and between rich and poor nations.He felt that corporations, particularly somemultinational corporations, should pay moretaxes. Ha also expressed concern about uncon­trolled industrial pollution and its effectson human health. As you might suspect, ourconversation was lively.

Based on that short conversation, I thinkthat I can guess much about why he was inWashington, what he may have done for aliving, and what else he may believe. And,most important to us, what impact he andothers like him have on the mineral industryand on industry in general.

First, I suspect he was in Washingtonlobbying for an environmental or social cause,possibly representing a group in Arizona, hishome state.

Second, I suspect that a career in educa­tion and government allowed him to develop hisparticular anti-industrial brand of idealism.

Third, I suspect that he subscribes to aspecial set of environmental beliefs. Forinstance, he may bel ieve: (1) that industrycauses most cancer, (2) that industry is

omy, the national defense, or to the qualityof life:' In a survey conducted by OpinionResearch Cbrporation only 16% of the Americanssampled felt familiar with mining. In anopinion section, 62% said that mining wasdangerous and unhealthy, and 43% believed thatit damaged the environment. Q1ly one in sevenpersons viewed mining as helping industry toimprove the energy situation.

The bottom line is on the D9cember 17,1984, Business Week cover. It reads: "TheD9ath of MiningYOf course, environmentaland regulatory pressures are not the wholeproblem, but they make a significant contribu­tion.

Has it occurred to you that we may bedoing something wrong? It certainly hasoccurred to me that I have. For one thing, Isuspect that the people we have tried to reachmay not even have been aware that we weretalking to them, and even if they were, thewords certainly had no measurable influence.Further, I see now that the words from themany of us who have spoken up have been large­ly directed toward reducing the impacts ofsymptoms. Unfortunately, there is almost aninfinite number of syOmptoms that can resultfrom our common disease. I will suggest todaythat we should consider the disease, not thesymptoms.

One problem that we may have failed toconsider sufficiently is: can we realisti­cally expect to educate people like my limou­sine friend only about our particular narrowinterests? Perhaps our attempts at educationshould be broader than this and be put intheir terms and framed in their scale ofvalues. I think doing otherwise has resultedin failure in the past and assures failure inthe future.

I would like to suggest today that thereis a sound rationale for counteracting extremeenvironmental beliefs and I suggest that myfriend in the limousine may understand andappreciate that rationale. I will also sug­gest how you may start a dialogue with him.And I will point out what you already know:it won't be easy. But I also suggest that youare now on the front of a favorable wave andwith a little help from your friends, you maybenefit enormously from it; most imr:ortant, inmy view, America can benefit enormously fromit.

First, to understand the man in the limou­sine. Clearly, he is idealistic and hisidealism leads him to expect perfection, al­most as though he is somehow owed perfection,a society, an environment, an economy, a po­litical system with no blemishes.

Basically, of course, the idealists -­those with unrealistic expectations -- areconcentrated among those who do not work atcreating wealth. EXamples are the young andinexperienced, and those older persons withcareers in academia and government. In addi-

2

spewing wastes into the air and water and willultimately poison us all, (3) that our nationis beset withproblems caused by technologyand the profit motive, (4) that we are des­troying our forests, wildlife, fish, andsoils, (5) that we are depleting our own andthe world's energy and mineral resources,especially those of the poor countries, (6)that almost any sort of development is bad,especially mines, and (7) that mining is badfor the environment, and probably it is notreally necessary, especially in our so-calledpost-industrial era. I could go on but youget the picture.

I suggest that my friend in the limousinehas one other important bel ief. I think thathe considers himself to be a good, patrioticAmerican and is trying to do his best for ourcountry and the world.

Finally, he and others like him are re­sponsible for many of the problems which besetthe mineral industry and, of course, industryin general.

Do we have any basis for believing that wecan change the minds of this man or hisfriends? Can we say anything that he willhear? Keep in mind that if you actually canreach him, you might just find that opening upa new mineral deposit could be easier or thatexploration in wilderness areas might justbecome possible, or you could find that someof the more oppressive and unrealistic regula­tions will diminish.

But reaching him has not proven easy. Wein the mineral industry have tried education,with such influential people as former secre­tary of State Alexander Haig talking eloquent­ly about the resource war and the strategicimplications of not developing our minerals.The American Institute of ProfessionalGeologists' "Metals, Minerals and Mining"(1981) was an attempt to educate the public.People like Don Fife (1982) from Californiashowed that being cut off from access to ourmineral resources will cost future generationsof Americans trillions of dollars. TheNorthwest Mining Association at theirD9cember, 1984, meeting devoted a full sessionto the so-called wilderness problem. Throughthe years there have been many such sessions.We have talked often about the cost in jobs,Arizona being a particularly good example.And we have talked of the folly of laws andregulations which seem at times to be only forthe purpose of destroying an industry thatprovides vital commodities to society.

But how successful has all of this effortbeen?

First, even under the current administra­tion you find still more areas being givenwilderness designation which excludes evenmineral exploration. In addition, accordingto the January 1982 issue of Engineering &Mining Journal, "Only 30% of all Americansview mining as necessary to the national econ-

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tion, because it is easier to be idealistic ifyou do not have to worry about money, suchidealists tend to concentrate among the well­educated middle and upper classes, the long­time weal thy. The wish of many of the ide­alists for a better world makes them vulnera­ble to those who know how to exploit theirhigh motivations. The mind-set of the ide­alists is explained in a quote in CaliforniaMining (1984) from the famous motivationalpsychologist Abraham Maslow: "In a word, wetend to take for granted the blessings wealready have, especially if we don't have tostruggle or work for them. The food, thesecurity, the love, the admiration, the free­dom that have always been there, that neverhave been lacking or yearned for tend not onlyto be unnoticed but also even to be devaluedor mocked or destroyed •••"

Because the idealists tend to be well off,they are also well-educated. one may wonder,if they are so well educated, how come theyare so unrealistic? Should not education leadto enlightenment? The california Mining arti­cle gives some clues. Quoting work byInglehart (1977) they conclude that manypeople are" ••••buffered from and unaware of,the problems of goods production and naturalresources except in the most theoretical way.As (they) become bet ter educated, (the i r)goals and problems." Herman Kahn has calledthis "educated incapacity" and pointed outthat it has led to the paradox that the moreovno.~r, or at least more educated a person,

more likely he is to be affected by"educated incapacity". I suggest that the

class has always known this.All of this, of course, is well known toSOviets. Hede Massing, who broke with the

party in 1981, said in an interviewcanada: "An idealistic approach works best

the privileged of America. It would beimpossible to recruit the working class

and middle class. COmmunism appealsthe elite ••••" (Stevenson, 1984, p. 192).Most, but obviously not all, of the ide-

istic environmental extremists who exhibitanti-industry syndrome are patriots whohonestly trying to do what they believe is

These are the people you may be able tobecause, as fellow-Americans, we want

things: a better environment, less.cancer and better health, less poverty, etc,

common goals we now have a basis for aabout how best to achieve our common

us now examine some of the idealists',Ff:~v.~~ to solve these problems we have in

because that is where they really needIn each of the following cases I will

lUgl;jeE;t that by concentrating efforts on sol­ing only a relatively minor component of al:"()blem, or by expecting perfection, a muchilrger problem has been or will likely bel:"eated, i.e., in each case the problem-

3

solving effort has been counterproductive inits own stated or implied terms.

First, cancer. The ideal is no cancer.Absolutely no one is against wiping outcancer. A logical step -- at least in manypeople's minds -- has been the total elimina­tion of all cancer-causing agents. The battlecry has been "one fiber of asbestos can killyou" or "one molecule of a carcinogen can killyou". This is probably true. In a recentletter to Science, Norman Gravitz of theEdpidemiological Study Section, Californiar:epartment of Health services, agreed that the"one molecule can kill you" concept is,strictly speaking, correct (Gravitz, 1984) •From epidemiological data he calculated, as anexample, that one molecule of benzene consumedin a liter of water per day over a lifetimecarries with it a probability of 10-22 thatyou will get cancer from it. Because theworld population is 5 x 109 the odds of anyperson living in the world today gettingcancer from such exposure are 5 x 10-13 or onechance in 50 trillion. We would have tomeasure time in units of the geologic timescale before anyone got cancer from such ex­posure. Saying that one fiber of asbestos orone molecule of a carcinogen can kill you islike saying that crossing a street once or asingle falling meteorite can kill you. Thesestatements are true, but they are misleadingif solemnly stated by so-called authorities.

Now, what happens when you apply moderntechnology to the "one-molecule-can-kill-you"concept? We find that we can now detectsmaller and smaller amounts of many carcino­gens and consequently we have a very expensiveindustr ial nightmare, the problem of theshifting zero. As the limits of detectabilitydrop, the acceptable limits for various con­taminants also drop. As our ability to detectless and less improves, standards constantlyshift downward as demanded by the idealisticconcept of perfection -- the "one-molecule­can-kill-you" approach. How far downward?There is no real limit because virtually allcontaminants with measurable vapor pressurecontaminate everything and always have. Prob­ably we are all daily taking into our systemmost poisons or carcinogens produced by manand nature. According to Dr. Raymond P.Mariella, former Dean and Vice President ofthe Loyola Medical Center: "If you look longand hard with currently available techniques,you probably will find vanishingly small con­centrations of potentially toxic ingredientseverywhere in everything."

OUr regulators have attempted to reducethe risk of cancer from industrial products tozero -- the ideal or perfect situation. Vastsums of money have been spent to find indus­trial causes of cancer. In fact, the ToxicSubstances COntrol .Act mandates that this bethe case. Not surprisingly, many are foundbecause that is the expressed major purpose of

so much government-sponsored research. yetless than 5% of all cancer is caused by indus­try's chemicals (Higginson, 1980, p. 187). Byconcentrating on the less than 5% we have doneproportionately less to understand and mini­mize the problems with the 95% attributed toall other causes. For example, we are nowapparently finding that certain substances infood, such as carotene and Vitamin C, areapparently anticancer agents. We also knowthat each culture has its own special types ofcancer but may be seemingly immune to others.What might we have learned had we devoted morefunds to understanding such things?

Thus, excessive zeal applied to less than5% of the causes of cancer may itself be anindirect cause of cancer because it must havereduced the money spent on research on theother 95% of all causes. As Weinberg (1984)said "••••our preoccupation with small efflu­ents of carcinogens from various industrialprocesses represents a serious misdirection ofresources'. Media distortions, at times aidedby members of government, promote hysteria anddisplace real information about what can bedone in everyday living to reduce the likeli­hood of contracting cancer. CX1e has to wonderhow many people have died because of a dis­torted perspective that leads to misdirectedfunding and energy, or misused media space andtime? Trying to solve a relatively minorproblem can, thus, create a larger one.

Having seen how efforts can be misdirectedin handling a major health problem, let's looknow at economics. Ideally there should be nopoverty, no farm or business failures, or noeconomic inequities. Yet is this ideal at allrealistic? As an extreme example, suppose apoor country tried to create this perfectsituation. Instantly one realizes that nopoor country can afford perfection, and toattempt to create and maintain this economicideal would clearly bankrupt the country. wenow suspect that even we, with our greatwealth, cannot afford that economic idealeither. 'Ib try to attain economic perfectionis to threaten national bankruptcy, a condi­tion that would make us all poor. Applyingthe ideal of economic perfection can, there­fore, create the problem it is trying tosolve.

Ibw about nature? If we define nature asperfection, then anything that we do to changenature is defined as creating imperfection,and more people result in more imperfection.This leads to the wilderness concept, leavingnature absolutely alone. This is a form ofthe one-molecule-can-kiU-you concept appliedto the natural environment.

I suggested at the Fbrtml on too Geology ofIndustrial Minerals in 1983 that trying forthe perfect environment at local levels couldcreate much larger environmental problems formuch larger areas. For example, I suggestedthat if we truly solved all of the micro-

4

environmental problems associated with ex­ploiting energy sources, we would not mine

,coal, drill for oil, or mine radioactive min­erals. The result would be an environmentalcatastrophe. Fbr instead of mineral fuels wewould harvest and burn our forests just as allof the poor countries are now doing and justas we ourselves once did before we had ourpresent alternative energy sources. Carbondioxide in the atmosphere would be higher thannecessary, erosion would increase, game woulddecrease, and recreational facilities would belost. Thus the concept of saving the localenvironment from the effects of energy produc­tion would itself be environmentally destruc­tive and would adversely influence the en­vironment of entire regions. I called thisproblem "the dispersed-benefit riddle" al­though calling it the "dispersed problemriddle" may be better.

An example of the counterproductivityofexpecting too much or going for the wrong goalhas occurred at New York City. In the mid­1960' s plans were drawn up for a new sewageplant for the west side of Manhattan so theHudson estuary could be cleaned (Eisenbud,1985). Environmental pressures led to insis­tence that the plant be redesigned to reduceby 90% the biochemical oxygen demand.Results: (1) after 15 years of construction,New York City has found that it has insuffi­cient money for such a plant, and (2) insuffi­ciently treated sewage continues to dtmlp intowaterways and there is little chance that itwill change in the near future. Thus theidealistic expectation of more perfection thancan be afforded has led to the problem's con­tinuing •

The dispersed-benefit or dispersed-problemriddle is obviously far from solved becauseexaggerated and unrealistic environmental con­cern is potentially environmentally destruc­tive; application of the "one-molecule-can­kill-you" concept to cancer research and regu­lations may cause neglect of broader researchon prevention of cancer; attempting economicperfection can make us all poor; attemptingtoo high a level of perfection in sewagetreatment in New York City causes the problemto continue. These are a few examples ofconfused priorities and misdirected effortsresulting from an unrealistic environmental­ism.

These examples are the essence of thedispersed benefit riddle or the other side ofthe coin, the dispersed problem. Trying tosolve environmental problems by attempting toforce conformity to unrealistic goals in prac­tically all cases will increase the very prob­lems we are trying to solve, will adverselyinfluence more people or larger areas than ifwe had utilized our resources more wisely.

A different sort of example of confusedpriorities is clearly seen in the changesthrough the years in the nature of the work

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that my own company, ilinn C?eoscience Cbrp:lr­ation, does. My personal training was di­rected toward being a mineral explorer, acreator of wealth. Most all of DGC's staffhave been trained to develop mineral or waterresources. originally, some 30 years ago whenwe began, almost all of our work was relatedto the production of wealth. Now, however,over 95% of our work is directed towardreducing the impacts of regulations, many ofwhich are oppressive and unrealistic. Asscientific entreprenuers, we responded to achanging world rather successfully. In fact,had we not done this we would now be eithernon-existent or very small. But what hasreally happened is that a group of peoplelargely trained to create wealth or developresources is now using too much of its talentto help people stay even or lose minimally.We, as a company, have benefitted; but theUnited states has lost. Our situation on asmall scale is, I think, an accurate depictionof what has happened to much of our nation.Vast amounts of energy seem to have been mis­directed.

Why are so many attempted solutions tosocial and environmental problems counter­productive in their own terms? In each case,concentrating on a small facet of a problemcreates a larger problem. This appears to bea rule, applicable to many, many situations.We all know that if a company diverts itsenergy to nonproductive trivia it will soon goout of business. Keeping your eye on the ballis the game.

It is easy to see why so many of ourenvironmental laws are questionable: theyoften are based on pop-science and hysteria.There is no way such laws could have beenreasonable, oould have really solved problems.They were based on apocalyptic pronouncementsof the environmentalist of the 1970's. Recallthat the influential environmentalist, Profes­sor Paul Erhlich of Stanford Uliversity, oncesaid in a scenario for the future that theoceans would be dead by 1979, that there wouldbe massive world-wide starvation by 1985, thatlife expectancy for "Americans born since 1946(when DDT usage began) would be 42 years by1980" (Ehrlich, 1969). It is useful to knowthat oceans are still alive. It is useful toknow that the world's per capita food produc­tion has increased about 1% per year since1948 according to the UN'S Food and Agricul­ture organization (Osterfield, 1984). It isalso useful to know that a book by the WorldHealth Organization (1979) concludes: "Noharmful effect has ever been reported in thevector control operators who have applied DDTduring the past three decades in public healthprogrammes" (p. 180), and" •••the excellentsafety record, never matched by any otherinsecticide used in antimalaria campaigns,other vector oontroi programmes, and agricul­ture ••••" (p. 20). Further, DDT has saved

5

millions of lives through malaria control.Remember that Professor Barry Commoner,

Director of the Center for the Biology ofNatural Systems at Washington University atst. Louis, said that "In the process ofcreating new goods and services technology isdestroying the country's capital of land,water and other resources as well as injuringpeople" (Efron, 1984, p. 36). It is useful toknow that the most severe degradation of land,water and other resources and, the greatestproblems with hwnan longevity, were then, andhave always been, in the low technologycountries. Further, for the past 100 yearsmineral resources have only become moreabundant as reflected by falling prices interms of Consumer Price Index or relative towages per hour (osterfield, op.cit.).

And on September 11, 1978, Secretary ofHealth, El:1ucation and Welfare Joseph califanosaid that industry is the overwhelming causeof cancer (Efron, 1984, p. 438). Yet, virtu­ally all authorities on cancer in the worldknew his figures were absurd at the time hestated them.

The counter argwnents to most of theapocalyptic predictions have always been knownto various experts in the relevant fields.

But it may be easy to forget that apoca­lyptic views were once so common, so fashion­able and so accepted that when some of ustried to suggest that they may be wrong, ourwords were squelched because they were con­sidered to be "too controversial". This is acurious phenomenon. Aleksandr Sol zheni tsyn(1978), the Soviet author who defected, givesthe reason in a 1978 speech at Harvard:"Without any censorship, fashionable trends ofthought and ideas in the West are carefullyseparated from those which are not fashion­able; nothing is forbidden, but what is notfashionable will hardly ever find its way intoperiodicals or books or be heard in the col­leges". As Albert Einstein once said: "Afashion rules each age, without most peoplebeing able to see the tyrants that rule them".

Things are changing, fortunately. But donot feel too oomplacent. 'Ib my knowledge nota single one of the highest visibility envi­ronmental-thought leaders has ever beencensured by the media, by his oontemporaries,or in any other way. In fact, some seem tohave only been rewarded. Professor Cbmmoner,for instance, formed his own political party,The Citizen's Party, and ran for President in1980; and Paul Ehrlich's work continues to bepublished since his astoundingly incorrect andgloomy predictions.

The apocalyptic thought leaders and themind-set of the excessively idealistic amongus are two factors that cause problems. Athird is the media, which influences us allbut, mostly, the idealistic. Often what wereceive through the media is what has beencalled disinformation. It may have once been

true, or appropriate, but the pressure ofgetting out news often means facts are notresearched and updated. Surprisingly, everystatement by our media may be correct, but oncertain subjects it is easy to draw all wrongconclusions because only one side has beenshown or obsolete examples have been used.Consequently, many of us find ourselves be­lieving strange things like:

We are poisoning ourselves with industrialwastes -- even though we keep livinglonger;Atomic energy is environmentally bad -­even though it is the cleanest, leastpolluting system we have;We are amid a cancer epidemic -- eventhough several types of cancer aredecreasing and cures are ever more effec­tive;Industry is destroying the enviromnent -­even though industry and the wealth itcreates are absolutely the only hope forlong term enviromnental improvement;We are running out of resources, eventhOll]h the history of civilization is thatresources expand as we learn better how tofind and use them. Remember that at onetime our major mineral resource wasprobably flint for arrowheads. And theancient Athenians were concerned withtheir resource base when their per-capitaincome was "eight or ten dollars perannum" (Gramm, 1978) and their use ofresources was a small fraction of thosecurrently used.'Ihe whole problem of counteracting illog­

ical beliefs is compounded by groups thatbenefit from or are able to take advantage ofthe problems created by the inadequate publicinformation system. This includes many p0­liticians, lawyers, government bureaucrats,consulting firms and even some industries. Asan example of the latter, those industriesadvertising products as being "all natural"are exploiting and reinforcing the positionthat mamnade chemicals are, seemingly by defi­nition, hazardous and, therefore, must beregulated more and more. I liken companieslike mine, which benefit from the hysteriaoften produced by inferior information, tobeing like undertakers: someone has to do thework, but that does not necessarily mean thatwe favor killing people.

As mining people, can we improve the sys­tem? can we help the good citizens among theenvironmentalists to achieve their statedgoals? Obviously, changes are needed andpriorities need reordering. The problem isvery difficult because many things need tochange, social attitudes first then some lawsand regulations. If you concentrate yourenergy on problems created by the politicalleft, you find yourself offending many wealthypeople who either cynically gain from theconfusion or have idealistically swallowed

6

much of the contemporary environmental mindset; if you try to change the attitudes of theprivileged who believe silly things, you mayfind yourself offending many of the clergy; ifyou try to show the folly of their positionson cancer, environment, etc., you find your­self seemingly being against motherhood-typecauses. If you try to work throu;:)h your tradeassociations, you may find that those associa­tions have long ago been systematically dis­credi ted. Further, they are not usuallyoriented to deal with conditions in the tech­nologic, economic and philosophic trenches -­and that is where the battles are.

Yet we must try to establish contact withso-called enviromnentalists and in terms theymight understand. Clearly, education is theanswer. Stevenson (1984, p. 246), talkingabout how the Nazis controlled information,said: "But the only safe counterweapon wasfreedom of ideas, freedom of expression, and abelief in the good sense of an informedcitizenry." 'Ihe lead article by K. W. Mote inthe Northwest Mining Association's November,1984, Bulletin is titled "Etlucation is the Keyto the Future of Mining". It is difficult todisagree with Mr. stevenson or Mr. Mote aboutthe importance of education.

Logically, then, we should work throughthe education system. Unfortunately, therecord of our education system has not alwaysbeen reassuring either. Most of us, I assune,have heard strange and incorrect ideas broughthome from school by our children. London(1984), writing in Why are They Lying To OurChildren?, tells us why in his review ofsome70 textbooks used in our schools. He citescase after case where textbooks present thecluster of perspectives that I suggested myfriend in the limousine might have. Londonconcludes that in school texts wealth isassumed to be a given and "not treated as aprecarious endowment that can be affected bybad judgment or reduced throu;:)h trade-offs forother values". And he says further: "Thetexts exploit and bring to the surface thesubterranean fears of the populous. 'Ihere areeither explicitly apocalyptic visions of richnations fighting poor ones in a war of sur­vival or suggestions that environmentalhazards may well doom us all". In their one­sided view, the industrial nations, and par­ticularly the United States, are cast asheavies, exploiting the poor. Clearly, we arecreating some of our problems through oureducation system and our education system iscontributing to what has been called "educatedincapacity" •

Another alternative is working through themedia. To some extent we can and certainlymust. But when we consider that the majornational media have repeated with remarkablecredulity and innocence (or, worse, withoutinnocence) the wildest charges, it is diffi­cult to feel reassured that they will really

nindthemay;ifLons)ur-typeradecia­dis­illyech-s --

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be helpful. Historically they have been partof the problem and not an answer. As PhilipAbelson (1984) says in an editorial inScience: "'!he media are seemingly uncriticalin their treatment of so-called deadly chemi­cals. In recent scares about dioxin they haveroused sufficient public anxiety to force theagency (EPA) to give a minor matter top atten­tion at the expense of more important risks tothe publ ic ". This is another example of thedispersed-problem riddle.

I do not suggest that we give up on theeducation system or the media. I suggest thatwe might get to them via another route I willnow discuss.

So what can we do? Mainly, we can do whatindustry and business have probably failed todo to date: that is, support our friends, thefriends of free enterprise. These are peoplewho see very clearly the problems that I havedescribed and their origins, and as individ­uals and as organizations, have taken on thethankless task of counteracting those prob­lems. Thanks to these brave people it isbecoming more and more difficult for our mediato quote people who say things that are out­rageously at odds with common sense or withscientific, statistical or economic data.

Some change in public perspective hasalready occurred naturally, because the publichas undergone a national opinion pendulumswing. It has become skeptical of thecarcinogen-of-the-month, the apocalyptic pre­diction-of-the-week, and so on. Most people,fortunately, have good sense.

But much of the change has occurred be­cause of brave people like Edith Efron and herApocalyptics; Simon and Kahn and their Re­sourceful Earth; Herbert J. London and his Whyare They Lying To Our Children?; Wattenbergand his The Good News is The Bad News IsWrong; Margaret Maxey' s Reguiatory~fc;rm;- andso:many others; so many good ones, in fact,that it is difficult to have to leave out anyof them. These people are first rate intel­lectuals and they have been attacked by theforces that seem to insist that we believeabsurdities. What keeps our friends going,what helps them to feel less isolated, isreinforcement from others who have also puttheir reputations on the line to counter adisturbing trend. As their numbers grow and,if you will, as dispassionate logic backed byverifiable facts once again becomes fashion­able among intellectuals, they will influenceI,Dsitively the future of the lhited States andthe world.

Industry has given these people and theirassociations relatively little help. In fact,many people in industry have apparently feltthat they could buy off their domestic detrac­tors. Industrially financed foundations havecontributed to industry's potential enemies 26times more money than to their friends (L.Cordia, Heritage Fbundation). '!he belief that

7

industry can buy off its enemies is no morevalid than the concept that we can buy off ournational foes by disarming. Our enemies areimplacable, and they see our contributions tothem as weakness in us and as vindication thatthey are correct.

'Ib repeat, help your friends'. They havetaken the time to get the facts that counter­balance the absurdities with which we havebeen bombarded. They have both credibili tyand intellectual credentials, so academics andidealists are much more likely to hear them.And they get quoted evermore by people in themedia. '!hey can tell the concerned but misin­formed that we absolutely must encourageAmerica's wealth-creating industrial machine,because without it no viable environmental,social or economic programs are possible.They can tell the people of our country thatthe mineral industry must flourish for theeconomic, strategic and environmental benefitof the nation. And they can most effectivelyquestion the whole mass of regulations andlaws that were developed in an atmosphere ofnear mass panic. They can show how so manyregulations and other government activi tiesare counterproductive to solving problems ofhealth, economics, environment, and socialinequi ties that are the concerns of all goodcitizens.

Our free-enterprise friends and philoso­phers may ultimately have enough influence onthe writers of textbooks, on legislators andon the idealists in general so that we as anation will benefit enormously. They are thebest hope for making sensible progress towardachieving the stated goals of the idealistsfor both the future of the mineral industryand the United States in general. They arethe best hope because they are addressing thegeneral problems, not just the problems of themineral industry. They are finding a commonground.

REr'ERENCES

AIPG, Colorado Section, 1981, Metals, min­erals, and mining, 2nd ed.: Golden, CO,American Institute of Professional Geolo­gists, 38 p.

Dunn, J. R., 1983, The dispersed benefitriddle, in Ault, C. H. and Woddard, G. S.,eds., Proceedings of 18th Fbrum on Geologyof Industrial Minerals: Bloomington,Indiana Geological SUrvey occasional Paper37, p. 1-9.

Editor, 1984, Eying the environmentalists, abehavioral study: California Mining,l'bvember. (unable to confirm reference,ed .)

Efron, Edith, 1984, The apocalyptics - Cancerand the big 1 ie: New York, Simon andSChuster, 589 p.

Ehrlich, paul, 1969, Eco-catastrophe:Ramparts, vol. 8, no. 3, sept., p. 24-28.

Eisenbud, Merril, 1985, Health risks and en­vironmental regulation: A historical per­spective, in Maxey, M. N. and Kuhn, R. L.,OOs., Regulatory reform, new vision or oldcurse: New York, praeger publishers, p.

33-52.Fife, D. L., and Minch, J. A., 1982, Observa­

tions on the status and state-of-the-artof the economic geology in the californiaTranverse Ranges: in Fife, D. L., andMinch, J. A., eds., Geology and mineralwealth of the california Tranverse Ranges,annual symposium and guidebook no. 10,october 1982: Santa Ana, CA, South CoastGeological 8:)ciety, p. 8-12.

Gramm, W. P., 1978, D3bunking doomsday: Rea-son, vol. 10, no. 4, p. 24-25.

Gravitz, Norman, 1984, Comment on reply byNicholas A. Ashford, and others, 1984 (inscience, vol. 224, no. 4649, p. 554-556,May 11) to comments on Law and sciencepolicy in federal regulation of formalde­hyde by Nicholas A. Ashford, and others,1983, (in science, vol. 222, no. 4626, p.894-900, NOv. 25): science, vol. 226, no.4678, Nov. 30, p. 1022.

Higginson, John, 1980, Proportion of cancers. due to.occupation: preventive Medicine,

vol, 9, no. 2, p. 180-188.

Inglehart, Ronald, 1977, The silent revolu­tion: Changing values and politicalstyles among western publics: Princeton,Princeton University Press, 482 p.

IDndon, H. T., 1984, Why are they lying to ourchildren: New York, Stein and Lay, 197 p.

osterfeld, David, 1984, The increasing abun­dance of resources: The Freeman, p. 360-377, June.

Simon, J. L., and Kahn, Herman, eds., 1984,The resourceful Earth. A response toGlobal 2000: OKford, Basil BlackwellPublisher Ltd, 585 p.

Stevenson, William, 1983, Intrepid's lastcase: New York, Villard Pooks, 321 p.

SOlzhenitsyn, A. I., 1978, A world splitapart: New York, Harper arrl IbW, publish-ers, 61 p.

Wattenburg, B. J., 1984, The good news is thebad news is wrong: New York, Simon andSchuster, Inc., 431 p.

Weinburg, A. M., 1984, Comment on dietarycarcinogens and anticarcinogens by BruceN. Ames, 1983 (in science, vol. 221, no.4617, p. 1256-1264, sept. 23): science,vol. 224, no. 4650, p. 659, May 18.

WHO Task Group on Environmental Health crite­ria for DDT and its D3rivatives, 1979, DDTand its derivatives: Geneva, Vbrld Healthorganization arrl united Nations Environ­mental Programme, Environmental HealthCriteria 9, 194 p.

8

u­alIn,

urp.n­O-

;4,to11

Geologic Setting of Industrial Rocksand Minerals in Arizona

Stephen J. ReynOlds and H. Wesley PeirceArizona Geological SUrvey

845 N. Park Ave.Tucson, Arizona 85719

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ABSTRACT

Arizona's geologic history is complex,resulting in a diversity of rock types andearth materials, including those of commercialinterest. Regional variations in geologichistory gave rise to three geologic provincesand an inequitable distribution of bothmetallic and nonmetallic mineral wealth. '!heColorado Plateau is largely composed of flat­lying Paleozoic and Mesozoic sedimentary rocksand late Cenozoic volcanic fields and sedimen­tary deposits. Associated resources includegypsum, halite, sylvite, clays, specialtysand, flagstone, volcanic products, and aggre­gate. '!he adjacent Transition Zone features alarge expanse of Proterozoic rocks, economi­cally important Devonian and Mississippiancarbonate rocks, and Tertiary volcanic andsedimentary materials. NOnmetallic resourcesin this province include facing and dimensionstone, aggregate, decomposed granite, chryso­tile asbestos, gypsum, clay, barite,fluorspar, zeolites, and limestone used forlime, cement, and railroad ballast. The Basinand Range Province has the most complex geo­logic history and, therefore, the most diverseassemblage of industrial mineral occurrences.These include halite, gypsum, clay, aggregate,decomposed granite, diatomite, zeolites,perlite, pumice, kyanite, limestone, marble,stone, and others. In addition, young streamdeposits yield vast quantities of sand andgravel, Arizona's most economically importantnonmetallic mineral commodity.

INTRODUCTION

The geologic history of Arizona is bothcomplex and regionally variable. This isreflected by a diverse assemblage of rocktypes, structures, and mineral deposi ts, andby an unequal distribution of industrial rocksand minerals (Peirce - this volume). Thispaper summarizes the geologic evolution ofArizona, highlighting the geologic context ofindustrial rocks and minerals.

GEOLOGIC PROVINCES OF ARIZONA

Arizona consists of three geologic prov­inces - the Colorado Plateau (CP), TransitionZone (TZ) , and Basin and Range Province (BRP)

(Figures 1 and 2; Peirce, 1985). The CP ofnortheastern Arizona is geologically thesimplest, largely because it escaped severeMesozoic and Cenozoic tectonism. At the sur­face, it is largely composed of Paleozoic andMesozoic Sedimentary rocks that regionally dipgently to the northeast (Peirce, 1986). Theunderlying Proterozoic crystalline basement isexposed only in the bottom of Grand canyon andin the Defiance Uplift, but has been pene­trated in numerous drill holes (Peirce andScurlock, 1972). Erupted over the Paleozoicand Mesozoic rocks are Neogene volcanic rocks,consisting largely of basalt with less abun­dant silicic to intermediate flows and tuffs.cenozoic sedimentary deposits are also locallypresent, especially within present valleys andalong the southern edge of the province. '!hestructure of the CP is dominated by a regionalnortheast dip (due in part to pre-Late Creta­ceous tectonism), Late Cretaceous to earlyTertiary folds, especially monoclines, andNeogene normal faults.

In the adjacent TZ, uplift and erosionaltruncation of the northeast-dipping Paleozoicsection has resulted in widespread exposure ofthe underlying Proterozoic crystalline rocks.Much of this erosional unroofing occurred inCretaceous and early Tertiary time, based onthe presence of detritus shed northeastwardonto the CP (Peirce, 1986). The unroofedProterozoic rocks were locally covered byNeogene volcanic and sed imen tary rocks. Anepisode of mostly middle Miocene to Plioceneblock faulting and basin filling was followedby erosional dissection of the basin fillduring Pliocene and younger drainage integra­tion.

The BRP is the most geologically complexregion in Arizona. '!he geologic evolution ofthe BRP was comparable to that of the othertwo provinces during Proterozoic and Paleozoictime, but diverged by early Mesozoic time whenthe region became incorporated into theCordilleran orogen. Multiple episodes ofMesozoic to early cenozoic plutonism, metamor­phism, and regional deformation, includingthrusting, occurred during eastward subductionof various Pacific plates beneath southwesternNorth America. A middle Tertiary episode ofcrustal extension, accommodated by regionallow-angle normal (detachment) faulting, wasfollowed by high-angle normal faulting that

9

+ + -I- -I-

+ + + -I- ...

+ ... + -I-

PROVINCEQUATERNARY AND UPPER TERTIARY SEDIMENTARY DEPOSITS

QUATERNARY AND UPPER TERTIARY VOLCANIC ROCKS

MIDDLE TERTIARY VOLCANIC AND SEDIMENTARY ROCKS

MIDDLE TERTIARY MYLONITIC ROCKS

MIDDLE TERTIARY TO JURASSIC GRANITIC ROCKS

CRETACEOUS AND LOWER TERTIARY SEDIMENTARY ROCKS

MESOZOIC VOLCANIC AND SEDIMENTARY ROCKS

JURASSIC AND TRIASSIC SEDIMENTARY ROCKS

PALEOZOIC SEDIMENTARY ROCKS

UPPER PROTEROZOIC SEDIMENTARY AND IGNEOUS ROCKS

PROTEROZOIC METAMORPHIC AND IGNEOUS ROCKS

Figure 1. Generalized geologic map of Arizona.

10

GEOLOGIC ARIZONA PROVINCESTIME Basin B Range Transition Colorado Plateau

Quaternary. ~<.!)

Sand and Gravel Sand and Gravel .~d5E(/):::l .~

Special clay Q....!E:

Pliocene Peridot Clay (vitrified pipe)0

E Q).. 0

:::l .-= ZeoliteSpecial sand .~ a::

(f) - c .~

Halite; Perlite;0. 0

Gypsum0"-

>.Q) oQ)

r Miocene <.!)N_ "0

Cinder; Pumice; oc

a: Zeolite; RockRock >0

«Oligocene- Clay; Gravel GravelI-

a:w Eocene GravelI-

-----Paleocene Formation of

kyanite etc. andmarble by

Up mtamorphismNot Clay (vitrified pipe)() Cretaceous- Low Lime Not recognized0

NJurassic

Kyanite etc.0 Sandstones(J) protolith Present

WTriassic Gypsum occurrences Rock; Gypsum;

:E Petrified wood;in western Arizona Clay (bentonitic)

Perm'ian Gypsum GypsumFlagstone; Gypsum;

Halite; Potash.c+-

PennsyIvanian-0 Limestone and Shale+-0"-

Lime a.+-c ~ Not generally

MississippianQ) -cE "-

Rock;Q) 0u ~

Cement; Lime

Devonian exposed

CambrianQuartzite (fl ux); Local Iy

Phosphatic (Abrigo)

Quartzite (rock a flux) Asbestos (chrysotile) Asbestos (chrysotile)Quartzite (rock)

Silica; Granite; Granite; Pegmatitej Granite (rock)Feldspar Stone (schist)

2. Time and geographic associations of selected industrial minerals in Arizona.

11

helped block out many of the present-daybasins and ranges.

PROTEROZOIC ROCKS AND THEIR USES

The oldest rocks in Arizona are Protero­zoic volcanic and sedimentary rocks that weremostly deposited between 1.65 and 1.8 b.y.ago. These rocks, which formed in oceanic,island-arc, and continental-shelf settings,consisted largely of an older sequence ofsubaqueous mafic to felsic volcanic and vol­caniclastic rocks with local pelitic units,and a younger sequence of subaerial rhyolite,quartzose clastic rocks, and thick marinegraywackes (Anderson, 1986). Subsequent todeposition, both rock sequences were variablydeformed and metamorphosed into schist,gneiss, mylonite, and other metamorphic litho­logies.

The effects of deformation and metamor­phism are extremely variable, both withinsmall areas and between the three geologicprovinces. This results in a wide variationin the physical properties, and thereforecommercial uses, of Proterozoic rocks. NearMayer in the TZ north of Phoenix, decorativefacing stone is quarried from metarhyolitethat was first hydrothermally altered andmineralized, and then metamorphosed intostrongly foliated schist. Near New River,Slaty to phyllitic Proterozoic rocks are minedfor use in the manufacture of vi trified claypipe (Morris - this volume).

Proterozoic rocks in the BRP in westernArizona represent a deeper exposed level ofthe Proterozoic crust and are generally compo­sitionally banded high-grade gneisses notpresently exploited for industrial uses. Lessdeep-seated Proterozoic rocks in southeasternArizona are dominated by schistose metagray­wacke that is likewise not extensively utili­zed. Industrial uses of foliated Proterozoicrocks, such as for facing stone, apparentlyrequire the spatial ooincidence of a suitableprotoli th and a special history of metamor­phism, deformation, and possibly hydrothermalalteration.

In addition to the metavolcanic and meta­sedimentary rocks, Arizona contains severalgenerations of Proterozoic granitic rocks(Silver, 1978). The oldest generation con­sists of dioritic to granitic plutons emplacedbefore, during, and slightly after deformationand metamorphism at 1.65 to 1.75 b.y. ago.Plutons emplaced before or during deformationcommonly have a variably developed foliation,mylonitic fabric, or metamorphic layering,characteristics that limit the strength of therocks and their potential uses. A relativelyundeformed 1.7-b.y.-old granite located nearPayson in the TZ is used as road metal andfill. Plutons emplaced after deformation,such as a younger generation of undeformed1.45-b.y.-old porphyritic granites, have been

12

locally quarried for dimension stone andcrushed for use as aggregate. A popular cur­rent use is in desert landscaping, as aroundthe State capitol in Phoenix. Screened finesfrom crushed Proterozoic granite are currentlybeing tested for use in IIc l ay" tennis courts.

In the CP, a Proterozoic granite cropsout near the southern end of the DefianceUplift where it is depositionally overlain byPermian strata. '!his very durable rock, rep­resenting part of the Paleozoic Defiance posi­tive area (Peirce, 1976a), was recognized as apotentially important source of crushed rock(Kiersch, 1955, p. 33-35) and SUbsequentlyused extensively for road building.

'!he youngest Proterozoic rocks in Arizonaare 1.1- to 1.2-b.y.-old sedimentary and vol­canic rocks of the Apache Group and TroyQuartzite in east-central Arizona (TZ) andsoutheastern Arizona (BRP), and the GrandCanyon Supergroup in Grand Canyon (CP).Diabase sills and dikes widely intruded theserocks 1.1 b.y. ago, reSUlting in the formationof major deposits of chrysotile asbestos inthe Mescal Limestone of the Apache Group(Wrucke and others, 1986) and to a lesserextent in the Bass Limestone of the Grandcanyon Supergroup. The Mescal Limestone wasalso used as dimension stone for constructionof the 284-feet-high masonry Ibosevelt D3.m inthe TZ. Resistant units in the Apache Groupand Troy Quartzite are also locally crushedfor aggregate. Additional commercial uses ofrocks in the Apache ~oup are possible, sincenew scientific discoveries are still beingmade, such as the recognition of K-metasoma­tized tuffs in the sequence (Wrucke andothers, 1986, p. 16).

PALEOZOIC ROCKS AND THEIR USES

During Paleozoic time, Arizona was partof the North American craton and received agenerally thin (1 to 1.5 km thick) cover ofcarbonate and clastic rocks (Pe irce, 1976a).The stable cratonic setting was interrupted ~n

Pennsylvanian to Early Permian time whenuplifts and basins formed during tectonism inthe ancestral Rocky Mountains. Paleozoiccarbonate rocks, especially those of Missis­sippian age, are util ized in two cementplants, one in the BRP near Tucson and anotherin the Verde Valley of the TZ. They are alsoa source of railroad ballast and lime (nearNelson) in the TZ and are used in the copperindustry for lime and flux stone. Otherresources in Paleozoic rocks include (1)potash and salt (sylvite and halite) in thePermian l:blbrook Basin of the CP (Peirce andGerrard, 1966); (2) gypsum in the permianKaibab Formation, the youngest Paleozoic uniton the CP; and (3) flagstone from the PermianCbconino sandstone (CP). In addition, liqui­fied petroleum gas is stored in undergroundsolution cavities in evaporite zones in the

andcur­

'oundEinesmtlyrts.'ropsance.n byrep­

x:Jsi­as arockntly

.zonavol­Troy

andrandCP) •:heseltion,s inroupsserrand

was'tionm inroupsheds ofince9ing:>ma-and

?artad a'" of6a) •d invhenn inwic,is­lenttherilsolear)per:her

(1)theand

lianunitlian=IUi ­lUndthe

upper part of Supai Fbrmation, above the FbrtApache Member (Peirce, 1981; Peirce and Wilt,1970, plate 15.).

The thermal history of Paleozoic rocksvaried significantly from area to area(Wardlaw and Harris, 1984; Reynolds andothers, in press). This is partly revealed bythe color-alteration index (CAI) of conodonts,a phosphatic microfossil that systematicallychanges color when heated. CAI studies indi­cate that Paleozoic rocks in the CP and north­eastern TZ were only raised to temperatures ashigh as 50 to 100 °c during post-Paleozoicthermal events (Wardlaw and Harris, 1984). Incontrast, Paleozoic rocks in the BRP widelyreached temperatures of 2500 C and higher. Asa result, Paleozoic quartzose clastic rocks inthe BRP tend to be quartzites. Carbonaterocks in the BRP are locally marbles, espe­cially near large intrusions or where thrust­related deformation and metamorphism occurred.Quartzite is used for aggregate and smelterflux, whereas crushed marble is used for live­stock feed additive, white pool sand, andvarious other applications.

TRIASSIC AND JURASSIC ROCKS AND THEIR USES

Triassic history of the BRP is poorlyknown because Triassic rocks are not widelypreserved or recognized (Peirce, 1986; stewartand others, 1986). Quartzose clastic rocksprobably correlative with Triassic MoenkopiFormation have been recently recognized inwest-central Arizona (Reynolds and others,1987), and these rocks locally contain gypsi­ferous zones. By Early to Middle Jurassictime, much of the BRP evolved from a cratonicsetting into part of the Cordilleran orogen(Coney, 1978; Dickinson, 1981). Jurassicrocks of the BRP include widespread silicic tointermediate ash-flow tuffs, flows, and vol­caniclastic rocks, continental sedimentaryrocks ranging from fine-grained red beds tocoarse sedimentary breccia, and several gener­ations of granitic plutons (Tosdal and others,1987). Jurassic volcanism and magmatism waslocally accompanied by intense hydrothermalalteration and metasomatism that extensivelyleached mobile elements from the affectedrocks, leaving high concentrations of lessmobile elements, such as Al, Ti, and P. Meta­morphism either during or after metasomatismproduced highly aluminous rocks composed ofquartz, kyanite, andalusite, pyrophyllite,rutile, dumortierite, tourmaline, and otherminerals (Reynolds and others, in press).These quartz-kyanite rocks were mined in adja­cent southeastern California for use as arefractory material and may have further eco­nomic potential because half of the knownoccurrences in Arizona were discovered since1980. Potentially commercial pyrophyllitedeposits may also exist, based on the presenceof over 100 m of pyrophylli te in exploratory

13

drill holes in the central Dome Bock Mountainsof western Arizona (J. Loghry, 1987, personalcommunication). The pyrophyllite occurs inaltered Jurassic volcanic rocks and may berelated to either Jurassic or Late Cretaceousmagmatism and alteration.

In contrast to the BRP, the CP regionremained tectonically stable, but receivedabundant detritus derived from an orogenicbelt somewhere to the south and west (Peirce,1986; Stewart and others, 1986). TriassicMoenkopi Formation, the oldest Triassic uniton the CP, has been used for dimension stoneand contains interbedded gypsum in north­western Arizona (CP). The overlying UpperTriassic Chinle Fbrmation, which records theinflux of volcanic ash and detri tus from thesouth and west, has abundant ash-derived claysand semiprecious petrified wood; the basalShinarump Conglomerate Member is used foraggregate. Overlying the Chinle Fbrmation areJurassic continental and marginal marine sedi­mentary rocks of the Glen Canyon Group, SanRafael Group, and Morrison Fbrmation.

CRETACEOUS AND EARLY TERTIARY ROCKSAND THEIR USES

Beginning in the Late Jurassic and con­tinuing into the Early Cretaceous, faulting inthe BRP created basins in which thick sequen­ces of mostly nonmarine clastic rocks accumu­lated (Dickinson, 1981). These sequencesinclude the Bisbee Group in southeasternArizona and the McCby Mountains Fbrmation inwest-central Arizona. The Mural Limestone, amarine limestone in the Bisbee Group, is usedin the production of lime near Douglas insoutheasternmost Arizona.

A younger, unrelated sequence of Creta­ceous rocks occurs on the CP and includesnonmarine and marine strata of the Dakotasandstone, the Upper Cretaceous Mancos Shale,and the Mesa Verde Group. The latter rocksare mined for coal on Black Mesa and forkaolinitic shale near the Mogollon Rim ineast-central Arizona (Morris - this volume).

In Cretaceous to early Tertiary time,southern and western Arizona was the site ofwidespread large-scale folding and thrustfaulting (Drewes, 1981; Haxel and others,1984; Reynolds and others, 1986a). Deforma­tion was locally accompanied by metamorphismthat converted Paleozoic and Mesozoic supra­crustal rocks to schist, phyllite, marble,quartzite, and calc-silicate rocks (Reynoldsand others, in press).

Late Cretaceous to early Tertiary (lara­mide) tectonism was also accompanied bycaldera collapse due to eruption of extensiveash-flow tuffs, by construction of andesiticstratovolcanos, and by emplacement of plutonsranging from subvolcanic porphyries to mid­crustal muscovite-bearing granites. Hydro­thermal alteration and mineralization occurred

near many porphyry intrusions (Titley, 1982) ,forming large porphyry copper deposits andlocal higher-level alunite and kaoliniticoccurrences within wall rocks of the intru­sions. Altered zones associated with a LateCretaceous granite in the San Tan Mountainssouth of Phoenix are used for decorativelandscaping material. During and subsequentto laramide tectonism, much of the TZ and BRPwas uplifted, resulting in shedding ofdetritus (Rim gravels) onto the CP and devel­opment of a widespread erosion surface beneathmiddle and upper Tertiary rocks.

MIDDLE TERTIARY ROCKS AND THEIR USES

After an Eocene volcanic quiescence,volcanism swept westward across the BRP,starting in southeastern Arizona at about 30to 35 Ma and reaching western Ari:wna by 20 to25 Ma (Coney and Reynolds, 1977; Shafiqullahand others, 1980; Reynolds and others, 1986b).Silicic ash-flow tuffs and flows are ubiqui­tous within middle Tertiary volcanic fields,along with locally abundant basaltic andandesitic rocks. Vblcanism was accompanied atdepth by the emplacement of granitic plutonsand extensive dike swarms.

Middle Tertiary tectonism was dominatedby major crustal extension, generally accom­modated by large-scale transport on regional,gently dipping normal faults, called detach­ment faults (Davis and others, 1986; Spencerand Reynolds, 1987). Gently dipping myloniticfabrics in the footwall of many detachmentfaults were formed by an earlier phase ofdeep-level ductile shear along the fault:wnes. Rocks above detachment :wnes are com­monly cut by normal faults into numeroustilted fault blocks that are truncated down­ward by the detachment fault. Half-grabensbetween the crests of adjacent fault blockslocally received thick accumulations ofclastic and volcanic rocks.

The main industrial mineral commoditiesin middle Tertiary rocks are (1) perliteassociated with silicic flows; (2) clays usedin the production of cement and brick, and inearthen-construction (adobe and rammed earth)homes; and (3) minor vein barite. SOme middleTertiary volcanic fields also contain pumiceand "Apache Tears ," semiprecious obsidiannodules that occur within perlite and devitri­fied rhyoli te.

UPPER TERTIARY AND QUATERNARY ROCKSAND THEIR USES

Middle Tertiary extension along low-angledetachment zones was followed by the Basin andRange disturbance, a late Tertiary episode ofhigh-angle normal faul tirg that outlined manyof the present-day basin-and-range-type faultblocks (Eberly and Stanley, 1978; SCarbor01..gh

14

and Peirce, 1978; Shafiqullah and others,1980). Basins that formed over downdroppedblocks were filled with detritus eroded fromthe flanking upthrown horst blocks. Coarsedetritus deposited near the mountain frontsgraded into finer grained clastic depositstoward the interior of the basins. Up to 3 kmof nonmarine evaporite deposits, mostly haliteand anhydrite, are interpreted to be presentin certain late Tertiary basins (Peirce, 1974,1976b, 1981). Salt (halite) in the Illke Basinnear Phoenix is utilized for two purposes:(1) as a source of salt products produced bysolution mining and solar evaporation; and (2)for storage of propane and butane in under­ground solution cavities. A similarly thickhali te sequence in the Red Lake basin ofnorthwestern Arizona will probably also beutilized someday.

Of the approximately 150 basins withinthe BRP and TZ of Arizona, few have beenadequately explored by drilling. The poten­tial for valuable chemical precipitates, suchas chlorides, sulfates, and borates, thoughunknown, may be substantial. In addition, thedeeper parts of many basins may contain salinebrines, inasmuch as the salinity of ground­water commonly increases with depth (Peirce,1969 ,1976b).

On the Colorado Plateau, the Basin andRange disturbance did not produce majorbasins, but did result in substantial lateTertiary to Quaternary offset on faults innorthwestern Arizona. Changing tectonic orclimatic conditions also caused the formationof Pl iocene Lake Bidahochi along what is nowthe Little Colorado River Valley. Fluvialsands derived from the adjacent Defiance Up­lift were deposited in the Bidahochi Fbrmationand are properly sized and rounded to be usedas hydrofrac sand in petroleum production.Below the sands are special clays that formedby alteration of air-fall tuffs and that havebeen mined since 1925 (Eyde and Eyde - thisvolune)

sedimentary units (basin fill) depositedin late Tertiary basins and on buried pedi­ments flanking the range fronts locally con­tain tuffaceous rocks that have been alteredto zeolites (Jett, 1978). The BJwie chabazitedeposit in southeastern Arizona, because ofvaluable commercial production, is the bestknown occurrence of these (Eyde, 1978;Sheppard and others, 1978, p. 319-328). Basinfill also hosts deposits of gypsum and diato­mite in the BRP and occurrences of gypsum andzeolites in the TZ.

Another manifestation of late Cenozoictectonism was volcanism in all three geologicprovinces. Basaltic volcanism became wide­spread 15 m.y. ago (Shafiqullah and others,1980; Reynolds and others, 1986b) and haslocally continued into the Holocene. On theCP, basaltic cinders quarried from Quaternarycinder cones in the San Francisco and

lers,ppedfromarseontssits3kmllitesentL974,lasin,ses:,d by:I (2)der­hick1 ofo be

thinbeenten­such::lUgh

the.lineund­.rce,

andljorlate:; incortionnowlial

Up­tionusedion.rmedhavethis

ited~di­

con­~red

zitee of)estl78;asinato-and

wicogiclde­ers,hasthe

naryand

Springerville volcanic fields are widely used(WeIty and Spencer - this volume).

In the BRP, basaltic cinders were oncemined in the san Bernardioo Valley of extremesoutheastern Arizona. Basaltic rocks arelocally crushed for road material and are usedin the fabrication of glass wool at CasaGrande. Basaltic boulders in talus aprons areharvested for rip-rap, such in the Palo U3rdeHills west of Phoenix. Also, gem-qualityperidot is recovered from mantle inclusions ina basalt flow on Peridot Mesa in the Sancarlos Indian Reservation.

Although basalt is by far the most abun­dant Upper tertiary to Quaternary volcanicrock, dacitic to rhyolitic flows and tuffsoccur in the san Francisco and White Mountainsvolcanic fields (CP). Pumice from the SanFrancisco volcanic field was blended withcement as a pozzolan during the constructionof Glen canyon Dam, and material suitable forlight-weight aggregate is being transported toPhoenix.

As basin-and-range-style faulting de­creased in intensity during the last 4 m.y.,internally drained (closed) basins becameintegrated into the regional drainage networkemptying into the newly opened Gulf ofCalifornia. Sand and gravel deposited onpediments and along rivers and washes are theState's most important source of aggregate(Langland - this volume).

CCNCIDSIONS

The complex geologic history of Arizonahas resulted in a great diversity of knownindustrial rock and mineral deposits. Varia­tions in geologic history between the State'sthree provinces are reflected in an unequaldistribution of geologic materials andassociated nonmetallic products. Much remainsunknown about the geology of Arizona, espe­cially in the Basin and Range Province -­major geologic discoveries are still beingmade and significant geologic problems remainunresolved. There is, therefore, much poten­tial for future discoveries of industrialmineral deposits, both of deposit typesalready known and of new types not yet widelyanticipated. It is fortunate that most of theState's population growth is in the geologi­cally complex Basin and Range Province, whereindustrial minerals production, and futureopportunities, are greatest.

Anderson, Phillip, 1986, Summary of theProterozoic plate tectonic evolution ofArizona from 1900 to 1600 Ma, in Beatty,Barbara, and Wilkinson, P. A:-K., eds.,t'rontiers in geology and ore deposits of

15

Arizona and the Southwest: Arizona Geo­logical Ebciety Digest, v. 16, p. 5-11

COney, P. J., 1978, Plate tectonic setting ofsoutheastern Arizona, in Callender, J. F.,and others, eds., Landof Cochise: NewMexico Geological Ebciety 29th Field COn­ference Guidebook, p. 285-290.

Coney, P. J., and Reynolds, S. J., 1977,Cordilleran Benioff zones: Nature, v.270, p. 403-406.

Davis, G. A., Lister, G. S., and Reynolds, S.J., 1986, Structural evolution of theWhipple and Ebuth Mountains shear zones,southwestern Uni ted States: Geology, v.14, p. 7-10.

Dickinson, W. R., 1981, Plate tectonic evolu­tion of the southern Cordillera, inDickinson, W. R., and Payne, W. D., edS:-;Relations of tectonics to ore deposits inthe southern COrdillera: Arizona Geologi­cal SOciety Digest, v. 14, p. 113-135.

Drewes, H. D., 1981, 'I8ctonics of southeasternArizona: U.S. Geological Survey Profes­sional Paper 1144, 96 p.

Eberly, L. D., and Stanley, T. B., Jr., 1978,Cenozoic stratigraphy and geologic historyof southwestern Arizona: GeologicalSOciety of America Bulletin, v. 89, p •921-940.

Eyde, T. H., 1978, Bowie zeolite, an Arizonaindustrial mineral: Arizona Bureau ofGeology and Mineral 'I8chnology Fieldnotes,vol. 8, no. 4., p. 1-5.

Jett, J. H., ed., 1978, Arizona zeolites:Arizona D3partment of Mineral ResourcesMineral Report no. 1, 40 p.

Haxel, G. B., Tosdal, R. M., May, D. J., andWright, J. E., 1984, Latest Cretaceous andearly 'I8rtiary orogenesis in south-centralArizona; thrust faulting, regional meta­morphism, and granitic plutonism: Geo­logical Society of America Bulletin, v.95, p. 631-653.

Kiersch, G. A., 1955, Mineral resources,Navajo-Hopi Reservations, Arizona-Utah,vol. III, construction materials, geology,evaluation, and uses, with sections byJohn C. Haff and H. Wesley Peirce:Tucson, University of Arizona Press, 81 p.

Peirce, H. W., 1969, Salines, in Mineral andwater resources of Arizona: ArizonaBureau of Mines Bulletin 180, p. 417-424.

, 1974, Thick evaporites in the----~B-a-s~i-n--a-n-d Range Province, Arizona, in

Coogan, A. H., ed., Fourth symposium onsalt, vol. 1: Cleveland, Northern OhioGeological Ebciety, p. 47-55.

, 1976a, Elements of Paleozoic----------~-tectonics in Arizona: Arizona Geological

SOciety Digest, v. 10, p. 37-57., 1976b, 'I8ctonic significance of

---~--Basin and Range thick evaporite deposits:Arizona Geological SOciety Digest, v. 10,p. 325-339.

, 1981, Major Arizona salt depoe­--"""'"i-t-s-:-Ar-izona Bureau of Geology and Min-

eral Technology Fieldnotes, vol. 11, no.4, p. 1-4.

, 1985, Arizona's backbone, the---=Tr-a-n-s-'i'-'t-:i-on ZOne: Arizona Bureau of Geolo-

gy and Mineral 1echnology Fieldnotes, voL15, no. 3, p. 1-6.

, 1986, paleogeographic linkage----;be---;tC-w-e-e-n---=-Arizona's physiogeographic prov­

inces, in Beatty, Barbara, and Wilkinson,P. A. K:; eds., Frontiers in geology andore deposits of Arizona and the southwest:Arizona Geological society Digest, v. 16,p. 74-82.

Peirce, H. W., and Gerrard, T. A., 1966,EWapori te deposits of the Permian H:>lbrookBasin, Arizona in Rau, J. L., ed., Secondsymposium on salt, vol. 1: Cleveland,IDrthern Chio Geological SOciety, p. 1-10.

Peirce, H. ·W., and Scurlock, J. R., 1972,Arizona well information: Arizona Bureauof Mines Bulletin 185, 195 p.

Peirce, H. W., and Wilt, J. C., 1970, Oil,natural gas, and helium, in Peirce, H. W.,and others, Coal, oil, natural gas,helium, and uranium in Arizona: ArizonaBureau of Mines Bulletin 182, p. 43-101.

Reynolds, S. J., Richard, S. M., Haxel, G. M.,Tosdal, R. M., and Laubach, S. E., inpress, Geologic setting of Mesozoic andCenozoic metamorphism in Arizona, inErnst, W. G., ed., Metamorphism andcrustal evolution of the western UnitedStates: Englewood Cliffs, New Jersey,Prentice-Hall.

Reynolds, S. J., Spencer, J. E., and D3Witt,&I, 1987, Stratigraphy and U-Pb geochro­nology of Triassic and Jurassic rocks inwest-central Arizona, in Dickinson, W. Ro,and Klute, M., eds., Mesozoic rocks ofsouthern Arizona and adjacent areas:Arizona Geological society Digest, v. 18(in press).

Reynolds, S. J., Spencer, J. E., Richard, ~.

M., and Laubach, S. E., 1986a, MeSOZOICstructures in west-central Arizona, inBeatty, Barbara, and Wilkinson, P. A. K.,eds., Frontiers in geology and ore depos­its of Arizona and the SOuthwest: ArizonaGeological SOciety Digest, v. 16, p. 35­51.

Reynolds, S. J., Welty, J. W., and Spencer, J.E., 1986b, volcanic history of Arizona:r'ieldnotes, v. 16, no. 2, p. 1-5.

Scarborough, R. S., and Peirce, H. W., 1978,Late Cenozoic basins of Arizona, inCallender, J. F., and others, eds., Landof Cochise, southeastern Arizona: NewMexico Geological society Guidebook, 29thField COnference, p. 157-163.

16

Shafiqullah, M., Damon, P. E., Lynch, D. J.,Reynolds, S. J., Rehrig, W. A., andRaymond, R. H., 1980, K-Ar geochronologyand geologic history of southwesternArizona and adjacent areas, in Jenney, J.P., and Stone, Claudia, eds., Studies inwestern Arizona: Arizona GeologicalSOciety Digest, v. 12, p. 201-260.

Sheppard, R. A., Gude, A. J., 3rd, and Edson,G. M., 1978, Bowie zeolite deposit,COchise and Graham counties, Arizona inSand, L. B., and Mumpton, F. A., eds.,Natural zeolites, occurrence, properties,use: New York, Pergamon Press, p. 319­328.

Silver, L. T., 1978, Precambrian formationsand Precambrian history in COchise county,southeastern Arizona, in Callender, J. F.,and others, eds., Lanctof COchise: NewMexico Geological SOciety Guidebook, 29thField COnference, p. 157-163.

Spencer, J. E., and Reynolds, S. J., 1987,Middle 1ertiary tectonics of Arizona andadjacent areas, in Jenney, J. P., andReynolds, S. J., eds., Geologic evolutionof Arizona: Arizona Geological SOcietyDigest, v. 17 (in press).

Stewart, J. H., Anderson, T. H., Haxel, G. B.,Silver, L. T., and Wright, J. E., 1986,Late Triassic paleogeography of thesouthern COrdillera; the problem of asource for voluminous volcanic detritus inthe Chinle formation of the COlorado Pla­teau: Geology, vol. 14, no. 7, p. 567­570.

Titley, S. R., ed., 1982, Advances in geologyof the porphyry copper deposits, south­western NJrth America: Tucson, Universityof Arizona Press, 560 p.

'Ibsdal, R. M., Haxel, G. B., and Wright, J.E., 1987, Jurassic geology of the sonoranD9sert region, southern Arizona, southeastcalifornia, and northernmost SOnora: con­struction of a continental-margin magmaticarc, in Jenny, J. P., and Reynolds, S. J.,eds.;-Geologic evolution of Arizona:Arizona Geological SOCiety Digest, v. 17.,(in press).

Wardlaw, B. R., and Harris, A. G., 1984,COnodont-based thermal maturation ofPaleozoic rocks in Arizona: AmericanAssociation of Petroleum Geologists Bul­letin, v. 68, p. 1101-1106.

Wrucke, C. T., otton, J. K., and D3sborough,G. A., 1986, Summary and origin of themineral commodities in the middle Protero­zoic Apache Group in Central Arizona, inBeatty, Barbara, and Wilkinson, P. A. K.,eds., Frontiers in geology and ore depos­its of Arizona and the SOuthwest: ArizonaGeological SOciety Digest, v. 16, p. 12­17.

Industrial Minerals and Rocks of Arizona

H. W3s1ey PeirceArizona Bureau of G:lology

and Mineral Technology845 N. Park Ave.

Tucson, AZ 85719

mineral world. They are those naturally­occurring, inorganic, nonmetallic-appearingrocks and minerals that enter into commerce.They include the more mundane, everyday rocksand minerals of the earth - the sands,gravels, limestones, clays, salts, cinders,etc., that usually do not figure in "get-rich­quick" schemes. Someone, however, has todiscover and develop these natural materialsif we are to have the conveniences (houses,roads, etc.) that are the hallmark of moderrlcivilization. Most of us are users, not pro­ducers, and we know little about the blood,sweat, tears, knowledge, imagination, risk,patience and investment that lie behind theeveryday things that we all use, but take forgranted. OVer the long haul it would appearunwise to lose sight of the basic supfOrts ofmodern life, which include essential indus­trial minerals and rocks.

As is often emphasized, Arizona can besubdivided into three contrasting geologie­physiographic provinces or regions. These,along with some of their associated industrialminerals (1M), are shown in Figure 1.

As might be expected, Arizona's industrialminerals (1M) industry is strongly influencedby population, industrial growth, and thecondition of the economy. We are the sixthlargest state in area and have been near thetop in fOpulation growth over the past decade.At the same time we are the sixth least fOpu­lated state per square mile.

Figure 2 is an attempt to smw the state'ssteady popUlation gain for the period 1950­1982 as well as the fluctuating, tmlYJh gener­ally rising, production curve for common 1Mmaterials such as sand-gravel, and stone. Theproduction fluctuations, in contrast to thesteadily rising population curve, reflectchanging economic conditions. The gross valuecurve, on the other hand, reflects the effectsof price inflation, especially since about1974. This demonstrates that true growth isbetter represented by production and not valuetrends. Since 1950 there has been a fourfoldincrease in Arizona's population, a concomi­tant twelvefold jump in sand-gravel production(short tons), and a twentyfold jump in "stone"production.

In 1981 Arizona was ranked number one inthe nation with respect to the value ($2.56billion) of nonfuel-mineral production(Burgin, 1983). About 91.8 percent of this

17

ABSTRACT

Arizona embraces portions of two majorwestern-u .S. phys iographic-geologic provincesand a smaller, local one. These exert funda­mental control over the geologic framework andassociated earth-material resources and poten­tial. The Mogollon Rim diagonally crosses theState and separates the Colorado plateau Pro­vince to the northeast from the TransitionZone and Basin and Range Province to thesouthwest. More than 90 percent of the fOpula-

production of nonfuel minerals, agricul­tural land, and water resources are in theBasin and Range part of the State.

In 1981 Arizona was ranked number one inthe Nation with respect to the value ($2.56billion) of nonfuel-mineral production. About8.2 percent of this amount ($212.9 million)can be attributed to nonmetallic (industrial)

Although a diversity of non­substances is produced and some are

exported, the bulk is utilized within theand is directly related to market

(Jrl~w·th. Since 1950 there has been a fourfoldin Arizona's population, a concomi-

twelvefold jump in sand-gravel productiontons), and a twentyfold increase in "stone"

New industries developed duringtime inclu:1e cement, salt (and storage of

petroleum gas products in solutionities in salt), zeolite, hydrofrac sand,

clay pipe, crushed marble productsfeed additive, pool sand, roofing granules,

.), and "rock" wool. Most of these newerserve out-of-State as well as in­

markets. In 1981 at least 225 indus­mineral or rock deposits were being

",n,rk'",rl to produce about 1 0 tons of materialArizona resident per year. In 1980 the

Ll;;j_Lcn;.lVl;;j values of basic industrial mineralsin the state, by major group, were

and lime (51.6 percent)i gravel (26.5pe:r-cl:m1tli sand (l1.8 percent)i stone (4.6pel~cent)i and others (5.5 percent).

Detailed knowledge of the nonmetalliccontent of most Arizona

and basins is lacking. ExplorationoPPJ:r-tlJn:iLLes in this sun-belt growth regionappear encourag ing.

INTRODUCTION AND OVERVIEW

Industrial minerals and rocks are theof life, the bread and butter of the

ogy,th­lity

, J.ranlast:an­tticJ .,

na:17.,

B.,186,thef a; in)la-,67':"

iro­in

K.,os­:ana12-

84,of

canul-

Igh,the

187,andand.ionety

.onsrlty,

F.,New19th

;on,Ii t,~ inds.,Les,119-

J .,and.ogy:ern" J.; incal

--

18

:WiI\

I ~/ I-~ ~

\ i L~Ir I

330~_J\

.J

LEGEND OTHER SYMBOLSCJ] Exported BENTONITE Plant nearby

@ In-State BENTONITE Crude source only

EJ Exported and In-State BENTONITE Plant distant

CJ Industry Shut Down 0 Unuploited

6 Solution Cavity Storage U Underground

Figure 1. Map of Arizona showing geologic provinces, general locations of major industrial

minerals operations, and some undeveloped deposits.

ITE

100

87.5

(/l

75"-ell

'0'C....062.5(/l

c:0=E 50

w::>...I 37.5or:(>

25

12.5

40

37.5

35

32.5

30

27.5 ~o

25 ==E

22.5-(fJ

20 zo17.5 I-

15

10

7.5

5

1950-1982

Average population increase per year =69,134

Population in 1985 = 3.0 million

Est. population in year 2,000 =4.8 million

2.75

J....oo•••••2.5

-ot>.

'.

2.25

2.0(/l

c:1.75

0-E

1.5 z0

1.25 ~...I::::la.

1.0 0a.

.75

.50

.25

Figure 2. Graph showing growth in Arizona population, production (tons) of sand-gravel andstone, and combined value of these groups, by year, for the period 1950-1982.

only

rial.

value is attributed to metals, especiallyThe remaining 8.2 percent ($212.9

ion) is credi ted to the nonmetallics. Itbe pointed out, however, that dollar

is not always a valid measure of basicuS1etlJlrle::,s or need. It is axiomatic that thenece,ss:it:iEls of 1 ife tend to be low cost (air,

, food, construction materials, etc.).Figure 3 is an attempt to illustrate bothproduction and value aspects of the major

groups for the year 1980. As an example,sand and gravel made up over 81 per­

of the weight and 38 percent of the• On the other hand, the weight of com­cement and lime was about 6 percent of

total whereas this group made up over 51percenlt of the value. Also shown are some

statistics includirYJ a per~year

of over eleven tons of 1M perzona resident. The value assigned to the

1M production for 1980 ($192.5 million)eg:ua,t€!s to about $71.3 per person, or, $6.42

ton.

19

PRINCIPLES AND HIGHLIGHTS

General Statement

In Arizona, 1M affairs have taken a back­seat relative to the metals, especiallycopper. As a consequence, 1M related activi­ties tend to be carried on quietly and withoutfanfare. With this in mind the remainder ofthis paper will be devoted to some generalprinciples and examples regarding the develop­ment of 1M deposits in Arizona.

Raw Materials SUpply and Planning

Supplying the raw-material needs for alarge and growing community, such as Phoenix,is an orYJoirYJ, dynamic, everyday process thatis completely understood by no one person.'!hat there should be a diversity of opportun­ities, misunderstandings, and conflicts incarryirYJ out this complex process seems inevi­table. While most citizens accept the end-use

·.JIIII

200192.5

175

150 -I/)I:0

125 .-E-

100 ena::«...J...J

75 0C

50

25

0

by weight and value of major

more diverse the geologic character of aregion the more likely will there be occur­rences of useful materials capable of contri­buting to the fulfillment of local and/or moredistant needs. Where geologic diversity per­tains, as it does in Arizona, recognition(discovery) of the existence, nature, or util­ity of a naturally occuring substance may besubstantially delayed (there is always more tolearn). one reason for delayed recognition isburial. Even surface occurrences can, fortechnical reasons, escape detection, accuratecharacterization, and evaluation. There is,for instance, an evolutionary aspect to use­fulness in that needs change or accrue inresponse to increasing technological varietyand sophistication.

Subsurface discovery can be either acci­dental or a consequence of deliberate explora­tion for the substance sought. 'Ihe discoveryof the Luke Salt Body near Phoenix is anexample of the latter. In this case a marketsurvey had indicated that salt was beingimpo~;'rd into Arizona in quantities that, ifproduced locally, could support an operation.A search began and, in 1968, a salt body waspenetrated at 880 feet below a cotton fieldwest of Phoenix near Luke Air Force Base.

20

Population =2.7 million

MISC. STATISTICS

Tons/person = 11.1

Value/person = $ 71.3

Total value= $192.5 million

Total production = 30 million short tons

enl-enoa.LLJC

oZ Av. value total production /ton = $ 6.42

­I/)Q)

I/)I:o­~Ii;;;;;

o~I/)

Figure 3. Illustration showing production of Arizona nonmetals,groups, for the year 1980, and miscellaneous information.

of the earth's crust consists ofand minerals that are nonmetallic in

Whether any of these earthbe subject to eventual exploi­

.... '-'"....... .I.V" of many variables. The

Discovery an::l Recognition

benefits of mineral and energy resourcesdevelopment, they do not, quite naturally,want the in-between procedures to signifi­cantly intrude upon their daily lives. Havingone's cake and eating it too seems an aproposdescription. It is, however, possible tohave it this way as long as we are willing to(1) pay the price ($), and (2) allow the rawmaterials to be sought, foun::l, an::l developed.The latter aspect, however, is becomingincreasingly difficult. Much emphasis isbeing placed on community planning. W}seplanning, it would seem, should include con­sideration of all imj;Drtant aspects of commun­ity life. One of the more difficult tasks isgiving serious, long-range consideration tothe ongoing nourishment that is essential tothe maintenance and growth of a viable commun­ity through an uninterrupted flow of essentialraw materials at a reasonable cost.

­IIIc::o

E-(J)IX:«...J...Joo

major

of a)ccur­ontri­l:" more'{ per­Iitionutil­

lay be)re tolon is, for~urate

~e is,I use­ue inlriety

acci­Ilora­overy.s anarket)eingt, ifItion.r was:ield3ase.

This relatively new industry continues toexpand and fluorish (Figure 1, See Grott ­this volume).

An example of a surface occurrence, thecharacteristics of which went unrecognizeduntil 1959, is the Bowie chabazite depcsit insoutheastern Arizona (Figure 1). Chabazite isa zeolite mineral that is processed to make ahigh-value, molecular sieve product. Thisdepcsit had its geological beginnings in a Mt.st. Helens-type ash fall that was subsequentlyaltered to zeolite by chemical processesattendant to a saline-lake environment. Theconstituent minerals can be identified only inthe laboratory by sophisticated X-ray and SEMtechniques. Prior to the recognition of itsspecific mineral content, this material, be­cause of its light weight and ease of shapinghad been used as a local building stone. Thetrue nature of this depcsit was discovered asa result of an exploration effort to inventoryand characterize natural occurrences of zeo­lite in the west. This interest in naturalzeolites was stimulated by technologicaldevelopments in the use of molecular sieves.Since 1962 the Bowie chabazite deposit hasyielded the most mined tonnage of any naturalzeolite deposit in the united states. About12,000 tons of crude chabazite, valued atabout $30 million in its processed form, hasbeen produced. All production of crude isshipped out of state for final processing anduse.

Relative Value and "Commonness"

1M consti tute a group of earth materialshaving a wide range in value and use. Sandand gravel, usually considered to be "common",might sell for $3.00 per ton whereas lesscommon zeolite, such as the Bowie chabazite,might be worth almost one thousand times asmuch in its processed form. The higher volume- lower cost materials tend to be used locallywhereas the lower volume - higher cost prod­ucts often are expcrted to serve a specializedmarket. Whereas the former tend to be soughtafter and developed as close to a center ofconsumption as possible, the search area forthe latter is much less influenced by marketlocation.

"Commonness" is relative. Sand andgravel, though common around the Phoenixregion, could not satisfy the rigid specifica­tions for concrete aggregate at the Palo VerdeNuclear generating plant. Gravel for concreteuse was hauled from higher-quality (lowvolcanic content) deposits near the ColoradoRiver to the west. Clay for brick making isusually considered to be common because brickis a common product. When used as a buildingstone, however, the Bowie zeolite was also"common". In terms of its present use, it isnot. The most impcrtant contributor to brick­making in Ari zona is the Pantano clay

21

southeast of Tucson (Figure 1). Thismaterial, in addition to supplying Tucson, istrucked to Phoenix where it is blended withmaterial from local deposits to make redbrick. It is also a source of alumina in themanufacture of portland cement near Tucson.Al though it could be said that these arecommon uses this clay-shale is uncommon inArizona. It may prove to be sui table forselected, less common, ceramic uses. Timewill telL

Locations of Raw Materialsand Processing Plants

Most nonmetallic minerals and rocks under­go some type of processing, somewhere. Incertain cases the processing is done close tothe deposi t and in others the raw materialsare delivered to plants either in or out ofArizona. One of the newer 1M - based indus­tries in the State is the manufacture ofvitrified-clay pipe near Phoenix. Althoughthe Phoenix market area is tundamental, pipeis also shipped into Nevada, Utah, New Mexico,and California. In this case, raw materialsfrom three widely separated sources aretrucked to the Phoenix-area plant (the twovi trified pipe clay sources are shown onFigure 1). Much effort and trial and errortesting were given to the recognition, acqui­sition, and development of natural materialscapable of making an acceptable raw-materialsmix (Morris - this volume).

In 1980 over half of the value of indus­trial mineral and rock products produced inArizona is attributed to combined cement andlime ($100 million). There are two cementplants and two lime plants making commercialproducts (Figure 1). In this case, in con­trast to the vitrified-clay pipe plant, eachplant is located near large reserves of theprincipal raw materials requirement, lime­stone. Because no suitable limestone depcsitsoccur in the Phoenix region (Maricopa County),the products derived therefrom must be trans­pcrted from outlying regions if there is to becontinued maintenance and growth.

Conflicts

Inevitably, in the attempt to supply raw­material requirements, there are impactsassociated with production, processing, andtransport ion. These include the unavoidabletrade-offs that are usually considered to beenvironmentally negative. A typical reactionis to suggest, as if location were completelyarbitrary, that a particular operation be doneelsewhere. "Why here?" is always a goodquestion and "because" is usually an unsatis­factory answer.

One example of a locational conflictderives from the fact that there are abundantcinder depcsits near Flagstaff (Figure 1) and

IJ

none in the Phoenix region (See Welty andSpencer-this volume). A variety of construc­tion blocks is made in Phoenix for the localmarket. one, called cinder block, uses someFlagstaff area red cinders. A competitor,wanting to develop an alternative cinder blockfor arahi tects, dec ided to use black cindersif he could find an available deposit. Thesearch led him to the very fringes of the SanFrancisco Volcanic Field, 20-25 miles north­east of Flagstaff, where he found a deposit ofblack cinders on private land. This parti­cular deposit happened to be adjacent toMerriam Crater, a place where the lunar astro­nauts trained. A rumor began to circulate tothe effect that someone was going to mine thisvery special cinder cone! The subject wasplaced on the agenda of a regular meeting ofthe Governor's Commission on Arizona Environ­ment to be held at Flagstaff.

The thrust of the presentation was thatsomething was wrong when a person could justcome in and mine "common" cinders anywhere!Why open a new pit when there were so manyothers already in existence? Obviously, therehad to be some kind of local control to over­see this type of uncalled-for development. Upto this point, cinders had been treatedgenerically - they were all the same. Fromthe floor, a representative of the U.S. Bureauof Mines asked if the presenter had talkedwith the pit owner to see what he had in mind?The answer was negative. The USBM person thenasked what the cinder color was in all ofthese existing cinder pits? "Red" was theresponse. Well, the interloper from Phoenixwanted black cinders. Could the presentertell us where to find black cinders andcomment on how common they might be? Jlqain, anegative response. The point was made thatthe cinder seeker from Phoenix was not asirresponsible as casual observers and criticshad made him out to be.

Those whose task it is to find mineral andenergy resources, especially those resourcesthat are buried and not directly observable,are understandably concerned about land clas­sifications that stymie the search. It wouldseem as though the ultimate user of materials,the general public, also has a vested interestin maximizing opportunities for search anddiscovery. We hear the expression "specialinterests" with regularity. with regard tothe seekers of mineral and energy resources,they could not function if there wasn't alarger "general interest" to be served.

An example of the surface-subsurfacedichotomy is the position of the earlier esta­blished Petrified Forest National Park withrespect to subsurface resources of potashdiscovered later. The Park is above a portionof the Holbrook evaporite basin. The initialMonument was created in 1906, the first saltencountered by drilling in about 1920, and theassociated potash (KCL) suspected in 1951, was

22

confirmed by drilling in 1964. This 1964confirmation initiated an intensive search foreconomic deposits of potash (Figure 1). Morethan 100 holes were drilled, many of whichencountered potash (Peirce and Scurlock,1972). Potash was found on two sides of thePark therefore it is believed to be continuousbeneath it (Peirce, 1969). IEposits judged tobe economic have not been outlined thereforethey are classed as potential resources ofpossible future interest. There is no intenthere to in any way downplay the fabulous Park.Rather, these comments are presented merely asa case history that illustrates the difficultyin knowing, at any given time and place, whatsecrets the earth holds beneath its surface.

Market Stability

Markets for IM vary acco~ding to the com­modity, economic conditions, and competitivedevelofIllents.

An example of production longevity is thespecial bentonite clay that occurs in southernApache county in the plateau province ofnortheastern Arizona (Figure 1). This clayhas, it is believed, been in continuous prod­uction since 1925. Like the Bowie zeolite, itis an alteration product of vitric ash. Theraw clay is stripped of its overburden andshipped out of state for processing into des­iccants, thickeners, and acid-activated clayproducts (See Eyde and Eyde - this volume).

OVer sixty years ago Arizona led the na­tion in the production of chrysotile asbestos.Its low iron content made it especially valu­able for certain electrical applications(covering cables, etc.). Until recently, itwas in almost continuous production, an esti­mated 160 deposits supplying the demandthrough the years. lbday, for liability (notscientific) reasons, the industry is inoper­ative in Arizona (Peirce, 1983; See Ross ­this vol ume) •

There is a group of IM that have beensporadically produced. These include barite,fluorite, diatomite, feldspar, quartz, mica,etc. For the most part these, in relativelysmall quanti ties, have been exported for useelsewhere as oonditions permitted.

THE. FUTURE

Arizona, like a magnet, attracts people.Population growth seems inevitable, as doesthe industrial growth that must occur ifpeople are to find employment. Whether or notthere will be significant expansion in basicIM industries depends upon growth rate.Arizona has the potential for development ofadditional IM deposits through new discoveriesand changes in circumstances that ·affectdevelopment of deposits already known.

Because of geologic variety and complex­ity, Arizona's major mineral production and

s 1964~ch for

Morewhich

rlock,of the:inuous[ged to~refore

ces ofintent

5 Park.:elyas:iculty, whatface.

,e com­~titive

is the>Uthernlce ofs clay

prod­,te, ith. Theen ando des­j clayne).he na­)estos., valu­'ltionsly, itesti­

emandy (not10per­~oss -

~ beenarite,mica,

civelyor use

eople.s does:ur ifor notbasicrate.

ent ofveriesl.ffect

lplex­)n and

development potential seem vested in thesouthwestern half of the state - the Basin andRange geologic province. Many geologicmysteries remain and inherent in these aremineral resource discovery opportunities. 0p­portunities must be identified if the stateand nation are to continue to be supplied withthe basic ingredients that have come to be thefoundation of modern civilization (SeeReynolds and Fe irce - this volume).

REFERENCES CITED

Burgin, L. B., 1983, The mineral industry ofArizona: in u.s. Bureau of Mines,Minerals Yearbook, Centennial edition,1981, voL 2, Area Reports - Domestic, p.55-73., T. H., 1978, Bowie zeolite - An indus­trial mineral: Bureau of Geology andMineral Technology Fieldnotes, v. 8, no.4, 5p.

irce, H. W., 1969, Salines: in Mineral andwater resources of Arizona, Arizona Bureauof Mines, bulletin no. 180, p. 417-424.

..._.______ 1983, Asbestos - Toward a perspec-tive: Bureau of Geology and Mineral Tech­nology, Fieldnotes, v. 13, no. 1, 8 p.

irce, H. W., and Scurlock, J.R., 1972,Arizona well information: Arizona Bureauof Mines, bulletin no. 185, 195 p.

23

er­'ley

ofLIe~at

mdmd~.of

ar-

The Geology of Cement Raw Materials:Pacific Southwest

S. A. Kupfennansenior GeolCX]ist

Kaiser Cement Cbrp.Pennanente, CA 95014

LS­LonW.,LS-~o­

l6,

~ls

Le:73,

ofley

~st

<e:'ey

.umlr-

~e,

)ve

m:

m:

lrdn,

'0-

ABSTRACT

Cement raw materials used in southerncalifornia and Arizona cement plants occur ina wide variety of geologic environments.Limestone, the primary material making up 75­80% of the raw materials mix used in cementmanufacture, is mined solely from PaleozoicEr"a deposits. DJring this time, 570-245 mil­lion years ago, vastly more limestone wasformed in California and Arizona than at anyother time (continent was in southern lati­tudes) •

The general geology of each limestonedeposit associated with the eight southerncalifornia and two Arizona cement plants willbe reviewed. Many of these deposits are geo­logically complex, having been subjected toMesozoic deformation, metamorphism and instru­sive events, along with Cenozoic uplift anddefonnation.

All of the cement plants in this regionrequire the use of secondary additives inorder to meet the chemical requirements forcement. The kinds of additives vary greatly,depending upon the chemistry of the limestonedeposit, cement specifications, and the cementmanufacturing process. In some cases, claydeposi ts with sui table chemistry on or nearthe limestone sources are utilized. Wherealkali limi tat ions or need for alumina-richmaterials exist, then specialty clay depositsare used. Iron-rich sources in the regioninclude iron ore deposits and slag or millscale from local steel mills. The geologicsetting and location of these additives, alongwith gypsum and silica-rich deposits presentlyin use, will be mentioned.

INTRODUCTION

An understanding of both regional andlocal geologic habi t of cement raw materialdeposits is not only essential for explorationof undeveloped deposits, but where complexityexists, also during development and productionfor purposes of quality, cost and long-rangemine planning.

Cement raw materials utilized in southerncalifornia and Arizona cement plants are wide­ly distributed geographically and occur in avariety of geological environments. Lime­stone, the primary material making up 75-80percent of the raw materials mix for cement

37

manufacture, is mined solely from PaleozoicEra deposits in this region. Many of thesedeposits are geolCX]ically complex, having beensubjected to Mesozoic deformation, metamorphicand intrusive events, along with Cenozoicuplift and deformation. The remaining 20-25percent of the mix, which consists of addi­tives such as silica, alumina, gypsum, andiron-oxide-containing materials, occurs eitherin the limestone, in separate deposits ofdiverse ages, or as man-made waste materials.

The information presented here is basedupon both published and unpublished sources.It is common industry practice to treat de­tails as proprietary thus this presentation isonly a general overview of the subject.

There are eight cement manufacturingfacilities in southern California and two inArizona. 'Ibtal annual cement production capa­city for southern California is 8,200,000tons, and for Arizona is 1,750,000 tons, atotal of 9,950,000 tons of annual cement plantcapacity (pit and Quarry data). In 1984,portland cement shipments, by destination,were 5,552,400 tons for southern Californiaand 1,821,300 tons for Arizona, totaling7,373,700 tons for the region (U.S. Bureau ofMines data). Of this total, about 15 percent,or about 1,100,000 tons, was imported throughthe Nogales, Arizona, San Diego, and IDsAngeles ports of entry. If the imported quan­tity is subtracted from the total shipments,it is estimated that about 6,270,000 tons ofcement, representing about 63 percent of capa­city, (Table 1) were produced within theregion.

'Ib provide an idea of the quantities oflimestone and additives required for thisproduction, the following assumptions aremade: (1) it takes about 1.50-1.75 tons of rawmaterial to make 1 ton of cement, and (2) 80percent of the raw material feed mix is lime­stone and 20 percent is substances containingsilica, alumina, sulfate, and iron. Thisresults, based on the 1.75 factor, in theannual utilization of 10,972,000 tons of rawmaterial feed of which 8,777,600 tons is lime­stone and 2,194,400 tons is additives.

Portland cement is a standardized prod­uct, the standards being based upon criteriadeveloped by the American society of Testingand Materials (ASTM). Specifications includechemical composition, physical performance,and fineness of the cement. Regarding chemis-

ck.(2)ica(1)~k,

1S­

1e,te,~t.

~ed

mdler:edLngLngtc.mtLnglis~aw

Lng~rn

ao-lentlyes.~rn

as

>mi.

s.

90palastiteof

oro Grande and the Black Mountain-SidewinderMountain areas located 16 miles east-northeastof victorville. These limestone dep:>sits havesupplied the IDs An;]eles area market for morethan 100 years and presently support two ce­ment plants, SOuthwestern's Black Mountainplant and Gifford-Hill's Oro Gr"ande plant.

The limestone deposits occur in large,moderately to severely metamorphosed roofpendants more or less surrounded by graniticrocks. In the late Paleozoic (?) Oro Grandeseries, utilized by Gifford-Hill at ODJ Grandeand by s::>uthwestern at Black Mountain, crys­talline limestones are interbedded with thickunits of quartzite and mica schist. The car­bonate units are commonly several hundred feetthick and several thousand feet in exposedlerqth. The limestones are medium to coarsegrained and vary from white to dark blue-gray.The regional trend of these deposits in thearea north of Victorville is northwest and iscut by east-trending cross faults. Thisnorthwest trend is further disrupted by

,smaller strike and transverse faults and bytight, usually ruptured minor folds. Graniticintrusions cut the metasedimentary section andincrease the complexity. The Oro Grandeseries has been subjected to at least twomajor episodes of deformation that includedregional metamorphism. In all dep:>sits, lime­stones have become marbles, pelites micaschists, and sandstones and cherts quartzites.Cbntact metamp:>rphism has, in some instances,produced high grade metamorphic mineral assem­blages. Recent evidence suggests that thissedimentary sequence is part of a strati­graphic section that correlates with Paleozoicmarine sedimentary rocks of the southern GreatBasin.

Thought to be a part of the Oro Grandesequence, the Permian Fairview Valley Forma­tion is another source of limestone for cementin this district. At SOuthwestern's BlackMountain deposi t, the area is underlain by a1,350 foot thick limestone corqlomerate memberof this formation. The limestone occupies theaxial part of a tightly folded, symmetricalnorthwest trending syncline. Cbbbles, boul­ders and pebbles of dark gray, pinkish grayand black limestone, with minor white to graydolomitic limestone cobbles and pebbles,COmprise more than 95 percent of the clasts inthe corqlomerate. Clasts of brown chert makeup the remainder of the clastic fraction. Thematrix consists of fine-grained light to darkgray limestone with local siliceous and hydro­thermally altered patches. The clasts aregenerally subrounded to well-rounded but occa­sionally angular to subangular. Bedding isill-defined except where the conglomerateinterfingers with a hornfels unit. The Fair­view Valley Formation lies unconformably onmassively bedded limestone and quartzites ofthe Oro Gr"ande sequence and has been intrldedand overlapped by volcanic rocks of the

39

Triassic (?) Sidewinder volcanic series. Thelimestone conglomerate, although not a purelimestone, is sufficiently uniform in chemicalcomposi tion to be usable in cement manufac­ture. Silica content is the primary variableand depends upon proportions of chert clastsand interstitial silicification.

Riverside-Cblton District

The limestone dep:>si ts closest to the IDsAn;]eles market area presently being used forcement manufacture are those of the easternJurupa Mountains located between the cities ofRiverside and san Bernardino. 'Ihese dep:>sitssupp:>rt California Portland Cement Company's(a division of Calmat) Colton plant, locatedabout 5 miles southwest of San Bernardino aswell as Gifford Hill's Crestmore plant about 3miles northwest of Riverside. The limestoneis exposed in a group of hills and occurs asroof pendants in grani tic rock. Some inter­bedding with dolomite and mica schist occurs.

The Slover Mountain deposit, locatedadjacent to California Ibrtland's Coltonplant, is part of a roof pendant of Paleozoic(?) crystalline limestone in granodiorite.The limestone varies from a high grade (99%CaC03 ) coarse crystalline whi te variety to afiner grained blue-gray to white variety witha lesser percentage of caco3• Small, butminor disseminated flakes of graphite arewidespread. Small, contorted lenses of micaschist also exist throughout. Limestonestrata are obscure, trending north-northeastand dipping to the east. The northwesternpart of the dep:>sit is cut by dikes of aplite,pegmatite and granodiorite varying from a fewinches to more than six feet in width.

At Gifford-Hill's Crestmore operation,limestone is mined underground from two lime­stone units, a lower 400-foot thick ChinoFormation and an upper Sky Blue Formation morethan 500 feet thick. The Crestmore operationproduces~theonly whi te cement in the regionand rock from either limestone unit is suit­able for its manufacture. The limestone iscoarsely crystalline and white to blue-gray.The limestone units are separated by gneissichornfelses and schists that have been largelydisplaced by a sill-like mass of quartzdiorite. These deposits, as exposed inoriginal surface quarries, because of theoccurrence of a great variety of exoticcontact-metamorphic minerals, have receivedmuch attention in the past.

'Iehachapi Mountains, Kern District

This area, approximately 60-70 milesnorth of los Angeles, supports three cementplants: California Portland's Mojave plant,Monoli th' s plant near 'Iehachapi, and GeneralIbrtland's Lebec plant. The extensive carbon­ate dep:>sits in this district occur either as

MONOLITH

A ACAL.PORTLAND- MOJAVE

~BarstowA GENERAL PDRTLAND­

LEBEC

Victorville - oro ~ande District

The Victorville area is located' about 90miles N.E. of Los Angeles. The principalexploited deposits are in the hills just eastof the city of Victorville, the QuartziteMountain am Sparkule Hill vicinities east of

Figure 1. Southern Cal ifornia cement plants.

GIFFORD-HILL A ASOUTHWESTERNORO GRANDE "* BLACK MTN

Victorville "KAISER _ C~SHENBURYLOB Anoelea san;frnardino

..z:FtttFFDRD _HIL~~~;;:~:TLAND - COLTON

CRESTMORE

o 20 40mi.=

clay or intermediate igneous or volcanic rock.A three component mix: (1) limestone, (2)clay, igneous or volcanic rock, and (3) silica(quartz, sand). A four component mix: (1)limestone, (2) clay, igneous or volcanic rock,(3) silica, and (4) high-iron ore or indus­trial by-product: or (1) siliceous limestone,(2) clay, (3) high alumina clay or bauxite,and (4) iron ore or industrial by-product.The variety of components needed in a raw feedmix directly relates to the chemistry andgeology of a given 1 imestone deposi t. Otherdeposit considerations include costs relatedto location, reserves, materials handlingcharacteristics, plant design and operatingpractices of plant operations personnel etc.The use of coal as a primary fuel in cementmanufacture provides coal ash with varingproportions of Si02 , A1203 , and Fe203. Thisadds further complexity when evaluating a rawfeed mix.

LIMESTONE UTILIZATION

The limestone deposits presently beingexploited for cement manufacture in southernCalifornia am Arizona occur solely in Paleo­zoic Era formations. During this time, whenthe landmass was in equatorial regions, vastlymore limestone was formed than at other times.

The limestone formations in southernCalifornia used for cement are discussed asdistricts, and located on Figure 1.

38

1,821,300

7,373,700

6,273,700

1,750,000

5,552,400

9,950,000

8,200,000

(1,100,000)

'IOI'AL

Ibmestic total

CEMENT SHIPMENTS

Fbreign share

PRODUCTION CAPACITY

Arizona

Southern california

Southern california

try, the ord inary "commerc ial" or STM Type Icement in this region has the followin;J typi­cal broad composition: CaO (60-67%), Si02(19-24%), A1 203 (4-9%), Fe203 (1.6-6%), MgO(not more than 5%), S03 (up to 3%), K20 + Na20(.65%). Special purpose cements are morestringent in their chemical requirements.Well-known deleterious in;Jredients, when pres­ent in excess, include MgO, S03' alkalies (K20and Na20) , and phosphorous. with the adventof the dry process, preheater precalcinercement plant, volatile compounds such aschlorides, fluorides and sulfur also are con­sidered deleterious to the cement process,thus the existence and/or distribution ofthese components in the various deposits mustalso be determined and evaluated.

The raw materials in cement manufactureare combined in the proper proportions, groundto a fine powder in the dry process, thenheated, first to calcination, then to fusion,in a rotary kiln. The in;Jredients combine toform desired crystalline or glassy substancesand a "clinker" is produced. Clinker, whenfine ground with 3 to 5% gypsum to controlsettin;J time, is portland cement.

The cement company geologist, thus, isconcerned with a 1 ime (CaO) source that, inthis region, is provided by limestones. Thealuminum silicates, iron aluminum silicatesand silica, occur as clays or shales, quartzand quartz sands, feldspars, iron oxides andhydroxide, and combinations of these as ig­neous or metamorphic rocks. The deleteriouselements of each is also considered. Thesimplest raw material feed mix would be asingle rock unit such as a shaley limestonehavin;J all of the proper components. This, anatural cement rock, is not known to exist inthe region. A two component raw feed mixwould be: (1) limestone, and (2) iron-bearing

Arizona

Tab1.e 1. Cement data (tons) for 1984 ­southern California and Arizona (sources: Pitand Quarry; u.s. Bureau of Mines)

roof pendants or as elongate layers partlyencased in younger intrusives varying fromvery basic to highly silicic. The limestonedeposits occur either alone or interbeddedwi th mica schist and quartzite in sequencesreferred to as either the Bean Canyon forma­tion or the Kernville S3ries. In the absenceof fossils these units are considered to belate Paleozoic or early Mesozoic in age. '!helimestone is commonly coarse grained withcolors ranging from white to blue-gray. D::>lo­mi te and dolomitic limestone is present in theform of isolated PJckets and/or massive inter­beds. smaller granitic intrusions are commonwithin individual limestone bodies and silicaand silicate minerals produced by contactmetamorphism add to the complexity of thesedePJsits.

OJshenbury District

Limestone dePJsits in this area, locatedapproximately 25 miles southwest of victor­ville, are utilized at Kaiser Cemen~s Cushen­bury plant. '!he OJshenbury limestone dePJsi tis part of a large roof pendant of upperPrecambrian to upper Paleozoic metasedimentaryrocks uplifted and exposed along the northflank of the san Bernardino Mountains duringlate Cenozoic time. The deposit containslimestone and dolomites of Mississippian andPennsylvanian ages. The limestone is locallyreferred to as the Furance formation, however,typical Great-Basin stratigraphic nomenclatureis currently being considered for this pre­Mesozoic carbonate sequence. The carbonaterocks have generally been regionally metamor­phosed. Moderately high grade metamorphicfacies with local increases in grade and char­acter of metamorphism occur adjacent to intru­sive dikes, sills and stocks of aplite, grano­diorite and biotite quartz monzonite. Thelimestone produced from the quarry is typical­ly recrystallized, medium to coarse grainedcalcite marbles of varying purity. Eventhough these carbonate rocks have been recrys­tallized from limestones to marbles, theoriginal sedimentary structures have beenretained in many of the individual rock units.Surface mapping has resulted in the identifi­cation of at least 16 different limestoneunits, with differentiation based upon chemi­cal composition, color, crystal size andstratigraphic PJsition. '!he effects of meta­morphism and intrusion on the original chemi­cal cOInPJsition resulted in the replacement oforiginal carbonate with varying amounts ofiron, silica, aluminum and alkali-bearingminerals.

'!he dePJsit is located at the junction of .the northwest trending Helendale right lateralstrike-slip fault, and the east-west trendingFurnace reserve (thrust) fault. The thrustfault zone is exposed as a series of claylayers one to two feet thick and two to three

40

feet apart, in a zone 20 to 40 feet thick.Two other fault systems have been identified,high angle, east-west trending reverse faults,and high angle normal faults with east-west tonortheast trends.

Arizona

Two cement plants operate in Arizona:Arizona Bortland's Rillito plant located about18 miles northwest of Tucson, and Gifford­Hill's Clarkdale plant in the central part ofthe State approximately 95 miles north ofPhoenix. These operations are located onFigure 2. Limestones utilized at these plantsare from Paleozoic carbonate units containinglimestone, dolomite, and chert along withmegafossils indicative of shallow, clear,marine environments of dePJsition.

ARIZONA

CEMENT PLANTS

~ Flagstaff...GIFFORD- HILLCLARKDALE

:ttf: Phoenix

ARIZONA PORTLANDRILLITO...

#. Tucson

Figure 2. Arizona cement plants.

Arizona Portland's Rillito plant is sup­plied largely with limestone from their TwinPeaks deposit located about 4 miles southeastof the plant. Limestone formations utilizedfor cement include the Levonian Martin Fbnna­tion, Mississippian Escabrosa Limestone andPennsylvanian lbrquilla Limestone.

The lbrquilla Limestone typically consistsof fine grained, light yellowish gray lime­stone interbedded with shaley or silty lime-

8. S:Juthwestern - Black MJuntain Fairview Valley and era Q:'ande1,400,000 tons series

(roof pendant - Basin andRarge)

- plant- plant

- Vail- plant, quartzite- iron ore - California

clay - Fctoniron - Fontana

clay - plant

clayvole.

claysilicairon

shaleclayiron

shale - plantsilica - gold mine tailir:gsiron

unkrown

shaleclay - Coronairon

claysilicairon

Clay

ARIZONA

2. Gifford-Hill - Clarkdale

7. MJnolith - Tehachapi

6. Kaiser cement - Cushenbury

5. Gifford-Hill - oro Graooe

4. Gifford-Hill - Crest

2. California Eortland - Colton

3. General Fbrtland - Lebec

1. Arizona Fbrtland - Rillito

Plant

1. california fbrtland - M:>jave

8. S::mthwestern - Black rvuntain silica - oro Grande series quartziteiron - altered dacite

tions used by each producer in southern cali­fornia am Arizona.

Tab~e 3. Raw materials additives utilized bycement plants - southern California andArizona

SCXJrHERN CALIFORNIA

ADDITIVES

No discussion of cement raw materials iscomplete without mentioning the additivesutilized to provide silica, aluminum am ironto the raw material feed stock, along withgypsum which is added to the cl inker for thefinish grind. The usage of silica, aluminumand iron addi tives is usually based upon thechemistry of the particular limestone, andcement specifications. Approximately 3-5%gypsum is added in order to control or retardthe set time of the final cement product.Rather than discuss each additive source foreach producer in the region, only selecteddeposits will be mentioned. The general typesof additives used by each plant are summariZedin 'IClble 3. The following is a discussion ofselected deposits with locations shown onFigure 3.

The Alberhill-Corona clay deposits,located in the western Riverside Cbunty areaof southern california, about 45 miles south­east of Los Angeles, have provided silica,aluminum, and iron-bearing clays to the cementplants in this region. The clays in thisdistrict are of two origins - resiUual and

41

Stratigraphic Asscx:.., I:epJsitType and/or ProvincialLocation

Chino and Sky B1ue(roof pendant)

M'>rtin and Redwall(outcrop bel t - Transi tion ZOne)

Slover l>buntain(roof pendant)

era Gr"ande 8eries(roof pendant - Basin and Rarge)

Bean canyon/Kernville series(roof pendant)

Bean Canyon/Kernville Eeries(roof pendant)

Furnace(roof pendant - Basin and Rarge)

Eean canyon/Kernville series(roof pendant)

M3.rtin, Escabrosa, and HJrquilla(Fault block - Basin and Farge)

ARIZONA

sourHERN CALIFCRNIA

Plant-Annual cementCapacity

Gifford-Hill - Clarkdale600, 000 tons

Arirona fbrtland - Rillito1,150,000 tons

7. r1)noli th - Tehachapi500,000 tons

2. california lbrtland - Colton750, 000 tons

4. Gifford-Hill - crestmore840,000 ton

(incltrles white canent)

L california lbrtland - M:>jave1,400, 000 tons

3. General RJrtland - Lebec610,000 tons

6. Kaiser cement - CUshenbury1,600,000 tons

5. Gifford-Hill - oro Grande1,100,000 tons

2. Limestone-bearing formations uti­ized by cement plants - southern california

Arizona

stone. Thin beds of siltstone, shale, andchert are also scattered through the forma­tion. The Escabrosa Limestone consists ofwhite to light gray limestone in the upper ammiddle parts and light to dark gray dolomiteand limestone in the lower section. TheMartin Fbrmation consists mostly of very fineto fine grained, laminated to thin bedded ammedium dark gray to olive gray, dolomite.Samstone and shaley 1 imestone beds, h::>wever,are scattered through the formation.

Limestone for Gifford-Hill's Clarkdaleplant comes largely from the MississippianRedwall Limestone. The Redwall Limestone is amassively bedded, often cherty, gray andcoarsely crystalline rock with few impurities.

A common thread that runs through all ofthese deposits is the complexity involved incanprehending rock canposition such that themined rock will (l) meet raw feed specifica­tions, (2) be consistent with day to day rawfeed chemistry and (3) meet long term mine

needs for the deposit. Variations indeposits result from (1) pri­

variations caused during deposition,vertically or laterally, (2) secondary

chemical changes associated with regionaland/or contact metamorphism, and (3) struc­tural activity that causes folding and/orfaul ting typically resulting in repetition ofunits, termination of deposits, radical dif­ferences in dip directions etc.

Table 2 summarizes the limestone forma-

:ona:moutord­·t ofh ofd onLantsiningwith.ear,

sists.ime­lime-

sup­Twin

heastlizednma­e and

lick.Eied,.1lts,;t to

a>me of the cement manufacturers prefer touse iron-rich materials in order to attain therequired iron proportion in the raw materialfeed mix. By far the purest iron-bearingsubstance presently being utilized is "man­made" mill scale or sinter mix from KaisserSteel's (now closed) Fontana Mill near SanBernardino in southern California. Thematerial is + 90% Fe203' with the remainderbein;} Si02 am A1203•

'!he cave Can:iUn iron ore deposit, owned byCalifornia Ibrtlam Cement co. and located 50miles east of Barstow, is typical of an iron­rich material for cement manufacture. The ironminerals, magnetite and hematite with subordi­nate limonite, occur in bodies that areenclosed in a complex of metamorphosed dolo­mi tes, tacti tes and grani tics. In general,the deposits and surrounding units trend east­northeast with intricate faulting, breccia­tion, and simple to complex folding beingCharacteristic. This iron ore deposit isconsidered to be the second largest in oouth­ern California (second to Kaiser Steel's Eagler-buntain deposit) with proven reserves of morethan 10 million tons. Typical ore assaysaverage 90% Fe203' the remainder being Si02am A1 20 3•

In Arizona, Arizona Ibrtland Cement usesquartzi te from the Cambrian Abrigo Fbrmation,

Silica

Gabriel r-buntains approximately 40 miles northof IDs Angeles, near the town of Acton. Thered to yellowish-orange clay results from theweathering of a Precambrian pluton of anortho­site. The anorthosite is an unusual lightgray to white, equigranular, medium to coarsegrained, brittle rock composed essentially ofthe one feldspar mineral, plag ioclase(andesine). '!he clay deposits occur either asresidual or as recent colluvial material ex­posed on upland slopes. A typical analysis ofthis material is: Si02 46%, Fe203 11%, A120335%, and total alkalies 1-1.5%.

In addition to the cited "high" aluminumclays, some producers also use a "common" clayor clay shale, usually located near the cementplant, for a source of silica, alumina andiron. These deposits are either young allu­vial clays or older clay shales that areassociated with the limestone deposits. As anexample, Arizona Ibrtland Cement's Rillitooperation hauls a clay-shale from the 01 igo­cene Pantano Fbrmation that crops out about 20miles ooutheast of Tucoon. A typical analysisis: Si02 53.8%, Al 203 17.6%, Fe203 4.8%, Na20

.0.3%, K20 3.7%, S03 .48%, etc. (personal ?om­munication, Jerry Boyett - Plant ChemIst).'!his source also is widely used in the manu­facture of red brick in both Tucson andEhoenix (a haul distance of about 150 miles).

IRON

42

•FISH CREEK - GYPSUM

TVictorville

4= Barstow

ACTON.ALUM.-CLAY

Los Angel~ Son BernardInoFONTANA• .JlI

IRON• 1rRiverside

CORONA- ALUM.-CLAY

o 20 40mi.b3

• CAVE CANYON-IRON

sedimentary. The residual types have deVel­oped in place by subaerial chemical weatheringof aluminum-rich rocks includin;} quartz latiteporphyry, quartz diorite, volcanic latite andandesite and slates. The sedimentary claysand clay shales utilized are locally part ofthe Paleocene Silverado Fbrmation. '!he forma­tion consists primarily of brown to grayclastics that include cOn;}lomerates, sand­stones, siltstones, and claystones.

. The nonmarine lower member contains largequantities of alumina-rich clay and smallamounts of bauxitic clay. other claymaterials consist of reddish-brown pisoliticsandy clay, a read mottled clay, and a whiteto brownish conchoidally-fracturing kaolinite.Clay beds are 1-10 feet thick, and generallyhave little continuity. Thrust faulting andmul tiple episodes of normal and reversefaul ting resul ted in vertical beds and discon­tinuous clay layers. It is necessary to mineselectively and to blend in order to obtainconsistent quality control.

In addition to supplying clay to cement.plants in oouthern California, the corona claydeposits have principally been a source forthe clay manufacturin;} imustry. The princi­pal reasons for utilizing these deposits forcement have been the relatively high aluminumcontent and low total alkali values. A typi­cal analysis is: Si02 60-65, Al 203 25-30%,Fe

203

5-10% and total alkalies less than 1%.Another alumina-rich clay deposit pres­

ently being used in southern California byKaiser Cement Corp. is located in the San

Figure 3. southern California cement raw­material additives.

lorthThethe

'tho­ightlarseyoflaser as

ex­s of,1 203

inumclayment

andllu-are

IS anlitoigo­It 20ysisNa20~om­

.st) •anu-and

as) •

!r tothe

rialdngnan­sserSanThe

rlder

d byd 50ron­ironIrdi-are

010­

ral,!ast­::ia­eingt isuth­:aglemoresaysSi02

uses:ion,

from areas close to their limestone defX)sit atTWin Peaks. This formation contains inter­bedded mudstone, siltstone, sandstone andquartzite. Cblors range from reddish brown toyellowiSh light gray. The quartzi te is com­rosed of subangular to subrounded quartz pluslesser amounts of feldspar.

Quartzite from the oro Grande series isutilized by Southwestern Portland at theirBlack M:Juntain cement Plant. The quartzi te,quarried from locations close to the limestonequarry, is characteristically massive, andpinki sh whi te to brown in color. Quartzi teuni ts occur as interbeds wi th other units ofthe Oro Grande ser ies, such as 1 imestone,hornfels and schists. Faults often disruptcontinuity.

The use of quartzites is one case wherethe chemistry of a raw materials additive may

satisfactory but not useful for physicalQuartzi tes, for example, are much

than limestones. This can result indifferent sizing during grinding, or,

grinding costs during the raw materialing process. A Bond grindability test

nrr"riilA<: an indication of the fX)wer requiredto grind a material to a desired fineness at a

capacity. '!his test affords a means byquartzites can be selected.

Gypsum

The Fish Creek Mountains gypsum defX)sitsthe largest reserves of this com­

in southern California. These defX)sitslocated in extreme eastern Imperial Cbunty

about 70 mils east of San Diego. The gypsumfrom these defX)si ts is primarily used in

the manufacture of gypsum wallboard, I:Dwever,about 20% of the production from this area isused in cement manufacture and supplies mostsouthern California cement plants. The de­posit, consisting of up to 200 feet of massiverock gypsum, 1 iesat the top of the MioceneSplit Mountain Formation. Anhydrite is pres­ent as erratic lenses in the gypsum whileinterbedded clay occurs near the top andbottom contacts of the defX)si t. Minor impur­ities in the gypsum include varying and randomconcentrations of chloride salts and fine­grained, opaque manganese and iron oxides.The gypsum outcrops as erosional remnants,preserved in a shallow syncl inal basin wi thbedding dipping toward the synclinal axis at15-30 degrees. The suggested origin is rapidevafX)ration in seacoast lagcons with periodic

43

influx of sea water. several parties controlportions of the defX)sit. U.S. Gypsum Cb. ownsthe most significant part and operates thegypsum quarry that provides the majority ofthe Fbrtland Cement gypsum proouction. Cali­fornia Fbrtland cement Cb. holds mining claimsadj acent to U.s.G.' s holdings and intermi t­tently mines the gypsum for use in theirsouthern Cal ifornia cement plants. NationalGypsum controls a large undeveloped depositsouth of Cal ifornia Portl and's holdings.Gypsum for the two Arizona plants comes fromPI iocene defX)si ts located within their respec­tive regions. These defX)sits represent condi­tions of evaporation in local, nonmarinebasins.

SUMMARY AND ACKNOiVIEIG1ENI'S

The geology of limestone defX)sits used forcement manufacture in southern Cal ifornia andArizona is quite complex. The southern Cali­fornia defX)si ts are metasedimentary roofpendants of Paleozoic limestone-bearingstrata. The Arizona deposits, on the otherhand, are of relatively unal tered Paleozoicformations that contain abundant limestones•Along with the usual variable nature of flat­lying limestone defX)sits resul ting from slightlateral changes and layering, the CaliforniadefX)sits have been subjected to Mesozoic de­formation, intrusion and metamorphism, andCenozoic deformation. The use of specificadditives depends UfX)n the chemistry of indi­vidual limestone deposits, cement specifica­tions, costs, and the cement plant operation.Clays and shales provide the majority of iron,silica and aluminum additives to the rawmaterial feedstock. These materials areeither located near or actually associatedwith the limestone defX)sits. AluminUIll richmaterials are sometimes obtained from claydeposi ts rich in aluminum, while iron-richmaterials are obtained from steel mill slagand mill scale stockpiles that are of veryhigh purity or lower purity iron ore defX)sits.High purity silica is used from sel~cted

quartzite defX)sits.I thank Doug MacIver with Southwestern

Fbrtland Cement, John Rains with CaliforniaFbrtland Cement and Steve Greenspan withPacific Clay Prooucts for providing input andcomments. I also acknowledge M. J. Bishop,Manager, Mineral Resources, Kaiser CementCbrp. for his comments and allowing publica­tion of this paper.

Natural Lightweight Aggregates of the Southwest

Lennis P. BryanEngineering Testing Associates

737 Glendale Ave.Sparks, Nevada 89431

ECONC11ICS AND UTILIZATION

In analyzing the economics of using NIAthe prime consideration is transportationcost. Because they occur in the west, they areused in the west. Al though the manufacturedlightweights such as the expandable clays andshales are more evenly distributed throughoutthe United States, because they are energyintensive, cannot compete in areas where NIAis found. Because of fuel costs, many manu­factured-lightweight-aggregate plants closedfollowing the energy crisis of the seventies.'!his led to a renewed interest in western NIA.NIA deposits that haven't been active in yearsare undergoing reevaluation, and previouslyunrecognized natural lightweight rocks arebeing evaluated and developed.

The use of NLA can be traced back to thedays of the lbman Empire when pumice was ex­tensively used in the Mediterranean region.Pumice and volcanic cinder have been utilizedin construction in the western united Statessince near the turn of the century and pumicefrom Greece has been imported on the eastcoast of the U.S. for some time.

'!he principal uses of lightweight aggre­gates are in the construction industry, pri-

the current status and use of these materialsin the southwest.

Lightweight aggregate up to approximatelyone inch in size are utilized primarily in theconstruction industry for weight reduction andinsulation purposes. Pumice and volcaniccinder have long been utilized for these pur­poses, whereas pumiceous rhyolite is a rela- ­tive newcomer.

Other lightweight aggregates utilizedthroughout the country, but not discussed inthis paper, include the manufactured light­we ights such as expanded clay or shale and theul tra lightweights, perlite and vermiculite.EXpanded clays and shales, utilized mostly inthe eastern portion of the country, are manu-

'factured by heating certain clays or shalesuntil they become plastic thus allowing theincluded volatiles to expand. When cooled, theresult is a frothy, lightweight, ceramic-likepellet. Perlite and vermiculite are alsoexpanded by heating but generally result in anultra lightweight material having very littlestructural strength.

55

INTRODUCTION

ABSTRACT

The southwestern United States has anabundance of natural lightweight aggregate(NLA) deposits of volcanic origin that arebeing used in the construction industry withinthe region. New Mexico, Arizona, Nevada andCalifornia utilize NLA in portland cementconcrete and concrete masonry units for weightreduction and related economic reasons.

'!he geological environment of the westernoni ted States is amenable to the occurrence ofnatural lightweight rocks because it containsTertiary and Quaternary volcanic products thatinclude low-density glass and vesicularmaterial. There are two major classical typesof natural lightweight materials of igneousorigin; pumice and cinder. '!hese account forthe vast majority of volcanic rocks that arepresently utilized as NLA. Pumice is anejecta product generally found as part oftuffaceous units associated with nearby sili­ceous volcanic centers. Cinder, also anejecta product, is associated with mafic vol­canics and is most often found as a cindercone. Poth are highly vesicular. A third typeof natural lightweight material, though alsoassociated with siliceous volcanics, is lessvesicular than pumice. It is best describedas being a slightly pumiceous rhyolite orrhyolite-tuff breccia that occurs as a sili­ceous dome or tuff unit that is most likely tobe glassy.

Uses of these natural lightweight rockscenter on the construction industry where theyare utilized in lightweight portland cementconcrete and lightweight concrete masonryunits. '!he major reason for usage in portlandcement concrete is cost saving effected byweight reduction in high-rise construction.The major usage in concrete masonry units, or"block", is for weight reduction that enablesa mason to lay more lock.

Natural lightweight aggregates (NLA) de­scribed here are low density, lightweightvolcanic rocks. '!hey are restricted in theirdistribution to the geologic environment ofthe western oni ted States and consist of pum­ice, volcanic cinder, and pumiceous rhyolite.The purpose of this paper is to briefly review

on,sedernmdica

:ureJQi­jil­.ng,, p.

and.ralia:cts

en­nalernica

l83,leIs1erns a

inj~

JltslIesand

marily in applications for lightweight port­land cement concrete and for lightweight con­crete masonry units.

Portland Qement Cbncrete

In lightweight p:>rtland cement concrete,lightweight aggregates are utilized primarilyfor weight reduction in high-rise construc­tion. A lightweight concrete will weigh ap­proximately 25% less than normal weight con­crete utilizing common aggregates such as sandand gravel. This translates into cost savingsas there is a parallel reduction in the massof footings, structural members and reinforce­ment within the building. A 24-story concretebuilding utilizing lightweight aggregates mayhave the same dead weight as a comparablebuilding 20 stories high utilizing normalweight aggregates.

In addition to weight reduction, light­weight aggregates increase the insulation,thus fire retardation effect, of concrete. Insome cities in the Ebuthwest local codes allowa lightweight aggregate to be utilized not forits weight reduction but for its effectivenessas a fire retarder, thereby reducing floorthickness requirements.

Cbncrete Masonry Units

Cbncrete masonry units, commonly referredto as "block" in the building trades, areaffected by the same properties of lightweightaggregates as is portland cement concrete,namely weight reduction, insulation am fireretardation. In the Southwest where NLA isavailable at relatively low-cost, the mostimp:>rtant use is as a weight reducer in theindividual masonry units. A mason can laymore lightweight blocks during the course of aday than he can heavier blocks made from ordi­nary sand and gravel. This translates intoincreased productivity and related costsavings.

physical and Chemical Properties

As with many imustrial mineral commodi­ties, a thorough evaluation of a p:>tential NIAresource entails an evaluation of how itsphysical and chemical properties affect appli­cation. The imp:>rtant properties of a NIA foruse in portland cement concrete or concretemasonry units include unit weight, specificgravity, absorption, hardness, durability,chemistry (including reactivity potential),cleanliness, expansion characteristics,organic impurities and particle size distribu­tion.

The characteristics of the final light­weight concrete product are highly dependenton these individual aggregate properties. Mostimp:>rtant are the weight am strength charac­teristics of the final product, but other

56

considerations include shrinkage, durability,thermal properties, color, and placement char­acteristics when fresh, such as pumpability.

In some instances processing of the aggre­gate influences its characteristics. Properscreening will determine particle size distri­bution and washing may eliminate undesirableingredients. In most cases, however, indivi­dual properties are inherent in the rock,having been determined by the genetic environ­ment, melt composition, weathering history,etc.

A more complete discussion of individualaggregate properties, etc. is beyom the scopeof this paper. Testing of lightweight aggre­gate, portland cement concrete and concretemasonry units, is outlined in great detail invarious American Society for Testing andMaterials (ASTM) specifications that are up­dated yearly. The American Cbncrete Institute(ACI) publishes standards for the design andevaluation of lightweight portland cementconcrete. Numerous professional and tradepublications of the eng ineering or construc­tion materials professions contain articlesthat deal with imividual properties of bothaggregates and their end products.

GEOr.cx;y AND DESCRIPTION OF THE NATURALLIGHTWEIGHT AGGREGATES

Figure 1 shows the distribution ofTertiary, and younger, volcanic rocks of theEbuthwest. All of the NLA are volcanic inorigin and most are Quaternary or lateTertiary in age. In general, the younger hostrocks yield the higher quality lightweightaggregate because the younger volcanics areusually less indurated or weathered. Also,wi th age comes increasing devitrification ofthe glassy phases, which tems to densify therock.

The method of emplacement or formation ofyoung volcanic rocks suitable for lightweightaggregates must include vesiculation ofaphanitic or glassy material. Goaling of themelt must be rapid and accompanied by volatileexpansion. The composition of the melt alsoinfluences the end-product rock type, be itpumice, volcanic cinder or a close derivativeof either. Silicic lavas give rise to pumiceand pumiceous rhyoli te, whereas mafic lavasyield volcanic cinders. '!he method of emplace­ment usually is pyroclastic, which formstuffs, breccias or cones.

'!he geology of the three most common typesof natural lightweight rocks pumice, volcaniccinder and pumiceous rhyolite is discussed inthe following paragraphs, along with commentson the particular end-product application ofeach aggregate.

Pumice

Pumice is a highly vesicular, glassy vol­canic material, usually white to yellow in

r

e

1e

end

edte

sh

fenette

Figure 1. Distribution of Tertiary and Quaternary volcanic rocks in the Southwest.

E

ECE

)

c

s

s

s:::il

S

E

il

color. It is generally rhyolitic in composi­tion with a silica content near 70 percent.Vesicles are very abundant, usually small, andmay be either spherical or elongated dependingon cooling and consolidation history. sili­ceous magmas have a higher viscosity thanmafic magmas and solidify quickly, resultinJin smaller, more abundant vesicles than inbasaltic volcanic cinder. In general, inexcess of 95 percent of the pumice particlesare glass, with crystal phenocrysts makinJ upthe balance, most commonly quartz, K-feldspar,and bioti te •

Most pumice deposits are formed as tuffa­ceous units, as shown in Figure 2, spatiallyassociated with nearby siliceous volcaniccenters. The pumice may be blown many miles byan explosive eruption with coarser particlessettling closer to the source, while fines,carried by the wind, may sometimes travel vastdistances. Exploitable pumiceous tuff unitscan attain thicknesses measurable in hundredsof feet and cover hundreds of square miles income parts of the world. Particle size distri­bution within most pumiceous tuff units rangefrom ash size to a few inches but occasionallyattain dimensions up to two feet.

Physical characteristics of pumice unitsthat make them desirable for use as light­weight aggregate vary greatly from deposit todeposit and within individual deposits.Younger units are generally less consolidatedand weathered, and therefore yield easilymined and processed, stronger, individualclasts. Particle size distribution is impor-

Figure 2. A pumiceous tuff unit in the BishopTuff, Mono County, california, that was minedin th6 early 1950's.

57

tant because a deposit with excessive finesmay result in excess waste. PrDcessirq of thematerial is simple, consisting of screening,and crushirq of the oversize.

The principal use of pumice in the con­struction industry is for weight reduction inthe manufacture of concrete masonry units. Inthis application, the pumice is confined tocourse aggregate fractions in the size rangefrom 1/2- inch to a i'b.8 sieve si ze. The finerfraction material, sand, is generally notpumice and is usually composed of aggregate ofordinary weight. Coarse pumice, in sizes upto approximately 3/4-inch, is sometimesutilized in portland cement concrete, but, forthe most part, not as the only coarse aggre­gate ingredient. Pumice is the lightest ofthe natural lightweight aggregates. It is,mwever, also the weakest. It is, therefore,usually present as only a fraction of thetotal aggregate required in a concrete mix inorder that the end product will have suffi­cient strerqth.

Volcanic Cinder

Volcanic cinder, sometimes referred to asscoria, lapilli, or just cinder, is a coarselyvesicular mafic volcanic material of sizesgenerally less that a few inches across. Itis basaltic in composition and vitric toaphanitic in texture. Vesicles are abundantand may also be either spherical or elongated,as in pumice. In general, the vesicles incinder are larger than tmse in pumice, some­times attaining dimensions of an inch or more.Like pumice, cinder is a result of rapidcooling of magma containing abundant vola­tiles, but unlike the siliceous magma thatgives rise to pumice, the mafic magma is lessviscous. Magma of basaltic composition flowsreadily and acts more like a typical liquid.Cinder is black to red in color, sometimesacquiring a purplish appearance. Particlesize of clasts in a typical cinder depositranges from ash size to volcanic bombs, oc­casionally attaining dimensions of severalfeet in length.

Volcanic cinder is a pyroclastic rock,erupting from a volcanic vent and, most com­monly, form ing a cinder cone. Cinder conesrange in size from tens of feet to over athousand feet in height. o::casionally, cinderis found as part of composi te cones where itis interlayered with less volatile basic flowsof magma. Well-formed cones are steep sidedand usually reach the angle of repose of thecinder particles. The color of the cinder isrelated to the oxidation state of the.iron inthe parent magma and both red and b}ack areoften found in the same corie. Cinder conesmay be found in isolated occurrences or aspart of large volcanic fields, such as thehundreds of cones found in the vicinity of theSan Francisco volcanic field in northernArizona (see Figure 3).

58

Cinder cones of various ages and degreesof weathering can be found in several loca­tions in the Southwest. Younger cinderdeposits, which are readily distirquishable ascones, generally are the better material foruse as lightweight aggregate. Older, weath­ered deposits, may not be easily identifiableas cones and often contain punky material andclays. Processing of cinder for use as light­weight aggregate is simple, consistirq primar­ily of screening and crushing of the oversize.

Millions of tons of volcanic cinders aremined each year and utilized in the construc­tion industry. Most of the production isdirected to road base material or other typesof construction where weight is not a primaryfactor. Cinder produced strictly for itslightweight properties is used principally inconcrete masonry units. Much of the blockmanufactured in the southwest includes cinderas an ingred ienL••thus the term "cinderblock" is truly applicable. It is used inlightweight portland cement concrete but to alesser extent. Cinder is a much strongeraggregate than pumice and, as in pumice, thefiner size fractions are not generally usedbecause as cinder becomes finer it is lessporous, hence the density increases. Also,cinder fines tend to discolor concrete andconcrete masonry units, a problem in aes­thetics.

Figure 3. One of the largest volcanic cinderoperations in Arizona produces from a Quater­nary cone near Flagstaff.

Pumiceous Rhyolite

The third type of NLA used in the SOuth­west is pumiceous rhyolite. This material isnot ·as well known nor as widely distributed aspUmice or volcanic cinder and is a more recentaddition to natural rocks being utilized aslightweight aggregate. Pumiceous rhyolite,chemically, is nearly identical to pumice inthat it is the product of a siliceous meltwith a silica content in the 70 percent range.Pumiceous rhyolite is also composed of inexcess of 90 percent glass, is similar incolor to pumice, but is much less vesicular.

ed

>, .e

ssyS

r1

kt:"

t:"

r1

:l

r

j

Figure 4. The Mono Craters near Mono Lake arerecent rhyolitic domes that contain pumiceousrhyolite.

Vesicles are much smaller than those of pumicebut usually are well distributed throughoutthe rock. Phenocrysts include quartz, feld­spars and micas. Pumiceous rhyolite depositsare found as (1) domes, and (2) tuff brecciaunits.

Domes, especially those that are young inage such as at Mono Craters (Figure 4), areoften spatially associated with what would beconsidered a classic pumiceous tuff unit. Atypical young dome, as shown in Figure 5, iscomposed of denser rhyolite in the inter lOrwi th progressive envelopes of less densevesicular material surrounding it. pumiceoften mantles the surrounding countryside. Aswith pumice, the melt producir¥J the pumiceousrhyolite was highly viscous. Rhyolite domescontainir¥J pumiceous rhyolite may also containperlite, obsidian or banded rhyolite flows.Here again, as in the pumice and volcaniccinder deposits, the amount of vesiculationand its distribution is governed by the amountof volatiles in the parent melt and its dis­tribution in the eruptive sequence.

Tuff-breccia units consist of individualpieces up to two feet across set in a matrixof ash. Generally, there are no pumiceoustuff units associated with these deposits.

pumiceous rhyolite

The pumiceous rhyolite tuff-breccia unitsevidently were more volatile than those ofdomes, but the individual clasts are verysimilar in that they exhibit very small vesi­cles. The breccia deposi ts display a beddedaspect in that they maintain consistent thick­nesses with definite upper and lower bound­aries. They are often associated withrhyolite or rhyolite glass flows and ordinarysiliceous tuff units. The spatial extent ofthe pumiceous rhyolite breccia is more limitedthan the associated tuffs and flows, whichprobably indicates closer proximity to aparent volcanic vent.

Pumiceous rhyolite is being utilized inboth portland cement concrete and concretemasonry units and in all size fractions, bothcoarse and fine. The fine fraction, unlikecinder, is sim'ilar in densi ty to the coarsebecause the tiny vesicles are evenly distrib­uted. In addition, both the coarse and finefractions are relatively stror¥J. Even thoughpumiceous rhyolite may be heavier than eitherpumice or cinder, the end product may besimilar in weight because the pumiceousrhyolite fines can be used.

DISTRIBUTION OF DEPOSITS

Figures 6 throu:Jh 8 show the general dis­tribution of known deposi ts of each of the NIAdescribed. As previously mentioned, youngvolcanics are found only in the western por­tion of the united States where there arelarge volcanic fields or individual volcaniccenters containing suitable glassy, low­densi ty rocks.

Although production estimates are givenbelow for each of the three aggregate types,they should be used with caution. Wide fluc­tuations in production occur in relation tothe economic health of the construction indus­try. In addition, for various reasons, pro­duction data from federal and state sourcesoften conflict. Available information doesnot always reflect the end product application- is the material beir¥J used as a lightweight

glossy rhyolite

Figure 5. Schematic cross section of a typical Quaternary rhyolite dome.

59

• one or more producers

•

• other deposits

• other deposits

• one or more producers

Figure 7. Distribution of volcanic cinderdeposits in the Southwest •

Figure 6. Distribution of pumice deposits inthe Southwest •

60

• •••• ••••••• •• • ••

• •••• ••

.. ~.• ••

•••

•• • •

•

••

•

• ..••

•

tt• •

•• •••...•••

•

• other deposita

•

•

•

•e.•

•

•

•

•

• present producer.

southern Cbso Range area, at the southern endof Owens Valley in Inyo Cbooty, is the largestcurrent producer in the state, furnishinglightweight aggregate to the southern califor­nia market. Chestennan describes these depos­its as being tuffs of both subaqueous and nueeardente origin. In northern california in theGlass Mountain area in eastern siskiyouCbooty, pumice from a recent, loosely consoli­dated tuff is produced and shipped as farsouth as the San Francisco Bay area. Minoramounts of pumice are produced periodicallyfrom other localities in california, includingthe Bishop and Mom lake region, and the frontranges of the Sierras near Fresno.. '!he major­ity of pumice production in california occur­red prior to the late 1950 1s. Counties withconsiderable past production include Siskiyou,Napa, Mono, Inyo, and Kern.

The principal pumice producers in NewMexico are mining material from tuffaceousdeposits located near santa Fe on the easternand southern flanks of a caldera that formsthe Jemez Mountains. Here the deposits arethe lower member of the Pleistocene BandelierTuff and may attain thicknesses as great as 70feet with little or no overburden. Past pro­duction has also taken place from tuffaceousunits near Gr"ants, west of Albuquerque. Minor

Figure 8. Distribution of pumiceous rhyolitedeposits in the Southwest •

61

•••

Fun ice

The distribution of pumice deposits in theSouthwest is shown in Figure 6. lI.ccordin] tostatistics from the U.S. Bureau of Mines,about 500,000 tons of pumice per year is pro­duced in the United States. '!he states of I:\IewMexico and california in the Southwest are twoof the four major pumice producing states inthe country. In 1982 New Mexico productionwas approximately 100,000 tons, while califor­nia1s production was approximately 60,000.Production in Arizona is less than 30,000tons, and I:\Ievada currently has no pumice pro­duction.

The most comprehensive description ofpumice in california is by Chestennan (1956).Those deposits having a history of utilizationinclude both subaerial and subaqueous depos­its, ranging in size from a few thousand tonsto many hundredS of thousands of tons. The

a;Jgregate? An example is volcanic cinder; theU.S. Bureau of Mines does not group this com­modity separately. In addition, the majorityof the cinder mined in the Southwest is notutilized as a lightweight aggregate, butrather as a substitute for sand and gravel orcrushed rock in other applications.

n

"

nj

r

tn

j

1na

nrnsse

rsn)

n

1nn

1

r

s

pumiceous rhyolite are often associated withthe pum ice deposits of Figure 6. Pumiceousrhyolites can be found in all the southwestern

I states, but the only production currently isin N3vada and Arizona.

Nevada, the largest producer, has threeactive pumiceous rhyolite deposits. NearReno, in northern Nevada, two producers areminin;] from rholi tic domes. The Reno area isby far the largest utilizer of pumiceousrhyolites, the value of these deposits havingbeen recognized over 25 years ago. Some ofthis material is shipped into nearby Sacra­mento, California. A third producer in N3vadais located just south of Las Vegas, where atuff breccia unit is being mined. In both LasVegas and Reno, the mater ial is used in bothconcrete masonry units and portland cementconcrete.

Arizona has one producing pumiceousrhyolite deposit, a tuff breccia unit approx­imately 60 miles east of Phoenix. Here thematerial is primarily used as a lightweightaggregate in concrete masonry units, but hasbeen occasionally utilized in portland cementconcrete as well.

New Mexico contains several young rhyo­litic domes containing pumiceous rhyolite thathave potential for use as a lightweight aggre­gate. Some effort has been made to put adeposit located near a major metropolitan areainto production, but conflicting land usageprecluded this possibility.

California contains abundant pumiceousrhyolite, both in domes and as tuff brecciaunits. No significant production has takenplace. There was an effort recently, however,to put a deposi t located near a major metro­politan area into production, but conflictingland usage again precluded this possibility.

Conclusion

Natural lightweight volcanic aggregatesare attaining greater application in theSouthwest primarily due to their recognizedeconom ic benef i ts to the construction indus­try, the rise in energy costs over the lastdecade, and the identification of new naturallightweight resources.

The geology and physical characteristicsof the NLA discussed here impart certainunique properties that make them suitable for

63

use in lightweight applications of portlandcement concrete and concrete masonry uni ts.Pumice is the lightest of the three naturallightweights, is very porous and, correspond­ingly, has the lowest physical strength. Vol­canic cinder is intermediate in weight, highlyporous, but generally, has good strength.Pumiceous rhyolite is heavier than pumice, andstronger, and, as a rule, heavier than cinderbut has a lower absorption. These basiccharacteristics of the three materials, aswell as others not discussed, govern the ulti­mate proportions and usage of the aggregatesin the end product, but all are employed inthe manufacture of lightweight constructionmaterials.

The outlook for increased usage of thesenatural lightweights should continue to im­prove as population and the construction in­dustries of the SJuthwest expand. The oppor­tunity exists for some previously exploitedresources to regain a market and for hertoforeunrecognized resources, especially the pumi­ceous rhyolites, to be developed. Pumiceousrhyolites may have the greatest potential forincreased utilization as a lightweight aggre­gate as they have been the least recognizedfor this purpose.

REFERENCES

Chesterman, C. W., 1956, Pumice, pumicite, andvolcanic cinders in Cal ifornia: Cal ifor­nia Division of Mines Bulletin 174, 119p., 4 plates.

Keith, S. B., 1969, Basalt and related rocks,in Mineral and water rerources of Arizona,Arizona Bureau of Mines Bulletin 180, p.315-320.

______~_' 1969, Pumice and pumicite, in Min­eral and water resources of Arizona:Arizona Bureau of Mines Bulletin 180, p.407-412.

Whi tson, D. N., 1982, Geology of the perlitedeposit at No Agua Peaks, New Mexico, inAustin, G. S., ed., Industrial rocks andminerals of the Southwest: New MexicoBureau of Mines and Mineral Resources,Circular 182, p. 89-95.

occurrences of pumice have been reportoo else­where in the state. Pumice is currently beingproduced from a deposi t near Flagstaff inNorthern Arizon~ where extensive pumiceoustuff units are a part of the San Franciscovolcanic field. Production is shipped primar­ily to the Phoenix area. Minor productionalso comes from a deposit approximately 25miles east of safford and is usoo locally.

Nevada currently has no pumice production.In the past, minor production came from twotuffaceous deposits near Fallon, in ChurchillCbunty, in the west central part of the state.Pumice deposi ts in Nevada are limited to thewestern portion of the state and tend to bevery limited in aerial extent and generally oflow quality. This is in contrast to the otherthree SOuthwestern states that have large,high quality pumice reserves.

Volcanic Cinders

Volcanic cinder is prooucoo in all four ofthe states in the southwest as shown in Figure7. Current production far exceeds that ofpumice because cinder is utilized in moreapplications and is more abundant. Volcaniccinder in many localities is used not only asa 'lightweight aggregate, but also as roadbaseand fill material where other traditionalsources of construction materials, such assand and gravel, are lacking. Cinder occursin great quantities in all four of the statesin the southwest. SOme of the larger volcanicfields contain hundreds of cinder cones whileisolated cones are also found as part ofsmaller, widely-distributed mafic eruptions.

Tbtal production in the western UnitedStates is probably on the order of many mil­lions of tons. This is difficult to pinpoint,however, because U.S. Bureau of Mines statis­tics often includes cinder production, becauseof its use, with crushed stone. Californiaand Arizona are the largest producers of vol­canic cinders for all applications. Tbtalproduction in Arizona of cinder is probably inexcess of 500,000 tons per year. Californiaranks next in production for lightweightapplications at slightly under the same ton­nage, followed by New Mexico, with approx­imately 150,000 tons, and lastly, Nevada, withless than 50,000 tons. The number of activeoperations varies from 15 in California toonly two in Nevada.

The principal source of supply of volcaniccinder in Arizona is from the San Franciscovolcanic field stretching from near Flagstaff,west to Ash Fbrk. At least seven deposits areactive in this area with most of the materialbeing produced for lightweight aggregateapplications and shipped south to the Phoenixarea for use in lightweight concrete masonryunits. The san Francisco volcanic field con­tains literally hundreds of extrusive centers,many of which are volcanic cinder cones.

62

Smaller amounts of cinder have been pro­duced from other mafic volcanic fields inArizona includirYJ the White Mountains near theeastern border, and the san Bernardino Valleyin the extreme southeast corner of the state.Nearly all production of volcanic cinder inArizona has been from Quaternary cinder cones.Further information concerning volcanic cinderin Arizona is described by Keith (1969); seeWelty and Spencer - this volume.

California volcanic cinder productioncomes from deposi ts in both the northern andsouthern parts of the state. Isolatoo cindercones at Little Lake in southern Inyo Cbunty,and at Pisgah Crater in the Mojave Desertfurnish lightweight aggregate for the SOuthernCalifornia market. In Northern California,cinder comes from the extensive volcanic fieldstretchirYJ from near Lassen Volcanic NationalPark north to the Oregon border, and fromisolated cinder cones in the Clear Lake areain lake Cbunty, north of san Francisco.

The extensive volcanic field from Lassennorth contains considerable reserves of cinderin at least a hundred cones. In southernCalifornia additional isolated cinder conescan be found from Mono Lake south into OwensValley and at Amboy in the central Mojaveresert. A small mafic volcanic field at Cima,close to the Nevada border, has several cindercones with some material beirYJ shipped to LasVegas for use as lightweight aggregate inconcrete masonry units. Chesterman (1956)describes in detail many of the cinder depos­its of California.

Volcanic cinder in New Mexico has beenmost recently discussed by OSburn (1982). Themajority of the production comes from severalcinder cones in an extensive volcanic field inthe northeast corner of the state in unionCbunty. Here the material is mined and ship­ped by rail to several nearby states for usein lightweight aggregate applications. Theseare the most easterly exploitable cinder de­posits in the country. Other lightweightaggregates are minoo near santa Fe, Albuquer­que, and northwest of EI Paso, Texas. Allproduction comes from Quaternary cinder cones.

The smallest producer of volcanic cinderin the SOuthwest is Nevada. Only two depos­its, both Quaternary, are currently in produc­tion; one being near Lathrop Wells in NyeCbunty in southern Nevada, which furnisheslightweight aggregate for a concrete blockplant in Las Vegas, and the other near CarsonCi ty in northern Nevada, which occasionallyfurnishes material for use in lightweightportland cement concrete. Nevada has fewercinder deposi ts than the other southwesternstates, and these are found as isolated cones,not large volcanic fields.

Pumiceous Rhyolite

The distribution of pumiceous rhyolite isshown in Figure 8. Rhyolitic domes containing

Acquisition of Federally Owned Industrial Minerals

A. G::mnon Varieties (row salable):1. Locatable until July 23, 1955 (see IV. B.)2. N=ver locatable (see IV. A.)

B. Uncommon Varieties - to qualify, a mineral must satisfy one ofthe followil'1g":1. Special use (because of intrinsic proJ?3rty givil'1g" distinct and

special value) .2. Higher price in the market (.because of intrinsic proJ?3rty

givirg distinct arx:1 special value) .3. lower prcx:iuction cost, so higher profit (because of intrinsic

property givif'g distinct anj special value) .

A. Eefore Materials Pet of July 31, 1947, most defOsits werelDlavailable tiOOer any system; after Materials Pet, they could bepurchased.

B. Materials locatable lDltil July 23, 1955; then salable, unlessvalid existif'g rights (see V. A. 1.. ).

V. CDMMJN VARIE:rIES Acr MINERAlS (30 USC 611)Sani, stone, gravel, punrce;-punicTEe,-orciooers

A. Before leasir-g act, rrost (except coal) were probably locatable.B. After leasil'1g" act, available only thrOl.gh lease, unless valid

existif'g rights.C. EXamples: oil, gas, coal, bituninous materials, berates,

.poosphate, p:Jtash, scx:liun, geothennal rerources

A. Widespread minerals of low unit value aoo used for ordinarypurrnses.

B. see V. A. 2.C. EXamples:'" crdinary clay; Peat; Material used for fill, levees,

am ballast

A. All "valuable mineral depJsi tsll rot excluied below.B. see V. B.c. EXanples:

II. MINERAlS~~

Alunite, Asbestos, Barium minerals, Bauxitic raw minerals,Chromite, Diamooos, Diatomite, EXceptional clay, Feldspars,Flwrspar, Glauconite, Gr"aphite, Q1psum and anhydrite, Kyaniteand related minerals, Lithium raw materials, Ma:;lOesite aoorelated minerals, Manganese, Mica, IIepheline Syenite, Olivine,Pyrophyllite, Rare Earths am 'Ihorium, Silica an:j Silioon,Staurolite, SUlfur, 'I~l1c, Titanium minerals, Vermiculite,Wollastonite, Zeolites, (dependifX,J on chemistry, sane areleasable)

Q.1ly one location up to 200 feet in length wasallowed along each lode or vein. Payment forpatent of lode claims was $2.50 per acre.

The Act of July 9, 1870 (16 Stat. 217)amended the Act of July 26, 1866 to includeplacer locations. It limited placer locationsto a maximum of 160 acres and required thatsuch locations conform to legal subdivisionson surveyed lands. Valid placer claims couldbe patented upon payment of $2.50 per acre.

The General Mining Law of May 10, 1872,replaced much of the 1866 and 1870 miningacts. Although the 1872 mining law has beenamended many times, it still remains sur­prisingly intact after more than 100 years.

64

ABS1W\Cr Table 1. Methods of acquisition of mostfederally owned industrial minerals.

REVIEW OF '!HE FEIERAL MINING lAWS

Teny S. MaleyU.S. Bureau of Land Management

Idaho state Office3380 Americana Terrace

Ebise, ID 83706

Federally owned mineral deposits generallyfall into one of three categories: (1)minerals locatable under the General MiningLaw of 1872; (2) minerals leasable under theMineral leasing Act of 1920; and (3) mineralssalable under the Materials Act of 1947.Unlike valuable deposits of gold, silver,copper, iron, lead, etc., which may be locat­able, industrial minerals are acquired througha variety of methods depending on use, com­position, and date of acquisition. Table 1may be used to establish the method of acqui­sition for most industrial minerals.

Ebr almost 200 years Cbngress has wrestledwith the problem of mineral disposal. Asearly as March 3, 1807 (2 stat. 448), a lawwas passed that authorized leasing of leadmines. Most mineral lands were disposed of bya leasing arrangement until the Acts of July11, 1846 (9 Stat. 37) and March 1, 1847 (9Stat. 146) authorized the sale of minerallands.

In 1848 gold deposits were discovered incalifornia. '!his stimulated tremendous con­troversies about how to dispose of Federalminerals. Most of the controversy was betweenthe Federal government and the State ofCalifornia. Both sides proposed severalschemes, inclu::Hng numerous proposals to taxthe mines, lease mineral lands, and sellmining permits. California miners preferredthat the state rather than the Federal govern­ment administer the disposal of minerals. Allthrough this period of controversy, rules andregulations proposed and established by theminers allowed a reasonable amount of stabil­ity in the mining camps. These ordinancesestablished a location system based on speci­fying claim size, location procedure, and workrequired to hold a claim.

The Act of July 26, 1866 (14 Stat. 251)was based on the rules and regulations incommon use by the miners. Not only did thislaw establish a single set of mining require­ments, but it also provided a means for theminers to obtain legal title to a mining claimupon expenditure of at least $1,000 per claim.The act declared all mineral lands owned bythe public open to exploration and location.

The 1872 law authorized placer- and lode-­mining claims, mill sites, and tunnel sites ofspecific dimensions. At least $100 worth ofwork was annually required on each claim tomaintain a possessory title. Placer claims,lode claims, and mill sites could be patentedupon expenditure of $500 worth of work, pro­vided the discovery requirements were met.

The Mineral Leasing Act of February 25,1920 (41 stat. 437) provided that deposits ofcoal, phosphate, oil, oil shale, gas, andsodium could be acquired only throU]h competi­tive and noncompetitive leasing systems. TheAct of April 17, 1926 (44 Stat. 301) madesulphur in public lands in New Mexico andLouisiana subject to the 1920 Leasing Act.The Act of February 7, 1927 (44 Stat. 1057)authorized that chlorides, sulphates, car­bonates, borates, silicates, or nitrates ofpotash be included as leasable minerals. '!heMaterials Act of July 31, 1947 (61 stat. 681)authorized disposal of sand, stone, gravel,and common clay throU]h a contract of sale.

Minerals Locatable Under the Mining Laws

Federal mining laws (30 usc sec. 22) statethe following:

Except as otherwise provided, allvaluable mineral deposits in landsbelonging to the United States, bothsurveyed and unsurveyed, shall befree and open to exploration andpurchase ••••If valuable mineral deposits are locat­

able, what then is a "valuable mineral depos­it"? The Federal regulations 43 CFR 3812.1define a locatable mineral in this way:

Whatever is recognized as a mineralby the standard authorities, whethermetallic or other substance, whenfound in public lands in quantityand quality sufficient to render thelands valuable on account thereof,is treated as coming within thepurview of the mining laws.Although this definition of a locatable

mineral is somewhat vague, it could undoubted­ly be applied to almost any mineral that hassufficient value to be extracted and marketedat a profit. Because of this value require­ment, there is no such thing as a list oflocatable minerals. For example, somedeposits of gold, uranium, and gemstones arevaluable, whereas other deposits are not.Whether or not a particular mineral deposit islocatable depends, therefore, on such value­influencing factors as quality, quantity,minability, demand, marketability, etc.

Minerals Nbt Locatable

Rather than attempting to establish whichminerals are locatable, it may be more prac-

tical to discuss which minerals are definitelynot locatable. The number of locatable min­eralsauthorizedby the. 1872 Mining Law hasbeen substantially reduced by severalsubse­quent Federal laws. The Mineral Leasing Actof 1920, as amended, autlnrized that the fol­l~wing deposi~s may be acquired only throU]h amIneral-leasIng system: oil, gas, coal,p~tassium, sodium, phosphate, oil shale, na­tIve asphalt, solid and semisolid bitumen andbituminous rock including oil-impregnated rockor s~nds from which oil is recoverable only byspecIal treatment after the deposit is minedor quarried, and sulphur deposits in LOuisianaand N3w Mexico. The Materials Act of July 31,1947 (61 Stat. 681), amended by the Act ofJuly 23, 1955 (69 Stat. 367), excluded commonvarieties of sand, stone, gravel, pumice,pumicite, cinders, and clay; however, uncommonvarieties of sand, stone, gravel, pumice,pumicite, cinders, and exceptional clay arelocatable. The Act of September 28, 1962 (76Stat. 652) removed petrified wood from thelocatable-mineral category.

Before the Materials Act of 1947 and theAct of JUly 23, 1955 were enacted, many min­eral materials were never locatable eventhoU]h they could be marketed at a profit. Infact, the Materials Act of 1947 was enacted toprovide a means to dispose of them. Materialin the category includes ordinary deposits ofclay, limestone, fill material, etc. Non­locatable minerals generally have a normalquality and a value for ordinary uses. InHolman et ale V. State of utah, 41 LD 314(1912), the question of whether clay was alocatable mineral was considered:

It is not the understanding of theDepartment that Congress has in­tended that lands shall be withdrawnor reserved from general disposi­tion, or that title thereto may beacquired under the mining laws,merely because of the occurrence ofclay or limestone in such land, eventhoU]h some use may be made commer­cially of such materials. There arevast deposits of each of thesematerials underlying great portionsof the arable land of this coun­try ••••

other Federal court and departmental decisionshave found that such minerals as decomposedrhyolite, windblown sand, peat moss, and sandand gravel, if suitable only as fill, soilconditioners, or other low-value purposes,were never locatable.

Lands Open to Exploration

The mining law states that "except asotherwise provided, all valuable mineral de­posits in lands belonging to the UnitedStates, both surveyed and unsurveyed, shall befree and open to exploration and purchase, by

claims are located on unsurveyed lands. Ifthe claims conform to such legal subdivisions,no further surveyor plat is required forpatent. On unsurveyed land and in certainsi tuations, placer claims may be located bymetes and bounds.

J:ib location for a placer claim may exceed20 acres for each individual who participates.An association of two locators, however, maylocate 40 acres; three may locate 60 acres;and so on. The maximum area that may beembraced by a single placer claim is 160 acresand such a claim must be located by an associ­ation of at least eight persons. aorporationsare limited to 20-acre claims. A 20-acreplacer claim might be described as being in N1/2 NE 1/4 NW 1/4 sec. 5, T. 5 N., R. 3 W.,Eoise Meridian.

uncommon varieties of building stone maybe located with placer-type claims pursuant tothe Act of August 4, 1892 (27 stat. 348; 30USC Sec. 161). The law requires thatbuilding-stone placers may be located only onlands "that are chiefly valuable for buildingstone." The Act of July 23, 1955 (69 Stat.367; 30 USC Sec. 611) withdrew common varie­ties of building stone from entry under themining laws.

Lode Versus Placer

Many mineral deposits do not fit easilyinto the category of either a lode or placerdeposit. As stated previously, the onlystatutory guidance concerning the definitionof a lode claim is in section 2 of the 1872mining law:

" •••mining claims upon veins orlodes of quartz or other rock inplace bearing gold, silver, cinna­bar, lead, tin, copper, or othervaluable deposits ••••"

The statutory definition of a placer claim (30USC Sec. 35) includes "all forms of deposit,excepting veins of quartz or other rock inplace." The key definition is that given fora lode-mining claim. Many court decisions, inconsidering the definition of a lode, general­ly have held that the shape or nature of thedeposit is more significant than its origin.This is just as well because the origin of aparticular deposit may be difficult to ascer­tain, especially where associated with meta­morphic rocks.

There are several advantages that a placerlocation offers over a lode location: (1)only one discovery of mineral is required tosupport a placer location whether it be 20acres or 160 acres; however, each 10-acresubdivision must be mineral in character; (2)$100 worth of work must be expended on aplacer claim whether it be 20 acres or 160acres; and (3) if the claim is to be locatedon surveyed lands, it can be described bylegal subdivision. A placer location, there-

67

fore, is more easily and cheaply effected thana lode location and more secure from rivalclaimants.

Mill Sites

The Federal requirements for mill sitesare set forth in 30 USC Sec. 42 and 43 CFR3844. Mill-site locations shall not exceed 5acres in size. The land under location mustbe nonrnineral and noncontiguous to the vein orlode. Although a mill site may adjoin theside lines of a lode-mining claim, it is un­likely that lands adjoining the end lineswould be either nonrnineral or noncontiguous tothe vein.

The Federal law authorizes three generalcategories of mill sites:

1. A mill may be located if needed by theowner of a lode-mining claim for mining andmilling purposes. Such a mill site may bepatented with the associated lode claim and issubject to the same survey, notice require­ments, and charges that apply to lode claims.2. The Act of March 18, 1960 authorized thelocation of a mill site if needed by the ownerof a placer claim for mining, milling, proc­essing, beneficiation, or other operations inconnection with such a claim. Such a millsite may be patented with the aSq<iciatedplacer claim and is subject to the'samesui­vey, notice requirements, and charges thatapply to placer claims.3. A mill site may be located to establishand maintain a custom or independent quartzmill or reduction works. The owner of such amill need not own a mine in connection withthe milL A custom mill may qualify forpatent in the same manner as mill siteslocated in connection with lode claims.

There is no information in the Federal lawor regulations concerning how a mill site or,how many, may be located. It may be presumedthat a mill site may be located by legalsubdivision, if associated with a placer claimthat is located by legal subdivision; andconversely, a mill site may be located bymetes and bounds, if associated with a lodeclaim.

Tunnel Sites

Tunnel locations are made by erecting asubstantial post or monument at the tunnelentrance. Stakes or monuments should beplaced along the line of the tunnel at appro­priate intervals up to 3,000 feet from theentrance. The owner of a mining tunnel hasthe possessory right to 1,500 feet of anyblind lodes cut, discovered, or intersected bythe tunnel. This gives the locator of thetunnel the exclusive right to prospect an area3,000 feet by 3,000 feet while work on thetunnel continues. Claims staked by other

citizens of the united states and those whohave declared their intention to become such."(Act of May 10, 1872; 17 Stat. 91; 30 USC 22.)

Publ ic lands belong ing to the Uni tedStates are open to entry under the GeneralMining Laws .unless particular lands have beenwithdrawn by congressional authority or by anexecutive authority either expressed orimplied. [Lockhart v. Johnson, 181 us 516(1901).] -

Mining claims may be located on unre­served, unappropriated lands administered bythe Bureau of Land Management (BLM), U.S.Department of the Interior and or unreserved,unappropriated public-domain lands in nationalforests administered by the Forest Service,U.S. Department of AJriculture. Mining loca­tions may be made in the States of Alaska,Arizona, Arkansas, California, Colorado,Florida, Idaho, Louisiana, Mississippi,Montana, Nebraska, Nevada, New Mexico, IDrthDakota, Oregon, South Dakota, Utah, Washing­ton, and Wyoming. [43 CFR 3811.2-1(a).]

Lands patented under the Stockraisingfbmestead Law or ot~er land-disposal laws thatreserved locatable minerals to the UnitedStates are subject to mineral location. Themineral reservation in the patent separatesthe land into a surface estate and a subsur­face mineral estate. The mineral estate issubject to location under the general mininglaws in the same manner as are vacant, unap­propriated public lands. The surface owner,however, is entitled to compensation for anydamages reSUlting from exploration or mining.

Lands Closed to IDeation

The national parks and national monumentsare closed to mining location; however, validmining claims that were in effect when anational park or monument was established areentitled to certain grandfather rights.Indian reservations, military reservations,most reclamation projects, Federal wildliferefuges, and land segregated under the Classi­fication and MUltiple Use Act are generallyclosed to mining location.

Numerous land withdrawals and land classi­fications have served to segregate the publiclands from mineral location and entry. Beforea mining claim is located, the pUblic landrecords of the Bureau of Land Managementshould be examined to determine if the area ofinterest is available for mineral entry. Amineral location on lands segregated frommineral entry would not only be a waste oftime and money, but would also be an unautho­rized trespass.

Reserved Minerals IDt Subj ect toMining Law Without specific Authority

It is well established that where locat­able minerals are reserved in a Federal land

66

patent or disposal, the reserved minerals arenot open to location of mining claims. Forexample, reserved minerals in patents issuedunder the Recreation and Public Purposes Act(43 USC 869) are not open to mineral location.The only exception to this rule is where thestatute authorizing the disposal specificallyprovides that the reserved minerals are sub­ject to the mining laws, as does the StockRaising Homestead Act of 1916. [City ofPhoenix v. Reeves, 14 IBLA 315, 327-28(1974).]

Types of Claims and Sites

The mining law authorizes four types ofappropriations: lode claims, placer claims,mill sites, and tunnel sites. Each type hasits own method of location and purpose.

Lode- Mining Claims

Lode-mining claims may be located upondiscovery of a vein or lode "of quartz orother rock in place bearing gold, silver,cinnabar, lead, tin, copper, or other valuabledeposits" (30 USC Sec. 23). A lode claim maynot exceed 1,500 feet in length along thecourse of the vein or lode, nor extend morethan 300 feet at the surface along either ofside of the middle of the vein. The dimensionsof a lode-mining claim, therefore, must notexceed a parallelogram 1,500 feet in length by600 feet in width. Federal law also requiresthat the end lines of each claim be parallelto each other.

Federal regulations (43 Cr'R 3841-5) speci­fy that certain information must be containedin the location notice. The course and dis­tance from the discovery shaft on the claim tosome permanent, well-known object, such asstone monuments, blazed trees, confluence ofstreams, intersection of roads and prominentmountains, must be described as accurately aspracticable. Survey monuments such as brass­cap section corners are excellent markers,especially because the Federal law (30 USCSec. 23) requires that the location of theclaims must be designated with reference tothe lines of the public survey if such claimsare on surveyed lands. It is not necessary,however, that the claims conform to thepublic survey. R>st or stone monuments shouldbe established at the corners of the claim tomark the claim boundaries.

Placer- Mining Claims

Placer claims may be located for "allforms of deposit, excepting veins of quartz orother rock in place" (30 USC Sec. 35). Allplacer-mining claims must conform as closelyas practicable with the U. S. system ofpublic-land surveys and the rectangular sub­divisions of such surveys, even though the

Statutory Definition of DiscoveryThe Act of May 10, 1872 (30 USC 22) states

that " ••• all valuable mineral deposits inlands belonging to the Oni ted States ••• shallbe free and open to exploration and pur­chase ...."

Al though the statutes do not prescribe atest for determining what constitutes a dis­covery of a valuable mineral deposit, thedepartment (BLM) and the courts have estab­lished a test through almost a century ofdecisions. These decisions seem to assumethat Cbngress intended that "valuable mineraldeposits" be valuable in an economic sense orcould be worked as a paying mine. A profit­able mining operation has always been con­sidered as the best evidence of the discoveryof a valuable mineral deposit.

No Discovery If Deposit WarrantsAdditional ExPIoration

It is a common pitfall for a claimant orhis expert witness to reveal at the hearingthat the deposit is mineralized to the extentthat it justifies additional exploration orprospecting to find a commercial deposit. Thehearing officer considers this to be an admis­sion by the claimant that there is no dis­covery,but simply evidence that one mayexist. This does not meet the present courtinterpretation of discovery that requires thata valuable mineral deposit has been found andis ready for development and mining. With adiscovery, no more prospecting or explorationwork to find the deposit would be necessary.

Numerous recent departmental and courtdecisions have held that in order to qualifyas a discovery it must be established that themineral deposit can be mined and sold at aprofit and the development and mining opera­tions may proceed with rearonable confidence.If the deposit requires additional explorationto delineate the ore reserves and determinegrade or quality before development may beconfidently started, a discovery has not beenmade.

paying-Mine Need To Be Demonstrated

Although a mining claimant may be requiredto demonstrate that he has what could be de­veloped into a profitable mine under presenteconomic conditions, it is not required thathe demonstrate a paying mine as an accomplish­ed fact. In Adams v. U.s., 318 F2d 861 (9thCir. 1963) the Cburtstated:

"Discovery of a valuable mineraldeposit within the limits of eachclaim is essential but value, in thesense of proved ability to mine thedeposit at a profit, need not besrown. "

Undoubtedly though, the most convincing demon­stration of a valid discovery would be a mine

69

presently operating at a prof i t. In Barrows~ Hickel, 447 I!'2d 80, 82 (9th Cir. 1971) theCourt said that "actual successful exploita­tion of a mining claim is not required tosatisfy the 'prudent-man test'~'

~ of Discovery

Worked-out claims do not qualify as validmining claims. Although a mining claim mayhave been valid in the past because of dis­covery of a valuable de[Osit of mineral on theclaim, the claim will lose its validity if themineral deposit ceases to be valuable becauseof the change in economic conditions, or themineral deposit is depleted.

Discovery in Each Claim

In contest proceedings involving more than ­one claim, the test of discovery is applied toeach claim individually, because "( a) discov­ery without the limits of the claim, no matterwhat its proximity, does not suffice~

[Waskey ~Hammer, 223 US 85,91 (1912)]. Inorder to be valid each claim in a claim groupmust have a discovery within its boundaries.Under certain circumstances, however, thegovernment has taken a broad look at thisrequirement. For example, in the case oflarge, low-grade, prophyry-copper depositsthat by necessity require hundreds of claimsto cover the mineralized area, it is obviousthat anyone claim could not stand by itselfas a paying mine. The entire deposit must beavailable in order to be economically feasi­ble. In acknowledging this fact, the govern­ment has issued mining patents on numeroussuch claims.

validity at Date of Withdrawaland Date of HearJ:n;j

When land is closed to location under themining laws subsequent to the location of amining claim, the claim cannot be recognizedas valid unless all requirements of the mininglaws, including discovery of a valuable min­eral deposit, were met at the time of thewithdrawal and at the time of the hearing.[U.s.~Netherlin, 33 IBLA 86 (1977).] Whereland occupied by a mining claim has been with­drawn from operation of the mining laws, thevalidity of the claim must be tested by thevalue of the mineral deposit as of both thedate of the withdrawal, and the hearing.[U.s. ~ Chappell, 42 IBLA 74 (1979).] Eventhough there may have been a discovery at thetime of the withdrawal or sane other time inthe past, a mining claim cannot be consideredvalid unless the claim is at present supportedby a discovery. A loss of discovery, eitherthrough exhaustion of minerals, changes ineconomic conditions, or other circumstances,results in loss of the location. [U.s. v.Wichner, 35 IBLA 240 (1978).] -- -

parties after the tunnel is started for lodesthat are not apparent at the surface but arewithin the area claimed by the tunnel locatorare invalid. The miner is entitled to locatelode claims to cover the veins intersected bythe tunnel; however, if work on the tunnelceases for 6 months, the tunnel locatorabandons all rights to undiscovered veins onthe line of the tunnel.

A notice of location must be posted onthe monument at the tunnel entrance and filedin the county recorder's office of the countyin which the tunnel is located. The notice oflocation should include the following informa­tion: (1) names of the locators; (2) actualor proposed direction of the tunnel, includingtunnel height and width, and (3) distance fromthe entrance to some established surveymonument or well-known permanent object.

Location Procedure

Before locating a claim, one should verifythat the lands of interest are open to minerallocation by examining the land-status maps andrecords at the Bureau of Land Management.Unpatented claims are recorded in the countyrecorder's office of the county in which theclaim is located. There are four basic stepsto location procedure: (1) discovery of avaluable mineral deposit; (2) marking theboundaries of a claim on the ground; (3)posting and recording the location notice withthe county recorder and the BLM; and (4) dis­covery work if required by state law.

The appropriate state law should be con­sulted to determine monument speci fications,manner of monumenting, information required inthe location notice, and recording require­ments.

Marking Claim Boundaries

Federal law requires that "the locationmust be distinctly marked on the ground sothat its boundaries can be readily traced" (30usc Sec. 28). Each State generally has de­tailed statutory requirements for markingclaim boundaries. Most states require that amonument of specific dimensions and materialsbe placed at each corner of the claim. Placerclaims located by legal subdivision generallydo not require corner monuments. Materialsused for monuments include posts, blazedtrees, and piled rocks; however, the mostcommon monument by far is the 4-inch-squarepost.

It is very important to mark the claimboundaries clearly with durable monumentsbecause the position of the monument on theground will generally prevail over the record­ed description. The more difficult it is tomove or destroy a monument, the less likelythe claim will be overstaked. It is prefer­able to overlap claims slightly rather than toomit desired land unintentionally.

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The Location Notice

Most States have laws that provide de­tailed procedures for posting and recording.Individual state requirements should bechecked frequently because state law isamended from time to time. Regardless ofwhether or not a particular state requires alocation notice to be posted and recorded, itis prudent to do so to make one's interest inthe claim a matter of public record.

Because monuments placed in the field areeasily lost or destroyed, a copy of the loca­tion notice should be recorded in the countyrecorder's office of the county in which theclaim is located as soon as possible, eventhough individual states may allow up toseveral months. In Alaska the recordingoffice is under the District Magistrate.

Although the information that must beincluded on a location notice varies fromState to State, the following are usuallyrequired: (1) date of location; (2) name ofclaim; (3) name of locator(s); (4) type ofclaim (placer or lode); (5) mineral or min­erals claimed; (6) distance claimed alongstrike of vein from discovery monument to eachend line; (7) direction of vein; (8) lengthand width of claim; (9) portion of section,township, and range and total acreage (forplacer claims located by legal subdivision),and (10) give the distance and direction fromdiscovery or corner monument to a fixed placesuch as a brass-cap section corner or to awell-known natural object or landmark such asa mountain, road intersection, or stream con­fluence.

It is extremely important that the record­ed location notice has an accurate descriptionof the claim location. Many claims have sucha vague description that they could existanywhere over a large area. A big problem inconnection with such a claim is that it couldbe moved to overlap a subsequent discovery inthe vicinity. Because such claims, oftenreferred to as "floating claims", record anearlier location date, they could present aserious threat to the locator of a new dis­covery.

Many States provide a procedure to file anamended location notice and still retain theoriginal location date if the earlier locationnotice contains a minor defect. Such correc­tions generally involve adjustments of theclaim boundaries or reorientation of the claimto align it more with the trend of the vein.

section 314 of the Federal Land :EQlicy andManagement Act requires recordation of thelocation notice with the State office of theBureau of Land Management wi thin 90 days ofthe date of location. A copy of the samenotice must also be recorded with the appro­priate county recorder's office within 60 to90 days of the date of location. One shouldconsult state law for the prescribed period.

Exposure of New Reserves or Increasein MineraJLPrice after Withdrawal

If a discOl1ery did not exist on a claim atthe date of withdrawal, a later discoveryestablished by subsequent mineral exposures orrise in mineral commodity prices would notgive a claim validity at the date of a hear­ing •

The Marketability Test

The marketability test has been followedby the Department of the Interior since Laymanv. Ellis, 52 LD 714 (1929). The applicationof the test was expressly upheld in Foster~Seaton, 271 F2d 836 (DC Cir. 1959). It wasfurther approved by the Supreme Court as acomplement to the prudent person test in u.s.v. Coleman, 390 US 602 (1968), which pointedout that" prof i tabil i ty is an important con­sideration when applying the prudent-mantest." See also, Converse v. Udall, 399 F2d6Hj, 621 (9th Cir. 1968), cert."""dei1led, 393 US1025 (1969), which indicate that the market­ability test is applicable to all miningClaims, including those containing preciousmetals.

The Foster v. Seaton Case

In Foster v. Seaton, supra at 838, theCburt upheld the-requirement for present mar­ketability followed by the Interior Departmentsince Layman v. Ellis, 52 ill 714 (1929):

with respect to widespread nonmetal­lic minerals such as sand and gra­vel, however, the Department hasstressed the additional requirementof present marketability in order toprevent the misappropriation oflands containing these minerals bypersons seeking to acquire suchlands for purposes other than min­ing. Thus, such a "mineral locatoror applicant, to justify his posses­sion, must show that by reason ofaccessibili ty, rona fides in devel­opment, proximity to market, exis­tence of present demand, and otherfactors, the deposit is of suchvalue that it can be mined, removedand disposed of at a profit."[Layman ~ Ellis, 54 ID 294, 296(1933) .]

The Coleman Case

In U.S. v. Coleman, supra, Mr. JusticeBlack, speaking for a unanimous Supreme Cburt,approved the requirement of the secretary that"the mineral can be 'extracted, removed andmarketed at a profit' - the so-called 'mar­ketability test'" (390 US at 600, 602-603).

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Essentially, in Coleman the Court deter­mined that nonmetallic minerals of widespreadoccurrence must be marketable at a profit.Al though the Court said the prudent man testand the marketability test are complementary,this is difficult to reconcile because theprudent man test implies prospective profita­bility, whereas the marketability test impliespresent profitability.

Marketability at ~ Profit

Many recent Department of Interior andFederal court decisions have required market­ability at a profit. In U.S. v. Coleman, 390US 599 (1968), the supreurr.e-Court held that"profitability is an important considerationin applying the prudent man test. •.•" InRoberts v. Morton, 549 F2d 158 (lOth Cir.1977), theCourt also indicated that market­ability at a profit is relevant to a claim forprecious metals.

Proof of profitable Market

In u.s. v. Gould, A-30990 (May 7,196~the Department of Interiorheld that it ••••does not require amining claimant to prove a discoveryby showing that he is actually en­gaged in profitable mining opera­tions or even that profitable opera­tions are assured, but it does re­quire a showing of a prospect ofprofit which is sufficient to invitereasonable men to expend their meansin attempting to reap that profit byextracting and marketing the min­eral, as distinguished from evidenceof value which will entice men toinvest their money only in gainingcontrol over land and holding it inthe hope or expectation that at afuture date the land may be found tobe valuable for the minerals whichit contains.In Barrows v. Hickel, 447 F2d 80, 82 (9th

Cir. 1971), the Court held that "actual suc­cessful exploitation of a mining claim is notrequired to satisfy the prudent man test."

Amount of Profit

One of the most common questions byclaimants concerning the profitability re­quirement is how much profit is necessary tovalidate a claim. In several interestingcases the Interior Department addressed theprofitability requirement in terms of theamount of profit necessary to establish adiscovery. In U~. v. Barrows, A-31023(November 28, 1969), the Board held that aprofit as low as $245 per year would notsatisfy the prudent man test of discovery.

In U.s. v. Penrose, 10 IBLA 334 (1973) theB::>ard indicated that although a sale of $1.00could represent a profit to a claimant, itwould not meet the prudent-person test.

Marketability Applies to All Minerals

The question of whether the marketabilitytest is applicable to intrinsically valuableminerals such as base and precious metals hasbeen considered in a number of cases. InConverse v. Udall, 399 F2d 616 (1968), perhapsthe most frequently-ci ted case on this sub­ject, the court held that the marketabilitytest, inclooing the profit factor, was appli­cable to all mining claims including thosecontaining precious metals.

Presently Marketable at aProfit: New Definition

The Interior Board of Land Appeals hassignificantly refined the prooent-person testby defining "presently marketable at a profit"to mean that the claimant "must stow that as apresent fact, considering historic price andcost factors and assuming that they will con­tinue, there is a reasonable likelihood ofsuccess that a paying mine can be developed."[In re Pacific Coast Molybdenum, 78 IBLA 16,29;" 90 I.D. 352 (1983).] This new definitionwas made in response to large fluctuations inmineral commodity prices that occurred duringthe preceding five years. Now a claimant isnot stuck with the latest market price of acommodity, but instead may average prices overan appropriate period of time. The Board,however, did caution that "situations canoccur in which structural economic changes ortechnolog ical breakthroughs inval idate his­torical conditions as a guide to present mar­ketabil i ty." For example, mineral priceselevated artificially by Government pricesupports would not be relevant to the questionof present marketability. Also the possibil­ity that a future stockpiling program mightsomeday be initiated would be "essentiallyspeculative and could not serve as a predicateupon which a prudent man would have proceededto expend time and money with a reasonablehope of success." [Id at 30.]

Market Too Small for Profitable operation

In U.S. v. Husman, 81 IBLA 271, 278(1984), the B::>ard determined that there was amarket for chemical-grade (locatable) lime­stone; however, this market could not supportan operation of the size necessary to estab­lish a profitable operation.

Tenth Circuit Approves Presumptionof Invalidity Where Lack of Development

In U.s. v. Zweifel, 508 F2d 1150 (10thCir. 1975), the Tenth Circuit Court approved

the Interior Department's requirement con­cerning the presumption of invalidity whereclaims were held several years with no devel­opment. The <burt said:

If mining claimants have held claimsfor several years and have attemptedIi ttle or no development or opera­tions, a presumption is raised thatthe claimants have failed to dis­cover valuable mineral deposi ts orthat the market value of discoveredminerals was not sufficient to just­ify the costs of extraction. [508F2d at 1156, n.5.]

Lack of Marketing (Sales) isNot Proof of Invalidity

In Rodgers v. U.S., 726 F2d 1376, 1379(9th Cir. 1984) ,It was held that "althoughlack of actual marketing of the mineral by theclaiman t may be relevant to the question ofmarketability, it is not conclusive proof ofinvalidity of claim. And on the same point,the Court in Barrows v. Hickel, 447 F2d 80, 82(9th Cir. 1971) said that "actual successfuleXploitation of a mining claim is not requiredto satisfy the "prudent man test." In Rodgers~ U.s., supra, the Court apparently accepteda lack of sales because the claimants "neededto accumulate an inventory before breakinginto foreign market."

Proof of Ev idence of Sales Records

In a number of Interior Department andFederal court cases, it has been held that itis the responsibility of the claimant to main­tain adequate business records relating toboth sales of the mineral product and costs ofproduction.

U.S. v. Arbo, 70 IBLA 244 (1983) is anexcellent-example of where a claimant had norecord of sales. Although the appellant sup­plied a number of receipts in:l icating sales ofgold to several different companies, he wasnot able to show the costs of producing thegold or even to document that the gold camefrom the contested claim. It is not uncommonfor the owner of a placer-gold claim to have apoor record of receipts in sane cases becausethe gold is recovered in a highly marketablecondition and there may be a temptation tomarket the gold in such a manner as to avoidincome taxes. However, as the Board pointsout below, you cannot have it both ways, ie.,get credit for sales in a contest action forwhich there is no income tax record of sales.

Marketability Must Not Depend on ValueAdded by Manufacture

It is well established that marketabilityof a mineral must be based on the mineral inits raw state rather than depend on value

71

added by manufacture. In U.S. v. Mansfield,35 IBLA 95 (1978), it was held that "anydetermination of the value of the contestee'sclaims, must rest on the marketability of theobsidian in its rough form and not upon anyenhanced value from subsequent processing orcraft work."

Marketing of Cbmparable Materialfrom other Claims

In Melluzzo v. Morton, 534 F2d 860, 863(9th Cir. 1976~ the court held that a"claimant need not rely on his own successfulmarketing efforts to prov 1" marketability ofhis material. If the successful marketing byothers has sufficiently established that theclaimant's comparable material is itself mar­ketable, that can suff ice." It should bepointed out that in this case the Court wasmaking reference as to how sales of materialby one claimant may establish marketabilityfor another claimant who has comparablematerial but no record of marketability.

In Rodgers v. U.s., supra, the Cburt heldthat the successful marketing by a claimant ofa gem material from one claim in a claim groupcould satisfy marketability for the otherclaims that had comparable material. TheCourt also indicated that this concept ofcomparable material would apply even thoughthe market was already preempted by the pro­ducing claims and that there is an abundanceof comparable material from other sources inthe area.

In Dredge Corp. v. Conn, 733 F2d 704, 707(9th Cir. 198~ft was held that "theclaimant cannot rely solely on the fact that.comparable material is being marketed.Rather, 'the claimant must establish that hismaterial was of a quality that would have metthe existing demand, and that it was market­able at a profit.' Melluzzo v. Morton, supraat 863." Dredge Corp. v. Conn, supra at 707."Proof that neighboring claims are being mar­keted is relevant to determining a claim'smarketab il i ty, but such proof alone does notovercome evidence that the market was wellsupplied. ••• Thus, even though comparableclaims are being mined, a new claim may beunprofi table because the market has reachedsuch a point of saturation that a new entrantcannot make a profit." [Id at 707.]

Prospective Market or ReservesWith No Market

In many parts of the west, minerals sub­ject to the mining law are covered by largeclaim groups. Where such minerals are wide­spread with vast reserves, it is not uncommonfor the claims or claim groups to cover sub­stantially more reserves than the market couldever absorb. These materials tend to be non­metallic minerals without intrinsic value such

72

as building stone, sand and gravel, bentonite,silica sand, pumice, perlite and many otherconstruction materials. In Barrows v. Hickel,447 F2d 80 (9th Cir. 1971), the court said at83:

The marketability test requiresclaimed materials to possess valueas of the time of their discovery.IDeations based on speculation thatthere may at some future date be amarket for the discovered materialcannot be sustained. What is re­quired is that there be at the timeof discovery, a market for the dis­covered material that is sufficient­ly profitable to attract the effortsof a person of ordinary prudence.In Baker v. U.s., 613 F2d 224 (9th Cir.

1980), the Court held that the Board's appli­cation of the excess reserves rule exceededits discretionary and statutory powers, andwas arbitrary, capricious, and an abuse ofdiscretion. Thus, the Court held that therecan be no such thing as an "excess reservestest" or a "too much test."

In Oneida Perlite, 57 IBLA 167 (1981), theBoard gave a thorough review of the case lawon the subject of reserves for which there isno market. The Board defined "reasonable"reserves as follows:

What amount of reserves is "reason-­able" is a determination to be de­cided on the basis of the evidencein each case. The nature of themineral, its unit value, the extentof the market, and whether it isexpanding or diminishing, the amountof similar mineral which can supplythat market from other sources,might all bear on the question ofwhether the location of additionalclaims for the same mineral wasjustified as the act of a prudentman in the reasonable bel ief that bythe expenditure of his labor andmeans a valuable mine might be de­veloped on each such claim.The Board concluded its lengthy decision

by giving the present status of the term"excess reserve" and stating that the realissue is marketability or economics. TheBoard said:

As hereinbefore indicated, a refer­ence to "excess reserves" does notdescribe a new rule of law inventedby this Department, or a super­imposition of a new test of aclaim's validity on the existinglaw. It is nothing more or lessthan a descriptive phrase applicableto a particular set of circumstan­ces. It describes the location ofclaims for far more land and mineralthan reason and prtrlence v.Duld allowbecause there is such a superabun-

dance of the material that the mar­ket simply cannot accept all of itat a profit. '!herefore , some of thedeposi ts must be regarded as notvaluable in an economic sense. '!hisconcern for excess reserves isrooted in the basic statute, 30 USCSec. 22 (1976), and controlled bythe "prudent man" test of discoveryas complemented by the requirementthat the economic value of thedeposit be measured by a determina­tion of whether it is presentlymarketable at a profit. In themaking of this determination, it isappropriate to consider the magni­tude and sources of other suppliesof that mineral to the same market.

Hypothetical Market at a Critical Date

The Act of July 23, 1955, as well as manywithdrawal actions have caused certain min­erals to no longer be open to location underthe mining law. However, valid claims forsuch minerals existing at the date of thewithdrawal remain valid so long as a discoveryexisted then and continues to the present.When the united States investigates thevalidity of such claims, it is necessary toapply the marketability test at both the crit­ical date and the present. In cases whereminerals from a claim were not being mined andmarketed at the critical date, it must bedetermined whether or not the minerals, ifproduced, could've been (theoretically) mar­keted •

Cbntinuous C{)eration is not Requiredcuring Critical Period

In Charlestone Stone products Cb., Inc. v.Andrus, 553 F2d 1209 (9th Cir. 197~reversedin part on other grounds, 436 US 604 (1978),the Court held that failure of a claimant tomaintain continuous operations during a crit­ical period is not required for provingvalidity of a claim. A "critical period"refers to that period of time between the dateof withdrawal and the present time duringwhich a showing of marketability must be main­tained.

In Rawls v. U.S., 566 F2d 1373 (1978), theCourt held that"absence of sales in thecritical period, though relevant, will notalone support a finding of unmarketability andnondiscovery. When there is little or noevidence of pre-1955 sales, a court shouldconsider costs of extraction, preparation andtransport as well as the level of then­existent market demand:'

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Cbmmon and Uncommon Varieties

Statutory Authority for DisposingCommon variety Minerals

Section 601 of Title 30 of the UnitedStates Code authorizes the Secretary of theInterior to sell "common varieties" of "sand,stone, gravel, pumice, pumici te, cinders andclay." On July 23, 1955, Public Law 167 (69Stat. 368; 30 USC 611) was passed to, amongother things, prohibit further location ofcommon variety minerals. The Act stated inpart:

No deposit of common varieties ofsand, stone, gravel, pumice, pumi­cite, or cinders and no deposit ofpetrified wood shall be deemed avaluable mineral deposit within themeaning of the mining laws of theUnited States so as to give effec­tive validity to any mining claimhereafter located under such mininglaws.

However, the Act went on to provide for anexception to "uncommon variety" minerals at 30USC 611:

Cbmmon varieties as used in sections601, 603, and 611 to 615 of thistitle does not include deposits ofsuch materials which are valuablebecause the deposit has some prop­erty giving it distinct and specialvalue and does not include so-called"block pumice" which occurs innature in pieces having one dimen­sion of two inches or more.

Therefore, the statute clearly implies that"uncommon varieties" of such materials existand are still locatable under the mining law.Uncommon varieties are "valuable because thedeposit has some property giving it dis­tinct and special value ••••"

As a basis for determining under whatcircumstances a deposit of "sand, stone, gra­vel, pumice or cinders" may be located, theremainder of this chapter is primarily devotedto what the Federal Cburts and Interior De­partment have interpreted too phrase "propertygiving it distinct and special value" to mean.

The Interior Department has attempted,with little success, to define "common varie­ties" by regulation (43 CFR 3711.l(b»:

"Cbmmon varieties" includes depositswhich, althm.gh they may have valuefor use in trade, manufacture, thesciences, or in the mechanical orornamental arts, do not posses adistinct, special econanic value forsuch use over and above the normaluses of the general run of suchdeposits. Mineral materials which

occur commonly shall not be deemedto be "common varieties" if a par­ticular deposit has distinct andspecial properties making it commer­cially valuable for use in a manu­facturing, industrial, or processingoperation. In the determination ofcommerc ial value, such factors maybe considered as quality and quant­ity of the deposit, geographicallocation, proximity to market orj;Dint of utilization, accessibilityto transportation, requirements forreasonable reserves consistent withusual industry practices to serveexisting or proposed manufacturing,industrial, or processing facili­ties, and feasible methods for min­ing and removal of the material.Limestone suitable for use in theproduction of cement, metallurgicalor chern ical grade limestone, gypsum,and the like are not "common vari­eties." This subsection does notrelieve a claimant from any require­ments of the mining laws.

Stone Versus Mineral or Element

Because common varieties of sand, stone,gravel, pumice, pumicite or cinders generallyconsist of an aggregate of two or more ele­ments and (or) minerals, the properties ofeach are not particularly significant. It isimportant to note that in this context we aretalking about minerals in the "scientific"sense rather than the "legalll or lIeconomicllsense. In fact, it is quite uncommon forminerals to be used in the scientific sense inany Interior or court decision. Ibwever, inU.S. v. pier ce, 7 5 I D 27 0 (l 9 68 ); U.S. v.'i3i:inkowski, 79 ID 47 (1972); and U.s. v. Bear;23 IBLA 378 (1976), the Board did use theterm IImineral" as a geOlogist would.

As an example of how the Board made adistinctionn between "stonell and IImineralll inpierce, Bunkowski, and Beal, suppose that amineral such as feldspar is extracted and usedfor a particular purpose that requires itsphysical and (or) chemical properties. Thisis not a common-variety situation regardlessof whether the feldspar is mined as an indivi­dual mineral or as granite (a stone or rock)containing several minerals such as mica andquartz in addition to the mineral feldspar.

In general, if the rock is valuable foronly an individual mineral or element such asgold, silver, feldspar, mica, etc., it is nota common - variety question and 30 USC 611does not apply; however, if the entire rockis used and the constituent elements orminerals are relatively unimportant, then 30USC 611 may apply.

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Unique Property Gives SpecialUse or Higher Price in Market Place

In U.s. Minerals Development Corp., 75 ID127~68), one of the early and importantcommon variety cases, the Board held that fora deposit to be an uncommon variety, it mustsatisfy the following criteria: (1) Thedeposi t must have a unique property, (2) Theunique property must give the deposit a dis­tinct and special value, (3) The value may befor some use to which ordinary varieties ofthe mineral cannot be put, or (4) The materialmust sell at a higher price than material inother deposits without such property issold.

Guidelines to Distinguish betweenCc:>rnrron And uncommon varieties

In MCClarty v. Secretary of the Interior,408 F2d 907, 90S-(9th Cir. 1969~the Courtset forth standards to distinguish betweencommon varieties and uncommon varieties ofmaterial, thus approving u.s. Mineral Devel­opment Corp., supra. The Cburt said at 908:

In the u.s. Minerals Development Corpora­tion case, the Secretary, impelled by theCbleman decision to breathe some life into thebuilding-stone statute, has defined guidelinesfor distinguishing between common varietiesand uncommon varieties of building stone.These guidelines, as we discern them, are (1)there must be a comparison of the mineraldeposit in question with other deposits ofsuch materials generally; (2) the mineraldeposit in question must have a unique proper­ty; (3) the unique property must give thedeposit a distinct and special value; (4) ifthe special value is for uses to which ordi­nary varieties of the mineral are put, thedeposit must have some distinct and specialvalue for such use; and (5) the distinct andspecial value must be reflected by the higherprice which the material commands in the mar­ket place.

Lower Overhead and Greater profits

In MCClarty ~ Secretary of the Interior,supra at 909, the Court suggested that thedistinct and special value of a stone may notbe measurable by a comparison with the priceof other building stones; and that the uniqueproperty of the deposit might allow lowercosts of mining and thus greater profits.

Intrinsic Factors Distinguishedfrom Extrinsic Factors

The Interior Board of Land Appeals hadheld in a number of cases that unique proper­ties that give a deposit a distinct and spe-

cial value must be inherently intrinsic to thedeposit. Extrinsic factors such as scarcity,proximity to market, value added by manufac­ture or marketing techniques and other ex­ternal factors unrelated to the deposit itselfare not counted towards giving a deposit adistinct and special value.

Immense Quantities Indicate Common Variety

In U.s. v. Coleman, supra at 603-604, theUnited States Supreme Cburt said "we believethat the Secretary of the Interior was •••correct in ruling that in view of the immensequantities of identical stone found in thearea outside the claims, the stone must beconsidered a common variety."

Stone In Question Must Be ComparedWith COOlmon varietIeS -

In U.s. v. vaughn, 56 IBLA 247 (1981), theBoard held that" it is a prerequisite for anadequate comparison that the stone in questionbe compared with deposits of common varietiesin order to determine if it has a distinctand special value reflected by a higher marketvalue."

Comparison Must Be With All DepositsRather ThanlJnCOnuno~rIeties

In U.S. v. Kaycee Bentonite Corp., 64 IBLA186, 207-209 (1982), the Board reviewed anumber of cases where it was held that thecomparison of a deposit of stone may be withall deposits, or limited to similar deposits.The Board held that the comparison should bewith all deposits generally if (1) the depositis marketable for purposes that are not typ­ical of common variety minerals, and (2) thematerial is not widespread.

Comparison Made with Stonein Immediat'""8"Reg1Oi1---

According to u.s. v. Smith, 66 IBLA 182,189 (1982), the Board held that the comparisonmay be made with other stone in the immediateregion in active quarries and exposed out­crops. If stone in exposed outcrops may beused in the comparison, one is not restrictedto only those deposits that are mined andmarketed.

Cbmparison With other Mineralson Per Unit Basi-s--

The Board in u.s. v. MCClarty, 17 IBLA 20,46 (1974) said that materials must be com­pared on a "per unit" basis rather than onvolume or quantity of material sold.

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Cbmparable Deposits Marketed by Others

Melluzzo v. Morton, 534 F2d 860 (9th Cir.1976) gives authority to prove marketabilitywhere successful marketing by others hasestablished that the claimant's undevelopedbut comparable material is marketable.

Unique Properties Distinguishedfrom High Quality Material

Even though the material on a claim is ofa better quality than other material foundgenerally in the area, the IEpartment has heldin several cases that the fact that depositsmay have characteristics superior to those ofother deposits (but do not give it special anddistinct value) does not make them an uncommonvariety so long as they are used only for thesame purposes as other deposits that are wide­ly and readily available. [U.S. v. Guzman, 81ID 685 (1974); U.S. v. Hare""D5er~ 9 IBLA 77(1973).] -----

Aggregates of Profits from Sales ofCommon and uncommon varIeties- -

In many cases a claim may contain depositsof both common and uncommon variety minerals.For example, a claim may embrace layers ofvery pure metallurgical-gra:le 1 imestone inter­bedded with layers that do not qualify asmetallurgical grade. If the claimant shouldbe necessity mine both grades and sell thelower-grade limestone for some common varietyuse, he cannot include profits from the salewith profits derived from sale of the metal­lurgical-grade limestone to show marketabil­ity. The common variety limestone must bepurchased by contract as required by 30 USC601.

In U.S. v. Lease, 6 IBLA 19, 25-26 (1972),the Board considered a case involving aggrega­tion of profits from sales of metallurgical­grade dolomite and common variety dolomite.

In U.S. v. Forsesyth, 15 IBLA 43, 59-60(1974), the Board again said that with dif­ferent grades of limestone, you cannot aggre­gate the profits of the common and uncommonvariety minerals; but instead, you must treatthe common variety limestone as waste with novalue, even if it must be mined in order toextract the uncommon variety deposit.

In U.s. v. Mansfield, 35 IBLA 95 (1978),the Board considered a case involving theaggregation of profits from several grades ofobsidian.

Gold or Other Locatable Mineralswith COrriiilcmVariety Minerals

The question of whether gold can beclaimed if it is contained in common varietymaterial such as sand and gravel was addressed

by section 3 of the Act of July 23, 1955,which provides as follows:

That nothing herein shall affect theval idi ty of any mining locationbased upon discovery of some othermineral occurring in or in associa­tion with such a deposit (of commonvariety sand, stone, etc.) ••••This provision refers to the discovery of

some locatable mineral such as gold occurringin a deposit of a common variety sand andgravel. Congress did not intend that thepresence of gold wi thin such a deposi t wouldvalidate the claim, rather, there must be adiscovery of gold within the meaning of themining laws. The fact that a mineral likegold occurred in a nonlocatable deposit ofsand and gravel would not invalidate the claimif it were otherwise valid because of thediscovery of gold under this standard. How­ever, likewise, the value of the sand andgravel would not be considered in evaluatingthe value of the gold to determine if therewas a valuable deposit of gold.

Sand and Gravel Deposits ThatHave Never Been Locatable--

Sand or gravel used as fill, subbase orballast has never been locatable. [U.s. v.Osborn (Supp on Judicial Remand), 28 IBLA 13(1976) .]

Sand and Gravel Deposits Notr::ocatable After July 23, 1955

In U.s. v. Henderson, 68 ID 26, 29-30(1961), the Department considered a sand andgravel deposit (free of caliche and otherimpurities) in which it was possible to use orsell pit-run material meeting constructionspecifications of concrete aggregate. InHenderson, supra, the Board said:

The fact that these sand and graveldeposits may have characteristicssuperior to those of other sand andgravel deposi ts does not make theman uncommon variety of sand andgravel so long as they are used onlyfor the same purposes as other de­posits which are widely and readilyavailable.If, however, such a claim was valid and

existing on July 23, 1955 and met the market­ability test from then until the present, theclaim would be valid.

The Department has consistently held thatsand and gravel deposits suitable for roadbase, asphalt-mix and ooncrete aggregate with­out expensive processing, but which are ausedonly for the same purposes as other widelyavailable, but less desirable de];Osits of sandand gravel, are common varieties. [U.S. ~Ramsta::l, A-30351 (september 24, 1965).]

76

The McCormick Case: An Uncommonvariety Sand and Gravel

In U.s. ~ McCormick, 27 IBLA 65, 68-69,83-84 (1976), the Board held that the sand andgravel deposit in question was an uncommonvariety. this is one of the very few sand andgravel deposits to ever qualify as an uncommonvariety, and for this reason should be readcarefully to develop an understanding of thetypes of properties and/or uses that make sucha mineral locatable even after July 23 1955.It should be noted in reading this case thatthe Board applied to sand and gravel many ofthe principles previously established forbuilding stone. The Board said:

We conclude the merits of the casedemand a holding that the materialis locatable. The evidence estab­lishes the following special charac­teristics of the deposit whichtranslate directly into special andsubstantial economic values: (1) Nodrilling, blasting, or ripping isrequired, (2)'No "primary" crushing(to reduce the rock to minus 15inces) is required, (3) Three offour purchaseres testified that no"secondary" crushing was required,(4) There is little or no over­burden, (5) The material is natural­ly sorted by type, no sorting orclassification is required beyondscreening to eliminate oversize, (6)The waste factor is very much lowerthan at other area pits, (7) Thematerial is naturally clean,requiring no washing, (8) Noblending of fine or coarse aggre­gates is necessary to meet specifi­cations, (9) Because the material issignificantly lighter in weight thancompeting aggregates, a ton of thesubject material will ocver a 20percent greater area, and (10) Thematerial can be used without theaddition of expensive lime or com­mercial anti-stripping agents.

Gem Stones and Gem Minerals

G:lm stone and gem minerals are discussedtogether in this section even though manyminerals are elements or minerals as U"'''''-'.L.UJ<:::U

in Pierce, supra; and therefore are neithercommon or unccmunon varieties.

G:lm stones and minerals held to beable in early cases include: (1) onyx -onyx Development Co., 38 LD 504 (1910);marble - Pacific Coast Marble Co. v. ~~·~~l~a~~

Pacific R.R. Co.,25LD 233 (1897);monds - 14 Gp. Atty, Gen, 115, 1872.

Value of Gemstones as Found onffilriiS"Rather Than 'Enhanced Value

In U.S. v. Stevens, 14 IBLA 380 (1974),'the Board determined that even though manystones will take a polish and have an enhancedvalue because of it, "it is the va1ue of thestone deposit as it is found on the claimsthat is the important fact." In other words,if a gemstone such as "chert" or "jasper" isto be an uncommon variety, it is the value ofthe stone in its uncut or unpolished statethat must be compared with other "stone forma­tions."

Obsidian is a Common Variety Mineral

In U.S. v. Mansfield, 1978, the Ibarddetermined that the ability of obsidian totake polish does not make it an uncommonvariety. In this case, it was held thatobsidian was held to be a common varietybecause it exits "in almost limitless quanti­ties."

Gemstone Permits Do NotApply Towards valIdfty""

The mining laws do not authorize the saleof permits to take or enjoy gemstones; and anysuch sales would not be considered in deter­mining the validity of a claim. [U.S. ~Stevens, 14 IBIA 380 (1973).]

Geodes Are Uncommon variety Minerals

In U.s. v. Bolinder, 28 IBLA 192 (1976),the Board held that geodes are an uncommonvariety mineral and should not be comparedwith other geode deposits but instecd sluuldbe compared with "other stone formations:'

Locatable Grades of Limestone

In U.S. v. Forsesyth, 15 IBLA 43, 59(1974), the Board upheld U.S. v. Chas. Pfizer& Co., Inc., 76 ID 331 (1969) in which lime­stone containing 95 percent or more calciumand magnesium carbonates was determined to bean uncommon variety.

Limestone Used as Concrete Aggregateor Soil AdCITITves

In u.s. v. Alaska Limestone Corp., 66 IBLA316, 324 (1982), the Ibard held that limestonedeposits cannot be located after JUly 23, 1955for use as concrete aggregate or soil addi­tives.

Limestone Used in Manufactureof Cement is Uncommon Variety

Although limestone used in the manufactureof cement is an uncommon variety, it muststill meet the requirements of discovery in-

77

eluding marketability at a profit. [U.s. ~Alaska Limestone Corp., supra at 318.]

Cinders and Other Volcanic Products

In U.S. v. Harenberg, 9 IBLA 77 (1973),the Board held that volcanic cinders used inthe manufacture of cement blocks is a commonvariety mineral.

Volcanic rock useful as a filter rock insewage treatment plants may be an uncommonvariety mineral. [U.S. v. Clark CountyGravel, Rock and Concrete COmpany;- A-31025(March 2~70).]

Soil Amendments

In U.S.v.Bunkowski, 79 ID43 (1972), itwas held that when a mineral is used as asoil amendment, it must cause a chemicalchange to the soil rather than a physicalchange.

Introduction to Clay

The most comprehensive decision concerningthe locatability of clay is undoubtedly u.s.v. Peck, 29 IBLA 357, 84 ID 137 (1977).""""()[particular significance in Ieck is the !bard'sdistinction between "common" or "ordinary"clay not considered a "valuable mineraldeposi t" and deposi ts of clay having excep­tional qualities useful for purposes for whichcommon clay cannot be used.

1. Comm::m Clay (salable):In referring to "common clay"not locatable under the mininglaws, the precedents demonstratethat clay used only for struc­tural brick, tile, and otherheavy clay products, and pressedor face brick, falls within thatclassification. They also demon­strate that clay deposits usefulonly for pottery, earthenware,or stoneware that cannot meetthe refractory and other qualitystandards for high-grade ceramicproducts, such as china, comewithin that classification.

2. EXceptional Clay (locatable):The exceptional qualities thathave been recognized as taking adeposit outside the classifica­tion of a common or ordinaryclay wi thin the meaning of themining laws are, as mentioned,clays having sufficiently highrefractoriness to meet the stan­dards for products requiringsuch special qualities. In addi­tion, certain clays with specialcharacteristics that make them

useful for particular uses, asin the oil and oil-well-drillingimustries, outside the manufac­ture of general clay-products,have been considered locatable.

The Kaycee Bentonite Case

In U.S. v. Kaycee Bentonite Corp., 64 IBLA186 (1982), the Board upheld a decision ofAdministrative Law in which JUdge Meschdeclared five mining claims null and void and125 mining claims valid because the claimscontain deposi ts of exceptional clay. JudgeMesch held that if a claimant can establishthat a deposit of bentonite is marketable forpurposes for which common clay cannot be used,the deposit is locatable. Bentonite, the"exceptional clay" in this case, is used as abinder in pelletizing taconite. Approximatelyeighty percent of the steel produced in theUni ted States is made from pellets oftaconite.

Pertinent points from Kaycee Bentoniteare: (1) Even if blending is required, ben­tonite is still an exceptional clay (64 IBLAat 217), (2) Bentonite must meet the market­ability test (64 IBLA at 217), and (3) Wide­spread minerals may be locatable.

Standards to DistiIlJuish CbmmonVarieties and Uhcommon varieties

In Massirio v. Western Hills MiningAssociation, 78 IBLA 155 (198~he Boardstated that the following standards to "dis­tinguish between common varieties and uncommonvar ieties of material" were set forth inMcClarty v. Secretary of the Interior, 408 F2d907, 908-09 (9th Cir.1969): (1) There mustbe a comparison of the mineral deposit inquestion with the other deI,Dsits of such min­erals generally, (2) The mineral deposit inquestion must have a uniqrn property, (3) Theunique property must give the deposi t a dis­tinct and special value, (4) If the specialvalue is for uses to which ordinary varietiesof the mineral are put, the deposit must havesome distinct and special value for such use,and (5) The distinct and special value must bereflected by the high price which the materialcommands in the market place, or by reducedcost or overhead so that the profit to theclaimant would be substantially more.

FEDERAL MINERAL LEASING

The Mineral Leasing Act of 1920, asamended (30 USC 181 et seq.) provides that"deposits of coal, phosphate, sodium, I,Dtas­sium, oil, oil shale, native asphalt, solidand semisolid bitumen, and bituminous rock(incluHng oil- impregnated rock or sands fromwhich oil is recoverable only by specialtreatment after the deposit is mined or quar-

78

ried) or gas, am lams containing such depos­its owned by the United States" may beacquired only through a leasing system. Forthe most up-to-date and detailed requirementsconcerning Federal leasable minerals oneshould consul t the most recent volume or Title43 of the Code of Federal Regulations.Because these regulations are under constantrevision, it is also a good practice to checkthe "CUmulative List of Sections Affected",which gives a monthly update on new regula­tions, and the "CUmulative List of PartsAffected", which appears in each issue of theFederal Register. Federal leasable mineralsare covered in the following parts of the Cbdeof Federal Regulations: Part 3100 - oil andGas Leasing; Part 3200 - Geothermal ResourcesLeasing; Part 3300 - OUter Cbntinental ShelfMinerals; Part 3400 - Coal Management; andPart 3500 - Leasing of Minerals other than theabove.

Authority - Public Domain

The basic statute for mineral leasing onpublic domain lands is the Mineral LeasingA::tof February 25, 1920 (41 Stat. 437; 30 USCSec. 181 et seq.), as amended and supple­mented.

Leasable Minerals - Public Domain

The Mineral Leasing Act of 1920, asamended, authorizes that specific mineralsshall be disposed of through a leasing system.Minerals designated as leasable under this lawinclude: 1. Phophate; 2. Native asphalt,solid and semisolid bitumen and bituminousrock including oil-impregnated rock or sandsfrom which oil is recoverable only by specialtreatment after the deposit is mined; 3. Sul­phur in the states of Louisiana and NewMexico; and 4. Chlorides, sulfates, carbon­ates, borates, silicates, or nitrates ofpotassium and sodium.

Authority - Acquired Lands

Minerals in acquired lands may be leasedpursuant to the Mineral Leasing Act forAcquired Lands (61 Stat. 913; 30 USC 351-359).This law was enacted on August 7, 1947, Sec­tion 402 of Reorganization Plan NJ. 3 of 1946(60 Stat. 1099) transferred the function ofleasing and disposal of minerals in certainacquired lands from the secretary of Agricul­ture to the secretary of the Interior.

Leasable Minerals - Acquired Lands

All minerals that now qualify as locatableminerals in public domain lands may in somecases be obtained through a mineral lease onacquired lands. Leasable Minerals in thiscategory would include gold, silver, copper,

gems, uranium, etc. Also, all mineralsdesignated by the Mineral Leasin;J lICt of 1920as leasable in public domain lands are leas­able in acquired lariis.

Filing Procedure

Application for leases or permits arefiled with the appropriate fees in the landoffice of the Bureau of Land Management of thestate in which the permits or leases aresought. When an application is received inthe land office, it is date-stamped to estab­lish priority and a serial number is assigned.The application is then copied and placed onthe public counter for review by interestedpersons. A serial page is prepared for eachapplication and is placed in the serial Regis­ter lbok in chronological order. When leasesare issued, assigned or terminated, an entrydescribing the action is made on the serialpage. A separate use township plat is pre­pared for each mineral under lease or permit.For example, all oil and gas leases in atownship are delineated on an oil and gasplat, all ooal leases in the same township aredelineated on a coal plat and all geothermalresources leases are delineated on a geother­mal resource plat.

Prospecting Permit

A prospecting permit allows the permitteean exclusive right to prospect and explorewithin a permit area to establish the exis­tence of valuable minerals. The permittee isallowed to remove only such deIDsits as neces­sary to oonduct experimental studies and mustkeep a record of all minerals removed. Aprospecting permit does not authorize miningin commercial quantities.

Term - Prospecting Permits

prospecting permits are normally issuedfor a term of two years. A phosphate permi tmay be extended for a period of four years ifcertain oonditions are met.

Preference-Right Lease Applications

Applications for a preference-right leasemust be filed in the land office not laterthan 30 days after the prospecting permitexpires.

lICreage Limitations - Acquired Lands

The amount of acquired lands that may beheld by a permittee or leasee may not exceedthe amount that may be held on publ ic domainlands under the mineral leasing laws. Permitand lease holdings on publ ic domain lands donot count against such holdings on acquiredlands.

Minerals that are currently locatableunder the ~neral Mining Law of 1872 in publicdomain lands are available only through amineral lease in acquired lariis. No person isallowed to hold more than 20,480 acres underlease and permit in anyone state. A prospec­ting permit may not exceed 2,560 acres andmust fit within an area of six miles square orwithin an area not exceeding six surveyedsections in length or width.

Term - Leases

Leases are issued for a pr irnary tenn of 20years and are subject to readjustment of termsif the lease is to be renewed. Asphalt leasesare issued for a primary term of 10 years.Hardrock mineral leases for acquired landshave a term that is established by the BLM but ­canoot exceed 20 years.

SAIABIE MINERALS IN BlJRE.llliOF I1\ND MANAGEMEIiIT-AIlUNISTERED IANIE

Authority

The Materials Act of July 31, 1947 (61Stat. 681), amended by the Acts of July 23,1955 (PL-167i 69 stat. 367) and September 28,1962 (PL-87-713), authorized that certainmineral materials be disposed either throUJh acontract-of-sale or a free-use permit. Thisgroup of mineral materials, commonly koown as"salable minerals" includes, but is notlimited to, petrified woed and oornrnon varie­ties of sand, stone, gravel, purnicite, cin­ders, and clay on public lands of the unitedStates, 30 usc 601 (1976).

Effect on Minin;J Claims andother SUrface Uses

Mineral-material disIDsals are not madewhere there are valid existing claims. Anysubsequent mining location or mineral leasecovering lands under a contract-of-sale formineral materials is subject to the out­standing oontract-of-sale. The United Statesreserves the right to continue to use thesurface of lands under contract-of-sale forleases, licenses and permits concerning otherresources i however, these subsequent leasesmust not interfere with the extraction orremoval of the mineral material. Removal ofmineral materials from the public lariis with­out authorization is an act of trespass.

Cbrrmunity pits

The regulations (4 CFR 3604.1) provide forthe establishment of oornrnunity pits to be usedby the general public to remove small amountsof material after obtaining a nonexclusivepermit from the district manager of the Bureauof Larii ManaJEment. A fee is charged for each

79

cubic yard or ton of gravel removed plus anamount necessary to reclaim the site upondepletion of the pit.

Corrmon U3e Areas

Common use areas, like community pits, areestablished for nonexclusive disposals ofmineral materials where the removal ofmaterials would cause only a negligible sur­face disturbance. 43 CFR 3604.1.

Appraisal of Mineral Materials

Mineral materials are not sold at lessthan the appraised value. Also, a reappraisalis necessary every two years. 43 CFR 3610.1­2.

Noncompetitive sales

Noncompetitive sales may be made where itis impracticable to obtain competition and itis in the public interest. Individual sales,not to exceed 100,000 cubic yards may be madewithout advertising or calling for bids. '!hetotal aggregate of sales to an individual mustnot exceed 200,000 cubic yards in anyonestate during a twelve month period. [43 CFR3610.2-1.] The term of contract for noncom­petitive sales is not to exceed five years,excluding extension and removal periods. 43Cr'R 3610.2-4.

Competitive sales

All sales are made through competitivebidding unless excluded for the reasons above.Sales are advertised in a newspaper of generalcirculation in the area where the material islocated. A notice of sale is published once aweek for two consecutive weeks giving thelocation of the lands, the material offered,type of materials, quantities, appraised priceand the procedure for bidding. Written sealedbids, oral bids or both may be required, to­gether with a bid deposi t of not less than 10percent of the appraised value of the mineralmaterials. The contract is awarded to thehighest qualified bidder. The term for com­petitive contracts is not to exceed 10 years,excluding extension or removal periods. 43­CFR 3610.3.

Free-use Permits

Free-use permits are issued for a periodnot to exceed one year; however, a maximumterm of 10 years is allowed for governmentagencies and municipalities. Material acquiredunder a free-use permit must be for the per­mittee's own use and may not be traded orsold. '!here is no limitation on the number ofpermits or the amount or value of the materialif the permit is issued to a gooernment agencyor municipality for use on a public project.

A free-use permit issued to a ron-profit asso­ciation or corporation must not allow disposalof more than 5,000 cubic yards in any periodof twelve consecutive months. [43 CFR3621.1.]

Mining Claims and Leases areSUbj ect to Cbntracts

Lands covered by material-sale contractsor free-use permits are subject to locationand entry under the mining and mineral leasinglaws. [U.S. v. McClarty, 81 ID 472 (1974).]IDwever the regulations in 43 CFR 3601.1-2(c)state that "any person that has a subsequentsettlement, location, lease, sale or otherappropriation under the general land laws,including the mineral leasing and mining lawon lands covered by a material-sale contractor free-use permit, shall be subject to theexisting use authorization."

SAIABLE MINERAIS INU.S. FOREST SERVICE-AI11INISTERED IANffi

(36 CFR 251.4)

AuthorityMineral materials are disposed of from the

N3.tional Fbrest System under the authority ofthe Act of July 31, 1947 (61 Stat. 681), asamended by the Act of August 31, 1950 (64Stat. 571), and the Act of July 23, 1955 (69Stat. 367; 30 USC 601-603) and pursuant to theAct of June 11, 1960 (74 Stat. 205). TheFbrest Ranger may dispose of common varietiesof sand, stone, gravel, pumice, pumicite,cinders and clay.

Free U3e

All mineral material must be appraised andsold at not less than the appraised value,except material disposed of to Federal orState agencies, municipalities or non-profitorganizations. These agencies and organiza­tions may receive the material without charge,provided the materials are not used for com­mercial purposes or resale and provided thesite is reclaimed to proouctive use•.

If the appraised value of the materialexceeds $1,000, it must be sold to the highestbidder at public auction. Notice of sale mustbe published once each week for four consecu­tive weeks in a newspaper having general cir­culation in the county in which the materialis located. The competitive sale may be bysealed bid or auction.

Appraised Value Less than $1,000

If the appraised value is $1,000 or less,the material may be sold to a qualifiedappl icant by Special Use Permit; however, nomore than $1,000 worth of materials may besold to anyone applicant in anyone area inanyone period of 12 consecutive months.

80

Mining Industrial Mineralson Arizona state Trust Land

El:lward C. SpaldingArizona State Land Department

1624 W. AdamsPhoenix, NZ 85007

are geographically distributed as shown inTable 2.

Cbconino

Pima

Apache, Cbconioo, Maricopa,M:>have, Pima, Pinal, Yuma

CDUNTY or COUNTIES

Maricopa, Pinal

Apache, Cbconino

Building Stone

sand and Gravel

Clay

IEcOUj;Dsed Granite

(DMM)DITY

Cinders

(DMM)DITY CDUNTY or COUNTIES--------Limestone/Marble Apache, Cbchise, Gila, Pima,

Pinal, Yavapai

Gypsun M::Jhave, pinal, Yavapai

Zeolites Cbchise, Graham

Funice Yavapai

Bentonite Apache

Building stone Cbconino, M::Jhave

Mica M::Jhave

Clay Pima

Magnetite sands Pinal

Feldspar Maricopa

Slate Maricopa

Tab~e 2. Distribution by county of common industrial­mineral materials being mined or quarried from Trustlands by private concerns.

Tab~e 1. Distribution by county of industrialminerals under state lease, ~isted in decreasing orderof number of leases.

The mechanics of obtaining a mineral leaseor mineral-materials sales agreement from theLand Department will not be dealt with here.SOme comments, however, should be made con­cerning certain aspects of the applicationprocess. Lease- and sales-agreement applica­tions have a number of things in common in­cluding (1) the requirement for archaeological

81

The mineral estate of Arizona's StateTrust lands, which are administered by theState Land Department for the benef i t of thecommon schools and 14 other beneficiaries,totals more than 10.5 million acres, or almost15 percent of the State's entire area. Trustlands exist in all 15 of the State's counties,wi th the most and least acreage found in Yava­pai and Gila Cbunties, respectively.

Revenues derived from the Trust mineralestate include royalties, rentals, and fees.In Fiscal Year 1983-84, these revenues amount­ed to $4.2 million, or 13.5 percent of allincome received by the '!rust during this peri­od. Industrial minerals, led by sand andgravel, contributed $1.1 million from 82 ac­tive properties.

The right to mine and ship minerals fromState Trust lands is acquired in one of twoways, by mineral lease or by mineral-materialssales agreement. locatable mineral depositssuch as gypsum or zeol i tes are leasable, butcommon mineral materials such as decomposedgranite fall in the sales-agreement category.

The department has about 650 mineralleases on its active rolls, of which 130 arefor industrial minerals. A breakdown of these130 leases by commodity is as follows: lime­stone/marble (57), gypsum (21), zeolites (13),pumice (10), bentonite (8), building or decor­ative stone (6), mica (6), clay (5), magnetitesands (2), feldspar (1), and slate (1). Lessthan 28 percent of these leases have ever paidproduction royalties to the Trust. Many ofthe nonproductive leases are being held forreserve purposes, but others lack developmentcapital or markets. In Fiscal year 1983-84,leases accounted for only 2.7 percent of totalindustrial-mineral income.

The department holds 310 mineral-materialssales agreements: 241 with the Arizona De­partment of Transportation, 30 with othergovernment agencies, and 39 with private con­cerns. Sand-and-gravel deposits and highwayconstruction materials make up the bulk of the310 sales agreements: other commodities in­clude common clays, decomposed granite, cin­ders, and building stone.

Leases for industrial minerals cover 10 ofArizona's 15 counties. Table 1 shows thegeographic distribution of these leases byccmnodity.

Common mineral materials being mined orquarried on Trust lands by private concerns

clearance, (2) input from the Game & FishDepartment and other State, county, and occa­sionally, city agencies, and (3) an approvedplan of operation. Both types of contractsrequire the posting of a restoration and dam­age bond.

There are several major differences be­tween leases and sales agreements. Leasesfor industrial minerals are based upon 20-acremineral claims that conform to the public landsurvey and require proof of discovery of avaluable mineral deposit for each claim. Amineral lease extends for up to 20 years, witha preferred right to renewal. unlike a salesagreement, a lease does not require publicauction. Sales agreements are active for up to10 years, but are not renewable. Sales agree­ments also require a minimum annual guarantee,whereas leases do not. By statute, productionroyalties for mineral leases are 5 percent ofthe net value of the extracted materials.

Increased concern over the impact ofmining and quarrying operations on the envi­ronment, plus a desire to increase the per­centage of royalty-paying operations, has ledthe Land Department to take a stronger posi­tion on issuing leases and sales agreements.Applicants for mineral leases must submit muchmore information than previously required.Because the department will use this informa­tion to make a preliminary economic evaluationof a given property, items such as estimatedreserves, projected start-up date, productionrate, costs, and marketabili ty should be in­cluded.

The Land Department's files contain aconsiderable amount of information that couldbe helpful to anyone searching for industrial­mineral deposits in Arizona. A visi t to thedepartment's Nonrenewable Resources and Min­erals Section, at 1624 W. Adams St., phoenix,Ariz., could prove to be worthwhile.

82

Minerals and tIealth: The Asbestos Problem

MalcoJm I«:>ssu.s. Geological Survey, MS 959

Reston, VA 22092

ABSTRACT

Of the six forms of asbestos, only threehave been used to any significant extent incommerce. These are chrysotile, crocidolite,and amosite. Between 1870 and 1980, approxi­mately 100 million tonnes of asbestos wasmined worldwide, of which more than 90 milliontonnes was the chrysotile variety, about 2.7million tonnes the crocidolite variety, andabout 2.2 million tonnes the amosite variety.

The three principal diseases related toasbestos exposure are (1) lung cancer, (2)cancer of the,pleural and peritoneal membranes(mesothelioma), and (3) asbestosis, a condi­tion in which the lung tissue becomes fibrousand thus loses its ability to function. Thesediseases, hoWever, are not equally prevalentin the various groups of asbestos workers thathave been studied: the amount and type ofdisease depend on the duration of exposure,the intensity of exposure, and particularly,the type or types of asbestos to which theindividual has been exposed.

Lung cancer is caused by exposure tochrysotile, amosite, and crocidolite asbestos;however, increased risk of this disease isusually found only in those who also smoke.Asbestosis is caused by prolonged exposure toall forms of asbestos, whereas mesothelioma isprincipally caused by exposure to crocidoliteasbestos. There is good evidence that chryso­tile asbestos does not cause any significantamount of mesothelioma mortality, even aftervery heavy exposure. The common nonasbes­tiform amphibole minerals, cummingtonite,grunerite, tremolite, anthophyllite, andactinolite, which are often defined as "asbes­tos" for regulatory purposes, have not beenshown to cause disease in miners.

Chrysotile asbestos, which accounts forabout 95 percent of the asbestos used in theUnited States, has been shown by extensiveCanadian studies to be safe when exposures donot exceed 1 fiber per cm3 for the workinglifetime. Chrysotile dust levels found \nbuildings rarely exceed 0.001 fibers per cm •Such dust concentrations will have no measur­able health effect on the building occupants.

Present and future controls of mineralsdefined as "asbestos" and removal of asbestosfrom buildings and homes may cost many bil­lions of dollars. Much of this expense isunnecessary and even counterproductive. As-

83

bestos abatement could in fact produce aheal th risk to those exposed to dusts duringand after removal operations. OVerly restric­tive controls could force the use of poor ordangerous substitutes, and could greatlyaffect the hard-rock mining industry.

INTRODUCTION

In our continuing search for new resourcesof industrial minerals and efforts for ex­panding their use, the possible health hazardrelated to exposure to mineral dusts has be­come an important factor in deciding whichminerals can be safely mined, processed, andincorporated into commercial products.

A large number of exper iments have beenperformed in which a variety of minerals andinorganic substances (such as fiber glass)have been implanted into the tissues of liveanimals. Often these animals developed can­cer. These experiments strongly suggest thatif ground up rock were similarly administered,a significant number of animals would developtumors. The ability is at hand to "prove"that the Earth is a carcinogen!

The prevailing cancer dogma in the Unitedstates espouses the "no threshold" theory forcancer genesis. Influential health special­ists have repeatedly said that because no oneknows the minimum amount of a carcinogen re­quired to initiate the growth of a cancertumor, it must be assumed that any amount ofany carcinogen is unsafe. The U.S. publ ic hasbeen led to believe that exposure to just onemolecule of a chemical carcinogen can causecancer. In regard to exposure to asbestos,this belief has become a paradigm to the ef­fect that "one asbestos fiber can kill you."

Unless we decide that living on a carcino­genic earth is unacceptable and move else­where, a perception and an observation must bereconciled: (1) carcinogens produced by man,even in trace amounts, are responsible formost human cancer, and (2) carcinogens pro­duced naturally are ubiquitous in our environ­ment. The public has not been made aware thata large percentage of the carcinogens takeninto the human body are naturally occurringchemicals found in foods, beverages, and to­bacco. Examples of some of these carcinogensare safrole, estragole, and methyleugenol inedible plants; piperine in black pepper; hy­drazines in edible mushrooms; furocoumarins in

celery and parsnips; aflatoxins in corn,grain, nuts, cheese, peanut butter, bread andfruit; solanine and chaconine in potatoes;caffeic acid in coffee; theobromine in choco­late and tea; acetaldehyde, an oxidation prod­uct of ethyl alcohol, in alcoholic beverages;allyl isothiocyanate in mustard and horserad­ish; and nitrosamines fonned from nitrates andnitrites found in beets, celery, lettuce,spinach, radishes, and rhubarb (Ames, 1983,1984). The amount of these chemicals ingestedby man is not trivial; for example, the com~on

commercial mushroom Agaricus bisporus contaInsagaritine, a hydroxymethyl phenylhydrazinederivative, in a concentration of 3,000 partsper million or 45 mg per mushroom (Ames, 1984,p. 757)

In contrast to naturally occurring chemi­cals, man-made chemicals, which sometimes con­taminate foods, air, and water, make up arelatively small portion of the total humanintake of carcinogens. For example, Ames(1983, p. 1258) estimates that the human in­take of naturally occurring pesticides (chemi­cals formed by plants themselves to fightinsects, fungi, etc.) is at least 10,000 timesgreater than the human intake of man-made pes­ticides. Doll (1983) estimates that avoidanceof tobacco smoke and alcoholic drinks wouldreduce cancer mortality by 38 percent, whereasavoidance of man-made carcinogens contami­nating foods, air, and water would reducecancer mortality by less than 1 percent.

The perception that small amounts of man­made chemicals are the major cause of humancancer mortality is blatantly false, as provenby a massive amount of epidemiological dataand summarized by I:bll and Peto (1981). Yetthis perception, exemplified by statementssuch as "one fiber or molecule can kill you,"is so strong in the minds of the U.S. publicthat it will take a massive effort by respon­sible scientists and journalists to change it.Bruce Ames, Sir Richard I:bll, Richard Peto,John Higginson, John Cairns, Gio Gori, JohnWeisburger, Ernst Wynder, Edith Efron, andMichael Bennett are some who are leading theway in bringing good science and good journal­ism to the public's attention.

In the following sections, I will summa­rize the specialized topic "asbestos andhealth" but in context with the broader prob-, b . ,lem of human carcinogenesis and the pu 11C sperception of the causes of cancer. Thissummary is based on a long review paper p~b­

lished previously (Ross, 1984); for d~talls

and reference citations, the reader IS re­ferred to this publication.

As I will try to show, the asbestos prob­lem is not restricted to the mining, milling,and use of commercial asbestos; it includesmuch of the mining industry, as well as thegreatly expanding fiber and composites indus­try.

84

THE ASBES1DS PROBLEM

The widespread use of amphibole and ser­pentine asbestos by industrial society foruses such as brake and clutch facings, elec­trical and heat insulation, fireproofing mate­rials, cement water pipe, tiles, filters,packings, and construction materials has con­tributed greatly to human safety and conve­nience. Yet, while our society was accruingthese very tang ible benef i ts, many asbestosworkers were dying of asbestosis, lung cancer,and mesothelioma.

The hazards of certain forms of asbestosunder certain conditions have been so greatthat several countries have taken extraordi­nary actions to greatly reduce or even bantheir use. Recent experiments with animalsdemonstrate that the commercial asbestos min­erals, as well as other fibrous materials, cancause tumors to form when the fibrous parti­cles are implanted within the pleural tissue.These experiments have convinced some healthspecialists that asbestos-related diseases canbe caused by many types of elongate particles:the mineral type, according to these healthspecialists, is not the important factor inthe etiology of disease, but rather the sizeand shape of the particles that enter thehuman body.

At present, the most widely used defini­tion of asbestos in the United States is takenfrom the notice of proposed rule-making for"occupational Exposure to Asbestos," publishedin the Federal Register on oct. 9, 1975 (p.47652-47660) by the U.S. occupational Safetyand Health Administration (OSHA). In thisnotice, the naturally occurring amphiboleminerals amosite, crocidolite, anthophyllite,tremolite, and actinolite, and the serpentinemineral chrysotile are classified as asbestosif the individual crystallites or crystalfragments have the following dimensions: alength greater than 5 microns, a maximum diam­eter less than 5 microns, and a length-to­diameter ratio of three or greater. Any prod­uct containing any of these minerals in thissize range is also defined as asbestos.

The crushing and milling of any rock usu­ally produces some mineral particles that arewithin the size range specified in the OSHArules. Thus, these regulations present aformidable problem to those analyzing forasbestos minerals in the multitude of mate­rials and products in which they may be foundin some amount. Not only must the size andshape of the asbestos particles be determined,but also an exact mineral identification mustbe made. A wide variety of amphiboles isfound in many types of common rocks; many ofthese amphiboles might be considered asbestosdepending upon the professional training ofthe person involved in their study and themethods used in mineral characterization.

If the definition of asbestos from thepoint of view of a health hazard does includethe common nonfibrous forms of amphibole;particularly the hornblende and cummingtonitevarieties, then we must recognize that asbes­tos is present in significant amounts in manytypes of igneous and metamorphic rocks cover­ing perhaps 30 to 40 percent of the unitedstates. Rocks within the serpentine belts;rocks within the metamorphic belts that arehigher in grade than the greenschist facies,including amphiboli tes and many gneissicrocks; and amphibole-bearing igneous rockssuch as diabase, basalt, trap rock, and gran­ite would be considered asbestos bearing.Many iron formations and copper deposits wouldbe asbestos bearing, including deposits in thelargest open-pit mine in the world at Bingham,Utah. Asbestos regulations would thus pertainto many of our country's mining operations,including much of the construction industryand its quarrying operations for concreteaggregate, dimension stone, road metal, rail­road ballast, riprap, and the like. The as­bestos regulations would also pertain to theceramic, paint, and cement industries, and tomany other areas of endeavor where silicateminerals are used.

GEOUX;ICAL OCCURRENCE OF COMMERCIAL ASBESTOS

Many minerals, including the amphibolesand some serpentines, are described variouslyas fibrous, asbestiform, acicular, filiform,or prismatic; these terms suggest an elongatehabit. Although such minerals are extremelycommon, only in a relatively few places dothey have physical and chemical propertiesthat make them valuable as commercial asbes­tos. IDcally, amphibole minerals may show anasbestiform habit, for example, in vein fil­lings and in areas of secondary alteration,but usually they do not appear in sufficientquantity to be profitably exploited.

Deposits of commercial asbestos are foundin four types of rocks:

(a) Type I - alpine-type ultramaficrocks, including ophiolites (chryso­tile, anthophyllite, and tremoli te);

(b) Type I! - strati;Eorm ultramafic in­trusions (chrysotile and tremolite);

(c) Type II! -serpentinized limestone(chrysotile); and

(d) Type IV - banded ironstones(amosite and crocidolite).

Type I deposits are by far the most impor­tant and probably account for more than 85percent of the asbestos ever mined. The mostimportant Type I deposits are those in QuebecProvince, canada and in the Ural Mountains ofthe Soviet Union.

Type I! deposits are found mostly in SouthAfrica, swaziland, and Zimbabwe; these furnish

85

mostly chrysotileare small; the mostcated near Globe, Arizonaarea of the Transvaal ProvAfrica. Type IV deposits arePrecambrian banded ironstonesTransvaal and Cape Provinces of South Atricaand in Western Australia. Only the SouthAfrican deposi ts are still in production. Acomplete review of the geological occurrencesof commercial asbestos is given by Ross(1981).

Since the first recorded use of asbestosby stone Age man, more than 100 million tonnesof asbestos have been mined throughout theworld, of which more than 90 percent waschrysotile and more than 5 percent wascrocidolite and amosite. Nearly 40 milliontonnes of this total world production waschrysotile mined in Quebec Province near thetowns of Thetford Mines and Asbestos. Thetotal production of anthophyllite asbestos todate is probably no more than 400,000 tonnes,350,000 tonnes being produced by Finlandalone. The production of tremolite asbestoshas been sporadic, and it has been mined invarious parts of the world for short periodsof time. The total production to date of thisform of asbestos is probably no more than afew thousand tonnes. Commercial exploitationof actinolite asbestos is practically unknown.

The world asbestos production for 1981 was4.34 million tonnes; the U.S.S.R. led with48.5 percent and Canada was second with 25.9percent of the world's output (Clifton, 1983).Both countries mine mostly chrysotile asbes­tos, and most of this comes from the UralMountains and Quebec Province.

THE NATURE OF ASBESTOS RELATED DISEASE

The three principal diseases related toasbestos are (1) lung cancer, (2) cancer ofthe pleural and peritoneal membranes(mesothelioma), and (3) asbestosis, a condi­tion in which the lung tissue becomes fibrousand thus loses its ability to function. Thesediseases, however, are not equally prevalentin the various groups of asbestos workers thathave been studied: the amount and type ofdisease depends on the duration of exposure,the intensity of exposure, and particularly,the type or types of asbestos to which theindividual has been exposed.

Chrysotile or "White" Asbestos

Chrysotile asbestos, sometimes referred toin the trade as "white" asbestos, is the formthat is usually used in the United States - aswall coatings, in brake linings, as pipe insu­lation, and in other uses. About 95 percentof the asbestos in in-place products in theUnited States is the chrysotile variety, and alarge percentage of this was mined and milled

in Quebec Province, Canada. Epidemiologicalstldies of the chrysotile asbestos miners andmillers of Quebec undertaken by medical re­searchers in canada show that, for men exposedfor more than 20 years to chrysotile dustaveraging 20 fibers/cm3, the total mortality(from all causes) was less than expected (620observed deaths, 659 expected deaths). Therisk of lung cancer was slightly increased:48 deaths observed, 42 expected. Exposures to20 fibers/cm3 are an order of magnitudegreater than those experienced now ~which aregenerally less than 2 fibers/em); thus,chrysotile miners working a lifetime underthese present dust levels should not be ex­pected to suffer any measurable excess cancer.A similar mortali ty picture is reported forItalian chrysotile miners and millers.

Mesothelioma incidence among those workingonly with chrysotile asbestos is very low.Thus far, about 16 deaths due to this diseasehave been reported among chrysotile asbestosminers and millers and one among chrysotiletrades workers. In addi tion, 6 deaths amongsons and daughters of chrysotile miners andmillers and 2 among others living in chryso­tile asbestos-mining localities have beenreported as being due to mesothelioma.

Four epidemiological studies of the femaleresidents of the Quebec chrysotile-mininglocalities show no statistically significantevidence that their lifelong exposure to as­bestos dust from the nearby mines and millshas caused excess disease.

Crocidolite or "Blue" Asbestos

Crocidolite, usually referred to in thetrade as "blue" asbestos, was first importedinto the United States in 1911 or 1912. By1930, 35,000 short tons of crude blue fiberhad entered the country, and by 1946, an addi­tional 21,000 tons had been imported. Inaddi tion to these imports, much crocidoli tehas come into the United states as manufac­tured products, such as yarns, tapes, and pipecoverings. Almost all of the importedcrocidolite has come from SOuth Africa.

Epidemiological studies of groups thatworked only with crocidolite asbestos showthat rather short periods of exposure, or evenrelatively light exposure, cause excessivemortality due to lung cancer, mesothelioma,and asbestosis. This is evident not only inthose exposed to crocidolite during gas-maskfabrication and building construction, butalso in those employed in the crocidolitemines.

There are only two mining regions in theworld where mesothelioma is a statisticallysignificant cause of death. These are thecrocidolite-mining districts of cape Province,South Africa and of Wittenoom, Western Austra­lia. Prevalence studies in Cape Provincereport that at least 278 persons have died of

86

mesothel ioma as a resul t of exposure tocrocidolite; 161 of these persons worked inthe mines and mills and 117 others lived near,the mines, but were not employed in theasbestos industry. .

Thirty-one men who had worked in the smallcrocidolite industry (total production:155,000 tonnes) at Wittenoom, Western Austra­lia, have died of mesothelioma. Of these, 13had worked for less than 12 months and 9 hadhad light to medium exposure to blue asbestos.Sixty miners and millers at Wittenoom havedied of lung cancer; 34 of these men hadworked in the industry for less than 12 monthsand 19 had had light to medium exposure to thecrocidolite dust. In addition to this occupa­tionally related mortality, 6 others who livednear, but did not work in, the mines or millshave died of mesothelioma.

.Mlosite or "Brown" Asbestos

All amosite asbestos comes from theTransvaal Province of South Africa, whereapproximately 2.2 million tonnes were minedbetween 1917 and 1979. rm[Ortation of amositeinto the United states started in the 1930'S.

Two complete epidemiolog ical studies ofasbestos trades workers exposed mainly toamosite asbestos have been published. Theincidence of asbestos-associated disease inthese two groups of men formerly employed atfactories in rondon, England and Paterson, ~wJersey was excessive, there being an 18.4percent lung-cancer mortality (117 cases), 2.8percent mesothelioma mortality (8 cases), and4.2 percent asbestosis mortality (27 cases).Only prevalence studies have been made ofamosite miners and millers; 2 individuals havedied of mesothelioma. One resident of anamosite-mining district has been reported ashaving died of this disease.

The rock-forming amphibole mineralsgrunerite and cummingtonite, which areisostructural and chemically similar toamosite, are considered (incorrectly) by someto be forms of asbestos. Health studies ofminers working ores that contain theseminerals as gangue, for example, the Ibmestakegold mines and the Reserve iron-ore miners, donot show any indication of asbestos-relatedmortality.

Anthophyllite Asbestos

This form of asbestos has been mined spo­radically in many localities, but the onlymajor production has been at Paakkila, Fin­land, where approximately 350,000 tonnes wasmined between 1918 and 1975. The only healthstudy of individuals ex[Osed predominantly toanthophyllite asbestos is that of the Paakkilaminers. This group showed a 67% excess oflung cancer and a large mortali ty due to tu­berculosis and asbestosis. There were no

deaths from mesothelioma. Becauseanthophyllite was and is used so little incommerce, no additional health studies appearto be possible except for follow-up studies ofthe Paakkila miners.

DISCUSSION

'!he Relative Hazards of the Asbestos Minerals

Must the use of all commercial asbestos bestopped? The answer is an emphatic no, butwith qualifications that are presented here.

Nonoccupational exposure to chrysotileasbestos, despite its wide dissemination inurban environments throughout the world, hasnot been shown by epidemiological studies tobe a significant health hazard. If it were,the women of Thetford Mines and Asbestos,Quebec, where more than 40 million tonnes ofchrysotile asbestos has been mined, would bedying of asbestos-related diseases. '!hey arenot. Health studies accomplished in Canadashow that populations can safely breathe airand drink water that contains significantamounts of chrysotile fiber. These studiesalso suggest that there is a "threshold" valueof chrysotile asbestos exposure below which nomeasurable health effects will occur.

'!he same fiber dose-disease response rela­tionships observed for chrysotile asbestos donot hold for crocidolite asbestos. Healthstudies of those exposed to crocidolite showit to be much more hazardous than chrysotile.lib study has been reported, comparable to thatmade for chrysotile, which would indicate whata safe level of exposure to crocidolite mightbe. The danger of crocidolite dust is partic­ularly emphasized by the many mesotheliomadeaths occurring among the residents of thecrocidolite-mining districts of cape Province,South Africa whose only exposure was in anonoccupational setting. Such mortality ispractically unknown among residents of thechrysotile-mining localities of QuebecProvince.

The hazards of amosite asbestos are moredifficult to assess. The amosite factoryemployees of rondon, England and Paterson, NewJersey, who generally worked under very dustyconditions, have experienced a great deal ofexcess mortality due to lung cancer, asbes­tosis, and mesothelioma. In contrast to thesefactory workers, amosite miners and millers,at least wi th regard to mesothelioma, do notappear to be at much risk.

The fear caused by alarmist statementssuch as "one fiber can kill you" and by themuch exaggerated predictions of the amount ofasbestos-related mortality expected in thenext 20 or 30 years has generated great polit­icar pressure to remove asbestos from ourenvironment and to reduce greatly or even stopits use. An example of this is the concertedeffort in several industrial nations, includ-

ing the United States, to remove asbestos fromsc~ools, public buildings, homes, ships, ap­plIances, and so forth. This is being done,even though most asbestos in the united Statesis of the chrysotile variety and even thoughasbestos dust levels in schools, public build­ings, and city streets are much lower thanthose found in chrysotile-mining communities,~here little asbestos-related disease appearsIn the nonoccupationally exposed residents.The impetus for these costly removals andappliance recalls (hair dryers, for example)apparently comes from propagandizing of the"one-fiber-can-kill-you" concept. lIbt only isthis program costly, but it could also bedangerous if the removal of blue asbestos isnot accomplished with great care. In mostcases, asbestos coatings and insulation, wherenecessary, can be repaired at no risk and at afraction of the cost of complete removal.

Substitutes for Asbestos

If all use of asbestos were to be d iscon­tinued, substitutes would have to be developedto meet many diverse requirements for mater­ials, such as nonflammability, high strength,flexibility, reasonable cost, and safety.With respect to safety, the substitutes mustnot induce disease in those exposed to themand also must not endanger lives in other waysby having inferior strength or durability,increased flammability, or other undesirablecharacteristics. A good substitute must nothave so high a cost that it forces the use ofan inadequate replacement. Fbssible problemscan occur with substitutes, for example, withthe replacement of chrysotile asbestos indrum-brake linings. The chance of increasedautomobile accidents due to a possibly infe­rior substitute material must be weighedagainst the probability of anyone being harmedby the small amounts of chrysotile asbestosemitted from drum brakes. The health effectsof emissions from substitute brake liningsmust also be considered.

The requirements of strength and flexi­bility make it necessary that asbestos substi­tutes be fibrous. Generally, the thinner andlonger the fibers, the stronger, more flex­ible, and useful they are; however, fiberslonger than 4 microns and less than 1.5microns in diameter are capable of producingmalignant neoplasms when implanted into thepleura of rats. Test fibers used in thesestudies have included aluminum oxide, fiber­glass, wollastonite, sil icon carbide,dawsonite and potassium octatitanate.

Man-made Mineral Fibers

In addition to the very common exposure ofman to naturally occurring fibrous minerals,he is also exposed to many different types ofsynthetically made fibers. More and more of

these substances are being developed each yearby the greatly expanding fiber and compositesindustries. Our knowledge of the health ef­fects of most of these fibers is minuscule ornonexistent. The health effects of thoseexposed to man-made vitreous fibers, however,have been studied intensively and statistical­ly significant studies are just now beingreported. These glassy fibers, usually refer­red to as man-made mineral fibers (MMMF), in­clude slag wool, rock wool, glass wool, fiber­glass, and continuous-filament products. Twoseparate reports, one of 25,146 workers at 13plants in Europe (Saracci and others, 1984),and one of 16,730 workers at 17 plants in theUnited states (Enterline and Marsh, 1985),have just been published or are about to bepublished. Table 1 gives a summary of thelung-cancer mortality for male workers in theEuropean and United States MMMF industries wholived at least 30 years since first exposure.A statistically significant excess of lungcancer (52 percent) is seen in these MMMFworkers. Ex~sure was generally less than 1fiber per cm and most commonly in the rangeof 0.01 to 0.1 fibers per cm3• In contrast,the Quebec chrysotile asbestos miners andmillers with at least 20 years service in theindustry and exposed to between 10 and 21fibers per em3 showed an excess of lung cancerof 12 percent. (Ross, 1984, p. 93).

Table 1. Lung-cancer mortality, males, atleast 30 Years observation since first employ­ment in MMMF industry.

ruNG CANCER---EUROPE ill ~"AcroRIES) (Observed) (EXpected) (Excess)

IbCk \'POl 11 5.7 93%

Glass \'POl 4 2.6 54%Continuous filament 2 0.6 233%

subtotal 17 B:9 9I%

UNITED STATES .Dl. ~"AcroRIES) (Observed) (Expected) (Excess)

Glass wool 47 36.0 31%Slag \'POl 45 28.1 60%Ibck \'POl 14 8.1 73%

Subtotal 106 7'2.2 47%

1UTALS: 123 81.1 52%

Nonasbestiform Bock-Forming Amphiboles

Some health and regulatory specialistsclassify the common rock-forming amphibolesgrunerite, cummingtonite, actinolite,tremolite, and anthophyllite as asbestos eventhoU]h they do not possess the physical prop­erties requisite to be valuable commercially.Such a classification has been made in thecase of taconite mining by the courts (U.S.District Court for Minnesota, 380 F. Supp. 11)and by the U.S. Environmental ProtectionlIgency (Reserve Mining vs. EPA, U.S. Court ofAppeals Eighth Circuit, March 14, 1975). Inthe latter case, the U.S. Environmental pro-

88

tection lIgency (EPA) sued to prevent theReserve Mining Co. from dumping taconite tail­ings into lake SUperior because of the percep­tion that these tailings contai.n "amositeasbestos" and thus constitute a threat topublic health. For a complete review of thecase see 514 Federal Reporter, 2nd series,492-542, 1975; and 256 Northwestern Reporter,2nd series, 808-852, 1977.

The possible health effects of exposureto rock dust containing one or more of themany amphibole minerals is an important issue.Amphiboles are contained within the gangue(waste rock) of many hard-rock mines: gold,vermiculite, talc, iron ore, crushed stone andaggregate, copper, etc. Certainly control ofmost dust, regardless of the mineral content,is necessary because past heavy exposure todusts containing crystalline silica (SiO 2)'slate, coal, talc, and radioactive mineralshave caused significant disease. Unusuallytight control of amphibole-mineral particles,however, such as that proposed by the NationalInsti tute for OCcupational safety and Health(NIOSH) in 1976 for asbestos fibers (0.1fibers per cm3), could stop major mining inthe United States.

several epidemiological studies have beenperformed on hard-rock miners who were exposedto noncommercial amphibole dusts. Q1e exampleis a cohort of gold miners at the HomestakeGold Mine, Lead, South Dakota, who were ex­posed to rock dust containing very significantamounts of amphibole belonging to thecummingtonite-grunerite series. The 861observed deaths included 43 lung-cancer deaths(43 expected) and no mesothelioma deaths.Nonmalignant respiratory disease due to quartzdust, however, was excessive. This cohortthus showed no evidence of mortality thatcould be related to amphibole dust (David P.Brown and others, International Symposium,Chapel Hill, North Carolina, April 5, 1984,unpublished preprint). Studies of Reservetaconite (iron-ore) miners who were exposed tocummingtonite amfhibole contained in the minedusts also show no amphibole-related disease.Of the 298 deaths (344 expected), there were15 lung-cancer deaths; 18 were expected.There were three excess deaths due to pneumo­coniosis, perhaps due to quartz dust (Ross,1984, p. 75). Despite no indication ofasbestos-related disease in these miners, theReserve Mining Company was required by theU.S. Courts (see above) to spend $300 millionto build an inland dump site for waste rock.

CCMMENTARY

The "no-threshold" cancer dogma that hasbeen repeatedly foisted upon an unawareAmerican public is generating a nationalcrisis of such proportions that our economycould be very adversely affected. The eco­nomic consequences are particularly apparent

in regard to the requirement by the Environ­mental Protection Agency that administratorsreport if asbestos js present in theirschools. What is the scmol administrator todo when he is required by law to post signs inhis school stating that asbestos is present?He has no option: he must have it removedbecause our cancer dogma translates the wordson his building sign to "a little childbreathing just one asbestos fiber may getmesothel ioma 30 years later." The schooladministrator, the teachers, the parents, arein a box. The only way out of the box is tocall for full ripout of the asbestos, eventhough well-informed experts know that manyasbestos-removal programs, perhaps most, willput more fiber into the air than if it wereleft in place. Building owners, schoolsystems, and local and state governments aresuing many businesses for costs and damagesrelated to asbestos removal, insurance com­panies are dropping liability coverage onworkers removing asbestos, and occupants ofbuildings are suing over health effects orpotential effects alleged to be caused byexposure to asbestos during renovation. Theasbestos-removal workers themselves, Ipredict, will soon be suing their contractorsbecause they too will believe that theirhealth is threatened by exposure to asbestos.

What are we to do about asbestos substi­tutes that may also be carcinogenic in man -­for example, the man-made mineral-fiber prod­ucts such as rock wool and fiberglass? sincethese products apparently cause excess lungcancer in long-term production workers, alogical and mnest cancer policy would requirethat they also be removed from schools. Willthe whole "asbestos-in-schools" scenario thenbe replayed, the main actor being fiberglassproducts rather than asbestos?

Fibers are not restricted to the schoolenvironment: many public and commercial build­ings, churches, and private homes containasbestos and the more modern fiberglass pro­ducts. Are we to go through the asbestos­removal program for these structures as well?Where is the money to come from to cover themultibillion-dollar costs? lbw do we insurethe workers? Is there any assurance at allthat the occupants of the buildings undergoingasbestos ripout will not receive more exposureto fibers than if the material were left inplace?

Lastly, what is to be done to controlmineral dusts perceived to be asbestos or

89

asbe~toslike: for example, the rock-formingamphIboles that occur in most hard-rock mines?Will all mine- and mill-wa.ste.I?ileSb~c~n~ider:ed toxic dumps? The challengetb themmmg mdustry is here and it is serious.

REFERENCES

Ames, B. N., 1983, Dietary carcinogens andanticarcinogens: SCience, v. 221, p. 1256­1264.

______~_, 1984, Letters: cancer and diet:Science, v. 224, p. 656-760.

Clifton, R. A., 1983, Asbestos: U.S. Bureauof Mines Yearbook, v. 1, Metals and Min­erals, p. 113-118.

Ibll, Richard, 1983, Prospects for the preven­tion of cancer: Clinical Radiology, v.34, p. 609-623.

Ibll, Richard, and Peto, Richard, 1981, Thecause of cancer - quanti tative est imatesof avoidable risks of cancer in the Unitedstates today: Journal of the Nationalcancer Institute, v. 66, p. 1193-1308.

Enterline, P. E., and Marsh, G. M., in press,Mortality of workers in the MMMF industry:V'brld Health organizational, InternationalAgency for Research on cancer Cbnference,Cbpenhagen, 1982, proceedings. [summaryreport published in World Health organiza­tion, EURO Reports and Studies 81, p. 84­85.]

Ross, Malcolm, 1981, The geologic occurrencesand health hazards of amphibole andserpentine asbestos, in Veblen, D. R.,ed., Reviews in mineralogy, v. 9A,Amphiboles and other hydrous pyriboles,mineralogy: Mineralogical Society ofAmerica, p. 279-323.

--"3"T-::--' 1984, A survey of asbestos-relateddisease in trades and mining occupationsand in factory and mining communities as ameans of predicting health risks of non­occupational exposure to fibrous minerals,in Levadie, B, ed., D3finitions for asbes­tos and other health-related silicates,ASTM STP 834: American Ebciety for 'Iestingand Materials, p. 51-104.

Saracci, R., and others, 1984, Mortality andincidence of cancer of workers in the man­made vitreous fibres producing industry ­an international investigation of 13European plants: British Journal ofIndustrial Medicine, v. 41, p. 425-436.

and

Canyon area of the Tertiary Cedar Hills andSeldon Hills volcanic-vent zone in south­central N9w Mexico. Fbster canyon tuffs con­tain up to 60 percent zeolite and average 40to 50 percent clinoptilolite.

'!he dominant mineral in the zeolite tuffsat the six deposits studied is generallymicrocrystalline and either chabazite orclinoptilolite. Lithic fragments, unalteredvolcanic glass, other zeolites, quartz,calcite, opal-CT, cristobalite, feldspar,evaporites, clays, and mafic minerals are also'constituents of the tuffs.

Zeolite minerals occur in rocks of diverselithology, age, and depositional environment.Zeoli tes are commonly the product of diage­netic reaction between volcanic glass andsaline, alkaline pore solutions. Severalgenetic models of authigenic zeolite formationhave been proposed (Hay, 1966, 1978; Sheppard,1971,1973; Munson and Sheppard, 1974).Deposi t characteristics differ due to varyingdepositional and diagenetic conditions duringzeolitization. We selected six zeolitic tuffdeposits in Arizona, N9w Mexico, and 'Iexas todescribe and compare their geologic, petro­logic, and mineralogic characteristics (Figure1). These deposits formed in either closed­hydrologic, open-hydrologic, or hydrothermalgroumwater systems.

'!he [ripping Spring Valley (DSV) chabazitein Arizona and the Buckhorn clinoptilolite inN9w Mexico formed in a late ceno:roic networkof northwest-southeast-trending, closed basinsextending from southeast Arizona into south-­west New Mexico (Scarborough and Peirce,1978). Air-fall tuffs at both deposits werezeolitized by reaction of vitric tuff withponded, saline, alkaline-lake waters. TheCasa Piedra, Texas clinoptilolite formedduring the Tertiary in a closed basin by zeo­lite metasomatism of volcanic glass. '!he air­fall tuffs of the Cuchillo Negro (Tertiary),New Mexico and Tilden (Eocene), Texasclinoptilolite deposits were zeolitically

90

Stephen L. PetersonZeotech Cbrporation3202 candelaria, NE

Albuquerque, NM 87107

Comparison of Selected Zeolite Depositsof Arizona! New Mexico! and Texas

Mark R. B::>wieand

James M. BarkerN9w Mexico Bureau of Mines am Mineral Resources

SOcorro, NM 87801

Air-fall tuffs have been altered to zeo­lite via reaction of volcanic glass with localpore solutions at the six localities discussedin this paper. These are in the southernBasin and Range Province of Arizona and NewMexico, and in the Trans-Pecos and CoastalPlain regions of Texas. Zeolitization occur­red in either closed-hydrologic, open-hydro­logic, or hydrothermal groumwater systems.

'!he [ripping Spring Valley (DSV) chabazitein Arizona and the Buckhorn clinoptilolite inN9w Mexico originated in a late cenozoic net­work of closed-hydrologic, lacustrine basinsextending from southeast Arizona into south-­west New Mexico. At DSV, two potentiallycommercial chabazite-rich tuffs are inter­bedded with lacustine mudstone. The mainzeolite tuff contains up to 90 percentchabazite. The upper zeolite tuff averagesapproximately 67 precent chabazi teo At theBuckhorn deposit, two clinoptilolite-richtuffs are interbedded with lacustrine mLdstonein the upper part of the Gila Conglomerate.'!he lower zeolite tuff contains up to 90 per­cent clinoptilolite. The upper zeolite tuffcontains over 60 percent clinoptilolite.

The Casa piedra clinoptilolite is in theTrans-Pecos region of Texas. It formed duringthe Tertiary in a closed basin containing aplaya lake. The Casa Piedra tuff averagesabout 60 percent clinoptilolite.

Air-fall tuffs of the Cuchillo N9gro, N9wMexico am Tilden, Texas clinoptilolite depos­its were zeolitically altered by either perco­lating ground waters in open-hydrologic sys­tems or locally by ponded, saline, alkalinesolutions. Cuchillo Negro tuffs are Tertiaryand average approximately 50 percentclinoptilolite. Clinoptilolite-rich tuffs ofEbcene age have been mined from four quarriesat the Tilden deposits. Tuffs from theKuykendall and Buck Martin quarries containapproximately 50 to 60 percent clinoptilolite.

low temperature, Si02 - rich, hydrothermalsolutions altered air-fall tuff toclinoptilolite and chabazite in the Foster

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Figure 1. Location of the six zeolite deposits discussed in this study. The deposits are keyedto their mode of zeolite authigenesis and parent-ash composition.

altered in open-hydrologic systems. Hydro­thermal solutions altered air-fall tuff toclinoptilolite and chabazite in the FosterCanyon area of the Cedar Hills and SeldenHills volcanic-vent zone (Tertiary) in south­central l"Bw Mexico.

The DSV deposit (Az. Dept. of Min. Res.,1978; Krieger, 1979; Eyde, 1982; Sheppard andGude, 1982; Bowie, 1985) and the Buckhorndeposits (Olander, 1979; Eyde, 1982; Sheppardand Gude, 1982; Sheppard and Mumpton, 1984;Bowie, 1985) have been extensively studied.Walton and ~oat (1972) briefly described theCasa Piedra and Tilden deposits of Texas.This paper is the first published accountfocusing on zeolitic tuff at Cuchillo Negroand Fbster canyon, New Mexico.

THE CHABAZ ITE DE:J?(EIT N£DRIPPING SPRING VAllEY" ARIZasIA

'!he Dripping Spring Valley (ffiV) chabazitedeposit, about 23 miles south of Globe, GilaCbunty, Arizona, is one of several late ceno­zoic zeolite deposits formed in closed-hydro­logic, shallow-lake basins in southeastArizona and southwest New Mexico (Feth, 1964).It is a narrow, north-northwest-trendingintermontane valley bounded by the pinal (N),Mescal (NE), and Dripping Spring Mountains(SW) •

91

Ten air-fall tuffs are known to be inter­bedded with more than 2,200 feet of Tertiaryand Quaternary epiclastic fluviolacustrinedeposits. Banks and Krieger (1977) tentative­ly correlate these deposits with the Big DomeFormation (early Miocene) in the Gila RiverValley and the Q.1iburis Fbrmation (Miocene orPliocene) of the San Pedro Valley. At leastfive of the 10 tuffs were zeoliticallyaltered, predominantly to chabazite. Theal tered tuffs also contain trace to abundantunaltered volcanic glass, quartz, calcite,dolomite, feldspar, evaporite minerals, maficminerals, and clay minerals that are eitherdetrital or authigenic.

'!he Anaconda Minerals Cbmpany acquired thedeposit in 1978. Anaconda drilled over 150exploration holes targeting two zeolite tuffs,the main and upper horizons. They abandonedtheir claims in september, 1983.

The main zeolite tuff is stratigraphicallythe lowest tuff exposed (Figures 2 and 3). Itunderlies at least 1 square mile of basin-filland ranges from 0.25 to 1.74 feet thick. Themain zeolite tuff consists of three distinctlithologies: 1) a lower zeolitically alteredash, 0.15 to 0.87 feet thick, with about 10percent detritus, 2) a middle zeoliticallyaltered ash, 0.14 to 0.20 feet thick, which islaminated and thin-bedded, with traces ofdetritus, clay, and calcite, and 3) the

three ashes may have accumulated between sepa­rate ash-fall events. More likely, thelaminae accumulated continuously and werepunctuated by initial ash sedimentation andlater reworking of the same ash. The lowerash bed of the zeoli te horizon may representash initially deposited in the lake. Themiddle and upper ash beds probably are thesame tuff originally deposited around the lakeand later washed or blown into it. The mainzeolite horizon contains infrequent sedimen­tary structures. These include ripple markson laminae surfaces, soft-sediment deforma­tion, and calcified root impressions. Thesedimentary structures indicate partialreworking and disturbance of the lake bottomby currents and bioturbation.

zeolitic alteration of the main zeolitetuff is heterogeneous. Sampling in 1960 indi­cates that the main tuff grades from clean,unaltered ash at the north end of the depositto 90 percent chabazite at the south end(Eyde, 1982). x-ray diffraction (XRD) analy­sis of powder-press mounts of tuff by Anacondareturned from 0 to 69 percent chabazite(Bowie, 1985). The inverse relationship be­tween the amount of chabazite and the amountof unaltered volcanic glass in the tuff sug­gests that the glass is altered to zeolite.Chabazite content generally increases basin­ward, where more saline, alkaline conditionswere conducive to more complete zeolitizationof the tuff. The unaltered glass contentincreases towards the lake margins. Fresh­water influx is greater here so there is lesszeolitization owing to lower pH and salinity.

SCanning electron microscopy (SEM) of themain zeolite tuff reveals chabazite andsmectite + mixed-layer illite/smectite pseudo­morphic after volcanic glass (Figure 4).

Figure 4. SCanning electron micrograph of themassive bed of the main zeolite tuff from theAnaconda prospect pit. Leafy smectite andsubhedral to euhedral chabazite cubes orrhombs form stacked, radial stringers up to 10microns long on the volcanic glass substrate.Chabazite crystals appear also to have grownon smectite.

92

stratigraphically highest and most massivebed, 0.30 to 0.67 feet thick, consisting ofash altered to zeolite (Eyde, 1982).

The main zeolite horizon was deposited ongently sloping alluvial-fan and playa-lakesurfaces. Clay laminae de:fDsi ted between the

Source: Bowie. 1985.

Figure 3. View lookiITJ northwest at .the mainand upper zeolite tuffs interbedded with la­custrine claystone in the Dripping springValley deposit. Hammer rests on the white,conchoidally fractured main' zeolite tuff. Aledge of grayish-white upper zeolite tuff capsthe hill. Blocks of upper zeolite tuff haveslid down the hillside.

Source: Bowie. 1985.

Figure 2. SOuthwest view of a prospect pit atthe DrippiITJ Spring Valley chabazite deposit.The white zeolite ore piled on the pit flooraloITJ the south side is from the main zeolitetuff (MT). A red lacustrine claystone (eS) isexposed at the base of the pit wall. It isoverlain by the blocky, ledge-forming upperzeolite tuff (UT). A 1-foot-thick layer ofwhite, reworked zeolitic sandy claystone (RW)is interbedded with lacustrine claystone about1.5 feet above the upper zeolite tuff.

'!HE CLINOP'l'IIDLITE DEPunTlIT BOCKHORN, NEW MEXIa>

The Buckhorn clinoptilolite deposit is inthe Mangas Trench, a northwest-southeast­trending structural low, bounded by normalfaults on the east and west. Clinoptilolitehas been mined at Buckhorn from one of twozeoli tic air-fall tuffs. These tuffs areeXIDsed on the west side of DJck Green Valleyin secs. 3, 4, and 10, '1'. 15 S., R. 18 W.,

northwest end of the Bowie depositional basinwas a calcium-rich, low-salinity environmentcharacterized by calcite concretions within ahigh-grade zeolitic tuff. The deeper, south­east end of the l:bwie basin was a sodium-rich,high-salinity environment characterized by theoccurrence of high-sodium chabazite andthenardite within the same high-grooe zeolitictuff (Eyde, 1982). In contrast, at DSV, nosuch lateral gradation of cao: Na20 ratios isapparent from chemical analyses of the tuffs.Significant variation in lake water salinityis not apparent between the shallow, northwestend of the rsv basin and the deeper, southeastend. This relationship suggests that thedeeper end at DSV was less saline than thedeeper portion at the Bowie deposit. Lowersalinity precluded formation of analcine atIBV; higher salinity favored it at l:bwie.

SEM of DSV zeolitic tuffs reveals theparagenetic sequence of authigenic mineraliza­tion to be: unaltered volcanic glass --->smectite+ mixed-layer illite/smectite, alloverlapped by chabazite. Rare late-stageclinoptilolite and erionite probably crystal­lized at the expense of the earlier-formedsmectite and chabazite. The complete basin­ward paragenetic sequence of una1tered vol­canic glass ---> alkalic, silicic zeolites --­> analcine ---> potassium feldspar observedin many closed-hydrologic zeolite deposits(Sheppard and Gude, 1968; Hay, 1977; Surdam,1977) probably did not develop in the DSVtuffs (l:bwie, 1985). This partial developmentof the full paragenetic sequence is due tobasinwide relatively low salinity and pH whichallowed progression along the sequence only toclinoptilolite and erionite.

The DSV tuffs were altered mostly tochabazite. Chabazite precipitated when thehydrogen to alkali ion activity ratio de­creased below the level for smectite crystal­lization. This precipitation followed dis­solution of the rhyolitic volcanic glass inthe tuffs by moderately saline and alkalinepore solutions shortly after deposition.Chabazite authigenesis was favored by therelatively silica-poor environment in whichthe activity of H20 was high and the K to Na +Ca+ Mg activity ratio was low (Bowie, 1985).Zeolitization of the fresh rhyolitic volcanicglass in the tuffs produces enrichment of Caand Mg and loss of K20 am Si02•

93

Chabazite occurs as subhedral to euhedralcubes or rhombs varying from much less than 1micron up to 2 microns on a side. The crys­tals are commonly intergrown forming ei therclusters or radial, fan-like stringers up toabout 10 microns long. Smectite and mixed­layer illite/smectite occur as pore-fillingand pore-lining, leaf-like, interconnectedridges much less than 1 micron wide and up toabout 5 microns long. Chabazite is locallypseudomorphic after smectite (Figure 4).

The upper zeolite tuff averages approx­imately 67 percent chabazite. It is about 5feet stratigraphically above the main zeolitetuff (Figures 2 and 3). The upper zeolitetuff averages about 1.5 feet thick, ranges upto 5.5 feet thick, and underlies over 3 squaremiles of basin-fill (Bowie, 1985). Threedistinct lithologies with highly variablethickness and lateral continuity form theupper zeolite tuff: 1) a lower thin-bedded toplaty bed, 2) an overlying massive bed, and 3)an upper thin-bedded to platy bed.

Seven silicic air-fill tuffs, the lowestof which lies about 150 feet stratigraphicallyabove the upper zeolite tuff, underlie about 4square miles of basin-fill at the north end ofrsv (l:bwie, 1985). The seven tuffs are inter­bedded with lacustrine millstone, crop out overa vertical distance of about 60 feet, andaverage about 1.5 feet thick. The lower twoare locally altered to chabazite. A"rhyolitic" tuff (Cbrnwall and Krieger, 1978)approximately 3 feet thick is stratigraph­ically the highest tuff exposed in DSV. Ithas been partly reworked and waterlain and islocally altered to chabazite.

Fluvial and lacustrine samples from DSVconsist of discrete illite, mixed-layerilli te/smectite, chlorite, smectite (mainlysodium montmorillonite), and kaolinite indecreasing order of abundance (Bowie, 1985).These relationships were determined by XRDfrom the <2 microns size fraction. The clayminerals are predominantly detrital. Someillite, smectite, and mixed-layerillite/smectite formed authigenically viareaction of precursor volcanic glass or clayminerals with the saline, alkaline water inthe lake.

The air-fall tuffs of DSVare rhyolitic(Cornwall and Krieger, 1978; Krieger, 1979).X-ray florescence (XRF) spectrometry of DSVbulk zeolitie-tuff and unaltered tuff samplesindicates that zeolitization of freshrhyolitic ash produces an enrichment in Al203,MgO, CaO, and H

20, and a loss of si02 and K20(Krieger, 1979; Bowie, 1985). In some tuffs,Na20 is enriched but it is depleted in others.Edson (1977) and Eyde (1982) report, for theBowie chabazite deposit, a lateral chemicalgradation of increasing CaO:Na20 ratios inzeolitic tuff. They correlate this with in­creasing lake water salinity. The shallow,

Figure 6. Scanning electron micrograph fromthe lower horizon of the Buckhorn deposit.The paragenetic relationships between thevolcanic glass, smectite, and clinoptiloliteare clearly shown. Wispy smectite sparinglycoats the volcanic glass grain. Cl uste'rscoffin-shaped clinoptilolite lathsfrom the glass into a cavity.

A lower layer in this tuff is 0.5 feet thickand contains about 48 percent clinoptiloliteand about 48 percent chabazite (Eyde, 1982).The lower tuff also contains a clinoptilolite­heulandite intermediate phase, heulandite,analcine, magadiite chert, quartz, calcite,illite/smectite, plagioclase, flourite, horn­blende, and biotite (Olander, 1979; Eyde,1982; Sheppard and Mumpton, 1984). The upperzeolite tuff is massive, yellowish- tograyish-whi te, and is 1 feet thick. It con­tains over 60 percent clinoptilolite and atrace of erionite.

Lower tuff SEM reveals clinoptilolitepseudomorphic after volcanic glass andsmectite (Figure 6). Clinoptilolite occurs asbushy clusters of coffin-shaped laths commonlyradiating into voids. The crystals rarelyexceed 3 microns in length and 2 microns inwidth. Smectite coats the volcanic glassshards and appears as wispy, interconnectedridges forming a honeycomb texture.

Interstitial solutions passing throughBuckhorn tuffs were saline and alKaline.solution composition probably approachedof Lake Magadi, a NaHC03-C03 brine (Eugster1970), based on the occurrence of "'c":lc"..... ~,.~

chert at Buckhorn. The solutions atwere hypersaline and probably werebasinward (Olander, 1979) during zeoltion. The chert precipitation suggeststhe brine was unsuitable forwi th low si to Al ratios, such as L:1JlClL'a~OJ.

Botassium feldspar formation was inhibitedthe low. K to Na + Ca + Mg activity

94

Figure 5. At the Buckhorn clinoptilolitedeposit, a resistant 4-foot-thick section ofthe lower zeolite tuff has influenced theformation of a 20 foot knickpoint in anephemeral-stream arroyo.

about 1 mile south of Buckhorn, Grant Cbunty,~w Mexico. '!he exploited tuff is visible tothe west from U.S. Highway 180. SOme poten­tially zeoli tized tuffs crop out in the cen­tral and eastern portions of Duck GreenValley.

The zeolitized air-fall tuffs of theBuckhorn deposit are interbedded with thePliocene-Pleistocene Cactus Flat beds of theupper part of the Gila Cbnglomerate (Heindl,1958). Olander (1979) recognized four dis­tinct depositional environments in the depos­its: 1) soil which possibly developed alongthe edge of an alluvial fan, 2) intermittentstream-channel and adjacent overbank deposits,3) interchannel, flood-plain deposits, 4)lacustrine or ponded deposits. The deposit iscorrelative with diatomite deposits, about 3miles north of Buckhorn, that were placed atthe boundary between early and middle Plio­cene, an approximate age of 3 m.y. (Olander,1979; Eyde, 1982). The U.S. Bureau of Minesexplored, sampled, and tested the diatomite inthe early 1940's. The results of the testingare unpublished but informal reports indicatethe diatomite to be of good quality and atleast 25 feet thick (Gillerman, 1964).

The two clinoptilolite-rich tuffs at theBuckhorn deposit are traceable for approx­imately 1 mile along strike. The tuffs areseparated by about 20 feet of green and brownmudstone containing abundant smecti te, zeo­lites, quartz, and calcite, and minor to traceillite, plagioclase, and secondary gypsum(Sheppard and Mumpton, 1984). Both zeolitictuffs were probably originally rhyodaciticwith a source in the Iatil-Mogollon volcanicfield (Olander, 1979).

The yellowish-white, massive, lower zeo­lite tuff is 3 to 5 feet thick and contains upto 70 to 90 percent clinoptilolite (Figure 5).

Winton 3.01111Chlorld.2.8ml

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units vary in form, thickness, lithology, andstratigraphic relationships. The volcanicrocks contain five depositional sequences(Jahns and others, 1978): early to middleTertiary 1) upper andesite sequence, 2)rhyolite-trachyte sequence, 3) lower andesitesequence, 4) dacite-rhyodacite sequence, andearly Tertiary 5) latite-andesite sequence.These five depositional sequences togethercontain many members, at least 12 of which arewater-laid tuff. The water-laid tuffs mayhave been in part zeolitically altered bysaline and alkaline pore water. Propylitical­ly altered andesite (unit Tabt of Maxwell andHeyl, 1976) crops out throughout much of thecentral portion of the Winston quadrangle.Tabt contains a discontinuous, thick, green,fine- and coarse-grained, water-laid tuff nearthe top. This tuff may be altered in part toclinoptilolite •

8.··.. ·· ..·..• ·. Tertiary cllnoptllollte./ tuff and conglomerllle,

ahowlng contachl

1_- Ephemeral Ilream

Figure 7. Tertiary cl inoptilol ite tuff andconglomerate at the Cuchillo Negro deposit.Starred sampl e local it ies contain cl ino­ptilolite confirmed by XRD (modified fromMaxwell and Heyl, 1976).

95

'DIE CI.lHJPTIIDLTI'E :DEPCEITM COCHILW NEGRO, Nm MEXIa>

Tuff alteration initially formed minorsmectite with overlapping heulandite-groupmineralization, including clinoptilolite.Erionite and analcine precipitated laterthrough reactions involving localized, highlysaline, alkaline sOlutions. The two laterzeolites locally replaced the earlier high­silicon zeolites.

lnuorite in a zeolitic tuff occurs about2.5 miles east of Buckhorn. The fluorite isvery small « 1 micron) and makes up 20 to 3 0percent of the tuff. It occurs as pellets andooids embedded in a matrix consisting predomi­nantly of micrometer-size mordenite andsmecti te (Sheppard and Mumpton, 1984). Thepellets and ooids probably are products ofprimary precipitation of fluorite andmagadiite. '!hey formed where dilute, calcium­bearing water from springs or streams mixedwith fluorine-rich, saline, alkaline-lakewater. The pellets are possibly biogenic andoften form the cores of ooids. Both pelletsand ooids were transported and reworked intothe tuff prior to zeolitization (Sheppard andMumpton, 1984).

'!he CUchillo N3gro clinoptilolite depositis part of a thick, nonmarine Cenozoic sedi­mentary and volcanic section. This sectionoccupies the southern end of the WinstonGraben between the Black Range to the west andthe Sierra CUchillo to the east. '!he depositis about 4 miles south of Winston, SierraCbunty, N3w Mexioo.

Access to the deposi t is via N.M. Highway52 (paved), which intersects I-25 just northof Truth or Consequences. Follow Highway 52northwest to Winston, then follow Cbunty lbad6 and USFS 157 (both improved dirt) southalong the Chloride Creek drainage for approx­imately 4 miles. The central area of thedeposit is at the junction of USFS 157 and theSt. Cloud Mining Cbmpany's mill road. '!he st.Cloud Mill is 2 miles northwest of this inter­sec t ion (Figure 7).

A Tertiary clinoptiloli te tuff andconglomerate unit occurs within the Winston 71/2-minute quadrangle (Maxwell and Heyl,1976). This unit is in sees. 34 and 35, T. 11S., R. 8 W., and sees. 2, 3, 10, 11, 14, 15,21, and 22, T. 12 S., R. 8 W. It is exposedfor approximately 5 miles along a north-southtrend (Figures 7 and 8) and crops out west andnorth of the confluence of S:mth Ebrk Arroyo,Chloride Creek, and CUchillo N3gro Creek. '!heuni t is displaced by several north-northwest­trending normal faults, and dips up to 60degrees to the west-southwest.

'!he clinoptilolitic tuff and conglomerateis interbedded in a complex 'Il3rtiary volcanicand sedimentary section that is at least 2,500feet thick in the Sierra CUchillo. Individual

Figure 8. Exposure of approximately 60 feetof faulted, steeply dipping, clinoptilolitictuff along South Fork Arroyo at the CuchilloNegro zeolite deposit. Telephone poles atbase of the hill at far left and right centerprovide scale.

The Tertiary volcanic rocks are unconfonn­ably underlain by the Lower Permian Abo andBursum Fbnnations, and the Upper PennsylvanianMadera Limestone. The volcanic section isoverlain by a thick sequence of Tertiary andQuaternary fine- and coarse-grained basinfill. The basin fill represents erosion ofolder rock uni ts exposed in the nearby high­lands. Jahns (1955) refers to the strataoverlying the volcanics as the "Winston beds"and notes that they can be traced southwardinto the type section of "Palomas gravel".The sediments have also been divided into the"Rio Grande gravel", Gila Conglomerate, andSanta Fe Formation, but definitive correla­tions with other areas and sections have notyet been confirmed (Jahns and others, 1978).Jahns collected early Pleistocene vertebratesand fresh-water mollusks from the upper partof the Winston beds.

The clinoptilolitic sequence containsnumerous zeolitically altered, light-buff tochalk-white tuffs interbedded with silty tosandy altered-tuff, sandstone, and conglomer­ate. Limited XRD analysis of powder-pressmounts of this unit returned an average ofapproximately 50 percent clinoptilolite(Figure 7). varying amounts of unalteredvolcanic glass, quartz, calcite, feldspar,cristobalite, smectite, kaolinite, illite, andmixed-layer clay minerals also occur. Tracesof chabazite, dolomite, pyrite, magnetite,biotite, and manganese minerals are present.

The paragenetic sequence of authigenicmineralization, based on SEM, is unalteredvolcanic glass ---) early smectite ---)cristobalite(?) ---) clinoptilolite ---) latesmecti te (Figure 9). Smectite is pseu:1omor­phic after the glass and occurs as leafy,interconnected ridges forming a honeycomb

texture. Clinoptilolite formed from bothvolcanic glass and smectite. It occurs assubhedral to euhedral, coffin-shaped, mono­clinic laths, either isolated or in clusters(Figure 9). The laths are up to 5 micronslong and wide and up to 1 micron thick.Second generation smectite locall}' coatsclinoptilolite •

Figure 9. Scanning electron micrograph ofclinoptilolitic tuff from the Cuchillo Negrozeolite deposit. Honeycomb smectite andcoffin-shaped clinoptilolite laths have grownon a volcanic glass shard. Cl inoptilolitehas also displacively overgrown smectite.

The tuffs in the Cuchillo Negro depositwere apparently zeolitically altered bygroundwater in an open-hydrologic system.The groundwater chemistry was modified byhydrolysis and dissolution of the vitric tuff.The zeolitization cuts across stratigraphicboundaries, a characteristic of alteration inopen-hydrologic systems. fbwever, local zeo­litization by ponded, saline, alkaline solu­tions cannot be ruled out.

'lHE CLINOPrIIDLITE DEIUHTAT FOO'lER CANYOO, NEW MEXIOO

The Foster Canyon clinoptilolite depositlies primarily in the easternmost half of T.21 S., R. 2 W., and in the westernmost sec­tions of T. 21 S., R. 1 W. It is about 16miles northwest of Las Cruces, and is nearRadi um springs, D.:ma Ana County, New Mexico.Several zeolitically altered air-fall tuffsare exposed in the Fbster canyon collapse areaof the Tertiary Cedar Hills and selden HillSvolcanic-vent zone (seager and Clemons, 1975).

The deposit can be reached by taking Exit19 (Interstate 25), proceeding west to U.S.Highway 85, and turning right (north). Con­tinue through Radium springs and turn left(west) onto the upper dirt road just south of

96

I1

mile marker 17. Drive 3.3 miles west thenturn right (north) off the ridge onto a jeeptrail and proceed 2.6 miles until reaching theLeonard Minerals Cbmpany prospect pit, locatedin the SEI/4 SWI/4 NWI/4 sec. 14, T. 21 S., R.2 W. The deposit is in the Cbrralitos Ranch 71/2-minute quadrangle mapped by Clemons(1976) .

In the Cedar Hills and Selden Hills ventzone, the Tertiary section includes the EbcenePalm Park Formation, the Oligocene Bell 'IbpFormation, and the Miocene to Pliocene(?)Rincon Valley Formation (Seager and others,1971; Seager and Clemons, 1975). The palmPark Fbrmation consists of about 2,000 feet ofepiclastic, laharic, andesitic detritus.other facies present in the Palm Park includefluvial, basin-floor, and piedmont-slope(toe), and subvolcanic sills, dikes, and minorflows (Seager and Clemons, 1975). The PalmPark Formation is unconformably overlain bythe Bell TOp Formation. The Bell TOp in thevent zone can be subdivided into four units:1) lower tuffs and breccia, 2) ash-flow tuff,3) upper air-fall and epiclastic deposits, and4) flowbanded rhyolite domes and flows (seagerand Clemons, 1975). Ibrous to dense crystal­vitric ash-flow tuff and muddy to sandy con­glomerate interfinger with tuffaceous sedimen­tary members.

In Foster Canyon, up to 800 feet of whiteto tan, rhyolitic air-fall tuff, breccia, andinterbedded epiclastic pebbly sandstone weredeposited as moat-fill after vent-clearing,explosive eruptions (Figure 10). Clemons(1976) refers to these deposits as the uppertuffaceous sedimentary member. The lowerparts of the member contain clasts of Paleo­zoic limestone, Palm Park Fbrmation, ash-flowtuff, and vesicular andesite. Ash, cross-

Figure 10. Bedded, reworked air-fall tuff inthe Cedar Hills and Selden Hills vent zoneexposed at the Foster Canyon clinoptilolitedeposit. It contains approximately 50 percentclinoptilolite with subordinate lithic frag­ments, unaltered volcanic glass, smectite, andfeldspar. Hammer is for scale.

97

(Seager andeither formedmember or formed

'!he Tertiaryis separated from thethe overlying Rinconangular unconformity. An angularalso separates the Rincon Valleyfrom the overlying piedmont-slope facies ofthe Pleistocene Camp Rice Formation. LatePleistocene to fblocene arroyo, fan, and theterrace, as well as minor playa deposits andeolian sand, unconformably overlie the CampRice.

The dominant structural feature of theFbster canyon deposit is the north-northeast­trending, late Tertiary Cedar Hills normalfault. This and subsidiary late Tertiaryhigh-angle normal faults are superimposedacross the GbOdsight-Cedar Hills depression, abroad, shallow, volcano-tectonic sag of Oligo­cene age (Seager, 1973). uplift and erosionalong these faults exposed the volcanic-fillof the depression, as well as the strata andstructure of the Cedar Hills vent zone alongthe eastern margin of the depression (Seagerand Clemons, 1975). These volcano-tectonicfeatures are precursors to the Rio Granderifting (seager and Clemons, 1975).

'!he upper tuffaceous sedimentary member isextensively zeolitized and locally opalized.several siliceous or fused-tuff structures areconspicuous at the surface as resistant,sinuous, crosscutting ridges with up to 3 feetof relief above the surrounding surface. '!hefused-tuffs are cemented by opal-CT, sug­gesting a relatively low-temperature «65degrees C) alteration event (McGrath, 1985).The tuffs were probably silicified as siO ­rich hydrothermal solutions moved up alongfractures. They are now prominent owing todifferential erosion.

McGrath (1985) collected samples at I-footintervals for 20 feet along a traverse ofthree fused-tuff ridges in the upper tuffa­ceous sedimentary member. In addition toopal-CT, XRD analysis detected smectite andclinoptilolite. The relative abundances ofsmectite and clinoptilolite are inverselyproportional to their distance from the fused­tuff ridges. Clinoptilolite is more concen­trated at the ridges and smectite is moreooncentrated away from them. This relation­ship supports a hydrothermal origin for atleast some of the zeol i te. Other zeol i te maybe post hydrothermal. The clinoptilolite isunstable in the modern soil (McGrath, 1985).

Clinoptilolite was detected in secs. 14and 25, T. 21 S., R. 2 W., and along theboundary of secs. 19 and 30, T. 21 S., R. 1 W.Chabazite was found to be the dominant zeolitein several samples from the west-central partof sec. 14, T. 21 S., R. 2 W., but is gener-

ally much less abundant then clinoptiloli teoAnalcime occurs rarely in the west-centralpart of section 14 (McGrath, 1985). ZeotechCorporation analyzed several samples by XRDfrom sec. 2, T. 20 S., R. 2 W., secs. 11, 13,14, and 25, T. 21 S., R. 2 W., and sec. 19, T.21 S., R. 1 W.; all are nonzeolitic.

Zeotech Corporation augered over 300 holesinto the Foster Canyon deposit and analyzedtuffaceous samples by XRD. The tuffs containup to 60 percent zeolite, am average 40 to 50percent clinoptilolite. Reserves are tenta­tively estimated at 200,000 to 300,000 shorttons of 50 percent clinoptilolite. Exactreserve calculations are difficult to makebecause of the irregular gradation betweenzeolitized and nonzeolitized tuff and theintermixing of siliceous, fused-tuff zoneswith zeolitic tuff.

In addition to zeolites, opal-CT andsmectite, the tuffs contain lithic fragmentsranging in composition from basalt torhyolite, varying amounts of unaltered vol­canic glass, and minor quartz, calcite,biotite, kaolinite, sanidine, K-feldspar, andalbite. The zeolitic tuff is generally mas­sive and structureless. Local cross-beddingis present probably due to the tuffs havingbeen reworked by fluvial processes (Figure10) •

The paragenetic sequence of authigenicmineralization, determined with SEM and inthin section, is unaltered volcanic glass --->early smectite --> clinoptilolite, opal-cr --­> late smectite (Figure 11). Honeycombsmectite coats glass and clinoptilolite.Opal-CT occurs as clusters or stringers ofsubrounded balls up to 5 microns in diameter.The paragenetic relationship between opal-CT

Figure 11. Scanning electron micrograph ofzeolitic tuff at the Foster Canyon clinoptilcrlite deposit. Chaotic and commonly inter­grown, coffin-shaped clinoptilolite laths areintermixed with clusters or stringers of sub­rounded balls of opal-CT.

98

-------------------"--~-

and clinoptilolite is unclear, but they ap­parently coexist. Clinoptilolite occurs assubhedral to euhedral, coffin-shaped lathsthat are commonly intergrown and chaoticallyarranged. The laths are abou arranged. Thelaths are about 20 to 30 microns long, up to10 microns wide, and up to 5 microns thick.

mE CLIlO?'.ITWLI'I'E DEPOOITM CASA PIEDRA, "mXAS

'!he casa piedra clinoptilolite deposit isin Presidio Co., 'Iexas, about 1 mile northeastof Casa Piedra and about 40 miles south ofMarfa. A clinoptilolite-rich tuff crops outin the lower part of the Tertiary TascotalFormation. The Tascotal crops out almostcontinuously from approximately 6 miles southof Marfa to nearly the Rio Grande south of theBofecillos Mountains. North of Casa Piedra,the Tascotal crops out in low hills andcuestas. Clinoptilolite is a minor constit­uent in the matrix of high-energy fluvialsandstones along this outcrop line but islocally concentrated in an air-fall tuffinterbedded with . low-energy lacustrine rocks.Walton and Groat (1972) collected nearly pureclinoptilolite samples just north and north­east of casa piedra.

'!he casa piedra deposit contains a white,air-fall tuff 1 to 5 feet thick am averagingabout 60 percent clinoptilolite (Figure 12).

Figure 12. Clinoptilolite-rich tuff overlyinglacustrine mudstone in the Tertiary TascotalFormation at the Casa Piedra zeolite deposit.This tuff is 1 to 5 feet thick and containsapproximately 60 percent clinoptilolite andminor unaltered volcanic glass, cristobalite,feldspar, and biotite.

The tuff also contains unaltered volcanicglass, and minor biotite, smectite, feldspar,and cristobalite. '!he paragenetic sequence ofauthigenic mineralization, based on SEM, isunal tered volcanic glass---> early smectite---> clinoptilolite ---> late smectite (Figure13) • Fuzzy, honeycomb smectite has grown from

8 miles west, the Dilworth quarry about 8miles southwest, and the Henry Martin quarryabout 1 mile southeast of Tilden. '!he depos­its occur in the Eocene Manning Fbrmation ofthe Jackson Group within Gulf Coast strati­graphy. "The Jackson Group is an extensiveseries of strike-oriented sand units whichcomprise the south Texas strandplain-barrierbar system. '!he sands grade updip and downdipinto predominantly mud systems, the southTexas lagoonal-coastal plain and the shelfsystems, respectively" (Walton and Groat,1972) •

The zeolitized air-fall tuffs wereoriginally deposited in quiet lagoons behindbarrier islands, and/or in associated coastal­fluvial and washover- fan environments (Waltonand Groat, 1972).

The zeolitized air-fall tuffs wereoriginally deposited in quiet lagoons behindbarrier islands, and/or in associated coastalfluvial and washover fan enviromnents (Waltonand Groat, 1972). The source of the tuff mayhave been northern Mexico (B. Ibnegan, pers.comm., 1984). zeolitization probably occurredin open-hydrologic systems where meteoricwaters reacted with vitric tuff. Local alter­ation in ponded saline, alkaline waters(closed-hydrologic) is also possible.

The clinoptilolite-rich tuffs are white,gray, or various pastel shades and are moreresistant to erosion than adjacent beds. '!heyform massive, blocky, or flaggy ledges wi thsubconchoidal to conchoidal fracture. Theyare up to 3 feet thick (Walton and Groat,1972) and each ledge consists of individualbeds ranging in thickness from 1 to 3 inches.ledges are laterally persistent except whereerosion, dominantly in paleo-channels, hasremoved the tuffs. SOme tuffs are structure­less, some are laminated, and some displaysmall-scale foreset or trough crossbeds.Climbing ripples characterize some highlyzeolitized units (Walton and Groat, 1972).XRD analyses indicate that in addition toabundant clinoptilolite, the tuffs containvarying amounts of unaltered volcanic glass,montmorillonite, opal-CT, sodic plagioclase,and quartz (Walton and Gr'oat, 1972).

Kuykendall pits

'!he three Kuykendall pits trend northeast­southwest over approximately 10 acres. Theycontain clinoptilolite-rich tuffs 6 to 12 feetthick (Figure 14). "The tuffs are thickest inthe center of the trend, grade laterally intomuddy, tuffaceous units to the west, and dis­appear into the subsurface to the north andeast" (Walton am Gr'oat, 1972).

The Kuykendall tuffs overlie a buff toblue-green, well indurated, silicified sand­stone with local clay-size detrital matrix orclay interbeds. A light-gray to reddish­brown, locally tuffaceous clay with silty and

99

'lHE CLINOPTIIDLITE DEPa3ITSAT TILDEN, '.lEXAS

Figure 13. Scanning electron micrograph ofclinoptilolite-rich tuff from the Casa Piedrazeolite deposit. The etched volcanic glassshard (right center) is coated with honeycombsmectite. Patches of coffin-shaped clino­ptilolite laths have grown from the smectiteand volcanic glass.

The Tilden clinoptilolite deposits arenear the town of Tilden, McMullen County,Texas; approximately 80 miles south of SanAntonio and 100 miles northwest of CorpusChristi. Tb date, clinoptilolite is the onlypotentially commercial zeolite found in southTexas. Clinoptilolite-bearing tuffs have beenmined from four quarries, named after theproperty owners: 1) Kuykendall, 2) BuckMartin, 3) Henry Martin, and 4) Dilworth. '!heKuykendall and Buck Martin quarries are about

an etched volcanic-glass substance and locallycoats clinoptilolite. Clinoptilolite crystal­lized from a volcanic-glass precursor and fromsmectite. It occurs as isolated laths or asclusters of subhedral to euhedral, coffin­shaped laths often lining vugs and radiatinginto voids. The clinoptilolite laths are upto 7 microns long, 5 microns wide, am up to 3microns thick.

The tuff was altered to zeolite by reac­tion of volcanic glass with saline, alkaline­pore solutions in a closed-hydrologic system,probably a playa lake and peripheral environ­ment. '!he tuff overlies brown, sandy mldstoneand has worm and clam burrows at the base. Itcrops out in circular fashiop over approx­imately 1 square mile. '!he deposit also con­tains tuffaceous sandstones laid down in high­energy fluvial systems. The central portionof the deposit was largely eroded prior topaleochannel formation. Reserves are about100,000 short tons of material averaging 60percent clinoptilolite.

Figure 14. Drill rig at the end of one of thethree Kuykendall pits near Tilden, Texas.Note the blocky nature of the zeolite ore.The McMullen Co. Highway Dept. hauled rockfrom this and other nearby zeolite quarriesfor road-fill. The streets of Tilden andmany county roads are constructed from thismaterial. The zeolite ore compacts well, doesnot get slippery when wet, and is hard enoughto resist breakdown under heavy traffic.

sandy interbeds, overlies the tuffs. uncon­solidated sand and gravel locally overlie ortruncate this sequence. A black to reddish­brown soil, generally less than 3 feet thick,caps the whole sequence. A unifonnly thick (4feet) lignite bed underlies the sedimentarysequence and is an excellent basal markerhorizon throughout the deposit.

Tuffs at Kuykendall are white, gray, orpale yellow above the groundwater table (GWT)and are reduced and bluish-gray below it. '!hetuffs are locally very hard and, in places,are clayey, silty, and sandy. Climbing rip­ples and small-scale festoon and trough cross­beds are common, but locally the beds arethin-bedded (l to 5 inches) and structureless.Manganese and iron oxide staining defines somebedding planes (Figure 15).

Analysis by XRD indicates that the Kuyken­dall tuffs contain approximately 50 to 60percent clinoptilolite, 30 percent montmoril­lonite, and up to 20 percent opal-CT. Minorunaltered volcanic glass and iron and manga­nese oxides are also present. zeotech Cbrpor­ation estimates reserves at over 700,000 shorttons of adsorbent clinoptilolite (50 to 60percent) on its leases covering over 2,300acres.

The paragenetic sequence of authigenicmineralization, from SEM, is unaltered vol­canic glass---> early smectite ---> clino­ptilolite ---> late smectite (Figure 16).smecti te occurs as porel ining , honeycombmasses coating volcanic glass and clinoptilo­lite. Clinoptilolite occurs as vug-filling,subhedral to euhedral, coffin-shaped laths.IYPical crystals are about 5 microns long and

100

Figure 15. stratified and cross-bedded clino­ptilolite-rich tuff at one of the Kuykendallpits. Manganese and iron oxides definebedding planes. Dark iron oxide blebs arepseudomorphic after pyrite.

Figure 16. Scanning electron micrograph ofclinoptilolite-rich tuff from one of theKuykendall pits. Wispy, pore-lining smectitecoats volcanic glass. Coffin-shaped clino­ptilolite laths have grown from the volcanicglass and smectite into the void. The clino­ptilolite has been partially etched and islocall y replaced by smectite.

3 microns wide ranging locally up to 17 mic­rons long and up to 10 microns wide. Poresolutions have partially dissolved some cline­ptilolite and have induced a second generationof smectite precipitation.

Buck Martin Q.1arry

The Buck Martin quarry is nearly circularand covers about 8 acres. Q.1arry faces exposeup to 8 feet of clinoptilolite-rich tuffsthe northeast walll they disappear insoutheast portion of the quarry (Figure 17).

Figure 17. Clinoptilolite-rich tuff exposedin the Buck Martin road metal quarry. The pitwalls have been recontoured since this photo­graph was taken in 1981. Note the crossbedding and flagging fracture in the ore.Geologic hammer is for scale.

The tuffs contain approximately 50 percentclinoptilolite, 30 percent montmorillonite,and up to 20 percent opal-CT. The clinoptilo­lite-rich tuffs are flaggy and containcolumnar jointing, crossbedding, and climbingripples. A sandstone with abundant mud clastsunderlies the tuffs. Smectitic clay 3 feetthick overlies the tuffs in the northeastsection of the quarry; 2 feet of black soiloverlies them in the north-west and centralpotions. Overburden thickness increasessouthward as the tuffs thin (Walton and Groat,1972) •

Henry Martin Quarry

The Henry Martin quarry is kidney-shapedand is 5 feet deep over 1 acre. At thequarry, clinoptilolite-rich tuffs break alongbedding or parting planes 4 to 10 inches.thick. No underlying beds are exposed, but asandstone unit adjacent to the quarry ap­parently dips under the tuffs (Walton andGroat, 1972). The lateral extent of the tuffsis unknown. OJerburden consists of 1 foot ofsmectitic, clayey soil. Vegetative cover isextensive.

DilIDrth Quarry

The Dilworth quarry has an areal extent ofabout 4.5 acres and up to 6 feet of relief(Walton and Groat, 1972). The thickness andlateral extent of the clinoptilolite-richtuffs are unknown because of lack of expo­sures. The flaggy tuffs break along partings1 inch thick. The Dilworth deposit has nooverburden. 1b the south, the tuffs disappearunder burrowed, smectitic clay, which gradesvertically into an overlying burrowed, tuffa­ceous sandstone (Walton and Groat, 1972).

101

MINERAIDGIC <XJ.1PARISOO' OF '!HE DEP<EITS

Table 1 lists the genetic classificationand some mineralogic characteristics of thesix zeolite deposits studied. Clinoptiloliteis the dominant zeolite at each deposit exceptDSV, where chabazite is dominant. Chabaziteis also dominant in the zeolitic tuffs of thenearby closed-hydrologic zeolite deposits atBear Springs and Bowie in southeast Arizona.An apparent reg ional trend of zeolite authi­genesis from abundant chabazite mineralizationin the southeast Arizona zeolite deposits topredominant clinoptilolite mineralization inthe New Mexico and Texas zeolite deposits isprobably not real. The precipitation of aparticular species of zeolite is more likelydictated by local diagenetic conditions, pore­solution chemistry, and parent-ash composi­tion.

The zeolites of all six deposits aremicrocrystalline, but those formed in theclosed-hydrologic systems at DSV, Buckhorn,and Casa Piedra are generally finer-grainedthan those formed in the open-hydrologic orhydrothermal systems at Cuchillo Negro,Tilden, and Foster Canyon (Table 1). Thezeolites in the closed-hydrologic systems maybe finer-grained because they had more distalash sources so the particles deposited in themwere smaller. Relatively small pores wereavailable for crystal growth after fine­sediment compaction in the subaqueous environ­ment. Relatively large pores were availablefor large clinoptilolite crystal growth in thecoarser, poorly sorted and poorly beddedFbster canyon tuffs.

The paragenetic sequence of authigenicmineralization at each deposit is quite simi­lar, except that the deposits exhibit varyingstages of authigenesis (Table 1). The DSVtuffs were altered mostly to chabazite bymoderately saline and alkaline lake waters.These waters were relatively Sio2-poor, had ahigh activity of H20, and had a low K to Na+Ca + Mg activity ratio, chemical conditionsthat inhibit the crystallization of high­silicon zeolites such as clinoptilolite, andlow-water zeolites such as analcime. Theseconditions persisted throughout the period ofzeolitization at IEV.

The pore solutions that altered theBuckhorn tuffs were more saline and alkalinethan those that altered the DSV tuffs. AtBuckhorn, alteration of the tuffs resulted inminor smectite with overlapping heulandite­group (including clinoptilolite) mineraliza­tion. Et:"ionite and analcime precipitated whenlocalized, concentrated, saline and alkalinesolutions reacted with the earlier, high­silicon zeolites.

There is a common paragenesis of· unalteredvolcanic glass ---) early smectite ---) clino­ptilolite ---) late smectite at the CuchilloNegro, Fbster canyon, casa Piedra, and Tilden

102

0.84

0.92

0.59

0.22

8.84

1.52

1.30

<0.02

73.90

<0.10

99.63

6.43

TildenCl?

11.50

0.7

2.4

0.6

1.7

5.65

(0.8)

68.4

TildenCit?

12.1

4-7 (b)

minor opal-cr,glass, clays

smectite,opal-cr

2.7

2.1

0.5

3.0

5.53

(1.5)

68.0

12.3

3-5 (b)5-10 (f)

glass,biotite,

feld.

3.70

0.26

0.60

2.04

0.10

8.89

1.69

1.63

<0.02

67.70

99.71

5.17

13.10

Casa Piedra Casa PiedraCl CIt

1.0

3.7

2.0

0.8

(1.5)

-5.53

12.3

glass,vrf

-68

3-6 (b)4-10 (f)

Foster CanyonCIt7

above. '!he assemblages probably formed undersimilar conditions of parent-ash composition,pore- solution chemistry, and diagenesis.

In addition to zeolite, the tuffs analyzedcontain varying amounts of impurities, in­cluding unaltered volcanic glass, clay min­erals, quartz, opal-CT, calcite, feldspar, andbiotite. Althotgh these analyses may resembleanalyses of the constituent zeolites, they arein fact analyses of rocks. Several composi­tional characteristics of the zeolitic tuffsare apparent.

0.04

0.05

0.24

3.31

1.04

2.81

3.32

0.88

8.77

5.12

<3.72**

12.65

64.72

Cuchillo NegroCl7

1.12

3.37

<0.02

1.33

5.20

<0.10

0.13

1.40

1. 70

63.40

99.71

12.20

traceclays

15.06

BuckhornCl

lcwer

traceclays

1.4

2.7

0.8

1.1

4.68

(1.3)

3-5 (b)5-10 (fl

56.6

12.1

BuckhornCIt

lcwer

DSVCb

?

rno.,tracequartz,traceclays

3.61

0.02 <0.02

L6VCb

rrain

0.05 <0.10

0.33 0.32

2.12 2.70

2.40 3.40

54.10 53.1

1.57 1.88

3.48 3.50

1.89 1.50

15.04 14.7

99.46 99.50

0.02

18.44 18.40

3.60

glass,quartz,calcite,feld.,clays

1

4.4

1.2

2.8

1.6

4

0.08

0.03

0.06

9.4

9.6

9.47

99.34

3.59

L6VCb

u

53.2

14.8

tracequartz,feld.,clay

1.96

0.02

2.80

2.09

0.06

2.18

0.37

2.50

54.17

15.29

0.91

18.79

101.14

3.54

glass,quartz,

calcite,feld.,clays

Parent-ash Dominant Dominant and Typical Paragenesis ofDeposit composition genetic system (suoordinate) zeolite phases1 grain size authigenic mineralization1 ,2

Dripping springs Valley rhyolitic closed-hydrologic Cb (Cl, Er) ~ 111 square Gl -> Srn(I/Srn), Cb

Buckhorn rhyodacitic closed-hydrologic Cl (He, Cb, Er, An, Mo) ~3lJ long G1 -> 8m --> CI , He --)Er, An -> Mag -> An

Cuchillo Negro unkn= open-hydrologic Cl (Cb) ~511 long G1 -> 8m -> Cb, crist,Cl-> Sm

Foster Canyon rhyolitic hydrothermal Cl (Cb, An) ~15 ~ long G1 -> 8m --> el, Opal-cr --> 8m

casa piedra unkn= closed-hydrologic Cl ~7~ long G1 -> 8m -> Cl -> 8m

Tilden intermediate open-hydrologic Cl ~5f1 long G1 -> 8m -> Cl --> 8m

Deposit LSVOre Cb

Oxide tuff main

cao

Si02

Al203

Fe203 (FeQx)

MgC

Impurities

Reference

References: 1) BOo'Iie (1985), 2) Zeotech Corp. files (unpub1.): 3) Sheppard and Gude (1982), 4) Krieger (1979).Note: DSV = Dripping Springs Valley; Cb = chabazite, Cl = cliroptilolite; mOo = mordenite; vrf = volcanic rock fragments; *WI = H20+ +~; ** includes

1.84% Fe203 and <1.88% Feox~ b = bound H20+; f = free H20+; t = Analyses of zeolite products--Turflite (Tilden), Clinolite 10 (Foster Canyon),Clinolite 15 (Casa Piedra), and Clinolite 20 (Buckhorn) as marketed by Zeotech Corp., Albuquerque, NM.

1 Cb = chabazite, Cl = clinoptilolite, Er = erionite, He = heulandite, An = analcime, Mo = nordenite2 G1 = unaltered volcanic glass, 8m = smectite, r/8m = mixed-layer illite/smectite, Mag = rragadiite, crist = cristo1:::alite

deposits. IDeal, differing diagenetic condi­tions proouced slight variations in progres­sion along the sequence, such as chabaziteprecipitation at Cuchillo Negro and FosterCanyon and opal-CT cementation at FosterCanyon and Tilden. The possible parageneticsequences of authigenic mineralization ofclosed-hydrologie, open-hydrologie, and hydro­thermal systems are quite diverse (Surdam,1977: Hay and Sheppard, 1977: Boles, 1977).Only slight variations in mineral assemblagesoccur amongst the four zeolite deposits listed

TabLe 2. Major-oxide chemical analyses as determined by X-ray fluorescence spectrometry of bulkzeolitic tuff samples from each of the zeolite deposits discussed in this report. Resultsreported in weight percent oxide. Lor determined at 9000 C (3) and 10000 C (1), others unknown.

T.ab~e 1. Genetic classification and some mineralogic characteristics of the six zeolite depositsdiscussed in this paper. Grain size was determined by SEM and refer.s to the dominant zeolitephase.

Ideal chabazite has a si:Al ratio of 2.0;chabazite from sedimentary environments ismore silicon-rich and has a Si:AI ratioranging from 3.0-4.1 (Sheppard and Gude,1975). The Si02 :Al 203 ratio of the four DSVchabazite-rich tuff samples ranges from 3.54to 3.61. Two of the four DSV samples show apredominance of alkaline-earths; the other twoare alkali-rich and sadic (Table 2).

The composition of natural clinoptiloliteis extremely variable. Clinoptilolite is moresilicon-rich and has a higher Si:Al ratio thanchabazite. The Si:Al ratio of clinoptiloliteranges from 2.7 to 5.0 and clinoptiloliteranges from completely calcic to dominantlyalkalic (Hay, 1966). There is a general in­crease in the Si02:Al 203 ratio of the clino­ptilolite-rich tuffs analyzed eastward fromthe low of 4.68 at Buckhorn. The ratio is5.12 at Cuchillo Negro, 5.53 at Fbster canyon,5.17 and 5.53 at casa Piedra, and reacheshighs of 5.65 and 6.43 at Tilden (Table 2).The increase in the ratio from New Mexico toTexas is probably coincidental when all vari­ables, such as regional tectonics, parent-ashcomposition, and local pore-solution chemistryare considered.

Sheppard and Gude (1982) report major­oxide chemical analyses for 16 clinoptilolite­rich tuffs of the western united States, in­cluding samples from Buckhorn, casa Piedra,and Tilden (Table 2). CXlly two of 16 samples,including Buckhorn, show a predominance ofalkaline-earth elements; the remainder show apredominance of alkalis. Three of the fiveclinoptilolite-rich tuffs we analyzed show,apredominance of alkaline-earths and are calcIc(Table 2). The Foster Canyon and Casa Piedratuffs are alkalic. The Foster Canyon sampleand one of the Casa piedra samples is potas­sic. The other casa Piedra sample is sodic.

CONCWSIONS

Geologic, petrologic, and mineralogiccharacteristics of zeoli tic tuffs were com­pared between six zeolite deposits in Arizona,Kew Mexico, and 'Iexas. The major conclusionsreached in this stu:1y are:

1. The IXipping Spring Valley (DSV) cha­bazite and Buckhorn clinoptilolitedeposits are two of several late ceno­zoic zeolite deposits formed inclosed-hyd rolog ic, lacustrine basinsin southeast Arizona and southwest KewMexico. The casa Piedra, 'Iexas clino­ptilolite also formed during theTertiary in a closed basin containinga playa lake.

2. Air-fall tuffs of the Cuchillo Kegro,New Mexico and Tilden, Texas clino­ptilolite deposits were zeoliticallyaltered by either percolating ground­waters in open-hydrologic systems or

103

by ponded, saline, alkaline solutions.The tuffs at Tilden were deposited inquiet lagoons behind barrier islands,and/or in associated coastal fluvialand washover fan environments.

3. Air-fall tuff was zeolitically alteredby low-temperature, Sio2-rich, hydro­thermal solutions in the Fbster canyonarea of the Tertiary Cedar Hills andSelden Hills volcanic-vent zone insouth-central Kew Mexico.

4. The dominant mineral of the zeolitictuffs at the six deposits is generallymicrocrystalline chabazite or clino­ptilolite. Typical impurities orassociated minerals inclu:1e: lithicfragments, unaltered volcanic glass,other zeolites, quartz, calcite, opal­CT, cristobalite, feldspar, evapo­rites, clays, and mafic minerals. Thedeposits exhibit varying stages ofauthigenic mineralization. A generalparagenetic sequence of unaltered vol­canic glass ---> early smectite and/ormixed layer illite/smectite ---> cha­bazite or clinoptilolite --->analcine, erionite ---> late-stagesmectite is indicated by SEM and thinsection analyses. Variations in thissequence were dictated by local diage­netic conditions, pore-solution chem­istry, and parent-ash composition.

5. There are two potentially commercial,chabazite-rich tuffs in ffiV. The mainzeolite tuff underlies about 1 squaremile of basin fill, is 0.25 to 1.74feet thick, and contains up to 90percent chabazite. The upper zeolitetuff underlies over 3 square miles ofbasin fill, averages 1.5 feet thick,and contains approximately 67 percentchabazite.

6. At the Buckhorn deposit, two clino­ptilolite-rich tuffs, separated byabout 20 feet of lacustrine mu:1stone,crop out for about 1 mile along strikeon the west side of D.lck Creek Valley.The lower zeolite tuff is 3 to 5 feetthick and contains up to 90 percentclinoptilolite. The upper zeolite tuffis I-foot thick and contains over 60percent clinoptilolite. The potentialfor commercial development is cur­rently being assessed.

7. Cuchillo Negro tuffs average approx­imately 50 percent clinoptilolite.The potential reserve base appears tobe large but is untested.

8. Foster Canyon tuffs contain up to 60percent zeolite and average 40 to 50percent clinoptilolite. Reserves aretentatively estimated at 200,000 to300,000 short tons of material aver­aging 50 percent clinoptilolite.

Corralitos Ranch Quadrangle, New Mexico:New Mexico Bureau of Mines and MineralResources Geologic Map 36, scale 1:24,000.

Cornwall, H. R., and Krieger, M. H., 1978,Geologic map of the El Capitan MountainQuadrangle, Gila and Pinal Counties,Arizona: u.S. Geological Survey Geologic<)..ladrangle Map GQ-1442, scale 1:24,000.

Edson, G. M., 1977, SOme bedded zeolites, SanSimon Basin, southeastern Arizona:Tucson, university of Ari zona, M.S.thesis, 65 p.

Eugster, H. P., 1970, Chemistry and origin ofthe brines of Lake Magadi, Kenya inMorgan, B. A., ed., Fiftieth anniversarysymposia: Mineralogy and petrology of theupper mantle. Sulfides, mineralogy andgeochemistry of non-marine evaporites:Mineralogical society of America SpecialPaper I'b. 3, p. 215-235.

Eyde, T. H., 1982, Zeolite deposits in theGila and san Simon Valleys of Arizona andNew Mexico, in Austin, G. S., comp., In­dustrial rockS-and minerals of the SOuth­west: New Mexico Bureau of Mines and Min­eral Resources Circular 182, p. 65-71.

Feth, J. H., 1964, Review and annotated bib­liography of ancient lake deposits (Pre­cambrian to Pleistocene) in the westernstates: u.S. Geolog ical Survey Bulletin1080, 119 p., 4 plates, scale 1: 2,500,000.

Gillerman, E., 1964, Mineral deposits ofwestern Grant County, New Mexico: NewMexico Bureau of Mines and Mineral Re­sources Bulletin 83, 213 p., 11 plates.

H:ty, R. L., 1966, Zeolites and zeoli tic reac­tions in sedimentary rocks: GeologicalSociety of America Special Paper 85, JJ3:op.

____~' 1977, Geology of zeolites in sedimen­tary rocks, in Mumpton, F. A., ed., Min­eralogy and geology of natural zeolites:Mineralogical SOciety of America ShortCourse I'btes, v. 4, p. 53-64.

__~~' 1978, Geologic occurrences of zeo­lites, in Sand, L. B., and Mumpton, F. A.,eds., Natural zeolites: occurrence, prop­erties, use: OXford, Pergamon Press, p.135-143.

Hay, R. L., and Sheppard, R. A., 1977, Zeo­1 i tes in open hydrolog ic systems, inMumpton, F. A., Mineralogy and geology ofnatural zeolites: Mineralogical SOciety ofAmerica Short Course I'btes, v. 4, p. 93­102.

Heindl, L. A., 1958, Cenozoic alluvial depos­its of the upper Gila River area, NewMexico and Arizona: Tucson, University ofArizona, Ph.D. dissertation, 249 p., 2plates, scale 1:500,000.

Jahns, R. H., 1955, Second day road log inSierra Cuchillo and neighboring areas inGuidebook of south-central New Mexico:New Mexico Geological SOciety, 6th FieldConference, p. 25-46.

104

Arizona r::.epartment of Mineral ReSJurces, 1978,Arizona zeolites: Mineral Report No.1,40 p.

Banks, N. G., and Krieger, M. H., 1977, Geo­log ic map of the Hayden Quadrangle, pinaland Gila Counties, Arizona: u.s. Geolog­ical Survey Geologic Quadrangle Map GQ­1391, scale 1:24,000.

Boles, J. R., 1977, Zeolites in low-grademetamorphic grades in Mumpton, F. A., ed.,Mineralogy and geology of natural zeo­lites: Mineralogical SOciety of AmericaShort Course Notes, v. 4, p. 103-135.Bowie, M. R., 1985, Geology of the Drip­ping Spring Valley chabazi te and relatedzeolite deposits in southeast Arizona andsouthwest New Mexico: SOcorro, New MexicoInstitute of Mining and Technology, M.S.thesis, 139 p., 2 plates.

Clemons, R. E., 1976, Geology of east half

9. The Casa Piedra tuff is 1 to 5 feetthick and averages about 60 percentclinoptilolite. Reserves are esti­mated at 100,000 short tons of mate­rial averaging 60 percent clinoptilo­lite. No commercial development hasoccurred.

10. Clinoptilolite-rich tuffs have beenmined from four quarries at the Tildendeposits. The three Kuykendall pitscover approximately 10 acres. Theycontain zeolitic tuffs 6 to 12 feetthick containing approximately 50 to60 percent clinoptilolite, 30 percentmontmorillonite, and up to 20 percentopal-CT. The Buck Martin quarrycovers about 8 acres. Quarry facesexpose up to 8 feet of zeolitic tuffswith composition similar to those inthe Kuykendall pits. 'Ihe H3nry Martinquarry is 5 feet deep and covers about1 acre. The Di 1 worth quarry is up to6 feet deep and covers about 4.5acres. The lateral extent of clino­ptilolite-rich tuffs exposed in lattertwo quarries is unknown.

11. The Si02:Al 20 3 ratio of four DSV cha­bazi te-rich tuff samples ranges from3.54 to 3.61. A general increaseoccurs in the Si02 :Al 20 3 ratio ofclinoptilolite-rich tuffs eastwardfrom the low of 4.68 at the Buckhorndeposit to the high of 6.43 at theTilden deposit; the Si02:A120 3 trendis probably coincidentaL TheSi02 :Al203 ratio of the tuffs is prob­ably dictated more by local diageneticconditions, pore-solution chemistry,and parent-ash composition than by awest-to-east change in magma sourcecomposition or tectonic influence.

FJahns, R. H., and others, 1978, Geologic sec­

tion in the Sierra Cuchillo and flankingareas, Sierra and Socorro Counties, NewMex ico in James, H. L., and others, eds.,Field guide to selected cauldrons andmining districts of the Datil-Mogollonvolcanic field, New Mexico: New MexicoGeological Society Special Publication N::>.7, p. 131-138.

Krieger, M. H., 1979, Zeolitization of Ter­tiary tuffs in lacustrine and alluvialdeposits in the Fay-San Manuel area, Pinaland Gila Counties, Arizona: U.S. Geolog­ical SUrvey Professional Paper 1124-D, 11p.

Maxwell, C. H., and Heyl, A. V., 1976, Pre­liminary geologic map of the Winston Quad­rangle, Sierra County, New Mexico: U.S.Geological survey Open-File Report 76-858,scale· 1: 24,000.

MCGrath, D. A., 1985 (in press), Zeolites in ahydrothermal system, Foster Canyon, IDnaAna County, New Mexico: Socorro, NewMexioo Institute of Mining and Technology.

Munson, R. A., and Sheppard, R. A., 1974,Natural zeolites: their properties,occurrences, and uses: Minerals, SCienceand Engineering, v.6, p. 19-34.

Olander, P. A., 1979, Authigenic mineral reac­tions in tuffaceous sedimentary rocks,Buckhorn, New Mexico: laramie, Universityof Wyoming, M.S. thesis, 82 p.

Scarborough, R. B., and Peirce, H. W., 1978,Late Cenozoic basins of Arizona inCallender, J. F., and others, ed., Land ofCochise southeastern Arizona: New MexicoGeological Society Guidebook, 29th FieldConference, p. 253-259.

Seager, W. R., 1973, Resurgent volcano-tec­tonic depression of Oligocene age, south­central New Mexico: Geological 8Jciety ofAmerica Bulletin, v. 84, # 11, p. 3611­3626.

Seager, W. R., and Clemons, R. E., 1975, Mid­dle to late Tertiary geology of CedarHills-Seldon Hills area, New Mexico: NewMexico Bureau of Mines and Mineral Resour­ces Circular 133, 23 p.

Seager, W. R., Hawley, J. W., and Clemons, R.E., 1971, Geology of the San Diego Moun­tain area, IDna Ana County, New Mexico:New Mexico Bureau of Mines and MineralResources Bulletin 97, 36 p.

Sheppard, R. A., 1971, Clinoptilolite ofpossible economic value in sedimentarydeposits of the conterminous UnitedStates: U.S. Geological Survey Bulletin1332-B, 15 p.

, 1973, Zeolites in sedimentary rocks,--l"-"n- Lefond, S. J., ed., Industrial Minerals

and Rocks: New York, American Instituteof Mining and Metallurgical Engineers, p.1257-1270.

Sheppard, R. A., and Gude, A. J., 1968, Dis­tributions and genesis of authigenic sili­cate minerals in tuffs of Pleistocene lakeTecopa, Inyo County, California: U.S.Geological Survey Professional Paper 597,38 p.

Sheppard, R. A., and Gude, A. J., 3rd, 1975,occurrence, properties, and utilization ofchabazite from sedimentary deposits in theUnited States, in Bailey, S. W., Proceed­ings of the International Clay Conference:Wilmette, Illinois, Applied PublishingLtd., p. 565.

Sheppard, R. A., and Gude, A. J., 3rd, 1982,Mineralogy, chemistry, gas adsorption, andNH4+ --exchange capacity for selectedzeolite tuffs from the western UnitedStates: U.S. Geological Survey q;>en-FileReport 82-969, 16 p.

Sheppard, R. A., and Mumpton, F. A., 1984,Sedimentary fluorite in a lacustrine zeo­litic tuff of the Gila Conglomerate nearBuckhorn, Grant County, New Mexioo: Jour­nal of sedimentary Petrology, v. 54, n. 3,p. 853-860.

Surdam, R. C., 1977, zeolites in closed hydro­logic systems, in Mumpton, F. A., ed.,Mineralogy and geology of natural zeo­lites: Mineralogical Society of AmericaShort Course N::>tes, v. 4, p. 65-91.

Walton, A., and Groat, C. G., 1972, Zeolitesin Texas: Texas Bureau of Economic Geolo­gy Open-file Report, university of Texasat Austin, 46 p.

105

..._-------------_.-

Geology and Industrial Usesof Arizonas Volcanic Rocks

John W. welty and Jon E. SpencerArizona Bureau of Geology

and Mineral Technology845 N. Park Ave.

Tucson, M. 85719

Arizona's volcanic-rock sequences arestill incompletely known, particularly incentral and western Arizona. The potentialfor recognition and exploitation of importantnew deposits of useful volcanic materials ishigh.

INTROCUCTION

Six episodes of volcanism are recogniZedin the geologic history of Arizona. Theseepisodes have unequally affected all three ofArizona's geologic-physiographic provinces:Colorado Plateau, Transition Zone, and Basinand Fange Province (Peirce, 1984). \blcanism·in these terranes has produced a diversity ofvolcanic rocks some of which have utilitarianuses. In many cases geographic distributionhas determined their usefulness.

The earliest volcanic episode in Arizonaoccurred during the Proterozoic between 1.8and 1.6 b.y. ago, and was one of the processesthat resulted in formation of the continentalcrust that underlies the State. Volcanicrocks formed during this time are most widelyexposed in the Transition Zone and parts ofthe Basin and Range Province (Figure 1).Proterozoic volcanic rocks are products of twodistinct generations of volcanism that togeth­er are characteristic of Precambrian "green­stone belts" in many other parts of the world.The older part involves a primitive bimodalsuite of tholeiitic basalt and rhyodacite thatwas built upon a mafic basement of oceaniccharacter (Anderson, 1986). '!his activity ·wasfollowed by a period of submarine calc-alka­line mafic volcanism, which was succeeded bysubmarine to subaerial alkali-calcic felsicvolcanism (Anderson, 1986). A second episodeof Proterozoic volcanism occurred about 1.2 to1.1 b.y. ago, but was more areally restrictedand less voluminous than the previous episode.This younger period of volcanism is represent­ed by basal t flows and rhyol i te tuffinterbedded with sedimentary rocks of the·Apache Group near Globe and the Unkar Group ofthe Grand canyon (Figure 1).

In the early Mesozoic, volcanic activityis first evidenced by volcanic ash and detri­tus deposited in the Upper Triassic ChinleFormation (Colorado Plateau) from eruptivecenters to the south and west (Peirce, 1986).By Jurassic time, volcanism was widespread in

106

ABSTRACT

Volcanic activity occurred during sixperiods of Arizona's geologic history. Pre­cambrian volcanism occurred in two pulses at1.8-1.6 billion years (b.y.) ago and at 1.2-

·1.1 b.y. ago. Volcanism occurred again inmid-Jurassic and Laramide (Late Cretaceous­early Tertiary) time. Volcanic rocks fromthese times are not used commercially in anysignificant quantity. Middle and late ceno­zoic magmatic activity covered large areas ofArizona with voluminous volcanic rocks. Dur­ing the mid-Tertiary magmatic pulse, explosivesilicic magmatism, with eruption of areallyextensive ash-flow tuffs, covered large areasin the Basin and Range Province, while theCblorado Plateau remained largely unaffected.Basalt eruption also occurred during and imme­diately after silicic volcanism, leading tocompositionally diverse suites of volcanicrocks. Late Cenozoic volcanism occurredthroughout Arizona and was dominated by wide­spread eruption of basalt flows with localcinder-cone clusters and siliceous volcanicdeposits.

Perlite deposits near Picketpost Mountainin northeastern pinal County account for thebulk of the industrial uses of mid-Cenozoicvolcanic rocks. Other perlites of presumedmiddle Tertiary age are present in central,southeastern, and western Arizona, but to dateremain unexploited. Arizona Fire Agate is avaluable gem material and is associated withvolcanic rocks of middle Tertiary age. Basal­tic rock of this age also is utilized in themanufacture of rock wool for inSUlation.

late cenozoic volcanism produced most ofthe industrial-quality volcanic rocks. Ba­salt, cinder cones, and materials of rhyoliticcomposition are commercially exploited bymunicipal and Federal agencies and privateindustry for aggregates, road conditioners andmaintenance materialS, asphaltic concretes,cinder block construction, pozzolans, andlandscaping. These deposits are generallyconfined to the Flagstaff and Springervilleareas. A famous peridot gem locality is asso­ciated with late Tertiary basalts at PeridotMesa on the San Carlos Indian Reservation.Important products derived from altered vol­canic materials of late cenozoic age includeclay and zeolite.

Figure 1. outcrops of metamorphosed Precam­brian volcanic rocks formed during the first(1.8-1.6 b.y.) episode are shown in black.Outcrops of rocks formed during the secondepisode (1.2-1.1 b.y.) are too small to showindividually, but occur in the Unkar Group inthe Grand Canyon area (GC) and the ApacheGroup near Globe (AG) as interbeds. Geologyfrom Anderson (1986).

Figure 2. outcrops of Jurassic volcanicrocks. Modified from S. J. Reynolds (written

communication, 1986).

a northwest-trending belt that traversed Ari­zona from Ibuglas to Parker (Figure 2). Ju­rassic volcanic rocks are composed of daciticto rhyolitic ash-flow tuffs, air-fall tuffs,flows, and flow breccias; andesitic volcanicsare less common.

Illring laramide (Late cretaceous to early'Iertiary) time another belt of magmatism ap­peared and migrated eastward across Arizona.Volcanic rocks of this age are most widelypreserved in southeastern Arizona (Figure 3).This volcanic episode resulted in the con­struction of andesitic stratavolcanoes andandesitic to rhyolitic caldera complexes.Remnants of these calderas are present in theSilver Bell, 'Dlcson, am santa Rita Mountainsoutside 'Dlcson (Lipman and sawyer, 1985).

107

Figure 3. outcrops of Late Cretaceous toearly Tertiary (Laramide) volcanic rocks.Modified from Keith (1984).

Middle and late Cenozoic magmatic activi­ty occurred over large areas of Arizona andproduced voluminous quantities of volcanicrocks. DJring the mid-Tertiary magmatic pulse(Figure 4) explosive silicic magmatism pro­duced extensive ash-flow tuffs that coveredlarge portions of the Basin and Range Provincewhile the Colorado Plateau remained largelyunaffected. Volcanic flows and volcaniclasticsediments and areally restricted lahars andair-fall tuffs were also produced. Some ofthese rock types are associated with ventareas that locally include shallow-level in­trusives that might have been situated beneathvolcanoes.

Unlike many other areas of the worldwhere this type of silicic volcanism is occur­ring today, such as the Andes of South Ameri­ca, the Basin and Range Province of Arizonaand the Southwest underwent major crustalextension and normal faulting during vol­canism. As a result, mid-Tertiary volcanicfields in Arizona were slightly to severelybroken by faults and dismembered during orshortly after volcanism. Basalt eruption alsooccurred during and immediately after silicicvolcanism, which produced compositionally di­verse suites of volcanic rocks. In additionto structural and geochemical diversity andcomplexity, variable and locally intense hy­drothermal alteration characterizes Arizona'smiddle Ceno3Jic volcanic rocks.

Late Cenozoic volcanism in Arizona isdominated by areally extensive basalt flowsthat are most widely exposed in the TransitionZOne and along the southwestern margin of theColorado Plateau, but includes cinder conesand local siliceous volcanic deposits (Figure5). siliceous volcanic rocks of this age arealmost entirely restricted to the san Francis­co volcanic field in the vicinity of Flag­staff. The most recent basaltic volcanism(less than 1-2 m.y. old) has been largelyrestricted to the San Francisco, Springer­ville, and Uinkaret volcanic fields of theCblorado Plateau and the sentinel, san Bernar­dino, and San Carlos volcanic fields of theBasin and Range Province. structural disrup­tion of these rocks is minor to non-existent,and evidence of hydrothermal alteration issparse •

INOOSTRIAL USES OF' VOLCANIC ROCKS

Of the six volcanic episodes, only themid-Tertiary and late Cenozoic events producedrocks that are substantially exploited today.\blcanic rocks of Precambrian and Jurassic agehave been so metamorphosed that they have lostmost of the unique properties possessed byvolcanic rocks and are best considered meta­morphic rocks. SChist derived from metamor­phosed rhyoli te near Mayer is mined for dimen­sion stone and used in the construction indus­try as building facade. The qualities that

108

made this material attractive are the resultof metamorphism rather than original volcanicprocesses. Jurassic and Laramide volcanicrocks also have commonly undergone consider­able hydrothermal alteration and structuraldeformation. As a result volcanic rocks fromthese time periods are generally too unliketheir volcanic protoliths to have been quar­ried for industrial uses. Cbnversely, becauseof their widespread distribution and generallyfresh to slightly altered condition, middleTertiary and late Cenozoic volcanic rocks areused by industry where properties unique tovolcanic rocks are required.

A variety of middle Tertiary volcanicrocks are used commercially, with those ofsilicic composition being the most important.Perlite, a rhyolitic glass that contains aconcentric "onion-skin" structure caused bycooling and hydration, is present in manyparts of the Basin and Range Province. Theterm "perlite" has been used traditionally todescribe any naturally occurring volcanicglass that expands when heated to yield afrothy, lightweight cellular substance similarin some aspects to popcorn. Perlite withexcellent expansion (popping) capabilitiescommonly has the follow ing properties: (1)shiny luster; (2) onion-skin texture; (3) fewvisible crystals; (4) presence of marekanites;(5) specific gravity of approximately 2.4g/cc; and (6) 3 to 4 percent water by weight(Wilson and Roseveare, 1945). Marekanites,obsidian nodules known locally as "Apachetears," are small areas of the rhyolitic glassthat lack the onion-skin texture (Figure 6).

In 1984 U.S. production of both processedand expanded perlite increased to reverse a 6­year decline. Nationwide, 653,000 tons ofperlite was mined in 1984 with New Mexicoaccounting for 87% of the total; of the sixstates mining perlite, Arizona ranked thirdafter ~w Mexico and california (Burgin, 1985;Meisinger, 1985). We estimate that Arizonaaccounted for 6% of the Nation's total perliteproduction. Nationwide, processed (not ex­panded) perlite sold and used amounted to498,000 tons valued at slightly more than$16.6 million ($33.41/ton) while sales ofexpanded perlite totaled 404,000 tons with avalue of $69.5 million ($172/ton) (Meisinger,1985). The perlites of Arizona have beenhistorically and are currently used for light­weight and high-strength aggregate, agricul­tural fertilizer carrier, fire-retardant insu­lation, acoustical and perlite-gypsum plaster,filtering in the beverage, chemical, pharma­ceutical and sugar industries, soil condi­tioner, chicken 1i tter, molding for foundrysands, and filler for paints and plastics.

EXtensive deposits of perlite are exposedat many places within a northwest-trendingbelt approximately 15 km long by 4 km widelocated adjacent to picketpost Mountain south­west of Superior in Pinal County. These de-

II

1-350

II

III

:."" -340

~.\

MI 0 50 1001-1.."~'i-1j'c-",r-"r-,--"--'-'-,-,__---I'

KM 0 50 100

DISTRIBUTION OF MID-TERTIARY (40-15 m.y.) VOLCANIC ROCKS

Basalt or basaltic andesite flows.

Dominant Iy andesitic volcanicrocks.

Silicic volcanics (rhyolites,dacites, minor andesites.

Volcanic rocks, undivided.

Figure 4. outcrops of middle Tertiary volcanic rocks. Modified from SCarborough (1986).

109

Basaltic volcanics (2 -10 m.y.)

Basaltic volcanics (4 -15 m.y.)

110

DISTRIBUTION OF UPPER CENOZOIC (0-15 m.y.)VOLCANIC ROCKS AND VOLCANIC FIELDS

Basaltic volcanics (0 - 4 m.y.)

Silicic volcanics (0-4 m.y.)

Figure 5. Outcrops of late Cenozoic volcanic rocks. Modified from Scarborough (1985).

Figure 6. Marekanites (black spots) or"Apache Tears" in a gray matrix of perlitefrom the Sil-Flo perlite pit southwest ofSuperior. Photo by John W. Welty.

pos i ts are of importance because of presentcommercial development and potential reserves(Peirce, 1969). '!he geology of the PicketpostMountain area is described by Iamb (1962) andPeterson (1966).

Middle Tertiary rhyolite lava flows coverthe low-lying hills from the northern tosoutheastern side of picketpost Mountain. '!herhyolite is underlain by Precambrian pinalSChist and Apache Gtoup metasedimentary rocks,middle Tertiary tuff with local basalt flows,and a volcanic breccia composed of angularfragments of both Precambrian and middle Ter­tiary lithologies in a pyroclastic matrix.within the flow-banded rhyoli tes is a 2-15 mthick layer of perlite that locally exceeds200 m in total thickness. CNerlying the per­lite is a similar thickness of non-perliticglassy rhyolite, tuff, and quartz latiteflows. This package of volcanic rocks islargely flat-lying. The perlite appears tothin westward and northward. '!he commerciallyexploited perlite is light gray to milky whitewith strongly developed spheroidal perliticstructure and a vitreous luster. Spheroidalmarekanites are scattered through the perliteand collecting them is a local tourist attrac­tion.

Anderson and others (1956) describe theperlite as containing 90% glass with plagio­clase, k-feldspar, magnetite and quartz cut byveinlets of cristobalite and pyrolusite.Chemically the perlite ore is high in silica(>70 weight percent), low in iron and alkalineelements, and contains less than 10 weight­percent total alkali elements (Anderson andothers, 1956). The perlite contains 3.8­weight-percent water, whereas the marekaniteshave a very low water content (Keller andPickett, 1954).

111

Although other occurrences of potentiallyexpandable volcanic glass in middle Tertiaryvolcanic rocks of Arizona (see Elevatorski,1978; Jaster, 1956) offer opportunities forfurther development, Peirce (1969) suggeststhat the Superior area is best suited forfuture growth in the Arizona perlite industrybecause of its developed infrastructure andaccess to major transportation corridors.Reserves, however, appear to be limited.

Other uses of middle Tertiary volcanicrocks include the following: (1) pumice minedby the Gila Valley Block Cbmpany northeast ofSafford for the fabrication of lightweightconcrete block; (2) similar deposits nearKirkland in central Arizona that were crushedand sized for the production of cat litter;(3) an opaque opal known as Fire Agate inrhyolitic tuff near Klondyke, Graham Cbunty;and (4) basalt southwest of Casa Grande thatis used in the manufacture of rock-wool insu­lation products.

Upper Cenozoic volcanism resulted in thedevelopment of numerous cinder cones, particu­larly on the Cblorado Plateau. The san Fran­cisco volcanic field contains at least 200cinder cones, many with one or more associatedlava flows and, one important center of silic­ic volcanism (Figure 7). Flows and cones havebeen divided on the basis of stratigraphic andphysiographic relationships, degree of weath­ering and erosion, K-Ar ages, and chemical andpetrographic data into five groups ranging inage from Holocene (A.D. 1064) to Pliocene (6m.y. ago) (Damon and others, 1974; Moore andothers, 1976; smiley, 1958).

'!he flows and cones are mostly nepheline­normative alkali olivine basalts that, withdecreasing olivine content, grade into alkali­rich high alumina basalts. With relativeenrichment of potassium and silica, alkaliolivine basalts also grade into basaltic ande­sites. Silicic volcanic rocks consist largelyof rhyodacite domes, flows and minor pyro­clastic deposits. Basaltic and silicic erup­tions were closely associated in space andtime. Chemical data from both mafic and si­licic rocks suggest that all volcanic rockswere erupted from the same magma source thathas experienced a complex evolutionary histo­ry. strontium isotope ratios are generallylow «0.7050), implying that the lavas weregenerated in the mantle and were not signifi­cantly contaminated by crustal material (Mooreand others, 1976).

The major center of commercial productionof cinders has been from the cinder cones ofthe San Francisco volcanic field. SuperliteBuilders Supply obtains cinders from a. pitnear Winona; Flagstaff Cinder sales.froffi.aquarry in East Flagstaff; Olson Brothers froma quarry in Williams; the Coconino> CountyHighway D3partment from several pits; the U.S.Forest Service from many quarries; and theArizona Department of Transportation from

I',!

Figure 7. Geologic map of the San Francisco volcanic field near Flagstaff showing the locationof cinder cones and major cinde~producing facilities. Modified from Ulrich and others (1984).

1N

R.-IO- E.

Int40

vice produce cinders for industrial use fromthe Springerville volcanic field (Figure 5).Past production has come from several smallquarries in the san Bernardino volcanic fieldin southeastern Arizona (Figure 5). We esti­mate that in 1983 cinder production in Arizona

112

CinderSales Pk

Qsv.~

Flagstaff

EXPLANATION

111°30'

5"====="",,,==<:====~0~======~5==============,,;.10, miles

5"""=>==="",,,0~====~5=========ia10. ki lometers

Tertiary (Pliocene) mafic volcanics.

Paleozoic sedimentary rocks, undivided.

Quarry.

Kaibab Fm. (Lower Permian).

Quaternary (Pleistocene) silicic volcanics.

Fault, bar and ball on downthrown side.

Cinder Cones.

Quaternary (Holocene - Pleistocene) mafic volcan ics.

Quaternary alluvium.

*

several pits. These companies and agenciesaccount for the bulk of commercial and non­commercial production of cinders from the sanFrancisco volcanic field (Figure 7). PerkinsCinders, the Apache County and Navajo CountyHighway D3partments, and the u.s. rarest ser-

Mexico Bu,reausources J:$1,;1.L.L.t:!l::.UI

REFERENCES

CONCWSION

of water, it is subject to al teration to po­tentially useful products. Two of these prod­ucts, bentonite clay and the zeolite mineralchabazite, are mined in Arizona and exportedfor use elsewhere (See Eyde and Eyde, thisvolume; Ibwie, this volume). The Ibwie chaba­zite deposit of southeastern Arizona, also oflate Cenozoic age, is mined for use as anactivated molecular-sieve material (Eyde,1978) •

ACKNCWLEDSMENTS

Arizona has experienced a complex vol­canic history that has intermittently spanned1.8 b.y. of geologic time. Volcanic rocks ofPrecambrian to Laramide age have not beensignificantly used in commerce as their physi­cochemical characteristics are not yet knownto meet the specifications required for spe­cial use. Widespread and voluminous volcanicrocks and related products of middle and lateCenozoic age are used by industry in Arizonaand outside the State. 'Ibe variety of commer­cial products includes perlite, pumice, ba­salt, basaltic cinders, pozzolan, semi-pre­cious gem stones, clays, and zeolites. Thetotal value of these products in 1984 is esti­mated to have been in excess of $3 million.Although the use of Arizona's volcanic rocksis currently limited, volcanic-rock sequencesin Arizona are still incompletely known andthe potential for recognition and exploitationof important new deposits of useful volcanic­related commodities is high.

Allen, J. E., and Balk,resources of Fort U::::J.. .1. eu II..""

We thank H. Wesley Peirce of the ArizonaBureau of Geology and Mineral Technology(ABGMT) for his guidance and encouragement toventure into the world of industrial mineralsand rocks, and for the opportunity to takepart in the Forum. Steve Reynolds, ABGMT,provided helpful advice about the volcanichistory of Arizona, and John Challinor pro­vided information on the Arizona Tufflite,Inc. operations.

Anderson

amounted to approximately 600,000 tons. Inall of these areas, the cinders display a widevariety of colors from black to magenta. 'Ibedistribution of and differences among thecolor tyPes are not well understood, althoughthe color variation is thought to reflectdifferences in the oxidation state of iron inthe magmas from which cinder cones are pro­duced. Peirce (this volume) cites an examplewhere cinder color was of practical impor­tance. Arizona cinders are mined for use asrip-rap, cinder block, aggregate for road baseand asphaltic concretes, drilling-moo condi­tioners, drainage fields for septic systems,winter traction on icy roads, and landscaping.

In the san Francisco volcanic field, theSugarloaf Mountain rhyolite dome erupted ap­proximately 210,000 years ago (D:unon and oth­ers, 1974). 'Ibis eruption produced a layer ofrhyolitic tuff that yielded over 200,000 tonsof pumice used as pozzolan in the constructionof Glen Canyon Dam. Currently the material(different locality) is sold as lightweightaggregate and for landscaping, and ArizonaTufflite, Inc. (Figure 7) is marketing it foruse as a pozzolan. Pozzolans are siliceousmaterials that, when finely ground (to -325mesh), will form a "natural" cement in thepresence of water and lime. Other pozzolansare found near Williams in upper Cenozoicrocks and near Bouse and Safford in mid-Ter­tiary rocks (Williams, 1966).

Basalt on Peridot Mesa in the san carlosvolcanic field (Figure 5) also contains pe­ridot (gem-quality olivine) that is intermit­tently sold to rock collectors and stone cut­ters for mineral specimens and jewelry (Mooreand VUich, 1977). Peridot Mesa, approximately14 km2 in area, is capped by a Pleistocenebasal t flow that is 3 to more than 30 m thickand is underlain by flat-lying tuff, silt­stones, and gravels of Plio-Pleistocene age(Bromfield and Shride, 1956; Lausen, 1927).The peridot occurs as aggregated inclusions ina basalt flow that erupted from a dike sourceat the southwest corner of Peridot Mesa.Bromfield and Shride (1956) report that anexposure of basalt in Peridot canyon containsa layer ranging from 2-4 m thick that containsan unusually high concentration of peridot.Peridot occurs in aggregates or masses thatcomprise 25-40 percent of the rock volume andaverage from 7-20 em in maximum diameter.Peridot also occurs in Buell Park on theNavajo Indian Reservation north of Ft.Defiance (Figure 4; Allen and Balk, 1954). In1984 Arizona led the Nation in gem-stone pro­duction with total production valued at $2.7million; turquoise and peridot, respectively,were the most important contributors (Burgin,1985). TOtal peridot production has beendeclining for several years (pressler, 1985).

Many volcanic eruptions are accompaniedby explosive outpourings of volcanic ash.,When ash is deposited in a lake or other body

Id

I.

m

113

Anderson, Phillip, 1986, Summary of the Pro­terozoic plate tectonic evolution of Ari­zona from 1900 to 1600 Ma, in Beatty,Barbara, and Wilkinson, P. A:-K., eds.,r'rontiers in geology and ore deposi ts ofArizona and the SOuthwest: Arizona GeOlo­gical SOciety Digest, v. 16, p. 5-11.

Bromfield, C. S., and Shride, A. F., 1956,Mineral resources of the san carlos IndianReservation, Arizona: U.S. GeologicalSurvey Bulletin 1027-N, p. 613-689, scale1:250,000.

Burgin, L. B., 1985, The mineral industry ofArizona, in Minerals Yearbook 1984: v. II,Area reports, domestic: U.S Bureau ofMines, p. 65-85.

Damon, P. E., Shafiqullah, M., and Leventhal,1974, K-Ar chronology for the San Francis­co volcanic field and rate of erosion ofthe Little Colorado River, in Karlstrom,T. N. V., and others, eds:;- Geology ofnorthern Arizona, with notes on archaeolo­gy and paleoclimate: pt. 1, regional stu­dies: Geological SOciety of America,RJcky Mountain section Meeting, Flagstaff,Ariz., 1974, p. 221-235.

Elevatorski, E. A., 1978, Arizona IndustrialMinerals: Arizona ])apartment of MineralResources Mineral Report ID. 2, 70 p.

Eyde, T. H., 1978, Bowie Zeolite: an Arizonaindustrial mineral: Arizona Bureau ofGeOlogy and Mineral Technology Fieldnotes,v. 8, no. 4, p. 1-5.

Jaster, M. C., 1956, Perlite resources of theUnited States: U.S. Geological SurveyBulletin 1027-1, p. 375-403.

Keith, S. B., 1984, Map of outcrops of Lara­mide (Cretaceous-Tertiary) rocks in Ari zo­na and adjacent regions: Arizona Bureauof GeOlogy and Mineral Technology Map 19,scale 1: 1,000,000.

Keller, W. D., and Pickett, E. E., 1954, Hy­droxyl and water in perlite from Superior,Arizona: American Journal of SCience, v.252, no. 2, p. 87-98.

Lamb, D. C., 1962, Tertiary rocks south andwest of Superior, Arizona,in Weber, R. H.,and Peirce, H. W., eds., Guidebook of theMogollon Rim Region, east-central Arizona:New Mexico Geological SOciety Guidebook,13th Field Q:>nference, p. 149-150.

Lausen, Carl, 1927, OCcurrence of olivinebombs near Globe, Arizona: American Jour­nal of Science, 5th ser., v. 14, p. 292­306.

114

Lipman, P. W., and Sawyer, D. A., 1985, Meso­zoic ash-flow caldera fragments in south­eastern Arizona and their relationship toporphyry copper deposits: Geology, v. 13,p. 652-656.

Meisinger, A. C., 1985, Perlite, in MineralsYearbook 1984: v. I, Metals andminerals:U.S. Bureau of Mines, p. 701-703.

Moore, R. B., Wolfe, E. W., and Ulrich, G. E.,1976, Volcanic rocks of the eastern andnorthern parts of the San Francisco vol­canic field, Arizona: Journal of Researchof the U.S. Geological Survey, v. 4, no.5, p. 549-560.

Moore, R. T., and Vuich, J. S., 1977, Anevaluation of the olivine resources of theSan Carlos Apache Indian Reservation andrecommendation for potential development:Arizona Bureau of Mines unpublished re­port, 27 p.

Peirce, H. W., 1969, Perlite, in Mi~eral andwater resources of Arizona: Arlzona Bu­reau of Mines Bulletin 180, p. 403-407.

1984, '!he Mogollon escarpment: Arizona---

Bureau of Geology and Mineral TechnologyFieldnotes, v. 14, no. 2, p. 8-11.

_---::--,1986, Paleogeographic linkage betweenArizona's physiographic provinces, inBeatty, Barbara, and Wilkinson, P. A. K.,eds., Frontiers in geology and ore depos­its of Arizona and the SOuthwest: ArizonaGeological SOciety Digest, v. 16, p. 74­82.

Peterson, D. W., 1966, The geology of Picket­post Mountain, northeast Pinal County,Arizona: Arizona Geological Society Di­gest, v. 8, p. 159-176.

Pressler, J. W., 1985, Gem Stones, in MineralsYearbook 1984, v. I, Metals and minerals:U.S. Bureau of Mines, p. 391-404.

Scarborough, R. B., 1985, Map of post-15-m.y.volcanic outcrops in Arizona: ArizonaBureau of GeOlogy and Mineral TechnologyMap 21, scale 1:1,000,000.

1986, Map of mid-Tertiary volcanic,--...."......

plutonic, and sedimentary rock outcrops inArizona: Arizona Bureau of Geology andMineral Technology Map 20, scale1: 1,000,000.

smiley, T. L., 1958, '!he geology and dating ofSunset Crater, Flagstaff, Arizona: NewMexico Geological SOciety Guidebook, 9thField Conference, p. 186-190.

II d

..,-----------------------~~~=

Ulrich, G. E., Billingsley, G. H., Hereford,Richard, Wolfe, E. W., Nealey, L. D., andsutton, R. L., 1984, Map showing geology,structure, and uranium deposits of theFlagstaff 10 x 20 quadrangle, Arizona:U.s. Geological Survey Miscellaneous In­vestigations Series Map 1-1446, scale1:250,000.

williams, F. S., 1966, Potential pozzolandeposits in Arizona: Tucson, Universityof Arizona, M.S. Thesis, 93 p.

Wilson, E. D., and Roseveare, G. H., 1945,Arizona perlite: Arizona Bureau of MinesCircular 12, 10 p.

115

IIIIIIIIIIIId..' _

Locating l Sampling l and EvaluatingPotential Aggregate Deposits

Leo LanglandArizona Department of Transportation

AOOT, 206 S. 17th Ave.,Mail rrop 127A

Phoenix, AZ 85007

ABSTRACT

One of the primary functions of the Geo­technical Services-Materials/Section of theArizona Department of Transportation (AIXJr) islocating, sampling, and evaluating potentialaggregate deposits thrOl..ghout the state. Thisinformation is essential in designing, esti­mating, and bidding highway constructionprojects.

The nature of materials used for aggregatevaries greatly within Arizona. The north­eastern or plateau section is famous for itsscenic sedimentary formations that are, how­ever, too soft to make suitable aggregate.Volcanic materials are widely used in place ofmore conventional geologic units. In con­trast, the southwestern, or Basin-and-Rangesection, contains a relative abundance of goodaggregate, especially a diversity of gravels.

The paper will review the office, field,and laboratory methods used by the AOOr Mate­rials Section in satisfying its needs foraggregate information in Arizona.

INTRODUCTION

A primary function of ADOT, MaterialsSection, Geotechnical Services, is locating,sampling and evaluating potential mineralaggregate deposits so that the information isavailable for use in designing, estimating,and bidding future highway construction pro­jects in Arizona. The purpose of this paperis to review some of the methods used inaccomplishing this function.

GEOLOGIC SETTING or' AGGREGATES

Geologically, the State of Arizona iscomposed primarily of two major structuralprovinces: (1) the Cblorado Plateau Provincein the north and northeast portion, and (2)the Basin and Range Province in the south andwest portion. In general, the type of aggre­gate found and util ized wi thin the Statevaries with the province.

Cblorado Plateau province

The Colorado Plateau (CP) Province, ingeneral, consists of gently dipping sedimen­tary formations that have been intruded andcovered by igneous rocks in the volcanic

116

fields surrounding the towns of Flagstaff andspringerville. Except for exposures in theGrand Canyon and along the Mogollon Rim es­carpment, most of the exposed sedimentaryformations are Permian or younger in age.Unfortunately, most of these younger forma­tions consist of soft shales, siltstones andsandstones, and are not conducive to thedevelopment of either durable gravels orcrushed rock. As a consequence, most of theaggregates from the CP are quarried fromselected rock types such as basalts, felsites,limestones, sandstones, and cinders.

Hard durable basalt is considered an ac­ceptable aggregate. The only exceptions arewhen it contains basaltic natural glass,nodules of tridymite or cristobalite silica,or clays that are reactive with the alkal iesin Portland cement. Also, a blend sand isusually required because the crushed and shotfines often are too plastic. ,Basalt has ahigh affinity for bitumen therefore is excel­lent in preventing the stripping of asphalticconcrete pavements.

Light-colored, fine-grained igneous rocksare collectively known as felsites. Thefelsite group includes andesite, rhyolite,dacite, and trachyte. Although usually hardand durable, they commonly contain silicaglass, opal, and chalcedony, all of which arereactive to Portland cement. Also, they arecommonly hydrophilic (high water absorptionability) and have low bitumen absorption prop­erties. Another problem is flow structure,which causes felsites to fracture in thecrusher into elongated flat plates that arehard to work and require more cement and sandthan an ideal, blocky-shaped aggregate. Manyof the darker felsites are mistaken for ba­salt, but unlike basalt, this aggregate hasmore deleterious features to watch for.

SOme types of limestone, mainly from thePermian Kaibab Formation (caps the westernhalf of the plateau), contain enough calciumand magnesium carbonates (70%) to be anacceptable aggregate. However, because ofpoor frictional qualities as a consequence ofpolishing, it is not considered desirable touse limestone aggregate in the surface of aroadway. Again, a blend sand is sometimesneeded.

Most sandstones in Arizona, because ofinferior abrasion quali ties, are not used as

an aggregate with asphaltic concrete. SOmesources, however, have been used as a basematerial, and as a subgrade seal.

In some parts of the plateau provincecinders are the only known aggregate availableover large distances. Cinders are used by thebuilding block industry in Arizona for aggre­gate. Ibwever, cinders are not considered asdesirable as other aggregates for road build­ing because of problems with porosity and opengrading. These properties not only causeexcess asphalt to be used, but the percent ofvoids filled varies with the temperature whenmixed, giving mix-design problems. In coolweather the mix has stability but lackscohesion, which would cause cracking of thepavement. In hot weather the mix has cohesionbut lacks stability, which causes rutting inthe pavement. Also, many cinders have a highabrasion value and break down into a plasticmaterial. Cinders, though generally unsuit­able for aggregate, are still used in winterby ADJT to spread on icy roads.

Basin arxl Range Province

This region constitutes the Arizonadesert as most people think of it. Althoughthe annual precipitation indicates an ariddesert, much of the rain comes in a fewviolent storms of short duration causing flashfloods. Moreover, the larger rivers thatcross the province have tributaries that reachinto the higher country along the southernmargin of the CP Province, thus contributingto rapid runoff. While this province is topo­graphically lower than the CP, parts of it arestructurally higher, which causes the oldercrystalline rocks to be exposed. 'The land, ingeneral, is characterized by over one hundredindividual mountain ranges that alternate withbasins filled with materials eroded from thedeveloping mountains. Al though these fault­block mountains vary in rock types and struc­ture, a pattern repeated over and over is asloping surface (piedmont) of varying widthbetween range front and basin center. Theranges, several million years old, have beenwasting throughout their existence. 'The sedi­mentary deposits on the piedmonts constitute acomplex of interbedded lensing materials thatinclude some of the best gravel aggregate inArizona (Figure 1). Coating and cementationof older alluvial deposits (often called"fanglomerates") with clay, caliche (ca C03),or silica, renders the gravels undesirable formost construction purposes. Too, a widevariety of parent materials, both "good" and"bad", have contributed to the gravels fromplace to place. Slates, schists, and gneissesare inferior to quartzites, limestones, andmarbles. Many of the volcanics are of thefelsite group and have the same negativeaspects as they do on the plateau.

117

Figure 1. Aerial view of the Sierra Estrellamountains near Phoenix showing a narrow pied­mont slope at the mountain base. piedmontsare often a source of gravel aggregate. Look­ing southerly.

lOCATION

The main purpose of any prospectingprogram is, of course, locating a deposit.This is done in two steps (a) office review,and (b) initial field review.

Office Review

A comprehensive office review is thefirst step in locating an aggregate source.The initial sources of information are theMaterials Inventory Fblios, maintained by theMaterials Section since 1958. These folioshave four principal parts (1) pit location andair-photo coverage map, (2) geologic informa­tion including a photogeologic map, (3) landstatus map or land ownership map, (4) pit datasheets with test results of material found ateach pit, and past-use record. The base mapused for the folios is a county-map seriespublished by the Photogrammetry and Mappingservices units of ADOT. 'These include drain­age patterns, section, range and townshiplines, and major utilities.

......_---------------_.-

Table 1. Aggregate tests and sampling requirements.

Type of Test Number of Samples Size of Each Sample-----1. Sieve Analysis and P. I. 1 for each stratum of each 25-30 lbs.

test hole

2. Density Minimum of 3 for each pit. 75-100 lbs.

3. pH and Resistivity Minimum of 3 for each pit. 25-30 lbs.

4. Abrasion Minimum of 3 for each pit. 60-75 lbs.

5. Job Mix Minimum of 12 for each job mix. 25-50 lbs.

6. Oversize Minimum of 1 for each job mix. 75-100 lbs.

118

A preliminary list of promising pits iscompiled from the folios, and the informationis updated from our active-pit files and topo­graphic, geolog ic, and land status maps. Inaddi tion, a check is made with Fhotogrammetryand Mapping Services for new aerial photos.After a review of all information, a finallist of potential sites is compiled.

Initial Field Review

The initial field review is made to eval­uate the information developed in the officereview. Existing pit si tes are visited and anattempt is made to determine if these sitescan be enlarged either in depth or in area.Fossible new sites, noted on aerial photos orgeologic maps, are also visited. Preliminarysampling and land-survey-monument location mayalso be done at this time. Unsuitable pitsites are eliminated and sampling is begun onthose remaining. The criteria used for deter­mining the most appropriate sites are dis­cussed under "Preliminary Evaluation".

SAMPLING

Natural deposits of aggregate seldomexist in conveniently graded conditions andwithout overburden. The methoQs of sampling,therefore, are very imPJrtant. Without repre­sentative samples, accurate evaluation of thequality and quantity of aggregate in a depositis impossible.

Sampling Quarry SOurces

In sampling quarry-rock sources, a rotarydrill rig is used to determine depth and areallimits. Useful information can be obtainedfrom observation of the drill cores or cut­tings, the rate of penetration, and the sound.Diamond core, tricone, drag, down hole hammer,and jackhammer bits are used. Both air andwater are available for circulation.

At least one test hole is shot. If thematerial appears suitable, samples are ob­tained for testing and evaluation. The testhole is logged for record and changes noted.

If there is more than one type of materialeach should be represented by a 60 poundsample. The words "Quarry Crush" should appearon all identifying tags. Also, two samples ofeach of the usable strata should be taken andmarked "Fbr Abrasion", with a minimum of threesamples for the entire pit.

An additional sample should be taken ofthe fines generated from the blasting opera­tion and combined with an equal amount offines extracted from seams, fractures, orbedding planes eXPJsed in the test hole. Thissample should be marked "Fbr Information Pur­poses", and will be tested to determine theneed for wasting of natural and shot fines.

Sampling sand and Gravel

For sand and gravel a backhoe is used todetermine depths and areal limits. Although adrill rig is often used for this purpose, abackhoe is considered preferable because thematerial can be observed in place. In addi­tion, it is nearly imPJssible to obtain repre­sentative samples of sand and gravel depositswi th a drill rig. Unless uniformity of mate­rial allows fewer holes tests are spaced 100feet apart. A summary of the size and numberof samples required is listed in Table I.Immediately after the test hole has been exca­vated and is ascertained to be safe for entry,the field man proceeds with a prescribedsampling procedure.

sampling ~ersize Aggregate

The percentage of materials retained onthe 3-inch and 6-inch sieves in aggregate pitsis important because, from a cost point ofview, it indicates the amount of crushingrequired; it determines too ultimate coeffi­cient assigned to aggregate in the pavement­design procedure, and it influences the job­mix formula in asphaltic concrete-mix designs.Fbr these reasons, it is important to make aneffort to determine as closely as possible theamount of oversize rock. The steps involvedinclude selection of holes to be sampled,sampling, and weighing.

q

PRELIMINARY EVALUATION

D..1ring or after the sampling process, andbefore the holes are backf illed, a ma terialsengineer or geologist reviews the proposed pitand decides if the quality of the material ishigh enough to use as aggregate alone, or asan asphaltic concrete aggregate. Other fac­tors considered are quantity, quality, unifor­mity, geologic origin, and numerous develop­ment questions. r:evelopnent questions includeflooding, position relative to water table,response to erosion, zoning or governmentalregulations, slope stability, vegetativeremoval, road requirements, haulage require­ments, and environmental parameters. Thelatter, in turn, include visibility, noise,surface drainage, land-use effect, flora andfauna, blasting effects, etc. If, after con­sidering these factors a pit appears suitable,then the material samples are sent to thelaboratory.

IABORAIDRY TESTING AND FINAL EVALUATION

The principal aggregate tests includegradation (sieving), hydrometer testing forsizing material below 200 mesh, ph and resis­tivity test for corrosive or reactive salts,abrasion, compressive strength of concretespecimens, and petrographic analysis. Thelatter is useful in evaluating various qualityaspects of rocks proposed for aggregate use(Figure 2).

Additional tests are run when the routineaggregate testing indicates that the qualitymay be high enough for use in asphaltic con­crete. Many of these tests are run on theanticipated mixture of aggregate and asphalt.These include stability under traffic, immer­sion compression (reaction to water), voidsanalysis (porosity), cohesion (tested undertension), absorption, specific gravity, etc.

CONCWSION

In order for the design engineer to have adependable basis for making final plans andspecifications, the process of locating, sam­pling, and evaluating potential aggregatesources must be carried out early in a highwayproject investigation. Solving the problemswill invoke the skills and methods of variouspeople. Such work involves the close coopera­tion of a team of geologists, material engi-

119

Figure 2. A microscopic view of a fresh,durable basaltic volcanic rock suitable formaking crushed aggregate. Crystals are ran­domly oriented plagioclase feldspar in a fine­textured matrix.

neers, and field and laboratory technicians.Sources of quality aggregates are beingdepleted in many areas. ZOning, right-of-way,environmental and other considerations arereducing or eliminating many existing andpotential sources. Consequently, it is becom­ing increasingly difficult to develop newsites. This often necessitates the use ofaggregates having marginal quality. Theability to establish criteria for accepting orrejecting such materials, which usually haveno known service record, cannot be overempha­sized •

Solar Salt in Arizona

Jerry Grott811 E. Riley Dr. - suite 55

Avondale, AZ 85323

,"",.c,o,

Eaton and others (1972) named the saltmass the Luke salt Ibdy and generated a multi­ple-hypothesis approach to its origin.Petroleum geologists, always on the alert fornew frontiers, were intrigued by a diapirism­doming model and the related implications.Peirce (1974, 1976) refers to the mass as theLuke Salt and suggests that it, though slight­ly deformed, was deposited in a paleobasinduring Miocene time.

A production company, SJuthwest salt, wasformed. It demonstrated too feasibility of asolar-salt project that could produce an ex­ceptional grade of salt. A contract was madewith California Liquid Gas Company in whichcal-<?as developed storage caverns on a portionof SJuthwest salt's leased property and SJuth-

Figure 1. Map of portion of Bouguer gravitymap showing location of the sal t works withrespect to the gravity-negative center of theLuke Basin. From Peterson, D. L., 1968, u.s.Geological SUrvey map GP-615.

minor interbeds of insolubles (shales, etc.)were cut. It is this section that is beingexploited for salt by solution mining and inwhich subsurface storage cavities were engi­neered by an adjoining operation.

120

SJuthwest Salt Company is solution miningthe Luke Salt Body of probable late Mioceneage. '!he discovery hole, from which too firstcore was recovered, was drilled in 1968. '!hedeposit was encountered at a depth of 880feet, and the bit was still in salt at thebottom-hole depth of 4,500 feet.

The solar ponds, developed on land for­merly dedicated to agriculture, have an annualcapacity of about 90,000 tons. Because landvalues are very high, mining rates and proce­dures are governed by the need for near-satu­rated brine to minimize land requirements.

Because of the frequency of dust storms,the salt operation uses a unique wet-harvest­ing method. Most inventory is kept in theponds under brine and harvested only a fewdays before shipIllent. Studies of the natureof crystal growth and the distribution ofwindblown and brine impurities led to thedevelopment of procedures for processing saltof high chemical purity and low insolublescontent. Chemical purity exceeds that of mostsalt produced in fuel-fired evaporators.

Salt is shipped from Phoenix as far eastas west Texas and as far west as centralCalifornia. OCcasional shipments have beenmade to Hawaii and Alaska.

DISCOVERY-GEOLCGY-PRODUCTICN

My interest in developing a salt industryin Arizona was first stimulated by Dr. H.Wesley Peirce of the Arizona Q:lological SUr­vey. After reviewing all acquired informa­tion, I made arrangements to drill an explora­tion hole in the bull's-eye of a gravity lowin sec. 2, T. 2 N., R. 1 W., Maricopa County(Figure 1). In November 1968, the explora­tion-drilling venture entered solid rock saltat a depth of 880 feet beneath a cotton field.Available funds supported additional drillingto 2,800 feet, still in salt. At this time ElPaso Natural <?as Company, which was interestedin establishing a subsurface natural-gas stor­age facility in western Arizona, was contactedand told of this geologic development. Thecompany immediately supported both the deepen­ing and eventual logging of the hole. Thehole was finally terminated at a depth of4,503 feet (3,400 feet below sea level), stillin salt! More than 3,600 feet of halite, with

ABSTRACT

..west used the brine. Southwest Salt has itsown brine wells independent of the adj acentliquid petroleum gas (LPG-butane, propane)storage caverns project.

A search for a precedent operation in astrict desert environment found none thatproduced salt low in insolubles. Desertstorms load the solar ponds with debris and inoperations such as this, sand and dust areusually not removed. Although winds carrydirt almost daily in the Phoenix area, duststorms occur primarily during July and Augustand occasionally during April and November.Such storms often deposit enough material tocover the salt completely. Studies showedthat the ponds annually collected between 1/8and 1/4 inch of windblown dirt. Because thetotal salt crop averaged 12 inches per year, 1to 2 percent of annual production consisted ofdirt •

. Equipment was developed to harvest thesalt without draining the ponds. '!his allowsharvesting at intervals regulated to minimizeentrapment of dirt in the salt crystals. Italso eliminates the difficulty that a duststorm might cause to a drained pond, in whichdust could dry on the salt and make separationvery difficult. '!he final-harvest flowsheetfeatures one man operating a wheeled dredgepulled by a crawler tractor, which in turn isdriven by an electric-motor hydraulic system(Figure 2). Power is supplied by a trailingmine cable encased in a high-density polyeth­ylene pipe with floats as necessary.

'!he dredge pipeline is also made of high­density polyethylene. This line carries abrine-salt slurry to a wash plant where dewa­tering, screening, and screw-type washingequipment separates salt from brine. Afterbeing washed, the salt is stockpiled by stack­ing conveyor (Figure 3). Only the wheeleddredge and crawler is custom-built. '!he sepa­ration and washing plant is an assembly ofstandard equiflllent that removes almost all ofthe windblown dust and dirt.

Insolubles typically range from 0.01 to0.02 percent (100 to 200 parts-per-million).In one full production test to determine theultimate performance capabilities, insolubleswere reduced to 40 PJ;Jll, calcium plus magnesiumto 12 ppm, and soluble impurities to less than100 pJ;Jll.

Although the plant has not been built toFDA specifications, the salt is considerablypurer than most salt produced in vacuum panevaporators for use in foods. '!he low calciumcontent is useful in curing sausage and insimilar applications in which phosphates areused instead of nitrates. Calcium ties upphosphates and changes the taste of curedfoods.

Cbntracts are routinely made for produc­tion of salt with the calcium-pIus-magnesiumcontent at 35 ppm typically and 50 ppm maxi­mum. At this degree and purity, a sales price

121

Figure 2. Photograph of sal t-harvesting de­vice in brine covered salt evaporation pond.

Figure 3. Photograph of wash plant, stackingconveyor, and stock pile.

can be assigned that is high enough to covershipment costs to destinations such as SanAntonio, Texas and sacramento, california.

'!his Arizona operation has introduced newtechnology to one of the oldest process indus­tries. The substi tution of solar energy forthe four million BTU/ton used in vacuum-panevaporators comes at an appropriate time.salt operators from several foreign countrieshave visited the operation, seeking new tech­nology. '!he harvesting method is adaptable toany size of operation for which slurry pumpsare made. '!his method, plus the one-man oper­ation, allows low entry investment and lowoperating costs that make small-tonnage oper­ations competitive with customary megatonoperations.

'!his new method of producing high-qualitysalt at costs competitive with larger opera­tions serves to decentralize the salt industrywhere the climate allows solar ponds and asalt source is available. SOlar-salt produc­tion is important to developing countries

where markets are smaller, transportation isless available, and energy costs are higherthan in the industrialized nations.

REFERENCES

Eaton, G. P., Peterson, D. L., and Schumann,H. H., 1972, Geophysical, geohydrological,and geochemical reconnaissance of the IllkeSalt Body, central Arizona: u.S. Geolog­ical survey Professional Paper 753, 28 p.

Peirce, H. W., 1974, Thick evaporites in theBasin and Range Province, Arizona, inCoogan, A. H., ed., Fourth symposium onsalt: Northern Ohio Geological society,p. 47-55.

---"7"""":: 1976, Tectonic significance of Basinand Range thick evaporite deposits, inwilt, J. C., and Jenney, J. P., ed5:";Tectonic digest: Arizona Geological soci­ety Digest, v. 10, p. 325-339.

122

Bentonite and Specialty Sand Depositsin the Bidahochi formation, Apache Count~ Arizona

Ted H. Eyde and Dan T. EydeGSA Resources Inc.

P.O. Box 16509Cortaro, AZ 85230

ABSTRACT IN'IRODUCTION

1

Specialty sand and bentonite are producedin the plateau province from the BidahochiFormation near Sanders, Apache County,Arizona. It appears that deposits of bothsand and bentonite formed during the Pliocenein fluvial and lacustrine environments,respectively, along the west side of the r:efi­ance Uplift.

The bentoni te is an alteration product ofairborne vi tric ash that fell or was washed'into lakes. In the Cheto district, the indi­vidual bentonite horizons, which range fromless than a foot to more than 10 feet thick,are restricted to the position of the medialvolcanic member. Bentonite production beganat the Allentown mine in 1924 and the Chambersmine in 1926. In 1933 strip mining of theextensive deposits in the Cheto district co~

menced. Production increased each year to apeak oiE 270,000 tons in 1957. As a result ofthe introduction of synthetic zeolites intopetroleum refining, production declined.About 40,000 tons of bentonite are currentlyproduced from the district each year. Benton­ite is shipped out of State for processinginto desiccants, thickeners, and acid-acti­vated clay products.

The specialty sand was derived fromPermian sandstones and deposi ted by streamsdraining the r:efiance t.plift. Although streamchannels are usually restricted to the uppermember of the Bidahochi, stratigraphicallyabove the bentonite horizon, a few actuallycut through the bentonite. The well-sortedsand, suitable for use as a proppant in hy­draulically fractured oil and gas wells, islocalized in elongate lenses along the marginsof the channels. These lenses range from 5 to50 feet in thickness and often extend thou­sands of feet in both width and length. Thesand is about 97 percent silica, has a yieldof 40 percent in the minus 20 plus 40 meshsize fraction, and has a roundness of 0.6 to0.7 on the Krumbein scale. Production of thissand began about 1961. All of the currentproduction, which amounts to about 40,000 tonsper year, is sold in the petroleum-producingarea near Farmington, ~w Mexico.

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Specialty sand and bentonite are producedin the plateau province from the BidahochiFbrmation near sanders, Apache County, Arizona(Figure 1). Bentoni te from the Bidahochi

Figure 1. Map of Arizona showing location ofCheto bentonite and sand deposits.

Formation was used in the original crackingcatalysts at oil refineries. This applicationwas quickly displaced, however, when syntheticzeolites with their smaller cavities and supe­rior properties became commercially available.Bentonite is currently used in acid-activatedand desiccant applications.

The crude bentoni tes now being mined areprocessed at plants in ~w Mexico, California,and Mississippi. The products and their per­pound values include high value-added desic-

cants ($0.36 - $0.50), acid-activated benton­i tes ($0.10 - $0.20), and thickeners and gel­lants (more than $1.00).

The Cheto bentonite deposits in theBidahochi Formation formed during the pliocenein a series of interconnected lakes on thewest side of the D3fiance uplift. '!he benton­ite is the alteration product of vitric ashdeposi ted in the lakes in at least two hori­zons. '!hese horizons now range from less thana foot to more than 13 feet in thickness. '!hebentoni te is a remarkably pure dioctahedralcalcium montmorillonite member of the smectitegroup of clay minerals. It is the nearlymonomineralic composition, a high crystallin­ity, and the large surface area that producethe extraordinary sorptive properties.

'!he most serious problem facing the opera­tors in the district is the increasing over­burden thickness, which now averages nearly100 feet. In certain areas, a thick bed ofhydrofrac sand occurs in the overburden andmay offer opportunities to produce an addi­tional salable product, thus reducing overallstripping costs.

Proppant sand production from the uppermember of the Bidahochi Formation began in1961 from deposits in the Houck area, NavajoIndian Reservation. '!hough sand is a mineralresource believed to occur almost everywhere,deposits of sand sui table for use as a prop­pant in hydraulically fractured oil and gaswells are uncommon. neposi ts of these spe­cialty sands were derived from uplifted andreworked R:lrmian sandstones and deposited in afluvial environment near the southwest part ofthe ·D3fiance Uplift.

The hydrofrac-sand products are the minus10 plus 20 and the minus 20 plUS 40 meshfractions. '!he products are about 97 percentsilica, have a roundness of 0.6 to 0.7 on theKrumbein scale, and have a low acid solubil­ity. oil-well service companies have beenusing about 80,000 to 100,000 tons per year tocomplete oil and gas wells in the Farmington,New Mexico area. The Arizona Silica SandCompany has been supplying about 40 to 50percent of this market.

Hydrofrac sand is a high value-added spe­cialty sand product that sells for more than$25 per ton foOb. the plant. Production fromthe Arizona Silica Sand deposit at Houck isrestricted because homes have been constructedon the westward extension of the deposit.Nearly identical deposits of sand overlieparts of the nearby Cheto bentonite depositjust off the Navajo Reservation.

Both Filtrol aorporation and united catal­ysts Incorporated operate surface bentonitemines in the Cheto bentonite district. TheFiltrol operation is now stripping about 90feet of overburden to mine about 25,000 tonsof bentonite per year. United Catalystsstrips 85 feet of overburden to mine about12,000 tons of bentonite per year. At both

124

mines, the bentonite bed averages 5 feet inthickness.

Bentonite from the Filtrol mine is shippedto Jackson, Mississippi for processing intobleaching clays used as desiccants and toclarify edible oils. In the past, virtuallyall of the bentonite from the United catalystmine was sold to Culligan USA for processinginto desiccants at their plant in san Bernar­dino, California. In october 1983, UnitedCatalysts opened its processing plant atBelen, New Mexico, about 50 miles south ofAlbuquerque. At that time, Culligan was noti­fied that United catalysts would supply onlyprocessed bentonite. As a result, Culligan isnow purchasing crude bentonite from a somewhatlower quality deposit in SOnora, Mexico.

location and Land Status

The more recent drilling data are fromArizona State Mineral Leases controlled byEngelhard aorporation in sec. 16 and 36, T. 21N., R. 29 E., Apache county, Arizona. Whenthe State of Arizona issued the mineral leasesto Engelhard COrporation, the surface andmineral estate of these sections belonged tothe State. In 1985, however, surface rightswere transferred to the Bureau of Land Manage­ment (BLM) to hold in trust for the NavajoTribe as part of the Navajo and Hopi IndianRelocation Amendment Act of 1980. The BLMalso acquired the Wallace and Ibberts ranches,which owned surface rights to sections sur­rounding State sections 16 and 36. The min­eral estate of these lands was not acquired.'!he santa Fe Railroad aompany, which owns themineral estate under 140,000 of the 250,000acres being acquired by the BLM for the NavajoIndians, has filed a ~200-million lawsuitrequesting compensation for their mineralproperties. Because of the transfer of sur­face rights to the Navajo Tribe, Santa Febelieves that access to any fuel- or nonfuel­mineral deposits discovered on the split­estate lands may be denied by the Tribe. TheState of Arizona retained the mineral estateon sections 16 and 36. It is the State'sposition that the leases the State issued onthese lands remain in full force and effect.An agreement, however, must be negotiated withthe Navajo Tribe to ensure unrestricted accessto the Indian lands.

It is still unknown when or if the BLMwill transfer ti tIe of the surface estate ofthese trust lands to the Navajo Tribe. Re­portedly, the Navajos must take possession ofthese lands by July 1986. Complicating thistransition is a lawsuit filed by the NavajoTribe to block implementation of the Joint UseRelocation .Act. '!his could result in the BLMretaining the lands now held in trust for theNavajos. If this were to happen, the landwould probably be managed under multiple-useguidelines. In any case, this is an example

------------------~~

of an important and valuable natural resourcepotentially made worthless by a poorly Con­ceived and implemented Federal program.

GEOLOGY

Kiersch and Keller (1955), while investi­gatirq the mineral rerource potential of theNavajo Indian Reservation, described the geo­logy of the nearby Cheto clay deposits indetail. '!heir work is summarized and upjatedby exploration drilling completed between 1978and 1983.

The bentonite deposits originated from thealteration of a vitric ash approximatingquartz latite in composition. D3posi tion wasapproximately contemporaneous with that of themedial or volcanic member of the BidahochiEbrmation. Bentonite deposits occur in chan­nels and basins above the lower member and mayextend a few feet into the upper member. Theclay outline does not conform to the ash con­tact in all places. '!hese depositional trapscontain most, if not all, of the known benton­ite deposits. Although related rhyolitic tobasaltic ash beds are common elsewhere in theBidahochi, the particular environment of thisarea and the latitic composition of the vitricash seem to have controlled the alteration tobentonite.

'!he bentonite is invariably overlain, andin some cases underlain, by reddish or tansilt. !:'brmally both the upper and lower con­tacts with silt are sharp. Where the silt isadmixed with clay, however, usually near themargins of basins and channels, the sand con­tent of the clay may increase to 4 to 6 per­cent, a prohibitive concentration for commer­cial use.

The bleaching-clay deposits predate thefirst coarse sand lenses or lenticular beds ofthe upper member of the Bidahochi Ebrmation.Deposits of bentonite rarely occur directlybeneath an outcrop of these sands or immedi­ately adjacent to sand pinchouts. Instead,high-puri ty bentonite deposits occur at somedistance from pinchouts and at stratigraph­ically lower horizons within siltier strata.

Although high-grade bentonite depositsaverage from 3 to 5 feet in thickness, a 13­foot bed was sampled in drill holes southeastof the Cheto pi ts. This variation in thick­ness may be due to an undulatirq depositionalfloor, irregular erosion of the deposit, orlateral position in the deposit with respectto its marg ins.

The Bidahochi Formation was depositedprimarily on an irregularly eroded surface ofolder rocks. '!he pre-Bidahochi surface, simi­lar to that which exists today, consisted ofstream channels, lake basins, and other sur­face irregularities. Volcanic ash falls oc­curred during medial Bidahochi time and cov­ered most of the landscape. The latitic ashfilled stream channels and depressions. It

125

appears that a considerable part of the ashwas vitric and that this material was furtherconcentrated in permanent streams, smalllakes, and ponds by current flow. The sourceof the ash is speculative, but several possi­ble volcanic centers were active near theboundary of the Bidahochi basin. The lakescontained fresh water that had a greater con­centration of calcium and magnesium than sodi­um, the bentonite being a calcium montmoril­lonite.

Between 1978 and 1983, 37 rotary-coreholes were drilled to explore the bentonitedeposit in sec. 36, T. 21 N., R. 29 E. in theTolopai Spring 7.5- minute quadrangle.Thirty-six of these intersected bentonite.This widely spaced drilling program definedthe size of the bentonite deposit and theoverburden depth. In 1981 the explorationdrilling discovered a second bentonite bedabout 30 feet below the main bed. Analyticalresul ts showed that both the upper and lowerbeds were similar mineralogically and could beused to make desiccants that meet militaryspecifications. '!his lower horizon has yet tobe exploited. Earlier drilling in nearbysection 16 intersected a deposit of hydrofracsand overlying the bentonite. Cuttirqs fromthe drill holes in section 36 were thereforeroutinely logged for sand attributes.

Based on the samplirq and analytical work,a hydrofrac-sand deposit overlying the benton­ite was identified in the northeast quarter ofsection 36. The potential yield is higherthan that from other deposits, incltdirq thosemined by Arizona silica Sand Company on theNavajo Indian Reservation. Between 1983 and1985 sand from section 16, off the reserva­tion, supplemented the feed to the company'splant in Houck. Tests by Arizona TestingL:iboratories in phoenix am Core L:iboratories,Inc. in Corpus Christi, Texas, determined thatthe roundness and sphericity, size distribu­tion, and composition equaled or exceeded thatof the hydraulic-fracturing sand produced byTexas Mining Company and Pennsylvania GlassSand Company from the Brady deposit at Voca,Texas.

Hydraulic-fracturing sands are used asproppants after a well is hydraUlically frac­tured to stimulate oil and gas production.Arizona Silica Sand Company's production of40,000 tons per year supplies about 40 percentof the hydraulic-fracturing sands consumed byoil and gas wells in the Farmirqton, New Mex­ico area. The sand product sells for $25 to$28 per ton Lo.b. the plant at Houck,Arizona.

PROIXJCTION AND MARKETS

calcium Bentonite

Bentonite production began in 1924 when 30tons of nonswelling calcium montmorillonite

was shipped from the Allentown mine. FiltrolCorporation contracted for the production fromthe Chambers underground mine in 1926. Dlringthe 1930's, both the Filtrol Corporation ex­ploration department and C. A. Mccarrell beganexploration programs to locate other bentonitedeposits in the district. As a result ofthese efforts, the Cheto mine, a surface oper­ation, began production in 1933.

'!he underground operation at the Chambersmine closed in 1938, leaving the Cheto surfacemine as the only producer in the district.111e Cheto mine yielded 11,616 tons of benton­ite during its first year of operation. Pro­duction increased to 144,000 tons in 1949,250,000 tons in 1954, and a peak of 270,000tons in 1957. Production then steadilydeclined for many years. In 1961 productionwas 50,000 tons, and according to the ArizonaD3partment of Mineral Resources, production in1975 reached a low of about 20,000 tons fromthe Filtrol mine. The other operation in thedistrict, the Glrley bentonite mines, producedabout 5,000 tons during 1975. District pro­duction since 1975 has doubled to about 40,000tons per year. All of the clay produced isused in high value-added markets includingclay desiccants, specialty clay gellants, andacid-activated bentonites. These productssell for $0.10 - 2.00 per pound. The largestproducer in the district is the Harshaw­Filtrol partnership, which is managed by Kai­ser Aluminum and Chemical Corporation. Cur­rently 25,000 to 30,000 tons of calcium mont­morillonite are mined from the Harshaw-Filtrolproperties and shipped to Jackson, Mississippiby rail for processing into desiccants andacid-activated clay. '!he Jackson, Mississippiacid-activation plant has a reported capacityof 80,000 tons per year of product. Up to20,000 tons of Cheto clay are blended withMississippi and louisiana calci um bentoni testo produce several grades of acid-activatedclay products, which sell for $300 to $400 perton and are sold under the Fil trol tradenames. Harshaw-Filtrol is also a major produ­cer of clay desiccants. Filtrol annually usedas many as 10,000 tons of Cheto bentonite inthis application. In July 1984, Filtrol an­nounced that the clay-products plant inJackson, Mississippi would double itsdesiccant-production capac i ty.

The other major producer at the Chetobentonite deposit is United D3siccant Corpora­tion, a subsidiary of Sud-Chemie AG, a major.West German clay company. United D3siccantcontrols a bentonite resource at Cheto esti­mated at about 1.5 million tons. The canpanypurchased the reserve from C. E. Gurley for areported $3.5 million in 1980. '!he clay fromthis operation is shipped by truck to Belen,~w Mexico for processing into desiccants andto louisville, Kentucky for processing intospecialty clay gellants sold under the Tixogeltrade name. Originally, United D3siccants

126

sold crude clay to CUlligan Corporation forprocessing into desiccants. But on completionof the Belen plant, only processed clays weresold.

Acid-activated clays are calcium mont­morillonites that have been treated with acidto improve their physical properties. Thechemical and physical properties of the finalproduct are dependent on the source clays, thefeed-clay particle size, and the specificactivation process used. In the United Statesand Canada, the Harshaw-Filtrol partnershipdominates the industry with an estimated100,000 tons per year of capacity, or nearly20 percent of the world total. AmericanColloid Corporation has entered the u.s. mar­ket with a plant in Aberdeen, Mississippi andbegan production in NJvember 1985. 111e capa­city of this operation is reported to be12,000 tons per year.

Producing clay desiccants adds value tothe clay through packaging rather than pro­cessing•. 111e processing is relatively simple.The crude clay is dried, crushed to minus 3mesh, and heated to remove the water. Oncethe clay has been activated, it must be pack­aged. The packaging process puts a measuredportion of clay into permeable paper or othercontainers, ranging in size from 1 gram tomore than a kilogram, which readily allowswater to be absorbed by the desiccant.

In summary, 40,000 tons per year of claymined at the Cheto bentonite deposit generateor contribute to products that have totalrevenues estimated at $42 million per year.No other deposit presently in production inthe United States can match the unique physi­cal and chemical properties of the Cheto ben­tonite.

Proppant sands

Hydraulic-fracturing sand is a specialtysand used by oil-field service companies as apropping agent in the stimulation of both oldand newly completed oil or gas wells. When awell is treated, fractures in the producingstrata are opened by pumping a sand-bearingfluid down the well bore and into the reser­voir under extremely high pressures. When thepressure is released, the sand grains prop thefractures open so that- the oil and gas canflow more freely into the well.

Because of the high compressive pressuresand corrosive environment in oil wells, hy­draulic-fracturing sands must meet rigid phys­ical and chemical specifications. The sandmust have a high SiO~ content, preferablyabove 97 percent. The Individual sand grainsshould be well rounded to allow free movementof the sands into the fractures. Contami­nants, such as calcite or feldspar, are unde­sirable.

Grain size is especially important. Theoil field service canpanies, such as Hallibur-

•

ton and Dowell prefer the minus 20 plus 40mesh size, although sometimes a coarser sand,minus 10 plus 20 mesh, is used. When evalu­ating sands in Texas, Oglebay Norton deter­mined that the deposits must have at least 40percent plus 40 mesh and 25 to 30 percentminus 20 plus 40 mesh to be economic. Lesseramounts of coarse sand and finer sand aretolerated because they can be sold for filter,blast, and foundry sand. About 50 percent ofthe total crude sand mined is screened andwashed; the remainder returns to the pits astailings.

The sand or sandstone deposits must beamenable to open-pit mining. In Texas,Oglebay Norton (Texas Mining Company) andPennsylvania Glass Sand Cbmpany mine a friablesandstone that has to be drilled and blasted.This sandstone is so friable that little wearis produced on the crusher jaws. The sandgrains are cemented by a thin clay coatingthat washes off easily in the wash plant. AtCheto, the sand is unconsolidated and is minedwith a front-end loader. All of the sandsmust be washed, screened, and dried.

There are very few sand or sandstone depo­sits in the United states capable of producingproppant sand. ottawa Silica produces frac­turing sands from the st. Peter Sandstone inIllinois, plus an array of other silica prod­ucts. Oglebay Norton and Pennsylvania GlassSand Company produce from the lower HickorySandstone of Upper Cambrian age in centralTexas. This is the only formation known tocontain fracturing-sand deposits in Texas.Arizona Silica sand produces from a deposit atH:>uck. sand deposits near Fbuntain, Coloradoproduce a poor-quality fracturing sand.

The use of sand as a proppant in thehydraulic fracturing of hydrocarbon producingformations began in 1949. The markets forhydrofrac sand grew rapidly through the 1970' sat 10 to 20 percent annually, along with therapidly increasing oil and natural gas prices.In 1980-81, the growth in consumption slowedwith the decline in energy prices. Consump­tion remained stable at between 1.5 and 1.8million tons annually through 1983. Fallingoil prices appear to have stimulated the mar­kets for proppant sands in 1984 and 1985 as aresul t of the increased emphasis on shallow,low-cost production wells. Based on prelim­inary data from the u. S. Bureau of Mines,

127

consumption of proppant sands totaled 2 to 2.1million tons in 1985. The price of this ma­terial ranges from $22 to $28 per ton f.o.b.the Arizona plant.

The proppant-sand deposits at Cheto arethe westernmost in the United States. ArizonaSilica Sand supplies about 40 percent of thehydraulic-fracturing sand used in the oilfields near Farmington, New Mexico. ArizonaSilica Sand's closest competitors are TexasMining Company, a subsidiary of OglebayIDrton, and Pennsylvania Glass Sand Company,now a subsidiary of U.S. Borax. Both producehydraulic-fracturing sands from a deposit nearBrady, 'Iexas. The Arizona Silica sand Companyproduct enjoys a significant price advantageover the Texas producers, based on freightrates. Furthermore, because Arizona Silicasand Company mines an unconsolidated sand inan arid area, it does not have to blast orpump water from the pit, as do both of theTexas producers. As a result, its miningcosts are lower.

FUTURE

Known geologic reserves of bentoni te inthe Cheto district are under lease. At thepresent rate of removal, these reserves seemadequate for the forseeable future. Less isknown about the overall distribution ofreserves of specialty sand. Much of the re­maining resource potential, however, appearsto be spacially similar to the clay distribu­tion. Although the geologic factors appearfavorable, pending political factors cloud thefuture of these relatively scarce nonmetallicmaterials.

REFERENCES

Clark, G. M., 1985, Special clays: IndustrialMinerals Magazine, v. 216, p. 25-51.

Dickson, E. M., 1984, North America silicasand: Industrial Minerals Magazine, v.197, p. 39-45.

Kiersch, G. A., and Keller W. D., 1955,Bleaching clay deposi ts, in Mineral re­sources, Navajo-Hopi Indian-Reservations,Arizona-utah, v. 2, nonmetallic minerals,geology, evaluation, and uses: universityof Arizona Press, 105 p.

Mexico's Industrial Minerals

Joaquin RuizIEpartment of Geosciences and

Edmundo BerlangaIEpartment of Mineral Economics

University of Arizona'Dlcson, 'NZ 85721

Alth)lIJh Mexico is known for its imrortantbase-and precious-metal derosits, and latelyoil, some industrial minerals play an imror­tant role in the Mexican economy. SUlfur, themost imrortant industrial mineral produced,accounts for approximately 7.5 percent of thetotal value of mineral production. This com­modity is followed by fluorspar, whichacoounts for 6.4 percent. Predominantly, thefluorspar deposits are very high grade (75percent CaF) and are oontained in lower creta­ceous limestone in the states of Cbahuila andSan Luis Potosi. Base-metal derosits in thearea of Parral (notably San Francisco delOro), however, have become imrortant fluoriteprodocers in their own right. (San Franciscodel oro has 12 percent fluorite gangue.) Saltfrom the Guerrero Negro solar-evaporation

ronds in Baja California acoount for 6 percentof the total shares: phosphate from Baj aCalifornia also accounts for 6 percent.Barite from manto derosits in rower cretaceouslimestone in Cbahuila and exhalative derositsin the Paleozoic section of SJnora account for1.0 percent. In addition, Mexico is an imror­tant producer of gypsum, graphite, andcelesti te. Although graphi te and celesti teare not large-scale operations and thus do notcontribute much to the Mexican economy, theMexican graphite and celestite derosits areamong the most imrortant in the world: Mexicois one of the world's few sources ofcelestite. The celestite is in the form oflarge, high-grade mantas in cretaceous lime­stones in northern Mexioo.

128

Approach to Locating High-Quality Aggregatesin the Basin - Range Province

James R. Miller, G. Ramanjaneya,and Gerald Allen

The Earth Technology Corporation3777 Ion;] Beach Blvd.

Ion;] Beach, CA 90807

Recent experience over extensive areas ofthe Basin and Range Province has demonstratedthe importance of the basin's (valley's) geol­ogy and geomorphology in locating large quan­tities of gocd-quality aggregate.

First, a geologic map depicting basicgeomorphic-geologic tmits in a valley is madein the office from aerial photography. t\Ext,derivative maps are made from geologic mapsand field-derived information such as parentrock type, source area and depositional en­vironment, relationship to adjacent deposits,and Quaternary geologic history.

Studying the derivative maps leads toselection of test sites for potential depositsof high-quality aggregates. Subsequent fieldstudies provide more detailed informationabout geolog ic processes and samples forlaboratory testin;]. Combinin;] all informationallows the characterization of aggregate

129

potential of very large areas. Favorableareas can be further tested. This phasedapproach has proven to be cost effective.

The methodology used in mapping and char­acterizing basinfill deposits is applicableover much of the western United States. Mapuni ts were developed by focus ing on the pre­dominate geomorphic process, grain size,cementation, and relative age. The resultin;]functional map uni ts are of use to eng ineersand planners.

This study led to many conclusions, in­clu::Hng the fact that the best quality basin­fill aggregates are fotmd in selected alluvialfan deposits and Pleistocene lakeshore depo­sits. The best quality aggregates are derivedfrom Paleoroic carbonate and quartzitic parentmaterials that can also provide high-qualitycrushed-rock aggregates.

Geologic Evaluation of the Southern Portionof the Searles Lakel California

Brine-Saturated Evaporite Deposits: An Update

K. N. santiniFbnnerly with

Anaconda Minerals ObmpanyD,mver, CO 80202

The evaporite deposit at Searles Lakeconsists of alternating brine-saturated salinebeds and saline-bearing mm beds. '!hree majorsubsurface brine-saturated saline horizonshave been identified by private companies andthe U.S. Geolog ical Survey. They have beentermed, from bottom to top, the Mixed Layer,Lower Salt, am Upper Salt.

The important water-soluble components(t:Ja, K, ,Mg, ~03' HC03 , S04' Cl, and 8 4°7) areeIther m brmes or have combined to form thefollowing minerals: halite, hanksite, trona,nahcolite, burkeite, borax, thenardite,northupite, sulfohalite, glaserite, etc.Kerr-McGee Chemical Cbrp., the current opera­tor at the lake, selectively pumps intersti­tial brines from each of the major rnrizons tofeed its three chemical plants. As the ptmp­ing continues, brines are continuouslyreplenished within the deposit by dissolutionof the minerals through natural recharge orartificial fluid injection (solution mining).'!he brines are processed to produce a varietyof chemical products, which include sodiumcarbonate and sulfate, potassium chloride andsulfate, sodium borate, and boric acid.

'!he Anaconda Minerals Cb. has been evalua­ting potential domestic trona acquisitionsince 1981. We have evaluated various proper­ties in the Green River, Wyoming trona dis­trict, and OWens Lake and Searles Lake insouthern California. In 1983, we purchasedwi th our joint-venture partner, Leslie Salt

Cb., the southern portion of searles Lake fromo::cidental Ietroleum Cbrp.

Since mid-1983, Anaconda has been comuct­ing a small exploration-drilling program atthe property. The initial core holes weredrilled along and adjacent to the existingaccess road. In 1984 we used an all-terraindrill rig to gain access to drill sites on theplaya where no roads exist. The use of thisequipment proved to be highly successful.

The drill pregram consists of oaring to anaverage depth of 450 feet and collecting brinesamples from potentially commercial horizons.The brine samples are collected by setting apacker and swabbing the hole. The core islegged and split lengthwise; one-half is sub­mitted to our Tucson Geoanalytical Laboratoryfor semi-quantitative mineralogy by X-raydiffraction and the following suite of chem­ical analyses: Na, K, Mg, C03, HC03, S04' Cl,8 4°7' Ii, H20 insolubles, am acid msolUbles.

Additional test work for selected coresamples will include effective porosity andhorizontal permeability determinations. '!hebrine samples are subjected to the same suiteof chemical analyses (minus insolubles) as thecore samples. In addition, specific gravityis also determined.

, Both cross sections and isopach maps arebeIng constructed. The hydrological charac­teristics of the potentially commercial rnri­zons are also being investigated.

130

-Raw Materials and the Manufacture

of Vitrified Clay Pipe in Arizona

Ibn M:>rrisBuilding Products Company

4850 W. Buckeye R:1.Phoenix, AZ 85043

The Building Products Company is Ehoenixbased and owned by Mission Clay products ofCalifornia. Building Products is the onlymanufacturer of vitrified clay pipe inArizona. 'The marketing area incl1..des Arizona,Nevada, Utah, J:\ew Mexico, am California.

Building Products, promoted by ArizonaPublic Service, was formed in 1970. Raw­materials prospecting was undertaken for 2years, after which a $5-million plant wasbuilt. Initially, a satisfactory vitrifiedproduct could not be made with the rawmaterials then in hand. Subsequent prospec­ting and testing led to an acceptable raw­materials mix. Testing to upgrade the finalproduct is a continuing process.

The basic raw-materials supply must beadequate, secure, and capable of sustainingclose tolerances in the final product. 'Theseneeds are met by mining four geologicmaterials at three different localities: (1)refractory aluminous shales (two horizons-onepi t) Cblorado Plateau Province (Mogollon Rim) i(2) less refractory aluminous materials fromlate cenozoic lacustrine materials near reweyin the Transition Zone (TZ)i and (3) Precam­brian "slate" from near New River along therouthern edge of the TZ.

other additives include grog (ground-Up,

broken pipe) and barium carbonate that ties upwhat gypsum there is. Calcium magnesiumcarbonates are deleterious ccmponents that areminimized by careful selection of the minedproducts.

The raw materials are blended and mixed,ground to 12 mesh, mixed in a pug mill,depleted of air, extruded into pipe rangingfrom 6 inches to 42 inches in diameter,transported to a hot-air drying room, fork­lifted to an appropriate kiln, and fired at a1900-20000 F range.

The "Rim" kaolinitic shales, being themost refractory ingredient, stabilize the pipeduring the firing process. They are veryplastic, and therefore facilitate extrusion.'The rewey clay fuses at a low temperature andfonns an impervious glasslike binder. It alsois plastic. 'The "slate" forms platy particlesthat tend to orient themselves during laminarflow. This provides strength for both thegreen and dried product. It doesn't absorbwater, which helps the drying process. Grogremains stable during firing, and thereforehelps to control shrinkage.

The development of appropriate rawmaterials and proper mixtures has been doneEmpirically.

Vitrified clay pipe in storage at Building Products COmpany facility near Phoenix.

13J

-------------------------------------------~~~~~~~~-----------~-

SOurce of refractory aluminous shales of Cretaceous age on the southern edge of the Colorado

Plateau near pinedale.

Source of less refractory aluminous materials from late Cenozoic lacustrine materials in theTransition Zone near Dewey.

The Bowie Chabazite Deposit

Ted H. Eyde and Dan T. EydeGSA Resources Inc.

1235 E. Mxmridge Ri.Tucson, AZ 85718

The Bowie chabazite deposit has yieldedthe most mined tonnage of any natural zeolitedeposi t in the United states. Since 1962 thedeposit has yielded about 12,000 tons of crudechabazite, with an estimated market value of$30 million when sold as an activated molec­ular -sieve product.

Between 1,000 and 1,500 tons of high­purity crude lump chabazite is now producedannually by stripping and selectively miningthe lower, massive, half-foot-thick, "high­grade" bed. All of the chabazite is stillshipped out of State for grinding prior toextrusion and activation.

Zeolite minerals were discovered at theBowie deposit in 1875, when OScar Lowe ident­ifieda hydrous silicate related to chabaziteor stilbi te from a tuff bed that cropped outin the San Simon Valley. It was not until1959, however, that chabzite, erionite, andclinoptilolite were positively identified asthe principal constituents of an alteredvitric-tuff horizon that crops out in the areaoriginally described by Lowe.

Shortly after the rediscovery of zeoliteminerals in the San Simon Valley, several ofthe major producers of synthetic zeolitesacquired land positions covering the outcrops,including projected extensions, and began

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exploration drilling. By 1980 all of theknown chabazite reserves had been acquired byfive companies and two individuals.

The more than 3, 000 holes drilled to ex­plore the deposit and the excellent exposuresprovided by the strip-mined areas indicatethat the chabazite-bearing horizon (known asthe marker tuff) is confined to a flat-lyinglacustrine section known to the operators asthe Green Lake Beds. The deposi tion of theparent airborne vitric ash and subsequentzeolitic alteration was controlled by manyfactors, inclu:l ing the lake-bottom topography,depth and cation content of the saline­alkaline lake water, and proximity to post­depositional erosion surfaces.

Zeolitic alteration was complete when anextensive system of younger paleochannelsdeeply eroded the Green Lake Beds. '!his leftonly a few erosional remnants of the markertuff and the lower "high-grade-bed" that con­stitute the present deposit. Both the channelgravels and the Green Lake Beds are overlainby a section of halite-bearing brown mud­stones, known as the Brown Lake Beds. TheBowie chabazite deposit can be used as a modelto guide the exploration and development ofother zeolite deposits that fonned in saline­alkaline lacustrine environments.

Arizona Portland Cement CompantsRillito Operations

J. W. PainsCalifornia Portland Cement oampany

P. O. Ibx 947Colton, CA 92324

I)

Arizona Portland Cement Company's lime­stone deposit (called Twin Peaks) is approx­imately 4 miles southeast of the cement plant.The pant is adjacent to both the SO,uthernPacific Railroad and Interstate 10, about 17miles northwest of TUcson.

Placer claims were filed on the Twin Peaksdeposits in 1923. From that time until thepresent, geologic data have been accumulatedand evaluated to define more closely thequantity and quality of the limestones.

The cement plant at Rillito was originallyconstructed as a one-kiln plant in 1949.Capacity was increased in 1952 and 1956,bringing the plant to an annual capacity of44,000 tons of cement. In 1972 another expan­sion program was completed, bringing annualcement capacity to 1.1 million tons.

Geolog ically, the Twin Peaks containformations ran:Jing from the Precambrian pinalSChist to the Pennsylvanian Naco Formation.Within this sequence, other exposed formationsinclude the Cambrian Balsa Quartzite andAbrigo Fbrmation, Devonian Martin Limestone,

Mississippian Escabrosa Limestone, and Penn­sylvanian Naco Fbrmation.

C?enerally, the Escabrosa, Naco, and MartinFbrmation are the primary sources of limestonefor manufacturing cement. '!he Martin Fbrma­tion is basically a dolomite with bands oflimestone, quartzite, and siltstone. Theselimestones are blended with outside sourcematerials (clay and iron ore) to make a rawmix that will make specification cements.

Several drilling programs were initiatedbetween June 1946 and March 1982. Informationderived from these programs provided the meansto develop cross sections, geologic blocks,and grade blocks. The configurations of thegeologic and grade blocks are the same. Blockboundaries delineate the various formations onany particular level.

Cursory inspection of the structure wouldindicate a broad syncline elevated on the westside. A more detailed examination shows thatthe structure has been complicated by severalperiods of faul ting and intrusion of igneousrocks.

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