STRATEGIC MINERALS INVESTIGATIONS 1941 - … STATES DEPARTMENT OF THE INTERIOR Harold L. Ickes,...

UNITED STATES DEPARTMENT OF THE INTERIOR Harold L. Ickes, Secretary

GEOLOGICAL SURVEY W. C. Mendenhall, Director

Bulletin 931

STRATEGIC MINERALS INVESTIGATIONS1941

PART 1, A-J

Short papers and preliminary reports by

EUGENE CALLAGHAN, S. W. HOBBS, L. R. PAGE

and others

UNITED STATES

GOVERNMENT PRINTING OFFICE

WASHINGTON : 1943

r:^ 1̂ HALL LIBRARy

CONTENTS

(The letters in parentheses preceding the titles are those used to designatethe papers for separate publication]

' * Page(A) Tungsten resources of the Blue Wing district, Lemhl

* County, Idaho, by Eugene Callaghan and D; M. Lemmon(published in June 1941)............................ 1

(B) Some quicksilver prospects in adjacent parts of Nev- "^ ada, California, and Oregon, by C. P. Ross (pub- ! lished in June 1941)................................ 23

(C) Tin deposit at Majuba Hill, Pershing County, Nevada, by W. C. Smith and V. P. Gianella (published in March 1942)......................................... 39

^ (D) Nickel-gold deposit near Mount Vernon, Skagit County, Washington, by S. W. Hobbs and W. T. Pecora (pub lished in January 1942)............................. 57

(E) Tungsten deposits in the Sierra Nevada near Bishop, California, a preliminary report, by D. M. Lemmon (published in March 1942)........................... 79

(P) Nickel deposits of Bohemia Basin and vicinity, Yakobi > Island, Alaska, by J. C. Reed and J. V. N. Dorr 2d

(published in May 1942)............................. 105(G) Chroiaite deposits of Kenal Peninsula, Alaska, by P. W.

' Guild (published in March 1942)..................... 139* (H) Tin and tungsten deposits at Silver Hill, Spokane

County, Washington, by L. R. Page (published in Au- , gust 1942)........................................... 177

'' (I) Nickel deposit near Riddle, Douglas County, Oregon, by W. T. .Pecora and S. W. Hobbs (published in March 1942)............................................... 205

(J) Quicksilver deposits in the Steens and Pueblo Moun tains , southern Oregon, by C. P. Ross (published in March 1942)........................................... 227

ILLUSTRATIONS

y - _________

r- PagePlajbe 1. Geologic map of productive part of the Blue Wing

_ district, Lemhi County, Idaho............ In pocket2. Level maps and sections of the Ima mine showing

A. geology................................... In pocket3. Longitudinal projections on vertical plane of

the Ima mine.................................. 204. Composite level map.of the Ima mine........ In pocket5. Maps of prospect tunnels, Ima mine.............. 20

"* "6. Index map of adjacent parts of Nevada, Califor nia, and Oregon, showing the location of the

* properties described.......................... 26

III

IV ILLUSTRATIONS

Page Plate 7. Geologic and topographic map of the principal

part of the Lone Pine district, Washoe County., Nev........................................... 26

8. Topographic sketch map of the Glass Buttes pros pect, Lake County, Oreg....................... 34 *

9. Geologic map and section of Majuba Hill,Nev....................................... In pocket ^

10. Geologic map and sections of the Majuba Hillmine................ *.................... In pocket >

11. Map showing location and geologic setting of theMount Vernon district......................... 60 ^

12. Geologic map and sections of Mount Vernonnickel-gold deposit........................... 60

13. Index map of southern California showing loca-tion of Bishop region and plate 14............ 82

14. Map of parts of the Bishop, Mt. Goddard, and Mt. Morrison quadrangles showing location of tung sten properties 0 ......»..o............... In pocket

15. Geologic map and section of the vicinity of PineCreek mine, Inyo County, Calif........... In pocket

16. Geologic map of the Pine Creek pendant..... In pocket17. Photograph showing the Pine Creek pendant on the t

north side of Pine Creek, Inyo County, Calif.. 9018. Geologic map of level A of the Pine Creek mine.. 9019. Geologic map and sections of the Tungstar mine.. 9820. Geologic and topographic map of Bohemia Basin

and vicinity, Yakobi Island, Alaska.... . In pocket21. Geologic and topographic map of the area sur

rounding the Tripod, Tunnel, Side Hill, and Muskeg sulfide-bearing bodies, Yakobi Islanu, Alaska........................................ 124

22. Geologic and topographic map of the area sur rounding the Takanls sulfide-bearing bodies, n- Yakobi Island, Alaska......................... 124

23. Geologic maps of prospect pits and tunnel in - sulfide-bearing bodies of Bohemia Basin and ^ vicinity, Yakobi Island, Alaska.......... In pocket

24. Geologic reconnaissance map of the southwesternpart of Kenai Peninsula, Alaska............... 142 >.

25. Geologic map of Claim Point, Kenai Peninsula,Alaska........................................ 150 ^

26. Geologic and topographic map of Red Mountain,Kenai Peninsula, Alaska.................. In pocket

27. Map showing mining claims at Red Mountain,Alaska........................................ 166

28. Plan and geologic map of the Star No. 4 orebody, Red Mountain, Alaska.................... 166

29. A, View, of Red Mountain, from the northwest; B, ** Banded ore 20 feet north of shaft, Star No. 4. 166

30. A, Banded disseminated ore, deposit No. 20, Red '"*'Mountain; B, Cnromite lens cut by fresh oliv- Tine dikelets, deposit No. 11, Claim Point..... 166 i

31. A, Drag fold in chromite, deposit No. 24, RedMountain; B, Drag fold, deposit No. 13, Red ^Mountain...................................... 166

32. Geologic map of Silver Hill, Spokane County,Wash,.................................... In pocket

33. Outcrop map of pegmatites in zone 1........ In pocket ^34. Geologic map of veins Nos. 1 and 2.............. 20055, Geologic map of vein No. 4...................... 20036. Geologic map of veins Nos. 5, 6, 7, and 8....... 200 <6*37. Geologic map of the vicinity of Nickel Mountain,

Douglas CoXinty, Oreg.......................... -20838. Topographic and geologic map of the nickel

deposit near Riddle, Douglas County, Oreg...., 208 ^ '

ILLUSTRATIONS V

Page Plate 39. Geologic sketch map of parts of the Steens and

Pueblo Mountains, Harney County, Oreg... In pocket 40. Geologic sketch map of the tunnel at the

Steens Mountain prospect..................... 250* 41. The lodes of the Fisher group.................. 250

42. Geologic and topographic map of the Lucky* - Strike group and adjacent ground............. 254

43. The lodes of the Mogul, Blair, and O'Keefe i, groups and adjacent ground................... 254

44o Geologic and topographic map of the Rabbit Holeand Red King prospects near Fields, Oreg..... 254

Figure 1. Index map of Idaho showing location of the BlueWing district................................ 3

2. Maps of prospect tunnels, General Electric- Miller group and Oompton claim............... 20

3. Geologic and topographic map of the Currier 1 mine, near Paisley, Lake County, Oreg........ 31

4. Index map showing location of Majuba Hill, Nev. 40 5 Generalized cross section of western end of

Mount Vernon district........................ 606. Vertical longitudinal section of the Mount Ver-

noh nickel-gold deposit...................... 727. Geologic sketch map of Round Valley Peak

* deposit...................................... 968. Geologic map of Hilton Creek deposit........... 989. Geologic map of the Pickup mine................ 101

10. Index map showing location of Bohemia Basin, v Yakobi Island, Alaska........................ 108

11. Index map of Alaska, showing area included inplate 24..................................... 140

12. Geologic map of Reef mine, Claim Point......... 15913. Geologic map of the Bluff No. 1 deposit, Claim

* Point........................................ 16114. Block diagram of deposit No. 5, Red Mountain... 16£

fc 15. Sketch map of Juneau No. 1 deposit, Red Moun tain. ........................................ 169

*i 16. Index map of Washington showing location ofSilver Hill, Spokane County.................. 178

^ 17. Geologic map of the walls and back of theinclined shaft in the pegmatite of zone 1.... 186

18. Geologic map of the tin-bearing pegmatite ofzone 1 on the 75-foot level.................. 196

19. Geologic map of vein No. 3..................... 19920. Index map showing location of the Riddle nickel.

deposit...................................... 20621. Diagrammatic sketch of a vertical section of

the mineral deposit at the Discovery work-* ings....:......,............................. 215

22. Composite and schematic profile of the south- ' * east side of Nickel Mountain and the adjacent

area, showing relationship of ore to topogra- j phy.......................................... 222

23. Index map of Oregon, showing the location of*k the Steens and Pueblo Mountains.............. 228

TABLES

Page Table 1. Assays of trench and drill-core samples from the

nickel-gold deposit near Mount Vernon. ......... 742. Analyses of representative nickel-bearing rocks.. 743. Results of flotation tests on sulfide-bearing

breccia. ....................................... 774. Results of flotation tests on silica-carbonate

rock.. ......................................... 77

A Page

Abstracts of reports............... 1, 23,39, 57, 79, 105, 139, 177, 205, 227

Acknowledgments for aid.............. 1-2,4, 24-25, 41, 59, 00, 106, -141-142, 179, 208, 229.

Adamson claims, features of. 91-92, pi. 15 Alaska, chrqmite deposits in......... 139-

175, pis. 24-31nickel deposits in 105-130, pis. 20-23

Antelope claims Nos. 1-10, featuresof........................ 25, pi. 7

Arizona mine, features of............ 257

B

Bishop, Calif., tungsten deposits 'near............. 79-104, pis. 13-19

Blalr claims, features of .252-254, pi. 43 Blue Boy claim, features of.......... 252-

253, pis. 42-43 Blue Bull group, features of....'.. 256-257Blue Wing district, Idaho, geology

of...................... 6-10, pi. 1tungsten resources of... 1-21, pis. 1-5

Bluff Ho. 1 ore body, features of 161-162 Bohemia Basin, Yakobi Island, Alaska,

field work in.................. 106geology of......... 109-117, pis. 20-22prospect pits in....... 132-130, pi. 23topography of.......... 107-109, pi. 20

Bureau of Mines, operations by... 179, 202

California, quicksilver deposits in 20-30 tungsten deposits in.............. 79-

104, pis. 13-19Callaghan, Eugene, and Lemmon, D. M.,-

Tungsten resources of the Blue Wing district, Lemhl County, Idaho................ 1-21, pis. 1-5

Carpenter and Brown prospect,features of.............. 95, pi. 16

Chipmunk mine. See Pickup nine. Chromlte deposits, Kenai Peninsula,

Alaska.......... 139-175, pis. 24-31Chromlte production, at Kenai Penin

sula, Alaska................... 141Chromite samples, analyses of........ 151,

158, 162-, 167, 170, 171, 174 Claim Point, Kenai Peninsula, Alaska,

chromite deposits at -156-162, pi. 25 ohromite reserves at.............. 158mining claims at.................. 157

Copper deposit, Majuba Hill, Nev.... 54-55Coyote Valley prospects, features of 103-

104 Crimson Rose claims, features of..... 253,

pi. 43 Currier mine, features of........... 30-33

Dorr, J. V. N., 2d, Reed, J; C., and,Nickel deposits of BohemiaBasin and vicinity, YakobiIsland, Alaska.. 105-138, pis. 20-23

Douglas County, Oreg., field work in 207nickel deposit in.. 205-226, pis. 37-30

P

Fisher group, features of 250-251, pi. 41

G

General ElectricrKiller mine, fea tures of...................... 19-21

General Electric Co., property of... 19-21

Page

Geologic maps:Blue Wing district, Lemhi County,

Idaho......................... pi. 1Bohemia Basin, Alaska........... pi. 20Kenai Peninsula, Alaska..... pis. 24-§6Lone Pine district, Washoe County,

Nev........................... pi. 7riajuba Hill, Nev................. pi. 9Mount Vernon district', Wash..... pi. 11Mount Vernon nickel-gold deposit,

Wash......................... pi. 12Pine Creek pendant, Inyo County,

Calif........................ pi. 16Silver Hill, Spokane County,

' Wash........................', pi. 32Steens and Pueblo Mountains,

Oreg......................... pi. 39Gianella, V. P., Smith, W. C., and,

Tin deposit at Majuba Hill, Pershing County, .Nev........... 39-

55, pis. 9-10Glass Buttes prospect, features of... 33*

36, pi. 8 Guild, P. W., Chromite deposits of

Kenai Peninsula, Alaska........ 139-175, pis. 24-31

H

Harney County, Oreg., quicksilverdeposits in................. 227-250

Hilton Creek prospect, features of.. 97-99Hobbs, 3. W., and Pecora, W. T.,

Nickel-gold deposit near Mount Vernon, Skagit County, Wash.... 57-

78, pis. 11-12Hobbs, S. W., Pecora, W. T., and,

Nickel deposit near Riddle, Douglas County, Oreg........... 205-

226, pis. 37-30Horse Heaven mines, Inc., operations

by............................. 249

Idaho, tungsten deposits in 1-21, pis. 1-5 Iina mine. Blue Wing district, Idaho,

history of development of...... 4-6tungsten production from.......... 4-6workings of............ 16-19, pis. 2-5

Ima Mines Corporation, operations by 5property of............ 16-19, pis. 2-5

Juneau Ho. 1 deposit, features of.... 169

K

Kenai Peninsula, Alaska, chromitedeposits in..... 139-175, pis. 24-31

field work in.................. 141-142geology of......... 142-150, pis. 24-26

Ledoux & Co., assays by.'............ 74-75Lenunon, D. M., Tungsten deposits in

the Sierra Nevada near Bishop,Calif............ 79-104, pis. 13-19

Lennon, D. M., Callaghan, Eugene,and, Tungsten resources of theBlue Wing district, LemhlCounty, Idaho........ 1-21, pis. 1-5

Lone Pine district, Washoe County,Nev., geology of....... 25-26, pi. 7

quicksilver deposits in 24-20, pis. 6-7 Lucky Strike group, features of...... 251-

254, pi. 42

VII

M Page

Majuta fault, features of... 48-49, pi. 10Majuba Hill, Hev., copper deposit at 54-55

geology of................ 41-47, pi. 9tin deposit at........ 39-54, pla. 9-10

Majuba Hill mine, workings of........ 47-48, pi. 10

Marquette, W. H., results of flota tion tests by................. 76-77

McGee Mountain prospect, features of 99-100

Millovitch prospect, features of..... 94-95, pi. 16

Mineral Dome prospect. See Rosa!mine.

Mogul group, features of.. 252-254, pi. 43 Mount Vernon district, Wash., field

work in........................ 59geology of.......... 60-64, pis. 11, 12history of mining in.............. 58

Muskeg bodies, features of 121-122, pi. 21

N

Nevada, copper deposit in........... 54-55tin deposit in........ 39-55, pis. 9-10quicksilver deposits In... 24-28, pi. 7

Nickel-gold deposit, Mount Vernon,Wash.............. 57-78, pis. 11-12

Nickel deposit, Riddle, Oreg......... 205-226, pis. 37-38

geology of............. 211-224, pi. 38Nickel deposits, Bohemia Basin,

Yakobl Island, Alaska.......... 105-138, pis. 20-23

history of development of......... 110Nickel Mountain, Dreg., analyses of

samples from..... 211, 213, 216, 220geology of......... 208-211, pis. 37-38

O'Keefe claims, features of.......... 252-254, pi. 43

Ore bodies, Silver Hill, SpokaneCounty, Wash................ 190-201

Ore deposits, Blue Wing district,Idaho......................... 10-16

Bohemia Basin, Yakobl Island,Alaska...................... 118-138

Kenai Peninsula, Alaska........ 150-154Lone Pine district, Washoe County,

Hev........................... 26-27Majuba Hill, Nov................. 49-55Mount Vernon, Mash............... .64-78Riddle, Oreg................... 211-224Sierra Nevada near Bishop, Calif.. 89-

104Steens and Pueblo Mountains, Oreg. 240-

258 Ore reserves, Blue Wing district,

Idaho.......................... 14-15Bohemia Basin, Yakobi Island,

Alaska...................... 127-132Kenai Peninsula, Alaska... 154-156, 166 Mount Vernon, Wash............... 71-78Riddle, Ores................... 224-226Sierra Nevada near Bishop, Calif.. 88-

89Silver Hill, Spokane County, Wash. 202-

203 Oregon, nickel deposit in............ 205-

226, pis. 37-38 quicksilver deposits in 30-36, 227-258

Pacific Nickel Co., operations by.... 50sampling by.................. 71,' 73-74

Page, Lincoln R., Tin and tungsten deposits at Silver Hill, Spokane County, Wash........... 177-

203, pis. 32-36 Pecora, M. T. ? and Hobbs, S. W.,

Nickel deposit near Riddle,Douglas County, Oreg........... 205-

226, pis. 37-38

Page

P.ecora, W. T., Hobbs, S. W., and,Nickel-gold deposit near Mount Vernon, Skagit County, Wash.... 57-

78, pis. 11-12 Pickup mine, features of.......... 100-102Pine Creek Canyon prospects, features

of............................ 92-93Pine Creek mine, workings of......... 89-

91, pis. 15, 16, 18 Pueblo and Steens Mountains, Oreg.,

quicksilver deposits In........ 227-258, pis. 39-44

Prospecting, suggestions for, at Ma juba Hill, Hev................ 53-54

in Blue Wing district, Idaho..... 15-16in Lone Pine district, Washoe

County, Nev................... 27-28

Quicksilver deposits, Steens andPueblo Mountains, Oreg......... 227-

258, pis. 39-44Quicksilver prospects in adjacent

parts of Nevada, California, and Oregon.......... 23-37, pis. 6-8

R

Rabbit Hole group, features of 256, pi. 44 Red Hawk mine, features of.......... 29-30Red King group, features of.......... 255-

256, pi. 44 Red Mountain, Kenai Peninsula,

Alaska,' chromlte deposits at... 163-175, pis. 26-31

chromite reserves at.............. 166mining claims at........... 165, pi. 27

Reed, J. C., and Dorr, J. V. N., 2d, Nickel deposits of Bohemia Basin and vicinity, Yakobi Is land, Alaska.... 105-138, pis. 20-23

Reef mine, features of............ 157-159Regal claims, features of......... 250-251Riddle, Oreg., nickel deposit at..... 205-

226, pis. 37-38 Riddle nickel deposit, history and

development of.............. 206-207Ross, C. P., Quicksilver deposits in

the Steens and Pueblo Moun tains, southern Oregon......... 227-

258, pis. 39-44 Some quicksilver prospects In

adjacent parts of Nevada, California, and Oregon......... 23-

37, pis. 6-8 Rossl mine, features of........... 102-103Round Valley Peak deposit, features

of............................ 96-97

Side Hill body, features of.......... 122-123, pi. 21

Sierra Nevada, near Bishop, Calif.,field work in.................. 80

geology of........... 82-88, pis. 15-16Silver Hill, Spokane County, Wash.,

field work in.................. 179geology of............. 179-190, pi. 32tin production from..............'. 178

Silver Hill pegmatites of zone 1,workings on..... 194-195, pis. 32-33

Silver Hill pegmatites of zone 2,workings on................. 195-196

Silver Hill pegmatites of zone 3,features of................. 196-197

Silver Hill pegmatites of zone 4,workings on.................... 197

Silvertown group, quicksilverdeposits of................... 28-29

Smith, W. C., and Gianella, V. P.,Tin deposit at Majuba Hill,Pershing County, Hev........... 39-

55, pla. 9-10 Spokane Tin Co., property of...... 177-178

INDEX

Page

Star No. 4 claim, features of........ 166-167, pi. 28

Steens Mountain prospect, featuresof.................. 249-250, pi. 40

Steens and Pueblo Mountains, Oreg.,field work in.................. 229

geology of............. 232-240, pi. 39quicksilver deposits in........... 227-

258, pis. 39-44 topography of.......... 230-231, pi. 39

Surprise group, features of.......... 255

Takanls bodies, features-of... 125, pi. 22 Tin and tungsten.deposits, Silver

Hill, Spokane County, Wash..... 177-203, pis. 32-36

Tin deposit, Majuba Hill, Nev........ 39-54, pis. 9-10

Tin production at Silver Hill, Wash.. 178 Tin-bearing pegmatites, Silver Hill,

.Wash, geology of....... 182-187, 191workings on........ 194-197, pis. 32-33

Tiptop claims. See McGee Mountainprospect.

Tripod bodies, features of 124-125, pi. 21 Tungstar mine, workings of.. 93-94, pi. 19 Tungsten deposits, near Bishop,

Calif.......................... 79-104, pis. 13-19

geology of........... 82-88, pis. 15-16

Page

Tungsten production, in Blue Wingdistrict, Idaho................ 4-6

In Sierra Nevada near Bishop,Calif......................... 81-82

Tungsten and tin deposits, Silver.Hill, Spokane County, Wash..... 177-

203, pis. 32-36Tungsten resources, Blue Wing dis

trict, Idaho......... 1-21, pis. 1-5Tungsten veins, Silver Hill, Wash.,

features of..... 197-201, pis. 34-36geology of........................ 187-

188, 191-192, pis. 34-36 Tunnel body, features of.. 123-124, pi. 21

U

U. S. Vanadium Corporation, propertyof.................... 89-91, pi. 18

W

Washington, nickel-gold deposit in... 57- 78, pis. 11-12

Works Progress Administration,sampling by............... 71, 73-74

Yakobi Island, Alaska, nickeldeposits....................... 105-

138, pis. 20-23

o509612 O - 43 - 2

UNITED STATES DEPARTMENT OF THE INTERIOR Harold L. Ickes, Secretary

GEOLOGICAL SURVEY W. C. Mendenhall, Director

Bulletin 931-A

TUNGSTEN RESOURCES OF THE

BLUE WING DISTRICT, LEMHI COUNTY

IDAHO

BY

EUGENE CALLAGHAN

AND

DWIGHT M. LEMMON

Strategic Minerals Investigations, 1941

(Pages 1-21)

UNITED STATES

GOVERNMENT PRINTING OFFICE

WASHINGTON : 1941

For sale by the Superintendent of Documents, Washington, D. C. ....... Price 30 cents

CONTENTS

T Abstract...............................Introduction...........................Geologyo...............................

Sedimentary rocks..................Igneous rocks......................Struc ture..........................

Ore deposits...........................Mlneralogy0 ........................The veins..........................Origin.............................Localization of ore bodies.........Size and grade of ore bodies.......Re serve s...........................Suggestion for further exploration.

Mines and prospects....................Ima..........................General Electric-Miller mine, Other prospects..............

Page 1 16788

101012131314141516161921

ILLUSTRATIONS

Page Plate 1. Geologic map of productive part of the Blue

Wing district, Lemhi County, Idaho....... In pocket2. Level maps and sections of the Ima mine

showing geology.......................... In pocket3<, Longitudinal projections on vertical plane

of the Ima mine..................... ....... 204. Composite level map of the Ima mine........ In pocket5. Maps of prospect tunnels, Ima mine............ 20

Figure 1. Index map of Idaho showing location of theBlue Wing district.......................... 3

2. Maps of prospect tunnels, General Electric- Miller group, and Compton claim.............. 20

III

-*

TUNGSTEN RESOURCES OF THE BLUE WING DISTRICT,

LEMHI COUNTY, IDAHO

By Eugene Callaghan and Dwight M. Lemmon

ABSTRACT

The Blue Wing district, Lemhi County, Idaho, is not only the principal tungsten mining district in the State but it has recently become one of the leading producers of tungsten in the United States. So far only one mine In the district Is productive, but other prospects are being actively developed.

The veins fill a complex group of fractures in quartzite of the Belt series near the border of a granite mass that does not crop out but is exposed in underground workings. The vein fill ing is mainly quartz, which encloses fluorite, orthoclase, rhodochrosite, huebnerite, pyrite, tetrahedrite, molybdenite, and minor amounts of other minerals. The minerals other than quartz have a rough zonal arrangement with reference to the granite. The ore mined has an average content of about 0.72 percent of huebnerite (manganese tungstate). This mineral occurs mainly in the wider parts of the veins, and ore shoots are confined to the relatively large veins close to the granite. The more numerous minor veins farther away are not regarded as of much promise.

The Ima mine has thus far yielded roughly 175,000 tons of ore. An estimated 50,000 tons remains in sight above the lower or main level; and, although the veins probably pinch downward, there may be 40,000 tons more below the present workings. Some ore has been found on adjacent ground, but here and in outlying parts of the district the present development is not enough to permit estimates of reserves.

INTRODUCTION

The Blue Wing district, in southeastern Lemhi County, Idaho,

is the principal tungsten mining district In the State and in

recent years has become one of the leading producers in the

United States. The present report summarizes the results of an

examination of the district made by Eugene Callaghan, assisted

from Sept. 8 to 22, 1940, by Charles Vitaliano and from October

12 to November 5 by D. M. Lemmon, Donald Wyant, and James Pol-

locko

2 STRATEGIC MINERALS INVESTIGATIONS, 1941

The staffs of both the Ima Mines Corporation and the Incan- *

descent Lamp Department of the General Electric Co. cooperated _f

to further the work in every possible way. Both companies sup- ^

plied accommodations for the field party, as well as maps, re

ports, information, and actual help with the field work. Mr.

Wo P. Barton, general manager, Owen Hickey, mine superintendent,

Carl Dice, engineer and mill superintendent, and Floyd Harper,

bookkeeper, of the Ima Mines Corporation, and H. H. Barrows,

manager, tungsten mine division, Incandescent Lamp Department, Jl

and Ployd Elliot, superintendent, of the General Electric Co., ^*

deserve particular mention. ^

The district is on the west slope of the Lemhi Range (fig. 1) "*

in T. 14 N., R. 23 E. Its sole producing mine, the Ima, is in +

sec. 23 on the north side of Patterson Creek, a mile upstream

from the small settlement of Patterson, which is at the mouth of -><

the canyon and on the east side of Pahsimeroi Valley. Mackay,

the shipping point and the terminus of a branch of the Union ^

Pacific Railroad, is 56 miles distant via Double Springs Pass,

or 100 miles distant through Challls, the route used when Double

Springs Pass is closed by winter snows. Salmon, the county

seat, is 68 miles northwest of Patterson. Most of the roads be-W

tween these different points are graded and parts of some are ¥

paved.»i

The Lemhi Range, which has a northwesterly trend, reaches

altitudes of more than 11,000 feet, or more than 5,000 feet

above the broad Pahsimeroi Valley. In the vicinity of Patterson

the western slope of the range, up to an altitude of 8,000 or "*

9,000 feet, is remarkably smooth and even, with an average gra- -'-

dient of 25°, and is little dissected between the V-shaped major «

canyons. The sides of Patterson Canyon near the Ima mine have . :

an average gradient of 35°. Jutting cliffs rise in irregular .^,

succession on the canyon walls and are separated by steep shal- ^

low gulches, which contain long talus slides and have alluvial

TUNGSTEN, BLUE WING DISTRICT, LEMHI COUNTY, IDAHO

117" 116 115° 114° 113° 112° III

25 0 25 SO__ 75 IOOMILES

Figure 1. Index map of Idaho ahowlng the location of the Blue Wing district.


cones at their mouths. The canyon bottom averages between 300

and 500 feet in widtho Patterson Creek and the other large

streams entering Pahsimeroi Valley have built huge alluvial fans

that reach nearly to the middle of the valley.

The Ima mine has been visited by several geologists and en

gineers. The deposit was described in some detail by Umpleby2/

and Livingston, and some facts regarding its minerals were re-3/

corded by Shannon. The mine has been mentioned briefly by4/Bell, and recent developments have been described by Barton and

5/Arentz. Development and production are briefly described in

the various chapters of Mineral Resources of the United States

from 1910 to the present and in the reports of the State Mine

Inspector of Idaho. An unpublished report on the Ima mine by

C. B. Pollock, of the American Smelting & Refining Co., illus

trated by detailed geologic maps and sections with assay fig

ures, and a report by Don Emigh on the reserves of the Ima mine

were made available to the writers of this paper.6/

According to Umpleby ~^ the veins in Patterson Canyon were

prospected for silver and gold as early as 1881, but their pre

cious-metal content was too low for profitable mining. Tungsten

was not discovered until 1903. In 1911 the first efforts were

made to recover tungsten at the Ima mine; a 50-ton concentration

mill was operated in 1912, and two shipments of concentrates

were made in 1913. At that time 2,000 feet of development work

had been done in all, on the upper and lower levels, and theI/

upper tunnel was 900 feet long. In 1914 J. Nolan leased the

I/ Umpleby, J. B., Geology and ore deposits of Lemhi County, Idaho: U. S. Geol. Survey Bull. 528, pp. 73-71*, 77, 79, 109-112, 1913.

2/ Livingston, D. C., Tungsten, cinnabar, manganese, molybdenum, and tin deposits of Idaho: Idaho Univ. Bull. 2, vol. lU, pp. 21-25, 1519.

V Shannon, E. V., Minerals of Idaho: U. S. Nat. Mus. Bull. 131, pp. U67-5bg, 1926.

U/ Bell, R. N., Idaho rare metals: Min. and Contracting Rev., vol. 37, no. ?7, p. 5, 1935.

%] Barton, W. P., and Arentz, S. S., Mining and milling tungsten at the Ima mine; Min. Gong. Jour., vol. 25» no. 8, pp. 16-19, August 1939-

6/ Umpleby, J. B., op. cit., p. 109.]J Livingston, D. C., op. cit., p. 21.

TUNGSTEN, BLUE WING DISTRICT, LEMHI COUNTY, IDAHO 5

mine but sold his interest to Callahan and Duffield, who mined

tungsten with little success in both the upper and lower tunnels.

They in turn sold to Jeffs and Johnson, who sunk a 70-foot In

cline, near the entrance of the lower tunnel, from which they

are said to have recovered 8 tons of tungsten concentrate in one

month in 1916o Prom May 1917 until January 1918 the mine was

operated by Nolan and D. R. Wheelwright. In 1927 and 1928 some

work was done by the Patterson Mines Corporation under lease§/from the Ima Consolidated Mining & Milling Co., but the work

yielded only a small output.

In 1934 the Ima Mines Corporation took over the property and

produced 2,300 pounds of concentrates averaging 56 percent of

WO o During 1935 development work was actively carried on, but 3

there was no production. Late in 1936 about 800 tons of ore was

mined and milled, and production has continued to the present.

Late in 1939 and early in 1940 the American Smelting & Refining

Co. investigated the deposit both by geologic mapping and by di

amond drilling. The mill recently has been enlarged to treat

120 tons daily. The metallurgical treatment involves crushing,

jigging, and grinding to 35 mesh in a ball mill, followed by an

other jigging, flotation, and tabling of concentrates. The Jig

and table concentrates are dried and passed through a magnetic

separator to take out metallic iron and then huebnerite. The

remaining concentrates, which consist mainly of sulphides, are

shipped to the smelter, and the huebnerite concentrate, which

averages 67 percent of WO,, eventually reaches the incandescent-o

lamp plant of the General Electric Co. In the fall of 1940

there were 20 men employed in the mill and 40 in the mine 0

Sj Campbell, Stewart, Annual reports of the mining industry of Idaho for the years 1927 and 1928, pp. 160 and 15^, respectively.

303579 0 41-

STRATEGIC MINERALS INVESTIGATIONS, 1941

Recent production of the Ima mine ia given in the table be

low. The mill heads have averaged 0.55 percent of WO , or very3

roughly 0.72 percent of huebnerite, and of this the mill re

covers about 75 percent. The ore has an average content of 1.75

ounces of silver to the ton, of. which 80 percent is recovered in

the sulphide concentrates. The sulphide concentrates recovered

average 4 percent of the ore treated and contain about 42 ounces

of silver to the ton, 0.01 ounce of gold, 3.75 percent of copper,

7 percent of lead, 28 percent of iron, 5 percent of zinc, 37

percent of sulphur, 1 percent of lime, 12 percent of insolubles,

and 0.5 percent of W0g 0

The ore also contains a variable amount of molybdenite,

averaging about 0.08 percent, but at present this is not savedo

Recent production of the Ima mine

-\ Q-*7 '

1938..................... ......

1939...........................

1 QA() ~J

rPr*'+'0 1

Huebnerite Concentrate (pounds)

174,800

077 noo

ZQQ OOP

360,177

1,210,805

Percentwo3

66.54

£z a i n

67»00

Sulphide Concentrate (pounds)

667.4

1,356.0

1,431.0

1,215.0

4 CCQ A

Includes 16,000 pounds of huebnerite produced in November and December 19367

2/ For 10 months, January to October.

In December 1938 the General Electric Co<> purchased some

claims from W. E. Miller and staked additional claims. This

ground has been actively prospected since March 1940.

GEOLOGY

The areal geology of the Blue Wing district shown on plate 1

is simple. The exposed rocks are pre-Cambrian quartzites of the

Belt series. These are rather gently folded, the main fold


being an anticline of northwesterly trend, traversed by the can

yon of Patterson Creek. No igneous rocks are exposed within the

area shown on plate 1, but granite has been reached in the work

ings of the Ima mine and small masses of quartz diorite and oth

er granitic rocks crop out in neighboring parts of the Lemhi

Range. The fracture system that controlled the distribution of

the veins is very complex in detailo The Ima vein zone has a

northwesterly trend, apparently parallel to the trend of the

arch in the quartzite, and is closely associated with the gran

ite.

Sedimentary rocks<.--The Belt rocks in the district were all

formed by the metamorphism of somewhat feldspathic sandstones

and shales. They mostly consist of beds of micaceous quartzite

6 inches to 2 feet thick alternating with thin slaty layers.

Some of the quartzite beds are finely laminated, and some show

cross lamination. The rocks are in general brownish to greenish

gray on weathered surfaces but light greenish gray to black

where fresh. Because of their micaceous character and numerous

minor fractures, the rocks break down where weathered more read

ily than most quartzite rocks. Within the mapped area the rocks

are uniform in character and lack beds of sufficiently distinc

tive appearance to be used as markers. In other parts of the

Lemhi Range these same quartzitic rocks locally contain lenses

of purple, maroon, and white to pinkish quartzite, especially in

the upper part of the unite

These rocks have a cleavage, which in most parts of the map

ped area is parallel to the bedding, but in some places the an

gle between the two is 20° to 30°. Closely spaced shear planes

have locally obliterated the bedding, and in a few places there

are small drag folds of about 10-foot radius. Near faults and

vein zones the bedding is obliterated in much of the hackly

structure of the rocks. Most of the metamorphism in the Belt

rocks is regional and antedates the intrusion of the granite


and the formation of the veins, but in a zone a few Inches wide

on the granite borders fine-grained biotite has been developed

in the quartzite.

Igneous rocks* The only igneous rocks visible within the

mapped area are the granite, and the small pegmatite veins that

locally accompany it, on and near the intermediate and lower

levels of the Ima mine, more than 300 feet beneath the surface.

The granite is pink and consists largely of orthoclase, with

abundant quartz, some plagioclase, a little biotite, and proba

bly some muscovite. All the granite so far revealed in the mine

workings contains quartz veinlets and disseminated sulphides and

fluorite. The orthoclase and quartz seem to have been unaffect

ed by the mineralization, but the plagioclase has been largely

.replaced by sericite and fluorite.

As shown on the maps of the intermediate and lower levels

(pi. 2) and as revealed in the adjacent stopes and raises, the

contact of the granite with the quartzite is very irregular.

Its average dip between the two levels is about 30° S., and

drill cores indicate that its dip beneath the lower level is 18°

S. The position of this contact with reference to the veins is

of economic importance, as the ore shoots thus far mined have

terminated at or near the contact.

Structure. The major folds in the Belt rocks of the Lemhi9/

Range trend nearly north. This fact was noted by Ross in an

earlier study of parts of the range farther north and east, and

he has confirmed this fact by more recent unpublished studies of

12/ an area closer to the Blue Wing district. Within the area here

mapped most of the dips observed between the Ima mine and the

front of the range are southwesterly, whereas east of this area

most of the dips are northeasterly,. Outcrops in the district

2/ Ross, C. P., The copper deposits near Salmon, Idaho: U. S. Geol. Sur vey Bull. 77^, P. 11, 1925.

10/ Ross, C. P., oral communication.


are not sufficient to define the structure clearly, but there

seems to be a local warp or arch in the mapped, area, with its

axial plane parallel to the vein system.

The fracture system as revealed in the underground workings

and by the distribution of veins on the surface is extremely

complex. The premineral fractures that determined the course of

the veins strike in general N. 20°-40° W. and dip about 60° W.

One productive vein,'however, at the east portal of the lower

adit of the Ima mine strikes N. 42° W. and dips 35° NE. Some

veins, moreover, strike northeastward, and dip either to the

northwest or to the southeast, but none of these have thus far

shown promise of being productive. At a few places on the sur

face these "cross" veins were observed to curve into the north

westerly system. The outcrop of the westward-dipping vein zone

along the steep canyon slope trends about N. 10° W. Where the

bedding strikes northwestward, the veins tend to follow the bed

ding. Such a bedding vein on the Mazda No. 28 claim of the Gen

eral Electric-Miller group yielded a small shipment of ore.

In addition to the veins and the gouge seams that follow

them, there are nearly flat or gently dipping fractures some of

which are premineral and some postmlneral. Examples of premin

eral fractures were observed in the long east crosscut -on the

lower level of the Ima mine, where a vertical vein between two

nearly flat fractures had narrower but uncrushed continuations

in the flat fractures. The vein is displaced, on the other hand,

by eastward-trending faults, the hanging walls of which are

shifted toward the west. These faults dip gently to the north,

as shown especially well on the upper level of the Ima mine.

The northern end of the upper part of the ore shoot on the Ima

mine intermediate level has been moved 32 feet to the southeast,

as indicated by the offset of the granite contact. These ob

servations, taken together, Indicate that such of the premin-

. eral fractures as were favorable in position arid attitude were

10 STRATEGIC MINERALS INVESTIGATIONS, 1941 .

mineralized and the others were not, and that there have been '

some relatively minor displacements since the vein was formed.

The fractures followed by the veins, as well as the veins

themselves, must have been formed later than the granite intru

sion, for no dikes of granite or other rocks follow the trend of

the vein system. It is thought that the fractures result from

disturbances during the closing stages of the granitic intrusion,,

ORE DEPOSITS

The tungsten ore bodies thus far found in the Blue Wing dis

trict are limited to the workings of the Ima mine, except that

exploratory work on the General Electric-Miller group has yield

ed enough ore for a test shipment. Only two small vein segments

were exposed at the surface on the Ima ground, and these pinched

out toward the northwest; the ore shoots opened in the past few

years were found by underground exploration. Huebnerite, the

tungstate of manganese, is the only mineral of economic impor

tance in the district. The silver, copper, and lead minerals

that first attracted the attention of prospectors have not

proved sufficiently abundant to be mined alone, although they

are valuable byproducts. The ore shoots in the Ima have been

large; the few shoots mined have yielded roughly 175,000 tons,

and 50,000 tons more is in sight above the lower level.

Mineralogy. The ore deposits are all quartz veins with

varying amounts of fluorite, orthoclase, and rhodochrosite as

the principal associated gangue minerals, and huebnerite, py-

rite, tetrahedrite, chalcopyrite, bornite, galena, sphalerite,

molybdenite, and scheelite as the principal metal-bearing miner

als. Weathering of the veins yields limonite pseudomorphous

after pyrite, together with azurlte, malachite, manganese ox

ides, cerargyrite, jarosite, molybdite, sulphur crystals, and

possibly other secondary products.


Fluorite, both greenish and purple, is the next most abun

dant gangue mineral after quartz. It is prominent only in a

zone extending 600 feet from the granite contact on the inter

mediate level, where it seems to bear a definite zonal relation

to the granite. Rhodochrosite, the most abundant carbonate, oc-.

curs at rather widely spaced intervals throughout the veins but

seems less abundant near the granite than at a distance from it.

Siderite appears in the concentrates, and other carbonates occur

in minute seams and vugs. Flesh-colored orthoclase occurs in

the veins near the granite contact, and scattered grains of it

have been found in veins at the surface. Micaceous aggregates,

apparently composed mainly of sericite, are present in many of

the veins, especially near the granite.

Pyrite is the most abundant of the metallic minerals. It

commonly forms cubical crystals, some of which are more than

half an inch in diameter. This mineral contains very little

silver and almost no gold.

Huebnerite is probably the second most abundant metallic

mineral in the ore. It is very widely though sparsely distrib

uted. The ore sent to the mill has an average content of only

0.72 percent of huebnerite, and in large quantities of vein

quartz the huebnerite is far less abundant. The mineral forms

reddish-brown prismatic crystals that in some specimens are more

than an inch long and average about a quarter of an inch in

width. Some of it is so soft and easily powdered that its re

covery in the mill is very difficult. Analyses of the huebner

ite from the district, listed by Shannon, 'show that it con

tains about 76<,3 percent of tungsten trioxide, 21.5 percent of

manganese oxide, and 2.2 percent of ferrous oxide. Scheelite,

the calcium tungstate, is present in very minor amounts, chiefly

in the veins near the granite. It is also scattered through the

ll/ Shannon, E. V., The minerals of Idaho: U. S. Nat. Mus. Bull. 131,P. U5g, 1926.


mineralized granite, but so sparsely that it has no commercial .+

value.; -

Tetrahedrlte, the sulphantimonate of copper, is the most .^

valuable and probably also the most abundant mineral after hueb-

nerite. It contains most of the copper and practically all of

the silver produced (see p. 6). It forms irregularly dissemi-4

nated grains and masses closely associated with pyrite and with

minor amounts of chalcopyrlte and bornite. Galena and sphaler

ite occur in very small grainso Molybdenite (molybdenum sul

phide) is disseminated in small grains in the granite, but it

occurs chiefly in veins in or near the granite, most typically

in sheets on fracture and shear planes, possibly sheared out "\

from its original position in veinlets where its easy cleavage -.;.

and softness has facilitated movement.

The secondary minerals, chiefly formed from the weathering -

of pyrite and tetrahedrite, are of no economic importance. Man

ganese oxides probably were formed from rhodochrosite or some _,

other manganese-bearing carbonate, or perhaps in part from hueb-

nerite, although huebnerite does not readily decompose, for it

has been found intact in places where the sulphides have been

completely oxidized.

The veins. The Blue Wing district contains a complex systemi1-,

of quartz veins, many of which are small and lenticular. Explo

ration has shown that a few of these, grouped close to the bor-'ig,

ders of the granite, are relatively large. At greater distances.^

from the granite the veins are more numerous but much smaller j

and less continuous. The original complexity of the vein system -f

has been somewhat increased by minor postmineral faults.

Most of the vein quartz contains metallic minerals, but it -4'

is only in a few ore shoots, most of which were discovered re- «

cently, that the huebnerite is abundant enough to be valuable. ^

In places the sulphides, the carbonates, and huebnerite have aI

banded arrangement; elsewhere they are distributed at random '


through the quartz. Fluorite occurs very irregularly in large

grains and aggregates. As noted above, there is a tendency to a

zonal arrangement of some of the vein minerals with respect to

the granite. Fluorite, molybdenite, and scheellte, for example,

are relatively abundant close to the contact, and rhodochrosite

is more abundant at a distance.

Locally fractures in the vein quartz are lined with micace

ous minerals, apparently derived from the quartzlte, and there

are some relatively large micaceous aggregates within the quartz

veins. Here and there angular fragments of the wall rock are

included in the veins. Some of these seem more micaceous than

the unaltered rock, as though .part of the quartz had been re

moved.

Origin. The huebnerite-bearing quartz veins are believed to

have been formed by the filling of fractures that opened during

the final stages of the intrusion of the granite, mainly in the

quartzite adjacent to granite but also in the outer parts of the

intrusive mass itself. The solutions that formed the veins fol

lowed openings outward from the core of the magma body and fill

ed them with the vein minerals. They also soaked out through

the previously consolidated border and left such minerals as

fluorite, pyrite, sericite, and molybdenite disseminated through

the granite. These replaced some of the earlier magmatic miner

als, chiefly plagioclase. Evidence of the close genetic rela

tion of the mineralized material to this particular body of

granite is afforded by the fact that the principal filled frac

tures are close to the granite and that certain of the vein min

erals within and near the granite have a zonal distribution.

Localization of ore bodies. The sizes and shapes of the

veins were determined by the character of the openings available

at the time of deposition. As noted below, the grade of ore in

creases in proportion to the width of the veins, so that the ore

shoots are confined to the larger parts of the veins. The

14 . STRATEGIC MINERALS INVESTIGATIONS, 1941

arrangement of the veins, described on page 12, appears to show

that distention of the quartzite by heat late in the course of

intrusion, followed by contraction on cooling, resulted in the

forming of a few large fractures close to the granite mass and

more numerous smaller ones farther away. Thus the valuable ore

shoots are confined to the quartzite within a few hundred feet

of the granite.

Size and grade of ore bodies. All the known ore shoots are

in the larger veins of the Ima mine. As shown on plates 2 and 3,

the ore shoots on the main level are all in a stretch that ex

tends 1,200 feet from the K. C. Li tunnel junction to the last

ore shoot in the granite. The slope distance from this level to

the top of the productive zone is 90 feet at the northwest end

of the mine, 175 feet at the 10B2 raise, 250 feet at the 201

raise, and 300 feet from the K. C. Li tunnel junction to the

highest stope on the surface. There are many pinches and swells.

The maximum length of a stope without a pinch is 250 feet. The

stopes above the lower level reach a maximum height of about 175

feet without a pinch. The shapes of the veins are shown by the

section (pi. 2); in vertical section as well as in plan they

show pinches and swells, and in the 10B2 vein is a wide roll

where the thickness of the vein normal to the wall is 35 fee.t.

According to Mr. Dice, the wide parts of the veins tend to be

richer than the narrow parts. Near the top of the productive

zone in the Bungalow 2 stope the vein averaged only 0.2 percent

of WO.,, whereas from the 10A1 to the 10B1 the stopes averaged

1 percent.

Reserves. The known reserves of blocked-out ore and proba

ble ore are limited to the workings of the Ima mine. According

to Mr. Dice, the stopes above the lower level still contain

50,000 tons of blocked-out ore, the average grade of which is

probably about the same as that of the ore previously mined--

0»55 percent of WO.,.

TUNGSTEN,_BLUE WING DISTRICT, LEMHI COUNTY, IDAHO 15

The probable ore, amounting to 40,000 tons, lies below the

lower level. This level, which shows much thinning and pinching

of the main vein, is evidently in the lower and narrowing part

of the productive zone., It is perhaps liberal, therefore, to

estimate that the probable ore body below the level in the main

vein has a length of 1,000 feet, a thickness of 5 feet, and a

- depth of 100 feeto The depth is estimated from the results of

diamond drilling, which Indicates that the granite slopes 18°

SEo and lies 300 feet below the lower level at the K. C. Li tun

nel junction, so that it probably does not cut off the produc

tive zone less than 100 feet below the level.

The west vein is so discontinuous or lenticular that no re

liable estimate of its quantity of minable ore seems possible.

It should be explored by conservatively placed crosscuts from a

level 100 feet lower.

A shoot of ore may remain in the so-called Talmadge vein,

which is exposed near the east portal on the lower level. Ex

ploration of this vein may open up another shoot with an addi

tional 50,000 tons of possible ore.

These estimates, totalling 90,000 tons of probable and pos

sible ore, should not be expanded until justified by further ex

ploration.

A little ore is exposed on the General Electric claims, but

this ground has not been much explored and has not yet been

proved to contain any appreciable tonnage of probable or possi

ble ore»

Suggestion for further exploration. The Ima Mines Corpora

tion plans immediately to run another level 100 feet below what

is now the lowest level in order to block out the remaining ore

in the lower part of the shoot. A drift extending southeast

ward, on this same new level, to determine whether another ore

shoot continues below and south of Patterson Creek is also

planned. This would necessitate drifting 450 feet to the south-


east end of the present productive zone and driving 500 feet

further to reach the area below the creek. Such work., with ap

propriately spaced crosscuts, should suffice to determine the

possible extent of the ore shoots. Probably one or two diamond-

drill holes ought to be sunk on the south bank of the creek be

fore driving on this lower level. The work done thus far above

the creek level on the south side of the canyon has not yielded

results encouraging enough to warrant its being extended farther

until the exploration below the creek level is completed.

The General Electric Co. plans to test its property with

diamond-drill holes, placing the first holes near the Ima ground;

and by correlating the results of this drilling with the infor

mation on surface and underground conditions already available

the company hopes to locate the granite contact and ore shoots

to the northwest. If the results of this work prove encourag

ing, other holes wil] be put down farther northwest.

The small veins and short lenses exposed on the surface have

been pretty well explored, and all appear to be discontinuous

and of low grade. They seemingly justify little further explo

ration.

The work done in the Blue Wing district was limited to the

area shown on plate 1, and the possibility that deposits of

huebnerite exist in other parts of the Lemhi Range was not

eliminated. There are numerous quartz veins in the parts of the

range that surround the area here described, and some of them

are somewhat similar mineralogically to those on the Ima ground.

MINES AND PROSPECTS

Ima,, The Ima Mines Corporation holds 21 patented claims and

15 unpatented claims in sections 13, 14, 23, and 24, T. 14 N.,

R. 23 Eo The company, which is purchasing the property from the

previous owner, is at present carrying on exploration, develop

ment, mining, and milling. Many veins crop out on the property,


but production has all been obtained from a single set of veins

that have been extensively explored and mined.

The geologic map (pi, 1) shows the relation of the mine

workings and vein outcrops to the topographic and geologic fea

tures of the district; and the geologic maps of the levels and

the geologic sections (pis. 2 and 3) show the principal features

of the vein system, which, except for a few small shoots in

granite, is wholly in the bedded and partly metamorphosed

quartz!tes of the Belt series. The Ima mine has three levels

(pi. 4), connected by raises and stopes, with drifts and cross

cuts totalling 10,016 feet. The original portal of the main, or

lower, level enters the steep canyon slope a few feet above the

creek at an assumed altitude of 6,294 feet. The K. C. Li tunnel

now affords a second entrance to this level. The upper adit is

200 feet higher. An intermediate level, roughly halfway between

the other two, does not reach the surface. The upper level en

ters the mountain on the outcrop of the main productive vein

zone, but a large part of its 2,265 feet of drifts and cross

cuts is included in a long crosscut to explore veins that crop

out to the east of this main zone. The main tunnel level con

sists of 5,266 feet of drifts and crosscuts, which explore one

vein zone for 350 feet, near the surface, and another for 1,200

feet. The total distance from the portal to the face is 1,700

feet. The intermediate level has 2,485 feet of drifts and

crosscuts. Practically no work has been done below the lower

levelo

One principal vein has been explored and mined throughout

its length on all three levels. A second vein, which has been

less productive, lies from 40 to 140 feet west of the main vein

and appears on both the intermediate and the lower level. Just

above the lower level the main vein assumes a gentler dip and is

dropped to the east by a normal fault, so that it appears on

this level as two veins, a west segment and an east segmento


The down-faulted segment probably does not extend far below the

levelo The general strike of the vein zone on the lower level

is northwest and its average dip 60° W. The veins pinch and

swell along the levels as well as up the raises, and in places

they are wavy in cross section. Faults that strike N. 70° E.

and dip 30°-70° No on the upper level offset the veins from 10

to 100 feet southwestward.

The sizes and shapes of the ore bodies, the grade of the ore

in them, their mineralogy, and other features have already been

described (see pp. 10-15).

On the surface above the productive part of the vein system

is the outcrop of a zone, roughly 100 feet wide and extending

northward from the upper adit for 1,500 feet, of branching and

unconnected vein lenses mainly less than 100 feet long and 3

feet wide. Some of these lenses contain a little huebnerite and

sulphides. Raises above the productive ore shoots show a simi

lar network of small veins. Most of these veins strike No 20°-

60° Wo and dip 35°-70° SW., but their outcrops on the steep

slope trend more nearly northward, as shown on the map. About

400 feet ea.st of the main vein on the upper level is another

vein zone that joins the first zone 800 feet above the upper

tunnelo It also consists of small discontinuous veins, and the

two crosscuts below this zone do not reveal any ore shoot, nor

do they give promise of any. Two short drifts (Talmadge and

lower Talmadge tunnels, pi. 5) show the nature of the veins in

the Ima No. 9 claim. Still farther east is a parallel zone of

small veins mainly dipping at angles of about 30° W. and showing

a little huebnerite at an inclined shaft. A vertical vein

(plo 5) in the Ima No. 6 claim, trending N. 35° W. is explored

by a drift 95 feet long. It is displaced at the base of the

tunnel by a longitudinal fault dipping 30° SW. A vein in the

Noo 3 claim (pi. 5) is explored for 130 feet by a tunnel on the

south side of the canyon. Another vein on the south side of the


canyon on the Ima No. 10 claim, opposite the Ima mine, trends N.

35° W. at the outcrop, which is 7 feet wide, but a crosscut be

low (pi. 5) revealed only a small unproductive vein. The Boise-

Ellis tunnel in the Ima No. 1 claim follows a 2.5-foot vein that

strikes N. 23° W. and dips 72° SW., samples from which contain

virtually no tungsten. The tunnel in the Ima No. 2 claim shows

a small vein striking N« 23° W. and dipping 75° SE. In the Ima

No. 8 claim two cuts and a 40-foot incline shaft for a length of

200 feet expose a 2-foot vein that strikes N. 60° Eo and dips

40° NW.

Nearby, in the Ima No. 14 claim, is another vein striking N.

18° W. and dipping 51° SW. It is 1.5 feet wide and contains a

little huebnerite and tetrahedrite. A group of small veins in

the Ima No. 19 claim follows the bedding, which strikes N. 15°-

30° W. and dips 11°-20° SW.

General Electric-Miller mine. The General Electric Co. has

acquired 48 lode claims northwest of the Ima Mines Corporation

ground. Those surveyed for patent, totalling 24, are shown on

plate 1. Ground for a mlllsite and for water rights has been

acquired near Patterson.

Only an experimental shipment of 40 tons of ore, taken from

a prospect pit in the Mazda No. 28 claim, has thus far been pro

duced on this property. This ore came from a bedding vein, ex

posed in a large pit, which strikes northwest and dips about 30°

SWo A tunnel nearby shows a 2-foot vein, probably the same one,

striking N. 40° W. and dipping irregularly 25° SW. (fig. 2)

A short tunnel (figo 2) below the twin shafts shows a vein

containing much manganese and copper stain and some huebnerite.

The vein strikes N. 33° W. and dips 80° NE. A lower crosscut

(fig. 2) shows no vein, and the quartzite is very slightly dis

turbed.

GEOLOGICAL SURVEY BULLETIN 931 PLATE 3

NW.SE.

UPPER LEVEL

INTERMEDIATE LEVEL

J * nMAIN LEVEL

PROJECTION ALONG EAST SPLIT OF MAIN VEIN

NW

MAIN LEVEL

PROJECTION ALONG WEST SPLIT OF MAIN VEIN

NW.

SE.

MAIN LEVEL

PROJECTION ALONG WEST VEIN

0 50 250 Feet __I Prepared by Carl Dice, of Ima Mines Corporation

LONGITUDINAL PROJECTIONS OF THE IMA MINEU.S. GOVERNMENT PRINTING OFFICE : 1941 O-303S79

GEOLOGICAL SURVEY

7'quartz

Sheared zone with many Quartz veinlers

TALMADGE TUNNEL Ima No.Qclaim

Shear zone

I'quartz

Sheared zone with many quartz veinlets

^^§>.70°.

LOWER TALMADGE TUNNEL Ima No.9 claim

BULLETIN 931 PLATE 5

3

SECTION

IMA No.6 CLAIM TUNNEL

N

A

2'quartz

Adit timbered and logged

Manganese stain but no huebnerite or sulphides.Quartz

ab^ crushed

lYz quartz with copper stain Shaft to surface caved. 4'barren quartz in face

IMA No.3 CLAIM TUNNEL

EXPLANATION

Fault

Vein±30°

Strike and dip

Vertical

BOISE ELLIS TUNNEL Ima No.I claim

4 quartz

6-10 quartz

.. No sulphides

QuartziteWinze 10'deep on 8" vein

8"quartz-%;V2"vein follows AT bedding

IMA No. IO CLAIM TUNNEL0

IMA No.2 CLAIM'TUNNEL 1OO Feet

MAPS OF PROSPECT TUNNELS, IMA MINEU.S. GOVERNMENT PRINTING OFFICE : 1941 O-303579

21

On the slope above the Ima mine in Patterson No. 2 claim are

a long trench and a short tunnel showing several bedding veins

mostly less than 1 foot wide and dipping gently to the southwest.

The Cowboy tunnel in Mazda No. 13 claim reaches two veins at

right angles to each other 120 feet from the portal Two pits

immediately above show the same or similar veins. The larger

vein is 1 foot wide, strikes'N. 80° E., and dips 62° NW. The

smaller strikes N. 20° W. and dips 60° SW» A short tunnel and a

pit on the south side of the gulch northeast of the cabins in

the Mazda No. 6 claim show a 1-foot vein striking N. 45° W. and

dipping 50° SWo

Several other small veins have been prospected to a slight

extent on the property.

The company is actively exploring the Mazda No. 20 and Pat

terson No. 2 claims by means of trenches and by a crosscut tun

nel, now 700 feet long, starting in the Mazda No. 33 claim and

aiming N. 50° E. for the mineralized ground on Mazda No. 20,

which will be reached at a depth of 650 feet. Diamond drilling

is also contemplated. Numerous pits and tunnels excavated on

the property by earlier prospectors reveal several small veins,

some of which contain huebnerite.

Other prospects. Alex Compton holds some claims.on the

north side of Patterson Canyon, east of the Ima ground 0 A small

vein containing huebnerite has been followed for 48 feet by a

small drift trending N» 10° W.

Huebnerite occurs in vein-quartz float on the Rosebud claims

on the northwest edge of the mapped area, beyond the General

Electric ground. The vein has not been found in place, although

several pits and a short adit have been dug in search of it.

O

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GEOLOGICAL SURVEY

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STRATEGIC MINERALS INVESTIGATIONS 1941 - … STATES DEPARTMENT OF THE INTERIOR Harold L. Ickes,...

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Transcript of STRATEGIC MINERALS INVESTIGATIONS 1941 - … STATES DEPARTMENT OF THE INTERIOR Harold L. Ickes,...