Clean artisanal gold mining: a utopian approach? · · 2016-04-27Clean artisanal gold mining: a...

Journal of Cleaner Production 11 (2003) 99–115www.cleanerproduction.net

Clean artisanal gold mining: a utopian approach?

Jennifer J. Hintona,b,∗, Marcello M. Veigaa,b, A. Tadeu C. Veigaa,c

a The Centre for Responsible Mining (CRM), Vancouver, Canadab Department of Mining Engineering, University of British Columbia, 6350 Stores Road, Vancouver, BC Canada V6T 1Z4

c GEOS - Geologia para a Minerac¸ao Ltda., Brası´lia, Brazil

Received 21 December 2001; received in revised form 15 February 2002; accepted 16 February 2002

Abstract

Artisanal and small-scale mining (ASM) provides an important source of livelihood for rural communities throughout the world.These activities are frequently accompanied by extensive environmental degradation and deplorable socio-economic conditions,both during operations and well after mining activities have ceased. As gold is easily sold and not influenced by the instability oflocal governments, it is the main mineral extracted by artisanal miners. Mercury (Hg) amalgamation is the preferred gold recoverymethod employed by artisanal gold miners and its misuse can result in serious health hazards for miners involved in gold extraction,as well as for surrounding community inhabitants, who may be exposed to mercury via the food chain. The rudimentary techniquescharacteristic of ASM result in a number of occupational hazards, other although most risks are primarily attributed to machineryaccidents and ground failure, such as landslides and shaft collapses.

Several technologies and methods commonly utilized by large-scale mining operations can be downsized to smaller scale oper-ations. However, the likelihood that miners will adopt these large-scale methods, or those developed specifically for ASM, dependsupon some key factors. For an artisanal miner, these factors include: (1) increased or comparable simplicity, (2) quick recovery ofthe economic mineral, and (3) demonstrated financial gain. Other practical aspects, such as the availability of materials (chemicals,steel rods, piping, generators, etc), capital and operating cost requirements and access to technical support, also influence acceptanceof new techniques.

This article will review four inter-related areas: first, the limitations and benefits, for ASM, of a number of specific technologies;second, the role of Processing Centers in education, information dissemination and provision of “clean” services; third, benefitsand challenges associated with formalization of ASM activities; and fourth, the contribution of ASM to the development of sus-tainability of communities, primarily through diversification of livelihoods. The appropriate application of technologies, particularlygiven the diversity of ASM communities around the world, will also be explored. 2002 Elsevier Science Ltd. All rights reserved.

Keywords:Artisanal mining; Small-scale mining; Mercury pollution; Mineral processing; Clean technologies; Processing centers

1. Introduction

Artisanal mining is an essential activity in manydeveloping countries as it provides an important sourceof livelihood, particularly in regions where economicalternatives are critically limited. The International Lab-our Organization estimates that the number of artisanalminers is currently around 13 million in 55 countries. Ithas further been extrapolated that 80 to 100 millionpeople worldwide are directly and indirectly dependent

∗ Corresponding author..E-mail address:[email protected] (J.J. Hinton).

0959-6526/02/$ - see front matter. 2002 Elsevier Science Ltd. All rights reserved.PII: S0959-6526 (02)00031-8

on this activity for their livelihood [1]. With increasingpopulation, particularly in developing nations, manyspeculate that involvement in these activities is likelyto escalate. Unfortunately, these activities are frequentlyaccompanied by extensive environmental degradationand deplorable social conditions, both during operationsand well after mining activities have ceased. Given thenumber of people directly or indirectly reliant on arti-sanal mining activities and the magnitude of resultingimpacts,appropriate measures must be developed andimplemented to mitigate associated problems.

This paper focuses on potential technical solutions forthe minimization of ecological and human healthimpacts derived from artisanal mining. However, the

100 J.J. Hinton et al. / Journal of Cleaner Production 11 (2003) 99–115

negative consequences of this activity are not a productof poor technical practices alone; the socio-economiccircumstances driving this activity must also beaddressed for any measure, technical or otherwise, tohave any enduring contribution to ASM communities.Based on past efforts to develop and implement cleanASM technologies, it is evident that in addition to takinginto account community-specific conditions, appropriateclean technologies must satisfy the following criteria:

1. Economically beneficial—The technology must beinexpensive to operate and it must generate obviousfinancial benefits.

2. Simple—The technology must be easy to use andwould ideally utilize readily available resources.

3. Expedient—The economic mineral must beefficiently recovered.

In this discussion, special emphasis is placed on thetreatment of gold-bearing ores. This is primarily as goldis, by far, the main mineral extracted by artisanal miners,but also because the environmental impacts generated byartisanal and small-scale gold mining, specificallyrelated to the discharge of mercury into the environment,warrant special consideration. Many of the technologiesand issues discussed, however, are applicable to otherminerals, and could therefore be considered in this gen-eral context.

2. Current practices in artisanal gold mining

The nature of ASM activities must be well understoodto successfully apply any measure to a given operation.ASM can be illegal or legal, formal or informal, and caninvolve extraction of primary or secondary ores. As well,not all ASM activities are defined by the size of the oper-ation, but may be better characterized by the lack oflong-term mine planning/control and use of rudimentarytechniques. In many regions in the Brazilian Amazon,for instance, a single artisanal mining operation movesas much as 4 million m3 of material annually.

ASM usually involves the extraction of secondarygold from alluvial, colluvial or elluvial material, (i.e. freegold that is easily concentrated by gravity processes).For soft materials, such as weathered ores, miners typi-cally employ hydraulic monitors, which involve thehigh-pressure application of water to ‘fl uidize’ looselyconsolidated materials. For alluvial ores, dredging of theriver bottom sediments is the preferred method.Hydraulic monitoring typically results in extensiveenvironmental degradation due to the sheer volume ofmaterial fluidized, the amount of water used and the lackof containment structures. Typical impacts include themodification of hydrologic regimes through creation ofvast tailings “beaches” and diversion of rivers. In the

north of Mato Grosso State, south of the Amazon basin,the impact caused by diversion of one river extended formore than 30 km.

Extraction of gold associated with primary ores (e.g.sulphide associated gold, often found at depth) can befar more complicated. Blasting with dynamite may berequired and, if the operation is not limited to a small-scale excavation at the surface, underground tunnellingpresents additional challenges (e.g. ventilation, hauling,tunnel stability, etc). Some operations extract gold fromquartz veins, which may contain extremely high grades(�10–20 g Au/tonne). Most gold is not occluded in sul-fides and can be extracted by amalgamation or cyani-dation without prior sulfide oxidation. Experiencedminers can recognize that once gold associated with pyr-itic quartz veins is encountered, this signifies the begin-ning of the end of their activities. Without access to tech-nical support, desperate miners invest in “miraculous”solutions to extract gold from sulfides with results oftenranging from ineffective and costly to environmentallydestructive.

Historic gold mining activities of colonial NorthAmerica are very similar to artisanal practices employedfor subsistence purposes today—both are characterizedby very rudimentary and labour intensive equipment andmethods. Mechanization significantly modifies ASMoperations as resource extraction can take place in amuch shorter time frame. As miners seek opportunitieselsewhere, this practice results in rapid abandonment ofcommunities, in addition to the degradation of hugeexpanses of land associated with the excavation of evengreater volumes of earth. Miners are eager to re-investprofits in expensive excavators, bulldozers and trucks,or look to private investors to scale-up production.Access to modern equipment, however, does not neces-sarily equate to efficient resource extraction. The situ-ation in Pocone, Brazil exemplifies what can occur whenmechanization is not accompanied by appropriate use oftechnology. At the beginning of the 1990s, more than4500 miners in 100 sites were mining low-grade quartzveins in highly weathered rock using trucks and shovels.In the absence of geological information and traditionalmining concepts such as planning, all of the capitalinvested in equipment was quickly lost. Even minerswho had previously produced 10 tonnes of gold werefacing bankruptcy. Because funding in Pocone and otherlocations is obtained outside of traditional financing sys-tems, miners pay a high price for these failed ventures,in some cases, with their lives.

Mechanization has also been important in increasingthe productivity of hydraulic monitors and dredgingoperations. While processing alluvial–colluvial terraces,hydraulic mining operations frequently use bulldozersand excavators to remove soil and waste material. Atthe beginning of the Amazon gold rush, mercury wascommonly spread on the ground in the belief that mer-

101J.J. Hinton et al. / Journal of Cleaner Production 11 (2003) 99–115

Plate 1. Miners in Ikabaru, Venezuela, using hydraulic monitor together with bulldozer.

cury moved throughout the dirt to capture all availablegold. This resulted in enormous mercury losses; in somecases up to ten parts of mercury per one part of goldproduced. Hydraulic operations usually employ riffled orcarpeted sluice boxes to concentrate gold prior to amal-gamation (Plate 1). In some cases the whole ore is amal-

Plate 2. Fluidized ore is pumped to sluice box. Mercury is eitherspread on the ground (above) or on riffled sluice box (below).

gamated directly in sluices on which mercury has beenspread (Plate 2). The heavy mercury-gold amalgam thatforms ‘sinks’ and is retained behind riffles or in carpetfibres. In these operations, large amounts of mercury aredirectly discharged with tailings.

From sophisticated barges to rafts floated by air-filledsteel drums, miners around the world use many types ofequipment to dredge river-bottom sediments. The “Guy-anese missile” , a significant improvement on currentmethods, is a cutter-head system that penetrates througha hardpan crust to access the underlying gold-rich gravel.This reduces the amount of fine sediments dispersedthroughout the river and avoids the fatalities that com-monly occur when men outfitted with crude diving gear‘vacuum’ bottom sediments through a pipe. Dilutedpulps of gold-rich gravel (usually 5% solids) are sentto the on-board sluice boxes. Tailings from sluices aredischarged back to the river generating a large siltplume. Other gravity separators, such as jigs or centri-fuges, are virtually never used to concentrate dredgedore. Gravity concentrates from sluices are sometimesamalgamated on-board using high-speed blenders, whichdischarge mercury-rich amalgamation tailings directlyinto rivers [2]. This practice creates “hot spots” , i.e. siteswith extremely elevated mercury concentrations. At thebeginning of the 1990s, on-board amalgamation usingcopper plates was also very popular in Latin America.Until 1991, more than 200 barges dredging the CaroniRiver in Venezuela discharged about 5 tonnes of mer-cury into the river as a result of the use of copper-amal-gamating plates [3]. This method lost popularity asminers realized that gold is lost with mercury due tofriction between gravel and amalgamated copper surface.

Currently, skilled miners only amalgamate gravityconcentrates (i.e. ore which has been crushed and separ-


ated by weight), a practice that contributes to significantreductions in mercury consumption and emissions.Approximately 14 grams of mercury are required toamalgamate 1 kg of concentrate (ratio Hg:concentrate�1:70) [3]. The undesirable mineral portion is separatedfrom the gold–mercury amalgam by panning either in‘waterboxes’ , in pools excavated in the ground or atcreek margins. The heavy mineral-rich amalgamationtailings frequently contain 200 to 500 ppm of residualmercury, which create ‘hot spots’ when discharged intoadjacent water bodies.

Excess mercury is removed from the amalgam by anancient filtration process of hand-squeezing through apiece of fabric. The excess mercury, usually more than90% of the mercury employed in the amalgamation, isre-bottled and used again. Once the amalgam is obtained,which typically contains ~60% gold, it is retorted or sim-ply burnt in a pan or shovel using a blowtorch. Theamalgam decomposition process (with or withoutretorts) produces a sponge-like gold dore that is sold togold shops in nearby villages or melted on-site.

3. Considerations for improvement andimplementation of appropriate technologies

Formal, large-scale mining operations employ a num-ber of innovative and efficient technologies, but mosthave not been effectively adapted or transferred to ASMoperations in the developing world. Technical alterna-tives derived from formal mining, or developed specifi-cally for ASM, must be thoroughly examined, pre-tested,appropriately modified and successfully transferred (e.g.through educational programmes) before ASM is likelyto transform into an environmentally sound and socio-economically sustainable activity.

To an extent, the adoption of new artisanal miningtechnologies has many parallels to the current movementtowards voluntary initiatives. The success of voluntaryinitiatives, which are measures undertaken by organiza-tions or individuals in lieu of or as a complement toregulations, is driven by the fact that obvious benefit(s),in addition to diminished ecological and human healthrisks, must be derived from any modifications to prac-tices [4].

For an artisanal miner, this means a method must befast, easy and cheap, i.e. any change should beaccompanied by a rapid rate of return, increased sim-plicity and a low investment (or reasonable investmentcountered with appreciable returns). An artisanal minerwill not pay out a dollar for a piece of equipment ortechnique that does not return two dollars [5]. Otherpractical aspects, such as the availability of materials(chemicals, mechanical components such as piping, gen-erators, etc) and operating costs influence the adoptionof any new technique. In order for a technology to be

successful, i.e. in that it is accepted and effectivelyapplied by miners, any measures should be pre-testedand accompanied by sufficient training [6]. If a measurehas been effectively demonstrated, miners will inevitablybe encouraged to continue implementing the method andmay be willing to attempt other “ innovations.”

Consideration of the diversity of backgrounds(cultural, religious, economic, etc), level of knowledgeand varied perceptions of individuals in ASM communi-ties is fundamental to the successful development andimplementation of technical assistance projects [7].Many miners are farmers, who mine on a seasonal basisto supplement their incomes. Other small miners workin more organized, albeit often superficial partnerships,with mechanized equipment and greater access toresources. Some communities are completely mar-ginalized and operate in a state of virtual lawlessness,with rampant drug and alcohol abuse, gambling, childprostitution and diseases, while other communities,although generally poverty stricken, maintain a greaterlevel of organization and sense of community. Varyingdegrees in permanence, adaptability to new methods, andother issues (age, gender), should also be considered inevaluating techniques. As it is well demonstrated thatprogrammes developed by the people participating inthem (i.e. bottom-up measures) tend to be most effectiveand enduring, alternative technologies would likely bemost successful if members of the local artisanal miningcommunity were directly involved with the developmentof any initiatives.

In addition to socio-economic conditions in ASMcommunities, the geological characteristics of eachdeposit also differ, thus, it is unreasonable to advocatea universal technical solution for all ASM activities. Inthe recent Workshop on Artisanal and Small-scale Min-ing sponsored by Mining, Minerals and SustainableDevelopment (London, Nov. 19–20, 2001), it was evi-dent that the production level and technological knowl-edge of miners in and throughout South America, Africa,Indonesia, China, Philippines and Africa can vary sig-nificantly, thus any solution must be tailored to meetlocal needs. It was also made apparent that efforts relatedto bringing solutions to the ASM sector are minusculewhen compared to the resources allocated to monitoringand characterization of ecological and human healthimpacts caused by poor ASM practices.

There is consensus among researchers, however, thatthe introduction of simple solutions to improve goldrecovery and reduce mercury emissions is possible.Priester et al. (1993) published an extensive review oftechnologies used in ASM and discussed their technicalappropriateness to small deposits around the world [8].In addition to the appropriate use of various clean tech-nologies, some fundamental information not directlyrelated to extraction techniques (e.g. health and wastemanagement issues) must also be conveyed to miners.


The topics outlined below consist of key gaps identifiedin ASM and possible measures to support the develop-ment of environmentally sound and sustainable oper-ations:

1. Determination of mineable reserves2. Gold liberation with comminution3. Improvement of gravity concentration4. Introduction of alternative processes5. Employment of safe cyanidation procedures6. Employment of safe amalgamation practices7. Health and Safety Precautions8. Ecological and human health impacts of mercury and

cyanide misuse9. Responsible waste management and reclamation prac-

tices10. Establishment of processing centres11. Development of organizations and partnerships12. Advancement of sustainable livelihoods.

3.1. Mineable reserves

Establishing mineable reserves is vital to creating asustainable operation as it: enhances the link betweenminers and the land they work; promotes planning thatmay be accompanied by an extended mine life; and itcan be used to obtain funding from formal financial insti-tutions, and therefore may encourage operation within aregulatory framework [9]. Currently, the prevailing tend-ency is to employ methods that make the most moneyin the shortest period of time, even in larger-scale ASMoperations using highly mechanized techniques.

A simple sampling programme using auger drillingcan be used to efficiently determine a minimum goldreserve that will support at least medium-term mineplanning. The effectiveness of this measure has beendemonstrated in Bolivia. As chemical analysis to estab-lish gold grades is complicated and costly, panning of a20-kg sample is sufficient to evaluate gold grades bycounting visible specks. Formal exploration companiesevaluating alluvial and elluvial material use a similarprocedure.

Based on more realistic reserves, rudimentary miningmethods evaluations and scheduling can be conducted.Even a basic mine plan will encourage consideration ofsafety precautions and improve miners’ capacity toanticipate problems. Concepts ranging from assessmentsof various mining methods, equipment maintenance,rock mechanics/stability and safety issues (ventilation,transport) should be introduced to miners. Productionmethods, including pre-concentration and pre-fragmen-tation, could even be coupled with mine plans to reducetransportation and mineral processing costs.

3.2. Comminution

Comminution involves the crushing and grinding ofore to reduce particles to a size suitable to liberate goldfrom gangue minerals through further processing (e.g.gravity concentration). Crushing and grinding are rela-tively simple mechanical processes, but are the mostexpensive unit operations in mineral processing. In ASMscenarios, comminution processes are severely limitedby the availability of resources such as electric gener-ators, fuel, steel rods or balls, and drums, particularly ifthese components require frequent replacement. As mostgold lost in tailings from ASM is in the coarse fraction(�1 mm) due to poor liberation, and the fine fraction(�0.074 mm) due to limitations in most gravity pro-cesses, it is apparent that more effective comminutionpractices can improve recoveries.

A number of crushing methods are used by artisanalminers throughout the world to process primary ores(e.g. quartz associated gold) including hammer mills(Kenya, Bolivia, Venezuela, Brazil), ball mills(Philippines, Tanzania), muller mills (China, Venezuela,Chile) and the locally developed Quimbaliticrusher/grinder (Peru) (Plate 3). As they are simple,robust, and capable of reducing ore to a treatable sizeusing a single unit, stamp mills are also in widespreaduse [10]. However, stamp mills cannot handle large vol-umes of material and may require upgrades to highercapacity units (e.g. jaw crushers and ball mills). Simplesledgehammers are common tools in less mechanizedartisanal operations.

Hammer mills are the most used grinders in LatinAmerica due to their ability to accept large pieces ofrock (as large as 10 inches), to operate dry or wet andto process large volumes of ore (as much as 100tonnes/h). Using swing hammers, these mills rotate atspeeds as high as 6000 rpm shattering ore to a size suf-ficient to pass through the output sieve. Quartz vein oresand their weathered portions can be discharged toscreens of 1 or 2 mm. [11]. As this type of equipmentwas developed to mill soft rocks, such as limestone,miners change hammer heads every 8 h when millinghard rock.

Even using highly mechanized methods, most gold isnot liberated through these comminution methods. Gold-laden tailings are subsequently re-processed, often usingthe same circuit. In many mining sites in the Amazon,fathers leave tailings for sons for re-processing, whosubsequently leave more for the next generation.Although this practice can allow multiple generations tosubsist, this hereditary activity is not in agreement with‘Best Practices’ or the principles of sustainable develop-ment. The best use of the natural resource impliesefficient application of techniques that allow reasonablegold recoveries with minimal energy consumption andwaste generation.


Plate 3. Quimbaliti Crusher in Peru (courtesy of Felix Hrushka).

Although material derived from comminution pro-cesses is suitable for other mercury-free concentrationmethods, mercury is still frequently added during crush-ing and grinding, gravity concentration or after. The ratioof mercury used to gold produced, can be as high as40:1, as can be the case for the quimbaliti crusher [12].In general, however, it has been found that when thewhole gold ore is amalgamated, the ratio of mercury lostto gold produced is around 3:1, compared to a ratio of1:1 when mercury is used with ground ore [3,9].

3.3. Gravity concentration

Attempts to introduce gravity concentration equip-ment to artisanal miners, such as shaking tables, spirals,automatic panners, centrifuges, etc., to eliminate mer-cury amalgamation have not succeeded. These methods,which use gravity to separate particles on the basis ofdensity or size to obtain a metal-rich final concentrate,can reduce mercury consumption, but they are still noteffective enough and further concentration with mercuryis generally needed. Gravity separation methodsimportant in ASM are described in Box 1.

Gravity separators, centrifuges in particular, have ademonstrated a capacity to concentrate fine gold,increase gold recovery and reduce the volume ofmaterial requiring amalgamation. The primary obstacleto widespread use of the most well known centrifuges(e.g. Knelson and Falcon) is cost. At least four manufac-turers in Brazil are producing crude and slightly lessefficient replicas of the Knelson concentrator, enablingincreased use by artisanal miners and improved goldrecoveries (Plate 4).

3.4. Alternative processes

Depending on the skills and financial resources ofminers, other beneficiation techniques can be used. Forinstance, froth flotation is the main process used by con-ventional mining companies to concentrate minerals,including gold. Chemical surfactants are used to recoverfine mineral particles from slurry by adsorbing to a par-ticle surface and rendering it hydrophobic. In gold flo-tation studies by Lins et al. (1994), concentrates wereupgraded from 13 g Au/tonne to 3000 g Au/tonne at 82%recovery using xanthate collectors [13]. Unfortunately, itis not trivial to submit 2–3 kg/tonne of concentrate todirect melting. Flotation using wooden cells or columnsis being conducted in Pocone, Brazil. Although flotationis a relatively complex process, it has enormous potentialto concentrate fine gold, achieving grades around 200g/tonne, and reduce the volume of material to be amalga-mated or submitted to cyanidation. Education of moreskilled miners in this process should be promoted atsome locations.

Some concentration processes have been devisedbased on site-specific mineralogy. Magnetic removalcoupled with blowing and tapping, which has beenemployed in ancient times in Ghana and the surroundingregion, involves the separation of most heavy mineralsfrom a gold concentrate using a hand magnet, followedby blowing and tapping of up to several kilograms ofconcentrate [14,15]. The magnet removes magnetite andhematite is separated by blowing and tapping, leavinggold behind (99.9% recovery). As this method is lessexpensive, faster and more effective than amalgamationat recovering fine gold, it is a promising alternative. The


Box 1Gravity Separation Methods

Sluice Boxes

� Riffled sluice boxes or carpeted sluices or trenches are angled such that heavy particles of gold settle out behind riffles orin carpet fibres.

� As the material must be fluidized in order for this process to work, artisanal miners commonly use substantial amountsof water and modify the hydrologic systems (e.g. river diversions, tailings beaches).

� The most commonly employed method (simple, cheap and fast).

Jigs

� Jigs induce density and size stratification of particles through a pulsating (up and down) motion.� A simple configuration consist of a screen overlying a tank containing liquid and a means of generating relative motion

between the liquid and material on the screen (air, water or mechanical), regulating water flow and recovering product.� Due to the limited number of moving parts and their simplicity, little maintenance is required.

Shaking Tables

� Shaking tables involve the generation of motion on an angled surface covered in parallel riffles, which induces separationof particles based on their densities and particle sizes.

� Efficiency is limited by the tendency of large high-density particles to have velocities comparable to small low-densityparticles when similar forces are applied. This results in high gold concentrations in the middlings (particles containingnon-liberated gold).

� Simple, easily modified method. Separation can be directly observed. However, limited to specific range of grain sizes,capacity is limited (~1.5 t/h), recirculation of middlings required.

Centrifugal Concentrators

� Centrifuges have the potential for primary concentration of fine gold or cleaning ordinary gravity concentrates.� Process uses a fluidized bed spinning-bowl that generates a centrifugal force that can reach up to 200 G and can process

up to 100 tonnes of solids/h. Concentrates can reach grades above 20,000 g gold/tonne in two stages (rougher andcleaner) and can be directly smelted, potentially avoiding an amalgamation step.

� Tend to be costly, but can be highly effective in terms of recovery and reduced mercury consumption.

Plate 4. Weathered ore is ground below 1 mm in a hammer mill thenfed into two 32 tonne-hour Knelson centrifuge replicas, Pocone, Brazil.

unique mineralogical characteristics of gold deposits inGhana, specifically the presence of flaky hematite, makethis technique feasible. Wind blown separation has alsobeen documented as a concentration process in Namibia,where women at the Uis tin mine lay out small woodentrays of crushed ore to be windsieved by the hot desertbreeze [16]. The presence of mica as the main impuritymakes this unconventional technique viable.

An innovative salt-electrolytic process to leach goldand residual mercury from concentrates has beendeveloped by the Brazilian Center of Mineral Tech-nology (CETEM) and tested in a pilot plant in theTapajos region of Brazil [17,18]. Using an electrolyti-cally generated sodium hypochlorite–chlorate solution,more than 95% of gold and mercury is dissolved andcollected on a graphite cathode within 4 h. The solutionis recycled, minimizing effluent discharge, and plastictanks are used, reducing investment and replacementcosts. The process has shown positive results in the oxi-dation of gold-bearing sulfide concentrates using sea-water as the initial electrolyte. The main drawback ofthis method is the need for trained personnel to controloperating variables (pH, current density, etc.) [3].


Coal–oil agglomeration techniques have some poten-tial, although they still require more skill and investmentthan amalgamation practices. Experiments have shownthat 90% of gold can be recovered when agglomeratedcoal and oil (5 mm diam) are contacted with pulpderived from gravity concentration [3]. Another processdeveloped by Envi-Tech Inc., Edmonton, Canadainvolves intense agitation of a concentrate-proprietaryadsorbent mixture for 5–10 min [19]. Subsequent separ-ation of gold from the adsorbent is conducted using frothflotation methods.

3.5. Cyanidation

Most organized mining companies use cyanide to dis-solve fine gold present in low-grade ores or in flotationconcentrates. When properly implemented, cyanidationcan yield high gold recoveries, but for artisanal minersthe process requires much more skill and investmentthan simple amalgamation. Gold is recovered from thegold-cyanide complex (Au(CN)2

-) in leachate throughprecipitation on the surface of fine zinc particles oradsorption onto natural or synthetic activated carbon.Coconut shell, for example, has the high ion exchangecapacity and porous structure needed for adsorption ofgold and gold complexes [20]. Carbon-in-pulp or car-bon-in-leach processes are rapidly replacing these recov-ery methods as they do not require the same degree offiltration and clarification and are effective for clayeysurface deposits.

Certain operating parameters, particularly pH and dis-solved oxygen, must be maintained to efficiently andsafely practice cyanidation. In order to prevent the lossof cyanide by hydrolysis and generation of harmfulhydrogen cyanide gas (HCN), agents such as lime (CaO)are added to the solution to maintain a high pH.Although sodium or calcium hydroxide is also effectiveat increasing pH, they have been demonstrated to inhibitgold dissolution, particularly at extremely high pH(�12). Lime has also been shown to enhance settling offine ore particles so that clear pregnant solution can eas-ily be separated from cyanide ore pulps. Oxygen isessential for gold dissolution in cyanide solutions and ithas been found that cyanide concentrations can bereduced by up to 25% if oxygen levels are high [21].Thus, simple oxygenating mechanisms, such as spargers,used in the leaching process may reduce cyanide con-sumption.

Although it is not widespread, artisanal miners arecurrently practicing cyanidation in a number of countriesincluding Peru [12], Ecuador [22], Colombia [23], Brazil[3], Philippines [24] and China [25]. Increased use inthe Philippines has been primarily attributed to supportfrom large mining companies, who have provided bothengineering expertise and capital, and the government,through provision of gold assaying services, chemicals

or facilitated borrowing agreements [7]. Other key fac-tors include the practice of purchasing or selling tailings,the presence of informal financing agreements betweenminers and gold buyers, and the availability of chemicals(sodium cyanide, zinc, activated carbon).

3.6. Amalgamation practices

Unskilled artisanal gold miners prefer amalgamation,as it is simple, cheap, quick and effective (mercury canextract more than 90% of gold from concentrates).Because the level of environmental pollution and relatedhuman health impacts strongly depend on the amalga-mation method employed, “cleaner” measures shouldbe promoted.

Amalgamation is efficient for particles coarser than200 mesh (0.074 mm) and for liberated or partially liber-ated gold [26]. With gold recoveries in excess of 90%,amalgamation can be improved when concentrates areprocessed in rolling barrels [27]. Two hours of operationprovides good recovery but also increases the “fl ouringeffect” (loss of mercury through formation of ‘ inactive’droplets), as is the case in when amalgamation is perfor-med in ball or rod mills. Some possible solutions are:shorter amalgamation periods, use of large rubber ballsto promote contact between mercury and gold particles,and application of oxidizing (e.g. KMnO4) or com-plexing (chlorides) reagents to clean gold surfaces andavoid mercury flouring [28]. Although chemical reagentscan improve gold and silver recovery, they may promotemetallic mercury dissolution and loss. Adding one gramof sodium hydroxide (NaOH) to every kilogram of con-centrate to be amalgamated can easily improve the effec-tiveness of the method. In many Latin American oper-ations, amalgamation in rolling barrels takes place in 30–50 minutes with the addition of one part of mercury to100 parts of concentrate [3].

Due to the inefficient use of traditional copper platesby artisanal miners, two Brazilian companies havemanufactured special silver-based amalgamation plates.As these plates have had considerable success in clean-ing mercury-contaminated tailings, they also have poten-tial for the amalgamation of gravity concentrates. Goldamalgamates with mercury on the plate surface and issubsequently scraped off and subjected to decompositionprocesses. Due to abrasion from sand and gravel on theplate surface, whole ore amalgamation will release mer-cury and is therefore not recommended. Electrolytic sil-ver plates have been used in Bolivia and Brazil, but theirprice is high and their efficiency in terms of mercuryretention is not known [29].

Amalgam decomposition can be done by retorting orthrough chemical processes, such as using nitric acid(30%). Nitric acid is very efficient but dangerous, ashighly toxic forms of mercury can be generated in theprocess. In the acidic solution, mercury is predominantly


found as mercury pernitrate (Hg(NO2)2.H2O), whosefumes are fatal to humans at concentrations of only 0.05mg/m3 of air. When mercury pernitrate contacts alcohol,fulminate (Hg (CNO)2) can be produced. This readilyexplodes when dry and is used in blasting caps and det-onators. Although most mercury in solution can be reco-vered by precipitation with aluminium (or iron or zincor copper) wires, artisanal gold miners in Colombia andGuyana directly discharge mercuric solutions into water-courses [30].

The preferred method for amalgam decomposition isopen-air burning (Plate 5). When this is conducted, asmuch as 50% of the mercury initially introduced into theamalgamation process is released into the atmosphere.However, when amalgamation is conducted properly andretorts are used, very little mercury is lost (as low as0.05%) [31]. A retort is a container in which the gold–mercury amalgam is placed and heated; volatile mercurytravels up through a tube and condenses in an adjacent,cooler chamber [9]. More than 95% of mercury can berecovered through retorting and it therefore contributesto significant reductions in air pollution and occupationalexposure. There are a variety of retorts on the market,some made of stainless steel while others use inexpen-sive cast iron. A homemade retort can be built with stan-dard plumbing pipe for less than US$10 (Plate 6) [32].Intermediate Technology Development Group (ITDG)has been promoting this retort in Africa, Philippines andSouth America.

UNIDO has distributed a number of Thermex glassretorts in Africa and the Philippines. As miners canobserve mercury being released from the amalgam andcondensed, they trust that all gold is recovered in the

Plate 5. Decomposing amalgam using a blowtorch.

Plate 6. Homemade retort (developed by Hypolito) made of plumb-ing connections.

process. Due to the low capacity (�30 g of amalgam),high cost (~1 oz gold), breakability and lack of spareparts, this alternative is not particularly popular.

A less expensive option for retorting has been appliedin Papua New Guinea and China [24,25]. The Chinesetwo-bucket retort consists of a metallic bucket and abowl filled with water (Fig. 1). A larger bucket coversthe first bucket containing the amalgam. The PNG “ tin-fish-tin” retort employs the same concept, but uses fishtins and wet sand instead of water. In both cases, theamalgam is heated using wood, charcoal or an electricelement and mercury vapours condense on the cover-bucket walls.

A crude method of retorting has been described in the“Gold Panner’s Manual” , a favourite of North Americanweekend prospectors [33]. This simply involves “bak-ing” the amalgam in the scooped out cavity of a potato.Readers are advised to not eat the potato after pro-cessing.

Despite the introduction of retorts through many pro-grams (CETEM, UNIDO, Projekt-Consult GmbH,ITDG, Organization of American States, etc) and obvi-ous benefits associated with their use, artisanal minersare reluctant, primarily due to a lack of concern forenvironmental and health impacts relative to other issues(i.e. the ease and speed of open-air amalgam burning)and the negligible costs savings from mercury recovery.Many miners in Suriname, Guyana and Venezuela reportthat bandits often attack during amalgam decomposition,thus a fast process can be crucial in some locations.

It is important that any initiative related to distributionof retorts should be accompanied by a strong educationalprogramme. Information packages (e.g. pamphlets,comics) must consider issues such as illiteracy rates,which can be high in many regions, and other social andcultural issues. In 1985, the Secretary of Mining of GoiasState, Brazil, started a campaign promoting retorts thatincluded a brochure illustrating the effects of mercurial-ism. Impotence was stressed as one of the initial symp-


Fig. 1. Two-bucket retort (left) and tin-fish-tin retort (right).

toms, which is somewhat inaccurate and therefore ques-tionable from an ethical standpoint, but was extremelyeffective in capturing the attention of miners. In general,the amount of money and effort spent in the educationof miners is considerably lower than those of otherapproaches, such as enforcement and monitoring.

Mercury recovered by retorting often does not havethe same amalgamating properties as new mercury. Inmany South American countries, miners simply dis-charge retorted mercury. The most efficient way toreactivate the surface of mercury is by using an ultra-sonic bath, such those used by dentists, wherein mercurydroplets coalesce in seconds (~US$200–400). A muchless expensive method involves electrolytic activationusing table salt and a simple battery to dissolve mercuryoxides from the mercury surface [34]. Any activationmethod should be accompanied by a process to retain thecontaminated water effluent, for example using lateriticmaterial or activated charcoal. Despite the small amountof effluent, some soluble mercury could be transformedto more toxic forms once discharged into the environ-ment.

At the end of the amalgamation process, miners selltheir gold dore to jewellers, banks or gold dealers innearby villages. These shops melt the dore containingabout 20 g of mercury per kg of gold [3] to volatilize(i.e. vaporize) the remaining mercury and any otherimpurities. Mercury levels inside these shops areextremely elevated. Fume hoods—if they are used atall—are usually rudimentary, consisting of only a fanthat blows mercury vapours into the ambient atmos-phere. As evidence suggests that most volatilized mer-cury is deposited near the emission source, exposure to

mercury vapour is extremely high for people living inclose proximity to gold shops.

In 1989, a Brazilian company, Apliquim, developed amercury condensing fume-hood consisting of a series ofcondensing plates coupled with iodide impregnated acti-vated charcoal filters (Fig. 2). This equipment reducesmercury emissions by more than 99.9% [27]. Less than40 µg/m3 of mercury was detected in the interior of agold shop using the prototype, compared with measure-

Fig. 2. The Apliquim fume hood.


ments as high as 300 µg/m3 in unprotected shops [35]1.A similar idea is being used in Venezuela where a gasscrubber (shower) using a potassium iodide solution cle-ans the fumes from the melting furnace. Introduction ofeffective fume-hoods to gold dealers is essential toreduce poisoning of operators and urban citizens.

3.7. Health and safety issues

A number of hazards exist in both surface and under-ground ASM operations. Although the chemical dangers,in particular associated with mercury and cyanide mis-use, first come to mind, most occupational hazards resultfrom poor physical conditions. In 1997 alone, 37 of 53mining-related deaths in Zimbabwe mines were attri-buted to ground failure, shaft collapses and machineryaccidents [10]. In Chinese small coal mines, at least 6000miners die annually [1]. In Hunan province alone, 70%of the 232 coal mine related deaths were attributed tomethane or coal dust explosions. Hydraulic monitoringof secondary deposits can also be extremely unsafe, asa potential exists to undercut hill slopes and generatelandslides. This was the case in Filadelfia, Colombia,where 51 miners were killed on November 22, 2001.Poor lighting and ventilation, electrocution and explos-ives misuse are other frequent causes of accidents [8].Dust producing silicosis and noise pollution are also per-vasive problems. Although accidents are underreporteddue to the illegality of ASM, ILO (1999) states that non-fatal accidents in ASM are still six to seven times greaterthan in formal, large-scale operations [1].

These tragic conditions are more likely a consequenceof economic demands, which result in inadequate equip-ment and neglect of safety measures (e.g. shaft supports),than lack of expertise, although insufficient training andawareness are undoubtedly critical factors. A joint pro-ject between the Canadian International DevelopmentAgency (CIDA), the British Columbia Ministry ofEnergy and Mines, and the Peruvian Ministry of Energyand Mines includes a component addressing manage-ment of health and safety issues in ASM. A detailedhandbook entitled “Safety and health in small-scale sur-face mines” by Walle and Jennings (2001), produced bythe International Labour Organization, includes simpleillustrations and examples for communication of safemining methods [36].

3.8. Impacts of mercury and cyanide misuse

The toxic forms of mercury of greatest concern inASM are mercury vapour and an organic form, methyl-mercury [37]. Mercury vapour released during amalgam

1 Background in cities is 0.01 µg Hg/m3, limit for public exposureis 1 µg Hg/m3 and limit for industrial exposure is 50 µg Hg/m3.

decomposition can be hazardous to artisanal miners orindividuals working or living near gold shops. Chronicvapour exposure can result in symptoms ranging frompsycho-pathological, such as depression and exaggeratedemotional response, to gingivitis and muscular tremors.Exposure to acute levels can produce dysfunction of kid-neys and urinary tract, vomiting, and potentially death.

Metallic mercury discharged into the environment(air, water, tailings) can be transformed into methylmer-cury, which is readily bioavailable and may be presentin increasing concentrations up levels of the food chain,particularly in aquatic systems (i.e. it is biomagnified).Individuals reliant on fish as a primary food source maybe particularly susceptible to accumulation of dangerouslevels of methylmercury. In cases of acute intoxication,muscular atrophy, seizures and mental disturbance areprominent. Methylmercury is easily transferred fromwomen to the foetus, with effects ranging from sterilityand spontaneous abortion, to mild to severe neurologi-cal symptoms.

Due to the importance of amalgamation, convincingminers to use less mercury due to health hazards is dif-ficult [1]. Lack of sanitation, widespread disease(malaria, cholera, STDs, etc.) and limited access tohealth care providers has resulted in generally poorhealth conditions in ASM communities. Consequently,any programme directed at reducing the comparativelyinvisible health impacts from mercury will be receivedwith minimal success if the program does not compre-hensively address these community issues also. On aver-age, ~40% of artisanal miners are women [38], thus agender sensitive approach is necessary to promotewomen’s involvement in the development and introduc-tion of measures. As women have little knowledge ofthe hazards associated with mercury (and they are lesssuited to labour intensive mining methods), they areoften selected to work in the processing aspect of ASM(including amalgamation). They are also predominantlyresponsible for food preparation, and as women of child-bearing age and children are particularly susceptible tomethylmercury exposure from fish, some educationalprogrammes should be specifically directed towardswomen.

A major concern with the promotion of cyanide useby artisanal miners relates to its toxicity. Cyanide is aneffective asphyxiant and hydrogen cyanide gas (HCN),which is generated at pH below ~11, can be fatal tohumans at concentrations around 250 ppm (276 mg/m3

at 25 °C) in air. Ingestion of cyanide in solution (CN�)can induce death at about 1–3 mg of cyanide per kg ofbody weight [39]. Due to the risks from cyanide misuse,the pH of cyanide leaching solutions must be carefullykept around 11 and 12 with the addition of lime (CaO).

Despite the dangers associated with cyanide, in areaswhere it is used extensively by artisanal miners humanfatalities from cyanide exposure are relatively minimal,


particularly when compared with mercury or other haz-ards. In Zimbabwe, for example, artisanal miners useabout 5000 tons of cyanide annually, but less than onefatality every 40 years is attributed to cyanide poisoning[40]. Cyanide can be transported and stored relativelysafely as sodium or potassium cyanide salt. If spilled,the immediate effects are dramatic, but cyanide generallydoes not remain biologically available in soils and sedi-ments as it quickly complexes with trace metals, volatil-izes or is metabolized by microorganisms. Some metal-cyanide complexes in aquatic systems, however, canremain stable for extended periods of time. As ASMwaste containment practices tend to be insufficient, sup-port (training and resources) for construction of safercyanide ponds may be needed.

3.9. Waste management and reclamation

Typically, solid or liquid wastes generated by artisanalminers are carelessly discharged to the nearby environ-ment. Simple settling ponds or tanks are relatively low-cost, easy to construct and are conducive to the segre-gation of tailings or potentially toxic chemicals (e.g.cyanide). Also, water separated from solids in settlingponds can be re-used in processes. The benefits of floc-culants were brought to the attention of miners in anexperimental processing centre established by CETEMin Pocone, Brazil in 1989 [11]. Some miners recognizedthe value of using these chemicals in settling ponds asthe rate of water reclamation doubled.

As transportation of tailings is easier in a fluidizedform, solid separation from fluids best takes place insedimentation ponds or lagoons. Ideally, artisanal minerswill select a site that is topographically amenable to tail-ings containment, for example, adjacent to hillslopes,and downgradient from the processing site. Dams shouldbe constructed to inhibit tailings dispersion and mobiliz-ation into waterways. Due to the potential magnitude ofimpacts from dam failure, consultation with qualifiedtechnical experts is strongly recommended throughoutdam design and construction. Extensive geotechnical andgeochemical expertise is needed to properly segregatewaste generated from ASM and mitigate related haz-ards—it is quite apparent that methods of disseminatingand promoting responsible waste management practicesto artisanal miners need further attention.

An alternative to small separate tailingsimpoundments has been proposed at Potosi, Boliviawhere 8000 miners were producing ~1500 t/day, whichwas processed at 40 separate flotation plants [41]. In1996, MEDMIN proposed a collective dam to receivetailings from the plants and an extensive consultativeprocess and feasibility studies were undertaken. TheGerman Financial Corporation (KfW) intends to fund thefinal design and construction (~US$ 4.5M) of the SanAntonio Tailings Dam, which will commence construc-

tion in 2002. This sort of “community” tailings dam pro-ject may prove to be a model for other locations wherea number of operations are active in a localized region.

In addition to pollution from various chemicals(mercury, cyanide, oils, etc), ASM can impact ecosys-tems through water siltation, hydrologic modificationsand extensive deforestation. The forest destructioncaused by artisanal miners is minimal in comparisonwith agricultural activities, but nevertheless is a notablecontributor. The main physical impact of ASM is usuallyassociated with careless tailings disposal that silt upwatercourses and divert rivers. Reclamation and reveg-etation projects with direct participation of artisanalminers have been conducted in Brazil and Venezuela. In1991, the US Forest Service Department trained Vene-zuelan professionals in revegetation of ASM sites. Usingmulches and a straw “carpet” with biodegradable plastic,the technique was transferred to miners to reclaim steephills. As most tropical countries are rich in lateritic soilswith a thin veneer of organic soil, the earthworm-gener-ated organic matter significantly improved soil quality.The local Association of Miners was fundamental inconducting these projects.

Another interesting example comes from Alta Flore-sta, an extensively mined region in the Brazilian Ama-zon. As ASM declined during the 1990s, populationsdrastically decreased from 120,000 to 38,000 and AltaFloresta was condemned to become a ghost town. Com-mercial goods from the region were not accepted in othercenters due to the risk of mercury contamination. Thelocal Government, together with Agriculture Cooperat-ives, developed solutions to return the region to its orig-inal vocation: agriculture and farming. Among otherideas, the use of abandoned open pits for aquaculturewas well received by the population. The newly estab-lished Aquaculture Association brought incentives tolocals and miners who found new reason to reside inthe region. In conjunction with this initiative, the StateUniversity of Mato Grosso and the Oswaldo Cruz Foun-dation have undertaken a meticulous monitoring pro-gram to assess mercury in the area [42].

3.10. Processing centres

Methods such as centrifugal concentrators, which canyield high recoveries even when compared with currentenvironmentally destructive techniques (i.e. mercuryamalgamation), continue to be overlooked by artisanalminers [7]. As these methods are generally more compli-cated and often require greater capital costs, processingat a central location may be beneficial for miners. Thesecentres may also promote formal economic arrange-ments or attract private investment, either of which canbe conducive to increased support from technical expert-ise (e.g. consultants) and acceptance by society and regu-


lators. With this, there is a greater likelihood of incorpor-ation of these miners within a legal framework [9].

An example of effective and creative amalgam pro-cessing is currently being applied in Venezuela, whereAmalgamation Centres have been constructed toincrease gold recovery and reduce mercury emissions[3]. Miners bring their gravity concentrates to these priv-ate or state-owned centres to be properly amalgamated,retorted and melted by specialized operators. In thegovernment-owned Amalgamation Centres in Vene-zuela, the service is free. Veiga and Beinhoff (1997)describe the many techniques that can be implementedto improve operation of Amalgamation Centres indetail [43].

The concept of Processing Centres was successfullyapplied to Shamva Mining Center in Zimbabwe, whichwas established by the Intermediate Technology Devel-opment Group (ITDG) in 1989. This facility providesaccess to a central mill for about 200 miners. In additionto processing services, the Shamva Center also providesdrilling and blasting services, ore transportation andtechnical support in areas such as mine planning, miningmethod selection, mine safety and pollution control [7].Shamva also supplies information on legal issues,geology and metallurgy and the selection and purchaseof technical equipment. A particularly interesting charac-teristic of the Shamva Center is that local miners areresponsible for their own ore throughout the milling pro-cess, although a plant manager provides supervision andassistance. Miners pay ~US$6 per h (~US$4/t) to usethe plant and take away the gold recovered (on average~5 g/t). Other payment agreements (e.g. based on esti-mated gold per tonne of unprocessed ore) resulted indisputes and were unsuccessful. Tailings generated fromore concentration contain gold that has been occluded inparticles or is sulfide associated—this gold (~1 g/t),which is recovered using cyanide, is a primary revenuesource for the Shamva Center. Ownership of the Centerhas recently been transferred to a commercial company,Shamva Mining Center (Pct) Ltd.

Experiences at cooperatives, such as the Shamva Min-ing Center in Zimbabwe, have demonstrated that theconcept of shared mining equipment is feasible and thesecenters can provide an important basis for training inprocessing methods as well as other fields (e.g. explo-ration, health and safety, etc). Using Shamva as a model,similar centres have been implemented by government,NGOs and private companies in other locations in Zim-babwe, as well as in Burkina Faso, Ghana, Mali andTanzania [44]. In another example, Proyecto Gama(Gestion Ambiental en la Minerıa Artesenal) hasrecently begun the design and engineering of a mercury-free artisanal processing plant in Peru [12]. Gamaintends to provide technical support for the project, butthe cyanide plant will be constructed and operated byartisanal miners.

A similar project has been proposed to the SurinameseGovernment by Healy and Veiga (1997) [45]. TheExperimental Mining Centers (EMCs) proposed for theinterior of Suriname would primarily function to providetraining and assistance and encourage the transformationof these activities to a legal, ecologically responsible andeconomically sustainable employment opportunity forthe impoverished people of the region. Specific miningclaims would be designated as experimental miningareas, wherein miners would be exposed to concepts ofgeological exploration, ore reserve estimation, miningand concentration techniques, environmental impact,water reclamation, tailing pond building, revegetation,safety issues, bookkeeping, etc., contiguous with goldproduction. In addition, the Center could improve theeconomic and social welfare of artisanal miners and theirfamilies by providing advice on obtaining legal mineraltitles, financial support, mine planning, occupationalexposure precautions, initiating alternative economicactivities and family matters.

The goals of EMCs are similar to the environmentalprogramme Manejo Integrado del Medio Ambiente en laPequena Minerıa (MEDMIN) (Integrated EnvironmentalManagement of Small Miners) sponsored by the SwissAgency for Development and Cooperation [29]. Thisprogramme, which contributed approximately $4 millionover six years, has involved education programs com-bined with technical and environmental studies at theSan Simon small mining area in Bolivia. It has beenestimated that San Simon was discharging about 1900kg of mercury into the environment (air, tailings, water)per month. An alternative to the mercury-intensive mill-ing process was devised using 6 m long sluices linedwith specific types of carpets. As gold recoveries werecomparable and in some cases higher using the mercuryfree process, the local small mining association wasencouraged to sign an agreement with MEDMIN, its pri-mary goal being mercury reduction, and a pilot plant wassubsequently constructed. Although mercury amalga-mation is still used in this plant, only a maximum of 3%is lost. With the new plant, gold recovery has increasedby ~10% and costs decreased by 10%—it is not surpris-ing that local miners have been willing to re-evaluatetheir practices and commit to mercury reductions.

A UNIDO supported Processing Center will soon beinitiated in the Tapajos region, Brazil. Covering 100 km2

and involving 90,000 miners throughout the 1990s,Tapajos is the world’s largest artisanal gold miningreserve. More than 1000 tonnes of gold has been pro-duced and an equivalent amount of mercury emitted tothe environment since 1958 [46].

3.11. Organization and partnership

In many operations, the ability to exploit more com-plicated deposits (e.g. primary ores, typically at depth)


is limited not only by technical capability (i.e. expertiseand mechanization), but access to capital to acquire tech-nical resources [9]. Financial institutions are unlikely tolend money in the absence of proven reserves and a cred-ible reputation. Due to the obvious risks associated withASM, if funds are provided, interest rates tend to beexceptionally high. The role of alternative lendingorganizations (e.g. IFC, NGOs) may be crucial to theadvancement of ASM operations. Alternative means toobtain financing include joint ventures, leasing of equip-ment and equity participation [41].

Organizing ASM activities, for instance through cre-ation of Miners’ Association, has been recognized as akey step in mitigating the risks from this activity. This isattributed to, in part, improved access to formal fundingsources and the introduction of clean techniques. MostASM meetings in the mid-1990s focused on formaliz-ation of activities. If miners could obtain legal titles, theywould be required to satisfy legal requirements forenvironmental practices, something that necessitates adegree of organization [9]. However, any legalizationstrategy must consider that (1) miners will undoubtedlywork outside of a regulatory framework if obvious bene-fits cannot be derived from operating within it [47] and(2) many miners do not have the resources or skills toparticipate effectively. Skills in many areas, includingbasic literacy to bookkeeping, as well as technicalexpertise, require supplementation. History has taught usthat it seems more practical to organize and then legalizethan vice-versa.

The Kias Explorer’s Association at the Kias Mine inthe Philippines is an example of miners uniting to oper-ate within a legal framework in order to sustain viablelivelihoods [48]. Financing for the association is gener-ated from membership dues, milling fees and the pro-vision of labour and energy (diesel engines) by individ-ual miners. Miners, who previously had basic miningskills or were self-taught, work in small cooperatives(“companhias” ) that typically operate separate gravityseparation methods (ball or rod mills and sluices).Cyanidation units and electrowinning are carried out ata central facility. Payment is through profit sharing oron a per diem or output basis. Although mercury is notused at Kias and the Association is involved in environ-mental endeavours like a local tree planting program,waste is discharged into the environment at any oppor-tune location, illustrating a common shortcoming in theASM sector. Practical assistance is needed in a numberof areas, including financing, energy sources, safetyissues and equipment to viably mine a deep deposit.

Development of organized ASM requires a systematicapproach that is appreciative of the challenges facingartisanal miners. Key steps identified by a UNIDOExpert Group (1997) include: legalization and develop-ment of appropriate regulation of ASM activities andtraining of key government and institutional representa-

Fig. 3. Key elements of organized artisanal mining.

tives; a site-specific assessment of the viability of certaintechnologies given the environmental, social and econ-omic conditions; and the design and implementation ofappropriate technologies [49]. Elements of this approachare shown in Fig. 3 and discussed in greater detail inwork by Veiga and Hinton (2002), Veiga (1997),Dahlberg (1997), Bugnosen et al. (2000), Barry (1995)and Davidson (1995) [3,6,9,47,49,50].

3.12. Development of sustainable livelihoods

In a detailed report on sustainable development in arti-sanal mining presented at a UNIDO Expert Group Meet-ing, Dahlberg (1997) articulated the value of artisanalmining in terms of alleviating poverty and contributingto the development of rural communities [49]. It isapparent that ASM can provide a viable means ofemployment for a limited number of people. However,ASM can also contribute to sustainable development ofthe surrounding community by using approaches similarto those adopted by many large-scale, formal miningcompanies; this primarily consists of support for auxili-ary enterprises (e.g. jewellery production) and agricul-tural development. This utopian image of artisanal min-ing communities working together with a commonvision is, however, highly improbable, at the very leastuntil any type of organization of mining activities hasoccurred.

Few livelihood diversification initiatives have beenimplemented in ASM communities, but the importanceof this issue has prompted a number of related programs.The UN Department of Economic and Social Affairs(DESA) has developed a program to produce policyoptions and best practices for poverty eradication, privat-ization, sectoral interlinking and privatization in ASM[51]. This project will be conducted in conjunction withthe UN Development Programme (UNDP), who has also


outlined a strategy for the development of sustainablelivelihoods and in ASM communities [38,52].

One positive example can be found in the Tapajosregion, Brazil, where the end of easily extractable goldhas driven small entrepreneurs to invest in cattle farm-ing, palm tree and “acaı-nut” production. In order to sup-port transportation of agricultural products, roads wereconstructed or upgraded. This is a significant improve-ment as, in mining times, all transportation was by air-plane. Governments and NGOs are also implementingjewellery schools in existing mining areas to add valueto the miners’ product.

Large-scale mining companies can play an importantrole in promoting sustainability of ASM communities.Prompted by reports of invasions and violence from arti-sanal miners, many companies have recognized thatASM represents a socio-political risk that must be con-sidered through all phases of a project. In response todisruption of ASM activities and dislocation of peopleresulting from expansion of a nearby mine in Mali, theSadiola Gold Mining Project was created by AngloGold. This project provides technical assistance andresources to further ASM, as well as alternative revenuegenerating activities, such as agriculture, jewellery pro-duction and fabrication of dyes and soaps [53].

One of the best-documented examples of coexistencebetween company and artisanal miners is Placer Dome’sLas Cristinas Project in Venezuela. Movement of minersto lands owned by Placer Dome Inc. stimulated supportfor a technically assisted partnership with local miners,including development of a semi-mechanized, environ-mentally sound mine [54]. The company recognized thesocio-economic importance of the miners in the regionand created a mechanism to help them organize andaccess better technology. This type of partnership shouldbe promoted but it is important that large companies arewell prepared to understand the complexity of theASM world.

4. Conclusions

It seems a utopian concept, but the principles of sus-tainable development could, in fact, be applied to theorganization of ASM and creation of better living con-ditions in communities facing immense social, environ-mental and economic challenges. Sustainable develop-ment in mining involves the realization of a net benefitfrom the introduction of mining through to the closureof the mine and beyond [55], but it is evident that thetools to do so are lacking at all stages of ASM.

With the scarcity of easily extractable gold ores, arti-sanal miners in many countries have begun to work withmore complex, often deeper ores that require greaterinvestment and expertise. Unskilled miners first usegreater quantities of mercury to increase gold recovery

and, when this proves ineffective, later seek technicalassistance. Normally, this support is not available.Engineering companies usually refuse to help artisanalminers and hiring consultants is costly. Local govern-ments are not prepared to provide specialized personnelor appropriate technology, and research institutionsprimarily offer high-tech methods. In these situations,artisanal miners will adopt an alternative technique outof necessity, but it will not necessarily be safe or parti-cularly effective. Clean ASM is a possible option butrequires assistance from governments, technical experts,researchers and NGOs to transfer information to minersand create demonstration projects.

Although it is evident that ASM can be an importantcatalyst for other entrepreneurial activities, the potentialbenefits from this activity have not been fully explored.Measures such as the development of alternative econ-omic activities (e.g. jewellery, agriculture, etc) and for-malization itself could significantly contribute to com-munity development. Any efforts by external parties(e.g. NGOs, government) are more likely to succeedwhere structured, locally based organizations or associ-ations are present and measures to support formalizationof activities and related development initiatives aredriven by members of the ASM community (i.e. bottom-up measures). As this is commonly not the case, meas-ures to enhance the capacity of the community todevelop formal partnerships or cooperatives and explorecommunity strengths and opportunities must be under-taken.

Capacity building exercises in the developing worldmust be conducted with thoughtfulness and sensitivity.Lessons learned in mining and similar sectors indeveloping nations have indicated that local individualsand/or groups should participate in assessments ofindigenous knowledge, community strengths and risks,resource factors (availability, quality, public services,etc), as well in development of any programmes. It isalso essential that the ASM community is incorporated,wherever possible, into the decision-making processwhen external parties undertake technical, social and/orenvironmental studies and initiatives.

Simple techniques such as homemade retorts, can bebrought to the attention of miners but individual or iso-lated solutions have not been durable, particularly in theabsence of strong educational support. Processing orExperimental Mining Centers have a demonstratedability to reduce mercury emissions and establish con-cepts of organization and citizenship in an ASM com-munity. In the next decade, the formal gold mining com-panies of the world are expected to amalgamate into afew gigantic organizations, adsorbing any remainingmid-sized companies in the process. With proper sup-port, ASM could occupy the gap between small andlarge-scale mining and contribute to the development ofresilient, sustainable communities.


Acknowledgements

The authors would like to thank the Natural Scienceand Engineering Research Council of Canada (NSERC),operating grant #217089-99, for sponsoring thisresearch.

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