Journal of Cleaner Production, March 2003,Vol.11, Issue 2, pp. 99-115. Clean Artisanal Gold Mining: A Utopian Approach? Jennifer J. Hinton1,2, Marcello M. Veiga1,2, A. Tadeu C. Veiga1,3 1. The Centre for Responsible Mining (CRM), Vancouver, Canada, [email protected] 2. University of British Columbia, Dept. Mining Eng., Vancouver, Canada, [email protected] 3. GEOS – Geologia para a Mineração Ltda., Brasília, Brasil, [email protected] 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 of local governments, it is the main mineral extracted by artisanal miners. Mercury (Hg) amalgamation is the preferred gold recovery method 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 techniques characteristic of ASM result in a number of occupational hazards, other although most risks are primarily attributed to machinery accidents 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 operations. However, the likelihood that miners will adopt these large-scale methods, or those developed specifically for ASM, depends upon some key factors. For an artisanal miner, these factors include: (1) increased or comparable simplicity, (2) quick recovery of the 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 acceptance of 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, benefits and challenges associated with formalization of ASM activities; and fourth, the contribution of ASM to the development of sustainability of communities, primarily through diversification of livelihoods. The appropriate application of technologies, particularly given the diversity of ASM communities around the world, will also be explored. Keywords: Artisanal mining; small-scale mining, mercury pollution; mineral processing; clean technologies, processing centers. 1. INTRODUCTION be addressed for any measure, technical or otherwise, Artisanal mining is an essential activity in many to have any enduring contribution to ASM developing countries as it provides an important communities. Based on past efforts to develop and source of livelihood, particularly in regions where implement clean ASM technologies, it is evident that economic alternatives are critically limited. The in addition to taking into account community-specific International Labour Organization estimates that the conditions, appropriate clean technologies must satisfy number of artisanal miners is currently around 13 the following criteria: million in 55 countries. It has further been 1. Economically beneficial – The technology must extrapolated that 80 to 100 million people worldwide be inexpensive to operate and it must generate are directly and indirectly dependent on this activity obvious financial benefits. for their livelihood [1]. With increasing population, 2. Simple – The technology must be easy to use and particularly in developing nations, many speculate that would ideally utilize readily available resources. involvement in these activities is likely to escalate. 3. Expedient – The economic mineral must be Unfortunately, these activities are frequently efficiently recovered. accompanied by extensive environmental degradation and deplorable social conditions, both during In this discussion, special emphasis is placed on the operations and well after mining activities have treatment of gold-bearing ores. This is primarily as ceased. Given the number of people directly or gold is, by far, the main mineral extracted by artisanal indirectly reliant on artisanal mining activities and the miners, but also because the environmental impacts magnitude of resulting impacts, appropriate measures generated by artisanal and small-scale gold mining, must be developed and implemented to mitigate specifically related to the discharge of mercury into associated problems. the environment, warrant special consideration. Many of the technologies and issues discussed, however, are This paper focuses on potential technical solutions for applicable to other minerals, and could therefore be the minimization of ecological and human health considered in this general context. impacts derived from artisanal mining. However, the negative consequences of this activity are not a product of poor technical practices alone; the socio- economic circumstances driving this activity must also 99 Journal of Cleaner Production, March 2003,Vol.11, Issue 2, pp. 99-115. 2. CURRENT PRACTICES IN ARTISANAL GOLD MINING The nature of ASM activities must be well understood to successfully apply any measure to a given operation. ASM can be illegal or legal, formal or informal, and can involve extraction of primary or secondary ores. As well, not all ASM activities are defined by the size of the operation, but may be better characterized by the lack of long-term mine planning/control and use of rudimentary techniques. In many regions in the Brazilian Amazon, for instance, a single mining operation moves as much as 4 million Plate 1 - Miners in Ikabaru, Venezuela, using m³ of material annually. hydraulic monitor together with bulldozer. ASM usually involves the extraction of secondary addition to the degradation of huge expanses of land gold from alluvial, colluvial or elluvial material, (i.e. associated with the excavation of even greater free gold that is easily concentrated by gravity volumes of earth. Miners are eager to re-invest profits processes). For soft materials, such as weathered ores, in expensive excavators, bulldozers and trucks, or look miners typically employ hydraulic monitors, which to private investors to scale-up production. Access to involve the high-pressure application of water to modern equipment, however, does not necessarily ‘fluidize’ loosely consolidated materials. For alluvial equate to efficient resource extraction. The situation in ores, dredging of the river bottom sediments is the Poconé, Brazil exemplifies what can occur when preferred method. Hydraulic monitoring typically mechanization is not accompanied by appropriate use results in extensive environmental degradation due to of technology. At the beginning of the 1990s, more the sheer volume of material fluidized, the amount of than 4,500 miners in 100 sites were mining low-grade water used and the lack of containment structures. quartz veins in highly weathered rock using trucks and Typical impacts include the modification of shovels. In the absence of geological information and hydrologic regimes through creation of vast tailings traditional mining concepts such as planning, all of the “beaches” and diversion of rivers. In the north of Mato capital invested in equipment was quickly lost. Even Grosso State, south of the Amazon basin, the impact miners who had previously produced 10 tonnes of caused by diversion of one river extended for more gold were facing bankruptcy. Because funding in than 30 km. Poconé and other locations is obtained outside of traditional financing systems, miners pay a high price Extraction of gold associated with primary ores (e.g. for these failed ventures, in some cases, with their sulphide associated gold, often found at depth) can be lives. far more complicated. Blasting with dynamite may be required and, if the operation is not limited to a small- Mechanization has also been important in increasing scale excavation at the surface, underground the productivity of hydraulic monitors and dredging tunnelling presents additional challenges (e.g. operations. While processing alluvial-colluvial ventilation, hauling, tunnel stability, etc). Some terraces, hydraulic mining operations frequently use operations extract gold from quartz veins, which may bulldozers and excavators to remove soil and waste contain extremely high grades (>10-20 g Au/tonne). material. At the beginning of the Amazon gold rush, Most gold is not occluded in sulfides and can be mercury was commonly spread on the ground in the extracted by amalgamation or cyanidation without belief that mercury moved throughout the dirt to prior sulfide oxidation. Experienced miners can capture all available gold. This resulted in enormous recognize that once gold associated with pyritic quartz mercury losses; in some cases up to ten parts of veins is encountered, this signifies the beginning of mercury per one part of gold produced. Hydraulic the end of their activities. Without access to technical operations usually employ riffled or carpeted sluice support, desperate miners invest in "miraculous" boxes to concentrate gold prior to amalgamation (Plate solutions to extract gold from sulfides with results 1). In some