Literatura académica sobre el tema "Small-scale miners"

This dissertation examines the role of donor-funded international projects to reduce mercury pollution from artisanal and small-scale gold mining (ASM). ASM is the second largest source of anthropogenic global mercury pollution, accounting for roughly 1000tonnes of atmospheric emissions and releases to the environment per annum. The artisanal mining economy involves 10-15 million people across the developing world, and supports 80-100 million people directly and indirectly. In 2003 the Governing Council of the United Nations Environment Program reached consensus that there is sufficient scientific evidence to trigger an international response to global mercury pollution, including the pollution generated by ASM. Yet thus far most international interventions have concentrated on environmental monitoring and assessment, while virtually no efforts have focused on implementing solutions. The aim of this dissertation is to move global mercury policy for ASM past its emphasis on assessments. It does this by developing a philosophical and strategic policy framework to guide future interventions by international institutions. A brief history of global mercury policy is provided, illustrating how ASM has been neglected and examining divisions between ecocentric and technocentric theories of environmental intervention. The relationship between ASM and poverty is examined, reaching the conclusion that because artisanal gold mining is a form of upward mobility for the world's extreme poor, the idea of reducing mercury pollution by redirecting miners into alternative livelihoods is unrealistic; indeed gold itself is the alternative livelihood. Using case studies collected in the field, the issue of conflict over property rights between artisanal miners and large-scale mining companies is explored, and a risk mitigation framework presented to assist companies to coexist with artisanal miners. Finally, a new approach to international intervention is proposed based on three interdependent principles of formalization, capitalization, and education. A plan is developed for directing more expertise and financial resources to the field, and more effectively meeting the needs of miners. Specific recommendations include a rapid assessment methodology to select project sites, and improving operational linkages among public and private institutions.

Mercury is a well-known toxic element which can be taken up into the human body in different forms, causing particular harm to the nervous system. Despite this fact, it is still used widely in industrial processes, with chlor-alkali electrolysis one of the most extensive pollution sources of mercury. Though most industries today use mercury-free processes, some chlor-alkali factories still use the mercury process, especially in less developed countries. In addition, small-scale gold mining activity remains the largest global mercury consumer and continues to increase the use of mercury given the upward trend in the price of gold. The aim of this study is to investigate the level of mercury exposure to workers in chlor-alkali factories and a dental hospital in Pakistan. In addition, it is to investigate the level of mercury exposure to miners in small-scale gold mining areas (AGM) in Cambodia, Burkina Faso and Chile. Both investigations were undertaken within the United Nations Environment Programme (management of mercury waste). Within this study, the investigation of mercury exposure to miners was conducted in four small-scale gold mining areas in Sudan. A simple analytical digestion and extraction method for total mercury (T-Hg) analysis in biological and environmental samples with fast sample preparation procedure using CV-AFS and ICP-MS was developed. In addition, for SSIDMS-GC-ICP-MS analysis, the alkaline microwave assisted extract method and acid leaching assisted extract method for Me-Hg analysis in biological samples (hair samples) were developed. These developed analytical methods were used to evaluate the levels of occupational and environmental exposure in the selected areas with Hg hot spots. For Pakistan, to establish chlor-alkali workers' Hg exposure, hair and nail samples of 23 individuals were investigated for total mercury. Within this cohort, 15 individuals had hair total mercury levels above 100 μg g-1, thus exceeding the WHO regarded "safe limit" of 2 μg g-1 in hair Hg by a factor of 50. Several samples showed hair T-Hg levels above 1000 μg g-1, suggesting extreme exposure to Hg. These levels must be regarded as extremely toxic, assuming that these Hg levels in hair correspond to Hg ingestion. In the process of chlor-alkali electrolysis, volatile mercury compounds are formed, including Hg0 and other volatile mercury compounds. These volatile species can adsorb on surfaces, and it is suggested that besides uptake by inhalation, Hg compounds may be adsorbed on keratinous hair and nail material. The investigation of single hairs with synchrotron techniques showed that most of the mercury is found on the outside of the hair, but certain amounts were also metabolised. Adsorption experiments with Hg0 and HgCl2 were conducted to assess the sorption characteristics of these volatile Hg compounds. The results showed that both mercury species' vapour pressures are related to the adsorption of volatile mercury compounds. HgCl2 has a higher vapour pressure and is about two orders of magnitude higher in adsorption than Hg0, suggesting that the chlor- alkali workers have been exposed to HgCl2 in the chlor-alkali plant. Finally, mercury speciation was performed on the ICL chlor-alkali hair samples which showed that almost all mercury was in inorganic form. The source of Me-Hg in the hair seems to be dietary, as no correlation between inorganic and Me-Hg in the hair could be found. The highest value for Me-Hg is around 5.0 μg g-1, which is in the range of concentration found in communities with a high fish diet. Finally, the high mercury result suggests that the mercury (Hg) in the hair samples from workers in the ICL chlor-alkali is from external adsorption rather than from inhalation and was subsequently incorporated into the hair. Nevertheless, in the second chlor-alkali factory in Pakistan (SCL chlor-alkali factory), the average total mercury concentrations in hair and nails are low and almost at control level. However, in this factory, mercury cell technique was phased out a few years ago. This factory now uses membrane cell instead of mercury cell technology. For the dental hospital sector in Pakistan, inorganic mercury concentrations were 6 times higher than Me-Hg concentration in hair samples i.e. Me-Hg and In-Hg in hair accounted for, on average 14.13 % and 85.87 % of T-Hg respectively for these dental workers. However, the high mercury levels in hair could be due to exposure to amalgam. For AGM areas, the T- Hg concentration (μg g-1) in hair samples from AGM miners in Burkina Faso (mean, 3.80 μg g-1) were compared with Cambodian AGM miners and Sudan AGM miners (mean 5.78 and 5.04 μg g-1 respectively). This mean value was significantly lower than that found in the hair of miners in the Cambodia and Sudan AGM areas. This indicates that the AGM miners in these countries are exposed to mercury vapour during the AGM processes. Otherwise, the AGM workers in Cambodia are also exposed to considerable amounts of methylmercury (Me-Hg) through seafood consumption that is a more toxic Hg form. However, the long-term implications for water bodies such as River Nile and Red Sea ecosystems, fish as food and irrigation water use (e.g. for rice paddies) may be disastrous. Therefore, further investigation of Hg analysis in hair and soils should be conducted in these areas to analyse the risk of Hg contamination.

Thesis (MTech (Business Administration))--Cape Peninsula University of Technology, 2016.<br>Small-scale mining entrepreneurs are confronted with a variety of challenges during both the start-up and growth phase of their businesses not only in South Africa, but all over the world. Most small-scale mining entrepreneurs are not able to take advantage of the opportunities that are available to them. This retards the growth of their businesses. The aim of this study was to investigate the challenges and prospects for small-scale mining entrepreneurs in South Africa, the support structures available to them as well as the factors that could make them successful. The research problem in this study is that the mining sector is biased towards more established companies and against small-scale mining entrepreneurial operations, which marginalises small-scale mining entrepreneurs. Despite being a significant source of revenue for South Africa, the mining sector does not directly benefit the historically disadvantaged people. Notwithstanding government interventions, small-scale mining entrepreneurs face numerous challenges during both the business start-up and growth phase of their businesses with very few prospects of succeeding. This is a qualitative study that uses a series of face-to-face interviews with mining entrepreneurs in South Africa to generate data. Given that small-scale mining entrepreneurs are in most cases part of the informal sector and difficult to locate, a database of small-scale mining entrepreneurs was obtained from Mintek. Initially, 21 small-scale mining entrepreneurs were randomly selected to participate in this study. However, it soon became apparent that ten of them were no longer in business. This meant that the sample was reduced to eleven mining entrepreneurs, located in four provinces: Free State, KZN, Mpumalanga and Limpopo. The findings of this research reveal that small-scale mining entrepreneurs are handicapped by a lack of financial and technical resources, and therefore cannot purchase capital items. It seems that there are good prospects for small-scale mining, particularly in open markets. However, they are unable to exploit these prospects because they lack the necessary finance. Although there are support structures to assist them, they find it difficult to meet the criteria for loans or overdraft facilities from financial institutions. Although these mining entrepreneurs have benefited from the support they have received thus far, they need equipment and commitment to their businesses to remain successful. A series of recommendations are made to guide small-scale mining entrepreneurs already in business, prospective small-scale mining entrepreneurs and other stakeholder’s interested in transforming the industry.<br>Zandisile Holdings (Pty) Ltd National Research Foundation Mauerberger Foundation

The general characteristics of gold deposits are reviewed, and a classification of gold deposits based on mineability is proposed. Evaluation, mlnlng and beneficiation methods are briefly discussed. It is concluded that the most viable targets for small-scale companies comprise deposits that require the least pre-production time and expense. Great potential exists for the small-scale reclamation of gold from tailings dumps and abandoned mines in Southern Africa. There is also potential for developing new smallscale gold mines in the Archaean greenstone terranes of the Zimbabwean and Kaapvaal cratons.

Um dos maiores desafios para a mineração no Novo Milênio é a integração da Pequena Mineração no sistema ativo e sustentável de exploração dos recursos minerais. A Pequena Mineração (PM) é uma atividade de mineração definida por baixas despesas e receitas de capital e baixa produtividade. A Mineração Artesanal (MA) é apenas um subconjunto de PM, caracterizada pela mecanização rudimentar, recuperação ineficiente, condições operacionais inseguras e exploração do trabalho. Essa tese pretende demonstrar as seguintes questões de pesquisa: 1) A PM pode ser sustentável? 2) Se sim, como pode ser avaliada? 3) Como a PM sustentável pode ser conseguida na prática? Ao longo da tese é mostrado como a PM pode ser sustentável só saindo da dimensão artesanal. Tal processo depende da sua própria capacidade para operar de forma eficiente. Quando a eficiência operacional é alcançada, a sustentabilidade vem como consequência. Através da eficiência operacional, uma operação de SSM sai da condição artesanal, torna-se sustentável e a sustentabilidade dos meios de subsistência e ambiente circundante é estritamente consequente. Esta tese aborda a questão da PM, de forma quantitativa e não qualitativa. Indicadores básicos são individualizados especificamente para medir as características peculiares de minas artesanais, que as diferenciam das minas industriais. O objetivo desses indicadores é a padronização da avaliação de mina artesanal em termos quantitativos, uma importante ferramenta de pesquisa que não era disponível até agora. A análise desses indicadores permite medir a sustentabilidade potencial de uma mina artesanal, bem como sua atualização ao longo da transformação em uma pequena unidade de mineração industrial. Propõe-se uma nova abordagem para a gestão dos recursos minerais e reservas especificamente para a mineração em pequena escala, a fim de atualizar as minas artesanais em pequenas minas industriais. A abordagem proposta para o cálculo dessa reserva contém dois conceitos principais: uma \"reserva mínima\" necessária para o início do projeto, e a \"replicação\" da operação. A metodologia proposta, aplicada a uma operação de mineração subterrânea de ouro real, mostrou que, no caso em análise, as reservas necessárias para viabilizar a operação de pequena escala são da ordem de grandeza de 1/1000 de que as necessárias para a mineração em grande escala. Este trabalho mostra como uma forma responsável e sustentável de PM é possível e viável, ajudando o desenvolvimento econômico da região onde atua, e criando externalidades positivas, como educação, capacitação, cultura da eficiência e consciência ambiental.<br>One of the biggest challenges for Mining in the New Millennium is the integration of small-scale mining in the active and sustainable system of exploitation of mineral resources. Small-Scale Mining (SSM) is a mining activity defined by low productivity low capital expenditure and revenues. Artisanal Mining (AM) is just a subset of SSM, characterized by rudimentary mechanization, inefficient recovery, unsafe working conditions and labor exploitation. This thesis intends to answer the following research questions: 1) Can SSM can be sustainable? 2) If so, how can it be evaluated as such? 3) How can sustainable SSM be put into practice? Along the thesis is shown how SSM can be sustainable only coming out of the artisanal dimension. Such a process depends on its own ability to operate efficiently. When operational efficiency is achieved, sustainability comes as a consequence. Through operational efficiency, an operation of SSM comes out of the artisanal condition, it becomes sustainable, and sustainability of surrounding livelihood and environment is strictly consequent. This thesis approaches the issue of SSM in a quantitative and not qualitative way. Basic indicators are individuated specifically to measure the peculiar characteristics of artisanal mines, which differentiate the latter from industrial mines. The purpose of these indicators is the standardization of artisanal mine evaluation on a quantitative basis, an important yet currently unavailable research tool. The analysis of such indicators enables the potential sustainability of an underground artisanal mine to be measured, as well as its upgrade over time towards classification as an industrial small-scale mining unit. It is proposed a new approach for the management of mineral resources and reserves specifically for small-scale mining, in order to upgrade artisanal mines into small-scale industrial mines. The proposed approach to calculate this reserve contains two main concepts: a minimum reserve required for the project start-up and replication to confirm the feasibility of continued operation. The proposed methodology, applied to an actual underground gold mining operation, proved that, in the case analyzed, the reserves required for the small-scale operation are in the order of magnitude of 1/1000 of that required for large-scale mining, when both businesses possess the same level of feasibility. This work shows how a responsible and sustainable form of SSM is possible, achievable and viable, helping the economical development of the area where it operates, and creating positive externalities such as education, capacity building, culture of efficiency and environmental awareness.

Thesis(MTech (Chem.Eng.Technology))--//Cape Technikon, 1999<br>The gold mining industry has mainly relied upon the use of a highly polluting chemicals, such as mercury and cyanide, to recover gold from its ores. As environmental legislation has become more stringent in all countries and environmental protection has become the focus of world-wide research, development of environmental sound processes has been favoured. The Coal Gold Agglomeration (CGA) process is such a process which was developed some years ago and has the advantage in that gold is recovered by a procedure which has little or no effect on the environment. The CGA process is based on the hydrophobic characteristics of coal, gold and oil. Gold particles which are substantially free become attached to the coal-oil agglomerates during collision, and eventually penetrate into the agglomerates. The resulting agglomerates are recycled to increase the gold loading, separated from the slurry, burnt, ashed and smelted to produce gold bullion. Laboratory scale batch tests were performed on an artificial/synthetic gold ore, containing fine gold powder. The slurry was contacted with a mixture of coal and oil. i.e. coal-oil agglomerates, after which both the agglomerates and ore were analysed for gold. Operating parameters, such as the mode of contact between the coal-oil phase and the gold containing slurry, contact time of the slurry and the coal-oil phase, means of separating the coal-oil gold agglomerates from the slurry, coal to ore, coal to oil and water to ore ratios, type of oil, effect of collectors and the mineralogy of the ore on the gold recovery were investigated. Results have shown that stirring the coal-oil phase and the slug yielded higher gold loadings than shaking and the traditional rolling bottle technique. BI increasing the time of contact between the coal-oil phase and the gold slurry. the final gold loading in the agglomerates increases, until an equilibrium value is reached. An increase in the amount of coal, together with a decrease in the amount of water used in the slurry, has shown to increase gold recoveries. Furthermore, by varying the concentration and volume of a collector. such as potassium amyl xanthate (PAX) enhanced the settling rate and enabled the effectiveness of separation. Moreover, it was found that the gold loading on the coal-oil phase increased after recycling it. Further tests were performed on a real ore sample and after X-ray Diffraction (XRD) analysis, it was found that certain minerals other than gold was transferred to the coal-oil phase. The theoretical foundation of the CGA process is based on the difference in free energy and was expressed as a function of the interfacial tensions and three-phase contact angles between gold, oil and water, together with the ratio of coal-oil agglomerate to gold particle radii, as the free energy is a measure of the thermodynamic stability and hence, partly a measure of gold recoveries, meaningful predictions as to gold recoveries were made by performing a sensitivity analysis on the variables connected to the free energy, It was, however, found that some operating parameters, which were linked to other factors, such as the maximum gold transfer into coal-oil phase and the separation efficiency of the agglomerates. were vital to be taken into account when predictions as to gold recoveries were made. Therefore, the gold recoveries were found to be a function of the thermodynamic stability as well as the maximum gold transfer into the coal-oil phase and the separation efficiency of the agglomerates, The meaningful information gained by performing the theoretical investigations were applied and linked to gold recoveries, thereby providing useful explanations as to the typical gold recoveries obtained during experimentation. A comparative study on mercury amalgamation was done to evaluate the performance of the CGA process. It was found that the CGA process yielded better gold recoveries than amalgamation, which makes it the better process both in terms of recoveries as well as environmental safety, A further application of the theoretical knowledge was, however, very useful to explain the tendency of the CGA process yielding the better results.

The current weak state of the platinum market, as well as the large inventory of platinum group metals held by Russia, necessitates that the South African platinum mining industry must carefully evaluate the benefits and disadvantage of small-scale mining of shallow, open castable ore resources. Until the late 1980's, these resources were ignored due to the metallurgical complexities of treating oxidized ore, as well as the mind set that existed within the South African mining industry which militated against open cast mining in the Bushveld. During the latter part of the 1980's and early 1990's, advances in the metallurgical treatment of oxidized ore, specifically the UG2, as well as operational problems, created the impetus to begin the exploitation of these resources. Small-scale open cast mining has become viable due to the development of suitable mining methods that facilitate mining practices acceptable to the Department of Mineral and Energy Affairs, in terms of environmental legislation. Metallurgical advances and growing experience, especially with respect to the UG2, enables reasonable platinum group metals recovery from oxidized ore. The problems experienced in doing this can, and are being overcome. With growing public awareness of environmental issues, particularly related to the mining industry, the requirement to ensure that the small-scale open cast mine site is well managed is paramount. A methodology for the evaluation is presented along with a case study of a small-scale UG2 open cast pit. Evidence is presented that shows that these small-scale open cast mining operations are extremely profitable and require minimal capital expenditure. However, caution is advised when evaluating Merensky Reef open cast operations because of the problems that they present.

In considering how women navigate the complexity and gendered aspects of the artisanal mining industry, this study seeks to unpack women's labour at step one of the global supply chain of coltan, in the post-conflict context of eastern Democratic Republic of Congo (DRC). Female miners are largely excluded from mine work by blurry regulatory frameworks, gendered social norms and financial disparities, however they manage to remain active labourers in the artisanal mining industry. Within a broader socio-political context of poverty, political instability and rural livelihoods, women maintain access to mine work through strategies, often premised on a gendered solidarity, such as organizing into collectives, engaging in small group collaborations and employing creative ruses to maintain the secrecy of their labour. This thesis seeks to analyze women's exclusions from mine work and the subsequent strategies they employ to circumvent those exclusions and maintain work in the mines. Based on three months of ethnographic fieldwork at artisanal coltan mine sites in Masisi Territory in the province of North Kivu, this study employs ethnographic observations, focus group and interview methodologies.