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1
Bouwer, Wendy. "An environmentally sound gold recovery process for small-scale gold mining." Thesis, Cape Technikon, 1999. http://hdl.handle.net/20.500.11838/869.
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Thesis(MTech (Chem.Eng.Technology))--//Cape Technikon, 1999The 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.
2
Siegel, Shefa. "The needs of miners: political ethics, mercury abatement, and intervention in artisanal gold mining communities." Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/435.
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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.
3
Tran, Dung Trung. "Gold-containing bimetallicnanoparticles." Thesis, University of Birmingham, 2011. http://etheses.bham.ac.uk//id/eprint/1362/.
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This thesis describes computational studies, syntheses and characterization of Cu-Au, Pd-Au, and Pt-Au bimetallic nanoparticles. The computational methodology is a combination of a genetic algorithm coupled with an empirical potential and density functional theory, which is used to study theoretically the geometrical structure, chemical configuration, and electronic properties of 38 atom Cu-Au and 40-atom Pt-Au nanoparticles. Experimental Cu Au and Pt-Au nanoparticles are synthesized by wet-chemical methods: the two-phase method combined with a galvanic exchange procedure (dodecanethiol-stabilized Cu-Au nanoparticles), the polyol method (Polyvinylpyrrolidone stabilized Pt-Au nanoparticles), and the Turkevich-Frens method combined with a successive reduction procedure (citrate-stabilized Pt-Au nanoparticles). The Pd-Au nanoparticles which are characterized in our work were synthesized by a microbial method. The nanoparticles are characterized using transmission electron microscopy (TEM) and scanning TEM (STEM) combined with high angle annular dark field (HAADF) imaging, energy dispersive X-ray elemental mapping using a silicon drift detector (SDD), tomography, and electron energy loss spectroscopy (EELS). Sizes and shapes of the Cu-Au, Pd-Au, and Pt-Au nanoparticles are studied by TEM. Morphological evolution and aggregation of the Cu-Au nanoparticles are also observed under the TEM electron beam. SDD-EDX elemental mapping combined with HAADF contrast is used to study the chemical configuration of all the three systems. HAADF-STEM tomography is performed for the Pd-Au nanoparticles. Surface plasmon resonances of the Cu-Au and Pd-Au nanoparticles are studied using EELS. The structures and configurations of the theoretical bimetallic clusters and the experimental bimetallic nanoparticles are found to be composition-dependent.
4
Morse, Kathryn Taylor. "The nature of gold : an environmental history of the Alaska/Yukon gold rush /." Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/10468.
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Mather, Diarmid John. "An approach to analyzing gold supply from the South African gold mines." Thesis, Rhodes University, 1995. http://hdl.handle.net/10962/d1002750.
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The gold mining fIrm in South Africa is viewed as a normal fIrm producing gold bearing ore but faced with a quality constraint (grade). Grade, however, is never uniformly distributed in a metalliferous deposit and because high grades are mined fIrst, the quality constraint becomes increasingly severe with cumulated production. The fIrm will continue to mine gold bearing ore until it reaches its mining limit where the marginal cost of recovering the gold is equal to the marginal revenue received from that gold and at that point the economic deposit becomes exhausted. Because the mining limit is determined by cost/technology and price, it is not fIxed and thus the point of economic exhaustion may change. When high grades are mined fIrst the relationship between the tonnage of gold ore and the grade describes the rate at which the grade is expected to fall with cumulated production. In this thesis, the grade for South African Witwatersrand gold producers is modelled to fall exponentially. The mining limit, determined by costs/technology and price, can be expressed in terms of grade. By predicting the decay in grade relative to the tonnage of gold ore and applying a mining limit, a life-time size of the economic deposit can be estimated. The remaining life of a producing gold mine can then be determined and the flow of gold predicted. An empirical treatment using the disk model of a gold deposit is undertaken for a gold mine, a goldfIeld and the total Witwatersrand gold deposit. A dynamic econometric analysis of expected mining costs and gold prices is not attempted; however certain examples are used to illustrate the applicability of the model and the influence of the South African gold mining tax formula on the life of the mine.
6
Joubert, Barend Daniel. "Small-scale gold mining in southern Africa." Thesis, Rhodes University, 1992. http://hdl.handle.net/10962/d1005615.
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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.
7
Ackley, Mary. "Evaluating Environmental Risks in Mining: a Perceptual Study." ScholarWorks @ UVM, 2008. http://scholarworks.uvm.edu/graddis/7.
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Gold mining is often associated with positive economic benefits; however, it may also have negative impacts on the environment and human health. It is essential that communities understand the risks and benefits associated with mining, particularly in developing countries where there is often a lack of legislation governing the environmental performance of mining corporations. The perceptions of local people regarding the risks and benefits of mining may differ significantly from those of company representatives, policy makers, and the scientific community. Indeed, public concerns have sometimes been ignored or downplayed by those responsible for the implementation of environmental policies and practices. Examination of the complex social, economic, psychological, political, and cultural factors influencing risk perception in mining communities is thus important for successful risk communication and management. Issues arising from the interplay between socio-economic benefits and risks are particularly acute in small island states which have isola ted and highly limited economic development trajectories. The lessons learned in such cases are therefore instructive for crisis planning across the developing world. This study conducted firsthand empirical research into the perception of environmental and health risks in the communities surrounding the Vatukoula gold mine in Fiji. Primary data was obtained through a survey questionnaire designed to quantify and evaluate perceived risks (n= 340, representing approximately 24% of the target population). Concurrently, environmental samples were collected to assess the extent of environmental impacts at the study site. Study results revealed that gender is an important variable in risk perception at Vatukoula. Major findings include: (1) women feel they have less knowledge about the risks of mining compared to men; (2) women feel they have less control to avoid the risks of mining compared to men; and (3) women and men tend to receive risk messages from different sources. The information obtained during this study was made directly available to local stakeholders, to aid in risk management and decision-making.
8
Mann, P. L. "Surficial placer gold deposits." Thesis, Rhodes University, 1994. http://hdl.handle.net/10962/d1018245.
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This review summarises the factors which control the formation and distribution of surficial gold placer deposits. Regional tectonic and climatic conditions as well as gold source are considered. The characteristics of eluvial, alluvial, marine, glacial and fluvioglacial gold placer deposits are described. Particular attention is paid to the gold grains within these placers. These gold grains have a distinctive morphology and chemical composition which reflect the manner in which they were transported, deposited and concentrated within the placers. The knowledge of the processes which lead to the formation and location of surficial gold placers is then used to guide exploration and target potential deposits, which can then be evaluated.
9
Vermeulen, Nicolaas Johannes. "The composition and state of gold tailings." Pretoria : [s.n.], 2006. http://upetd.up.ac.za/thesis/available/etd-03102006-122937/.
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Xiao, Jie 1964. "Testing a new gold centrifugal concentrator." Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=20932.
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A new gold centrifugal concentrator, the Falcon SuperBowl, was tested both at plant and laboratory scales to assess its ability to recover gold from grinding circuits.The performances of a 21-in SuperBowl (SB21) at Mineral Hill and New Britannia Mines showed that it could recover gravity recoverable gold (GRG) of all sizes, especially below 25 mum at Mineral Hill Mine.
Three types (to test the effect of gangue density and size distribution) of synthetic feeds were used to characterize a laboratory 4-in SuperBowl (SB4) as a function of feed rate and fluidization water flow rate.
A 20-in Knelson Concentrator and a shaking table were further tested in this program with the samples extracted from Casa Berardi and Mineral Hill Mine, respectively. The 30-in Knelson was tested at two different conditions to assess the impact of fluidization water flow rate and explore the importance of cycle time. (Abstract shortened by UMI.)
11
Davidson, Raymond John. "Innovations in gold extraction." Thesis, Rhodes University, 1993. http://hdl.handle.net/10962/d1004975.
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The thesis takes the form of a collection of publications and patents concerning gold extraction which were presented over a period of 18 years while employed at the Anglo American Research Laboratories.
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Rankine, Graham M. "Gold metallogeny of Australia." Thesis, Rhodes University, 1987. http://hdl.handle.net/10962/d1004676.
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The gold metallogeny of Australia is predominantly confined to the Archaean and Palaeozoic Provinces. The Archaean gold occurrences are predominantly hosted in ultramafic-mafic dominated greenstone belts, with less associated tofelsic-volcanic and sedimentary sequences. Most gold occurrences are confined to shear zones or faults, and adjacent discoveries of economic laterite-hosted deposits, host rocks. Recent are presently under investigation and will supply a significant proportion of production in the future. The Proterozoic gold deposits of Australia , are confined to geosyncinal sequences, commonly turbidites (eg: Telfer), with other hydrothermal deposits associated directly to granites. An important feature of the North Australian Craton deposits, is the spatial association of most deposits to granite bodies, although a genetic link has not been established conclusively. The Roxby Downs deposit in South Australia is a unique occurrence of gold in association to copper, uranium and R.E.E. This deposit is tentatively related to intraplate alkaline-magmatism, with further work necessary. The most significant recent discovery of gold mineralization in Australia is in the Drummond Basin in Queensland. This epithermal is tentatively related to mineralization within the Georgetown Inlier. The latter mineralization is Permo-Carboniferous, in a Proterozoic (and possibly Archaean) sequence of schists. It is tentatively suggested that all the gold mineralization in northern Queensland may be related to single tectonic event, a feature which requires further study . Other mineralization in the Phanerozoic includes the turbidite-hosted metamorphogenic deposits of Victoria, the rift related deposits in New South Wales and magmatic related deposits in Queensland. The gold deposits in Australia may in the future be classified in a tectonogeological framework, similiar to the layout of this dissertation, particularly once further data becomes available on recent discoveries.
13
Delos, Reyes Julie Ann. "Mining shareholder value : financialisation, extraction and the geography of gold mining." Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/mining-shareholder-value-financialisation-extraction-and-the-geography-of-gold-mining(d1f1b04a-1cd4-4577-b2ca-c44cc39f7583).html.
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This thesis examines the influence of institutional investors in the activities of large, publicly traded gold mining companies. As key sources of financing and dominant shareholders in company stocks, institutional investors have pushed for the maximisation of shareholder value as company goal. I examine the financial and operational realignments implemented by firms and their implications for production, growth and geography in the commodity boom and bust cycle of 2003-2015. I argue that the bid to deliver shareholder value manifested in highly fragmented, but interlinked, sites of accumulation: sharp swings in stocks and dividend payments that diverged from their actual basis in production, alongside increasing claims to future profitability through spatial restructuring. I theorise the process as contradictory-laden and crisis-prone as mineral extraction came to be mediated by the yield requirements, investment motives and risk tolerance of institutional investors. The thesis contributes to key debates on financialisation and mineral extraction within geography, political ecology and the financialisation literature.
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Raymond, Luke M. "Gold and Base Metal Mineralization of the Dolphin Intrusion-related Gold Deposit, Fairbanks Mining District, Alaska." Thesis, University of Alaska Fairbanks, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10929098.
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The Dolphin deposit is an intrusion-related gold deposit (IRGD) located approximately 30 km north of Fairbanks, Alaska. The deposit is in--and adjacent to--a composite mid-Cretaceous pluton intruding amphibolite facies metamorphic rocks. NI43-101 compliant gold resource estimations for the deposit utilizing a 0.3 g/t cut-off, is 61.5 Million tonnes (Mt) at 0.69 g/t indicated (1.36 million oz = Moz) and 71.5 Mt at 0.69 g/t inferred (1.58 Moz).
Due to extensive hydrothermal alteration of the intrusion, identifying lithology in hand sample and thin section, as well as by standard compositional techniques (SiO2 vs. Na2O + K2O), has proven problematic. By plotting wt% TiO2 vs. P2O5 obtained from XRF analysis and four-acid digest ICP-MS data, two distinct population clusters appear. By comparison with least-altered intrusive rock analyses from the Fairbanks district, the igneous units can be identified as granite and tonalite. Because there is no gradational transition through an intermediate granodiorite unit, they were most likely derived from two separate magmatic bodies rather than in-situ fractionation from a single parent. Tonalite is concentrated along the northern and eastern margins of the stock with granite composing the rest of the body. Tonalite xenoliths in granite and granite dikes intruding tonalite prove that tonalite is the older unit.
Investigations of hydrothermal alteration (based on chemical analyses, X-ray diffraction, and thin section examination) show albitic and advanced argillic (kaolinite-quartz) alteration are the dominant styles with sericite common throughout. Advanced argillic is a low temperature (<300°C) low pH alteration style that has not been previously identified in intrusion related gold deposits (IRGDs) in interior Alaska. Albitic alteration resulted from higher temperature, more neutral pH fluids.
Gold investigations show that gold occurs as coarse-grained Au°, aurostibite, and maldonite in quartz + sulfide veins; fine-grained Au° in the oxide zone; and in many forms in disseminated sulfide. These forms include Au° inclusions in pyrite and arsenopyrite, solid-solution Au within compositionally zoned arsenopyrite, and as Au° nanoparticles in pyrite and arsenopyrite. Using UAF’s JEOL JXA-8530F microprobe, I found that solid-solution gold occurs only in arsenopyrite with strong compositional zoning. These have low As cores; gold-bearing mantles with moderate % As; and high As rims. In contrast, compositionally homogenous arsenopyrite does not contain solid-solution gold. Pyrite is commonly arsenian and carries dissolved gold (if any) near detection limits. Gold mineralization has not been tied to any lithology or alteration style; however, gold does seem to correlate with abrupt changes in alteration, especially between sericite + albite and kaolinite + sericite alteration and gold-bearing, zoned arsenopyrites are associated with advanced argillic alteration.
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Seitkan, Ainur. "Environmental mineralogy of gold recovery from refractory gold-arsenic-bearing Bakyrchik concentrates." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/273373.
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Arsenic contamination of groundwater associated with mining operations is a widespread problem across the globe. The release of arsenic (As) into the environment occurs naturally by oxidation of exposed sulfide minerals. In the case of gold ores, the mining and beneficiation may also produce As-bearing wastes and this can accelerate the natural mechanisms of As mobilization. The Bakyrchik is the largest gold deposit in Kazakhstan and one of the largest in the world. Gold (Au) is dispersed in pyrite and arsenopyrite in the form of microscopic inclusions. Despite the fact that only 10% of gold ore has been mined to date, it has left behind a dangerous As-containing legacy. Speciation of As has been determined for samples from Bakyrchik to understand the post-processing environment and the mobility of arsenic in the mining-influenced area. As(III) and As(V) have been detected in water samples using HPLC-ICP-MS. The variability of As species across the narrow pH and Eh range indicates that biogeochemical processes can play a role in the speciation of As in water at the study site. In order to understand processes controlling As mobilization in water, the solid phase speciation of As in Bakyrchik sediments, soil, and metallurgical processing products has been investigated using XRD and EPMA. This revealed arsenopyrite, As-bearing pyrite, and their alteration products containing up to 25% As, iron oxides and oxyhydroxides (with up to 2.5% As), haidingerite, and calcium arsenate in studied samples. Sequential extraction demonstrated that in soil and sediment samples As is associated mainly with Al and amorphous Fe oxyhydroxides. Results suggest that the main mechanisms controlling As mobility in Bakyrchik are dilution with regional waters, adsorption onto iron and aluminium oxyhydroxides, and co-precipitation of dissolved As with alteration products of sulfide minerals. Assessment of As bioaccessibility through inhalation demonstrates its strong dependence on the mineralogy rather than on total As content of the solid samples. Calculated cancer and non-cancer risks of inhalation exposure imply that all samples are highly hazardous for human health. With the depletion of the oxide lode ore deposits, gold extraction is moving towards the mining of technologically difficult ores, such as those found at Bakyrchik. A new method of Au recovery from double refractory Au-As-bearing concentrates has been developed, allowing recovery of 97% of Au, and the conversion of up to 95% As into iron-arsenic alloy. Fe-As alloy can contain up to 40% As, and do not require further solidification/stabilisation prior to disposal. The method has been published as a patent with the Patent Office of the Republic of Kazakhstan. Quantitative phase composition of the Fe-As alloy, has been determined by EPMA, QEMSCAN, X-ray and neutron diffraction. Toxicity and solubility of Fe-As alloy in aqueous solutions have been characterised. High-temperature structural behaviour of Fe-As alloy and Fe$_{2}$As in inert atmosphere has been determined by $\textit{in situ}$ synchrotron XRD. Results of the study support the development of the new method as an efficient alternative for processing double refractory Au-As-bearing concentrates.
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Miller, Mark Henry Bruce. "The optimum communications architecture for deep level gold mining." Diss., Pretoria : [s.n.], 2000. http://upetd.up.ac.za/thesis/available/etd-01122007-124105/.
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Zampa, Greta. "Possible effects of gold mining on coral reef health." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/17426/.
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Indonesia, being the core of the Coral Triangle, is supposed to hosts the most healthy and diverse coral reefs on the Planet Earth. However, the combination of global and local stressors has led to a decline in coral reef communities around the world. Anthropic activities of particular interest in North Sulawesi are industrial and artisanal gold mining (ASGMs). Industrial mining activities generally used the alkaline cyanidation method while ASGMs still employ mercury amalgamation to extract gold from ores. The extraction and processing of gold produces mine tailings that contain heavy metals, which may be dispersed in the catchment basin due to rain and flooding events and could alter the natural defences of the corals and favour the onset of diseases. The objective of this study was to assess the possible impacts of gold mines in North Sulawesi on coral reef health by comparing prevalence of coral diseases and aggressive species interactions between putatively affected and control sites. As putatively impacted sites, coral reefs downstream to four mining sites were selected: one long-time and one recently established ASGM, a modern industrial mine and a new site in preparation.
Among the 21 possible diseases and other signs of compromised health investigated, gastropod corallivory, aggressive overgrowth, skeletal deformations caused by pyrgomatid barnacle and bleaching, were significantly more abundant at some sites affected by mining activities, compared to controls. A significant increasing of coral bleaching appeared as a result of the pollution generated by ASGMs, which release mercury in the aquatic environment. Detected alterations indicate that long term mining activities can affect the health of coral reefs. Mining in the area is expected to increase due to the large availability of resources, but well environment-based policies are needed to ensure that this development does not compromise biodiversity and marine resources.
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Tucker, Christopher L. "Business solutions to the formalization of artisanal gold mining." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/56231.
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Artisanal and Small-scale Mining (ASM) exists in virtually every developing country with accessible mineral deposits. Typically ASM is an informal or in some cases illegal activity with numerous problems associated with it including mercury pollution, non-existent health and safety standards and abusive child labour practices. Furthermore ASM is often regulated to a “subsistence” activity that, along with poor financial management among the miners, keeps participants trapped in a cycle of poverty. Nonetheless, ASM is remarkably productive and has the potential to be extremely profitable as well as environmentally and socially responsible given guidance and formalization. Efforts to formalize ASM activity thus far have been government-led, top-down, heavy-handed attempts to police an activity that employs an estimated 20-30 million people world-wide, often in remote places and often in situations where they believe they have no economic alternative for survival. Not surprisingly, these efforts have met with limited success. The productive and potentially very profitable nature of this activity, where there is no shortage of demand for their extremely fungible product, lends itself readily to a business approach. Franchise businesses are effective in markets where consistency in operations and production are required, especially where such operations are attractive to capable local operators. The franchise model offers access to finance, improved technical capacity for increased recovery, business management expertise, access to banking and personal financial guidance, and a mechanism to reduce environmental and social risk. Furthermore, investors are increasingly wary of investing in junior mining companies as country-risk, resource nationalism, and social license to operate act as impediments to a project’s timely entry to production. ASM offers high social license with local operators and well-diversified country risk. Thus, a small-scale gold mining franchise offers an appealing opportunity to manage, as well as diversify against, such risk factors, while remaining in an extremely profitable and hitherto unexplored market. The reality in many places in Latin America is that partnerships with community locals have a much higher success rate than businesses without. Even nationals from other localities experience difficulties such as additional or longer permitting and harassment. This dynamic provides additional advantages to franchise structures.Applied Science, Faculty of
Mining Engineering, Keevil Institute of
Graduate
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Santos, Gustavo Angeloci. "Myths and realities in artisanal gold mining mercury contamination." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/44361.
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The world faces a major gold rush currently. Worldwide 15 million people work directly in artisanal gold mining in more than 55 countries. The usual method of extraction is amalgamation and cyanidation, or very commonly a combination of both. Significant amounts of contaminants are released to rivers and soil, generating environmental and health concerns. The majority of artisanal miners are involved in micro-mining, but it is believed that the majority of contamination comes from small to large artisanal operations. Larger operations involve less people, but process much more material, re-leasing much more contaminants as well.
The present work explains how contamination is generated, through a com-prehensive analysis of the labor division in small-scale mining sites around the world, and also analyses aspects of different intervention approaches.
Different approaches are taken by different groups working on the problem around the world. This work evaluates the most common kinds of interven-tion, with special attention to technical and legal aspects in trying to eliminate mercury use in gold extraction. The study is conducted by comparing differ-ent interventions strategies to evaluate the myths and realities from an engineering perspective. Special attention is paid to the evaluation of alterna-tives to amalgamation process for gold such as intensive cyanidation, borax direct smelting and chlorination. Accordingly to the location in which the technology is introduced, different methods can be applied, but only cyanide remains a proven method to deal with complex ores.
Important aspects such as education, training, financial aid and understand-ing of a community before intervention are also shown to be essential for success.
The association of Small-scale Gold Mining and potential gold concentrate consumers is pointed to as a possible solution, applicable where concentrates can be shipped to a smelter. Association with large companies is cited as an alternative means to reduce contaminants generated by gold extraction as well.
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Kuma, Jerry S. "Environmental hydrogeology of the Tarkwa gold mining district, Ghana." Thesis, University of Newcastle Upon Tyne, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.394569.
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Hamilton, James F. "A study of the fine gold recovery of selected sluicebox configurations." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/28384.
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The recovery of placer gold from 20 mesh to 150 mesh in common sluicebox configurations was investigated. Two types of riffles, 1-10H expanded metal (1.5"x.75"x.25") and 1.25" angle iron riffles (dredge riffles), were used in conjunction with 3/8" thick "Nomad" matting for 25 tests. The effects of variations in upper feed size, water flow rate, sluice gradient, and solids feed rate on the recovery of placer gold particles are documented.
The gold and test gravel were obtained from the Teck Corporation sluicing operation on Sulphur Creek, Yukon Territory during July, 1985. Approximately nine troy ounces of placer gold and fifteen tons of gravel were transported to Vancouver.B.C. A test sluice facility was constructed in Coquitlam,B.C. to simulate operating conditions in a typical Yukon placer operation. The sluicebox was 12" wide and 8' long with clear plexiglass sidewalls. Screened gravel of either 3/4" or 1/4" upper feed size was fed to this sluice from a hopper at rates of up to 1260 lb/min. The water pumping capacity was a maximum of 400 USGPM. Between 75 and 90 grams of each of three sizes of placer gold (-20+28#, -35+48#, -65+100# ) were premixed with the gravel for most tests. The final test used 25 grams of -100+150 mesh gold.
Sluicing, when properly controlled, was found to be a highly effective means of concentrating placer gold as small as 150 mesh. Expanded metal riffles were far superior to dredge riffles in concentrating gold of this size range. Recovery of the -65+100# size fraction frequently exceeded 90% when using expanded metal riffles. Visual observation of eddies formed downstream of the riffles showed that scour depth between riffles was the one characteristic of the slurry flow that gave the best indication of the resulting gold recovery. For expanded metal, scour depths between 1/2 and 3/4 of the riffle depth were found the most effective.Applied Science, Faculty of
Mining Engineering, Keevil Institute of
Graduate
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Pelly, Frederick Douglas Peter. "Guidelines to the evaluation of selectively mined, open pit gold deposits during the exploration stage of mine creation." Thesis, Rhodes University, 1992. http://hdl.handle.net/10962/d1005582.
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This dissertation studies the evaluation of selectively mined, open pit gold deposits during the exploration stage of the mine's life. Since 1970 a large number of selectively mined, open pit gold mines have come into operation. The most common deposits include epithermal vein, mesothermal lode and laterite gold deposits. In general the deposits are characterized by small tonnages (1-20 million tonnes), relatively high grades (2-10 grams per tonne gold), submicroscopic to coarse gold, inexpensive mining, and both free milling and refractory ores.The key components that require evaluating during the exploration period are the deposit's geology, ore reserves, pit design, ore metallurgy and environmental impact. Feasibility studies are the main vehicle by which to report and guide the exploration programme. During the exploration period a company may undertake an initial (geological feasibility), second (preliminary mine feasibility) and third (final feasibility) delineation programme in order to gather sufficient data to justify a mine development decision. The responsibility of evaluating the mineral prospect lies primarily with the exploration geologist and mining engineer. Broad experience, a professional attitude, a thorough understanding of mining economics, and a high level of geological, engineering and technical skills are traits required by the evaluators. In order for mining companies to make sound investment decisions the geographical, geological, mining, metallurgical, environmental, marketing, political and financial aspects affecting the economic potential of the venture must be integrated so that the likely costs, risks and returns of the investment alternative are quantified. Ultimately, it is the economic analysis of these three items that determine whether the mineral prospect is developed into a mine I delineated further I retained until economic circumstances improve, or abandoned. To assess the costs, risks and returns, extensive use of the risk analysis is advocated throughout the exploration period . When combined with intelligent judgement of the intangible risk elements, the probabilistic distribution of discounted cash flows are invaluable in making sound investment decisions. However, the economic analysis is only as good as the information on which it is founded. Accurate and representative field data is the most important prerequisite to successfully evaluating and developing a new mine.
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Moretti, Daniele. "Nkota Wata : mining and metaphor in Hamtai-Anga "Gold Dreaming"." Thesis, Brunel University, 2006. http://bura.brunel.ac.uk/handle/2438/5328.
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This work examines a series of mining-related dream narratives as a means of gauging how a community of New Guinean artisanal and small-scale gold miners understands the nature of minerals and their place in the cosmos, and how this cosmological outlook informs the ways they operate qua resource extractors. Through a "structural-metaphorical" analysis of the symbolic themes and ethnographic context of Hamtai-Anga "gold dreaming, " my thesis demonstrates that the miners of Kaindi conceptualise resource extraction in terms of a set of collaborative, procreative, and nurturing relations of "marriage" and of "affinity" between themselves, their spirit familiars, and the masalai (or guardian spirits) of the mines. According to this complex "holography of meaning", the miners are able to "generate”, “exercise, " and "make apparent" their extractive efficacy through a relational and elicitive engagement with their gendered "other"- or, in other words, by means of their capacity to make their female spirit familiars "fall in love" with them, "procreate" minerals like women procreate children, procure gold as wives provide garden food, and link them to the spirits of the mines as women link men to their in-laws. In order to secure and maintain their elicitive power, however, the miners must "enact" this metaphor by "behaving like" "good husbands" and "good affines" towards their familiars and the spirits of the mines. In turn, this means that the tropic conceptualisation of mining as conjugality and affinity with the masalai\familiars is a recipe for action imbued with its own intrinsic morality. This morality, moreover, is itself of an essentially holographic nature. Indeed, not only does it entail analogous normative structures at different "orders" of scale (that is both at the "microcosmic" "level" of interaction between the miners and their human spouses and affines, and in the "macrocosmic" plane of exchange between humans, spirit familiars, and spirits of the mines) but, as is revealed in my thesis, the two "orders" at which it unfolds are actually part of a single whole, so that the flow of analogy at the "macrocosmic" "level" has crucial implications for its "microcosmic" counter-flow, and vice-versa.
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Kalamandeen, Michelle. "Forest loss dynamics and impacts from gold mining in Amazonia." Thesis, University of Leeds, 2019. http://etheses.whiterose.ac.uk/22904/.
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Amazonian rainforests are home to Earth's largest reservoir of biodiversity, providing crucial ecosystem services and storing approximately 17% of all global terrestrial carbon. Today, these forests are experiencing rapid, unprecedented changes due to climate impacts and anthropogenic disturbances. In recent decades, the region has experienced marked variability in deforestation, and after a long period of increase, the deforestation rates in countries like Brazil have sharply declined in recent years. However, little is known about the forest trends and the impact of different drivers in other Amazonian countries. The aim of this thesis, therefore, is to better understand and examine the current dynamics of forest loss across Amazonia and how intensive land uses such as gold mining influence forest loss, nutrient cycling and recovery patterns. Using remote sensing coupled with field observations, this research highlights new spatial patterns in Amazonian forest loss which point to a more complex pattern where new smaller-scale drivers of forest loss are becoming progressively more important (Chapter 2). The expansion of small-scale events were primarily driven by gold mining activities, particularly in northern Amazonia, with underestimation of forest loss occurring at sites driven by a mosaic of small-scale clearings (Chapter 3). Nutrient depletion was found to be the most important factor driving low biomass recovery in previously mined areas, with mercury contamination being of secondary importance (Chapters 4 and 5). Overall, small-scale gold mining can severely impair the forest's ability to recover at abandoned mining pits and tailing ponds while recovery rates of woody biomass on the overburden zone were comparable to other secondary forests across the Neotropics following abandonment of pastures and agriculture (Chapter 5). Gold mining across the Amazon could potentially result in ~90,000 t C yr-1 less carbon being accumulated in relation to what would have accumulated under agriculture/pasture. Important conclusions from this work suggests that (1) national deforestation statistics need to include these small-scale events which are currently excluded from important official estimates such as Brazil's PRODES, and (2) active rehabilitation and restoration are required in order to assist the disrupted successional processes at gold mining sites. The results presented here highlight the vulnerability of Amazonian forests to newer, more intense types of land uses such as small-scale gold mining.
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Wessels, Deon. "The transformation of the South African gold-mining corporate culture." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53687.
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Thesis (MBA)--Stellenbosch University, 2003.ENGLISH ABSTRACT: Corporate cu~ure is the foundation of businesses today and in every way underties the way business is done. The discovery and subsequent mining of gold during the last century have shaped the gold-mining corporate cu~re; it gave birth to racial segregation and laid the foundation of the system in which the industry finds itse~ today. The purpose of this study is to uncover the deeper patterns of corporate cu~ure that drive visible behaviour and attitudes. Once the root metaphor or main undertying assumptions of the gold-mining corporate cutture have been determined, a process of multilevel, frame-breaking, radical transformation can be initiated. A 'paradigm interplay' approach, which describes cu~re as an explicit variable and an implicit root metaphor, was adopted. Within this frameworK the study aims to explore concepts and meanings of corporate cu~re in a hermeneutic fashion by uncovering the human, expressive, symbolic texture of life in a gold mine. The frameworK provided a way of thinking about organisations, not to present 1001s' or 'methods' for managing or transforming culture, but to think culturally and holistically about the process of transformation. An in-depth investigation into Schein's 'three levels of cu~re' model was necessary in order to derive at the core transformational aspect of the gold-mining corporate culture. An analysis of Schein's model indicated that behavioural characteristics are shaped and determined by undertying values, beliefs and attitudes, which are shared among members of the organisation. If not espoused, these in turn rest upon sets of undertying assumptions that are the innermost core of corporate cu~re. One such a se~ the nature of human relationships, had been identified as the main undertying theme behind the vested interests as well as ingrained paradigms that exist on both sides of a racially divided workforce. The historical background of the industry and cultural perceptions created a shared assumption set that shaped these deep-rooted, embedded mindsets, affecting human relationships significantly. The study made it clear that any transformation attempt could be possible only when one goes deeper than the stated values and norms to understand the undertying assumptions and the true nature of human relationships that drive the visible behaviour and attttudes. The central dimension of this study, the nature of human relationships, referred to the opposing concepts of individualism versus communalism. These opposing paradigms are manifested in the two main management approaches or corporate cultures that exist in South Africa. Many suggested that the acknowledgement and utilisation of the Afrocentric value system, Ubuntu, alongside a Westem individualistic corporate culture are imperative to improve relationships in general and promote humanism. This study proposed that the humane spirit of Ubuntu, a spirit of trus~ caring and respect for human dignity, should be 'married' with the Westem approach to management instead of Ubuntu being adopted as a single framework that may be perceived negatively by the current business community. Thinking culturally', the purpose phrase of this study, succeeded therefore in abandoning the eitheror kind of thinking in favour of a more holistic 'both-and' way of doing. A desired culture of trust, honesty, openness, integrity and non-
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MacMillan, Gordon John. "Gold mining and land-use change in the Brazilian Amazon." Thesis, University of Edinburgh, 1993. http://hdl.handle.net/1842/19965.
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This thesis explores how informal sector gold mining affects land development processes in the Brazilian Amazon. The 1987-1990 invasion of the Yanomami Indian reserve, in the state of Roraima, by 40,000 wildcat gold miners provides the context for research. Having analysed the macro-economic and political factors that sparked the gold rush, consideration is given to its impact on the land-uses in the state. Land-use change is analysed by looking at how different rural producers and urban dwellers adapted their management techniques and livelihood strategies to the opportunities arising in the mineral sector. Fieldwork in Roraima was undertaken over a 16 month period between November 1990 and March 1992. Quantitative data was collected on the rates at which different groups of land users participated in the gold rush, while subsequent recorded interviews provided qualitative information on their motives for involvement and how they incorporated mining within their other activities. A large proportion of local smallholders went gold mining in order to supplement their agricultural incomes. Understanding the household economics and risk aversion strategies associated with smallholder migration to the gold fields raises interesting questions concerning the management of the gold rush through appropriate agricultural policies. While this provides an insight into the geography of the labour movements associated with the gold rush, a detailed study of the relationship between informal sector mining and ranching sheds light on the capital flows linked to the mineral boom. As ranchers invested in the gold fields and successful miners bought ranches, changing circumstances in the mining economy came to influence management practices in the beef production sector. The implications that this has on deforestation and land conflict throughout the Brazilian Amazon are discussed. In this way, the mining boom is seen to influence people and places which are distant from the gold fields themselves. This is clearly apparent in the case of Roraima's riverine dwellers and Macuxi Indians. Even though these groups had minimal participation in the gold rush, their lives were profoundly altered by the economic and political changes that it provoked.
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Elbra, Ainsley Dianne. "Private governance: A study of sub-Saharan African gold mining." Thesis, The University of Sydney, 2015. http://hdl.handle.net/2123/13713.
Full textAbstract:
This thesis examines the role of private governance in sub-Saharan Africa’s largest gold producing countries. It seeks to provide an explanation for the role firms play in governing the gold mining sector in Ghana, South Africa and Tanzania. Furthermore, it seeks to illuminate the reasons why gold mining firms pursue self-regulation, beyond what is required by the state. The thesis begins with a summary of the resource curse literature, which suggests that countries rich in minerals (such as gold) are more likely to suffer slower economic growth and poorer development, when compared with their non-resource rich peers. It is from this scholarship that the thesis departs, suggesting that instead of solely focusing on the state, scholars of the underdevelopment in mineral rich states must consider the role of business in developing what is known as private governance. After advancing a classification system for private governance in the gold mining sector this research presents new empirical evidence in the form of analysis of company reporting and elite interviews with gold mining firm executives and representatives of industry associations. Using evidence gathered from interviews with mining executives, and company reports it is shown that firms do play a significant role in developing the rules and regulations that govern Africa’s gold mining industries. Large firms, with multiple operating jurisdictions are shown to be first-movers in engendering private governance, doing so in order to control the regulatory direction of their industry, but also to enhance their power vis-à-vis the state. This finding is elaborated on through the analysis of the elite interviews, where it is argued that gold mining firms with significant private authority rely on discursive power to develop private governance initiatives. Once these firms are seen as legitimate rule makers, they are able to effectively share sovereignty with sub-Saharan African governments.
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Zhang, Bo 1963. "Recovering gold from high density gangues with Knelson concentrators." Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=20934.
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This research documents the use of a 7.6 cm laboratory Knelson Concentrator (LKC) to determine the amount of gravity recoverable gold (GRG) content in ores and evaluate the performance of gravity circuits, with an emphasis on high gangue density. Two approaches were used to minimize the effect of the high gangue density in estimating the GRG content, oversize removal and 2:1 ratio dilution with silica flour.The amount of GRG was determined in four ore samples with an established protocol, yielding values of 35% to 78% of total gold.
Results from the Angnico-Eagle La Ronde Division (AELRD), Louvicourt and East Malartic mills suggest that the typical Knelson-based gravity circuit which can recover one half to two thirds of GRG from low density gangues will only recover one third to two fifths of the GRG from high density gangues. Simulation of gold recovery at AELRD showed that the high circulating loads, 700--1100%, were a significant factor in reducing gold recovery by gravity. (Abstract shortened by UMI.)
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Taylor, Mackenzie C. "GOLD FROM THE TYPE 4 ORE OF ROUND MOUNTAIN, NEVADA: A TEXTURAL AND MINERALOGICAL STUDY OF MACROCRYSTALLINE GOLD VS. DISSEMINATED GOLD." Miami University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=miami1512407677037903.
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Wortmann, Heid. "Sedimentation and desiccation of gold mines." Pretoria : [s.n.], 2007. http://upetd.up.ac.za/thesis/available/etd-11052007-152710.
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Moses, Lucian Benedict. "Flotation as a separation technique in the coal gold agglomeration process." Thesis, Cape Technikon, 2000. http://hdl.handle.net/20.500.11838/2155.
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Thesis (MTech (Chemical Engineering))--Cape Technikon, 2000.Internationally, there is an increase in the need for safer environmental processes that can be applied to mining operations, especially on a small scale, where mercury amalgamation is the main process used for the recovery of free gold. An alternative, more environmentally acceptable, process called the Coal Gold Agglomeration (CGA) process has been investigated at the Cape Technikon. This paper explains the application of flotation as a means of separation for the CGA process. The CGA process is based on the recovery of hydrophobic gold particles from ore slurries into agglomerates formed from coal and oil. The agglomerates are separated from the slurry through scraping, screening, flotation or a combination of the aforementioned. They are then ashed to release the gold particles, after which it is smelted to form gold bullion. All components were contacted for fifty minutes after which a frother was added and after three minutes of conditioning, air, at a rate of one I/min per cell volume was introduced into the system. The addition of a collector (Potassium Amyl Xanthate) at the start of each run significantly improved gold recoveries. Preliminary experiments indicated that the use of baffles decreased the gold recoveries, which was concluded to be due to agglomerate breakage. The system was also found to be frother-selective and hence only DOW-200 was used in subsequent experiments. A significant increase or decrease in the air addition rate both had a negative effect on the recoveries; therefore, the air addition rate was not altered during further tests. The use of tap water as opposed to distilled water decreased the attainable recoveries by less than five per cent. This was a very encouraging result, in terms of the practical implementation of the CGA process.
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Banisi, Samad. "An investigation of the behaviour of gold in grinding circuits." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=22400.
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A 7.6 cm (3") Knelson concentrator was used to estimate free gold content in samples extracted from industrial grinding and gravity circuits. Its recovery was comparable with that of amalgamation and the Mozley Laboratory Separator (MLS). It was then used for a study on gold grinding and classification behavior.Laboratory studies of monosized gold and silica showed that gold produces fewer fines upon grinding: 75% of the mass reports to the next Tyler class, as opposed to 45% for silica. Disappearance from the monosized class (840-1200 $ mu$m) follows first order kinetics for both minerals. However, the rate constant of gold was five to six times lower than that of silica, and folding predominated over actual breakage. Folding yields either spherical or cylindrical particles which flatten upon additional impacting.
Smearing of gold onto silica and embedding of silica into gold flakes were observed. It was postulated that gold smearing can lead to metallurgical losses in flotation circuits. A gravity circuit could then increase overall gold recovery.
The Knelson concentrator was used to study the behavior of gold in the Hemlo mill grinding circuit. The ratio of the selection function of ore to gold increased from 6 at 50-100 $ mu$m to 20 at 500-1000 $ mu$m. In the primary cyclones, gold's cut size was much finer than the ore, 20 vs. 57 $ mu$m.
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Edwards, Anita Kynne. "Characteristics of noise induced hearing loss in gold miners." Pretoria : [s.n, 2008. http://upetd.up.ac.za/thesis/available/etd-05062009-123505.
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Woodland, John George, and woodland@bigpond net au. "R. H. Bland and the Port Phillip and Colonial Gold Mining Company." La Trobe University. School of Historical and European Studies, 2002. http://www.lib.latrobe.edu.au./thesis/public/adt-LTU20041222.162756.
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There are numerous histories of the Victorian goldfields, individual digger�s experiences, and the digging community as a whole. By contrast, very little has been written about the early gold mining companies. This thesis seeks to address this dearth in part, with a longitudinal study of one of the leading gold mining companies in nineteenth-century Victoria. The Port Phillip and Colonial Gold Mining Company (�Port Phillip Company�) was one of many �gold bubble� companies formed in England during 1851-3 to undertake gold mining in Australia. Within a few years it was the only survivor of this episode of British corporate gold-fever. The thesis argues that the influence of Rivett Henry Bland, the company�s managing director, was instrumental in its success, particularly in its early years when faced with anti-company sentiment and unfavourable mining legislation. The company established a large-scale operation at Clunes in 1857, rapidly assuming a pre-eminent position in colonial gold mining with its superior technology and mining practices. Historians generally portray Australian gold mining operations as small, locally funded and inefficient, prior to British capital investment in the late 1880s. While true of the larger picture, this simply emphasises the uniqueness of the British-owned and funded Port Phillip Company, the largest and most efficient gold mining operation in Australia from 1857 until the early 1880s. The company and its investment offshoot, the Victoria (London) Mining Company, invested in over thirty Victorian gold mining companies during the 1860s. Again, this runs counter to the general view that British investment in Australian gold mining began only in the late 1880s. Although the two companies� investments equalled only a fraction of the later wave of British capital in absolute monetary terms, their contribution to the growth of the Victorian gold mining industry at the time was significant.
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Akinpelu, Enoch Akinbiyi. "Bioremediation of gold mine wastewater using fusarium oxysporum." Thesis, Cape Peninsula University of Technology, 2014. http://hdl.handle.net/20.500.11838/918.
Full textAbstract:
Thesis submitted in fulfilment of the requirements for the degree
Magister Technologiae: Chemical Engineering
in the Faculty of
Engineering
at the
Cape Peninsula University of Technology
2014The legislative requirements for handling cyanide containing wastewater have become stringent internationally. Cyanide properties make it indispensable in the mining industry especially for gold recovery. The resultant wastewater generated is discarded to tailing ponds. Any leakages or total collapse of tailing ponds can result in the contamination of surface water bodies; endangering aquatic organisms’ and humans’ alike. The over reliance on physical and/or chemical treatment methods for cyanide wastewater treatment is not sustainable due to high input costs and the generation of by-products. A feasible alternative treatment method for cyanide contaminated wastewater is the biodegradation method, as a wide range of microorganisms can degrade cyanide. In this study, the cyanide biodegradation ability of Fusarium oxysporum was assessed in two stages. Firstly, optimal operating conditions for maximum cyanide biodegradation were determined using a central composite design (CCD) at an elevated cyanide concentration, i.e. 500 mg F-CN/L. Thereafter, using the optimum conditions obtained, (i.e temperature 22°C and pH 11), cyanide biodegradation kinetics and microbial growth kinetics in the cultures at lower cyanide concentrations of 100, 200 and 300 mg F-CN/L were assessed. This was followed by the assessment of cyanide biodegradation at a temperature of 5°C, which was used to simulate winter conditions. In general, lower cyanide concentrations are used in the extraction of gold, therefore, the resultant wastewater will contain free cyanide concentration less than 300 mg F-CN/L. For the first stage of experiments, an isolate, Fusarium oxysporum from cyanide containing pesticides was cultured on potato dextrose agar (PDA) plates, followed by incubation at 25°C for 5 days. A response surface methodology (RSM) was used to evaluate design parameters for the biodegradation of cyanide by this fungus. The temperature evaluated at this stage ranged from 9°C to 30°C and pH range of 6 to 11 in cultures solely supplemented with agrowaste, i.e Beta vulgaris waste. Beta vulgaris is commonly known as Beetroot. The Fusarium oxysporum inoculum (2% v/v) was grown on a Beta vulgaris waste solution (20% v/v), as the sole carbon source in a synthetic gold mine wastewater (39% v/v) containing heavy metals; arsenic (7.1 mg/L), iron (4.5 mg/L), copper (8 mg/L), lead (0.2 mg/L) and zinc (0.2 mg/L), for 48 hours using a rotary shaker at 70 rpm. Thereafter, free cyanide as a potassium cyanide solution (39% v/v), was added to the cultures to make a final cyanide concentration of 500 mg F-CN/L in the culture medium which was incubated for a further 72 hours at 70 rpm. Optimal operating conditions for the biodegradation of cyanide were then determined using a numerical option in the Design-Expert® software version 6.0.8 (Stat-Ease Inc., USA). Subsequently, using the optimal pH obtained (pH =11) and a preselected temperature of 5°C (to represent winter conditions), cyanide biodegradation rates and microbial growth kinetic studies were carried out using Beta vulgaris waste containing a Fusarium oxysporum (0.7% v/v; grown overnight) inoculum in wastewater (32.7% v/v) and potassium cyanide in phosphate buffer (53.7% v/v). The cultures contained 100, 200 and 300 mg F-CN/L. The cultures were incubated in an orbital shaker at 70 rpm for 144 hours and samples taking every 24 hours. An Ordinary Differential Equation (ODE) solver (Polymath) was used for modelling cyanide degradation kinetics while the Monod’s growth kinetic model was used to monitor the microbial growth parameters of the cultures. For the first stage, the optimum operating conditions were determined as a temperature of 22°C and a pH of 11 for maximum cyanide biodegradation of 277 mg F-CN/L from an initial cyanide concentration of 500 mg F-CN/L over a 72 hour period, with residual ammonium-nitrogen and nitrate-nitrogen of 150 mg NH4+-N/L and 37 mg NO3--N/L, respectively. Although, the residual ammonium-nitrogen inhibited cyanide biodegradation, it was consumed as a nitrogen source for microbial growth. The Beta vulgaris waste was determined to be a suitable substrate for cyanide degradation. From the biodegradation response quadratic model, temperature was determined to influence cyanide biodegradation. For the cyanide degradation kinetics, at an optimum temperature of 22°C, the biodegradation efficiency was 77%, 58% and 62% with the corresponding maximum microbial population of 1.56 x 107, 1.55 x 107 and 1.57 x 107 CFU/mL for 100, 200 and 300 mg F-CN/L, being achieved. An indication that the F. oxysporum cultures were efficient at lower cyanide concentration. Furthermore, at a temperature of 5°C, the biodegradation efficiency, although slightly lower, was 51%, 43% and 44% with the corresponding maximum microbial population of 1.21 x107, 1.11 x 107 and 1.12 x 107 CFU/mL for 100, 200 and 300 mg F-CN/L cultures, respectively, with minimal differences observed for cultures with 200 and 300 mg F-CN/L. The cyanide biodegradation rates increased with temperature increases and varied with different cyanide concentrations below 500 mg F-CN/L. The estimated energy of activation for cyanide degradation for a change in temperature from 5°C to 22°C using the Arrhenius model was 19.6, 12.7 and 14.9 kJ/mol for 100, 200 and 300 mg F-CN/L, respectively. The means and standard deviations for rate of degradation of cyanide at 5°C and 22°C for the ODE models was 0.0052 (± 0.0011) h-1 and 0.0084 (± 0.0027) h-1, respectively. The inhibitory effect of the cyanide was quantitatively pronounced under cold temperature as the heavy metals, residual ammonium-nitrogen and nitrate-nitrogen hindered the cyanide degradation. Similarly, microbial growth rates increased with a temperature rise (from 5°C to 22°C), resulting with a reduction in the microbial populations’ doubling time. When compared with the simulated winter conditions, the specific population growth rate increased 4-fold, 5-fold and 6-fold in 100, 200 and 300 mg F-CN/L, respectively, for higher temperatures; an indication that the Fusarium oxysporum isolate prefers higher temperature. The estimated energy of activation for cellular respiration was 44.9, 54 and 63.5 kJ/mol for 100, 200 and 300 mg F-CN/L cultures, respectively, for the change in temperature from 5°C to 22°C. The means and standard deviations of microbial growth rate at 5°C and 22°C were: 0.0033 (± 0.0013) h-1 and 0.0151 (± 0.0027) h-1, respectively. The difference in error (standard deviation) of the cyanide biodegradation rate and microbial growth rate was insignificant (0.02% at 5°C) especially at temperature 22°C where there were minimal differences, indicating the reliability and reproducibility of this biodegradation system in batch operated bioreactors.
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Laidlaw, Noel. "The mechanisation of saddle reef stoping on the Bendigo goldfield." Thesis, The Author [Mt. Helen, Vic.] :, 1994. http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/55799.
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The purpose of the study was to examine the effect of a group training program, based on cognitive behavioural theory and techniques, on the problem-solving skills of adolescents. Evidence of a link between suicidal ideation (engaging in suicidal thinking) and reported deficits in social problem-solving or coping competence levels in adolescents is an area of investigation that offers some hope for suicide primary prevention programs. The study tried to determine if teaching social problem solving skills in a school would better equip adolescents with coping with problematic situations. The work of Hawton (1997) Hawton and Kirk (1989), Lerner and Clum (1990) and McLeavey, Daly, Ludgate and Murray (1994) formed the basis of the training program design. The emphasis was on general problem-solving skills rather on a participant’s specific current problems. Included was training in listening skills, assistance in developing problem-solving skills rather on a participant’s specific current problems. Included was training in listening skills, assistance in developing appropriate problem-solving behaviours and role simulation through the use of structured video case scenarios. Seventy four male and female year 10 secondary school students were subjects in the study. They were randomly divided into two, approximately equal, groups. Thirty six subjects established the control group and the remaining thirty eight constituted the experimental group. The findings indicated that students exposed to the problem solving training program did not have significantly higher problem-solving ability, as measured by the Problem Solving Inventory (PSI) than those who were not exposed to the training. However, females in the experimental group were significantly more likely to make conscious decisions about when they would approach or avoid a problem when compared to control group females. It is suggested that the adaptation of training, designed for suicidal clients, needs to be explored further for application to Year 10 students in the general population. More research is needed into ways to provide school based preventative training programs that will assist in the development of coping skills.School of Science & Engineering
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Logsdail, Andrew James. "Computational characterisation of gold nanocluster structures." Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/3320/.
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This thesis presents computational work on the structures, characterisation and optical properties of homogeneous gold nanoclusters, and gold-containing bimetallic nanoalloys. An introductory overview of nanoscience is followed by four results chapters in which various computational methods are applied to elucidate properties that are not fully understood; from these results areas for future development, and application, are identifed. Chapter 2 looks at structural motif preference as a function of composition and size for Au and Pd. Bimetallic (AuPd)_N particles are further studied, with thermodynamic preference found for Au_shellPd_core configurations with a monolayer Au shell. Chapter 3 discusses the development and implementation of a genetic algorithm designed to aid the determination of the structures of small nanoclusters from images taken with a scanning transmission electron microscope. The implementation of a search method proves efficient at identifying high-symmetry test clusters, and shows promise for further application to the identification of cluster structure from experimental images. Chapter 4 contains a first-principles study of Au₁₆ deposited on a graphite substrate. We introduce surface defects to see their influence on the nanocluster structure, as well as testing for potential catalytic applications. Finally, Chapter 5 looks at the optical response of monometallic and bimetallic nanoparticles. Surface plasmon resonance spectra are calculated for a variety of geometries, compositions and chemical ordering. The greatest influence on the extinction spectra is attributed to the particle shape and its environment.
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Matunhire, I. "The economics of small-scale mining : Zimbabwe." Thesis, University of Nottingham, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373814.
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Sibbick, Steven John Norman. "The distribution and behaviour of gold in soils in the vicinity of gold mineralization, Nickel Plate mine, southern British Columbia." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/28862.
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Sampling of soils and till are conventional methods of gold exploration in glaciated regions. However, the exact nature of the residence sites and behaviour of gold within soil and till are poorly known. A gold dispersion train extending from the Nickel Plate mine, Hedley, southwest British Columbia, was investigated in order to determine the distribution and behaviour of gold within soils developed from till.
Three hundred and twelve soil, till and humus samples (representing LFH, A, B and C horizons) were collected from fifty-two soil pits and thirty-four roadcut locations within the dispersion train. Soil and till samples were sieved into four size fractions; the resultant -212 micron (-70 mesh) fraction of each sample was analysed for Au by FA-AAS. Humus samples were ground to -100 micron powder and analysed for Au by INAA. Based on the analytical results, each LFH, A, B and C horizon was subdivided into anomalous and background populations.
Detailed size and density fraction analysis was carried out on soil profiles reflecting anomalous and background populations, and a mixed group of samples representing the overlap between both populations. Samples were sieved to six size fractions; three of the size fractions (-420+212, -212+106, -106+53 microns) were separated into two density fractions using methylene iodide and analysed for Au by FA-AAS. The Au content of the -53 micron fraction was analysed by FA-AAS and cyanide extraction - AAS.
Results indicate that the Au content of soil profiles increase with depth while decreasing with distance from the minesite. Heavy mineral concentrates and the light mineral fraction Au abundances reveal that dilution by a factor of 3.5 occurs within the till over a distance of 800 metres. However, free gold within the heavy mineral fraction is both diluted and comminuted with distance. Recombination of size and density fractions indicate that the Au contents of each size fraction are equivalent; variation in Au abundance is not observed with a change in grain size. Seventy percent of the Au in the -53 micron fraction occurs as free gold.
Chemical activity has not altered the composition of gold grains within the soil profiles. Compositional and morphological differences between gold grains are not indicative of glacial transport distance or location within the soil profile. Relative abundances of gold grains between sample locations can be used as an indicator of proximity to the minesite. The sampling medium with the best sample representivity and contrast between anomalous and background populations is the -53 micron (-270 mesh) fraction of the C horizon. Geochemical soil sampling programs in the vicinity of the Nickel Plate mine should collect a minimum mass of 370 grams of -2000 micron (-2 mm) soil fraction in order to obtain 30 grams of the -53 micron fraction.Science, Faculty of
Earth, Ocean and Atmospheric Sciences, Department of
Graduate
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Roopnaraine, Terence Robin Rupert. "Freighted fortunes : gold and diamond mining in the Pakaraima Mountains, Guyana." Thesis, University of Cambridge, 1996. https://www.repository.cam.ac.uk/handle/1810/251603.
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Kritzinger, Louise. "Confronting gold mine acid drainage : art as counter-activity." Diss., University of Pretoria, 2012. http://hdl.handle.net/2263/27490.
Full textAbstract:
Environmental art: Art relating to the individual’s response, understanding and interest towards the land, including art forms such as Land/Earth art as well as more sensitive art forms such as Eco-art, focussed more on the earth’s natural processes. Exploitation: The exploitation of mineral resources is closely associated with progress and success, but also that of benefiting from something at the cost of something else, in this case exploiting gold at the cost of the ecology of the natural environment. Gold mining industry: The labour-intensive activity of removing gold from ore, mined from deep within the earth’s crust through a system of shafts and stopes. Installation art: Refers to what is contested as being a medium or process of art, whereby three-dimensional works are designed to influence the perception of a space, often site-specific, within an enclosed space or the outside environment, temporary or permanent. The found object or existing object is often used in installation art for its intellectual value. Inter-and-trans-disciplinary approach: The utilisation and collaboration of different disciplines as a means to find a solution to a (environmental) problem. Landscape: A cultural construct, referring not to physical topography, but to an aesthetically processed vision of the environment, mostly arranged and framed by an artist. Post-industrial environment: Referring to an environment, man-made or natural in a state preceded by industry. Often these environments are characterised as polluted and derelicts sites left behind by large mining industries. The gold-mining industry on the Witwatersrand, is characterised by massive tailings dumps and slimes dams. Resource curse: A term coined by artist Jeannette Unite, describing the phenomenon of extreme poverty co-existing with valuable minerals in the same region, especially prevalent in Africa. Technospasm: A term conceptualised by archeo-metallurgist Duncan Miller, as the unsustainable rate of non-renewable mineral resources extraction. South Africa is known to the world for its vast deposits of valuable minerals, of which gold has played a seminal role in the development of the country’s economy. What is left after more than 120 years of mining for this precious metal is a landscape, better described as a derelict post-industrial environment, characterised by pollution and impoverished communities. Environmental degradation caused by mining industries is not unique to the African continent, but is a worldwide phenomenon. Due to the rapid deterioration of environments caused by mining and industry, new environmentalist attitudes became prevalent by the 1970s in the West, seeking change in attitudes towards the land. Along with earth activists, artists also started to question humankind’s destructive relationship towards the land. Apart from the early developments of Land/Earth art during the 1960s, artists have taken on roles of activists, interventionists and collaborators of multi- and interdisciplinary projects since then, in order to remediate and re-cultivate post-industrial sites. Environmental artists find value in what art holistically contributes to society, as opposed to the commodity value of art. While artists in the West significantly progressed in environmentally orientated art, South African artists focused more on responding to the socio-economic conditions induced by the long-standing Apartheid era. Few South African artists have attempted to engage in environmentally-concerned art, especially related to the mining industry. However, Western attitudes towards the land can be derived from South Africa’s landscape depictions since its colonisation by Europeans up to contemporary versions of the South African landscape environment today. This study provides a historic overview of South Africa’s aesthetic relationship with the mining landscape, specifically of the post-industrial sites situated in the Witwatersrand. The aim is to determine the South African artists’ contribution towards developing an environmental awareness, and to call for more artists to take part in visual art forms concerning the disruption of the environment, caused by the mining industry. The study determines the relevance of art as a means to raise environmental issues and whether art may be utilised for post-industrial remediation projects. International examples of Reclamation art projects and its incorporation of science are investigated to find solutions towards contaminated post-industrial sites. These examples are compared to the work of a small number of South African artists who have attempted to engage in the post-industrial mining environment through Earthworks and science The researcher’s own work is discussed to raise awareness of the adverse effects of Acid Mine Drainage (AMD) caused by the gold-mining industry in the Witwatersrand. A body of installation art produced for this degree was displayed in a gallery space, which presented a platform for audience engagement. Through this body of work and through the examples discussed in this dissertation, the researcher urges South African artists to take up the task of moral responsibility towards the environment for the survival of future generations of life on earth.Dissertation (MA)--University of Pretoria, 2012.
Visual Arts
unrestricted
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Vincent, Frédérique. "A comparison of Knelson concentrator and jig performance for gold recovery /." Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=21333.
Full textAbstract:
A 7.6 cm Laboratory Knelson Concentrator was used to evaluate the performance of one jig circuit (Snip Operation), four Knelson Concentrators circuits (Meston, Est Malartic, Aurbel and Hemlo) and one classification circuit (Agnico-Eagle). To determine the size-by-size unit performance of all units, total and gravity recoverable gold contents were measured in the feed, concentrate, tails, underflow and overflow. Sample dilution with silica was used as a tool to enhance LKC recovery in samples with a high sulphide content.The data generated from the Knelson and the jig was used in a model designed to simulate an actual grinding and gravity circuit, and to predict its GRG recovery. It describes gold liberation, breakage and classification behaviour, and the GRG recovery performance curve of the chosen gravity unit. The simulation of the Snip circuit reproduced the recoveries obtained at the plant, and predicted that the use of a 20" Knelson, replacing the jig, would bring the recovery from 3 3% up to 43%. (Abstract shortened by UMI.)
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Gray, Matthew Dean 1933. "Gold mineralization in the Black Cloud #3 carbonate replacement orebody, Leadville Mining District, Lake County, Colorado." Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/558083.
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Naidoo, Kumendrie. "Considerations for stope gully stability in gold and platinum mines in South Africa." Diss., Pretoria : [s.n.], 2001. http://upetd.up.ac.za/thesis/available/etd-11302005-123445/.
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Beavogui, Massa. "Structural controls of gold mineralisation in Seguelen pit of Siguiri gold mine, Guinea." Thesis, Rhodes University, 2015. http://hdl.handle.net/10962/d1019879.
Full textAbstract:
The present study provides the results of detailed mapping and analysis of structures encountered in Seguelen pit of Siguiri gold mine, Guinea, where the Siguiri mine is geo-tectonically located in the Baoulé-Mossi domain of Man Shield in West African craton. The gold deposit is hosted in low-grade metamorphic sediments of turbidites sequences which form part of the Lower Proterozoic of Birimian Super group. Three rock formations of Balato, Fatoya and Kintinian underlay the overall pits. The Siguiri gold mine is characterized by the deep weathering profile, developed over the rocks reaching 200 m below the surface in some areas and often capped by the lateritic gravel or duricrust. The rock formations at Seguelen area are characterised by strong bedding monotonously dipping towards SW and trending NW-SE. The lithology of the host rocks has strong control on the disseminated mineralisation throughout the deposit. Two domains of rock formations are clearly distinguished at Seguelen: Fatoya Formation(Ffm) domain ; and Kintinian Formation (Kfm) domain. The two domains are separated by a contact zone of 1.7 m wide parallel to bedding and characterised by the presence of quartz fragments as well as thinly sheeted shale and black shale. This contact zone is identified as disconformity. The major tectonic deformation which has affected the region is known as D2 corresponding to the Eburnean orogeny. The major D2 related structures is the regional thrust striking N-S over an area of 12 km long and 3 km wide and within which corridors all Siguiri gold Mine open pits are located. In the N-S trending structures, there is east-northeast shortening and north-northwest extension. There is pervasive hydrothermal alteration (carbonatization and sideritization) and supergene alteration in the all pits. The hydrothermal alteration attests the intensity of hydrothermal fluid-flow over the host rocks. The hydrothermal fluids flowed along the fractures and within the wall rocks through bedding plans to form numerous auriferous quartz veins bearing disseminated sulphides through chemical reaction between fluids and wall rocks, which are remarkable at Seguelen pit. Three quartz vein sets are distinguished at Seguelen: NNE-SSW quartz vein set NE-SW quartz vein set NW-SE quartz vein set The NE-SW and NNE-SSW quartz veins are often lenticular and associated with the bulk mineralisation.
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Barclay, Jared Scott. "Golden Years: Gold Mining Equity Returns After Introduction of the All-In Sustaining Cost Metrics." Scholarship @ Claremont, 2019. https://scholarship.claremont.edu/cmc_theses/2239.
Full textAbstract:
Previous empirical studies show that returns on gold mining equities are positive and statistically significantly related to changes in the price of gold. However, these studies fail to examine operational factors that may provide further explanatory power to gold mining equity returns. Examining quarterly gold mining equity returns, All-In Sustaining Cost and gold production results between 2013 and 2018, I find that there exists a positive and statistically significant relationship between changes in gold mining equity returns and the price of gold and a negative and statistically significant relationship between lagged changes in All-In Sustaining Cost and gold mining equity returns. My findings suggest that investors must be cognizant of cost metrics when seeking gold exposure through gold mining equities.
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Woodcock, Frederick C. "Use of a knelson unit to quantify gravity recoverable gold in an ore." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=55416.
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A method to determine the amount of gravity recoverable gold in an ore sample with a 7.5 cm (3 inch) Knelson Centrifugal Concentrator is presented. The method is based on sequential comminution and recovery steps, the first at 100% $-$841 $ mu$m, the second at approximately 50% $-$74 $ mu$m and the third at final grind (typically 75 to 90% $-$74 $ mu$m). The mass processed depends on the gold grade and particle size, and commonly varies from 25 to 100 kg.The method was used to determine the gravity recoverable gold in nine different ore samples. The grade of these ores ranged from 3 g/t to 45 g/t. Both massive sulfide and silicate ores were tested. Gold in the ores ranged from fine (90% $-$210 $ mu$m) to coarse (60% +841 $ mu$m). The amount of gravity recoverable gold ranged from 29 to 93%. Results from the proposed test compare favorably with mineralogical studies and data from industrial gravity recovery circuits. Some problems arose while testing the various ores; minor adjustments to the procedure were made to correct these. These corrections and other caveats for the test procedure are discussed.
This test yields an essential component of an algorithm that can be used to predict the amount of gold that can be recovered by installing a gravity circuit. This algorithm is referenced and an example of its use is included. Information from the test can be used to evaluate circuit performance and indicate if the performance is equipment or process limited. The test will quickly indicate if a gravity circuit is an option.
Results indicate that sizing material before it is processed with a Laboratory Knelson Concentrator leads to significant increases in recovery (48% without screen to 64% with). Industrial results are not yet available to verify this.
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Scott-Russell, Hugh. "The application of mechanised loading and drilling methods in the gold mining industry." Thesis, University of Nottingham, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.352962.
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Squelch, Andrew Peter. "Application of virtual reality for hazard awareness training in South African gold mines." Thesis, University of Nottingham, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243505.
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Devi, Bernadetta Puspita. "Governing the interface of commercial mining and artisanal and small-scale gold mining (ASGM) in Indonesia." Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/209570/1/Bernadetta_Devi_Thesis.pdf.
Full textAbstract:
This thesis examines the governance of the interface between commercial mining and artisanal and small-scale gold mining in Indonesia. It does so from the under-addressed perspective of artisanal and small-scale gold mining. Using a critical governmentality lens, the research discovered artisanal and small-scale gold miners are neglected because of governmental techniques adopted by global and national bodies to eliminate mercury use. Concurrently, these miners have created alternative knowledge and practices through counter-discourses, conduct and strategies to ensure their mining agenda can progress. This research advocates for inclusion of artisanal and small-scale miners in mining governance to promote mining sustainability.