No description available.

Thesis (M.E.S.)--Evergreen State College, 2008. / "June, 2008." Title from title screen (viewed 4/8/2010). Includes bibliographical references.

Thesis (M. Sc.)--Carleton University, 1992. / Also available in electronic format on the Internet.

Orientador: Ticiano José Saraiva dos Santos / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociências / Made available in DSpace on 2018-08-20T02:37:11Z (GMT). No. of bitstreams: 1 MiguelJunior_Emilio_M.pdf: 6909901 bytes, checksum: 2eaa2f163eec136b6a2c6271bbc76e8a (MD5) Previous issue date: 2011 / Resumo: No setor leste da Província Aurífera de Alta Floresta (PAAF) as mineralizações auríferas, em sua maioria, ocorrem em veios, sistemas de veios ou disseminados em rochas graníticas. A maioria dos depósitos encontra-se numa faixa NW-SE, com aproximadamente 30 km de largura e 140 km de extensão, denominada Peru - Trairão. Os filões nesta faixa são sub-verticais, com direções variadas e estão relacionados à uma gênese magmática-hidrotermal na forma de veios de quartzo associados a fraturas e/ou zonas de cisalhamento dúctil a rúptil-dúctil. Os sistemas filoneanos auríferos são agrupados em quatro principais sistemas estruturais, com base na disposição das estruturas mineralizadas: (a) Sistema Novo Mundo: WNW-ESE e N-S em regime dúctil e NW-SE em regime rúptil (e.g. região de Novo Mundo); (b) Sistema Flor da Serra: NNE- SSW e WNW-ESE em regime rúptil (e.g. região de Flor da Serra); (c) Sistema Peixoto: N-S, NNE-SSW e NW-SE em regime dúctil a rúptil (e.g. região de Peixoto de Azevedo) e; (d) Sistema União do Norte: E-W regime dúctil e NE-SW em regime rúptil (e.g. sudoeste de Vila União do Norte). Datações U-Pb em zircão por LA-ICP-MS nos granitóides mineralizados no cinturão de cisalhamento têm as seguintes idades de cristalização: (i) quartzo-feldspato pórfiro (Pórfiro União), 1774± 7.5 Ma, relacionada ao magmatismo pós-colisional; (ii) granodiorito União com 1853±23 Ma que abriga os depósitos do Bigode, Bernaldo e Carrapato; e (iii) Granito Aragão de 1931±12 Ma que abriga os depósitos do Aragão e Jurandir; (iv) monzonito da Suíte Intrusiva Pé Quente de idade 1979±31Ma que abriga vários depósitos auríferos. Esses dados caracterizam temporalmente os principais corpos graníticos com associação espacial para ouro, tanto do ponto de vista da sua época de cristalização quanto dos limites aproximados dessas mineralizações, e contribuem para um melhor entendimento da evolução crustal da região. Estudo de proveniência U-Pb em zircões detríticos na unidade vulcanoclástica (grauvaca feldspática) da seqüência vulcano-sedimentar Serra Formosa, hospedeira do depósito aurífero do Francisco, têm valores entre 1.7 e 2.0 Ga, indicando uma proveniência essenciamente de fontes paleoproterozóica / Abstract: In the eastern sector of the Alta Floresta Gold Province (AFGP), the gold mineralization occurs mostly in veins, systems of veins or disseminated in granitic rocks of the stockwork. Most of these deposits are found in a NW-SE region, with an approximate range of 30 km wide and 140 km long, and it is called Peru - Trairão, because it extends from the north region to the south region in Peru. The veins in this range are sub-vertical, with variable directions and are related to magmatic-hydrothermal genesis in the form of quartz veins associated to fractures or ductile shear zones in brittle-ductile. The filoneans auriferous systems are grouped into four main structural systems, based on the disposal of mineralized structures: (a) System Novo Mundo: WNW-ESE and NS under ductile regime and NW-SE under brittle regime (e.g. Novo Mundo-MT region) (b) System Flor da Serra: NNE-SSW and WNW-ESE under brittle regime (e.g. Flor da Serra region), (c) System Peixoto: NS, NNE-SSW and NW-SE under ductile to brittle regime (e.g. Peixoto de Azevedo region) and (d) System União do Norte: E-W under ductile regime and NE-SW under brittle regime (e.g. Vila União do Norte region). Dating with U-Pb in zircon by LA-ICP-MS in mineralized granites in the shear belt define the following crystallization ages: (i) Quartz-feldspar Porphyry (União Porphyry), 1774±7.5 Ma, related to post-collisional magmatism; (ii) União Granodiorite, 1853±23 Ma that holds the deposits Bigode, Bernaldo and Carrapato; (iii) Aragão Granite, 1931±12 Ma that holds the deposits Aragão and Jurandir; (iv) Suíte Intrusiva Pé Quente Monzonite with the age of 1979±31Ma and holds several gold deposits. These data delimit the date of the main granitic bodies with spatial association for gold, both as the point of its period of crystallization as the approximate limits of these mineralizations, and contribute to a better understanding of the crustal evolution in the region. Provenance study with U-Pb in detrital zircons in the volcaniclastic unit (feldspathic greywacke) of Serra Formosa volcano-sedimentary sequence, the host of the gold deposit Francisco, that has values between 1.7 and 2.0 Ga, indicating an essential provenance of Paleoproterozoic sources / Mestrado / Geologia e Recursos Naturais / Mestre em Geociências

M.Sc. (Geography) / Gold mine tailings deposits in the Witwatersrand are subjected to intensive wind and water erosion the combination of factors responsible for air and water pollution. Numerous efforts to alleviate this problem through vegetation have succeeded in establishing soil cover, although the surviving species are not representative of original indigenous vegetation and longer-term soil establishment has been poor. Contributing to these difficult conditions for establishing stable soil and plant communities are: low pH values; low surface stability; deficient organic matter and nitrogen; and high levels of heavy metal in the tailings. Although the role of cryptogams on nutrient cycling and positive impacts on growth of plants is well documented, their potential use in the planning of rehabilitation programmes of gold mine tailings has not been explored. In this study, the abundance and diversity of cryptogams and their impact on the chemical properties of Tailings Storage Facilities (TSF) surface material were investigated on three selected tailings dams: Fleurhof (2L3), Rand Leases (2L8), and Durban Roodepoort Deep DRD (2L24). On the third TSF, DRD (2L24), the original vegetation on the northern half has been entirely covered by wind- eroded material from the southern half the current surface represents a fresh un-vegetated surface. Field investigation was conducted to determine the abundance, diversity and coverage of cryptogams and their effect on the surface stability of the selected tailings. Bacteria, cyanobacteria and fungi were isolated and identified to evaluate the diversity and abundance of these organisms in the study area. In addition, electron microscopy observations were performed to understand the formation of the TSF crust. Chemical analyses of pH, electrical conductivity and the nutritional level of cryptogams TSF material were conducted to determine the effects of cryptogams on the chemical properties of the TSF material and predict the suitability of the substrate for the establishment of other microbes and vegetation. Abundant cryptogams, with diversified growth and morphological features, were found within the sampled areas. The cryptogam diversity proved similar to those across the three tailings dams, and was dominated by mosses and lichens. The abundance and growth of these mosses and lichens was dependent on the presence of vegetative cover and the direction of solar radiation. On undisturbed sites, cryptogams covered as much as 30% on DRD, 70% on RL, and 80% on FL. It was observed that the TSF surfaces covered by cryptogams were more stable than the bare ones. Ten genera of cyanobacteria were isolated from samples for the three tailings and identified, based on their morphology and growth characteristics, as: Aphanocapsa sp., Chromonas sp., Chroococcus sp., Cyanothece sp., Microcystis aeruginosa; Microcoleus sp., Nostoc sp., Oscillatoria sp, Scytonema sp. and Stigonema sp. Five fungal (Trichoderma gamsii, Phoma sp., Hypocrea lixii, Lecythophora sp, and Ascomycota) and four bacterial species (Bacillus subtilis, Arthrobacter aurescens, A. histidinolovorans, and A. sulfonivorans), representing the most abundant isolates from each group, iv were identified using DNA sequencing. Under the electron microscope, it was observed that the cryptogams being examined constituted diversified groups of organisms. Mycelia mats and sheathe produced by filamentous cyanobacteria and fungi played a major role in the formation of the crust by binding the TSF particles. The substrate had very low pH, EC, organic matter and nutrients essential for plant growth. However, the presence of cryptogams altered the acidity of the surface material into almost neutral and significantly improved the level of the essential nutrients and organic matter. It was concluded that the diversity of cryptogams in the TSF material was comparable to the diversity reported on other (different) soils. In addition, the cryptogams’ role in ameliorating the chemical properties of the surface material of the TSF is a clear indication that these organisms can play a positive role in stabilising the tailings material surface and promoting the growth of other microbes and higher plant forms.

M.Ing. / Safety within the mining industry is a primary concern for everyone involved. More specifically, active below-ground stope support for South African Mines is becoming increasingly important due to a renewed emphasis on the safety and well-being of the people actually working underground. It is imperative that all stope support systems are rigorously tested, continuously, both under laboratory conditions and in-situ to prove their performance and manufacturing standards. The Rocprop was initially manufactured in 1995 with the first two hundred props being installed at East Driefontein Consolidated Gold Mine in the Carletonville area. In the three years since the first introduction over three hundred thousand Rocprops have been manufactured and sold to South African Mines with the number steadily increasing. The Rocprop is a tubular support consisting of two tubes — a Ø139mm 'inner' tube and a Ø152mm 'outer' tube. One end of each tube is sealed by dome ends which are welded onto the tube mouths. The two tubes, cut to identical lengths, fit inside one another and extend telescopically during installation. Once the desired height has been reached, leaving enough tube overlapping to ensure the support does not buckle, the wedge is hammered in locking the prop at that height. The water is then removed after which the prop will provide active support of the rock mass above it. One of the components responsible for the Rocprops success is a dome end. This is either a forging or a pressing welded onto each end of the support and allows continual concentric loading throughout the life of the Rocprop. At present the dome ends are pressings, manufactured into hemispheres from 10mm mild steel plate in one action. The reason for the Rocprop's success is its performance characteristics. It's all metal construction, ease of installation, reliability and predictability in both seismic and static conditions, fire resistance, blast resistant, economically viability and versatility have made the prop successful. Reasons for the research were to investigate the dome end forming process in general and to investigate current numerical analysis techniques ability to predict loads during manufacture, the final shape, spring-back and other local deformation areas. Also to investigate alternate manufacturing methods such as cold forming, which provides advantages such as better mechanical properties and higher structural capabilities. The use of alternate materials in the Rocprop manufacture has been an ongoing process for MSP, manufacturer and current licensee holder of the Rocprop. A substitute for the current dome end manufactured from mild steel was investigated. For the substitute to be viable the material should be stronger, weigh less and be cost effective. In depth knowledge about the forming of the dome end at various velocities was gathered, providing information for further optimisation of the component.

D.Phil. (Zoology) / South Africa is a major gold-producing country with the 43 larger mines processing approximately 120 x 106 ton of milled and processed ore and about 30 x I06 ton of mined waste rock. Pollution of both surface and ground water, which can be attributed to the influences of gold-mining, are well known. Acid mine drainage, characterized by a low pH and high concentrations of dissolved metals, and seepage, from active and disused mine-tailings, are two of the main environmental problems associated with gold mining operations in South Africa. A growing concern for the environment and a stricter approach to water pollution by government agencies have made it necessary to investigate the type of effects which the gold mining industry is responsible for, and to develop action to reduce these impacts. The present study focused on procedures to access the effect of gold-mining effluent on the natural surface environment. The study is divided into three separate identities. The mine represented as Ccse study Mine One is considered to be a major contributor of salt loads to the natural stream on the property of the mine. This stream confluences with the Klip River outside the mined area. This mine has only one discharge point of underground mine service water, and is considered to be the main point source of pollution for the mine. As the mine makes use of an open water circuit, the quality and quantity of effluent have a direct effect on the downstream users. It appears that one of the main water quality problems of this open water circuit is the creation of surface water with a very low pH. Part of the problem is the geology of the area which consists of shales, which has a natural low buffering capacity. Because of the low pH the wetlands are not very effective. Metal concentration changes are possibly the direct result of the low pH of the both the water column and sediment. Improving the pH of the surface water can leads to reduced metal concentrations in the water, with possible increased concentrations in the sediment and wetland vegetation. Case Study Mine Two was conducted at a gold mine in the Far West Rand Mine region. The mine can be classified as having a closed water circuit, in that only excess water is discharged. The volume of water discharged is dependent on a number of factors, such as rainfall, wash-down service water and changing demands in sewage treatment systems. The advantage in this type of circuit is that water which has accidentally been spilled can be retained in one of the boundary dams, without the possibility of endangering the downstream users. From the assessment it appears that although the mining activities have influenced the water within the mining area this impact is only confirmed to certain areas. Biotic environmental conditions at certain sites resemble the conditions of the two control sites while other, notably those in contact with processing plants (e.g. metallurgical plant), are far more deteriorated. pH does not seem to be a problem at this specific mine. The main reasons are that the underlying geology of the mine is dolomitic in nature, while the sulphate concentration in the ore appears to be lower than those' found at the Witwatersrand mines. Case study Mine Three is situated in the Klerksdorp gold-mining region. The mine has a complex water circuit as a percentage of the service water is being reused or/and discharged via effluent streams into the Vaal River. Metal concentrations in the sediment core samples indicate a large variability between seasons, sites and depth. Sites in close proximity of slimes dams have high iron and manganese concentrations, whilst those in contact with effluent water from metallurgical plants have relatively high nickel, copper and in concentrations. This can be related to the type of processing material used in the gold-mining process.

The Kansanshi Cu-Au deposit located in the Domes region of the North West province of Zambia is characterised by structurally controlled high angle veins and associated alteration halos. The northwest trending Kansanshi antiform flanks the Solwezi syncline to the north and hosts the Kansanshi deposit and consists of tillites and metasedimentary rocks. Mineralisation is associated with Neoproterozoic Pan African deformation events experienced during the formation of the Lufilian fold belt; however recent findings confirm that structures in the form of reverse and normal faults and drag folds are critical controls on mineralisation within the deposit, Main pit in particular. Low angle faults occurring below the current pit are believed to have served as major fluid pathways during mineralisation. Age dating data from the Kansanshi deposit suggest that mineralisation took place between 512 and 503 Ma indicating that the event was associated with metamorphism. Two types of alteration are dominant within the Main pit (Kansanshi deposit) with the type and intensity of alteration being largely controlled by lithological units. Albite alteration occurs dominantly in phyllites and schists whereas dolomitisation is prevalent in calcareous units. Alteration is associated with mineralisation, and therefore is used as a condition for predicting vein or disseminated mineralisation. The high Au tenor at Kansanshi can be attributed to gold grains occurring in association with melonite (NiTe₂) and microfractured pyrite intergrown with chalcopyrite in sulphide and quartz dominated veins and veinlets. Analysis of gold grade distribution within the Main pit shows a clear concentration of the element along the major north-south trending structures like the 4800 and 5400 zones, possibly through supergene enrichment in the oxide-transition-sulphide zones. It is imperative that exploration for Kansanshi-type deposits will require geochemical and geophysical studies, understanding of the geology of an area to identify the three lithostratigraphic units (red beds, evaporites and reducing strata).

This study set out to evaluate the development potential of extractive sector corporate social investments (CSI) in Cameroon. It does this by evaluating the extent to which extractive companies effectively integrate CSI in their business operations and how this can be improved upon for more effective development outcomes in the country. The study premises that CSI can contribute to development but its activities will not always amount to just, balanced and sustainable development outcomes. To understand the extent to which it does, this study develops and applies a framework for determining the applicability and effectiveness of extractive sector CSI practices. The research followed an interpretivist philosophical orientation. A case study research strategy with the elements of a survey research was used. It also implemented a mixed research methods approach and relied on both primary and secondary data sources. The CSI evaluation process used documentary survey techniques and content analysis of corporate social responsibility-related documentation provided by extractive companies and other sector stakeholders. This was triangulated with an expert survey as well as a survey of major development organisations to understand the opinion of the external environment that should shape CSI practices. Results were analysed, discussed and synthesised using the front-end, mid-phase and back-end criteria for evaluating CSI integration. Findings show significant level of adherence to the discretionary idea of CSI among extractive firms working in Cameroon. This is due partly to growing social responsibility awareness among extractive firms around the world and the consequence of inaction. The greater majority of companies however, do not show strong proof of well thought out CSI implementation strategies. The feeling among experts is that extractive sector CSI in Cameroon is failing. It is predominantly self-regulated by extractive companies which raise questions regarding objective and credible CSI practices. The study concludes that CSI has been implemented in ad-hoc, haphazard and un-systematic ways. It has a viable potential to contribute to development but still suffers from a very weak CSI enabling environment as well as the challenges of sustainable development. Extractive sector CSI therefore, still needs to be significantly reworked to enhance its potential in contributing to just, balanced and sustainable development in Cameroon. It is recommended that an enabling environment be put in place through CSI promotional activities in the country.

The skills shortages in mining and mineral sector had existed for a decade and had a widespread effect on South Africa economy. It affects the level of economic productivity and reduces the country’s capacity to develop a knowledge society. This, in turn, affects the country’s functioning in the global economy. Despite the sector’s best efforts, the shortages continue to grow and threaten the delivery of projects and growth plans. Some researchers contend with the view that the persistence of skills shortages in mining and mineral sector is largely due to entrenched attitudes among both the industry and the community. They claim that employers have the means to change the educational profile of the subsectors by appointing recruits with higher levels of schooling. However, owing to the limited number of higher educated people living in the communities surrounding the mining operations and lack of interest in mining of people with higher levels of education, to name but few, employers are perceived to have a habit of employing people with little skills. The current study was aimed at investigating the impact of skills shortage on organisational performance, propensity to leave, competitive advantage and sustainability, from the management perceptive. The main objective of this study was to incorporate and embed previous research findings and theories into a comprehensive hypothetical model. A hypothetical model showed various factors that may influence skills shortage. Four independent variables (working environment, employment conditions, resources and education and training) were identified as variables that may influence skills shortage; and mediating variable (skills shortage) was also identified as a variable that have potential to affect dependent variables (organisational performance, propensity to leave, competitive advantage and sustainability) of gold mining sector. Furthermore, eight hypotheses were developed to test the relationship between independent, mediating and dependent variables. All these variables were clearly defined and operationalized with various items obtained from measuring instruments used in other similar studies. A purposive sample of 343 respondents was drawn from the population. A seven-point Likert scale and structured questionnaire were administered in person to the respondents and of which 300 were usable and subjected further to several statistical analyses. The validity and reliability of the measuring instrument was evaluated using significant effect p< = 0.001 and Pearson’s correlation test (α = 0.05). Data gathered were fed to and analysed by STATISTICA (version 10) and factor analysis and regression analyses were the statistical procedures used to test the significance of the relationships between the various independent and dependent variables. Consequently, working environment, resources and education and training were three independent variables that were identified as having ability to predict propensity to leave, competitive advantage and sustainability. An attempt was made to establish whether various demographic variables have an influence on mediating and dependent variables through the introduction of gender and position in the organisation while conducting an Analysis of Variance and Multiple linear regressions, but they obtained negative values. The conclusion is that demographic variables do not have over mediating and depended variables. The findings of this study states that with conducive working environment, availability of resources, the high levels of education and training, the country could produce skills that would reduce propensity to leave, drive competitive advantage and sustainability, innovation and entrepreneurship, create competitive advantages and boost employment sustainability.