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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Evaluation of the sustainability and environmental impacts of mining in the Rustenburg Region

Ololade, Olusola Oluwayemisi 05 November 2012 (has links)
Ph.D. / This study evaluates the environmental impacts of platinum mining in the Rustenburg region and the development of the region into a sustainable society, post the Johannesburg World Summit on Sustainable Development (WSSD) held in 2002. The region has been the location of intensive mining and metallurgical processing of platinum group minerals and chromium for more than three decades. Many studies have focused on the impacts of individual mines on their immediate environment and the sustainability of their operations. This study takes an holistic approach, looking at environmental changes across a larger area and the evaluation of the implementation of sustainable development principles in the region in the decade following the Johannesburg WSSD summit, using a multi-disciplinary approach. The debate concerning a suitable definition for sustainability within the mining context was followed through a literature review. In a strict sense, there is a paradox - mining is inherently unsustainable because of the finite, non-renewable nature of mineral resources. To resolve this paradox, two concepts of sustainability emerged: weak sustainability, in which economic capital replaces natural capital; and strong sustainability, prevention and minimising any environmental damage. These two concepts of sustainability were examined within the mining context, and the conclusion reached in this study is that the weak sustainability concept is more realistic and useful in the mining industry, since diverse environmental impacts cannot be avoided during mineral extraction. However, this does not mean that the environmental impacts should be neglected; instead they should be minimised. Sustainability is then achieved when the total amount of capital (i.e. both natural and economic) is constant or increases. Medium-resolution satellite data (Landsat and ASTER images) were used to map land cover/use to quantify the changes between 1973 and 2007, over 205 209 hectares of the Rustenburg region. The most important land cover/use change was the conversion of grassland to agricultural lands and mining areas. Changes in mine tailings storage facilities in terms of size and vegetation status were analysed. Landscape metrics (fragmentation index) were used to interpret the statistics derived from the land cover/use change to give an indication of the functioning of the ecosystem. Tailings samples were collected from two tailings storage facilities. Grain size analysis of the tailings samples was conducted to determine the percentage of particles with diameter ≤2.5 μm and ≤10 μm. Chemical analyses of samples were performed to determine elements of major concern because of their enrichment in the tailings and their potential toxicity. An analysis of the weather data acquired from the weather station located within the area was presented in the form of wind roses. Information on particle-size distributions obtained from the tailings samples and local meteorological data were used to carry out a detailed dispersion model of fugitive dust from mine tailings storage facilities.
32

Considerations for stope gully stability in gold and platinum mines in South Africa

Naidoo, Kumendrie 30 November 2005 (has links)
Gullies have been regarded as the "artery" in mining because they provide the only access route for material, people and ore in stopes. It thus becomes vital to provide the industry with suitable guidelines for gully layouts, geometry and the support required at all depths to keep the gully safe at all times. The research has indicated that best practices for gully layouts have been well recognised, but often poorly applied for many years. To address the issue of best gully practices, research was based on a review of past practices, underground visits, mine standards, codes of practice and the use of numerical modelling as a tool to back- analyse the underground conditions observed. The recommendations provided do not attempt to develop any new techniques for gully protection. They try to provide a guide for best practice under various geotechnical conditions. Based on depth, or stress environment, a broad based recommendation for gully geometry is provided. Using numerical modelling calibrated to underground observations, optimum widths and spans for each mining layout used at different depths are provided as a prescriptive guideline. • Sidings can only be omitted where stress damage does not occur. • A minimum siding width of 2m is recommended wherever sidings are cut. • Lagging sidings should be avoided and used only if absolutely essential. • In high stress areas gullies should be footwall lifted behind the stope faces or within wide headings. • All sidings must be cut on reef. Off reef sidings are not acceptable. • Correct blasting practice is essential to ensure stability of gully shoulders. • Gully width and span between support over gullies should be minimised. • Gullies must be kept straight. Excavation and cleaning of downdip sidings remains problematical from a practical mining point of view and future research is recommended in this area. / Dissertation (MSc (Mine Strata Control))--University of Pretoria, 2006. / Mining Engineering / unrestricted
33

Characterization of diesel emissions with respect to semi-volatile organic compounds in South African platinum mines and other confined environments

Geldenhuys, Genna-Leigh January 2014 (has links)
Concentrations of diesel particulate matter (DPM) and polycyclic aromatic hydrocarbons (PAHs) in platinum mine environments are likely to be higher than in ambient air due to the use of diesel machinery in confined environments. PAHs may be present in gaseous or particulate phases each of which have different human health impacts due to their ultimate fate in the body. The sampling of both phases was made possible by means of small, portable denuder sampling devices consisting of two polydimethylsiloxane multi-channel traps connected in series and separated by a quartz fibre filter. Thermal desorption coupled with two dimensional gas chromatography with mass spectrometric detection (TD-GCxGC-ToFMS) was employed to analyse samples from three different platinum mines. The underground environments revealed that PAHs were predominantly found in the gaseous phase with naphthalene and mono-methylated derivatives being detected in the highest concentrations ranging from 0.15 – 8.73 μg.m-3. Similarly higher gas phase PAH loading was found in the Daspoort Tunnel. The particle bound PAHs underground were found in the highest concentrations at the Load Haul Dump (LHD) vehicle exhaust with dominance of fluoranthene and pyrene and concentrations ranged from 0.52-109.60 ng.m-3. This work highlighted the need to characterise both gaseous and particulate phases of PAHs in order to assess occupational exposure and demonstrated the successful application of these portable denuders in the mining environment. / Dissertation (MSc)--University of Pretoria, 2014. / tm2015 / Chemistry / MSc / Unrestricted
34

The geology, geochemistry and silicate mineralogy of the upper criticial zone of the north-western Bushveld Complex, at Rustenburg Platinum Mines, Union Section

De Klerk, William Johan 20 March 2013 (has links)
Rustenburg Platinum Mines, Union Section, is located in the mafic phase of the north-western sector of the Bushveld Complex. This part of the Complex is characterised by transgressions of Upper zone ferrogabbros across the lower sequence of mafic rocks. These transgressions have effectively isolated a roughly triangular segment of Lower, Critical and Main zone rocks. It is in the upper part of the Critical zone that the Merensky Reef, with a strike length of 9,5 km, is found to suboutcrop below a 2-3 m black turf soil cover and it constitutes the orebody being mined at Union Section. Underground mining and development have exposed a stratigraphic succession from the Middle Group chromitites to within the lower part of the Main zone gabbros. A detailed investigation of a 100 m stratigraphic succession was undertaken in the upper part of the Critical zone, which includes the Bastard Reef, Merensky Reef, Pseudo Reef, UG 2 and UG 1 layers. Stratigraphic descriptions are presented for both a normal and potholed succession, as well as a description of pothole characteristics. The variations of Merensky Reef thickness, pothole distribution and structure of the are body are also discussed. Forty seven whole-rock major- and trace-element analyses were carried out on selected samples from both normal and potholed successions, although more emphasis was placed on the former. These samples were taken from just below the UG 1 to above the Bastard Reef. Trace elements determined included Sr, Rb, Y, Nb, Zr, Cr, Co, Ni, Cu and V. The cyclical nature of the layering is clearly defined by breaks in the trends of both the major- and trace element analyses, although some elements are strongly influenced by the modal proportions of the mai n mineral phases. Although major breaks are observed for individual elements , insignificant variation of the Mg/Mg+Fe 2 + ratio is observed throughout. New electron microprobe data are presented for the main silicate phases olivine , orthopyroxene, clinopyroxene and plagioclase , while only a limi ted number of analyses were carried out on the spine l phase. There would appear to be a reversal of the expected fractionation trend from the hanging wal l of the UG 2 to the Pseudo Marker layer. There is an upward increase of the Fo content of the olivine from F0₇₆ , ₇₋₈₁,₆ . A similar trend is observed for the orthopyroxene analyses . The Merensky unit, as a whole, exhibits a gradual decrease in the Mg end member of the Ca-poor pyroxenes from En ₇₈,₅₋₇₄ . was found to be markedly more calcic Cumulus plagioclase (An ₇₂, ₈-₈₁, ₇) than the intercumulus phase (An₅₆,₃₋₇₁, ₉) ' A further feature of the cumulus plagioclase is that strong zonation was observed with the cores of individual crystals being consistently lower in Ca relative to their margins . / KMBT_363 / Adobe Acrobat 9.53 Paper Capture Plug-in
35

Determinants of employment in the Platinum mining industry in South Africa

Khoza, Nyiko January 2017 (has links)
Thesis (M. Com. (Economics)) -- University of Limpopo, 2017 / The study intends to investigate the determinants of employment in the platinum mining industry in South Africa. Employment levels decreased dramatically in the platinum mining industry in South Africa. This is due to decrease in export demand for platinum, high operating cost, labour unrest, low levels of production and other determinants of employment. The specific objective of the study is to determine the nexus between employment, output, domestic demand and export demand. Annual time series data covering the period between 1992-2013 was used. The study employed the Vector Error Correction Model approach. Johansen Cointegration test results confirmed the existence of a long run relationship amongst variables under investigation. Export demand and output are found to be positively related with employment. The speed of adjustment to equilibrium is -0.283202. Impulse response functions and variance decomposition are also generated to explain the response to shock amongst variables. The results of the study vindicate that the platinum mining industry should implement policies and strategies to increase output which will lead to higher levels of employment as well as economic growth. In addition, government should also create a conducive environment to enable the industry to expand and the industry should also intensify its export drive, these findings are envisaged to contribute significantly to the existing but limited literature on the subject under investigation. / National Research Foundation
36

The design of a disaster prevention centre for Modikwa Platinum Mine in Burgersfort.

Lourens, Philippus Jacobus. January 2012 (has links)
Thesis (MTech. degree in Architecture: Professional)--Tshwane University of Technology, 2012. / The aim of this thesis is to design a Disaster Prevention Centre for the platinum mining sector which will save lives and aid in the South African Department of Mineral and Resources' campaign towards "zero fatalities" within the mining industry. The facility is intended to be a prototype for the preventative training of platinum miners around the world by examining past, present and predicted future mining incidents and using this information to create a safe simulated learning environment or mock-up scenario of possible mining hazards.
37

Assessment and management of the impact of platinum mining on water quality and selected aquatic organisms in the Hex River, Rustenburg Region, South Africa

Gumede, Sabelo Victor 02 November 2012 (has links)
Ph.D. / Mining operations significantly influence the environment due to direct and indirect discharges of waste products into the aquatic systems. The primary aim of this study was to assess the current situation in the platinum mining area and develop a management plan to ensure that existing and potential environmental impacts caused by platinum mining and processing are mitigated. To do this, an assessment was carried out to investigate changes in critical aquatic invertebrate and fish community distributions and assess how they relate to measured environmental factors. Five sites were selected, one reference site which is upstream of heavy mining activities and four sites within heavy mining and processing activities. Standard techniques for water, sediment, invertebrate and fish sampling were used. Macro-invertebrates sampled were identified to family level whereas fish were identified to species level. Multivariate analysis used was cluster analysis by non-metric multidimensional scaling (NMDS) for both macro-invertebrates and fish. Three methods of ordination were used to analyze the biotic and abiotic data namely N-MDS, Correspondence Analysis (CA) and Canonical Correspondence Analysis (CCA). Cluster analysis of macro-invertebrates data revealed three major groups based on sampling period (low flow or high flow) and the last cluster according to the locality. Multidimensional scaling ordination of high and low flow for macro-invertebrate communities confirmed the groupings detected by cluster analysis. Cluster analysis for fish communities revealed two groups at 50% similarity; the first group is the combination of reference and exposure sites for both high and low flow sampling regimes. No fish were sampled at site 4 during both low and high flow regimes. Multidimensional scaling ordination of high and low flow fish communities confirmed the groupings detected by cluster analysis. Analysis using a similarity profile (SIMPROF) test indicated that fish communities are statistically (p=5%) the same. It was found that macro-invertebrates and fish respond differently to environmental variables.
38

Petrogenesis of the upper critical zone in the Western Bushveld Complex with emphasis on the UG1 Footwall and Bastard units

De Klerk, William Johan January 1992 (has links)
This study is an account of the stratigraphic sequence, the petrography, mineralogy (microprobe investigations of orthopyroxene, clinopyroxene, olivine and plagioclase feldspar), and whole-rock major- and traceelement geochemistry of the silicate cumulates of the Upper Critical Zone in the western Bushveld Complex. Two parts of the study - an investigation of a 350m column incorporating the MG3 and UGI Footwall Units, and a comparison of two additional Upper Critical Zone profiles with a previously compiled profile between the UGI and Bastard Units - are focused on RPM Union Section in the northwestern sector of the Complex. The third part is a detailed vertical and lateral investigation of the Bastard Unit at the top of the Critical Zone, which draws on sampling and data compilation from seventeen profiles in the western limb of the Complex. The MG3 Unit (45m) is made up of a lower chromitite layer overlain by a norite-pyroxenite-anorthosite sequence while the UGlFW Unit (295m) is composed of a related series of lower chromitite layers (MG4) overlain by a pyroxenite-norite-anorthosite sequence capped by the UGI chromitite layer. These mafic cumulates display a distinctive pattern of oscillating cryptic variation in whole-rock Mg/(Mg+Fe), FeO/Ti0₂, Cr/Co and Ni/V ratios through the sequence. Sympathetic oscillations are recorded for compositions of orthopyroxene and plagioclase feldspar and eight subcycles are recognised through the UGlFW Unit. The entire sequence is characterised by the presence of small, spheroidal, embayed and irregularly shaped plagioclase grains which are poikilitically enclosed in cumulus orthopyroxene grains of both pyroxenites and norites. This texture is indicative of partial resorption of pre-existing feldspar primocrysts within the melt prior to their being incorporated into the host orthopyroxene grains. Textural, geochemical and isotopic data suggest that this sequence was built up by periodic additions of fresh, relatively primitive liquid into fractionated resident liquid, and subsequent mixing within the magma chamber. The Bastard Unit sequence, described in Chapter 4, is the last and most complete cyclic unit (c. 60m) of the Critical Zone, and its upper contact defines the boundary between the Critical and Main Zones of the Complex. This Unit can conveniently be sub-divided into a lower part, where orthopyroxene occurs as a cumulus phase, and the upper part which is composed entirely of anorthosite (Giant Mottled Anorthosite). The basal part of the Unit (≤ 18m) comprises a thin chromitite layer < O.5cm) overlain by a pyroxenite-melanorite-norite-leuconorite sequence. The basal pyroxenite is orthocumulate in character and rapidly gives way to norites and leuconorites. A distinct threefold subdivision emerges within the Giant Mottled Anorthosite which is predominantly an adcumulate which becomes orthocumulate in character at its top. Apart from minor deviations in thicknesses these lithologies are recorded over the entire strike-length covered in this study. Profiles of cryptic variation are compiled for orthopyroxene, plagioclase and whole-rock data and show that the Bastard Unit displays a characteristic pattern which is maintained throughout the western Bushveld Complex. A minor yet distinctive reversal in cryptic variation is revealed at a level which is stratigraphically variable within the lower Giant Mottled Anorthosite, and results in a double cuspate pattern. A remarkable feature of the basal Bastard pyroxenites is that although the modal proportion of mafic to felsic constituents varies systematically away from the northwestern sector, the Mg/(Mg+Fe) ratio of orthopyroxenes remains constant at 0.804 over a lateral strike distance of 171km. Within the upper part of the Unit the orthopyroxene is markedly Fe-rich and it is here that inverted primary pigeonite appears for the first time as a cumulus phase. In addition, K-feldspar, oscillatory zoned plagioclase grains and high levels of incompatible trace elements are noted at this level. On the basis of the data presented it is concluded that the Bastard Unit represents the crystallisation of a final, relatively large influx of hotter primitive liquid, with upper Critical Zone affinities, and subsequent mixing with a column of cooler (less dense) supernatant liquid which had in part hybridized with the overlying Main Zone magma. It is hypothesised that this new liquid was emplaced as a basal flow beneath supernatant liquid and that it initiated the deposition of mafic cumulates at its base. The supernatant liquid is interpreted as representing the fractionated residuum produced by crystallisation of earlier cyclic units, with plagioclase on the liquidus, and that it contained an abundance of small plagioclase primocrysts in suspension. Development of the Unit can be viewed as a two-stage process. In the lower half of the unit, chemical and physical parameters typical of the new magma dominated the crystallisation process, and resulted in cumulates very similar to other relatively complete Upper Critical Zone units. In the upper, leucocratic sequence, above a minor reversal, crystallisation was from a liquid which was the product of mixing of a minor pulse of primitive liquid with the reservoir of hybridized supernatant liquid. Although the Bastard Unit is not continuous around the entire Western limb of the Complex, it is concluded that it developed in a single, or connected, magma chamber and that its irruptive feeder zone was located in the proximal northwestern facies of the Complex.
39

Investigation into the technical feasibility of biological treatment of precious metal refining wastewater

Moore, Bronwyn Ann January 2013 (has links)
The hydrometallurgical refining of platinum group metals results in large volumes of liquid waste that requires suitable treatment before any disposal can be contemplated. The wastewater streams are characterized by extremes of pH, high inorganic ion content (such as chloride), significant residual metal loads and small amounts of entrained organic compounds. Historically these effluents were housed in evaporation reservoirs, however lack of space and growing water demands have led Anglo Platinum to consider treatment of these effluents. The aim of this study was to investigate whether biological wastewater treatment could produce water suitable for onsite reuse. Bench-scale activated sludge and anaerobic digestion for co-treatment of an acidic refinery waste stream with domestic wastewater were used to give preliminary data. Activated sludge showed better water treatment at lab scale in terms of removal efficiencies of ammonia (approximately 25%, cf. 20% in anaerobic digestion) and COD (70% cf. 43% in digestion) and greater robustness when biomass health was compared. Activated sludge was consequently selected for a pilot plant trial. The pilot plant was operated on-site and performed comparably with the bench-scale system, however challenges in the clarifier design led to losses of biomass and poor effluent quality (suspended solids washout). The pilot plant was unable to alter the pH of the feed, but a two week maturation period resulted in the pH increasing from 5.3 to 7.0. Tests on algal treatment as an alternative or follow-on unit operation to activated sludge showed it not to be a viable process. The activated sludge effluent was assessed for onsite reuse in flotation and it was found that there was no significant difference between its flotation performance and that of the process water currently used, indicating the effluent generated by the biological treatment system can be used successfully for flotation. Flotation is the method whereby minerals refining operations recover minerals of interest from ore through the addition of chemicals and aeration of the ore slurry. Target minerals adhere to the bubbles and can be removed from the process.
40

The geometallurgical characterization of the Merensky Reef at Bafokeng Rasimone Platinum Mine, South Africa

Smith, Albertus Johannes Basson 08 October 2014 (has links)
Ph.D. (Geology) / Please refer to full text to view abstract

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