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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.
231

Log structures : criteria for their description, evaluation and management as cultural resources

Glover, Margaret L. 01 January 1982 (has links)
This thesis discusses mining cabin sites from the nineteenth and early twentieth centuries as cultural resources. Special attention is given the concept of "description" in regards to discussion of the resource category, history, and physical attributes of the sites. Evaluation and management suggestions are presented for this particular resource category. To aid in the process of identification of log cabin notching, a typology of notches is developed and presented within the context of the thesis.
232

The stratigraphy, structure, and gold mineralization of the Jamestown and Sheba Hills areas of the Barberton Mountain Land

Anhaeusser, C. R. (Carl Robert) 28 May 2015 (has links)
No description available.
233

Reproductive toxicity and bioavailability of arsenic in contaminated artificial and natural soils using the earthworm

Wong, Stephen W. January 2003 (has links)
No description available.
234

Law enforcement in the South African Gold Mining sector : the nexus between company, environmental and equity law

Lombard, Dewan 08 1900 (has links)
Although the mining industry contributed to the development of the country by providing infrastructure and employment, it left a negative impact on the environment. To this end, various pieces of law were promulgated to limit environmental damage and hold those who pollute (Mining Companies / licensees) accountable. This research focused on two study sites namely Blyvooruitzicht and Grootvlei gold mines. Both mines underwent forced mine closure and their environmental liabilities remained unresolved. This study focused on important laws governing the South African gold mining sector, to form an understanding of these laws and to establish if these laws protect the environment sufficiently or not. The study included an overview of the current relevant legislative framework regarding mines, with the aim of identifying if there were gaps between Mining law, Company law, B-BBEE law (Equity Law) and Environmental law. This included an exploration of the interrelationships between the various pieces of legislation and the challenges relating to compliance and enforcement of these mentioned laws. Further to this, the research study investigated the requirements and responsibilities of the South African State, and directors of mining companies. The finding was that South African law with respect to mining companies needs minor adjustments, but the crux of the problem is a lack of effective implementation and enforcement by the State. There is ineffective administration of environmental quality control by the various designated National Government Departments. Recommendations made include the need for clear monitoring of compliance and enforcement of the environmental regulatory framework if there is to be successful mine closure in South Africa. In addition, the South African State Government could consider incentivizing compliance, that is, reward mining companies who uphold environmental law. Further to this the thesis suggest the elimination of any contradictions between the various legislations within the mining industry and stipulates that legislation must be read in conjunction with one-another if a robust legislative framework is to exist. / Environmental Sciences / M.Sc. (Environmental Science)
235

The contribution of leadership behaviour in creating a safety conscious organisational culture : a case study of Anglo American mining operations

McLeod, Ashley 12 1900 (has links)
Thesis (MBA (Business Management))--Stellenbosch University, 2008. / ENGLISH ABSTRACT: In the 20th century, many employees in the South African mining industry were involved in occupational accidents which either resulted in personal injury or had fatal consequences. Despite the introduction of numerous industrial safety programmes to prevent fatal incidents and minor injuries, the South African mining industry death toll remains consistently high, at approximately 200 employees per annum. The trend of employee injury and death continues unabated into the new millennium. This safety performance has been met with growing dissatisfaction in the ranks of government, worker unions, employees and business stakeholders. This dissatisfaction is directed at chief executives who are being blamed for the occupational accidents on their mines. There is now growing focus on the leadership of mining companies and how it contributes to shaping an organisational culture for improved safety performance. The researcher examines whether leadership is a key component in creating a safety conscious organisational culture, and uses literature studies and the Anglo American mining company as a practical case study to support the investigation. Anglo American, listed on the Johannesburg and London stock exchanges is the largest mining company in South Africa and also one in which many fatal injuries have occurred; providing an abundance of safety information. The researcher reviews previous literature studies and explains the journey Anglo American undertook to improve its safety performance since listing on the London Stock Exchange in 1999. The concepts of organisational culture, safety culture, leadership and organisational performance, are discussed from a theoretical and practical perspective using literature studies. These are then examined with the ultimate view of understanding their practical impact on organisational safety as espoused in the literature. The literature provides a broad framework on which to assess Anglo American's safety journey from 1999 to the end of 2007. This journey details the safety programmes and efforts employed by Anglo American to eliminate fatalities and injuries and also highlights the impact of the organisation's leadership on the safety performance of the company. It is concluded that the contribution of leadership is pivotal to establishing a safety-conscious organisational culture and that specific behaviours from executives, senior managers, middle managers, supervisors and workers are needed to develop an organisations safety culture for improved safety performance. / AFRIKAANSE OPSOMMING: Gedurende die 20ste eeu was baie werkers in die Suid-Afrikaanse mynbedryf betrokke in beroepsverwante ongelukke wat tot persoonlike beserings of lewensverlies gelei het. Ten spyte van die instelling van veelvuldige beroeps-veiligheidsprogramme om noodlottige insidente en ander minder ernstige beserings te voorkom, bly die dodetal in die Suid-Afrikaanse mynbedryf konstant hoog, teen ongeveer 200 werkers per jaar. Hierdie tendens van dood en beserings onder werkers gaan ongetem voort tot in die nuwe millennium. Hierdie veiligheidsrekord word met toenemende ontevredenheid deur die regering, werkers-vakbonde, werkers en bedryfsinsethouers beskou. Hierdie ontevredenheid word gemik op uitvoerende bestuur, wie blameer word vir beroepsverwante ongelukke in hul myne. Daar word dus toenemend gefokus op die leierskap van mynmaatskappye en hoe dit bydra tot die skepping van 'n organisasiekultuur van verbeterde veiligheidsuitslae. Die navorser ondersoek die vraag of leierskap 'n kern komponent is in die daarstelling van 'n veiligheids-bewuste organisasiekultuur, en maak gebruik van literatuurstudies sowel as Anglo American mynmaatskappy as 'n praktiese gevallestudie om sy ondersoek te ondersteun. Anglo American is die grootste mynmaatskappy in Suid-Afrika en ook die een waar baie noodlottige ongelukke voorgekom het, en dus 'n groot bron van veiligheidsinligting kan voorsien. Die navorser hersien teoretiese literatuurstudies en verduidelik dan die optrede van Anglo American om sy veiligheidsrekords te verbeter sedert sy noteering op die Londonse Effektebeurs in 1999. Die konsep van organisasiekultuur, veiligheidskultuur, leierskap en organisasieprestasie, word bespreek vanuit 'n teoretiese en praktiese perspektief met behulp van literatuurstudies en hierdie word bestudeer met die uiteindelike doel om die praktiese impak daarvan in industrie te verstaan soos uiteengesit in die literatuur. Die literatuur voorsien 'n breë raamwerk waarteen Anglo American se veiligheidstog gemeet kan word vanaf 1999 tot einde 2007. Hierdie tog verskaf detail van hoe Anglo American veiligheidsprogramme gebruik het om noodlottigge ongelukke en beserings uit te skakel en beklemtoon ook die impak van die organisasie se leierskap op die veiligheidsrekord van die maatskappy. Die gevolgtrekking word gemaak dat die bydrae van leierskap kern is tot die daarstelling van 'n veiligheidsbewuste kultuur en dat spesifieke optredes van hoofbestuurders, seniorbestuurders, middelvlakbestuurders, opsieners en werkers nodig is om 'n veiligheidskultuur te bewerkstellig om veiligheid in maatskappye te verbeter.
236

Functional evaluation of a gold mine tailings rehabilitation project

10 June 2011 (has links)
Msc. / This study focuses on the functional evaluation of a gold Tailings Storage Facility (TSF), the Fleurhof TSF (designated slimes dam 2L3), which is representative of gold slimes (tailings) dams in the Witwatersrand. The aim is to evaluate the rehabilitation status (in terms of species composition and landscape function) of TSF surfaces that were planted ~20 to ~40 years ago using the most common rehabilitation practice, namely pasture grassing. Pasture grassing aims to obtain rapid dust control. Mine closure was not considered at the time, and the vegetation was hence not designed with ecological processes or long-term objectives in mind. However, over time, grassing practices became routine in the TSF vegetation industry, and the contribution that they have made towards surface rehabilitation needs to be assessed against the current site closure objectives. On the selected site, evaluations of vegetation cover, species composition, and substrate physical and chemical properties were conducted in 1975 (Thatcher, 1979). The aim of the current mid-summer study in 2009 was addressed by assessing the same parameters of vegetation cover, species composition, and soil physical and chemical properties, and comparing these to the results of the previous assessment in 1975. Landscape Function Analysis (LFA – an index-based method of evaluating the retention of resources by surfaces and soil condition), was applied to determine the landscape function (stability, infiltration and nutrient cycling that are derived from the eleven soil surface assessment indicators), and compared with the landscape function of natural analogues in the same locality. Landscape organisation (also an indicator of LFA) was used to investigate the contribution of vegetation overall, and of discrete plant functional groups to landscape functionality. A total of 35 plant species were observed in the quadrats (56 species on the TSF overall), with 51% of species overall being alien. Perennial vegetation and cryptogam covers contributed the most to stabilising the TSF slopes and flat (top) surfaces. The percentage of vegetation basal cover on the TSF (30% – 70%) was lower than for analogue grassland sites on a nearby hill (80% – 100%). Lower basal vegetation cover on the TSF than on the analogue site, were associated with lower LFA indices of stability on all TSF slope aspects (P = 8.19 x 10-13 for all aspects), iii lower nutrient cycling for the northern and southern TSF slopes (south aspect P = 4.20 x 10-6; top aspect P = 0.03), and lower infiltration on the southern slope of the TSF (P = 2.68 x 10-6). However, a higher infiltration on the northern TSF aspect (P = 0.02) than on the analogue site, was attained. Perennial tussock grass patch types (which included perennial forbs) made the largest contribution to the soil surface assessment (SSA) indicators on the TSF and analogue sites, and therefore to the LFA indices that were derived from these SSA indicators. The contribution of woody patches to function was not evaluated.
237

Assessment of the national DSM potential in mine underground services / M. den Boef

Den Boef, Martinus January 2003 (has links)
ESKOM is moving towards a price structure for electricity which reflects, as far as possible, the real cost of generation. It is called real time pricing (RTP). ESKOM developed this cost structure to coax customers to use more electricity in off-peak periods (low cost of generation) and less electricity in peak periods (high cost of generation). However, many industries do not effectively use these price offerings from ESKOM to the detriment of themselves and ESKOM. In previous research improvements to this situation for the South African mining industry were investigated. ESKOM funded research to find the potential for load shifting on mines using RTP. The RTP investigation focused on the supply side management (SSM) in the mining context of underground services on gold and platinum mines. Elements investigated included the ventilation, cooling and pumping (VCP) systems. (Except for pumps, these plants are generally installed aboveground.) Previous research showed a national RTP and SSM potential to shift 500 MW of electrical load for a period of 5 hours. Through the previous research it became clear that the mines were previously able to react partially to the price signals. However, it was proved by the research that the full load shift potential can only be realised through the use of integrated dynamic simulation and optimisation. An even higher potential exists for load shift and electricity efficiency through demand side management (DSM) on the underground services. Therefore, if underground DSM strategies are combined with SSM strategies, a further and much bigger potential can be exploited to the benefit of ESKOM and the mines. Due to these factors this study was undertaken. Three case study mines were identified for this study. They are Kopanang and Target, both gold mines, and Amandelbult, a platinum mine. The DSM potential on each of these mines was calculated using simulation, calibration, verification and optimisation. These results were presented to mine management to negotiate the implementation of the proposed strategies on one of the mines. Kopanang's management agreed to the implementation of these strategies for a trial period of 3 months after which the success would be evaluated. The results of the implementation, together with the case study results, were used to calculate the national DSM potential in the mining sector through extrapolation. The DSM potential amounts to 650 MW of load per day as well as 5% on electricity consumption. This amounts to a potential saving of R72.1 million per year using current tariffs. This means that ESKOM can save about R5000 million on the building of a new power station to supply the equivalent load to the DSM potential. Now that the national impact has been calculated and discussed, all these findings must be used to motivate the implementation of these strategies throughout the mining sector. A similar project can be undertaken to look at possible DSM strategies in the industrial sector. This might prove to be more difficult as the electricity intensive systems are mostly all linked to the final production. In the mind of management this out-weighs the possible cost savings that can be achieved. ESKOM and the NER will have to rethink their strategy. Through DSM and load shifting actions alone the pending electricity crisis will not be averted. The current tariff structures should be amended to not only reflect the true cost of electricity but also provide incentive for DSM and load shifting. Another problem that must be addressed to achieve the DSM targets set for 2007 is the time that it takes to complete the study as well as the implementation time. Software can easily be created to help in the speeding up of the case study itself, as the process and steps followed, as well as models used, are very generic (at least in the gold and platinum mining sector). / Thesis (Ph.D. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2004.
238

Assessment of the national DSM potential in mine underground services / M. den Boef

Den Boef, Martinus January 2003 (has links)
ESKOM is moving towards a price structure for electricity which reflects, as far as possible, the real cost of generation. It is called real time pricing (RTP). ESKOM developed this cost structure to coax customers to use more electricity in off-peak periods (low cost of generation) and less electricity in peak periods (high cost of generation). However, many industries do not effectively use these price offerings from ESKOM to the detriment of themselves and ESKOM. In previous research improvements to this situation for the South African mining industry were investigated. ESKOM funded research to find the potential for load shifting on mines using RTP. The RTP investigation focused on the supply side management (SSM) in the mining context of underground services on gold and platinum mines. Elements investigated included the ventilation, cooling and pumping (VCP) systems. (Except for pumps, these plants are generally installed aboveground.) Previous research showed a national RTP and SSM potential to shift 500 MW of electrical load for a period of 5 hours. Through the previous research it became clear that the mines were previously able to react partially to the price signals. However, it was proved by the research that the full load shift potential can only be realised through the use of integrated dynamic simulation and optimisation. An even higher potential exists for load shift and electricity efficiency through demand side management (DSM) on the underground services. Therefore, if underground DSM strategies are combined with SSM strategies, a further and much bigger potential can be exploited to the benefit of ESKOM and the mines. Due to these factors this study was undertaken. Three case study mines were identified for this study. They are Kopanang and Target, both gold mines, and Amandelbult, a platinum mine. The DSM potential on each of these mines was calculated using simulation, calibration, verification and optimisation. These results were presented to mine management to negotiate the implementation of the proposed strategies on one of the mines. Kopanang's management agreed to the implementation of these strategies for a trial period of 3 months after which the success would be evaluated. The results of the implementation, together with the case study results, were used to calculate the national DSM potential in the mining sector through extrapolation. The DSM potential amounts to 650 MW of load per day as well as 5% on electricity consumption. This amounts to a potential saving of R72.1 million per year using current tariffs. This means that ESKOM can save about R5000 million on the building of a new power station to supply the equivalent load to the DSM potential. Now that the national impact has been calculated and discussed, all these findings must be used to motivate the implementation of these strategies throughout the mining sector. A similar project can be undertaken to look at possible DSM strategies in the industrial sector. This might prove to be more difficult as the electricity intensive systems are mostly all linked to the final production. In the mind of management this out-weighs the possible cost savings that can be achieved. ESKOM and the NER will have to rethink their strategy. Through DSM and load shifting actions alone the pending electricity crisis will not be averted. The current tariff structures should be amended to not only reflect the true cost of electricity but also provide incentive for DSM and load shifting. Another problem that must be addressed to achieve the DSM targets set for 2007 is the time that it takes to complete the study as well as the implementation time. Software can easily be created to help in the speeding up of the case study itself, as the process and steps followed, as well as models used, are very generic (at least in the gold and platinum mining sector). / Thesis (Ph.D. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2004.
239

Monitoring rehabilitation success using remotely sensed vegetation indices at Navachab Gold Mine, Namibia

Bell, Maria Aletta 12 1900 (has links)
Thesis (MA)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Remote sensing and vegetation indices were evaluated for its usefulness to monitor the success of the rehabilitation programme of the decommissioned tailings storage facility (TSF1) of the Navachab Gold Mine, Karibib, Namibia. The study aimed to objectively illustrate the rehabilitation progression from tailings (baseline) to soil (capping) and vegetation (planted as well as natural). Baseline data sets of 2004 and 2005 were compared with imagery of 2009, 2010 and 2011. All the images were subjected to panchromatic sharpening using the subtractive resolution merge (SRM) method before georegistration. As no recent accurate topographical maps were available of the study area, the May 2010 image was used as a reference image. All other images were georegistered to this image. A number of vegetation indices (VIs) were evaluated. The results showed that the normalised difference vegetation index (NDVI) and the transformed vegetation index (TVI) provided the most promising results. Although the difference vegetation index (DVI) and enhanced vegetation index (EVI) distinguished the vegetation, rock, and soil classes, it was not as successful as the other VIs in classifying the rain water pond. TVI and NDVI were further evaluated for their efficacy in detecting changes. This was done by generating a series of change images and by qualitatively comparing them to false colour images of the same period. Both the NDVI and TVI delivered good results, but it was found that the TVI is more successful when water is present in the images. The research concludes that change analyses based on the TVI is an effective method for monitoring mine rehabilitation programmes. / AFRIKAANSE OPSOMMING: Afstandswaarneming en plantegroei-indekse is ge-evalueer vir die gebruikswaarde daarvan om sukses van die rehabilitasieprogram vir die geslote slykdam of tailings storage facility (TSF1) van die Navachab Goudmyn, Karibib, Namibië vas te stel. Die studie se doelwit was om die progressie in die rehabilitasie van slyk (basislyn) na grond (dekmateriaal) en plantegroei (aangeplant en natuurlik) te illustreer. Basislyndatastelle 2004 en 2005 is vergelyk met 2009, 2010, en 2011 beelde. Al die beelde is panchromaties verskerp deur die subtractive resolution merge (RSM) metode voor georegistrasie uit te voer. Aangesien geen onlangse, akkurate topografiese kaarte van die studiegebied beskikbaar was nie, is die beeld vir Mei 2010 as ‘n verwysingsbeeld gebruik. Al die ander beelde is op die laasgenoemde beeld gegeoregistreer. Die resultate het gewys dat die normalised difference vegetation index (NDVI) en die transformed vegetation index (TVI) die mees belowende resultate lewer. Al het die difference vegetation index (DVI) en enhanced vegetation index (EVI) goed onderskei tussen plantegroeiklasse en grond- en gesteentesklasse was dit nie so suksesvol met die klassifikasie van die reënwaterpoel nie. TVI en NDVI is verder geëvalueer vir effektiwiteit om verandering waar te neem. Dit is gedoen deur ‘n reeks van veranderingsbeelde te skep en dit dan kwalitatief met die valskleur-beelde vir dieselfde tydperk te vergelyk. Beide die NDVI en TVI het goeie resultate gelewer, maar die TVI was meer suksesvol om beelde met water te klassifiseer. Die navorsing lei tot die gevolgtrekking dat veranderingsanalises met die TVI ‘n effektiewe metode vir die monitoring van rehabilitasie programme is.
240

Geochemical characterisation of gold tailings footprints on the Central Rand Goldfield

Netshiongolwe, Khathutshelo Emmanuel 05 1900 (has links)
Gold mining in the Witwatersrand Basin of South Africa has resulted in soil contamination due to the lack of sufficient environmental management plans for the tailings dumps and remnant footprints. Tailings reclamation as a strategy of reducing pollution in the Central Rand, for instance, has resulted in contamination of water systems by acid mine drainage (AMD). After removal of the tailings dumps, remnant material is left over on the tailings footprints and these contain significant amounts of pollutants that were initially in the tailings. Heavy rainfall during summer dissolves primary minerals and later in the dry season, secondary minerals are precipitated as efflorescent crusts on and nearby tailings dumps as well as footprints due to high evaporation. The efflorescent crusts can redissolve when it rains and form acidic, metal and sulphate-rich solutions due to their soluble characteristics. This study aimed to characterise tailings footprints in areas targeted for human settlements and office spaces to assess their potential to release left over toxic elements such arsenic (As), lead (Pb), copper (Cu) and zinc (Zn). The approach to the study involved characterisation of oxidised and unoxidised tailings material and secondary precipitates on both tailings dumps and footprints. This involved determining the mineralogical composition using Powder X-ray Diffraction (PXRD). Dissolution and leaching studies were also conducted on the material followed by determination of constituent elements using inductively coupled plasma optical emission spectroscopy (ICP-OES) and sulphates using ion chromatography (IC). The leaching solutions used included rainwater; dilute sulphuric acid at pH of 3.0 (a common leachate in such acidic soils); as well as plant exudates such as oxalic and citric acids. The leachate solutions were used to correlate the mineralogical composition of secondary precipitates and tailings footprints. Potential implications on humans following any accidental ingestion of the tailings or contaminated soils were assessed using gastric juices. The ecological risk factors and risk index together with the model to evaluate daily intake and different pathways to humans were used to assess the toxicity caused by exposure to contaminants in the materials. The experimental work was augmented by computer simulations based on geochemical modelling (using the PHREEQC geochemical modelling code) to determine the speciation of elements (and thus their potential lability and bioavailability), dissolution and formation of secondary mineral precipitates in the tailings dumps and footprints. The findings of the PXRD study showed that the mineralogy of the tailings and footprints was dominated by quartz (SiO2) and some minor minerals such as pyrite (FeS2), pyrophyllite (Al2Si4O10(OH)2), chlorite (Mg,Fe)3(Si,Al)4O10), mica (K(Mg,Fe)3 AlSi3O10(F,OH)2) while that of secondary precipitates was dominated by jarosite (KFe3+ 3(OH)6 (SO4)2), goethite (FeOOH), melanterite (FeSO4.7H2O) and gypsum (CaSO4.2H2O). Minerals obtained for the secondary precipitates were corroborated by geochemical modelling. Leaching results using rainwater with pH ranges from 3.5 to 3.9 showed that trace elements are released very slowly from tailings dumps and footprints and in small concentrations during rainy seasons as follows: As (1.5 mg/L-4.5 mg/L), Pb (3.5 mg/L-5.5 mg/L), Cu (4 mg/L-4.8 mg/L) and Zn (23 mg/L-44 mg/L). The release and mobility of Cu, Pb, Zn and As occurs quite markedly when secondary precipitates dissolve, making the immediate impacted environment unfavourable for plant growth and any habits in the vicinity. This was substantiated by simulated dissolutions and assessment of the resulting elemental speciation that pointed to the elements being distributed in bioavailable forms, implying potential uptake by plants (such as vegetables that may be cultivated on such impacted soils). The model was used to evaluate the daily intake and different exposure pathways and the results showed that children may daily intake 48.4 mg kg-1 day-1 and adults‟ 32.8 mg kg-1 day-1 . After 5 years (1825 days) of exposure more harm may be experienced and findings shows that kids are the most victims on these contaminated sites compared to adults. Both children and adults may absorb low levels of these toxic elements daily and after long time of exposure it may cause disease like cancer in their body which may lead to death. Pathways may be through inhalation and accidentally ingesting tailings soil that contain toxic elements. Drawing from the above findings, it will be important that tailings footprints that have been earmarked as land for development (residential or office space) be thoroughly assessed for potential release of toxic elements and high levels of acidity. Further reclamation aimed at reducing these hazards can then be implemented. / College of Agriculture and Environmental Sciences / M. Sc. (Environmental Science)

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