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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.
161

A hydrogeological investigation of the Grootegeluk mine

Johnstone, Andrew Clifford January 1989 (has links)
The study concerns an assessment of the hydrogeological impact of an open cast coal mine in the North Western Transvaal Province of South Africa. The hydrogeological impact of the mine is assessed in terms of groundwater quality and levels. A monitoring system was installed to enable the present and future impact of mining operations on the hydrogeological regime to be assessed. Grootegeluk Mine is situated in the Waterberg Coal Field of South Africa and began production in 1980. The mine extracts fifteen million tons of mine material annually from a single open pit. Forty percent of the mined material is saleable product and the remaining sixty percent is stacked on discard dumps. The Daarby fault forms the northern boundary of the open pit and serves to bring the younger Letaba and Clarens Formations into contact with the older Beaufort and Ecca Groups. The mine discards are deposited north of the fault on a different hydrogeological environment from which they are mined. Dewatering of the mine open pit has resulted in a steady decline in water levels in the Ecca Group, south of the Daarby fault. In contrast, water levels north of the Daarby fault in the Letaba and Clarens Formations have risen. The short term hydrochemical impact of the mine discard dumps and slimes dams have resulted in a rise in the calcium, sulphate, chloride, fluoride and nitrate concentrations of the ambient groundwater . The longer term hydrochemical impact from the waste dumps, acid mine drainage, is not evident at present in the groundwater below the waste dumps. However, it is expected to manifest itself during the next ten years. A monitoring system was installed at the mine to allow groundwater levels and quality to be monitored. By measuring groundwater quality and levels the impact of the mine on the regional hydrogeology can be monitored and assessed presently, and during the next forty years of production. Monitoring will also enable the timeous implementation of remedial measures at an early stage and eliminate the need for large late stage "clean up" operations. Future monitoring of both water levels and quality will be crucial in evaluating the mine's impact on the regional groundwater regimes over the next forty years of production. The remedial measures recommended for leachate presently emanating from the waste dumps and slimes dams north of the Daarby fault, are a number of collector wells drilled into the basalts and sandstone north of the Daarby fault. The proposed positions of the wells (boreholes) are as close as possible to the dumps and slimes dams with expansion taken into consideration. The boreholes should be designed to lower the water level in the vicinity of the dumps in order to create a nett groundwater gradient towards the dumps and as a result, halt the spread of leachate away from the dumps. Grootegeluk plans to backfill the open pit with plant discards on completion of the mining of zone 2. The backfilled material will consist of the currently produced plant waste and will be covered with overburden and topsoil. It is expected that the backfilling will have a major impact on groundwater quantity if no remedial measures are implemented. The two remedial measures discussed are chemical treatment of the discard material before backfilling or the continual abstraction of water from the pit resulting in a nett groundwater inflow into the pit. No material from the present waste dumps and slimes dams will be transported into the open pit as backfill material
162

A benefit-cost analysis of the coal development of Kaiser Resources Ltd.

Mohr, Patricia M. January 1969 (has links)
This paper is a benefit-cost analysis of the coal development undertaken by Kaiser Resources Ltd. in the Crowsnest area of British Columbia. The benefit-cost analysis is undertaken from the "point of view" of residents living in the East Kootenay prior to the development. The analysis seeks to examine the production efficiency of the allocation of resources resulting from the project from the point of view of East Kootenay residents. The project will provide primary gross benefits in the form of payroll income to local labour. The social opportunity cost of the use of this local labour must be subtracted from payroll income to obtain the net primary benefit. The social opportunity cost of labour is the value of the marginal product of the labour in alternative employment. A secondary benefit will accrue to local factors in the form of an increase in local income through an expansion of service and retail industries. The expansion will result from the regional multiplier effect of the increase in payroll income in the East Kootenay. The general level of unemployment was high in the East Kootenay prior to the development, and I assume that sufficient local labour and facilities exist to supply the increase in demand for services without requiring importation of labour or capital. Income generated by the regional multiplier will therefore accrue to local factors, located in the East Kootenay prior to the development. Intangible benefits in the form of training in coal mining and an increase in the cultural activities of the community will also occur. The costs attributable to the project include the negative externality effect on wildlife and the deterioration of the quality of the environment in the East Kootenay. A decline of wildlife will decrease the value added by local labour in supplying services to non-resident and residents hunters. The consumers’ surplus obtained by residents from hunting will decline, since greater expenditures will be incurred elsewhere for the same or a lower quality of hunting. The tourist industry will also decline in the East Kootenay. The decrease in local value added due to a decline in the quality of hunting and tourism can be estimated. However, the cost to residents of the East Kootenay from deterioration of the quality of the environment cannot be estimated and the effect is denoted as an unmeasurable intangible cost. The cumulative present value of net measurable benefits at 9% is $l4,717.983. A decision concerning the desirability of the project cannot be made on the basis of this calculation alone. The unmeasurable intangible costs and benefits must also be taken into account. The community, using the relative valuations placed on increased regional income versus the quality of the environment as expressed in a political consensus, must decide how large the unmeasurable intangible costs and benefits are. The project is desirable when only measurable benefits and costs are considered. However, if the cumulative present value of net unmeasurable intangibles is negative and exceeds in magnitude the cumulative present value of net measurable benefits, the Kaiser project should be terminated. / Arts, Faculty of / Vancouver School of Economics / Graduate
163

Best cost country sourcing : optimising the value of conveyor belts for coal mining companies

Viljoen, Alida Maria 20 October 2014 (has links)
M.Com. (Business Management) / Background Best cost country sourcing is a relatively new concept and not many organisations are utilising this specific process nor are they optimising this as their sourcing strategy. Best cost country sourcing is one of the most profound sourcing processes available, and it has the ability to increase an organisation’s efficiency and effectiveness if implemented correctly. Purpose The purpose of this study is to determine if best cost country sourcing should be used as an alternative to local sourcing. It includes aspects of the best cost country sourcing process as well as its risks and advantages. Research method The dissertation analyses the process of best cost country sourcing and the effect it has on an organisation’s sourcing strategy. To achieve this understanding it is necessary to do a qualitative investigation, which is the reason a qualitative research was used as the research methodology in this dissertation. Conclusion Pursuing the process of best cost country sourcing requires a lot of dedication and implementation time. It is a complicated process and no two situations will be alike. Each organisation would need to determine the advantages, risks and challenges which they will encounter with best cost country sourcing. Organisations would also need to determine the best cost countries, as well as the criteria they would need to use in selecting potential suppliers.
164

A framework methodology for the cumulative impact assessment of wetlands

Stoop, Aiden 23 June 2008 (has links)
Mrs. D.C. Schoeman
165

Assessing different coal combustion residue backfill scenarios in opencast coal mines, Mpumalanga, South Africa

Vicente, Annalisa Sarga January 2020 (has links)
>Magister Scientiae - MSc / Coal-fired power stations produce large volumes of coal combustion residues (CCRs), which are disposed of in hold ponds or landfill sites. These ash storage facilities are limited in space and are approaching the end of their capacities, thus additional land is required for extensions. If new land is not sourced, power plants will be forced to cease operations, resulting in increased expenditure costs and environmental liability. A proposed disposal solution is to backfill opencast coal mines with CCR monoliths. However, there is limited knowledge on the hydraulic behaviour of CCRs in an opencast coal mine environment. This leads to an inability to assess this applications feasibility and determine whether this activity will have a positive, negligible or negative effect on groundwater quality. This study aims to address this gap in knowledge by assessing the flow and transport properties of CCRs under numerous theoretical backfilling conditions.
166

A study of the correlation between dragline diggability and blasting technology at Syberfontein colliery.

Frimpong, Mensah. January 1994 (has links)
A project report submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master ofil science in Engineering. / Given the high capital intensity of the dragline operation, the mine can not afford to" tolerate fragmentation problems with its concomitant low dragline productivities. At Syferfontein colliery very large boulders and completely unfraqmented sections resulting in Low digging efficiency of the dragline were encountered in the interburden blast, This project, investigates the causes of the blasting related problems with an intent of improving dragline productivity at the minimum possible cost. This is achieved through blast monitoring, evaluation of the existing practice (blast design) using empirical relations, fragmentation assessment using a model, analysis of operators performance and dragline availabilities. Dragline productivity is evaluated in the light of the various productivity indices , viz, fill factor, fill time and BCM/H. The results indicated explosive incompatibility with the blasting environment and. questionable practices regarding blast design and Delay performance. Engineering field controls such as reduction in drill pattern, reduction of VODof explosive and improvement in draqline utilisation are found necessary. Contributing 61% to the total cost I concentrating on reducing draqline cost must receive preference over drilling and blasting cost as it would produce the most tangible advantage in any cost reduction effort. Regression equations relating cbst and productivity are established. / Andrew Chakane 2018
167

Assessing how an adaptive management approach was incorporated in the mitigation strategies for acid mine drainage discharge in the Witwatersrand basin

Rantsieng, Masekantsi Rahab January 2018 (has links)
School of Mining Engineering, Centre for Sustainability in Mining and Industry, University of the Witwatersran, 2018 / The predicaments faced by humanity today differ from the past due to the increasing scale of human influence, complexities and uncertainties (Allen et al., 2010), which limit management options. Adaptive management is based on the philosophy that knowledge is incomplete i.e. there will always be uncertainty and unpredictability in the behaviour and dynamics of complex social-ecological systems. Given the complexity of the South African mining industry, this research aimed to explore the link between management and science by assessing the extent to which an adaptive management approach had been incorporated into short-term and long-term mitigation strategies for the discharge of acid mine water in the Witwatersrand Basin. The methodology included a review of the adopted mitigation strategy document, a literature review of adaptive management literature and an in-depth analysis of a case study using nine interviews, conducted with key informants and contributors from the government, an educational institution, industry (mines currently dealing with the issue), and civil society. An inductive and descriptive approach was followed to gather and analyse data to formulate answers to the research questions. The findings of the study indicated that the efforts that went into designing the short-term solutions were limited due to the lack of communicating amongst stakeholders and the failure to incorporate a value-based approach. Results also showed that complexities and uncertainties were not addressed to allow for adaptation to constant change. It was found that the short-term interventions had no managerial flexibility which limited learning. Insufficient monitoring and a lack of transparency regarding the dissemination of monitoring results were highlighted. Moreover, experimental efforts were limited due to lack of capacity and funding. In conclusion, although the long-term strategy incorporated some aspects of adaptive management, the short-term mitigation measures were reactive rather than proactive. It is recommended that on-going training and good communication are maintained amongst stakeholders. Recommendations for economic constraints include the sharing of costs through partnerships, evaluating trade-offs between costs and effectiveness and investigating cheaper measuring methods for monitoring. Risk-averse initiatives such as conducting risk assessments during pilot studies and accommodating for different project scales can be employed to mitigate against resources that are sensitive to change. / XL2019
168

A new blueprint for new digital technology adoption in the mining industry using a systems thinking approach

Fan, Xiang January 2019 (has links)
A dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Masters of Science in Engineering 2019 / Successful adoption of new technologies is critical for the improvement of efficiency and the enhancement of health and safety in South African mining industry operations. However, the process of new digital technology adoption in the South African mining industry has been slow and difficult. This research is aimed at addressing some of the problems associated with the process. As part of this research, a new blueprint has been developed to guide the commissioning entity through the entire process of new digital technology adoption and installation. The new blueprint will provide capability to monitor the quality of the work during adoption, as well as assessment of the outcome of the adoption by measuring the level of compliance for every activity performed by the commissioning entity during the adoption. The reliability of the new blueprint was verified by assessing the performance of the Wits Mining Institute (WMI) in its installation project of the Schauenburg system. The outcome of the new blueprint verification reveals poor planning and inadequate preparation during the installation of this project. The outcome also indicates that application of the new blueprint will reduce the problems associated with the adoption and speed up new digital technology adoption and its installation for better functionality. / NG (2020)
169

Interaction effects due to subsidence in multiple seam mining

Webster, Stephen Leroy January 1983 (has links)
M. S.
170

Influence of complex organic amendments on the oxidation of Pyritic mine spoil /

Pichtel, John Robert January 1987 (has links)
No description available.

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