Magister Scientiae - MSc / The waste products acid mine drainage formed during coal mining and fly ash from coal burning power generation, pose substantial environmental and economic problems for South Africa. Eskom has developed a remediation system employing alkaline fly ash to neutralize and precipitate heavy metals from toxic acidic acid mine drainage streams. The aim of this study was to assess the microbial diversity in and microbial impact on this remediation system. / South Africa

Coal mining in nineteenth century British Columbia was confined almost exclusively to the tidewater coal measures of Vancouver Island where it was expanded rapidly from 1871 to 1891. This dissertation's purposes are to describe the coal industry's rise, account for its fast growth in the seventies and eighties, and assess the coal trade's general impact upon the region's economy. The approach is thematic, focusing in turn upon coal lands, capital, management, labour, technology, markets, production, and productivity. Standard research, organization, and interpretation methods for economic history are followed, including thorough descriptive use of statistical data. Comparisons are intensive and far-reaching, resulting in a close-knit framework upon which important conclusions are based. No effort has been made, however, to offer extensive biographical information on the coal trade's leading personalities. These studies confirm the coal industry's rapid expansion, and determine that all factors of production can explain that phenomenon with a high degree of certainty, though market demand and management technique do so more readily than other agents. It is shown that management methods and styles evolved quickly, the most effective being the owner-manager type as practiced by Robert Dunsmuir, the industry's most successful proprietor. Risk capital was drawn from various sources, including mainly British direct investments, local savings, partnerships (often involving foreign investors), and ploughed-back profits. Entrepreneurs and promoters were active in attempting to develop coal properties from 1864 on, though only those highly experienced in mining and management succeeded. Chronic worker shortages, coupled with the physical problems associated with coal mining in mountainous terrain, forced coal operators to opt early for labour saving technology imported almost exclusively from Britain. The introduction of large numbers of Oriental colliers by Dunsmuir after 1870, (who were willing to work at half the wages whites would), slowed the technological advance of the industry, but not annual rates of production increases. Considerable friction between white workers and management resulted from the latter's initiatives with Oriental labour, while the owners' policy of severely restricting wage-rates caused further serious labour problems, including a high number of work stoppages. Mine safety, job security, and general working conditions also were contentious issues. B.C.'s early collieries relied heavily upon the California market which often was unsteady, but which accounted for approximately seventy-five percent of all sales during the years 1849-91. Domestic users were mainly shipping companies, light industry, and households. Much of the local market was handled at the pithead. The major coal companies streamlined their channels of distribution by opening their own sales offices in Victoria and San Francisco, and. in the case of Dunsmuir, by also building a collier fleet and a railway of his own. The coal industry had a major influence upon southern Vancouver Island's economy, but not a large impact upon the remainder of the province. No determined "attempts were made by coal proprietors or other capitalists to create secondary industries linked to coal production, though colliery owners did invest in land, transport, and retail-wholesale ventures designed either to service their mining activities or to diversify their personal holdings. Such moves occurred later-on, however, as the main thrust of their initial efforts was to establish and maintain the coal trade with California. / Arts, Faculty of / History, Department of / Graduate

A thesis submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in fulfilrMnt of the requirements for the degreel of Doctor of Philosophy. / This thesis has investigated ways of exerting control over coal breaking during blasting. Its ultimate objective has been to optimise the use of explosive energy in blasting so as to ensure reduced production of coal fines in the comminution process. The investigations reported were conducted on laboratory models at a scale of a controllable energy to enable the development of a theoretical background for the thesis, However, the bulk of the work was undertaken insitu in surface and underground coal operations. The research was conducted in three phases. The first phase dealt with the approach to modelling the primary crushing mechanism which generates the coal fines during the blasting operation. A laboratory apparatus to simulate blast-generated dynamic loading was devised. Dynamic coal crushing test conducted on a set of over 150 samples of coal showed an exponential relationship; between the comminution energy and the subsequent coal damage. A comminution index (Com ) characterising the ability of coal to generate fines was derived. The second phase of the research concerned the field investigations. This had the following double aim: validating the hypothesis of the influence of the dynamic loading of the shock waves and that of the inherent discontinuities imbedded in coal on fines generation; and quantifying the problem of fines in the blasting techniques currently used in the local mining industry. Three sites were used, namely Kleinkopje of AMCOAL, Greenside of Goldfields and ATC, Tavistock of JCI. The investigations undertaken at Kleinkopje (surface mining operation) involved the determination of discontinuities by logging inherent fractures appearing on 75 diamond drilled cores of coal and the monitoring of 76 blasts conducted on the sites sampled for discontinuities. These investigations indicated a good correlation between the fines observed in blasted piles and the fracture frequency of the pre" existing fractures per metre of coal. The work undertaken in underground collieries (Greenside and Tavistock) demonstrated the enormity of the fines' problem in the local mining operations. Approximately a third of the coal broken underground was observed, in 30 blasts sampled and analysed, to fall into the category of fragments of under 6 mm termed 'coal fines', Which generate low income. The third phase of the research dealt with the optimisation of coal breaking during blasting. A series of 100 trial blasts was undertaken with the aim of searching for a blasting technique that enables the generation of fewer coal fines. A number of options were investigated. Trial blasts carried out were evaluated and their results are discussed in this thesis. The results of the fieldwork undertaken confirmed that fines generation is site speolflc, However, the decoupling technique used with high VOD explosive products may be successfully employed to reduced coal fines generation in strong coals (few inherent fractures). / Andrew Chakane 2018

A research report submitted in partial fulfilment of the requirements for the degree of Master of Science in Engineering, to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, 2019 / A dynamic simulation study is a critical deliverable of a mine project feasibility study. Mining houses rely on simulation to confirm that complex, integrated systems can achieve design capacity before investment decisions are made. Dynamic simulations are powerful tools, but only if they are developed using the right methodology, and with information that has been verified. The importance of work in the field of mine dynamic simulation validation was made clear during the early stages of this research report when it was identified that there is limited information available on the subject. Work conducted in the realm of validation can make an invaluable contribution to the success of future projects undertaken around the world. The last few years have been difficult for employees of some mining companies because of looming job cuts due to high production costs, high overheads, and decreasing product demand. For many mining companies, it was a case of survival which gave rise to the development of new strategies and innovative thinking. Coal Mine A Life of Mine (LOM) extension project is a prime example of innovative thinking. In this case, the project was approved for implementation when export coal prices were on the low end of the price cycle. The dynamic simulation of the full materials handling value chain conducted during the project was of utmost importance, and provided assurance to the project review team that annual production targets can be achieved. The simulation development methodology was based on a unique approach that reduced time spent on the simulation through the integration of different, independent models that represented sub-systems in the materials handling value chain. There was, therefore, a strong need to validate the simulation, which could lead to the adoption of this approach on future projects. In this research report, the LOM extension project scope and the mining activities conducted by Coal Mine A are explained, and a brief, but interesting history of Modelling and Simulation (M&S) is provided. The subject of M&S is vast and has evolved into its own separate discipline. M&S is an invaluable tool, and the importance of verification, validation and credibility is elaborated on. The development of the simulation and the inputs and outputs of the simulation are discussed before the validation effort. The work conducted on the validation aimed to confirm the accuracy of the simulation unequivocally. Although the production target was not achieved as predicted by the dynamic simulation during the period of validation, there was an indication that the materials handling value chain could perform as predicted as each of the individual sub-systems had achieved the design capacity. Problem areas were identified which could be attributed to the poor performance, and if these areas are addressed, the system could perform as predicted by the simulation. This confirms that dynamic simulation can add value to predictions about mining system performance such that informed decisions can be made. / TL (2020)

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A reliable estimate of minable coal reserves is essential for long-term planning and for conservation of energy resources. In the majority of the world's coalfields, seams are found on multiple horizons, and coal recovery may be significantly reduced depending upon the magnitude of seam interaction. In order to evaluate the effects of interaction in terms of coal losses, a hazard technique has been developed. The first stage in this technique was to develop an efficient and accurate system to grid spatial geologic and structural information developed from randomly placed boreholes. The second stage was to utilize these gridded values to determine total available coal tonnage and chemical compositions of the seam. Depending on whether over or under mining effects are to be assessed, spatial geologic and structural conditions between the seams, are evaluated to determine if interaction is possible. Where interaction will occur, recoverable reserves are reduced accordingly. To demonstrate application of the hazard approach, potential interaction in a lower seam has been evaluated. To facilitate implementation of this reserve evaluation method under multi-seam conditions, a user-friendly computer design program, HAZARD, has been developed to calculate the recoverable coal reserves in an affected seam. / Master of Science

A thesis submitted to the Faculty of Engineering, University of the Witwatersrand, in fulfilment of the requirements for the degree of Doctor of Philosophy in Electrical Engineering. / Lightning causes electrical shocks to people, the premature ignition of explosives, and the ignition of methane underground in coal mines. This study examines this problem using a theoretical study and the results of an extensive measurement programme that was conducted in several coal mines. The work that has been done, particularly in South Africa, is also reviewed. Two mechanisms are responsible for the penetration of lightning surge currents into the underground workings. A direct strike to the service structures leading into a shaft is one of the two mechanisms, and the second is that resulting from lightning strikes to the strata above the underground workings. The frequency and amplitude with which such surges can be expected is quantified using the theoretical study. This model correlates well with the observed frequencies of the empirical studies. The sensitivity of methane to lightning-type sparks is investigated. Currents as low as 10 rnA have been proved to be capable of igniting methane. The sensitivity of conventional detonators is also investigated. The thesis proposes a generalised test which can be applied to both the low-impedance protection method and a high-impedance protection method. The test methodologies have been generalised to make provision for any new innovative detonators that may be used by the industry. A risk evaluation of mines is developed which allows a mine to be categorised according to the likelihood of lightning causing an accident in a mine. The South African Recommended Practice for avoiding such accidents is also reviewed. / Andrew Chakane 2018

The thesis starts by defining technological change, productivity and safety. Different definitions are discussed and their merits compared. A brief history of coal mining, together with a description of the state of the mining industry at present is given. Technological innovations recently adopted by the industry are discussed. The concept of productivity in relation to the coal industry of the U.K., and the deficiencies of the present measurement technique, are fully explained. Safety in the coal mining industry of the U.K. is investigated. A brief history is given, together with a full discussion of the consequences and costs of accidents. The concept of technical productivity is introduced and its relation to total productivity explained. The total productivity concept is then applied to longwall coal faces. A multi-variable non-linear model is devised which represents mean total productivity of all longwall faces to an accuracy of about J7G. The model is tested and a forecasting method suggested. Total productivity components are analysed and values for the productivity of various inputs during the period 1958-1980 given. Similarly, a model for representing safety, based on costs, is introduced, tested for accuracy and its components analysed. By applying marginal analysis to the total productivity and safety models, the influence of technological change on productivity and safety are quantified. It is concluded that a new method for measuring productivity should be adopted, in which case total productivity would be the most realistic and comprehensive choice. The models introduced can serve as useful tools in planning and forecasting, as well as being used to measure productivity and safety. Since this work has been in progress, work at the NCB has also led to consideration of improved measures of productivity.