A project report to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, In fulfillment of the requirements for the degree of Master of Science / A detailed analysis was performed on statistics obtained from twenty two gold mines in different mining districts, to determine the parameters which affect labour productivity and working costs, (Abbreviation abstract) / AC2017

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Scieuce in Geophysics . / Rockbursts continue to be one of the more high profile and problematic worker hazards in the South African gold mining industry. Recent advances in the technology of seismic monitoring systems and seismic data analysis and interpretation methods hold considerable promise towards improving the success rate of rockburst control measures. This study tests different methods for the evaluation of the response of geological structures to mining induced stress changes. A small part of Western Holdings Gold Mine in the Welkom goldfield -- the Postma Area -- offers a challenge because of its geological complexity, accessibility and high incidence of seismicity. The sensitivity of the local network to ground motions in this area of interest and the expected spatial location accuracy is established and deemed adequate for a detailed investigation of seismic activity. The local mining geometry, geology and methods of mining are discussed. The fractured state of the rock mass observed in situ, close to the stope faces, is in agreement with the results of numerical elastic modelling and the high stresses inferred seismically. Almost immediately after the incidence of a large event (ML 3.7) which occurred close to one end of a dyke, an increased rate of seismic activity became apparent at another part of the same dyke, some 250 m to the east. A change in the state of seismic stress, before and after the large event, points to a transfer of stress along this geological discontinuity. A quantitative analysis of recorded seismicity indicates spatial and temporal variations in the state of stress and strain throughout the rock mass surrounding Mining excavations. The elastic stress modelling performed routinely by rock mechanics engineers in the deep gold mines is, by itself, incapable of catering for the rheological nature of the rock mass, but taken together with independent seismic evaluations of a fault orthogonal to a highly stressed dyke it is shown that both methods are mutually complementary and can enhance the assessment of the seismic instability of the structures. A back-analysis is conducted on ten large seismic events (ML> 2.5) to identify precursors. These show that the timely recognition of high gradients in physical seismic parameters pertaining to strain rate and stress in time and space immediately prior to major seismic events is a real and practical possibility, as such constituting an early warning mechanism. The fore-warning of a large event is best served by an analysis of seismicity over the short term (weeks or days) through time-history variations and/or contouring of various seismic parameters, although long-term seismic responses (months or weeks) characterise specific patterns and trends which are useful in the forecast. / AC2018

A thesis submitted to the School of Animal, Plant and Environmental Sciences (APES), University of the Witwatersrand, Johannesburg, South Africa in fulfilment of the academic requirements for the degree of Doctor of Philosophy Johannesburg, February 2013 / Decades after the commencement of modern mining in the 1870s, the South African mining industry addressed the impacts associated with its mine waste deposits. In this, it followed the pattern its international peers had set. This study aims at chronicling, for the first time, the mining industry’s efforts to develop scientifically sound and replicable methods of mine waste rehabilitation. Mindful of the limitations in accessing official and public written sources for such an applied science, the study seeks to take a broader approach: It considers factors beyond pure experimental results (of which only patchy records exist), and considers the socio-economic context or the role of certain personalities, in an effort to understand the evolution of the applied technology between the 1930s until the passage of the Minerals Act in 1991. The bulk of this mine waste rehabilitation work during this period was done by the Chamber of Mines of South Africa and its members, the gold and (later) coal miners. The focus will therefore be on these sectors, although other mining sectors such as platinum will be covered when relevant. Following decades of ad hoc experimentation, concern about impending legal pollution control requirements in the 1950s spurred key gold industry players to get ahead of the curve to head off further regulation. Their individual efforts, primarily aimed at dust suppression, were quickly combined into an industry initiative located within the Chamber of Mines. This initiative became known as the Vegetation Unit. Well resourced and managed by a dynamic leader with horticultural training – William Cook – the Unit conducted large-scale and diverse experiments between 1959 and 1963 to come up with a planting and soil amelioration methodology. The initial results of this work were almost immediately published in an effort to publicise the industry’s efforts, although Cook cautioned that this was not a mature methodology and that continued research was required. The Chamber of Mines, however, was trying to head off pending air quality legislation and in 1964/65, the organisation publicly proclaimed the methodology as mature and ready for widespread application. With this decision, the Unit’s focus shifted to widespread application while its ability to advance the methodology scientifically effectively collapsed in the 1960s and early 1970s. In addition to this shift of focus and resources to application rather than continued refinement, the Unit was constrained by non-technical and non-scientific factors: Key among them was the industry’s implicit belief, and hope, that a walk-away solution had been found. The Unit’s manager Cook stood alone in driving its application and refinement for most of his time in that position. In his day-to-day work, he lacked an industry peer with whom to discuss rehabilitation results and he compounded this isolation through limited interaction with academia until very late in his career. This isolation was amplified by the lack of relevant technical knowledge among the company representatives on the committee tasked with the oversight of the Vegetation Unit: As engineers, all of them lacked not only technical understanding of the botanical and ecological challenge, some even questioned the legitimacy of the Unit’s existence into the 1980s. In addition, the concentration of all rehabilitation efforts in this single entity structurally curtailed the individual mining companies’ interest in the advancement of the methodology, creating a further bottleneck. Indeed, as late as 1973, the key metallurgy handbook covered mine waste rehabilitation only for information purposes, specifically stating that this was the responsibility of the Chamber’s Vegetation Unit alone. To some extent, the presence of a champion within the Chamber – H. Claussen – obscured some of these challenges until the early 1970s. Indeed, the Unit had acquired additional scientific capacity by this stage, which gave it the ability to renew its research and to advance its methodology. That it failed to do so was mainly due to three factors coinciding: the retirement of its internal champion Claussen, a lack of succession planning for Cook, which left the Unit on ‘auto-pilot’ when he retired, and a rising gold price, which turned industry attention away from rehabilitation towards re-treatment of gold dumps. During this period of transition in the mid 1970s, the Chamber’s approach was thus somewhat half-hearted and vulnerable to alternative, potentially cheaper, rehabilitation proposals such as physical surface sealing advanced by Cook’s eventual successor – Fred Cartwright. Though not grounded in any science, Cartwright’s proposal gained ascendance due to his forceful personality as well as the industry’s desire for an alternative to the seemingly open-ended costs associated with the existing rehabilitation methodology. During this time, the Chamber’s structures singularly failed to protect the industry’s long-term interests: The oversight committee for the Vegetation Unit, remained largely staffed by somewhat disinterested engineers, and relied heavily on a single individual to manage the Unit. Not only did the oversight committee passively acquiesce to Cartwright’s virtual destruction of the Unit’s grassing capacity, it also allowed him to stake the Chamber’s reputation with the regulator by championing an unproven technology for about five years. Only Cartwright’s eventual failure to gain regulator approval for his – still un-proven – technique led to a reluctant abandonment by the Chamber in the early 1980s. Cartwright’s departure in 1983 left the Unit (and the industry) without the capacity to address mine waste rehabilitation, at a time when emerging environmental concerns were gaining importance in social and political spheres in South Africa and across the world. The Unit sought, unsuccessfully, to build alliances with nascent rehabilitation practitioners from the University of Potchefstroom. It furthermore failed to build mechanisms for sharing technical rehabilitation knowledge with fellow southern African or international mining chambers, leading to further stagnation of its method. At the same time, up-and-coming South African competitors such as the University of Potchefstroom seized the opportunity to enter the mine waste rehabilitation field as commercial players during the mid 1980s, at a time when the Unit had been reduced to grassing dumps for a single customer, the Department of Minerals and Energy Affairs (DMEA). Using its status as a part of the Chamber of Mines, the Unit gradually regained its position of prominence through the development of industry guidelines for rehabilitation. Yet, it would never again occupy a position of pre-eminence in practical fieldwork, as industry players, academic capacities and commercial players entered the field in the mid-1980s in response to a growing environmental movement worldwide. When the passage of the Minerals Act in 1991 formally enshrined not merely rehabilitation but environmentally responsible mine closure in law, the Unit had been reduced to a prominent but no longer dominant player in this sector. This lack of pre-eminence ultimately caused the Unit to be among the first Chamber entities to be privatised when the Chamber began to restructure. This ended its role as a central driver of applied rehabilitation techniques for the South African mining sector once and for all. As this privatisation coincided with the broader opening up of South Africa’s society and economy after the unbanning of the ANC, there would never again be an entity (commercial or otherwise) that would dominate the rehabilitation sector as the Chamber’s Vegetation Unit had done in its day.

Thesis ((M.Sc.) Engin))--University of the Witwatersrand, Faculty of Engineering & the Built Environment, School of Mining Engineering, 2003. / The ore reserves of the Kloof Sub Vertical Shaft operations are coming to an end and as such, the Eastern Boundary Area mining operations, which will extract the Ventersdorp Contact Reef ("VCR"), must be commissioned to replace the diminishing reserves. Although feasibility studies have been carried out on the eastern portion of the Kloof Gold Mine lease area, none have been undertaken to investigate the potential benefits of including the new mineral rights recently acquired from JCI. This project report is a prefeasibility study into the potential value to Kloof of accessing and extracting the resources of the Eastern Boundary Area. This project report shows, using DCF analysis, that the Eastern Boundary Area has potential to economically generate the additional reserves that will be required to supplement Kloof s diminishing Three Shaft reserves. An NPV and IRR are calculated for the project, the results of which support the commissioning of further investigative work in order to obtain a better understanding of the orebody and to generate results that are more accurate. Despite its popularity, traditional DCF analysis has fundamental shortcomings, as do the commonly associated measures of NPV and IRR. This project report identifies and reviews these shortfalls and comments on methods to overcome these as far as practically possible.

No description available.

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Geophysics . / Rockbursts continue to be one of the more high profile and problematic worker hazards in the South African gold mining industry. Recent advances in the technology of seismic monitoring systems and seismic data analysis and interpretation methods hold considerable promise towards improving the success rate of rockburst control measures. This study tests different methods for the evaluation of the response of geological structures to mining induced stress changes. A small part of Western Holdings Gold Mine in the Welkom goldfield -- the Postma Area -- offers a challenge because of its geological complexity, accessibility and high incidence of seismicity. The sensitivity of the local network to ground motions in this area of interest and the expected spatial location accuracy is established and deemed adequate for a detailed investigation of seismic activity. The local mining geometry, geology and methods of mining are discussed. The fractured state of the rock mass observed in situ, close to the stope faces, is in agreement with the results of numerical elastic modelling and the high stresses inferred seismically. Almost immediately after the incidence of a large event (ML 3.7) which occurred close to one end of a dyke, an increased rate of seismic activity became apparent at another part of the same dyke, some 250 m to the east. A change in the state of seismic stress, before and after the large event, points to a transfer of stress along this geological discontinuity. A quantitative analysis of recorded seismicity indicates spatial and temporal variations in the state of stress and strain throughout the rock mass surrounding Mining excavations. The elastic stress modelling performed routinely by rock mechanics engineers in the deep gold mines is, by itself, incapable of catering for the rheological nature of the rock mass, but taken together with independent seismic evaluations of a fault orthogonal to a highly stressed dyke it is shown that both methods are mutually complementary and can enhance the assessment of the seismic instability of the structures. A back-analysis is conducted on ten large seismic events (ML 2.5) to identify precursors. These show that the timely recognition of high gradients in physical seismic parameters pertaining to strain rate and stress in time and space immediately prior to major seismic events is a real and practical possibility, as such constituting an early warning mechanism. The fore-warning of a large event is best served by an analysis of seismicity over the short term (weeks or days) through time-history variations and/or contouring of various seismic parameters, although long-term seismic responses (months or weeks) characterise specific patterns and trends which are useful in the forecast. / AC 2018

This thesis analyses the establishment of a health and safety system on the Witwatersrand gold mines in the period between the end of the South African War and the eve of World War Two. The period has been chosen, firstly, because the South African War had seriously disrupted production and the industry virtually had to start up again from scratch; secondly, because it was during this period that mine and state officials began to seriously investigate the reasons for the appalling mortality and morbidity rates on these mines; and, thirdly, because during this period some improvements did occur which were significant enough to enable the industry to warrant the lifting, in the latter part of the 1930s, of the ban on tropicals, enforced since 1913 as a result of their extremely high mortality rate. In the first thirty years of the twentieth century about 93 000 African miners died disease-related deaths and in the same period some 15000 African miners were killed in work-related deaths. In attempting to establish why so many African miners died, the thesis attempts to identify the diseases and accidents that caused these deaths and considers what attempts were made to bring mortality and morbidity rates down. Whilst the thesis is neither a history of gold mining in South Africa nor an economic history of South Africa in the period 1901 to 1939, it nevertheless, as detailed in the first chapter, places the health and safety system within the context of the wider political and economic forces that shaped the mining industry in this period. The need for a productive and efficient labour force, vital for the industry'S survival during a number of profitability crises in this period, forced the industry to reassess compound structures, nutrition and eventually the health of its work force. These issues of compounds, work and diet are discussed in chapters two, three and four. Appalling living and working conditions led to a high incidence of pulmonary diseases - TB, silicosis and pneumonia - which were the principal killers on the mines. Attempts to cure or prevent their occurrence are discussed in chapter five. Fear of disruptions to production ensured that the mining industry eventually also devoted considerable resources to accident prevention, a theme which is discussed in chapter six. The thesis concludes that the mining industry for much of this period was able to determine the pace of change; neither state officials nor African miners were able to significantly alter the tempo. In fact the industry was so successful that it was able to convince a number of government commissions in the 1940s that the migrant system had to stay, to ensure the wellbeing of the miner. This meant that despite considerable time, money and effort being spent on establishing a health and safety system on the gold mines, the mining industry was still of the opinion that the health of their workers was best served if they were sent home.

Thesis (MTech (Chemical Engineering))--Cape Technikon, 2000. / The large quantities of wood chips produced at mines from damaged underground timber contain gold that cannot be completely recovered by cyanidation. A fungus that can degrade a portion of the wood matrix will allow the gold that was previously locked up, to come into contact with the cyanide solution during beneficiation, thereby improving recoveries. The fungus Phanerochaete chrysosporium produces enzymes that use the organic compounds found in lignin as substrate. Consequently, the fungus is able to selectively break down lignin, which is one of the major components of wood. Chips sampled from Vaal Reef Mine contained between 2 and 5 mg/kg gold. The main source of gold in the chips was determined to be impregnated gold-bearing ore and discrete gold particles. Direct cyanidation resulted in around 60 per cent recovery prior to biological treatment. Despite relatively high weight losses caused to the chips as a result of treatment with Phanerochaete chrysosporium gold recovery only increased 10 per cent after 4 weeks treatment compared to direct recovery without treatment.

M.Sc. (Geology) / Please refer to full text to view abstract

The "A" -Reef occurs within the Aandenk Formation of the Central Rand Group, Witwatersrand Supergroup, in the Welkom Goldfield. It comprises the Witpan and Uitsig Reefs which are both oligomictic conglomerates, and are exploited for their gold content by Anglo American Corporation. The main Witpan channel complex is orientated in a NW-SE direction and occurs close to No.3 Shaft of Western Holdings Mine where it is currently being mined. The Witpan Reef varies in thickness from 7-220cm, with lateral facies changes controlling the thickness. Within the reef, gold is associated with degradation surfaces, carbonaceous material, increase in pebble sphericity, and channel edges. Two channel edges have yielded the best gold values on No.3 Shaft although the potential for further payable gold lies in the recognition of sieve conditions. The potential also exists for extensions of the "carbon"-bearing Uitsig channel currently being mined on President Steyn Mine. The palaeo-environment proposed for formation of the Witpan Reef is a braidplain that was partly reworked by a brief transgression. Ore evaluation using geostatistics was considered a valid technique as the dataset is sufficiently well structured. Semi-variograms in the channel and across-channel directions differ markedly. It was found that variograms of gold in cmg/t lacked sufficient structure for modelling, however, log semi-variogram modelling followed by simple log-kriging and back-transformation, proved to be the most successful method. Owing to the morphology and distribution of gold within the reef, a geologically based geostatistical valuation method is proposed. The potential for further exploration of "A" -Reef depends on a substantially higher gold price. In this event, exploration of Uitsig Reef to the southwest of the current mining area is recommended as well as a new exploration strategy for Witpan Reef.