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By D. J. C. Taylor, R. A. Kruger

Unbridled mining operations can have a serious negative impact on the surroundings. With the recent increased awareness of the need for environmental conservation and the resulting advances in environmental control, the mine planner has new tools at his disposal for the successful implementation of mining projects while avoiding negative environmental effects. This paper discusses the environmental strategies adopted in the planning and commissioning of a trial underground coal mine. The minimization of negative environmental effects is demonstrated and, where applicable, environmental benefits are examined.

Jan 1, 1986

By J. A. L. Napier

Computer programs which rely on the assumption of linear, elastic rockmass behaviour have been used routinely for many years in the South African mining industry to determine the stresses arising in the vicinity of mining excavations. A description is given of the theoretical background and novel solution techniques used in the recently developed MINSIM-D boundary element program. Features of the program include the ability to analyse multiple interacting reef planes at arbitrary orientation to one another, slippage on fault planes and the effects of backfill placement in mined areas. Incremental mining sequences can be modelled, and digitizer and front-end routines have been written to assist in the capture of mining outlines and general problem specifications. A brief indication is given of design problems for which MINSIM-D is appropriate, as well as some future extensions of the system.

Jan 1, 1987

By K. L. Morton, R. .. J. Connelly, P. C. Bouw

Uncertainties in the forecasting of the volume of groundwater likely to enter underground workings present difficulties for mine management in planning and costing the water-related activities of mining. This paper describes a technique that was developed to assess future inflows into a gold mine in the Orange Free State. The approach employed was based on the interactive operation of two separate computer models: a regional-flow model and an inflow model. As a first stage, a regional finite-element model of groundwater flow was set up and calibrated. Predictive runs were made to establish the influence of mining on the water levels from base-line conditions. This step was necessary since observations of the regional water levels were sparse. The predicted water levels were transferred to the inflow model, and the future flowrates were calculated. Both models were calibrated by trial and error until a satisfactory match was obtained between historical records and the values predicted by modeling. In this way, an improved monitoring system to record regional water levels and pressure heads within a mine was established. By the use of information, the initial model predictions can be refined as mining progresses. The models used are based on a non-linear relationship between the area mined and the inflows. A phased behaviour in the rates of inflow increase was noted. In conclusion, the modeling approach can provide mine management with guidelines for dewatering requirements. The confidence levels depend upon the records that have been collected during the mine's history.

Jan 1, 1988

By D. A. Viljoent

Historical Background The Empire Council of Mining and Metallurgical Institutions was formed during the early 1920s to foster the holding of British Empire Conferences, and today is representative of the following Institutes: Australasian Institute of Mining and Metallurgy Canadian Institute of Mining and Metallurgy Geological Society of South Africa Institute of Petroleum Institution of Metallurgists Institution of Mining and Metallurgy Institution of Mining Engineers Metals Society Mining, Geological and Metallurgical Institute of India South African Institute of Mining and Metallurgy South Wales Institute of Engineers. The first public suggestion for the formation of a Council that would link mining institutions in various parts of the British Empire came from Mr Frank Merricks, who, as President of the Institution of Mining and Metallurgy, was speaking at the annual dinner of the IMM in 1921.

Jan 1, 1981

By M. Gericke

Over the past few decades the commercial application of heap bioleaching technology for the extraction of base metals has become increasingly important, due mainly to the depletion of high-grade ore reserves. Heap bioleaching is widely used for the extraction of copper from secondary copper sulphide ores. The design and engineering aspects of the process have received considerable attention, but issues related to the microbiology of the process have been subjected to less rigorous scrutiny. The major role of micro-organisms in bioleaching processes is to catalyse the regeneration of ferric iron and protons, from ferrous iron and by sulphur oxidation respectively. It is accepted that even the most carefully engineered heaps are heterogeneous in terms of temperature, pH, the presence of anaerobic pockets, irrigation efficiency, and dissolved solutes. Since interactions between solution chemistry, mineralogy, and microbial populations exist in heaps, a better understanding of the correlation between microbial numbers and types with changes in these chemical and physical profiles with time would be beneficial during process design and operation of heaps, and could result in faster start-up times and higher metal recoveries. This paper reviews the role of microbiology in heap bioleaching processes. Aspects such as microbial diversity, identification and monitoring of cultures, inoculation strategies, colonization behaviour, and tolerance to metals and salts are discussed, and the potential contribution of the knowledge to the improvement of the operation and design of heap bioleach processes assessed. Conclusions are drawn with respect to the role of genetic engineering, heap inoculation practises, and remaining areas for future heap bioleaching research and development.

Jan 1, 2012

By A. W. S. Schumann

G. H. HENDERSON INTRODUCTION It is a pleasure to have read Mr Schuman's wide ranging and highly informative paper and also to congratulate him. Before proceeding to give views on the use and preservation of coal in South Africa, it is perhaps apposite to look at the South African scene on the world canvas. Mr Schuman's figures in his Table I are highly revealing. The Table shows expected consumption, export and import demand in the year 1980 by the continents of the world. The Republic of South Africa is shown as one of only four exporting countries at that date, although in the interim, Australia has become an exporter and will continue to grow as an exporter of coal. Huge fields have been proved in recent years. There is reason to think that for some years, coal and its economical uses have been under-estimated. The importation of oil carries a constant question mark and the exciting possibilities expressed in the uses of Dranium a decade ago for power generation, appear to have met with some setback. Present indications are that breederreactors will be delayed until about 1990. The capital cost of such reactors, too, is enormous. By 1980 it has been estimated that 20 per cent of the energy required by the leading ten nations of the world will come from nuclear power, but 80 per cent would then remain for fossil fuels and hydro generation. COAL DEMAND AND USAGE It is of interest to record that coal production in all the countries of Europe has declined markedly in the last 25 years. This is due to competition from oil, gas and nuclear power and also for sociological reasons; but there are signs that efforts will be made to resuscitate, at least in some measure, the mining of coking coals for which there is a strong and growing demand. Possibly all hard coal now mined in Germany has coking properties and that country is self-sufficient in this commodity. Germany might perhaps consider selling coking coal to her neighbours and importing additional coal for power-raising purposes. It has been frequently stated in American publications that the coal reserves of the D.S.A. are sufficient for 1 000 years. What that means, I do not know, but it is at least an indication that America has huge reserves of coal. Domestic and export demand in the U.S.A. in 1968 exceeded production for the first time. In 1969, the United States' output amounted to some 556 million tons, an increase of less than 2 per cent on the previous year. The output achieved fell short of demand, domestic and export, by more than 7 000 000 tons. This has caused and is continuing to cause anxiety in the U.S.A. In many countries young men for a number of reasons, largely environmental and social, are not coming forward in sufficient numbers for mining requirements and the same pattern has revealed itself in the Republic. This is, indeed, alarming because mining men in large numbers will be required to meet the estimated tonnage requirements set out in the following Table: It is difficult to visualise the replacement of these coal requirements either by oil or by nuclear fuels. The coal must be mined and men are required for the purpose. Unless a greater section of the population is allowed to participate in the more responsible aspects of mining, there is a serious likelihood that demand will not be matched by output. In addition to local demand, a lively export trade is possible. Exports are dependent on the future capacity of the South African Railways and Harbours and on Government policy. An export figure of 10000000 tons per year during the decade can be visualised and this figure would raise total estimated sales production to a figure of over 100 000 000 tons in 1980. At this point, it is necessary to examine the desirability or otherwise of exporting coal. How much coal

Jan 11, 1970

By J. Loubser

The concept of caring is in most cases confused with material needs and not psychological needs. By giving employees a job, most managers think that employees should be grateful and return the favour by being loyal, productive and working safely. Other managers hold the view that employees can be lucky to have a job. To show and demonstrate that management are caring for the safety of the workforce requires involvement, dedication and commitment. Obtaining the trust and respect of the workforce should be the main thrust of any organization because within trust and respect lie the secret of optimal safety performance. In the last 70 years, all the fatalities and serious injuries that occurred in the mining industry can be traced back to one thing, non-caring. The same safety non-compliances are still observed, reported and planned against as 70 years ago, and strange as it may sound, the same injuries occur the same way. The question could be asked: Does the mining industry need more risk assessments? More codes of conduct? More engineering. Or does the mining industry need more caring?

Jan 1, 2010

Professor Miklos Salamon, Research Adviser to the Chamber of Mines of South Africa, has won the Rock Mechanics Award for 1983 of the American Institute of Mining, Metallurgical and Petroleum Engineers 'for applications of analysis to many varied practical mine design problems’. Mintek reports Report M119 A versatile computer programme for data capture in multi-element analysis by a sequential X-ray spectrometer. Report M120 South African costs of equipment for the metallurgical industry (1983). Report M125 Commissioning of an automated microphotometer used in spark-source mass spectrometry.

Jan 1, 1984

By A. Muller

The magnesia-carbon refractories used in the ConArc process experience severe wear as a result of the varying slag composition during the blowing phase. This work determines the basicity range in which minimum as well as maximum refractory wear was experienced by the magnesia-carbon refractories during service. In order to determine an optimum slag composition, the crucible test in an induction furnace was used. The magnesia-carbon refractory bricks were cut into cylindrical crucibles to which a synthetic slag in the form of pellets was added. The basicity (B2) of the slag was varied from 0.5 to 3. Tests were done at 1 600°C for one hour. Apart from the crucible test in an induction furnace, visual inspection and SEM analysis were also done to investigate the corrosion mechanism. FACTSage® predictions about the interaction between refractories and slag were also done. These predictions were compared to the actual results attained. It was found that the extent of corrosion by slag attack decreases as the basicity increases. The most severe corrosion of the MgO-C refractories occurred at a basicity of 0.5 whereas the optimum basicity is above 2.0. SEM analysis indicated severe slag attack at the lower basicities with no visible refractory-slag interaction at higher basicities. TheFACTSage® predictions supported most of the actual findings. Keywords Magnesia-carbon, ConArc, blowing phase, slag resistance, induction furnace, crucibles.

Jan 1, 2011

By M. C. van Blerck

This paper examines the South African fiscal system as it applies to the mining industry and, where components are found wanting, discusses possible alternatives. It is concluded that the South African system has long provided a stable environment for mining investment and growth. However, the introduction, of steep surcharges during the past decade or so (since abolished) and ring fencing (since relaxed but not abolished) has started undermining this stability.

Jan 1, 1994

By J. McPherson

In order to add value to South Africa?s gold reserves AuTEK, a joint venture between Mintek and Anglogold-Ashanti, was started in 2000 with the aim of developing new industrial uses for gold. Accordingly gold catalysts are being made in kilogram quantities by Project AuTEK and sold toend users and other interested parties under the trade name AUROliteTM. Although these materials are optimized for use in CO oxidation applications, demonstration of appropriate activity, selectivity and durability in both liquid- and other gas-phase reactions has been shown1. The review below highlights the recent use of these materials, and other gold catalysts, in reactions of commercial interest.

Jan 1, 2009

The following letter has been received from Professor P. A. Young, Head of the Department of Mining and Mineral Engineering at The University of Leeds, England. Extractive and process metallurgy The first annual TMS-AIME Extractive and Process Metallurgy Fall Meeting:1983 International Sulfide Smelting Symposium, will be held from 6th to 9th November, 1983, in San Francisco.

Jan 1, 1982

By G. Y. Nisbet

The contribution made to the economy of South Africa by the-minerals industry is discussed according to four of its aspects. Firstly, the industry supports both students and lecturers in technical and academic institutions. This support covers virtually the whole range of courses available at the universities and technikons, although most is obviously devoted to the engineering and science faculties. Secondly, the industry makes a direct financial contribution to the State in that it contributes about40 per cent of the State's receipts from direct tax paid on incomes and 30 per cent of the contributions to the total State revenue. It provides employment for 28 per cent of the total active labour force, and contributes 24 per cent directly to the gross domestic product. Thirdly, the industry is responsible for over 65 per cent of the country's foreign earnings in spite of the significant rise in exports from the manufacturing sector. South African minerals are of crucial importance to the word, since the country has the world's largest reserves of seven minerals and features very prominently in many others. Finally, the industry makes an indirect contribution, referred to as the multiplier effect. This is the ripple effect on the economy made by a large injection of momey by which that money acquires an added effective value. A study made of the total production of the mining industry in 1978, for instance, showed this multiplier to havea value of 1,5. Thus, if this effect is included, the industry's contribution to the gross domestic product is 44,S per cent. Similarly, the industry is responsible for the creation of jobs both within itself and in other industries, which could amount to 100000 for the period 1981 to 1935.

Jan 1, 1981

By J. P. G. Pretorius

The size effect in tests of the compressive strength of coal specimens differs from predictions based on the Weakest Link theory. Predictions of the size effect in tensile tests on lengths of cotton yarn and glass fibre, the behaviour of which is analogous to the weak link process, also differ from observations. This discrepancy is shown to be caused by the correlation between the strengths of the unit lengths in a composite specimen. The Weakest Link theory is reformulated as the Weakness Correlation theory to account for such correlation. It is shown that weakness correlation is found in rock and it is concluded that at least part of the discrepancy between the predicted and observed size effect in rock strength tests could be attributed to this correlation.

By B. P. Watson

In South Africa, the Bushveld platinum group metal deposits are unique in that they are the largest platinum group metal deposits in the world. These deposits occur as two distinct stratiform tabular orebodies and strike for many hundreds of kilometres. Mining is extensive, with depths ranging from close-to-surface to 2 000 m. The mining method is a variation of planar open stoping. Pillars are widely used to support the open stopes. Crush pillars are commonly used in this role, where the residual pillar strength provides the required support resistance to stabilize the stoping excavations. This paper describes the direct measurement of stress within these crush pillars, and describes the stress?strain behaviour of these pillars. These findings indicate that the measured pillar failure stress is too high. The implications of these findings are that roof damage and pillar bursting could occur, and some examples of this type of damage are shown. The paper concludes that this problem could be mitigated if the three dimensional pillar geometry were modified and the pillars were cut smaller.

Jan 1, 2007

By J. Gholamnejad

Determination of the optimum cut-off grades is one of the most important aspects of mine production planning. A cut-off is a grade below which we choose not to process material. This material is treated as waste and dumped. Dumping waste is accompanied by the rehabilitation cost which will affect the overall cost of final production and also the optimum cut-off grade. Rehabilitation cost is the cost per ton of rehabilitating material of a particular type of rock after it has been dumped as waste. One of the most popular algorithms for determination of the optimum cut-off grade is Lane?s method. Lane formulated the cut-off grade optimization, but he did not consider rehabilitation cost during the optimization process. This cost item should be evaluated first, and then considered during the cut-off grade optimization process. In this paper the rehabilitation cost is inserted directly into the cut-off grade optimization process using Lane?s theory. The cut-off grades obtained using the suggested method will be more realistic than ones using the original form of Lane?s formulations.

Jan 1, 2009

By N. D. L. Burger, S. Thorley

In engineering design of operators? compartments, in underground mining equipment, ergonomics principles are often neglected or not given the full recognition they deserve. This paper defines ergonomics, applies it to machinery in an underground mining environment, and describes the ergonomics analysis undertaken during the design phase of an EJC extra low-profile mining loader. Encompassing the design of the operator?s compartment of this new loader, this paper illustrates the importance of ergonomic principles within the collective design process ensuring that it is fully integrated into the design approach. An ultimate aim of this study is to ensure that all future designs follow this route to guarantee not only the outcome of a highly efficient, cost effective and productive machine but that it is also takes the human factor into account, not only in maintenance but also in operation. Maximizing comfort will have the ultimate outcome of actually increasing productivity beyond expectations.

Jan 1, 2004

A set of six design principles for rock engineering was developed by Bieniawski: design objectives; minimum uncertainty; simplicity of design components; state-of-the-art practice; optimization; and constructability. These principles translate into a ten-step design process. Although this methodology was developed for rock engineering, it is applicable to any design process, feasibility study, etc. Diligent use of such a process will ensure that a defensible design or evaluation has been carried out. Recently a ?strategic conversation? process has been identified by Ilbury and Sunter that includes the following ten steps: scope; players; rules of the game; key uncertainties; scenarios; SWOT analysis; options; decisions; measurable outcomes; and meaning of winning. A comparison of these steps with those of the design process shows a remarkable correlation. This is perhaps not surprising since engineering design is a strategic up-front issue, and front end loading in a project is critical to achieve the expected project performance. Based on the close correlation between the strategic conversation and engineering design processes, a circular design process, rather than a linear process, is proposed. The ?circle of design? better reflects the importance of review and monitoring in the two phases of successful design and implementation?defining the design, and executing the design.

Jan 1, 2009

By P. He

Abstract This paper introduces the test results of dark-gray calcium-shale, discusses the infection of strength characteristic and deformation characteristic due to the angle between structural planes. Keywords calcium-shale, failure form, strength, deformation characteristic, structural planes. Zusammenfassung: basier auf der Anwendung von Problematik des Felsenbauprojektes und Beschaffenheit Felsen unter Beaugnshme auf den Zustand des Druckes von einzeler Welle legt dieser Text dar, wie der Winkel der Schichtstrukturflaeche des schwarzgrau kalziumhaltigen Schieferblocks auf die Zerstoerungs-, Intensitaets- und Deformationseigenschaften einwirkt. Schluesselwoerter: schwarzgrau kalziumhaltigen Schiefer, Zerstoerungseigenschften, Intensitaetseigenschften, Deformationseigenschaften, Flaeche dar Schichtstruktur. Résumé – En fonction de la configuration du massif rocheux sous l’état de la contrainte de pression axiale simple et de la pratique de l’ingénierie de roches, le présent article fait la déscription concernant l’influence de l’inclinaison ? de la couche de structure stratifiée du bloc de schiste calcaire gris noir sur ses caractéristiques de destruction, sa spécificité de résistance ainsi que sa nature de déformation. Mot clés – Schiste calcaire gris noir, Caractéristiques de destruction, Spécificité de résistance, Nature de déformation, Couche de structure stratifiée

Jan 1, 2003

By C. G. Goncalves

The Gautrain rapid rail link project is currently Africa?s largest infrastructure project connecting South Africa?s major airport (OR Tambo), Johannesburg and Pretoria. Phase one is planned for completion in time for the 2010 FIFA Soccer World Cup and involves 80 km of track and 15 km of underground tunnels. The key shaft sinking blasting issues revolve around maximising advance and improving blasting cycles to meet the tight deadlines as well as environmental control which, in some cases takes place only 15m from the city infrastructure. To achieve success, DetNet South Africa supplied a range of electronic detonator systems to cater for the different blasting applications involved (tunnels, portals, shafts and viaduct foundations). One such product, QuickShot, was used for the first time in a major civil engineering project and has been used in most of the shaft sinking blasts to date. The QuickShot system combines pre-programmed electronic detonators with special on-bench components that enable the user to quickly and easily design the firing sequence solely by using the order of connections. This precludes the user from having to deal in absolute delay times. The connecting system enables benches to be hooked-up speedily by multiple users who have differing levels of experience. This paper provides details of how, after 33 months, the system has been embraced by the project by aiding in maximised advances, improved cycle times and meeting the required environmental constraints.

Jan 1, 2009