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By J. H. Lazarus

The evolution of backfill-distribution systems for deep gold mines is examined. The status of current technology for the design of backfill-distribution systems is considered with reference to pipeline pressure gradients, pipeline wear rates, and slurry flow regimes. The effect of an increase in the relative density of the slurry on the performance of backfill-distribution systems is illustrated. Future trends regarding the design of backfill-distribution systems are discussed.

Jan 1, 1993

A back-propagation model, which is typical of the models used in the science of artificial neural networks, was applied to the prediction of gossans from the southeast area of Habei Province in China. A success rate of 100 per cent was achieved. The results show that the neural-network approach is good, and that it can be used effectively in the prediction of multi metallic deposits.

Jan 1, 1995

The South African Institute for Mining and Metallurgy celebrated its 95th anniversary with a banquet at The Carlton on Friday, 2nd June, 1989. This event was attended by 600 people, including the Presidents of AS&TS, constituent societies, and other kindred bodies, together with members and their guests. The guest speaker was Mr Muray Hofmeyr, Chairman of the Johannesburg Consolidated Investment Company Limited, who gave an interesting and thought-provoking talk entitled 'Will we still be the best in the year 2001'

Jan 1, 1989

By E. H. van Niekerk

The production of high-strength Iow-alloy (HSLA) steels containing either niobium or vanadium as the principal micro-alloying element is discussed, including recent developments in steelmaking practice that have had a great effect on the development of HSLA steels; strengthening mechanisms, as well as the principles of thermomechanical treatment during controlled rolling on a hot-strip mill; and the results of production heats with various amounts of micro-alloying elements.

Jan 1, 1984

By R. W. O. Kersten

The main objective of The South African Institute of Mining and Metalurgy is to identify the needs of the mineral and metals sector of the South African economy, and to initiate the means by which the requirements for technology and scientific knowledge can be satisfied. To achieve this, the Institute organizes schools to promote technology transfer and to satisfy the needs of its members for continuing education by the exchange of technical information, the communication of ideas, and the identification of technological problem areas.

Jan 1, 1986

By P. King

In considering the available reserves of coal, the author points to the importance of improved recovery, and defines three extraction ratios: the geological extraction ratio (or exploitation factor), the economic extraction ratio (or mining factor), and the geometrical extraction ratio (or volumetric extraction factor). He discusses the factors affecting each of these ratios, and concludes that, although geological factors cannot be considered in isolation from technical and economic factors, the geological extraction factor is the most significant criterion of whether the best use is being made of coal resources.

Jan 1, 1980

To B. K. Martus I discussed several points raised by Mr Martus in my reply to Professor Krige*. Mr Martus discusses several possible interpretations of optimum South African sales, but in my paper these sales refer to the sales level that maximized the working profit of the whole South African gold-mining industry over the past eleven years. Mr Martus also seems to be under the impression that the paper deals with the future. While there may be references to the future, and some implications for the future may be obvious, the paper deals essentially with the past eleven years.

Jan 1, 1984

By F. P. A. Robinson, J. W. Fourie

Austenitic stainless steels are welded using low-heat inputs. However, owing to differences in the physical metallurgy of austenitic stainless steels and duplex stainless steels, low-heat inputs should be avoided for duplex stainless steels. This paper highlights the differences in solidification mode and transformation characteristics of these two types of alloys. Recent work on the effect of heat input on the properties of weldments of duplex stainless steels is reviewed.

Jan 1, 1990

By J. A. Cox, R. P. H. Willis, J. R. Dixon, A. D. Pooley

The paper describes the issues that should be considered when introducing mechanization to a mining operation. In South Africa, traditional methods of mining are well entrenched after more than a century of mining. To successfully change from these methods requires an integrated holistic approach that considers all aspects of a mining operation including setting of objectives, selection of personnel, recruitment, training and remuneration policies, organizational design, mine design, equipment selection, maintenance philosophy, standards and procedures, and monitoring and control. The paper makes reference to experience gained during a variety of on-mine case studies in drawing generic conclusions and making recommendations.

Jan 1, 2004

By H. A. D. Kirsten

The paper reports on loading tests conducted on shotcrete reinforced with mesh and various types of steel fibre, and compares the results with the energy absorbing capabilities of 16 mm rebar shepherd's crooks. It is concluded that mesh-reit1forced shotcrete has sufficient energy-absorbing capabilities to contain rockbursts of significant magnitude, having greater energy absorbing capabilities, even at a thickness of 50 mm, than 16 mm rebar shepherd's crooks. Fibre-reinforced shotcrete has energy absorbing capabilities of the same order as, or better than, those of 16 mm rebar shepherd's crooks, but its performance is erratic.

Jan 1, 1995

By F. H. Deist, R. P. Plewman

The history of development of analytical techniques for the determination of elastic behaviour around tabular excavations, is examined briefly. The design of a completely digital system, which appears to afford considerable improvements in speed, accuracy and versatility compared with existing analogue methods, is described in detail. The practical application of this system is illustrated by means of an actual underground problem. The results are presented, not in the form of specific solutions to the mine's problems, but as indications of the versatility and scope of the new method.

By M. N. James

The Fracture Research Group has been operating at the University of the Witwatersrand for some ten years and, in that period, has achieved a significant profile, both nationally and internationally, through its research publications, industrially-based technical reports, continuing short courses in engineering education, and co1Jferences. This paper outlines the activities of the Group over the past few years, emphasizing the research thrusts and the results that have been obtained, as well as highlighting areas of current and future research interest The capabilities of the Group in terms of equipment and expertise are also discussed briefly.

Jan 1, 1995

By C. T. Connor, O&apos

The fifth University of Cape Town (UC1)/University of Stelenbosch (US) Minerals Processing Symposium was held at the Faculty of Engineering, University of Stelenbosch on Friday, 8th August, 1986. This series was initiated in 1982, the symposia being held alternately in Cape Town and Stelenbosch. The South African Institute of Mining and Metallurgy has kindly agreed to sponsor this event for the next three years. Cokemaking On the initiative of the European Cokemaking Commitee, the First International Cokemaking Congress will be held in Essen (F.R. Germany) from 13th to 19th September, 1987. It is being organized by the Steinkohlenbergbauverein, together with the Verein Deutscher Eisenhitenleute.

Jan 1, 1986

By S. N. Alecsandrov, BulgakovY. F.

Putting out fires in faces is an extremely complex and dangerous operation from the technological point of view which sometimes is accompanied by human victims. The new technology of fire-extinguishing sets giving directly into a mining face has been developed at the DNTU in order to put out such kinds of fires. The technique presupposes an availability of special installation placed on ventilation and conveyor mining drift. In case of fire a special fire-extinguishing powder is delivered with the help of remote control into mining face. Subjects, allowing to determine powder delivering distance in the frame of mining workings are presented in the report. The given technology substantially increases safety of accident work which are carried out in case of fire.

Jan 1, 2003

The rising tide of environmentalism has adversely affected many mineral producers, but it has also provided them with a number of opportunities for mineral applications. These markets are as diverse as water treatment, waste disposal, and flue-gas desulphurization. Whilst legislation is forcing up the industry's environmental standards, the advent of environmental management provides an opportunity for producers to display its 'green' credentials. The picture painted of the extractive industry by environmentalists is undeservedly black, because the more efficient a producer is, the more effectively that producer conserves the very resources he exploits. The 1993 IM Forum examined these issues and how they affect the mineral producer, and this publication comprises the papers presented at that meeting.

Jan 1, 1995

The relationships between backfill-transportation parameters (solids concentration, velocity, and pipe diameter) and the wear rate of backfill-transportation pipelines is well understood. However, the degree of wear experienced by a pipeline depends not only on the transportation parameters, but also on the characteristics of the solids making up the backfill, i.e. the particle-size distribution, hardness, shape, and sharpness of the particles. Therefore, unless data corresponding to the specific wear rate of the solids are available, the determination of the wear rate for pipes transporting an uncharacterized backfill is largely guesswork. This paper describes an evaluation of particle characteristics with special reference to particle sharpness so that pipe wear rates can be correlated with solids of different size distributions and sharpnesses.

Jan 1, 1993

By A. Ball

A fully instrumented laboratory drilling machine is described. It is designed to produce realistic drilling conditions with diamond microbits of 20 mm diameter. A computer-controlled data-logging system records the net power consumption, rotational velocity, bit thrust, torque, and penetration rate. Tests can be conducted under conditions of set thrust and rate of advance. In the tests reported, there is a significant correlation between the rock drilability and the measured rock properties of relative abrasion resistance and uniaxial compressive strength. Wear of a diamond bit is a crucial factor that cannot be determined simply from rock properties. Realistic drilability testing with appropriately scaled microbits is a convenient and economical way of evaluating diamond-bit performance and determining rock drilability.

Jan 1, 1990

By J. A. Wates

Stope backfilling in South African gold mines uses the coarser cyclone fraction of the gold tailings. The disposal of the overflow from the cyclones, which is finer and of higher moisture content than normal gold tailings, presents some problems. This paper describes an investigation undertaken to define the parameters that are required for a quantitative and qualitative assessment of the operation and stability of slimes dams built of such material. However, seeing the investigation was conducted on the slimes from only one mine, it is recommended that, until a wider range of data becomes available, tests should be conducted for each individual mine.

Jan 1, 1988

By G. J. Krige

The extent of ground movements and stress concentrations in the vicinity of the reef in the deep mine-shafts used in the South 4frican gold-mining industry have led to the requirement that special tower structures be developed to span the reef intersection zone in several new shafts. So that structural engineers are able to design these towers, it is necessary to model the dynamic behavior of conveyances traversing them in some way, to provide a means to determine the magnitude of the forces generated. This paper describes the development of two such procedures. The first is a numerical method, utilizing a step by- step integration technique to track the motion of a conveyance through a tower. This technique has been implemented in a computer program, and some results are given.

Jan 1, 1995

By A. K. Haines

The status of the South African research and development programme on continuous ion exchange, which was aimed at the technical and economic assessment of that process for the recovery of uranium, is reviewed. The first phase of this programme, which has now been completed, involved development investigations on various pilot plants and culminated in the successful operation of a large-scale demonstration plant and the incorporation of the system in a number of new South African uranium plants. This account highlights the engineering aspects and the design fo the system, its adaptation to process flowsheets, and plans for future development.

Jan 1, 1978