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By T. Dimillo, R. G. B. Pickeirng

The South African gold and platinum deposits were formed in very different ways and yet both have many similarities. They are flat dipping tabular ore bodies, extremely narrow and located in hard abrasive country rock. The mining methods employed are also similar. Primary access is via shafts or declines; secondary access is via haulages and cross cuts; and tertiary access is from raises. The proposed solution for rapid access described in this paper is focussed on the haulages, cross cuts and raises. The non-explosive rock breaking method has many other applications, however, it is the integration with the Tunnel Digging Machine that results in the first, cost effective, Continuous Tunnelling Machine for hard rock mining.

Sep 1, 2001

By D. S. Loubser

The technique of backfilling in the gold mining industry is dependent on the dewatering of slurry to form a solid support system. In many cases flocculants are added to the slurry to increase the rate of dewatering. To ensure that a stable support is obtained it is important that the chemistry, application and limitations of these flocculant additives are understood. Flocculant additives have to be added at a point where minimum shear will occur. (Shear occurs when a flocculant is exposed to excess energy resulting in breakdown, of the floc.) To ensure that optimum results are obtained it is important that personnel involved are trained to use the flocculant additives and dosing equipment correctly.

Jan 1, 1988

By G. Paul

The mechanism of nodular crystallisation of graphite in the production of spheroidal cast Iron is not fully understood. The work reported In this paper confirms that in cast iron melts having a high Interfacial tension against the environmental atmosphere, the graphite tends to crystallise in nodules during solidification. The Influence of Interfacial tension between melt and solid graphite is similar.

By J. Kitagawa

The principal objectives of a metallurgical test programme for a 'grass roots' mining project are twofold. The first requirement is to establish the metallurgical viability of the project by demonstrating that acceptable results can be obtained by processing of the ore. The second goal is to obtain essential supporting data to determine whether the project is economically feasible. This involves several functions, which include the establishment of a workable flowsheet, the obtaining of design criteria for the commercial plant, and the collection of the evidence necessary to convince management, and often a third-party expert, that the metallurgy predicted for the ore can be achieved in a full-scale operation. The latter task is facilitated if a coherent overall picture is presented considering the geology of the orebody, the mining plan, and the mineralogy and metallurgy of the ore. The purpose of this paper is to provide guidance in the establishment of a test programme to meet the above objectives.

Jan 1, 1978

This list of corrosion-related terms was compiled to encourage the use of the correct terminology, and to serve as a handy reference for students. It Is based on a similar list compiled by the National Association of Corrosion Engineers (NACE). To promote bilingualism, the Afrikaans terminology is included (in italics at the end of each entry).

Jan 1, 1991

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

By A. A. Oakes, P. M. C. Wilson

This paper describes some aspects of the planning of a new colliery which commenced production in the Middleburg district in 1966. An account is given of some of the problems encountered in the early years of operation and of what was done to solve them. The conclusion is reached that design of plant and machinery should be flexible to permit multiplication of units.

By A. Hinde, M. Moys, L. C. Woollacott

The material-balance smoothing technique is applied directly to the problems associated with the evaluation of the performance of backfill-preparation plants. A computer package specially designed to assist the process engineer in such evaluations has been developed. The usefulness of the technique as compared with other methods for the extraction of meaningful information from backfill-plant data is demonstrated.

Jan 1, 1992

By G. Nino de Guzman, L. C. Woollacott

The isotherms that are usually taken to represent the force 'driving' the adsorption in carbon-in-pulp processes may change from contactor to contactor. This paper reports on an investigation into the extent to which this Isotherm shift is Influenced by the changes in oxygen and cyanide concentration that occur in operating plants. The impact of the isotherm shift on the reliability of simulation results is examined.

Jan 1, 1993

By P. Wiesner, H. –M. Stonner

A brief account is given of the influence of sulphuric acid and chloride ions during the recovery of uranium by solvent extraction, followed by a discussion of the settling behaviour of dispersions and models to represent that behaviour. The paper ends with a description of various methods for the recovery of solvent, which is lost in the solvent-extraction process by entrainment and adsorption on solids and by dissolution.

Jan 1, 1982

By A. O. Filmer

A study of the dissolution of gold from a pyrite concentrate and from various calcines is reported. The percentage extraction of gold was found to decrease with increasing sulphur content in the material leached because of the porosity of the materials, and particularly because of the passivation of the anodic dissolution of gold when the gold was In contact with other conducting minerals. This is explained in terms of the current-potential curves for the oxidation of gold and the reduction of dissolved oxygen.

Jan 1, 1982

By A. Morley

It is difficult to evaluate exploration properties in a manner that is transparent, repeatable and easily re-calculated to cater for different geological interpretations, but the risk-based assessment methodology, the Geological Risk Method, developed and described by Lord et al (2001) attempts to satisfy all these criteria. This paper examines a case study example based on valuations of exploration projects conducted by SRK Consulting using this methodology, and describes some of the advantages and limitations of the method.

Jan 1, 2007

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

By H. E. Cross

The conversion of a uranium plant to the recovery of zinc by H. E. CROSS. B.Sc. (Eng.)(Hons.) Rand (Fellow) The conversion of the Vogelstruisbult Uranium Plant into a plant for the production of electrolytic zinc is described. The reasons for the conversion, the preliminary investigations. and the basic design principles are all outlined, and a brief account is given of operating experience.. during the commissioning of the plant, with equipment that had been put to a use for which it was not originally Intended.

Jan 11, 1973

By G. J. G. Juby

The Chamber of Mines Research Organization has been evaluating three membrane-desalination processes for use within the South African mining industry. These processes are electrodialysis reversal (EDR), tubular reverse osmosis (IRO), and slurry precipitation and recycle reverse osmosis (SPARRO). The evaluation of EDR and TRO is complete, and the operating costs (1988) associated with each process are expected to be about 50 cents per kilolitre for a plant of 50 l/s (4 Ml/d) installed capacity. The SPARRO process is still being evaluated. Pilot plant results, water Qualities, and expected capital costs are presented where appropriate.

Jan 1, 1992

By B. R. Broekman, D. W. Penman

SYNOPSIS This paper traces the developments in flotation practice at Anglovaal's Prieska Copper Mine, with em¬phasis on the depression/deactivation of lead and zinc. A depressant system was devised to accept feed material that was once regarded as untreatable. Of particular interest is the long-term downward trend of concentrator working costs in real terms. This trend follows the classic Experience Curve, which relates production costs to cumulative experience. It is felt that the experience-curve concept has important implications for the mining industry in general.

Jan 1, 1991

By I. R. M. Chaston

A full and detailed description is given of the dense-medium cyclone plants used in Africa for the recovery of diamonds.

By R. H. English, N. C. Joughin

The results of trials with three stope-face cleaning systems are described. Two of these systems were based on armoured chain conveyors, and the third on a reciprocating-flight conveyor. The operational elements of each system are discussed with reference to their effectiveness, and many problems are highlighted. It is concluded that the reciprocating-flight conveyor is superior, and has the potential for being developed into a system yielding a labour productivity of more than 30 m2 per worker per month and a face advance of 15 m per month working one shift a day.

Jan 1, 1979

By A. M. Starfield

SYNOPSIS A description is given of a new computer programme that has been developed for the rapid computation of the changes in temperature and humidity of air passing through mine airways. The programme enables the ventilation engineer to calculate air temperature increases along airways with an ease that is comparable with that of looking up a set of graphs or tables in an engineering hand-book. The pertinent information for a particular airway can be fed to the computer either on a standard punched card, or by typing directly into the computer at a remote terminal teletype unit.

By J. A. C. Diering

The simulation of mining in faulted ground was recently described by Crouch. His method is extended here to enable a wide range of non-homogeneous mining problems to be modelled. Essentially, the boundary conditions at geological interfaces are incorporated into the overall iterative solution, which is necessary if faults and joints are to be modelled realistically. Two examples are given to demonstrate the method: the mining of coal a seam below a thick dolerite sill, and the mining of a flat reef in close proximity to a vertical fault where hangingwall and footwall rocks have different properties.

Jan 1, 1980