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By C. A. Cousins

Platinoids in the Witwatersrand system C. A. Cousins. (visitor) Study of the composition, nature and mode of occurrence of platinoid minerals in the conglomerates of the Witwatersrand System leads to some interesting conclusions. Genetic evidence strongly favours a placer origin, while comparison with modern alluvial platinoids supports this view but also indicates that they are very mature alluvials. The compositional patterns and distribution of the platinoids in the Witwatersrand basin suggest the water was saline. Study of the mineralogy was greatly facilitated by the electron-probe.

By R. J. Mason

Background to the Transvaal Iron Age-new discoveries at Olifantspoort and Broederstroom R. J. MASON*, Ph.D. (Visitor) The work being done on Iron Age sites in the Transvaal is described, with particular reference to the finds at Olifantspoort and Broederstroom. The material so far found provides evidence for the production of iron and copper, the farming of cattle and sheep, and the construction of large villages by people who were probably ancestral to the present Bantu population. The material dates from as early as A.D. 270, but clear indications occur from AD. 460 onwards.

Jan 1, 1974

By D. A. Viljoen

An account is given of the development of man's interest in the recovery and working of minerals from Palaeolithic times to the present. This is followed by a discussion of future production trends for the more important minerals, and of likely technological developments in the recovery of various minerals. The crucial importance of energy minerals is stressed, as are several other factors of significance to a flourishing minerals industry: manpower, education, financial climate, Industrial health and safety, and preservation of the environment.

Jan 1, 1979

Tests were carried out in a Hallimond microflotation cell and a Denver D12 cell on typical residue material from a gold mine in the Orange Free State (South Africa), in which 50 per cent of the kerogen was larger than 100 µm in size. Although kerogen is naturally hydrophobic, the observed unexpectedly poor flotation reponse may be due to occlusion of the kerogen by a slime coating and subsequent depression of the slime by guar gums. The recovery of gold from samples spiked with kerogen increased, with no significant reduction in grades, when a petroleum-based collector and tetrasodiumpyrophosphate (a dispersant) were used.

Jan 1, 1985

By M. J. Nicol, P. Balestra, E. Schalch

A detailed fundamental study has been made of the various factors that influence the partial reactions comprising the electrochemical model of the cementation of gold from cyanide solutions by zinc. The effects of cyanide concentration, pH, agitation, additions of lead, and the presence of various impurity ions on both the anodic dissolution of zinc and the cathodic reduction of gold have been investigated. The results are used to explain the influence of these variables on the rate of cementation, and possible implications of this work for plant practice are discussed.

Jan 1, 1979

By M. J. Daly

Historically, engineers and scientists, particularly those involved in the coal-mining industry, have been slow to adopt statistical methods. However, the need to obtain the maximum information .from expensive exploration and development programmes, and the current focus on total quality management, have led to a change in perceptions if classical statistical and geostatistical methods and their application as planning tools. Some if the underlying issues associated with the generally poor communications between statisticians and engineers/physical scientists, which contribute to some if the misconceptions relating to statistical methods, are discussed The potentially profitable application if a number if statistical techniques in the fields if geological evaluation and mine planning! development is also reviewed, with specific reference to the coal industry.

Jan 1, 1995

By R. K. Brummer

The support of stopes and tunnels in South African gold mines subject to rockburst damage requires special attention. The interaction of a seismic wave with either a stope or a tunnel is subject to a number of variables, namely the distance from the source of the event, the ground velocity, the orientation of the excavation with respect to the direction of the seismic wave, and the geology and fracturing around the excavation. This paper discusses these factors in relation to the support requirements in stopes and tunnels. The need for the integration of hydraulic props with stope support and the use of yielding anchors for tunnel support are emphasized.

Jan 1, 1988

By R. T. Rudd

The impact of slimes-dam formation on water quality and pollution by R. T. RUDD*, B.Sc., AMI (S.A.) CE (Visitor) This paper discusses the mechanics of pollution by slimes dams in the gold- and fluorspar-mining industry, as well as that caused by coal dumps and slurry dams. The effect of coal mining on two typical rivers in Natal is shown and the implications discussed. The implications and trends of sulphates pollution on the Rand Water Barrage in the Vaal River are discussed. The spread of pollutants (sulphates and fluorides) from the Reef and elsewhere, and the impact on urban use and agriculture downstream of the barrage, are illustrated. Conclusions and future policy are outlined.

Jan 12, 1973

By G. M. Bentel, G. E. Blight

The environmentally acceptable disposal of fine-particled mining and industrial wastes by the formation of hydraulic- fill slimes dams is becoming an increasingly important aspect of the total mining endeavour. Relatively little is known of the behaviour of waste slurries during deposition. This paper describes and analyses the following aspects of slurry behaviour: (i) the relationship between viscosity, shear strength, and water content, (ii) the slope assumed by a thickened slurry, (iii) particle-size sorting on a hydraulicfill beach, (iv) gradients of hydraulic-fill beaches, and (v) internal erosion during the deposition of slurry. v083n04p073.pdf

Jan 1, 1983

By H. M. Friede, R. H. Steel

Tin mining and smelting in the Transvaal during the Iron Age by H. M. FRIEDE*. Ph.D. and R. H. STEEL* (Visitors) This paper reviews the historical, archaeological, and metallurgical evidence on Iron Age tin mining and tin smelting in Southern Africa. The results of the analysis of twenty samples of tin ore, tin slag, and tin ingots found associated with Iron Age materials in the Transvaal (mostly in the Rooiberg area) are reported and discussed. The types of ingots preserved in local collections are described. A small experimental tin-smelting furnace was constructed and worked according to traditional African Iron Age technology. Qualitative and quantitative results of this experiment are reported.

Jan 7, 1976

By B. M. Van Vliet

SYNOPSIS This paper outlines the principles involved in the regeneration of activated carbon for renewed use in the recovery of precious metals or the purification of water. While chemical methods are effective in restoring the activity of spent activated carbon containing only single or defined adsorbates, thermal methods have to be used when the spent carbon is loaded with a heterogeneous mixture of adsorbates such as those normally present in industrial process streams or effluents. The steps involved in thermal regeneration are described, together with the operating conditions that can be controlled to give the required degree of activation. Finally, an account is given of the structural changes that occur in a new or spent activated carbon during thermal treatment.

Jan 1, 1991

INTRODUCTION The SAIMM publishes technical information on various aspects of the minerals industry through several different media. (a) Monograph Series Books in the Monograph Series are high quality, detailed discussions on specialized topics. (b) Symposium Series This series consists of the proceedings of international conferences which are held in South Africa. (c) Special Publications Series This series covers titles which do not form part of the Monograph and Symposium Series. (d) The SAIMM Journal Papers published in the Journal cover al relevant areas of technical interest by striving for a balanced content and maintaining a consistently high technical standard. (e) School and Colloquia Notes The papers from al local schools and colloquia are published and handed out at registration. Should authors wish to have their papers considered for publication in the Journal, they should adhere to the guidelines outlined below.

Jan 1, 1991

By S. M. Rupprecht

The transportation of men, material and rock in mechanization programmes is often neglected, or at least plays only a secondary function, as the primary focus is on proving the technology. This is despite recognition of the fact that mechanization is essential if gold mines are to remain competitive. However, the use of totally mechanized systems will require further research in the short to medium term before they become generally available. Thus, there is a real need to improve mechanized men, material and rock transportation systems as they are currently used. This applies to both reef horizons as well as to horizontal transport systems. Keywords: Transportation, rock handling, material handling, men transportation, face cleaning, gully cleaning, continuous scraper, monorail, mechanized raise climber, mechanization.

Sep 1, 2001

1. Book reviews ? Second International Conference on Hydrocyclones. Cranfield (Bedford, MK43 OAT, England), BHRA Fluid Engineering Centre, 1984. £33. Reviewer: R.P. King This volume contains the 28 papers presented at the Second International Conference on Hydrocyclones, which was held in Bath (England) in September 1984. The format and presentation of the papers are similar to those of the first volume in the series, and this volume con¬tinues the series as an authoritative account of much of the research work associated with hydrocyclones that is being undertaken throughout the world. The volume was produced from camera-ready copy supplied by the authors, but the quality of reproduction is very high and both text and figures are legible throughout the volume. Although most of the work reported deals with the hydrocyclone as a classification device, important sections are devoted to liquid-liquid separations and heavy¬medium separations.

Jan 1, 1985

By M. Splaine, C. E. Dohm, S. J. Browner

As the grade of the gold (head grade) in the ore supplied to a reduction plants falls, the efficiency of recovery of the metal drops. This is not simply due to a fixed grade lost in the residue, since the residue grade is itself a function of the head grade. A multi-disciplinary approach was used in the construction of a model to represent the relationship between head grade and recovery efficiency. The model is a physicochemical one based on (i) the reaction characteristics of cyanidation, (ii) the milled-ore selection characteristics of gravity concentration, and (iii) the nearly log normal distribution of gold grades and particle sizes in ore reserves. The model was used to set sound target levels for recovery efficiency for a given head grade at a given plant, against which the performances of the plant equipment can be judged for control purposes.

Jan 1, 1982

New Journals The following three journals may be of interest to readers: Fuel Processing Technology, Process Economics International, Speculations in Science and Technology, MM reports Report no. 2016 Analysis of the NIMROC reference samples for majorelements. Report no. 2018 Supergene aUeration of sulphide ores. II. The effect on the floatability of chalcopyrite, galena, and sphalerite. Report no. 2013 List of unrestricted NI M publications issued from 1966 to 1979. Report no. 2014 The determination by spark-source mass spectrometry, of chlorine and phosphorus in high-purity tungstic oxide. Report no. 2017 Vanadium-bearing titaniferous iron ores from the Rooiwater, Usushwana, Mambula, Kaffirskraal, and Trompsburg Igneous Complexes. Report no. 2022 The determination of thallium and indium in sulphide concentrates. Report no. 2023 Atomic-absorption spectrophotometry with hydride generation: an improved technique. Proceedings Proceedings of the Eleventh Commonwealth Mining and Metallurgical Congress, Hong Kong, 1978. London, Institution of Mining and Metallurgy, 1979. 800 pp. 35,00 or $U.S.77,00.

Jan 1, 1979

By H. M. Friede

A short survey is given of the Iron Age smelting sites and smelting furnaces that have been found in South Africa. An attempt is made to classify South African smelting furnaces by the inclusion of functional characteristics such as the numbers and positions of tuyeres. An affinity is suggested between the Venda (eastern Transvaal) type of furnace and an East African type. The principles of the smelting process in South African Iron Age furnaces and the characteristics of the smelting products are discussed. Results of metallographic and chemical analyses of 19 iron specimens found at South African sites are given and compared with those from sites in Zimbabwe-Rhodesia, Mocambique, and Nigeria. The carburization and steeling of iron during primitive smelting and forging are discussed.

Jan 1, 1979

By S. Venter, W. E. Stumpf

Some of the factors that govern the choice of a nuclear fuel are briefly discussed, special reference being made to the introduction of advanced carbide fuels into fast-breeder programmes. One of these factors, i.e. the compatibility of carbide fuels with stainless-steel cladding, is discussed in depth. A very sensitive technique for the study of compatibility interactions between fuel and cladding is described in respect to the effects of particle size, specific surface area and surface oxidation of the fuel,and microstructure of the cladding on the compatibility behaviour of the cladding with the fuels. Finally, the need for the development of modified or stabilized uranium carbide fuels is discussed, and some results are presented to show the effects of small amounts of sulphur in these fuels on their compatibility with stainless-steel cladding materials.

Jan 1, 1979

By R. T. White

The usual figures quoted for water usage in South African gold mines are 1 ton of water used per ton of rock broken, which represents a consumption of 4000 litres of water every second. Owing to the limited sources under ground water, the high cost of surface-water supplies, and the environmental problems of effluent disposal, water IS recycled continuously for underground use. This paper reviews the various types of water treatment and why water needs to be treated. The uses of lime and some flocculants are considered, since much of the mine service water requires only simple neutralization and clarification. Where mining depths necessitate the installation of underground refrigeration plant, more stringent water requirements must be met, and where plant performance is to be maintained, the prevention of system scaling and corrosion is necessary. The families of chemicals added to provide such protection are outlined, together with a description of the mechanisms of control.

Jan 1, 1985

By R. J. Davidson

The mechanism of gold adsorption on activated charcoal by R. J. DAVIDSON: M.Se., Ph.D. (Rhodes) (Visitor) The adsorption of gold onto activated charcoal is most dependent on the concentration and character of the 'spectator' cations present in the adsorption medium. In the presence of calcium ions, gold is adsorbed as the calcium aurocyanide complex. The degree to which the aurocyanide complexes are adsorbed follows the series Ca> Mt:> H> Li> Na> K, calcium aurocyanide being the most stable complex and potassium aurocyanide the least firmly bound. If a loaded charcoal, where the gold is present as the calcium complex, is treated initially with either sodium carbonate or potassium carbonate solutions, the gold can subsequently be eluted from the charcoal with hot deionized water as either the sodium or the potassium complex respectively. The elution of gold with deionized water appears to be most attractive practically and economically, and has several potential applications in the recovery of gold from dilute solutions.

Jan 10, 1974