Search Documents

By G. H. Morton

The tenth international symposium on the application of computer methods in the mineral industry (APCOM) was held in Johannesburg in April; the first time it had taken place outside North America. In the technical sessions fifty-seven papers were presented, providing a review of current work and including some important original contributions. These papers and a full account of the discussion at the symposium will soon be published in a single volume. The Technical Programme The first session of the symposium included an opening address given by Mr J. W. Shilling, President of the Chamber of Mines of South Africa, and a keynote address by Mr K. F. Lane of the Rio Tinto Corporation Limited. Mr Shilling spoke about the history of the South African mining industry and about some of the work of the Chamber of Mines. He stressed the importance of the symposium in familiarising those in mining with computer applications, and expressed his hope that it would stimulate and inspire scientists and engineers in the effort to develop safer and more economic methods of mining. Mr Lane, talking about economic and financial modelling, gave a fascinating account of the experience of RTZ over the last twelve years. In a very honest appraisal of the substantial progress that had been made, he confessed some disappointment not only in the cost and

Previous investigations of stress conditions under which core discing occurs have concentrated on shear stress as the cause of this phenomenon. In this paper it is suggested that discing initiates as a result of extension strain, which develops in the field of triaxially compressive stress ahead of the borehole end.

Jan 1, 1982

By P. G. Mason, H. T. Brown

Electrowinning of nickel at the Bindura Smelting and Refining Company by H. T. BROWN, B.Sc. (Member) and P. G. MASON, B.Sc. (Member) After a brief discussion of theoretical considerations in the electrowinning of nickel, an account is given of the electrowinning process and plant used at the Bindura Smelting and Refining Company.

Jan 2, 1977

By T. V. Owen

This paper describes the flotation of cassiterite from fine slimes at Rooiberg Tin Limited, and gives an of the Amdel on-line analysis system that was instaled in 1984 to aid in the control of the concentrate The system, which is easy to install and maintain, and which uses X-ray-fluorescence analysis, has improved control, and therefore a better recovery of tin.

Jan 1, 1988

By T. B. S. Giddy

The advantages to be gained from the use of a high-density ion-exchange resin in a uranium recovery circuit are shown. It is concluded that, in existing fluidized-bed plants, the throughput of solution can be increased by up to 40 per cent at the same uranium recovery. Alternatively, the values in the barren solution can be improved at the same flow-rate of solution.

Jan 1, 1980

By H. L. Monro

CONTRIBUTION BYP.J.D.LLOYD The thought-provoking paper by Monro deserves serious consideration. If he is correct, the practice of selling gold forward should cease forthwith. However, similar arguments may well be advanced against the selling forward of many other commodities, and this runs counter to the success of futures markets worldwide. If, indeed, the practice were basically flawed, then such markets should long since have failed.

Jan 1, 1992

By E. J. Boome, A. C. Schmidt

Pert, and how Pert techniques can be used in modern mine management By E. J. Boome, A. C. Schmidt C.A. (S.A.) This paper covers the stages of planning required to be performed and the implementation of the plan from grass roots to the partial completion of the sinking of a mine shaft system. The various steps involved in the planning are also examined in some detail. The experience gained in this project and the conclusions reached convince the authors that Pert Planning is a valuable aid to top management.

By A. P. Van Wyk, G. Pirnaar

The effect of vanadium on the susceptibilities of chromium and chromium-nickel steels to reversible temper embritlement was evaluated. The steels investigated were approximately equivalent to steels of as 970 Grade 708A42 and as 970 Grade 817M40, the major difference being that molybdenum had been replaced by vanadium in various concentrations. It was found that the vanadium had a detrimental effect and, in al the concentrations tested, enhanced the susceptibility to reversible temper embritlement of both the chromium and the chromium-nickel steel. The detrimental role played by vanadium in reversible temper embritlement is explained by a consideration of the effect of vanadium carbide, as well as of free vanadium, in solid solution in ferrite.

Jan 1, 1987

The sixth University of Stelenbosch (US)/University of Cape Town (UCT) Minerals Processing Symposium was held at the University of Cape Town on Friday, 7th August, 1987, and was sponsored by The South African Institute of Mining and Metallurgy (SAIMM). Once again the Symposium attracted a large number of delegates from the mining, metallurgical, and chemical industries. Uranium and electricity A symposium on 'Uranium and Electricity- The Complete Nuclear Fuel Cycle' will be held in Saskatoon, Canada, during 18th to 20th September, 1988. The Symposium is sponsored by the Canadian Nuclear Society. Electric steel The Institute of Metals, organizers of the 3rd European Electric Steel Congress, have announced that this important international event will take place in October 1989 at the Bournemouth International Centre.

Jan 1, 1987

By S. Budavari

On the one-hundredth anniversary of the founding of the South African School of Mines, this paper presents a historical review of the tertiary mining education carried out by the School of Mines in Kimberley and the subsequent institutions in Johannesburg. In addition to recording and evaluating a century of mining education, it describes the current activities of the Department of Mining Engineering at the University of the Witwatersrand, which is believed to be the natural successor to the School of Mines. The comparison of earlier and contemporary academic mining activities reflects a gradual transition from the educational philosophy and objectives of a school of mines to those of a modem university department. In the conclusions, some aspects of the educational effort expended during the past hundred years are briefly highlighted.

Jan 1, 1996

By M. J. A. Leal-Gomes

There is a set of settled ideas in the field of the mechanics of rock mass joints, that need a deep revision, after the last experimental works of several authors. In this paper, this theme is approached under several viewpoints, like the following ones: the essential influence of the mating or mismatching of rock joints on their strength (different strength models are applicable to these two situations, one leading preferably to normal scale effects, and the other to inverse scale effects); Patton's model is a bad formulation of the joint strength, whenever there is a dilation effect in the slidings (actually, the essential consideration of the amplitude of the roughess isn't made by any limit equilibrium model, like Patton's model); the joint strength increases as the width perpendicular to the sliding direction is reduced (previous works of other authors suggested the independence of the strength on that width); the reduction of the anisotropy of the roughness, as the sample symmetry and sample dimensions increase; there is no scale effect in the discontinuity mechanics, if there is no roughness heterogeneity; when only the same roughness and undulation orders are involved in the tests, shorter samples have larger peak displacements and lower shear stiffnesses than larger samples (usually, the contrary is admitted). For all these reasons, there isn't an easy correlation between the small scale tests and the natural large joint scale. Only "in situ" large scale tests have some representativeness. All the above mentioned questions are correlated to each other. Es gibt eine Menge eingewurzelter Ideen im Gebiet der Mechanik von Felsklüften, die, nach den letzten experimentellen Arbeiten von mehreren Verfassern, eine tiefe Überprüfung benötigen. In dieser Mitteilung, wird dieses Thema unter mehreren Blickpunkten angegangen, wie die folgenden: der wesentliche Einfluß des Zusammenpassens oder nicht Zusammenpassens von Gesteinsklüften auf ihre Festigkeit (verschiedene Festigkeitsmodelle sind auf diese zwei Situationen anwendbar, eins, das vorzugsweise zu normalen Maßstabseffekten führt, und das andere, das zu umgekehrten Maßstabseffekten führt); Pattons Modell ist eine schlechte Formulierung der Kluftfestigkeit, immer wenn es einen Dilatationseffekt in den Verschiebungen gibt (in Wahrheit, wird die wesentliche Berücksichtigung der Rauheitsamplitude von keinem Grenzgleichgewichtsmodell beachtet, wie Pattons Modell); die Kluftfestigkeit wächst wenn sich die Breite senkrecht zur Verschiebungsrichtung verringert (frühere Arbeiten anderer Verfasser suggerierten die Unabhängigkeit der Festigkeit von jener Breite); die Verringerung der Rauheitsanisotropìe, wenn die Probekörpersymmetrie und Probekörperabmessungen zunehmen; es gibt keinen Maßstabseffekt auf die Trennflächenmechanik, wenn es keine Rauhheitsheterogenität gibt; wenn nur die gleichen Rauheits- und Ondulationsgrößenordnungen in den Versuchen verwickelt sind, haben kürzere Probekörper größere Spitzenverschiebungen und geringere Schersteifigkeiten als größere Probekörper (gewöhnlich, wird das Gegenteil angenommen). Wegen aller dieser Gründe, gibt es keine einfache Korrelation zwischen den Versuchen im kleinen Maßstab und dem natürlichen großen Kluftmaßstab. Nur "in situ" Versuche im großen Maßstab sind einigermaßen repräsentativ. Alle die oben erwähnten Fragen hängen miteinander zusammen. Il y a un ensemble de des bien établies arrière-pensées idées dans le champ de la mécanique des discontinuités en massifs rocheux qui ont besoin d'une profonde revision, après les derniers travaux de divers auteurs. Dans cet article cette matière est abordée sous divers points de vue, comme les suivants: la signification essentiel de l'ajustement ou du désajustement des discontinuités dans leur résistance. Des différents modèles sont applicables à ces deux situations, une conduisant de préference à des effets d'échelle normaux et l'autre à des effets d'échelle inverses; le modèle de Patton est une mauvaise formulation de la résistance des joints quand il y a effet dilatant dans les glissement. En effet la contribuition essentielle de l'amplitude de la rugosité n'est pas consideré par aucun modèle d'équilibre limite comme le modèle de Patton; la résistance des joints croit au fur et à mesure que la largueur perpendiculaire à la direction de glissement est réduite. Des travaux antérieurs d'autres auteurs suggéraient que la résistance était indépendant de cette largueur; la réduction de l'anisotropie de rugosité au fur et à mesure que la symétrie et les

Jan 1, 2003

By W. K. Brinsden

The Electrometallurgy and Electrochemistry Workshop organized by Dr Ian Corans was held at two venues: .Perth on 9th May, 1990, attended by 30 people . Kalgoorlie on 11th May, 1990, attended by 28 people. The workshop had four speakers: Dr Roger Paul, Director of the Process Chemistry Division at Mintek, who introduced the course with the theory of basic electrochemistry and electrowinning; Dr Peter Spencer of Bactech, who spoke on direct slurry electrolysis; Professor lan Ritchie of Murdoch University, who spoke on Zinc cementation; and Mr. Mike Costelo of Minproc, who gave an address on practical aspects of gold electrowinning in Australia. Dr Paul spoke throughout the first session and shared the remaining sessions with the other speakers.

Jan 1, 1990

By N. C. Joughlin, D. K. Hallbauer

The size distribution and morphology of gold particles in Witwatersrand reefs and their crushed products by D. K. HALLBAUER, Dr. rer. nat., Dipl. Min. (Visitor) and N. C. JOUGHIN, B.Se. (Eng.), Ph.D. (Rand) (Member) Undistorted gold particles were obtained from samples of a variety of Witwatersrand reefs by dissolution of the quartz in hydrofluoric acid. The size distribution of the gold particles and their shapes and association with thucholite and pyrite are discussed. Gold particles with a natural flat, plate-like appearance occur in varying proportion in all reefs. The effect of a number of different comminution processes on the gold particles was investigated, and the shape of gold particles in mill pulp from a number of mines was examined.

By D. B. deur Mostert

This paper was presented at the Coloquium on Management Techniques in the Mining and Metallurgical Industry, which was organized by The South African Institute of Mining and Metallurgy and held in Pretoria during June 1988. The author asks whether technical audits are of any use to management. Technical auditing he defines as an evaluation undertaken by an outsider of whether a technical activity is being carried out correctly. After examining the types of technical auditing, and its prerequisites and procedures, he describes its application in regard to quality, and to production processes and their adequacy. He then answers his question by saying that, not only are technical audits very useful, but they form an essential element in the provision of quality products. In addition, they give management the opportunity of testing whether the activities of the organization are being conducted correctly. This is their most important function in that they alert management to areas of potential growth, modernization, and innovation. However, the use to which technical auditing is put remains the key to its value; that is, its value depends on the positive action that each manager takes as the result of a technical audit.

Jan 1, 1989

By A. J. Reynolds

In recent years, rapid depletion of the higher grade reserves, allied to decreases in paylimits, has led to the exploitation of secondary, erratically mineralized placer horizons on various marginal and low grade gold mines. On Blyvooruitzicht Mine, the rich Carbon Leader Reef has limited reserves, necessitating exploration of the lower grade Middelvlei Reef. This placer has always presented evaluation and exploration problems, to such an extent that it was, at one stage, considered uneconomic. Despite an extensive underground drilling programme no ore reserve targets of reasonable size were apparent. However, when a certain degree of parallelism between sedimentological trends in the Middelvlei Reef and the underlying Carbon Leader was recognized, a meaningful exploration model could be developed. Firstly, all historical sampling records for the Carbon Leader were entered into a computerized system; the database comprised in excess of 340 000 data points. Variables captured consisted of gold value, uranium value, con- glomerate thickness and total reef thickness. The raw data were then averaged into blocks, and plots of different variables were computer-generated for further analysis. This enabled the Carbon Leader to be modelled sedimentologically and, thereby, exploration targets for the Middelvlei Reef were generated, based on the Carbon Leader facies trends. Geostatistical analysis of sampling data in exposed areas of the Middelvlei Reef underground has confirmed the sedimentological breakdown of the placer into distinct facies areas. A facies model relating value distribution patterns to depositional trends, both for the Carbon Leader and the Middelvlei Reef, has thus been incorporated into a mine planning strategy.

Jan 1, 1987

By D. D. Howat

The first joint colloquium between the South African Institute of Mining and Metallurgy and the South African Branch of the Institution of Metallurgists was held in Kelvin House on 23rd April, 1981. About eighty delegates registered, the majority being associated with the local branch of the Institution of Metallurgists. Types of Abrasion and Wear Professor A. Ball, of the University of Cape Town, gave the opening address, which he entitled 'Some Thoughts on Abrasion and Wear'. In his thoughtprovoking talk, he quoted some figures showing that, in the highly industrialized countries, loss by wear and abrasion might amount to about 4 per cent of the gross national product but, in the Republic of South Africa, it was believed to be about 6 per cent of the gross national productprobably associated with the massive influence of mining in our economy. Professor Ball described wear as being of three main types.

Jan 1, 1981

By A. P. Cook

Gas samples were taken from a wide range of target areas on dumps arising from coal mining activities. Some of the dumps had largely burned out, some were still burning, some were in the process of rehabilitation, and on others rehabilitation was essentially complete. It was found that rehabilitation was very effective in reducing emissions to tolerable levels. Even incomplete rehabilitation reduced the CO2 emissions to less than about 1 kg/m2/a, whereas some unrehabilitated areas showed emissions of over 100 kg/m2/a. Some areas where there was active combustion taking place were also sampled, and they showed as much as 7 000 kg/m2/a, but the areas concerned were very small and their total contribution accordingly low. Analyses were also made for SOx, NOx, NH3, and CH4, but these were generally (and unexpectedly) at very low levels. The mines sampled represented 53 per cent of all surface coal mining activity. Accordingly the estimated total emissions were scaled up, to arrive at estimates of 1950 000 ± 350 000 t/a C02, 2040 ± 580 t/a SOx, 306 ± 85t/a NOx, and 31 ± 9 t/a NH3 for all surface mines. Methane was detected only from burning coal, and due to the difficulty in sampling, no reliable estimate could be made of these methane emissions.

Jan 1, 2012

Sedimentary Ores-Ancient and Modern (Revised), edited by C. H. James. Proceedings of the 15th Inter-University Geological Congress. University of Leicester, December, 1967. Special Publication No.1, Department of Geology, University of Leicester, February, 1969. Obtainable from: Leicester University Bookshop, May's Walk, Leicester LE 17 RD. Price: 42s. Postage and packing, 3s. 6d. This volume should be of interest to economic geologists and students in this field. A number of illustrated papers on the genesis of ores in sediments are presented; the authors include experts such as Prof G. C. Amstutz, Dr K. C. Dunham, Prof D. Williams and W. G. GarIick. The papers deal mainly with sulphide deposits, but the late Prof J. H. Taylor's contribution concerns ores of iron and manganese. Brief references to the Witwatersrand ores represent the only discussion of South African deposits. With the notable exception of W. G. Garlick's paper on Zambian copper deposits, the Abstracts given are inadequate, necessitating thorough reading of the papers to extract the important matter.

The South African Institute of Mining and Metallurgy (SAIMM), together with his many friends and colleagues in the mining industry, mourn the loss of one of their most respected and well-loved personalities, Dave Viljoen, who passed away on 23rd June, 1988, in Sevile, Spain.

Jan 1, 1988

By A. M. P. Henderson

Twelve members of the Witbank/Middelburg Branch, on a technical excursion, were hosted by the Technical Department, Pinelands site, of AECI on 10th February, 1989. The tour opened with some well-presented talks on 'Permitted Emulsion Explosives', and the application of the 'French' test to the development detonators.

Jan 1, 1989