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By D. Menne

A comminution model and a quick laboratory milling test procedure are presented. These allow the determination of milling parameters for the - optimization of ball size and pulp density in operating mills estimation of the performance of new feed stocks in an existing mill - estimation of the expected milling performance for a new project. Information on the estimation of the size of mills to deliver specified amounts of comminution energy, and amount of expected ball, rod, and liner wear to allow cost estimates for new projects, is also included.

Jan 1, 1983

By B. R. Broekman, J. P. W. Bennie, P. D. K. Robinson, R. P. Viljoen

The theme of the Congress was 'Resources and Technology', the intention being to highlight those basic technical aspects in the disciplines of geology, mining, extractive metallurgy, and metals technology that are required for successful mineral-based operations. The technical programme covered a fairly broad field, as is appropriate for the CMMI Congress, and was generally considered to be of a high professional standard; informative and, with the exception of some minor hitches, well-run. Parallel sessions were held in the four disciplines. All were well attended, and despite tight presentation schedules, certain valuable discussions developed.

Jan 1, 1994

A colloquium on 'Recent Developments in Wearresistant Materials', organized by the Technical Programme Committee: Physical Metallurgy of the SAIMM, was held at Mintek on 7th May, 1985. After delegates had been welcomed by Dr P.T. Wedepohl, Chairman of the Organizing Committee, Mr J.D. Austin, President of the SAIMM, delivered the opening address. Corrigenda to article on copper* I read with considerable interest the recent articles on copper by Mr C.O. Beale as published in the Journal. However, in Part 11 the section dealing with Prieska Copper Mines (Pty) Limited contained several factual errors, details of which are given below.

Jan 1, 1985

By M. C. Harris

Float-sink analysis has wide application in the coal laboratory. This paper evaluates the established methods used for the float-sink analysis of fine coal, and then describes a new method and apparatus that can be used for material down to a few micrometres in size. The method is rapid and accurate, and requires only a small amount of sample. The results presented show close agreement with the float-sink analyses obtained by the more classical technique using separating columns. The new centrifugal method reduces the time required for the analysis by a factor of ten.

Jan 1, 1986

By W. K. Brinsden

The Australian Institute of Geoscientists (AIG) held their fifth successive annual seminar at Observation City, Scarborough, in Perth on 15th November, 1990. The title of the seminar was 'Strategies for Grade Control'. The Seminar attracted 158 delegates, including 10 speakers. In addition to geoscientists, the attendees included mining engineers, metallurgists, and mining analysts. The welcoming address was given by Rob Duncan, Chairman of the Westem Australian Branch of AIG, who said there is a strong demand for this type of seminar in Western Australia (WA). It helps geoscientists to keep up with former colleagues and to keep abreast of technical developments.

Jan 1, 1991

The First International Symposium on Seismicity in Mines, organized by the South African National Group on Rock Mechanics in collaboration with the South African Institute of Mining and Metallurgy, was held in Randburg (near Johannesburg) from 13th to 17th September, 1982. It was the first attempt to provide an international forum for the consideration of seismic problems specifically affecting mines or associated with mining. Numerical mathematics The South African Society for Numerical Mathematics and the Computer Science Department of the University of Natal are organizing the Ninth Symposium on Numerical Mathematics to be held in Durban from 18th to 20th July, 1983.

Jan 1, 1983

By O. K. H. Steen

Significant political and economic changes have taken place in our society in the past year that are going to impact on our minerals industry, and therefore also on our members. Surely, it is not coincidence that the economic and political changes have occured simultaneously? South Africa, by virtue of its infrastructure and technology, is strategically placed to develop the potential of Africa's mineral wealth. In this address, I give my personal views on the ability of the mining industry to participate in the wider mineral resources of the African continent.

Jan 1, 1989

By J. D. Smit, K. C. Garner, P. C. van Aswegen

The initial results obtained from the implementation of computer-controlled strategy on the milling circuit are reported. An analysis of these results showed that a peak-power pebble-mill controller on a high throughput hardrock wet-milling circuit reduces the stability of the system. It was concluded that the milling circuit should be regarded as a single system in which the measurement of grinding efficiency, circulating load, product size distribution, and feed rate should minimize the product variance and maximize the feed rate according to the grinding power available. Work is proceeding on such a system.

Jan 1, 1980

By M. J. Nicol, G. Cromberge

An account is given of the development of a relatively simple model that describes the kinetics of the absorption of gold cyanide on activated carbon. The model is based on the treatment of the carbon solution interface as a homogeneous boundary across which gold is transported at a rate determined by the rate of mass transport to and from the interface. Rate equations derived from this model describe the results of various kinetic experiments under continuous or batch conditions in the laboratory and on operating pilot and full-scale plants.

Jan 1, 1983

Introduction and Background For many years people were aware of the vast deposits of titaniferous magnetite containing vanadium in the Bushveld Complex. From 1957 onwards some exploitation of this ore was carried out by Minerals Engineering of S.A. (later the Vantra Division of Highveld Steel and Vanadium Corporation Limited), who produced vanadium pentoxide via a roast-leach process. Canadian Institute of Mining and Metallurgy The Finance and Executive Committees of the Canadian Institute of Mining and Metallurgy have agreed that members of SAIMM should be invited to register at all future CIM meetings at the same rate as CIM members.

Jan 1, 1980

Crossroads for Students Students in their matriculation year, whatever their background, have reached a crossroads in their lives: behind them lie the relatively carefree years of childhood; ahead lies the whole of their working lives. Whether those working lives will be rewarding and interesting depends to considerable extent on whether they get 'a good matric' and carry on to some form of further education. IPMI awards 1985 Nominations for the 1985 Awards are now being accepted by the Awards Committee of the International Precious Metals Institute. THE DISTINGUISHED ACHIEVEMENT AWARD was established to recognize important career contributions to the advancement of precious metals, be it technological, economic, or business.

Jan 1, 1984

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

By H. T. Kaiser, P. De Waal

The Alusaf aluminium smelter at Richards Bay by H. T. KAISER, B.Sc. (Pta), M.B.L. (Unisa) (Visitor) and P. DE WAAL, B.Sc., B.lng. (Mech.) (Stell.) (Visitor) A description is given of the aluminium smelter at Richards Bay, which operates on the Hall-Heroult electrolysis principle. The annual output of metal (average 99,7 per cent aluminium) is approximately 7S 000 tons. Since its commissioning in 1971, the plant has fulfilled South Africa's total demand for low-alloy rolling slabs, extrusion billets, remelt ingots, and electrical conductor rod. The plant layout allows for sufficient expansion of its capacity to meet longterm increases in demand.

Jan 7, 1977

By I. E. Lane

Conventional demand management techniques invariably fail to offer optimum control flexibility in an operationally complex gold mining environment. An improved control system for electrical demand management is proposed. The system is designed to provide more effective load scheduling and control strategies by means of a computer aided demand management system (CADMS). The objective of the CADMS is to provide a responsive computational aid and adaptive control system for effective demand management. The system consists of a short term load forecasting module, an interactive load scheduling module, an incentive based electricity cost allocation module and a power management information module.

Jan 1, 1987

By J. D. Wells

An account is given of the planning required for the rehabilitation of land that is to be disturbed by opencast mining, and of the preparation of rehabilitation of land that is to the Inspector of Mines. The plans Include the provisions that are to be made to allow for climatic conditions, land use, vegetation and wildlife, surface-water resources, geology and ground water, soils, land capability, rehabilitation method, location of discard dumps and slurry ponds, pollution control, and costs. . . Monitoring of the operation is the only way that the rehabilitation plan can be improved, and both monitoring and planning are essential when provision is being made for the closure of a mine.

Jan 1, 1986

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 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 L. Dison, J. A. Hahn, G. E. Blight

A system of artificial support for shallow mines is described, analysed, and evaluated. The system can be designed rationally to support a predetermined overburden load, and tests have shown that the design theory gives accurate predictions of strength. The support system, consisting as it does of two basic materials, reinforced granular material and reinforced cemented material, is flexible and can be varied to suit changing requirements of height and load. The system of preloading to the design load by jacking off the roof ensures that the walls are both stiff and prooftested.

Jan 1, 1982

By B. J. Ralph, I. J. Corrans, B. Harris

In the first section, a brief background to the practical and theoretical aspects of bacterial leaching is presented. Descriptions are given of present and potential methods for exploiting bacterial leaching in metal-winning. In the second section, the results of recent research are presented. The aim of this work was to obtain a greater understanding of the mechanism of bacterial leaching of sulphide minerals. Bacteria were observed to catalyse leaching reactions by oxidising ferrous ions to ferric ions, by removing protective films at the mineral surface and by depolarising cathodic areas.

By J. H. Bulloch

A short review is given of the effects of corrosion fatigue on the materials used in pressurized water-reactor vessels. Selected topics such as testing procedures, test data, and mechanisms in simulated environments are discussed. The main fact that emerges is that most of the data on the growth of fatigue cracks reside below the ASME X1 1980 High-R 'Wet' design-code lines, Le. they fall within that specification. Finally, some recent advances in the understanding of the corrosion-fatigue behaviour of such materials in pressurized water reactors are highlighted.

Jan 1, 1987