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By D. Menne

An empirical dimensionless correlation is presented that relates system variables to the superficial slip velocity between solid mineral products and an interstitial fluid. The correlation is valid within engineering accuracy for all solids and fluids at all concentrations. The particular usefulness of the correlation is that it provides explicit equations for both slip velocity and voidage.

Jan 1, 1983

By B. C. Alberts

An international conference on 'The Planning and Operation of Open-pit and Strip Mines' was held at University of Pretoria from 9th to 13th April, 1984. The Conference was organized by the Mining Alumni Society the University of Pretoria and The South African Institute Mining and Metallurgy. Delegates of the mining fraternity from all over the world and Southern Africa attended the Conference. These included more than 400 delegates from Australia, Austria, Botswana, Brazil, Canada, Germany, Holland, SWA-Namibia, the United Kingdom, the United States of America, Zimbabwe, and South Africa.

Jan 1, 1984

Discussion of the above paper by G. J. van JAARSVELDt Mr Ortlepp's paper is important, and deals with a subject towards which much controversy and insufficient basic scientific logic, in my opinion, have been directed. He attempts to remedy some of our unscientific popular misconceptions, and for this we thank him. However, I regret to say that experience has shown that some of his statements cannot be allowed to pass unchallenged. Author's reply Mr Van Jaarsveld's contribution is welcome because it provides an opportunity for me to clarify certain points that were perhaps not adequately explained in the paper.

Jan 1, 1979

By P. Stevenson

Correlations for the critical velocity needed to hydraulically convey particles in horizontal, or near-horizontal, pipes are either explicitly dependent upon the shear stress imparted by the fluid upon the surface of the particle bed, or require a velocity and hydraulic diameter. Often such approaches are modified to account for pipe inclination by the introduction of simple factors. However, we assert that the physics that underpins the hydraulic conveying of particles in steep pipes (such as a directionally drilled oil well) is dissimilar to that which governs particle behaviour in horizontal pipes. In steeply inclined systems, a sliding sediment induces an upward counter flow and hence an autogenous contribution to the shear rate. The physics underpinning particle hydraulic conveying in steep systems is explored using the separation results of Laskovski et al.10

Jan 1, 2007

By Siemag Transplan GmbH

At the Hansa Mine in Dortmund, Germany, coarse run-of-mine coal, up to 60 mm in particle size, has been brought to the surface hydraulically from a depth of 850 m since November 1977. Hoisting is done by a three-chamber pipefeeder, by means of which up to 400 t/h can be lifted. The pipefeeder operates without problems, and has so far shown itself to be efficient and reliable. Vertical hoisting can be carried out by water supplied from the surface, from underground, or from a surface water supply in combination with minewater from underground. Water that flows into the mine, which would in any event have to be pumped to the surface, can be utilized for hoisting operations. The energy costs per ton of coal for a lifting height of 850 m vary between 41 and 62 South African cents, and therefore lie within the range of costs that apply to conventional hoisting.

Jan 1, 1980

Book review HOEK, E., and BRAY, J. Rockslope engineering. London, The Institution of Mining and Metallurgy, 1974. £5. NIM reports Report no. 1625 The determination of uranium and thorium by the use of delayed neutrons. Report no. 1626 Formation constants of zinc chlorocomplexes in perchlorate medium. Report no. 1629 The thermodynamics of the formation of complexes of silver with some substituted pyridines. Report no. 1630 An electrochemical investigation of the dissolution of copper, nickel, and copper-nickel alloys in ammonium carbonate solutions. Report no. 1640 A semi-automatic titrimeter for cyanide analyses. Report no. 1644 Prospects for the recovery of minerals from the sea. 1974 A.S. & T.S. National Award Professor D. C. Midgley, President of the Associated Scientific and Technical Societies of South Africa, today announced the winner of the 1974 A.S. & T.S. National Award. 1974 G.W. en T.V. Nasionale Toekenning Professor D. C. Midgley, President van die Geassosieerde Wetenskaplike en Tegniese Verenigings van Suid- Afrika het vandag die wenner van die 1974 G.W. & T.V. Nasionale Toekenning aangekondig.

Jan 9, 1974

By A. A. Hazell

Mine management by objectives By A. A. HAZELL The author discusses the objective areas of mine management. Setting objectives is seen to be a conscious process which starts at the highest level of management. This enables clear objectives to be set at each lower management level. The methods of setting objectives in the areas of stope production, productivity and manager performance are set out in detail. In the area of manager performance emphasis must be placed on the practice of management. It is concluded from results obtained that "management by objectives" produces better than average perormances.

Reviewer: R. Graham The chemistry of gold extraction by John Marsden and lain House. Elis Horwood Series in Metals and Associated Materials. Chichester, Elis Horwood. £80. The chronology has been well researched, and the book defines al the milestones. It is a pity that there is no map of the early gold finds in South Africa, which would have offered a comparison with those shown of Australia and the USA. Nevertheless, the 'Pre-cyanidation, Cyanidation and Technical Development' eras fall logically into place, and reflect on the advances in social history and civilization, as well as in technology.

Jan 1, 1992

By V. M. Lovell, N. P. Finkelstein

Fundamental studies of the flotation process: The work of the National I nstitute of Metallurgy N. P. Flnkelsteln and V. M. Love Presented at the Colloquim on Flotation, March 1972, and published in the Journal, July, 1972. AUTHORS' REPLY TO DISCUSSION In his contribution to our paper Dr Lloyd makes two criticisms: The first criticism, as we interpret it, is that the agglomerate flotation process that we described is not really necessary because previously described processes effect almost the same results or could be made to give the same results by including sufficient paraffin in the reagent combination.

n interesting situation arose last week when two Vaal River residents wrote to me (and a third telephoned) giving me details of how Sasol wanted to develop an open-cast coal mine on the south bank of the Vaal, just upstream of the Barrage. This is agricultural land and is across the river from Millionaire?s Row, where a number of wealthy people have built river-side mansions. The mine would be hidden by a 30 m-high (10 storeys) earth wall set 300 m back from the edge of the river. It could operate 24 hours a day.

Jan 1, 1996

By R. Hutchings

The paper reviews current understanding of the effect of ion implantation on the wear process, and the state-of-the-art of ion implantation as a commercially viable treatment to impart wear resistance. Ion implantation involves the firing of high-energy ions into the surface of a material, which modifies the surface properties and so causes a transition in the dominant wear mode. The process is best suited to specialized engineering applications involving critical dimensional tolerances or surface finishes, but has gained little industrial acceptance because of its poor reproducibility and the lack of a suitable method of inspection.

Jan 1, 1986

By J. C. Paynter

A review of copper hydrometallurgy by J. C. PAYNTER, B.Sc. (Chem. Eng.) (Visitor) Copper hydrometallurgy is discussed with special reference to the treatment of chalcopyrite concentrates under South African conditions. The following processes are described and illustrated: Sherritt Gordon's ammonia pressure leachilng, the Arbiter Process, sulphuric acid pressure leaching, roasting processes, the Cymet Process, and the ferric chloride process developed at the National Institute for Metallursy. These processes are then compared with respect to the form of sulphur produced (elemental sulphur or sulphate), the character of the iron product and the handling of different types of ore.

Jan 11, 1973

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 N. Boegman

The meteorological conditions in South Africa are not conducive to the effective dispersion of air pollutants. In the light of this, and because of the magnitude, concentration, and future growth potential of the metallurgical industry, control of air pollution is essential. Methods of abatement are discussed for each branch of the metallurgical Industry, as well as for open-cast mining and bulk ore storage. Some recommendations are made regarding potentially rewarding research and development.

Jan 1, 1978

Book reviews Jones, M. J. (editor). Process engineering of pyrometallurgy. Proceedings of a joint meeting of the Institution of Mining and Metallurgy and the Institution of Chemical Engineers. London, Institution of Mining and Metallurgy, 1974. 105 pp. £6,50. Nim reports Report No. 1656 The analysis of geological samples for trace elements by direct-reading emission spectrometry. Report No. 1669 An assessment of the carbon-rod atomizer for the determination of silver.

Jan 12, 1974

By R. C. O’Ferrall, W. G. Goulding

This paper describes the performance of a Robbins 52R Boxhole Borer from its introduction into the mine in July 1975 until late in 1977. As indicated by the costs involved, the performance has increased considerably and is expected to be even better once further envisaged modifications have been made. The average cost for the first half of 1977 was R275 per metre bored as against an average of R628 for 1975.

Jan 1, 1978

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

By M. C. van Blerck

This paper outlines the tax provisions that became defective in January 1992, which allow a working mine to make tax-deductible contributions to a dedicated environmental body that is itself not subject to tax. Such a body will then provide a source of funding for the mine's future environmental expenditures. It is concluded that the establishment of such environmental bodies is a financially sound, tax-effective route, allowing mines, prospectors, and quarry operators to provide for future environmental rehabilitation.

Jan 1, 1994

NIM Reports Report no. 1549 Thermodynamic and related physicochemical factors pertaining to the production of ferromanganese. A literature survey. Report no. 1568 A computer programme for the estimation of parameters in flotation. Report no. 1571 The commissioning of a directreading spectrometer for the analysis of silicate rocks by use of the graphitepellet technique. Report no. 1582 The construction and testing of a precision calorimeter. Report no. 1587 A preliminary investigation of the flotation of copper-activated sphalerite without the use of collectors.

Jan 2, 1974

By deur R. Dippenaar

'n Kort kursus oar die teorie en praktyk van hittebehandeling is vanaf 29 Junie 1981 tot 3 Julie 1981 in die departement Materiaalkunde en Metallurgiese Ingenieurswese aan die Universiteit van Pretoria aangebied. Die kursus is dour dosente van die departement opgestel en in samewerking met 'n aantal gassprekers aDder beskerming van die Suid-Afrikaanse Instituut vir Mynbou en Metallurgie aangebied. Tunnelling The Third International Symposium on Tunnelling is to be held in Brighton from 7th to 11th June, 1982. Professional development seminars The Department of Mining and Metallurgical Engineering of McGill University is to hold the following seminars during 1981-1982.

Jan 1, 1981