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By C. M. G. Wortley

One of the major deliverables of the AMIRA P754 Project, which was sponsored by several major mining companies, was a code of practice and guidelines for metal accounting for the mining and metallurgical industry. These had the objective of improving the auditability and transparency of metal accounting from mine to product, thus assisting in good corporate governance. The overriding objective of mass measurement for metal accounting is to establish the mass of the particular material or component present at a specific time, or the mass flow of that component over a defined time period, to a defined accuracy suitable for metal balancing. As such, it is the first measurement in the chain that includes sampling, sample preparation and analysis, each of which introduces its own errors. Materials often contain moisture, the proportion of which must also be established in order to obtain the dry mass. They may also have to be measured as a volume or mass/mass flow of slurry, or in stockpiles or storage areas, in which case the relative density must be measured. Both the density and moisture measurement often introduce significant error. Whereas a great deal of effort has been directed at sampling, sample preparation and analysis to improve accuracy and establish the error, the same can seldom be said for the mass determination, including the moisture and density measurements. The possible major causes of error are highlighted and methods of reducing them discussed. Mass measurement can be classified into those measurements necessary for custody transfer and primary accounting of the input and output streams to a plant or operation, and measurements required for secondary accounting, or management control. The latter include intra company transfers and plant area performance, and those required for plant control only. This paper is concerned only with primary accounting measurements. The code and best practice state that the equipment should be certified (as sized) as is required for custody transfer. The most accurate and precise of the various possible methods is the static measurement of mass on a weighbridge, platform scale or a weigh bin. If static measurement is not possible, which is often the case for ore fed to a plant, possible alternatives are electromechanical conveyor belt weighers or in-motion weighing of rail trucks. In all cases the material must be adequately sampled to enable a representative moisture content to be determined to calculate the dry mass. Where material is flowing inside conduits, only certain types of the multiplicity of flow meters available may be used and, in the case of slurries, very few flow meters are suitable. As most flow meters measure volume or velocity, the density of the material must also be measured. The basic requirements in order to achieve satisfactory results for the mass, of the component of interest, are listed, as well as common problems and pitfalls encountered in practice. The measurement of the mass of stockpiles and in-plant stocks, often required for metal accounting, is often the largest source of error in metal balances. The reasons for this and methods for reducing and managing the effect are discussed.

Jan 1, 2009

Council for 1995/96 President D.A. J. Ross-Watt President Elect Dr N.A. Barcza Vice Presidents Senior R.P. Mohring Immediate Past President J.A. Cruise Junior J.R. Dixon Honorary Treasurer J.A. Cruise

Jan 1, 1996

Copper cyanide is a common component of cyanide-treatable precious metal ores. The copper concentration in production heaps can be predicted from laboratory column tests, but the exact correlation is not necessarily intuitive. Generally, heap leach operators like to keep copper concentrations in solution below 300?500 ppm and may note problems with gold recovery and cyanide consumption when copper concentrations exceed this amount. There are several methods of copper removal from cyanide solutions including ion exchange; direct electrowinning; acidification, volatilization, and recovery (AVR); and sulphide precipitation such as the sulphidization, acidification, recycling, and thickening (SART) process. SART involves acidification with addition of soluble sulphide, separation of the resulting copper sulphide precipitate, and addition of lime to re-establish alkalinity prior to returning the solution to the leaching process, recovering both copper and cyanide as valuable products. In principle SART is very simple. Yet some SART plants that have been built may have been unnecessarily complex. This paper explores the basics of SART and makes the case for a simple plant design as applied to the heap leaching circuit.

Jan 1, 2012

[COUNCIL FOR 1992/93 President J.P. Hoffman President Elect Dr H. Scott-Russell Vice Presidents Senior J.A. Cruise Immediate Past President R.D. Beck Junior D.A.J. Ross-Watt Honorary Treasurer J.A. Cruise Members of Council Dr N.A. Barcza B.R. Broekman G.A. Brown P.M. Craven Prof. R.J. Dippenaar J.R. Dixon* A.A.B. Douglas B.R. Fleetwood Dr R.V.R. Handfield-Jones P.R. Janisch * co-opted P.J. Knottenbelt R.P. Mohring J.L. Nel* K.C. Owen P.D.K. Robinson K.A. van Gessel D.J. van Niekerk C.J.C.J. van Vuuren* P.M.T. White]

Jan 1, 1993

A manual on mines rescue, safety and gas detection, by J. Strang and P. Mackenzie-Wood. Australia, Austcue, US$25. (Available through Hampo Systems (Pty) Ltd. Reviewer: W. Holding. The book had its origins in a set of notes used by one of the authors for training purposes at the Southern Mines Rescue Station in New South Wales

Jan 1, 1987

By A. D. Thomas, K. C. Wilson

Some years ago, the authors developed an analysis of non-Newtonian pipe flow based on enhanced turbulent microscale and associated sub-layer thickening. This analysis, which can be used for various rheologic modelling equations, has in the past been applied to smooth-walled pipes. The present paper extends the analysis to rough walls, using the popular Bingham plastic equation as a representative rheological behaviour in order to prepare friction-factor plots for comparison with measured results. The conditions for laminar-turbulent transition for both smooth and rough walls are also considered, and comparisons are made with earlier correlations and with experimental data.

Jan 1, 2007

By P. M. Scott

The South African Institute of Mining and Metallurgy held a colloquium on 'The Selection of Equipment for Underground Mining' in Johannesburg on 22nd September, 1982, which, judged by the interest shown, was an unqualified success. Mintek 50 As announced earlier, the Council for Mineral Technology (Mintek) will be celebrating fifty years of growth in 1984 and is organizing an international conference, MINTEK 50, on its areas of special expertise. Drilling Once again the South African Drilling Association will be holding a technical symposium in 1983. ILAFA Congresses The Instituto Latinoamericano del Fierro y el Acero (ILAFA) has scheduled the following congresses for 1983:

Jan 1, 1983

COUNCIL FOR 1989/90 President Dr O.K.H. Steffen President-elect Mr H.G. Mosenthal Senior R.D. Beck Vice Presidents Junior ].P. Hoffman Immediate Past President C.E. Fivaz Honorary Treasurer Dr H. Wagner

Jan 1, 1990

By B. K. Loveday

A model for the leaching of non-porous particles by B. K. LOVEDAY*, Ph.D. (Fellow) A model has been developed for the prediction of the rate of leaching for an assemblage of non-porous particles in terms of size-distribution parameters. Expressions are developed for batch and continuous operation, and an example of the application of the model is given.

Jan 9, 1975

Council for 1998/99 President R.P. Mohring President Elect J.R. Dixon Vice Presidents Senior junior M.H. Rogers Dr L.A. Cramer Immediate Past President Honorary Treasurer Dr N.A. Barcza J.A. Cruise

Jan 1, 1985

[Council for 1993/94 President Dr H. Scott-Russell President Elect J. A. Cruise Vice Presidents Senior D. A. J. Ross-Watt Junior P. D. K. Robinson]

Jan 1, 1994

COUNCIL FOR 1988/89 President C.E. Fivaz President-elect Dr O.K.H. Steffen Senior H.G. Mosenthal Vice Presidents Junior R.D. Beck Immediate Past President B.C. Alberts Honorary Treasurer Dr H. Wagner

Jan 1, 1989

By J. A. L. Napier

An essential requirement for the planning of the global capacity of a mine is a knowledge of the functional relationship between the production level and the capital expenditure necessary to establish that level. An underlying mechanism connecting capital expenditure and mine production capacity is proposed in terms of a characteristic profile of the expenditure that both precedes and succeeds production expansion. By the assignment of a representative shape to this profile, the capital expenditure of individual mines can be modelled. The empirical values describing the characteristic profile are computed for a number of gold mines, and an attempt is made to explain variations in the model coefficients from mine to mine in terms of physical parameters such as shaft depth, shaft concentration, and average rate of depth increase during the life of the mine.

Jan 1, 1981

From its early beginnings, shortly after the Witwatersrand gold rush of 1886, Randfontein Estates was planned as a heavyweight operation. The venture was capitalized by J .B. Robinson to the tune of £2 million at time when syndicates were loath to invest £50000 in ventures in and around the new metropolis, Johannesburg, which had sprung up midway along the Witwatersrand. But by then Robinson was a colossus among his contemporaries. Operating as a loner as he had done on the Kimberley diamond fields, where he created his own individual fortune and commanded the sort of respect which, early in his career, led to his election as Mayor of Kimberley. When news of a third gold discovery in the Transvaal (the first two had been in the Pilgrim's Rest and Barberton areas) reached Kimberley, Robinson's pioneering spirit was further stired and he hastened to the new goldfield to stake his claims before his business adversaries- Rhodes, John X. Meriman, Hans Sauer, and Caldecot-could entrench themselves. Once the new Witwatersrand goldfields had been proclaimed, claimpegging started in earnest. But the question was: where to start? Diamond men al, not one of the financiers had any knowledge of the geology of the gold-bearing formations.

Jan 1, 1989

By G. T. G. Emère

The Harmony Gold Mining Company Limited employs approximately 29 500 people, including 27000 Black workers recruited from areas both within and beyond the boundaries of the Republic of South Africa. The problems arising from the control of this diverse and complex labour force have led to the need for a fully computerized labour control system. This paper describes how, with the aid of an extensive interrelated network of satellite minicomputers, together with ancillary peripheral user terminals and printers, the management of Harmony Gold Mine intends to meet these problems.

Jan 1, 1983

By S. Wakita, K. Aoki, Y. Mito, K. Date

It is of great importance to prevent a leakage of hazardous substances from underground storage plants, because this certainly leads to a fatal disaster for human societies. Therefore, effective grouting system needs to be developed, which can inject cement grout into low-permeable rock masses. Authors have carried out a series of laboratory injection tests using a fracture model and field tests in low-permeable rock masses. In these tests, not only was the superiority of dynamic grouting confirmed, but also the relationship between grouting-efficiency and injection parameters was investigated. In this paper, the results of laboratory injection tests and field tests together with theoretical approaches to them are mentioned. L’empêchement de la fuite des substances dangereuses des galeries de stockage est un traitement très important pour protéger la société humaine contre la comtamination catastrophique. Par conséquent, un procédé d’injection efficace doit être mis au point, qui peut injecter du coulis de ciment dans le rocher ayant une perméabilité basse. Les auteurs ont effectué une série d'essais d'injection en laboratoire en utilisant un modèle de rupture et d'essais sur le terrain dans le rocher ayant une perméabilité basse. Dans ces essais, était non seulement la supériorité du l’injection dynamique confirmée, mais aussi le rapport entre l’efficacité de l’injection et les paramètres d'injection a été étudié. Dans cet article, les résultats des essais d'injection en laboratoire et des essais sur le terrain ainsi que les méthodes théoriques pour les essais sont mentionnés. Es ist wichtig, Durchsickerns gefährlicher Substanzen aus unterirdischen Lagerstellen zu verhindern, weil dies für die menschliche Gesellschaft unter Umständen zu verheerenden Unfällen führen kann. Daher muß ein effizientes VerfugesSystem entwickelt werden, welches erlaubt den Mörtelschlamm in wenig durchlässige Felsenmassen einzuspritzen. Die Autoren haben eine Serie von Laboreinspritzungsversuchen mit einem Bruchmodell und Feldversuche an wenig durchlässigen Felsenmassen durchgeführt. Diese Versuche zeigten nicht nur die Überlegenheit des dynamischen Verfugens, sondern wurde dabei auch das Verhältnis zwischen Verfugen und Leistungsfähigkeit sowie den Einspritzungparametern untersucht. In dieser Studie werden die Ergebnisse der Laboreinspritzungtests und die Feldversuche zusammen mit den entsprechenden theoretischen Ansätzen erläutert.

Jan 1, 2003

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 J. H. Lazarus

The evolution of backfill-distribution systems for deep gold mines is examined. The status of current technology for the design of backfill-distribution systems is considered with reference to pipeline pressure gradients, pipeline wear rates, and slurry flow regimes. The effect of an increase in the relative density of the slurry on the performance of backfill-distribution systems is illustrated. Future trends regarding the design of backfill-distribution systems are discussed.

Jan 1, 1993

By I. J. Barker, D. A. Vetter, G. A. Turner

The modeling of the uranium-leaching process, and the logging of data from a plant for the evaluation of the model, are reported. A phenomenological approach was adopted in the development of the model. A set of eight chemical reactions was chosen to represent the complex chemistry of the process, and kinetic expressions for these reactions were incorporated in differential equations representing mass and energy balances. These equations were coded in FORTRAN to form a program that simulated the process, and that allowed averaged and continuous data from the plant to be compared with the model. This allowed the model to be 'tuned', and to reveal a number of minor

Jan 1, 1989

COUNCIL FOR 1987/88 President B.C. Alberts President-elect C.E. Fivaz Vice Presidents Senior Junior Dr O.K.H. Steffen H.G. Mosenthal Immediate Past President Dr H. Wagner Honorary Treasurer Dr H. Wagner

Jan 1, 1988