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By M. Kirsten, W. H. Botha, M. H. Fox, J. A. Moolman, A. J. Lathwood

Water is a valuable and in many areas a scarce resource. Governmental legislation regulates the environmental impact of water usage and wastewater disposal through the issue of licenses. These requirements mean that hydrometallurgical refineries must ensure that water consumption and water disposal is managed on a continuous basis in order to prevent the repeal of their operating license. Water balances are often overlooked during the design of a hydrometallurgical refinery. Recent changes in environmental legislation have forced both design engineers and operational management to review water use and disposal within these processes. Unlike concentrators where water can easily be recovered by recycling from tailing dams, water introduced into hydrometallurgical refineries becomes contaminated with soluble metals and thus requires pre-treatment prior to disposal. This paper discusses the various concerns that need to be considered during design and operation of hydrometallurgical refineries with respect to the water balance.

Jan 1, 2007

By F. L. D. Cloete

The Relix process is based on direct contact between an ion-exchange resin and undiluted pulp, thus avoiding prior solid-liquid separation. The resin particles float near the surface of the pulp, forming an inverted fluidized bed with the pulp flowing downwards. The basic idea was demonstrated on a full-scale pachuca tank at Stilfontein Gold Mine in 1970, followed by a small-scale demonstration run in a laboratory at the National Institute for Metallurgy. A pilot plant based on a throughput of 60 tons of ore per day was subsequently operated at West Driefontein Gold Mine for several periods over two years. Although the plant proved operable from a mechanical point of view, the metallurgical performance was not up to expectation. The basic cause of the poor metallurgical performace was shown to be backmixing of both the resin and the pulp between stages. The values obtained for resin losses were inconclusive. Further development of resin-in-pulp processes for the recovery of uranium should be focused on the performance of various techniques for the screening of resin from pulp.

Jan 1, 1981

By H. W. Read

The South African platinum industry finds itself in the midst of a rapidly evolving society that is no longer characterized by the apparent stability of the previous decades. The features of this society include increasing global competition, rapid technological innovation, a declining skills pool, major political transformation, a more challenging working environment as the mines reach deeper into the earth?s crust and a greater concern for human welfare. It is therefore axiomatic that new ways will have to be found to engage the all-pervasive change in the mining environment. Although in general terms project management is a universal endeavour for managing change, it takes place in a specific socio-techno-economic environment and geographical setting that gives it a particular context. The argument of this paper explores, analyses and synthesizes the impact of these changes on the emerging project management methodology. In essence, the management of change will inevitably contribute to the emergence of new dilemmas, issues and challenges. The change management process and procedures will also be affected by this change and in response, drive internal change of its own structures and organization. And, therefore, a new paradigm of project management will become apparent. A new project management model will then be proposed to the industry.

Jan 1, 2006

By I. D. Wood

The geostatistical methods given for the estimation of low-ash coal reserves take into account the geological structure of the seam, and consequently give far more reliable results than have been obtained in the past. Confidence limits are given for all the estimates.

Jan 1, 1979

In many practical situations, calculation of the point semivariogram is not necessary. Such a case is analysed in this chapter. The purpose of this analysis is to give a better understanding of the meaning of the mathematical formulae developed in the previous chapters. A similar problem will be studied in Chapter 11, using the point semivariogram.

Jan 1, 1978

For many of us, formal academic education slows abruptly when we leave a tertiary institute of learning. We start applying and connecting newly acquired knowledge with the practicalities of a career, and begin to think in a manner that is technology-oriented. Subsequent vocational advancement is offered by the .many mining and professional journals that circulate through departments, and by conferences and schools that are organized in-house and via the SAIMM and other professional institutions. The importance of these schools cannot be overstated: they combine people and developing technology to the benefit of the industry as a whole.

Jan 1, 1992

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 L. Woollacott, R. P. King

Although several models for the carbon-in-pulp (CIP) or carbon-in-leach (CIL) processes have been published, most of these models do not consider in detail the way in which the carbon phase flows on large-scale plants. This paper illustrates the importance of these details if the CIP or CIL process is to be modeled correctly. An appropriate model, based on population-balance techniques, is then derived. Suitable mathematical techniques for the solution of the model equations are also described. Finally, a method for estimating the model parameters for a full-scale plant is described.

Jan 1, 1990

By Peter Smith

The construction of one of the world's largest goldrecovery plants to treat run-of-mine ore is progressing on schedule at the President Brand Gold Mine in the Orange Free State. Designed to treat 390 kt per month, the plant will recover 96 per cent of the gold from the ore at a capital cost of 160 million rands in terms of January 1983 money. It will replace the existing gold-treatment installation, as well as provide a 30 per cent increase in capacity. Mintek reports Report M161 Improved recoveries of gold from auriferous calcines and pyrites by fine milling. Report M171 The development of a versatile computer programme for the evaluation of batchflotation results. Report M178 The reduction of chromite in a transferred-arc plasma furnace. Report M179 Optimization of an inductively coupled plasma by the simplex method.

Jan 1, 1985

By E. H. R. Schümann, H. Wagner

SYNOPSIS The paper gives a detailed overview of the history of subsidence engineering on South African collieries. Surface displacements resulting from total-seam extraction are discussed, and the important role of local geology is highlighted. It is shown that the differences in subsidence behaviour between South African and European collieries can be attributed to the presence of competent strata in the overburden of South African coal seams. Criteria are given for the prediction of the most important subsidence parameters, and a new model for the simulation of surface subsidence above total-extraction panels is introduced. The final section of the paper deals with the damage to surface structures caused by total-seam extraction. A brief summary of the most important undermining experiments on South African collieries is given, and it is concluded that local experiences of damage compare with those in Europe.

Jan 1, 1991

By A. Chryss, L. Pullum

Shear-thickening suspensions abound throughout the hydraulic conveying industry; at least this is the perception of many engineers running plants where hydraulic conveying is commonplace. In reality, shear thickening behaviour is limited, in the main, to high concentrations of fine particles, including colloidal and biological suspensions, at moderate to high shear rates. In the authors? experience most cases of shear-thickening behaviour have been either simple ?coarse? particle interactions, poor instrumentation techniques, or both. In some cases these were obviously heterogeneous flows, while in others flows that were homogenous, or were thought to be homogenous. Examples, which illustrate this erroneous perception are given. However, the trend towards pastes and complex suspensions that use high concentration carrier fluids means that the underlying slurries for many of these flows may now be truly shear-thickening. Unfortunately, suspensions that might exhibit shear thickening also invariably exhibit slip, or wall-particle depletion. These separate phenomena are difficult to resolve experimentally and many observations of apparent shear-thickening behaviour are in fact obscured or convoluted by slip effects. A method is presented whereby the true flow properties of these high concentration suspensions, and hence accurate prediction of pipeline flows, can be made using a parallel plate rheometer.

Jan 1, 2007

Project evaluation is completed through individual studies covering technical and financial aspects of the mine to market. These studies are completed at various levels of detail depending on where the project evaluation is in the project's life cycle. The competency of the studies varies in relation to the quality of data, level of the skills employed, control, management and reporting structure. The focus of this paper is managing elements of the study, looking at the cost of opportunity to influence the project, against the value added. Selection of the study manager and study teams is central to getting an integrated project evaluation addressing the correct issues completed on time. Retention of key personnel can reduce rework which, in turn, can reduce time and cost impacts. It is important to have a work breakdown structure at the outset so that the study teams have a common numbering and naming system that will integrate areas, equipment, budgets estimates and accounts. Having set up the evaluation groups and provided training in the study procedures, understanding the scope and schedule are vital elements in producing a project evaluation that addresses the opportunities and the risks of the final project. Arriving at an accurate capital budget requires integration of the research controlled through common systems. Project evaluation process must also address how the project is to be delivered.

Jan 1, 2007

The established shared laboratory facilities between the Departments of Metallurgy and Chemical Engineering of the Vaal Triangle Technikon and the University of Potchefstroom are already proving to be a great success.

Jan 1, 1992

By L. B. McRae

The following papers were presented at a seminar that was organized by the SAIMM and held at Mintek during 1991. The occasion was a visit by 12 members of the Committee for Metallurgical Fundamentals of the Verein Deutscher Eisenhitenleute.

Jan 1, 1991

By C. van Loggerenberg, P. E. Venter

The paper covers a wide range of modifications that are of potential interest to the practical coal-preparation engineer. Unfortunately, the paucity of performance data does not permit one to draw conclusions. The authors do not appear to have a clear understanding of the Tramp (or partition) curve concept.

Jan 1, 1992

By R. F. Botha

I want to thank you for inviting me to deliver this, the closing address at the final plenary session of the 15th Congress of the Council of Mining and Metalurgical Institutions. Your Council has an impressive title, and justly so. Consider the expertise, the skill, the capacity, the achievement, that is gathered together here in this room this afternoon.

Jan 1, 1994

By J. L. Taylor

The belt-filtration plant at Chemwes Limited has been in operation for three years. The plant design is discussed. Operational and engineering problem areas are reported, and where possible the modifications or practices that led to their solution are mentioned. Capital and operating costs, together with selected general operating data, are also included.

Jan 1, 1983

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

By W. J. Whiten

Models of cone crushers and vibrating screens are described. These models have been constructed from actual plant data using a systematic model-building technique. Included in this technique is regression analysis using multi-dimensional spline functions. The models have been used too simulate complete crushing plants and hence to design and evaluate a control system for crushing plants.

Papers and Contributions Since the Institute's inception, it had been our practice until some years ago to meet regularly for discussion of new developments, using as a basis a paper read by one of the members. Usually, the Journal issue containing the paper would have been circulated well before the meeting, giving members plenty of time to absorb it and perhaps to prepare contributions. Discussion was generally lively, often controversial. The author always had an opportunity to reply.

Jan 1, 1991