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By H. M. Friede

Mining was a widespread economic activity in the African Iron Age. This paper reviews the available evidence on, the archaeological, historical, ethnological, and technological aspects of early mining in the Transvaal. A number of analyses of ores found at archaeological sites (especially at Broederstroom) are reported, and an interpretation of the analytical results is suggested. Descriptions of Iron Age copper- and tin-mining complexes, and of iron-ore workings, are given, and techniques of Iron Age mining are discussed. The evidence of gold mining in Iron Age Transvaal is examined.

Jan 1, 1980

By C. R. Speers, M. I. Forsyth

The paper describes how stress analyses were used to show the defect of a tunnel's shape on the overstressing potential of its periphery. The best profile was found to be that of a horizontal ellipse, for which there was little significant scaling, permitting temporary support to be incorporated into a permanent tunnel support system. This investigation was followed by the modeling of several support systems for tunnels with a horizontal-ellipse profile, which showed that such a profile can reduce the installed support required for a tunnel of different cross section by an average of 57 per cent.

Jan 1, 1994

By G. B. Lundstrom

SYNOPSIS For some time, Vaal Reefs South has operated blindhole borers successfully as an integral part of the mining cycle of operations. To date, over 13 000 m of mechanized boxholing has been completed, and from time to time impressive performances have been achieved. The paper describes the machines, the modus operandi, and the structure of the boring organization at the Mine, with some of the results recorded. The Mine recently took delivery of two new machines with interesting design features. The introduction and early experiences with these two machines are also described.

Jan 1, 1985

By M. Reuter

This paper gives an overview of some criteria for the selection of processes for the recovery of lead and zinc from various raw materials and/or intermediate products. A glossary of possible processes and process variants, is presented and discussed, as well as the way in which these are interlinked. Recent developments in metallurgical process synthesis are also discussed, and the results produced by an eco-techno-.economic synthesis procedure for process routes in zinc metallurgy are given briefly. The way in which such a synthesis can complement a life-cycle assessment (LCA) of zinc-producing technologies is also described.

Jan 1, 1997

By A. K. Haines

The status of the South African research and development programme on continuous ion exchange, which was aimed at the technical and economic assessment of that process for the recovery of uranium, is reviewed. The first phase of this programme, which has now been completed, involved development investigations on various pilot plants and culminated in the successful operation of a large-scale demonstration plant and the incorporation of the system in a number of new South African uranium plants. This account highlights the engineering aspects and the design fo the system, its adaptation to process flowsheets, and plans for future development.

Jan 1, 1978

By H. M. Friede, R. H. Steel

Tin mining and smelting in the Transvaal during the Iron Age by H. M. FRIEDE*. Ph.D. and R. H. STEEL* (Visitors) This paper reviews the historical, archaeological, and metallurgical evidence on Iron Age tin mining and tin smelting in Southern Africa. The results of the analysis of twenty samples of tin ore, tin slag, and tin ingots found associated with Iron Age materials in the Transvaal (mostly in the Rooiberg area) are reported and discussed. The types of ingots preserved in local collections are described. A small experimental tin-smelting furnace was constructed and worked according to traditional African Iron Age technology. Qualitative and quantitative results of this experiment are reported.

Jan 7, 1976

By R. D. Hancock

The complex responsible for the poisoning of anion-exchange resins is identified as the anionic cobaltic penta¬cyanide mono aquo species. It is shown that, at high concentration, this species polymerizes in solutions of pH less than 9. A mechanism for poisoning is presented that involves adsorption of anionic cobalt cyanide by a normal ion-exchange process, followed by polymerization within the resin matrix to form complexes that are too large to diffuse readily through the resin pores. The effects of resin structure and functionality on the extent of cobalt poisoning are examined, and the effect of cobalt poisoning on the kinetics and equilibrium loading of uranium is discussed.

Jan 1, 1979

PREFACE During the past year, considerable effort was devoted to the implementation of the strategic plan that was adopted by the SAIMM in 1986. Good progress was made in a number of areas, while in others the foundation was laid for future progress. Key Objective of the Institute The key objective of the SAIMM is as follows: To identify the needs of its members and to initiate and give effect to the means whereby the requirements for technology and scientific knowledge of the minerals and metals section of the South African economy are satisfied; and to represent and promote the interests of its members.

Jan 1, 1987

By H. M. Friede

An experimental study of iron-smelting techniques used in the South African Iron Age by H. M. FRIEDE, Ph.D. and R. H. STEEL (Visitors) The main factors involved in the primitive smelting of iron (ore, charcoal, temperature, air supply, process control) were evaluated in an experimental furnace that was constructed to the pattern of an Iron Age furnace found at Melville Koppies Nature Reserve, Johannesburg. In particular, the characteristics, action, and efficiency of skin bellows were investigated to gaina better understanding of the air-supply system used. Sixteen specimens of iron ore, slag, and metallic iron (excavated material and material produced in the experimental furnace) were submitted to analysis. The results of the analyses are reported and discussed.

Jan 6, 1977

By B. Jack, A. Vervoort

During pillar extraction, sidewall fracturing and spalling at some collieries constitute a severe stratacontrol problem. In order to obtain a better understanding of this phenomenon, a survey of pillar corner conditions before and during pillar extraction was conducted at one particular site. For the various successive mining steps, the vertical stresses on the pillar corners were calculated by use of a three-dimensional boundary element program. A significant correlation was found between the calculated vertical stress prior to the extraction of the panel and the sidewall conditions. During the extraction of the panel, a significant deterioration of the sidewall conditions at a pillar occurred only when the adjacent pillar was mined, causing an increase in vertical stress on the remaining pillar.

Jan 1, 1992

Minerals and Manpower - PRESIDENTIAL ADDRESS given by R. P. Plewman, Pr. Eng., B.Sc. (Eng) (Wits), M.A. (Oxon.) INTRODUCTION What I want to discuss is the future pattern of manpower in the mining industry, and I should like to begin by examining some relevant statistics. There are four areas that must be examined. Firstly, the future rate of production of different minerals must be estimated. Secondly, an assessment must be made of the balance of different mining technologies likely to be used for each mineral. Thirdly, the manpower requirements for each technology must be determined. And, fourthly, the future manpower resources of the country must be explored. NIM report Report No. 1646 Examination of the methods of analysis for calcium fluoride in fluorspar.

Jan 10, 1974

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 A. Koursaris, Y. N. Turan

A series of experiments was caried out in a vacuum-induction furnace to investigate the solubility of nitrogen in stainless steel type 3100S. Melts were made under constant and variable partial pressures of nitrogen so that the absorption of nitrogen from the atmosphere could be examined. Additions of nitrogenized ferochromium were made to give high nitrogen contents in the steel. Nitrogen contents of up to 0,16 wt per cent were obtained under gaseous atmospheres. With additions of nitrogenized ferochromium, nitrogen contents of up to 0,525 wt per cent were obtained. Comparisons of the later value with existing data indicate that the equilibrium concentration of nitrogen was reached for the experimental conditions used.

Jan 1, 1992

By J. M. Czaplicki

The problems connected with deep mine hoisting and the increasing complexity of this process can be analysed through the application of such mathematical tools as stochastic modelling to study the effectiveness, reliability or safety of hoist methods. To relate these theoretical investigations to real practice, knowledge about components, their stochastic nature and stochastic order of appearance is necessary. This paper presents results obtained during the ten-year (1976-85) period of research undertaken in the Polish mining industry by the Mining Mechanisation Institute of the Silesian Technical University, Gliwice, Poland.

Jan 1, 1987

By T. M. Evers, R. P. Van Den Berg

Ancient mining in Southern Africa, with reference to a copper mine in the Harmony Block, north-eastern Transvaal T. M. EVERS. B.A. (Birm.) (Visitor) and R. P. VAN DEN BERG. B.Sc. (Wits.) (Visitor) A recently discovered mine on the farms Harmony 24 and 25 in the Letaba district has been investigated archaeologically by T. M. Evers and geologically by R. P. van den Berg. The archaeological investigations shed light on the mining techniques and accompanying metallurgical techniques, while the geological investigations give information on the structure and mineralization of the mine. Comparisons with other investigated ancient workings show that mining was well understood in Iron Age times, before the African peoples had any contact with Europeans.

Jan 1, 1974

By M. J. U. T. Van Wijngaarden, R. J. Dippenaar, J. M. A. Geldenhuis

The successful application of solid electrolytes in electrochemical cells for high-temperature thermodynamic studies depends to a large extent on an accurate knowledge of the P. value of the electrolyte (the oxygen partial pressure at which the ionic conductivity and n-type electronic conductivity of the electrolyte are equal). Consequently, the P. value of an electrolyte must be determined prior to its use in electrochemical cells. This paper describes the successful application of a coulometric titration technique in the quantitative assessment of the P. values of a commercially available ytria-stabilized zirconia electrolyte that has been used extensively by local investigators. The experimentally determined P. values of the electrolyte are reported and compared with P. values reported in the literature for a similar electrolyte.

Jan 1, 1988

By J. C. Mostert, P. N. Roberts

Electric smelting at Rustenburg Platinum Mines Limited of nickel - copper concentrates containing platinum-group metals By J. C. MOSTERT Pr. Eng.. B.Sc. (Stellenboseh). M.Sc. Met. Eng. (Fellow) and P. N. ROBERTS Pr. Eng.. B.Sc. Eng. (Rand) (Fellow) The processes involved in the smelting in an electric furnace of nickel-copper concentrates containing platinumgroup metals are described. These are concentrate drying, pelletizing, pellet drying, and flux and pellets proportioning, followed by smelting of the concentrate in a submersible-electrode electric furnace, which is discussed in more detail. The furnace matte is blown in a converter to the white-metal stage and is cast in moulds, whilst the slag is granulated, ground, and floated for recovery of valuable metals and afterwards pumped to the tailing dam.

By N. C. Joughin

Potential for the mechanization of stoping in gold mines by N. C. JOUGHIN B.Sc. Eng., Ph.D. (Rand) (Member) The basic requirements for stoping machines are identified first by examination of the mining rates and productivities attained in conventional stoping, and then by examination of a series of problem areas associated with the shape of the reefs, rockbreaking, rockhandling, and the support and design of the machines. Some of the more important machines being developed are described briefly, and their principal features are compared with the basic requirements identified in the first part of the paper. An estimate of the potential demand for the different types of machines is given.

Jan 1, 1976

By P. R. Beeley

Metal founding - a modern perspective The recent development of metal founding is reviewed in the context of basic requirements for the successful manufacture of cil;5ti,ngs.Progress has been related to the two interdependent fields of process technology and product characteristics. . After a brief review of the growth of the traditional industry. various features of the modern industry are discussed. Reference IS made to current trends in process technology and to the introduction of new techniques affecting production engineering, product quality. and the general nature of the industry. Metallurgical aspects of metal founding are considered, and modern techniques for the control of casting conditions are examined. These aspects are related to the structure and quality of cast metal and to the development of newer types of cast material and product.

Jan 9, 1976

By M. Splaine, W. Davidson, D. C. Atkinson

Since 1964, Nchanga Consolidated Copper Mines, Ltd., has been developing and using production scheduling methods for optimizing its metallurgical operations in the short term (up to one year). Medium-range metallurgical planning has been possible only by successive evaluations of a single-year LP. A modified version of Rosenbrock's direct search technique has now been developed to allow multi-year optimization of both mining and metallurgy for medium-range planning. The modifications to the search technique have produced a marked increase in computational efficiency for this heavily constrained problem in many variables and the system is a usable planning tool, given a reasonably powerful computer. The plans are 'optimum' in the sense that they yield the maximum present value of the operations. Each of the resulting five-yearly mine plans forms the basis for further detailed metallurgical evaluation by the established production scheduling system.