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By A. Smith

The practice of leaving barrier pillars between adjacent longwall panels at The Durban Navigation Collieries (Pty) Ltd (Dumacol) has resulted in a considerable loss of coal reserves. Dumacol has now modified the layout of its longwall panels to allow the concurrent mining of barri9f pillars and the extraction of the longwalls. The Implementation of the new panel layout has increased the percentage extraction of reserves and will result in an extension in the life of the mine. The method of extracting barrier pillars between adjacent longwall panels is described in this paper.

Jan 1, 1985

By C. Pohlandt

A literature survey of methods suitable for the determination of cyanides in process streams and effluents is presented. Of the large number of methods published, 92 are examined in detail, emphasis being placed on the selectivity of the methods, i.e. the extent to which they enable one to distinguish between ionic cyanide and metal-cyanide complexes. Methods designed for the determination of 'total cyanide' (i.e. ionic cyanide as well as coordinated cyanide) are evaluated critically. Other aspects of the methods are also considered, such as sensitivity, accuracy, speed, and freedom from interferences.

Jan 1, 1983

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 M. D. Prendergast

Research into the ferrous metallurgy of Rhodesian Iron Age societies M. D. PRENDERGAST (Visitor) Iron-working was a widespread economic activity in Iron Age Rhodesia, and merits historical and metallurgical investigation. However, the research done so far has been incidental and poorly disseminated. This paper reviews the available evidence and the ways in which it can be interpreted by archaeologists and historical metallurgists. Particular attention is paid to smelting techniques and current metallurgical research, and brief suggestions are made for future research. v074n06p254.pdf

Jan 1, 1974

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

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 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 D. H. Hillhouse, G. Lange

Design features of a deep-level shaft by D. H. HILLHOUSE. Pr. Eng.(Visitor)- and G. LANGE. Pr. Eng.(Fellow) Design and technical features of a large, deep shaft are described, and details of the sinking equipment are given. Special features in shaft steelwork, materials handling, and station layouts are described and illustrated. The details of the precast brattice wall are given, together with the reasons for the separation of all steelwork from the brattice wall. A newly developed device for the location of the shaft conveyances while loading or unloading at underground stations is briefly described and illustrated. The paper concludes with a summary showing the rates of progress and costs for the shaft-sinking operation.

By John Taylor

?Introduction to Black Mountain ?Historical metal accounting practice ?Metal accounting audit ?Feed measurement ?Sample precision ?Concentrate measurment ?Current metal accounting practice ?Further refinements to the metal accounting practice

Jan 1, 2005

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 M. T. G. Davis, J. V. Cleasby, H. J. Wright

Mining practice in the Kimberley Division of De Beers Consolidated Mines Limited by J. V. CLEASBY. B.Sc.. A.R.S.M. (Fellow). H. J. WRIGHT. B.Se.. M.Sc.. (Fellow). And M. T. G. DAVIES. B.Sc. (Visitor) T his paper highlights the changes that are taking place at De Beers Consolidated Mines Limited in mining methods, mechanization, and employment practices. De Beers has four underground mines in Kimberley itself (Dutoitspan, Bultfontein, De Beers, and Wesselton), and two open-cast mines outside Kimberley (Finsch and Koffiefontein). Emphasis is placed on the new method envisaged for Koffiefontein when it becomes an underground mine. The paper also includes notes on chemical drilling and on winding practices.

Jan 12, 1975

Two column flotation cells have been installed as single-stage rougher cleaners at Batu Hijau. The objective was to provide additional residence time in the cleaner circuit to maintain maximum recovery during high mill throughput and high feed grade periods. Installation of the columns has allowed the relatively coarse, well-liberated rougher concentrate and the relatively fine, low-grade scavenger concentrate to be treated separately, improving metallurgical performance in the cleaner circuit. Plant results show that the columns produce a high-grade concentrate at an average stage copper recovery of approximately 80 per cent. There is also indication of increases in both overall plant copper recovery and final concentrate copper grade. In addition, the operability and stability of the cleaner circuit has greatly improved.

Jan 1, 2007

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.

The 89th Annual General Meeting of The South African Institute of Mining and Metallurgy was held at Kelvin House, Johannesburg, on 20th August, 1986. Mr. H. E. James (President) was in the chair and declared the meeting open at 16hoo. Obituaries President: It is my sad duty to announce the deaths of the following members of this Institute: Life Fellow D.L. Carson; Retired Fellows T.K. Adams, G.E. Carlyon, N.M. Holford, D.E. Maclver, C.J. Morgan; Fellows S.K. de Kock, R.R. Porter, Dr G.J. Rees; and Associate Sir Lindesay Clark. As a mark of respect to the memory of the deceased and in sympathy with the bereaved, please rise and observe a moment of silence. Minutes President: The 88th Annual General Meeting of the Institute was held on Wednesday, 14th August, 1985, and the minutes were published in the September 1985 issue of the Journal. The minutes were confirmed.

Jan 1, 1986

By V. P. Kolosyuk, A. M. Bryukhanov

Occurrences of hazardous events (explosions of methane or coal dust, fires, outbursts) have been investigated and presented as a flow of events in time. It has been shown that flows of hazardous events in a long time span are homogeneous, stationary and no-after effect flows and can be considered as stationary Poisson flows. A flow of CH4/coal dust explosions that had happened for the last 27 years in Ukraine was analyzed. The explosions have been statistically processed. Practicability of agreement of statistical and theoretical data on mathematical expectation and mean square deviation of time interval between explosion and the explosion intensity has been stated. Probability of an emergency event in time is expressed through an exponential function, while mathematical expectation of an accident and mean square deviation of time interval between successive explosions are in inverse proportion to the accident intensity. Accident probability for practical purposes can be determined as a product of accident intensity by calculated time interval.

Jan 1, 2003

By R. J. Gordon, N. J. Keys, N. F. Peverett

Photometric sorting of ore on a South African gold mine by N. J. KEYS. B.E. Met. (Queensland) (Visitor). R. J. GORDON. (Visitor). And N. F. PEVERETT. B.Sc. (Eng.) (Wits) (Fellow) This paper concerns the development and application of a high-throughput, multi-stream photometric sorting machine developed for the South African gold mines. It is now believed that this sorter and its progeny may be found suitable for a large proportion of all possible sorting applications. A laser-light source and sensitive photomultiplier are employed in a scanning system to detect light reflected from the surfaces of rocks passing through the sorting zone. Electronic circuitry then analyses the photomultiplier signal, which represents the varying intensity of the reflected light, and produces control signals to actuate the appropriate valves of an array of air-blast rejection devices to remove from the feed certain particles selected by the analysing process. Typical throughput per machine ranges from 50 t/h for a minus 60mm plus 30mm feed to 200 t/h for minus 150mm plus 70mm material.

Jan 9, 1974

By L. Dison

There are many potential uses in gold mining for an initially stiff element of backfill that will yield at a predetermined load and maintain that load to beyond a compression of 30%. Such elements could be used as yielding rib pillars, as replacements for more conventional supporting packs, as con- fining bulkheads for mass backfill, as supports to provide lateral constraint, and load-carrying augmentation to overloaded rock pillars. The paper describes a system of reinforced cemented backfill that can be used to provide the above requirements. The necessary characteristics of the reinforcing and the cemented tailings are described together with the method of design to obtain a predetermined stiffness and yield load. The load-compression characteristics of the reinforced tailings elements are described and the effect of changing various of the design parameters is demonstrated.

Jan 1, 1988

By W. K. Osae

A value assessment model which uses deal objectives, financial and non-financial indicators as a guide to assess value creation in mergers and acquisitions. The extent to which post- merger deal objectives are achieved and the potential benefits derived from mining deals that may not necessarily be financial of nature, but which are necessary to sustain and enhance future performance, were considered. The pre-merger and post-merger performances based on some financial indicators that reflect profitability for shareholders were also used. This value assessment model was used to assess four major deals that have occurred in the South African mining industry since 2003 as part of a postgraduate dissertation. In this paper, the Harmony and ARMgold merger is used as an example of how the model can be applied. The model?s relevance and applicability can also serve as a guideline in developing a framework or holistic guideline in assessing whether mining BEE deals in South Africa create value.

Jan 1, 2011

To the trustees of The SAIMM Scholarship Fund We have audited the annual financial statements of The SAIMM Scholarship Fund set out on pages 587 to 592 for the year ended 30 June 2005. These financial statements are the responsibility of the trustees. Our responsibility is to express an opinion on these financial statements based on our audit. Scope We have conducted our audit in accordance with International Standards on Auditing. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement. An audit includes: examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements, assessing the accounting principles used and significant estimates made by management, and evaluating the overall financial statement presentation. We believe that our audit provides a reasonable basis for our opinion. Audit opinion In our opinion, the financial statements fairly present, in all material respects, the financial position of the trust at 30 June 2005 and the results of its operations and cash flows for the year then ended in accordance with South African Statements of Generally Accepted Accounting Practice.

Jan 1, 2005

By R. Ciccu

This paper examine the optimization of a beneficiation plant for recovering marketable barites from crude ores of different characteristics. The plant, part of a mining complex in Sardinia, consists of a jig section integrated with a flotation line. The problem has been studied using a suitable model of the process, based upon experimental and field data pertaining to both the characteristics of the feed material and the performance of machinery. Data have been automatically processed with the aid of a computer to find the optimum setting of each section, in order to maximize profit for each kind of ore separately fed to the plant. Moreover, the advantages of blending the various concentrates - not all of them individually marketable - are also demonstrated. The overall economic result can be improved provided suitable proportions of each kind of ore are fed to the plant. Such information is fundamental for the long-term planning of exploitation of available reserves, and provides guidelines for further prospecting. The paper illustrates the washability characteristics of the ore's and describes in detail the model adopted. The results of data processing are then presented in the form of computer graphs and discussed. Finally, conclusions are drawn regarding the advantages of resorting to Operations Research as an aid to management.

Jan 1, 1987