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1. Book review Respiratory protection - principles and applications by B. Ballantyne and P. H. Schwa be (Editors). London, Chapman Hall, 1981. (Reviewer: M. J. Martinson) 2. New manual Swedish steel manual, 1981. Available from Jernkontoret, P.O. Box 1721, S-I11 87 Stockholm, Sweden. SEK 85. 3. Publications of the Mineral Policy and Energy Sectors, Canada General review by L. Tibbo. 10 pp. Columbium (niobium) and tantalum by D. G. Fong. 6 pp. Sulphur by B. W. Boyd. 13 pp. Statistical summary of the mineral industry in Canada. 66 tables. Uranium by R. M. Williams. 16 pp. 4. Mintek reports Report 2126 The determination, by microwave techniques, of the interface between pulp and froth. Report 2129 An electrode controller for submerged-arc furnaces. Report 2131 The separation of trace elements in manganese dioxide. Report 2132 The assessment of pellicular anion-exchange resins for the determination of anions by ion chromatography. Report M2 The preparation of two reference materials of South African fluorspar. Report M3 The platinum-group minerals in the UG-2 Layer of the Bushveld Complex at Maandagshoek 254KT.

Jan 1, 1982

By A. J. Roets

Despite its growth over the years, necessitating ever¬larger office accommodation, the Gold Fields group changed its head office address in Johannesburg only twice in 94 years. The first move was at the turn of the century, from the then select suburb of Doornfontein to the corner of Fox and Simmonds Streets. The second move was in the thirties, from that address-now the Reserve Bank building-to the well-known address of 75 Fox Street. With the advent of the first mines of the West Wits Line by the end of the thirties, 75 Fox Street proved too small, and the eastern section of the Commissioner Street side of the present head office was added on. In the fifties, when space once more became a serious problem, the old Exploration building was purchased and demolished, and the present west wing on Commissioner Street was built on the site. In the early seventies, cramped conditions again made life difficult and, despite a reorganization of the interior layouts, the need for expansion remained critical. Eventually, the adjacent Hollard Place and parking area became available, and plans for an extended new building complex could he considered. The building project was

Jan 1, 1985

Notices TRANSPORTATION AND THE ENVIRO NMENT The 5th Quinquennial Convention of the S.A. Institution of Civil Engineers will take place at the Carlton Centre, Johannesburg, from 20th to 24th August, 1973. ENVIRONMENTAL ENGINEERING A conference on environmental engineering problems in industrialized and developing countries is to be held at the United Engineering Centre, New York, on 19th and 20th September, 1973. RABCEWICZ-COLLOQUY The Austrian Society for Geomechanics is to honour Professor Ladislaus V. Rabcewicz, on the occasion of his 80th birthday, with a meeting in Salzburg Congress Hall on 11th and 12th October, 1973. The themes of the four half-day sessions will be as follows. PYRO MET ALL URG ICAL EVENTS IN 1974 Diisseldorf is to be the venue for the following three events: International Iron and Steel Congress O.F.S. Branch Welkom THE MARCH GENERAL MEETING OF THE BRANCH WAS HELD IN THE ST. HELENA CLUB AT 8.00 P.M. ON TUESDAY, 6TH MARCH, 1973 O.F.S. Branch Welkom MINUTES OF A GENERAL MEETING HELD IN THE ST. HELENA CLUB ON WEDNESDAY, 16TH MAY, 1973, AT 8.00 P.M.

By J. H. Selby

The Southern African Institute of Mining and Metallurgy hosted the 6thInternational Heavy Minerals Conference at the Zulu Nyala Game Lodge near Hluhluwe in Zululand, during September 2007. This series of conferences has run for 10 years and has been held on three continents. The interest that has been shown in the conference over the years has demonstrated that the field of heavy minerals is a dynamic and profitable one. It is perhaps appropriate that the tenth conference was held in Zululand, South Africa, where it had its roots. The conference theme was ?back to basics?, and this implied revisiting many of the technologies that made this industry a great one. In doing so, we got a view of how those basic technologies have been put to new applications. There were 39papers accepted for the conference, covering all aspects of the industry. These were presented over a period of four days. This edition of the Conference Proceedings provides the reader with a permanent record of these papers. We hope this volume will join the other five, which this series of conferences has produced, and give a lasting record of the development of our industry.

Jan 1, 2007

By D. Limpitlaw

As coal mining often results in the generation of acid mine drainage (AMD), careful planning and management of the water on such mines is required. A colliery in Mpumalanga recently sponsored independent research into the pollution-ameliorating potential of a natural wetland that has been receiving AMD for at least two decades. Samples of the sediment collected in the wetland were subjected to nine stages of sequential extraction in a determination of the distribution of the metal species present. The samples were then analysed for aluminium, iron, and manganese. The concentrations of sulphate-reducing bacteria (SRB) were also determined. The SRB concentration was found to increase with distance downstream (away from the source of pollution). An analysis of the sediment speciation data indicated that metal immobilization may be optimal in areas where the organic adsorption of metals is at its greatest. The analysis also provided evidence of the biogeochemical improvement of the water quality as the AMD passed through the wetland environment. The metal species present did not correlate strongly with the SRB populations; nor did the soluble species correlate with the species formed over long periods of time.

Jan 1, 1996

The kinetics of cyanide loss were found to be first order under any given set of conditions, allowing rate constants to be easily determined. At room temperature and in the absence of activated carbon, some cyanide is lost by hydrolysis to hydrogen cyanide, but this does not occur to any significant extent at pH values higher than about 10. A higher rate of hydrolysis occurs when air agitation is used. When activated carbon is present, an additional carbon-catalysed oxidation reaction is responsible for a fairly high loss of cyanide. The evidence indicates a reaction mechanism that consumes oxygen and produces cyanate ion. Some of the cyanate thus produced decomposes to form a mixture of ammonia, carbonate, and urea, depending on the solution conditions. Additional cyanide is lost as a result of the adsorption of sodium cyanide by the activated carbon. At high temperatures, an additional hydrolysis reaction, which involves the formation of ammonium formate as an intermediate, occurs an/j is responsible for. a high loss of cyanide, leading ultimately to the formation of ammonia, hydrogen, and carbon dioxide. The presence of activated carbon has no effect on the rate of this reaction.

Jan 1, 1990

The refractoriness of the gold in many of the pyritic ores from the eastern Transvaal is due mainly to the association between the gold and the sulphides, but it can be due to the presence of graphltlc carbonaceous material, which complicates the recovery of the gold by virtue of its adsorption activity. In an examination of the roasting characteristics of three flotation concentrates from the Barberton area, It was found that the gold in the concentrates occurred mostly in two forms: in very fine gold particles distributed within the arsenopyrite, and in a slightly coarser form loosely associated with the pyrite. Direct cyanidation of the concentrates gave gold extractions of from 16 to 30 per cent. After the concentrates had been roasted at temperatures of 650 to 700°C for 20 minutes with rabbling, the extractions varied from 86 to over 90 per cent. Examination of the residues after cyanidation indicated that gold was present in the porous calcines or in the calcined sulphide product. This observation, together with porosity measurements, suggests that physical encapsulation of the gold particles is the main reason for the refractory behaviour of the gold in the calcines.

Jan 1, 1988

By S. Heukelman

Zincor uses O2 enrichment (up to 26% O2 in the fluidizing air) to increase the processing rate of zinc concentrates in the fluidized bed roasters. The aim of this study is to determine whether O2 enrichment can be reduced by introducing micro-pelletized concentrate into the feed blend, while maintaining current roaster feed rates and calcine quality. It was found that, with a load of 20% micro-pellets introduced into the feed blend, that O2 enrichment could be reduced by 60%. It was determined that entrained particles spend on average between 0.46 hour and 2.44 hour in the roaster, compared to particles remaining between 3.93 hour and 4.00 hour in the bed overflow. This compares well with a radioactive tracer test performed by Spira. The required reaction time for micro-pellets was found to be less than the residence time inside a Zincor roaster. The result achieved indicated that the average particle residence time inside the roaster was increased successfully in order to compensate for the longer reaction time required to roast micro-pellets at lower levels of O2 in the fluidizing air.

Jan 1, 2011

By J. A. Maritz

Since the dawn of mining, pillars have been used as primary support to ensure stable workings. Early designs were based on trial and error, after which more scientific means developed over time. A vast amount of progress has been made, especially in soft-rock room-and-pillar design methodologies, from which hard-rock design theories developed with minor changes to constant parameter values. The commonly used Hedley and Grant method for hard rock and Salamon and Munro methodology for soft rock draw on the tributary area associated with the pillar, the width-toheight ratio of the pillar, and a back-analysed strength reduction factor. In these methods, only the vertical stress, or stress normal to the pillar influences the load applied to the pillar. This investigation considers the possible influence of shear stresses on pillars in a room-and-pillar layout in single reef planes and multi-reef environments, based on elastic numerical modelling methods. The possible shear stress poses a safety and financial risk to the design process, whereby an undersized pillar would lead to unstable working conditions, whereas oversized pillars could lead to an under-utilized ore resource.

Jan 1, 2014

By Kym L. Morton

Ground water and associated pore pressure represent elements which can have a negative impact on surface mining and slope stability. Ground water flow and deformation within a slope influence each other. An increase in pore pressure will result in a decrease of effective stress; and conversely if the pore pressure decreases, the effective stress increases. Slope analysis and slope design calculations require good information on pore pressure distribution around an open pit excavation. Until recently very little pore pressure data was available and assumptions had to be used. Location and design of measuring points depend on geological and structural setting, geotechnical domains and practicality. Good planning and the use of sensitive point piezometers to measure in situ pore pressures means that real-time data can be collected and used for the construction of flow nets, the determination of pore pressure distribution around an open pit mine, the validation of the dewatering/depressurization requirements, the calculation of the efficiency of the dewatering system and finally the use of pore pressure data in slope stability analysis. The recommended layout for a monitoring system, types and design of piezometers, data collection and use of the pore pressure data are presented.

Jan 1, 2008

By A. S. Macfarlane

Western Deep Levels (North) is a deeplevel, longwall gold mine. Severe strata control problems and high rates of elastic closure, resulting in high rates of energy release, are associated with mining at depths of up to 3 500 metres. To assist in controlling these aspects of mine design and safety, a waste backfilling system has been designed and commissioned. The integration of such a system into an existing, producing longwall brings many problems of logistics, organization, planning and control. It is the purpose of this paper to examine these aspects of fill management, and to describe some of the practical problems involved with the integration of this project into the mining environment. Although many of the rock mechanics and soil mechanics aspects of backfilling systems are common there are specific problems involved which apply to longwall systems. Very strict guidelines are required for planning personnel to design their backfilling systems for a particular situation. These aspects are examined, and basic models developed which can be used without the necessity of comprehensive input from rock mechanics. A summary of the financial implications is included, and these are examined with regard to possible future applications and expansion of waste filling.

Jan 1, 1988

By J. L. Porter

This paper takes a personal look, through the author?s own experiences, at the implementation of innovations in the narrow-seam, hard-rock mining environment of South Africa?s mining industry over the past 40 years. A number of examples are used to illustrate some of the successes and failures over this period. More importantly, the examples are used to illustrate that the bulk of the investment for these projects should have been applied in a manner that could have achieved more sustainable results. The use of the word ?technology? in this context is also examined, as it is the author?s contention that only measuring the performance of machinery fails to encapsulate the potential of the entire system describing the scope of the innovation being implemented. These experiences and observations are projected onto the current backdrop of upheaval in the relationship between key industry stakeholders and the sustainability challenges facing areas of the mining sector in the South African economy. The paper concludes with some opinions on where attention can be focused in order to develop new thinking that can be applied for the safe and economic extraction of the nation?s mineral wealth.

Jan 1, 2014

By S. V. Mkhatshwa

The purpose of the study was to investigate the factors which affect the performance of the loading and hauling fleet and also find possible solutions to eliminate these factors, so that the daily tonnages required could be produced .This is due to the high demand of manganese required by clients. The investigation strongly focuses on the performances of the three 777D Caterpillar trucks and the R984 C Liebherr Litronic Hydraulic Excavator. In the content of the study, these machines are used to remove and move the low grade manganese (also known as the top cut overburden) in order to expose the high grade manganese from north pit to dump 4. The objectives of the project were to determine the actual performance of the loading and hauling fleet per shift, compare the actual and the theoretical performance and identify areas that need to be improved. To achieve the goals set for the project, a number of activities were carried out. ?Perform a time study to compare the performance of the loading and hauling fleet with the manufacturer specifications ?Match the equipments analysis for Loading and hauling ?Road conditions analysis ?Rolling resistance and Road Gradients analysis ?Operating cost analysis.

Jan 1, 2009

By P. Hand

Most coal plants must run under conditions of varying feed conditions or are asked to produce qualities different from that used in the design. This can cause overloaded conditions as the ?bottlenecks? within the plant, depending on plant operation or as the feed changes. During plant design, geological information can be used to determine washability envelopes and blends that may be expected. Historical data can also be used to develop a size distribution envelope as well as to assign reasonable models for each of the unit processes. In operation, a plant can be sampled to determine changes and to refine process models. The information obtained can then be used in an accurate simulation to define how the plant can deal with the changing environment. This paper uses Limn: The Flowsheet Processor to simulate the coal plant in detail and will produce an accurate model, in terms of equipment sizing as well as water, medium, and solids balance, for each change in feed condition. It will show examples of running the simulation through complete density and size ranges and will determine the equipment required to address each part of the performance envelope.

Jan 1, 2010

Papers of Interest The following papers may be of interest to members. APCOM The Thirteenth International Symposium on the Application of Operation Research and Computer Techniques for Decision Making in the Mineral Industries will be held at the Technical University CIausthaI, Federal Republic of Germany, from 6th to 11th October, 1975.

Jan 1, 1975

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

NOTICE The Institute has received requests for copies of Uranium in South Africa', Vols. 1 and 2, but is unable to supply, as all copies have been sold out. If any members have copies they wish to dispose of it would be appreciated if they would contact the Secretary, P.O. Box 1183, Johannesburg. Telephone 834-1271.

By G. T. G. Emere

With the assistance and encouragement of Mr B.C. Alberts, the Institute's immediate Past President and Iscor's Senior General Manager: Mining, the Committee of the Johannesburg Branch recently organized a two day excursion for members to the northern Transvaal. The itinerary included visits to the Grootegeluk colliery, the Matimba power-generation utility, and the Thabazimbi iron-ore mine.

Jan 1, 1989

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.

This list of corrosion-related terms was compiled to encourage the use of the correct terminology, and to serve as a handy reference for students. It Is based on a similar list compiled by the National Association of Corrosion Engineers (NACE). To promote bilingualism, the Afrikaans terminology is included (in italics at the end of each entry).

Jan 1, 1991