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By K. R. Vost

Calculations are given for the reduction in amplitude and change in phase of the diurnal variation in air temperature as the air flows through a mine. The concrete lining of a typical shaft was found to have a much greater effect than the steelwork. An increase in the conductivity of the concrete, or filling of the steelwork with water, did not have enough effect on the rise in air temperatures underground during the day to justify the costs involved. The steel temperature followed the air temperature much more closely than the concrete temperature did. Calculations are given for the heat stored in steel and concrete during the day.

Jan 1, 1980

By A. W. S. Schumann

SYNOPSIS The most economic exploitation of South African coal resources requires sustained study of the balance between known resources and the predicted rate of consumption, against the background of the development of other sources of energy in South Africa and relevant developments elsewhere in the world. A number of the major issues which would arise in such a study are discussed, including the need for a standardized South African definition for coal resources, the merits of sectoral forecasts of consumption compared with global forecasts, the encouragement of a higher recovery from reserves, and the development of an export market for South African coal.

By M. G. B. Wheeler

SYNOPSIS This report outlines the development of a model to simulate the radiometric sorting of gold- and uranium-bearing ores. The developed program indicates the optimum mass, reject percentage, and expected reject gold and uranium grades for a radiometric sorter. It achieves this by statistical analysis of the data gathered from a large sample of rocks in the required size range for a particular mine. The program can be used in the optimization of existing sorters, as a design tool for new radiometric sorters, and in feasibility studies on radiometric sorting.

Jan 1, 1989

By A. Koursaris, Y. Turan

The object of this study was to investigate the i1Jfluence of nitrogen on the structure and properties of AISI 310S steel. Experimental ingots of the steel with nitrogen contents of up to 0,525 per cent by weight were prepared, hot-rolled, and tested after various treatments. The rollability of the material was adequate. The yield strength, tensile strength, hardness, and fatigue properties of the new alloys improved with increasing nitrogen content. The impact properties improved slightly. Empirical equations were developed for the calculation of the yield and tensile strengths, as well as the difference between these two properties, with increasing nitrogen content.

Jan 1, 1995

By A. Koursaris, Y. N. Turan

This paper reports the results of a literature review carried out on nitrogen-alloyed austenitic stainless steels and their properties. It was found that a large volume of work has been carried out on the subject, particularly with regard to the more common stainless steels such as types 304 and 316. No work appears to have been conducted on the highly alloyed steels such as type 310S. Nitrogen has been found to increase the stability of the austenite in stainless steels and to impart significant improvements in the mechanical and corrosion properties of these alloys. Importantly, nitrogen appears to increase both the ductility and the strength of austenitic stainless steels over a wide range of temperatures.

Jan 1, 1993

By P. C. van Aswegen

The Schools A school on 'Measurement, Process Control and Optimization in the Minerals Industry', organized by The South African Institute of Mining and Metallurgy, was presented twice by course leader Dr Ken Garner, ably assisted by the staff of the Measurement and Control Division of Mintek. The first school was held from 16th to 20th July, 1984, at the University of the Witwatersrand, and the second from 11th to 15th February, 1985, at Mintek. Project development The Sydney Branch of the Australasian Institute of Mining and Metallurgy will hold a second Project Development Symposium in Sydney between 7th and 10th October, 1986. This second symposium will extend the range of topics covered by its predecessor in 1983 to emphasize planning (including strategic planning), construction, and project commissioning.

Jan 1, 1985

By R. Hemp

The first part of this paper describes the collection of barometric pressure measurements in a mine and their statistical analysis, which shows the effect of variations in barometric pressure, both on the primary emissions of methane gas into the workings (whether from fissures or from the surrounding strata), and on the flow of air to and from large unventilated, or poorly ventilated, areas. The second part of the paper deals with a study, based on computer simulations, of leakage flows of air into and out of sealed areas, and the reduction of such flows by the use of adequate seals.

Jan 1, 1994

By Gernot Beer, Christian Dünser, Marcos Noronha

The main findings of the joint research initiative “Numerical Simulation in Tunnelling” and a follow-on project on efficient numerical simulation models for tunnelling are presented. Die wichtigsten Resultate des Forschungsschwerpunkts „Numerische Simulation im Tunnelbau“ und einem Folgeprojekt über effiziente numerische Simulationsmethoden werden präsentiert Les résultats les plus importants du point principal de la recherche "simulation numérique dans la construction de tunnels" et un projet consécutif sur des méthodes de simulation numériques efficaces sont présentés

Jan 1, 2003

The following notes have been compiled to assist authors in the preparation of papers for presentation to the Institute and for publication in the Journal. All papers must meet the standards set by the Council of the Institute, and for this purpose all papers are referred to at least two referees appointed by the Council. Although the worldwide readership of the Journal results in a preference for papers in English, the Council treats papers in Afrikaans on an equal basis, but, to meet the needs of the majority of readers, an English summary of some 5OO to 750 words should be provided.

Jan 1, 1984

By J. P. McDonald, P. L. Mattison, J. M. W. Mackenzie

A variety of processing problems in the hydrometallurgical extraction of uranium in the U.S.A. are contrasted with those in South Africa. In U.S. plants, for example, problems are often encountered in the separation of vanadium, molybdenum, and uranium, and in the contamination of the circuit with organic acids. South African plants often experience problems with dissolved silica in the feed, clarification of feeds, and problems associated with synthetic polyelectrolytes. Individual situations are examined, along with the analytical techniques that assist in solving specific problems. Successful approaches that have been applied to mechanical and chemical problems in' uranium solvent-extraction plants are discussed.

Jan 1, 1981

By L. W. Helle

The investigation, which was conducted at Iscor's Newcastle works (in Natal), was aimed at the development of reliable, consistent, and cost-effective methods of sampling. In the sampling of hot metal, it was found that lollipop and spoon samples had identical sulphur analyses, and negligibly different silicon analyses. Thus, spoon sampling of the hot metal was implemented, with a resultant saving of over RIOO 000 per annum on lollipop samplers. In the sampling of steel, aluminium -killed samples were found to have lower phosphorus analyses than titanium killed samples. Spoon sampling was rejected in this application since the use of titanium wire would be too costly. It was decided that titanium would be used as the deoxidant in lollipop samples of steel, and that the Leco carbon! sulphur analyser would be used as the sole arbiter of sulphur content.

Jan 1, 1983

NIM reports Report no. 1845 The composition and mode of occurrence of gold in Witwatersrand ores and leach residues", Report no. 1861 The determination of some impurities in zirconium metal by instrumental neutronactivation analysis. Report no. 12 Exploratory tests on the concentration of tin ore from Kuils River, C.P. (29th Apr., 1966; re-issued Aug. 1976). Report no. 286 A mineralogical and petrographic study of the pre- Transvaal rocks in Borehole K.l, Koster district, western Transvaal. (15th Feb., 1966; re-issued Jun. 1976). Report no. 938 Life test on IRA 400 resin during the recovery of zinc chloride. (27th Mar., 1970; reissued Aug. 1976). Report no. 1010 The leaching, with hydrofluoric acid, of materials containing tantalum and niobium. (8th Jul., 1970; reissued Aug. 1976).

Jan 12, 1976

Historical Background. South Africa's industrial history began with the discovery of gold and diamonds during the last century, and the mining industry was the first chief component of our technological development. During the past six decades, quantum leaps were made in other fields, too, when other industries and research bodies such as Escom, NDC, Iscor, Sasol, Foskor, Alusaf, Mintek, cs I R, SA B S, and A E C were established. These meaningful additions have two outstanding characteristics. Firstly, they were linked mainly to primary activities such as energy and minerals and, secondly, their establishment was to a large extent due to the driving force of individuals such as Van der Bijl, Van Eck, Rossouw, Schonland, and Roux, rather than to impersonal government policy. Encouraging signs of the evolution of such policy has emerged during the past few years.

Jan 1, 1989

By F. P. A. Robinson, C. R. Thomas

Stress-corrosion studies on materials used for surgical implants * by C. R. THOMAS and F. P. A. ROBINSON Samples of Vitallium (a cobalt-chromium alloy), 316L stainless steel, and titanium T318 were subjected to the boiling magnesium chloride test so thattheir susceptibility to stress-corrosion cracking could be determined, and their behaviour under service conditions was then assessed. Stress-corrosion cracking was confined to the stainless-steel samples, while gross pitting was detected in the samples of forged Vitallium. It was concluded that the use of stainless steel should be avoided for long-term surgical implants. Surface imperfections on the stainless steel are generally the cause of pitting, from which stress-corrosion cracks are sometimes propagated.

Jan 11, 1976

By G. R. Marchant, B. K. Loveday

A mathematical model has been developed for flotation circuit simulation. This model was designed to investigate the effect of varying the circulating loads and to determine whether an improvement in overall efficiency could be gained by a size separation prior to flotation. Model parameters were obtained by regression to plant data. Highly correlated parameters in the model were combined to reduce the number of parameters so that the need for excessive data gathering was eliminated. Mass balance smoothing was used to obtain a consistent data set for regression. The results of the simulation indicate that for the same grade of concentrate, an increase in copper recovery of 0.6 per cent may be possible by increasing the circulating loads. The results of the simulation also indicated that recleaning of the plus 200-mesh material may be beneficial.

By A. M. Thyer

Throughout the history of mining, underground fires or explosions have killed many hundreds or thousands of people. Fortunately, the safety record has gradually improved as a result of many people’s work on improving safety standards and work practices. However, fire and explosion still remains a threat in many situations. As a result the UK Mines Inspectorate commissioned a project to study materials used underground and to develop a fire/explosion risk assessment system. Such a system has been developed, following the study of incidents, specified fire resistance criteria, and fire safety practices. The final methodology uses a series of check sheets to identify potential fuels and ignition sources, preventative measures, fire/explosion mitigation systems, and items for inclusion in emergency plans.

Jan 1, 2003

By V. H. R. Brereton

The gold deposits of the farms Lisbon and Berlyn in the Eastern Transvaal by V. C. H. R. BRERETON* (Visitor) This paper describes the discovery and recovery of gold, over a period dating back to the 1870s. on the farms Lisbon and Berlyn, situated approxim ately 1I km north-east of Pilgrims Rest. where mining ceased in July 1971. 99 years after gold was first discovered in the Pilgrims Rest and Sabie districts. Included in the paper are accounts of the discovery and mining operations of the Lisbon-Berlyn Company from 1884 to 1890. The operations of small companies and syndicates. the superficial winning of gold by diggers, and the encouraging reports of four mining engineers in 1890 are also mentioned.

Jan 11, 1973

By A. McCracken

Probabilistic methods for assessing the reliability of engineering systems in mining are the way of the future. So agreed the delegates of a recent short course on the subject, entitled 'Reliability-based Approach in Mining engineering Design'. This was a very successful five-day technical course sponsored by The South African Institute of Mining and Metallurgy and held at Mintek from 7th to 11th March, 1988. The main lecturer for the course was Milton E. Har, Professor of Geotechnical Engineering at the School for Civil Engineering of Purdue University, Indiana, USA. Professor Har was ably assisted by Dr Dirk van Zyl, a former student. Science quiz Teams of pupils from 37 schools within a radius of 12 kilometres of the Council for Mineral Technology (Mintek) competed in a science quiz held by Mintek at its headquarters in Randburg on Tuesday, June 7th, 1988.

Jan 1, 1988

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 batch flotation 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. Report M182 A techno-economic evaluation of five routes for the comminution of gold ores in South Africa. Report M183 The determination of molybdenum and tungsten in resin by X-ray-fluorescence spectrometry. Report M184 The analysis of silicates, ores, slags, and other materials by X-ray-fluorescence spectrometry. Report M188 Determination of relative sensitivity factors for use in spark-source mass spectrometry.

Jan 1, 1985

[Council for 1994/95 President J.A. Cruise President Elect D.A.J. Ross-Watt Vice Presidents Senior P.D.K. Robinson Junior Dr N.A. Barcza Immediate Past President Dr H. Scott-Russell Honorary Treasurer D.A.J. Ross-Watt Members of Council J.P.W. Bennie Dr L.A. Cramer Prof. R.J. Dippenaar J.R. Dixon A.A.B. Douglas F.M.G. Egerton Prof. R.H. Eric B.R. Fleetwood Dr M.A. Ford Dr R.V.R. Handfield-Jones P.J. Knottenbelt R.P. Mohring K.C. Owen M.H. Rogers K.A. van Gessel P.M.T. White]

Jan 1, 1995