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By P. Wiesner, H. –M. Stonner

A brief account is given of the influence of sulphuric acid and chloride ions during the recovery of uranium by solvent extraction, followed by a discussion of the settling behaviour of dispersions and models to represent that behaviour. The paper ends with a description of various methods for the recovery of solvent, which is lost in the solvent-extraction process by entrainment and adsorption on solids and by dissolution.

Jan 1, 1982

By G. T. C. Emere, E. C. Hunter

The use of cylindro-conical settlers for the clarification of underground water by E. C. HUNTER- (Associate) G. T. C. EMERE-, B.A. (Hons.) (Keele) (Visitor) This paper analyses the performance of conical settlers on Harmony Gold Mine from 1959 to the present time, and describes the investigation that was undertaken to substantiate and improve the use of conical settlers for a new pump chamber in another part of the mine.

Jan 5, 1977

The 86th Annual General Meeting of the South African Institute of Mining and Metallurgy was held in Kelvin House, Johannesburg, on Wednesday, 17th August, 1983. Professor A. N. Brown (President) was in the chair, and declared the meeting open at 16h05. This account of the proceedings includes only those matters that are not reported under the heading `Annual report and accounts' elsewhere in this issue.

Jan 1, 1983

By J. P. M. Hojem, C. Dimitriou, N. C. Joughin

This paper describes the design and construction of the first experimental underground rockcutting machine from measurements of cutting forces determined in tests on small rock specimens in the workshop. The deficiencies of this design, revealed by stoping with almost identical rockcutting machines, are described. An account is given of the design and construction of further experimental machines incorporating substantial improvements which made them technically feasible for use in production.

At the Annual General Meeting of the Chamber of Mines of South Africa, held in Johannesburg on 29th June, 1982, the following leading members of the mining industry were elected to office for the 1982-1983 term: Mr W. W. Malan President Mr C. T. Fenton Vice-President Mr G. Y. Nisbet Vice President William Wouter Malan was born in Springs on 7th November, 1928, and was educated at the Springs High School and the University of the Witwatersrand, where he obtained a B.8c degree in mining engineering. Diamond Mines. Mr Nisbet became a consulting engineer of the Anglo American Corporation in 1972, and a deputy managing director of the Gold Division in 1974. George Young Kisbet was born in Benoni in 1923 and was educated at Pretoria Boys High and the University of the Witwatersrand. Mintek reports Report 2010D A process for the recovery of rare-earth oxides from monazite. (First published 16th March, 1979). Report 2073D A preliminary investigation of the concentration process at Ucar Minerals Corporation. (First published 19th September, 1980). Report 2092D The recovery of pyrite from gold ore by gravity separation. (First published 28th November, 1980). Report M13 Factors affecting the production of fines during the screening and handling of highcarbon ferromanganese.

Jan 1, 1982

The Annual General Meeting of the South African Institute of Mining and Metallurgy was held in Kelvin House, Johannesburg, on Wednesday, 19th August, 1981. Dr P. R. Jochens (President) was in the chair and declared the meeting open at 4.05 p.m. This account of the proceedings includes only those matters that are not reported under the heading `Annual report and accounts' elsewhere in this issue. Confirmation of the Minutes The minutes of the last Annual General Meeting, which was held on 27th August, 1980, were confirmed as pub¬lished in the September issue of the Journal. Welcome President: I extend a sincere welcome to you all, especially to the following distinguished guests: Mr L. W. P. van den Bosch, President of the Chamber of Mines, and Mrs van den Bosch; Mr J. G. Kirchner, Government Mining Engineer, and Mrs Kirchner; Dr William Ble¬loch; Dr L. Alberts, President of the National Institute for Metallurgy, and Mrs Alberts; Dr C. F. Habis, Presi¬dent of the CSIR, and Mrs Habis; Dr P. J. Hugo, Chief Director of the Minerals Bureau, and Mrs Hugo; Mr D. N. Stuart, General Manager of the Chamber of Mines, and Mrs. Stuart; the Presidents and representatives of other Institutes and their wives; and Honorary Life Fellows of our Institute and their wives.

Jan 1, 1981

By G. T. van Rooyen

Materials for Winding Plant Components By Prof. G. T. van Rooyen (ScD) (MIT). Materials for critical applications such as winding plant components are reviewed in terms of the basic requirements which have to be complied with. It is shown that tensile testing alone is not sufficient and that impact testing also is necessary if the incidence of brittle fracture is to be avoided. As a criterion it is suggested that the brittle transition temperature (B.T.T.) determined by impact testing should in all cases be well below the lowest anticipated service temperature. A number of steels were evaluated by impact testing and it is shown that a small ferrite grain size, obtained either by chemical means such as by the use of appropriate alloying elements in the steel or by means of a quenching heat treatment, is effective in attaining a Iow B.T.T. The speed of strain aging as well as the influence of strain aging on the B.T.T. was also evaluated. On the basis of the results obtained it is recommended that steels for critical applications must conform to an appropriate grade and class of steel according to BS 4360 specification. It is further recommended that such steels be exempted from the customary six-monthly heat treatment prescribed by the Mines and Work Act, Regulation 16,18.

By L. A. Vermeulen, D. D. Howat

New distribution functions are derived to describe the size distribution of grinding elements in ball mils. The formulations are based on the assumption that abrasive as well as impactive interactions occur during bal milling-an assumption that is supported by a large body of experimental evidence. It is shown that the functions can be used in the estimation of the magnitudes of abrasive and impactive components in the total rate of bal wear. The relative magnitudes of the wear components provide a basis for optimization of the chemical and metallurgical properties of the balls in a given milling situation. However, it is contended that these quantities are also useful indicators of the relative intensities of the abrasive and impactive interactions that are operative in the size reduction of mineral particles within ball mils. These quantities can be determined for any industrial ball mil, and their magnitudes provide practical guidelines for mil operation. The theory is used in an analysis of samples of ball charges from two industrial ball mils, and it is also applied to al the data on bal-size distributions found in the literature. The qualitative correlation between the calculated values of the wear components and the reported operating conditions is good for a variety of industrial ball mils, in conformity with the hypothesis that the relative magnitudes of the wear components are related to the milling conditions.

Jan 1, 1986

By T. R. Twiddle

The sequential flotation of copper, lead, and zinc in that order is practised at the Broken Hill Concentrator of the Black Mountain Mineral Development Company (Pty) Limited. The minerals of economic importance are chalcopyrite, galena, and sphalerite, with associated silver. The targets for recovery and grade in the lead and zinc circuits were reached quite readily after start-up, but the copper circuit failed to meet the performance requirements with respect to both recovery' and grade. The original circuit for copper is described, together with the subsequent investigations and modifications that were required to produce acceptable metallurgical results. Circuits for semi-bulk and bulk flotation were tried, and the effect of the oxidation state of the pulp was investigated extensively and found to be all important. Tests were conducted on the depression of lead in the cleaning circuit by the use of sodium dichromate, and on heating with the addition of sulphurous acid. The latter technique was ultimately the more successful. The proportion of fresh to recycle water entering the circuit was shown to be important. The original reagent regime was altered and augmented. A more recent problem has been the contamination of the ore with cemented backfill. The changes that this new condition necessitated are described. Success has been measured by a continuous improvement in the economics of the copper recovery.

Jan 1, 1984

By M. S. Janssen, J. L. Taylor, M. A. Ford, E. B. Viljoen, H. A. Simonsen

The Stilfontein and Buffelsfontein Gold Mines, near Klerksdorp in the Transvaal, had accumulated a large amount of uranium-containing residue and, when the price of uranium rose in the 1970s, consideration was given to the possible recovery of this uranium. Preliminary tests showed that concentration of the uranium prior to leaching would not be economic. However, the pyrite in the residue could be concentrated by flotation, and the flotation concentrate could be roasted to pro¬vide both enough acid for leaching the uranium and a calcine from which the gold could be recovered. The feasibility study showed that a uranium operation of 270 kt per month would be most economically attrac¬tive, and a plant of that size was accordingly designed and built. In the first six years of its existence, the plant treated over 20 Mt of residue and produced about 3,5 kt of uranium oxide. During that time, the plant was con¬tinually being improved to make it more reliable and cost-efficient. This paper analyses the operation of the plant during its first six years from the viewpoints of its mechanical, process, and economic performance. The criteria on which the selection of the process was based are reviewed and compared with the actual performance of the plant, emphasis being placed on the leaching, solid-liquid separation, recovery, and purification stages.

Jan 1, 1987

By S. Poirier, J. -M. Facteau

The gold mine sector is presently facing low gold prices as well as technological challenges. Its competitiveness and survival will depend on new mining methods and equipment to improve ore extraction. In 1999, Natural Resources Canada has invested new funds over a period of three years at CANMET’s Experimental Mine to establish the Narrow-Vein Mining Project. A team of engineers and researchers specialized in mining, mechanics and electronics engineering are working to meet the critical need of ore-extraction technology. CANMET’s programme in mechanization and automation for narrow-vein mining had, prior to 1999, realised several important achievements, many in co-operation with a consortium of mining companies(Soredem). The investment of new funds in this area will contribute to develop technologies to improve the productivity, as well as health and safety conditions of the narrow-vein mining industry. Several important impacts of this project will be monitored. In particular, a database of methods and equipment used in narrow-vein mining is being developed. A key thrust is to identify operators’ needs with respect to the development and automation of mining methods and equipment. Based on those needs, research and development projects will be created. The paper will present the objectives of the narrow-vein mining project and some of the results, including the web site developed to present the results of the project.

Sep 1, 2001

An evaluation was made of the wear and performance characteristics of liter bars, and the cost-life effectiveness of backing materials for rotary-mil liners. In a large run-of-mine mil in which the liter bars were mounted on grid liners of austenitic manganese steel (AMS), the liners had an average life that was five to six times that of equivalent unprotected liners. For a single mil, this is equivalent to annual savings in the cost of materials of up to R320 000, and to a downtime of 100 hours. Of the five materials tested in a large pebble mil grinding quartzitic ore, AMS grids and 'white iron' blocks performed best on a cost-life basis, with possibly improved performance from a real white cast iron. (The 'white iron' was shown by microstructural analysis to contain flake raphite and pearlite, being in reality a grey cast iron.) The high-chromium white iron had by far the longest predicted life, with mild steel a surprising second. Rubber was shown to last well in this type of mil. The wear rates of liners change during their lifetimes. The protective effect of liter bars was clearly illustrated by the reduction of over 40 per cent in the wear rates of the liners when the lifter bars were renewed to a height of 80 mm from a fully worn height of 35 mm.

Jan 1, 1991

The first neutrinos in nature ever detected by man were "caught" in a unique laboratory some 3 km (over 2 miles) underground in one of the world's deepest mine shafts at East Rand Proprietary Mines (ERPM), Boksburg. Only 100 m from where gold is being mined from the rock face a small team of South African and American physicists work on one of the most fascinating and important fundamental research projects that is currently exciting the imagination of the scientific world. Neutrinos are sub-atomic particles just as are protons, neutrons and electrons, but they are unique in that they have neither electric charge nor mass. Cosmic neutrinos travel at the speed of light and penetrate stars and planets. Even a million kilometres of solid lead would not provide a satisfactory shield against them. Stars are believed to "burn" by means of nuclear reactions which produce enormous fluxes of neutrinos. The sun, for example, illuminates the earth with visible light, but also bathes it with neutrinos. After World War II, two American physicists, Profs Frederick Reines and Clyde Cowan, experimenting at a large nuclear reactor, succeeded in obtaining direct evidence of the existence of the laboratory-produced neutrino. It then became very important to establish whether neutrinos also existed in nature. This knowledge would lead to a greater understanding of the forces of nuclear physics, of the behaviour of nuclear particles and, indeed, is also relevant to astrophysics. From the start it was clear that the search for "natural" neutrinos would be difficult. Questions which arose were- * how could they be traced if they were without mass or electric charge? * how could other nuclear particles be screened off? * could these not be wrongly detected, or even prevent accurate detection of neutrinos? Neutrinos were known to be produced along with charged particles, by the reaction of primary cosmic rays with the constituents of the atmosphere. It was also known that when the neutrinos collided with matter, they themselves produced the same type of charged particle which could be detected if the unwanted charged particles from the atmosphere could be screened off. What was needed, therefore, was a laboratory where the particles produced in the atmosphere could be screened out, yet which would receive and detect the particles produced by the neutrons' collision with the matter (solid rock) in the vicinity of the laboratory. This meant that scientists either had to build a laboratory with an enormously thick lead shield for their detection work. . . or they could go as near as possible to the centre of the earth where only charged nuclear particles of the very highest energies could penetrate. ERPM was clearly the most suitable place in the world where so effective a "neutrino trap" could be set. Under more than 3 000 m of solid rock the apparatus for detecting neutrinos is well shielded against unwanted nuclear particles produced in the cosmic radiation which can reach the laboratory only in a steeply vertical trajectory. Other particles are easily stopped by the great thickness of rock. The air-conditioned laboratory is at one end of a 150 m long tunnel, 2,5 m high and wide, blasted from the rock. The electronic recording equipment is housed here, while the rest of the tunnel is filled with the detection system. When a charged particle passes through a detector element, it produces a minute flash of light which is recorded and which triggers a flash-tube array. This then defines the trajectory of the charged particle, which is also recorded on film for analysis. So far 82 neutrinos have been detected, 50 at the present level and 32 at a higher level, and the findings have borne out the physicists' theoretical expectations. In this joint project Profs Reines, J. P. F. Sellschop, Director of the Witwatersrand University's Nuclear Research Unit and M. F. Crouch of the Case-Western Reserve University of Ohio are the Chief Investigators. This unique endeavour has been made possible by financial support from the US Atomic Energy Commission, the University of the Witwatersrand and the Chamber of Mines of South Africa, as well as by the cooperation of the management and men of ERPM.

By J. E. Furze

World-wide hikes in the oil price and the prospect of future scar cities of liquid and gaseous fuels have given enhanced status to the South African coal industry. It is thus understandable that the colloquium held at Wit bank on 3rd and 4th October, 1979, and organized jointly by the South African Institute of Mining and Metallurgy and the South African Coal Processing Society should have attracted more than 400 delegates.

Jan 1, 1979

By H. M. Friede

A study was made of the smelting process in two experimental furnaces patterned on Iron Age furnaces excavated at Melville Koppies Nature Reserve, Johannesburg. In a number of smelting experiments, the influences of air supply, temperature, time of operation, fuel consumption, and other operational factors were investigated. Metallurgical and metallographic aspects of the furnace operation and smelting products are discussed, and the experiments are compared with similar research work conducted in Europe and Africa.

Jan 1, 1984

By J. J. Geldenhuys

The Institute revived a valuable tradition when, on the 19th of March, 1983, it held its first 'annual' banquet in some fifteen years. It was such a sparkling success that it is sure to be held more frequently in future. The success of the occasion was borne out by the fact that the main banqueting hall at the Wanderers Club was filled to capacity, with over four hundred members and guests.

Jan 1, 1983

By Bert Woodhouse

The excursions - Symposium on Ancient Mining and Metallurgy in Southern Africa by BERT WOODHOUSE Excursions add much to any symposium. They enable the participants to see something of the subject matter, and provide an opportunity for informal discussion and for the creation or renewal of friendships. In this respect the Ancient Mining Symposium was well provided for. There were two excursions and both were repeated to cope with the large number of participants.

Jan 1, 1974

By B. H. Sandelowsky

Prehistoric metal-working in South West Africa by B. H. SANDELOWSKY*, Ph.D. (Visitor) This paper describes a three-hundred year old metal-working site at Rehoboth, and makes a plea for information on such sites elsewhere in South West Africa so that they can be investigated. The technique of ore smelting that was used at Rehoboth appears to be different from that practised elsewhere by Bantu peoples before the modern era.

Jan 5, 1974

COLLOQUIUM PRACTICAL APPLICATIONS OF INSTRUMENTATION IN THE MINING AND METALLURGICAL INDUSTRIES Rapporteur: J. Laschinger A colloquium and general meeting of the Institute held jointly with the Instrument and Control Society of Southern Africa at Kelvin House, Johannesburg on 18th October, 1972, had as its theme "Practical Applications of Instrumentation in the Mining and Metallurgical Industries" Dr J. P. Hugo (President) was in the chair and about 200 members and visitors were present.

By A. Whillier

Recovery of energy from the water going down mine shafts by A. WHILLIER, Pr. Eng., Se. D. (M.I.T.) (Fellow) The influence of energy-recovery systems on the rise in temperature of water going down mines is examined. It is concluded that the, cost benefit of such systems, deriving partially from the reduced temperature rise in situations where cold water IS sent underground from surface, would more than justify the installation cost.

Jan 4, 1977