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By H. J. Swanepoel, N. B. Strydom

Groups of up to twelve new recruits to the industry were subjected to climatic room acclimatization for either five, seven, eight or nine days prior to being tested for the degree to which they had been acclimatized. These tests were done at 32,2 0C (wet bulb) at a wind velocity of about 0,4 m/sec and the men worked for four hours at a rate of 215,6 kg m/min on one day and at a rate of 431,2 kg m/min on the second day. The results indicated that there is no significant difference between the degrees of acclimatization obtained by the eight- and nineday procedures which confirms the conculsions drawn in a previous report1. The eight-day procedure can thus be claimed to be perfectly adequate and safe. Decreasing the period of exposure to five or seven days would however, not be justified because of the significant differences in physiological responses that were observed on both test days between men acclimatized for these periods and those acclimatized for nine days. It is concluded that it would be unsafe to employ these shorter periods of acclimatization when underground environmental temperatures at which the men are to work, exceed 31 0C (wet bulb).

By K. I. Afewu, L. C. Woollacott

The design of in-pulp adsorption vessels in the gold industry has, for the most part, been seen as a problem involving the suspension of fine particles o ore in a slurry. The need for the vessel to be designed as a mass-transfer contactor has received insufficient attention. The current series of papers addresses this need The previous paper considered the question of the scale dependence of the film transfer coefficient. This paper examines the mixing considerations that are relevant. A review of the literature and an examination of a limited set of data provide some insight into the mixing conditions needed for the dispersion of the particles of adsorbent. The mixing requirements for the suspension of the ore particles are also considered, and conclusions are drawn in regard to the design of mechanically agitated vessels for gold in-pulp adsorption circuits.

Jan 1, 1995

By R. Guest

Reichert cone concentrators are used successfully in many applications, but have as yet not found favour in the gold mining industry on the Witwatersrand, because, for optimum operation, the cones need to have specially designed feed-preparation and circuit details. In addition, good liberation of the valuable minerals is essential. Gravity tests, in which a pilot plant was used on refractory gold ore, showed that 94 per cent of the gold could be extracted after gravity concentration and preferential grinding, roasting, and cyanidation of the concentrate, whereas 96 per cent could be extracted by flotation followed by the same preferential treatment. However, the capital and operating costs for gravity separation are expected to be considerably lower than those for flotation.

Jan 1, 1982

By N. O. Lotter

Evaluation errors and value frequency distribution models of the gold ore bodies in the Witwatersrand and Free State systems are reviewed. It is found that the low-grade sections of the data are prone to the largest evaluation errors, and that an understanding of the shape of the value frequency distribution is essential to the calculation of mean grade. The evaluation of a mineral process for a particular ore requires attention to mil-feed sampling, sample processing, and monitoring. In particular, the calculation of a representative mass of mill-feed sample (Ms) should take account of size-by-size value variance. Alternative Ms models are discussed.

Jan 1, 1995

By R. R. Mankowski

The work described here is an extension of current theory applied to obtaining the power dissipated at the wavefront of a transverse disturbance traveling along a mine hoisting cable. A previously derived empirical relation is adapted to the present problem, and is solved by use of a Lagrange-type reference frame moving with the wavefront. As a result of tie limitations inherent in the original relation, only a lower-bound for the domain of predicted power losses is defined. A qualitative assessment of conditions leading to the undesirable effects of internal frictional losses at the wavefronts are discussed in terms of the operating environment found on typical mining installations

Jan 1, 1990

By C. Ringas, F. P. A. Robinson

Various theories proposed to account for microbial corrosion are reviewed as a background to a better understanding of this type of corrosion in iron-based alloys. Experimental evidence is presented to show that even stainless-steel alloys are prone to microbial attack by sulphate-reducing bacteria. The corrosive attack by the bacteria is due primarily to the hydrogen sulphide that is produced as part of their metabolic processes.

Jan 1, 1987

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

Infacon 74 Members are reminded of the International Ferro-Alloys Congress that is to take place in Johannesburg between 22nd April and 1st May, 1974. The Congress is being held jointly by the National Institute for Metallurgy, the Ferro Alloy Producers' Association of South Africa, and the South African Institute of Mining and Metallurgy. Correspondence and enquiries should be addressed to The Secretary, Organizing Committee, INFACON 74, Private Bag 7, Auckland Park 2006. The gold deposits of the farms Lisbon and Berlyn in the Eastern Transvaal by v. c. H. R. BRERETON. Published in the Journal November 1973. AUTHOR'S CORRECTIONS The following amendments should be made.

Jan 2, 1974

NEW BOOKLET FOR POTENTIAL ENGINEERS A new booklet "Professional Careers in Engineering" for issue to high school students who are considering engineering as a profession has been prepared for general distribution. The booklet is intended to help high school students to decide whether a career as a professional engineer would appeal to them, and to tell them how to set about becoming a professional engineer. Copies of the booklet may be obtained free of charge by writing to: The Federation of Societies of Professional Engineers, P.O. Box 5907, Johannesburg.

The proceedings of the Centenary Banquet that was held on Friday, 25 March 1994 at The Bal Room of The Carlton at 19:30 follow. Dr H. Scot-Russell The Chemical and Metallurgical Society of South Africa-a forerunner of this Institute-was founded at a meeting held in Johannesburg on the 24th of March, 1894. One of the traditions established early in the life of the Society was the Annual Dinner, which became a major event in Johannesburg's social calendar. It was always attended by people of stature in the industry and in the community, and was usually addressed by a high-ranking Government figure. We are delighted that, on this one hundredth birthday of the Institute, we have been able to continue the tradition. I welcome you, Mr State President, and your charming wife, and we look forward to hearing your address later this evening.

Jan 1, 1994

Notices Competition for Student Members of the South African Institute of Mining and Metallurgy Each year the Institute offers a prize (or prizes should the entries warrant it) of up to Rl00 for the best paper or dissertation on a topic appropriate to the interests of the Institute. The competition is open to all Student Members of the Institute. NEW PUPLICATION Bougainville-the establishment of a copper mine. St. Kilda (Australia), 'Foundations', 1973. The editors of Foundations, Australia's journal of architecture, engineering, and construction, are preparing the above book for publication late in 1973. The story of Bougainville is told and illustrated NIM REPORTS Report No. 1503 Fast-neutron-activation analysis for the determination of oxygen m rock sam ples. Report No. 1514 The determination by X-ray-fluorescence spectrometry of minor amounts of niobium and tantalum in geological materials. Report No. 1530 AUREOL - an X-ray-absorption analyser for the determination of the uranium on loaded resin in ionexchange plants. Report No. 1534 The determination, by atomicabsorption spectrophotometry, of noble metals in the presence of sodium, barium, or sulphate ions. A comparison of uranium and lanthanum as 'releasing agents.

Jan 10, 1973

By R. L. Paul

Although it is often said that South Africa does not have suitable deposits, or the potential to develop mines on a small scale, a recent survey by the Chamber of Mines1 showed that, out of a sample of 641 producers, 41 per cent had between 10 and 19 employees, and a further 29 per cent had between 20 and 29 employees. This goes to show that minerals-related small, medium, and micro-enterprises (SMMEs) do exist, and can play an important role in the development of rural industries in South Africa. Nchaka Moloi of the Department for Mineral and Energy Affairs defined the various categories of SMMEsas shown in Table I2. An enterprise could be placed in a certain category as long as two of the variables, employees, capex or production applied.

Jan 1, 1997

The addition of binder to full plant tailings significantly affects the rheology of a backfill mixture and, consequently, the pressure gradients in the pipeline. The binder increases the yield stress and apparent viscosity of the mixture, and the transition velocity between the laminar and turbulent flow regimes. In a test conducted at a slurry relative density of 1,72 with binder addition, the mixture also exhibited time-dependent behaviour owing to the hydration of the binder.

Jan 1, 1993

By George Kayesa

[ ] A multiple-bench slope failure occurred at Letlhakane mine on 14th July 2005. No injuries or damage to equipment was suffered and mining production was not affected. Slope failure was preceded by the precursors of tension crack formation, crack widening and extension as well as slope monitoring targets movement. It was predicted that slope failure was imminent using the Geomos slope monitoring system, though the timing was not certain. The area to be affected by the slope failure was also known before hand as was the slope failure mode. As a result, measures were taken to avoid exposing personnel and mining equipment to the slope failure risk. This paper discusses how the prediction of the slope failure of 14th July 2005 using the Geomos slope monitoring system resulted into avoiding potentially fatal injury, damage to mining equipment and loss of mining production.

Jan 1, 2006

Cecil John Irving was born on 13th March, 1902. He was educated at King Edward's School in Birmingham, and at the University of Birmingham, where he graduated in B.Sc. Mining Metallurgy in 1922, and in B.Sc. Metal Mining on 7th July, 1923. Johannesburg 1986 The biggest mining exhibition ever held in Africa and several allied international conferences are to be staged in Johannesburg in September of next year.

Jan 1, 1985

By J. C. Coetzee

In this article, a case is made for the importance of the transfer and management of tacit knowledge to ensure continued sustainable competitive advantage within the pyrometallurgical industry in South Africa. The state of knowledge management (KM) is assessed through a theoretical and empirical study. The empirical part of the study was conducted by means of a survey questionnaire. An important prerequisite within the research entailed determining the current state of KM within the pyrometallurgical industry, and the findings are presented throughout this article. The research argues for initiatives to address the high turnover of pyrometallurgical knowledge workers. This industry needs to entrench tacit knowledge and therefore address the problems associated with the continuous loss of inherent specialized knowledge. Appropriately, emphasis is placed on identifying initiatives required to embed and retain not only human capital lost through mobility, but rather retaining tacit knowledge through a practical KM framework.

Jan 1, 2012

By J. C. Coetzee

In this article, a case is made for the importance of the transfer and management of tacit knowledge to ensure continued sustainable competitive advantage within the pyrometallurgical industry in South Africa. The state of knowledge management (KM) is assessed through a theoretical and empirical study. The empirical part of the study was conducted by means of a survey questionnaire. An important prerequisite within the research entailed determining the current state of KM within the pyrometallurgical industry, and the findings are presented throughout this article. The research argues for initiatives to address the high turnover of pyrometallurgical knowledge workers. This industry needs to entrench tacit knowledge and therefore address the problems associated with the continuous loss of inherent specialized knowledge. Appropriately, emphasis is placed on identifying initiatives required to embed and retain not only human capital lost through mobility, but rather retaining tacit knowledge through a practical KM framework.

Jan 1, 2012

By B. P. Christos

The improved rate of stope-face advance at Buffelsfontein Gold Mining Company Limited by B. P. CHRISTOS (Associate) To achieve a higher rate of stope-face advance. it was necessary to examine al.1aspects of the stoping operation, to identify bottlenecks, and to eliminate them or reduce their effect. The cleaning cycle was fund to be the most significant bottleneck. and this problem was aggravated by long panel lengths. under-capacity winches In strike gullies. and excessively long strike scraping distances.

Jan 12, 1975

In many practical situations, calculation of the point semivariogram is not necessary. Such a case is analysed in this chapter. The purpose of this analysis is to give a better understanding of the meaning of the mathematical formulae developed in the previous chapters. A similar problem will be studied in Chapter 11, using the point semivariogram.

Jan 1, 1978

Messrs B. R. Braekman and D. W. Penman have notified some errors in the Addendum that was attached to their paper, 'The Prieska experience: Flotation developments in copper-zinc separation', which was published in the August issue of this Journal (vol. 91, no. 8, pp. 264-265).

Jan 1, 1991