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The imbalance between the coal resources contained in thin seams (1,5 m or less) and the production from them is outlined. It is suggested that an Increase In the exploitation of thin coal seams is necessary, and that drum-type continuous miners can produce a substantial amount of any increase. Continuous miners are employed in a number of mining methods including bord-and-pillar, pillar extraction (stooping), rib-pillar extraction, and shortwalling. These techniques of mining are evaluated with respect to production rates and the cost of extraction for South African conditions included in these evaluations are the types of equipment used to transport coal from the mining machine to the section conveyor belt. Computer simulation techniques are used to generate the required production levels, and interpretations are made of other results from the computer modelling. For thin, coal seams, bord-and-pillar mining utilizing continuous haulage is apparently the most productive and cost-effective of all the methods using the continuous miner. The relative efficiencies of the other techniques of mining and of coal-transportation vehicles are also outlined.

Jan 1, 1984

By H. S. Eisner, J. -P. Leger

Published South African fatality and injury statistics for mine accidents are investigated. Where possible, the South African statistics are compared with those of other countries. Commonly held attitudes to the South African accident experience are also examined. Analysis reveals that the published accident rates present a more favourable picture than the rates actually experienced by underground workers. In addition, fatality rates in South African underground gold and coal mines do not differ significantly and have remained stable over the past decade, although the injury rates have decreased rapidly. No evidence was found that this is due to improved safety, and a comparison with international fatality and injury data suggests that it is not. The underground fatality rate for South African coal mining is, on average, eight times that of the UK, four times that of all EEC coal mines taken together, and over double that of the USA. Despite the unreliability of the injury rates, much has been made in South Africa of their rapid decline, an emphasis that appears to be misplaced.

Jan 1, 1988

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 D. D. Howat, J. van der Colf

This paper is the first in a series of three dealing with this subject and also with the rate of oxygen removal from the slags in the presence of solid carbon and with the physicochemical properties of the reduced slags. For selected members of the system, the melting temperatures and primary crystallization products were determined. as were the viscosity and the electrical resistivity of the corresponding melts. All the experiments were conducted in a neutral atmosphere. Where determined, the primary phase was found to be either perovskite or magnesium aluminium titanate. The composition variable exerting the most pronounced influence on viscosity or resistivity was found to be the basicity expressed as the mass ratio (CaO + MgO)jSiO,. The ratio CaOjMgO became important only at Iow basi<:ity values. Although generally there is a direct proportionality between log (viscosity) and log (resistivity), slags h&apos;lving either a very high silica content or a very high titania content have anomalously Iow electrical resistance.

Jan 1, 1979

By A. Mainza

It is common practice in the mineral processing industry to use hydrocyclones for particle classification. However, classification in the UG2 platinum circuits using the hydrocyclone poses major challenges due to the differences in density between silica and chromite, the two major components of this ore. Silica,-the PGM carrying component, has an average density of 2.7 and the barren chromite component has an average density of 4.5. When conventional and flat bottom cyclone are used there is a misplacement of particles due to differences in density leading to inefficiencies in the classification by size. As a result of the density effect, coarse silica reports to the overflow, resulting in loss of recovery, and fine chromite reports to the underflow, resulting in loss of milling capacity and unnecessary production of fine chromite. A classifier based on a different concept was required in the classification of UG2platinum ore. The three-product cyclone, which is a hydrocyclone with two concentric vortex finders to produce three distinct products, has been tested in the UG2 ore application and indications are that misplacement of particles due to differences in the component densities can be minimized through the use of this unit. Industrial and pilot plant trials were conducted and indications are that the three-product cyclone can be installed to selectively produce a middlings stream that can be screened using Pansep screens to provide a screen oversize, which is predominantly coarse silica that can be preferentially reground to recover the PGM values contained in the coarse silica.

Jan 1, 2004

By E. Uslu

The kinetics of the reduction of chromite from the LG-6 layer of the Bushveld Complex in Fe-Cr-C alloys were studied in the temperature range 15OO°C to 1680°C under an inert argon atmosphere. The rotating cylinder technique was used, and the rotational speed of the chromite cylinder ranged from 0 to 1000 r/min. The melt consisted of 30 to 80 per cent chromium and 2 to 8 per cent carbon. The initial chromium-te-iron ratios of the melts varied between 0,42 and 4,95. The reduction of chromite spinel was analysed in terms of the decarburization of the metal. It was found that decarburization increased with an increase in the temperature, the carbon content of the bath, and the rotational speed of the cylinder up to 400 r/min, after which it remained almost constant. Decarburization also increased with an increase in the chromium content up to about 50 per cent chromium but, at higher chromium contents, it decreased. In the early stage of the reduction, up to about 30 minutes of reaction time, the liquid-state mass transfer of oxygen was found to be the most likely rate-determining step. The apparent activation energy was calculated to be 84,864 kJ per mole of oxygen. In the later stage, diffusion of iron and/or chromium in the solid state is the most likely rate-determining step. The apparent activation energy for the diffusion was calculated to be 471,18 kJ/mol.

Jan 1, 1991

1. Book reviews Tungsten: 1982. London, Mining Journal Books Ltd, 1982. 179 pp. Reviewer: G.A. Brown The geology of industrial minerals in Canada, edited by G.R. Guillet and Wendy Martin. Canadian Institute of Mining and Metallurgy, special volume 29. Reviewer: R.W.O. Kersten Foam flotation - theory and applications, by Ann N. Clarke and David J. Wilson. New York, Marcel Dekker, 1984. 418 pp. Reviewer: B.K. Loveday Industrial and financial indicators of the steel industry, by Patrick Genevaz. Paris, La Chambre des Cartes, 1982. 2 vols. Vol I: Analysis and conclusions, FF3500. Vol. 11: Tables, FF4000. Reviewer: R.J. Dippenaar An encyclopaedia of metallurgy and materials, by C.R. Tottle. Plymouth, Macdonald and Evans and The Metals Society, 1984. 481 pp. RI44,50. Reviewer: P. T. Wedepohl The role of crack growth in metal fatigue, by LP. Pook. London, The Metals Society. Reviewer: C.A. Boothroyd Hydraulic coalmining - new technology and its geological and industrial significance, by H.C. Siebert. Hamm, Zentraldruckerei BAG, 1984. 33 pp. Hydraulic coalmining - hydromining update: potential impact on coal deposits and coal mining industry, by H.C. Siebert. Hamm, Zentraldruckerei BAG, 1984. 130 pp. Victoria&apos;s brown coal. A huge fortune in chancery, edited by J .T. Woodcock. The Australasian Institute of Mining and Metallurgy, 1984. 204 pp. Reviewer: J.J. Versluis 2. Canadian publications The following reviews of the activity and developments during 1982 in respect to the chief minerals produced or consumed in Canada are now available. Zirconium. An important mineral commodity. Mineral Policy Sector, Mineral Bulletin MR 202, $6.60. Canadian minerals yearbook 1982. Mineral Policy Sector, Mineral Report 32, $40.75. Canadian reserves of copper, nickel lead, zinc, molybdenum, silver and gold as of January 1, 1983, by W.H. Laughin. $4.20. Mineral Policy Sector, Mineral Bulletin MR 201. Sulphur market profile, by B.W. Boyd. Mineral Policy Sector, MRI 84/5. 3. Mintek publications Report M123 The use of of activated charcoal in a NIMCIX column for the recovery of gold from cyanide solutions. Report M150 Energy transfer in the hearths of submerged-arc furnaces. Report M151 A preliminary investigation of the initiation of pitting corrosion in austenitic stainless steels and nickel-based alloys. Report M154 The reduction of Winterveld chrome spinel at 1300°C under an argon atmosphere in the presence of carbon. Report M165 The development of an improved on-line gold analyser. Report MI67 three nebulizers for use with an inductively coupled plasma spectrometer. 4. New publications Mineral Industry Consultants Association (as at 31st March, 1984). Parkville (Australia), The Australasian Institute of Mining and Metallurgy, 1984. 112 pp. Philosophical and procedural guidelines for the planning professions. Johannesburg, the Environmental Planning Professions Interdisciplinary Committee (EPPIC, P.O. Box 61019, Marshalltown 2107), R2.50. Directiona//y solidified materials for high temperature service, by M. McLean. London, the Metals Society, 1983. 337 pp. Tin and its uses no. 142. Greenford (England), International Tin Research Institute, 1984. Metals engineering International Symposia & Exhibitions Ltd - a subsidiary of Industrial Newspapers PLC - are pleased to announce that they will be organizing a mammoth engineering event, entitled Metals Engineering 86, comprising five important exhibitions in 1986:. Agglomeration A major symposium on agglomeration is being organized in Toronto for the 2nd to 5th of June, 1985. Speakers from around the world (Canada, U.S.A., Brazil, Australia, Japan, West Germany, Italy, India, China, Switzerland, Poland, Yugoslavia, and France) will address delegates on various aspects of agglomeration relative to iron ore, coal, coke, and fuels. Plenary theme papers will also be presented by speakers from Japan, the U.K., and the Netherlands.

Jan 1, 1985

By M. Steyn

Until 2000, pricing involved profit taking and cost covering combined with limited global published information. Market information was mostly subjective in nature and large resource companies benefited exclusively from aggregated company information and data. The market constituted producers and consumers only. The nineties saw massive cost cutting drives and re-engineering initiatives and this underwrote the structural changes evident in the late 1990s? economy. This supported South African producers on the international FOB cash cost curve, and ensured profitable coal mining operations. As the debate on relative scarcity of fossil fuels ensued, producers and buyers looked to the developing terminal coal market for direction. The much needed direction was provided when the API coal indices were developed and derivative trading was embraced to include financial institutions, trading houses and hedge funds. The liquidity of coal trades increased rapidly and vastly and market information became obtainable on a daily basis. Interpretation of current and future coal prices became available to all market players and contributed to the sophistication of the market that is now able to participate in risk management of prices, capital expenditure and brownfield developments.

Jan 1, 2010

By U. C. Galimidi, J. M. Stewart, A. J. Van Rensburg

The effect of body movement on convective heat transfer from a man performing a block-stepping task was investigated experimentally by direct measurements of convective heat transfer. A series of experiments was conducted in which a nude man was required to stand at rest or to block step at 12 and 24 steps per minute. Wind speed, which was kept constant during each experiment, spanned the range 0,5 to 3,5 m/so Air temperature was kept constant at 43 °C in all the experiments. The results showed conclusively that the convective heat-transfer coefficient depends on the stepping rate. The effect of body motion can be regarded as being equivalent to an increase in the velocity of the free stream. The equivalent increase in air speed was found to be 0,36 and 0,77 m/s for 12 and 24 steps per minute respectively. Data from various sources, including the present study, indicate that wind speed should be increased by about 0,30,0,55, and 0,80 m/s to account for low, moderate, and vigorous body movements respectively. These findings are of direct relevance to the practical assessment of heat stress.

Jan 1, 1979

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

The mathematical models of semivariograms can be classified according to whether or not they correspond to situations where the second order stationarity conditions are satisfied (§ 3.3.4). If second order stationarity exists, the a priori variance s2 of x (z) also exists and is finite. For large distances h such that x (z) and x (z + h) are not correlated, the semi- variogram ? (h) will reach a value equal to s2 [this is a consequence of (3.27) above]. This limiting value is called the sill C of the semivariogram, and the distance at which ? (h) reaches the sill is called the range. The range of the semi- variogram obtained from a given type of sample corresponds to the distance of influence of these samples. If only the intrinsic hypothesis is satisfied, the sample variance is an increasing function of the size of the area or volume in which the samples are located, and the semivariogram ? (h) will be a continuously increasing function of h. Remark: It will be shown in Chapter 7 that the variance s2 of x (z) in the ore body O is equal to the average value of ? (h) in O. If ? (h) is a non-decreasing function with sill C, the average value of ? (h) in O will be less than C. s2 and C will be equal only if for some values of h in O, ? (h) exceeds C. In practice, if the range of the semivariogram is small with respect to the dimensions of the ore body, the difference between C and s2 will be negligible.

Jan 1, 1978

Branch Minutes of the General Meeting held at President Steyn Gold Mine canteen on Wednesday, 10th May, 1978, at 4.00 p.m. Erratum We apologize to Mr J. G. Taylor for the error in one of his qualifications. Bio-engineering monograph The selection of papers presented at the International Bio-engineering Conference at the University of Cape Town organized by the South African Institution of Mechanical Engineers and held in April 1977, and which are appearing in The South African Mechanic al Engineer during April to June this year, will shortly be available in book form. Mathematics The Institute of Mathematics and Its Applications is planning the following conferences and symposia: The Nand F Proposals in Relation to Mathematics, 1st July, 1978: London School of Pharmacy. NIM reports Report no. 1917 The instrumental neutron-activation analysis of granites from the Bushveld Complex. (31st Mar., 1978.) Report no. 1951 Potentialities and limitations of four-parameter equations for the correlation of formation constants of metal-ion complexes in aqueous solution.(15th May, 1978.) Report no. 1963 An evaluation of the methods used at the National Institute for Metallurgy for the analysis of base-metal concentrates. (28th Apr., 1978.) Report no. 1964 The separation, by anion exchange, of noble metals on substituted cellulose. (28th Apr., 1978.) Guide To The Preparation Of Papers For Publication In The Journal Of The South African Institute Of Mining And Metallurgy 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.

Jan 1, 1978

To the members of The South African Institute of Mining and Metallurgy We have audited the annual financial statements set out on pages 272 to 277. These financial statements are the responsibility of the Institute&apos;s Council. Our responsibility is to report on these financial statements. We have conducted our audit in accordance with generally accepted auditing standards. These standards require that we plan and perform the audit to obtain reasonable assurance that, in all material respects, fair presentation is achieved in the financial statements. The audit included an evaluation of the appropriateness of the accounting policies, an examination, on a test basis, of evidence that supports the amounts and disclosures included in the financial statements, an assessment of the reasonableness of significant estimates, and a consideration of the appropri¬ateness of the overall financial statement presentation. We consider that our auditing procedures were appropriate in the circumstances to enable us to express our opinion presented here. In our opinion these financial statements fairly present the financial position of the Institute at 30th June, 1996, and the results of its operations for the year then ended in conformity with generally accepted accounting practice.

Jan 1, 1996

Report of the independent auditors To the members of The South African Institute of Mining and Metallurgy We have audited the annual financial statements set out on pages 251 to 257. These financial statements are the responsibility of the institute&apos;s Council. Our responsibility is to report on these financial statements. We have conducted our audit in accordance with generally accepted auditing standards. These standards require that we plan and perform the audit to obtain reasonable assurance that, in all material respects, fair presentation is achieved in the financial statements. The audit included an evaluation of the appropriateness of the accounting policies, an examination, on a test basis, of evidence that supports the amounts and disclosures included in the financial statements, an assessment of the reasonableness of significant estimates, and a consideration of the appropri¬ateness of the overall financial statement presentation. We consider that our auditing procedures were appropriate in the circumstances to enable us to express our opinion presented here. In our opinion these financial statements fairly present the financial position of the institute at 30th June, 1998, and the results of its operations for the year then ended in conformity with generally accepted accounting practice.

Jan 1, 1985

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), &apos;Foundations&apos;, 1973. The editors of Foundations, Australia&apos;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 &apos;releasing agents.

Jan 10, 1973

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

To the members of The South African Institute of Mining and Metallurgy We have audited the annual financial statements set out on pages 251 to 257. These financial statements are the responsibility of the institute&apos;s Council. Our responsibility is to report on these financial statements. We have conducted our audit in accordance with generally accepted auditing standards. These standards require that we plan and perform the audit to obtain reasonable assurance that, in all material respects, fair presentation is achieved in the financial statements. The audit included an evaluation of the appropriateness of the accounting policies, an examination, on a test basis, of evidence that supports the amounts and disclosures included in the financial statements, an assessment of the reasonableness of significant estimates, and a consideration of the appropri¬ateness of the overall financial statement presentation. We consider that our auditing procedures were appropriate in the circumstances to enable us to express our opinion presented here. In our opinion these financial statements fairly present the financial position of the institute at 30th June, 1998, and the results of its operations for the year then ended in conformity with generally accepted accounting practice.

Jan 1, 1998

By S. J. Patchet

The use of fill in deep-level gold mining presents the possibility of achieving considerable economic and operational benefits if conventional support can be eliminated. Unfortunately, the combination of the properties of tailings from gold reduction plants and the narrow, flat, tabular reefs being exploited make conventional hydraulic filling very unpractical. Laboratory tests indicate that, with careful control of water content, these tailings can provide an adequate fill material. A variety of bonding agents have been investigated, and the most practical seems to be ordinary Portland cement. Even at very low cement contents some cohesion is achieved. The design and layout for a complete fill support system using hydraulic transport, dewatering, and pneumatic placement are discussed, and a surface field trial indicated that the principles involved are correct and that acceptable results can be achieved. This system and material would completely eliminate conventional timber and brick support, and a preliminary economic analysis indicates that filling is cost competitive on a direct replacement basis. All the operations for a full-scale operation are available or have been developed to a stage sufficient to indicate that the system is practical, although certain operations require further refinement.

Jan 1, 1978

By A. Koning

Pressure hydrometallurgy operations require vessels to be lined with an impermeable membrane for corrosion protection and one or more courses of refractory or ceramic brick. Examples of unit operations that utilize composite lining systems include pressure oxidation autoclaves, sulphide precipitation autoclaves, chloride leach reactors, flash vessels, cyclone separators, and direct contact condensers (heater vessels and quench vessels). The refractory lining must satisfy multiple requirements: it must thermally insulate the membrane from process fluid, be structurally stable, provide erosion resistance, be chemically compatible with process fluid, and provide an economic service life. New hydrometallurgical processes are pushing the pressure, and temperature with each new generation of plants. A fundamental understanding of all factors affecting the mechanical stability of the lining system is essential as lining designs move further away from the industry?s experience base. The method of designing a refractory lined vessel is examined taking into account the impact of irreversible chemical swell, operating factors, design factors, and installation factors. The effect of geometry and incorporating additional degrees of freedom to the analysis is explored using two-dimensional and three-dimensional finite element analysis (FEA). The effect of these additional degrees of freedom on the results of the one-dimensional model are discussed. Keywords refractory lining design,autoclave, finite element analysis.

Aug 1, 2013