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By I. M. MacGregor

This paper discusses the possible use of petrological data and proximate analyses in the prediction of cutting forces for coal. It is restricted to the development of univariate predictors based on data from thirteen collieries in five major Transvaal and Orange Free State coalfields and three coal provinces. The aim of the work was the identification and development of the best predictors of mean peak cutting force and Hardgrove grindability index from among the independent variables evaluated. The data, which were obtained by use of the penetrometer developed by the Chamber of Mines Research Organization, were processed according to the SPSS computer package. The analysis revealed reasonable correlations between the Hardgrove grindability index and (1) the volatiles and vitrinite content in the Vereeniging-Sasolburg and South Rand Coalfields, (2) the contents of vitrinite, vitrinite plus exinite, and minerals plus inertinite in the Eastern Transvaal Coalfield.

Jan 1, 1985

Dr H. J. van Eck (Honorary Life Member): "Mr President, I regard it as a signal honour that I was invited to address the South African Institute of Mining and Metallurgy on its 75th Anniversary. I also wish to add my congratulations and good wishes to the many you have already received on this memorable occasion. Seventy-five years is indeed a good age and the achievements of your Institute certainly justify this special celebration. South Africa owes her present prosperity largely to the technological ability and determination of her own people. Members of the Institute contributed in large measure to this great development of our country and through the years have upheld their high reputation for scientific integrity, dynamic enterprise and dedicated service. It was their knowledge which provided the key to unlocking the mineral wealth which lay dormant for countless ages. The history of world mining dates back many centuries. We know of the mercury mines of Spain, the tin mines of Cornwall and the zinc mines of Poland, but it was not until colonization of the western hemisphere started in about 1500 that mining of any consequence began in North America. It is true that the peoples of South America and Mexico had accumulated wealth out of gold and silver, but industrialized mining was not a feature of these agrarian cultures. The mining wealth that eventually developed in North America was based on advances in the technology of processing minerals and served as an incentive to people in other new countries. Big mines were opened elsewhere in the world. From Canada, Mexico, Venezuela, Brazil, Peru, Chile, Bolivia, Rhodesia, Australia, Burma and India, to name but a few, there has been a steadily increasing production of an expanding range of minerals and metals. By the middle of the 20th century the trend was to increase the production and use of such comparatively uncommon metals as cobalt, nickel, titanium, and others, and a great mining rush started to search for, and develop, the deposits of uranium, and related radio-active minerals. It is worth pausing a few minutes to reflect that most of early mining was based on the recovery of virgin metals like gold and silver or easily treated high grade ores of copper, tin and zinc. Today, much of this type of mining would be regarded as picking the eyes out of the mine. With the development of improved ore separating, ore concentration and recovery processes, we developed into bulk mining and bulk treatment and in South Africa we have some very big mines, also outside the gold mining industry at Phalaborwa, for instance. Mining techniques are applied which compare with the best in the world. These large mines could only develop because of the perfection of new concentrating techniques and, of course, because of the development of markets. We have mentioned nickel and cobalt. These names were given to those mischievous mining sprites called nickels and kobolds to whom the suspicious miners ascribed their inability to smelt copper from copper nickel or arsenious copper ores. In South Africa, the presence of minerals was known to the modern Western world as far back as 1497 when Vasco da Gama found the native 'strandlopers' at the St. Helena Bay wearing copper rings. In 1669, after the British East India Company had formed their settlement, they employed miners and assayers in prospecting for minerals and in 1685 found traces of copper in the copper mountain of Namaqualand where some 170 years later a rich deposit of copper was to be opened up. This deposit also had a chequered

By R. Degel

Submerged arc furnaces and electric smelters are applied in numerous metal and slag production lines. Particularly in ferroalloy and non-ferrous metal production, like silicon metal, platinum group metals, calcium carbide, and copper, the units are an essential part of the production technology. Most of these electric furnaces are considered to be highly energy-intensive units. The high level of required electrical power is defined by the process. SMS developed several measures to reduce the overall electrical energy consumption of these metal production lines. In particular, the following measures contributes to a lower energy consumption: improved electrical efficiency with intelligent design and application of components, minimizing the heat losses from the furnaces with a balanced cooling/refractory systems, minimization of process steps (such as elimination of agglomeration), recovery of energy, process optimization (resulting in higher metal yield) and the achievement of higher recovery rates, enlarging furnace capacity to reduce heat losses, and maximizing the power-on time. This paper gives an overview of the above-mentioned solutions.

Jan 1, 2012

By HORNICKA OSTRAVA

The Czechoslovak Scientific-Technical Institute has arranged the international conference 'Hornicka Ostrava' for four or five days at the end of October, 1969, as part of the preparation for the international 'Miners' Congress' on deep coalextraction in 1970. The keynote of the conference is 'New Techniques in coal mining,' and will be covered by five groups dealing mainly with: 1. New trends in the opening of mines, optimal parameters, projections, equipment, utilization of computers for economic analyses, etc. 2. Increase in efficiency of coal extraction in deep mines, technology, concentration, pressure control, optimization of material and coal transport. 3. Modernization of devices for increased safety and working conditions, new trends in explosives, new techniques for reducing environmental diseases. 4. Innovations in deep level coal extraction, mechanization, rationalization, automation, etc. 5. Other topics about modern techniques in mining. Address your enquiries to: Ing. Karel Kalas (Secretary of the Conference), Dum Techniky Cs YTS, Ostrava 1, Jesenkiho 7-9, Czechoslovakia.

By N. B. Strydom

The data on heat stroke cases reported during the past five years were examined to determine the influence of age on the incidence of heat stroke. Relating the age distribution of these cases to that of the total number of Bantu mine workers showed clearly that the older men run a significantly higher risk of developing heat stroke than the younger men. Although the number of Bantu over 40 years of age in the industry is less than 10 per cent of the total they nevertheless accounted for 50 per cent of the fatal heat stroke and 25 per cent of the nonfatal heat stroke cases during the period under review. Age must, therefore, be recognised as a causal factor in heat stroke and the worker over 40 years of age should be allocated to work on surface, or in cool areas or to non-strenuous and supervisory tasks in hot areas.

By C. G. Hutson

The Zinc Corporation of South Africa (Zincor) were hosts to about forty members of the Institute at their works in Springs on Friday, 25th April, 1986. The programme, designed to give an overview of the industry and the part played by Zincor, comprised an introductory talk, a technical talk, a tour of the plant, and a luncheon. Radioactive waste in arid regions A conference on the disposal of radioactive waste in arid areas will be held in Cape Town during the period 7th to 12th September, 1986. It is recommended that engineers and scientists avail themselves of the opportunity to familiarize themselves with this relatively new multidisciplinary field of endeavor by attending the first ever conference of this nature to be held in South Africa. Iron control in hydro metallurgy The International Symposium on Iron Control in Hydrometalurgy will be held at the 16th Hydrometallurgical Meeting, from 19th to 22nd October, 1986, in Toronto, Canada.

Jan 1, 1986

By R. Meyjes, P. Davies

Keywords: Pyrometallurgy, furnace, smelter, engineering company Metix is a private smelter engineering company wholly owned by its management. Its main lines of business in the ferro-alloy industry being: - turnkey smelter projects (LSTK) - engineering, project, and construction management projects (EPCM) - specialised furnace equipment comprising: ? complete electrode columns, including forged copper pressure rings and contact shoes, as well as fail-safe slipping devices ? water-cooled roofs ? bus-tube systems ? feed systems ? cooling systems ? linings ? off-gas systems ? tap-hole drills & clay guns - furnace power supply systems - ore agglomeration & sinter plants - feasibility studies & due diligence reports - technical consulting for investment banks - project procurement & cost control Metix management experience includes around 130 combined years of contacts and experience in the South African smelter industries. Over 30 furnaces have been built, for processes including FeCr (high, medium, and low carbon), FeSi, FeMn (high and medium carbon), SiMn (ultra low carbon), Si metal, and FeV.

Jan 1, 2006

Infacon 74 The National Institute for Metallurgy, the South African Institute of Mining and Metallurgy, and the Ferro-Alloy Producers' Association of South Africa extend a cordial invitation to participate in the International Ferro-alloys Congress to be held in Johannesburg, South Africa, in April 1974. Obituary RICHARD AUSTIN COOPER On the 31st March 1972, a once very active member of the Institute, R. A. Cooper, died at the age of 82. He had served on the Council for many years and was Vice-President in 1933/34. ALEXANDER JEREMIAH ORENSTEIN CB., CM.G., C.B.E., LLD., D.Se., M.D., M.R.C.S., F.R.CP., F.R.S.H. Dr Orenstein, who died on the 7th July 1972 at the age of 92, was so well known and so widely acclaimed during his lifetime that it is difficult to add to the tributes which have already been paid to him.

By D. G. Krige

The scope and salient features of a general risk-analysis model for the main types of new mining ventures are covered in brief outline. The following special features and their effects on the investment criteria are discussed: - various criteria for viability, - the maximum shortfall of funds, - correlations between the grades of up to five ore constituents and between the corresponding product prices. differential inflation and escalation rates for costs and prices, - the estimation, if relevant, of a pay limit based either on the major product only, or on the two major products jointly, - the likely recovery grades of all the products to be obtained when the ore-body is mined to any such pay limit. - an option to take account of the effect on the pay limit of any negative taxation on marginal ore, - investment analyses in current and real terms for individual groups of investors subscribing for equity and any loan capital on differential terms.

Jan 1, 1979

By M. J. Gouws, T. P. Knoetze

The spontaneous combustion of coal and the explosion of coal dust are two phenomena that were identified by the South African mining industry as requiring investigation. Research contracts were awarded to the G.P. Badenhorst Research Facility of the CSIR and the Department of Mining Engineering of the university of the Witwatersrand by the now defunct National Energy Council. Both projects entailed tests on numerous coal samples in specially designed apparatus. Since the completion of the project, attempts have been made to predict experimental results without incurring the cost of performing experiments. This paper describes predictive indices, based on routine laboratory tests, that were developed by the different research teams for their particular projects. A comparison of the results obtained by applying the spontaneous combustion liability index and the explosibility index to common coal samples indicates that, in general, propensity to spontaneous combustion and explosibility exhibit an inverse relationship. A brief overview is given of some major South African coal-mine disasters.

Jan 1, 1995

A Special General Meeting of The South African Institute of Mining and Metallurgy was held at Kelvin House, Johannesburg, on Wednesday, 20th August, 1986. Mr H.E. James (President) was in the chair and declared the meeting open at 15h45. Background The Chairman explained that the meeting had been called to consider a number of amendments to the SAIMM constitution. The proposed changes had been set out in detail in a document that had been mailed to all members on 4th July, 1986. He then briefly reviewed the background to the proposals, which is outlined in the Preface to the Annual Report (page 357 of this issue). The Chairman added that the Executive Committee of SACPE at its meeting on the 8th August, 1986, had resolved that the proposed amendments to the SAIMM constitution did comply with the requirements of Regulation RI525 dated 17th July, 1981, regarding the recognition by SACPE of a society as a Professional Engineering Institute.

Jan 1, 1986

By H. E. Parkinson, Y. P. Chugh

About 90 percent of the coal mined underground in the U.S.A. today is mined by the room-and-pillar system. The productivity of the system dropped from about 14,1t per man-day in 1969 to about 7,3 t per man-day in 1978. Since 1974, the U.S. Department of Energy (formerly the U.S. Bureau of Mines) has been engaged in research to improve the production and productivity of the room-and-pillar system. The effort involves the development of integrated, automated, and remote-controlled equipment and systems including remote-controlled continuous miners, automated miner-bolters, automated extraction systems, continuous haulage systems for use behind miners, and remote-controlled equipment for miners, bolters, and shuttle cars. These systems are discussed briefly, the discussion being related primarily to coal winning, although the concepts could be utilized in room-and-pillar systems in mines other than coal mines.

Jan 1, 1981

By J. C. Zachariades, D. M. Fraser

The leaching of pyrolusite in acidic ferous sulphate solution was studied so that the important factors governing the kinetics of the reaction could be determined. The reaction is very rapid, and was monitored by continuous measurement and logging of the redox potential in solution by use of a microcomputer. The relationship between redox potential and manganese extraction was established empiricaly for each set of conditions by the use of a technique in which a calibration run was conducted in paralel with each leaching run. The study involved a number of batch leaching runs, and demonstrated that, of the variables investigated, only the initial ferous ion concentration and the reaction temperature afect the rate of manganese extraction. The final extraction did not vary. The reaction was modeled from the results by use of the shrinking-core model and Britan's activation-energy model. The later was found to provide a significantly better fit to the data.

Jan 1, 1991

By J. H. Bulloch

The paper gives an assessment of the available data on the linear elastic fracture mechanics involved in stress corrosion cracking and in the behaviour of reactor pressure-vessel materials exposed to a simulated pressurized water-reactor environment. As a result of the different experimental techniques used in the various studies mentioned, only a few detailed conclusions can be drawn. The data from constant-displacement wedge-opening loading (WOL) tests, with the exception of one study, exhibited very limited or no crack extension during exposure periods of up to 14000 hours. The data from constant-load tests indicated evidence of crack extension, but the nature and extent of the crack extension are still unclear. When crack extension did occur, it was exclusively transgranular in nature. Certain differences in the available test data are tentatively explained in terms of the experimental procedures used, and the need for a consistent code of experimental techniques is highlighted.

Jan 1, 1987

By W. A. Lenhardt

During the past five years, several research projects on the causes of mining induced seismicity have been carried out by the Rockburst Research Department at Western Deep levels Limited. This paper summarizes the results of these investigations. Several types of mining-induced seismic events are addressed, and models of their mechanisms are presented. It is shown that most of the seismicity results from mining in geologically disturbed areas, and ways and means are discussed to reduce the seismic potential. Stabilizing pillars, for instance, have been introduced to reduce stresses at the stope face and to alleviate the facebursting problem. Facebursts still occur in areas of very low stresses, and pillars became the source of very large seismic events (M >3). At this stage, the understanding gained of pillar-associated events allows a review of current mining practices. Further, it makes possible an examination of the efficiency of measures to alleviate the effects of various seismically prone situations.

Jan 1, 1992

By Siemag Transplan GmbH

At the Hansa Mine in Dortmund, Germany, coarse run-of-mine coal, up to 60 mm in particle size, has been brought to the surface hydraulically from a depth of 850 m since November 1977. Hoisting is done by a three-chamber pipefeeder, by means of which up to 400 t/h can be lifted. The pipefeeder operates without problems, and has so far shown itself to be efficient and reliable. Vertical hoisting can be carried out by water supplied from the surface, from underground, or from a surface water supply in combination with minewater from underground. Water that flows into the mine, which would in any event have to be pumped to the surface, can be utilized for hoisting operations. The energy costs per ton of coal for a lifting height of 850 m vary between 41 and 62 South African cents, and therefore lie within the range of costs that apply to conventional hoisting.

Jan 1, 1980

By J. Zwartendyk, A. Azis

Optimizing the public gains from the exploitation of mineral resources By Dr A. AZIS and Dr J. ZWARTENDYK Every nation must decide how it should exploit its mineral resources so as to contribute most to its national objectives. It is argued that the present value of the future corporate income tax flow derived.from mineral exploitation may serve as a useful indicator in moving toward a taxation policy that would contribute optimally toward the greatest public benefit. The future stream of corporate income taxes depends largely on the mineral endowment, consisting of deposits now being mined, known unmined deposits, and unknown deposits. Unknown deposits may be estimated by geological inference. Both known and unknown deposits can be categorized according to grade and size, and divided into economic and uneconomic deposits on the basis of certain prices, costs, rate of return and taxation levels. Computer simulations can be run of discounted cash flow models at various taxation levels to showthe impact of taxation changes on future tax revenues.

By Nareetsile S., J. Kabwe

In the past few years Orapa and Letlhakane Mines have investigated various new technologies to enhance and improve production. The goal has been to improve productivity, reduce operating costs and make the mines more profitable The advent of Global Positioning Systems (GPS) in the early ’80s brought about the realization of this concept. Orapa and Letlhakane Mines started using GPS in 1999 and it is now used atLetlhakane mine for surveying, vehicle tracking and dispatching and for floor control system. Orapa Mine uses GPS in surveying, floor control and drill navigation. It will also be used for vehicle tracking and dispatching in mid-2001 following the installation of a fleet management and control system. The introduction of GPS at both Orapa and Letlhakane mines have improved productivity and reduced operating costs in the areas of drilling, topographic survey and floor control. In vehicle tracking and dispatching GPS has allowed for real-time information management for timeous decision-making which optimized fleet run time hours.

Sep 1, 2001

By K. G. Lomberg

The integration of various highly sophisticated IT applications has been implemented at Bafokeng Rasimone Platinum Mine, a new platinum mine in the Anglo Platinum Group. This system is required to assist with compiling the necessary geological and grade information together with safety, environmental, ventilation, rock engineering and logistical constraints, to allow the design of the appropriate mining layout, to schedule this design, provide the necessary output for technical review and costing as well as budgeting to allow medium- and long-term business planning. In addition the production management and short-term planning needs must be met. This includes the plotting of all underground and surface infrastructure and excavations, giving the necessary mining and best cut instructions, daily production management, ore reserve and grade management as well as assisting with budgetary management. In addition all safety, health, environment and risk assessment requirements and legal requirements have to be met. The system at Bafokeng Rasimone Platinum Mine has met these criteria. Keywords: Platinum, Bushveld Complex, Mine Planning, Production Management

Jan 1, 2003

Contribution by W.D. Ortlepp In the Journal of May 1994, the authors first presented the concept and analysis that formed the basis for a design approach for deep tunnels, now expressed more explicitly in the present paper (March/April 1996). In a contribution in the Journal of March/April 1995, I expressed a certain disquiet about the validity of their original approach. The authors responded to these criticisms in the same issue. It is apparent to me now that both the contribution and its rebuttals were written, probably for different reasons, in such an obscure and pedantic way as to further confuse the reader rather than provide enlightenment. My concern still persists. But in order to avoid further confusion I will attempt to pose my uncertainties and difficulties in a much more direct way. On page 98 (top of 2nd column) in the earlier paper, an important statement concluded as follows: '. . . the horizontal ellipse requires 140 per cent less force for equivalent stability'.

Jan 1, 1996