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By M. H. Moys, K. S. Liddell

The dynamics of the ball load within a wet-grinding mil are examined, using measurements of torque and load position, The test equipment provided an accurate torque measurement, and the toe and shoulder positions of the load were measured by the use of a conductivity probe mounted in the mill shell. Both the variables tested-mil filing and rotational speed-influence the position of the load, and hence the torque, and have interactive effects on both the torque and the load position, An increase in mil speed and filing causes the torque to increase to a maximum value, after which further increases in speed or filing cause the torque to decrease. The position of the load toe is influenced only by the filing up to speeds of approximately 80 per cent of critical, whereas the speed and filing both cause the load shoulder to rise as their magnitudes are increased, The power drawn by the mill is predicted by the use of published equations, and these values are compared with the measured power draw.

Jan 1, 1988

By R. G. Jurd

This paper considers the introduction of large-scale longwall mining into South African coal mining, instead of the conventional mechanized bord-and-plllar mining that is widely practised at present. The two methods are compared, and longwall mining is found to have the advantage in several respects in some seams. The most cogent reasons for the introduction of the longwall method In some seams are associated with safety strata control and increased labour costs.

Jan 1, 1978

By H. A. D. Kirsten

The effects of the mining of deep-level tabular reefs are usually evaluated by use of continuum, elastic mining simulation analyses. This paper gives the results obtained from a series of analyses in which stopes of limited span are considered to be excavated in a non-linearly non-elastic, jointed and fractured rockmass. In particular, the theoretical influence of soft backfill in these conditions is evaluated. It is shown that the stress distribution and behaviour of the rockmass, alternately taken as an intact-elastic and as a fractured non-elastic medium, are completely different. The relevance of the energy-release rate commonly calculated in mining-simulation analyses, and the efficacy of its correlation with seismicity and the associated rockbursts, are reviewed. In deep-level mining operations, it is not practically feasible to obviate releases of seismic energy. The fact of their occurrence should therefore be accepted and, rather than considering the reduction of energy release as the primary objective, efforts should be concentrated on minimizing the effects of such release. Analytical results are given to demonstrate that this approach is not only correct, but also the only feasible solution to the rockburst-seismicity problem in deep mines.

Jan 1, 1989

By D. G. Krige

Some basic considerations in the application of geostatistics to the valuation of ore in South African gold mines by D. G. KRIGE, Pr. Eng., D.Se. (Eng.) Rand (Fellow) There is much room for improvement in the statistical procedures that have been used by gold mines over the past decade in the valuation of their ore reserves. Improvement depends on the establishment of the extent to which the patterns of frequency distributions and the directional variograms for the gold values vary from area to area within each section of a mine. The application of the lognormal distribution and of the De Wijsian variogram model for routine ore-reserve valuations requires detailed study before some of the reservations still held by mathematical statisticians can be met. This paper provides some preliminary evidence of the extent to which these models can be used with confidence, as well as suggesting how they can be applied to their full potential.

Jan 4, 1976

PREFACE During the past year, the Council of the SAIMM undertook a major strategic-planning exercise to review all its current activities, and to redefine its scope and objectives in the light of changing circumstances. The following are the four main concerns that prompted Council to take stock of the situation. (1) Over the past five years, the SAIMM has become heavily involved in a variety of new activities. (There are many examples, of which the expansion in book publications and the establishment of physical metallurgy as a third major discipline with its own colloquia and schools are perhaps the most important.) While these new activities have considerably broadened the SAIMM's scope, they have resulted in a significant increase in the day-to-day workload of the President, Office Bearers, and Council members, and of the secretarial staff based at Kelvin House.

Jan 1, 1986

By D. R. Lawrence

A method for the calculation of the economic optimum spacing of raise connections in 'scattered' mining layouts is described. The method of calculation and the results obtained in a case study are presented. An indication of how the overall optimum spacing (which satisfies both economic and geological considerations) can be determined is also given. " The case study demonstrates that, even with the present strike-cleaning systems,significant savings in working costs can result from an increase in the spacing between raise connections. Furthermore, improvement of the present systems would result in a considerable increase in these savings.

Jan 1, 1983

By H. L. Monro

The price received for a commodity decreases as the quantity sold increases. all other factors remaining the same. This has been the position with gold since it was demonetized in August 1971. The result is that the marginal revenue per kilogram of gold decreases steadily with increased production. If operating losses are to be avoided, the marginal cost of production must not exceed the marginal revenue. This requirement, although not seriously violated by most invididual mines, is not met by the industry as a whole, resulting in large losses of income to the State and the shareholders. These losses are increasing, and a way of curbing or reversing this trend is described.

Jan 1, 1984

By H. E. James

GOLD 100, the most comprehensive international conference on gold ever held anywhere in the world, took place in Johannesburg from 14th to 18th September, 1986. The Conference was followed by a series of one day visits and an extended technical tour. The Conference was organized jointly by the Council for Mineral Technology (Mintek), the Chamber of Mines of South Africa, the School of Business Leadership of the University of South Africa, and The South African Institute of Mining and Metallurgy.

Jan 1, 1986

By P. Geldenhuys, D. J. C. Taylor, D. C. Page

This paper gives a technical review of the history, occurrence, mining, and metallurgy of iron in South Africa. The reserves of iron ore worldwide and in South Africa are reviewed, and potential new developments In the iron-and-steel industry in South Africa are examined. The paper concludes that the exploitation of lower-grade iron deposits will probably supplement the reserves of high-grade hematite ore in the distant future, and that, accepting this scenario. South Africa will be well placed to provide iron ore for its expected internal steel requirements, as well as supplying quality Iron ore for the export market.

Jan 1, 1988

By M. C. van Eeden, R. Vermeulen, K. B. Le Bron

This paper presents the lessons learnt during the transition from an open pit method to a sub-level open stoping method at the Koidu Limited kimberlite pipe. These learnings may assist other mines with planning, both from a practical implementation perspective (layout, charging up challenges), and a method for estimating potential dilution and stability challenges associated with the interaction between the surface and underground excavations. Predictive geotechnical stability modelling was successfully applied to highlight potential failure zones, which allowed modification and enhancement of the mining layouts and quantification of the potential dilution of the kimberlite from indicative instabilities.

Sep 1, 2025

By C. S. Erasmus, L. C. Woollacott

The distribution of gold loaded onto carbon particles from a carbon-in-pulp operation was measured by neutron activation analysis. The nature of the distribution is examined, and the implications for operating plants and CIP simulators are discussed.

Jan 1, 1992

By R. J. Dippenaar, W. H. Van Niekerk, D. A. Kotze

It is generally accepted that alkalis attack and degrade the carbon fraction of coke in a blast furnace. Because South African cokes contain relatively high amounts of ash, the influence of alkalis on the ash fraction was investigated, the carbon and ash fractions being separated and studied separately. Potassium engenders the formation of liquid, with a resultant expansion of volume and a decrease in the strength of the coke ash. However, the ash did not play a significant part in the degradation of the coke, and it was found that the catalytic effect of potassium on the Boudouard reaction was the overriding factor in the coke-degradation process.

Jan 1, 1986

By A. A. Snodgaass

This paper reviews lead as a commodity, starting with a brief historical outline and dealing with the various uses of lead in some detail. It then goes on to discuss some statistics in relation to the production and reserves of lead, before sketching its mode of occurence. The topics are approached in regard both to the world and to South Africa, with the emphasis on the later. The mining and concentration of lead at Black Mountain Mine at Aggeneys in the north-western Cape Province are detailed, before a general account is given of the smelting, hydrometalurgical extraction, and refining of lead, together with the processes used in these activities. The paper concludes with a discussion of safety and health in regard to lead and a brief look at the commodity's future.

Jan 1, 1986

By G. T. Lineberry, C. M. Baird, D. L. Silverstein

The University of Kentucky (UK), with an enrollment of 25,891 in fall 2002, is a comprehensive, public land-grant university located in the Bluegrass Region of Central Kentucky. As the State’s flagship university, UK has long been involved in distance education, first through traditional correspondence courses, followed by use of videotape and satellite delivery in the 1970s and1980s, but soon supplanted by use of interactive television (ITV) and on-line course delivery in the 1990s to date. Today, UK Distance Learning Programs annually administers approximately600 course sections, with services provided to over 5200 enrollees. Courses are offered via six media: interactive video, Internet, on-site, satellite, open-air and cable television, and videotape, with hybrid delivery becoming increasingly popular. The University of Kentucky College of Engineering experience with distance instruction prior to 1985 was limited to videotape non-credit offerings. The Department of Mining Engineering, a small department in terms of numbers of both faculty and students, was a University pioneer in distance education. The first University degree program offered in its entirety by distance delivery(initially by itinerant faculty) was the Master of Mining Engineering. Satellite delivery from Lexington to Cumberland, Kentucky, was a welcomed change of delivery mode in 1987–88,resulting in six hours less travel time for faculty each week. Shortly thereafter, other initiatives directed toward fulfilment of its land-grant mission were undertaken by the College. Use of satellite for course delivery rapidly declined due to limited interactivity, in favour of compressed video and on-site instruction. Classroom sites in the Kentucky Tele-Linking Network (KTLN) now number over 200. The Network links schools, colleges and universities, as well as public and private agencies throughout the State. The KTLN supports voice, video, and data transmission in a uniformly-equipped environment. Beginning in the early 1990s, transfer-critical pre-engineering courses were delivered from Lexington to Kentucky’s community colleges with the largest pre-engineering enrolments. Success was limited, but lessons learned were invaluable. In 1996, the University of Kentucky College of Engineering was asked by the Kentucky Council on Higher Education (the predecessor to the Council on Postsecondary Education) to expand engineering education in Kentucky, first by initiating cooperative B.Sc. degree programmes in Chemical Engineering and Mechanical Engineering on the campus of Paducah Community College (PCC), located 400 km from the UK campus in Lexington. The third partner in these programmes is Murray State University (MuSU), a public regional comprehensive university 80 km south of Paducah. The genesis of the new degree programmes, which were subjected to ABET review in October 2002, as well as a summary of the major accomplishments and challenges of the innovative programmes, will be offered. The limited use of distance technologies for course delivery in these B.Sc. degree programmes will be discussed. A ‘no-spin’ overview of other non-traditional distance-learning ventures within the College of Engineering will be chronicled, with an honest assessment of the motivation for these efforts and, where appropriate, their relative degree of success. Among these ventures are: a BScME and a Master of Engineering programme at Toyota Motor Manufacturing of Kentucky, Georgetown, Kentucky; course exchange in Chemical Engineering between the University of Kentucky and the University of Louisville; an ITV-based Master of Engineering programme for practicing engineers in Kentucky; proposed joint-degree programmes in Civil Engineering and Mechanical Engineering with Western Kentucky University; and a proposed part-time MScME programme in Paducah, Kentucky, with a start date of August 2002, threshold enrolment permitting. Keywords: distance learning, distance education.

Jan 1, 2003

By B. Rohrmann

The paper deals briefly with the history of vanadium, and its uses, price movement, and world resources. It then describes the titanomagnetite ore of the Bushveld Complex, and the production of vanadium from this ore at Highveld Steel & Vanadium Corporation Limited, giving details of the various processes used, including the roast-leach, rotary-kiln, electric-smelting, shaking-ladle, and basic-oxygen-furnace operations. The paper concludes with a very brief account of the treatment of Highveld slags in Europe for the production of vanadium pentoxlde and ferrovanadium.

Jan 1, 1985

By S. W. Evans, G. Pienaar

Weldable steel plate with a good combination of strength and toughness is currently produced from 0,12 to 0,28 per cent carbon low-alloy steel heat-treated by roller quenching and tempering. Alternatively, steel plate of the same strength can be produced at a lower production cost by the use of very-low-carbon steel (0,03 to 0,08 per cent carbon) processed by in-line quenching without tempering. This paper reports the results of experimental work on these steels, and compares them with the properties of conventional steel. On thinner sections, it was found that the properties of the experimental steels compare favourably with those of conventional grades.

Jan 1, 1989

By M. U. Özbay

A series of blasting experiments was carried out in an up-dip stope of a gold mine using short-perioddelay electric detonators. The main object of the investigation was to show the interactive effects of short-delay blasting. The delay range over which observations were made was restricted to between 10 and 200 ms. To quantify the blast results, data were collected on fragmentation, throw, position of muckpile, and ground vibration. For comparative purposes, blasting parameters for conventional pyrotechnic sequential firing were also measured. The paper describes the most relevant parts of the study and gives the experimental results. The interactive effects of short-delay blasting are analysed, and some aspects of the breaking mechanism are discussed.

Jan 1, 1985

"Chairman: Dr N. G. W. Cook Rapporteur: Mr M. P. RobertsPapers:Planning open pit mining operations using simulation by A. Bauer and P. N. Calder Simulation for control of underground liquid flow by G. N. Pitts and P. B. CrawfordEvaluation of production strategies in a group of copper mines by linear programming by P. H. Williams, J. N. Brooke and D. M. PoulterAn equipment maintenance system by D. W. Dean and J. A. RyderTaken as a whole, the difference between the four papers in this session were perhaps more illuminating than their similarities. The titles of the first and second papers contained the word 'simulation', and in both papers random number generation was relied upon in the selection of inputs from empirical distributions, but the nature of the models to which these values were inputs were quite different. The third paper displayed another method of uniting the empirical and the theoretical in a linear programming formulation whose matrix coefficients were measured empirically, and here some apt remarks on computer implementation were included. This paved the way for the last paper which abandoned all theoretical pretensions in favour of a detailed description of computer implementation and perhaps as a result gave rise to the most feeling audience participation.The systems mentioned were developed for the iron, petrol, copper and gold producing industries in the US, Canada, Zambia and South Africa..As with all the parallel sessions, contributions from the floor may have been limited by the shorter time available to delegates to acquaint themselves with the papers before the session. In spite of this, and due largely to the active chairman¬ship of Dr Cook, the discussion during the session which is summarized here contributed much to the information contained in the papers themselves.In his presentation, Dr Calder summarized his paper. He expected that simulation would be used in future on an almost universal basis in open pit mining. It could contribute new knowledge more cheaply than experimentation in the flea For example, this study had shown what was previously thought to be a matter of more shovels and trucks was really a blasting problem, and improving blasting had increased production to the desired level. The simulation had shown that uniformity of truck performance was a desirable factor. It had also been used to study the advisability of a dispatching system.Dr Ramani contended that where equipment characteristics were available, deterministic standard simulation could adequately simulate systems in which interference occurred. Operator performance could be measured against perfor¬mance curves predicted by standard simulation and poor operators spotted and retrained. The present system did not take into account variability in truck loading, for instance. Dr Calder replied that if the number of variables was large, the standard approach became too complicated for operating personnel to follow. He admitted he had not tried it. The variability of truck loading could be coped with easily using the Monte Carlo approach. Operator variability was already incorporated because the time studies are actual."

Jan 1, 2014

By A. Whillier

Recommendations are given for the design of vertical cooling towers for use underground in mines and a method is given for predicting the entering and leaving water temperatures when a given amount of heat has to be dissipated.

By P. M. Swash

A mineralogical investigation of the main causes of refractoriness of some metalurgicaly complex gold ores in South Africa is reported. It is shown that this refractoriness is related to the presence of submicroscopic gold, carbonaceous material, pyrhotite, and base-metal sulphides. Gold ores can be classified according to their content of these components. Electron-microprobe analysis shows that gold occurs in arsenopyrite and pyrite, the gold contents of which can be up to 2700 gft. The gold and arsenic contents of these minerals are closely corelated. Furthermore, within zoned arsenopyrite grains, the concentration of gold closely folows that of arsenic. Mossbauer spectroscopy caried out on samples of concentrate from the Barberton area indicates that the submicroscopic gold within the sulphides is in a non-metalic form. The mineralogical examination of beneficiation products is important, since it sheds light on some fundamental aspects of the behaviour of the ore and gangue components during milling and flotation. Such basic information will lead ultimately to a better understanding of the problems in the beneficiation of these ores. Investigations have shown that the overmiling of the auriferous arsenopyrite and the disseminated nature of the sulphide mineralization are the main problems during beneficiation.

Jan 1, 1988