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By J. A. Drummond

The duties and efficiencies of a number of main and auxiliary fans were determined by standard and thermal methods. Some observations on the effect of water and dirt accumulation on fan performance were made.

By I. Bock

This presentation describes a technique under development referred to as Selective Blast Mining. The technique involves millisecond sequential blasting. It applies to mines where the gold bearing conglomerate band is clearly demarcated, and separated from the waste rock in the foot and hanging wall. The width of the conglomerate band should be less than ± 0,7 metres. A research program was initiated in August 1994 by Drs RE. Robinson and I.E. Bock. The objectives were to develop new blasting methods that can reduce: ? the losses of gold in narrow reef stoping. Losses of gold can be as much as 10-15% ? and to introduce selective mining to reduce ore dilution with waste rock.

Jan 1, 1996

By K. E. Mantell

1. TRACKLESS MINING AT OAMITES by K. E. MANTELL Oamites Mine, brought into production in late 1971, is located 50 km south of Windhoek, South West Africa, on the northern boundary of and just outside the Rehoboth Gebied. Oamites was known as a possible mining proposition at the turn of the century when Hanseatische Minen Gesellschaft was adit mining on the adjacent farm Kamzwas. Rand Mines Limited carried out a small amount of prospecting in the early 1960s, Falconbridge Explorations Limited later taking over the prospect. Approximately 4600 m of diamond drilling was carried out between 1965 and 1967.

By R. Kok, N. B. Strydom, P. L. Jooste, W. H. Van Der Walt

Intermittent exposures to heat, and the retention of heat acclimatization by N. B. STRYDOM, M.Sc., Ph.D. (Illinois) (Fellow), R. KOK, M.Sc. (Potch.) (Visitor), P. L. jOOSTE, M.Sc. (Stell.) (Visitor), and W. H. VAN DER WALT, B.Sc. (Potch.) (Visitor) Twenty-one heat acclimatized subjects were assessed for the degree of acclimatization attained with respect to heart rate, rectal temperature, and sweat rate during a standard four-hour heat-stress test. Thereafter, they were put on light duties in cool environm ents for four weeks, except for four hours of exposure to heat every seventh day. Their state of heat acclimatization was again assessed two days after the final week's exposure. Although heart rates and body temperatures showed significant increases over the initial values, no differences were observed in sweat rates and, in general, the subjects were rated as still adequately acclimatized to heat.

Jan 7, 1975

By P. E. L. Balestra, A. O. Filmer

The kinetics of the reactions involved in the non-oxidative dissolution of nickel concentrate in hydrochloric acid were studied by electrochemical and powder-leaching methods. It was found that the rate of non-oxidative dissolution increases with a cathodic shift in the mixed potential, which can be achieved by an increase in the nickel-to-sulphur stoichiometric ratio at the reaction surface. An unactivated concentrate with a sulphur content of 36 per cent exhibited a mixed potential of +O,3V (SCE) and could not be leached satisfactorily in 3 M hydrochloric acid at 60°c. When activated material (18 per cent sulphur) was leached, it had a mixed potential of -O,3V, and high iron and nickel extraction rates. Results reported by other workers on the non-oxidative dissolution of sulphides are explained in terms of the mixed potentials at which dissolution occurs.

Jan 1, 1981

By G. Panopoulos, R. P. King, A. H. Juckes

The flotation characteristics of two South African coals were investigated: one from the Dumacol Colliery in Natal, and the other from Landau Colliery in the WitbankCoal Field. Samples of fine coal (smaller than 1 mm)were studied, the Dumacol coal showing significantly better ash-liberation characteristics than the Landau coal. Neither coal was found to produce satisfactory flotation concentrates, except at very fine sizes. The poor flotation performance can be ascribed to the non-selective flotation of unliberated particles that may contain considerable quantities of ash. Flotation recoveries were greatest for particles between 100 and 200 µ m, and fell of rapidly as the size increased above 200 µ m. Very fine particles were found to float adequately, and acceptable concentrates can be made at comparatively high yields from materials smaller than 75 µ m. The flotation of ultrafine coal was demonstrated successfully in a continuous pilot plant. This result opens the way to a potentially viable industrial process for the beneficiation of ultrafines from the Witbank No. 2 seam, which for decades has been regarded as non-floatable.

Jan 1, 1986

By W. F. Heinz

The efficient and effective handling and logistics of materials for underground support is an important part of mine mechanization and automation. Support systems based on backfill material or grout slurries and pastes transported underground through pipelines (ranges) lend themselves to a large degree of mechanization. In contrast the installation of conventional support systems such as props, timber packs, brick packs etc., requires more handling and hence is labour intensive and more costly. RODIO/ROSOND has developed and improved significantly its high density slurry/low density paste conveyance system on surface and underground during recent years. The surface batching and pumping stations are computer controlled and operate with a minimum labour complement. The RODIO/ROSOND grout pack support system has some unique features such as the use of relay stations, which result in the following distinct advantages and benefits to mining operations: • No interference with shaft operations • No grout ranges under high pressure in shaft • Efficient reticulation from underground relay stations • Low capital cost • Better control of quality of materials (high density slurry/low density paste) placed • Proximity of the working place to the relay station facilitates control of installation. These specific characteristics of RODIO/ROSOND’s grout pack support system have resulted in more economical support for several mines in South Africa and Australia.

Sep 1, 2001

Ausmelt is supplying commercial quantities of an alkyl hydroxamate flotation collector AM28 for flotation of oxide and supergene base metal ores and tailings. AM28 is a non-hazardous product used as a ten per cent to 50 per cent solution in dilute potassium hydroxide. It is a selective flotation collector for oxide or oxidised base metal minerals and replaces conventional sulfidisation for oxide mineral flotation. At Radio Hill, the AM28 is used in conjunction with traditional sulfide collectors, which allows simultaneous flotation of oxide and sulfide copper minerals. The Fox Resources Radio Hill copper concentrator near Karratha, Western Australia, is currently configured to treat supergene copper ore sourced from the West Whundo open pit. This Archean VMS type copper deposit has been deformed and remobilised with uplift, erosion and weathering to form a significant supergene zone. The sulfide copper minerals present in the upper zone are digenite and chalcocite with lesser chalcopyrite and covellite. Oxide copper minerals present include cuprite, with lesser malachite and azurite. Gangue minerals include quartz, talc and chlorite. Plant trials at Radio Hill are reported for supergene West Whundo ore, where the AM28 was stage added into the circuit at nominally 80 g/t. Plant data over three months shows the copper recovery increased consistently from around 50 - 60 per cent to above 70 per cent when AM28 was added. This has been proven statistically. The grade of the concentrate was consistent with and without AM28, at nominally 22 - 24 per cent copper.

Jan 1, 2007

Balance Sheet at 30 June 1989 ACCUMULATED FUNDS Balance at 30 June 1988. Excess of income over expenditure for the year ended 30 June 1989

Jan 1, 1989

By Z. Levinson, R. Dimitrakopoulos

A mining complex is an engineering system where raw materials are extracted from several mines, processed, transported, and sold to the market. The uncertainty and local variability of material grades and their locations within the related mineral deposits are critical for determining the optimal life-of-mine extraction sequence, destination policy, operating modes, and capital investment decisions, which define the production schedule of a mining complex. Infill drilling is used to further characterise a mineral deposit and reveals information that changes the representation of the resource model and potentially the resulting optimal long-term production schedule. A self-learning reinforcement learning approach is proposed to determine the optimal drilling locations that maximise the net-present value of the long-term production schedule and the associated financial forecasts by adapting the schedule to additional information. A case study at a copper mining complex demonstrates a $70 M increase in project value by collecting drilling information with a $1 M budget.

Sep 1, 2021

Mr K.C. Owen started his mining career as a learner official after matriculating at the Parktown Boys' High School, Johannesburg in 1967.

Jan 1, 1991

By O. L. Papendorf

For purposes of simplification, a case is presented for an engineer to discount cash flows in real rather than in current terms when giving evidence in a court of law. The difference between the two methods is highlighted, and a recommendation is made in the case where differential rates apply.

Jan 1, 1981

By R. F. Botha

I want to thank you for inviting me to deliver this, the closing address at the final plenary session of the 15th Congress of the Council of Mining and Metalurgical Institutions. Your Council has an impressive title, and justly so. Consider the expertise, the skill, the capacity, the achievement, that is gathered together here in this room this afternoon.

Jan 1, 1994

By J. L. Taylor

The belt-filtration plant at Chemwes Limited has been in operation for three years. The plant design is discussed. Operational and engineering problem areas are reported, and where possible the modifications or practices that led to their solution are mentioned. Capital and operating costs, together with selected general operating data, are also included.

Jan 1, 1983

By D. I. Nicol

An assessment is made of the possible scope for the use of activated charcoal as the solid adsorbent in an upflow fluidized-bed contactor, and a pilot-plant programme for the recovery of low concentrations of dissolved gold in this contactor is described. It was found possible to produce an effluent that contains less than 0,01 p.p.m. of dissolved gold.

Jan 1, 1997

By G. J. C. Young

The new metallurgical plant has a simple, compact layout, being designed for a small team of operators. The reasons for building the new plant are given, and its various sections are briefly described. These include the conveyor plant, milling plant (for run-of-mine milling), thickener plant, agitator plant, filtration, clarification, smelthouse, and central core joining the mill and filtration sections.

Jan 1, 1978

A back-propagation model, which is typical of the models used in the science of artificial neural networks, was applied to the prediction of gossans from the southeast area of Habei Province in China. A success rate of 100 per cent was achieved. The results show that the neural-network approach is good, and that it can be used effectively in the prediction of multi metallic deposits.

Jan 1, 1995

By R. P. King

The ideas leading to the formulation and utilization of a flotation model are developed. The main theoretical and experimental work that has been carried out by the National Institute for Metallurgy Research Group at the University of Natal is presented. The two experimental flotation plants available to this Group are described.

Minutes of the Annual General Meeting held at the St. Helena Club on Wednesday, 27th July, 1977, at 7.30 p.m. Book review Advances in extractive metallurgy, 1977. Proceedings of the third symposium organised by the Institution of Mining and Metallurgy held from 18-20th April 1977. London, the Institution of Mining and Metallurgy, 1977. 244 pp. £18,50. Coal preparation A meeting of the Organising Committee of the Eighth International Coal Preparation Congress took place in Moscow on 24th and 25th May, 1977.

Jan 1, 1978

MASSMIN 92 edited by H.W. Glen. Johannesburg, The South African Institute of Mining and Metallurgy, 1992. xiii, 485pp. ill. 30 cm. (SAIMM Symposium Series S12). Includes bibliographies. ISBN 1-874832-18-8. R342 (MemberR285; Student Member R218,88. Available in Australia from the AMF Bookshop, 63 Conyngham Street, Glenside, SA 5065 at $A171.00 (approx). This volume is the twelfth in a series of symposia published by The South African Institute of Mining and Metallurgy since 1962. This particular meeting addressed the subject of the underground mining of massive ore bodies.

Jan 1, 1994