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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

Jan 1, 1981

The International Colloquium on Developments in Froth Flotation, which replaced the Annual University of Cape Town (UCT)/University of Stelenbosch (US) Minerals Processing Symposium, was held at the Van Riebeeck Hotel in Gordon's Bay on 3rd and 4th August, 1989. The Colloquium attracted 150 delegates from the mining, metallurgical, and chemical industries, including 9 from overseas.

Jan 1, 1989

By R. H. O?Connor, B. N. Soutar

The paper reviews the introduction 01mechanical shaft drilling into the sinking 01shafts in the Gold Fields Group. A comparison is made between the operating costs 01the drilling rig and those of conventional hand-held machines, and it is concluded that, despite certain disadvantages, mechanical drilling is preferable.

Jan 1, 1988

By J. C. David, G. Coetzer

The effect of varying aliphatic, olefinic, and aromatic groups in the N- and S-positions of dithiocarbamates was investigated in the selective and bulk flotation of a mixed copper-lead-zinc-iron ore. Selective and bulk flotation were found to be dependent on the type of functional group, as well as on the position of substitution.

Jan 1, 1989

By M. R. Henzen, J. W. Funke, G. J. Stander

SYNOPSIS The adverse effect of acidic mine drainage derived from gold and coal mining operations on the quality of receiving waters is described, together with measures to be taken to counteract this pollution. The mineral load and the toxic effects from metallurgical and metal finishing industries are also considered. Attention is drawn to water conservation aspects.

The 91st Annual General Meeting of The South African Institute of Mining and Metallurgy was held at Kelvin House, Johannesburg, on 17th August, 1988. Mr B.c. Alberts (President) was in the Chair, and declared the meeting open at 16hOO. Obituaries The President announced the deaths of the following members of the Institute:

Jan 1, 1988

By D. H. C. Griffiths, D. R. Davis, D. B. Paterson

Consolidated Murchison Limited is the only primary producer of antimony in South Africa, producing approximately 18 per cent of the total world production. This paper gives a technical review of the history, occurrence, mining, and metallurgy of antimony at Consolidated Murchison. World antimony markets are also discussed, together with the end-uses.

Jan 1, 1986

By A. A. Hazell

Mine management by objectives By A. A. HAZELL The author discusses the objective areas of mine management. Setting objectives is seen to be a conscious process which starts at the highest level of management. This enables clear objectives to be set at each lower management level. The methods of setting objectives in the areas of stope production, productivity and manager performance are set out in detail. In the area of manager performance emphasis must be placed on the practice of management. It is concluded from results obtained that "management by objectives" produces better than average perormances.

By R. Hutchings

The paper reviews current understanding of the effect of ion implantation on the wear process, and the state-of-the-art of ion implantation as a commercially viable treatment to impart wear resistance. Ion implantation involves the firing of high-energy ions into the surface of a material, which modifies the surface properties and so causes a transition in the dominant wear mode. The process is best suited to specialized engineering applications involving critical dimensional tolerances or surface finishes, but has gained little industrial acceptance because of its poor reproducibility and the lack of a suitable method of inspection.

Jan 1, 1986

By C. Hey

The cycloned gravitated tailings backfill system, also referred to as a soft or low density fill, has been implemented at Vaal Reefs. Inhibiting the success of the system was the problem of shrinkage after placement. The problem was overcome by a pressure fill technique which eliminated settlement, contained costs and allowed remote placement. The technique involves the preinstallation of disposable pipes which are filled cyclically until a residual pressure of 0,5 bar of active support is generated in the filled paddock.

Jan 1, 1988

By A. Whillier

Recovery of energy from the water going down mine shafts by A. WHILLIER, Pr. Eng., Se. D. (M.I.T.) (Fellow) The influence of energy-recovery systems on the rise in temperature of water going down mines is examined. It is concluded that the, cost benefit of such systems, deriving partially from the reduced temperature rise in situations where cold water IS sent underground from surface, would more than justify the installation cost.

Jan 4, 1977

By J. H. Bulloch

A short review is given of the effects of corrosion fatigue on the materials used in pressurized water-reactor vessels. Selected topics such as testing procedures, test data, and mechanisms in simulated environments are discussed. The main fact that emerges is that most of the data on the growth of fatigue cracks reside below the ASME X1 1980 High-R 'Wet' design-code lines, Le. they fall within that specification. Finally, some recent advances in the understanding of the corrosion-fatigue behaviour of such materials in pressurized water reactors are highlighted.

Jan 1, 1987

By R. T. Rudd

The impact of slimes-dam formation on water quality and pollution by R. T. RUDD*, B.Sc., AMI (S.A.) CE (Visitor) This paper discusses the mechanics of pollution by slimes dams in the gold- and fluorspar-mining industry, as well as that caused by coal dumps and slurry dams. The effect of coal mining on two typical rivers in Natal is shown and the implications discussed. The implications and trends of sulphates pollution on the Rand Water Barrage in the Vaal River are discussed. The spread of pollutants (sulphates and fluorides) from the Reef and elsewhere, and the impact on urban use and agriculture downstream of the barrage, are illustrated. Conclusions and future policy are outlined.

Jan 12, 1973

By R. Hemp

The first part of this paper describes the collection of barometric pressure measurements in a mine and their statistical analysis, which shows the effect of variations in barometric pressure, both on the primary emissions of methane gas into the workings (whether from fissures or from the surrounding strata), and on the flow of air to and from large unventilated, or poorly ventilated, areas. The second part of the paper deals with a study, based on computer simulations, of leakage flows of air into and out of sealed areas, and the reduction of such flows by the use of adequate seals.

Jan 1, 1994

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 J. D. Flint

A description is given of the extraction of pillars in a seam of coal which normally varies in thickness from 10 feet to 14 feet using conventional trackless mechanised units. By using the pocket and fender method of pillar extraction, the high capital cost of hydraulic supports is eliminated, and a volumetric extraction of 85% to 90% of the seam of coal is possible. This method of mining opens up the possibility of extracting vast tonnages of coal which hitherto would have been left in situ as pillars. The major benefits likely to accrue from this technique are seen as follows: 1. Greater volumetric extraction of the seam; 2. Longer panel life with less frequent transferring of sections; 3. Preservation of our natural resources. The authors deal with the history of this development at Springfield Colliery, discuss the present results and outline the future trends in the light of current experience.

By F. J. J. Blaauw

This paper discusses a bold venture into the use of interactive computer graphics technology as the foundation of an overall integrated mining managerial system. The wide range of applications that can be addressed through the use of this technology is highlighted, and some discussion of the major facts of this project, which is still in its early stages, is provided.

Jan 1, 1987

By R. J. Davidson, N. Schoeman

SYNOPSIS The paper describes each of the stages in a carbon-in-pulp (CIP) or carbon-in-leach (CIL) plant, and details the steps that can be taken to achieve effective carbon management by referring to practices at the Daggafontein CIP plant. This approach was adopted because of the difficulty in summarizing current carbon management in the many varying operations in South Africa, Daggafontein being chosen as a high-tonnage dedicated well-run plant of recent design. Because of the major role played by the consumption of carbon in the operating costs of CIP and CIL plants, an attempt is made to develop a series of indexes based on quality parameters and price that can be used as a guide In the selection of carbon.

Jan 1, 1991

By P. J. Kinver

This paper deals with the development of the cut-and-fill mining method at the Broken Hill orebody of Black Mountain Mineral Development Company (Pty) Limited, at Aggeneys in the north-western Cape Province of South Africa. Lead, copper, zinc, and silver are produced. Production started in January 1976, being confined to blasthole production methods in the upper, steeply dipping areas of the orebody. This blasthole reserve is 70 per cent depleted, and pillar extraction is in progress. The balance of the production tonnage, 60 kt per month, is produced from three cut-and-fill stopes situated in the flatter-dipping areas of the orebody. The cut-and-fill mining method at Black Mountain is a result of research and planning activities that included the use of modelling, laboratory tests, mathematical analyses, in situ tests, and experience gained from other mining operations. These investigations and the resulting developed methods and designs are summarized in the paper.

Jan 1, 1985