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Commissioning of the Cannington processing plant began in October 1997. The nameplate capacity (of 1.55 million tonnes of ore per annum) was achieved relatively quickly. Since then (like many mines) the operation has strived to increase throughput and improve valuable metal recoveries, to offset declining head grades and lift the value of the operation. The processing plant now has the capability of treating over 3.2 million tonnes of ore per annum and in financial year 2005/06 the combined concentrate production exceeded 600 000 wet tonnes, approximately 80 per cent above concentrate output in the first full year of operation (at the design feed rate). This improved performance was achieved by making changes and additions to each of the major unit processes - primary grinding, flotation, leaching, filtering and paste fill preparation. The changes have included: adding a fines flotation circuit, expanding the grinding circuit, adding a pebble crusher, switching from continuous to batch leaching, building paste conveyors and decommissioning the column flotation cleaning circuits. This paper reviews these changes, outlines the current operating practices and discusses the challenges or opportunities that remain.

Jan 1, 2007

By T. N. Moore, E. M. De Souza

This paper details a study conducted in Canada on the use of a drill with two different types of elastomer-covered handles in place of the standard steel handles. One type of handle was covered with a relatively stiff elastomer with a durometer of 70 (referred to as the plastic handle), and the other was covered with a more compliant elastomer with a durometer of 56 (refered to as the rubber handle). It was found that, compared with the steel handle, the overall acceleration at the interface between the plastic handle and the drill operator's hand was 2,5 times less, and that between the rubber handle and his hand was 3 times less. This reduction occurred predominantly in the frequency range above 500 Hz, and was greater with increasing frequency. However, an analysis based on the methodology of an international standard (which places greater importance on low-frequency vibration), indicated that the reduction in vibration levels was minimal. ~he driller himself felt that operation with the plastic and rubber handles was more comfortable, the rubber handle being preferred.

Jan 1, 1991

By N. Saldía, C. Riveros, R. Hills, S. Barrera

The transport of tailings composites provided by different sources is a field of study where a limited amount of research has been conducted. Nevertheless, such systems are important sources of operational difficulties, especially in the case of high clay content tailings. The case presented in the present paper consists of a free surface flow pipeline transporting a composite of two different tailings with high clay content. It has presented operational difficulties such as partial blockages and upstream box and air intake overtopping events. In the present paper, the causes of these difficulties are identified. These include lack of complete mixing of the different tailings, multi-layered flow with low velocity and high yield values with high frictional losses. The pipeline characteristics and performance are analysed in three stages: design, initial operation and enhanced operation, the latter accomplished by means of increasing turbulence in the box located upstream from the pipeline. The last section of the pipeline and another distribution pipeline system located downstream from the pipeline have performed well. The cause of different behaviour of both systems is also assessed.

Jan 1, 2007

By C. O. Beale

This paper is the first part of a two-part review on the subject. , , .. Here reference is made to the place of copper among the elements, Its properties, Its historical significance, and its 'end uses both in general and in South Africa. Its current market situation and its prospects are dealt with briefly. Some account is then given of the mining and metallurgical techniques employed. in South Africa in the production of copper, together with the names of the companies at present Involved and brief descriptions of their operations, ,... . .. The operations of these companies are described In greater detail In Part 11(Apn11985 Issue of the Journal).

Jan 1, 1985

The Iscor Board has given its Mining Division the authority to proceed with detail engineering and design for a Heavy Minerals Project which comprises a mine in Northern Province near Gravelote, a mine in KwaZulu/Natal near Richards Bay and a central processing complex with a beneficiation plant and smelter which will be located near Richards Bay and Empangeni.

Jan 1, 1996

By A. P. I. Popoola

Aluminium AA1200 was laser alloyed with a combination of nickel and titanium diboride using different weight ratios. Chemical reactions took place with the formation of different phases. The characterization of the alloyed surfaces was carried out by x-ray diffraction (XRD), optical and scanning electron microscopes. The alloyed surfaces are composed of the initial phase of Al-Ni dendrites and eutectics of TiB2/Al and TiB2/Ni distributed on the initial phase. Experimental results obtained showed that Al-Ni intermetallics brought about a significant increase in the hardness property of Al; however, these intermetallics are highly brittle and prone to fail by brittle fracture or stress corrosion cracking when put in service. The addition of TiB2 brought about a reduction in the formation of the seintermetallic phases. A microhardness increase of over 10 times the hardness of the substrate was achieved. Keywords Dendrites, intermetallics, metal composite, Nd: YAG laser.

Jan 1, 2011

By H. M. Wells

The influence of economics on the design of mine shaft systems by H, M. WEI.LS, Pr. Eng., M.Se. (Fellow) The purpose of this paper is to review some of the more important economic criteria that must be taken into account when planning the number, type, size, and distribution of the shafts, or shaft systems, required to exploit a block of payable ore. The postulated philosophy governing the selection of design parameters is that of optimization of the financial return per rand of venture capital employed for the project as a whole. While this criterion may not necessarily satisfy the investment objective under all circumstances (as, for instance, where risk limitation is important), it does serve to place the relative economic advantages and disadvantages of specific design features, which may sometimes be in opposition, into correct perspective with respect to the overall economics of the project under the prevailing economic climate at the time of the investigation.

By H. P. Coetzee, V. J. Solomon

As the price of gold increased, so did the viability of mining previously abandoned unpay areas of Stilfontein Mine. After an assessment to confirm the profitability of mining these areas, it was necessary to re-establish access-ways such as haulages, cross-cuts, and travelling ways. Openingup is a labour-intensive, relatively slow operation, and attempts were made to mechanizeand speed it up. Some of the techniques applied and the results achieved, whether successful or not, are discussed.

Jan 1, 1982

By I. M. Wolff, M. B. Cortie

The Stainless Steels '91 Conference, which was held in Chiba, Japan in June 1991, was the fourth in a series of related international conferences on this theme. These conferences have a high profile and currently constitute a premier forum for exchange between researchers and industrialists active in stainless-steel technology.

Jan 1, 1991

By H. L. Monro

The individual supplies of and demands for gold that make up the total supply/demand structure in any year, together with their individual price elasticities, are used to determine the effect of forward sales on the gold price.

Jan 1, 1992

By A. C. Legg

BCL Limited operates a nickel-copper flash smelting operation at Selebi-Phikwe, situated in north-eastern Botswana. The original furnace was commissioned in 1973 and produces a high grade sulphide matte, from its own concentrates plus additional custom feeds, which is shipped to refineries in Zimbabwe and Norway for further processing. In 2004 the company embarked on a study to modernize the flash smelting complex, with an emphasis on extending campaign life, improving the furnace integrity and enhancing throughput and process efficiency. First phase initiatives from this exercise, including the fundamental switch to a single concentrate burner operation of the flash smelting furnace, were implemented in July 2007. This paper summarizes experiences prior to implementation, details the specific improvements made to the flash smelting furnace and associated operations, highlights the improved plant performance after modernization, and outlines second phase expansion plans that are currently under consideration.

Jan 1, 2009

By J. H. Viljoen, N. B. Strydom, J. S. Greyson, C. H. Van Graan

SYNOPSIS Bad eyesight and poor illumination can contribute to the occurrence of accidents in mines. As one part of a study of this problem, surveys of light intensities have been conducted in 19 gold mines. On 17 of the mines the surveys were on one underground level only, whilst in two of the mines more intensive surveys were conducted by measuring light intensities in all areas to determine any inter-mine variations between the levels of illumination. Readings of light intensity were taken underground at stations, tips, winches, stopes, conveyor belts, waiting places, pump stations, fitters' and boilermakers' workshops, ambulance rooms and in haulages. It is concluded that the average levels of illumination in South African gold mines are comparable with those reported in the literature for mines elsewhere. Standardisation of lighting conditions underground could eliminate inter- and intra-mine variation in illumination levels where they occur. A guide to mine illumination practice would assist such standardisation, and help increase the levels and effectiveness of illumination in mines. Some suggestions are made in this latter connection.

By B. G. Fordyce, W. B. Parker

A description is given of the methods used in management planning, pit-equipment selection and maintenance operator training, and formal organization of mining personnel.

Jan 1, 1979

By N. Gibson

The application of oxygen in a copper smelter by N. GIBSON* (Visitor) This paper describes how the problem of increasing the capacity of the Rokana copper smelter was handled, and how oxygen was found to be technically and economically the best solution. The first phase of its implementation is outlined.

Jan 3, 1974

The 88th Annual General Meeting of The South African Institute of Mining and Metallurgy was held at Kelvin House, Johannesburg, on Wednesday, 14th August, 1985. Mr J.D. Austin (President) was in the chair and declared the meeting open at 16h00.

Jan 1, 1985

In August 1978, the National Productivity Institute invited entries for productivity awards, which it intended making as a recognition of firms and individuals who were contributing to the prosperity of South Africa by effecting outstanding improvements in productivity.

Jan 1, 1979

By A. Vogelzang

The paper describes how the level of the water-table was reduced as a result of increased pumping of water from the mine. Because such a condition in an area where there is compactable material above solid dolomite results In surface movement, steps were taken to restore the water-table to its former level. These included the return of water underground via a sinkhole and boreholes, and the piping of water from another mine.

Jan 1, 1978

By J. E. Forbes

Oxygen enrichment of the converter air at Rustenburg Platinum Mines by J. E. FORBES (Associate Member)* An account is given of the adoption of oxygen enrichment to accelerate converting operations and so permit the handling of larger quantities of feed materials. In addition to achieving its object, the use of oxygen-enriched air (6 per cent oxygen by volume) results in an increase in the concentration of sulphur dioxide in the converter off-gas. The slags have the same composition as those produced without oxygen enrichment, and the operation of the converters is easily controlled.

Jan 1, 1977

Blasting in a gold mine has to satisfy the following set of techno economic conditions: good fragmentation, minimum stopped width, minimum number of rock falls, cost effectiveness. Results of a comparative study of the performance of a Low Density Anfo (LDA) and a conventional Anfo (ANFEX) are discussed. LDA appears to be more cost effective. The same borehole volume can be charged with material of reduced specific gravity. The velocity of detonation (VOD) is increased in the case of LDA resulting in more breakage as a result of shock energy than from the energy in the gas phase. This leads to less damage to the excavation and more favourable breakage of the excavated rock. As a result the overall economics of the mining operation is improved.

Jan 1, 1995

By J. N. Van der Merwe

It is shown that the safety factor as calculated traditionally by use of the tributary-area theory is not valid for high-extraction methods of coal mining. An alternative approach is suggested in which the pillar loads are calculated more realistically for the period during which pillar extraction is in progress. This safety factor, which is known as the Extraction Safety Factor (ESF), can be used in determining the effects of strong layers in the overburden on pillar sizes.

Jan 1, 1990