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1. Book reviews Quantitative texture analysis, edited by H. ,}. Bunge and C. Esling. Deutsche Gesellschaft fur Metallkunde, 1982. 551 pp. Reviewer: L. 1\'1.Matthews Boundary element methods in solid mechanics by S. L. Crouch and A. M. Starfield. Reviewer: J. A. C. Diering World mineral statistics 1976-1980. Produdion,' exports,' imports, by Institute of Geological Sciences. London, Her Majesty's Stationery Office, 1983. £18.00 Reviewer: R. P. King 2. New publications Canadian mines,. perspective from 1982. Mineral Bulletin MR 197. Supply and Services Canada, Hull, Quebec K1A 059, Canada. Copper' s changing cost structure, by Commodities Research Unit Ltd (31 Mount Pleasant, London, WClX OAD, England). Petrology of metamorphic rocks, by M. Suk. New York, Elsevier, 1983. 320 pp. U.S. $68.00. Applied geomorphology, by H. Th. Verstappen. New York, Elsevier, 1983.442 pp. U.S.$95.75. Tin and its uses, no. 137, by the International Tin Research Institute. Greenford, the Institute (Fraser Road, Greenford, Middlesex UB6 7AQ, England), 1983. 3. New journals Mining Science and Technology, edited by C. 0, Brawner and B. N. Whittaker, is to be published quarterly in one volume per year by Elsevier. Aluminium, published monthly by Aluminium -Verlag GmbH, P.O. Box 1207, D-4oo0 Diisseldorf 1, F.R. Germany. DM 690.00 per annum. Rock mechanics The South African Institute of Mining and Metallurgy is to hold two schools on 'Rock Mechanics in Mine Management' at the University of the Witwatersrand, Johannesburg, from 23rd to 27th January, 1984, and from 30th January to 3rd February, 1984. The Federation of Societies of Professional Engineers The Federation of Societies of Professional Engineers (FSPE) has been a member of the World Federation of Engineering Organisations (W FEO) for many years and has regularly sent delegates to the biennial conference of that organisation. Second progress report by ASRET The Professional Engineers Joint Council was estabislhed in 1960 and initially its main fWlction was to represent the interests of engineers. Explosives technology The Center for Explosives Technology Research (CETR) has been established at the New Mexico Institute of Mining and Technology (Tech) in Socorro, New Mexico. International Tunnelling Association A conference entitled 'Ita Tunnels 1984' will be held in Caracas, Venezuela, from 2nd to 7th June, 1984. Automation The IFAC Symposium on Automation for Mineral Resource Development is to he held in Brisbane (Australia) from 9th to nth July, 1985.

Jan 1, 1983

By H. C. Voges

An account is given of the tests being conducted by Iscor on the following processes for the beneficiation of coal fines: froth flotation, gravity separation, heavy-medium separation, and pneumatic and column flotation. The coals used in the tests came from the Durnacol, Tshikondeni, Grootegeluk, and Hlobane collieries. The problems involved in the dewatering of fine products are stressed. From a theoretical study of the efficiencies that should be possible for a hypothetical South African coal, it is concluded that future fines-beneficiation plants in South Africa may use standard heavy-medium cyclones for coal down to 1 mm in size, fines heavy-medium separation for the 1 mm to 450 µm fraction, and column or pneumatic flotation for the minus 450 µm fines.

Jan 1, 1991

By M. Wu, X. Zhao

This paper presents an integrated pipeline transport system for thickened coal sludge, which combines pretreatment and pipeline transport with combustion techniques of thickened coal sludge. The pipeline can transport thickened coal sludge with a sufficiently high solids content (about72%?77%) and high apparent viscosity (about 1 000Pa?S?3,000 Pa?S) directly by pipeline having neither use for water nor an addition agent. The transport distance can be as high as 1 000 metres. In particular, the operating principles, key equipment and technical parameters of this integrated system are examined in this paper. The integrated system effectively causes no pollution to the environment because it is completely sealed, and conserves energy over traditional conveyer designs. Keywords: pipeline transport; integrated system; circulating fluidized bed boiler; thickened coal sludge; high solids content

Jan 1, 2007

United Kingdom mineral statistics 1977. Home, D., Squirrell, H. C., and Venkatesan, J. (compilers). London, Her Majesty's Stationery Office, 1978. 156 pp. £10,25. Copper mining and management. Navin, Thomas R. University of Arizona Press, Box 3398, Tucson, Arizona 85722. ISBN 0-8165-0586-1. 426 pp. Illustrated. Price Metal statistics 1967-1977. 65th edition. 1978. Metallgesellschaft AG, Reuterweg 14, D 6000 Frankfurt am Main, Fed. Rep. of Germany. 382 pp. Illustrated. Coal mine ground control. Peng, Syd S. John Wiley & Sons. ISBN 0-471-04121-1. 450 pp. Illustrated. £19.75 clothbound. Associate Professor and Chairman of the Uranium supply and demand: Proceedings International Symposium, London, July 1978. Spriggs, Michael J. and Casteel, Kyran D. (editors). Mining Journal Gemorfologiesewoordelys/Geomorpho logical vocabulary. Van der Merwe, J. S., en De Villiers, A. B. (samestellers).

Jan 1, 1979

By S. Northey, N. Haque, S. Stoddart, W. Bruckard

Development of new technologies and procedures for managing mineral residues and wastes may benefit from a clear understanding of existing tailing management practices. There is a considerable variability in tailing management techniques used in the Australian copper and gold operations, with associated differences and flow-on effects for the mine site water balance. A database was created, capturing a total of 41 copper and gold processing operations in Australia. The database provides information on tailing generation rates, tailing properties (solids contents and particle size distributions) and tailing storage facility (TSF) types and configurations (e.g. total TSF surface area and wetted surface area). Significant variability was found for the above-mentioned parameters. The solid tailing generation rates ranged from 0.5-37 Mt per annum in 2015. Furthermore, both the solids contents and particle size ranges of the tailing were highly site-specific, and largely dependent on the processing flowsheets. Solids contents of tailings ranged from 45-74% by weight whilst P80 sizes of the concentrator (flotation) feed varied from 75-185 μm. The estimated pumping distance was up to 15 km. The presented data can potentially be used to better tailing management strategies by estimating the potential recoverable water and recycling it, thereby thus reducing tailing footprints. Keywords: Tailing management, tailing storage facility, water balance, mine site, flowsheeting

Jan 1, 2020

By C. G. Carey, M. P. Mullins

BHPBilliton is a large (US$32bn market capitalization) diversified mining group. Significant organic growth is planned through the development of a number of mining, processing and oil and gas projects, totalling some US$5.2bn over the next three years. The investment standards underpin the capital approval process, and incorporate the requirements for range and risk analysis of key input variables, including mineral resources. Public reporting codes for mineral resources and ore reserves (such as JORC) stipulate deterministic reporting of estimates, but are generally silent on any requirement for range or risk assessment, although they acknowledge the risk and uncertainty in the production of resource estimates. In contrast, public reporting of petroleum reserves allow for the use of either deterministic or probabilistic estimation, and for the latter, mandate the level of confidence required for proven versus probable reserves. Conditional simulation techniques, popular in the petroleum industry, provide an ideal tool forrange and risk assessment of the range of outcomes of key resource parameters, such as tonnagesand grades. Examples of a diamond deposit and of a porphyry copper deposit are presented. The understanding and quantification of mineral resource risk through a technique such as conditional simulation provides quantified information on the potential upside or downside. These techniques should be more widely utilized in the high-risk minerals extraction industry. Keywords: mineral resources, conditional simulation, risk, capital investment standards, BHPBilliton.

Jan 1, 2003

By L. Raaths

This paper outlines the process of improvement utilizing performance monitors and GPS systems on an opencast strip mine. Its primary focus is to maximize coal exposure by draglines and secondly to improve on those processes impacting directly on the dragline operation. The Aquila (DM2/5 system) navigation and monitoring systems were installed on the overburden drills. Their main function is to eliminate manual staking and positioning thereby ensuring a regular pattern being drilled. Holes drilled to planned depth reduce drill metres and it minimizes coal losses and contamination at the coal interfaces. The CAES (Computer Aided Electronic System) will be installed and evaluated on the Caterpillar D11 dozers at Optimum. This system ensures a correct dragline pad elevation through the use of planned elevations and GPS technology to achieve the optimal pad elevations for draglines consistently. The draglines are equipped with a Dragline & Operators Performance Monitor. This monitor allows the operator to control his own performance. It reports on all productivity, method and poor operating techniques. These monitoring systems send critical operational information back to the office. This source data resides in central databases from where it is converted and integrated into management information. To manage an operation means that you as a manager must be able to set objectives and targets and to achieve your goals the activities involved must be measurable.

Sep 1, 2001

By L. R. Nelson

The efficiency and cost-effectiveness of the aluminothermic reduction process in the production of ferro-alloys and 'pure' metals depends strongly on appropriate balancing of the process energy required. Insufficient energy results in a poor metal yield, while over-supply can result in excessive fuming and possibly even ejection of the reactor contents in a potentially dangerous 'thermite bomb' reaction. This situation becomes even more critical when the suitability of limited quantities of oxide from new sources must be evaluated, dictating smaller-scale testwork. The resulting higher relative heat losses from the system complicates control of the energy balance, and usually requires the addition of thermal boosters or reactant preheating in order to sustain an autothermic process. This often detracts from the quality of the metal product, and adds to the hazards of batch aluminothermic- reduction testing. The development of a small-scale method (producing less than 2,5 kg of metal) for the plasma-assisted aluminothermic reduction of chromium oxide that overcomes such difficulties is described. The technique involves the use of a sealed 50 kVA plasma-arc furnace to provide controlled electrical ignition and supplementary energy to the reactants contained in a water-cooled copper crucible. The application of the method to the evaluation of the aluminothermic production of pure chromium metal from a unique chromic oxide source is reported.

Jan 1, 1996

By M. S. Janssen, J. L. Taylor, M. A. Ford, E. B. Viljoen, H. A. Simonsen

The Stilfontein and Buffelsfontein Gold Mines, near Klerksdorp in the Transvaal, had accumulated a large amount of uranium-containing residue and, when the price of uranium rose in the 1970s, consideration was given to the possible recovery of this uranium. Preliminary tests showed that concentration of the uranium prior to leaching would not be economic. However, the pyrite in the residue could be concentrated by flotation, and the flotation concentrate could be roasted to pro¬vide both enough acid for leaching the uranium and a calcine from which the gold could be recovered. The feasibility study showed that a uranium operation of 270 kt per month would be most economically attrac¬tive, and a plant of that size was accordingly designed and built. In the first six years of its existence, the plant treated over 20 Mt of residue and produced about 3,5 kt of uranium oxide. During that time, the plant was con¬tinually being improved to make it more reliable and cost-efficient. This paper analyses the operation of the plant during its first six years from the viewpoints of its mechanical, process, and economic performance. The criteria on which the selection of the process was based are reviewed and compared with the actual performance of the plant, emphasis being placed on the leaching, solid-liquid separation, recovery, and purification stages.

Jan 1, 1987

By J. L. Louw

The utilization of centralized blasting systems is progressively becoming a feature of the South African mining industry, owing to increased pressure from the Department of Mineral Resources (DMR) to ensure safer blasting conditions. The purpose of a centralized blasting system (CBS) is to ensure reduced blasting-related incidents and to improve the underground working environment for the mine?s employees. The brief from Samancor Western Chrome Mines (WCM) pertaining to this study was to explore?at a conceptual level?all variables pertaining to the implementation of the CBS. Studies have indicated that Sasol?s SafeBlast? was preferred due to low overall risks and user-friendliness. Empirical observations, however, indicated that attention should be given to the current shaft-clearing procedure and to the installation of additional transformers. This is required to co-ordinate the power supply from 2 level to 10 level with the required supply of the network slave station. A cost analysis indicated that an electronically initiated CBS will result in a R24 cost increase per panel, which relates to a mere 1% cost increase per panel. This cost, in addition to the R1.1 million capital cost, proved to be negligible in comparison to the possible direct and indirect costs incurred by the mine in the event of a blasting-related incident. It was found that Samancor should conduct further studies incorporating the necessary requirements to ensure a successful transition, while considering all stakeholders on the mine. This study proved that the transition to a CBS would ensure safe and efficient blasting at Samancor?s Mooinooi Mine.

Jan 1, 2012

1. Journals Quarterly Journal of tke International Tin Research Institute, edited by Colin J. Evans and published by the Institute, Fraser Road, Greenford, Middlesex UB6, 7AQ, England. Engineering, building and construction law review, edited by P. C. Loots and published every two months by Construction Law Review (pty) Ltd (P.O. Box 78020, Sandton 2146, Transvaal), R63,00 per year. 2. Publications of the Mineral Policy Sector Nepkeline syenite and feldspar by B. W. Boyd Potask by G. S. Barry Selenium and tellurium by D. A. Cranstone Sodium sulphate by G. S. Barry Tungsten byG. G. Law-West 3. Mintek reports Report M114 Analytical methods associated with the recovery of uran~um. Report M117 An assessment of tke merits of various types of balls in tke milling of ores. Report MU1 Tke determinatl:on of trace elements in coal by atomic

Jan 1, 1983

This International Mine-Surveying Conference will take place in Budapest (Hungary) from 5 to 14 June, 1972. Detailed information can be obtained from the Mine-Surveying Working Committee of the Hungarian Mining and Metallurgical Society. Write: OMBKE Bányaméröi Munkabizottsag Budapest, V., Szabadsag ter 17, Hungary. SYMPOSIUM ON NICKEL The 'Gesellschaft Deutscher Metallhiitten-und Berglaute' is holding a Symposium on nickel on 24-25 September, 1970 at Wiesbaden, on the occasion of the G.D.M.B. Annual Meeting. Some 24 papers will be presented by metallurgists from many important companies around the world. Information may be obtained from The Secretary, G.D.M.B., Postfach 210, 03392 Clausthal-Zellerfeld, German Federal Republic. VISIT TO THE COUNCIL FOR SCIENTIFIC AND INDUSTRIAL RESEARCH On 23rd June, 1970, members of the Institute visited the C.S.I.R. in Pretoria. More members had booked for this tour but the current flu epidemic caused cancellations which was unfortunate. The visit was organised with military precision, which prevented detailed discussion of any particular subject, but provided a bird's eye view of a large number of interesting projects. The visit was packed with interest for all and those requiring further information were invited to contact the relevant divisions afterwards. Or Denkhaus welcomed the delegates and stressed the importance of integrating research efforts with industry's requirements. An excellent colour and sound film was shown which depicted the work of the Rock Mechanics division. This showed very clearly methods used for preparing rock samples and demonstrated the machines and instruments for the various tests. It made one realise the extent to which this research has been integrated with the actual mining situation. The fullscale experiments underground showed the failure of pillars under applied loads and were very interesting. This is undoubtedly a film which all mining people should see. After the film the rock mechanics laboratories were visited where the actual machines were seen and described. We then visited the metal and strength mechanics sections where the metallurgists were able to see some interesting experiments and tests. We also visited the Aeronautics Research group where a large 1 000 hp wind tunnel was inspected. We were told enough about this to realise something of the complexities involved in the design and operation of a closed circuit tunnel of this type. The tunnel is used for tests on models which are necessary for the design and modification of aircraft. After a very excellent lunch at the C.S.I.R. recreation centre, the delegates attended two lectures-one by Mr. Mandersloot of the Chemical Engineering group, who outlined the varied functions of this group and told us something of their work. Of particular interest was the research into the suitability of various South African manganese ores for dry cell batteries. Work on the thickener settlement studies interested the metallurgists. The second lecture was given by Mr Donaldson of the National Building Research Institute. This Institute has about ten divisions each of which covers a particular aspect of building research. The work of the soil mechanics division was described in detail and illustrated by coloured slides. This was particularly interesting and demonstrated clearly how building failures result from lack of attention to detail of construction where unstable soil conditions exist. Cracks in walls of compound blocks brought the subject home forcibly to the mining delegates. This division has also caried out important work on sinkholes and sUmes dams and produced some positive results. Altogether the visit was most interesting and enjoyable. It was made more worthwhile because the emphasis was on the work being carried out and not on just seeing the laboratories. The Institute is greatly indebted to the C.S.I.R. and its staff for the very excellent arrangements made.

By M. B. Cortie

The historical development of materials engineering in the mining industry Is briefly reviewed, and some of the factors currently influencing the industry in South Africa are discussed. Material usages in various parts of the mining operation are surveyed. The predominant mechanisms in the degradation of materials in mines are wear, corrosion, and fatigue. The issue of corrosion-abrasion Is considered, but it Is concluded that abrasive wear predominates in most rock-handling and comminution applications and that, in general, little economic benefit Is to be gained in those applications by the use of existing corrosion-resistant alloys. However, alloys with a measure of corrosion resistance find profitable application elsewhere in the mining environment. The use of other engineering materials such as polymers, ceramics, al1l1inium, and various ferrous alloys may be economically viable in a variety of niche situations. Identification of the most cost-effective material in each case calls for a systematic approach and some patience.

Jan 1, 1996

By P. R. Jochens, D. D. Howat, M. S. Rennie

The slags arising from ferrochromium plants were simulated by additions of CaO and Fe2O3 (6 per cent each), Cr2O3 (7 and 12 per cent), and Fe2O3 and Cr2O3 together (6 and 12 per cent respectively) to slags in the MgO-Al2O3-SiO2 system. These additions were made to slags having an SiO2 content of 45 per cent and an MgO-to-Al2O3 ratio of 4 to 3 or 3 to 4. The effect of these oxide additions on the liquidus temperatures, electrical conductivities, and viscosities was determined. The additions of CaO and Fe2O3, although having little effect on liquidus temperatures, decreased viscosity and increased electrical conductivity. The addition of Cr2O3 raised the liquidus temperatures considerably, and tended to decrease viscosity in the temperature range 1 700 to 1 800°C and to increase electrical conductivity.

A method is proposed for the evaluation of the influence of grout prestressing systems on the support resistance offered by timber packs. It is shown that, in order not to reduce the load-carrying capacity of timber packs, grout prestressing systems need to be at least as stiff as a single timber rise. The method was used to establish strength specifications for the grout prestressing systems to be used under non-seismic and seismic conditions. For non-seismic requirements, the 24-hour grout strength needs to be at least 1,7 MPa, and the 7-day grout strength 4,9 MPa. The investigation showed that the proposed strength specification is realistic in the light of current grout-strength capabilities. For seismic requirements, the grout strength needs to be at least 4 MPa and 8 MPa to prevent extensive damage to the grout during seismic events with a peak velocity of 1m/s 3 m/s respectively.

Jan 1, 1996

By A. M. Starfield

Discussion J. de V. Lambrechts (Fellow): The author's paper is a brilliant follow-up of an earlier paper by Starfield and Dickson.1 I have no quarrel with Dr Starfield's computerization of a complex problem, but I do not believe that he is getting quite the right answers from his programme. My impression is that his predictions about wet bulb temperature increases in very deep mines are over optimistic; in other words, that it will be hotter than Dr Starfield predicts. This is putting my views in a nutshell. This is not the occasion on which to indulge in lengthy argument about the original paper by Starfield and Dickson, but the present paper is, after all, based directly on that earlier paper and if the one fails, the other cannot succeed. I did level certain criticisms at the first paper and cannot say that the authors' replies were very convincing. I do not think it is a sin to admit that I belong to the old school which believes in thorough field experimentation and practical trials and no amount of mathematical manipulation or physical theorizing, no matter how excellent, can make up for inadequate practical confirmation. This, as I see it, is still the crux of the matter. The original paper by Starfield and Dickson still rests on somewhat scanty practical evidence and I would be much happier if Dr Starfield's computer programme, based on the Starfield-Dickson model, had been checked against a large mass of observations in the practical mining situation. This is what both Wiles2 and myself3 had tried to do previously. What we lacked in mathematics and/or computer aids, I think the present paper by Dr Starfield lacks in practical substantiation. This is no condemnation of the author's paper which, taken by itself, is excellent but I think the final stage is still lacking, namely the bringing together of theory and empiricism in a manner acceptable to all. This may be wishful thinking on my part but I hope, within the next year or so, to come up with a modified Starfield-Dickson model in such a way that the computer answers will agree in the majority of cases with the few hundred field observations which are already on record. It might be a case of applying the proverbial 'Cook's Law' to the Starfield-Dickson model! REFERENCES 1. STARFIELD, A. M., and DICKSON,A. J. 'A study of heat transfer and moisture pick-up in mine airways.' J. S. Air. Inst. Min. Metall., 68, (5), 1967. 2. WILES, G. G. 'Wet bulb temperature gradients in horizontal airways.' J. S. Air. Inst. Min. Metall., 59, (7), 1959, p. 339. 3. LAMBRECHTS, J. DE V. 'Prediction of wet bulb temperature gradients in mine airways.' J. S. Air. Inst. Min. Metall., 67, (11), 1967, p. 595. R. Hemp (Visitor): Dr Starfield's paper has very effectively rounded off one particular aspect of the general problem of heat flow in mines. The ease with which this computer programme can be used to calculate temperature increases in horizontal airways must lead to its wider use in ventilation planning and, in developing this rapid method, Dr Starfield has indeed rendered a valuable service to the mining industry. One could consider further instances of heat flow in airways in which the availability of a rapid computer method would be desirable, e.g. the flow of air down a shaft, where there is an increase in temperature due to adiabatic compression, as well as an increase in virgin rock temperature as the depth increases. However, this particular case would not present any new problems and would merely require an extension of the exisitng work. I should like in this contribution to talk about an aspect of environmental control in mines which, I think, will become more important in the future. It is well known that wet bulb temperatures are subject to fluctuations underground. In some instances, particularly in stopes, the fluctuations, both with time and position, can be considerable. The theoretical work which has been carried out on temperature increases has been aimed at the prediction of mean temperatures, and no account has been taken of fluctuations around this mean. It is questionable whether this approach will, on its own, be sufficient, particularly when temperature increases in stopes are considered. The fluctuations in air temperatures underground arise from two causes. The first of these would be the fluctuations in surface conditions, and here one could list random, diurnal and seasonal fluctuations. The second cause is the multitude of things which vary in a mine and here one could list variations in air flow quantity, sources of evaporation, heat transfer from pump and compressed air columns and, particularly in the stope, variations in air flow patterns. Fluctuations arising from surface temperature variations should be amenable to calculation, and here one envisages figures relating the decay of temperature variation with distance to factors such as air flow quantity. Fluctuations resulting from changes in the mine are perhaps more difficult to tackle theoretically and the best approach could well be to analyse underground observations. In this connection, there is a good case to be made for the increased use of statistical methods in the analysis of underground temperature measurements, and it might be of value to look at current air-conditioning practice. When carrying out cooling load calculations for a particular location it is customary to use design wet bulb

Jan 11, 1969

By H. Cevizci

In this study, a newly developed plaster stemming method is studied and compared with the usual dry drill cuttings stemming method for surface blasting in mines and quarries. Drill cuttings are generally used in open pits and quarries as the most common stemming material since these are most readily available at blast sites. However, dry drill cuttings eject very easily from blastholes without offering much resistance to blast energy. The plaster stemming method has been found to be better than the drill cuttings stemming method due to increased confinement inside the hole and better utilization of blast explosive energy in the rock. The main advantage of the new stemming method is the reduction in the cost of blasting. In one series of blast tests, blasting costs per unit volume of rock were reduced to 16 per cent by increasing burden and spacing distances. Also, better fragmentation was obtained by using the plaster stemming method. Blast trials showed that plaster stemming produced finer material. In the same blast tests, +30 cm size fragments reduced to 5.4 per cent of the total, compared to 37.7 per cent in the conventional method of drill cuttings stemming. With this method of stemming, vibration and air shock values increased slightly due to more blast energy being available for rock breakage, but these increased values were small and under the permitted limit for blast damage criteria.

Jan 1, 2012

By J. L. Gaigher

A simple mineralogical regression model is described, which was devised in order to help the flotation plant cope with rapidly changing headgrades and feed mineralogy. Minerals in the feed were determined by means of quantitative X-ray diffraction and compared with plant performance parameters and flotation reagent consumption rates, using regression analysis. A mineralogical regression model for predicting recovery served to motivate flotation plant personnel and also set standards whereby flotation performance could be measured. The reagent consumption model indicated in which direction any or all of five flotation consumption rates should be altered. All practically measurable parameters, even those showing poor or no correlation, were included in the model, provision being made for the continuous update of a batch of data of 30 lines. Compared with the method of multiple linear regressions, the r2 is poorer at 0,41 (versus 0,50), but the mean standard error of estimate for both methods is identical at ± 6,6 units. The regression model is simpler than the method of multiple linear regressions, and although the accuracy of prediction is not high (41%), the mineralogical regression model proved to be successful in practice. Flotation efficiency, as measured by the mean ratio of head to tails grade, for the 9 month period after the mineralogical regression model was implemented on an hourly basis, improved from 2,8 to 3,2, which is equivalent to an improvement in average flotation recovery of 5% relative.

Jan 1, 1987

By Z. Nzimande

The Constitution of the Republic of South Africa advocates the importance of sustainable economic development and justifiable environmental consciousness by business. The government needs to ensure that every citizen of the Republic has access to an environment that is protected, pollution free, and sustainable by enacting certain regulations. However, there are more than 5 700 derelict and unrehabilitated mines of all types in South Africa. Former asbestos operations were among the first to be targeted for clean-up under the programme instituted by the Department of Mineral Resources (DMR), owing to the proven direct impact of asbestos pollution on health. This paper seeks to investigate the challenges faced by the coal sector as far as mine rehabilitation and closure is concerned. For the purpose of this paper rehabilitation is defined as per the Chamber of Mines Rehabilitation Guidelines publication, which defines rehabilitation as putting the land impacted by mining activities back to a sustainable and usable condition. Some of the current rehabilitation challenges are technical skills (know-how), leadership focus, poor planning, cost saving initiatives, and the government's lack of capacity to enforcement rehabilitation requirements. It is imperative that mining companies identify rehabilitation as a critical strategic pillar that directly influences license to operate. The case study evidence indicates that relevant policies, appointment of accountable people, sufficient leadership support, and the correct choice of rehabilitation equipment can assist to improve the rehabilitation and land management challenge.

Jan 1, 2012

By M. F. G. Bruce

Two backfill systems have been developed on West Driefontein, namely the centrifuge dewatered tailings system and the cyclone-classified tailings system. Modifications to the two systems since the publication of the original paper (Close and Klokow, 1985) are discussed in addition to the results obtained. Considerable experience has been gained from the operation of the centrifuge dewatering units as well as the placement of dewatered tailings in a difficult mine environment. The centrifuge dewatered tailings method has proved successful in the extraction of a highly stressed block of ground at No. 5A Sub-vertical Shaft. The utilization of backfill support in this area made it possible to dispose of a high-grade barrier pillar. This pillar was considered necessary prior to the introduction of backfill support. The recovery of the gold from this pillar made the use of dewatered tailings backfill cost- effective, despite high labour and maintenance costs. Current experience with the bagfilling method of placing cyclone- classified tailings indicates that it is viable and requires considerably less capital investment. Although expensive at present, it is envisaged that costs will decrease once cheaper bags and other forms of stope support are used. The placement of backfill in small-diameter sausage-type bags requires no change in mining cycle and allows the backfill to be placed close to the stope face. Both backfill systems are being expanded but preference is to be given to the cyclone-classified tailings system.

Jan 1, 1988