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By B. N. Soutar

The design and operation of a double- V compartment vertical-flow settler by B. N. SOUTAR, B.Sc. (Mech. Eng.) Wits. (Visitor) This paper describes the development of a vertical-flow settler for underground pumping installations in the mines of Gold Fields of South Africa Ltd. The recommended settler employs the principle of 'dynamic filtration': the solids that are in suspension in mine water are filtered through a stable horizontal bed of flocculated particles, a technique that was established in about 1958.

Jan 3, 1977

By E. Mpoloka

Debswana together with ADP as their design partner have embarked on an RDP project at Jwaneng Mine. The objective of the project is to install a 2 million ton per annum mineral processing plant that will fast track the recovery of diamonds from the Debswana tailings resource to ensure maximum return on investment for the company. Due to the prevailing economic conditions Debswana has had to review the way they used to build plants in the past and consider simple, fast and effective ways of doing things. The rapid deployment plant concept is therefore the most suitable means of achieving this objective. Debswana is also considering an operating partner who will operate far more efficiently and cheaply compared to the larger more cumbersome and less agile Debswana.

Jan 1, 2010

By I. R. Phimister

'Ancient' mining near Great Zimbabwe I. R. PHIMISTER. B.A. Hons. (Nottingham). B.A. Spec. Hons. (Rhodesia) (Visitor) In proposing reasons for the geographical location of Great Zimbabwe, the paper re-examines the popular assumption that Zimbabwe is comparatively remote from the known areas of 'ancient' goldmining. The lack of 'ancient' workings in the neighbourhood of Zimbabwe is pointed out, and it is suggested that the mining of placer deposits of gold may have played some part in the development of Zimbabwe on its particular site.

Jan 1, 1974

A decision by joint-venture partners Anglo American, Gencor, and the Industrial Development Corporation to proceed with the expansion of the Columbus Stainless Steel plant in Middelburg will contribute significantly towards the economic growth that South Africa needs so desperately. The expanded facility, expected to come on-line in 1995, will be the largest single-plant producer of stainless steel in the world, and the company will rank sixth overall in world production.

Jan 1, 1993

Mr R. C. J. Goode (President) was in the Chair. There were also present one hundred and thirty-six Members, including Messrs R. J. Adamson, Dr J. M. Bereza, Messrs M. Barcza, H. Britten, H. E. Cross, J. K. E. Douglas, G. W. Holl, Dr J. P. Hugo, Messrs C. J. Irving, P. Lambooy, Prof J. de V. Lambrechts, Mr D. G. Maxwell, Dr J. T. McIntyre, Prof R. P. Plewman, Messrs J. F. Reid, V. C. Robinson, H. Simon and P. W. J. van Rensburg (Council Members), G. Abdinor, C. B. Anderson, H. F. Allan, E. L. Atkinson, V. C. Barnes, J. F. Bennet, W. W. Bath, R. E. Barnes, C. L. Berrange, J. P. Buds, Dr W. Bleloch, Dr L. A. Bushell, Messrs D. L. Carson, D. D. Cornier, R. S. Cooke, R. R. M. Cousens, J. P. Coetzee, W. L. Cousens, J. Daniel, R. Daniel, D. G. Davies, S. K. de Kok, V. S. Dillon, B. S. Dykhouse, Dr H. G. Denkhaus, Dr R. S. J. du Toit, Messrs J. I. L. Edwards, R. C. Espley-Jones, J. C. Ferguson, D. T. Fourie, A. Frost, W. R. Flook, Dr N. P. Finkelstein, Messrs D. F. H. Grave, J. M. Gosnell, E. K. Gibson, R. W. Grout, E. W. Gray, J. S. Hay, F. G. Hill, H. N. Hepker, J. P. Hoffman, C. G. Hodges, D. M. Jamieson, Dr D. G. Krige, Dr N. P. Lategan, Messrs J. E. Laschinger, J. Levin, C. P. Linsell, J. O. Kempe, F. Q. P. Leiding, A. I. Lee, D. G. Malan, W. Malan, H. W. McCulloch, R. D. R. Munro, C. S. Macphail, Dr T. F. Muller, Dr A. J. Nel, Messrs S. C. Newman, G. G. Nicolson, G. Y. Nisbet, J. A. Papenfus, E. Pavitt, W. H. Pittie, P. C. Pirow, P. G. D. Pretorius, N. F. Peverett, R. P. Plaskett, M. P. Pearse, W. Pilkington, T. K. Prentice, Dr R. E. Robinson, Messrs R. B. Richardson, R. St. J. Rowland, R. J. Rouillard, F. O. Read, W. T. Ruhmer, D. Savile Davis, E. F. Statham, K. Smith, H. Simon, G. B. Stern, C. D. Storrar, Dr N. B. Strydom, Messrs J. H. Talbot, A. H. Taute, J. H. Taylor, G. W. Thiel, K. A. Tweedie, W. E. Vance, Dr H. J. van Eck, Messrs L. W. P. v. d. Bosch, P. A. von Wielligh, N. B. Vinson, S. J. Venning, W. M. Walker, D. T. Watt, Dr H. J. R. Way, W. T. L. Wayman, R. G. Williams, L. G. S. Wright and C. F. Ziervogel. Thirty Associate Members, including Messrs E. Collier, G. Douglas, D. H. Gray, H. G. Gericke, R. Hemp, N. M. Hayne, A. Hazell, P. M. Johnston, D. E. Love, Miss V. E. Marting, Messrs R. G. Matthews, P. Malpage, D. Nicolle, R. Pendreigh, J. J. Rosslee, R. W. Shearer, R. F. Taylor, G. C. Thompson and D. A. Viljoen. Three graduates, Messrs G. S. Giles, J. P. Hatfield and J. A. Jones. Five Affiliates, Messrs A. C. Collie, E. Collier, A. B. Cook, W. Jacobs and G. M. Thain. Two Students, Messrs C. J. Bircher and R. P. Henrard.

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 P. S. Piper

In the 1960s it was suggested that the volume of stope convergence, and hence the rockburst hazard, could be reduced by the emplacement of backfill. Recent advances have facilitated the placement of large quantities of backfill underground, and a reassessment of its potential benefits as part of a regional support strategy is now timely. In this paper the principal criteria of effectiveness of backfill are taken to be its impact on face energy release rate (ERR) and average pillar stress (APS) levels, and maximization of acceptable ore extraction ratios. The possible effects of backfill on excess shear stresses (thought to modulate large seismic events) are also briefly reviewed. Analytic solutions describing backfill properties and their impact on ERR and APS in certain idealized geometries are also presented, and compared with the results of an extensive suite of computer simulations, in which parameter sensitivities are explored. Results indicate that a regional support strategy is required at depths exceeding 2 km in order to maintain acceptable levels of ERR, and backfill ribs can on their own fulfil this role at depths less than 3,3 km. At greater depths use of stabilizing pillars becomes imperative, but here too supplementary backfill ribs can reduce ERR and APS levels and permit significant increases in ore extraction ratios.

Jan 1, 1988

Council for 1998/99 President R.P. Mohring President Elect J.R. Dixon Vice Presidents Senior M.H. Rogers Junior Dr L.A. Cramer Immediate Past President Dr N.A. Barcza Honorary Treasure J.A. Cruise Members of Council J.P.W. Bennie E.G. de Villiers A.A.B. Douglas F.M.G. Egerton R. Graham Dr R.G. Gürtunca Dr R.V.R. Handfield-Jones P.J. Knottenbelt R.G.B. Pickering* P.S. Piper Prof. R.F. Sandenbergh Dr T.R. Stacey D.J. van Niekerk P.J. Venter J.C. Viljoen

Jan 1, 1998

In the previous chapters we did not concern ourselves with the fact that the geostatistical properties of the regionalized variable x (z) are affected by the size of the support w. Ideally, when analysing an ore body O, we would like to determine the properties of point values in O, i.e. the properties of a regionalized variable with an infinitely small support, say w°. In practice, point values are never known. To measure the value of x at a point z we must take a sample of size w centred at z. For example, if we are interested in the grade at point z, w will be the volume of the sample 'centred in z; if we are interested in the metal accumulation at point z, w will be the area of the cross-section of the sample centred in z. We say that the measured property is a regularized variable, and so the semivariogram (or covariogram) calculated from the values obtained is also regularized. In the majority of the mining problems which can be solved by geostatistical methods, we are interested in the properties of blocks of ore and of samples with a finite non-point support. It will be shown in the following chapters that these problems can be solved by calculating the average value of the point sernivariogram in volumes or areas of finite dimension, or between such volumes or areas. These calculations would be simple if we knew the point semivariogram. This means that the point semivariogram has to be estimated from the observed regularized semivariogram(s).

Jan 1, 1978

By Paul Fouche

The past decade has seen a tremendous revival of the base metal industry in Africa, coupled with an unprecedented increase in the prices of base metal commodities in the last couple of years. The theme of the 4th Southern African Base Metal Conference, is therefore, ?Africa?s base metals resurgence?. This conference will explore the contributions made by the mining and metallurgical disciplines to the base metals industry in Africa. It will also investigate how the base metals industry in Africa can capture the maximum potential from the increase in base metal prices through research, innovative thinking, new ways of operating and project implementation. The conference will also consider the influence of Europe?s REACH programme on the base metal industry in Southern Africa. The conference will include a technical visit to Rössing Mine (Uranium) and will be followed by technical visits to Ongopolo (copper), Skorpion Mine (zinc) and Rosh Pinah Zinc Corporation(zinc and lead). The conference, to be held in Swakopmund, Namibia, also confirms the commitment of the Southern African Institute of Mining and Metallurgy (SAIMM), to hosting a regular forum on base metals in the Southern African region. Swakopmund is an ideal conference venue for local and international mining and metallurgical professionals to be exposed to the latest advances in exploration, resource evaluation, projects and technological advances in Southern Africa?s base metal industry. The organising committee is looking forward to your participation at the conference in July 2007.

Jan 1, 2007

Toxic gases, mostly carbon monoxide (CO) and nitrous oxides (NOx), are invariably generated by commercial explosives under practical conditions of usage because of oxygen unbalance and non-ideal chemical reaction. Permitted explosives are statutorily required to meet the criteria stipulated by regulatory authority for their toxic fume quality for their safe use in underground coalmines. Solid blasting using P5 explosives contribute around 60% production from Indian underground coal mines. Low pull and yield per blast in solid blasting has been identified as a reason for low production and productivity of Indian underground coal mines. In an effort to improve performance of solid blasting, it was envisaged to apply air decking between suitable P5 explosives using high density polyethylene (HDPE) spacers under a Ministry of Coal, Government of India funded project. A non-deflagrating slurry explosive composition having high air gap sensitivity was specially developed for this purpose, so that air decked cartridges get detonated sympathetically with single priming. However, statutory authority in India apprehended that the use of oxygen negative HDPE spacers can influence the generation of toxic gases. The effect of using HDPE spacers on the generation of toxic gases was studied under simulated laboratory conditions with newly developed as well as with three commercial P5 explosives. The results of studies presented in this paper revealed that the level of carbon monoxide increases linearly and there is no significant effect on the level of oxides of nitrogen due to the use of HDPE spacers with selected explosives. Studies also revealed that this newly developed slurry explosive can be used for air decking up to 15 cm using HDPE spacers of weight not more than 21 g without exceeding the permissible limits for toxic gases.

Jan 1, 2008

By D. M. C. Valbom

The introduction of new diamond sorting technologies as well as additional manufacturers I vendors, has increased the equipment selection and combinations available for recovery flowsheet design. This paper describes the methodology used and the benefits realized in the design of recovery plants by ensuring a fundamental understanding of the advantages and limitations of the technology embodied in the equipment, a comprehensive knowledge of the ore body characteristics, and the effective matching of this information in combination with operational commercial requirements.

Jan 1, 2010

By P. van der Westhuyzen

Gone are the days of stock-standard diamond beneficiation and final recovery circuits that could, with minor modifications, be adapted to treat any diamond-bearing ore source. A new era has dawned, offering the opportunity to streamline existing diamond processing operations or develop simpler, more efficient, and economical diamond processing plants, with the focus on more efficient comminution, beneficiation, and final recovery. This change in scene has been brought about by: ? The introduction, rapid development, and maturation of multiple comminution, sorting, and recovery technologies ? The need to adapt to a new standard of project approach post the commodity super-cycle phase, where optimizing existing operations and developing scalable, ?fit for purpose? new mines are fast becoming the norm in diamond processing plants in both primary and alluvial operations ? The quest for energy efficiency and lower labour costs ? More remote and inaccessible reserves (under lakes, tops of mountains etc.). This paper serves to identify some technology advances and demonstrates how these could be considered as replacements for or in combination with conventional technologies to arrive at an optimum techno-economic solution. To name a few applications/technologies: ? Comminution: conventional cone crusher, modified/specialized cone crusher, and the high-pressure grinding roll (HPGR). Although significant advances have been made in recent years, this paper only briefly covers comminution within the beneficiation circuit design ? Waste sorting: NIR (near-infrared) sorting, optical (colour) sorting, XRF (X-ray fluorescence) ? Primary concentration by combining dense media separation (DMS) with either XRT (X-ray transmissive), pulsed X-ray, jigs, or pan plants depending on the application, scale, and economics ? Final recovery of diamonds with either conventional X-ray technology, pulsed X-ray technology, or XRT. From recent studies, it can be concluded that there is no longer a standard solution, but rather the ?right? or appropriate solution. Through combining a sound knowledge of the ore source (ore dressing studies or onmine data gathering) and leveraging off the advances in technologies, one is able, through trade-off studies, to arrive at the ultimate techno-economic configuration, the ?right? solution. Emphasis is placed on maximizing diamond recoveries through appropriate technology selection and minimizing the associated costs in an effort to de-bottleneck or improve efficiencies of existing diamond processing plants, or to arrive at the ideal new diamond process plant design..

Jan 1, 2014

Council and Standing Committees - 1981/82 President: G. Y. Nisbet. Senior Vice-President: Prof. A. N. Brown. Junior Vice-President: Prof. R. P. King. Honorary Treasurer: Prof. D. G. Krige. Immediate Past President: Dr P. R. Joehens. Members of Council: B. C. Alberts, J. D. Austin, P. T. Fewell, C. E. Fivaz, J. J. Geldenhuys, Dr A. K. Haines, P. N. Harris, H. E. James, C. G. Knobbs, Dr B. K. Love¬day, Dr J. Lurie, C. S. MacPhail, D. G. Malan, J. C. Mostert, G. C. Thompson, Dr H. Wagner. Chairman, Witbank/Middelburg Branch: B. Rohrmann. Chairman, Orange Free State/Klerksdorp Branch: K. F. W. Eick. Chairman, Materials Engineering Specialist Division: G. Pienaar. Past Presidents serving on Council: Dr M. G. Atmore, H. Britten, Prof. D. D. Howat, Dr J. P. Hugo, D. G. Maxwell, Prof. R. P. Plewman, Dr R. E. Robinson, Prof. M. D. G. Salamon, P. W. J. van Rensburg, D. A. Viljoen, P. A. von Wielligh. Standing Committee Chairmen: Constitution, Rules and Policy, Dr P. R. Jochens; Membership, Prof. R. P. King; Training, Career Guidance and Education, P. A. von Wielligh; Journal, Prof. A. N. Brown; Monograph Series, D. G. Malan; Technical Programme - Metallurgy, C. E. Fivaz; Technical Programme - Mining, P. N. Harris; SAIMM Schools - Metallurgy, Dr B. K. Loveday; SAIMM Schools - Mining, J. D. Austin; 1982 CMMI Congress, Dr M. G. Atmore; Awards, Dr P. R. Jochens; Adjudication, Dr P. R. Joehens; Phoenix National Committee, Dr M. G. Atmore; Excursions, J. C. Mostert; Mines and Works, Prof. A. N. Brown; World Mining Congress - National Committee, Prof. R. P. Plewman.

Jan 1, 1982

Council and Standing Committees - 1983/84 President: Prof. R.P. King Vice Presidents: J.D. Austin and H.E. James Honorary Treasurer: Prof. D.G. Krige Immediate Past President: Prof A.N. Brown Members of Council: B.C. Alberts, Prof. S. Budavari, N.J. Devine, Dr C.J. Fauconnier, P.T. Fewell, C. E. Fivaz, J. S. Freer, Prof. G.G. Garrett, J.J. Geldenhuys, Dr A.K. Haines, Dr B.K. Loveday, G. Pienaar, B.E. Protheroe, Dr O.K.H. Steffen, G.C. Thompson, Dr H. Wagner, Dr P.T. Wedepohl Chairman, Witbank/Middelburg Branch: H.C. van Zyl Chairman, Orange Free State/Klerksdorp Branch: D.A. Parfitt Past Presidents Serving on Council: Dr M.G. Atmore, Dr J.P. Hugo, Dr P.R. Jochens, Prof. R.P. Plewman, G.Y. Nisbet, Dr R.E. Robinson, Prof. M.D.G. Salamon, P.W.J. van Rensburg, D.A. Viljoen, P.A. von Wielligh Standing Committee Chairmen: Adjudication, Prof. A.N. Brown; Awards, Prof. A.N. Brown; Banquets, J.S. Freer; Constitution, Rules and Policy, Prof. A.N. Brown; Excur¬sions, J.S. Freer; Journal, H.E. James; Membership, H.E. James; Phoenix National Committee, Dr M.G. Atmore; SAIMM School - Extractive Metallurgy, Dr A. K. Haines; SAIMM School - Mining, Dr H. Wagner; Special Publica¬tions, J.D. Austin; Technical Programme - Extractive Metallurgy, Dr B.K. Loveday; Technical Programme - Mining, G. C. Thompson; Technical Programme -Physical Metallurgy, G. Pienaar; Training, Career Guidance and Education, Dr M.G. Atmore; World Mining Congress - National Committee, Prof. R.P. Plewman; Working Group Physical Metallurgy, Prof. G.G. Garrett

Jan 1, 1984

By R. P. King

An Analytical Solution to the Batch comminution Equation R. P. King, Pr. Eng., B.Sc. (Eng.), M. Se. (Eng.), Ph.D. (Visitor). An analytical solution to the batch-grinding equation is presented in terms of the generalized hypergeometric series and the confluent hypergeometnc function. This solution is valid for selection functions that are describe~ piece-wise by functional forms of the type KOXB and by normalized breakage functions of the type B(x,x') = (x/x')x. These functional forms are sufficiently general to Include most practical cases. In particular, they can be used to describe selection functions that have a maximum.

By P. Horrell, K. Rhodes, G. Harrison, J. Dean, D. Sammons, M. Stander

Anglo Platinum have perceived a need to increase the rate of reef development both for new mechanised stoping technology and on conventional new developing mines. The Research and Development Division of Anglo Platinum therefore initiated an experimental reef raise project with a tunnel boring machine (TBM) at Bafokeng Rasimone Platinum Mine (BRPM). The scope of the trial was for the boring of a reef raise 340 metres in length on the Merensky Reef. The boring phase of the trial took place over six months and the average rate of penetration of the TBM was 0,47 metres/hour. TBM utilisation was 22%. The TBM used in the trial was a Jarva MK6 manufactured in 1972 and its design with its backup system was not considered to be an ideal machine for reef development. However it was the intention of the trial to prove the concept of developing with a TBM on reef. In this respect the trial was unequivocally a success. There were many problems and long delays did occur during the boring phase. Nevertheless there is every confidence that a new TBM can be designed specifically for this type of work that will achieve high rates of advance up to (say) 400metres/month and with a more flexible steering system in order to negotiate reef changes. It can therefore be expected that TBMs will be used in the future for reef development on South African platinum mines.

Sep 1, 2001

By E. J. Magri, A. Couble

Kriging estimates of geological resources are sometimes conditionally biased because the kriging plan contains too few samples. This may be done purposely in order to match the variance of the estimates to the true block dispersion variance. This work aims at evaluating the influence of conditional bias over the ultimate optimum pit design in relation to its shape, size and NPV (Net Present Value of profits). It has been restricted to two real case studies: a ‘carrot shaped’ gold porphyry in northern Greece and a manto-typeexotic copper deposit located in northern Chile. The methodology applied to each deposit consisted of generating a ‘real block model’ and four resource estimates by the use of conditional simulation and the application of four different kriging plans to the drillhole databases respectively. The estimation models vary in smoothness and conditional bias. Ultimate optimum pits were determined for the ‘real’ and the four different kriging models. Pit comparisons lead to the following conclusions: •In the worst case, conditional bias overestimated the project's NPV by 32% and 5% for the gold and copper deposits respectively. •The overestimation of high grades is more relevant than the underestimation of low grades. This resulted in a tonnage over-extraction of 148% and 1% for the gold and copper deposit respectively. This difference was attributable to the vastly different geometry of the deposits. •The smoothing effect of kriging, without or very little conditional bias, produced open pits that were different to the ‘true’ (ideal) ones and furthermore, underestimated the project's NPV by 10% and 6% for the gold and the copper deposits respectively. •Other factors that influence the optimum open pit design and to some extent control the effect of conditional bias are: the cut-off grade, the orebody geometry and distribution of grades within it and the amount of over-burden. Keywords: conditional bias, ultimate pit design

Jan 1, 2003

"Chairman: Dr DeV. HarrisRapporteur: Mr A.H. MunroPapers:Corporate exploration strategies by MacKenzie, B.W.The Engel Simulator and the search for uranium by Griffiths, J.C. and Singer, D.A.The Chairman opened the session by tracing the changes which have taken place in the exploration field since the days of the lone prospector who relied upon his individual skills and to a large extent on luck. The deposits which now remain to be discovered are better covered and are of lower grade. A much greater team effort, involving geoscientists and engineers, is required. The gamble is thus much greater -not only are the probabilities of failure still significant but the consequences are more severe. A recent Canadian survey indicated that expenditures of between two and nine million dollars on regional exploration programs are required to locate one significant deposit.The Chairman went on to say that these facts have led companies to regard exploration as another form of investment and to treat it accordingly. This had placed exploration in the context of corporate strategics and structures, which was the subject of the first paper of the session.In introducing his paper, Dr B. W. MacKenzie said that the paper suggested a decision framework for exploration planning. Initially the environment is analyzed to define observable and relevant economic characteristics. The terms of reference for exploration planning and the appropriate allocation of capital and skills are then established in the light of corporate objectives and growth alternatives. With the aid of this information and in the light of profit and corporate risk criteria, exploration strategies can be selected.Dr MacKenzie went on to say that the usefulness of the concept and criteria outlined in his paper depended critically upon three characteristics of any particular economic environment, namely, the return resulting from an economic discovery, the unit discovery Cost and the probability of making an economic discovery. He then showed by means of a case history relative to the Canadian Shield and Cordilleran areas that these three characteristics could, in fact, be evaluated for regions with reasonable histories of mineral activity.The first contributor to the discussion of the paper, Mr Alfred Weiss, mentioned that his group had been involved in exploration modelling for some ten years and were thus particularly interested in the paper. He went on to say that they had experienced greatest difficulty with reconnaissance programs and that he sensed that these difficulties were also present with the methodology which had been outlined. Mr Weiss asked Dr MacKenzie how he would deal with such situations when no information was available but where there was the potential for both exploration and discovery. Dr Mackenzie agreed that the lack of information was a very severe limitation and said that at the present time his methodology probably did not provide a basis for breaking down the broad geological regions he considered into areas for further assessment."

Jan 1, 2014

The January General Meeting was held at The Moth Hall, Witbank, on Thursday, 30th January, 1969. Mr C. G. Sowry (Chairman of the Witbank/Middelburg Branch) was in the chair. There were also present: Fourteen Members: Messrs A. Bain, A. W. L. Brereton, J. Meintjes, G. Langton, A. C. Hofmyer, J. H. Moore, T. S. Wilmot, B. F. van der Merwe, H. A. Williams, O. T. Wright, J. E. van Aswegen, P. J. Beukes, I. Botha. Six Associate Members: Messrs B. T. Hosking, R. E. Powell, J. B. Cornish, R. Ladner, W. Weber, P. J. Muller. Two Affiliates: Messrs P. B. Cass, W. K. C. Bremer. Nine Visitors. Apologies were received from Messrs G. R. Canny, E. J. Jackson. MINUTES OF THE PREVIOUS GENERAL MEETING It was proposed and accepted that these be taken as read. Proposer, J. Meintjies; seconded, A. W. L. Brereton. 75TH ANNIVERSARY CELEBRATIONS OF THE S.A.I.M.M. The Chairman reminded members of the functions arranged to mark this occasion. It was also mentioned that members desirous of forming parties to travel to Johannesburg should either make arrangements amongst themselves or inform the Secretary who would assist in arrangements. PAPER FOR PRESENTATION The Chairman then called upon Mr S. Selmer-Olsen to present his paper, 'Lectures on electro-smelting of ferro-alloys'. After Mr S. Selmer-Olsen had presented his paper, he answered questions arising from contributions from the floor. The Chairman then thanked Mr S. Selmer-Olsen for presenting his paper. CONTRIBUTIONS TO PREVIOUS PAPERS Contributions to the paper 'Photo-electric readings. Their significance for dust control on collieries,' presented by Messrs G. H. J. Kitson (Member) and Y. J. F. Haven (Visitor), were read by Messrs A. Bain and A. W. L. Brereton.