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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

Notices EIGHTH WORLD MINING CONGRESS The Eighth World Mining Congress will be held in Lima, Peru, from 3rd to 8th November, 1974. The theme of the Congress is 'Prognosis of mining development up to the year 2000', with the following subthemes: INF ACON 74 Readers are reminded of the International Ferro-alloys Congress being organized by the National Institute for Metallurgy, in conjunction with the Ferro Alloy Producers' Association of South Africa and the South African Institute of Mining and Metallurgy.

In mid-1984, SAIMM reached an agreement with the South African Region of what is now the Institute of Metals to combine the physical-metallurgical activities of the two organizations. This was the outcome of several years of informal collaboration, and followed the recognition in 1982 by the SAIMM Council that applied physical metallurgy had grown in importance to South African industry and should have a place alongside the two areas already well-established for SAIMM commitment and support-mining and extractive metallurgy.

Jan 1, 1986

By S. Budavari

On the one-hundredth anniversary of the founding of the South African School of Mines, this paper presents a historical review of the tertiary mining education carried out by the School of Mines in Kimberley and the subsequent institutions in Johannesburg. In addition to recording and evaluating a century of mining education, it describes the current activities of the Department of Mining Engineering at the University of the Witwatersrand, which is believed to be the natural successor to the School of Mines. The comparison of earlier and contemporary academic mining activities reflects a gradual transition from the educational philosophy and objectives of a school of mines to those of a modem university department. In the conclusions, some aspects of the educational effort expended during the past hundred years are briefly highlighted.

Jan 1, 1996

By A. Cambitsis

We show that the prioritization of business improvement and performance management decisions may be significantly improved by taking into account the systemic effects of changes made in a single process area. To do so we build a model of a mining value chain, taking into account consequential downtime that arises from downstream and upstream starvation and choking effects of each activity. Introducing the concept of internal capacity, this approach yields insight into the relative importance of key metrics such as loading and hauling rates. We suggest that a holistic view of this type should be a core component of business improvement and performance management decisions. Keywords value driver trees, production constraints, throughput analysis, capacity analysis, TOC (Theory of Constraints), activity interdependencies, unit cost reduction.

Oct 1, 2013

The Canadian Institute of Mining and Metallurgy. Milling practice in Canada. CIM Special Volume 16. 1978. The purpose of this volume is to up-date The Milling of Canadian Ores, which describes Canadian mineral. processing plants and gives other metallurgical information, and was published by the Sixth Commonwealth Mining and Metallurgical Congress in 1957. NIM reports Report no. 1874 Activation analysis and classification to soune of samples from the Kimberley Reef conglomerates. (10th Mar., 1977; released Jun. 1978). Report no. 1926 The analysis of anode sludges by X-ray-fluorescence spectrometry. (5th Jun., 1978). Report no. 1936 The analysis of mineralogical and metallurgical materials. A guide to the analytical techniques and instrumentation available at the National Institute for Metallurgy. Report no. 1959 The slag-metal equilibrium, and the activities of slag and metal components in the production of high-carbon ferromanganese. (15th May, 1978). Report no. 1965 Analyses, by several laboratories, of three ferromanganese slags. (22nd May, 1978). Report no. 1968 The influence of carbonaceous reducing agents on the rate of reduction of representative manganese and chromium ores. (28th May, 1978). Company Affiliates Guide To The Preparation Of Papers for Publication In The Journal Of The South African Institute Of Mining And Metallurgy The following notes have been compiled to assist authors in the preparation of papers for presentation to the Institute and for publication in the Journal.

Jan 1, 1979

By Q. G. Reynolds

The dual-electrode DC arc furnace, an alternative design using an anode and cathode electrode instead of a hearth anode, was studied at small scale using computational modelling methods. Particular attention was paid to the effect of two key design variables, the arc length and the electrode separation, on the furnace behaviour. It was found that reducing the arc length to brush arc conditions was a valid means of overcoming several of the limitations of the dual-electrode design, namely high voltages and arc deflection.

Jan 1, 2012

By R. Meyjes, P. Davies

Keywords: Pyrometallurgy, furnace, smelter, engineering company Metix is a private smelter engineering company wholly owned by its management. Its main lines of business in the ferro-alloy industry being: - turnkey smelter projects (LSTK) - engineering, project, and construction management projects (EPCM) - specialised furnace equipment comprising: ? complete electrode columns, including forged copper pressure rings and contact shoes, as well as fail-safe slipping devices ? water-cooled roofs ? bus-tube systems ? feed systems ? cooling systems ? linings ? off-gas systems ? tap-hole drills & clay guns - furnace power supply systems - ore agglomeration & sinter plants - feasibility studies & due diligence reports - technical consulting for investment banks - project procurement & cost control Metix management experience includes around 130 combined years of contacts and experience in the South African smelter industries. Over 30 furnaces have been built, for processes including FeCr (high, medium, and low carbon), FeSi, FeMn (high and medium carbon), SiMn (ultra low carbon), Si metal, and FeV.

Jan 1, 2006

By A. Ball

This paper addresses the need for a unifying model that will permit the selection and design of optimum materials for a given wear situation. With this objective in view, the characteristics of the various forms of abrasive, adhesive, and erosive wear are described in terms of localized stress, strain, strain rate, and frictional heating. The measured performance of a variety of metallic, ceramic, and polymeric materials and coated or surface treated materials are described briefly. These results were obtained under conditions of dry-particle abrasion, abrasion in conjunction with corrosion, cavitation erosion in liquids, erosion by particles in low- and high-velocity gas streams, and erosion by particles in a liquid stream. Electron microscopy was used extensively, together with microhardness profiles, in the determination of the modes of material detachment and the underlying deformations and structural changes. As a result of the experimental work, a model based upon a critical strain to microfracture is presented. The microstructural features and materials properties that determine wear resistance are discussed.

Jan 1, 1986

By J. R. de Wet

The behaviour of mild steel in aqueous cyanide solutions similar to caustic cyanide elution solutions was investigated at high temperature in electrochemical experiments. The anodic polarization diagrams of mild steel indicated that steel may undergo active dissolution under these conditions. The rare occurrence of gold plating in practice is the result of the limiting of the anodic dissolution of the steel by the presence of a passive layer on the steel. This passive layer is stable only in a certain potential range, and the free corrosion potential attained determines whether the steel will be passive or active. For conditions typical of elution columns, several corrosion potentials are possible, depending primarily on the initial condition of the steel and the concentration of oxygen in the solution. If these conditions result in the formation of a passive layer on the steel, changes in concentration and temperature will not necessarily result in plating since the layer may exist in a metastable form.

Jan 1, 1993

By deur R. R. Mears

The expected curtailment of activities within the gold-mining industry by the closure of the more marginal mines, and the shortening of the life of the industry as a whole as a result of rising costs and/or an uncertain gold price, are factors that are bound to harm the South African economy in a number of ways. The industry has no option but to regard the gold price, which is determined on the world market, as a given quantity. The remaining ore reserves al tend to be of a lower grade and/or to be found at greater depth. Therefore tighter control of working costs would seem to be almost the only option open to the industry. Working costs can be divided into two broad categories: costs emanating from the environmental characteristics of the orebody, and costs emanating from the general inflationary environment in which the industry has to purchase its inputs. Working costs stemming from the physical environment also fall into two categories: those relating to the grade of the orebody, and those resulting from working at increasing depth and temperature, together with the need to pump increasing quantities of water. The industry is both capital- and labour-intensive in absolute terms, since it requires large inputs of labour as well as of capital. It is limited in its scope to adjust its production function by becoming more labour- or more capital intensive, and is dependent on a large labour force, which cannot easily be replaced by capital inputs. On the other hand, large amounts of capital are required for investment in shafts, development, machinery, and equipment. Since the early seventies, the working costs of the South African gold-mining industry have increased at an annual rate that was significantly higher than the general rate of inflation. This rapid rise in working costs has caused some mines to find themselves in a difficult profit position. At times, the gold-mining industry has even been compelled to restructure its cost/revenue relationship rather fundamentally by revising the grade of ore worked sharply upwards or downwards, as the case may be. The rise in the gold price since 1972 has made it possible for the industry to introduce significant changes in its Black wage policy. The main aim was to increase the permanency of the Black labour force and to encourage local Black workers to join the industry. At the same time, significant increases were also experienced in the cost of machinery and stores, as well as of capital, mainly as a result of inflation. In the study on which this paper is based, the author attempted to measure the influence of environmental factors on working costs, using the physical consumption of electricity as a criterion for measurement. He found that the usefulness of this criterion in relation to factors such as depth, temperature, and water quantities pumped was invariably more than neutralized by the effects of greater productivity and economies of scale. The effects of these environmental factors on the working costs of the industry could therefore not be determined to any degree of accuracy. It seems that good progress is being made with the development of capital-intensive forms of technology aimed at coping with rapidly rising working costs and other effects of increasing depth. Techniques are also being developed to improve rock-cutting procedures and to eliminate the use of explosives in order to introduce a continuous mining process. On the whole, the gold-mining industry seems to be more sensitive to general inflationary pressures than to the cost effects that are associated with depth, temperature, and water quantities pumped. Greater control is possible over physical environmental factors such as the grade of ore mined, temperature, rate and nature of development of a mine, and adaptation of the daily working cycle to a continuous mining process. Wolfe and others hold the view that the industry will lose control over labour costs as a result of the 'sharp increase in wages and the growth of Black trade unions. However, the use of more capital-intensive technology will allow the industry to reduce its labour force, and a smaller, better-trained, and more permanent labour force will enable the industry to cope with the increasingly difficult physical environment and higher wages.

Jan 1, 1987

Dr T. F. Muller (Honorary President): "Mr President, gentlemen. May I congratulate the Institute on its 75th birthday, and your President on his comprehensive review of the Institute's 75 years. It is an interesting commentary on the affairs of the Institute that your President should refer to a speech made by a founder member 25 years ago on the occasion of your 50th Anniversary and then say there is no need to repeat what was given there, but that he would confine his remarks to bringing the Institute's history up to date. To me this suggests a remarkable continuity of thought and ideals-a welcome island of stability in an ever-changing world. One can somehow picture another future President, perhaps one of the younger and tougher members here today, doing the same thing in 25 years when you celebrate your centenary-and again someone doing the same in the year 2094 when your Institute is 200 years old! I hope they will recognise their debt to the early pioneers of the Institute gathered here today. In any event, this review of the fine achievements of the past 75 years is certain of an honoured place in the annals of the society. Here is a record of the onward march of technology in South Africa and a tribute to a long line of mining engineers, of chemists, metallurgists and geologists who made a greater contribution to the well-being and the prosperity of South Africans than South Africans generally are aware. Your Institute started off as a 'gold and cyanide club', peopled largely by chemists and metallurgists who made a signal contribution to the industry from the earliest times. Despite the addition to their ranks of ever-growing numbers of mining engineers, the metallurgist members have continued to make notable contributions. One recalls, for example, the manner in which they rose to the occasion to resolve the problems associated with the establishment of the uranium industry in this country. The creation of a major industry based on the existence of low grade uranium ores in the conglomerate reefs of our low grade goldfields is a classic example of the manner in which a new large industry can be rapidly created through the combined endeavours of all concerned. I noted with pleasure your remark, Mr President, that members of the Institute would like to keep up to date with recent progress in nuclear fuel matters and that members should be given the opportunity to study developments in their journal. I am sure that the National Institute of Metallurgy which conducts fuel research on behalf of the Atomic Energy Board and of the Uranium industry, and NUFCOR, which co-ordinates the uranium research programme, would be glad to co-operate if invited by the Institute to make periodical contributions to its journal. You have referred to the building up of our research organization and its dynamic approach to mining problems. I understand that the expenditure of the mineral industries on research exceeds one-third of the entire research expenditure of the private sector. South Africa is in the forefront of mining development and the focus of world attention is on the achievements of our scientists and mining engineers. We can look forward to continued advances in mining technology based on their vision and expertise. I share your disappointment, Mr President, that the Base Metals Division has ceased to exist; and that there is a resultant dearth of papers offered to the Institute on these important sections of mining and metallurgy. We are seeing some remarkable developments in the mining and beneficiation of base minerals, and it is in this area that I see the greatest potential for future expansion. If we can grasp the opportunities

By W. F. A. T. Meihack

The scope of this paper is confined to gas-fluidized beds in pyrometalurgical applications. After considering the general characteristics of these fluidized beds, the author deals with their potential applications, using the following processes, which are currently under investigation, as examples: pretreatment of chromite, prereduction of manganese-ore and iron-ore fines, roasting and prereduction of ilmenite, and roasting and pyrolysis of gold-bearing pyrite. He concludes that fluidized beds are potentially of great benefit to the metallurgical industry, although much developmental work remains to be done.

Jan 1, 1986

By P. C. Schutte, N. B. Strydom, A. J. Kielblock

Three groups of unacclimatized men were subjected to five-day climatic-room procedures at wet-bulb temperatures of 29,30, and 31 C respectively. The findings indicated that individuals reach a satisfactory level of heat acclimatization for work in environmental temperature conforming to those at which they were acclimatized. It is, therefore, superfluous to acclimatize men at wet-bulb temperatures that exceed those at which they are destined to work. These methods of acclimatization can be linked advantageously to heat-tolerance testing at mines with suitable underground temperatures.

Jan 1, 1983

By Y. Hwang, C Kang

To understand the effect of thermal loading from HLW on the groundwater flow nearby, the coupling of TH in an equivalent porous medium is studied. Results indicate that under given conditions the alteration of groundwater flow by decay heat is localized phenomena. More comprehensive studies are underway for THM coupling. Zum Verstandnis fur die Wirkung der thermischen Belastung von HLW in der Nahe von Grundwasserstrom, ist die Verbindung von TH in den entsprechenden porigen Medium erarbeitet. Die Ergebnisse zeigen, dass unter vorgegebenen Bedingungen die Anderung von Grundwasserstrom durch Zerfallwarme lokalisiert wird. Zusatzliche umfassende Arbeiten sind fur die THM Kupplung auf dem Wege. Pour comprendre l'effet du chargement thermique de HLW sur l'écoulement d'eaux souterraines tout près, l'accouplement du TH dans un milieu poreux équivalent est étudié. Les résultats indiquent que dans des conditions données le changement d'écoulement d'eaux souterraines par la chaleur d'affaiblissement est des phénomènes localisés. Des études plus complètes sont en cours pour l'accouplement de THM.

Jan 1, 2003

By B. J. Ralph, I. J. Corrans, B. Harris

In the first section, a brief background to the practical and theoretical aspects of bacterial leaching is presented. Descriptions are given of present and potential methods for exploiting bacterial leaching in metal-winning. In the second section, the results of recent research are presented. The aim of this work was to obtain a greater understanding of the mechanism of bacterial leaching of sulphide minerals. Bacteria were observed to catalyse leaching reactions by oxidising ferrous ions to ferric ions, by removing protective films at the mineral surface and by depolarising cathodic areas.

By O. Korhonen, T. Leskinen

The use of large OK-16 flotation machines at the concentrators of Outokumpu Oy by o. KORHONEN and T. LESKINEN(Visitors) The development ofthe OK-16 flotation machine is described briefly, and an account is given of its use at various concentration plants in Finland. The benefits arising from the use of larger flotation machines are listed, and the technical specification of the OK-16 machine is detailed in an appendix.

Jan 6, 1976

By A. J. Barrett

Backfilling at Vaal Reefs during the experimental phase has been carried out using cyclone-separated tailings which are transported underground hydraulically by means of a borehole. The selected tailings are piped from the borehole to the stope and then, after the addition of a flocculant, deposited in place via single or multiple nozzles. The successful performance of the backfill/stope system relies not only on the actual quality of the placed material, but also on the effective operation of stope filling. The success of stope filling relates to the complex, time- dependent interaction of backfill, stope and barricade materials, and the transport and placement procedures used. A comprehensive laboratory testing programme was carried out on backfill materials at Vaal Reefs in conjunction with the experimental stope- filling operation. The range of testing techniques corresponds to the requirements of each stage of the backfilling process. Where necessary, new or alternative techniques were sought during the course of the experiment to satisfy and facilitate better understanding of the different processes. These techniques comprise both routine quality control testing and research-oriented testing. The laboratory testing techniques appropriate to each stage of the backfill process are briefly discussed. This paper presents the main conclusions of the study and identifies areas for further research.

Jan 1, 1988

By deur J. V. D. M. Grimes

Sishen Iron Ore Mine is one of the largest open-pit mines in the world, and loading and hauling constitutes one of the major cost items on the mine. Because high productivity in loading and hauling results in large financial benefits, the following projects to improve productivity were implemented at Sishen: - a computerized truck-allocation system, - an overhead power-supply system for the dieselelectric driven rear-dump trucks, - an in-pit crusher and a belt-conveyor system. This paper concentrates on the truck-allocation system, with special reference to the improved productivity of loading and hauling resulting from the implementation of this system.

Jan 1, 1984

Dr H. J. van Eck (Honorary Life Member): "Mr President, I regard it as a signal honour that I was invited to address the South African Institute of Mining and Metallurgy on its 75th Anniversary. I also wish to add my congratulations and good wishes to the many you have already received on this memorable occasion. Seventy-five years is indeed a good age and the achievements of your Institute certainly justify this special celebration. South Africa owes her present prosperity largely to the technological ability and determination of her own people. Members of the Institute contributed in large measure to this great development of our country and through the years have upheld their high reputation for scientific integrity, dynamic enterprise and dedicated service. It was their knowledge which provided the key to unlocking the mineral wealth which lay dormant for countless ages. The history of world mining dates back many centuries. We know of the mercury mines of Spain, the tin mines of Cornwall and the zinc mines of Poland, but it was not until colonization of the western hemisphere started in about 1500 that mining of any consequence began in North America. It is true that the peoples of South America and Mexico had accumulated wealth out of gold and silver, but industrialized mining was not a feature of these agrarian cultures. The mining wealth that eventually developed in North America was based on advances in the technology of processing minerals and served as an incentive to people in other new countries. Big mines were opened elsewhere in the world. From Canada, Mexico, Venezuela, Brazil, Peru, Chile, Bolivia, Rhodesia, Australia, Burma and India, to name but a few, there has been a steadily increasing production of an expanding range of minerals and metals. By the middle of the 20th century the trend was to increase the production and use of such comparatively uncommon metals as cobalt, nickel, titanium, and others, and a great mining rush started to search for, and develop, the deposits of uranium, and related radio-active minerals. It is worth pausing a few minutes to reflect that most of early mining was based on the recovery of virgin metals like gold and silver or easily treated high grade ores of copper, tin and zinc. Today, much of this type of mining would be regarded as picking the eyes out of the mine. With the development of improved ore separating, ore concentration and recovery processes, we developed into bulk mining and bulk treatment and in South Africa we have some very big mines, also outside the gold mining industry at Phalaborwa, for instance. Mining techniques are applied which compare with the best in the world. These large mines could only develop because of the perfection of new concentrating techniques and, of course, because of the development of markets. We have mentioned nickel and cobalt. These names were given to those mischievous mining sprites called nickels and kobolds to whom the suspicious miners ascribed their inability to smelt copper from copper nickel or arsenious copper ores. In South Africa, the presence of minerals was known to the modern Western world as far back as 1497 when Vasco da Gama found the native 'strandlopers' at the St. Helena Bay wearing copper rings. In 1669, after the British East India Company had formed their settlement, they employed miners and assayers in prospecting for minerals and in 1685 found traces of copper in the copper mountain of Namaqualand where some 170 years later a rich deposit of copper was to be opened up. This deposit also had a chequered