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By Q. P. Campbell

Activated carbons used in the precious metals extraction industry are characterized by large internal surface areas and a great affinity for metal ions. The purpose of this research is to prepare activated carbon from a South African bituminous coal by physical activation that is suitable and cost-effective for use in the extraction of metals. The quality of the coal-based activated carbon may not prove to be as good as activated carbon produced from other traditional sources, but the production costs involved may make South African coal a feasible alternative feedstock. The activated carbons produced were characterized by Brunauer, Emmett, and Teller (BET) surface area, activated carbon pH, and phenol adsorption studies and the results compared to the results from a commercially available activated carbon, Norit RO 0.8 (control sample). Bituminous coals from various sources including Witbank Seam 4 and Free State coal were used in this study. The preparation method chosen was physical activation using superheated steam. The effects of process variables such as activation time (1-3 h) and temperature (600-800°C) were studied in order to optimize those parameters. The activated carbon surface area was characterized by means of nitrogen adsorption isotherms at 77K. BET surface area analysis showed that Witbank Seam 4 coal activated at a temperature of 800°C and activation time of 3 hours resulted in a surface area of 340 m2/g. Quality control of each sample was performed by measuring the pH of a known amount of the prepared activated carbon in distilled water over time. Results showed that the pH of some of the prepared activated carbons reached a value of 11. Phenol adsorption results for the different activated carbons prepared corresponded well to the results obtained for the Norit RO 0.8 activated carbon sample.

Jan 1, 2012

Corosion technology: An information source book, by Judith Ann Douvile. Taylor & Francis, 1989. 188 pp. £32. Stainless steel buyers guide 1990. Southern Africa Stainless Steel Development Association (P.O. Box 4479, Rivonia, 2128), 1990. Free. Fatigue and stress of engineering materials and structures, edited by H.P. Lieurade. ITT International (40 Promenade Marx-Dormoy, 93460 Gournay-sur- Marne, France), 368 pp. US$ 109. Titanium and aluminium, edited by P.A. Coulon. ITT International (40 Promenade Marx-Dormoy, 93460 Gournay-sur-Marne, France), 200 pp. US$ 80. Engineering applications of stochastic processes. Theory, problems and solutions, by A. Zayezdny, D. Wulich, and D. Tabak. Chichester, John Wiley, 1989. 525 pp. £54.50. Metal behaviour and surface engineering, edited by S. Curioni, B. Waterhouse, and D. Kirk. ITT International (40 Promenade Marx-Dormoy, 93460 Gournaysur- Marne, France), 413 pp. US$ 109. Fuzzy control and fuzzy systems, by W. Pedrycz. Chichester, John Wiley, 1989. 272 pp. £37.50. CILO (carbon-in-leach with oxygen) cost study, by Minproc Engineers (USA). Free.

Jan 1, 1990

By J. Gilliland

The Grootegeluk coal-beneficiation plant was erected in the Waterberg coalfield, near Ellisras in the Transvaal, to supply Iscor's steelworks with a predetermined tonnage of coking coal in accordance with strict quality requirements. This plant has to handle a high tonnage of raw coal, which is not easy to beneficiate, in order to produce 1,82 X IQ6t of coal. Extensive tests were conducted on borehole cores and a mass sample of coal obtained from the area. These tests were carried out on a laboratory and pilot-plant scale, and were aimed at the establishment of the most effective beneficiation methods and the choice of suitable equipment. This led to the completion of a full set of design and manufacturing drawings that resulted in the project approach . described in this paper.

Jan 1, 1982

Financial Times Mining International Year Book 1979. London, The Financial Times Limited, 1979. 712 pp. Price: airmail, U .S. $60,00; surface mail, U .S. $42,00. International Wrought Copper Council. Glossary of terms applicable to wrought products in copper and copper alloys. London, the Council (6 Bathurst Street, Sussex Square, London W2 2SD), 1978. 170 pp. 80 Swiss francs (approximately £25). Council of Mining and Metallurgical Institutions At a meeting of the Council of Commonwealth Mining and Metallurgical Institutions held on 15th January, 1979, it was unanimously agreed that the name of the Council should be changed.. Assaying and analytical techniques This year sees the Diamond Jubilee of the South African Institute of Assayers and Analysts, which held its first meeting on the 3rd of May, 1919.

Jan 1, 1979

NIM reports Report no. 1970 List of unrestricted NIM publications issued from 1966 to 1978. (30th Jun., 1978). Report no. 1976 The preparation and certification of two samples of chromium ore. (9th Sep., 1978). Report no. 1982 The resistivity of mixtures of Mamatwan manganese ore and reducing agents. (31st Aug., 1978). Report no. 1984 Commissioning of the AEI MS702 mass spectrometer. 31st Aug., 1978). Metallurgical slags The Basic Science Section of the Canadian Institute of Mining and Metallurgy is sponsoring an International Symposium on Metallurgical Slags, which is to be held in Halifax, Nova Scotia, during 24th to 28th August, 1980. Mining machinery An international conference on mining machinery is to be held in Brisbane, Australia, from 2nd to 6th July, 1979.

Jan 1, 1979

By O. K. H. Sheff

An editorial in the April 1990 edition of Mining Magazine is worth a wider audience in South Africa, particularly as the SAIMM enters its own centenary decade and the process of change in the minerals industry world-wide makes increasing demands on the professionalism of its leaders. The editorial considers the changing status of engineers, who up to the 1880s had been held in high regard by society. Alumina and bauxite Economists forecast a slower economic growth rate in 1990, but expect continued increase in demand for aluminum at a 3 per cent annual rate during the decade. Structural and numerical analysis Struceng & Femcad (structural analysis and finiteelement method) is a conference and exhibition that is to be held in Grenoble (France) on 17th and 18th October, 1990. It is sponsored by the Institute for Industrial Technology Transfer (ITT-International).

Jan 1, 1990

By N. C. Joughin

Potential for the mechanization of stoping in gold mines by N. C. JOUGHIN B.Sc. Eng., Ph.D. (Rand) (Member) The basic requirements for stoping machines are identified first by examination of the mining rates and productivities attained in conventional stoping, and then by examination of a series of problem areas associated with the shape of the reefs, rockbreaking, rockhandling, and the support and design of the machines. Some of the more important machines being developed are described briefly, and their principal features are compared with the basic requirements identified in the first part of the paper. An estimate of the potential demand for the different types of machines is given.

Jan 1, 1976

By G. R. Marchant, B. K. Loveday

A mathematical model has been developed for flotation circuit simulation. This model was designed to investigate the effect of varying the circulating loads and to determine whether an improvement in overall efficiency could be gained by a size separation prior to flotation. Model parameters were obtained by regression to plant data. Highly correlated parameters in the model were combined to reduce the number of parameters so that the need for excessive data gathering was eliminated. Mass balance smoothing was used to obtain a consistent data set for regression. The results of the simulation indicate that for the same grade of concentrate, an increase in copper recovery of 0.6 per cent may be possible by increasing the circulating loads. The results of the simulation also indicated that recleaning of the plus 200-mesh material may be beneficial.

By J. Meintjes

The measures taken by Rand Carbide Limited from the 1950s to 1976 to control dust emission from the electric furnaces at its Witbank factory are described. A new design of furnace for calcium carbide followed by a dry-fabric filtration plant for the furnace gases was not successful in arresting the dust. A 131 m chimney commissioned in 1968 effectively dispersed the dust-laden gases from both carbide and ferrosilicon production and so brought considerable alleviation. In 1974 a bag-filter dust-collecting plant was successfully commissioned on a 6 MV.A carbide furnace, and this was followed in 1976 by a bag-filter plant on a 46,5 MV.A ferrosilicon furnace. The company has spent considerable effort and money over two decades in trying to combat dust emission, but eventual success had to await technological development.

Jan 1, 1978

By P. A. Laxen, P. J. van Staden

In situ leaching tests with thiourea as the lixiviant were caried out in two worked-out stopes at the No. 6 shaft at Rand Leases Gold Mining Company. Dissolution rates of 0,9 and 0,7 9 of gold per week per 100 m2 of footwal area were achieved. A major disadvantage of the method seems to be the slow rate of dissolution of the gold, which is probably caused by poor contact and slow mass transfer between the lixiviant and the gold surfaces. Under full-scale application, the loss of lixiviant by leakage could also be a very important factor. Furthermore, the oxidation products of thiourea may 'poison' the activated carbon that is used for the recovery of the gold. The method may therefore be economically viable only in stopes that contain high values of residual gold.

Jan 1, 1989

By M. J. U. T. Van Wijngaarden

SYNOPSIS The corrosion characteristics of a new steel, 14Cr, which is a modification of the well-known 3CR12, in aqueous sulphate solution were studied through polarization diagrams and a computer analysis based on the polarization¬resistance technique. It was found that the corrosion rate of 14Cr steel is independent of pH for pH values above 6, but, below a pH value of 4, the corrosion rate increases sharply with decreasing pH. In air-saturated solutions of neutral and mildly alkaline pH, the corrosion rate is approximately 60 µm per year. The 14Cr steel shows a twentyfold improvement in corrosion resistance over that of 3CR12 in sulphate solutions at pH 2,0. This is considered to be due to the beneficial effect of its higher chromium and nickel contents.

Jan 1, 1985

Visit to the Datsun Nissan Company's body pressing and assembly plant at Rosslyn, Pretoria, and the Claremont-Danville Tunnel on 27th February, 1970. The excursion arranged for the 27th February to the Datsun Nissan motor car assembly plant at Rosslyn, near Pretoria, in the morning and the Claremont-Danville tunnel in the afternoon was well supported by some 43 members. The visitors were met at the factory by Mr Rademeyer, the Industrial Relations Manager, and members of his staff and were taken to the artisan training centre for light refreshments. There is a well-equipped training section with an air-conditioned lecture hall; we were told that such training facilities were important because of the cosmopolitan nature of the artisan staff. The visitors were divided into small parties and taken to the tool die and jig-making section, which is perhaps the key department for a factory of this nature. There the many dies for the presses in the body pressing section, as well as the complicated jigs for body welding are made. The technique for making the castings for the dies is interesting. A polystyrene model of the casting is embedded in moulding sand. In a neighbouring foundry molten metal is pressed into the headers and burns away the polystyrene, which leaves no residue, and this exactly fills the space occupied by the model. This rough casting is then machined in large copying machines (costing as much as Rl80 000). An exact plastic model of the surface of the pressing required, set up in juxtaposition to this casting is traversed by a master stylus which operates the slave milling cutter, thereby machining the surface to close tolerances. The machined casting is cleaned up by hand and finally finished in large spotting machines, using a blue dye to show up high spots, to the fine degree of accuracy required. The body pressing section was next visited. There the large number of pressed parts which make up a vehicle body are pressed out of special deep drawing steel plate. Some of the largest presses were capable of applying a pressure of 1 200 tons and cost as much as Rl85 000 each. The visitors then followed through to the assembly section where jigs are used to hold together the many pressings, which are then spot welded into body frames. The frames go to an assembly line where they are finished to the stage for painting. The continuous crawl painting assembly line carries the frames through all the stages of prime coating with zinc phosphate sprayed on in a tunnel, followed by immersion of the lower parts in a priming bath, then drying and spray painting and baking in tunnels. The body frames, after painting, join another assembly line, where the doors, upholstery and many fittings are attached. After this stage the completed bodies are lowered onto and attached to the chassis units which are largely assembled from imported parts (engines, transmission units, etc.). From the end of the line the completed cars are driven off to the trial track and then pass through a tunnel with powerful water sprays to detect leaks in the body work. The proportion of locally made parts is just on 45 per cent. An interesting aspect of the assembly organization is that, of the 140 or 160 cars completed each day there may be included some of each of the Datsun model as well as some Renault and Alfa Romeo models models which are assembled by this company. The change from one model to another several times a day does not present any difficulty to the organization. Each section of the assembly plant 'buys' the units from the preceeding section and 'sells' to the succeeding section. This means that the responsibility of each section ends when the unit is sold to the next section. The cost of repairing any faults found subsequently is charged to the section where it is found, which puts a powerful emphasis on meticulous inspections between sections to safeguard their costs. After the tour the parties assembled at the lecture hall where a lavish cold buffet luncheon was provided by the company. After luncheon Mr A. R. C. Fowler, on behalf of the Institute, thanked the Managing Director, Mr W. J. Wilson and his staff for this most interesting and well organized visit. The party then left for the Claremont-Danville tunnel. The tunnel is being driven by General Mining Federale Kontrakteurs through the Daspoort Range, Pretoria, to link the suburbs of Danville, near Iscor, and Claremont, which at present can only be reached by a nine mile detour. It is estimated that some 6000 vehicles per day will use the tunnel. Before entering the tunnel a short talk was given by Mr Ross who is in charge of operations. He called on various officials and staff of the Consulting Engineering firm, Basil Read (Pty.) Ltd., to describe the tunnel and

THE BRITISH COUNCIL AWARDS 1971-1972 The British Council invites applications from permanent residents of the Republic of South Africa and South West Africa, for the following awards: SCHOLARSHIPS Scholarships are available to such permanent residents who hold university degrees or comparable professional qualifications. The scholarships are tenable for postgraduate study at universities and other educational establishments in Britain for the academic year of approximately ten months beginning 1st October, 1971. BURSARIES Bursaries are available to such permanent residents who hold university degrees or who, being already established in their professions or trades, hold other qualifications. The bursaries are tenable at British educational institutions or other suitable establishments in Britain for a course of training, study or research lasting not less than two months or more than six. The British Council may, at its discretion, bear the cost of single or return fares to Britain. The closing date for applications is 31st July, 1970. TRAVEL GRANTS Travel grants each of £300 are available in respect of journeys to Britain undertaken between 1st April, 1971 and 31st March, 1972 and are provided to facilitate visits to British universities by persons holding staff appointments or graduate research posts at South African universities. Visits must normally be of at least six months duration. The closing date for applications is 31st October, 1970. For further particulars and the relevant application forms please write stating the type of award for which you wish to apply to: The Cultural Attache, British Embassy, Pretoria. THE SECOND INTERNATIONAL CONFERENCE ON THE PROPERTIES OF LIQUID METALS Tokyo, September 1972 The Second International Conference on the Properties of Liquid Metals will be held under the auspices of The Japan Institute of Metals and The Physical Society of Japan from 3rd to 8th September, 1972 in Tokyo. The purpose of this conference is to continue and extend the efforts towards the objective of the First International Conference on the Properties of Liquid Metals at Brookhaven, 1966. The tentative Conference subjects presently planned are: Structure of Liquid Metals and Alloys; Atomic Transport Properties (Diffusion, Viscosity, etc.); Electronic States and Transport Properties; Thermodynamical Properties; Melting and Phase Transitions. Correspondence regarding the Conference and the request for the First Notice should be addressed to: Professor S. Takeuchi, Chairman of the Organizing Committee, The Research Institute for Iron, Steel and Other Metals, Tohoku University, Sendai, 980, Japan. PROCEEDINGS OF THE NINTH COMMONWEALTH MINING AND METALLURGICAL CONGRESS 1969 Volume 4 of the Proceedings of the Ninth Commonwealth Mining and Metallurgical Congress 1969- Physical and fabrication metallurgy-contains the 24 papers presented under this general heading at the Congress. Also included are discussion, authors' replies, name and subject indexes, and plenary addresses by Sir Val Duncan, O.B.E. and Sir Ronald L. Prain, O.B.E.

The Centenary Distinguished Lecture was held on Thursday, 24th March, 1994 at the Convention Centre of the Sandton Sun, Johannesburg at 20:00. Herewith the proceedings that followed. P.R. Janisch: The South African Institute of Mining and Metalurgy began life one hundred years ago tonight, and eight years (almost to the day) after the 1886 discovery of gold, which has impacted so profoundly on the course of events in our country since then. The Early Years That discovery was a mater of fortune, but not in the sense of the conventional prospector's lucky strike. Canny explorers, such as the Strubens, had been around for some years and, if George Harrison had not stumbled over the Main Reef when he did, someone else would surely have done so within months. The element of luck was that the gold-bearing rocks of the Witwatersrand actually lay exposed to sight. We now know that they are something of the order of 2,5 billion years old. Rocks of that age are usually covered by younger formations. In fact, the bulk of the Witwatersrand Basin is covered by lava, dolomite, and Karoo measures. What, one wonders, would our history have been had the Karoo, which stops at the Vaal, extended no more than 60 kilometres further north. Dr H. Scot-Russell A piece of advice attributed to Paul Kruger, the who was President of the South African Republic one hundred years ago, was the following: 'Seek from the past that which is good, and build on it for the future'. It is advice that can be applied universally and, whether deliberately or not, it must have motivated my predecessors when this Institute celebrated its 40th, 50th, and 75th birthdays. Those milestones were each marked by retrospectives, as Peter Janisch has so ably presented tonight on our hundredth anniversary. The parallels do not end there. We find ourselves in times no less daunting than those our predecessors. Next month will see the birth of a new kind of South Africa; so did May 1902, May 1919, and May 1948.

Jan 1, 1994

By S. L. Crouch

A. C. Dieringt The procedure described by Professor Crouch for the modelling of mining in faulted ground allows the elastic and inelastic deformation to occur simultaneously, that is, fault slip occurs while an element is being mined. The energy release rates (ERR) shown in Crouch's Fig. 10 are apparently calculated from his equation 9 using the i total deformation Din (see the upper load line of Fig. I) Refractories The institute of 'Gesteinsh iittenkunde' of the technical university at Aachen, the Refractories Research Institute at Bonn, and the Verein Deutscher Eisenshiittenleute (VDEh) at Diisseldorf are to hold the XXII International Refractory Colloquium on 27th and 28th September, 1979, at Aachen.

Jan 1, 1979

By F. L. D. Cloete

The following discussion relates to the paper by G. S. Hansford, C. D. Levy, and J. W. de Kock that appeared in the March 1976 issue of the Journal (vol. 76, no. 8, pp. 363-369) Competition for student members Each year the South African Institute of Mining and Metallurgy offers a prize (or prizes should the entries warrant it) of up to RI00 for the best paper or dissertation on a topic appropriate to the interests of the Institute. Engineering in South West Africa The SW A Engineering Profession Steering Committee was established on 4th April, 1977, its purpose being to formulate an Act covering the engineering profession in South West Africa.

Jan 1, 1978

By V. G. Pienaar, B. M. Mbiya, P. T. Slatter

[a constant b constant cc onstant c' constant D pipe diameter (m) Dshear shear diameter (m) E error function fth theoretical friction factor F function F' function K fluid consistency index (Pa sn) kv valve loss coefficient L pipe length (m) n flow behaviour index N number of data points ?P valve pressure drop (Pa) Q flow rate (m3/s) Re Reynolds number Re3 Reynolds number (Slatter) V average velocity (m/s) Vann annulus velocity (m/s) x variable X number of independent variables y variable Y number of fundamental dimensions z variable µeff effective viscosity (Pa s) ? valve degree of opening d partial derivative ? fluid density (kg/m3) [ ] function]

Jan 1, 2007

For the Gold Fields Foundation National Engineering Awards, each university affiliated to the South African Federation of University Engineering Students (S.A.F.U.E.S.) selected a candidate who, in their opinion, presented the most outstanding design project in their final year during 1984. New President On 29th March, 1985, Mr B.C. (Bertie) Oberholzer, Manager of East Driefontein Gold Mine, was elected President of the Association of Mine Managers of South Africa for the ensuing year. Bullion from old film A pollution-free chemical method of producing silver that is 99 per cent pure-and therefore of bullion quality-from scrap photographic film and paper has been developed by a British company.

Jan 1, 1985

By J. P. G. Pretorius, T. C. Partridge

The analysis of angular atypicality of lineaments as an aid to mineral exploration by J. P. G. PRETORI USc, M.Sc. (Pret.) (Visitor) and T. C. PARTRIDGE, Ph.D. (Natal) (Visitor) In an exploration project, data pertaining to 84000 lineaments in an area of 25 000 km2 were recorded. The total length of lineaments in intervals of one degree was determined. Angular intervals with Iow length densities were regarded as atypical. The proportion (by length) of lineaments with such atypical orientation was calculated for 5 km X 5 km grid squares. This index of angular atypicality was contoured and, used in conjunction with conventional photogeological techniques, contributed in a large measure to the success of the investigation.

Jan 5, 1974

By M. J. Southwood

SYNOPSIS Experiments carried out under atmospheric pressure and temperature (25°C) and sterile conditions show that the dissolution rate of nickel and copper from a pyrrhotite-pentlandite-chalcopyrite ore in a lixiviant of sulphuric acid is greatly enhanced in the presence of pyrite. At a pH value of 1,8 and in the presence of pyrite of equal mass to that of the ore, the recoveries of nickel and copper improved dramatically (21 and 80 per cent respectively). At a pH value of 4,0 the recovery of nickel was enhanced, but the chalcopyrite was refractory. A galvanic mechanism is probable, but cannot be proved from these experiments. The economic implications of the results are discussed.

Jan 1, 1985