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By N. E. K. Schuttler

Experience with Mars pumping of underground water by N. E. K. SCHUTTLER (Visitor) As the result of a planned increase in production, Vaal Reefs Exploration & Mining Company Limited increased the hoisting capacity of their existing equipment to its fullest extent and installed Mars pumps and a washing plant. The layout of the installation is described, and details are given of the modifications made to overcome its weaknesses. Plans to change the present four-stage system to a seven-stage system are outlined.

Jan 3, 1977

By J. H. Bulloch

A short review is given of the effects of corrosion fatigue on the materials used in pressurized water-reactor vessels. Selected topics such as testing procedures, test data, and mechanisms in simulated environments are discussed. The main fact that emerges is that most of the data on the growth of fatigue cracks reside below the ASME X1 1980 High-R 'Wet' design-code lines, Le. they fall within that specification. Finally, some recent advances in the understanding of the corrosion-fatigue behaviour of such materials in pressurized water reactors are highlighted.

Jan 1, 1987

By J. Ungar, F. X. McGarvey

The selectivity of ion-exchange sites varies with the matrix of the polymer, the nature of the site. and the method of application. The effect of these variables on the recovery of uranium is examined. with particular attention to vinyl pyridine and to symmetrical and asymmetrical quaternary ammonium sites. The effect, on the loading. of high concentrations of chlorides in the liquors is discussed. and other components of the liquors that may cause fouling of the resin are also considered. The discussion is supported by the results of tests conducted on various types of resins. The economics of the process is discussed briefly.

Jan 1, 1981

By N. C. Joughlin, D. K. Hallbauer

The size distribution and morphology of gold particles in Witwatersrand reefs and their crushed products by D. K. HALLBAUER, Dr. rer. nat., Dipl. Min. (Visitor) and N. C. JOUGHIN, B.Se. (Eng.), Ph.D. (Rand) (Member) Undistorted gold particles were obtained from samples of a variety of Witwatersrand reefs by dissolution of the quartz in hydrofluoric acid. The size distribution of the gold particles and their shapes and association with thucholite and pyrite are discussed. Gold particles with a natural flat, plate-like appearance occur in varying proportion in all reefs. The effect of a number of different comminution processes on the gold particles was investigated, and the shape of gold particles in mill pulp from a number of mines was examined.

By K. Levin, P. Lloyd

During the commissioning phase, which is usually the most exciting part of a project involving the design and construction of metallurgical plant, the commissioning engineers interact between the client and the project management. The client wants to see whether all the equipment that he has bought and that, in his opinion, has taken far too long to erect will actually work. Project management expects the commissioning people to con¬vince the client that this is the best design ever developed and that never before have time and money been spent so well. The commissioning team has to fulfil these expectations. Commissioning work is a `shirt sleeve' function, with little of the glamour that is normally associated with fields such as engineering and operations. The team usually works in a partially completed plant with more temporary than permanent services and little (if any) office accommodation, normal working hours do not apply, and the demands made on the team change suddenly and dramatically. This article outlines the activities of the commissioning group and the systems used to smooth the commissioning path.

Jan 1, 1981

By P. J. Kinver

This paper deals with the development of the cut-and-fill mining method at the Broken Hill orebody of Black Mountain Mineral Development Company (Pty) Limited, at Aggeneys in the north-western Cape Province of South Africa. Lead, copper, zinc, and silver are produced. Production started in January 1976, being confined to blasthole production methods in the upper, steeply dipping areas of the orebody. This blasthole reserve is 70 per cent depleted, and pillar extraction is in progress. The balance of the production tonnage, 60 kt per month, is produced from three cut-and-fill stopes situated in the flatter-dipping areas of the orebody. The cut-and-fill mining method at Black Mountain is a result of research and planning activities that included the use of modelling, laboratory tests, mathematical analyses, in situ tests, and experience gained from other mining operations. These investigations and the resulting developed methods and designs are summarized in the paper.

Jan 1, 1985

By S. Maluadzi, D. Rocchi, S. Luyckx, S. S. Potgieter-Vermaak, C. Machio, J. H. Potgieter

The aim of this work was to compare the corrosion behaviour of thermal spray WC ? based coatings before and after annealing. X-ray diffraction (XRD) was used to determine the phases present in the coatings at various stages. The corrosion resistance of the coatings was measured using electrochemical and immersion corrosion tests. The results obtained from electrochemical corrosion (quantified by corrosion current density) and immersion corrosion tests showed that annealing appears to decrease the corrosion resistance of the coatings. From the XRD results it was determined that the phases that corroded preferentially were cobalt (Co), eta (Co6W6C) and W2C. Keywords: Corrosion, thermal spray, coatings, hardmetals.

Jan 1, 2006

A banquet, attended by 467 members and visitors, was held at the Wanderers Club, Johannesburg, at 8 p.m. on Friday, 21st March, 1969, to celebrate the 75th Anniversary of the founding of the Institute. Introduction of Dr Carel de Wet R. C. J. Goode (President) Dames en here: Ons het 'n aantal vooraanstaande gaste in ons midde vanaand en mnr Maxwell sal u later meer van hulle vertel. Dit is my aangename plig om u voor te stel aan sy Edele, die Minister van Mynwese, van Beplanning, en van Gesondheid, Dr de Wet en sy gade, mev de Wet. Sy Edele Dr de Wet het geen bekendstelling nodig nie-alhoewel hy ons minister vir slegs die afgelope twee jaar is, het hy reeds talle funksies van ons Mynbedryf bygewoon en het baie vriende gemaak onder ons. Hy het homself baie bemind onder ons gemaak toe hy Wes-Driefontein onlangs besoek het om hulle ondersteuning en aanmoediging aan te bied in hulle uur van nood. The Honourable Dr de Wet was born in the Free State. He is a grandson of that very famous general Christiaan de Wet, who caused so much pain to the British forces and for so many months so successfully eluded them in the Transvaal and Orange Free State. He was educated at both the Pretoria and Witwatersrand Universities. He first practised medicine at Boksburg and then moved to Vanderbijlpark, so you see he has an early association with gold mining on the Witwatersrand, and in moving to the Vereeniging-Vanderbijlpark district he became closely involved in our coal mining and metallurgical industries. South Africa's first steel was poured from a l0-ton open hearth furnace belonging to the Union Steel Corporation in Vereeniging in 1913. Dr de Wet has been mayor of Vanderbijlpark and for several years has been their member of parliament. More recently, the Honourable Dr de Wet has filled with great honour that most important office of Ambassador for the Republic of South Africa in London. At present he wears two hats, in that he is Minister of Planning and of Health, but more important is his cloak, that of Minister of Mines, which I trust offers him the greatest comfort. To fulfill these three arduous tasks must demand of him a terrific devotion to duty, and in doing this he carries on that loyal tradition of service to his fatherland so evident in his grandfather. Dames en here, dit is vir my 'n groot genoeë om Sy Edele Dr de Wette vra om 'n heildronk in te stel op die Instituut vir Mynwese en Metallurgie. Toast to the Institute of Mining and Metallurgy Dr the Honourable C. de Wet (Minister of Mines): Mr President, ladies and gentlemen, Mr President you have introduced me gracefully to this distinguished company and I am appreciative of your remarks. I am fully conscious of the responsibilities that devolve upon me as Minister of Mines in a country where mining makes so vital a contribution to economic progress and development and has, in fact, laid much of the foundation on which our present proud edifice is built. The achievements of the mining and metallurgical industry in its diversified activities arouse feelings equivalent to paternal pride, but let me speedily add that in considering any family relationship that may exist, the Minister of Mines should not be regarded in the role either of a fairy godmother or an indulgent father.

Robert Rampton Porter died on 8th September, 1985, in Salt Lake City, Utah, at the age of 75. Bob Porter was born in Salt Lake City in 1910, and he attended the University of Utah, where he obtained an M.Sc. degree in metallurgy. Galvanizing In conjunction with the National Institute for Materials Research of the CS I R, the South African Hot-Dip Galvanizers' Association has organized the First International Conference on Galvanizing in South Africa. This event will take place at the C SIR Conference Centre in Pretoria from 3rd to 7th November, 1986. Environmental effects of mining A one-day meeting entitled 'The environmental effects of mining and restoration' will be held on 23rd September, 1986, at the University of Manchester Institute of Science and Technology, Manchester, England.

Jan 1, 1986

By M. B. Algeo

Discussion of the above paper M. B. ALGEO The management and staff of Buffelsfontein Gold Mining Company Limited are to be congratulated on the excellent performances described in the paper presented by Mr Christos. In this day and age, with the current economic and labour situation, the mining industry is being constantly pressed to increase the productivity of ever-diminishing quanta of resources. Stress in rock The ISRM Symposium, 1976 is to be held in Sydney from 9th to 13th August, 1976. It is being organized by The Australian Geo. mechanics Society as a regional symposium of the International Society for Rock Mechanics. Thermal analysis The First European Symposium on Thermal Analysis will be held at the University of Salford on 20th to 24th September, 1976.

Jan 12, 1975

By B. Litt, D. L. Van Coller

Job evaluation and the changing wage pattern by D. L. VAN COLLER, B.A.(Cape Town), M.A., B.Litt.{Oxon.) (Visitor) This paper sets out to show how changing forces are affecting the techniques that have been used in the evaluation of Black jobs on gold mines in the Anglo American Group since the introduction of job evaluation in 1961. Initially, job evaluation was essentially a management tool designed to differentiate jobs in a limited skill spectrum and thereby permit the establishment of a 'many stepped' job ladder for Black employees to climb. With the changing wage pattern, job evaluation is becoming an industrialrelations tool aimed at recognizing the skill and effort contributed by the worker so that the pay relationships between jobs are seen to be equitable by the employees.

Jan 8, 1974

By R. L. Paul

Although it is often said that South Africa does not have suitable deposits, or the potential to develop mines on a small scale, a recent survey by the Chamber of Mines1 showed that, out of a sample of 641 producers, 41 per cent had between 10 and 19 employees, and a further 29 per cent had between 20 and 29 employees. This goes to show that minerals-related small, medium, and micro-enterprises (SMMEs) do exist, and can play an important role in the development of rural industries in South Africa. Nchaka Moloi of the Department for Mineral and Energy Affairs defined the various categories of SMMEsas shown in Table I2. An enterprise could be placed in a certain category as long as two of the variables, employees, capex or production applied.

Jan 1, 1997

By C. L. Workmann Davies

Underground transport and communication in collieries was the theme selected for the 1983 mining school conducted by The South African Institute of Mining and Metallurgy. The response from the industry was so good that three separate schools of one week each were arranged, and a total of 222 delegates attended. Development of Mineral Resources The Institution of Mining and Metallurgy and The Department of Mineral Resources, Government of Thailand, with the cooperation of the Thai Mining Association and Chulalongkorn University, is to hold an international conference entitled 'Role of Government in Mineral Resources Development' in Bangkok from 5th to 8th Decembc -:" 1983. Electronics in Mining A symposium entitled 'Electronics in Mining', organized by The South African Institute of ElectriealEngineers, is to be held in Randburg, South Africa, from 18th to 20th September, 1984.

Jan 1, 1983

By D. R. Arnold

Discussion of the above paper by D. R. ARNOLDt This paper is the result of an excellent piece of work performed as a service to hyUrometallurgy in general and to the South African uranium industry in particular, and the authors are to be congratulated, Authors' reply Dr Arnold is correct in saying that the present Senbrix resins, which are based on the experimental heavy resins first developed at the National Institute for Metallurgy (NIM), need not necessarily show the same poor performance with respect to cobalt poisoning as the NIM prototypes. Oceanology International The next 01 World Conference is to be held Brighton, England, from 2nd to 7th March, 1980. The programme will concern technical advances in the offshore oil and gas industries, and is expected to include 140 papers from 20 countries.

Jan 1, 1979

By J. le Grange, M. Tullmin, A. Strauss, F. P. A. Robinson, C. A. O. Henning

An experimental feritic stainless steel with a chromium content of 40 per cent was welded by laser and electron beam (EB) welding processes. These techniques were found to be particularly suited to the welding of this alloy in that the impact toughness of the weld metal and heat-affected zone (HAZ) of the laser welds compared favourably with those of the parent aloy. When the EB process was used, the impact toughness of the weld metal was over 180 J/cm2. Grain growth in the HAZ was minimal for welding with these two processes. Corosion tests, conducted in a solution consisting of 20 per cent sulphuric acid and 100 p.p.m. of potassium thiocyanate, and In a highly corrosive industrial solution, indicated that the laser and EB welds were free of sensitization effects, thus confirming the metalographic results.

Jan 1, 1989

By S. Nana, M. B. Cortie

Duplex stainless steels containing high levels of manganese and copper and lower-than-normal levels of nickel were produced and evaluated. The experimental alloys containing 3 per cent copper by mass could not be successfully hot-rolled. Alloys containing less than 2 per cent copper could be hot- and cold-rolled without difficulty. The wrought experimental alloys that contained copper were found to offer some advantages over the 2205- type duplex stainless steel in sulphuric acid at 52°C. Resistance to pitting attack was governed primarily by the chromium, molybdenum, and nitrogen contents, and one of the experimental alloys was superior to the 2205-type alloy in the ferric chloride test. It is concluded that manganese is a useful substitute for nickel in duplex alloys, but that further work is required before the present alloys, or variations of them, could be commercially viable.

Jan 1, 1993

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, A. T. Pieterse

An account is given of the performance of a 37 MVA electric-arc .furnace in which bottom stirring with inert gas by an indirect-contact stirring-plug system was applied. The system, which was developed and patented by Thyssen-Stahl AG, and which is the first inert gas stirring system to be installed in South Africa, was commissioned in January 1992. Initial problems were experienced due to the blockage of stirring plugs by molten steel. The causes of these malfunctions are examined, and an account is given of how they were overcome. The system is described and evaluated. A comparison with direct-contact stirring systems shows why Iscor Vereeniging Works considered it to be more suitable for their Vaal Melt Shop. The results show that, through the successful application qf this technology, Iscor Vereeniging Works has achieved an annual cost saving of more than R2,5 million.

Jan 1, 1994

By V. J. Moore

Introduction Although months have passed since APCOM 87, held from 19th to 23rd September, 1987, the vivid memories of all aspects of its activities remain as clear in one's mind as if it all happened only yesterday. The Symposium, which was held at the Johannesburg Sun Hotel, was organized by The South African Institute of Mining and Metallurgy in collaboration with the Council for Mineral Technology (Mintek), supported by The Geostatistical Association of South Africa, The Operations Research Society of South Africa, and the Computer Society of South Africa, and was backed financially by the Chamber of Mines of South Africa. The total number of registrants amounted to 375 delegates and 50 affiliates: 100 of the delegates were from outside the Republic of South Africa and represented 15 countries, namely Australia, Brazil, Canada, Chile, France, Great Britain, Greece, Italy, Namibia, Phillipines, Sweden, Turkey, United States of America, West Germany, and Zimbabwe.

Jan 1, 1988

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