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By N. R. Shoko, J. Chirasha

Refractory design remains the most fundamental factor in furnace construction. Refractory design details and proven technology consideration is of paramount importance to come up with an optimum furnace life and to maintain productivity in the life span of the furnace lining. The failure to produce a technically or operationally durable refractory design lining could give rise to pre-mature deterioration of the refractory lining and furnace shell. The premature failure of the furnace lining will lead to extensive heat losses, furnace bath shift, change in taphole orientation and alteration of the Pitch Circle Diameter. A combination of these were experienced at Zimbabwe Alloys? new high carbon ferrochrome furnace. The Zimbabwe Alloys experience has shown an excellent furnace performance in the first two years of operation although signs of an anomaly showed within the first six months of the new furnace. Production slowed down due to induced problems from refractory failure causing furnace distortions impacting on the availability of the furnace and smelting capacity. This paper presents the lessons learnt, measures taken to deal with the premature failure and constraints within which the situation was managed.

Jan 1, 2007

The Floatability Characterisation Test Rig (FCTR) is a self-contained, highly instrumented, mobile pilot plant. It was developed as part of the AMIRA P9 project, primarily to determine ore floatability characteristics and to develop and validate flotation plant modelling, scale-up and simulation methodologies. This paper describes the use of the FCTR in validating the AMIRA P9 flotation model and modelling methodology. In 2001 the FCTR was installed and operated in parallel with WMC's (now BHP Billiton's) Kambalda Nickel Operation. The FCTR was operated using four different circuit configurations of increasing complexity. Metallurgical surveys, cell characterisation measurements and batch flotation tests were performed around each circuit. This allowed the calibration of a number of flotation models using a combination of data from one, two, three or four circuit configurations. The calibrated flotation models were then validated using predictive validation. To do this, data around a further five FCTR circuit configurations were collected (three of which are presented in this paper). The performance of each of the five circuit configurations was predicted using JKSimFloat V6.1 and the parameters from the various calibrated flotation models. The predicted performance was compared to the experimentally determined performance of each circuit. The validation of the AMIRA P9 model was shown to be largely successful except in the case where the reagent addition (depressant) to the validation circuit was different to that in the calibration circuits. The results also provided information regarding the required complexity of the calibration circuit and how many calibration circuits are required to obtain an accurate prediction of circuit performance. These results have increased the confidence in the AMIRA P9 flotation modelling methodology and have provided important information on what data must be collected to allow the accurate prediction of plant performance using the floatability component modelling approach.

Jan 1, 2007

By O. S. Tinkler, K. C. Sole

"Although the first large-scale application of copper recovery by solvent extraction took place in Zambia in the early 1970s, it is only in the last decade that this technology has become widely employed in this part of the world and is now a mainstay unit operation in copper hydrometallurgical flow sheets. The mineralogy of the ores of the African Copperbelt, and hence the characteristics of African leach liquors, differs significantly from those in Chile and the southwestern USA, where copper solvent extraction has had a long and successful history. These differences provide operators, metallurgists, reagent vendors, and engineers with many challenges: new approaches are needed to adapt solvent-extraction technology for successful implementation in this region. This paper examines typical operating practice in the African Copperbelt, discusses differences compared with other parts of the world, and looks at some of the challenges and opportunities presented by these flow sheets. IntroductionFollowing the success of the Rancher’s Bluebird and Bagdad solvent extraction and electrowinning (SX–EW) operations in Arizona in the late 1960s, the Tailings Leach Plant at Chingola, Zambia, became the first large-scale copper SX plant in the world, commissioned in 1974. Despite the equipment design now being outdated, this plant still continues to operate successfully, indicating the versatility and adaptability of this technology. Today, there are some 75 copper SX operations worldwide with cathode production above 10 kt/a. The top ten producers currently account for about 40% of the global 4.3 Mt/a SX–EW copper production. South America (predominantly Chile and Peru) is the largest copper cathodeproducing region, with annual production of some 2 Mt. The Central African Copperbelt (Zambia and the Democratic Republic of Congo (DRC)) is second, with cathode production of 1.2 Mt/a, and North America (USA and Mexico) third, producing close to 0.8 Mt/a Cu (Solvay Cytec data, 2014). The remaining 0.35 Mt/a comes from all other regions combined (referred to as ‘Rest-of-World’)."

Jan 1, 2016

By G. L. Gomes-Sebastiao, W. W. de Graaf

"Gomes Sand is a quarry operation that produces sand and aggregate for the construction industry. The quarry is experiencing inconsistencies in the fragmentation and poor pit conditions as a result of poor drilling and blasting practices. This results in excessive downtime in the load and haul and crushing processes.A benchmarking exercise of the blasting practices was conducted to evaluate the effect of the inconsistency on the mining cycle. After changes in the blasting practices the downtime was reduced, which improved the crushing plant utilization by 4.9%. The improved blasting practices and more consistent fragmentation decreased the average number of loads lost each month due to jaw crusher blockages from 9.2% to 3.9% of plant throughput. The change in blasting practices also improved pit conditions. IntroductionGomes Sand is a quarry operation that has been in operation since 2009, producing sand and stone for the construction industry. The quarry was experiencing unacceptable blasting results. The repercussions included uneven pit floors, large amounts of oversize rock (>500 mm), and inconsistent fragmentation.The blast results affected the load and haul operations as well as the efficiency of the crusher. This resulted in downtime in the daily operations, and consequent production and revenue losses.The crusher product should have a top size of 50 mm. A blast fragmentation of <50 mm would improve the downstream operations and the crusher throughput.An investigation into the blasting practices was carried out to assess whether the downstream delays can be eliminated by improving the blast results. The exercise included:* Assessing if the designed blast layout is adhered to on the bench* Observing the quality and control of drilling* Observing the charging procedure of the blast-holes* Benchmarking the fragmentation consistency of the blasted rock using current blast design and practices* Analysing the throughput of the crushing plant* Investigating the power consumption of the crushing plant and determine if a change in blasting practices will affect this* Evaluating the hours spent by the hydraulic hammer on secondary breaking."

Jan 1, 2017

By F. M. Russell

Scheduling the extraction and rates of production for an underground mining operation is a common task carried out during the life of a mine, from the initial feasibility study through to the final production phase. The scheduling process can be complex when several requirements have to be satisfied, for example, match mill capacity and maximize net present value while constrained by mining sequence and availability of resources. Many mines have computer programs relevant to their operation but because they are site-specific they need considerable reprogramming to be adapted to other operations. Other methods currently in use also suffer drawbacks: manual spreadsheets are laborious, computerized spreadsheets cannot handle sufficient constraints, and operations research techniques require a complex mathematical model to be set up. The use of network analysis techniques has been proposed previously but the unavailability, until recently, of easily used computer programs has not allowed this approach to be developed. There are now many programs which can be used; however, the particular program which has been adapted to mine scheduling is Metier&apos;s &apos;Artemis-PC&apos; running on IBM-XT or compatible machine. The use of network analysis offers many advantages, including the use of a logical mining sequence; activities can be as detailed as required; related activities can be readily incorporated, and costs can be easily extracted. A heuristic approach is necessary to optimize the schedule, but the ease and speed of program execution enables this to be readily achieved, while leaving the mining engineer in full control. The paper discusses the problems encountered in mine scheduling and current solutions. It then details the use of network analysis techniques and the application of the Artemis-PC program to solve mine scheduling problems.

Jan 1, 1987

By H. A. D. Kirsten

The skills differential between manpower supply and demand is due to deeply rooted socio- and politico-educational misconceptions that can be remedied only by a concerted cooperative effort on the part of the general public, the State, organized industry, organized engineering, and engineering education. This will require the general public to recognize that the reasons for the shortages in engineering manpower should be regarded as critical. Public perceptions of engineering, of the vocational and educational prospects in engineering, and of the skills required are poor. The spectrum of engineering vocations, the corresponding function profiles, the interaction between the vocations and the relative proportions of the vocations in the engineering team are in general not adequately appreciated. The recruitment and training of students and teaching staff, teaching facilities, educational curricula, practical training, qualifications, professional registration, and financing are aspects of engineering education that should be brought to the attention of all concerned. . In addition, the educational curricula for the various vocations need to be specified clearly and definitively if the overall mission of engineering education is to be properly appreciated. The uncertainties between university and technikon education and the pursuant vocations need to be resolved. This can be done only by defining the respective curricula in terms of the mental skills and scientific techniques required. The remedial actions with regard to the rationalization of engineering education comprise informing of the public; establishment of an active political lobby; revision of existing education policy; rationalization of existing educational infrastructure; promotion, development, and guidance of engineering student intake; financing of engineering education; accelerated creation of new employment opportunities; and monitoring of the supply and demand of high-level manpower. The parties required to nitiate these remedial actions are various State departments and corporations involved in engineering and industry, various departments of education, the Directorate of Technology of the Department of Trade and Industry, organized engineering education, organized engineering, organized industry, and the Human Sciences Research Council. Only if these interest groups actively initiate the various actions under the coordinated guidance of organized engineering wil the required results be achieved. The South African Engineering Association has proposed a comprehensive programme as strategy to solving the problem, and has obtained broad consensus from various State departments, organized engineering education and research, and the private sector. A joint venture between the Foundation for Research Development, the South African Engineering Association, and organized industry has been charged by the State President with the task of launching the programme.

Jan 1, 1991

By K. Tobór-Osadnik, M. Wyganowska, A. Manowska

"The behaviour of employees is an essential issue in the field of occupational health and safety. Safe behaviour is to a large extent determined by, apart from motivation and preventive actions, an employee’s attitude towards hazard. Thus, attention should be given to defining employees’ attitudes, and following that, to the possibility of correcting and shaping these attitudes in relation to hazard and obeying occupational health and safety regulations. The authors have focused on the analysis of employee attitudes to health and safety regulations in Polish coal mining companies, taking into consideration earlier research on the behaviour of selected employees. The paper presents the methods used to identify Z-type (passive) behaviour. Next, this behaviour is analysed to identify differences between a Z-type employee (enslaved) and other employees. To conclude, the paper presents a list of possible motivational tools that may be used to encourage occupational health and safety in Z-type employees. IntroductionThe technical state of equipment and conditions in the workplace greatly influence occupational safety. However, the deciding factor influencing the rate of accidents in the workplace is the frequency with which employees practise risky behaviour. Factors such as the social conditioning of conduct and motivation for organizing safe work conditions have been included in the notion of creating a positive culture of work safety. This notion has been approved as one of the main goals in management (Studenski, 1996).Safe behaviour is to a large extent, apart from motivation and preventive actions, determined by an employee’s attitude towards hazard. All actions undertaken in the field of occupational health and safety, including training, motivational systems, or imitation of behaviour resulting from a high culture of occupational safety in a given work environment, will not bring about the desire effects if workers have an inappropriate attitude towards occupational health and safety regulations."

Jan 1, 2017

By Oaitse Medupe

The feed to the BCL concentrator is made of the ore from Phikwe No3 shaft, Selebi shaft and Selebi North shaft. The receiving bin of the concentrator has daily throughput of 7869mt live capacity of ore with feed grade from underground operation of 0.70%Ni, 0.75% Cu and 0.05% Co. The valuable minerals in the ore are Pentlandite, Chalcopyrite. Cobalt is present mainly in the solid solution in pentlandite. The common non-sulphides minerals are Amphibolites, quartz, micas, and Feldspar while pyrite and pyrrhotite are the major gangue sulphides. Pyrrhotite contains between 0.1% and 1% Ni in solid solution. From the mineralogical investigation, it was found that approximately 65% of the pentlandite in the ore occurs as exsolutions in the pyrrhotite and the grain sizes ranges from 8 to 38µm. about 25% of the nickel bearing pentlandite is medium grained and subhedral. This kind of pentlandite occurs along the cracks of pyrrhotite or as inclusions in pyrrhotite. The rest of pentlandite present is disseminated in the gangue matrix. Because of the fine occurrence of pentlandite, fine grinding was conducted in order to improve the recovery as well as the concentrate quality. A series of subsequent flotation test were performed in order to evaluate grinds of 35, 40, 45, 50, 60 and 80% passing 75µm. It was observed that ? The mass pull increased together with increasing fineness of grind ? Similar nickel recoveries were obtained at 35 and 40% passing 75µm but from 50% and 60% the grind was seen to adversely affect the nickel recovery. At 80% passing 75µm the recovery increased by small amount. ? Flotation kinetics showed higher initial nickel recoveries but these did not translate into higher final recoveries. ? Grinding finer than 80% passing 75µm yield very high grades of the concentrate in the first minute of the flotation test, and the grade is dramatically reduced in the fifth minute of the test. It was concluded that the current grind of approximately 48% passing 75µm is close to the optimum and no significant benefit were found to be associated with finer primary grinds. The inconsistence of the grade and recovery as well as the pentlandite losses will be discussed. Keywords: Pentlandite, Nickel losses, Grain size, Flotation

Jan 1, 2007

Mining executives often have a difficult task determining what the strategic objective of the business should be as this can be impacted by the prevailing market conditions. In addition, they have no mechanism to quantitatively &apos;test&apos; the impact of this strategic decision on the business and understand the underlying dynamics. During the commodities bull run of 2003 to 2008 the strategic objective may have been to grow the long term value of the business (NPV) through increased tonnage, acquisition and finding new reserves, which all came with an increasing fixed cost base. Now with the financial crisis upon us and the collapse of commodity prices and demand, executives have adjusted their strategies as &apos;cash is king&apos; and short-term cash flow, in some instances at the expense of long terms value, is the order of the day. For many mining companies, mine closures, reductions in production and cost cutting exercisers are now the focus. In many instances, management do not have an ability to rapidly test different strategic alternatives to &apos;test&apos; the impact on value, unit costs, reserves and profitability at the operational level and optimize the underlying trade-off variables. Economic modelling of the complete business value chain is a means of linking the operational &apos;reality&apos; and strategic choices, so that the full impact can be assessed. This paper describes some of the challenges facing mining executives and how economic modelling can be applied to make decision making more rigorous.

Jan 1, 2010

The Institute was founded in 1894 as the Chemical and Metallurgical Society of South Africa. In 1904 it was reconstituted as the Chemical Metallurgical and Mining Society of South Africa and in 1956 it became the South African Institute of Mining and Metallurgy. The objects of the Institute are to advance the science and practice of mining and metallurgy, to afford opportunities for the interchange and recording of knowledge of mining and metallurgy and to ensure high standards of professional conduct and competence. Membership benefits include monthly issues of the Journal of the Institute, General Meetings at which papers are read, symposia, excursions to mining and industrial concerns and the use of club facilities at Kelvin House. Technical journals received on an exchange basis are available to members at the Johannesburg Public Library. The current membership of the Institute is over 1 600. Membership applications are accepted from suitably qualified persons and the requirements for entrance to the various grades of membership are summarised below. Fellows shall not be less than 30 years of age, shall be university graduates in pure or applied science or shall produce evidence to the satisfaction of the Council that they have successfully completed a co-ordinated course of study in pure or applied science of at least three years&apos; duration at an approved university or institution deemed by the Council to be of equivalent status. Members shall have been employed in senior technical positions in important mining or metallurgical undertakings for at least five years or they shall have practised as mining or metallurgical consultants for at least five years. They shall be practising their profession at the time of application. Entrance fee R10,00, Annual subscription R20,00. Letters of designation: F.S.A.I.M.M. Members shall be not less than 25 years of age and shall be university graduates in pure or applied science, or shall have successfully completed co-ordinated courses of study in pure or applied science of at least three years&apos; duration. They shall have been engaged in work of an approved technical character in the mining or metallurgical industries, of which not less than two years shall have been in positions of responsibility. A candidate shall be practising his profession at the time of his application. Entrance fee R8,00, Annual subscription R18,00. Letters of designation: M.S.A.I.M.M. Associates shall be not less than twenty-five years of age, and shall have been engaged in positions of responsibility in, or associated with, the mining or metallurgical industries for periods of not less than three years. If, however, the candidate for admission to the higher grade of Associate, is at the time of his application, already a Student, he need satisfy the Council only that he is, at the time of his application, engaged in a position of responsibility in or associated with the mining or metallurgical industries. In all cases the applicants shall satisfy the Council that they are fit and proper persons to become Associates. Entrance fee R8,00, Annual subscription R18,00. Graduates shall be not less than 21 years of age and shall be university graduates in pure or applied science, or have completed co-ordinated courses of study in pure or applied science of at least three years&apos; duration at an approved university or institution. They shall not remain Graduate members after attaining the age of 30 years without the permission of Council. Entrance fee R2,00, Annual subscription R12,00. Students shall be persons not less than 18 years of age who are being educated or trained in a manner approved by the Councils to occupy a technical position in or associated with the mining or metallurgical industries and who, furthermore, shall not have attained the qualification required for a higher grade of membership. They may remain Students until they have obtained the necessary qualifications for transfer to a higher grade of membership, but not after the end of the Institute&apos;s financial year in which they attain the age of 28 (twenty-eight) years. They shall then transfer to a higher grade to retain membership of the Institute. The Council may relax the provisions of this clause in such cases as it considers appropriate. Entrance fee nil; Annual subscription R5,00. Other. The Council has the power to elect to the grade of Fellow or Member, candidates who may not fulfil all the requirements for entrance to these grades but whose status, professional achievements and practical experience in mining or metallurgy justify such election. Applications. Requests for membership application form should be addressed on the attached form to the Secretaries South African Institute of Mining and Metallurgy, P.O. Box 61019, Marshalltown, Transvaal.

By D. D. Howat

In the field of high temperature smelting processes there have been two dramatic changes in the past twenty years. These are, first, the application of tonnage oxygen for direct injection for the refining of molten iron and other metals and to provide the means of enriching air used for the combustion of fuel. Second, the application of electric power for the generation of high temperatures in place of the combustion of fossil fuels. Of these two developments the application of tonnage oxygen for the refining of molten iron has virtually revolutionised the steel industry throughout the world. The magnitude of this development is exemplified by the fact that less than 5 per cent of the world&apos;s steel production in 1960 was made by this process or 16 million tons out of a total of 350 million tons of steel produced, while in 1970 over 40 per cent of the world steel production was made by this process, ie, 251 million tons out of 628 million tons total. In the same period the proportion of steel produced by the old-established open-hearth process has shrunk from 75 per cent to 38 per cent. In the whole history of the development of high temperature metallurgical smelting processes there has never been anything remotely approaching this. The other development, the application of electric power for the generation of high temperatures has not had the impact of the oxygen injection process but I believe that what we should call the electric smelting revolution in metallurgical processes has very far-reaching ramifications for steel production and other pyrometallurgical processes. This may seem a bold and brash statement but it must be remembered that the oxygen injection process constitutes a link in the chain critically dependent upon the production of vast tonnages of molten iron from very large modern blast furnaces. The Achilles heel of this chain of processes, upon which such a large percentage of the world&apos;s supply of steel depends, is the availability of metallurgical coke in turn dependent on natural resources of coking coal. Without any exception each industrial country in the world faces a shortage of resources of coking coal and in some cases a critical shortage. Certainly within the present century the major iron and steel producing countries of the world will face this critical shortage of coking coal and major modifications to steel making processes will become inevitable. W. F. Cartwright (Deputy Chairman of B.S.C) said recently that there are considerable doubts as to whether the world will be able to provide enough coking coal to meet world steel demands from the late 1970&apos;s onwards if the B.F.remains the main means for making iron from ore. This is one of the supreme ironies of the world metallurgical situation to-day when the technology of iron and steel production has reached an extremely high peak of technical efficiency. The newest modern iron blast furnace capable of producing 6 000 to 8 000 tons per day of molten iron represents probably the most efficient piece of high temperature metallurgical plant and operation known to man. The conversion of this molten iron into steel by the oxygen injection process has made available to the engineering industry steel of a quality and at a price which is quite remarkable. Yet this vast metallurgical pyramid rests on the completely insecure and uncertain foundation of inadequate world resources of coking coal. The shortage of reserves of coking coal in this country is acute and it is possible that these resources will be exhausted within the next twenty years. Yet unless some completely unexpected catastrophe occurs the demand for steel in this country will probably rise at a faster rate than in the Western world due to the expansion of the Bantu population and the increased standard of living. To offset the inevitable shortage of coking coal are our much greater resources of bituminous coal which although of low grade provide a suitable fuel for electric power generation. The geographical disposition of the coal fields in relation to the great industrial areas of the Transvaal makes it inevitable that the development of the pyrometallurgical industries must depend heavily on electric power. The position in this country with regard to electrical power generation and consumption is rather anomalous. Per capita consumption of electric power is high - in 1964 almost twice the world average of 870 KWH and twenty-five times the average of 34 KWH for the Continent of Africa. In 1964 fifty-four per cent of the total world electric power was used in industry - the ratio being approximately 1/9 mining to manufacturing uses. As shown in Table I in 1969 67.2 per cent of the total output of electric power from ESCOM was used for mining and other industrial uses but almost in the ratio 6/4 mining to industrial uses. These figures emphasise the enormous importance of the mining industry to the economy of this country and underline the major contribution made by the gold mining industry. What is of very significant importance is that although the mining industry remains by far the largest single consumer of electrical power the consumption of power for industrial uses is rising rapidly as shown in Table II.

The November General Meeting of the Institute was held in Kelvin House, Johannesburg, on Wednesday, 18th November, 1970, at 4.00 p.m. V. C. Robinson (President) was in the Chair. There were also present 30 Fellows, including J. K. E. Douglas, R. C. J. Goode, Dr J. P. Hugo, Prof J. de V. Lambrechts, D. G. Maxwell, Prof R. P. Plewman, Dr M. D. G. Salamon, P. W. J. van Rensburg, L. W. P. van den Bosch (Council Members), R. E. Burnton, S. Craib, D. de Villiers Oxford, J. C. Fritz, G. W. Gray, G. H. Henderson, S. D. Hill, C. H. Kruger, B. Leach, C. S. MacPhail, D. J. Molony, W. G. Fyne Mercier, R. A. Scott, M. v. R. Steyn, I. E. van Aswegan, A. D. Vos, J. M. Vosloo and N. Zolezzi. Four Members, including I. G. Evans, R. W. Shearer, W. Wilson. One Associate: P. M. C. Wilson. Four Students: H. G. Albertyn, J. T. Davies, P. G. Henderson and P. J. Pretorius. Fourteen Visitors, including S. R. Barker, F. H. Deist, Dr de Jager, L. F. Duvel, P. du P. Kruger, B. D. Maree, B. R. Meyer, R. Redmond, J. Rietief, A. W. S. Schumann, Mrs A. W. S. Schumann, T. S. Stoffberg, C. A. Visser and R. van der Wait. Secretary, D. C. Visser. Total present 55. The President: "Gentlemen, I would like to welcome all members of the Institute who are present, and visitors, and I would like specially to welcome any members of the Suid-Afrikaanse Akademie who are present this afternoon." OBITUARIES The President: "Before starting on the agenda the first item, of course, is unfortunately obituaries and it is my sad duty to announce the death of the following: I would like to start with a person who is not actually a member of the Institute but who, in his capacity as President of the Chamber of Mines, was Honorary President of this Institute three times and I refer, of course, to Mr Herman Calderwood Koch who passed away last Saturday. Then I would refer to Richard Beaumont Tasker, Life Fellow, who joined this Institute in 1932, and who died on the 22nd of October, 1970. Then, lastly, Mr Jean Francois du Plessis, a student, who joined the Institute on the 19th June, 1968, and passed away on the 11th of November, 1970, as the result of an accident. Mr du Plessis was to have received a Student Prize today for his paper entitled, Displacements and stresses in the vicinity of a horizontal long-wall&apos;. We were all most upset to learn of his death last week, and we are now going to make arrangements to hand his prize to his widow on a suitable special occasion. As a mark of respect to the memory of the deceased, and in sympathy with the bereaved, I would ask you all to stand and observe a few moments&apos; silence. Thank you." CONFIRMATION OF MINUTES The President: "May we confirm the minutes of the monthly general meeting which was held on 16th September, 1970, as published in the November Journal?" Agreed. MEMBERSHIP The President: "I have much pleasure in announcing that the names of the undermentioned candidates having been published in accordance with By-Law 5.2.2, Council has elected them to membership of the Institute in the following grades: Fellow: Ronald White Ballantine. Members: Jan Johannes Hertzog Viljoen, Agge Petrus Rutgerus van der Meer, Peter Anthony Reynolds, Ernest Esdaile Leyde Hans Lutz Klingmann, Ronald Archer.&apos; Graduates: Trevor Stanley Schultz, Thomas Cochrane Meiklejohn, Leslie Harold Heyman, Dennis William Bosch, Sydney Stuart Absolom. Associates:Roderick James.Vermaak, Theodorus Daniel van Wyk, Michael Osmond Savignac Stedman, Leslie Owen Raymer, Bryan Arthur McKay, Leon Ellis Finlay Leask, Dudley Graham Lovedren Hall, John Arthur Gibbon, Richard Reginald de Villiers, Carel Frederik Boshoff. Students: Frederik Wilhelm Christian Coetzer, Phillippus Johannes de Wit, Jan van der Merwe Grimes, Davood Khareghani, Jan Wolvaardt Oberholzer, Johannes Lodewikus Pretorius Pieter Jacobus Strobos, Herbert Gerald Waldeck.&apos; MEMBERS TRANSFERRED TO A HIGHER GRADE From Associate to Fellow: Howard Mitchell Wells. From Associate to Member: Ernest John Dominy. "I welcome the newly elected members to the Institute and congratulate the members who have been transferred to a higher grade." AWARDS The President: "It is with very great pleasure that I can announce that Council has agreed to make the following awards for papers presented to the Institute during the year ended July, 1970. Gold Medals to Prof Plewman and W. D. Ortlepp for their paper entitled &apos;The development and application of a digital computer method for the solution of strata control problems&apos; written jointly with F. H. Deist (Visitor) and presented in September, 1969. A Silver Medal to Dr Finkelstein for his paper entitled &apos;The Influence of sulphydryl and cationic flotation reagents on cyanidation of native gold&apos; written jointly with Dr K. G. Ashurst (Visitor), and presented in June 1969 at the Symposium on the Recovery of Pyrite. &apos; May I congratulate these gentlemen on the high honour they have won with their papers. As new medals are in the process of being designed the actual awards will be made at a later date to be announced to members.

COUNCIL The following served on Council during the year under review Office Bearers Dr J. P. Hugo (President), P. W. J. van Rensburg and Professor R. P. Plewman (Vice-Presidents), Professor D. D. Howat (Immediate Past-President), and D. G. Maxwell (Honorary Treasurer). Ordinary Members of Council H. P. Carlisle (until February), R. C. Espley-Jones, G. H. Grange, Dr D. I. Legge, W. W. Malan, J. B. Mudd, Dr R. E. Robinson, Dr M. D. G. Salamon, L. W. P. van den Bosch, D. A. Viljoen (co-opted May 1973), and P. A. von Wielligh. Branch Chairmen A. Bain (Witbank-Middelburg Branch), C. J. Isaac (O.F.S. Branch). Past Presidents Serving on Council R. J. Adamson, M. Barcza, H. Britten, J. K. E. Douglas, R. C. J. Goode, P. Lambooy, Professor J. de V. Lambrechts, Dr J. T. McIntyre, J. F. Reid, and V. C. Robinson. Ten Council meetings were held during the year, with an average attendance of 18, and the standing committees held 29 meetings. MEMBERSHIP Twelve Fellows, ten Members, twenty-one Graduates, eleven Associates, thirty-one Students, and forty-two Company Affiliates were elected during the year. One Member was reinstated. Eight Fellows, two Members, and two Associates were admitted to retired membership. Four Graduates were transferred to Members, one Associate to Member, three Students to Members, one Graduate to Associate, two Students to Graduates, and one Student to Associate. Your Council records with deep regret the death during the year of the following : D. R. Campbell, J. Daniel, M. J. Dennehy, and F. S. C. Rogers (Life Fellows) ; W. T. balling and T. Pryor (Life Members); C. Boocock, W. Drake R. J. Moore, M. P. Pearse, J. M Pike, W. A. Schwezoff, A. I. Suss man, and L. G. S. Wright (Fellows) ; A. F. Chalmers (Member) ; and W. R. Gerry and G. T. Rimmer(Associates). A comparative statement of membership as at 30th June, 1973, and the end of the previous year it shown in the following tabulation: 30th - 30th June, - June, 1972 - 1973 Honorary Life Fellows 5 - 4 Honorary Fellows 13 - 9 Life Fellows 181 - 177 Fellows 541 - 536 Members 479 - 487 Graduates 115 - 128 Associates 182 - 186 Students 162 - 183 Company Affiliates 24 - 64 1 702 - 1 774 JOURNAL The papers that were published in the Journal during the year are listed below: August, 1972 The effects of chromium oxide, iron oxide, and calcium oxide on the liquidus temperatures, viscosities, and electrical conductivities of slags in the system MgO-Al2O3-SiO2, by M. S. Rennie, D. D. Howat, and P. R. Jochens A study of the dust exposure of South African white gold miners, by R. J. Page-Shipp and Elizabeth Harris A forecast of the coal and uranium requirements for electric power generation in South Africa, by E. J. Maunders September, 1972 Mine management by objectives, by A. A. Hazell Some aspects of the deformation behaviour and temperature rise during instantaneous compression loading of high purity aluminium, by H. J. E. Hamel Computer control of flotation at the Ecstall concentrator, by M. P. Amsden, C. Chapman, and M. G. Reading Optimizing the public gains from the exploitation of mineral resources, by A. Azis and J. Zwartendyk October, 1972 Presidential Address: Nuclear energy: its interactions with mining and metallurgy, by J. P. Hugo Presidentsrede: Kernenergie: sy wissel-werkinge met mynbou en metallurgic, deur J. P. Hugo Raise-boring experiences in the gold mines of the Anglo American Corporation Group, by J. W. Wilson and P. C. Graham November, 1972 Materials for winding plant components, by G. T. van Rooyen An analytical solution to the batch-comminution equation, by R. P. King A new approach to the study of human factors in stope productivity, by A. C. Lawrence Fundamental studies of the flotation process: the work of the National Institute for Metallurgy, by N. P. Finkelstein and V. M. Lovell Growing use of deionised water in surface coating techniques, by W. F. Lorch December, 1972 The development and application of a computer system to aid in the planning of production in mines, by F. H. Deist, L. F. Duvel, J. D. Austin, and H. D. Small PERT, and how PERT techniques can be used in modern mine management, by E. J. Boome and A. C. Schmidt A critical comparison of specific cooling power and the wet kata thermometer in hot mining environments, by J. de V. Lambrechts January, 1973 Liquidus temperatures in the Cr-Fe-Si system in the composition range representative of ferrochromium-silicide produced in South Africa, by J. C. M. Wethmar, D. D. Howat, P. R. Jochens, and O. A. W. Strydom Platinoids in the Witwatersrand System, by C. A. Cousins The development of a continuous recording scintillation counter mounted on a cyclometer, by P. D. Teens and D. Visser February, 1973 Computer analysis, modelling, and optimisation of gold recovery plants of the Anglo American Group, by M. I. Brittan and E. J. J. van Vuuren The significance of the mineralogical and surface characteristics of gold grains in the recovery process, by C. E. Feather and G. M. Keen Statistical valuation of diamondiferous deposits, by H. S. Sichel March, 1973 The effect of the reactivity of lime on desulphurisation efficiency in the basic oxygen furnace, by A. A. Hejja, D. D. Howat, and P. R. Jochens A review of real-time particle size analysers, by A. L. Hinde In situ measurements of the surface heat transfer coefficient in underground airways, by K. R. Vest April, 1973 An investigation into the kinetics and mechanisms of the oxidation of iron (II) by oxygen in aqueous chloride solutions, by R. P. Colborn and M. J. Nicol Electric smelting at Rustenburg Platinum Mines Limited of nickel-copper concentrates containing platinum-group metals, by J. C. Mostert and P. N. Roberts Metallurgical considerations in the

Jan 10, 1973

Jan 1, 1981

By J. B. Parry

Three types of high-strength cold-rolled steels are discussed. Two are currently being developed at Iscor: rephos phorized steel and niobium microalloyed steel. Heat treatment after cold rolling is carried out in batch annealing furnaces. A third type, dual-phase steel, which requires a continuous annealing treatment for economic production, is also described. The properties, strengthening mechanisms, and applications of these three steels are examined.

Jan 1, 1983

By G. E. Blight

The mining industry is making increasing use of pumped tailings fills. The properties that affect the performance of tailings fills are described by means of typical examples. They are the particle-size grading for maximum density, the water content for pumpability, settlement after placing, compression and drainage under stress, shear strength, and resistance to shock loading.

Jan 1, 1979

By J. L. Taylor

The belt-filtration plant at Chemwes Limited has been in operation for three years. The plant design is discussed. Operational and engineering problem areas are reported, and where possible the modifications or practices that led to their solution are mentioned. Capital and operating costs, together with selected general operating data, are also included.

Jan 1, 1983

By P. C. Seligmann

The theory of firing of electric detonators is developed insofar as it affects the design of blasting circuits. Practical values for the firing conditions suited to detonators of local manufacture are tabulated. The design principles of blasting circuits are outlined. This information can be used by mine management to ensure that electric blasting will be done efficiently and economically.

Jan 1, 1979

By H. W. Byerlee

A contactor has been designed that avoids solvent loss due to coalescence and other causes. This consists of a column packed with grids. Slurry enters at the top and flows as films down the inclined surfaces of the grids. The solvent, which fills the column, flows counter currently to the slurry. Tests on, and modifications to the contactor are described. &apos;

Jan 1, 1982

By G. Paul

The mechanism of nodular crystallisation of graphite in the production of spheroidal cast Iron is not fully understood. The work reported In this paper confirms that in cast iron melts having a high Interfacial tension against the environmental atmosphere, the graphite tends to crystallise in nodules during solidification. The Influence of Interfacial tension between melt and solid graphite is similar.