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Actual observations of rockburst damage, together with some theoretical considerations, strongly suggest that conventional approaches to the design of tunnel support are inappropriate where there is a significant seismic risk. The present widely used support systems, which are based on stiff, fully grouted re-bars, are inadequate where rock displacement velocities exceed 1 m/s. It is shown by means of a simple conceptual model that yielding of the support elements is essential to ensure their survival when they are subject to the high strain rates typical of severe rockbursts. The model proposes that the total load in the element is an impulsive tensile force imposed and sustained by a single 'tributary' block ejected from the tunnel wall. The stability of the system is determined from a comparison of the kinetic energy developed by the block with the energy of deformation absorbed by a grouted steel tendon. A novel test procedure was developed for the validation of this approach, and for an examination of the energy-absorbing capacity of stiff and yielding tendons. The results of an initial series of tests showed that the recently developed cone-bolt is an effective yielding device. It absorbs twenty times more impulsive-load energy than is consumed by the complete fracture of grouted re-bar of equivalent strength, and it remains totally unscathed. Importantly, the results demonstrate that the ejection model is not merely an explanatory concept, but can be used as a representative and valid design method.

Jan 1, 1994

By A. A. Bradley, P. J. D. Lloyd, A. J. Freemantle

Developments in centrifugal milling by A. A. BRADLEY,B.Sc. (Rhodes) (Visitor), A. J. FREEMANTLE, B.Sc. Hons. (Wits) (Visitor), and P. J. D. LLOYD, B.Sc. (Chem. Eng.), Ph.D. (Cape) (Fellow) The theoretical and experimental results of a study of centrifugalmills are reviewed. Means for the scaling up of such mills are suggested, and tests on a prototype mill are described. Despite the high lining wear in the centrifugal machine, which reduces its productive availability, its other advantages suggest that there is merit in pursuing its further development.

Jan 6, 1974

By G. W. Holl, E. G. Fairon

A review of some aspects of shaft design by G. W. HOLL, Pr. Eng., Associate of the Mine Managers Association of South Africa (Fellow)- and E. G. FAIRON, Pr. Eng., F.S.A.I.E.E., M.I. Cert. M.E.E., M.I.Mech. E., (Visitor) The reasons for the choice of vertical shafts in preference to inclined shafts of comparable capacity are set out, and the conclusion that the former are superior in virtually all circumstances is substantiated. The shapes of vertical shafts sunk during the past sixty years are recorded, and the shapes of those sunk during the past decade are analysed. From this analysis it is clear that circular and elliptical (and quasi-elliptical) shafts are the shafts of the future and that the rectangular shape will conceivably become obsolete. The determination of the size of shaft is discussed and it is forecast that shafts of a diameter of 13 metres and over will probably be sunk without difficulty in the years to come. The depth of the shaft is determined intrinsically by the Mines and Works Regulations applicable to factors pf safety of winding ropes and the design of the winding system. The Blair winder is the most suitable winder for hoisting rock, men, and material from a depth of, say, 3000 metres on an economic basis. Tertiary shafts will, therefore, be unnecessary in future deep-level mining projects at the limit of depth now envisaged. A few other factors relating to shaft design are described.

By G. R. Lane

My opportunity to serve as President of the prestigious Southern African Institute of Mining and Metallurgy (SAIMM) was made possible by an Anglo American scholarship 39 years ago—a pivotal moment that set me on a career path spanning various roles and start-up ventures in the mining industry. Over the past decade, I have been privileged to broaden my experience by consulting across diverse industries globally. This exposure revealed something profound: what I had previously considered mining-specific challenges are, in fact, universal across many sectors. At its core, a mining operation is a complex system of interconnected activities—from exploration through mining operations like drill and blast, load and haul, to beneficiation, and outbound logistics. My cross-industry work has clearly shown that diverse sectors, such as chocolate manufacturing, tissue paper production, toilet paper converting facilities, labgrown diamonds, or high-tech equipment lifecycle management, all rely on value streams of interconnected activities to transform products. The objective is to maximise throughput while effectively managing performance variability. The primary difference lies solely in the specific technical expertise required for each industry, such as chemical, mining, processing, or metallurgical engineering. Across all these industries, I have observed a consistent pattern, that is, performance is primarily driven by individual efforts, where people react and work diligently as situations unfold in real-time. General managers and their teams often operate tactically, focusing on explaining yesterday’s poor performance rather than proactively setting up operations for success. This often resembles an ‘‘under-7s soccer match’’, with everyone chasing the ball. The common response to issues is to add more ad hoc meetings. This effort-driven organisational behaviour persists regardless of whether operations are greenfield digital manufacturing facilities, advanced digital mines with advanced process control, or operations run on paper and Excel spreadsheets for data acquisition. Paradoxically, more real-time data can lead to increased data noise, greater indecision, and sometimes, lower performance. Despite value streams often operating significantly below capacity, organisations continue to invest heavily in additional equipment or in ‘‘glossy brochure promises’’ of Industry 4.0 digital technology and real-time data solutions, which frequently fail to deliver value. This leads to a critical question: Have we underinvested in our most valuable resource— people? Even Tesla faced this challenge with their underperforming fully automated Model X facility. We must shift our focus to designing the ecosystem, or operating model, of our organisations. This extends beyond the traditional triad of people, process, and technology, and moves beyond simplistic views of change management. Artificial Intelligence (AI) has the potential to add significant value, but it also introduces another layer of complexity into designing the organisation of the future. My full presidential address below at the SAIMM AGM discussed the symptoms of an effort-driven organisation and covered the fundamental building blocks and requirements of an operating model, including recommendations on implementing a people-centric approach.

Oct 2, 2025

By H. Ruthert

An understanding of wear in systems conveying solids is extremely important from the standpoints of design and economics. The lifetime of any bulk solids-handling system depends on the type of solids present and the operating parameters of the transportation system. The relationship between wear in backfill pipelines on South African gold mines and the transportation system's operating parameters is well understood. However, the effect of the transported solids on the pipe wear is less well understood, because of an inability to characterize particle sharpness. The sharpness of the particles, together with their size and hardness, is responsible for the aggressivity of particles, or their ability to cause damage and wear. This paper presents a novel method for the characterization of particle sharpness. The results presented rank particles according to the sharpness of their surfaces.

Jan 1, 1993

By H. T. Kaiser, P. De Waal

The Alusaf aluminium smelter at Richards Bay by H. T. KAISER, B.Sc. (Pta), M.B.L. (Unisa) (Visitor) and P. DE WAAL, B.Sc., B.lng. (Mech.) (Stell.) (Visitor) A description is given of the aluminium smelter at Richards Bay, which operates on the Hall-Heroult electrolysis principle. The annual output of metal (average 99,7 per cent aluminium) is approximately 7S 000 tons. Since its commissioning in 1971, the plant has fulfilled South Africa's total demand for low-alloy rolling slabs, extrusion billets, remelt ingots, and electrical conductor rod. The plant layout allows for sufficient expansion of its capacity to meet longterm increases in demand.

Jan 7, 1977

Council and Standing Committees, 1977-1978 President: P. A. von Wielligh. Vice-Presidents: Dr M. G. Atmore and D. A. Viljoen. Honorary Treasurer: J. K. E. Douglas. Immediate Past President, Dr M. D. G. Salamon. Members of Council: J. D. Austin, A. N. Brown, A. A. Hazell, Dr P. R. Jochens, Prof. R. P. King, Dr D. G. Krige, Prof. F. Q. P. Leiding, D. G. Malan, J. C. Mostert, H. G. M. Rose, W. T. Ruhmer, A. A. Sealey, R. A. von Maltitz. Chairman, Witbank-Middelburg Branch: T. S. Wilmot. Chairman, Orange Free State-Klerksdorp Branch: A. N. Shand. Past Presidents Serving on Council: R. J. Adamson, H. Britten, J. K. E. Douglas, Prof. D. D. Howat, Dr J. P. Hugo, D. G. Maxwell, Prof. R. P. Plowman, Dr R. E. Robinson, P. W. J. van Rensburg. Standing Committee Chairmen: Membership, D. A. Vil¬joen; Technical Programme - Metallurgy, Dr P. R. Jochens ; Technical Programme - Mining, Dr D. K. Krige ; Vacation School - Metallurgy, Prof. R. P. King ; Vacation School - Mining, Dr M. D. G. Salamon; Awards, Dr M. D. G. Salamon; Excursions, Dr M. G. Atmore; Adjudication, Dr M. D. G. Salamon; Consti¬tution, Rules, and Policy, Dr M. D. G. Salamon; Mines and Works, P. A. von Wielligh ; Education, Dr M. D. G. Salamon; Monograph Series, Dr R. E. Robinson; Phoenix National Committee, Dr R. E. Robinson ; Pyrometallurgical Discussion Group Convenor, Dr J. B. See/Dr D. I. Ossin.

Jan 1, 1979

The Institute of Lighting Engineers of South Africa The Institute of Lighting Engineers of South Africa (ILESA) was constituted in May 1972 and now has over 70 members. The first Annual General Meeting was held on 15th August, 1973, at the Philips Auditorium, when the first presentation of membership certificates was made. Book Reviews Der Hochofenprozess. Das kinetischdynamische Simulationsmodell des Vereins Deutscher Eisenhiittenleute.Diisseldorf, Verlag Stahleisen M.B.H., 1973. Jones, M. H. and Woodcock, J. T. Ultraviolet spectrophotometry of flotation agents with special reference to the determination of xanthate in flotation liquors. London, Institution of Mining and Metallurgy. 1973. 25 pp. £2,50. Notice VI INTERNATIONAL CONGRESS OF ENGINEERS The above congress is to be held in Barcelona from 6th to 10th October, 1974. NIM reports Report No. 1568 A computer programme for the estimation of parameters in flotation. Report No. 1571 The commissioning of a direct-reading spectrometer for the analysis of silicate rocks by use of the graphite-pellet technique. Report No. 1579 The determination of tin tn geochemical- survey samples. Report No. 1587 A preliminary investigation of the flotation of copper-activated sphalerite without the use of collectors. Report No. 1589 Preliminary investigations into the flotation of tin dioxide, cassiterite, and some related gangue minerals. Professional . engineers Reference (18/19/1) 22nd November, 1973 Dear Sir/Madam, From time to time questions are being asked publicly concerning registration of professional engineers. These questions mainly concern the time it takes to finalise applications, especially those of applicants who do not hold a recognised engineering qualification. Professionele . . Ingenleors Verwysing (18/19/1) 22 November 1973 Geagte heer/dame, Van tyd tot tyd word daar vrae in die openbaar gestel oor die registrasie van Professionele Ingenieurs. Vrae gaan veral oor waarom dit so lank neem om aansoeke af te handel, veral van aansoekers wat nie 'n erkende ingenieurskwalifikasie besit nie.

Jan 3, 1974

By R. S. Francis

There are no manuals or handbooks for budding mill superintendents or process plant managers. Most who obtain this level of responsibility have gained their training from watching the good and bad of their predecessors and the successful ones have themselves graduated from the school of hard knocks. This paper attempts to provide some helpful guidelines and direction for those who aspire to better manage a mineral processing facility. The authors have 20 years combined experience in senior management roles at nine different mineral processing operations in Australia and overseas, covering gold, base metals and mineral sands. This summary of tips and pitfalls will hopefully benefit future leaders in mineral processing and metallurgy.

Jan 1, 2007

COUNCIL AND STANDING COMMITTEES - 1973-1974 Office Bearers: P. W. J. van Rensburg (President), Professor R. P. Plewman and Dr R. E. Robinson (Vice Presidents), J. K. E. Douglas (Honorary Treasurer), and Dr J. P. Hugo (Immediate Past President). Elected Members of Council: Dr M. G. Atmore, G. H. Grange, Dr P. R. Jochens, J. G. Kirchner, Dr D. I. Legge, W. W. Malan, Dr M. D. G. Salamon, L. W. P. van den Bosch, D. A. Viljoen, P. A. von Wielligh. Branch Chairmen: B. T. Hosking (Witbank-Middelburg Branch), E. T. Wilson (Orange Free State Branch). Past Presidents Serving on Council: R. J. Adamson, M. Barcza, H. Britten, H. E. Cross, Professor J. de V. Lambrechts, R. C. J. Goode, Professor D. D. Howat, D. M. Jamieson, D. G. Maxwell, Dr J. T. McIntyre, V. C. Robinson. Ten Council meetings were held during the year, with an average attendance of 19, and the standing committees held 30 meetings. COMMITTEE CHAIRMEN Membership, Dr R. E. Robinson ; Metallurgical Colloquia, Dr R. E. Robinson ; Mining Colloquia, L. W. P. van den Bosch; Awards, P. W. J. van Rensburg; Excursions, P. A. von Wielligh; Dinner, G. H. Grange ; Constitution, Rules and Policy, Dr J. P. Hugo; Adjudicating, P. W. J. van Rensburg; Mines and Works, W. W. Malan; Education, Dr J. P. Hugo. REPRESENTATIVES ON OTHER BODIES Associated Scientific and Technical Societies: Members : V. C. Robinson and D. G. Maxwell Alternates : P. W. J. van Rensburg and Dr J. P. Hugo. Federation of Societies of Professional Engineers Members : J. K. E. Douglas and P. W. J. van Rensburg Alternates : Dr J. P. Hugo and G. H. Grange. South African Council for Professional Engineers Members : R. C. J. Goode and J. K. E. Douglas Alternates: G. H. Grange and Dr R. E. Robinson. Engineers' Liaison Committee (Pretoria): Member: Professor J. de V. Lambrechts Alternate : Dr J. P. Hugo. MEMBERSHIP Seventeen Fellows and Members, twenty-three Graduates, ten Associate Members, twenty-two Associates, thirty-four Students, and seven Company Affiliates were elected during the year. Eleven Fellows and four Members were admitted to retired membership. Five Fellows were elected to Honorary Life Membership. Four Members, two Graduates, and one Student were transferred to Fellows ; eleven Graduates and Students were transferred to Members ; eight Students to Graduates; and four Students to Associates. A statement of membership as at June 30th 1974 and the end of the previous year is given in the following tabulation 30th - 30th June, - June, 1973 - 1974 Honorary Life Fellows 4 - 9 Honorary Fellows 9 - 8 Life Fellows 177 - 170 Fellows 536 - 544 Members 487 - 512 Associate Members - - 10 Graduates 128 - 130 Associates 186 - 194 Students 183 - 173 Company Affiliates 64 - 70 1 774 - 1 820 OBITUARIES Your Council records with deep regret the death during the year of the following members : Dr P. N. Lategan and Dr O. A. Jackson, Honorary Life Fellows and Past Presidents; C. Airth, T. L. Blunt, J. B. Dennison, A. E. Frazer, C. L. Lamb, V. O. Reid, K. Richardson and D. G. Roberts, Life Fellows ; H. F. Allan, J. T. Beaumont, M. Eisenstein, J. C. Hall, C. F. Louw, H. H. McGregor, R. Murchison, and J. E. Williamson, Fellows; and R. B. Miles, Associate. FINANCE The annual accounts, which follow this report, reflect a healthy position and show that measures taken by Council over the last few years to boost income have been successful. A higher income was needed not only to meet rising costs but also so that the services provided by the Institute for its members could be expanded. This year's income of R55 025 showed a further increase compared with last year's figure of R48 307. Income from subscriptions was higher mainly owing to an increased number of Company Affiliates, and this is indicative of the support given by mining and metallurgical companies to the good work being done by the Institute. Further sales of publications of the symposia held over the last few years again made a useful contribution to income of R4560. The first Winter School held in 1973 yielded a surplus of R7495 after the expenses had been deducted from the income received from registration fees. The cost of administering the Institute increased by R2212 compared with the previous year. Included in this was a donation of R1000 to the A.S. & T.S. Trust Fund. The cost of publishing and printing the Journal increased by R2034, but advertising and extraneous sales of the Journal were higher, with the result that the net cost of the

Jan 10, 1974

By F. L. D. Cloete, A. K. Haines, T. D. Sampson, T. H. Tunley, W. A. M. te Riele

The recovery of zinc from pickle liquors by ion exchange A. K. HAINES. Ph.D. (Visitor) T. H. TUNLEY. B.Sc;.(Chem.Eng.)(Visitor), W. A. M. TE RIELE. pr, Eng.. Ph. D. (Visitor), F. L. D. CLOETE. M.Sc. (Chem..Eng.)(Visitor), and T. P. SAMPSON. Pr. Eng.. BSc, (Chem.Eng,). B. Econ. (Visitor) Picklers and galvanizers in and around Johannesburg are encountering an ever-increasing problem in disposing of spent liquors from their hydrochloric acid pickling baths. Particularly troublesome is the zinc-contaminated liquor that is produced as a result of the clean-up of rejects from the galvanizing operation. Because of the volatility of zinc chloride. this liquor presents difficulties when processed in a conventional pyrohydrolysis acid-recovery unit. The paper describes the Metsep Process. developed by the National Institute for Metallurgy and Woodall-Duckham S.A. (Pty) Ltd. which involves the use of continuous ion exchange for the separation of the zinc from the pickle liquor. and the use of liquid-liquid extraction for the conversion of zinc chloride eluate to salable zinc sulphate. A description of laboratory and pilot-plant tests is given. and the approach used in the design of a full-scale continuous- ionexchange plant is outlined.

Jan 11, 1973

By D. Limpitlaw, A. Alsum, D. Neale

"Ecological footprint analysis (EFA) was first described in 1996 as a measure of carrying capacity appropriated by human activities. EFA is a resource and emissions accounting tool designed to track the demand on the biosphere’s regenerative capacity. Ecological footprints are increasingly used as indicators of organizational and corporate environmental performance and product sustainability. There is a compelling argument to develop an EFA tool for mining companies.To determine the size of a mine’s ecological footprint, land requirements for all categories of consumption and waste discharge must be summed. This land is only made up of the ecologically productive land and water in various classes (cropland, pasture, forests etc.) required on an ongoing basis to provide all energy and material resources consumed and absorb wastes.A challenge in conducting an EFA for a mine is the shortage of accessible data. Undertaking an EFA for a corporation or individual site entails compiling consumption and emissions data (which can be used for other reporting applications). The footprint results themselves highlight the most critical aspects of an organization’s impact on the environment and provide a platform for focusing actions and for educating the workforce to improve their contribution to best-practice operations. This paper discusses the benefits and challenges of undertaking an EFA for a mining company, and provides examples of the various components of ecological footprints associated with mines, as well as showing how an EFA can be used to understand and communicate some of the impacts associated with mining activities.IntroductionFundamental biophysical and economic limits are now being experienced in many countries around the world. Herman Daly, a former World Bank economist, described this scenario as ‘uneconomic growth’, where the costs of growth exceed the benefits (Daly, 2005). This occurs when the economy’s expansion encroaches excessively on the surrounding ecosystem, sacrificing natural capital. Under such conditions the sacrificed natural capital is more valuable that the resulting economic growth. Consequently, the world faces largescale threats to sustainability and especially to the viability and continued existence of the ecosystems that support human settlements (El Zein et al., 2014). In recognition of this sustainability imperative, mining companies are increasingly concerned with their ecological footprint (EF)."

Jan 1, 2017

Council and Standing Committees, 1975-1976 President: Dr R. E. Robinson. Vice-Presidents: Dr M. D. G. Salamon and P. A. von Wielligh. Honorary Treasurer: J. K. E. Douglas. Immediate Past President: Prof. R. P. Plewman. Members of Council: Dr M. G. Atmore, J. D. Austin, C. T. Fenton, J. A. Holmes, P. Holz, Dr P. R. Jochens, Prof. R. P. King, Dr D. G. Krige, Dr D. I. Legge, D. G. Malan, C. T. Shaw, D. A. Viljoen, R. A. von Maltitz, H. M. Wells. Chairman, Witbank-Middelburg Branch: E. J. Jackson. Chairman, Orange Free State Branch : G. J. C. Young. Past Presidents Serving on Council: R. J. Adamson, H. Britten, H. E. Cross, J. K. E. Douglas, R. C. J. Goode, Prof. D. D. Howat, Dr J. P. Hugo, D. M. Jamieson, D. G. Maxwell, Dr J. T. McIntyre, V. C. Robinson, P. W. J. van Rensburg. Seven Council meetings and five Executive Committee meetings were held during the year, and the standing and sub-committees held fifty-five meetings. Standing Committee Chairmen Membership, P. A. von Wielligh ; Technical Programme-Metallurgy, D. A. Viljoen; Technical Programme-Mining, D. G. Malan; Vacation School-Metallurgy, Dr P. R. Jochens ; Vacation School-Mining, H. M. Wells; Awards, Dr R. E. Robinson; Excursions, Dr D. I. Legge; Adjudicating, Dr R. E. Robinson; Constitution, Rules and Policy, Prof. R. P. Plowman; Mines and Works, C. T. Shaw; Education, Prof. R. P. Plewman; Foundry Colloquia, Prof. D. D. Howat. Representatives on Other Bodies Associated Scientific and Technical Societies: Members : Dr R. E. Robinson and Prof. R. P. Plewman. Alternates : P. A. von Wielligh and Dr M. D. G. Salamon. Federation of Societies of Professional Engineers: Members : J. K. E. Douglas and Prof. R. P. Plewman. Alternates: Dr R. E. Robinson and Dr M. D. G. Salamon. FSPE Technicians Committee: Member: D. M. Jamieson. FSPE Rationalziation Committee: Member: Dr M. D. G. Salamon. South African Council for Professional Engineers (Institute Nominees) Member : R. C. J. Goode. Alternate: G. H. Grange. South African National Committee on Tunnelling: Member : D. G. Malan. Alternate: Prof. R. P. Plewman. Engineers' Liaison Committee (Pretoria) Member : Dr J. P. Hugo. Alternate : P. W. J. van Rensburg. Government Certificate of Competency Liaison Committee: Member: Prof. R. P. Plowman. Alternate: D. M. Jamieson. James Moir Memorial Lectures: Member : Prof. D. D. Howat. World Mining Congress-National Committee: Members : Dr M. D. G. Salamon, Prof. R. P. Plewman, and H. M. Wells. I.F.A.C. Symposium: Member: P. W. J. van Rensburg (Chairman-Organising Committee). Alternate : Dr J. P. Hugo. I. U.P.A.C. Symposium: Member: Dr P. R. Jochens. Membership Nine Fellows, twenty Members, six Associate Members, thirteen Graduates, nine Associates, twenty-nine Students, and ten Company Affiliates were elected during the year. One Fellow was elected to Honorary Life Fellowship, eight Members and one Graduate were transferred to Fellows, twelve Graduates and two Students were transferred to Members, three Students were transferred to Graduates, and one Student was transferred to the grade of Associate. Six Fellows, two Members, and two Associates were admitted to retired membership. Nine Fellows, fifteen Members, three Graduates, one Associate, two Students, and one Company Affiliate resigned. A statement of membership as at June 30th, 1976, and the end of the previous year is shown in the following tabulation. 30th June, - 30th June, 1975 1976 Honorary Life Fellows 16 - 17 Honorary Fellows 8 - 8 Life Fellows 171 - 171 Fellows 549 - 547 Members 523 - 517 Associate Members 15 - 21 Graduates 132 - 123 Associates 209 - 205 Students 173 - 179 Company Affiliates 71 - 80 1866 -1878 Obituaries Your Council records with deep regret the death during the year of the following members: P. A. Creewell, Life Fellow; A. S. Davis, J. S. Hay, P. 0. Lange, N.

Jan 10, 1976

The mathematical models of semivariograms can be classified according to whether or not they correspond to situations where the second order stationarity conditions are satisfied (§ 3.3.4). If second order stationarity exists, the a priori variance s2 of x (z) also exists and is finite. For large distances h such that x (z) and x (z + h) are not correlated, the semi- variogram ? (h) will reach a value equal to s2 [this is a consequence of (3.27) above]. This limiting value is called the sill C of the semivariogram, and the distance at which ? (h) reaches the sill is called the range. The range of the semi- variogram obtained from a given type of sample corresponds to the distance of influence of these samples. If only the intrinsic hypothesis is satisfied, the sample variance is an increasing function of the size of the area or volume in which the samples are located, and the semivariogram ? (h) will be a continuously increasing function of h. Remark: It will be shown in Chapter 7 that the variance s2 of x (z) in the ore body O is equal to the average value of ? (h) in O. If ? (h) is a non-decreasing function with sill C, the average value of ? (h) in O will be less than C. s2 and C will be equal only if for some values of h in O, ? (h) exceeds C. In practice, if the range of the semivariogram is small with respect to the dimensions of the ore body, the difference between C and s2 will be negligible.

Jan 1, 1978

By H. Moslemi

Metal sulphides are usually semiconductor and their electrical conductivity is low; therefore they are sources of electrons and promote electrochemical reactions. This phenomenon is of significant importance in sulphide flotation. The formation of a hydrophobic surface on the sulphide minerals is the result of various electrochemical reactions. Potential difference in the mineral-liquid interface plays an important role in the kinetics of the reactions, and consequently, on the flotation behaviour of sulphides. The value of the potential difference is influenced by different oxidation-reduction reactions at the interface area, and is measured by a two-electrode system in which an electrode is applied as reference electrode. In this study, we attempted to measure open-circuit potentials of pyrite, pyrrhotite, and steel electrodes with respect to the reference electrode. To verify the results, two reference electrodes, saturated calomel and gold, were used. Time-potential relations with respect to both reference electrodes show that the potential of both pyrite and pyrrhotite increases with time; however, this trend decreases for steel except when at pH 12. The results show a potential drop by an increase in pH value, except for steel, for which the opposite holds. This paper discusses galvanic interactions between minerals and grinding media in the grinding circuits, as well as among other minerals in the flotation processes.

Jan 1, 2012

This International Mine-Surveying Conference will take place in Budapest (Hungary) from 5 to 14 June, 1972. Detailed information can be obtained from the Mine-Surveying Working Committee of the Hungarian Mining and Metallurgical Society. Write: OMBKE Bányaméröi Munkabizottsag Budapest, V., Szabadsag ter 17, Hungary. SYMPOSIUM ON NICKEL The 'Gesellschaft Deutscher Metallhiitten-und Berglaute' is holding a Symposium on nickel on 24-25 September, 1970 at Wiesbaden, on the occasion of the G.D.M.B. Annual Meeting. Some 24 papers will be presented by metallurgists from many important companies around the world. Information may be obtained from The Secretary, G.D.M.B., Postfach 210, 03392 Clausthal-Zellerfeld, German Federal Republic. VISIT TO THE COUNCIL FOR SCIENTIFIC AND INDUSTRIAL RESEARCH On 23rd June, 1970, members of the Institute visited the C.S.I.R. in Pretoria. More members had booked for this tour but the current flu epidemic caused cancellations which was unfortunate. The visit was organised with military precision, which prevented detailed discussion of any particular subject, but provided a bird's eye view of a large number of interesting projects. The visit was packed with interest for all and those requiring further information were invited to contact the relevant divisions afterwards. Or Denkhaus welcomed the delegates and stressed the importance of integrating research efforts with industry's requirements. An excellent colour and sound film was shown which depicted the work of the Rock Mechanics division. This showed very clearly methods used for preparing rock samples and demonstrated the machines and instruments for the various tests. It made one realise the extent to which this research has been integrated with the actual mining situation. The fullscale experiments underground showed the failure of pillars under applied loads and were very interesting. This is undoubtedly a film which all mining people should see. After the film the rock mechanics laboratories were visited where the actual machines were seen and described. We then visited the metal and strength mechanics sections where the metallurgists were able to see some interesting experiments and tests. We also visited the Aeronautics Research group where a large 1 000 hp wind tunnel was inspected. We were told enough about this to realise something of the complexities involved in the design and operation of a closed circuit tunnel of this type. The tunnel is used for tests on models which are necessary for the design and modification of aircraft. After a very excellent lunch at the C.S.I.R. recreation centre, the delegates attended two lectures-one by Mr. Mandersloot of the Chemical Engineering group, who outlined the varied functions of this group and told us something of their work. Of particular interest was the research into the suitability of various South African manganese ores for dry cell batteries. Work on the thickener settlement studies interested the metallurgists. The second lecture was given by Mr Donaldson of the National Building Research Institute. This Institute has about ten divisions each of which covers a particular aspect of building research. The work of the soil mechanics division was described in detail and illustrated by coloured slides. This was particularly interesting and demonstrated clearly how building failures result from lack of attention to detail of construction where unstable soil conditions exist. Cracks in walls of compound blocks brought the subject home forcibly to the mining delegates. This division has also caried out important work on sinkholes and sUmes dams and produced some positive results. Altogether the visit was most interesting and enjoyable. It was made more worthwhile because the emphasis was on the work being carried out and not on just seeing the laboratories. The Institute is greatly indebted to the C.S.I.R. and its staff for the very excellent arrangements made.

By T. Mahlangu Mahlangu, T. Fungene, K. C. Sole

"Although oxygen is widely employed as the oxidant of choice in gold leaching by cyanide, its low aqueous solubility presents some drawbacks in practical application; hydrogen peroxide has therefore been considered as a possible alternative. The aim of this investigation was to study the catalytic decomposition of hydrogen peroxide, which generates an oxidizing intermediate species, and to understand its effect on cyanide destruction. Operating conditions that facilitated the effective decomposition of hydrogen peroxide were established by varying the pH and catalyst type and concentration. The oxidizing intermediate, detected using an indirect technique, was found to be the hydroxyl radical (OH?). OH? is commonly generated in acidic solutions, but this work demonstrated that it is also produced at the alkaline pH values necessary for cyanide gold leaching. The effects of free and complexed iron and copper catalysts on the oxidation and consumption of hydrogen peroxide and cyanide were also investigated. It was shown that the cyano complexes of Fe(II) and Cu(I) are also effective as decomposition catalysts. Hydrogen peroxide concentrations above 0.01 M decreased the free cyanide concentration, which was attributed to the probable formation of the cyanate anion (CNO-). Although cyanide consumption increased due to its oxidation in the presence of OH?, excessive cyanide consumption in the presence of copper was attributed primarily to its complexation by the unstable copper(I) cyanide species. Rate constants for the decompositions of H2O2 and cyanide by ferrocyanide and copper cyanide were calculated; the latter was identified as being a better catalyst. IntroductionLeaching of gold from its ores using cyanide has been employed for well over a century (Habashi, 2016). Addition of cyanide converts the gold into a cyanide complex (Au(CN)2 -) that is soluble in water (Wang and Forssberg, 1990). The leaching reaction can be represented as Equation [1]:"

Dec 1, 2018

By S. Poirier, J. -M. Facteau

The gold mine sector is presently facing low gold prices as well as technological challenges. Its competitiveness and survival will depend on new mining methods and equipment to improve ore extraction. In 1999, Natural Resources Canada has invested new funds over a period of three years at CANMET’s Experimental Mine to establish the Narrow-Vein Mining Project. A team of engineers and researchers specialized in mining, mechanics and electronics engineering are working to meet the critical need of ore-extraction technology. CANMET’s programme in mechanization and automation for narrow-vein mining had, prior to 1999, realised several important achievements, many in co-operation with a consortium of mining companies(Soredem). The investment of new funds in this area will contribute to develop technologies to improve the productivity, as well as health and safety conditions of the narrow-vein mining industry. Several important impacts of this project will be monitored. In particular, a database of methods and equipment used in narrow-vein mining is being developed. A key thrust is to identify operators’ needs with respect to the development and automation of mining methods and equipment. Based on those needs, research and development projects will be created. The paper will present the objectives of the narrow-vein mining project and some of the results, including the web site developed to present the results of the project.

Sep 1, 2001

The Annual General Meeting of the South African Institute of Mining and Metallurgy was held in Kelvin House on Wednesday, 23rd August, 1978. Mr P. A. von Wielligh (President) was in the chair and declared the meeting open at 16h00. Obituaries The President: It is my sad duty to announce the death of the following members of the Institute : T. K. Prentice and W. E. Gooday, Honorary Life Fellows and Past Presidents; B. S. Allen, J. A. Becking, L. H. Mellor, C. A. Pratt and W. T. Stobart, Life Fellows; J. P. Burls, E. Cameron, M. L. Fitzgerald, C. G. Hinds, A. J. Patrick, H. O. Reisener, N. D. Shuttleworth, N. Soldan and J. Whitehouse, Fellows; T. Gemmell, J. S. A. Oelofse, W. D. Rowe, R. L. J. Shearman and G. M. Thain, Associates. As a mark of respect to the memory of the deceased and in sympathy with the bereaved, I ask you to rise and observe a few moments' silence. Welcome The President: It is now my very pleasant duty to welcome our distinguished guests and visitors. We are pleased to have with us Mr D. A. Etheredge, Vice¬President of the Chamber of Mines of South Africa, and Mrs Etheredge. Mr Etheredge this afternoon represents the mining industry at our meeting. The importance of the close link that over the years has been maintained between the industry and our Institute speaks for itself. We are, therefore, grateful that he and Mrs Etheredge have managed to find the time to be with us this after¬noon.

Jan 1, 1979

By S. Visage

By 1984 Iscor's first direct-reduction plant will be operating at the Vanderbijlpark Works, and for the fin;t time the Corporation will have an alternative method to the blast furnace for producing iron from ore. The performance of Iscor's four-kiln plant, which will be the largest coal-based plant in the world producing sponge iron, will undoubtedly be watched with great interest by steelmakers throughout the world. Beneficiation of tin The Southeast Asia Tin Research and Development (SEATRAD) Centre is a regional oganization, formed by the Governments of Indonesia, Malaysia, and Thailand with assistance from the United Nations, to conduct, coordinate, and promote research and training in the various fields of tin production, including geology, prospecting, mining, mineral processing, and smelting.

Jan 1, 1982