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By G. E. Blight

Several aspects of the behaviour and properties of backfills consisting of cemented cyclone underflow tailings are illustrated by means of examples, and guidelines are given on the optimization of the performance of cemented fills. The stretch characteristics of the geofabric used to contain freshly placed backfill are described, as well as the relationship between these characteristics and the forces acting on retaining barricades. The properties required to achieve a self-supporting, stable free face in cemented backfill are explored, and a graphic relationship between stable height and shear strength is presented and compared with that for uncemented (classified) tailings. After a description of the characteristics of Witwatersrand quartzite gold-tailings backfill and commonly used cements, the process of drainage and air entry into backfill is outlined. Following this, the early-age gain in strength and the shear-strength characteristics, as well as the compressibility characteristics of cemented backfill, are described. Two phenomena that are potentially damaging to cemented backfill are seismic effects (or blasting acceleration) and the closure that takes place during the curing of cement. Investigations show that neither of these phenomena is actually significantly deleterious to gold-tailings backfill: liquefaction does not Occur as a result of seismicity, and hydration of cemented fill is not significantly impeded by closure.

Jan 1, 1996

A powerful, interactive metallurgical process simulator for use on micro- computers has been developed in the Department of Metallurgy and Materials Engineering at the University of the Witwatersrand. MICROSIM presently allows simulation of all ore-dressing flowsheets and a selection of hydrometallurgical unit operations, and is extendable to all such processes. MICROSIM is written in Pascal. This modern language provides very versatile data structures which can be effectively used to solve the major problem in generalised simulation programs, namely storage and transmission of data relating to liquid and solid phases. Dynamic memory allocation allows optimal utilisation of computer storage space. The simulator utilises very efficient precalculation algorithms that determine the tear streams for optimal sequential modulator calculation convergence. Microcomputer graphics simplifies flowsheet specification, and form-filling data capture with supplied default values eliminate most common input errors.

Jan 1, 1987

By Mike Rogers

Platinum production in Southern Africa amounted to 80% of world production in 2005with a small increase from 5 117 000 ounces to 5 275 000 ounces. For the seventh consecutive year the platinum market is on course to record a moderate deficit in supply. This is reflected in the price increase from a trading range US$860 to US$880 in June 2005 to an excess of US$1 200 in September 2006. Southern Africa, with its extensive platinum reserves, will continue to be the dominant platinum producer and has a number of new mines in an advanced stage of planning. The slogan ?Platinum Surges Ahead? was selected to describe the exciting and vibrantnature of all aspects of platinum mining, beneficiation and marketing. This conference will cover these aspects from exploration and orebody delineation, through mine design, development and operation to mine closure; mineral beneficiation, marketing and compliance with the Mining Charter will also be subjects for discussion and debate. It is also anticipated that the issue of overall increases in productivity, through the introduction of technology, will demonstrate Southern Africa?s status as a premier mining district. It is my pleasure to welcome delegates from abroad and locally, on behalf of the SAIMM, to the Second International Platinum Conference ?Platinum Surges Ahead?. I trust that you will find the proceedings informative and value adding and will participate in the discussions and debate in order to obtain maximum benefit from the conference. I am sure that the post-conference tours will be interesting and of great benefit to participants. Finally, a big word of thanks to the members of the Organising Committee, the management and staff of the SAIMM, and to our willing sponsors, without all of whom this conference would not have been possible.

Jan 1, 2006

By R. Thomas

A Honeywell TDC 2000 central process control system was installed at Rössing in 1984. The system controls the metallurgical operations from crushing to the finished product of uranium oxide and manufacture of sulphuric acid. The operation was previously controlled from nine separate local control rooms. The paper briefly reviews the design and commissioning of the control system on an operating plant and discusses the impact on manpower organisation and training needs. Development of the process control system during its first two years of operation is reviewed and a summary is given of the current status of computer control at Rössing. The impact of the new system on overall plant operation and performance efficiency is also briefly described. In conclusion, future developments of computer control and overall optimisation of metallurgical operations are reviewed.

Jan 1, 1987

By J. R. Dixon

Gold mining has been undertaken in South Africa for more than a century. A great proportion of that mining has been from the Witwatersrand Basin; a geological phenomenon that has few parallels throughout the world. It has produced some 47 000 tonnes of gold mainly from underground mines, many of which have been truly world class gold mines. The gold mines of the Witwatersrand Basin have dominated world gold production from their inception and their production has been one of the cornerstones of the development of South Africa as a whole. The mines have some very specific characteristics; their sheer size, the depth of extraction, the nature of the orebodies, and their labour-intensive methods. The mines have also been part of the Mining House concept-a concept unique to South Africa. South African production has declined from a maximum of 1000 tonnes in 1970 to 470 tonnes in 1997. This, as a percentage of western world production, has declined from a maximum of 79 per cent (in 1970) to 21 per cent of world production (in 1997). The nineties' have seen South Africa and its mining companies move onto the world stage and face the harsh realities of having to compete in all spheres of business with their aggressive counterparts principally in Australia, Canada and the USA. The fight is for investment funds with the owners looking for the best returns on their money. In his address Roger Dixon will examine the current situation in the gold mining industry and examine the competitiveness of the mines of the Witwatersrand Basin compared with their peers worldwide. He will also discuss some of the fundamental challenges facing South African gold mines in the areas of legislation, technology, industrial relations, and health and safety. The environment in which the mines operate has changed radically in recent years and their ability to respond to these challenges will determine their future existence.

Jan 1, 1998

By G. R. Baiden

Introduction The introduction of teleremote systems to underground mining can provide a significant improvement in the performance of a mine when compared with conventional mining techniques. This paper presents the concepts of teleremote mining in a case study showing how the systems work and the competitive advantage autonomation of mining techniques will provide for underground metal mining operations into the future. This paper is divided into two sections: the Mining Automation Program and What is next? On January 1st 1996 Inco Limited, Tamrock Oy, DYNO Explosives Group and CANMET formed a consortium for the development of teleremote mining equipment called the ‘Mining Automation Program’ or MAP. This program included a five-year research and development agreement that combines the talents of the above organizations to create mining equipment and systems for autonomating mining. The projects are based on the communication system currently sold and marketed by Automated Mining Systems Limited. The main components of the program investigated the development of a positioning and navigation module, autonomated systems using teleremote techniques for development and stoping, and software systems to support the use of this equipment. The program included the establishment of a test mine, at Inco’s 175 Orebody near Copper Cliff North Mine. This facility was unique allowing collaboration of companies and research organizations inthe design and testing of techniques and equipment used to apply autonomation to mining. Since the inception of the project other research alliances have been added to enhance the program. These include the application of ground support (Meyco/ Master Builders), muck pile recognition, the broadening of telecommunications links (PRECARN Associates Inc.-MALTA project) and the collection and processing of drilling core through the automated diamond drilling project (J.K.S. Boyles). MAP began as an idea a number of years ago with the fundamental question ‘Can an ore-body be profitably mined through autonomation?’ The concept was to design mining equipment and systems that would allow the teleremote operation of a mine. Automation was only one componentof this much larger teleremote mining issue. To start with, it was essential to prove or disprove the feasibility of this concept. The fundamental requirements are: • Telecommunications • Positioning • Navigation • Equipment • Software • Electronics • Mining Engineering • Organization. Each of these had to be considered. Technically, the feasibility of the project hinged on the successful development of a high capacity communication network, an accurate underground positioning system, a navigation system and finally the electronics and software that could integrate these. Mining equipment that could perform all the mining functions was the next requirement, along with explosive supplies that could be delivered to the holes teleremotely. Whatever the systems developed, they must be able to work in both bulk and selective mining situations and in varying conditions within a mine. Finally, the organizational issues of a change from our current method of operation to teleremote mining had to be understood. After five years of research and development the answer to the question ‘Can an orebody be profitably mined using autonomation techniques?’ is YES! There are still hurdles to overcome, however, the basic premise has been proven. The development and production of underground tunnels and stopes has been done. There have been interesting outcomes in terms of reduced effort to accomplish mining and the total time to mine. Definitions •Automationis the process by which a machine or system is run continuously including the ability for the system to self-correct. •Autonomationis the same as automation except that the process does not self-correct. •Teleremote operation is the operation of mining equipment over a network from any location out of line-of-sight of the machine. •Equipment Automationis the addition of technology to a machine that allows for unmanned operation of a machine and thus enhances the productivity of the operator. For example, a guidance system that allows a load-haul-dump to drive by itself, thus freeing the operator for other tasks. •Teleremote mining describes a mine process that combines the use of teleremote operation (potentially with some automation), positioning and process engineering, monitoring and control. •Tamrock DataSoloTMis a computerized drilling rig as shown in Figure 1. •Tamrock DataMini™ is a computerized development drill rig used for drifting and construction tunneling as shown in Figure 2.•Tamrock Toro 450™ is a LHD (Figure 3).

Sep 1, 2001

1. Mining directory The mining directory, 1990. Mines and mining equipment companies worldwide. Don Nelson Publications Limited (P.O. Box 193, Barnet, Herts EN4 BLP, England).2. Mintek reports The following reports are available from Mintek, Private Bag X3015, Randburg, 2125 South Africa. They are available at R25 (plus R3,25 GST) per copy to South African addressees, and US$25 per copy (including airmail postage) to addressees elsewhere. There is also an annual-subscription scheme for reports - R400 locally (plus R52 GST) and US$400 (including airmail postage) abroad. The subscription covers al the unrestricted reports published between 1st April and 31st March of successive years, which usualy amount to between 20 and 30. Report M392 Computer programs for optimization by the modified simplex method, by G.L. Moore. Sep. 1989. 25 pp. R25 + R3,25 GST in South Africa; US $25 elsewhere. Report M393 The preparation and certification of fourteen South African silicate rocks for use as reference materials, by E.J. Ring. Sep. 1989.21 pp. R25 + R3,25 GST in South Africa; US $25 elsewhere. Report M395 The separation of trace elements in high-purity rhodium and iridium materials, by R.V.D. Robet and S.M. Graham. Nov. 1989. 10 pp. R25 + R3,25 GST in South Africa; US $25 elsewhere. 3. Publications from Trans Tech The publications listed in this section are available at the prices given from Trans Tech Publications, P .0. Box 1254, D-3392 Clausthal-Zelerfeld, West Germany. Handling of bulk solids. Theory and practice, by P.A. Shamlou. 1988. 200 pp., US$ 59.50. Acoustic emission lmicroseismic activity in geologic structures and materials, by H.R. Hardy and F.W'. Leighton. Vol. I: 1977, 490 pp., US$45.00. Vol. 11: 1980, 500 pp., US$45.00. Vol. Il: 1983, 680pp., US$6O.00. Vol. IV: 1989, 720pp., US$ 75.00. Open pit mine design models. An introduction with FORTRANI77 programs, by E. Alaphia Wright. Early 1990, approx. 200pp., US$75.00. Bucket wheel excavator, by W. Durst and W. Vogt. 988, 450pp., US$118.00. Continuois-surjace mining, by T.S. Golosinski and F.G. Boehm (eds.). 1987, 720pp., US$128.00. Mining-science and technology. 1987, 1430pages, US$ 118.00. Practical handbook for underground rock mechanics, by T.R. Stacey and C.H. Page. 1986, 150pp., US$ 38.00. Professional users handbook for rock bolting, by B. Stilborg. 1986, 150pp., US$38.00. The lighting of underground mines, by D.A. Troter. 1982, 220pp., US$48.00. Elements of hydraulic coal mine design, by M.L. Jeremic. 1982, 16Opp., US$38.00. Continuum theory of rock mechanics, by Cs. Assonyi and R. Richter. 1979, 365 pp., US$ 58.00. Shear and bond in reinforced concrete, by G. Florin.1980, 86 pp., US$ 24.00. Theory and design of surface structures: slabs and plates, by G. Florin. 1980, 222 pp., US$ 24.00. Mineral processing laboratory manual, by A.-Z. Abouzeid. January 1990, approx. 200pp., US$48.00. Weighing and proportioning of bulk solids, by Hendrik Colijn. 2nd ed. 1983, 4OOpp., US$60.00. Solid-liquid flow. Slurry pipeline transportation, E.J. Wasp et al. 1977, 240pp. US$ 58.00. Optimum pipe size selection, by C.B. Nolte. 1978, 304 pp., US$ 60.00.Field instrumentation in geotechnical engineering, T.H. Hanna. 1985, 854pp., US$98.00. The 1990 yearbook and directory. Powder and bulk solids handling and processing. 1989/90, approx. 300 pp., US$ 124.00.

Jan 1, 1990

1. Book reviews Perspectives in metallurgical development. London, The Metals Society. 338 pp. £29. Reviewer: John V. Bee Mechanics of oil shale, edited by K.P. Chong and J.W. Smith. London, Elsevier Applied Science Publishers Ltd, 1984. 603 pp. £75. Reviewer: R.W.O. Kersten 2. Recent publications CANADIAN MINERAL POLICY SECTOR. Metallurgical works in Canada. Primary iron and steel 1984. Mineral Bulletin MR 203. Ottawa, Canadian Government Publishing Centre, Supply and Services, 1985. $6.00. Tin and its uses no. 143. Greenford (England), International Tin Research Institute, 1985. Mining 1985, edited by Diana Russell. Harlow England), Longman Group Ltd, 1985. 540 pp. £46. The following books are available from CRC Press, Inc., 2000 Corporate Boulevard N.W., Boca Raton, Florida 33431, U.S.A. Inorganic ion exchange materials, edited by A. Clearfield. 304 pp. $100. Polyurethane foam sorbents in separation science, by T. Braun. $80. Advanced particulate morphology: theory and practice, by J.K. Beddow and T.P. Melloy. 208 pp. $79. CRC handbook of atomic absorption analysis, edited by A. Varma. 2 vols: vol. I $114, vol 11 $102. CRC handbooks of inorganic elecrochemistry, edited byL. Meites, P. Zuman, E.B. Rupp, andA. Narayanan. 3. Mintek reports Report M169 The preparation of three South African coals for as reference materials. Report M190 The preparation and certification of a South African phosphate concentrate for use as a reference material. Report M191 The agglomeration of fine material for bacterial heap leaching. Report M197 A computer programme to monitor the performance of an X-ray-fluorescence spectrometer. Metallurgical award The 1984 Acta Metallurgica Gold Medal has been awarded to Professor John W. Christian of Oxford University. The medal is an international award that was established in 1974 to recognize outstanding ability and leadership in materials research. Proterozoic volcanic suites An international symposium will be held at the British Geological Survey, Keyworth, Nottingham, U.K., from 2nd to 5th April, 1986. Entitled 'Geochemistry and Mineralisation of Proterozoic Volcanic Suites', this special meeting of the Geological Society will discuss the geochemical evidence for the nature of volcanism during the Proterozoic. Powder metallurgy Every second year the International Powder Metallurgy Conference, the world's leading event in powder metallurgy, is organized and held alternately in North America and Eruope.

Jan 1, 1985

The June General Meeting of the Institute was held in Kelvin House, Johannesburg, on 18th June, 1969, at 4.30 p.m. Mr J. K. E. Douglas (Vice-President) was in the Chair. There were also present fourteen Members, Messrs R. J. Adamson, F. P. Bath, D. M. Jamieson, D. G. Maxwell, Dr J. T. McIntyre, and Mr P. W. J. van Rensburg (Council Members), Messrs B. F. Berry, A. F. Lee, J. E. van Leeuwen, G. G. Nicolson, N. F. Peverett, Dr A. G. Raper, Messrs E. R. Rudolph and H. R. Reid. Five Associate Members, Messrs T. D. Brown, M. R. Fuller-Good, J. S. Freer, Dr P. R. Jochens and Mr D. A. Viljoen. One Graduate, Mr P. G. Mrkusic. Five Students, Messrs N. A. Barcza, J. A. Cruise, R. P. W. Henrard, D. I. Ossin and J. C. M. Wethmar. Nine Visitors, Messrs M. Badenhorst, N. J. Bovey, H. H. Herold, Dr H. J. S. Kriek, Messrs M. S. Rennie, B. B. Segal, S. Selmer-Olsen, O. A. W. Strydom and B. Yates. Secretary, Mr D. C. Visser. Total present: Thirty-six. MINUTES The Vice-President: "May we confirm the minutes of the Monthly General Meetings held on 24th March, 16th April and 21st May, 1969 as published in the Journal?" Agreed. MEMBERSHIP The Vice-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: Members: Wilfred Desmond Morgan, Abraham Kriek. Associate Members: Rodger Neville Hampson, Robert Richard Booth Lodge. Graduates: Beverley Hugh Waiters, Gwynne Hugh Johnston. Students: Colin Edward Alvery, Peter Marthinus Haikes, Charles Aubrey Husband, John Nowell Randell, Frederick Johannes Jacobus Blaauw, Johannes Andries Breytenbach, Peter Vos, Frederik Hendrik Coetzee, Petrus Nicolaas Jacobus Smit, Patrick Alien Boardman, Robert Nelson Guest. "May I welcome the newly elected members to the Institute." (Applause.) ELECTION OF SCRUTINEERS FOR THE 1969-70 BALLOT FOR COUNCIL The Vice-President: "In terms of By-Law 9.4, I now call for nominations for scrutineers for the 1969-70 ballot for CounciL" P. W. J. van Rensborg: "I wish to nominate Messrs R. C. J. Goode, V. C. Robinson, J. K. E. Douglas, P. Lambooy, D. G. Maxwell, H. Britten and H. Simon as scrutineers."

The May General Meeting of the Institute was held in Kelvin House, Johannesburg, on 21st May, 1969, at 4.30 p.m. Mr J. K. E. Douglas (Vice-President) was in the Chair. There were also present twenty-two Members, including Messrs F. P. Bath, M. Bareza, A. R. C. Fowler, D. M. Jamieson, C. M. Mavrocordatos, D. G. Maxwell and J. A. Nixon (Council Members), Messrs T. Davidson, G. L. Diering, E. T. Dunstan, D. E. H. French, K. Hodgson, O. A. E. Jackson, A. F. Lee, A. Louw, D. L. Starkey, R. K. Wheeler and M. Youngworth. Four Associate Members including Messrs D. Blair Hook and G. R. Still. One Student Mr N. A. Barcza. Thirteen Visitors, including Messrs S. H. Ash, D. L. G. Bayne, E. Bayne, S. Bell, W. S. Garrett, L. S. Gibbs, R. C. Hamilton, M. Maguire, D. Rose and J. D. van Niekerk. Total Present: Fourty-one. OBITUARY The Vice-President: "It is my sad duty to announce the death of the following member of the Institute: Thomas Spence Haldane, Member, who joined the Institute in 1924 and passed away on 21st December, 1968. As a mark of respect to the memory of the deceased and in sympathy with the bereaved, those present stood and observed silence for a few moments. MINUTES The Vice-President requested that confirmation of the minutes of the previous meeting be held over as they would only be appearing in the Journal of the following month. He also requested that confirmation of the minutes of the 75th Anniversary Meeting be held over. MEMBERSHIP The Vice-President: "I have much pleasure in announcing that the names of the under-mentioned candidates have been published in accordance with By-Law 5.2.2, and Council has elected them to membership of the Institute in the following grades: Members: Gideon Jacob Haumann, Peter John Cumming, Ian Stanley Dudman, Roderick Goldston Murchison. Associate Members: Francois Alwyn Beyers Fouche, Alan Marsh, Johannes Petrus van der Westhuysen, Waldo Edmund Stumpf, Ian Nicholas Ridley. Affiliates: Lutgerus Kolver Jooste, Roger Ainsley Ralph Kebble, Edward John Wainwright, Lewis William Davies. Graduate: Clive Graham Knobbs. MEMBER TRANSFERED TO A HIGHER GRADE From Student to Associate Member: Diethard OUo Eduard Fahrbach. I welcome the newly elected members to the Institute and congratulate the member who has been transferred to a higher grade." (Applause).

The May General Meeting of the Institute was held in Kelvin House, Johannesburg, on 21st May, 1969, at 4.30 p.m. Mr J. K. E. Douglas (Vice-President) was in the Chair. There were also present twenty-two Members, including Messrs F. P. Bath, M. Bareza, A. R. C. Fowler, D. M. Jamieson, C. M. Mavrocordatos, D. G. Maxwell and J. A. Nixon (Council Members), Messrs T. Davidson, G. L. Diering, E. T. Dunstan, D. E. H. French, K. Hodgson, O. A. E. Jackson, A. F. Lee, A. Louw, D. L. Starkey, R. K. Wheeler and M. Youngworth. Four Associate Members including Messrs D. Blair Hook and G. R. Still. One Student Mr N. A. Barcza. Thirteen Visitors, including Messrs S. H. Ash, D. L. G. Bayne, E. Bayne, S. Bell, W. S. Garrett, L. S. Gibbs, R. C. Hamilton, M. Maguire, D. Rose and J. D. van Niekerk. Total Present: Fourty-one. OBITUARY The Vice-President: "It is my sad duty to announce the death of the following member of the Institute: Thomas Spence Haldane, Member, who joined the Institute in 1924 and passed away on 21st December, 1968. As a mark of respect to the memory of the deceased and in sympathy with the bereaved, those present stood and observed silence for a few moments. MINUTES The Vice-President requested that confirmation of the minutes of the previous meeting be held over as they would only be appearing in the Journal of the following month. He also requested that confirmation of the minutes of the 75th Anniversary Meeting be held over. MEMBERSHIP The Vice-President: "I have much pleasure in announcing that the names of the under-mentioned candidates have been published in accordance with By-Law 5.2.2, and Council has elected them to membership of the Institute in the following grades: Members: Gideon Jacob Haumann, Peter John Cumming, Ian Stanley Dudman, Roderick Goldston Murchison. Associate Members: Francois Alwyn Beyers Fouche, Alan Marsh, Johannes Petrus van der Westhuysen, Waldo Edmund Stumpf, Ian Nicholas Ridley. Affiliates: Lutgerus Kolver Jooste, Roger Ainsley Ralph Kebble, Edward John Wainwright, Lewis William Davies. Graduate: Clive Graham Knobbs. MEMBER TRANSFERED TO A HIGHER GRADE From Student to Associate Member: Diethard Otto Eduard Fahrbach. I welcome the newly elected members to the Institute and congratulate the member who has been transferred to a higher grade." (Applause).

The following notes have been compiled to assist authors in the preparation of papers for presentation to the Institute and for publication in the Journal. All papers must meet the standards set by the Council of the Institute, and for this purpose all papers are referred to at least two referees appointed by Council. STANDARDS FOR ACCEPTANCE To merit consideration papers should conform to the high standards which have been established for publication over many years. Papers on research should contain matter that is new, interpretations that are novel or of new significance and conclusions that cast a fresh light on old ideas. Descriptive papers should not be a repetition of well-known practices or ideas but should incorporate developments which would be of real interest to technical men and of benefit to the mining and metallurgical Industry. In some cases a well prepared review paper can be of value, and will be considered for publication. All papers and particularly research papers, no matter how technical the subject, should be written with the average reader of the Journal in mind, to ensure wide interest. The amount of textbook material included in a contribution should be the minimum essential to the argument. The length of a paper is not the criterion of its worth and it should be as brief and concise as possible, consistent with the lucid presentation of the subject. Only in very exceptional circumstances should a paper exceed 15 pages of the Journal (15 000 words, if there are no tables or diagrams). Six to ten pages is more normal. NOTE: Papers in the Journal are printed in 10 point type, which is larger than the 8 point type used on this page. For special publications Council may decide on page sizes smaller than A4 used for this Journal. The text should be typewritten, double-spaced, on one side only on A4 size paper, leaving a left-hand margin of 4 cm, and should be submitted in duplicate to facilitate the work of the referees and editors. LAYOUT AND STYLE Orthodox sequence Title and author's name, with author's degrees, titles, position. Synopsis. Index, only if paper is long and involved Introduction, including a brief statement of conclusions. Development of the main substance. Conclusions. in more detail. Acknowledgements. References. Title: This should be as brief as possible, yet give a good idea of the subject and character of the paper. Style: Writing should conform to certain prescribed standards. The Institute is guided in its requirements by: Collins, F. H., Authors & Printers' Dictionary-Oxford University Press. Hart, H. Rules for Compositors and Readers. Humphrey Milford (familiarly known as the Oxford Rules). Fowler, H. W. & F. G. The King's English-Oxford University Press. General: A few well selected diagrams and illustrations are often more pertinent that an amorphous mass of text. Over-statement and dogmatism are jarring and have no place in technical writing. Avoid the use of the first person, be objective and do not include irrelevant or extraneous matter. Avoid unnecessary use of capitals and hyphens, while punctuation should be used sparingly and be governed by the needs of sense and diction. Sentences should be short, uninvolved and unambiguous. Paragraphs should also be short and serve to separate basic ideas into compact groups. Quotation marks should be of the 'single' type for quotations and "double" for quoted matter within quotations. Interpretations in the text should be marked off by parentheses ( ), whereas brackets [ ] are employed to enclose explanatory matter in the text. Words to be printed in italics should be underlined singly. For small capitals they are to be underlined DOUBLY and for large capitals TREBLY. If there is any problem in producing formulae accurately by typewriter they should be inserted by handwriting in ink in the copy forwarded by authors. Abbreviations and symbols are laid down in British Standard 1991. Abbreviations are the same for the singular and plural, e.g. cm for centimetre and centimetres, kg for kilogram and kilograms. Percentages are written in the text as per cent; the symbol % is restricted to tables. A full stop after an abbreviation is only used if there is likely to be confusion of meaning. Metric System: The Systeme International d'Unites (S.I.) is to be used for expressing quantities. This is a coherent system of metric units derived from six basic units (metre, kilogramme, second, ampere, kelvin, and candela), from which are derived all other units, e.g. the unit of force is the newton (N) for kilogramme metre per second per second (kg m/s2). Always use the standard metric abbreviations. Commas must not be used for separating groups of digits. For ease of reading digits should be grouped in threes counting from the decimal point towards the left and the right. Illustrations: Drawings and diagrams are to be in black India ink and should be about 18 cm wide. When submitting graphical representations avoid a fine grid if possible. Curves should be in heavy line to stand out. Lettering too should be bold as a reduction in size is often involved in the printing process. (A single column is 8.5 cm wide.) Numbering of tables should be in Roman numerals: I, 11, etc. and figures in Arabic numerals: Fig. 1, Fig. 2, etc. (Always use the abbreviation for figure.) Photographs should be black and white glossy prints. As a guide to the printer the author should indicate by means of notes in the typescript where tables and figures, etc. are to appear in the text. Paragraphs: A decimal system of numbering paragraphs may be used when the paper is long and complicated and there is a need for frequent reference to other parts of the paper. Proof correction: Galley proofs are sent to authors for the correction of printers' errors and not for the purpose of making alterations and additions which may be expensive. Should an author make alterations which are considered excessive, he may be required to pay for them. Standard symbols as laid down in British Standard 1219C should be used. SYNOPSIS It is most important that the synopsis should provide a clear outline of the contents of the paper, the results obtained and the author's conclusions. It should be written concisely and in normal rather than abbreviated English and should not exceed 250 words. While the emphasis is on brevity this should not be laboured to the extent of leaving out important matter or impairing intelligibility. Summaries simplify the task of abstractors and therefore should present a balanced and complete picture. It is preferable to use standard rather than proprietary terms. FOOTNOTES AND REFERENCES Footnotes should be used only when they are indispensable. In the typescript they should appear immediately below the line to which they refer and not at the foot of the page. References should be indicated by super-script, thus. . .1 . . .2. Do not use the word Bibliography. When authors cite publications of other societies or technical and trade journals, titles should be abbreviated in accordance with the standards adopted by this Journal. GENERAL The Council will consider the publication of technical notes taking up to three pages (maximum 3 000 words). Written contributions are invited to the discussion of all papers published in the Journal. The editors, however, are empowered by the Council to edit all contributions. Once a paper or a note has been submitted to the Institute, that document becomes the property of the Institute, which then holds the copyright when it is published. The Institute as a body is, however, not responsible for the statements made or opinions expressed in any of its publications. Reproduction from the Journal is permitted provided there is full acknowledgement of the source. These points should be borne in mind by authors who may submit their work to other organizations as well as to the Institute. P.W.J.vR.

By J. Svoboda, W. J. C. Venter, R. N. Guest

SYNOPSIS Wet high-intensity magnetic separation was examined as a method for the recovery of copper and lead from Tsumeb flotation tailings. Bench-scale and pilot-plant tests were conducted and, despite the very low magnetic susceptibilities of all the complex copper and lead minerals, copper and lead recoveries of over 60 per cent and almost 50 per cent respectively were obtained at a combined copper and lead grade of up to 13,5 per cent. The recoveries were found to be practically independent of magnetic induction in the range 0,5 to 2,2 T, and the grade of the magnetic concentrate decreased with increasing magnetic induction. The grade of the magnetic concen¬trate improved when the flowrate of the slurry was increased, and desliming was found to have a profound effect on the. metallurgical process. Particles smaller than 10 µm were not recovered, and their presence in inefficiently deslimed samples impaired the overall performance of the magnetic separation

Jan 1, 1988

By Siemag Transplan GmbH

At the Hansa Mine in Dortmund, Germany, coarse run-of-mine coal, up to 60 mm in particle size, has been brought to the surface hydraulically from a depth of 850 m since November 1977. Hoisting is done by a three-chamber pipefeeder, by means of which up to 400 t/h can be lifted. The pipefeeder operates without problems, and has so far shown itself to be efficient and reliable. Vertical hoisting can be carried out by water supplied from the surface, from underground, or from a surface water supply in combination with minewater from underground. Water that flows into the mine, which would in any event have to be pumped to the surface, can be utilized for hoisting operations. The energy costs per ton of coal for a lifting height of 850 m vary between 41 and 62 South African cents, and therefore lie within the range of costs that apply to conventional hoisting.

Jan 1, 1980

1. Book reviews Stainless Steels '84. London, Institute of Metals, 1985. £39 (U.K.), US$62 (elsewhere) Reviewer: J.B. Oalton Process engineering of size reduction: bal miling, by LG. Austin, R.R. Klimpel, andP.T. Luckie. New York, AIME, 1984. 561 pp. Reviewer: M.J. Lazer 2. Recent publications Hard and superhard materials. New York, Worltech Report Inc. (44 Woodbine Avenue, P.O. Box 212, Northport, 11768 U.S.A.), 1985. 270 pp. $1500.International comparison of standard materials-steel and cast iron, compiled by W. Oto and K. Schaning, and edited by DIN German Standards Institute e.V. Berlin, Beuth Verlag GmbH, 1985. 3rd edition, 416 pp. DM 158. Tin and its uses no. 146. Greenford (England), International Tin Research Institute, 1985. Write your own CV, by Max Kowen. Johannesburg, Legal Personnel Selections (404 Medical Centre, Cor Jeppe and Delvers Sts, Johannesburg 2001), Nov. 1985. 40 pp. R12,50 + GST.

Jan 1, 1986

By T. N. Huffman

Ancient mining and Zimbabwe T. N. HUFFMAN*. Ph.D. (Illinois) (Visitor) Ancient gold mining and Zimbabwe have been commonly associated for over a hundred years, either in terms of an exotic colony for gold export or as an African state based on the East Coast trade. The stratigraphy and radiocarbon dates from Zimbabwe and the known sequence for the Rhodesian Iron Age demonstrate that Zimbabwe was built after AD. 1000. A review of the evidence for ancient gold mining shows a similar antiquity, and a complementary rise in prosperity in Arab settlements on the East Coast indicates that gold was not extensively mined until the eleventh century. Large quantities of imported articles at Zimbabwe indicate the extent of trading during the fourteenth and fifteenth centuries, and the origins of Zimbabwe probably lay in an overflow of wealth from the gold trade during the twelfth and thirteenth centuries. Zimbabwe was abandoned by the sixteenth century because of environmental factors.

Jan 1, 1974

The 89th Annual General Meeting of The South African Institute of Mining and Metallurgy was held at Kelvin House, Johannesburg, on 20th August, 1986. Mr. H. E. James (President) was in the chair and declared the meeting open at 16hoo. Obituaries President: It is my sad duty to announce the deaths of the following members of this Institute: Life Fellow D.L. Carson; Retired Fellows T.K. Adams, G.E. Carlyon, N.M. Holford, D.E. Maclver, C.J. Morgan; Fellows S.K. de Kock, R.R. Porter, Dr G.J. Rees; and Associate Sir Lindesay Clark. As a mark of respect to the memory of the deceased and in sympathy with the bereaved, please rise and observe a moment of silence. Minutes President: The 88th Annual General Meeting of the Institute was held on Wednesday, 14th August, 1985, and the minutes were published in the September 1985 issue of the Journal. The minutes were confirmed.

Jan 1, 1986

By T. Groenewald

Potential applications of thiourea In the processing of gold by T. GROENEWALD, Ph.D. (Rand), D.I.C. (Imperial College) (Visitor) The aqueous chemistry of gold(l) that has found practical application is mainly the chemistry of the anionic complexes involving ligands such as cyanide. sulphite, and the halides. The one potential exception is the cationic gold(I)-thiourea ion. While many laboratory studies have been made during the past decade. the application of thiourea in the processing of gold is only now reaching the development stage. While thiourea is relatively inexpensive. recent interest has probably been spurred mainly by the novel technology that could arise out of the cationic properties of the gold-thiourea ion. This review outlines the chemistry of gold and thiourea. and discusses the possible use of thiourea in the processing of gold with respect to dissolution. solvent extraction. ion exchange, electrowinning. electroplating. electroless deposition. electro-etching, and electropolishing.

Jan 6, 1977

By T. Ono, B. Altansukh, S. Kawamura, K. Haga, A. Shibayama, Y. Takasaki

In recent years, the grade of silica in zinc concentrate has increased due to the degradation of zinc content and the increase in impurity content in natural ores. It implies that the development of silica removal technology from zinc concentrate is necessary to solve problems in the smelting process caused by the high content of silica in zinc concentrate. In this paper, the authors investigated the silica removal processes from silica-rich zinc concentrate by mineral processing approaches such as re-grinding and flotation. This study focused on the pulverisation process as a pretreatment for the investigation of individual minerals' liberation from the silica-rich zinc concentrates using different kinds of pulverisers. Flotation experiments were performed to separate silica and zinc concentrate from the pulverizsd feed sample using a pH regulator (NaOH), activator (CuSO4), collecting agent (PAX), and foaming agent (DOW froth 250). Results showed that the liberation rate of silica (SiO2) was reached 75% from 13% by pulverisation in an attritor with a 2 mm ball in diameter, while silica accumulated in a fraction over 20 mm in size. Flotation experiments indicated that silica removal efficiency was achieved by 44% from + 20 mm fraction obtained from pulverisation whereas the grade of silica in froth reached 1.85 mass% from 4.5 mass%. Results indicate that silica could selectively separate from silica-rich zinc concentrate, and 99.8 % zinc recovery is achieved under the studied conditions. Keywords: Zinc concentrate, silica, pulverisation, liberation, sieving, flotation

Jan 1, 2020

By M. G. Maruma, L. A. Mampuru

"Mill liner wear is a major cost item in the mining industry and there is continuous research to prolong the life of the liners. Over the years it has become apparent that even though high-chromium white cast irons are highly efficient as abrasion-resistant materials, a combination of wear resistance and fracture strength remains difficult to achieve. Increasing the hardness of the high-chrome white cast iron (HCWCI), which improves the resistance to abrasion wear, is often accompanied by a deterioration in fracture strength. Operational conditions inside the mill require that the liner should be made of highly wear-resistant material with some fracture strength. Vanadium additions ranging from 0.2 to 3 wt% were made to HCWCI in an attempt to refine the microstructure. It was found that an increase in vanadium content promotes grain refinement. A content of 1.5-3 wt% gave the best results as measured by the maximum breaking strength.IntroductionOver the years it has become apparent that even though high-chromium white cast irons are highly efficient abrasion-resistant material, a combination of excellent wear resistance and fracture strength remains difficult to achieve. The exceptional wear resistance of highchromium white cast iron (HCWCI) is attributed to hard chromium carbides embedded in an austenitic/martensitic/pearlitic matrix. When the chromium contents exceed 12 wt%, interconnected MC3-type carbides of conventional cast irons are replaced by rodshaped and isolated M7C3 carbides (Powell, 1980), leading to an improvement in the impact toughness, ductility and fatigue resistance. However, the main M7C3 carbides in HCWCI are hard and brittle and can provide an easy path for crack propagation. This limits the applications of HCWCI, particularly in severe impact conditions. Most operations involving HCWCI are in crushing and grinding and the life of a part/liner is limited by its wear resistance. However, improving the wear resistance of HWCI comes at the cost of a significant reduction in fracture strength. Concerns about premature failure of HCWCI mill liners in the mining industries prompted a study to improve the wear resistance and mechanical properties of HCWCI."

Jan 1, 2016