Search Documents

By G. P. O’Malley, A. N. Nikoloski

One of the most promising options for extraction of copper from low-grade chalcopyrite ores by heap leaching, however, chalcopyrite is refractory and suffers slow leaching kinetics and poor overall extraction due to formation of a passivation layer on the particles. The solution composition is believed to strongly affect the formation of this layer. This paper examines the effects of the major cationic species of Fe3+/2+, Mg2+, Cu2+, and Al3+ and the anionic SO42− species in acidic ferric sulfate media with a composition simulating recycle heap leach conditions. It was found that altering the sulfate, iron or aluminium concentration had significant effect on the copper extraction, the concentration of copper slightly influenced the extraction, and the amount of magnesium had no appreciable effect. Also, iron and aluminium caused a change in the sulfate concentration, and the sulfate ions had the greatest influence on the extraction of copper under recycle leach conditions

Jan 1, 2023

By C. E. Dohm

The paper serves to show the importance of both a geological model and geostatistical model that support one another in mineral resource evaluation. It highlights the advantage of reference models for the geometry, the geological, statistical and geostatistical models of various orebody types and introduces a method for quantifying the combined uncertainty in these models. The example presented reveals how the above levels of information can be applied to add value to a resource evaluation process. It is a generic example in that it is the technique of combining uncertainty in the geological model (boundaries) as well as the grade model to assess the overall risk in the estimation of the resource. Data from the coal industry is used to illustrate the techniques. The geological uncertainty is considered via categorical simulations and these are combined with simulations of the variables (grades, thickness,) being estimated in the resource. The simulation techniques used are based on the application of GSLIB software1and a general discussion of the two simulation processes is included. In conclusion the paper demonstrates how the results of two types of conditional sequential simulation can be combined to produce confidence limits that take both uncertainties into consideration. This technique does not replace the resource estimation; it serves as an additional tool to quantify confidence in the resource evaluation model. The topics considered in this contribution are in terms of continuous improvement of mineral resource evaluation.

Jan 1, 2003

Fathi Habashi, Chalcopyrite. Its chemistry and metallurgy. New York, McGraw-Hill, 1978. 165 pp. RI9,95. Loss prevention and safety promotion The Proceedings of the 2nd International Symposium on Loss Prevention and Safety Promotion in the Process Industries, Heidelberg, 6th to 9th September, 1977, are now available. Chemical reaction engineering The Proceedings of the 4th International/6th European Symposium on Chemical Reaction Engineering (4th ISCRE) held at Heidelberg, Federal Republic of Ge rmany, from 6th to 8th April, 1976, are available from DECHEMA Deutsche Gesellschaft fur Chemisches Apparatewesen, P.O.B. 970146, D-6000 Frankfurt/ Main, West Germany, at the price of DMlOO plus postage and packing. Books received The Institution of Mechanical Engineers Proceedings Volume 190. Tribos abstracts on friction lubrication wear. Published by BHRA Fluid Engineering, Cranfield, Bedford MK 43 OAJ England. Price £30 (UK), US$72 (Europe), Seawater corrosion handbook, edited by M. M. Schumaker. Noyes Data Corporation Publicity Department, Mill Road at Grand Ave., Park Ridge, NJ 07656. 494 pp. Australian mineral industry quarterly 31(1) 1978 and 31(2) 1978. Bureau of Mineral Resources, Geology and Geophysics, Box 378, Canberra City, ACT 2601 Australia. Subscriptions $8, individual number $2. Mineral and NIM reports Report no. 1996 The extraction of gold from chloride solutions. (10th Nov., 1978). Report no. 1898 Batch and pilot-plant tests on M erensky Reef ore from the Western Platinum Mine. (8th Jun., 1977; reissued 30th Jan., 1979). Report no. 1920 A mineralogical investigation of Mamatu'an and Wessels manganese ores. (15th Sep., 1977; reissued 3rd Jan., 1979). Report no. 1978 The preparation and certification of a referencesample of magnetite ore. (22nd Dec., 1978). Report no. 1998 Electrode response to the addition of zinc during the cementation of gold. (25th Jan., 1979). Report no. 2002 The spectrochemical determination of phosphorus, magnesium, and iron in phosphate rocks and sulphuric acid leach liquors. (26th January, 1979). Report no. 1992 The use of emission spectrometry for the determination of impurities in metals. (24th Jan., 1979). Report no. 2003 An electrodeless conductivity meter of improved sensitivity and reliability. (28th Feb., 1979). Report no. 2005 The spectrometric analysis of manganese-bearing materials with particular reference to ferromanganese slags and metals. (16th Mar., 1979). Report no. 2006 An examination of procedures for the analysis of dry powders by atomic-absorption spectrophotometry. (28th Feb., 1979). Report no. 2007 The instrumentation and computerization of a 25 MV.A submerged -arc furnace. (25th Mar., 1977; reissued 16th Mar., 1979). Corrosion The International Corrosion Council has decided to hold the next Internat ional Congress on Corrosion in Mainz, Federal Republic of Germany, from 6th to 11th September, 1981. Process control The First European Symposium on Real -time Datahandling and Process Control will be held in West Berlin from 23rd to 25th October, 1979. Geomechanics The 28th Geomechanics Colloquy, organized by the Oosterreichische Gesellschaft fur Geomechanik, is to be held at Salzburg on 18th and 19th October, 1979. Geosta tistics A short course on 'Geostatistics for exploration and production planning' is being conducted by the Applied Earth Sciences Department, Stanford University, California, from 27th to 31st August, 1979. Business administration The Twelfth Executive Development Programme of the Graduate School of Business Administration, University of the Witwatersrand, is to be held from 9th July to 17th August, 1979. The engineer and the law A series of four meetings on the above subject is being conducted by the Measurement, Computation and Control SubCommittee of The South African Institute of Electrical Engineers. Lead smelter for South Africa? The National Institute for Metallurgy and Gold Fields of South Africa are making a comprehensive joint investigation of the technical and economic viability of an integrated lead smelter. Conference on titanium The Fourth International Conference on Titanium will be held from 19th to 22nd May, 1980, in Kyoto, Japan.

Jan 1, 1979

2nd CONGRESS OF THE INTERNATIONAL SOCIETY FOR ROCK MECHANICS The 2nd Congress of the International Society for Rock Mechanics will be held in Belgrade, 21-26 September, 1970. The Congress will include: working sessions, study tours, receptions, excursions introduced in the working sessions and post-congress excursions and special programme for accompanying persons. Anyone interested in rock mechanics and its applicarion may take part in the 2nd Congress. Official languages of the Congress are: English, French and German. Simultaneous translation service will be provided during the Congress. All the correspondence concerning the 2nd Congress of the International Society for Rock Mechanics should be addressed to: Sekretarijat 2. kongresa Medjunarodnog drustva za mehaniku stena Institut za vodoprivredu "Jaroslav Cerni" Bulevar vojvode Misica 43, Postanski fah 530 Beograd - Jugoslavija NINTH INTERNATIONAL SYMPOSIUM TECHNIQUES FOR DECISION MAKING IN THE MINERAL INDUSTRY The Symposium which is to be held in Montreal during the week of June 14-19, 1970, follows the Computer Symposium held in Salt Lake City this year. The purpose of the Symposium is to define the role of decision making techniques within the mineral industry and to stimulate the development of specific applications. The subject of the Symposium-mathematics, operations research and computers as applied to the mineral industry-allows a complete picture of the mineral industry in its public policy, corporate, financial and technological environment to emerge. This is another of the series of symposia on this and related subjects started in the early 1960's at the University of Arizona. Sponsorship has included a number of Universities and the Society of Mining Engineers of the American Institute of Mining. This 1970 symposium is the first to be held outside of America, and is being sponsored by the Canadian Institute of Mining, McGill University and Ecole Polytechnique. A number of delegates from South Africa have participated in these symposia and several have already arranged to attend this symposium in Montreal. Enquiries should be directed to: Secretariat, The 9th International Symposium, Department of Mining Engineering, Ecole Polytechnique, P.O. Box 50l, Snowden, Montreal 248, Quebec, Canada. 24th INTERNATIONAL GEOLOGICAL CONGRESS This Congress is to be held in Montreal, Canada, from August 21 to 30, 1972. A very detailed and extensive programme has been proposed, and includes a number of excursions. Copies of the first circular are obtainable from: The Organizing Committee, 24th International Geological Congress, 601 Booth Street, Ottawa 4, Ontario, CANADA. SYMPOSIUM ON THE RECOVERY OF PYRITE The proceedings of the Symposium on the Recovery of Pyrite, held in Johannesburg on 12th to 13th June 1969 are now available. Copies may be ordered from the Secretary, S.A.I.M.M., P.O. Box 61019, Marshalltown, Transvaal at a cost of R10.00. Papers and addresses presented at the Symposium were: Opening Address by Mr J. K. E. Douglas (President). 'The world sulphur position,' by W. C. J. van Rensburg (Member). 'The South African sulphur position,' by D. L. Taylor (Member). 'The recovery of pyrite at Government Gold Mining Areas Limited,' by R. J. Westwood (Member), G. S. Stander (Affiliate) and H. R. Carlisle (Member). 'Recovery of pyrite concentrates from colliery-waste discards-A preliminary assessment,' by W. A. Gilbert (Visitor) and E. A. Nugent (Member). 'The role of pyrite in upgrading the uranium content of Witwatersrand conglomerate ores by means of the heavy-medium separation process,' by D. J. Tutt (Associate Member). 'Pyrite recovery by jigs at Durban Roodepoort Deep Limited,' by E. J. Dominy (Affiliate), F. Diamond (Affiliate) and A. D. Graham (Affiliate). 'The storage of pyrite concentrates,' by Joan C. Campkin (Visitor) and P. J. Lloyd (Member). 'The flotation plants of the Anglo- Transvaal Group,' by L. A. Bushell (Member). 'Pyrite flotation with amines and cyanidation of the products,' by E. H. D. Carman (Member). 'Gold recovery by cyanidation from mill products obtained after pyrite flotation,' by P. G. Mrkusic (Graduate), M. Sciarone (Visitor) and H. E. Simonsen (Visitor). 'The influence of sulphydral and cationic flotation reagents on cyanidation of native gold,' by K. G. Ashurst (Visitor) and W. P. Finkelstein (Member). 'Laboratory tests on the flotation of pyrite from Witwatersrand gold ores by cationic collector,' by J. Levin (Member), and M. L. Veitch (Visitor). Closing Address, by Dr R. E. Robinson (Director, National Institute for Metallurgy).

By E. J. Y., G. J. McLachlan, E. Amini, Koha

Inferring individual component flotation rates from recovery-time data of ore complexes is important in optimising and designing minerals processing plants. However, existing two-component first-order flotation models are computationally intensive to solve using conventional non-linear least squares regression. In this paper, a Convolutional Neural Network (CNN) is used to approximate the inverse function which predicts the two-component first-order model parameters using recovery-time data. This paper compares the accuracy and computation speed of the proposed CNN against traditional non-linear least squares regression on 1 million generated data based on a known two-component firstorder kinetic model. It is shown that using a CNN is possible to approximate the inverse function for the non-invertible two-component model with recovery-time as an input matrix for convolution operations. The CNN method is 450 times faster to compute than the Trust-Region (TR) non-linear least squares regression algorithm. However, the CNN model is less accurate compared to the TR algorithm overall. Keywords: Flotation kinetics, convolutional neural network, inverse problem, modelling and simulations

Jan 1, 2020

By J. P. T. Kapusta

"The copper smelting industry faces increasingly stringent environmental regulations and must continue driving innovation to reduce energy usage in its production chain. With the coming of age of ‘bottom-blowing’ copper technologies in China over the last decade, much renewed attention has been brought to tuyere bath smelting for clean copper-making. Since bottom-blowing sonic injection was originally developed and implemented in steelmaking in the 1970s and lead smelting in the 1990s, the time seems appropriate to revisit the sonic injection concepts and dispel some myths. After reviewing the trends in the copper industry and providing a brief historical context of research and development related to sonic injection, the author presents a comparison of the main submerged tuyere bath smelting technologies, namely the Noranda Reactor (NR), the Teniente Converter (TC), and the Chinese Bottom-Blowing Smelting Furnace (SKS/BBS) for copper, and the Queneau-Schuhmann-Lurgi Reactor (QSL) for lead. The core of this article, however, consists of a brief description of the fundamental theories for sonic injection (jetting regime) and ‘sonic flow mapping’ to illustrate the relationship between the minimum tuyere back-pressure required to achieve sonic flow and the tuyere internal diameter. The article also offers a comparison between side- and bottom-blowing in jetting regime before concluding with the author’s vision of the new trend in submerged tuyere bath smelting. IntroductionIn the last decade, developments in the copper smelting industry have been driven by two key concepts: (1) increasing cleaner smelting capacity to meet the world’s growing copper demand, as illustrated in Figure 1, and (2) increasing process off-gas capture to comply with more stringent environmental regulations and abide by a corporate social responsibility ethic of a clean work environment (for smelter employees) and clean air (for families living around smelters). The copper smelting industry has also faced some major challenges in the last few decades, including (1) low treatment and refining charges (TC/RC or processing fees) impacting custom smelters, (2) lower concentrate quality and grades with higher levels of impurities (e.g. As and Hg), (3) higher processing and transportation costs due to the rising cost of energy, (4) restrictions in process intensification (tonnage oxygen usage) due to furnace integrity limits, and (5) scarcity of educated and trained personnel due to fewer metallurgists graduating from pyrometallurgical school programmes combined with a high retirement rate of skilled workers."

Nov 1, 2018

By M. Weir, J. R. Cutland, L A. J. Pronk van Hoogeveen

"A computer system for the design of open pits to mine stratiform orebodies has been developed for use at Nchanga Consolidated Copper Mines, Ltd. The particular requirements of such a system, for example, the accuracy of representation of geological detail and the ability to follow footwalls, arc described in this paper, together with the methods that have been adopted to satisfy them.A modified version of the Open Pit Design Program of Rio Tinto Zinc Consultants, Ltd. is incorporated in the system and the geological data are converted into a form usable by the computer by means of a pencil follower. Some of the uses which have been made of the system are described, with reference to the long- and medium-term planning of the Nchanga Open Pit, the major producing pit at Chingola Division."

Jan 1, 2014

By I. H. Clark

A variety of backfills is presently being placed in different gold mines. The backfills are pumped as slurries to stopes where they are discharged into some form of retaining paddock. The effectiveness of fill as a support medium will depend on a number of factors. These can largely include (i) inherent properties of the material, e.g. particle size, shape, distribution and com- position, and (ii) conditions of placement. The terminology required for describing backfills is introduced, and the various laboratory-measured properties are presented for a variety of fills. Finally, the properties of the fills as they are placed underground are discussed.

Jan 1, 1988

By A. Drumond, J. F. C. L. Costa, M. G. Lemos, A. L. Rodrigues, F. G. Niquini

The past decade has seen a renewed possibility of using machine learning algorithms to solve a large collection of problems in several fields. Data acquisition for mining operations has increased with the growth in sensor-based technologies, and therefore the amount of information available for mining applications has dramatically increased. Ore sorting equipment is available for separating ore from waste based on differences in physical properties detected by a real-time analyser. The separation efficiency depends on the contrast in these properties. In this study we investigate the application of machine learning models trained using data from the output of a dual-energy X-ray ore sorting apparatus at a gold mine. The particles were first hand-sorted into ore and gangue classes based on their mineralogical composition. Classification models were then used to help decide the balance between the number of true and false positives for ore in the concentrate, with a view to economic parameters, using their receiver operator characteristic (ROC) curves. The results showed AUC (area under the ROC curve) scores of up to 0.85 for the classification models and a maximum reward condition Fpr/Tpr around 0.5/0.9 for a simplified economic model.

Aug 8, 2024

By H. Manurung, I. M. Bendiayasa, W. Astuti, and H. T. B. M. Petrus, F Anggara, K. C. Wanta

The leaching kinetics of cerium (Ce) and yttrium (Y) in sodium-hydroxide-digested non-magnetic coal fly ash using acetic acid were investigated. The variables analysed were pH, solid-to-liquid ratio (S/L), and temperature. The results show that cerium and yttrium's maximum recovery was 57.33% and 58.36%, respectively, under leaching temperature of 90°C for Ce and 60°C for Y at pH of 1,74 and 10 g/mL solid-liquid ratio in 240 minutes. Increasing the leaching time to more than 120 minutes did not significantly improve the results. After the magnetic separation process, the ICP-OES analysis shows a slight increase in the concentration of cerium and yttrium on nonmagnetic components. The XRD and ICP-OES analysis for the sample before and after silicate digestion shows that 40% silicate was dissolved. The calculation of apparent activation energies of leaching using the Arrhenius law for the leaching of cerium and yttrium gives 22.72 kJ/mol and 35.84 kJ/mol, respectively. The kinetic leaching model of cerium and yttrium all fit Dickinson's new shrinking core model. The calculation results show that the leaching reaction is controlled by combining interface transfer and diffusion across the product layer.

Nov 6, 2024

By A. R. Javadi

Pyrite (FeS2), chalcopyrite (CuFeS2), sphalerite (ZnS) and galena (PbS) generate hydrogen peroxide (H2O2) when placed in water, with pyrite generating the most amount of H2O2. The order of these minerals for generating H2O2 in water is: pyrite > chalcopyrite > sphalerite > galena. In previous research, the methods of generation of H2O2 in the grinding mill were studied. In this study, data from experiments were included by using MODDE 9 software for six parameters composed of water, grinding media, particle size; adding collector to the grinding, and adding depressant and pH. Finally the optimal condition was achieved. According to the results, most of the recovery is related to the particle 75 μ size and when using processed water, adding 100% collector and without depressant and pH 10. The most recovery of lead in the case of the use of fresh water is in the case of 100% collector, without depressant, pH 10 and 150 μ particle size. Maximum recovery in fraction size 45 μ in the case of water process is 100% collector, without depressant and pH 10. Maximum depressant of pyrite will be the fraction size 75 μ, distilled water, without collector, 100 depressant. Keywords: Sulfide mineral, hydrogen peroxide, flotation, oxidation

Jan 1, 2020

The October General Meeting of the Institute was held in Kelvin House, Johannesburg, on Wednesday, 21st October, 1970, at 4.30 p.m. V. C. Robinson (President) was in the chair. There were also present 25 Fellows, including J. K. E. Douglas, Prof D. D. Howat, D. G. Maxwell, Dr R. E. Robinson, P. A. von Wielligh (Council Members). D. Ayres, G. Burrow, E. H. D. Carman, D. L. Carson, M. E. E. Douglas, S. A. Finney, W. R. Flook, A. J. Freemantle, W. A. Gilbert, E. B. Gordon, B. W. Gray, J. M. Jacobs, P. H. Kitto, C. H. Kruger, Dr P. J. D. Lloyd, D. G. Malan, W. Pilkington, W. G. Pyne-Mercier, K. S. Rae, W. T. Ruhmer, D. J. Tutt and D. T. Watt. Seven Members, including E. J. Dominy, S. I. du Preez, L. V. Grobler, D. R. Lings, G. D. Louw, J. S. A. Oelofse and O. B. Prentis. Fifteen Visitors, including J. R. Coppin, Dr A. Faure, P. E. Franzl, G. P. Hart, D. van Heerden, A. W. Hunt, A. R. F. MacDonald, B. G. Meyburgh, P. H. Radcliffe, J. M. Shirley, T. H. Tunley, A. D. Vellema and R. E. Wheeler. Secretary, D. C. Visser. Total present: 49. OBITUARIES The President: "It is my sad duty to announce the death of the following: Sir George Arthur Davenport, Honorary Life Fellow, who joined the Institute in 1930 and passed away on 17th September, 1970. The late Sir George was also, for many years, our corresponding member for Rhodesia. Andrew Malcolm Carmichael, Associate, who joined the Institute in 1944 and passed away on 22nd August, 1970. Cyril John Douglas Veal, Life Fellow, who joined the Institute in 1929 and passed away on 27th August, 1970. As a mark of respect to the memory of the deceased and in sympathy with the bereaved I would ask you all to rise and observe a few moments' silence." CONFIRMATION OF MINUTES The President: "May we confirm the minutes of the Annual General Meeting held on 26th August, 1970, and the minutes of the monthly general meetings which were held on the 20th of May and the 17th of June, 1970, as published in the August 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: Members: Nikolaos Lalakakis, Gordon Phillips Rundle. Associates: Henry du Preez, James Robert Forbes, Johannes Stephanus Albertus Oelofse, Casper Vorster van Heerden. Graduates: Michael Harold Crosbie, Graham Robert Wallis Walker, Gary Walker Braithwaite. Students: Mohammad Ali Kazemzadeh, Gerhardus Petrus Benade. APPLICATIONS FOR TRANSFER From Graduate to Member: James Wormald. From Student to Graduate: Peter John Cook, Pieter Willem Greeff. "I welcome the newly elected members to the Institute and congratulate the members who have been transferred to a higher grade." PAPER FOR PRESENTATION The President: "This paper is entitled 'The Design, Erection and Operation of a Purlex Plant at Buffelsfontein Gold Mining Company Limited'. It is presented to the Institute by Mr B. G. Meyburgh, a visitor to our Institute. He is a graduate of the University of the Orange Free State and is the Uranium Plant Superintendent at Buffelsfontein and he, therefore, is in a very strong position to describe this very excellent job which is being done as he has been associated with this plant from the inception." After the presentation of the paper the President said: "Gentlemen, the paper you've heard from Mr Meyburgh is a very concise and interesting account of an important piece of work, and I think the title is so completely descriptive of the subject, which is admirably set out in the paper which you have heard. You probably haven't all had the opportunity of reading it, but you very soon will. I found it interesting to note that the results predicted were surpassed in the operation of the plant to date. The actual results obtained are significantly good, I think. Any process which, in this country, increases production and decreases costs, is to be welcomed, particularly when it is so necessary for South Africa almost to bend over backwards to utilise every avenue available in order to increase the scope of the production for overseas' markets, of her metallurgical and mineral potential. In lighter vein-and there is no reason why we should always be so serious-I am glad to see that, in a scientific journal like this, such words as the American word 'crud' which I have been picked out about so often, because my grandchildren use it, is now given an aura of respectability. Thank you very much, Mr Meyburgh, for an interesting paper. We have a long list of contributors, and I am not going to waste any more time. I am going to call on Mr Tunley of the N.I.M. for the first contribution." T. H. Tunley, P. de Bruyn (read by A. D. Vellema), E. J. Dominy, E. H. D. Carman, A. R. F. MacDonald D. C. Streicher (read by P. H. Radcliff), Dr A. Faure and Dr P. J. D. Lloyd then contributed to the discussion. (This discussion will appear in a later issue of the Journal.) The President: "I wish to thank members and visitors for their attendance, and now declare the meeting closed." The meeting closed at 6.05 p.m.

By B. Maybee, J. Venter, J. Wesseloo

The selection of open-pit slope angles involves high-value decisions with small changes in slope angle, often representing significant changes in net present value. The existing methods used to define design acceptance criteria have evolved from factor of safety to probability of failure (P[F]) to risk consequence to risk frontiers, which represents current state of the art. Current design acceptance measures are based on references to published tables representing the experience and judgement of their authors, who did not specify the purpose of the measures contained therein. As the purpose of the published design acceptance criteria is not specified (i.e., definite stability, marginal stability, optimization, etc.), such tables cannot be used to achieve optimum slope angles that maximize profitability. This paper develops a design acceptance criterion that maximizes profitability by defining a formulation for optimum risk that balances expected risk and reward. The model developed is titled the Mining Risk Model (MRM), and is applied to open-pit slope angle selection through an equation for optimum probability of downside (P[D]O) that balances the upside or opportunity, the P[F], and the downside impact. This formulation for optimum risk is unique, as many authors have presented objective functions for their risk models that can be optimized, but none of the sources reviewed contained a formulation for optimum risk. The MRM is sufficiently flexible to allow the design performance measure that drives P[F], and hence P[D]O, to be selected based on the intended goal. Furthermore, the essential information that must be known to quantify optimum risk is defined. This allows users to determine what information to collect for optimum risk decisions. A further benefit of the MRM is that slope angle decisions and pit shells can be ranked to select the best option, and a threshold is provided that separates acceptable from unacceptable decisions. Finally, the workflow and information required to determine optimum risk are presented.

Sep 9, 2024

The Annual General Meeting of the Institute was held in Kelvin House, Johannesburg, on Wednesday, 30th August, 1972. Professor D. D. Howat (President) was in the chair. There were also present sixty-two Fellows, twenty-four Members, two Associates, three Students and eighteen Visitors, making a total of one hundred and nine. The President declared the meeting open at 4.05 p.m. OBITUARIES The President: It is my sad duty to announce the death of six members of this Institute. The first of these is Dr A. J. Orenstein, Honorary Life Fellow, who joined the Institute in 1916 and died on Seventh July. Dr Orenstein became almost a legendary figure in Medicine as a result of his work in the control and elimination of malaria during the digging of the Panama Canal and I believe he was actually engaged working until four days before his death. The other members who have died are: F. Meyer, died on 8th June; S. D. Loxton, Fellow, died on 13th May; J. Innes, Fellow, died on l0th January, 1970; O. B. Prentis, a Member, died on 4th June, and J. Brits, Associate, died on 27th June. As a mark of respect to the memory of the deceased and in sympathy with the bereaved may I ask you to rise and observe a few moments silence. MINUTES The President: 'The second item on the Agenda, the minutes of the meetings held on March 22nd and May 10th, 1972, as tabled. May I confirm these minutes'? Agreed. WELCOME TO VISITORS 'On behalf of the Council, may I say how delighted we are to have such a splendid gathering with us on this our Annual General Meeting. Dames en here vir die omvang van my Afrikaanse woordeskat verdien ek weinig lof, boonop is dit nog Afrikaans met 'n Skotse aksent, wat u asseblief moet verskoon. Tog wil ek se hoe dankbaar ons is dat sy Edele, die Minister van Mynwese, dr Koornhof en mev Koornhof vandag hier teenwoordig kan wees. In addition to our own newly appointed Minister of Mines, we are also honoured by the presence of the Minister of Mines of Rhodesia, Mr I. B. Dillon. I think not even our oldest members can recall an occasion on which two Ministers of Mines were present at a meeting of the Institute. It is a particular pleasure to welcome them this afternoon. I am happy to say that Minister Koornhof is an Honorary-Vice President of the Institute, and Minister Dillon is an Honorary Member. The presence of your goodselves, gentlemen, with us this afternoon, I am sure underlines the great significance which we believe both countries attach to the economic exploitation of the vast mineral resources of Southern Africa. For over 70 years, this Institute and its members have been making their contribution to this great task of mineral exploitation, and we feel that your presence with us today, is a token of the confidence of your governments in what this Institute and its members have been endeavouring to do. Also present with us today, is Mr R. C. J. Goode, President of the Chamber of Mines, and Honorary President of this Institute. I was going to say I welcome Mr Goode, but it is rather difficult to welcome a man to his own home, and this is the case with Mr Goode. He is a very distinguished and a very recent past president of this Institute and he remains now, as he has been for as long as I can remember, one of our most active and valuable members. This I think, ladies and gentlemen, is the second rather unique feature of this occasion this afternoon, because no one else can recollect an occasion on which the President of the Chamber of Mines was also a past president and an active member of our Institute. A special word of welcome, Mr Goode. Mr Tommy Gibbs, our Government Mining Engineer, is in a somewhat similar position as he is also a member and an old and valued friend of our Institute, - welcome to you, Mr Gibbs. Mention I think, must be made of the fact that we are very glad to have with us Dr A. J. A. Roux, President of the Atomic Energy Board, and Mr Stanley Craib, President of the Associated Scientific and Technical Societies. Then, within the great family of the A.S. and T.S., we have the presidents, or the vice-presidents of I believe 13 of the constituent societies. These gentlemen, like all the rest of us, have the rather tiring task of supporting and upholding their fellow presidents on occasions such as this. We particularly appreciate their presence this afternoon and the effort they have made to be with us. We are happy to have with us: Dr R. E. Robinson, Director-General, National Institute of Metallurgy, Mr E. Boden, Manager, Associated Scientific and Technical Societies, Dr H. G. Denkhaus, President, The S.A. Institute of Mechanical Engineers, Mr G. Goedhals, Vice-President, S.A. Institute of Electrical Engineers, Mr E. Dalton, President" S.A. Institute of Certificated

By J. O. Claassen

"Homogeneous populations are required to perform descriptive, probabilistic, and inference statistics and to support stable, predictable mining operations. The geological and downstream processing environments are, however, highly heterogeneous. The complex nature of mining environments requires means to identify and define multipopulation environments that could affect the performance of mining value chains. A study performed at several operating mines suggests that the impact of heterogeneous or variable geological, mining, and plant processing environments on overall mining value chain performance may not be a key focus area at these operations. This was illustrated through the use of basic and spatial statistics, which included the log-probability plot, a modified range equation, and chronovariography. The findings reflect high relative variability in the geological and processing environments studied and mining operators’ inability to effectively deal with the sources and consequences of variability. The study suggests that a focus on heterogeneity in complex mining operations may significantly enhance overall mining performance. IntroductionHeterogeneity and why it mattersHeterogeneity refers to a state or quality of being variable/diverse and comprising different non-compatible elements or parts. In statistical terms a heterogeneous population can refer to a population comprising different non-compatible sub-populations or a multipopulation environment. The latter is commonly found in natural environments such as geological environments (Bardossy and Fodor, 2001). The inherent heterogeneity of complex geological environments is also referred to as spatial heterogeneity. Heterogeneity or variability, however, also occurs over time at mining operations. A case in point is variable ore composition on a conveyance system feeding a processing plant or product stockpile.Heterogeneity associated with the mining environment can significantly influence key aspects of day-to-day mining operations such as sampling, the use of descriptive, probabilistic, and inference calculations, and an operation’s ability to manage and control the mining value chain as a whole."

Jan 1, 2016

By Y. Yang, L. Li, X. Liu

Coal mining in China is facing the transition from output to quality. Based on the total mining capacity and average production, the current situation of coal mining at mine, city, and province levels is analysed, and data in support for the layout of sustainable mining development and the optimization of output provided. The results show that 87% of China's coal is mined by underground methods, with an average production capacity of 0.93 Mt/a per mine. Open pit mining accounts for 13%, with an average mine production capacity of 5.73 Mt/a. The average mining capacity of coal mines in China is 1.05 Mt/a, with 1181 coal mines with an average capacity less than 0.3 Mt/a, accounting for 35% of the total coal mines but contributing only 4.51% to output. They are distributed in about 48 cities in six provinces, seriously restricting the transition to green coal mining. The coal industry should speed up the closure of small coal mines in key provinces and cities, eliminate outdated production capacity in the central region, increase the speed and proportion of coal resources moving westward, and promote high-quality development of coal mining.

Jan 26, 2023

"Chairman: Professor C. O. Frush Rapporteur: Mr A. C. SchmidtPapers:Planning of underground copper mining by J. K. Williams, L. Smith and M. P. WellsLinear programming models of copper leach and solvent extraction plants by W. P. C. Duyvesteyn, J. R. Cutland and J. R. L. RusselPlanning and forecasting stope production by D. W. Kappes and P. F. X. Moussett-JonesA proposed method of dynamic ore reserve assessment for a caving system of mining by A. F. Spinks and S. P. NicholsThe initial point made by Mr L. Smith in presenting his paper was that the planning aid outlined in the preprint was neither sophisticated nor complicated. However, it was a system which worked and was a very real way in which the computer was being used to assist miners, in particular, who at the present moment have very little experience in the use of computers.Mr Smith apologised for the fact that the editors of the paper had eliminated all reference to 'time'. This was very unfortunate because the essence of the system was that it saved time, which was one of the main points made in the paper.The operations being planned by this means cover the Rokana orebody which is a stratiform body mined by open stoping.The planner has to decide how much ore to mine from each base in each time period of his plan, that is, from three to four months hence to a year ahead. Normal procedure is for the planner to have discussions with the underground manager on some of the information he requires. The sort of information needed is (i) tramming limits for each face, (ii) extraction and grade factors, (iii) the present status of mining operations so that the planner knows where to start the new plan, and, (iv) details of any other mining consider¬ations that need to be incorporated in the plan.The objective at this point is to produce an initial plan for discussion purposes. All the information required comes from one sheet per stops and shows, inter alia, the stope identifier, the length along strike, the ore tonnage, the copper and cobalt grades and, finally, the extraction and grade factors.The program itself, among many other things, checks the data for validity, compatibility, completeness and credibility and prints error messages accordingly. Output from this system is in the form of a summary of production from each face, as well as giving the figures of ore reserve depletion. This summary indicates which slopes are to be mined in this time period, the original survey grades (copper and cobalt), the estimated production grades, how much is to be mined from each stope and the copper and cobalt production accordingly."

Jan 1, 2014

By D. H. Diering

Definition of mineral resources and reserves forms the basis for effective mine planning and reliable public reporting of mineral assets. Historically the mineral resource and reserves declaration process has been the domain of the geology and surveying disciplines, with the declaration of the reserves by the surveyor being based on the application of modifying factors to the declared resources available for mining. As part of an ongoing process to improve efficiency, reliability, and reproducibility of results, this approach has been revised and enhanced through the introduction of a revised process and reconciliation tools. The revised approach to reserve definition is based on the definition of scheduled resources, at an appropriate confidence estimate in the context of an approved business plan, over the anticipated life of the mineral asset being applied to define reserves. This planning and scheduling is developed, during the annual business planning process, by the mine planning department using tools such as CADSMine?. The scheduled area together with the application of revised modifying factors is tabulated in the BME (basic mine equation) and reflects the mine production plan over time. Simplification of the modifying factors to dilution and losses underpins the simple yet robust approach to improved definition of reserves in this process and in the basic resource to reserve equation (BR2RE). Dilution intrinsically affects grade but not metal content, whereas the losses reflect both the efficiency of mining and planning and are reflected in metal losses, area losses, or both. Reconciliation of the derived ?resource converted to reserve? area, (which is based on the business plan from CADSMine?), versus the ?resource available for mining?, (which is derived from Datamine?), underpins the robustness and auditability of the reserves declaration. This R&R accounting and reconciliation approach is transparent and facilitates interrogation of the logic and rationale of long-term business planning and project strategy. These numbers are processed and reported in the logic of the basic resource equation (BRE), which also addresses aspects such as white areas (future and historic), tail management, and partial extraction (non-scheduled pillars, etc.) in compliance with SAMREC definitions. Areas that do not have the necessary confidence and data support to be declared as resources find their space as pre-resource (outside the domain of public reporting), outlining existing potential for future extraction and reporting. Use of the BRE leads ultimately to a complete, refined accounting and reconciliation-oriented approach for all production entities. The revised resource and reserve process includes the discipline of mine planning as intrinsic to the definition and declaration of resources and reserves. Subsequent to the change in process, the resources and reserves have truly become the domain of the mineral resource management discipline. This paper defines the logic of the basic resource equations and outlines their application in the definition and reconciliation of mineral resources and reserves at Anglo American Platinum Limited.

Jan 1, 2012

By S. C. Maji, U. S. Chattopadyay, S. Chaudhuri, T. Gouri Charan

India is devoid of coking coal resources, which is a vital raw material for coke making. As a result it has to import about 80% coking coal for steel making. Indian National Steel Policy, 2017 has envisaged crude steel production around 300 million tonnes Mt) by the year 2030-31 and forecasts coking coal demand of 161 Mtpa (million tonnes per annum). One way of improving the indigenous resources is to study the performance of existing washeries and to improve the clean coal recovery by adopting suitable technology. A study was carried out, mainly to focus on the fine coal circuit of an existing coking coal washery, to generate the desired quality of clean coal. The operating coking coal washery being studied is presently feeding coal from nine different sources with varying feed ash contents. The coal fines varied in ash content ranging from 19.5% - 43.6%. For treating the coal fines, the washery has operated a spiral for the past few years. Performance studies were carried out, and it was found that the spiral is not efficient in recovering the cleans. Detailed investigations were carried out on the coal fines using flotation techniques, and it was found that to achieve a low ash clean coal, the froth flotation is a much better beneficiation option than a spiral, The studies showed that the recovery of clean coal through a spiral is 67.7% at ash content of 27.0%, while flotation tests showed a recovery of 68.1% at 16.5% ash content. Keywords: Coking coal washery, near gravity material, spiral washer, froth flotation

Jan 1, 2020

By G. Akdogan, S. M. Bradshaw, M. I. Isaacs, P. Van Wyk

In the mineral processing industry, Ni-Cu-Fe-S converter matte is leached in order to remove base metals from a concentrate containing platinum group metals (PGMs). This paper investigates the atmospheric leaching process, in order to develop a better understanding of the leaching behaviour of the base metals; in particular Cu, Fe, Ni, and the PGMs in particular Ru and Ir with key process variables, acid concentration, copper concentration under oxidative leaching conditions. Higher initial acid concentration resulted in a higher copper, iron and nickel extractions, as well as higher leaching rates together with faster Cu, Ru, Ir precipitation occurring. On the other hand, a higher initial copper concentration resulted in more nickel but less iron being extracted. Keywords: PGM, converter matte, leaching, precipitation

Jan 1, 2020