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By K. Wu, L. Li, D. W. Zhou, J. W. Yu

The presence of a fractured water-conducting zone (FWCZ) is of significant importance for the safety of underground mining under water bodies. When a coal mining area is covered with a thick layer of alluvial soil, the height, width, and distribution pattern of the FWCZ in the area shows unique features. The internal mechanism by which thick alluvial soil affects the FWCZ is still unknown. Using the Huainan coal mining area (HCMA) in China as a case study, we investigated the impact of thick alluvial soil on the height, width, and distribution pattern of the FWCZ through numerical simulation using the distinct element method, theoretical derivation, and data validation. The results indicate that a thick layer of alluvial soil inhibits the FWCZ height and increases the FWCZ lateral width. When the soil-to-rock ratio is greater than a certain value (the numerical result in this study is 15:18), the FWCZ height and width are affected by the thick alluvium significantly, and the thick alluvial soil alters the shape of the FWCZ from tall and thin to short and wide. The load exerted by the alluvial soil transfers downward to influence the FWCZ; however, this process is obstructed by the hard strata in the bedrock. Therefore, the vertical and lateral change trends show a similar step pattern. Our results can provide a basis for accurate calculation of the FWCZ height in mining areas with thick alluvial soil, to mitigate mine water hazards and increase the safety of underground mining in coal mines covered with a thick alluvium layer. Moreover, reducing the FWCZ height can help extend the upper extraction limit in coal mines covered with a thick alluvium layer, which reduces the thickness of the impermeable coal pillar and increases coal production.

Jan 1, 2016

By J. O. Claassen

"SynopsisMining value chains are dynamic systems and should be managed according to systemic flow-based principles. This includes a detailed focus on the impact of variable geological conditions on material flow, product quality, and production cost, visibility of the total mining system to operators and managers, as well as the synchronization of resources and activities in downstream processes. Thirty mining operations across the African continent were studied to establish to what extent systemic flowbased principles are applied in day-to-day operations. The study indicated that although most mining operations have identified the relevant geoprocessing variables, only a small number apply this information in a flow-based management approach. Most mining operators do not focus on developing a clear flow view of the mining value chain and on making it visible to operators and managers to enable them to optimally set and reset operations. Daily synchronization of geoprocessing variables is limited to a small number of variables, e.g. synchronizing ore hardness with drilling or milling requirements, in less than 30% of the operations evaluated. Operations where these principles have been adopted reported a noteworthy improvement in performance. The study indicates that notable potential exists in most of the operations evaluated to implement flowbased management principles, including geometallurgical principles. This can significantly improve value chain performance without exorbitant capital layouts and enhance ROCE. IntroductionObjective of the studyThe study seeks to establish to what extent systemic flow-based principles have been adopted in the southern African mining industry and the implications thereof. Specific attention is given to the importance of defining and managing geoprocessing dependencies (geological variables directly impacting mining and plant performance – the geometallurgical approach), establishing a flow view of the mining system, which typically includes a dashboard of the flow of ore/product quality and cost from the mining face to the customer, and limiting the impact of dependencies through synchronization of activities and resources, e.g. ensuring that a continuous miner does not wait for a roofbolter, or that reagent addition rates are matched with a specific ore/concentrate composition."

Jan 1, 2015

By M. S. Shishvan, J. Sattarvand, R. S. H. Meij

Navigating miners during an evacuation using a smart evacuation technology can significantly decrease the evacuation time of an underground mine in case of an emergency. This paper presents a mathematical programming model to calculate the most efficient escape path for each miner as a critical component of the smart evacuation technology. In this model, the total evacuation distance of the crew is minimised and scenarios with blocked pathways, and stamina categories for the miners are simulated. It was found that all the tested scenarios are technically feasible. Using the feature that filters out blocked pathways has no downsides, as safer routes are calculated, and there is no penalty in the computation time. The paper also discusses the social and technical issues that need to be overcome before the algorithm can be implemented as an actual escape solution.

Sep 1, 2021

By T. M. Evers, R. P. Van Den Berg

Ancient mining in Southern Africa, with reference to a copper mine in the Harmony Block, north-eastern Transvaal T. M. EVERS. B.A. (Birm.) (Visitor) and R. P. VAN DEN BERG. B.Sc. (Wits.) (Visitor) A recently discovered mine on the farms Harmony 24 and 25 in the Letaba district has been investigated archaeologically by T. M. Evers and geologically by R. P. van den Berg. The archaeological investigations shed light on the mining techniques and accompanying metallurgical techniques, while the geological investigations give information on the structure and mineralization of the mine. Comparisons with other investigated ancient workings show that mining was well understood in Iron Age times, before the African peoples had any contact with Europeans.

Jan 1, 1974

By K. A. du Preez, P. J. van Staden, M. van Rooyen

Mine-impacted water, including acid mine drainage (AMD), is a global problem. While precipitation of dissolved metals and neutralization of acidity from mine-impacted water is accomplished relatively easily with lime addition, removal of sulphate to permissible discharge limits is challenging. This paper presents a high-level comparison of four sulphate removal technologies, namely reverse osmosis, ettringite precipitation, barium carbonate addition, and biological sulphate reduction. Primarily operating costs, based on reagent and utility consumptions, are compared. Each process is shown to be subject to a unique set of constraints which might favour one over another for a specific combination of location and AMD composition. Access to and cost of reagents would be a key cost component to any of the processes studied. The total cost calculated for each process also depends on the type of effluents that are allowed to be discharged.

Oct 1, 2021

By B. P. Watson, D. Hoffmann, D. P. Roberts

Potholes on the Merensky and UG2 reefs in the Bushveld Complex occur as near-circular to elliptical depressions or slumps on the reef horizon, normally presenting as severe disruptions which prevent economic extraction. Within the pothole, the reef and other strata may either be attenuated, absent, or highly deformed, this being the result of the overlying hangingwall strata having slumped down. The hypotheses for pothole formation involve several mechanisms, including downward erosion, upward fluid movement, or synmagmatic deformation. When potholes are exposed in mine workings, significant fracturing is often observed. This fracturing is particularly evident in anorthosite rock types. Stress measurements were conducted in a pothole on the Merensky Reef to determine if the fracturing was due to high stress conditions. The paper describes the measurement results and numerical modelling that was done to determine the influence of depth and mining on the stress condition at the site. The results show that high stresses do exist in at least some potholes, and that current formation theories do not adequately explain the measured stresses. In support of understanding the high local stress associated with the pothole, the study explored several rock engineering modelling processes to validate the conditions of the study site and enclosing excavations. A better understanding of the stress conditions in potholes with additional data could lead to more appropriate support design and avoidance of potential rockbursts in these structures.

Jan 1, 2021

By A. Modi, C. Li, R. Kabwit, W. Y. Xinchao, R. Joshi

The KIMIN copper project can treat 1.7 million dry t/a copper-cobalt ore. It has three mills in operation, two using conventional milling in water and the third in raffinate. We introduce the project process circuit and the capital and operating costs of using the raffinate process compared with conventional milling in water. There is a capital saving of approximately 11.5% for major equipment by removing the pre-leach thickener. In addition, it also achieves an annual operating cost saving of USD 2.1 million due to an increase in 49% of acidic raffinate recycled and reduction in lime consumption. The features of CITIC’s new duplex stainless-steel ball mill ,as the key equipment of the system, are also introduced

Jan 1, 2023

By C. Gatschlhofer, A. Krammer, H. Raupenstrauch, T. Hochsteiner, A. Holzer, L. Wiszniewski

The rising demand for lithium-ion batteries, coupled with international climate targets, emphasises the need for circular economy and zero-waste recycling approaches. However, so far, no industrial-scaled solutions are available that fulfil global recovery targets. Therefore, a novel pyrometallurgical reactor was developed at the Chair of Thermal Processing Technology at Montanuniversitaet Leoben to avoid lithium slagging and recover volatile elements via the gas phase. Nevertheless, previous results show that several impact factors, including interfering elements or pre-treatment steps, strongly limit the recycling efficiency of black mass. To simulate the black mass and provide feedback on possible influences of pre-treatment steps, cathode material from production with additives of interfering elements was analysed regarding melting behaviour. The results show that formation of a further processable alloy was increased by almost 50% when pretreatment steps were excluded, indicating pre-treatment steps as a major influence to be considered within this specific recycling route.

Jan 1, 2023

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

By Z. Botha

Sheryl Sandberg, the COO of Facebook, published a book titled 'Lean In', where she invites women to sit at the table. In summary, to 'sit at the table' entails not only embracing opportunity, but to actively seek out opportunities in leadership positions. Sandberg points out that, unfortunately, apart from institutional obstacles, a woman's own perceived limitations have a negative impact on her leadership ambitions. To create an environment where diversity will flourish, where everyone has a seat at the table and everyone has a voice, safety must be established first. To establish safety within a diverse team, there is power in relationships and connections. This study will first and foremost review theories in literature as to why diversity and inclusion are so important and the value that diversity brings to our industry. The study also recommends a few focus areas for improving diversity and inclusion in the industry.

Sep 1, 2022

By L. Naude, J. Cloete, S. Engelbrecht

The results of an investigation evaluating whether an industrial plant, currently operating using sodium isobutyl xanthate (SIBX) as primary collector for sulphide minerals (mainly chalocopyrite), could adapt to operate using an alternate primary thiol collector without compromising plant and metallurgical performance. Initial laboratory scale flotation tests identified commercial dithiophosphate (DTP)-based and thionocarbamate (TC)-based collectors, that when blended, showed potential to replace the incumbent SIBX primary PGM collector. Industrial plant trail results show that there was no deterioration in recovery of 4E PGMs, even at a lower concentrate grade when operating the plant on the identified (DTP + TC)-based collector blend compared to SIBX. The effect on Cr2O3 content in the final concentrate was also found to be negligible. The (DTP + DTC)-based collector blend also showed promise in terms of plant adaptability in accommodating a new primary specialty collector blend. These observations highlighted the potential of replacing xanthate primary collectors with alternate thiol collector blends for PGM flotation. Keywords: PGM, xanthate replacement, specialty collector, sodium iso-butyl xanthate (SIBX), dithiophosphates (DTP), dithiocarbamates (DTC)

Jan 1, 2020

By M. J. Southwood

SYNOPSIS Experiments carried out under atmospheric pressure and temperature (25°C) and sterile conditions show that the dissolution rate of nickel and copper from a pyrrhotite-pentlandite-chalcopyrite ore in a lixiviant of sulphuric acid is greatly enhanced in the presence of pyrite. At a pH value of 1,8 and in the presence of pyrite of equal mass to that of the ore, the recoveries of nickel and copper improved dramatically (21 and 80 per cent respectively). At a pH value of 4,0 the recovery of nickel was enhanced, but the chalcopyrite was refractory. A galvanic mechanism is probable, but cannot be proved from these experiments. The economic implications of the results are discussed.

Jan 1, 1985

By S. Chai

Waste dumps are widely used to discharge stripped mine wastes in open pit mining methods. As mining progresses, the height of the waste dumps will increase gradually, which may induce sliding failure once the height exceeds a critical value. Therefore, estimation of the maximum dumping height is crucial to the life-cycle use of a waste dump. However, published information about the maximum height of mine waste dumps are extremely rare. In this study, the maximum dumping height is estimated based on the strength-reduction technique by numerical simulations. The influences of dump geometry and properties on the maximum height are investigated. The results show that the maximum dump height decreases as the dump slope inclination angle α or the unit weight of dump materials γ increases, but decreases when the shear parameters of dump materials (cohesion c and internal friction angle ϕ) increase. The maximum height starts to increase with the ground inclination β when shear failure occurs at the interface between the dump and the base. Furthermore the effects of the dump width B, Young’s modulus E, and Poisson’s ratio μ of dump materials on the maximum height are almost insignificant. Good agreement was found between numerical results available in the literature and those obtained in this study.

Oct 1, 2022

"Chairman: Professor J. de V. Lambrechts Rapporteur: Mr R. HempPapers:Computer-aided design of a flash smelting installation by M. A. T. Cocquerel, R. T. Gates and L. A. GreenPlanning of mine ventilation by E. U. Reuther and A. DohrnenCoal mine ventilation systems in the U.S.A. by R. Stefanko and R. V. Ramani Heat flow models in ventilation planning by A. J. Dickson and A. M. StarfieldThe first of the papers in the session dealt with a flash smelter installation, while the remaining three papers dealt with mine ventilation. In view of this the Chairman proposed that the paper on flash smelting be introduced and discussed first, after which the remaining three papers would be introduced followed by discussion on all three.Dr Cocquerel, who presented the first paper, used some typical flow diagrams to illustrate the process and stated that the program considered only steady-state operations and did not take into account the dynamical changes. Subjective judgment was necessary for the preparation of input data and some degree of user appreciation was required.Dr Cocquerel said that no work bad yet been done on an optimization program, but that this was being considered. Such a program would require a large amount of physical and chemical data which were not yet available. The variables to be optimized were the energy and material consumptions and the loss of metal in the slag.The Chairman opened the discussion by asking Dr Cocquerel if he could give a brief description of the flash smelting process for the benefit of those not familiar with the subject. Dr Coquerel replied that in the Outokumpu process con¬centrates were injected directly into the furnace, and that the process was somewhat analogous to flash distillation or evaporation processes, but was perhaps closer to the burning of pulverized fuel.The process had two distinct advantages. First, the heat evolved in the smelting reaction was used to heat the furnace, which resulted in less fuel consumption, and, second, the effluent gases were cheaper to treat than the effluent gases from other pyrometallurgical processes. This was important particularly in view of the current interest in pollution problems.Mr P. Marais thought that the authors had done themselves an injustice by not including details of the very complex processes taking place in the furnace."

Jan 1, 2014

The Annual General Meeting of the Institute was held in Kelvin House, Johannesburg, on Wednesday, August 14th, 1974. Mr P. W. J. van Rensburg (President) was in the Chair. There were present 56 Fellows, 21 Members, 2 Graduates, 5 Associates, 16 Students, and 58 Visitors, making a total of 158. The President declared the Meeting open at 4.08 p.m. OBITUARIES The President: Ladies and gentlemen, before we start the business of the meeting, it is my sad duty to announce the deaths of the following members of the Institute since our last meeting: Dr O. A. E. Jackson, Honorary Life Fellow and Past President; C. Airth, T. L. Blunt, A. E. Frazer, C. L. Lamb, and K. Richardson, Life Fellows; and J. T. Beaumont, Fellow. As you know, there were a number of other deaths during the year, which were reported at previous General Meetings of the Institute. 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. MINUTES The President: Ladies and gentlemen, the next item on your agenda is confirmation of the minutes of the General Meeting and Special General Meeting held on May 22nd, 1974. These will be published in the August issue of the Journal, and, since you have not yet received this, I must ask that they be held over to the next General Meeting. WELCOME The President: It is a very pleasant duty for me to welcome many members of our Institute and our guests, among whom we are particularly pleased to see the President of the Chamber of Mines, Mr Dolf Schumann, who is also Honorary President of this Institute. Mr Schumann, we are extremely pleased to have you with us today. And, we welcome an old friend of ours, Mr Dillon, Minister of Mines in Rhodesia, who has come down for our Annual General Meeting. Mr Dillon, we are very, very pleased to see you here this evening, and we look forward to seeing Mrs Dillon a little later. And we have with us, too, the presidents or representatives of many of our sister and brother associations, institutes, and societies. In particular, we welcome Mr Mike Gericke, President of the South African Council of Professional Engineers, and Professor Midgley, President of A. S. and T. S. We are also pleased to welcome the Presidents of the Mechanical Engineers, Electrical Engineers, Certificated Mechanical and Electrical Engineers, the Civil Engineers, the Joint Council of Scientific Societies, the Mine Ventilation Society, the South African Association of Consulting Engineers, the Association of Mine Managers, the Institute of Foundrymen, the Institute of Welding, the Federation of Societies of Professional Engineers, Mine Surveyors, Production Engineers (London), and the Institute of Production Engineering. We are very glad, too, to have with us a visitor from England, Professor Raynor and Mrs Raynor. Professor Raynor is Professor of Metallurgy at Birmingham University, and a very well-known metallurgist in Britain. We also have with us the Chairman of the Ferro-Alloys Association. We are expecting the Chairman of our Witbank/Middelburg Branch, the Chairman of the Engineers' Liaison Committee, Pretoria, the Director of the Witwatersrand College of Technical Education, and, of course, our old friend, Mr Eric Boden, the Manager of A.S. and T.S. It is a very great pleasure to have with us a number of persons who will receive honorary Life Fellowship at this meeting, and there are some Gold Medal winners and winners of our Student Prizes. We have apologies from a number of people who are away on business, and unfortunately some are ill. But we are extremely pleased to see those of you who are here, and we are also very pleased to see so many ladies. We expect to see many more of them later this evening, at our Cocktail Party. MEMBERSHIP The President: I have pleasure in announcing that, their names having been published in accordance with By-Law 5.2.2., the following have been elected by Council to membership in the following grades Fellows: B. Collins, D. W. Dixon, J. P. Dreyer, A. T. Hudson, and W. W. Pearce. Members: A. T. Fisher and I. F. Nagy. Associate Members : P. D. de Bruyn and H. C. Iverson. Graduates: D. P. O'Shaugnessy and M. F. Sadler. Associates: R. J. Bushell and A. MacDonald. Students : I. J. Barker, P. J. Charter, J. P. de Witt, G. S. Esterhuizen, N. Green, P. M. Jenner, M. J. R. Meyer, A. P. Nicol, W. J. C. Pothas, B. J. Robbetze, N. T. Sutherland, B. A. Statham, C. R. Thomas, N. C. Webb, M. Salamon, R. G. Jurd, and M. McChesney. Transfers to other grades of membership include the following: Member to Fellow: B. W. Holtzhousen. Graduate to Member: T. S. Schultz. Associate to Associate Member: C. L. Jordaan, H. J. L. Tomlinson, J. E. Forbes, G. H. S. Bamford, T. F. Carswell, J. W. Breidenhann, J. R. Garbutt, and L. S. Gibbs. Student to Graduate: C. J. Faueonnier and B. Lund. Student to Associate : G. P. Gooding. We welcome these new members

Jan 10, 1974

By T. M. Louw, L. Auret, S. M. Bradshaw, F. F. Noelle

Modern industrial processes undergo frequent process state shifts due to changes in demand, feedstock or maintenance operations. Multimodal continuous process monitoring is therefore required for effective plant operation. Steady state analysis is a key component in effective multimodal monitoring. Various issues still remain in determining the starting and ending times of transition states. High dimensionality of process data is a characteristic that makes it difficult to select variables to consider when conducting steady state analysis. In order to address these problems, steady state detection on the principal component space is proposed. First, data undergoes principle component analysis to reduce dimensionality, then existing multivariate steady state detection algorithms are applied on the principle component scores. A novel algorithm, threshold PCA-SSD, is proposed and compared to an existing technique for steady state detection. The algorithms are investigated on high dimensional synthetic data Keywords: Multimode process, steady state detection, principle component analysis

Jan 1, 2020

By D White, L. Lorenzen

Sampling and metallurgical testwork during various phases of engineering studies is of paramount importance for a robust processing plant design. When developing a process flowsheet, risks in achieving desirable financial outcomes are minimised by ensuring that appropriate sampling and adequate metallurgical testwork support the engineering and cost estimation at each phase of project development. The quality and type of samples used for metallurgical testwork are just as important as the metallurgical testwork itself. The key characteristic required of any sample is that it represents some defined portion of a mineral deposit. Representivity should consider the spatial orientation, lithology, alteration, degree of oxidation, mineralogy, and competency of the ore such as hardness and abrasiveness. Statistically representative sampling procedures and an appropriate metallurgical testwork program should be designed to bring metallurgical understanding up to feasibility study standard and to give a basis for process plant design. The authors have observed that the quality of sampling and quantity of metallurgical testwork carried out during the various phases of engineering studies are often insufficient to truly support a robust plant design. Some designs are based on benchmarks of apparently similar ore bodies or rely on buoyant metal prices supporting cash flows until rectifications can be implemented. The paper will discuss important aspects of sampling and testwork required for engineering studies in designing process plants. Keywords: Sampling, metallurgical testwork, studies, design

Jan 1, 2020

By H. von Blottnitz, B. E. Isheloke

Mining is a significant economic activity in most Southern African Development Community (SADC) countries, and mineral beneficiation has been identified, and controversially discussed as one of the possibilities for industrialisation. With many member countries being economically too small to muster the human and financial resources which beneficiation requires, the recently adopted Regional Mining Vision (RMV) envisages interventions at a regional level. An opportunity arose to ask industry role players to what extent the SADC appears to support regional beneficiation policy interventions undertaken by member countries, and what the challenges are in undertaking beneficiation regionally, as a complement to, or substitute for country-specific beneficiation policies. Twenty-five semistructured interviews were conducted with experts from SADC member countries during the 2019 Mining Indaba. Participants were divided on whether beneficiation should be carried out nationally or in the SADC region. While beneficiation could support value-keeping, key challenges were found to be infrastructure development (i.e. energy, water), scarce skills, access to technology and related costs, but also lack of free trade and movement. We submit that a more integrated beneficiation strategy for the SADC region, as is being developed through the RMV, would indeed be relevant in the future. Keywords: Mineral beneficiation, regional integration, beneficiation policy interventions, African mining vision, mining, SADC

Jan 1, 2020

By M. Karsten

Platinum mines in the Bushveld Complex are located in areas with a high geothermal gradient. This means that, compared to, for example, gold mines of the Witwatersrand region, high rock temperatures are encountered at relatively shallower depths. Thus air cooling and refrigeration need to be considered at early stages in mine development. Another factor that influences air cooling and ventilation requirements is the use of trackless diesel equipment for loading and hauling broken rock. At shallower depths it will be more cost-effective to locate the cooling and ventilation equipment on surface, whereas for deeper mines the more cost-effective option is to locate cooling equipment underground. For intermediate depths, trade-off studies need to be undertaken to determine the optimum mix between more cooling and less air or more air and less cooling, as well as the optimum location for this cooling equipment. Factors that are taken into account include power requirements, positional efficiency, and additional infrastructure requirements. Traditionally the approach has been to ventilate ?all of the mine all of the time?. However, with increasing power costs and growing pressure to ensure sustainability, this strategy must be modified to apply ventilation and cooling on demand. In other words, both cooling and ventilation equipment should be operated only when needed and should be adjusted to the demand at the time. Obviously there will be areas that will need to be ventilated (and cooled) continuously (for example, for dilution of flammable gases), but this can be built in to the overall strategy. In addition, in devising ventilation on demand (VoD) strategies, occupational criteria relating to exposure to gases, noise, and heat need to be taken into account. This paper discusses options available for implementing energy-efficient ventilation and cooling systems and suggests ways of changing traditional thinking in the overall ventilation and cooling of mines. Efficient ventilation and cooling designs can play a major role in improving sustainability and reducing energy costs and carbon footprint.

Jan 1, 2012

By A. N. Brown

The Eighteenth International Symposium on the Appli¬cation of Computers and Mathematics in the Mineral Industries was held in London from 26th to 30th March, 1984. The Symposium was organized by the Institution of Mining and Metallurgy under the leadership of Mr M.J. Cahalan, Chairman of the Organizing Committee. The venue chosen was the Royal School of Mines, Imperial College of Science and Technology, in South Kensington. Some 300 delegates from all parts of the world attended, which included a delegation from South Africa that numbered about 20 persons. This extremely successful series of international meet¬ings was begun in 1961 in Tucson, Arizona, and has grown in strength and importance over the years. The arrange¬ment of the symposia is regulated by the International Council for APCOM under the Chairmanship of Professor R.V. Ramani (U.S.A.), the other current members being Professor J. Elbrond (Canada), Dr Thys B. Johnson (U.S.A.), Professor Young C. Kim (U.S.A.), Professor D.G. Krige (R.S.A.), Professor A.J. Lynch (Australia), Professor C.T. Shaw (U.K.), Dr A. Weiss (U.S.A.), and Professor F.L. Wilke (F.R.G.). There is no doubt that the enthusiasm and dedication of this small group of people and the excellent working relationship that exists between them are responsible for the continued success of APCOM meetings.

Jan 1, 1984