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"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

By J. le Grange, M. Tullmin, A. Strauss, F. P. A. Robinson, C. A. O. Henning

An experimental feritic stainless steel with a chromium content of 40 per cent was welded by laser and electron beam (EB) welding processes. These techniques were found to be particularly suited to the welding of this alloy in that the impact toughness of the weld metal and heat-affected zone (HAZ) of the laser welds compared favourably with those of the parent aloy. When the EB process was used, the impact toughness of the weld metal was over 180 J/cm2. Grain growth in the HAZ was minimal for welding with these two processes. Corosion tests, conducted in a solution consisting of 20 per cent sulphuric acid and 100 p.p.m. of potassium thiocyanate, and In a highly corrosive industrial solution, indicated that the laser and EB welds were free of sensitization effects, thus confirming the metalographic results.

Jan 1, 1989

By I. M. MacGregor

This paper discusses the possible use of petrological data and proximate analyses in the prediction of cutting forces for coal. It is restricted to the development of univariate predictors based on data from thirteen collieries in five major Transvaal and Orange Free State coalfields and three coal provinces. The aim of the work was the identification and development of the best predictors of mean peak cutting force and Hardgrove grindability index from among the independent variables evaluated. The data, which were obtained by use of the penetrometer developed by the Chamber of Mines Research Organization, were processed according to the SPSS computer package. The analysis revealed reasonable correlations between the Hardgrove grindability index and (1) the volatiles and vitrinite content in the Vereeniging-Sasolburg and South Rand Coalfields, (2) the contents of vitrinite, vitrinite plus exinite, and minerals plus inertinite in the Eastern Transvaal Coalfield.

Jan 1, 1985

By H. Mulder, M. C. Bekker

The objective of this paper is to describe the research followed in creating a generalized, readiness assessment tool for mining projects. We start by highlighting the need for the assessment tool and then progress towards explaining the methodology followed during the study. The selection and finalization of the list of elements, sections, and categories that make up the unweighted values are described, followed by a summary of the weighting process applied. The outcome of this process is a weighted readiness assessment tool for mining project studies. The main benefits of the tool are that it will guide decision-makers and project managers through the definition phases of the project and improve the likelihood of project success.

Jul 2, 2022

NIM reports Report No. 1615 Fluorspar pellets. A survey of the world market and an assessment of future South African production. Report No. 1621 Correction for matrix effects in the analysis of solutions by X-ray-fiuorescence spectrometry. Notices Questionnaire on Technicians The Department of National Education's committee of enquiry into the education, training, utilization, and status of engineering technicians in the Republic of South Africa was established as a result of Resolution 6.3 taken at the Sixth Conference on Engineering Education: The Education and Training of Engineering Technicians. Vraelys oor Tegnici Die Departement van Nasionale Opvoeding se komitee wat ondersoek instel na die opleiding, gebruik en status van ingenieurstegnici in die Republiek van Suid-Afrika is gestig as gevolg van Besluit 6.3 wat geneem is tydens die Sesde Konferensie oor Ingenieursopleiding: Die Opleiding van Ingenieurstegnici. Competition for Student Members of the South African Institute of Mining and Metallurgy Each year the Institute offers a prize (or prizes should the entries warrant it) of up to R100 for the best paper or dissertation on a topic appropriate to the interests of the Institute. The competition is open to all Student Members of the Institute.

Jan 8, 1974

"Chairman: Prof A. E. H. BLEKSLEY Rapporteur: Prof J. ELBRONDPanel Members: Prof J. C. Griffiths, Prof T. E. Hawkins, Mr A. C. Langton, Mr M. Splaine, Mr A. WeissThe reasons for failure of computer applications in the mineral industry and the direction of future developments.The Chairman opened the discussion by elaborating on the disappointment felt by some authorities with the lack of progress in the application of computers in the mineral industry during the last ten years, and posed the question to the panel : 'Do you agree that the computer age has not come up to expectations?'Mr Langton said that although there seemed to be a tremendous amount of brainpower applied to the theoretical side, he thought that the production men had not got all the help from computers that could have been given to them. The computer, said Prof Griffiths, is as yet a new tool which should not be used to do old things in old ways. To learn to use the computer will take time. After all, he said, it had taken 400 years after the introduction of the printing press to achieve general literacy, and perhaps it will take 40 years after the introduction of the computer to achieve `numeracy'.In Mr Weiss' view, the reason for the feeling of disappoint¬ment lay in the focussing of attention on the computer. The blame, if any, lay with the people surrounding the computer, that is, the analysts and programmers, to whom the emphasis should be shifted.Prof Hawkins said that he thought that some applications of the computer in the mineral industry had been successful, such as, for example, the compilation of payrolls. Reasons for failures in other areas were to be sought in the fact that the people connected with computers had failed to realise that they were merely part of a system. They had not understood the power structure of the organization which their work tended to change, and were therefore not prepared for the inevitable conflict with the production men.In Mr Splaine's view the production man had not received the assistance he could have had from the computer people because he may possibly not have allowed this to happen.Prof Bleksley concluded from these opinions that the promise which computers had ton years ago had not been fulfilled and added that the opinions expressed by the panel had intruded on his next question which was: 'Is the reason for this that people are involved?Prof Hawkins elaborated on his previous theme, namely, that of computer people in relation to management. Com-puter people, he said, were trying to impose change on management but were not prepared to share the responsibility for these changes. In fact, they wanted their work to be distinct and separate, and, as far as management was concerned, changes would be made when management believed that these would be less agonizing than no change at all."

Jan 1, 2014

By N. C. Joughlin, D. K. Hallbauer

The size distribution and morphology of gold particles in Witwatersrand reefs and their crushed products by D. K. HALLBAUER, Dr. rer. nat., Dipl. Min. (Visitor) and N. C. JOUGHIN, B.Se. (Eng.), Ph.D. (Rand) (Member) Undistorted gold particles were obtained from samples of a variety of Witwatersrand reefs by dissolution of the quartz in hydrofluoric acid. The size distribution of the gold particles and their shapes and association with thucholite and pyrite are discussed. Gold particles with a natural flat, plate-like appearance occur in varying proportion in all reefs. The effect of a number of different comminution processes on the gold particles was investigated, and the shape of gold particles in mill pulp from a number of mines was examined.

By R. M. Mashishi, T. Malehase, O. J. Okonkwo

The concentrations of selected trace elements (As, Cd, Hg, and Pb in run-of-mine (ROM) coal, discard, and coal product were investigated to assess the efficiency of beneficiation in reducing trace element concentrations and ascertain any implications regarding environmental compliance to regulatory frameworks. Samples were collected from a colliery in Mpumalanga Province twice a month for a period of 24 months. The samples were ashed to approximately 0.21 mm, then digested in a mixture of 70% HNO3 and 40% HF and analysed using inductively coupled plasma-mass spectrometry (ICP-MS). Except for Pb, the mean concentration of all elements decreased from the ROM stage to the coal product stage. The order in which trace elements occurred from the highest to lowest throughout the production chain was Pb>As>Hg>Cd. With the exception of Cd, the mean trace element concentrations in the discard were above the total concentration threshold (TCT) set for landfill disposal. The As, Hg, and Cd concentrations in the product were well below the thresholds for all land uses. However, Pb concentrations in the product coal were above legal limits, which is of concern with regard to environmental compliance and the performance and marketability of the product.

Dec 13, 2023

By D. D. Marsden, L. E. Kun

Although a regulation is in force that all water used underground shall be free of bacterial contamination, in practice it is often very difficult to accomplish this. The standard method of disinfection m South African mines IS treatment with calcium hypochlorite, although liquid sodium hypochlorite is used at a few sites. Primarily because the process depends on human control for the addition of the hypochlorite and the regulation of its now, it is frequently found difficult to disinfect mine water adequately and continuously. In many marine environments, chlorine generated by the electrolysis of seawater in its passage through an electric cell is used for disinfection. The generation procedure is continuous and needs no human control except for occasional checking of the equipment. This paper describes the successful implementation of the process, suitably .modified, .at four underground sites. After severe scaling problems had been overcome, a procedure resulted that chlorinates considerably more effectively than the previous system (dosing with calcium hypochlorite), and that has a lower amortized operating cost.

Jan 1, 1981

By J. Cilliers, R. Seitz, D. Drinkwater

Mineral processing produces a saleable product from high-cost ore. The Mineral Processing Engineer must constantly improve the separation to create the most value from the ore and reduce the associated costs. Graduate Metallurgists (or Chemical Engineers) have had the university theoretical training required, but often are illprepared to perform their plant roles. The in-work Metcelerate programme was designed specifically to develop the practical skills that Mineral Process Engineers require, by combining three key elements: 1. Knowledge transfer through self-paced, on-line training; 2. Practical skills acquisition through assessed, practical plant exercises; 3. Skills development through online tutorials. A final process improvement project adds significant value to the operation that far exceeds the training cost. Experience from Metcelerate clients has indicated improved staff retention, greater confidence, and pro-active process intervention.

Jan 1, 2023

By A. Atta-Quayson

Since 2012, Ghana has been implementing local procurement regulations in the mining sector to broaden and deepen linkages between mining and other sectors of the economy. The regulations have been implemented in collaboration with the mining industry. This paper offers an in-depth analysis of how the local procurement regulations and related initiatives have been implemented so far. Primary data gathered with semi-structured interviews and secondary sources of data indicate a steady improvement in both in-country procurement and local manufacturing of inputs for the mining industry. There are, however, some challenges relating to tariff structure and support (financial and technical) for local suppliers and manufacturers to meet high standards and demands of the mining industry. This calls for a well-thought-out strategy and programme of activities to sustain and improve on progress made.

Feb 2, 2022

The Technical Programme Committee-Metals Technology of The South African Institute of Mining and Metallurgy, in association with its Vaal Triangle Branch, held a one-day colloquium on 18th April, 1989, the theme being 'Ferous Pyrometalurgy: A Challenge for South Africa'. The venue was the Auditorium 100 at the campus of the Vaal Triangle Technikon in Vanderbijlpark. Project and contract management A Project and Contract Management Conference is to be held on 19th and 20th September, 1989, at the C SIR, Pretoria. Powder metallurgy The PM 90 exhibition is to be held in Wembley, London, from 2nd to 6th July, 1990. The wide range of powders, processing machinery, and powder-metallurgy components at the exhibition will reflect the growth in this highly specialist industry. Castings and forgings Exhibition organizers, FMJ International Publications Ltd, are set to build upon the success of Castings & Forgings '88, which was held as a joint event with Pat- Cast '88. Castings & Forgings '89-with Pat-Cast '89- has already generated a high level of interest, which has been reflected in the demand for stands. Furnaces FURNACES '90, the eighth in this series of exhibitions for the thermal-processing industry, will be held in Solihul, West Midlands, England, on 6th and 7th March, 1990.

Jan 1, 1989

The Annual General Meeting of the South African Institute of Mining and Metallurgy was held in Kelvin House on Wednesday, 25th August, 1976. Dr R. E. Robinson, (President) was in the chair, and declared the meeting open at 16h00. Obituaries The president: It is my sad duty to announce the death of the following members of the Institute : P. A. Creewell, Life Fellow; A. S. Davis, J. S. Hay, P. O. Large, N. McCaskell, and H. G. M. McKerrow, Life Members; C. L. Bererge, Fellow; T. Bulloch, G. Douglas, R. W. Forrester, and C. G. P. Sack, Members; P. R. Garcia, W. A. Naude, and J. P. Slager, Associates. As a mark of respect to the memory of the deceased and in sympathy with the bereaved, I ask you to rise and observe a few moments' silence. Minutes The President: May we confirm the minutes of the General Meeting held on March 17th, 1976, as published in the June issue of the Journal? Agreed. Welcome The President: It is my pleasant duty to welcome a number of guests and distinguished visitors this evening. First, I would like to welcome Mr R. Plumbridge, the President of the Chamber of Mines, and Mrs Plumbridge. We have had very close co-operation with the Chamber of Mines, and it is particularly gratifying that Mr Plumbridge has had time to be with us this evening in spite of very heavy engagements. Ook 'n spesiale woord van verwelkomirg aar mrr. N. Orsmord, die Staatsmyringerieur, en mev. Orsmord. Ors wil hierdie geleertheid gebruik om mrr. Orsmord geluk to wens met sy aarstellirg as die Staatsmyrirgerieur en die hoop uitspreek dat dit baie jare van samewerkirg met hierdie Irstituut sal beteker. We also welcome guests who, in one way or another, have been able to attend most of our Annual General Meetings, the Honourable I. B. Dillon, the Minister of Mines of Rhodesia, and Mrs Dillon. Once again we welcome them most heartily to our Annual Meeting. I would also like to welcome the representatives of many of our sister institutions : the Honorary Treasurer of the AS & TS, Mr D. G. Maxwell; the President of the South African Institution of Mechanical Engineers, Mr A. R. Adams; the Vice-President of the South African Institute of Electrical Engineers, Mr K. A. H. Adams, and Mrs Adams; the President of the Institute of Certificated Mechanical and Electrical Engineer s, Mr Martin and Mrs Martin; a member of the Executive of the South African Institute of Civil Engineers, Professor G. Bright ; the President of the South African Chemical Institute, Mr Vic Shuller, and Mrs Shuller; the President of the Institute of Welding, Professor F. P. A. Robinson, and Mrs Robinson; the President of SACPE, Mr M. R. Gericke ; the President of the Institution of Metallurgists, South African Branch, Mr D. R. Allen; the President of FSPE, Dr P. J. D. Lloyd, and Mrs Lloyd ; Mr A. J. H. Pole of the Association of Mine Managers, and Mrs Pole; and Mr M. D. Hoskin of the South African Institute of Foundrymen. A special word of welcome to Mr G. C. Young of our Orange Free State Branch, and Mrs Young ; and to Mr E. J. Jackson of our Witbank/Middelburg Branch. We have great pleasure in welcoming Dr F. M. Naude, the Scientific Adviser to the Prime Minister, and Dr W. C. J. van Rensburg, Technical Director of the Minerals Bureau. The latter is a new organization, and we hope their attendance here this afternoon forecasts a long period of co-operation between the Minerals Bureau and this Institute. Ook wil ek hartlik hier verwelkom die Rektor van Die Randse Afrikaanse Universiteit, professor G. van N. Viljoen. Ors het baie noue samewerking met die Universiteit gekry, en ek wil ook bier verwelkom die twee verteenwoordigers van die Geologiese-afdeling en die Chemie-afdeling, naamlik, dr C. Roering en professor G. W. Holzapfel. Last, but by no means least, a word of welcome to a very old friend, Mr Eric Boden, the Manager of AS & TS. To all our guests, a very hearty welcome to this our Annual General Meeting. Membership The President: It is required by our Constitution that I announce the names of a number of candidates who have been elected to various grades of membership. The list is a very long one, and I suggest that we simply record that these names will be published in the Journal. Any one who wishes to comment on these members should do so in writing to our Secretary. Agreed. Fellows: G. Paterson, P. H. Adler, F. W. G. Schoning, J. P. de Villiers, F. I. de Waal, J. R. H. Shaw. Members: C. J. Slavin, P. J. Perkins, R. J. I. Butler, A. M. Hattingh, C. E. Alvey, J. A. Engelbrecht, P. L. Gouws, J. P. Martin, J. F. Taylor, K. A. G. Blendulf, A. R. Gibb, W. E. Smith. Associate Members: D. R. Broderick, D. F. Cilliers, D. N. Stuart, P. Kraus, B. G. Pinder. Associates: D. E. Gibbon, D. F. Jacobs, R. F. W. Swanepoel, R. D. H. Bebb, H. H. Vernall, R. D. Gibson, J. P. van Wyk. Graduates : A. N. Morris, D. J. Payne, G. S. Worthington, A. S. Dennison, A. R. Godfrey, N. Holloway, W. J. Rankin, G. S. Lyndon, R. J. van Proctor, J. J. Versluis, G. M. Miller. Students: B. J. Rabie, G. D. Webber, W. L. Blair, I. D. Mathews, K. McVey, S. W. Beer, R. W. J. Bentley,

Jan 10, 1976

Tests were carried out in a Hallimond microflotation cell and a Denver D12 cell on typical residue material from a gold mine in the Orange Free State (South Africa), in which 50 per cent of the kerogen was larger than 100 µm in size. Although kerogen is naturally hydrophobic, the observed unexpectedly poor flotation reponse may be due to occlusion of the kerogen by a slime coating and subsequent depression of the slime by guar gums. The recovery of gold from samples spiked with kerogen increased, with no significant reduction in grades, when a petroleum-based collector and tetrasodiumpyrophosphate (a dispersant) were used.

Jan 1, 1985

It is shown that, when a flat-bottomed indentor is pressed into the surface of a strong rock, the normal force necessary to cause failure of the rock is reduced substantially if a shear force is applied to the indentor. A mathematical analysis is described, which shows that higher stresses are induced in an elastic material close to the free surface of the material ahead of a punch when a shear force together with a normal force is applied to the punch. Therefore, failure of the material would occur with lower forces applied to the punch. Stress trajectories show that fractures develop in the rock along lines of maximum principal stresses.

Jan 1, 1978

By A. Miller, M. Bétournay

The main objectives of the Mine Mechanisation and Automation program (MMAP) are to enhance health and safety in underground mining operations, facilitate mechanization and automation in narrow- vein and deep mines, provide sound science to regulatory agencies and improve mine profitability. The program, which has a unique underground and surface industrial scale facility, is involved in many multi-partner projects, like hydrogen fuel cell applications, electrification and hydraulification of underground mines, reduction of noise and vibration, miner location device, explosive-free blasting and hoisting. The paper presents an overview of the Mine Mechanisation and Automation Program of Natural Resources Canada and some of the main projects.

Sep 1, 2001

By F. P. Agterberg, A. G. Fabbri

"A statistical analysis was done on the locations of 718 copper and 1 257 gold deposits in Abitibi. This area of about 20 000 square miles is one of the better-explored metal-producing areas of Canada.Patterns of clusters were studied by harmonic analysis. Several two-dimensional power spectra showed a number of distinct peaks. Sets of crest lines for patterns of interfering waves were constructed on the basis of these peaks. They pass through elongated clusters of deposits which are spaced more or less equally. For copper these periodic regularities in location may coincide with geological structures largely of Archean age (major fractures and sedimentary belts indicating synclinal structures). A directional relationship with swarms of diabase dykes of known ages and distinct attitudes indicates that the gold mineralization is, in part, younger than the copper mineralization."

Jan 1, 2014

By J. R. de Wet

The behaviour of mild steel in aqueous cyanide solutions similar to caustic cyanide elution solutions was investigated at high temperature in electrochemical experiments. The anodic polarization diagrams of mild steel indicated that steel may undergo active dissolution under these conditions. The rare occurrence of gold plating in practice is the result of the limiting of the anodic dissolution of the steel by the presence of a passive layer on the steel. This passive layer is stable only in a certain potential range, and the free corrosion potential attained determines whether the steel will be passive or active. For conditions typical of elution columns, several corrosion potentials are possible, depending primarily on the initial condition of the steel and the concentration of oxygen in the solution. If these conditions result in the formation of a passive layer on the steel, changes in concentration and temperature will not necessarily result in plating since the layer may exist in a metastable form.

Jan 1, 1993

By J. van der Walt, A. Whillier

Gravity-fed water systems in mines by A. WHILLlER, Pr. Eng., Se. D. (M.I.T.) (Fellow) and J. VAN DER WALT, Pr. Eng., B.A. Hons. (Bus. Admin.), Ph.D. (Eng.) (Visitor) South African mines often experience significant losses in production because of recurring shortages of water at work places as the result of underground dams running dry. Similar shortages have occurred during fire-fighting operations, and now, with the use of cold service water to aid in the cooling of mines, it is even more necessary that such shortages should be prevented. This paper draws attention to the primary cause of such water shortages, and an outline is given of some of the fundamental hydraulic principles that must be followed in the design of gravity-fed water-supply systems on mines.

Jan 4, 1977

By M. Asghari, R. Amiri, A. Haratian, M. Noue Parast, S. Haji

Today the roller screen has a wide range of applications in the steel-making industry. It is used for screening of green pellets before using the kiln. Since the appropriate size of a green pellet is -16+9 mm, there are different gaps between rollers that make green pellets classified in three categories: -9 mm (undersize), -16+9 mm (onsize) and +16mm (oversize). The efficiency of a roller screen is specified according to the weight percent of undersize in onsize as a fine material, and weight percent of onsize in oversize (loss). This efficiency is influenced by different operational parameters such as roller diameter, roller speed, and roller gap, material type of rollers and inclination of roller screen. This study investigates the effect of different material types of rollers in efficiency of Ardakan roller screens, located in the Yazd province of Iran. The rollers of the existing roller screens in this pelletising plant are made of polyurethane which according to this investigation, has a maximum lifetime of about six months. Operating the polyurethane rollers beyond its lifetime generates serious problems such as high wear of rollers, and consequently, material buildup on the roller surface which then significantly decreases the roller screen efficiency. So, after examining different roller materials, stainless steel 304 with higher surface roughness to help pellets move properly on the roller screen surface was selected as a solution to this problem. The new roller screen was constructed by Fakoor Meghnatis Spadana (FMS) and replaced the previous one. In this way, the maximum capacity of the roller screen was increased about 17% and the roller screen efficiency was increased about 15%. Keywords: Roller screen, green pellets, efficiency, onsize, operational parameters

Jan 1, 2020