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By M. L. Bakker

Keywords: Pyrometallurgy, top submerged lance (TSL), nickel, PGM, calcium ferrite, lime ferrite The ISASMELT? top submerged lance (TSL) bath smelting process was developed in Mount Isa, Australia by Mount Isa Mines Limited (now a subsidiary of Xstrata plc) during the 1980s. By the end of 2011, the total installed capacity of the ISASMELT? technology will exceed 9 000 000 metric tons per year of feed materials in copper and lead smelters around the world. Commercial plants, operating in Belgium and Germany, are also batch converting copper materials in ISASMELT? furnaces. This TSL technology is equally effective for continuous converting processes, whereupon it is called ISACONVERT?. This paper presents the recently patented ISACONVERT? process for the continuous converting of nickel and Platinum Group Metal (PGM) containing mattes using the calcium ferrite slag system. The paper focuses on the potential application of the ISACONVERT? technology to existing nickel and PGM smelting complexes.

Jan 1, 2011

By V. Labiouse, M. Jaboyedoff

GIS documents are of great interest for a quick and low-cost determination of areas endangered by rockfalls. They allow (i) the detection of potential instabilities from steep slopes and cliff areas, and (ii) the preliminary estimation of potential run-out areas by means of a so-called cone method. After the presentation of the tools used to compute these areas, the paper focuses on two methods developed for a preliminary hazard mapping, one at regional scale and the other at local scale. Mittels GIS-Dokumenten können von Steinschlag bedrohte Gebiete schnell und kostengünstig ermittelt werden. Die sogenannte Kegelmethode erlaubt die Erkennung potentiell instabiler Zonen von Steilhängen und Felswänden sowie eine erste Einschätzung der möglichen Reichweiten. Nach der Vorstellung der zur Berechnung der bedrohten Gebiete benötigten Hilfsmittel stellt der Artikel zwei Methoden zur vorläufigen Gefahrenkartierung in lokalem und regionalem Maßstab vor. Les SIG sont très intéressants pour une détermination rapide et peu onéreuse des zones affectées par des chutes de blocs. Ils permettent une détection des zones potentiellement instables et une estimation sommaire des zones de propagation des blocs par une méthode dite des cônes. Après la description des outils utilisés pour définir ces zones, l’article expose deux méthodologies élaborées pour un zonage préliminaire du danger, l’une à l’échelle régionale et l’autre à l’échelle locale.

Jan 1, 2003

By Dennis Van Heerden

Southern Africa has a long history of underground hard rock mining dating back to the late 1800?s. The rock support of underground excavations has significantly changed during this period, due to improved technology, experience gained and rock support requirements by mining and geotechnical engineers. This paper examines the available underground rock support methods in Southern Africa with emphasis on the types and characteristics of: - Rock bolt types. - Rock bolt and long anchor grouts. - Thin-sprayed liners. - Sprayed Concrete. - Ground consolidations through injection methods. - Cavity and void filling with aerated cement products. [ ]

Jan 1, 2007

By Godofredo F. Barrios

For years urethane screen surfaces have been used in a wide range of wet screening applications where openings from as fine as 100 microns and coarser have been used. The purpose of this paper is to expose the reader to new developments in both screen surface and screening equipment technologies which allow an end user to consider urethane screen surfaces for fine screening applications. These technologies allow an end user to use the inherent advantages of urethane with regards to wear resistance while also realizing the benefits that a high oper area urethane screen surface can bring. These benefits include non blinding characteristics and feed capacities that which rival that of traditional stainless steel surfaces. The paper will highlight the features of this patented urethane screen surface technology and the screening machines they are used in conjunction with. There will also be a presentation of case studies of commercial installations where these technologies are utilized. These case studies are from the base metals industry therefore relevance to the conference is direct and not inferred. Included in the paper will also be constraints which must be taken into account when considering urethane screen surfaces such as temperature and chemical attacks. This paper will expose potential end users to a possibility of using screens to achieve extremely accurate size separations in applications where screens were previously not considered. The paper will explain and demonstrate that prior concerns of screen surface blinding, high screen surface consumption rates and large screen surface area requirements can be eliminated by proper utilization of high open area urethane screen surfaces.

Jan 1, 2007

The Gordonsville Operation of Pasminco US Inc. along with the Center for Advanced Mineral and Metallurgical Processing (CAMP) at Montana Tech studied, developed and implemented a pilot-scale hydrometallurgical facility for the industrial recovery of germanium and gallium. This paper describes the joint testing and engineering programme that culminated in this successful process.

Jan 1, 2008

By K. R. P. Petersen

Paper written on project work carried out in partial fulfilment of M.Sc. Eng.(Metallurgical Engineering) degree The interrelationship between mineral liberation and leaching behaviour of a gold ore is ill defined, mainly due to the complexity of both leaching and mineral liberation. This study presents a neural network approach to modelling the liberation of gold bearing ores. A complete mineralogical analysis of unmilled and milled ores, including gold deportment and gangue content are used as inputs to a self-organizing neural net, which generates order preserving topological maps. The arrangement and shapes of these clusters are coupled to unmilled free gold data to predict gold liberation in milled ores (absolute error: 8.1%). Moreover, the self-organizing maps were diagnostic of the quality of data used, indicating that the relationship between particle size and gangue material content requires further investigation.

Jan 1, 2003

By S. J. S. Ferreira

Anglo American Platinum's Khomanani 2 shaft changed over from down-dip mining to breast mining in 2004. The changeover was made to ensure that production targets were met, as it was said that predevelopment for down-dip mining was not fast enough to sustain the required ore reserves; nevertheless, production performance did not increase as expected. In this study a trade-off was performed between down-dip mining and breast mining on the Merensky Reef at Khomanani 2 in order to find the most suitable method for mining the Merensky Reef. Data was gathered by means of a literature survey, underground observations, and interviews with personnel as well as data from various departments on the mine. The two mining methods were studied and then evaluated in terms of the following criteria: safety, mining rate, cost and other factors which were identified as the main drivers of the mine. A scaling system was used to rate the performance of the two mining methods. Analysis of the results shows that down-dip mining and breast mining have the same safety performance ratings. Breast mining has a better mining rate performance than down-dip mining. Breast mining was found to be costly in comparison with down-dip mining, which has a good cost performance rating. The overall ratings of the two mining methods are very similar, with down-dip mining achieving a rating of 76 and breast mining 75.5 out of an optimum 102. Khomanani 2 currently practices breast mining, and with such a slight difference in performance rating between the two methods, it will not be worth changing over to down-dip mining as production is likely to be adversely affected during the changeover. Down-dip mining does, however, have potential for improvement in its performance rating. Further studies focusing on the improvement of the mining rate performance for down-dip mining are needed to see if this potential can be realized. If significant improvement can be made in the performance rating for down-dip mining, a changeover to down-dip mining can be reconsidered.

Jan 1, 2012

Mine wide, underground wireless communications are possible with the use of Ultra Low Frequency (ULF) technology. Due to the propagation through rock of ULF radio signals a relatively small antenna can provide communications coverage over a complete mining operation. Starting as a Personal Emergency Device (PED) for emergency messaging to miners under all circumstances, the ULF communications system has grown to include capabilities of remote control of underground equipment such as pumps and fans and centralised blasting initiation. This technology is now in use on 5 continents having lately made it onto the African mining scene. The paper and presentation will provide the audience with the benefit from international mining know-how in this technology as well as local African experiences. A recent commissioning exercise for example, is expected to pay for itself in electricity savings within a few months. These and other results from practical demonstrations and usage will be covered. This novel technology becomes an integral part of the daily operating infrastructure of a mine with immediate safety and business benefits. It is able to reduce capital expenditure and is designed for ease of routine operational use. The paper will conclude with insights into current R&D for further development of this technology.

Jan 1, 2007

By A. Nel

The gold mining industry in South Africa stands to benefit much from the implementation of the self-directed work team concept. Its introduction implies flatter hierarchical structures, empowerment of the workforce and increased participation. Research indicates that half of the initiatives to implement self-directed work teams, however, fail, and it is therefore imperative for companies to be aware of the factors impacting on the effectiveness of self-directed work teams in order to focus on these early in the implementation phase. The objective of the study was to qualitatively determine these factors. Semi-structured interviews based on the phenomenological method were carried out. The sample included members of, and individuals involved with, self-directed work teams (N= 26) from a large gold mining company in South Africa. Results show that most respondents rated the availability of resources to do their work as the most important factor affecting their effectiveness.

Jan 1, 2006

By A. Ahmed, A. Fathy, M. Eissa, K. El-Fawakhry, A. El-Mohammady

Silicomanganese is widely used as a complex reducer and an alloying addition in the production of various grades of steel due to its economic and metallurgical advantages. It is also used as a semi-product in the manufacture of medium- and low-carbon ferromanganese and metallic manganese. Manganese-rich slag, resulting from high carbon ferromanganese production, has the advantages of high manganese content, high Mn/Fe ratio, low excess oxygen, low phosphorus content, low fine content and low cost. Such slag seems to be very attractive to use as raw materials for the production of silicomanganese alloys. In the present study, experimental heats were designed and carried out to optimise the factors affecting the production process of silicomanganese using manganese rich slag in the charge. The results of pilot plant experimental heats showed that the optimum metallic yield and recoveries of manganese and silicon are obtained with initial slag basicity,(CaO + MgO) / (Al2O3), equals 1.8 by using dolomite as fluxing material and charging quartzite and fluorspar in percentage of 25% and 4% of the blend, respectively. The results showed also that an amount of 30% of coke in excess of the stoichiometric amount should be added. These result are relative for the specific high Al2O3 ores used.

Jan 1, 2004

By L. G. Stolarczyk, J. Duncan

"SynopsisLong before the environmental movement, coal miners were suffering from occupational diseases that became apparent in the later years of service, and especially during the retirement years. Chronic exposure to micro-fine dust in the respirable range (‘float’ dust) causes various lung diseases, referred to as coal mine dust lung disease. In the USA alone, 76 000 miners have died of coal mine dust lung disease since early legislation recognized the issue in 1969. Researchers believe that reducing float dust exposure limits alone will not reverse the increasing incidence of coal mine dust lung disease seen in the current generation of miners. Trace and radioactive metals are concentrated in the thin boundary layers of the coal seam (Roberts, 2013), and hence float dust includes silica and toxic trace metals. The production and quality of coal is also significantly impacted by the presence of these contaminants in the coal. In the combustion process, the trace metals are oxidized and become incorporated in the fly ash and flue gas. Since they are extremely water-soluble, they represent a significant danger to health and the environment. Coal preparation plants and power stations need to mitigate these contaminants as far as is practical, but the simple fact is that most contaminants should have been left un-mined.This paper describes an innovative coal-cutting solution to the longstanding technology gap in mining – the ability to measure uncut coal layer thickness to the boundary rock layer. Because of constant changes in geology, seam thickness, and seam undulation, the horizon sensor must be located in the bit-block of the rotating cutter drum of the mining machine. Contaminants in ROM coal must be minimized at the source – that is, at the rock/coal crushing cone directly under the bit-tips of the cutting drum. Bittip distances to the rock boundary layer must be automatically controlled in real time when mining in a complex and undulating coal bed. Horizon sensing (HS) technology enables the mining machine’s cutting picks to stop at a specified distance from undulating horizons of the boundary rock. The thin contaminated coal layer can be left in situ, significantly reducing the toxicity of the float dust. Preventing the metal picks from striking quartz-containing boundary rock also reduces the occurrence of methane ignitions. HS technology equipped with pick force vector sensing can allow optimization of the cutting pick lacing pattern for minimum coal and rock crushing, thereby reducing float dust. This technology may enable the mining industry to convert from automated machine control to autonomous during coal cutting and loading."

Jan 1, 2015

By Noel C. Joughin

In making judgements on tolerable levels of risk in industry, and in all spheres of life, it needs to be understood that every action gives rise to risk. Without risk, nothing can be done. Without risk, no economy could be advanced. There is a strong tendency to emphasize the risk at work, but persons who are not working are exposed to a different set of risks. Often persons who are not working face greater risks than persons who are working. Simply, in being alive, one is exposed to the risk of an accident, the risk of contracting a disease, and an extremely diverse variety of other risks. According to the Health and Safety Executive of the UK, it is not possible to have a state of zero risk, because ?a state of zero risk does not exist?. Because zero risk is a physical impossibility, it is not possible to design for a state of zero risk in all engineering design. While the strategic target of achieving zero risk is laudable it does not provide any practical guidance to engineers as to what acceptable limits of risk should be. This causes a significant and real problem in the design for and the management of risk. Without meaningful guidelines, engineers, managers and the authorities often find themselves in disagreement. Thus, it has become essential to establish criteria for tolerable levels of risk and unacceptable levels of risk in order to design and manage engineering systems properly.

Jan 1, 2011

By R. D. Hull

Paper written on project work carried out in partial fulfilment of B.Sc. (Eng.) (Mining) degree As a partial fulfilment for the degree of B.Sc. (Eng) (mining) at the University of the Witwatersrand, a dissertation was to be completed in the mining industry. This was done at Finsch mine, with the purpose of determining the best solution to the required secondary breaking problem. In order to complete the study of the secondary blasting method available for use in the new block 4, cave mining method at Finsch mine the following problem statement was identified and solved ?The methods currently in use, for the secondary breaking of oversize rocks at their source in the current production levels, are to be investigated, and their applicability to the new block 4mining project determined?. To effectively achieve this problem statement above; time was spent researching and investigating, in depth, the methods that are currently in use at both Finsch and Koffiefontein mines; so as to gain practical knowledge of these. The methods were identified and independently evaluated, taking into consideration factors such as costs of the equipment, time to break oversize rocks, advantages, disadvantages, safety and labour requirements, etc. This in turn then allowed for a direct comparison between the methods and the decision as to the best to apply to the new block 4 production level. The methods that were investigated included: ?Concussion blasting, where concussion bombs and lay-on charges are used to break hang-ups and boulders. ?Drill and blast methods, where holes are drilled in large rocks and charged manually with explosives. ?Emulsion secondary blasting, which is a new project in use at Koffiefontein mine from African Explosives Limited. ?The Ro-BustTM breaking system, a hydro-fracturing breaking system. Once all the methods had been evaluated and compared it was found that the Ro-BustTM Breaking system was the most applicable for the breaking of boulders, with, the Emulsion Blasting System being used for hang-ups. Further information and the more in-depth version of this report, is stored in the resource centre at De Beers?Finsch Mineand the School of Mining Engineering WITS University.`

Jan 1, 2002

By J. Kempken, T. A. Schreiter, R. Degel, H. Schmieden

Keywords: Pyrometallurgy, SMS Demag, Germany, submerged arc furnace, ferro alloys, non-ferrous, FeCr, FeNi, FeMn, copper, cobalt, slag cleaning, PGM, rectangular furnace After a short summary of the SMS Metallurgy part of the SMS group, the paper will focus on Submerged Arc furnace technology. After general aspects of furnace design, the focus will shift to different applications and their specific furnace requirements. Finally, a state-of-the-art design tool as well as a new invention to improve slag-cleaning technology will be featured.

Jan 1, 2006

In order to deliver a quality shotcrete and concrete product underground for the extensions to the Cullinan Diamond Mine operations it was decided to develop a new, simpler concrete product to meet underground support requirements. The aim was to develop a concrete product that not only reduced costs but also met the performance criteria of the current range of concrete products used on Cullinan Diamond Mine, a 25, 45 and 60 MPa concrete and a fibre reinforced wet shotcrete. The concrete product batching and delivery system was to be from surface as opposed to the current underground batching systems. The operational principle was to include an automated surface batching plant with delivery of the concrete product to a borehole containing suspended pipelines delivering to an underground storage facility from where the product is delivered to the working area by further pumping or agicars. Keywords: concrete, shotcrete, full flow, frictional loss, pipeline transport, positive displacment pump

Jan 1, 2006

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

This paper pays tribute to the pioneers in geomechanics, and addresses some of the most pressing issues of our time related to deep mining, and how to mitigate these issues. Solutions developed by our predecessors seem to have reached their limits as mines continue to go deeper. The International Society for Rock Mechanics (ISRM) guidelines for rock mass characterization for excavation design also require re-thinking to reflect current knowledge and experience. Thus, a whole new approach is urgently required to increase mine safety and productivity. The paper will draw on the challenges and experiences in medicine and science that have been overcome through genuine collaboration, advances in technology, and impressive funding, which can be adopted to provide solutions to contemporary geomechanics challenges for increased safety and productivity as mines continue to go deeper.

Jan 1, 2014

By S. Sarac

In this study, graphical and mathematical methods used to determine operating points in single or multiple fan ventilation systems are summarized. The problem is mathematically formulized for parallel connected fans in which analytical solutions are not possible. For n number of parallel connected fans, a non-linear equation system that consists of n number of non-linear equation sis derived. The Newton-Raphson method, which is a numerical analysis method, is adapted to solve this non-linear equation system and the solution steps are given as an algorithm. A computer program based on this algorithm is written and its applicability is proved.

Jan 1, 2000

By K. M. Li, Y. D. Zhang

The selection of stripping dragline is a complicated problem. Several factors, such as the deposit buried conditions, the demand of mine production rate, cast blasting result, the mining/stripping operation method and parameters, etc. may comprehensively influence the optimal selection of technical specifications of the dragline. Under these circumstances, the basic thinking and procedures for dragline selection are put forward as follows. •Step 1—Initially estimate the dragline annual stripping rate and stripping bench height according to the annual coal production rate and advancing speed of mining front. Then the feasible alternatives of dragline sizes can be calculated and selected from the existing dragline series. •Step 2—A computer simulation model is developed to simulate the dragline stripping operation, to obtain a series of working face parameters, then to select the best dragline alternative. This step can be interactively iterated until the satisfactory results are obtained. •Step 3— Sensitivity analysis can be done with the systems simulation model by changing the stripping bench parameters, e.g. stripping bench height and cut width, etc. to verify and modify the selection results if necessary. The mathematical model for dragline stripping simulation has been set up. The flowchart of the model is shown. A case study for a large surface coal mine with annual production rate of 16 Mt/a is followed. The dragline bucket capacity and operation radius, stripping bench height and cut width as well as other parameters are comprehensively optimized and selected. Keywords: Open cast, dragline, specification, selection, cast blasting

Jan 1, 2003

The current methodology to design stope support systems in South African gold and platinum mines is based upon the tributary area concept. The discontinuous nature of the hangingwall rock is not adequately addressed, and mechanisms leading to rock mass failures between adjacent support units are poorly understood. The work reported here aims to formulate a basis for quantifying support mechanisms and gain insights into the influence of rock discontinuities on stable hangingwall spans. Numerical models are used to qualitatively investigate the stress transfer from the support units to the discontinuous hangingwall. Stable hangingwall spans are quantified by considering two failure mechanisms, namely (i) beam buckling, and (ii) shear failure due to slip at the abutments. The output of the proposed design methodology is appropriate site specific support spacing, based on discontinuity spacing and orientation. The method is particularly suited to mines at intermediate and great depth, where typically the hangingwall is highly discontinuous due to face parallel mining induced fractures. Results of parametric studies show that with increasing in situ compressive hangingwall stress, beam thickness and friction angle, hangingwall stability is increased, leading to wider stable hangingwall spans between adjacent support units.

Jan 1, 2000