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By R. Strydom, J. H. Selby, J. Slabbert, W. Enslin

Zircon is a naturally occurring silicate of zirconium, which is used in large quantities (~1 million tonnes per annum) for its refractory properties and its extreme chemical inertness. All zircons contain uranium and thorium bound into the crystal lattice, generally at levels up to 500 ppm of uranium plus thorium. This paper focuses on one aspect of the zircon industry—the ability to safely transport large quantities of zircon sand. Currently zircon is not classified as a radioactive material for transport purposes. However, this is because of a factor used in the exemption clauses of the IAEA code on safe transport of radioactive materials. The objective of this study was to determine the validity of this factor, and was submitted as part of an IAEA Coordinated Research Project (CRP). The study is based primarily on measured rather than modelled data and covers the transport of large quantities of zircon from producers in South Africa to customers in Europe. Both occupational exposure of workers and exposure of members of the public have been considered. The transport routes studied cover rail, road, ocean-going ship and inland barge transport of unpackaged bulk products. The study showed that the most exposed member of the public would receive 10µSv/annum,while the most exposed worker would receive 144µSv/annum of exposure. It is concluded that these levels are well below all regulatory limits for such activities involving naturally occurring materials. The study also showed that normal operational exposures are higher than those in accident scenarios, a feature which does not occur with higher activity materials. It is further concluded that the study validates the use of the factor of 10 in TS-R-1, as applied to zircon sand. Additionally it is also concluded that the exemption currently applied to the transportation of bulk zircon sand is valid.

Jan 1, 2003

By M. H. Moys

I had the good fortune to attend the above Conference which was held in Kanpur, India, on 11-15 December, 1995. The Conference was held in honour of Professor P.C. Kapur of the Indian Institute of Technology in Kanpur. Professor Kapur was one of the early students of legendary teacher and researcher of mineral beneficiation, Professor Doug Fuerstenau of the Department of Materials Science and Engineering at the University of California at Berkeley. I have attended my fair share of international conferences and this one certainly rated at the top of the list on several counts. With an open-hearted hospitality which one might almost take for granted once you have spent some time in India, the organizers of the Conference looked after every need of their guests, including breakfast and transport to and from the conference centre, wonderful traditional lunches and dinners and outstanding entertainment in the evenings. The papers were generally of a high standard, and debate flowed enthusiastically and freely. Several international guests delivered seminal papers in their fields as discussed below.

Jan 1, 1996

By P. Valicek, M. Farren, R. G. B. Pickering, G. Harrison, P. van Dorssen, W. Joubert, H. J. van Rensburg

Introduction In South African metalliferous mines, stoping operations are largely confined to narrow, tabular orebodies making mechanization extremely difficult. Limited flexibility in terms of stope width has necessitated drilling by means of hand held, pneumatic rock drills at most of our operations. As the largest producer of platinum in the world, we drill in excess of forty million stope blast holes per annum. Cleaning of the broken ore is also done by conventional means—utilizing scrapers and scraper winches. Conventional methods such as these carry high costs in terms of risk exposure as well as labour intensity. The purpose of this paper is to describe the development of a long hole stoping system suitable for the narrow platinum reefs. The new system had to be substantially safer and more cost effective than conventional mining. We selected a site that was conducive to mechanized mining and set out the parameters that we considered would meet our requirements. We then conducted a feasibility study to evaluate the conceptualized long hole stoping system in terms of specific goals. An analysis of the proposed system identified the Key Performance Indicators (KPIs). One of the most critical goals was to be able to create a man-freestope. This would mitigate the safety risk associated with normal stoping operations, as well as the inefficiency cost previously referred to. Other challenges included setting targets for long hole accuracy, stoping width reduction and specific blasting system performance for long hole stoping. We also modelled a critical span that we considered to be inherently safe and to ensure hangingwall stability, throw-blastcleaning and overall system productivity. Anglo Platinum Research and Development and Sandvik Tamrock entered into an agreement for the supply of a specialized long hole-drilling machine. The system was implemented and tested by the mine with the support of the other participants. The results achieved met our expectations. It was demonstrated that with this method of mining it is possible to have a man-free/support-free stope face and to achieve a reduction in shaft head cost per ton whilst reducing dilution. Key performance indicators assessed during the trial •Safety targets •Mining layout •Drill rig •Production targets •Support requirement •Explosives requirement •Services requirement •Ore removal and cleaning requirement •Training requirement Safety targets All persons involved with the project had to adhere to the mine’s safety programme including the zero-tolerance campaign, and were required to report all hazards observed immediately. Mine personnel and Tamrock carried out a full risk assessment on the drill rig before transporting underground. A further risk assessment was carried out when the machine was in position underground. Mining layout See Figure 1 and Figure 2 for a detailed description. Drill rig The drill rig was a combination of a Secoma P-Low LC 10long hole feed and an Axera low profile carrier. The choice of this equipment was made through consultation with Tamrock Sandvik. All relevant design perimeters of the area to be mined were taken into consideration. Production targets

Sep 1, 2001

By R. C. M. Minnitt, W. Dr. Assibey-Bonsu, F. A. Camisani-Calzolari

Born in Bothaville (OFS) on the 26th August 1919, Daniel G. Krige grew up in Krugersdorp on the West Rand. Hematriculated from Monument High School in Krugersdorpin 1934 at the age of 15 and graduated with a B.Sc. (Eng.)degree in mining engineering from the University of the Witwatersrand at the end of 1938 (age 19). In 1938 he joined Anglo Transvaal where he worked on a number of gold mines until 1943, gaining a wide range of valuable practical experience in surveying, sampling and ore valuation. He then joined the Government Mining Engineer’s Department where he worked for 8 years during which time he participated in the uranium negotiations with the British and American authorities and designed the uranium pricing formula for the contracts which led to the establishment of South Africa's profitable uranium industry in the early 1950s. During the same period he began his pioneering work in the application of mathematical statistics to the valuation of new gold mines using a limited number of boreholes and of ore reserves for existing mines. His early papers in the application of mathematical statistics, some republished in French, created world-wide interest that led to the development of the science and concepts that surround the spatial evaluation of mineral resources and reserves known as geostatistics. This technique has contributed to improved ore evaluation techniques as well as the reduction of the financial risks associated with investment in mining enterprises. Furthermore, it led to the recognition of his contributions to the evaluations of mineral deposits through the coining of the term ‘kriging’ that is used to describe a spatial mineral evaluation process known and practised in international mining circles. He continued his work in geostatistics throughout his career as Group Financial Engineer of the Anglovaal Group until his retirement in1981 and afterwards for ten years as Professor of Mineral Economics at the Witwatersrand University. He is still active as a consultant and is a registered Professional Engineer. He has published some 90 technical papers both locally and overseas, some in Russia, and has lectured and participated in international congresses in many countries. His contributions were recognized by the Witwatersrand University through the award of the D.Sc. (Eng.) degree in1963, by three honorary degrees (from the universities of Pretoria, UNISA and Moscow State Mining University), by many awards from the South African Institute of Mining and Metallurgy, the International Association for Mathematical Geology, Die Suid Afrikaanse Akademie vir Wetenskap en Kuns, the SME of the American Institute of Mining Engineers, the International APCOM Council in1999, the University of Antofagasta in Chile, and by the South African President (Order for Meritorious Service, Class 1, Gold). He has served on various Government committees, notably that for State Aid for gold mines (1967/8) and designed the State Aid formula which enabled many mines to survive a period of low gold prices; also various taxation committees, and the mining mission to Iran in 1974. He is a fellow and/or honorary life member of various technical societies locally and overseas, including the Royal Society of South Africa. During the period in the Government service he also handled several of the post-war lease applications in the Free State and Klerksdorp goldfields. The fact that decisions on new gold mines of critical importance to the State and the economy as a whole, were being taken on a limited number of drillholes without any scientific analysis of the risks of failure, stimulated him to start basic research into ore evaluation. His approach was based on the application of Mathematical Statistics to these problems, an approach of which very little was known world-wide at that stage but which had already been initiated in South Africa by Sichel via the lognormal frequency distribution model. In Krige's 1951 paper published in the Journal of the Chemical, Metallurgical and Mining Society of South Africa he covered the statistical explanation of the conditional biases in ore block valuations and stimulated the use by several gold mines of regression corrections for routine ore reserve valuations, a technique which, in effect, was the first use on an elementary basis of what is now known as kriging. His 1952 paper introduced, inter alia the basic geostatistical concepts of ‘support’, ‘spatial structure’,’ selective mining units’ and ‘grade-tonnage curves’. His 1951 paper was based on his M.Sc. (Eng.) thesis submitted in the Department of Mining Engineering to the University of the Witwatersrand, and expounded his pioneering work in geostatistics in more detail. His early research papers that had stimulated interest in several mining circles overseas, were republished in French in1955, resulting in a major research effort by French mining engineers in this field. This, in turn, led to the establishment of the now world-renowned French school of ore evaluation in Fontainebleau, Le Centre de Geostatistique de l’École des Mines de Paris. As the Group’s Financial Engineer at the Anglovaal Head Office until his retirement in 1981, he was responsible for

Jan 1, 2003

By A. K. Biswas

Reviewer: R. H. Eric This edition is organized in twenty-three chapters, and contains exactly 500 pages including three appendices and an index. The first and second editions were published in 1976 and 1980 respectively, and both contained nineteen chapters. The second edition brought the operating data and process descriptions up to date. The third edition covers comprehensively the changes that have taken place in the primary copper industry over the past two decades. For example, reverberatory furnaces now make up only a third of the major primary smelting furnaces, compared with about three-quarters in the 1970s. Control of air and water pollution and recycling are given much more emphasis, along with novel and emerging technologies.

Jan 1, 1995

By R. P. H. Willis, A. G. du Plessis, R. B. Wilson

This paper reviews issues to be considered in choosing primary access and transportation options for platinum and other mines. It proposes appropriate criteria and a methodology for deciding on the optimum primary access option for any particular orebody. Also included are generic parameters that can be used to facilitate the process of choosing the optimal access option.

Jan 1, 2004

A wide range of drill holes and process streams are sampled for resource estimation, grade control and contractual purposes in the minerals industry. However, despite the availability of training courses, conferences and both national and international standards on correct sampling practices, it is still surprising how often little attention is given to ensuring that representative samples are collected for analysis. The reason for this is that the responsibility for sampling is often entrusted to personnel who do not appreciate the significance and importance of sampling, with cost being the main driving force rather than whether the sample is representative of the material from which it was extracted. This seriously undermines the precision and accuracy of the analyses subsequently generated and can render the analysis process a total waste of time and money and expose mining companies to serious, potential, financial losses. Company management needs to reverse this situation and ensure that sampling is given the attention it deserves to generate representative samples for analysis.

Jan 1, 2009

Despite the media's use of the mining industry as a whipping boy over its perceived attitude towards the environment, the facts remain that the only legislated requirement in the SA Statute Books for any form of environmental impact-assessment prior to development is to be found in the Minerals Act in the form of an EMPR. Not only is our industry complying with this requirement, but moves are afoot to set up environmental management systems for existing operations in preparation for seeking accreditation under ISO 14001 when published towards the end of this year. On how broad a front are we advancing? ? Is the industry equipped to handle these challenges? ? Does it have the determination to overcome its problems? ? Do we realise that failure may mean the loss of markets overseas to competitors who can meet the international standards? ? Where are the shortcomings and when must our efforts be focussed?

Jan 1, 1996

By I. J. Kotzé, R. T. Jones

Conventional PGM matte smelting requires the presence of a certain quantity of base metal sulphides in order to collect the platinum group metals in a molten sulphidic matte phase in the furnace. Furthermore, the quantity of chromium oxide in the feed materials is controlled in order to avoid the build-up of high-melting chromite spinels in the furnace. Mintek has developed a process for smelting difficult PGM-containing feed materials that contain low amounts of sulphur and/or high amounts of chromium oxide. A DC arc furnace is used to provide the appropriate conditions to generate an iron alloy that collects PGMs very effectively, leaving extremely low residual quantities of PGMs in the slag. Various feed materials have been treated successfully in furnace campaigns running at power levels up to 1.5 MW. The longest of these campaigns was run continuously for more than four months, treating more than two thousand tons of materials such as low-grade concentrates, revert tailings, and converter slag. The campaigns demonstrated the robustness and versatility of the process, and proved that it is possible to sustainably produce a PGM-containing alloy and discardable slags containing an average of less than 1.4 g/t of PGMs over the entire campaign. Keywords: DC arc, smelting, furnace, platinum, PGM, revert tailings, converter slag, ConRoast

Jan 1, 2004

By C. J. Badenhorst

The primary focus of management today is safety, or preventing negative, generally irreversible, events of acute duration. The outcomes of safety-related events are usually visible and can evoke strong emotions if the results are severe. Experts now see that occupational illness and disease also result in significant emotional and financial toll to workers, their families and communities, and to their employers. Effective health and safety management must include acknowledging the importance of occupational health hazards and the proportionate application of resources to address those issues. Improvement in workplace conditions and decrease or elimination of illness and disability are due to actions within the workplace and result from the implementation of risk prevention and control measures. However, success may only be visible months or years later and may require interventions that have to be maintained over prolonged periods. This demands continuous, co-ordinated effort to ensure sustainability of diverse occupational health programmes and the relevant management systems. Too often occupational health is not seen as being part of the general management of business, but rather the function of a medical practitioner somewhere off site in a clinic. Integration of occupational health management systems with other management systems within an organization is essential for its success.

Jan 1, 2004

By Raphael Banda

1 Initiating Systems ? a definition An initiation system is a combination of explosive devices and component accessories specifically designed to convey a signal and initiate an explosive charge from a safe distance. In the use of explosives, the initiating system performs the functions of transmission and control of the firing signal to each explosive charge. As functional groups, initiating systems may be considered as: Starters Those which provide the initial signal to start the blasting process. Surface systems Products which provide transmission of the starter signal and delay timing (if any) across the surface of the blast outside the blast hole. In-hole systems Products which provide the signal transmission, delay timing (if any) and the initial explosives energy in the blast hole.1 2 Different types of Initiating Systems The initiation systems commonly used in Sub Saharan Africa are: ? Detonating cord and detonating relay systems ? Capped fuse and igniter cord systems ? Shock tube non electric systems ? Electric systems ? Electronic detonators 3 Overview of Electronic Delay Detonator Technology Conventional detonators use pyrotechnic delay elements and the variation of the actual delay periods is at best approximately 1% the nominal delay. The lack of guaranteed precision common to all pyrotechnic systems enhances the likelihood of negative environmental blasting effects.3 For example, take a 500 ms in hole delay. In conventional detonators this means that 95 % of shots fire within 10 ms of the mean. i.e. a window of 20 ms. Taking a fixed interval between shots of 25 ms, with a range of ± 3 ms, a very ragged firing pattern could be expected which in practice would result in non uniform fragmentation.

Jan 1, 2005

By G. P. Dyke

With the removal of the majority of the shallow mineral reserves there has been an increase in the mining depths in the South African mining industry. This has, in turn, changed the industry?s and stakeholders? perceptions of risk associated with mining-induced instability. In recent years the increased mining depth, particularly in open pits, has led to an increase in pit slope failures, which has highlighted the need for appropriate and effective pit slope management programmes. Such a programme comprises many facets, including mine hazard plans, regular slope inspections, cleaning of interim and final pit faces, blasting practices, histories of failures, pit depressurization, stormwater control and evacuation procedures. However, it is arguably in the field of slope monitoring that the most significant strides have been made in terms of new technologies and best practice in open pit mining geotechnics, with the introduction of technologies such as laser scanners and slope stability radar. This paper seeks to illustrate the operational benefits associated with the implementation of new technologies into open pit mining, using AngloGold Ashanti?s Geita Gold Mine in Tanzania as an example.

Jan 1, 2009

By A. Dienenthal

"The casthouse floor has always been one of the most dangerous working places on a blast furnace or a ferro-alloy/nonferrous furnace. Apart from working in an atmosphere including toxic gases, fumes, and dust, the workers have to perform hard and heavy manual work close to runners and ladles filled with hot liquid metal and slag.Before the invention and installation of tapping equipment the tap-holes were opened and closed manually. Opening was done by means of steel bars and sledgehammers, whereas the tap-hole was closed by repeatedly ramming small amounts of clay or refractory material into the tap-hole, again with the help of long, heavy bars. In addition, on blast furnaces the blast had to be stopped, since it was impossible to close the tap-hole properly against the blast furnace pressure. This stoppage of the blast resulted in regular losses of production. Around 1900 a major change in technology occurred. Samuel W. Vaughen, superintendent of the blast furnace department of the Cambria Iron company at Johnstown, Pennsylvania (USA), invented the first clay gun in 1895 (Wiley, 1896) (Figure 1)."

Jan 1, 2014

By C. M. G. Wortley, N. Randolph, I. Ralston, R. D. Beck

The ?AMIRA Metal Accounting Project? had its origin in a workshop held in Cape Town on 1 August 2001, with the title ?Challenges in Metal Accounting and Information Management?, which was organised by the Western Cape Branch of the South African Institute of Mining and Metallurgy. This workshop identified the lack of an accepted set of standard procedures for metallurgical accounting as an industry-wide problem. Discussions which followed this workshop led to the initiation of the AMIRA Project P754, ?Improving Metal Accounting?, in 2003. The primary objective of the project was to provide tools for improving the auditability and transparency of metal accounting from mine to product and to facilitate good corporate governance. The planned deliverables of the project were a series of research projects into aspects of metal balancing in different types of metallurgical operations, a Code of Practice on Metal Accounting, and a textbook on the subject which could serve as a guide for metal accounting practitioners and students studying the topic. An additional planned deliverable was the provision of a new variety of professional experts in metal accounting, through successful completion of the research projects. Researchers were engaged at the Universities of Cape Town, Queensland and Stellenbosch and the project was sponsored by five mining companies, including three of the largest global mining groups. Research Program Eight research projects were undertaken as part of the P754 project and these are described briefly here to indicate the scope of the project. University of Cape Town ?Development of a methodology for measurement network design for metallurgical accounting at Namakwa Sands?. This project was based on the Namakwa Sands Separation Plant, with a data rich environment, and involved the investigation of measurement network design through the use of heuristics and the analysis of complex processing circuits. An industry-wide survey of current practice to facilitate the development of an expert system for plant accounting measurements was carried out. ?Metallurgical accounting design at the Waterval UG-2 Concentrator?. The objective of this project is to develop a model for predicting metal recoveries from the different components of a blended ore feed to a plant. ?Optimal measurement network design for metallurgical accounting at Zincor?. This project provided a hydrometallurgical test case for the design and evaluation of a semi-automated optimal measurement network. University of Queensland ?Quantifying the relationship between mine and mill?. This project involved a case study at North Parkes Mine, in which copper and gold ore is tracked from the pit source to the product, as well as a stockpile modelling study. University of Stellenbosch

Jan 1, 2007

By A. W. Cramb

A three-day symposium on the production of clean steel organized by The South African Institute of Mining and Metallurgy, was held in September 1995 at Vanderbijlpark. It was attended by 151 delegates, who represented the whole of the steel industry in South Africa: Iscor Works, Saldanha Steel, Columbus Stainless, Highveld Steel & Vanadium, Iscor Research & Development, University of Pretoria, and Technikon Witwatersrand, as well as the users of steel products were represented. Professor Allan Cramb held the delegates attention with well-presented research and practical information. He obtained excellent interaction with the delegates by responding in depth to the questions put to him during the Symposium. In summary, he emphasized the following aspects of the elimination of defects during the processing of steel in continuously cast materials.

Jan 1, 1996

By C. Cunningham

The process of initiating opencast blasts through long cables is onerous. An obvious alternative is to replace these with radio controlled firing apparatus. Such devices appear from time to time and with the advance of telecommunications, more are likely to appear. However, there are two crucial and seemingly intractable obstacles to overcome: firstly, the problem of malfunction of the system, which can either fire prematurely or go into a state of suspense in which it is unknown whether firing might unexpectedly occur, and secondly, the problem of terrorism, as such a system could provide the capability for an off the shelf remote bomb. The issues of accessibility and electronic reliability when linked to explosives in a mining environment have to be demonstrated to be adequately covered before serious consideration should be given to these systems, up to now largely confined to military applications.

Jan 1, 2003

By F. W. Petersen

The Conference Minerals & Materials '96 was held in Somerset West, South Africa, from 31st July to 2nd August, 1996. It was organized by the Universities of Stellenbosch and Cape Town, the Cape Technikon, and the Western Cape Branch of The South African institute of Mining and Metallurgy (SAIMM). The three-day Conference was attended by 180 delegates, representing countries such as Australia, South Africa, United Kingdom, Finland, Sweden, Germany, Poland, Zambia, and Zimbabwe. The programme and associated exhibition were well organized, and each of the delegates received two volumes of proceedings containing the 77 papers presented at the Conference.

Jan 1, 1996

By J. R. L. Read, A. N. Ogden

This paper describes mining industry funded research that is being undertaken to address the critical gaps and uncertainties in our knowledge so that we can develop new approaches and create more effective ways for predicting the reliability of rock slopes in large open pit mines. It is envisaged that this research will not only lead to more effective pit slope design but further reduce the potential for unforseen geotechnical risks by enabling the geotechnician to communicate the risks more effectively with management and to optimise site specific control measures. To achieve this, several research tasks are in hand. The first is to accurately represent the structured rock mass with a 3D computer model (Siromodel) that creates polyhedral blocks from structural distribution data characterised by position, orientation and persistence. Siromodel is being coupled with particle flow and other numerical codes to evaluate how the structured rock mass deforms in the stress environment of an open pit and how a candidate failure surface may propagate through the dilating rock mass along the path of the least shear and/or tension resistance. A beta version of the Siromodel software has been distributed to 20 Sponsor mine sites for technical evaluation. The end state is to develop methods of analysis that characterise the reliability of a described candidate surface, and the probability of the candidate surface propagating to failure, recognising that the rock mass strength may well be defined in a different way than before.

Jan 1, 2006

Plurigaussian simulation allows constructing lithofacies or rock type models that reproduce the contacts between facies in accordance with the geologist?s interpretation. Its implementation requires inferring the local facies proportions, but the uncertainty in the true proportions is not accounted for. The simpler model with constant facies proportions may not yield realistic results, due to the possibility of obtaining facies at locations where it is geologically unlikely to find them. This article presents a variation of the plurigaussian model, in which the facies proportions are represented by random fields. The realizations can be made conditional to soft geological informati onto account for local changes in the facies proportions. The model is illustrated via a case study of a porphyry copper deposit where four Gaussian random fields are simulated conditionally to drill hole data and to constraints on the probability of finding a given facies at specific locations (control points) in the deposit. Then the first two fields are truncated using the random thresholds defined by the last two, generating a three-facies model. The proposed random proportion model proves to be simple to use and to account for spatial variations of the geological characteristics and for the uncertainty in the facies proportions. Keywords: categorical variable; lithofacies; truncated plurigaussian simulation; regionalized proportions

Jan 1, 2008

By L. Thomson

"The smelter at Sudbury Integrated Nickel Operations, located in Sudbury, Ontario, operates a single electric AC furnace. This furnace treats nickel sulphide concentrates produced by Glencore and third-party feeds and as such its performance is key to the company’s nickel supply chain. Currently the plant has two shutdowns per year in order to carry out significant repairs on matte tap-holes.Improved monitoring systems that enable better prediction of tap-hole wear have been a continued focus. The electric furnace is an essential piece of the smelter flow sheet requiring the need for planned tap-hole maintenance along with robust systems for management according to to this plan.The ability to meet our goal of zero harm is ensuring that safe practices are in place. Detailed procedures and cool-down practices have been implemented to ensure that required matte chemistry and temperature criteria can be met during the period leading into a shutdown for tapblock maintenance.A significant repair of the electric furnace will take place in 2015. During this rebuild, the sidewalls and matte endwall will be replaced. There is work underway to improve wall and matte end performance in an attempt to extend the time between rebuilds. This paper will review the approach taken towards this end."

Jan 1, 2014