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By W. K. Osae

A value assessment model which uses deal objectives, financial and non-financial indicators as a guide to assess value creation in mergers and acquisitions. The extent to which post- merger deal objectives are achieved and the potential benefits derived from mining deals that may not necessarily be financial of nature, but which are necessary to sustain and enhance future performance, were considered. The pre-merger and post-merger performances based on some financial indicators that reflect profitability for shareholders were also used. This value assessment model was used to assess four major deals that have occurred in the South African mining industry since 2003 as part of a postgraduate dissertation. In this paper, the Harmony and ARMgold merger is used as an example of how the model can be applied. The model?s relevance and applicability can also serve as a guideline in developing a framework or holistic guideline in assessing whether mining BEE deals in South Africa create value.

Jan 1, 2011

Contribution by J.S. Kuijpers* Kirsten's paper discusses the potential for seismic activity on faults in relation to depth, span, stope support, and discontinuity strength, and puts forward some explicit conclusions. Quoting from the author, the main conclusions are as follows, together with my comments. Author's reply The author gratefully acknowledges the contribution to his paper. It provides further elucidation to the very complex problem of quantifying the effects of mining-induced seismicity. The mechanical behaviour of rock under seismic excitation has been sadly neglected over the past twenty years, during which attention was almost exclusively focused on the study of the spatial location of seismic events. It is to be lamented that, on the eve of South Africa's movement to significantly greater depths of mining, so little quantities information is known about the mechanical effects of seismicity. It is a challenge at this stage to make up for this lapse in knowledge in the shortest possible time.

Jan 1, 1994

It is a great honour to officiate at the celebration of the centenary of the South African Institute of Mining and Metalurgy. Tonight's festivities bring back happy memories of my association with South Africa's mining industry during my tenure of office as Minister of Mineral and Energy Affairs. They also remind me of the illustrious personalities who have preceded me on this podium. The Pioneers They include Sir Percy Fitzpatrick, who spoke in 1909 on the eve of the Union, General Smuts, and, on many occasions during the 1920s and 1930, Jan H. Hofmeyr. The basic issues addressed by them continue to enjoy the Institute's attention today, namely the optimal and safe exploitation of our country's mineral resources and cost-effective extraction of minerals from their ores. Translated into the Institute's key objective it reads: To initiate and give effect to the means whereby the requirements for technology and scientific knowledge if the minerals and metals section if the South African economy is satisfied.

Jan 1, 1994

By A. O. Filmer

An account is given of a study on the non-oxidative dissolution in aqueous acidic solutions of nickel sulphides of different stoichiometric composition, in which a rotating ring-disc electrode was used. The rate of dissolution was found to depend on the potential of the sulphide and the nickel-to-sulphur stoichiometric ratio. A maximum rate for the dissolution of nickel from nickel sulphides containing an excess of nickel was recorded at potentials around -0,2 to -O,3V. The rate decreased markedly at more anodic potentials. For nickel-deficient nickel sulphides, the nonoxidative dissolution rate increased with a cathodic shift in potential. Under open-circuit conditions, a nickel sulphide of a composition approximating Ni ,S. reacted most rapidly. The dissolution rate was controlled by either a chemical or an electrochemical reaction at the electrode surface, had an activation energy of between 50 and 65 kJ.mol-1, and was independent of stirring speed.

Jan 1, 1980

By D. J. Bosman

The impoved densification of sludge from neutralized acid mine drainage. by D. J. BOSMAN, B.Sc., (Member) The paper describes an investigation aimed at finding a solution to the accumulation of acid mine drainage in the old workings at Coronation Collieries, Kromdraai. The problem involved the neutralization of the acid in the water, without the large volumes of sludge and the large amounts of dissolved solids that usually result from neutralization. Pilot-plant work on the site using a limeneutralization process developed at Bethlehem Steel Corporation (U.S.A.) showed this to be a feasible method. A sludge of 22 per cent density was obtained under optimum operating parameters. The amount of suspended solids in the overflow water was very high, but this does not give rise to concern because the full-scale plant at Kromdraai will practise secondary sedimentation by running the thickener overflow through large dams with a theoretical retention time of 25 days. An analysis of the theory underlying the process is also made.

Jan 4, 1974

By Nareetsile S., J. Kabwe

In the past few years Orapa and Letlhakane Mines have investigated various new technologies to enhance and improve production. The goal has been to improve productivity, reduce operating costs and make the mines more profitable The advent of Global Positioning Systems (GPS) in the early ’80s brought about the realization of this concept. Orapa and Letlhakane Mines started using GPS in 1999 and it is now used atLetlhakane mine for surveying, vehicle tracking and dispatching and for floor control system. Orapa Mine uses GPS in surveying, floor control and drill navigation. It will also be used for vehicle tracking and dispatching in mid-2001 following the installation of a fleet management and control system. The introduction of GPS at both Orapa and Letlhakane mines have improved productivity and reduced operating costs in the areas of drilling, topographic survey and floor control. In vehicle tracking and dispatching GPS has allowed for real-time information management for timeous decision-making which optimized fleet run time hours.

Sep 1, 2001

It is desirable to have a model, or method, for major project development, which will enable flexible modelling of separation circuits. This ability improves the understanding of circuits and how they should be operated, especially in a design phase, where various options are evaluated and decisions are made on the required number of stages and configuration. This paper describes existing gravity separation circuit modelling theory and concepts, as defined by Holland-Batt1 (separation window, separation efficiency and proportionality of efficiency). The crux of the paperis the application of numerical analysis to fit raw separation data by means of a modified Bézier-Spline. The paper proposes an alternative to the theory developed by Holland-Batt that provides more flexibility in the modelling of separation stages and curves, which include S-shaped curves. The paper proposes a solution to the challenge of continuously extrapolating data, and the first difficulty normally encountered, which is the fitting of an appropriate empirical formula to raw data.

Jan 1, 2007

By G. Gafner

The paper gives the reasons for the development of a gold alloy of 990 fineness with good colour, durability, and mechanical properties, and explains why titanium was chosen as the alloying metal. Methods are described for the alloy?s production, solutionizing, and age-hardening. Mechanical properties are given as a function of deformation, age-hardening time, and temperature for three different starting states, and these properties are compared with those of some standard 14 and 18 ct jewelery alloys and pure gold. The effects of various salts and fluxes on the composition of the alloy after heat treatment at 1150, 800, and 500°C are discussed. These indicate how alloy scrap can be refined to pure gold, and how solutionizing and agehardening can be conducted without the use of vacuum equipment. The results of wear tests indicate that the alloy is more durable than normal coinage and jewelery alloys. Tips are given on the grain refining, soldering, and casting of the alloy.

Jan 1, 1989

New Journals The following three journals may be of interest to readers: Fuel Processing Technology, Process Economics International, Speculations in Science and Technology, MM reports Report no. 2016 Analysis of the NIMROC reference samples for majorelements. Report no. 2018 Supergene aUeration of sulphide ores. II. The effect on the floatability of chalcopyrite, galena, and sphalerite. Report no. 2013 List of unrestricted NI M publications issued from 1966 to 1979. Report no. 2014 The determination by spark-source mass spectrometry, of chlorine and phosphorus in high-purity tungstic oxide. Report no. 2017 Vanadium-bearing titaniferous iron ores from the Rooiwater, Usushwana, Mambula, Kaffirskraal, and Trompsburg Igneous Complexes. Report no. 2022 The determination of thallium and indium in sulphide concentrates. Report no. 2023 Atomic-absorption spectrophotometry with hydride generation: an improved technique. Proceedings Proceedings of the Eleventh Commonwealth Mining and Metallurgical Congress, Hong Kong, 1978. London, Institution of Mining and Metallurgy, 1979. 800 pp. 35,00 or $U.S.77,00.

Jan 1, 1979

By M. Andersson, R. Elsrud

The quality and the production rate for the mining operations in the Garpenberg mine has been much improved due to a new system, that presents the latest exploratory and planning data for the driller at the moment he deploys the drill rig at the face. Other components in this improvement work are better planning procedure, large-scale production system with longer rounds and introduction of new drill rigs in the mine. The new Rig Control System (RCS) for the new series Atlas Copco Boomers L2C has made it possible to develop this system for production drilling in the Garpenberg mine. The ABC Regular has been extended with map navigation and drill plan generator. The driller will have the best estimate of the orebody in front of him and the best drill plan for that orebody. The customer’s specific system will also become a standard Atlas Copco product for the Boomer ABC drill rig family.

Sep 1, 2001

By H. S. Sichel

Statistical valuation of diamondiferous deposits By H. S. SICHEL, D.Sc The valuation of diamondiferous deposits depends on (i) the density distribution, (ii) the size distribution of stones and (iii) the selling price structure prevailing at a particular time. In the density distribution the stochastic variable is defined as the number of individual stones found per sample unit irrespective of the stone size. The density distribution is discrete and allows for barren sample units. As diamonds often occur in clusters, a Poisson mixture distribution is derived which is entirely new, as existing discrete distributions cannot represent the stone number frequencies found in nature. For the sizes of diamonds, which are measured by weight, a new compound logarithmic normal distribution is developed. Combination of (i), (il) and (iii) leads to a meaningful appraisal of diamondiferous ground expressed in monetary value per production unit of mining. Finally, confidence limits are calculated which allow for inferences from sampling to recovery.

By D. G. Krige

The problem of a realistic investment analysis for a new mining venture that sells its products on the international metal markets IS studied against the background factors, firstly, of different inflation rates between the countries hosting the mines and those. hosting the metal markets; and, secondly, of the changing pattern of currency exchange rates between such countries. The purchasing-power parity theory is used to establish a pattern of relationship between these two factors, and to develop a more logical approach to the long-term forecasting of metal prices in the currency of the country in which the mine is situated.

Jan 1, 1979

By E. J. Maunders

This paper describes briefly a computerised model of the South African electricity system which has been developed jointly by the Atomic Energy Board and the Electricity Supply Commission. The results of an analysis of this system have been subjected to a fairly extensive sensitivity analysis which reveals that up to the year 1990 between 680 and 700 million tons of coal will be required for electric power generation, together with between 7 000 and 10 000 tons of uranium. This result is fairly insensitive to data variations, but the prediction of a cumulative requirement up to the year 2000, of between 1 300 and 1 800 million tons of coal and 25000 to 70000 tons of uranium, proves to be very data-sensitive.

The visit which took place on the 18th February, 1972 was a departure in that the places visited had no direct connection with the work in which members of the Institute are normally engaged. It was refreshing and stimulating to see important and involved operations normally outside ones own trend of life and to have experts to speak about technical, financial and matters of general interest concerning their work, not forgetting their troubles and problems and how they overcame them. Carlton Centre The members of the Institute were received by Mr D. Appleton, Public Relations Officer of the Carlton Centre Limited, who introduced Mr L. R. M. Fee of W. Rhodes Harrison, Architect in charge of the project; Mr W. C. E. Skilton of Murray and Roberts, the Engineer in charge of the construction of the complex and Mr A. Home the Senior Operating Engineer of Carlton Centre Limited. Each of these gentlemen addressed the members giving short rundowns on the project with special reference to their particular sphere of the undertaking. A variety of particularly interesting statistics relating to the planning construction and the ultimate operation and maintenance of the complex was given. Mining engineers present had an opportunity to compare the problems encountered by them associated with depth to problems encountered by the civil engineer in the construction of a building rising to such an enormous height. To some of the members a sense of similarity of the labour problems encountered must have been recognised. After tea the visitors were divided into groups, each under the guidance of an official, and then visited the highest floor accessible and thereafter the 19th floor where the internal arrangements for airconditioning, lighting, plumbing, power supply and communication arrangements were explained. Thereafter a visit to one of the seven basements which houses all machinery required to serve this enormous complex enabled the visitors to see the standby power arrangements as well as the refrigeration plant. The visit finished in time to proceed to the Crest Hotel in Hillbrow for lunch. To our hosts for the visit to the Carlton Complex a special vote of thanks is recorded. Strydom Tower In the afternoon the party proceeded to the Strydom Tower where Mr Knight from the Public Works Department who was the Engineer in charge of the construction of the tower gave details on the construction and the extraordinary methods which had to be adopted to achieve the desired objectives and to overcome known as well as unforeseen difficulties. The comparatively short time taken to complete the project and the good safety record appeared to impress the visitors. The final phase of the visit was taken care of by Mr Bothma of Telecommunications Department of the Post Office, who gave an extremely interesting explanation of the telecommunication organization of the Post Office with particular reference to the part the Hillbrow Tower plays in the South African telecommunication system. Both gentlemen answered many questions willingly and interestingly. Following the explanatory talks the visitors were shown the technical equipment housed in the two top levels of the tower. Short explanatory talks gave members an insight into the workings of one of the most important aspects of modern life. Even to the amateur photographer opportunities existed to view and photograph the city from the highest available observation point. We are indebted to Mr Gouws, the Regional Director of the Post Office for granting permission to visit sections of the tower normally not accessible to the general public and to our hosts for the manner in which we were received and entertained on the explanation of the many interesting features of this important installation. In conclusion, the programme for the day can be classified as interesting, of exceptional educational value, and an opportunity to see something of the engineering skills put into two vast and ambitious undertakings and the results achieved.

By Mike Rogers

Platinum production in Southern Africa amounted to 80% of world production in 2005with a small increase from 5 117 000 ounces to 5 275 000 ounces. For the seventh consecutive year the platinum market is on course to record a moderate deficit in supply. This is reflected in the price increase from a trading range US$860 to US$880 in June 2005 to an excess of US$1 200 in September 2006. Southern Africa, with its extensive platinum reserves, will continue to be the dominant platinum producer and has a number of new mines in an advanced stage of planning. The slogan ?Platinum Surges Ahead? was selected to describe the exciting and vibrantnature of all aspects of platinum mining, beneficiation and marketing. This conference will cover these aspects from exploration and orebody delineation, through mine design, development and operation to mine closure; mineral beneficiation, marketing and compliance with the Mining Charter will also be subjects for discussion and debate. It is also anticipated that the issue of overall increases in productivity, through the introduction of technology, will demonstrate Southern Africa?s status as a premier mining district. It is my pleasure to welcome delegates from abroad and locally, on behalf of the SAIMM, to the Second International Platinum Conference ?Platinum Surges Ahead?. I trust that you will find the proceedings informative and value adding and will participate in the discussions and debate in order to obtain maximum benefit from the conference. I am sure that the post-conference tours will be interesting and of great benefit to participants. Finally, a big word of thanks to the members of the Organising Committee, the management and staff of the SAIMM, and to our willing sponsors, without all of whom this conference would not have been possible.

Jan 1, 2006

By G. Sánchez, S. Seiler, B. Klein, T. Cebeci, P. Bradshaw

The Decar Nickel District is a greenfield discovery by FPX Nickel Corp., of nickel mineralisation located in central British Columbia (BC), Canada. The Baptiste deposit is part of the Decar Nickel District and is a unique deposit containing a nickel-iron alloy mineral called awaruite, with over 2-billion tonnes of inferred resource grading 0.12% Davis Tube Recoverable (DTR) nickel. This deposit represents a significant nickel resource. Awaruite is a high density and ferromagnetic mineral, which could be recovered, along with magnetite that is also present in the samples, using magnetic separation. However, there is still a lack of understanding of the properties of the awaruite and its metallurgical response. This information is imperative for the set-up of the variables involved in its concentration. The aim of this paper is to show and discuss the effect of magnetic field strength for the recovery of nickel from Baptiste deposit samples. Magnetic separation at bench and pilot scale with different magnetic field strengths is evaluated as a concentration method for awaruite. Mineralogical information is provided to support the results and also to briefly assess the variability of DTR nickel within the deposit. The Baptiste deposit is unique and will benefit from a sound scientific understanding of the process solution as well as other ongoing work. If successful, the outcome will lead to the development of a mine. With greater than 2-billion tonnes of inferred resource, the mine would represent a significant new source of nickel globally. Keywords: Nickel ore processing, magnetic separation , awaruite, magnetite

Jan 1, 2020

By D. Lunt

This paper describes and sets in context the commercially proven uranium extraction processes. It also discusses some of the technologies that are currently being pursued with the aim of reducing costs and overcoming a number of technical issues that are faced by process designers and operators. In doing so, opportunities for the transfer of extraction technology from other industries/commodities are identified. The key processing areas that are examined include: ?The influence of mineralogy. The type of uranium mineralization and the nature of its association within a particular deposit will have a major impact on process route selection. Uranium minerals are classified according to their influence on extractive metallurgy. As the uranium price has risen in recent times, so opportunities are increasing for the recovery of uranium from less conventional resources such as phosphates and fossil fuels. ?The opportunities for employing techniques aimed at reducing the capital and operating costs of the overall process such as heap leach and beneficiation. Preconcentration by screening, gravity separation and radiometric sorting can potentially reduce the mass flow to the downstream leach and recovery plants. ?Purification or separation of uranium in carbonate systems. While it is possible to directly precipitate uranium from clarified leachate, the presence of impurities such as vanadium, molybdenum and others may dictate that ion exchange or selective precipitation is employed. Advances have been made in other industries in terms of improved ion exchange equipment aimed at reducing resin inventories and hence costs. ?Separation in acid leach systems. Earlier developments included the use of combined SX-IX systems (Eluex or Bufflex) and the introduction of continuous countercurrention exchange (CCIX). Column SX has found a ready application to uranium in view of the rapid extraction kinetics. With the renewed interest in uranium processing, efforts are being redirected towards further development of resin-in-pulp (RIP) as a means of driving down capital and operating costs. ?Extraction in a chloride environment. Australia and Namibia are desert countries where good quality water comes at a cost. However, both have access to saline water from either the ocean or subterranean aquifers. The issues associated with operating a uranium extraction operation in such environments is discussed. ?Extraction from less conventional sources. Recent price increases for U3O8 have resulted in a number of companies examining the recovery of uranium from sources such as fossil fuels and phosphate deposits. Both of these areas were examined in the 1970s and 1980s and a number of approaches were commercialized. The paper reviews the extraction options.

Jan 1, 2007

"Chairman: Mr W. S. GALLAGHERRapporteur: Professor A. M. STARFIELDPapers:Long-term mine production scheduling by G. C. S. BurneAn application of linear programming to investment analysis by A. ErlandssonOptimizing medium-term operational plans for a group of copper mines by M. Splaine, D. C. Atkinson, W. Davison and L. SmithThe simulation of underground stoping and transport operations in gold mining by F. H. Touwen and N. C. JoughinProduction planning is a subject that lies at the interface between the computing centre and mine management. Discus¬sion during this session was thus largely concerned, directly or indirectly, with communication between computing and mining personnel, and as such was relevant to the symposium as a whole.Mr A. Weiss set the tone of this discussion by referring to `user-orientated systems'. He congratulated Mr Burne in this regard, pointing out that his long-term production scheduling program, as a computer system, was similar in approach to the manual system it replaced, and was therefore easily understood by planning engineers. He asked whether the schedule engineer had his 'hands on' the system, to which Mr Burne replied that the engineer did in fact spend several days running alternative schemes through the computer. Mr Weiss commented on the advantage of having terminals on site for this sort of engineer-computer interaction. He also commented on the flexibility of Mr Burne's approach to scheduling and how preferable this was to a one-step optimization package. This was brought home by a question from Mr H. D. Small: Mr Burne's program sometimes found it necessary to temporarily halt an advancing face, and he asked whether the logic of the program could be altered to avoid this (e.g. by suitably slowing down the rate of face advance). Mr Burne replied that it was in fact easier for the planning engineer to sort this problem out manually. The way in which the computer results were presented made it particularly simple for the production engineer to see how to avoid or remedy a stopped face.On the technical side, both Mr Weiss and Mr H. M. Wells questioned Mr Burne on the handling of grade control by his program. From answers by Mr Burne and his colleague Mr K. H. Thomson it emerged that a spot-check on grade every now and then was all that was necessary at Mufulira, and that the idea of actual grade control was more a question of short-term than of long-term planning."

Jan 1, 2014

By J. D. Zhou, F. Yang, X. G. Bi

"In this investigation, the phosphorus distribution ratios in the CaF2 system and B2O3 system dephosphorization slags for high-phosphorus hot metal pretreatment were measured by an indirect method under laboratory conditions. Firstly, the phosphorus distribution ratio between liquid slag and solid iron was measured, and then the phosphorus distribution ratio between liquid slag and hot metal was calculated. Phosphorus capacity was calculated in terms of the composition and optical basicity of the slag. Dephosphorization slag was also studied by scanning electron microscopy, energy dispersive analysis, and X-ray diffraction analysis. The experimental results show that the phosphorus capacity of the B2O3 slag system is much greater than that of the CaF2 system. It is demonstrated thatB2O3 can completely replace CaF2 as fluxing agent for high-phosphorus hot metal pretreatment. With CaF2 as fluxing agent, the phosphorus capacity increases with increasing CaO content in the slag, but the phosphorus distribution ratio decreases. B2O3, when used as fluxing agent, can react with high melting point phases such as 2CaO·SiO2 and 3CaO·P2O5 in the slag to form new phases with low melting points such as 11CaO·B2O3.4SiO2, 2CaO·B2O3.SiO2, and Ca9.93(P5.84B0.16O24) (B0.67O1.79), thereby acting as a fluxing agent. When the ratio of w(B2O3)/w(CaO) is 0.16, the phosphorus distribution ratio reaches its maximum value, that is, the dephosphorization ability of the slag is at its maximum. IntroductionAs international iron ore prices continue to rise, the development of China's steel industry is facing a lot of pressure. Against this background, development and utilization of domestic high-phosphorus iron ore resources is particularly important. When highphosphorus iron ore is used in ironmaking, the phosphorus content in the hot metal can reach 0.35% or more, and the hot metal must be pretreated. For hot metal with 0.08–0.10% dissolved phosphorus, the traditional hot metal dephosphorization pretreatment technologies are relatively mature. However, when using these methods to dephosphorize hot metal containing 0.35% P or more, the amount of dephosphorization slag can reach 100–150 kg per ton of hot metal. Furthermore, the traditional dephosphorization methods require the addition of large amounts of CaF2 as fluxing agent, and this results in high fluoride levels in the dephosphorization slag. The fluorine in the slag can partially dissolve in water and thereby causes high fluoride concentration in the water and soil. Once the fluoride is absorbed by humans or animals, it can result in toxic effects on the central nervous system and myocardium. In addition, fluoride can accumulate in the environment, and thereby pose a health risk to animals and humans through the food chain (Li, 2007; Liu, Wang, and Dong, 2011, Diao, 2013). The objective of this research is to replace CaF2 with B2O3 as fluxing agent while achieving the expected goals of hot metal pretreatment."

Jan 1, 2016

By G. E. Blight

Several aspects of the behaviour and properties of backfills consisting of cemented cyclone underflow tailings are illustrated by means of examples, and guidelines are given on the optimization of the performance of cemented fills. The stretch characteristics of the geofabric used to contain freshly placed backfill are described, as well as the relationship between these characteristics and the forces acting on retaining barricades. The properties required to achieve a self-supporting, stable free face in cemented backfill are explored, and a graphic relationship between stable height and shear strength is presented and compared with that for uncemented (classified) tailings. After a description of the characteristics of Witwatersrand quartzite gold-tailings backfill and commonly used cements, the process of drainage and air entry into backfill is outlined. Following this, the early-age gain in strength and the shear-strength characteristics, as well as the compressibility characteristics of cemented backfill, are described. Two phenomena that are potentially damaging to cemented backfill are seismic effects (or blasting acceleration) and the closure that takes place during the curing of cement. Investigations show that neither of these phenomena is actually significantly deleterious to gold-tailings backfill: liquefaction does not Occur as a result of seismicity, and hydration of cemented fill is not significantly impeded by closure.

Jan 1, 1996