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By F. T. Cawood

This paper reviews the Mineral and Petroleum Resources Royalty Bill of 2006, identifies potential areas that require further consideration by the National Treasury and, where appropriate, offers alternatives. At its basic level a royalty regime consists of two elements: the base and the rate that must be applied to the base. Deciding on an acceptable royalty rate is a complex matter and can be done only after extensive analysis of all variables affecting the competitiveness of the regime. The proposed royalty rates are in the range of zero to five per cent and are based on sales revenue. It is argued that future investment patterns are more likely to be influenced by market cycles and commodity prices than policy events. Inevitably the current boom in the minerals sector will come to an end and the success of the proposed regime will be known only when profit margins are under pressure. Policy makers must therefore have the long run in mind when developing policies that affect the ability of industry to do business, without the need to renegotiate each time there is a change in the market. A long-run policy must be sufficiently flexible to allow for consistently fair sharing ratios and splitting of revenues between government and industry. Although broadly in line with international practice, the current version cannot be regarded as internationally competitive and efficient. In order for the royalty bill to become internationally competitive, promote beneficiation of mineral production and adequately compensate the State for the loss of a national resource, the National Treasury should heed the following main recommendations in this review: 1. Abandon the notion that each mineral product must have its own royalty rate; 2. Introduce an NSR type royalty that allows for value-addition costs to be deducted from the base; and 3. Provide for automatic relief through the use of a sliding-scale mechanism based on ability to pay, e.g. the X-Factor used in the gold mining tax formula.

Jan 1, 2007

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 K. G. Lomberg

The integration of various highly sophisticated IT applications has been implemented at Bafokeng Rasimone Platinum Mine, a new platinum mine in the Anglo Platinum Group. This system is required to assist with compiling the necessary geological and grade information together with safety, environmental, ventilation, rock engineering and logistical constraints, to allow the design of the appropriate mining layout, to schedule this design, provide the necessary output for technical review and costing as well as budgeting to allow medium- and long-term business planning. In addition the production management and short-term planning needs must be met. This includes the plotting of all underground and surface infrastructure and excavations, giving the necessary mining and best cut instructions, daily production management, ore reserve and grade management as well as assisting with budgetary management. In addition all safety, health, environment and risk assessment requirements and legal requirements have to be met. The system at Bafokeng Rasimone Platinum Mine has met these criteria. Keywords: Platinum, Bushveld Complex, Mine Planning, Production Management

Jan 1, 2003

By R. G. B. Pickering, H. H. Haase

CONTRIBUTION BY D. O'CONNOR Mechanical extraction of rock has been a goal sought after for some decades in the South African gold-mining industry. There are factors distinct from the mode of mechanical extraction that may have considerable influence on its prospects for extensive adoption; the rockburst factor is one of these. REPLY BY H.H. HAASE AND R.G.B PICKERING We agree with Professor O'Connor that, in conventional gold-mining operations, a disproportionate number of seismic events occur in the period immediately following a blast; rockburst activity follows the same pattern, and it has been calculated that, if the rockburst peak were spread evenly across the day, the rockburst exposure of stope workers would nearly double.

Jan 1, 1992

By D. G. Krige

D. G. Krige: The stimulating contributions from Messrs Cooke, Curtis, Martus, Johnston, Van Wyk, Van Rensburg and Wroth are appreciated by the author and provide clear evidence of the importance not only of the principle of assistance to gold mines, but also of its scope and form. In general all the arguments, raised by Messrs Cooke, Martus and Johnston in favour of extending the scope of the new assistance scheme can be accepted as sound.

By L. A. Vermeulen, D. D. Howat

A study was made of the performance of a rod mil operating without liter bars and with different arrangements of liter bars in the lining. . The results show that striking improvements in performance, increased throughput, and reduced consumption of liner metal and electrical energy can be obtained by a change in the geometry of the liter-bar arrangements within a mil. Rod mils of equal size fitted with the same arrangement of liter bars but operating at different speeds presented apparent anomalies in the relative consumption efficiency of electrical energy for the production of material smaller than 75 µ m. Marked savings in the consumption of liner metal were achieved by the use of an arrangement of alternating lines of higher and lower liter bars. A study of the relative performances of two large tube mils showed that the use of liter bars in one of the mils resulted in a marked reduction in the consumption of liner metal and electrical energy per ton of material smaller than 75 µ m in the product.

Jan 1, 1986

By A. J. Roets

Despite its growth over the years, necessitating ever¬larger office accommodation, the Gold Fields group changed its head office address in Johannesburg only twice in 94 years. The first move was at the turn of the century, from the then select suburb of Doornfontein to the corner of Fox and Simmonds Streets. The second move was in the thirties, from that address-now the Reserve Bank building-to the well-known address of 75 Fox Street. With the advent of the first mines of the West Wits Line by the end of the thirties, 75 Fox Street proved too small, and the eastern section of the Commissioner Street side of the present head office was added on. In the fifties, when space once more became a serious problem, the old Exploration building was purchased and demolished, and the present west wing on Commissioner Street was built on the site. In the early seventies, cramped conditions again made life difficult and, despite a reorganization of the interior layouts, the need for expansion remained critical. Eventually, the adjacent Hollard Place and parking area became available, and plans for an extended new building complex could he considered. The building project was

Jan 1, 1985

A knowledge of the steady-state mass and energy requirements of a particular process is essential to a determination of the economic feasibility of that process. A predictive simulation technique can be of great value in this respect. A versatile computer program based on a fundamental thermodynamic approach has been developed for the prediction of process requirements. The equilibrium composition of a multiphase system is determined by the technique of free energy minimization. Energy-balance calculations are performed using the appropriate thermodynamic data for the chemical species present in the composite materials used. All models for the process units under consideration are written in modular form, the output being calculated from the input and the specified operating conditions. The computer program is written in such a way that it can be used easily by anyone familiar with the processes involved, even though he may have no previous experience with a program of this type. The program is structured so as to facilitate the varying of one parameter without any alteration to the others, thus simplifying the investigation of the effects of any parameters considered to be important. The program has the advantage of being able to compare existing and new processes on the same basis, namely from the ores to the molten metal.

Jan 1, 1987

Notices TRANSPORTATION AND THE ENVIRO NMENT The 5th Quinquennial Convention of the S.A. Institution of Civil Engineers will take place at the Carlton Centre, Johannesburg, from 20th to 24th August, 1973. ENVIRONMENTAL ENGINEERING A conference on environmental engineering problems in industrialized and developing countries is to be held at the United Engineering Centre, New York, on 19th and 20th September, 1973. RABCEWICZ-COLLOQUY The Austrian Society for Geomechanics is to honour Professor Ladislaus V. Rabcewicz, on the occasion of his 80th birthday, with a meeting in Salzburg Congress Hall on 11th and 12th October, 1973. The themes of the four half-day sessions will be as follows. PYRO MET ALL URG ICAL EVENTS IN 1974 Diisseldorf is to be the venue for the following three events: International Iron and Steel Congress O.F.S. Branch Welkom THE MARCH GENERAL MEETING OF THE BRANCH WAS HELD IN THE ST. HELENA CLUB AT 8.00 P.M. ON TUESDAY, 6TH MARCH, 1973 O.F.S. Branch Welkom MINUTES OF A GENERAL MEETING HELD IN THE ST. HELENA CLUB ON WEDNESDAY, 16TH MAY, 1973, AT 8.00 P.M.

By J. H. Selby

The Southern African Institute of Mining and Metallurgy hosted the 6thInternational Heavy Minerals Conference at the Zulu Nyala Game Lodge near Hluhluwe in Zululand, during September 2007. This series of conferences has run for 10 years and has been held on three continents. The interest that has been shown in the conference over the years has demonstrated that the field of heavy minerals is a dynamic and profitable one. It is perhaps appropriate that the tenth conference was held in Zululand, South Africa, where it had its roots. The conference theme was ?back to basics?, and this implied revisiting many of the technologies that made this industry a great one. In doing so, we got a view of how those basic technologies have been put to new applications. There were 39papers accepted for the conference, covering all aspects of the industry. These were presented over a period of four days. This edition of the Conference Proceedings provides the reader with a permanent record of these papers. We hope this volume will join the other five, which this series of conferences has produced, and give a lasting record of the development of our industry.

Jan 1, 2007

By E. J. Walls, W. C. Joughin

"In selecting a suitable method to sink a vertical shaft for underground access, a number of constraints influence the ultimate decision of where and how to develop the shaft, not least among these being safety, development and construction time, and cost. Two additional considerations stand out: these being geotechnical conditions and technology, the latter taking into account existing underground access. Assuming a project for which an existing underground excavation is available, it is tempting to build a shaft sinking project from the outset based on the raiseboring method, which has the potential to be the safest, fastest, and least expensive method provided that geotechnical conditions permit.And therein lies the rub: regardless of project time or cost constraints, when it comes to raiseboring a long (say, greater than 500 m), large diameter (greater than 4.5 m) shaft, the rock mass conditions ultimately dictate what method of shaft sinking will be feasible. Over the course of several studies for a particular project, several geotechnical analyses were carried out specifically for the purpose of developing a shaft by raiseboring. Risk analysis and experience showed that where the rock mass conditions indicated an unacceptably high risk potential, an alternative method needed to be considered, even if this meant increasing both the time and financial requirements.In this paper we present an overview of geotechnical investigation practices for shaft sinking. Decisionmaking thresholds for raiseboring or other methods of shaft sinking are discussed, including probabilities of failure, empirical rock mass classification, basic wedge failure, and back-analysis of a failed case. The design of appropriate support, and analysis of relative safety benefits for various shaft sinking methods, falls outside the scope of this work, and will be presented in a separate paper.IntroductionThe potential for rock mass failure during shaft development and construction affects whether a project is completed safely, on time and on budget. During the course of several studies to establish ventilation shafts for an underground expansion project, geotechnical analyses of rock mass stability and failure potential were carried out. The investigations were guided by the method of McCracken and Stacey (1989) together with insights from Peck and associates (Peck, 2000; Peck and Lee, 2007, 2008; Peck, Coombes, and Lee, 2011)."

Apr 1, 2019

By S. Ramatsoma, D. N. C. Phillpotts, B. Whitehead

Changes in flotation performance have been correlated to changes in froth structure, velocity and stability. Literature has shown that when the aeration rate is varied for a specific float cell, the recovery of the valuable mineral reaches a peak which also coincides with a peak in the air recovery – a measure of froth stability. Peak air recovery optimisation methodology is a way to use direct readings of physical phenomena by froth cameras to optimise the metallurgical performance of a flotation plant. The aim of this paper is to show the transient nature of the peak air recovery value and the variety of conditions required to attain the peak air recovery on an industrial flotation plant with tight base-layer control of the feed and internal conditions. Industrial site tests that were conducted under controlled conditions showed different peak values at significantly different corresponding aeration rates during normal operation. The measured peak air recovery points corresponded to maximum PGM recovery during normal flotation, as expected. This dynamic nature of the peak air recovery point conditions has not previously been discussed in literature and indicates the need for online measuring equipment and informs the design of process control algorithms required to exploit the phenomenon for optimisation. Keywords: Froth flotation, flotation control, flotation optimisation, peak air recovery

Jan 1, 2020

By C. Mueller

Automation of mining operations is pushed by cost pressure and cyclical product prices. However, until now the different types of equipment were not able to communicate electronically with each other or with central computer systems. Therefore, the International Rock Excavation Data Exchange Standard (IREDES) was launched by major players in the industry. The task of this initiative is to define a ‘common electronic language’ for easy and standardized data exchange. As in other industries, this standard is expected to have significant impact on the use of automation in general and on the markets for third party components and software. The standard’s technical architecture is open and flexible for future applications. It consists of an ‘horizontal’ structure defining ‘Application Profiles’ for different types of data sets. An additional ‘vertical’ structure (‘Equipment Profiles’) implements equipment dependent definitions for each of the applicable Application Profiles. First profiles will be available for Drill Rigs. The standard bases on the XML language thus enabling easy data exchange with commercial databases. IREDES data sets may use storage media as well as networking infrastructures for information exchange. The IREDES work is carried out by the initiative members working jointly together in the IREDES work groups. It is open for participation of all interested organizations. First prototyping applications are expected to start during 2001, the first products may be available in the following year. Key words: Mine Automation; Machine Automation; Data Exchange; Rock Excavation; Standard; Remote Control; Teleoperation; Ethernet; TCP/IP; Internet Technology; Service; Quality Assurance; Control Centre;

Sep 1, 2001

By L. A. Vermeulen, D. D. Howat

New distribution functions are derived to describe the size distribution of grinding elements in ball mils. The formulations are based on the assumption that abrasive as well as impactive interactions occur during bal milling-an assumption that is supported by a large body of experimental evidence. It is shown that the functions can be used in the estimation of the magnitudes of abrasive and impactive components in the total rate of bal wear. The relative magnitudes of the wear components provide a basis for optimization of the chemical and metallurgical properties of the balls in a given milling situation. However, it is contended that these quantities are also useful indicators of the relative intensities of the abrasive and impactive interactions that are operative in the size reduction of mineral particles within ball mils. These quantities can be determined for any industrial ball mil, and their magnitudes provide practical guidelines for mil operation. The theory is used in an analysis of samples of ball charges from two industrial ball mils, and it is also applied to al the data on bal-size distributions found in the literature. The qualitative correlation between the calculated values of the wear components and the reported operating conditions is good for a variety of industrial ball mils, in conformity with the hypothesis that the relative magnitudes of the wear components are related to the milling conditions.

Jan 1, 1986

By E. Bakhtavar, R. Mikaeil, D. Khademi

"Fuzzy-weighted integer goal programming has been developed and used to select the most suitable site to construct a central processing plant for several adjacent small-scale dimension stone quarries, based on the most effective criteria. In the first step of mathematical modelling, the most important goals and decision variables were defined. Accordingly, an objective function was used in the model for minimizing the sum of undesired fuzzy-weighted deviations. Fuzzy weights were determined by a matrix of pairwise comparisons of various expert judgments in this field and the fuzzy geometric mean. The goal and systemic constraints were also modelled. The most suitable site for the construction of the plant was selected after solving the mathematical model in the ExcelR Solver add-in. The selected site had various advantages over the other sites, such as the shortest average distance to the quarries, the shortest distance to power access and workforce, and the lowest land price. IntroductionSelection of the most suitable site of a plant is one of the most important considerations when constructing an industrial project. A suitable site has a significant effect on a company's competitiveness in the market. Selecting a desirable location for constructing plants such as mineral processing facilities is an essential part of the economic planning that will enable a company to meet the needs of related upstream and downstream operations. These units are considered to be best built near the relevant mining sites because of technical difficulties, the cost of transporting minerals, and the traffic hazard caused by the movement of trucks transporting materials. Two main types of research using multiattribute decision-making models have been reported for selection of a processing plant site (Safari et al. 2010, 2012). In that research, the analytic hierarchy process (AHP) and fuzzy technique for order preference by similarity to ideal solution (TOPSIS) approach were applied to select the suitable locations for the mineral processing plants for phases 1 and 2 of Sangan iron ore mine."

Jan 1, 2017

By J. W. Neale

Mintek was a leading participant in the BioMinE project between 2004 and 2008. This project, which was funded in part by the European Commission, was aimed at the development of biotechnology for the minerals industry in Europe. Mintek?s research programme focused mainly on the development of integrated bioleach-based processes for the recovery of base metals from complex, low-grade sulphide concentrates. Specific European mineral resources were targeted and used in integrated piloting campaigns involving bioleaching, solution purification, and metals recovery. This paper describes the use of thermophilic bioleaching for the recovery of nickel and copper from a low-grade nickel-copper concentrate produced at the Aguablanca Mine in southern Spain. Currently, the Aguablanca Mine produces a bulk nickel-copper concentrate for sale to a smelter, and the proposition is to increase the profitability of the operation by the on-site production of metal or metal intermediate. Initially, bench-scale bioleach tests were conducted to determine the bioleach operating conditions. These tests included an evaluation of mesophilic, moderately thermophilic and thermophilic microorganisms. In order to achieve sufficiently high levels of both copper and nickel extraction, a thermophilic process was selected?this was necessary for leaching of the refractory chalcopyrite that occurs in this concentrate. Additional bench-scale test work was carried out to derive a conceptual process flowsheet for the solution purification and metals recovery circuit. The results of the bench-scale tests were used to design, construct and commission an integrated pilot plant, which was subsequently operated at Mintek for over seven months. During this time, the solution purification and metals recovery processes were optimized, and all recycle loops were closed. The final process flowsheet included the following unit operations: concentrate regrinding, thermophilic bioleaching at 70°C, primary iron removal using limestone, copper solvent extraction and electrowinning, secondary iron removal, nickel hydroxide precipitation using magnesia, and final solution purification using lime. Where applicable, process solutions were recycled to preserve water. The process design data derived from this pilot-plant campaign formed the basis for a conceptual engineering study for the developed process. In the study, mass and energy balances were derived, and a process flowsheet was developed and used as the basis for estimating the capital and operating costs of the process. This enabled a preliminary economic analysis of the process to be undertaken. The findings of this study are discussed.

Jan 1, 2009

Notices 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 RlOO 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. APPLICATION AND PRACTICAL OPERATION OF HYDROCYCLONES Dr H. F. Trawinski of Amberger Kaolinwerke, Hirschau, West Germany, gave a very interesting lecture on this subject to an audience of over one hundred, composed largely of members of the Institute, on 15th August, 1973, at the University of the Witwatersrand. ROTARY INTERNATIONAL Applications are invited before 15th March, 1974, for the following awards of The Rotary Foundation: Post-graduate Fellowships Under-graduate Scholarships Awards for Technical Training Awards for Teachers of the Handicapped. NIM REPORTS Report No. 1509 The instrumentation developed for electrochemical studies of the le(Whing of uranium dioxide. Report No. 1550 A fundamental study of the dissolution in (Wid solutions of uranium minerals from South African ores. Report No. 1552 The preparation and analysis of minerals for use as reference material.Progress report No. 2. Report No. 1556 The spectral analysis of solutions.2. The analysis of leach liquors, concentrates, slags, and residues. Report No. 1559 A cost assessment of the production of elemental sulphur by chlorination roasting. Report No. 1562 Application of a flotation model to an industrial plant

Jan 11, 1973

By J. P. Hoffman

In 1988 the Japan Iron and Steel Federation started a research-and-development programme known as DIOS (direct iron-ore smelting). Eight Japanese integrated steel producers and the Coal Mining Research Centre, subsidized by the Ministry of International Trade and Industry, are involved in the project. The aim of the programme is to have a 500 v/d pilot plant for the production of iron via an oxygen-coal in-bath smelting converter in operation by mid 1993. The three main components of the DIOS process are as follows: ?a fluidized bed for the pre-reduction of iron-ore fumes ?in-bath smelting reduction in a converter ?off-gas reforming by the addition of coal fines. The main drive is to provide a smelting process that is more energy-effective, using coal instead of coke and/or electricity. The advantages claimed include inter alia ?direct use of fine iron ore ?direct use of non-coking coals-low coal consumption ?low capital expenditure-replaces costly coke ovens, agglomeration plants, and the blast furnace ?economical production on mini-plant scale ?less of an impact on the environment. This concept of 'direct steel has been carried over to the production of stainless steel direct from the ores, again bypassing such energy-intensive units as the submerged-arc furnace for the production of ferrochromium. A number of Japanese companies have indicated a certain amount of success. Several interacting elements are recognized that could have a productivity-limiting aspect. The possibility of the direct production of stainless steel from chromite is discussed briefly with reference to the Highveld of the eastern Transvaal as a possible site for such a plant

Jan 1, 1992

By H. Rosenberg

Haldor Topsoe A/S has developed its WSA technology to meet the demand in the market for a simple and reliable process that converts sulphurous emissions from off-gasses into high-grade sulphuric acid. With more than 50 references in 25 countries, the WSA technology has proven its ability to generate acid at 98% concentration, efficiently and economically. The wet gas sulphuric acid (WSA) technology treats the furnace off-gas directly from upstream gas cleaning plants. No further drying is required, since the humidity present in the off-gas is used to hydrate the SO3generated in the converter and produce sulphuric acid. The heat generated during the oxidation, hydration and condensation processes is principally reused in the process to preheat the off-gas to the required temperature level, and also to generate high pressure superheated steam for process use. This advantage of steam production, coupled with lower water and power consumption requirements, is particularly important in the African production environment. Having fewer process components than conventional acid plants, the WSA technology is a simple and compact operation, which makes it easier to retrofit into an existing smelter plant. Further, the WSA technology simultaneously offers the possibility to treat multiple gas streams arising within the production facility due to superior flexibility in terms of SO2concentration and turndown ratio.

Jan 1, 2006

By D. Fourie

A brief history of channel sampling in South African gold mines is followed by a chronicle of different sampling events and sampling methods that used the traditional ?hammer and chisel? approach as well as diamond core extraction of the sample. The problems associated with each method of sample collection are documented and the use of a laser scanner to measure the exact volumes of sample material extracted from a correctly delimited sample site are considered. Areas where increment delimitation errors (IDEs), increment extraction errors (IEEs), increment weighting errors (IWEs), and increment preparation errors (IPEs) occur were investigated. A ?simulated chip sample model? is introduced and provides the basis for comparing the percentages of error introduced as a result of improper sampling. The heterogeneity experiment showed that reefs that are more homogenous tend have lower extraction errors than the more complex carbon-rich reefs, which may contribute to understanding the poor mine call factor on mines exploiting the latter types of reef. Keywords channel sampling, chip sampling, error, bias, modelling.

Jan 1, 2014