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By Arvi Parbo

I would like to use the occasion to reflect on how the world environment for the minerals industry is undergoing substantial change, and how this change may affect the industry. I have given my talk the title 'The Quest For Competitive Edge', because the net effect of the changes taking place is that competition is increasing. To set the scene, let us look back at the situation which has existed in our industry in the past.

Jan 1, 1993

By G. T. van Rooyen

Materials for Winding Plant Components By Prof. G. T. van Rooyen (ScD) (MIT). Materials for critical applications such as winding plant components are reviewed in terms of the basic requirements which have to be complied with. It is shown that tensile testing alone is not sufficient and that impact testing also is necessary if the incidence of brittle fracture is to be avoided. As a criterion it is suggested that the brittle transition temperature (B.T.T.) determined by impact testing should in all cases be well below the lowest anticipated service temperature. A number of steels were evaluated by impact testing and it is shown that a small ferrite grain size, obtained either by chemical means such as by the use of appropriate alloying elements in the steel or by means of a quenching heat treatment, is effective in attaining a Iow B.T.T. The speed of strain aging as well as the influence of strain aging on the B.T.T. was also evaluated. On the basis of the results obtained it is recommended that steels for critical applications must conform to an appropriate grade and class of steel according to BS 4360 specification. It is further recommended that such steels be exempted from the customary six-monthly heat treatment prescribed by the Mines and Work Act, Regulation 16,18.

A 36-year-old A-S-H pump, manufactured to designs dating back to 1936, was recently presented to the Gold Mine Museum by Envirotech. The pump, a B-frame three-piece rubber-lined Hydroseal unit, was supplied by Envirotech's predecessor company, Denver Machinery, and was installed by South Roodepoort Main Reef Areas Limited on 22nd March, 1948. Metals, materials, manufacturing The 37th Annual Conference of the Australasian Institute of Metals will be held in Ballarat (Australia) from 13th to 17th May, 1985. 1985is the Sesquicentennial year of Victoria, and for the first time the historic City of Ballarat has been chosen as the venue for an Australasian Institute of Metals congress. Steel rolling Conferences on steel rolling, sponsored by The Iron and Steel Institute of Japan (ISH), and supported by iron and steel institutes in many countries of the world, have been held since 1980. The first conference was held in Tokyo in 1980, sponsored by The Iron and Steel Institute of Japan.

Jan 1, 1984

The Centenary Luncheon for Past Presidents was held on Thursday, 24 March, 1994 at The President's Room at Gold Reef City, Johannesburg at 12:30. Herewith the proceedings that followed. Dr H. Scot-Russell It is with great pleasure that my fellow Office Bearers and I welcome you, our Past Presidents, to this luncheon to mark the centenary of the SAIMM. Today one hundred years ago, a group of professionals met and agreed to draw up the constitution and by-laws of a society later to be called an Institute. The Presidents of the Institute, of course, become its Past Presidents and help to guide its progress. A number of our sister institutes cannot wait for their Past Presidents to move of their councils, and cannot understand how we can give such free reign to ours! We believe it one of our strengths. The successful cooperation between our Past Presidents and ourselves is due to the personalities of these men. They attend meetings not to ensure that the status quo is maintained, but allow the current Office Bearers freedom to lead the Institute as they think fit. But they are always present to give sound advice, a helping hand, and support to the Institute in every way.

Jan 1, 1994

By W. J. Vlasblom, A. M. Talmon, A. J. Nobel

In initial laboratory tests with a travelling submerged jet on artificially prepared clay it was found that the cavity depth is dependent on the stagnation pressure of the jet and the undrained shear strength of the clay. In addition, it has been observed that the increase in cavity depth with jet pressure is stronger at higher jet pressures. It is assumed that this can be explained by cavitation of the jet at higher jet pressures. At cavitation a cone of bubbles is formed around the jet, which reduces the exchange of momentum between the jet and the surrounding water. This results in a higher jet velocity and a higher stagnation pressure at a specified distance from the nozzle exit. In literature, no relation between the jet pressure of a free submerged cavitating jet and stagnation pressures was found. Additional tests were carried out to determine this relationship. Because practical dredging occurs at relatively large water depths, these tests were performed in a pressure vessel at different pressure levels. It is concluded that the efficiency of a jet (defined as the stagnation pressure at a certain distance divided by the jet pressure), for stand-off-distances smaller than 45 times the nozzle diameter, increases significantly by cavitation in comparison to the non-cavitating situation. However, the jet pressure required for a fully developed cavitation cone increases strongly with water depth. At dredging depths of 20 m and more, the necessary jet pressures are higher than normally applied in dredging practice. Thus in spite of the importance of cavitation in laboratory tests at atmospheric pressure, in normal dredging practice cavitation is of less importance.

Jan 1, 2007

By P. G. Van Der Walt

This paper deals with the reticulation of deslimed tailings from surface to the stope face underground. Reference is made to the experience gained at the pilot plants operating on four of the gold mines administered by Gold Fields of South Africa, as well as at the full-scale system at East Driefontein which was commissioned recently. Mine-wide backfill systems are currently being installed on five other mines administered by Gold Fields. These six full-scale systems are capable of handling more than 270 000 tons of backfill solids per month. The type of reticulation system chosen, the selection of flowrates and the composition of the slurry, as well as the selection of the appropriate pipes and ancillary equipment are discussed. Both theoretical and practical aspects are taken into consideration. Other aspects covered include the design of underground storage dams and communication systems.

Jan 1, 1988

COUNCIL The following served on Council during the year under review: Office bearers: Prof D. D. Howat (President), Dr J. P. Hugo and P. W. J. van Rensburg (Vice-Presidents), V. C. Robinson (Immediate Past President) and D. G. Maxwell (Honorary Treasurer). Ordinary Members of Council: H. P. Carlisle, R. C. Espley-Jones, G. H. Grange, Dr D. I. Legge, W. W. Malan, Prof R. P. Plewman, Dr R. E. Robinson, Dr M. D. G. Salamon, L. W. P. van den Bosch and P. A. von Wielligh. Branch Chairmen: A. Bain (Witbank-Middelburg Branch), J. M. Meyer (O.F.S. Branch). Past Presidents serving on Council: R. J. Adamson, M. Barcza, H. Britten, H. E. Cross, J. K. E. Douglas, R. C. J. Goode, P. Lambooy, Prof J. de V. Lambrechts, Dr J. T. McIntyre, J. F. Reid and H. Simon (until March 1972). Ten Council meetings were held during the year with an average attendance of nineteen, and the standing committees held 27 meetings. FINANCE The annual accounts which are attached to this report show an excess of income over expenditure of R21 519. It is very gratifying to be able to report that Council's efforts to stop the depletion of our accumulated funds are meeting with success. The most important contributors to our surplus this year are symposia and colloquia, sales of publications, Company Affiliate subscriptions and the profit on the journal. While we do not expect continued profits from all these sources in the future we do feel that we are now in the process of accumulating a substantial financial foundation. This will give the Council the necessary confidence to initiate the new developments in the activities of the Institute which are now under consideration. The decision to create a new grade of membership, Company Affiliate, is dealt with elsewhere in this report. There has been a generous initial response from companies and this is the cornerstone of our improved financial expectations. The MacArthur Forrest Memorial Fund shows an excess of income over expenditure of R91 and the total fund was, therefore, increased by this amount to R4 502. The balance sheet shows that the market value of quoted shares and debentures increased during the year from R9 160 to RH 331, which is R2 134 in excess of the book value. Accumulated funds now amount to RH 529 compared with R23 010 a year ago. MEMBERSHIP Sixteen Fellows, twenty Members, six Graduates, nine Associates, twelve Students and twenty-four Company Affiliates were elected during the year. One Member and two Associates were reinstated. Twelve members were admitted to retired membership. Transfers: Member to Fellow, three. Graduate to Member, seven Associate to Fellow, one. Student to Member, one. Student to Graduate, four. Student to Fellow, one. Your Council records with deep regret the death during the year of the following: Dr A. J. Orenstein (Honorary Life Fellow), R. A. Cooper, R. J. Spargo, H. Simon and F. Meyer (Life Fellows), S. D. Loxton, W. P. Arnold, G. C. Needham, W. G. Pyne-Mercier, J. Innes and O. T. Wright (Fellows), E. P. Mennell and O. B. Prentis (Members), J. Brits (Associate). After careful consideration of all the implications it was decided during the year to create a new grade of membership to be known as Company Affiliate, in order that there might be a formal and permanent channel for companies to contribute to the important work of the Institute. As recorded above, 24 companies had joined by the end of the year and many further applications have been received since. We extend a hearty welcome to all our new members. A comparative statement of membership as at 30th June, 1972, and the end of the previous year is shown in the following tabulation:-

By P. Horrell, K. Rhodes, G. Harrison, J. Dean, D. Sammons, M. Stander

Anglo Platinum have perceived a need to increase the rate of reef development both for new mechanised stoping technology and on conventional new developing mines. The Research and Development Division of Anglo Platinum therefore initiated an experimental reef raise project with a tunnel boring machine (TBM) at Bafokeng Rasimone Platinum Mine (BRPM). The scope of the trial was for the boring of a reef raise 340 metres in length on the Merensky Reef. The boring phase of the trial took place over six months and the average rate of penetration of the TBM was 0,47 metres/hour. TBM utilisation was 22%. The TBM used in the trial was a Jarva MK6 manufactured in 1972 and its design with its backup system was not considered to be an ideal machine for reef development. However it was the intention of the trial to prove the concept of developing with a TBM on reef. In this respect the trial was unequivocally a success. There were many problems and long delays did occur during the boring phase. Nevertheless there is every confidence that a new TBM can be designed specifically for this type of work that will achieve high rates of advance up to (say) 400metres/month and with a more flexible steering system in order to negotiate reef changes. It can therefore be expected that TBMs will be used in the future for reef development on South African platinum mines.

Sep 1, 2001

By H. Xuchun, H. Nailian, L. Guoqing

With the accession to WTO and the establishment of Shanghai Gold Exchange, gold mines in China are facing more severe competition from both home and abroad. Supply Chain Management (SCM), a new management idea gradually accepted all over the world, provides the gold mines in China with a new management mode. In this thesis, under the guidance of SCM theory, based on the analyzing to the actualities of Jiaojia Gold Mine, the Jiaojia supply chain framework is constructed, the function system for Jiaojia SCM is configured, and function modules are described in detail. Keywords: Supply Chain Management, Gold mine, Informatization

Jan 1, 2003

By R. G. Koelmans

In 2001 Platinum overtook gold in foreign revenue earnings for South Africa. The export sales from platinum group metals amounted to R29.3 billion as opposed to gold export sales of R28.6billion1. Organizations must undertake new ventures to replace old, worn-out and obsolete assets with new ones. These assets could be a building, a new product or process, a new mine, or anything that can help the organization to achieve its objective. These ventures are projects by their nature. When a project is pronounced a success, the judgement is usually based on some factual evidence, although not every one uses the same data. From the literature, it is obvious that there is a lack of consensus and objectivity as to what constitutes a successful project. The purpose of this paper is to address the following questions: ?What constitutes a successful project? ? How does one measure project success? ?How can one work toward project success? This paper addresses the requirements for project success of three of the primary stakeholders of a project, namely the business or client, the employees as far as the project team is concerned, and the local community. Indicators are developed into a work breakdown structure (WBS)-like chart to demonstrate success indicators. These indices take cognisance of all the constituents required for project success. The indicators are further developed to take cognisance of the requirements of the local communities. These indices are then weighted to arrive at a total score for the respective stakeholders. Using these WBS models, the success and performance of a project can be evaluated. This score is considered an objective measure of project success. Projects are evaluated more consistently across different projects and the project manager is provided with a management tool that can assist him/her in ensuring greater project success. The shortcoming of this approach is that the weights of the different indices have been estimated at this stage. Research will have to be conducted to more accurately reflect the weights assigned to the indices.

Jan 1, 2004

By C. C. Birch

Due to grade estimation uncertainty, two statistical errors can occur. The Type I error is where material is classified as ore and mined, despite the true value being below the break-even grade. This material is dilution. The Type II error is where the material is estimated to be below the cut-off grade and is classified as waste, although the true grade is actually above the break-even grade. This material is not mined and is lost. The uncertainty was assumed to follow a normal distribution in a previous study. For this study, estimated block values are compared to those determined after mining (the best estimate of the true grade). This actual data from four mines shows that the uncertainty follows a Laplace. There is no single solution regarding adjusting the cut-off grade away from the break-even grade, considering estimation uncertainty, that could be applied to all gold mines. However, adjusting the cut-off grade downwards (up to 22% for one mine) is noted when optimizing the profit considering grade uncertainties. This type of adjustment could open up significant mining areas and extend the life of the mine.

Jul 2, 2022

By P. Wiesner, H. –M. Stonner

A brief account is given of the influence of sulphuric acid and chloride ions during the recovery of uranium by solvent extraction, followed by a discussion of the settling behaviour of dispersions and models to represent that behaviour. The paper ends with a description of various methods for the recovery of solvent, which is lost in the solvent-extraction process by entrainment and adsorption on solids and by dissolution.

Jan 1, 1982

By G. R. Sawyer

Although backfilling has been in operation for many years, the methods for selecting appropriate slurry dewatering aids have, in some cases, been rather unsophisticated. This has led to many misconceptions regarding the role of the dewatering aid and its various means of application. Testing procedures employed in the correct selection of any practically applied dewatering aid must mirror the actual working processes in which they are to be used. This constraint necessitates the development of complex testing methods when applied to backfilling. The current testing procedures were scrutinized and their various merits noted. From this study a series of testing methods was evolved which incorporate the best aspects of these testing procedures with novel ideas which would eventually result in the correct selection of the dewatering aid. A major consideration in the application of any of these methods is the modus operandi of the backfilling process, and the relevance of the tests to the process. This work attempts to consolidate the testwork performed in the past and suggest new approaches in the correct selection of acceptable dewatering aids for backfilling.

Jan 1, 1988

By Nelson Sánchez

The Los Bronces Development Project (LBDP) was approved in October 2007 by the Anglo American plc Board at a capital cost of some US$1.74B, and is scheduled to be completed by the end of 2010. The project represents a big step forward for the Los Bronces mine since it will increase the treatment rate by 140%, the mining rate by 64% and almost double copper production during the first four years of the project. This economy of scale will also position Los Bronces as a much bigger and efficient mining operation, better prepared to face adverse market scenarios and allowing Anglo to consolidate its position in base metals. The project addressed numerous scope alternatives such as plant capacity vs mine capacity, cut-off grade strategy to maximise value based on the existing flotation and leaching process, cutback strategy, etc. Main infrastructure aspects of the project are as follows: ?Dump area with 2400Mt capacity for waste and low grade material ?Mining equipment: 1 x electric shovel, 12 x 300t trucks, 1 x drill ?Primary crusher: 60? x 89? ?Three new power lines (144MW capacity) ?Grinding plant at 87kt/day nominal capacity (includes a 4.3km tunnel with a regenerative conveyor belt) ?Grinding plant: 1 SAG mill 40? x 25?, 2 ball mills ?Slurry pipeline (52 km from grinding to flotation plant) with five choke stations ?Flotation plant (rougher, cleaning, regrinding circuits and molybdenum flotation). The history of Los Bronces started in 1867 when it was discovered. In 1978 ENAMI (Government company) sold Los Bronces to Exxon for US$112M. The same year a snow avalanche destroyed San Francisco Flotation Plant. In 1979 the plant was rebuilt at 4.9kt/day and from 1979 to 2002 several plant expansions were made up to 54kt/day capacity. In 2002 Anglo acquired Los Bronces for US$1.3B. The 2002 resource and reserve statement showed reserves at 459Mt at 1.02%CuT and resources at 780Mt at 0.80%CuT. The 2007 statement shows reserves at 1,480Mt at 0.67%CuT and resources at 1,644Mt at 0.45%CuT. Defining the size of a plant expansion is the key challenge that any expansionary project faces. The scope of this paper is a general review of the project, describing all the mining techniques that were used to define the best options that maximise value. In this context, a range of plant capacities (from 58 to 230kt/day) combined with a range of mining capacities (from 83 to 166Mt/a) were evaluated in detail, defining for each option a mine plan, Capex and Opex, and cut-off grade strategy for flotation and leaching processes and the associated Net Present Value (NPV) that was used as the selection criteria. The Los Bronces mineral resources potential provides good growth opportunities for the mine beyond LBDP implementation, offering an exciting invitation to continue studying new initiatives that maximise the value of this deposit.

Jan 1, 2008

Anglo Platinum is in the process of introducing a number of initiatives, varied in nature, on a scale that will impact operations in the short, medium and long-term. The advent of mechanization on a large scale and the introduction of new mining technologies therefore require a different approach to the design of ventilation and cooling systems. In addition, the ventilation and cooling systems serving increasingly deeper operations will place a greater demand on electrical power consumption?this in an environment where power generation is limited and increasingly expensive. Ventilation and cooling systems currently being employed in platinum operations have evolved from practices first pioneered in deep level gold mines. However, in modern and future platinum mines, deepening of operations will take place in a somewhat different environment?particularly in terms of geothermal settings and electrical power utilization. This provides the opportunities to devise novel and energy-efficient ventilation and cooling strategies tailor-made to meet these challenges. The need for refrigeration and cooling at depth will increase the capital and operational cost component of ventilation systems and the medium-term limitations on the availability of electrical power will require the provision of innovative systems. The increased use of diesel-powered vehicles underground, the viability of energy recovery and feasibility of thermal storage opportunities are discussed in this paper. Some of the challenges and the solutions currently proposed in terms of ventilation system design, refrigeration plant selection and chilled water distribution methodologies are described. Changes in strategies core to this discipline that affect the health and safety of employees and the profitability of modern operations are deemed necessary to support the transformations that are envisaged.

Jan 1, 2008

By RT White

For a number of years the steel tube and pipe industry has worked on resolving problems of product quality. These have largely been resolved and new products have been developed to take advantage of new developments. To fully coordinate market acceptance guidance on use of galvanized piping was also required. This was largely achieved locally in 2004 with the publication by the SABS of ARP 060 - Guidance on the use and application of hot dip galvanized steel piping for the transportation of potable water in South Africa. Use of this document is not easy however and a need to have a simple computer model to assist the specifier was identified. Working with a major tube and pipe manufacturer this is now being developed and this paper will provide the background to the model?s development and its intended use. There is still a need for a partner Code of Practice on the performance of galvanized piping in buried conditions and the need for this will be highlighted together with current available information.

Jan 1, 2006

By R. H. English, N. C. Joughin

The results of trials with three stope-face cleaning systems are described. Two of these systems were based on armoured chain conveyors, and the third on a reciprocating-flight conveyor. The operational elements of each system are discussed with reference to their effectiveness, and many problems are highlighted. It is concluded that the reciprocating-flight conveyor is superior, and has the potential for being developed into a system yielding a labour productivity of more than 30 m2 per worker per month and a face advance of 15 m per month working one shift a day.

Jan 1, 1979

A General Meeting and Colloquium was held in Kelvin House, Johannesburg on Wednesday 29th September, 1971. The theme of the Colloquium was "The Ferro-alloy Industry". Prof D. D. Howat (President) was in the Chair. The meeting was attended by 106 delegates and was opened by the President at 10.05 a.m. OBITUARY The President: "It is my sad duty to announce the death of G. C. Needham, Fellow, who joined the Institute in 1966 and passed away on 27th September, 1971. As a mark of respect to the memory of the deceased and in sympathy with the bereaved I would ask you all to rise and observe a few moments silence." MEMBERSHIP The President: "I have much pleasure in announcing that the names of the following candidates, having been published in accordance with By-Law 5.2.2, Council has elected them to membership of the Institute. Fellows: Richard Lloyd Blandy, Brian Roger Borton, Brian Teversham, Peter Donald Dickson. Members: Frederick Brian Peacock, Peter John Stacey, Kenneth Niles Thanstrom, Byron J. Hayley, Ian Flemming Buchan, Abraham Hercules le Roux. Graduate: Ian William Coy. Students: Peter Boesley J ames, Kenneth Brian Perel. TRANSFERS From Member to Fellow: Cecil Eugene Fivaz, Peter Edwards. From Student to Graduate: Roy Stavely Traviss. From Student to associate: William Mitchell. I welcome the new members to the Institute and congratulate those members who have been transferred to a higher grade. COLLOQUIUM The first paper, presented by Mr S. Selmer-Olsen, Consulting Metallurgist, Amcor Limited, on 'Trends in Ferro Alloy Production' was published in the May issue of the Journal and comprised information and data relating to new developments in ferro alloy production in various parts of the world. This was followed by a paper-'Conductivity and Viscosity Properties of Slags produced in ferro-alloy manufacture' by D. 1. Ossin et al. This was a record of laboratory test work on slags containing both lime and magnesia, corresponding with the composition of slags encountered in the production of ferro chrome alloys when a dolomite flux is employed. The third paper-'Review of the work of the Pyrometallurgical Research Group of N.I.M. and Metallurgy Department, Wits.' presented by Dr P. R. Jochens, leader of the Research Group, outlined the progress made on ten different research projects presently under way in the Department of Metallurgy. These projects range from studies of the kinetics and mechanism of the reduction of chromite ores through the determination of the activities of MnO in slags to phase studies and melting point determinations in the alloy systems Cr-Fe-Si-C and Cr-Fe-Si. A new feature of this Colloquium was the introduction of the discussion panel composed of four or five individuals known to have special knowledge or interest in the subject under duscussion. Mr J. J. Coetzee was chairman of the first panel, Professor D. D. Howat of the second and Dr R. E. Robinson of the third. During the discussion of Mr Selmer-Olsen's paper an interesting contribution was made by Mr Jack Hayley of Transalloys (Pty.) Limited who pointed out that the lowest power cost in the U.S.A. was that from the TV A at 6 mils per unit (0,43 cents S.A.) while costs from other sources were 7 to 8 mils per unit (0,50 to 0,57 cents S.A.) He also referred to the use of 'pile sintering' of ore fines plus coke at certain ferro alloy plants in the V.S. and to the recent practice of 'graphitising' the paste used for Soderberg electrodes. The last session in the afternoon was devoted to a group discussion on 'Practical problems in Arc Furnace Operation', Mr H. R. Reid of Middelburg Steel Alloys (Pty) Limited occupying the chair, members of the panel being Mr J. Meintjies (Rand Carbide Limited), Mr J. Benn (Amcor) and Mr E. J. Jackson (Transalloys (Pty.) Limited). Mr Reid initiated the discussion by talking of the design and composition of electrode shoes, mentioning the use of the 85/15 Cu/Zn alloy and the comparison of hollow shoes and shoes cooled by tubes. Mr Meintjies discussed electrode management with particular reference to breakages, and dealt with casing and fin design and the welding of fins. Mr Benn dealt with aspects of closed top furnace operation with particular reference to the control of eruptions in the furnace and indicated that preheating of the raw materials might be well worth considering together with the development of a system for the detection of the water vapour present. Mr J ackson was concerned with shells, linings, refractories and tap holes. He deprecated the use of oxygen for opening the tap hole emphasising how uncontrolled use of oxygen led to loss of shape of the tap hole and quite severe burning out of the front hole resulting in time and labour in repairs. A notable feature of the Colloquium was the free discussion 'from the floor' of the hall. Many valuable and highly pertinent contributions were made spontaneously and usually in reply to some controversial topic raised by the discussion group.

By I. du Plessis

The metallurgical response of a difficult to treat coal and an easy to treat coal orebody were investigated in terms of the coal yield and the coal quality in a basic coal recovery flowsheet. The purpose of this paper is to show trends and derive principles for the treatment of different coal types. This investigation entailed using the LIMN simulator to simulate the metallurgical response by varying the plant operational parameters. The controllable plant variables investigated were: ?Cyclone size ?Screen and hydro-cyclone cut points ?Medium cut density ?Feed particle size distribution.

Jan 1, 2010

By N. C. Steenkamp

Lightning has been observed in dust clouds following open-pit blasting. It is proposed that the occurrence of this phenomenon is related to the physical composition and characterization of the mineral fines that comprise the bulk of the dust cloud. Silicate minerals, which are susceptible to fine fracturing during blasting, generate the initial charge. This is further enhanced by collisions and friction during the turbulent upcast in the post-blast dust cloud. Varying size fractions result in different rates at which these particles drop out of suspension and create a secondary temperature gradient. This results in the creation of two charged zones and increases the potential of developing a discharge in the form of lightning. The ideal prevailing meteorological conditions need to be windless to minimize the effect of particle dissipation and have sufficient moisture toenhance the potential of generating lightning.

Apr 14, 2024