Search Documents

"I have been involved in the refractory industry for many years and at some time or another I have designed materials, tested materials, manufactured materials, installed materials, in fact I have done everything except actually chemically analyzed a refractory material.So I would not even begin to tell you how to analyse a refractory material. I'm sure everyone here knows more about chemical analysis than I do.However you could regard me as a customer with and perhaps the insights I have developed may help in putting the role of chemical analysis in the Refractories into perspective.For a start, let's take a step back and ask why we test refractories. The refractories handbook of the American Foundry Association gives four reasons:1. To determine appropriate specification.2. For quality control, to ensure conformance to specifications.3. To provide special property information not available elsewhere.4. For postmortem analysis to determine property changes in service and provideinformation that can point the way to better service.I want to discuss these points with regard to the role of chemical analysis and in particular the abuse of in house chemical analysis facilities. Let me talk first about detelmining appropriate specifications. Most refractory products are made from alumino-silicate raw materials.The phase diagram for alumino and silica is as follows:"

Jan 1, 2014

By R. J. Davidson, M. V. Nkosi, V. Veronsee

When activated carbon is used for the recovery of gold and silver from Witwatersrand gold-plant solutions, severe fouling of the carbon by calcium carbonate is experienced. Also, difficulty is encountered in the retention of the adsorbed silver on the carbon because it is displaced by gold. The acidification of plant pregnant solutions before they are contacted with carbon was therefore investigated as a means of overcoming these shortcomings. The results from batch laboratory experiments on the effect of pH on gold adsorption from plant solutions and from synthetic solutions of high ionic strength indicated reaction rate optima in the region of pH 5 and below pH I. The effect of pH on the equilibrium capacity constant for gold adsorption onto activated carbon was also studied, using both a plant solution and a synthetic solution of high ionic strength. In the case of the plant solution, the results suggested only a marginal change in carbon capacity for gold in the pH range 12 to 6, with significant increases in capacity at lower pH values. In the case of the synthetic solution of high ionic strength, the capacity constant was found to increase steadily as the pH was lowered from 12 to I. It was also found that the gold adsorption capacity of the carbon was significantly better for the synthetic solution. No precipitation of gold from the pregnant solution (gold content approximately 6 g/t) was noted as the pH was decreased to values as low as ,. However, about 25 per cent of the 0,6 g/t silver content was found to have precipitated when a pH value of 3,0 was attained. Further substantial precipitation of silver took place as the pH was lowered further. The investigation was extended by the passing of suitably acidified gold-plant solutions through one or more columns containing activated carbon. Preliminary results showed that the particle size of the carbon had a significant effect on the rate of gold adsorption. No displacement of adsorbed silver by gold was observed to take place at an influent pH of 5. In a typical continuous 'merry-go-round' operation involving three columns in which gold was eluted from the lead column every 48 hours, effluent values averaging 0,001 g/t gold could be consistently achieved under simulated plant-operating conditions. The results were obtained at relatively high velocities of influent solution, resulting in very little hold-up of gold in the carbon-recovery circuit. More than 99,9 per cent of the gold and more than 99,8 per cent of the silver was recovered in the adsorption circuit, while the elution data indicated an average elution recovery of 99,8 per cent of the adsorbed gold and 98,2 per cent of the adsorbed silver. Elution of the carbon was carried out at 91 QC. This involved pretreatment of the carbon with a sodium cyanide solution, followed by elution with deionized water. At a loading flowrate of 66 bed volumes per hour, the indicated take-up of metals on the carbon in the lead column was as follows; 53 k g/t gold, 6 k g/t silver, 57 k g/t copper, 14 k g/t nickel, and I k g/t zinc. Only a trace of cobalt was adsorbed. At an elution rate of 1,7 bed volumes per hour, the lead column was found to be completely stripped in under 5 hours, with concentrations of gold in the eluate reaching 6 to 7 g/l. Besides the excellent adsorption and elution results obtained when acidified pregnant solution was used, no fouling of the carbon was indicated, and the pressure drop across the three columns was considered to be well within practical limits. When compared with conventional zinc precipitation, the carbon process would appear to have considerable economic merit, with strong indications that significant savings would be possible both in capital and operating costs. Further pilot-plant experiments, preferably on a gold plant, would be required before a meaningful cost comparison could be made with the existing process.

Jan 1, 1979

By G. Sommer, R. P. Chaix, G. T. W. Ormrod

Recent developments in the instrumentation and automation of uranium-processing plants by G. SOMMER, Ing. (Grad.) (Visitor), G. T. W. ORMROD (Visitor), and R. P. CHAIX, B.Sc. (Visitor) The paper discusses work at the National Institute for Metallurgy on the evaluation of measuring techniques for the automatic control of free acid in leaching. of the ratio of ferric to ferrous ion in leaching, of pH in liquid-liquid extraction. and of uranium in loaded solvent. Commercially available instruments. and the modifications that have been made to adapt them to South African uranium plants, are also described.

By C. Mueller

In many automated mines, multi media video and audio funtionality has to be combined with sensor information or steering commands, which is the idea of a new, PC based integrated and multi media capable control system. The new control system (Multimedia Control - MMC) bases entirely on TCP/IP networking and internet technology. For the first time, this enables the ‘intelligent’ use of video and audio information: pictures and voice sequences may be forwarded on request only, they may be stored if particular events occur (e.g. video black boxes) and sensor signals as well as actions from the automation system can directly be assigned with multi media sequences. MultiMedia Control entirely bases on object oriented software. It uses most modern software technology. As user interface, only a standard web browser is required. This makes the handling of different machines easy. By using mobile web pads, dedicated local operator interfaces are not required any longer. The service staff just connects to the automated equipment by – wireless –LAN to make required adjustments. Customization is easy using an open Application Programming Interface. Software modules may be added to the system without touching or recompiling existing components. The system was prototyped in 2000 using a demo-application. The performance tests showed very positive results both regarding the control system behaviour and the speed/latency timing behaviour of the multi-media information processed. The system now is slightly reshaped to completely meet the final product requirements. It is expected to be available by the end of 2001. Key words: Machine Automation; Control System; Multi Media; Remote Control; Teleoperation; Ethernet; TCP/IP; Internet Technology; Streaming Video; Quality Assurance; Service; Control Centre.

Sep 1, 2001

By R. J. Durrheim, B. Manzunzu, V. Midzi

Selecting ground motion prediction models (GMPM) is crucial in assessing seismic hazard levels in a specific region. This study investigates the influence of ground motion model (GMM) selection on seismic hazard assessment in Johannesburg, South Africa. Most seismic events affecting Johannesburg are related to mining activities and water ingress into the underground mine voids. The most seismically active regions in South Africa include areas around Klerksdorp, Welkom, and Carletonville. These regions experience a significant number of earthquakes, with mining activities being a major factor contributing to seismic events. Ten ground motion prediction equations were selected from regions of similar tectonics setting and were assessed to see if they correspond to the available local data. Six of these were also compared to the ground motions produced by the earthquake of 14 August 2014, which occurred in the Orkney area, one of the mining areas in South Africa. Sensitivity analyses were also carried out to assess the influence of ground motion prediction equations (GMPE) on the seismic hazard of Johannesburg. The results indicate that the choice of GMPM significantly affects the estimation of seismic hazard levels in Johannesburg. Different GMM can lead to varying ground shaking intensity predictions, impacting risk assessments and engineering design considerations. The findings highlight the importance of carefully selecting appropriate GMM tailored to Johannesburg’s specific geological and tectonic characteristics. Understanding how different models perform in this region is essential for accurate seismic risk mitigation strategies.

Jan 12, 2025

Alexander Sutulov. Mineria Ghilena 1545-1975 (Mining in Chile 1545-1975). Santiago, Centre of Investigation of Mining and Metallurgy, 260 pp. (In Spanish). G. B. Rothenburg. Speciality steels. D.S.A., Noyes Data Corp., 1977. 270 pp. Witbank Middelburg Branch A General Meeting was held at the Wit bank Golf Club on 20th April, 1977, at 17h30. Treatment of waste water An International Research Symposium on New Processes of Waste Water Treatment and Recovery is to be held in London from 6th to 8th September, 1977. It NIM reports Report no. 1708 An examination of the suitability of various reducing agents for the production of ferrochromium. (27th Feb., 1975; re-issued May 1977). Report no. 1724 The preparation and reduction of chrornite pellets containing a reducing agent. (14th Apr., 1975; re-issued Mar. 1977). Report no. 1854 The interaction of pyrite, oxygen, and xanthate. (8th Mar., 1977). Report no. 1876 The ultrasonic determination of the mud level in a thickener and the resin level in an ion-exchange column. (6th May, 1977). Report no. 1878 The electrochemical dissolution of galena in aqueous solutions. (5th May, 1977). Report no. 1881 n-Octylaniline, a new extractant for noble metals.(28th Mar., 1977). Report no. 1883 The determination of iron, chromium, titanium, and tungsten by X-ray-fluorescence spectrometry. (31st Mar., 1977). Report no. 1889 Entropy relations in the formation of complexes of silver (1), mercury (II), and cadmium (II) with llwnodentate liyaruls. (5th May, 1977). Mechanics of granular materials A conference on the above subject is to be held in London on 8th and 9th September, 1977, under the auspices of the Institute of Mathematics and Its Applications.

Jan 1, 1977

By G. G. Stanley

Mechanisms in the autogenous mill and their mathematical representation by G. G. STANLEY, B.Sc. (Eng.) (Wits.), M.E. (Queensland), Ph.D., (Fellow) The special characteristics of the autogenous mill are stated, and a suitable type of model for the mill is presented. Details of the test plant and experimental techniques for obtaining the data for model development are next given. followed by a discussion of the methods developed for the computation of the model parameters, namely the appearance matrix, the abrasion and crushing breakage-rate functions, and the discharge-rate function. Examples of results obtained with the model are given, and finally there is a brief account of confirmatory work on a fullscale autogeneous mill.

Jan 11, 1974

By S. Northey, N. Haque, S. Stoddart, W. Bruckard

Development of new technologies and procedures for managing mineral residues and wastes may benefit from a clear understanding of existing tailing management practices. There is a considerable variability in tailing management techniques used in the Australian copper and gold operations, with associated differences and flow-on effects for the mine site water balance. A database was created, capturing a total of 41 copper and gold processing operations in Australia. The database provides information on tailing generation rates, tailing properties (solids contents and particle size distributions) and tailing storage facility (TSF) types and configurations (e.g. total TSF surface area and wetted surface area). Significant variability was found for the above-mentioned parameters. The solid tailing generation rates ranged from 0.5-37 Mt per annum in 2015. Furthermore, both the solids contents and particle size ranges of the tailing were highly site-specific, and largely dependent on the processing flowsheets. Solids contents of tailings ranged from 45-74% by weight whilst P80 sizes of the concentrator (flotation) feed varied from 75-185 μm. The estimated pumping distance was up to 15 km. The presented data can potentially be used to better tailing management strategies by estimating the potential recoverable water and recycling it, thereby thus reducing tailing footprints. Keywords: Tailing management, tailing storage facility, water balance, mine site, flowsheeting

Jan 1, 2020

The January General Meeting was held at The Moth Hall, Witbank, on Thursday, 30th January, 1969. Mr C. G. Sowry (Chairman of the Witbank/Middelburg Branch) was in the chair. There were also present: Fourteen Members: Messrs A. Bain, A. W. L. Brereton, J. Meintjes, G. Langton, A. C. Hofmyer, J. H. Moore, T. S. Wilmot, B. F. van der Merwe, H. A. Williams, O. T. Wright, J. E. van Aswegen, P. J. Beukes, I. Botha. Six Associate Members: Messrs B. T. Hosking, R. E. Powell, J. B. Cornish, R. Ladner, W. Weber, P. J. Muller. Two Affiliates: Messrs P. B. Cass, W. K. C. Bremer. Nine Visitors. Apologies were received from Messrs G. R. Canny, E. J. Jackson. MINUTES OF THE PREVIOUS GENERAL MEETING It was proposed and accepted that these be taken as read. Proposer, J. Meintjies; seconded, A. W. L. Brereton. 75TH ANNIVERSARY CELEBRATIONS OF THE S.A.I.M.M. The Chairman reminded members of the functions arranged to mark this occasion. It was also mentioned that members desirous of forming parties to travel to Johannesburg should either make arrangements amongst themselves or inform the Secretary who would assist in arrangements. PAPER FOR PRESENTATION The Chairman then called upon Mr S. Selmer-Olsen to present his paper, 'Lectures on electro-smelting of ferro-alloys'. After Mr S. Selmer-Olsen had presented his paper, he answered questions arising from contributions from the floor. The Chairman then thanked Mr S. Selmer-Olsen for presenting his paper. CONTRIBUTIONS TO PREVIOUS PAPERS Contributions to the paper 'Photo-electric readings. Their significance for dust control on collieries,' presented by Messrs G. H. J. Kitson (Member) and Y. J. F. Haven (Visitor), were read by Messrs A. Bain and A. W. L. Brereton.

The Annual General Meeting of the Institute was held in Kelvin House, Johannesburg, on Wednesday, 25th August, 1971, at 4.15 p.m. Mr V. C. Robinson (President) was in the Chair. There were also present fifty one Fellows, twenty one Members, two Associates, two Students and fourteen Visitors, making a total of ninety one. The President declared the meeting open at 4.15 p.m. OBITUARIES The President: 'It is my sad duty to announce the death of the following members of the institute: H. J. G. C. Arndt, Life Member, joined 1933, passed away 11th May, 1971. J. H. A. Diering, Fellow, joined 1921, passed away 24th June, 1971. L. O. W. Leimer, Fellow, joined 1960, passed away 25th June, 1971. E. A. Meltzer, Fellow, joined 1941, passed away April, 1971. As a mark of respect to the memory of the deceased and in sympathy with the bereaved, I would ask you to rise and observe a few moments silence.' MINUTES The President: 'May we confirm the minutes of the General Meeting held on 17th March, 1971, as published in the July, 1971 issue of the Journal?' Agreed. WELCOME TO VISITORS The President: In welcoming you here, ladies and gentlemen, it gives me great pleasure to see so many of our office bearers-our important honorary office bearers-and particularly I would like to welcome our Honorary President, who is, as you know, the President of the Chamber of Mines, Mr John Shilling, and we are 'privileged also to have with us two of our Honorary Vice-Presidents. One in particular I am very pleased to welcome here, and that is Mr G. F. van L. Froneman, who is the Administrator of the Orange Free State, and we extend a very hearty welcome to him, because he is a long way from home. Then we have another Honorary Vice-President, Mr Tommy Gibbs, the Government Mining Engineer, and there are many distinguished guests, whose names I want to give you, so that you will know who they are. We are happy to have present: Mr R. C. J. Goode, Member of Council, I.M.M. London; Mr E. Boden, Manager, A.S. & T.S. of S.A.; Mr G. A. P. Louw, The President, The Associated Scientific and Technical Societies of S.A.; Mr I. R. G. Stephen, The President, The South African Institution of Electrical Engineers; Mr A. S. Robinson, The President, The South African Institution of Civil Engineers; Mr C. F. J. Schneider, The President, The Institute of Land Surveyors of the Transvaal; Mr R. J. Vermaak, The President, The South African Institute of Assayers & Analysts; Prof J. P. F. Sellschop, The President, Joint Council of S.A. Scientific Societies; Mr T. C. Watermeyer, The President, The Federation of Societies of Professional Engineers; Mr G. A. MacWhirther, The President, S.E.I.F.S.A.; Mr C. G. Hinds, The President, The Mine Managers Association; Mr J. F. Aldersley, The President, The South African Institute of Foundrymen; Dr H. O. Reisener, The President, The Institute of Welding; Dr F. P. A. Robinson, The President, S.A. Corrosion Council; Mr A. Bain, The Chairman, Witbank-Middelburg Branch; Prof D. J. Schoeman, The Chairman, The S.A. Institution of Chemical Engineers; Dr N. P. Finkelstein, The Chairman, The South African Chemical Institute (S.Tvl Section); Mr J. M. Meyer, Chairman, O.F.S. Branch. To all these guests and their ladies, I extend a most cordial welcome, and hope that you are going to enjoy the afternoon. MEMBERSHIP The President: 'I have 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 in the following grades: Fellows: Richard Lloyd Blandy, Byron J. Haley. Members: Brian Roger Borton, Frederick Brian Peacock, Peter John Stacey, Kenneth Niles Thanstrom. Students: Peter Boesley James, Kenneth Brian Perel. TRANSFERS From Member to Fellow: Cecil Eugene Fivaz, Peter Edwards. I wish to welcome the new members to the Institute and to congratulate those members who have been transferred to a higher grade. ANNUAL REPORT OF THE COUNCIL AND ACCOUNTS FOR THE YEAR ENDED 30TH JUNE 1971 THE PRESIDENT: We now come, ladies and gentlemen, to the annual report of the Council of the Institute-and our accounts for the year ended 30th June, 1971, and these documents are on your chairs; I know you probably haven't had time to study them yet, but I would like to highlight some of the things which I think are worth mentioning. I would ask you to take, first of all, ladies and gentlemen, the report of the Council as being read, and before moving adoption, however, there are certain salient points I wish to touch on, and I will leave the financial side of this entirely to our very competent and worthy, Honorary Treasurer, Mr Denis Maxwell.

Metso Minerals Cisa have developed VisiofrothTM - a system which calculates parameters of the froth surface using vision from remote cameras mounted about individual flotation cells. The parameters calculated from this system can be utilised within process control strategies to achieve stabilisation or optimisation of the flotation process. As part of a JKMRC AMIRA P9 field campaign, froth vision was collected from various cells operated at different air rates and froth depths within Rio Tinto's Northparkes copper roughing and scavenging circuit. At the same time, samples were collected to determine the cell metallurgical performance at each operating condition. These froth images have been processed using the VisiofrothTM system with froth velocity, bubble size, froth collapse rate and various froth colour parameters calculated. These parameters have been compared to the measured concentrate flow and concentrate grade produced at each condition. This analysis shows that the concentrate tonnage flow is strongly correlated with froth velocity whereas the concentrate grade is best correlated using froth velocity in combination with a bubble stability parameter which affects the bubble size distribution on the top surface of the froth. This paper summarises the results from this analysis as well as an overview of the VisiofrothTM system and the parameters that are measured by the software.

Jan 1, 2007

By D. Sethuram, P. G. Koppad, S. Iyengar, R. Shobha

TiB2 and CeO2 particle-reinforced Al6061 hybrid composites were manufactured using stir casting and hot rolling techniques. The base alloy and composites were hot-rolled at 500ºC and a 50% reduction was achieved through 12 passes. The effect of varying TiB2 and CeO2 particle additions on the microstructure and mechanical properties of the Al6061 matrix was studied. Scanning electron microscopy showed uniform dispersion of both the reinforcements, with good interfacial bonding. Microhardness and tensile properties like yield and tensile strength were found to be higher for hybrid composite with 2.5% TiB2 and 2.5% CeO2 compared to Al6061 alloy and other hybrid composites. The increased tensile strength is attributed to good dispersion and interfacial bonding between the particles and Al6061 matrix. Fracture analysis using a scanning electron microscope revealed ductile fracture for the Al6061 alloy and mixed characteristics of ductile-brittle fracture for hybrid composites

Oct 1, 2021

By S. V. Rungan

The modern mining industry is increasingly being tasked to comply with various legal, industry and social prerequisites. In addition to complying with these, the mining industry is further expected to effectively report on their compliance. Although there are many models that aid the mining industry in compliance and reporting, it is perhaps opportune for a new model to be introduced. The Compliance Spindle is postulated as a new and alternative model which is easy to understand and has the possibility of implementation in South Africa and other jurisdictions as well. The Compliance Spindle is also an effective tool to educate future compliance officers. The new model provides for all aspects of compliance and reporting and can be easily modified to take account of new developments in the mining compliance and reporting arena.

Jan 1, 2010

COUNCIL AND STANDING COMMITTEES - 1973-1974 Office Bearers: P. W. J. van Rensburg (President), Professor R. P. Plewman and Dr R. E. Robinson (Vice Presidents), J. K. E. Douglas (Honorary Treasurer), and Dr J. P. Hugo (Immediate Past President). Elected Members of Council: Dr M. G. Atmore, G. H. Grange, Dr P. R. Jochens, J. G. Kirchner, Dr D. I. Legge, W. W. Malan, Dr M. D. G. Salamon, L. W. P. van den Bosch, D. A. Viljoen, P. A. von Wielligh. Branch Chairmen: B. T. Hosking (Witbank-Middelburg Branch), E. T. Wilson (Orange Free State Branch). Past Presidents Serving on Council: R. J. Adamson, M. Barcza, H. Britten, H. E. Cross, Professor J. de V. Lambrechts, R. C. J. Goode, Professor D. D. Howat, D. M. Jamieson, D. G. Maxwell, Dr J. T. McIntyre, V. C. Robinson. Ten Council meetings were held during the year, with an average attendance of 19, and the standing committees held 30 meetings. COMMITTEE CHAIRMEN Membership, Dr R. E. Robinson ; Metallurgical Colloquia, Dr R. E. Robinson ; Mining Colloquia, L. W. P. van den Bosch; Awards, P. W. J. van Rensburg; Excursions, P. A. von Wielligh; Dinner, G. H. Grange ; Constitution, Rules and Policy, Dr J. P. Hugo; Adjudicating, P. W. J. van Rensburg; Mines and Works, W. W. Malan; Education, Dr J. P. Hugo. REPRESENTATIVES ON OTHER BODIES Associated Scientific and Technical Societies: Members : V. C. Robinson and D. G. Maxwell Alternates : P. W. J. van Rensburg and Dr J. P. Hugo. Federation of Societies of Professional Engineers Members : J. K. E. Douglas and P. W. J. van Rensburg Alternates : Dr J. P. Hugo and G. H. Grange. South African Council for Professional Engineers Members : R. C. J. Goode and J. K. E. Douglas Alternates: G. H. Grange and Dr R. E. Robinson. Engineers' Liaison Committee (Pretoria): Member: Professor J. de V. Lambrechts Alternate : Dr J. P. Hugo. MEMBERSHIP Seventeen Fellows and Members, twenty-three Graduates, ten Associate Members, twenty-two Associates, thirty-four Students, and seven Company Affiliates were elected during the year. Eleven Fellows and four Members were admitted to retired membership. Five Fellows were elected to Honorary Life Membership. Four Members, two Graduates, and one Student were transferred to Fellows ; eleven Graduates and Students were transferred to Members ; eight Students to Graduates; and four Students to Associates. A statement of membership as at June 30th 1974 and the end of the previous year is given in the following tabulation 30th - 30th June, - June, 1973 - 1974 Honorary Life Fellows 4 - 9 Honorary Fellows 9 - 8 Life Fellows 177 - 170 Fellows 536 - 544 Members 487 - 512 Associate Members - - 10 Graduates 128 - 130 Associates 186 - 194 Students 183 - 173 Company Affiliates 64 - 70 1 774 - 1 820 OBITUARIES Your Council records with deep regret the death during the year of the following members : Dr P. N. Lategan and Dr O. A. Jackson, Honorary Life Fellows and Past Presidents; C. Airth, T. L. Blunt, J. B. Dennison, A. E. Frazer, C. L. Lamb, V. O. Reid, K. Richardson and D. G. Roberts, Life Fellows ; H. F. Allan, J. T. Beaumont, M. Eisenstein, J. C. Hall, C. F. Louw, H. H. McGregor, R. Murchison, and J. E. Williamson, Fellows; and R. B. Miles, Associate. FINANCE The annual accounts, which follow this report, reflect a healthy position and show that measures taken by Council over the last few years to boost income have been successful. A higher income was needed not only to meet rising costs but also so that the services provided by the Institute for its members could be expanded. This year's income of R55 025 showed a further increase compared with last year's figure of R48 307. Income from subscriptions was higher mainly owing to an increased number of Company Affiliates, and this is indicative of the support given by mining and metallurgical companies to the good work being done by the Institute. Further sales of publications of the symposia held over the last few years again made a useful contribution to income of R4560. The first Winter School held in 1973 yielded a surplus of R7495 after the expenses had been deducted from the income received from registration fees. The cost of administering the Institute increased by R2212 compared with the previous year. Included in this was a donation of R1000 to the A.S. & T.S. Trust Fund. The cost of publishing and printing the Journal increased by R2034, but advertising and extraneous sales of the Journal were higher, with the result that the net cost of the

Jan 10, 1974

Professor G.T. van Rooyen has guided the Department of Materials Science and Metallurgical Engineering at the University of Pretoria in South Africa for the past 32 years. During this period, 54 masters' degrees have been awarded in the Department, and 17 doctorandi promoted. He has also made a major contribution to industry by his incisive analysis, relevant and practical synthesis, and his exceptional talent in innovative design. He is still active in fracture analysis, thermal fatigue, weld simulation transformation kinetics, and fracture mechanics, and continues to contribute to a better understanding of metallurgical problems encountered in practice. He has advised many companies, and has received many honours and recognitions.

Jan 1, 1994

By A. J. Dickson, A. M. Starfield

This paper reviews the progress made to date in the development of computer models of heat and moisture transfer from rock surfaces to the ventilating air in deep-level mines. The application of these programs to ventilation planning and design is discussed.

Jan 1, 2014

A. Sutherland Brown (ed.). Porphyry deposits of the Canadian Cordillera. The Canadian Institute of Mining and Metallurgy, Special Volume 17, 1976. C. G. Down and J. Stocks. Environmental impact of mining. G. B. Rothenberg. Refractory minerals. Park Ridge (V.S.A.), Noyes Data Corporation, 1976. Geology, mining and extractive processing of uranium. London, Institution of Mining and Metallurgy, 1977.

Jan 1, 1978

By S. Fuchida, Y. O. Zubair, C. Tokoro

Mining of As-bearing minerals had resulted in the release of arsenic species predominantly As(III), which is known to be more toxic, and undue exposure to it is detrimental to human organ systems. Many materials have been examined for As(III) removal, but it is still challenging to advance sustainable materials for effective removal of As(III). In this paper, a more eco-friendly and superparamagnetic Fe0-Fe3O4 composite was synthesised and evaluated for heterogeneous catalytic oxidation and removal of As(III) with peroxymonosulfate (PMS, KHSO5). The kinetic removal studies showed that removal of As(III) was probably through a chemical process and the Elovich model best represented the experimental data. The removal capacity for As(III) on Fe0-Fe3O4 with PMS (1.76 mmol/g) is superior to that without PMS (0.83 mmol/g). Combined results from XPS and ESR showed that As(III) was fully transformed to As(V) through catalytic oxidation by Fe0-Fe3O4/PMS and afterwards enhanced its removal. The removal mechanism of arsenic was ascribed to the formation of outer-sphere (electrostatic attraction) and inner-sphere complexes. The adsorbent can be separated easily from water due to its excellent magnetisation (64.5 emu/g) and also has good reusability potential as more than 85% of the initial concentration of As(III) was immobilised after five consecutive cycles. Keywords: Arsenite, Fe0-Fe3O4 composite, catalytic oxidation, removal mechanism

Jan 1, 2020

By B.E. Hall

Maximizing shareholder value has become a common aim for mining companies. This paper discusses the results of a number of studies developing strategic mine plans, covering a wide range of commodities, styles of mineralization, mining methods, and processing facilities, for single and multiple deposits. It has become evident that traditional methods and conventional wisdom often do not in fact achieve these goals. Operating policies at many mines ensure that shareholder value is not maximized. Changing the overall strategy can provide significant value gains. Typically, the new optimal plan involves a significant increase in the cutoff grade, at least in the earlier years. An increase in the underground development rate or open cut stripping rate is often associated with this, at least in the short term, to establish the new strategy. Cost minimization is found to be counter-productive. Counter-intuitive plans are often found to be optimal. For example, optimal cutoffs for different parts of an underground mine may be significantly different, even if mineralisation and cost structures are similar. Sub-optimal strategies are also frequently found to have a significantly greater financial risk than optimal plans, which have been found in many cases to be relatively insensitive to changes in major value drivers, such as metal prices. This paper shows how identifying and then operating within the framework of an optimal strategic plan can have substantial benefits over being continually driven by short-term tactical issues.

Jan 1, 2009

By G. T. van Rooyen

In this overview of materials engineering, the author, drawing on his long experience from his student days until the present (emeritus professorship), briefly recounts the main developments in this field: dislocation theory, fracture problems, and the development of alternative materials such as ceramics and polymers. He then takes a look at the future, in which he foresees a greater demand for materials engineers, and leading roles for universities and technikons in collaboration with industry.

Jan 1, 1996