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By B. I. Matshediso, J. Kaavera, E. Shemang, T. K. Dintwe, L. S. Teseletso, K. Fichani

The minerals sector continues to draw attention from policy makers who would want to see both old and new mineral projects add value to the minerals in the host country. The current technological development in the leaching of manganese oxide ores to produce a high-purity manganese sulphate monohydrate, a compound that is used in the manufacture of batteries for electric vehicles or long-life storage cells for the renewable energy market, has led to junior mining companies spearheading this technology in new projects across the globe. In this paper, we researched the high-purity manganese sulphate monohydrate project pipeline and used projected production volumes and C1 cash costs to construct the industry supply curve for six projects, including the K.Hill project owned by Giyani Metals Corporation near Kanye, in the southern part of Botswana. The aim was to determine the ideal conditions that would provide a comparative advantage for further local value addition to high-purity manganese sulphate monohydrate and to the end user product. The results showed that while the estimated C1 cash costs would place the K.Hill project as the second highest cost producer from among five projects, it would nonetheless have healthy profit margins due to the high projected price of high-purity manganese sulphate monohydrate. The study recommended policy options, which, if implemented, could further encourage the exploitation and value addition of battery metals in Botswana.

May 27, 2025

By G. L. Dyer, R. D. Alorro, R. E. Browner

A potential new rare earth extraction process has been suggested (Lazo, et al., 2017) (Lazo, et al., 2018) based on converting the rare earth elements to solid phase rare earth oxalates in an oxalic acid leach. Oxalic acid consumption is a significant issue in the process, therefore to improve the viability of this proposed new extraction method, a process to recover oxalate from the leach solution and recycle oxalic acid is required. A review of the literature and confirmation through thermodynamic analysis of the potential options identified precipitation of calcium or ferrous oxalate as the best potential options. The use of metallic iron to both provide ferrous ions as a precipitant and reduce ferric ions in solution would provide the most economical option, however slow kinetics and unreacted iron created significant issues with this process. The direct use of ferrous ions, while faster and more efficient, produced a precipitate with relatively poor solid/liquid handling characteristics and would require an intermediate stage utilising calcium in regenerating the oxalate. Utilising calcium chloride and oxide created very similar precipitates with better physical properties than the ferrous oxalate and that a reasonable proportion of the oxalate could be recovered before neutralisation of the solution induced precipitation of other phases such as iron oxy-hydroxides and calcium phosphate. The produced calcium oxalate was easily converted to oxalic acid and gypsum via immersion in sulphuric acid. It was also found that there is a significant loss of oxalic acid due to factors other than rare earth oxalate precipitation during leaching. This leads to a maximum oxalate recovery in the range of 50 %.

Jan 1, 2020

By S. C. Maji, U. S. Chattopadyay, S. Chaudhuri, T. Gouri Charan

India is devoid of coking coal resources, which is a vital raw material for coke making. As a result it has to import about 80% coking coal for steel making. Indian National Steel Policy, 2017 has envisaged crude steel production around 300 million tonnes Mt) by the year 2030-31 and forecasts coking coal demand of 161 Mtpa (million tonnes per annum). One way of improving the indigenous resources is to study the performance of existing washeries and to improve the clean coal recovery by adopting suitable technology. A study was carried out, mainly to focus on the fine coal circuit of an existing coking coal washery, to generate the desired quality of clean coal. The operating coking coal washery being studied is presently feeding coal from nine different sources with varying feed ash contents. The coal fines varied in ash content ranging from 19.5% - 43.6%. For treating the coal fines, the washery has operated a spiral for the past few years. Performance studies were carried out, and it was found that the spiral is not efficient in recovering the cleans. Detailed investigations were carried out on the coal fines using flotation techniques, and it was found that to achieve a low ash clean coal, the froth flotation is a much better beneficiation option than a spiral, The studies showed that the recovery of clean coal through a spiral is 67.7% at ash content of 27.0%, while flotation tests showed a recovery of 68.1% at 16.5% ash content. Keywords: Coking coal washery, near gravity material, spiral washer, froth flotation

Jan 1, 2020

By N. P. Mabasa, N. Naudé, A. M. Garbers-Craig

An improved methodology is presented for assessing the economic feasibility and effectiveness of recycling MgO-C and Al2O3-MgO-C refractory bricks, which are widely used in the steelmaking industry. Since approximately 28 Mt of refractory bricks are discarded each year, it is logical to recycle them. When furnaces and ladles are relined, the spent refractory bricks become mixed up, and need to be sorted before recycling. This study examined the use of a hand-held X-ray fluorescence analyser (HH-XRF) to distinguish between spent oxide-based and oxide-carbon-based refractory materials, with special emphasis on spent MgO-C (MC) and Al2O3-MgO-C (AMC) bricks. HH-XRF analysis was conducted on 18 oxide-carbon refractory bricks as well as on MgO-chromite and bauxite-based refractories. X-ray diffraction, reflected light optical microscopy, and scanning electron microscopy with energy dispersive spectroscopy were used to characterize the MgO-C and Al2O3-MgO-C bricks to confirm the accuracy of the HH-XRF analyses. This study also underlined the importance of calibrating the HH-XRF analyser for the refractory bricks to be sorted. The HH-XRF was successful in distinguishing between the different oxide-carbon-based refractory bricks both before and after cleaning. This result is important as it proves that HH-XRF provides a method whereby spent MC and AMC bricks can be sorted quickly and reliably.

Jan 26, 2023

By S. Kauchali

"Underground coal gasification (UCG) is recognized as an efficient mining technique capable of chemically converting the coal from deep coal seams into synthesis gas. Depending on the main constituents of the synthesis gas, chemicals, electricity, or heat can be produced at the surface. This paper provides a high-level graphical method to assist practitioners in developing preliminary gasification processes and experimental programmes prior to detailed designs or field trials. The graphical method identifies theoretical limits of operation for sensible gasification within a thermally balanced region, based primarily on the basic coal chemistry. The analyses of the theoretical outputs are compared to actual field trials from sites in the USA and Australia, with very favourable results. A South African coal is studied to determine the possible synthesis gas outputs achievable using various UCG techniques: controlled retractable injection point (CRIP) and linked vertical wells (LVW). For CRIP techniques, an important result suggests that pyrolysis, and subsequent char production, are important intermediate phenomena allowing for increased thermal efficiencies of UCG. The conclusion is that South African coals need to be studied for pyrolysis-char behaviour as part of any future UCG programme. The results also suggest that UCG with CRIP would be a preferred technology choice for Bosjesspruit coal where pyrolysis dynamics are important. Lastly, the use of CO2 as oxidant in the gasification process is shown to produce syngas with significant higher heating value. Introduction and literature surveyCoal is a commonly utilized fossil fuel, providing over 40% of global electricity demand and about 90% of South Africa’s primary energy needs. However, less than 20% of the known world resources are suitable for possible extraction using conventional surface and underground mining techniques (Andrianopolous,, Korre, and Durucan, 2015). Underground coal gasification (UCG) has the potential to recover the energy stored in coal in an environmentally responsible manner by exploiting seams that are deemed unmineable by traditional methods. The UCG process, if successfully developed, can increase coal reserves substantially. For example, in the Limpopo region of South Africa alone, the estimated potential for UCG gas, based on existing geological records, is over 400 trillion cubic feet (TCF) natural gas equivalent – this is about a hundred times more gas than the existing 4-TCF Pande-Temane natural gas field reserve in Mozambique (de Pontes, Mocumbi, and Sangweni, 2014)."

Oct 1, 2018

By B. Friedrich, A. Birich

Gold has been a metal of special importance for mankind for several thousand years. Its outstanding chemical resistance is an important property of this noble metal, but becomes a disadvantage when it comes to gold recovery. The established processes are based on highly aggressive and toxic reagents. Different alternative leaching reagents with a significantly lower toxicity proved to be promising alternatives in the last decades. Major research activities in this field focused on gold ores, so that leaching of secondary resources were not described sufficiently. Based on literature research and extensive experimental investigations, a reagent assessment was conducted for hydrometallurgical gold recovery from electronic waste. It was found that besides thiourea and halides, thiosulfate in particular represents an alternative of major relevance. A variety of different electronic waste (e-waste) specimens were investigated to identify suitable leaching conditions. As a result, an almost complete and selective gold recovery in less than 48 hours from different electronic waste types and components was achieved by thiosulfate leaching. Within the experiments conducted, it was found that the leaching behaviour of cyanide alternative lixiviants differ strongly from leaching of primary ores. Keywords: Gold leaching, cyanide alternative, thiosulfate, electronic waste

Jan 1, 2020

By S. Gan, E. van Niekerk, L. Birrell, D. Robbertze, L. Ncubi, B. Zhao

Quality assurance and quality control (or QAQC) plays a key role in safeguarding the level of confidence of the data generated during mineral exploration and mine development, and is also part of the reporting code requirements for resource estimation and reporting, as well as mining investment. Implementation of good policies and working protocols in quality management will result in the generation of reliable information, which is critical for decision-making on the future of the mining project. The use of certified reference materials, i.e., standard, blank, and duplicate samples, proves effective and efficient for ensuring the level of data confidence in terms of precision, accuracy, and sample contamination. This is well demonstrated by the practice of QC in the exploration programme for the chrysotile tailings storage facilities of Havelock Mine, using 1254 samples from 53 drill-holes. Different statistical tools were applied to analyse the assay results from these samples. The outcome substantiates that the QC practice established during the Havelock exploration project is aligned to best practice guidelines in the industry. The resource delineated indicates that the tailings material at Havelock could potentially become a significant source of supply to the global magnesium market.

Jul 2, 2022

By L Dyer, G. J. Wilkie, P. Walters, B Tadesse, L. Keeney

Grade Engineering® is a term trademarked by the Cooperative Research Centre for Optimising Resource Extraction (CRC ORE) and includes five key levers for upgrading ores and rejecting waste prior to expensive downstream comminution and mineral processing. These five levers include natural deportment, induced deportment, bulk sorting, particle sorting and gravity separation. Over the past ten years, CRC ORE has progressed a range of technologies that exploit these levers from laboratory proof of concept through to large scale demonstration and validation. This paper details the work carried out by CRC ORE and Curtin University for assessing the amenability of an ore for its natural deportment and particle sorting attributes in an Integrated Screening and Particle Sorting (ISPS) Grade Engineering® process. ISPS is seen as a preferred method for Grade Engineering® as compared to individually operated unit operations as the benefits of each can be complementary. Furthermore, it is suggested that integrating the two levers has two important impacts: 1. Firstly, there is a risk that isolated particle sorting test results will be misinterpreted as being representative of the full sample without considering the mass balance impact of high-grade material that might have been lost in the fines fraction. This fine fraction will not be detected through the particle sorter. 2. Secondly, and potentially of more valuable impact, is that the opportunity may exist to upgrade the feed first through determining if there is a concentration of high grade to the fine (or coarse) fraction which can be separated through screening. Undertaking screening in the preparation stage of the particle sorting process will enable analysis and separation of the fine or coarse fractions of a rock mass. The result of this study provides the mining industry with an independent framework for undertaking an Order of Magnitude (ISPS) Grade Engineering® assessment on a range of constituent ore types. Keywords: Grade engineering, particle sorting, grade by size fractionation

Jan 1, 2020

By D. F. Caicedo, I. A. Brum, L. A. Betancourt

Ferricyanide ()()*is one of the most stable cyanometallic complexes present in the gold mining effluents. This cyanocomplex is hard to degrade by natural attenuation and generates a negative impact on aquatic environments. Although free cyanide (CN-) can be obtained by acidifying the solution, the CN- is lethal for all forms of life. The oxidation of ()()* in a typical photocatalitic system was evaluated with the addition of H2O2. To verify the degradation, chemical parameters, such as free cyanide, the formation of ammonia, nitrate, and total iron were analysed at the end of the process. The degradations obtained were up to 70% in a heterogeneous photocatalysis system with TiO2, and a low rate of dissociation was observed by photolysis. The best result was achieved with the H2O2 and TiO2 photocatalytic system, and the stoichiometric concentration was about 2.5 times less than the peroxide used in the real gold mining industry, reaching 83% degradation. The photocatalytic process obtained less toxic byproducts than the original synthetic ferricyanide used as mining wastewater. Keywords: Cyanide, heterogeneous photocatalysis, titanium dioxide, UV radiation, gold wastewater

Jan 1, 2020

By L. M. Tavares, H. A. Petit, P. P. Cavalcanti

Iron ore pellets experience degradation during handling due low energy impacts and stresses. These impacts lead to volume or surface breakage of the pellets, creating fine particles that accumulate along the process. Some of the particles are in contact with the air and are dragged as dust into the workplace or into the atmosphere. The aerodynamic size of the particles allows them to be potentially inhaled by the workers or to be carried to nearby communities. Dust emission becomes critical at specific locations, such as transfer chutes and stockpiles. This work models the dust generation that occurs in an iron ore pellet stockyard using a methodology that combines experiments to quantify the degradation of the pellets to mathematical modelling of the dust emission mechanisms in the stockyard. First, laboratory tests were used to characterise the amount of mass and the particle size distribution of the dust generated by degradation under controlled conditions. Second, the flow over a stockpile of an iron ore pellet company was simulated with the aid of computational fluid dynamics (CFD) simulations. Third, semiempirical equations linked the data generated by simulations and laboratory tests to estimate the dust emission in the stockyard. Finally, results were validated with measured field data, obtained with a novel online measurement tool. Results suggest that the approach is able to predict dust emission with sufficient accuracy and can be used for further implementation in the management of operations and decision making in order to reduce the environmental impact of the process. Keywords: Iron ore pellets, abrasion, dust emission, mathematical modelling

Jan 1, 2020

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.

The May General Meeting of the Institute was held in Kelvin House, Johannesburg, on 21st May, 1969, at 4.30 p.m. Mr J. K. E. Douglas (Vice-President) was in the Chair. There were also present twenty-two Members, including Messrs F. P. Bath, M. Bareza, A. R. C. Fowler, D. M. Jamieson, C. M. Mavrocordatos, D. G. Maxwell and J. A. Nixon (Council Members), Messrs T. Davidson, G. L. Diering, E. T. Dunstan, D. E. H. French, K. Hodgson, O. A. E. Jackson, A. F. Lee, A. Louw, D. L. Starkey, R. K. Wheeler and M. Youngworth. Four Associate Members including Messrs D. Blair Hook and G. R. Still. One Student Mr N. A. Barcza. Thirteen Visitors, including Messrs S. H. Ash, D. L. G. Bayne, E. Bayne, S. Bell, W. S. Garrett, L. S. Gibbs, R. C. Hamilton, M. Maguire, D. Rose and J. D. van Niekerk. Total Present: Fourty-one. OBITUARY The Vice-President: "It is my sad duty to announce the death of the following member of the Institute: Thomas Spence Haldane, Member, who joined the Institute in 1924 and passed away on 21st December, 1968. As a mark of respect to the memory of the deceased and in sympathy with the bereaved, those present stood and observed silence for a few moments. MINUTES The Vice-President requested that confirmation of the minutes of the previous meeting be held over as they would only be appearing in the Journal of the following month. He also requested that confirmation of the minutes of the 75th Anniversary Meeting be held over. MEMBERSHIP The Vice-President: "I have much pleasure in announcing that the names of the under-mentioned candidates have been published in accordance with By-Law 5.2.2, and Council has elected them to membership of the Institute in the following grades: Members: Gideon Jacob Haumann, Peter John Cumming, Ian Stanley Dudman, Roderick Goldston Murchison. Associate Members: Francois Alwyn Beyers Fouche, Alan Marsh, Johannes Petrus van der Westhuysen, Waldo Edmund Stumpf, Ian Nicholas Ridley. Affiliates: Lutgerus Kolver Jooste, Roger Ainsley Ralph Kebble, Edward John Wainwright, Lewis William Davies. Graduate: Clive Graham Knobbs. MEMBER TRANSFERED TO A HIGHER GRADE From Student to Associate Member: Diethard OUo Eduard Fahrbach. I welcome the newly elected members to the Institute and congratulate the member who has been transferred to a higher grade." (Applause).

The May General Meeting of the Institute was held in Kelvin House, Johannesburg, on 21st May, 1969, at 4.30 p.m. Mr J. K. E. Douglas (Vice-President) was in the Chair. There were also present twenty-two Members, including Messrs F. P. Bath, M. Bareza, A. R. C. Fowler, D. M. Jamieson, C. M. Mavrocordatos, D. G. Maxwell and J. A. Nixon (Council Members), Messrs T. Davidson, G. L. Diering, E. T. Dunstan, D. E. H. French, K. Hodgson, O. A. E. Jackson, A. F. Lee, A. Louw, D. L. Starkey, R. K. Wheeler and M. Youngworth. Four Associate Members including Messrs D. Blair Hook and G. R. Still. One Student Mr N. A. Barcza. Thirteen Visitors, including Messrs S. H. Ash, D. L. G. Bayne, E. Bayne, S. Bell, W. S. Garrett, L. S. Gibbs, R. C. Hamilton, M. Maguire, D. Rose and J. D. van Niekerk. Total Present: Fourty-one. OBITUARY The Vice-President: "It is my sad duty to announce the death of the following member of the Institute: Thomas Spence Haldane, Member, who joined the Institute in 1924 and passed away on 21st December, 1968. As a mark of respect to the memory of the deceased and in sympathy with the bereaved, those present stood and observed silence for a few moments. MINUTES The Vice-President requested that confirmation of the minutes of the previous meeting be held over as they would only be appearing in the Journal of the following month. He also requested that confirmation of the minutes of the 75th Anniversary Meeting be held over. MEMBERSHIP The Vice-President: "I have much pleasure in announcing that the names of the under-mentioned candidates have been published in accordance with By-Law 5.2.2, and Council has elected them to membership of the Institute in the following grades: Members: Gideon Jacob Haumann, Peter John Cumming, Ian Stanley Dudman, Roderick Goldston Murchison. Associate Members: Francois Alwyn Beyers Fouche, Alan Marsh, Johannes Petrus van der Westhuysen, Waldo Edmund Stumpf, Ian Nicholas Ridley. Affiliates: Lutgerus Kolver Jooste, Roger Ainsley Ralph Kebble, Edward John Wainwright, Lewis William Davies. Graduate: Clive Graham Knobbs. MEMBER TRANSFERED TO A HIGHER GRADE From Student to Associate Member: Diethard Otto Eduard Fahrbach. I welcome the newly elected members to the Institute and congratulate the member who has been transferred to a higher grade." (Applause).

By J. K. Pothal, S. Basu, R. Barik, P. K. Senapati, A. Dubey

The aim of this paper is to study the characteristics of limestone particles (size varies from 4 mm to 20 mm) during its transportation from open cast mines through pipes. The influence of four different size fractions of limestone samples (4–6 mm, 6–10 mm, 10–15 mm, and 15–20 mm) on pipe flow characteristics during vertical transport in a 100 mm NB hose pipe was investigated. The flow velocities in the vertically lifting pipe was varied from 0.95 m/s to 2.78 m/s and a rotary feeder of 2 to 4 tonne/hr. capacity was employed to feed the limestone samples to the lifting pipe. The pressure drop data for the different size fractions of limestone samples at different mixture velocities were analysed. The effect of input volume fraction and superficial velocity of limestone samples on hold-up ratio were discussed. It was indicated that there was no substantial increase in pressure drop of slurry samples in the studied range of concentrations (CW = 4.22% - 12.54%), particle size, and low to medium range mixture velocities with respect to water run head loss data. The hold-up for the larger size fractions (15–20 mm) of limestone samples was found to be significant as compared to smaller size fractions, which may be due to terminal settling velocities of individual fractions of the studied samples.

Mar 4, 2025

The March General Meeting of the Institute was held in Kelvin House, Johannesburg on 18th March, 1970, at 4.30 p.m. Mr J. K. E. Douglas (President) was in the Chair. There were also present fifteen Fellows, Messrs H. Britten, R. C. J. Goode, Prof D. D. Howat, Mr T. C. A. Meyer, Dr R. E. Robinson, Messrs V. C. Robinson and P. W. J. van Rensburg (Council Members), S. K. de Kok, Dr N. P. Finkelstein, Messrs K. W. Findlay, H. N. Hepker, J. Levin, Dr K. A. Murray and Mr A. H. Mokken. Four Members including Mr D. Ayres, Dr M. I. Britten and Dr A. Granville. One Associate: Mr G. S. Stander. One Student, Mr R. N. Guest. Four Visitors, Messrs S. A. Allison, C. N. Leibb, C. J. Kooij and A. Mavrogordato. Secretary: Mr D. C. Visser. Total present: Twenty-seven. OBITUARY The President: "It is my sad duty to announce the death of Henrik Johannes Van Eck, Honorary Life Member, who joined the Institute in 1929 and passed away on 18th February, 1970. Dr van Eck started life as a chemist and chemical engineer and, as we all know, he rose to become one of our most distinguished leaders of industry in the country. On many important occasions we, in this Institute, have been privileged to have him address us on subjects which were always of great importance and relevance to the developments in this country. He was a man of great vision and imagination and could put across his ideas in a most eloquent and convincing manner. In his important position as chairman of the Industrial Development Corporation and of Iscor, whatever he said carried great weight. Busy as he was he always found time to participate not only in the affairs of this Institute but in many other technical and public bodies. His passing is a great loss to South Africa and we in this Institute wish to associate ourselves with the many other tributes which have been paid to this great man. We extend our sympathy to his wife and family and as a mark of respect I would ask you to rise and observe a few moments silence." MEMBERSHIP The President: "I have much pleasure in announcing that the names of the undermentioned candidates, having been published in accordance with By-Law 5.2.2, Council has elected them to membership of the Institute in the following grades: Fellow: Ian Douglas Bruce Corner, Joachim Bernhard Rolfes. Member: Michael Vernon Nolan. Associate: Karl Franz Wilhelm Eick. MEMBERS TRANSFERRED TO A HIGHER GRADE From Member to Fellow: Nilo Zolezzi. From Graduate to Member: Roger Billingham. I welcome the newly elected members to the Institute and congratulate the members who have been transferred to a higher grade." PAPERS FOR PRESENTATION The President: (i) "Mr Lee, may I call on you to deliver your paper entitled 'A new bubble pick-up technique as a rapid flotation test method'." After the presentation of the paper the President said: "The paper which Mr Lee introduced this afternoon was a short one but was nonetheless important in that it described a new tool for use in flotation test work. Those of us who have experienced the frustration of trying to solve flotation problems by trial and error methods know what this means. I well remember 25 years ago at T.G.M.E. trying to improve the recovery from the flotation plant there by trying various combinations of reagents and then having to wait a couple of days for the assay office to give results. Even then, on the small scale laboratory tests which had to precede full scale tests one could never be sure that the results obtained were reproducible on the full scale. Here it seems we have a relatively simple apparatus which can measure instantly the effectiveness of various reagents under different concentrations and pH values, etc. It is most important, I believe, that developments of this kind be reported in our journal for the benefit of all involved in such work, not only so that we know about it but also in order to provoke constructive discussion which might lead to further developments. I would like to invite members, therefore, to submit papers or notes on important

The April General Meeting of the Institute was held in Kelvin House, Johannesburg, on 15th April, 1970, at 4.30 p.m. Mr J. K. E. Douglas (President) was in the chair. There were also present eight Fellows: Dr J. M. Bereza, H. Britten, R. C. J. Goode, C. E. Mavrocordatos, P. W. J. van Rensburg (Council Members), C. A. Border, D. E. French and S. D. Hill. Four Members, J. A. Boyd, P. Crawshaw, D. P. Hugo and A. H. Munro. Two Associates, including I. Robinson. Eleven Visitors, including A. B. Gould, P. M. Haupt, B. Needleman and A. F. Wentzel. Secretary, D. C. Visser. Total Present, 27. OBITUARIES The President: "It is my sad duty to announce the death of the following: Leslie Richard Ulyate, Fellow, who joined the Institute in 1939 and passed away on 10th March, 1970. Stanley Sterling, Fellow, and Corresponding Member for Canada, who joined the Institute in 1926 and passed away on 25th March, 1970. 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." MINUTES The President: "May we confirm the minutes of the General Meeting, held on 21st January, 1970, as published in the March, 1970, issue of the Journal?" Agreed. MEMBERSHIP The President: "I have much pleasure in announcing that the names of the undermentioned candidates, having been published in accordance with By-Law 5.2.2., Council has elected them to membership of the Institute in the following grades: Associate: Rupert George CaIcott. Students: Clive Martin Davis, William Machiel Eksteen, Cecil John Tainton. From Student to Member: Dirk Johannes Hugo. "I welcome the newly-elected members to the Institute and congratulate the member who has been transferred to a higher grade." TALK AND FILMS The President: "Mr Ballantyne may I call on you to present your talk and films on the 'Continuous casting of steel'?" After the presentation of Mr Ballantyne's programme the President said, "Thank you very much indeed for your talk and films, Mr Ballantyne. This is a fast developing subject and we appreciate having such up-to-date information being made available to us, particularly those of us who are unable to go overseas for this purpose. We trust that you won't let the matter rest here, but will put everything down in a paper which we can publish at a later stage for the benefit of our members. Thank you once again." CONCLUSION The President: "I wish to thank members and visitors for their attendance, and now declare the meeting closed." The meeting closed at 6.10 p.m.

By H. W. J. P. Neomagus, J. R. Bunt, D. L. Botha, N. T. Leokaoke

Coal briquetting traditionally makes use of high-dosage, nonpolymeric binders (such as coal tar pitch or molasses) or polyvinyl alcohol (PVA) at low dosages for the binding of fine and ultrafine coal. Due to constraints associated with the manufacturing and cost of PVA-bound briquettes, a novel polyacrylic binder was developed that could possibly be added in low dosages at room temperature. A set of formulations of two polyacrylic components (components A and B) was developed, from which an optimal binder mixture was determined. This formulation comprises 40wt.% component A and 10wt.% component B with a 0.04wt.% cross-linking additive, and the balance water. The uniaxial briquette compressive strength was used to obtain the optimal binder mixture. The binder mixture was added to the coal powder in dosages from 0.1 to 1.2wt.%. Mechanical tests and thermogravimetric analysis in an oxidized environment at a maximum temperature of 930°C were conducted. Binder-bound briquettes were compared to binderless briquettes and PVA-bound briquettes. Briquettes made from the polyacrylic formulation had uniaxial compressive strengths double that of the binderless briquette yield strength, as well as the minimum recommended compressive strength of 0.375 MPa. The organic binders did not affect the combustion of the briquettes, since the results compared well with the binderless briquettes. The polyacrylic formulation is considered to be a possible substitute for PVA in terms of mechanical and thermal properties and raw material cost.

Mar 1, 2021

By N. Hamlef

In this study, the effects of heat treatment on phase formation and surface morphology of the Cr-Pt coated system are investigated using X-ray diffraction and electron microscopy techniques. The CrPt andCr4Pt (Cr3Pt - A15 type) phases were formed after heat treatment of the coated samples. Heat treating at 1000°C renders a distinct island coating morphology that is non-continuous in nature. A diffusional model is proposed for this coated system with regards to the surface morphology formation after heat treatment.

Jan 1, 2014

By A. A. Rogozhin, S. I. Anufrieva, A. V. Kurkov

The results of development of technologies for flotation concentration of two types of complex beryllium ores are presented: beryllium-fluorite in apocarbonate metasomatites (Type I) and rare-earthberyllium in feldspar metasomatites (Type II). The researched samples of Type I ores contain a mineral complex that is difficult to separate by fatty acid flotation, including phenakite, bertrandite, fluorite, and carbonate minerals. The ores are characterised by an increased content of fluorite and carbonates. The sample of Type II ore contains such rare-earth minerals as bastnesite and orthite, and a beryllium mineral - cleiophane. The size of individualised grains of cleiophane does not exceed 0.04 mm, which significantly limits the possibility of extracting the mineral into the enrichment concentrates. For the Type I ores, a technological process for the extraction of fluorite using a phosphorus-containing reagent from the class of dialkylphenyl polyethylene glycol esters of phosphoric acid (DAPEGEPhA) has been developed. The use of DAPEGEPhA enables the production of a high-grade fluorite concentrate (95% CaF2). The production of commodity phenakite-bertrandite high-grade (10% BeO) flotation concentrate from the fluorite flotation tailings with using a fatty acid collector is based on binding calcium in the flotation pulp using soda, sodium hydroxide and sodium tripolyphosphate. The use of a combined collector based on fatty acids and DAPEGEPhA made it possible to produce a collective rare-earthberyllium- lithium concentrate with high REE extraction (88%) from the Type II ores. The concentrates obtained are suitable for production of commercial-grade hydrometallurgy products. Keywords: Beryllium ores, flotation, reagents, concentrates, hydrometallurgy products

Jan 1, 2020

By B. Kenealy

A typical deep shaft is President Steyn No. 2 in the Free State, where 9 tonnes of ore are hoisted at about 15 metres per second from 2378 metres below surface. The skips and attachments each weigh 7 tonnes and they are connected by 43 tonnes of rope, so that to hoist the 9 tonnes of payload, a total of 66 tonnes is accelerated from stand still to 55 km/h for each cycle, using an average of 3185 kilowatts of power in the process. The cycle time for the hoisting is 3.22 minutes. The peak power consumption is 6954 kilowatts, which determines the size of the motor used. Is this the right approach? Are larger skips moving at higher speeds the answer? Is there another way?

Jan 1, 1996