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The nature of metallurgical engineering?applying and optimising chemical and physical processing of ores into useful materials?is reviewed. Important trends that shape the context in which metallurgical engineers practise are identified ? increased global production of primary metals, declining prices, environmental constraints, and increased property requirements of materials. A successful department of metallurgical engineering is one which employs a team of academic leaders to develop graduate engineers who are productive across the full range of metallurgical processing. Keywords: metallurgical engineering, primary metals, commodity prices, processing

Jan 1, 2003

By L. Tartibu, S. Assuli, P. Nkul, A. Kabimba, W. Elongo, N. Makhotla, D. F. Verwey, F. G. Ndiitwani, J. Bilali, T. Mukongo

The presence of colloidal silica negatively impacts various hydrometallurgy processes. This paper details the nature of colloidal silica, operational issues caused by colloidal silica, as well as various mitigation measures. MMG Kinsevere observed severe phase-continuity instability, increased crud formation, and reagent consumption, and reduced current efficiency in electrowinning with a deterioration in copper quality. Historical mitigation measures were initially implemented but failed to solve the problem. MMG Kinsevere successfully achieved efficient silica removal without adverse effect on the solvent extraction with the use of DEHSCOFIX® SC12 coagulant. A week into the coagulant trial, silica concentration had dropped from > 1500 mg/L to within 500 mg/L. The solventextraction plant recovered its stability and again operated at maximum capacity. Additionally, improvement was observed on current efficiency and copper cathodes quality with use of the coagulant.

Jan 1, 2023

By Y. J. F. Haven, G. H. J. Kitson, D. G. Beadle

I have read this paper with considerable interest. By using an automatic instrument to assess the dust samples taken in South African collieries, the authors are ahead of the gold mining industry, which still uses the laborious method of microscopic assessment, with its limited accuracy, of the half-a-million dust samples taken each year. As the authors state, the result obtained from the photoelectric assessment of the samples is approximately proportional to the surface area of the respirable dust. However, modern theory is that, in assessing coal dust, it is the respirable mass which is important in determining the danger to health. Thus Table II of their paper is of considerable value in showing the relationship between the P.E.R. value and the mass concentration measurement. Unfortunately this table only gives the mean relationship. The important point is to know the scatter around this mean. If the scatter is small, then this mean value (for different operations) would have considerable value in converting from respirable surface area to respirable mass, but if the scatter is large, then such a conversion, using a fixed factor, will have little value. In the text the authors mention the range of values as being between 3 to 24, but without a statement on the number of samples used to determine this range and their distribution, this is a rather nebulous statement. I hope, in their reply, that the authors will give, in statistical terms, some statement on the overall correlation between these two parameters. I might add that at present a member of my staff is working on similar relationships for dust samples taken in gold mines. Another factor which may well be most important in determining the danger of dust levels in coal mines is the composition of the dust, specifically its quartz content. I understand that the authors have some information on this point, and to make their results of greater value in International comparisons of dust levels and the concomitant development of pneumoconiosis, it will be extremely useful if they could place this information on record. Even though, as I have said above, modern theory postulates that respirable mass is a better parameter to use than respirable surface area, the problem remains of how to measure this parameter with short time sampling, which, as the authors point out, is their preferred strategy for dust sampling and dust control. I know of no easily portable instrument, independent of external power supplies, which can, in 5 to 10 minutes, collect sufficient dust to enable it to be weighed accurately. Thus the authors' implied intention of continuing to sample by their present techniques and using their present parameter to report the results is, in my opinion, an entirely valid decision.

Jan 10, 1968

Notices STRASZACKERREPORT The Institute has received, for its information, a copy of the following letter, which was addressed to The Federation of Societies of Professional Engineers: REPORT: COMMISSION OF ENQUIRY INTO THE METHODS OF TRAINING FOR UNIVERSITY DEGREES IN ENGINEERING (STRASZACKER REPORT) Geagte Heer, VERSLAG: KOMMISSIE VAN ONDERSOEK NA DIE METODE VAN OPLEIDING VIR UNIVERSITEITSGRADE IN INGENIEURSWESE (STRASZACKERVERSLAG) Second International Symposium on Jet Cutting Technology This symposium, sponsored and organised by BHRA Fluid Engineering, of Cranfield, England, is to be held at St John's College, Cambridge, from 2nd to 4th April, 1974. Competition for student members of the South African Institute of Mining and Metallurgy Each year the Institute offers a prize (or prizes should the entries warrant it) of up to R100 for the best paper or dissertation on a topic appropriate to the interests of the Institute. Techomin 74 - World Mining Fair The above World Mining Fair, under the sponsorship of the International Committee for the Organization of World Mining Congresses and the Peruvian Government, is to be held in Lima, Peru, from 3rd to 12th November, 1974, to coincide with the 1974 World Mining Congress, which is to be held in Lima. NIM Reports Report No. 1435 The determination of chromium, manganese, iron, cobalt, and nickel by atomicabsorption spectrophotometry using the nitrous oxide-acetylene flame. Report No. 1463 Liq'uidus temperatures and activities of manganese (11) oxide in slags associated with the production of high-carbon ferromanganese alloys. Report No. 1467 The spectral analysis of solutions. 1. The analysis of rare-earth minerals. Report No. 1479 Infrared studies of the adsorption of oleate species on mineral surfaces,with special reference to fluorite. Report No. 1483 The South African manpower requirements in extractive metallurgy. Report No. 1484 Cost estimates for the production of copper wirebars from sulphidic ores. Report No. 1486 Review of the jluoro-chemical industry of the World. Report No. 1490 The adsorption of krypton, nitrogen, and water vapour on sodium oleate. Report No. 1491 Technology and economics of the Olaus kiln under South African conditions. De Beers Report The dry grinding of tungsten carbide/ steel combinations with diamond wheels. Metallurgical Directory The Israel Export Institute has just published the first edition of the Israel Metal Industry Directory, which gives pertinent information relating to the 750 Israeli manufacturers of metal products-addresses, annual turnover, and products- and to consulting engineers and export companies specializing in metal products. Visiting Nuclear Scientist The National Institute for Metallurgy has announced that Professor Vincent P. Guinn, of the University of California, is to spend his sabbatical leave (April to June) working with the Activation Analysis Research Group of the National Institute for Metallurgy.

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 M. Berjak, D. M. Hawkins, V. E. Marting, R. B. MacGillivray

Contributions to discussion V. E. Marting (Associate Member): The authors of this paper should be congratulated in having pioneered the application of the Sharapov predictor to local data, and in having made a valuable contribution to South African experience in the quantitative treatment of geological information using a digital computer. Although the existing set of three programmes has been described as a 'suite' it does not represent an integrated system in the accepted sense since the communication between runs is made in the form of punched card files to enable the mining engineer to exercise discretion and control over the data entered at each phase. Although the authors are justifiably proud of the successful results obtained through the application of this method, I feel that it is my duty to comment that the computer aspect of the work has not reached full development and is deserving of the financial support needed to increase its widest usefulness. At the present moment a routine to detect 'missing information' has not been commissioned. Due to the lack of documentation the use of the programmes is restricted since the format for the submission of data is known only to the authors. It is very unlikely that a profitable return on the development costs will be enjoyed before the programme is fully documented and made available to wider use. My criticism of the present incomplete state of the work is being voiced purely with the intent of focussing on the significance of this project and the fact that it is deserving of development on an industry basis. It should be noted that at the economical cost of R4.00 per sq ft of computer print-out, a mining engineer can hardly afford to miss the opportunity of using the programmes on other (e.g. metalliferous) mineral deposits of tabular formation. Since the publication of this paper I have had an opportunity to see the results of the programmes developed by Drs M. D. G. Salamon and F. Deist for designing bord and pillar workings. The basic data for these latter programmes are extracted from iso-line plans drawn conventionally by geologists, a task that could be considerably expedited through the use of Mr Hawkins' programmes. It appears that the efforts of these respective teams are complementary and it is in the interests of the industry that these individual components should eventually form part of an integrated system. E. Margo* (Member): This paper is a good example of how and where the backroom scientist-in this case the mathematical statistician-can aid the mining engineer to develop not only more accurate means for dealing with valuation problems but to develop a tool that can also cope with changed geological specifications.

Jan 1, 1969

By J. L. Havenga, L. J. van der Walt, J. T. Nel

"SynopsisThe development of plasma technology at Necsa started in the early 1980s, when the applicability of high-temperature plasmas in the nuclear fuel cycle was investigated. Since 1995, this plasma expertise has expanded to other industrial applications, for example mineral beneficiation, nanotechnology, fluorocarbon production and waste treatment, all of which are also of relevance to the nuclear industry.Necsa has demonstrated the manufacture of plasma-dissociated zircon, zirconium metal powder, carbon nanotubes, silicon carbide (SiC), zirconium carbide (ZrC) and boron carbide (B4C) at the laboratory and pilot plant scale. These materials are commonly used in the nuclear industry. Zirconium alloys are used as fuel cladding material for nuclear fuel assemblies.Necsa manufactured the monomer tetrafluoroethylene (TFE), using 150 and 450 kW DC plasma systems, from which the polymer polytetrafluoroethylene (PTFE) was synthesized for use in filters and as seals in nuclear plants. With the nuclear renaissance at hand, it was demonstrated that plasma technology can be used to produce hydrofluoric acid (HF), which is used in the manufacture of fluorine gas (F2) for the production of uranium hexafluoride (UF6) directly from the mineral calcium fluoride (CaF2) without the use of sulphuric acid as in the conventional process. The recovery of valuable uranium from nuclear waste such as filters, oils, and solids with plasma processes will also be discussed. The destruction of low-level nuclear waste by a plasma gasification system can reduce the volume of this waste by several orders in magnitude, resulting in huge savings in the storage costs. Another product of plasma technology is the encapsulation process for nuclear waste and the production of vitrified product, which could be used as filler material for medium-level nuclear waste.IntroductionDuring the 1980s, a plasma research and development programme was launched at the erstwhile Uranium Enrichment Corporation of South Africa (UCOR) at Valindaba outside Pretoria. The main purpose of this programme was to develop alternative and more economical processes for the processing and manufacturing of uranium compounds used in the nuclear fuel cycle. The conversion of UO2 (as received from uranium mines) to UF6, which is needed for enrichment, conventionally involves several laborious, expensive, chemical processing steps. Plasma processes can eliminate several of the intermediate steps. Enriched UF6 is converted to UO2, which is pressed into pellets that are used in nuclear power plants. Plasma technology could also be used in a modified and optimized conversion process."

Jan 1, 2015

1. New books Extractionmetallurgy'81. London, Institution of Mining and Metallurgy, 1981. 441 pp. $40. Structures and properties of engineering alloys, by W. F. Smith. London, McGraw-Hill, 1981. 512 pp. R89,65. Rock and mineral analysis, by W. M. Johnson and J. A. Maxwell (editors). 2nd ed. New York, Wiley, 1981. 424 pp. $40. Mining methods and equipment, by Mining Information Services. London, McGraw-Hill, 1981. 218 pp. International directory of acronyms in library, information and computer sciences, by P. M. Vaillancourt. New York, Bowker Publishing Co., 1980.516 pp. 2. New journals Trends in analytical chemistry (TRAC), Amsterdam, Elsevier, 12 issues per year. Subs. for Volume I (16 issues) D.H 95.50. Engineering management international, Amsterdam, Elsevier, 4 issues per year. V.S. $32.50, D.H. 70.00. 3. Mineral policy sector publications Mineral Bulletin MR 188. Vanadium: an imported mineral commodity. $3.60. Mineral Bulletin MR 190. Canadian mines: 1980 perspective. $3.00. Canadian mineral survey 1980, by the staff of Mineral Policy and Energy Sectors. $1.00. 4. NIM reports Report 2090 Observations made during the dig-out of a 48 MV A ferrochromium furnace. Report 2110 The investigation of a fracture on one side of a skip bridle in a mine shaft. Report 2111 Pilot-plant tests for the recovery of chromite and the noble metals from the UG-2 Reef at Maandagshoek. Report 2112 The behaviour of UG-2 chromite concentrates during smeUing. Report 2113 M uUivariable control of a milling circuit at East Driefontein Gold Mine. Report 2115 Estimation of material variation in powdered materials Report 2116 Optimum operation of a direct-reading spectrometer with excitation by a 5 kW inductively coupled plasma torch. Report 2121 Five robust indicators of central value. Report 2124 The direct determination, by differential pulse anodicstripping voUammetry at the thin mercury-film electrode,of cadmium, lead, and copper. Report 2127 The preparation of a reference material of South African zirconium concentrate from Richards Bay. Report 2128 The determination, by differential pulse anodic-stripping voltammetry at the thin mercury-film electrode, of cadmium and thallium in six NIMROC reference materials Report 2130 The organizing of conferences. Research grant The Board of Directors of International Precious Metals Institute in conjunction with Gemini Industries, Inc., a California-based refiner of precious metals, recently announced a Gemini Research Grant of $3000 will be awarded annually to a graduate student who is pursuing studies in metallurgy, chemical processes as it pertains to precious metals, or materials sciences, and who is performing or planning research studies in the precious metals. Accidents and diseases The Third International Colloquium for the Prevention of Occupational Accidents and Diseases in the Iron and Metal Industry is to be held on 15th and 16th June, 1982, in Palma de Mallorca, Spain.

Jan 1, 1981

By Z. Botha

Sheryl Sandberg, the COO of Facebook, published a book titled 'Lean In', where she invites women to sit at the table. In summary, to 'sit at the table' entails not only embracing opportunity, but to actively seek out opportunities in leadership positions. Sandberg points out that, unfortunately, apart from institutional obstacles, a woman's own perceived limitations have a negative impact on her leadership ambitions. To create an environment where diversity will flourish, where everyone has a seat at the table and everyone has a voice, safety must be established first. To establish safety within a diverse team, there is power in relationships and connections. This study will first and foremost review theories in literature as to why diversity and inclusion are so important and the value that diversity brings to our industry. The study also recommends a few focus areas for improving diversity and inclusion in the industry.

Sep 1, 2022

By NIM REPORTS

Notices CONFRRENCE ON COMPUTRRS IN ENGINEERING The above Conference, which is being organized by the Electrical and Electronics Board of the Institution of Engineer!!, Australia, ill to be held in Sydney on 16th and 17th May, 1974. It is being planned in conjunction with the Sixth Australian Computer Conference and will be held during the week immediately preceding the latter. NIM REPORTS Report No. 1495 A method for the determination of ekmental sulphur on the surface of sulphide minerals. Report No. 1500 The chromatographic separation and determination of nobk metals in matte-leach residues. Report No. 1505 The production of the refractory aluminium saicates, with special refererence to South Africa. Report No. 1517 Computer-controlled flotation plants in Canada and Finland. Report No. 1526 Heat of solution as a control of aqueous-ammonia concentration. Report No. 1529 South African costs of equipment for the metallurgical industry (197).

Jan 9, 1973

R. C. J. Goode (President): South Africa is known for its sunshine and mineral deposits-especially its gold and its diamonds-and as this year marks the 75th Anniversary of the establishment of the South African Institute of Mining and Metallurgy, it is appropriate that I say a few words about mining and metallurgy and the part this industry and our Institute has played in the life of this country. Africa, as the Dark Continent, with its fascinating tales of Prester John, Ophir, Queen of Sheba and its myths and legends has throughout the ages fired the public imagination. Pharaoh Necho, 600 years before the birth of Christ, sent an expedition from Egypt around the Cape to probe this strange land. The gold for King Solomon's throne was said to come from Monomotapa-the country now known as Rhodesia. Centuries later the Arabs and Portuguese searched for this mineral wealth. The Arabs found little gold but unfortunately established a lucrative trade in black slaves. Now let us take a brief look into the closing stages of the Stone Age when the indigenous population of the lower portion of this continent consisted of the Bushmen, a nomadic hunting people who knew no metals and kept no stock, and the Hottentots who were a pastoral folk with cattle and sheep. Then somewhere about the 11th century the Bantu started their long migration southwards and brought with them the knowledge of smelting of iron ore. One of their settlements was here in Johannesburg on the Melville Kopje at Emmarentia. These people were the first miners and metallurgists on the Witwatersrand and the beautifully preserved iron smelting furnace constructed nearly 1,000 years ago is a tribute to their technical ability. This ability to use iron to make better spears for hunting or to fashion hoes for cultivating the soil led to their establishment as a superior tribe. The earlier Bushmen were pushed back to the inhospitable swamps and deserts and the Hottentots fled to the south. The Bantu also knew the art of copper smelting. In the days of the Dutch East India Company, at the end of the seventeenth century, Bantu workers brought copper from the north-west Cape to Simon van der Stel, but it was another two hundred years before the white man turned this to advantage. Stories of the Bantu mining gold spurred the early European hunters to travel deeper into the heart of Africa in search of wealth, and we are told that Karel Kruger, in 1834 whilst leading an ivory hunting expedition, discovered gold on the Witwatersrand, and took samples to Cape Town; but when he returned with a larger expedition a few years later his party was attacked by Moselekatze's Matabele near Potchefstroom. Kruger was killed and only the legend survived. The real spur to mining in this country was the discovery of diamonds in Griqualand West in 1867. The field seemed fabulously rich and diggers flocked to the scene from the four corners of the earth. With them came Cecil Rhodes, Barnato, Beit and some of the finest mining and financial brains the country had yet seen. These giant entrepreneurs were not tempted by the small deposits of gold in the Barberton and Pilgrim's Rest areas when these were made a few years later but

A banquet, attended by 467 members and visitors, was held at the Wanderers Club, Johannesburg, at 8 p.m. on Friday, 21st March, 1969, to celebrate the 75th Anniversary of the founding of the Institute. Introduction of Dr Carel de Wet R. C. J. Goode (President) Dames en here: Ons het 'n aantal vooraanstaande gaste in ons midde vanaand en mnr Maxwell sal u later meer van hulle vertel. Dit is my aangename plig om u voor te stel aan sy Edele, die Minister van Mynwese, van Beplanning, en van Gesondheid, Dr de Wet en sy gade, mev de Wet. Sy Edele Dr de Wet het geen bekendstelling nodig nie-alhoewel hy ons minister vir slegs die afgelope twee jaar is, het hy reeds talle funksies van ons Mynbedryf bygewoon en het baie vriende gemaak onder ons. Hy het homself baie bemind onder ons gemaak toe hy Wes-Driefontein onlangs besoek het om hulle ondersteuning en aanmoediging aan te bied in hulle uur van nood. The Honourable Dr de Wet was born in the Free State. He is a grandson of that very famous general Christiaan de Wet, who caused so much pain to the British forces and for so many months so successfully eluded them in the Transvaal and Orange Free State. He was educated at both the Pretoria and Witwatersrand Universities. He first practised medicine at Boksburg and then moved to Vanderbijlpark, so you see he has an early association with gold mining on the Witwatersrand, and in moving to the Vereeniging-Vanderbijlpark district he became closely involved in our coal mining and metallurgical industries. South Africa's first steel was poured from a l0-ton open hearth furnace belonging to the Union Steel Corporation in Vereeniging in 1913. Dr de Wet has been mayor of Vanderbijlpark and for several years has been their member of parliament. More recently, the Honourable Dr de Wet has filled with great honour that most important office of Ambassador for the Republic of South Africa in London. At present he wears two hats, in that he is Minister of Planning and of Health, but more important is his cloak, that of Minister of Mines, which I trust offers him the greatest comfort. To fulfill these three arduous tasks must demand of him a terrific devotion to duty, and in doing this he carries on that loyal tradition of service to his fatherland so evident in his grandfather. Dames en here, dit is vir my 'n groot genoeë om Sy Edele Dr de Wette vra om 'n heildronk in te stel op die Instituut vir Mynwese en Metallurgie. Toast to the Institute of Mining and Metallurgy Dr the Honourable C. de Wet (Minister of Mines): Mr President, ladies and gentlemen, Mr President you have introduced me gracefully to this distinguished company and I am appreciative of your remarks. I am fully conscious of the responsibilities that devolve upon me as Minister of Mines in a country where mining makes so vital a contribution to economic progress and development and has, in fact, laid much of the foundation on which our present proud edifice is built. The achievements of the mining and metallurgical industry in its diversified activities arouse feelings equivalent to paternal pride, but let me speedily add that in considering any family relationship that may exist, the Minister of Mines should not be regarded in the role either of a fairy godmother or an indulgent father.

By D. N. Esfahani, K. Khazen, M. Mohammadi

Electrowinning is one of the nickel recovery processes from solutions obtained from the leaching of nickel sources. Every year significant amounts of nickel products are used in various industrial processes and daily life, such as catalysts or batteries, which are a valuable source of nickel for recovery. Nickel purity is also very important in the electrowinning process, because the amount of impurities in nickel such as sulphur, if greater than 100 ppm, make it unsuitable for use in catalysts and plating. Because sulfur is intrinsic to the sulphate electrowinning system, we needed to investigate parameters that can affect the quality and purity of nickel. In this regard, experiments were performed in static and circulating electrowinning processes. A monitoring and circulation system was designed and built to measure voltage, current and temperature as well as to circulate the solution in the system at a specified rate. It was then observed that nickel ion concentration, pH, using the circulation system and additives, were factors affecting the purity and quality of nickel, and in the best case the amount of sulphur in nickel was below 100 ppm. Keywords: Nickel, electrowinning, sulphur impurity

Jan 1, 2020

By J. -M. Milazzo, T. Wallmach, S. B. Blancher, A. Amalric

In a FeNi electric arc furnace, the physical properties of the slag (chemistry, viscosity, liquid/solid/gas ratio) are of crucial importance in controlling the efficiency of the process. In this paper, we studied the slag crystallised on the walls of a semi-industrial furnace (freeze-lining), the slag rising through the burden during foaming phenomena, and the casted slag. The freeze-lining is the layer of oxides that crystallises on the refractory wall of a furnace, protecting it from chemical and mechanical aggression. It records changes in furnace conditions (slag chemistry, temperature, oxygen fugacity), which makes it possible to observe the impact of these elements. In the high reduction test, the freezing lining is composed of magnesian olivine. Switching to a low reduction process increases the Fe content of the olivine and causes orthopyroxene to appear, making the freeze-lining mechanically and thermally weak. Thermal incidents in the furnace cause significant slag foaming. This foaming is produced by a massive crystallisation of the olivine (due to the drop in temperature), and inducing an exponential increase in viscosity, preventing the free circulation of gases. These foaming episodes are also recorded in the freeze lining and form layers rich in gas bubbles, and therefore mechanically fragile. The slag casted and cooled in a ladle allows the first steps of slag crystallisation to be studied. Olivine is the liquidus phase, with a magnesium-rich core and an iron-enriched rim, contemporaneous with the orthopyroxene phase. The habitus of these phases is very similar to that found in komatiites for the same minerals. FeNi slag is therefore an industrial analogue that is easy to study and compare to komatiites. Keywords: Pyrometallurgy, ferronickel, slag, freeze-lining, characterisation, olivine, mineralogy

Jan 1, 2020

By H. Jiang, W. Wang, Y. Zhao, Q. Jinpeng, C. Duan

Dry deep screening is an important method of classifying moist fine mineral. The rigid-flexible coupled elastic screening technology can simultaneously solve the problem of traditional screen surface plugging and the low service life of a screen surface in the process of deep screening. In this paper, two kinds of rigid-flexible coupled elastic screen surfaces were introduced. The structural characteristics of a screen surface were studied. The mechanism of a rigid flexible coupled elastic screen surface to overcome hole blockage was revealed. Finally, 3 mm and 6 mm screening experiments were carried out. When the external moisture content was below 12.79% for the 6 mm dry screening experiment of elastic rod screen surface, the screening efficiency was above 81%. When the external moisture content was below 11.31% for the 3 mm dry screening experiment of elastic screen surface based on ball hitting, the screening efficiency was above 83%. Keywords: Moist fine mineral, rigid-fexible coupled, elastic screening

Jan 1, 2020

By J. W. D. Groenewald, L. Auret, B. S. Lindner, E. C. Nienaber

Mineral processing plants have complicated control strategies, with different control layers, multiple interacting loops, and feedforward disturbance rejection. The complicated control strategies mean that oscillations can arise and propagate to multiple loops and degrade the control performance. Oscillation detection techniques, such as the spectral envelope method, can be applied to detect oscillations within an observation window. However, the start- and end-points of the oscillations within the observation window cannot be identified with current oscillation detection techniques. The start- and end-points would be useful to label the oscillatory intervals, and then to use these labels to identify process conditions associated with the oscillation. In this paper, a pattern recognition technique, Density-Based Spatial Clustering of Applications with Noise (DBSCAN), was used to label oscillation intervals. An oscillation diagnosis workflow combining spectral envelope and DBSCAN was demonstrated on an industrial case study of oscillations in a flotation circuit concentrate sump. The workflow successfully detected the oscillation, labelled the oscillatory intervals, and enabled accurate root cause analysis. The impact of time series features, namely the signal power ratio () and the oscillation frequency, on the performance and optimal parameter selection of DBSCAN was also investigated. Low oscillation frequencies and low s negatively affected the performance of DBSCAN. Additionally, the results indicated that higher oscillation frequency was related to higher optimal values for the lag parameter. Keywords: Oscillation diagnosis, process monitoring, data mining, clustering, flotation control

Jan 1, 2020

By I. Serepa, N. C. Steenkamp

Investigations were conducted to determine the condition and stability of the existing decline at amine in the Kalahari Manganese Field, Northern Cape Province, South Africa. During the inspection of the decline, voids were identified behind the concrete lining on the hangingwall and sidewalls over a total linear distance of 230 m. The voids did not provide confinement and, as a result, self-mining was occurring behind the lining. Water was flowing into the decline, over a total linear distance of 100 m, at areas where the decline intersected incompetent rock units, causing softening of the concrete lining and deterioration of the surrounding rock mass. Further damage to the concrete lining was caused by expansion and contraction of the wet red clay unit. Remedial work comprised void filling and water sealing to prevent further deterioration of the decline and ensure that it remained operable for the remainder of the life of mine. Void filling was accomplished by drilling rows of holes along the decline to access the voids and filling the voids with foam. This was followed by the sealing with polymer fluids. Telescopic pipes were also installed to allow water to drain off. A visual inspection was conducted and check-holes were drilled to assess the quality of the remedial work. The void filling material had penetrated cracks in the concrete lining, and areas where voids were intersected by check-holes were re-filled. Additional holes were drilled to re-seal areas that were still wet. The remedial work was completed successfully, as all voids were filled and stability achieved without compromising the concrete lining. The ingress of groundwater was also reduced to some residual dampness.

Mar 2, 2022

By B. Besa, S. Nalukui

Globally, the demand for mineral products is ever increasing. Extraction of these mineral resources results in the continuous production of a huge volume of waste material, including tailing dumps. The mass of tailings usually exceeds the actual resource and often contains hazardous contaminants. This study investigated the effects of tailings disposal on soil, water, and air quality in the Nampundwe area. Water, soil, and dust samples were collected from different locations in the surrounding communities. The constituents analysed in the samples included copper, cobalt, iron, sulfate, and silica. According to the results obtained, some seepages occurred from the tailings impoundment to the shallow aquifer in the area. However, the general water quality meets the Zambia Environmental Management Agency (ZEMA) statutory limits. Recorded concentrations of sulfate (1500 mg/l), copper (1.5 mg/l), cobalt (1.0 mg/l), iron (2.0 mg/l), and silica were between 0.003 mg/l and 705 mg/l, which is far below ZEMA’s statutory limit. Silica concentration was also evident in the air. The highest concentration recorded was 260 ppcc (particle per cubic centimeter) recorded in July 2019 from the northern direction of the tailings dam. The concentration was below the statutory limit of 350 ppcc. The topsoil from the northern part of the tailings recorded a silica dust concentration of 39.9 ppcc. Iron was evident in the underground soil with a concentration of 8.01 ppcc, cobalt 0.005 ppcc, copper 0.051 ppcc, while sulfate was recorded as 0.41 ppcc.

Oct 9, 2024

By M. Mpofu, G. Stenzel, F. Magweregwede, B. Maphalala, T. Kgarume

Surface coal operations in which mining activities are conducted above old underground workings experience hot holes after drilling. In a coal mine, hot holes are defined as shot holes, which after being drilled have an in-hole ambient temperature of 40°C or above or show a temperature increase of 3°C or more during monitoring. Hot holes and other cavities, such as cracks, pose health and safety risks to workers, such as exposure to hot air and high concentrations of noxious gases released from these holes. In addition, workers may be exposed to premature detonation of explosives caused by in-hole temperature increases and chemical reactions. To this end, Coaltech Research Association commissioned a project to develop a Best Practice Guideline for the management of hot holes. This paper is a compilation of the activities conducted in the development of the Best Practice Guideline between 2021 and 2022. The activities included a review of standard operating procedures and hot-hole temperature-measuring and -monitoring devices, and the assessment of current hot-hole procedures at selected mines. The results indicated that management of hot holes requires a focus on pre-emptive risk assessment of mining blocks, identification of hot holes using the correct temperature-measuring devices, and continuous monitoring of hot holes from the time of drilling until just before blasting. Hot-hole management accessories, such as polyvinyl chloride sleeves, were found to be effective in insulating the hot-hole emulsion from the rock mass temperature, thus preventing the potential for premature detonation.

Sep 9, 2024

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