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By T. Nesane, S. S. Mnyakeni-Moleele, L. C. Murulana

The effectiveness of two synthesized ionic liquids, 1-(benzyloxy)-1-oxopropan-2-aminium 4-methylbenzenesulfonate (1-BOPAMS) and 4-(benzyloxy)-4-oxobutan-1-aminium 4-methylbenzenesulfonate (4-BOBAMS), were evaluated for mild steel corrosion inhibition in 1.0 M hydro-chloric acid solution, using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), and gravimetric techniques. Organic moieties responsible for the adsorption process on mild steel surface were investigated using Fourier transform infrared spectroscopy (FTIR). Gravimetric analysis revealed that the inhibition efficiency of 1-BOPAMS and 4-BOBAMS increased with concentration, with maximum inhibition values of 90.32% and 97.91%, respectively, at the highest concentration of the inhibitors. Gibbs free energy (ΔG°ads) values indicated a strong interaction between the mild steel surface and the molecules of the ionic liquids, and that the adsorption process was spontaneous. These values also show that the inhibitive nature of ionic liquids against mild steel corrosion is caused by a mixedtype of adsorption film formed on the steel surface. The Langmuir adsorption isotherm was used to describe the adsorption of ionic liquid molecules onto the mild steel surface. Polarization curves showed that 1-BOPAMS and 4-BOBAMS have a similar effect on both the anodic and cathodic half-reactions, indicating that they prevent the dissolution of mild steel through both physical and chemical process. Nyquist plots were defined by incomplete semicircle capacitive loops, showing that the charge transfer mechanism controls the corrosion of mild steel in acidic solution.

Apr 1, 2021

1. Book reviews Quantitative texture analysis, edited by H. ,}. Bunge and C. Esling. Deutsche Gesellschaft fur Metallkunde, 1982. 551 pp. Reviewer: L. 1\'1.Matthews Boundary element methods in solid mechanics by S. L. Crouch and A. M. Starfield. Reviewer: J. A. C. Diering World mineral statistics 1976-1980. Produdion,' exports,' imports, by Institute of Geological Sciences. London, Her Majesty's Stationery Office, 1983. £18.00 Reviewer: R. P. King 2. New publications Canadian mines,. perspective from 1982. Mineral Bulletin MR 197. Supply and Services Canada, Hull, Quebec K1A 059, Canada. Copper' s changing cost structure, by Commodities Research Unit Ltd (31 Mount Pleasant, London, WClX OAD, England). Petrology of metamorphic rocks, by M. Suk. New York, Elsevier, 1983. 320 pp. U.S. $68.00. Applied geomorphology, by H. Th. Verstappen. New York, Elsevier, 1983.442 pp. U.S.$95.75. Tin and its uses, no. 137, by the International Tin Research Institute. Greenford, the Institute (Fraser Road, Greenford, Middlesex UB6 7AQ, England), 1983. 3. New journals Mining Science and Technology, edited by C. 0, Brawner and B. N. Whittaker, is to be published quarterly in one volume per year by Elsevier. Aluminium, published monthly by Aluminium -Verlag GmbH, P.O. Box 1207, D-4oo0 Diisseldorf 1, F.R. Germany. DM 690.00 per annum. Rock mechanics The South African Institute of Mining and Metallurgy is to hold two schools on 'Rock Mechanics in Mine Management' at the University of the Witwatersrand, Johannesburg, from 23rd to 27th January, 1984, and from 30th January to 3rd February, 1984. The Federation of Societies of Professional Engineers The Federation of Societies of Professional Engineers (FSPE) has been a member of the World Federation of Engineering Organisations (W FEO) for many years and has regularly sent delegates to the biennial conference of that organisation. Second progress report by ASRET The Professional Engineers Joint Council was estabislhed in 1960 and initially its main fWlction was to represent the interests of engineers. Explosives technology The Center for Explosives Technology Research (CETR) has been established at the New Mexico Institute of Mining and Technology (Tech) in Socorro, New Mexico. International Tunnelling Association A conference entitled 'Ita Tunnels 1984' will be held in Caracas, Venezuela, from 2nd to 7th June, 1984. Automation The IFAC Symposium on Automation for Mineral Resource Development is to he held in Brisbane (Australia) from 9th to nth July, 1985.

Jan 1, 1983

By A. Smith

After the introduction of mechanized bord-and-pillar development at Dumacol in 1958, pillars were being developed at a much faster rate than they could be extracted by hand loading methods. Efforts were therefore made to increase the rate of pillar extraction by mechanization. Following two partially successful mechanized stooping trials in 1964 and 1971, it was decided that mechanized pillar extraction with 1 m3 cable-reel front-end loaders should be introduced. The first section to employ the new equipment started production in May 1979, and the mine now has four mechanized pillarextraction sections in operation. Considerable improvements in production, productivity, safety, and percentage extraction have been achieved.

Jan 1, 1985

By M. Klapwijk

Ancient Metallurgy - In addition to the preceding three papers, the following three contributions were received for publication 1. An analysis of Bantu-made iron implements from the Letaba district M. KLAPWIJK INTRODUCTION It has often been stated that it is hardly possible in South Africa to classify Bantumade iron hoes according to their places of origin and manufacture. It is well known that these hoes were used for barter, and as currency in the purchase of livestock or the payment of lobolo, although reports of the value of the hoes differ widely. The difficulty in their classification has arisen from their distribution over a very wide area.

Jan 1, 1974

The February General Meeting of the Institute was held in Kelvin House, Johannesburg, on 19th February, 1969 at 4.30 p.m. Mr R. C. J. Goode (President) was in the Chair. There were also present forty-six Members, including Messrs H. E. Cross, A. R. C. Fowler, P. Lambooy, D. G. Maxwell, Dr J. T. McIntyre, Messrs J. A. Nixon, V. C. Robinson and P. W. J. van Rensburg (Council Members), Messrs G. Abdinor, H. F. Allan, R. E. Barnes, M. M. Bayley, J. K. Boyd, R. R. M. Cousens, R. E. F. Cowley, D. Savile Davis, H. J. Davisson, C. T. Fenton, J. Fergusson, J. Fritz, M. L. Fitzgerald, J. M. Gosnell, J. C. Hall, S. A. Hancox, D. M. Jamieson, Dr D. G. Krige, Messrs J. E. V. Leeuwen, A. Louw, C. F. Louw, B. H. L. Leach, R. B. MacGillivray, C. S. McPhail, E. Margo, G. G. Nicolson, E. Pavitt, M. P. Pearse, F. O. Read, Dr M. D. G. Salamon, Dr H. S. Sichel, Messrs D. Storrar, S. G. Taussig, A. H. Taute, E. B. Viljoen and P. A. von Wielligh. Sixteen Associate Members, including Messrs S. T. Baron, W. M. Fitzpatrick, M. R. Fuller-Good, P. R. Garcia, H. G. Gericke, P. D. Hatfield, R. Hemp, G. S. Lee, Miss V. E. Marting, Messrs A. H. Munro, R. C. Power, O. F. Rheeder, G. C. Thompson and N. Zolezzi. Two Graduates, Messrs D. Bosley and J. C. Sutherland. Three Affiliates, Messrs R. K. Briggs, A. B. Cook and G. M. Thain. One Student, Mr P. W. Henrard. Twenty-three Visitors, including Messrs N. J. W. Bell, R. G. Bushell, A. Bryan, J. F. Cillie, C. M. de Beer, Dr F. H. Deist, Messrs D. S. Drake, P. G. du Plessis, R. W. Hodgson, D. M. Hawkins, S. C. H. Kearns, M. D. Labuschagne, L. Munro,R. Murchison and L. Robinson. Secretary, Mr D. C. Visser. Total present: Ninety-two. OBITUARIES The President: "It is my sad duty to announce the death of the following members of the Institute. Edward Frank Jud Bulman, Life Member, who joined the Institute in 1931 and passed away on 7th November, 1968. Elmar Fenton Chapin, Member, who joined the Institute in 1941 and passed away on 17th November, 1968. Solly Rabinowitz Rabson, Member, who joined the Institute in 1944 and passed away on 13th February, 1969. Mr. Rabson was the holder of two certificates of merit for papers presented to the Institute.

Book review Proceedings of the Symposium on Mining Methods. London, Institution of Mining and Metallurgy, 1974. 160 pp. The Symposium was held from 30th October to 1st November, 1974, and the papers include an interesting range of subjects in coal-mining operations, covering the improvements achieved to date, current practice, and required development for the future. Salamon, M.D.G., and Oravecz, K. 1. Rock Mechanics in Coal Mining. 119 pp. NIM reports Report no. 1822 Stability constants and linear free-energy relations for the platimtm-group metals. (22nd Oct., 1976). Report no. 1852 A revised method for the dissolution of platiniferous materials by the sealed-tube technique. (18th Oct., 1976). Report no. 1828 y-picoline adducts of the nickel, copper, and zinc chelates of 2-thenoyltrifluoroacetone. (26th Nov., 1976) Report no. 1847 A pilot-plant investigation of a kinetic model for flotation.(19th Nov., 1976)

Jan 2, 1977

1. Book reviews Perspectives in metallurgical development. London, The Metals Society. 338 pp. £29. Reviewer: John V. Bee Mechanics of oil shale, edited by K.P. Chong and J.W. Smith. London, Elsevier Applied Science Publishers Ltd, 1984. 603 pp. £75. Reviewer: R.W.O. Kersten 2. Recent publications CANADIAN MINERAL POLICY SECTOR. Metallurgical works in Canada. Primary iron and steel 1984. Mineral Bulletin MR 203. Ottawa, Canadian Government Publishing Centre, Supply and Services, 1985. $6.00. Tin and its uses no. 143. Greenford (England), International Tin Research Institute, 1985. Mining 1985, edited by Diana Russell. Harlow England), Longman Group Ltd, 1985. 540 pp. £46. The following books are available from CRC Press, Inc., 2000 Corporate Boulevard N.W., Boca Raton, Florida 33431, U.S.A. Inorganic ion exchange materials, edited by A. Clearfield. 304 pp. $100. Polyurethane foam sorbents in separation science, by T. Braun. $80. Advanced particulate morphology: theory and practice, by J.K. Beddow and T.P. Melloy. 208 pp. $79. CRC handbook of atomic absorption analysis, edited by A. Varma. 2 vols: vol. I $114, vol 11 $102. CRC handbooks of inorganic elecrochemistry, edited byL. Meites, P. Zuman, E.B. Rupp, andA. Narayanan. 3. Mintek reports Report M169 The preparation of three South African coals for as reference materials. Report M190 The preparation and certification of a South African phosphate concentrate for use as a reference material. Report M191 The agglomeration of fine material for bacterial heap leaching. Report M197 A computer programme to monitor the performance of an X-ray-fluorescence spectrometer. Metallurgical award The 1984 Acta Metallurgica Gold Medal has been awarded to Professor John W. Christian of Oxford University. The medal is an international award that was established in 1974 to recognize outstanding ability and leadership in materials research. Proterozoic volcanic suites An international symposium will be held at the British Geological Survey, Keyworth, Nottingham, U.K., from 2nd to 5th April, 1986. Entitled 'Geochemistry and Mineralisation of Proterozoic Volcanic Suites', this special meeting of the Geological Society will discuss the geochemical evidence for the nature of volcanism during the Proterozoic. Powder metallurgy Every second year the International Powder Metallurgy Conference, the world's leading event in powder metallurgy, is organized and held alternately in North America and Eruope.

Jan 1, 1985

By D. A. Singer, J. C. Griffiths

"One of the most useful approaches to a complex problem is to model the system which gives rise to the problem and to perform simulations through the model to find appropriate solutions. The Engel Model may be used as such a simulator to investigate the problem of the exploration for natural resources.The Engel Model is based on a two-stage search procedure in which a known area (A) which contains m prizes is subjected to search by n coverings. During the first-stage search the sensor system records signals which may be a response from prizes (that is, true signals) or may be false. Signals tend to cluster around a prize and a cluster size consists of s signals. If a circle of radius R is drawn around each signal some will overlap and the overlap from s signals contains a prize. The cost of a single covering in which each point of the area comes under observation once, is designated E1. Second-stage detailed search is expensive and is confined to areas of overlap of s circles; it leads to the location of prizes. Second-stage search of the whole area costs Ea units. The expected value, V, of a prize is known and its development cost is E3 units.The sensor system characteristics are defined by the circle of radius R around a signal, which should be small compared with the total area A and enters the model as a parameter a x R2/A. The probability of a false signal during a single covering of a circle of radius I is a known constant, A.This model was applied to the search for uranium ore bodies using two different types of occurrence. In the first, the Wyoming Basin type, the area is relatively large (A = 1 496 square miles) and a few (m = 4) large prizes occur (expected value V = $30 million). In the second area, which represents the Ambrosia Lake region of New Mexico, the area is smaller (A = 212 square miles) and contains many (m = 200) smaller prizes (expectedvalue of a prize V,$2 million). The three costs, E1, E2, E3, are adjusted to the different circumstances in the two areas.Simulations were performed using n = 1 to 40 coverings with cluster sizes s = 0 to 19; the radius R was varied from 0.52 to 3 miles (and, therefore, a = 0.002 to 0.133 0, respectively, dependent on the area of interest). The value of A was varied from 0.01 to 0.10.Profitable programs were found over a wide range of the parameters; the two areas required different strategies to achieve maximum profit. In the Ambrosia Lake region a few passes (n = 4 to 6) with small cluster sizes (s = 2 to 6) are more profitable, whereas in the Wyoming Basin region a large number of passes (n = 35 to 40) and cluster sizes of s = 5 to 10 are most profitable.As pointed out by Allais (1957) the larger prizes are the most important in deciding the successful outcomes of exploration programs, and the profit margin in the search for a few large prizes is sufficient to yield success over a wide range of programs. Such programs require very large investments if they are to be successful.To refine the Engel Simulator as a decision-maker in selecting the most profitable exploration programs it is necessary to obtain firm estimates of the sensor system characteristics, that is, of R, a and ? (lambda)."

Jan 1, 2014

By G. M. J. van Heerden

Paper written on project work carried out in partial fulfilment of B. Eng (Mining Engineering) degree The Union Section of Anglo Platinum is situated ±18 km west of the town of Northam on the north-western rim of the Bushveld Igneous Complex. Both the Merensky and UG2 reefs are mined. Support of the Merensky stoping areas with rock bolts is specifically problematic due to the stoping width restrictions varying around 90 cm. The installation equipment of in-stope rock bolts and the effectiveness thereof in the Merensky stoping areas was critically evaluated. In order to do this a background research on the need for better on-the-face support had to be conducted. The need for improving the rock bolt drilling and the equipment had to be investigated and the financial implications and justifications for the improved equipment examined. To conduct the search an overall study was done on the rockfalls and safety aspects throughout the platinum industry in South Africa and specifically Union Section. It was found that most of the rock falls in the Merensky stoping areas of which ± 70% are less than 1.2 m in thickness generally occurs within 4 m from the face and causes ± 60% of the in-stope injuries. Serious shortcomings had been identified with respect to the airleg, rock drill machine and the drill steels used in the drilling of the rock bolt holes. Through experimentation, using a testing frame built for this purpose on surface and with the co-operation of mine staff and suppliers, a number of possible modifications were identified and tested. This resulted in the final product with which it was possible to drill a 1.2 m hole in the hangingwall of the stopes ranging with an angle to the hanging from 90° for a 90 cm stoping width and 67° for a 80 cm stoping width. It is confidently concluded that this system will effectively improve the total face support and result in a substantial reduction of rock falls and consequently the occurrence of injuries and fatalities in the Merensky stoping areas. The installation of rock bolts on the face with the modified drilling equipment will increase the direct support, but the system has a potential of a substantial reduction in the profile stick support density and an increase in productivity in the stoping areas due to fewer occurrences of rock falls. It was finally concluded that effective modifications to the drilling equipment for rock bolt in-hole drilling could be made and the installation thereof in the stope face is adequately justified.

Jan 1, 2002

By P. J. Bartlett, H. A. D. Kirsten

A two-dimensional numerical scheme for the simulation of the plastic stress-strain properties of rock, and the various components of rock reinforcement and shotcrete, was used to rigorously determine the characteristics of tunnel support under squeezing conditions. D-shaped tunnels varying in size from 2,8 to 6,5 m in height and width were considered. The four main mining stages in the BAS block cave on Premier Mine were simulated as alternative sets of field stresses. The rock reinforcement comprised 1,8 m long fully grouted rockbolts and 6,0 m long fully grouted cable anchors at various spacings, and of various tensile and bond strengths. Various thicknesses of shotcrete and footwall support configurations were also considered. It was found that shotcrete and rock reinforcement, owing to inherent differences in stiffness, do not function in unison. As monolithic application, shotcrete has an overriding avidity for the imposed loading and destructs itself unless of extraordinary thickness. Under squeezing conditions, it accordingly supports the excavation surface while the rock reinforcement contains on-going convergence. The loads in the various support components can be determined only by simulation of the shotcrete as a stress-relieved medium to represent its broken condition in the field. The loads in the rock reinforcement vary around a tunnel and are the largest in the sidewalls. The loads increase with an increase in tunnel dimensions, the increase in load in the sidewall due to an increase in height being larger than that in the hanging- and footwalls due to an increase in width. Depending on the strength of the rock, the loads in the rock reinforcement become prohibitively large beyond a certain size of tunnel. The reinforcement of footwall rock can be omitted without adversely affecting that in other walls, provided the tensile and bond strengths of the reinforcement are not limited. The resulting footwall heave may, however, result in undermining of the reinforcement in the adjoining walls. A relative depth of anchor of 1,37 provides adequate bond strength in the larger sizes of tunnel, whereas, in smaller tunnels, anchor length is determined by the allowable convergence. The lack of fun column grouting adversely affects the efficiency of rock reinforcement to a major extent. The loads in rock reinforcement are very sensitive to the strength of the rock. Owing to a lack in refinement and calculational rigour, empirical classification systems are an inappropriate means for the design of tunnel support in squeezing conditions and, as a result, grossly unclear-estimate the support requirements.

Jan 1, 1992

Council and Standing Committees, 1979-1980 President: D. A. Viljoen. Senior Vice-President: Dr P. R. Jochens. Junior Vice-President: G. Y. Nisbet. Honorary Treasurer: Dr D. G. Krige. Immediate Past President: Dr M. G. Atmore. Members of Council: J. D. Austin, A. N. Brown, J. A. Cruise, C. E. Fivaz, J. S. Freer, P. N. Harris, H. E. James, Dr R. P. King, Prof. F. Q. P. Leiding, Dr B. K. Love¬day, D. G. Malan, C. S. Macphail, J. C. Mostert, H. G. M. Rose, G. C. Thompson, R. A. von Maltitz, Dr H. Wagner. Past Presidents Serving on Council: R. J. Adamson, H. Britten, J. K. E. Douglas, Prof. D. D. Howat, Dr J. P. Hugo, D. G. Maxwell, Prof. R. P. Plowman, Dr R. E. Robinson, Dr M. D. G. Salamon, P. W. J. van Rensburg, P. A. von Wielligh. Chairman, Witbank-Middelburg Branch: R. B. Smith. Chairman, Orange Free State-Klerksdorp Branch: W. C. Mather. Materials Engineering Division, Chairman: Dr J. P. Hugo. Secretary: G. Pienaar. Standing Committee Chairmen: Membership, G. Y. Nisbet; Technical Programme Metallurgy, H. E. James, (Prof. R. P. King) ; Technical Programme Mining, H. G. M. Rose; Vacation School Metallurgy, J. C. Mos¬tert; Vacation School Mining, J. D. Austin; Awards, Dr M. G. Atmore ; Excursions, A. N. Brown ; Adjudications, Dr M. G. Atmore ; Constitution, Rules, and Policy, Dr M. G. Atmore ; Monograph Series, Dr M. G. Atmore ; Training and Career Guidance, P. A. von Wielligh (D. G. Malan) ; National Phoenix Committee, Dr R. E. Robin¬son; 1982 Council of Mining and Metallurgical Congress, Dr M. G. Atmore ; Mines and Works, Dr M. G. Atmore.

Jan 1, 1980

1. Mining directory The mining directory, 1990. Mines and mining equipment companies worldwide. Don Nelson Publications Limited (P.O. Box 193, Barnet, Herts EN4 BLP, England).2. Mintek reports The following reports are available from Mintek, Private Bag X3015, Randburg, 2125 South Africa. They are available at R25 (plus R3,25 GST) per copy to South African addressees, and US$25 per copy (including airmail postage) to addressees elsewhere. There is also an annual-subscription scheme for reports - R400 locally (plus R52 GST) and US$400 (including airmail postage) abroad. The subscription covers al the unrestricted reports published between 1st April and 31st March of successive years, which usualy amount to between 20 and 30. Report M392 Computer programs for optimization by the modified simplex method, by G.L. Moore. Sep. 1989. 25 pp. R25 + R3,25 GST in South Africa; US $25 elsewhere. Report M393 The preparation and certification of fourteen South African silicate rocks for use as reference materials, by E.J. Ring. Sep. 1989.21 pp. R25 + R3,25 GST in South Africa; US $25 elsewhere. Report M395 The separation of trace elements in high-purity rhodium and iridium materials, by R.V.D. Robet and S.M. Graham. Nov. 1989. 10 pp. R25 + R3,25 GST in South Africa; US $25 elsewhere. 3. Publications from Trans Tech The publications listed in this section are available at the prices given from Trans Tech Publications, P .0. Box 1254, D-3392 Clausthal-Zelerfeld, West Germany. Handling of bulk solids. Theory and practice, by P.A. Shamlou. 1988. 200 pp., US$ 59.50. Acoustic emission lmicroseismic activity in geologic structures and materials, by H.R. Hardy and F.W'. Leighton. Vol. I: 1977, 490 pp., US$45.00. Vol. 11: 1980, 500 pp., US$45.00. Vol. Il: 1983, 680pp., US$6O.00. Vol. IV: 1989, 720pp., US$ 75.00. Open pit mine design models. An introduction with FORTRANI77 programs, by E. Alaphia Wright. Early 1990, approx. 200pp., US$75.00. Bucket wheel excavator, by W. Durst and W. Vogt. 988, 450pp., US$118.00. Continuois-surjace mining, by T.S. Golosinski and F.G. Boehm (eds.). 1987, 720pp., US$128.00. Mining-science and technology. 1987, 1430pages, US$ 118.00. Practical handbook for underground rock mechanics, by T.R. Stacey and C.H. Page. 1986, 150pp., US$ 38.00. Professional users handbook for rock bolting, by B. Stilborg. 1986, 150pp., US$38.00. The lighting of underground mines, by D.A. Troter. 1982, 220pp., US$48.00. Elements of hydraulic coal mine design, by M.L. Jeremic. 1982, 16Opp., US$38.00. Continuum theory of rock mechanics, by Cs. Assonyi and R. Richter. 1979, 365 pp., US$ 58.00. Shear and bond in reinforced concrete, by G. Florin.1980, 86 pp., US$ 24.00. Theory and design of surface structures: slabs and plates, by G. Florin. 1980, 222 pp., US$ 24.00. Mineral processing laboratory manual, by A.-Z. Abouzeid. January 1990, approx. 200pp., US$48.00. Weighing and proportioning of bulk solids, by Hendrik Colijn. 2nd ed. 1983, 4OOpp., US$60.00. Solid-liquid flow. Slurry pipeline transportation, E.J. Wasp et al. 1977, 240pp. US$ 58.00. Optimum pipe size selection, by C.B. Nolte. 1978, 304 pp., US$ 60.00.Field instrumentation in geotechnical engineering, T.H. Hanna. 1985, 854pp., US$98.00. The 1990 yearbook and directory. Powder and bulk solids handling and processing. 1989/90, approx. 300 pp., US$ 124.00.

Jan 1, 1990

Council and Standing Committees, 1977-1978 President: P. A. von Wielligh. Vice-Presidents: Dr M. G. Atmore and D. A. Viljoen. Honorary Treasurer: J. K. E. Douglas. Immediate Past President, Dr M. D. G. Salamon. Members of Council: J. D. Austin, A. N. Brown, A. A. Hazell, Dr P. R. Jochens, Prof. R. P. King, Dr D. G. Krige, Prof. F. Q. P. Leiding, D. G. Malan, J. C. Mostert, H. G. M. Rose, W. T. Ruhmer, A. A. Sealey, R. A. von Maltitz. Chairman, Witbank-Middelburg Branch: T. S. Wilmot. Chairman, Orange Free State-Klerksdorp Branch: A. N. Shand. Past Presidents Serving on Council: R. J. Adamson, H. Britten, J. K. E. Douglas, Prof. D. D. Howat, Dr J. P. Hugo, D. G. Maxwell, Prof. R. P. Plowman, Dr R. E. Robinson, P. W. J. van Rensburg. Standing Committee Chairmen: Membership, D. A. Vil¬joen; Technical Programme - Metallurgy, Dr P. R. Jochens ; Technical Programme - Mining, Dr D. K. Krige ; Vacation School - Metallurgy, Prof. R. P. King ; Vacation School - Mining, Dr M. D. G. Salamon; Awards, Dr M. D. G. Salamon; Excursions, Dr M. G. Atmore; Adjudication, Dr M. D. G. Salamon; Consti¬tution, Rules, and Policy, Dr M. D. G. Salamon; Mines and Works, P. A. von Wielligh ; Education, Dr M. D. G. Salamon; Monograph Series, Dr R. E. Robinson; Phoenix National Committee, Dr R. E. Robinson ; Pyrometallurgical Discussion Group Convenor, Dr J. B. See/Dr D. I. Ossin.

Jan 1, 1979

By A. M. Neale

Kriel Colliery has experienced some sub-standard blast results on the overburden. Blast results are considered poor when the fragmentation is too big, back break into the new highwall, capping is experienced and/or excess overburden material is thrown into the void. Poor blasting leads to lower productivity, equipment breakdowns, and poor drilling and blasting results on the adjacent blast, contamination of coal or loss of coal. A simulation was developed in Microsoft Excel to model blasting results while changing various parameters. From the simulation results, it could be seen that a change of blast design could be beneficial. As an example, smaller drilling patterns were simulated (10 m x10 m to 8 m x8 m, and 8 m x8 m to 7 m x7 m in Pit 5 and Pit 6 respectively) in combination with changes in explosives (P700 emulsion vs. ANFO) and drill bit diameter (311 mm vs. 251 mm). The results show that each of the options has a specific scenario that will be most beneficial to the mine. These results are quite specific and subject to variable inputs. The purpose of the example is to demonstrate how the simulation can be used as a tool to asses blast design variations.

Jan 1, 2010

Professor R. P. Plewman graduated with a B.Sc. in mining engineering from the University of the Witwatersrand in 1943, after which he had two years of military service. Mr P. W. J. van Rensburg attended St Andrew's College in Grahamstown before proceeding to the University of the Witwatersrand, where he obtained a B.Sc. (Eng.) degree cum laude in mining and metal. lurgy at the end of 1942 and was awarded the Chamber of Mines Scholarship and Gold Medal. Dr M. G. Atmore, Deputy Technical Director of the Anglo American Corporation of South Mrica, is also Manpower and Education Adviser to the Chamber of Mines of South Mrica and a Visiting Professor at the Imperial College of Science and Technology, London. Mr D. A. Vi1joen attended Queen's College, Queenstown, and then Rhodes University, where he gained a diploma in chemistry and a B. Comm. degree. Mr B. E. Protheroe, C.Eng., obtained a degree in Physical Metallurgy at University College, Cardiff, and an M.sc. in corrosion science from Swansea University. Mr N. J. Devine holds a B.Sc. in Metallurgical Engineering and a G.DE Mining Engineering, both from the University of the Witwatersrand. Dr Oskar Steffen graduated as a civil engineer at the University of the Witwatersrand in 1961, and obtained his master's degree in 1963.

Jan 1, 1984

A Special General Meeting of the Institute was held in Kelvin House, Johannesburg on Wednesday, 29th September, 1971. The President, Prof. D. D. Howat opened the meeting at 9.55 a.m. The President read the notice of meeting which was as follows: "In order to bring industry into closer liaison with the work of your Institute and to place the Institute's finances on a sound basis your Council recommends that companies be admitted to membership of the Institute under clause 2.6 of the Constitution, that is, as Non-Corporate members. The designation for this class of member will be that of "Company Affiliate". 2 Membership: This clause to be amended as follows:- 2.6 "Non-Corporate members shall comprise the grades of:- Company Affiliate Honorary Fellow Graduate Associate Student" 2.6.1 This clause to be added:- "Companies involved in or associated with the mining or metallurgical industries are eligible to become company affiliates" 2.14 Add:- "A special certificate shall be issued to all company affiliates". After giving the background to the recommendation made by Council the President asked for a proposer and seconder for the resolution. Mr J. K. E. Douglas proposed and Mr D. G. Maxwell seconded the resolution. The meeting agreed that the constitution be amended as proposed. The meeting closed as 10.05 a.m.

By W. Wilmans

Electrokinetic dewatering of kimberlite slime under constant direct curents of 0,5 to 2 A and dewatering under constant applied potentia Is of 16,5 to 46,5 V are considered. The combined efects of electrophoresis and the addition of 8,3 x 10-3 M Mg2+ ions on the one hand, and 1 to 10 p.p.m. of the anionic polyacrylamide flocculant Praestol 2935 on the other, were investigated in a 3-litre Perspex electrophoretic cel. .The electro-osmotic dewatering experiments were conducted in a 3-litre Perspex electro-osmotic cel at various electrode spacings, as well as with a moving anode (top electrode). During electrophoretic dewatering, the zeta potential of the kimberlite particles did not change significantly, whereas the pH and temperature showed marked increases with time. The addition of Praestol 2935 enhanced the setling of the sludge bed owing to the additional effect of flocculation. The addition of electrolyte Mg (CIO4)2 retarded the separation process, partly as a result of gel formation in the slurry. During the electro-osmotic experiments, the rate of dewatering was found to be approximately proportional to the applied constant direct current, and to be independent of the electrode spacing. In general, electro-osmotic dewatering seemed to be more energy-efficient than electrophoretic dewatering.

Jan 1, 1987

By K. Hodgson, J. P. M. Hojem, N. G. W. Cook

Already about one-third of South Africa's coal is mined at depths exceeding 100 metres. Almost all this mining is done by the bord and pillar method. Conventional design procedures call for ever larger pillars as depths of workings increase, resulting in the loss of large amounts of coal and reductions in productivity. Barrier pillars are in general use to ensure against large collapses. The presence of these strong pillars would allow a more efficient design of the bord and pillar layout to yield improved extraction ratios by using smaller, yielding, pillars between the bords. Knowledge of the complete load- displacement curves for such pillars is a prerequisite for the design of such a system. A 100-MN, stiff jacking system for measuring the complete load-displacement curves of pillars with cross-sections of up to 2 m X 2 m is described. The jacks are installed in a slot cut across the central plane of symmetry of a pillar, thereby ensuring that the stress distribution in the pillar during a test, especially at its contacts with the roof and floor, is identical to that caused in a similar pillar by convergence across the seam. Preliminary results in the form of complete load-displacement curves for test pillars of about 1.5 metre square section are given.

Council for 1999/2000 President J.R. Dixon President Elect M.H. Rogers Vice Presidents Senior Dr L.A. Cramer Junior A.A.B. Douglas Immediate Past President R.P. Mohring Honorary Treasurer J.A. Cruise Members of Council B.C. Alberts Dr N.A. Barcza N.J. Barkhuysen R.D. Beck M.J.P. Bierman Prof. A.N. Brown D. Cockcroft Dr M.B. Cortie Dr L.A. Cramer J.A. Cruise E.G. de Villiers J.R. Dixon A.A.B. Douglas F.M.G. Egerton J.P.W. Fisher C.E. Fivaz K.J.R. Ford Prof. G.A. Fourie R. Graham Dr R.G. Gürtunca Dr R.V.R. Handfield-Jones* M.C. Harris J.P. Hoffman H.E. James P.J. Knottenbelt R.P. Mohring H.G. Mosenthal G.Y. Nisbet N.M. O'Brien R.G.B. Pickering Prof. R.P. Plewman S.J. Ramokgopa Prof. R.E. Robinson M.H. Rogers D.A.J. Ross-Watt Prof. R.F. Sandenbergh Dr H. Scott-Russell C.B. Sheppard D.A.A. Smith Dr T.R. Stacey Dr O.K.H. Steffen D.J. van Niekerk J.C. Viljoen J.N. Wallington

Jan 1, 1999

By J. H. Viljoen, C. H. Graan, N. B. Strydom, J. S. Greyson

M J Martinson (Fellow) There is everywhere a lamentable dearth of quantitative information on occupational factors affecting the health and safety of mineworkers, and as the authors point out in their introduction underground lighting is one of the factors which has received little attention in South Africa prior to this welcome paper. Since the authors are to some extent pioneering, it is perhaps inevitable that the paper should raise more questions than it answers, but nevertheless it provides a provisional yardstick against which the need for, and success of, remedial action may be judged. Before commenting in detail on a few aspects of the paper it may be worthwhile to summarize the statutory provisions relating to underground lighting, contained in Chapter 15 of the Regulations promulgated in terms of the Mines and Works Act 27 of 1956. Chapter 15 is entitled `Lighting, Safety Lamps and Contraband', but in the context of the present paper only four simple regulations need be noted: firstly, no person shall work or travel in an unilluminated part of a mine unless he carries a light ; secondly, adequate stationary lights shall be provided at stations and certain other localities in shafts, winzes and places used for winding; thirdly, mechanically propelled conveyances shall be provided with an effective bright light shining in the direction of travel; and fourthly, moving machinery to which personnel have access shall be illuminated so as to be clearly visible. In all four regulations the standard of lighting to be provided is wholly subjective, and under these circumstances the wide inter- and intra-mine variations in light intensity disclosed by the study are hardly unexpected. Nevertheless the data presented in the authors' Table I raise three points (1) Is there any evidence that the 19 mines visited during the survey are representative of the 45-50 large gold mines in South Africa, or that the shafts selected are representative of the respective mines? Mine managers would scarcely be human were they not to offer better lit working places for the survey; perhaps the use of a scaling factor (e.g. tonnes or transit mineworkers per shift, kilowatts, etc.) for each working place might have helped to put the figures in perspective. (2) Looking at two of the more numerous - and probably important - of the ten working places included in the survey, i.e. stations and tips, one is struck by the marked. skewness of both intensity distributions (with higher frequencies at the lower intensities) and the abrupt cut-off in both cases just short of pitch darkness. Thus, of the 45 meaned readings recorded at 26 tips no less than 19 fall in the lowest range of 0,1-0,9 1m/ft2, with but one tip in total darkness; of 46 readings on 26 stations, 7 fall in the lowest range and none is in total dark-'1 ness. Although a light with an intensity in the range 0,1-0,9 1m/ft2 may satisfy the regulations, it is certainly arguable that in some situations it may be safer to have no light at all. (3) In view of the skewness referred to above, one wonders how meaningful are the `total average light intensities for (the gold mining) industry' quoted in Table I, which the authors compare with illumina¬tion levels found in other countries. Looking at tips again, one notes that 34 out of 45 meaned intensity readings fall below the `total average' for tips, and only 10 exceed it. From this it may be concluded that a few well-lit working places included in a `total average' may conceal a plethora in Stygian gloom. In their discussion the authors make fleeting reference to the effect of underground lighting on productivity and accident rates, without however quoting any South African experience in this regard. Intuitively it seems highly likely that better lighting (in the widest sense) would improve productivity and reduce accidents, and of course it is in these areas that the mining industry might seek economic justification for providing better lighting. It is all the more regrettable therefore that these factors were not studied simultaneously with the present investigation, especially at the Psychological Division of the Human Sciences Laboratory has recently published a study on underground accidents in the gold mining industry without making any reference whatsoever to lighting as a causal factor. In the event neither of the two studies enables us to make an economic appreciation of the situation, and this seems to be a classic example of a situation where some dovetailing of research effort would have greatly increased the useful return. On the effect of lighting on accidents, it may be noted that in 1939 Mickel presented some very interesting statistics to the Mine Managers Association of the Transvaal2, on the improvement in accident rates which followed the random issue of electric cap lamps to native mineworkers in the Hercules Section of E.R.P.M. the previous year. Based on a 12 month trial period in which 250 000 shifts were worked with carbide lamps and (contemporaneously) 307 000 shifts with cap lamps, the incidence of major accidents (at least one day in hospital among men using carbide lamps was 1,15 accidents per 1000 shifts, while the incidence of minor accidents (requiring dressing only) was 11,52 per 1 000 shifts. The corresponding figures for men using cap lamps were 0,79 and 7,31 accidents per 1 000 shifts respectively, representing a reduction of over 30 per cent in both major and minor accidents. While these figures are obviously dated - only men using cap lamps were issued with hard hats, for instance - they do indicate a need for similar research today.

Jan 1, 1971