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By G. J. G. Juby

The Chamber of Mines Research Organization has been evaluating three membrane-desalination processes for use within the South African mining industry. These processes are electrodialysis reversal (EDR), tubular reverse osmosis (IRO), and slurry precipitation and recycle reverse osmosis (SPARRO). The evaluation of EDR and TRO is complete, and the operating costs (1988) associated with each process are expected to be about 50 cents per kilolitre for a plant of 50 l/s (4 Ml/d) installed capacity. The SPARRO process is still being evaluated. Pilot plant results, water Qualities, and expected capital costs are presented where appropriate.

Jan 1, 1992

By S. Krishnannair

Singular Spectrum Analysis (SSA) is an effective data-adaptive multimodal tool for monitoring chemical processes. However, monitoring multiscale signals using principal component analysis obtained from the multilevel decomposition of process signals using basic SSA assume the upper control limits of monitoring charts (" ) to have a Gaussian distribution. This assumption deteriorates the performance of basic SSA when applied to the monitoring of nonlinear processes. To address the issue in this paper, the kernel density estimation (KDE) was used to estimate upper control limits of monitoring charts for basic SSA based nonlinear process monitoring techniques. The monitoring performance of the resulting basic SSA-KDE approach was then compared with a basic SSA approach of which upper control limits of the monitoring charts were determined based on a Gaussian distribution. Application on nonlinear dynamic simulated process and base metal flotation plant chemical processes showed that the SSA-KDE approach provided better overall performance than the SSA approach with Gaussian assumption-based upper control limits for its monitoring charts. Keywords: Fault detection, singular value decomposition, singular spectrum analysis, kernel density estimation

Jan 1, 2020

By M. L. Mahlatji

Mechanical alloying of an equiatomic mixture of crystalline Ti and Pt elemental powders in a high-energy ball mill formed an amorphous alloy by solid-state reactions. Mechanical alloying was carried out in an argon atmosphere at a rotation speed of 1200 r/min and a 20:1 ball-to-powder weight ratio, for time intervals of 4 to 40 hours. At an intermediate stage of mechanical alloying, scanning electron microscopy showed the formation of characteristic layered structures of inhomogeneous composition within the powder particles. X-ray diffraction analysis showed the gradual disappearance of crystalline Bragg peaks and the emergence of broad amorphous maxima as milling progressed. The amorphization process was completed after 8?12 hours. The amorphous state of the product indicated that temperatures during processing did not exceed the crystallization temperature of the alloy.

Jan 1, 2014

The Federation of Societies of Professional Engineers Our Institute is a member of the Federation and, to give members some idea of the work of the latter body, a few notes are submitted from the Federation's annual report for the year ended June 1973.

Jan 2, 1974

By W. Spencer

An examination is made of quality standards in castings produced by the South African foundry industry, and some examples are given of the consequences of poor quality to the user. Corrective measures are suggested.

Jan 1, 1981

By Wei Sun, Ruolin Wang, Wenjuan Sun, Junhao Fu, Haisheng Han, Zhao Wei

Pb–benzohydroxamic acid (BHA) (lead complexes of benzohydroxamic acid) exhibits high selectivity but low collecting efficiency in scheelite flotation. This paper reports the manner in which BHA and sodium dodecyl sulfate (SDS) were employed as ligands to coordinate with the lead ions to obtain a colloidal lead-group multiple ligand complex, i.e., the Pb–BHA–SDS, for improving the collecting efficiency of Pb–BHA. The flotation mechanism of Pb–BHA–SDS with respect to scheelite was investigated from the viewpoint of interface science based on the pure mineral flotation, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and contact angle measurements. The results showed that the BHA and SDS coordinated with Pb2+ to form novel leadgroup multiple ligand complexes, which are different from the traditional understanding associated with the mixed collectors. Pb–BHA–SDS was a better collector with stronger collecting ability and excellent selectivity in regard to a scheelite flotation than Pb–BHA. The addition of SDS to Pb–BHA enhanced the latter’s adsorption ability on the scheelite surface and improved the hydrophobicity of the collector’s nonpolar groups, rendering Pb–BHA–SDS as a more efficient collector at a low dosage. Keywords: Scheelite; Pb-BHA complexes; sodium dodecyl sulfate; multiple ligands; Pb–BHA–SDS

Jan 1, 2020

By C. van Buuren, R. F. Sandenbergh, P. J. Pieterse

Gold extraction from double refractory ores using conventional cyanidation has proved challenging due to the presence of carbon within the ore. Carbon particles may adsorb leached gold resulting in gold losses to tailings, i.e. preg-robbing the gold. Some of the preg-robbed gold may be recovered by the application of the HiTeCC process on CIL tailings. The process developed by Metso Outotec involves caustic conditioning of the tailings followed by high temperature desorption and simultaneous adsorption onto virgin activated carbon of the aurodicyanide. The aim of this paper was to develop a model for the HiTeCC process which could be used to support design and optimisation of the process, based on the adsorption characteristics of the preg-robbing and activated carbons. It was found that accurate experimental isotherms can be used to predict the behaviour of preg-robbing adsorbents. Comparing the sorption isotherms for preg-robbing ores and activated carbon indicated similar dependencies on temperature and ionic composition. Applying boundary layer diffusion models coupled with experimentally determined isotherms for preg-robbing ore and activated carbon, the HiTeCC process was successfully simulated at experimental and plant scale. Gold recovery of the HiTeCC process is most sensitive to the temperature of desorption and gold loading of the activated carbon, with increased temperature improving recovery. The gold loading of the activated carbon in the process should always be maintained lower than that of the normalised pregrobbing carbon gold loading to ensure favourable conditions for adsorption onto the activated carbon. Caustic conditioning stabilises adsorption and is therefore not necessary during the desorption stages of the process, but potentially improves recovery during adsorption. Keywords: Preg-robbing, refractory gold ores, HiTeCC, aurodicyanide

Jan 1, 2020

By R. P. Plewman

The Chemical, Metallurgical and Mining Society, from which The South African Institute of Mining and Metallurgy is descended, had as its coat-of-arms a green shield with a very flat gold chevron dividing the field into two. A crossed pick and shovel occupied the lower half, and an alembic (distilling vessel) and a flaming crucible occupied the top half.

Jan 1, 1982

Specifile compendium' 80. Mining and engineering. (Obtainable from Specifile, P.O. Box 7870, Johannesburg 2000.) Reviewer: J. D. Austin SKF Steel. Plasmasrnelt information brochure. Hofors (Sweden), SKF Steel, 1980. Reviewer: N. A. Barcza POTENTIAL VALUE OF COLLIERY DISCARD MATERIAL By R B MacGillivray, Pr Eng, BSc(Eng) Rand, C Eng (Fellow) Preprints of perhaps the most thought-provoking of the papers delivered at the Witbank Coal Colloquium - 'Potential value of colliery discard material' by Roy MacGillivray of Rand Mines - are available on request from the South African Institute of Mining and Metallurgy. Mr MacGillivray outlines an imaginative plan to utilize the annual nine million tons of colliery discard in the WitbankBethal areas. Two SAIMM colloquia The South African Institute of Mining and Metallurgy (SAIMM) is organizing two one-day colloquia in the State Pavilion, Milner Park showgrounds, Johannesburg, to coincide with the Electra Mining Exhibition on 16th and 17th September. Over a million rands worth of equipment will be on display, the Electra Mining Exhibition being rated among the four or five largest in the world. The 1978 Electra Mining Exhibition was attended by 24 000 visitors. "Project Management in the Metallurgical Industry", "Mine Fires" APCOM International Conference by H. W. GLEN The 17th APCOM Conference (under the auspices of the Council for the Application of Computers and Mathematics in the Mineral Industries) was to have been held in Moscow during the last week in October. South Africans have always given enthusiastic support to the APCOM series of meetings, since their inception in 1961. The conference was held in the Republic in 1972.

Jan 1, 1980

By S. R. Stadler

Koffiefontein Mine commissioned a distributed antenna system as an underground communication backbone for the DISPATCH® production management system during September1999. STAS Ltd, the supplier of the Distributed Antenna System developed the System for an Integrated and Automated Mine (SIAM). This communication system, in conjunction with DISPATCH®, fulfils Koffiefontein Mine’s present and future requirements for accurate draw control, increasing productivity and improving working conditions. The DAS as SIAMnet communication network was selected by the mine, because of its superior data transmission rate of up to 1.5Mbps at 860MHz, video and Ethernet transmission facilities, and future enhancement abilities. The results of the commissioning tests confirmed the quality and integrity of the data and voice communication. The initial installation enabled 9000 metres of underground production tunnels with voice communication inclusive of 3700 metres having data communication. This article discusses the requirements and selection of the telecommunication system for an underground mine. A description of the installed distributed antenna system follows with a summary of the commissioning tests. A discussion of the reliability of the components is followed by conclusions with suitable recommendations. Keywords: distributed antenna system, underground mining, telecommunication system.

Sep 1, 2001

By F. Nakhaei, Z. Pourkarimi

Tailings produced from the iron ore industry present many challenges due to the high economic and environmental impacts involved with their disposal. However, the relative scarcity of high-grade iron ores has driven manufacturers to recover and recycle these valuable tailings (secondary sources). This study aimed at the purification of ultrafine tailings with high sulphur content from an iron ore concentrator via reverse flotation to produce pellet feed fines. A specially designed flotation column featured with a nano bubble generator and a conventional bubble generator were employed to assess the effects of nano bubbles on the desulfurisation performance of iron ore concentrate under different operating conditions. Results obtained from this study indicated that the sulphur content of iron concentrate could be reduced from 1.2% to 0.22% in the presence of nano bubbles. Also, the results showed that use of nano-micro bubbles increased sulphur recovery 20% more, in comparison to micro bubbles. Keywords: Column flotation, iron ore, tailings, slime, nano bubbles, desulphurisation

Jan 1, 2020

By Z. Zitron, G. J. de Korte, D. W. Horsfall

This paper summarizes work carried out on the treatment of fine coal, nominally classified as minus 0,5 mm (wedge-wire screen), which is removed from the raw coal prior to the treatment of the plus 0,5 mm sizes. The minus 0,5 mm coal divides, for treatment purposes, into fines, nominally between 500 and 150 !tm, and ultrafines, nominally minus 150 !tm. Studies on processes for the treatment of minus 0,5 mm coal are discussed, and the lower size limit beneficiated is indicated for each process. The installation and operational results from a pilot froth-flotation plant treating minus 150!tm coal are described.

Jan 1, 1986

By R. J. Davidson, V. Veronsee

Some of the parameters affecting the elution of gold from freshly loaded activated carbon using pure water as an eluant were studied. The procedure involved pretreatment of the gold-loaded activated carbon with a strong reagent of sodium cyanide and sodium hydroxide, followed by elution of the gold with water. Gold-loaded carbon obtained from three different sources was studied. It was shown that the elution temperature was the most critical parameter, and column operation at I !OCC (gauge pressure of 50 to 100 kPa) is suggested. The effects of variations in the concentration of sodium cyanide required for the pretreatment of loaded carbon and of variations in elution flowrate were also investigated. Both these parameters were found to have only a marginal effect on the efficiency of gold elution. The investigation also indicated that gold-elution rates were affected to a considerable degree by the particle size of the carbon concerned. Higher elution flowrates could be used when carbons of finer particle size were eluted. A modified eluate-collection procedure was also developed during the course of the investigation. Oven-drying of the loaded carbon was shown to have little or no effect on the efficiency of the subsequent gold elution. The calcium and silica contents of the various carbon samples were also determined. It was immediately evident that the calcium content was very considerable in the case of loaded carbons originating from carbon-in-pulp operations. Calcium concentration was particularly high where air agitation had been employed in the carbon-contacting circuit. To some degree, the calcium build-up explains the serious carbon fouling taking place, resulting in a decreased efficiency of gold adsorption. The fouling problem was found to be less severe when mechanical agitation was used. No poisoning by calcium carbonate was observed where the pregnant solution had been acidified before it was contacted with the carbon.

Jan 1, 1979

"Chairman: Mr. K. F. LaneRapporteur: Mr C. T. ShawPapers:Design of crushing plant flow sheets by simulation by T. GurunThe impact of transportation networks upon the potential supply of base and precious metals from Sonora, Mexico by P. de V. Harris and D. E. EurestyProfitability sensitivity analysis of a mining venture by C. A. Beasley and E. P. PfleiderTechnological innovation and its potential effect on the opening of new gold mines in South Africa by N. C. JoughinMr Turgay Gurun, in presenting his paper, indicated that this simulator was no purely theoretical exercise, but that the model had been used in the design of crushing plants of capacities ranging from 3 000 tons per day to 66 000 tons per day, and that recently the design of a plant of capacity of 99 000 tons per day had been studied.The crushing plant simulator was an independent portion of a much more comprehensive simulator for the design of a. complete recovery plant. It would be possible to use each section of this simulator on its own, and simulators would be designed to cover flotation concentrates, cash flow analyses of the entire project, and so on.Each simulator would be backed by a comprehensive data bank. For example, the crushing plant simulator was backed by such a data bank which included the performance and cost data from five manufacturers for an average of 30 items of process and materials handling equipment each. This meant that data preparation involved generally less work than would be required for a manual calculation. On average, data preparation for one run took 30 minutes and three minutes of computer time on an IBM 360/40 completed the run. The model could be valuable as a design tool in that it allowed the designers an opportunity to make a thorough examination of many alternative designs. It was also of value to plant operators as it could be used to predict the consequences of operating decisions.This paper generated much interest and there were numerous questions and contributions, so many, in fact, that the discussion had to be cut short.It was pointed out by Mr K. F. Lane that crushing plants represented a very large capital investment. A plant designed for 40 000 tons per day at 98 per cent efficiency might well in practice be run at 50 000 tons per day at, say, 83 per cent efficiency. He asked how, therefore, their design could be investigated without building economic criteria into the model? The author conceded that this was a tender point. He would have liked to have given facilities for more variability of the metallurgical information. He pointed out, however, that while there was no overdesign for conservatism built into his system, some overdesign was inevitable as the performance characteristics given by the manufacturers were generally conservative. Also, in his system, if lower recovery was allowed for, the system would nut through more tonnage."

Jan 1, 2014

By J Taguta, B. McFadzean, P. E. Ngoepe, M. G. Mulaudzi

Computational modelling methods and isothermal titration calorimetry (ITC) were employed to investigate the interaction of a pyrite surface with thiol collectors. Modelling work was conducted in the presence and absence of water. Microcalorimetry was employed to investigate the resultant energy of interaction pyrite as a result of mineral-collector interactions. Sodium ethyl xanthate (SEX), diethyldithiocarbamate (DTC) and diethyl dithiophosphate (DTP) were investigated in this study. The results showed that the calculated surface energies and morphologies for FeS2 showed that (100) and (111) are the most stable surfaces. The morphology also indicated the appearance of the (100) and (111) surface facets and no presence of others. The calculated adsorption energies between thiol collectors and the pyrite surface were always more exothermic than the experimentally determined ones. When comparing different ligand types with the same alkyl chain length, the heat of adsorption of diethyl-DTC was greater than that of ethyl xanthate and diethyl-DTP for pyrite. Experimentally, the diethyl DTP barely adsorbed onto the pyrite surface and this may be due to a different mechanism of action. In computational calculations, water adsorption was found to reduce the reactivity of the Fe atom for the interaction with thiol collectors, and bring the adsorption energies closer to the magnitude of the experimental values. Keywords: Computational modelling, microcalorimetry, experimental and thiol collectors, adsorption energies

Jan 1, 2020

By K. B. Le Bron, T. van Aard

The empirical pillar strength formulae have been widely, and in most cases successfully, applied to design underground pillars for mines in the Bushveld Igneous Complex (BIC). This paper presents the case for combining the empirical method with numerical modelling when it comes to crush pillar stability analyses. The benefits include an understanding of potential failure mechanisms, which may then be accounted for in the designs. In addition, the impact of weak layers, such as shear zones, the impact of the dip of the orebody, differences in layouts, such as holing widths and the presence of advanced strike gulleys (ASGs) immediately adjacent to the crush pillars, and stress regime (k-ratio) may be studied using numerical modelling, as it is not accounted for in the empirical method.

Mar 5, 2025

NOTICE The Institute has received requests for copies of Uranium in South Africa', Vols. 1 and 2, but is unable to supply, as all copies have been sold out. If any members have copies they wish to dispose of it would be appreciated if they would contact the Secretary, P.O. Box 1183, Johannesburg. Telephone 834-1271.

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).

Book review Doyle, William S. Strip Mining of Coal; Environmental solutions. Park Ridge (New Jersey), 1976. 352 pp. $32. Surface mining of coal is still in its infancy in South Africa. The environmental repercussions following large-scale disturbance of the land surface, and the secondary effects of the disposal of waste products and effluents from mining, have not yet become apparent.

Jan 1, 1977