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By Simon Mundike, Muwindwa Lipalile

A scraper based block cave method has been successfully applied to extract the Lower Ore Body at Nchanga since the 1950?s. Since inception, scraper drifts and service ways have been supported using steel arch sets fabricated to a specific design from high strength manganese steel To reduce costs and to improve productivity, trials commenced in 2002 using fibre reinforced shotcrete as an alternative support method. One of the areas; the 2420 8E 1C trial drift was subjected to abutment loading for several months prior to undercutting and cave mining. Shotcrete installed exhibited minor cracking shortly after application but very little deterioration thereafter. Following the success of the trial, the application of fibre reinforced shotcrete was extended to other drifts. This paper describes the application of fibre reinforced shotcrete at Nchanga and outlines design and quality assurance methods employed.

Jan 1, 2005

By Swapan Ghosh, Amitava Sengupta, Proloy Das

Ferro-alloys are very important ingredients used for making of quality steel with desired composition. In view of high demand in various types of ferro-alloys, it has become necessary to produce the same efficiently, safely and cost-effectively with consistent quality maintaining the anti-pollution norms. To achieve this goal, it is necessary to adopt latest process/equipment with the state-of-the-art instrumentation and automation system. A Programmable Logic Controller (PLC) based automation system with suitable Human Machine Interface(HMI) terminals along with intelligent field mounted sensing/control devices allows to monitor and control the complete plant effectively with optimum deployment of man-power. In association with this, use of process optimization controllers enables to achieve specialised functionalities of the submerged arc furnaces like material management, lining management, electrode management, power management, overall production management etc.

Jan 1, 2007

By A. Andrews

Paper written on project work carried out in partial fulfilment of MSc (Eng) degree Solid state sintered silicon carbide ceramics are used in aggressive environments as sealings. There exist data concerning corrosion, but there are only few data concerning their electrocorrosion behaviour. Therefore the electrochemical corrosion of solid state sintered silicon carbide (SSiC) ceramics has been studied at room temperature in acidic and alkaline environments by using potentiodynamic polarization measurements. The investigation showed a pronounced electrochemical corrosion in bases and acids. In HCl andHNO3pseudo-passivity features due to the formation of a thin layer of SiO2on the surface were observed, whereas in NaOH soluble silicate ions were observed, resulting in more pronounced corrosion. The microstructural observations of initial and corroded samples reveal that the residual carbon found in the microstructure do not dissolve preferentially. Keywords: Corrosion; SEM; SSiC; polarization test.

Jan 1, 2006

Leinster Nickel Operations, located in Western Australia, consists of an underground and three open pit mines in relatively adverse ground conditions. This paper reviews our ground control practices in the open pits, covering aspects of ground support, wall control and monitoring. These methods have been effective in allowing mining operations to continue beneath unstable slopes. In particular, the use of Ground probe?s slope stability radar has enabled the Harmony open pit to safely operate for months following indication of failure from traditional methods. This case study highlights the benefits of investing in appropriate slope stability monitoring systems.

Jan 1, 2006

By P. R. Labrum, H. A. D. Kirsten

The literature on shotcrete is reviewed with the object of identifying aspects that have not been addressed specifically in terms of its structural performance and manufacture as applied to underground mines. The programme and results of a series of full-scale tests on mesh- and fibre-reinforced shotcrete panels are presented, from which it is concluded that fibre-reinforced shotcrete is competent, especialy at large deformations, and is equivalent in structural performance to mesh-reinforced shotcrete for a fibre content of 3 per cent by mass: furthermore, that the support design systems developed for mesh-reinforced shotcrete are directly applicable to fibre-reinforced shotcrete. The Q-NATM system for the design of temporary tunnel support is presented briefly as one such system. It provides for the integrity of the excavation to be considered in terms of its competence and displacement determinateness, and represents the first systematic procedure for the design of temporary tunnel support. Finally, the support designed on the basis of the Q-NATM system for the main and cross-cut tunnels on the production level in the proposed BA5 block cave at Premier Mine is presented as a practical example of the design of fibre-reinforced shotcrete as part of an overall support system.

Jan 1, 1990

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. Bessinger

The present paper provides a brief overview of the thermodynamics of titania rich slags, an outline of the Multi-Phase Equilibrium (MPE) package and its application to ilmenite smelting. Through assessment of published experimental data on various systems containing TiOx, it was found that despite considerable scatter in measured phase equilibria data for the binary Ti2O3-TiO2system,the behaviour of binary and higher order titania rich slags and oxide solid solutions phases could be represented by solution models in the MPE package. Results from the applications of the MPE model on the stability of solid phases and slag-refractory interactions will be presented and discussed. Parallels will be drawn between the predictions by the model and observations made during pilot plant tests. Key words: Thermodynamics, titania slags, ilmenite smelting, phase equilibria, refractory.

Jan 1, 2003

Mr Colin M. Spence took office as President of The Federation of Societies of Professional Engineers on 1st July, 1984. Colin Maynard Spence was born in November 1921, and was educated at the Durban Preparatory and High Schools, in both of which he was a Dux Scholar. He graduated from the University of Natal in 1942 with a B.Sc. degree in civil engineering. In 1958 he received a Diploma in Town Planning from the same university. Cessation of Membership In accordance with Clauses 7.6.1 and 12.1 of the Institute's Constitution, Rules and Policy, the following members have been struck off the Membership list.

Jan 1, 1984

By A. P. I. Popoola

Laser coatings are used for a wide variety of applications. TiB2/Ni intermetallic matrix composite coatings were fabricated on Al-substrate by a high power Rofin Sinar Nd: YAG solid-state laser. The characterization of the coatings was carried out by optical microscopy (OM), scanning electron microscopy (SEM/EDS) and X-ray Diffraction (XRD). Electrochemical study of the laser coatings in 3.65 per cent NaCl at room temperature revealed that with very high weight proportion of nickel the corrosion resistance of the coatings deteriorated due the presence of AlB10 phase. 50 wt per cent TiB2+50 wt per cent Ni laser coatings exhibited the highest corrosion resistance in test solution. Keywords Corrosion, protective film, laser surface alloying, reinforcement.

Jan 1, 2011

By S. Ling, T. Liu, Y. Shang

A new copper-molybdenum flotation technology developed for a certain coppermolybdenum ore is introduced. We achieved copper-molybdenum bulk flotation in lowalkali conditions. Locked-circuit test results showed that the bulk concentrate contained 21.05% Cu and 1.10% Mo, with copper recovery of 87.37% and molybdenum recovery of 77.07%. For the copper–molybdenum separation process of the bulk concentrate, we use a new depressant, BK511, to replace the traditional sodium hydrosulfide. We achieved copper–molybdenum separation through one rougher, nine cleaner, and two scavenger processes. The results of locked-circuit tests showed that the molybdenum concentrate contained 46.19% Mo and 0.75% Cu, with molybdenum recovery of 93.80%; the copper concentrate contained 21.50% Cu and 0.069% Mo, with copper recovery of 99.92%. This new technology overcomes disadvantages of using large amounts of lime, sodium hydrosulfide, and other reagents in traditional copper–molybdenum flotation.

Jan 1, 2023

By W. Banda

Paper written on project work carried out in partial fulfilment of Phd. (Process Engineering) degree* The recovery of cobalt and copper from waste slag was studied in a plasma DC-arc furnace in reducing conditions. Three fluxes, CaO,CaF2, and TiO2, were investigated for their influence on selective recovery of cobalt into an iron-rich alloy. A further investigation on the influence of furnace power on the reduction of slag to recover cobalt to the alloy showed that a change in power setting had an unexpected effect on the recovery of metals to the alloy, in that selectivity of base metal recovery over iron recovery decreased at an increased power level. Keywords: DC-furnace, reduction, nonferrous, slags

Jan 1, 2004

By A. L. Edwards

A two-year study focused on current noise exposure levels in the South African mining industry, aimed at helping the Mine Health and Safety Council of South Africa meet its milestones for eliminating noise-induced hearing loss (NIHL). Methods A multi-task methodology was adapted from international baseline studies to determine the exposure to noise in both large-scale and small- to medium-scale mines. Results On average, 66.7 per cent of the employees sampled in year 1 and 78.4 per cent in year 2 were exposed to noise levels of above the 85 dB A legislated occupational exposure level. Conclusions Information obtained through the study could be developed into a national personal noise exposure database, including audiometric results, equipment noise emission levels and initiatives for noise engineering control by mines and equipment manufacturers to facilitate targets of eliminating NIHL. Keywords Noise exposure levels, mining industry, noise-induced hearing loss

Jan 1, 2011

By R. J. Dippenaar

In his inaugural lecture (delivered in Afrikaans at the University of Pretoria on 16th February, 1995), Professor Dippenaar defends his doctrine, philosophy, objectives, and methodology, as was required of a newly appointed professor in the days of old. Briefly, he recounts the growth and achievements of the Department of Material Science and Metallurgical Engineering at the University of Pretoria; he sketches its strategic guidelines and the obstacles encountered; he outlines the opportunities for the metallurgical industry in South Africa and the need for environmental control; and he describes how modeling techniques, together with expert systems, can aid both the industry and the community. He ends on an optimistic note, saying that his Department will continue to strive to transform adversities into opportunities, and to give its students a view of new horizons beyond the foundations laid by their teachers.

Jan 1, 1996

By B. Genc

Improving student success rates without compromising the quality of graduates is one of the biggest challenges expanding university programmes are facing in South Africa. By establishing a new Mine Design Laboratory (MDL) for higher learning in Mining Engineering, the School of Mining Engineering at the University of the Witwatersrand (Wits Mining) has achieved one of the important goals in its five-year strategic plan, i.e. to improve throughput in all years of study. Although the establishment of the laboratory has been a costly exercise, results so far have shown an improved success rate in most subjects taught in the facility. This paper outlines the design and equipment of the laboratory, the facilities incorporated, a comparison with the old laboratory, and the performance of students?all of which indicate how important it is to have proper facilities to improve the teaching of, and learning by, large classes. Through this initiative, Wits Mining has taken an important step that will contribute to addressing the skills shortages in the mining industry.

Jan 1, 2012

By G. A. Kordosky

The concept of selectively extracting copper from a low-grade dump leach solution followed by stripping the copper into an acid solution from which electrowon copper cathodes could be produced occurred to the Minerals Group of General Mills in the early 1960s.This simple, elegant idea has resulted in a technology by which about 2.2 million tonnes of high quality copper cathode was produced in year 2000. The growth of this technology is traced overtime with a discussion of the key plants, the key people and the important advances in leaching, plant design, reagents and electrowinning that have contributed to the growth of this technology. Some thoughts on potential further advances in the technology are also given.

Jan 1, 2002

By C. A. Garzonio, A. M. G. Affuso

The paper describes the analyses and the tests carried out on representative slabs of white Carrara marble which have highlighted the correlation between the micro fabrics and physical and mechanical parameters. The aim is to determine the conditions which indicate the triggering and evolution of the deformation phenomena. La note écrit l’analyse et les epreuves effectuée sur un echantillon représentatif de nombreuses dalles en marbrede Carrara. Les études montrent la correlation entre la minéralogie et les paramètres physiques et mecaniques. Le but est déterminer les conditions qui indiquent l’amorçage et l’evolutions des phénomènes de déformation. Diese Arbeit gibt eine Beschreibung der experimentalen Untersuchungen und der Analysen über die Marmorplatten von Carrara. Daraus resultiert, dass die Charakterisierung der Mineralogie und die Porosität der Gesteinsmaterialien die physikalische mechanische Degradation beurteilen und die Krümmungen bestimmen.

Jan 1, 2003

By A. C. du Preez

The separation of nickel and cobalt from calcium, magnesium and manganese by solvent extraction using synergistic mixtures of carboxylic acids was studied. Addition of certain viable synergists to commercially available tertiary branched carboxylic acids, such as Versatic 10 (Shell) or Neodecanoic acid (Exxon), produced large synergistic shifts (?pH50) in the pH50values for nickel, and small antagonistic shifts (negative ?pH50values) in the extraction of calcium. Under the initial test conditions used (0.50 M each of Neodecanoic acid and the Mintek synergist, in xylene) a large separation (pH50Ca? pH50Ni= 3.09 pH units) between nickel and calcium in their extraction from 1.00 M sodium nitrate solutions was obtained, compared with only 1.11 pH units in the absence of the synergist. The selectivity series for the extraction of divalent base metals from 0.333 M sodium sulphate solutions by 0.50 M Neodecanoic acid and 0.25 M of the Mintek synergist in C12-C13aliphatic diluent was found to lie in the order (with pH50values in parentheses): Cu(3.42) > Ni (5.08) > Zn (5.58) > Co (5.73) > Mn (6.62) > Ca (7.48) >Mg (8.25). In batch counter current experiments, a simulated leach liquor containing (in gL-1): Ni 5, Mg 5, Mn 2, Co 0.5, Ca 0.5, Cu 0.1and Zn 0.1 was contacted with the mixed extractant in three stages at unit phase ratio and an equilibrium pH of 5.9. The recovery of nickel was 99.9 per cent and that of cobalt was 84.7 per cent, whilst the co-extractions of manganese, calcium and magnesium were 2.7,1.5 and 0.04 per cent, respectively. The recovery of cobalt can be enhanced by employing a slightly higher pH, although this will also increase the extraction of manganese, calcium and magnesium somewhat. Nearly quantitative stripping (99 per cent) of nickel from the loaded organic phase was achieved in a single contact at an organic-to-aqueous phase ratio of 4 using a simulated spent electrolyte containing 39 gL-1sulphuric acid and 33 gL-1nickel,thereby producing an ?advance electrolyte? containing 57 gL-1nickelat pH 3.5. Loading of acid into the organic phase was very slight, amounting to only 0.002 M H+in contact with the above-mentioned spent electrolyte. Keywords: solvent extraction; synergism; nickel; calcium; carboxylic acids.

Jan 1, 2004

By L. Gunnewiek

An advanced real-time monitoring system called the tapblock diagnostic system (TDS) has been developed. The purpose of the TDS is to help furnace operators manage the safe operation and economical maintenance of furnace tapblocks. This system is an evolution of the current practice of using historical records and operator interpretation to assess the ?health? of a tapblock. The main parameters affecting tapblock health are heat removal capacity and refractory wear, and these are currently difficult to assess in situ except in a global way. By using monitored and operating data together with predictive numerical modelling and multivariate statistical methods, real-time tapblock performance is assessed relative to expected performance. A state indicator in the form of a green, yellow, and red light is used by furnace operators to monitor the tapblock performance and health status during operation. Access to historical operating data and the provision of diagnostic functions allow for probable health degradation events to be deeply investigated. A recent opportunity to evaluate the actual performance of a first generation TDS installed in the KIVCET furnace at Teck Cominco?s Trail Operations showed that a reasonable estimate of tapblock health was made. However, the evaluation also found that some areas of refractory wear were missed, and a new mechanism affecting refractory wear was discovered that was not previously known. This has reinforced the belief that there is a need to develop improved methods of monitoring so that data used to define the health of the tapblock is more comprehensive and accurate.

Jan 1, 2008

This paper reviews ore pass practice in some Canadian mines in Quebec and Ontario. In particular it reviews ore pass configuration, flow control mechanisms and monitoring practice. A review of the type of problems encountered and the tools to restore flow is also presented.

Jan 1, 2005

By B. P. Gilbertson

In her wonderful book, 'The Guns of August', historian Barbara Tuchman tells us that the French war plan for 1914 was dedicated entirely to an offensive strategy, not a defensive one. Plan 17, as it was called, concentrated everything on a French advance to the Rhine, leaving the French left virtually unguarded. This strategy could only be justified by the fixed belief that the Germans could not deploy sufficient manpower to extend their invasion around through western Belgium and the low provinces; and this in turn was based on the belief that the Germans would never use reserve troops in the front line. Al evidence to the contrary was ignored. But when the war came, the Germans followed Count Von Schlieffen's plan; they did use reserves in the front line and they did come the long way around on the west. The result- as you know-was a protracted war, with fearful consequences for the rest of our century.

Jan 1, 1994