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By T. S. Kagogo

The factors affecting haul truck tyre performance and the effectiveness of the management system at Rossing Uranium Mine were investigated with the aim of increasing tyre performance in terms of running hours until failure. The main objectives were to identify the types of tyre failure, their causes and cost implications, and evaluate the effectiveness of the management system. A site severity survey, weight study, and TKPH studies were conducted to determine the pit conditions, and an analysis of failed tyres carried out. The results showed that tyre performance at the mine has declined from 2009 to date, and the increase in lost value amounted to R5.7 million in 2012 alone. The main cause of tyre failure is loose rocks in the pit. The present management system in the load and haul department is not effective enough due to operational constraints it is facing.

Jan 1, 2014

By T D. Sullivan

Risk lies at the heart of all mining and nowhere more so than in pit slope design. Mining is principally about two areas of risk; safety and economics. This paper addresses the main elements of pit slope design and presents a view of the state of the art in terms of safety, design, prediction of performance, success and pit slope management. There has been a recent trend for serious injury and fatalities due to stability in open pit mines. The causes and contributing factors are analysed in relation to geotechnical knowledge, pit slope design and management. Currently there is no standard classification system for mine slope designs and it is considered doubtful if a universal system is possible. Designs are usually formulated in accordance with many different methodologies, various engineering principals and a number of different philosophical approaches, with results often presented in terms of Factors of Safety or Probabilities of Failure. However wide experience has demonstrated that even with apparently detailed engineering investigation and analysis at Feasibility Level, at the Operating Stage mine slope angles are regularly subject to large changes. The general experience is that these changes are ± 5° and 16° overall, which is considerably outside the accepted order of accuracy. For large deep mines these are huge changes and represent significant risks to the operations. The current state of practice in pit slope design is examined for two stages, feasibility and operating.

Jan 1, 2006

By J. Y. Foley, K. Eden, A. E. Grosz, C. J. Giles, J. E. Grosz

"Portions of the Icy Cape placer Au district have been described and exploited since the early 1900s. Industrial studies of Au-bearing garnetrich intervals established a 3.5 million troy ounce resource in the western half of the district. This estimate is not compliant with CIM and SME definition standards for Mineral Resources and Mineral Reserves. We note high variability in the textures of sediments and their heavy mineral (HM) content and composition in the district, probably as a function of the depositional environment. Sediments are medium- to fine-grained sands with a valuable HM assemblage that averages 26.0% in a range of 1.1– 72.6%. Valuable heavy minerals (VHMs) garnet, magnetite, ilmenite, rutile, and zircon, but excluding Au, average 7.9% in a range of 1.0–37.6% of the HM assemblage. Trace quantities of uraninite, thorite, monazite, xenotime, and others are noted. Garnets have an average Y content of 726 ppm with a range of 0–2150 ppm. Energy-dispersive X-ray fluorescence confirms compositions commensurate with Ca, Al, and Mg silicates. We provide empirical analytical data and note high variability in the textures, HM content, and compositions as a probable function of depositional environment. Icy Cape District land and resources are owned by the Alaska Mental Health Trust Authority and managed by the Trust Land Office (TLO). IntroductionThe Icy Cape Heavy Minerals (HM) District in Alaska subtends more than 200 km2 fronting the Pacific Ocean and backing to the foot of the Robinson Mountains at about 1700 m above sea level. We classify the district into geomorphic provinces; the eastern region as deltaic (Figure 1) and the western region as coastal plain (Figure 2), based on geomorphologic expressions. The coastal plain is entirely built up of unconsolidated outwash sediments and ancient beach sand deposits."

Jan 1, 2017

By T. M. Evers, R. P. Van Den Berg

Ancient mining in Southern Africa, with reference to a copper mine in the Harmony Block, north-eastern Transvaal T. M. EVERS. B.A. (Birm.) (Visitor) and R. P. VAN DEN BERG. B.Sc. (Wits.) (Visitor) A recently discovered mine on the farms Harmony 24 and 25 in the Letaba district has been investigated archaeologically by T. M. Evers and geologically by R. P. van den Berg. The archaeological investigations shed light on the mining techniques and accompanying metallurgical techniques, while the geological investigations give information on the structure and mineralization of the mine. Comparisons with other investigated ancient workings show that mining was well understood in Iron Age times, before the African peoples had any contact with Europeans.

Jan 1, 1974

By J. Y. Foley, K. Eden, A. E. Grosz, C. J. Giles, J. E. Grosz

"Portions of the Icy Cape placer Au district have been described and exploited since the early 1900s. Industrial studies of Au-bearing garnetrich intervals established a 3.5 million troy ounce resource in the western half of the district. This estimate is not compliant with CIM and SME definition standards for Mineral Resources and Mineral Reserves. We note high variability in the textures of sediments and their heavy mineral (HM) content and composition in the district, probably as a function of the depositional environment. Sediments are medium- to fine-grained sands with a valuable HM assemblage that averages 26.0% in a range of 1.1– 72.6%. Valuable heavy minerals (VHMs) garnet, magnetite, ilmenite, rutile, and zircon, but excluding Au, average 7.9% in a range of 1.0–37.6% of the HM assemblage. Trace quantities of uraninite, thorite, monazite, xenotime, and others are noted. Garnets have an average Y content of 726 ppm with a range of 0–2150 ppm. Energy-dispersive X-ray fluorescence confirms compositions commensurate with Ca, Al, and Mg silicates. We provide empirical analytical data and note high variability in the textures, HM content, and compositions as a probable function of depositional environment. Icy Cape District land and resources are owned by the Alaska Mental Health Trust Authority and managed by the Trust Land Office (TLO). IntroductionThe Icy Cape Heavy Minerals (HM) District in Alaska subtends more than 200 km2 fronting the Pacific Ocean and backing to the foot of the Robinson Mountains at about 1700 m above sea level. We classify the district into geomorphic provinces; the eastern region as deltaic (Figure 1) and the western region as coastal plain (Figure 2), based on geomorphologic expressions. The coastal plain is entirely built up of unconsolidated outwash sediments and ancient beach sand deposits."

Jan 1, 2017

By Z. Yang, X. Bian

"The synthesis of 3-hydroxy-2-naphthyl hydroxamic acid (H2O5) as a collector for bastnaesite is described. The flotation performance of H2O5 with respect to bastnaesite was investigated by flotation tests, measurements of the surface adsorption capacity, and polarizing microscopy. The results indicated that H2O5 exhibits superior collecting performance compared with direct flotation recovery of bastnaesite, with recoveries above 90% at pH 8–9. The adsorption mechanism of H2O5 on bastnaesite was studied by solution chemistry analysis and ?-potential tests. The results showed that the adsorption of H2O5 is associated with the types and concentrations of hydrolysis products of rare earth cations on the bastnaesite surface. At pH 8–9, the hydrolysis-dominant components RE(OH)2+ and RE(OH)2 + of the rare earth cations were adsorbed onto the bastnaesite surfaces, which were considered to be the major positive active points and were beneficial to chemical adsorption of the reagents. The pH range of 7–10 was optimum for bastnaesite floatability, and the adsorption of H205 on bastnaesite was by means of chemical adsorption through formation of a five-membered ring chelate. IntroductionThe rare earth elements (REEs) have long been known as ‘industrial gold’ and are widely used in the petroleum, chemical, ceramic, metallurgical, and permanent magnet material industries because of their special physicochemical properties (Chen, 2011; Krishnamurthy and Guptac, 2002; Esquivel, Bohe, and Pasquevich, 2002; Abrahami, Xiao, and Yang, 2015). Demand for REEs is growing in response to continuous advances in science and technology. Currently, most REEs are extracted from bastnaesite ((Ce,La)CO3F) (Chelgani et al., 2015; Yosry, 1990), which is recovered from rare earth ores by flotation. Typically, hydroxamic acids are used as bastnaesite collectors (Xu, 2015; Ren, 1997; Mousumi and Venugopal, 2016). Research into the mechanism of interaction between hydroxamic acids and bastnaesite is important for improving the recoveries of bastnaesite. However, there have been few studies that examine this mechanism."

Jan 1, 2017

The following comment has been received from Mr A. D. Osche* on the above paper, which was published in the Journal in October 1977 (vol. 78, no. 3, pp. 51-62). Obituary: T. K. Prentice The Institute records with deep regret the death on 30th January of its senior surviving Past President, Mr Thomas Kennedy Prentice, at the age of 83. Book reviews R. A. Rich, H. D. Holland, and U. Petersen. Hydrothermal uranium deposits. (Developments in Economic Geology, vol. 6). Amsterdam, Elsevier Scientific Publishing Co., 264 pp. with 77 illustrations and diagrams, 30 tables. U.S. $34,75. M. David. Geostatistical ore reserve estimation. Amsterdam, Elsevier Publishing Company, 1977. 364 pp. World mineral industry The Australasian Institute of Mining and Metallurgy is celebrating its sesquicentenary in 1979. A conference will be held in Perth from 13th to 18th August, 1979, as part of the celebrations, the theme being 'Australia's Role in the World Mineral Industry'. Engineering teaching staff UNESCO has extended its technical assistance to the Venezuelan government in the training of engineers to suit the rapidly developing economy of the country. UNESCO vacancy Vacancy for a post of expert under the UNDP. (1) Title of post: Expert in metallurgical engineering. (2) Duty station: Instituto Universitario Politecnico of Ciudad Guyana (Venezuela). Shell Design Awards The annual Shell Design Awards, organized by the Design Institute and sponsored by Shell South Africa (Pty) Ltd, focus attention on achievements in South African design.

Jan 1, 1978

By N. A. Barcza

INFACON 7, the seventh International Ferro Alloys Congress, took place in Trondheim, Norway, in June 1995. The main aim of the Congress, which was held under the auspices of Euroalliages and the Norwegian Ferroalloy Research Organization, was to present the challenges facing the ferro-alloys industry on the road to the 21st century. Halyard Tveit, Chairman of the Technical Committee, summarized these as: ? the transition to a single global market economy ? new demands with regards to quality arising from customer needs, and ? increased awareness of the global environment. In the Plenary Sessions Kouichi Nakamura (Nippon Steel) outlined, from the steel industry's point of view, the relationship between technical advances in the products and more demanding ferro-alloy specifications. Advances in steel manufacturing technology and higher product quality have been supported in the past by raising the quality standards of ferro-alloys. Future requirements are bound to bring about more severe standards, and these need to be established by common agreement between both industries.

Jan 1, 1996

By J. Petersen, T. Moyo, D. Maharaj

This study investigates the effect of ammonium thiosulfate on the leaching of gold from the contacts of unpopulated cut electronic printed circuit boards (PCBs). Studies in the literature show ammonium thiosulfate to be a viable option in comparison to the commonly used but hazardous cyanide leaching route. However, the simultaneous dissolution of Cu interferes with the Au leaching reaction, often limiting the extraction to moderate levels. To optimize the system, an ammoniumthiosulfate system containing 0.5M ammonia, 0.5M ammonium thiosulfate, and Cu(II) sulfate at varying concentrations was studied as an alternative hydrometallurgical option for the recovery of gold from PCB. Tests were done with unpopulated standardized model PCBs (cut to 15 x 30mm pieces). Gold extraction of 47.3% was achieved after a 24-hour leaching experiment with a 0.02M copper background concentration. Further experiments focused using different initial background Cu concentrations (0M – 0.1M) to determine its effect on both gold and copper extractions. An initial Cu concentration of 0.045M resulted in the highest gold extraction, with 93.7% extraction after 6 hours of leaching. Further analysis of the data shows that the kinetic rate of gold leaching is correlated in a first-order dependence with the actual copper concentration in the solution, which increases with the concomitant dissolution of copper and gold from the PCBs. A lower threshold of 0.017M and an upper threshold of 0.15M copper in solution were determined, in between which gold extraction shows this first-order rate increase. The upper threshold is potentially linked to the onset of copper precipitation, which blinds the metal surfaces, slowing further leaching. The findings of this study suggest that in an industrial recovery operation of gold from waste PCB using the thiosulfate method, copper concentrations need to be carefully monitored, and the process should preferably operate with uncut or coarsely cut untreated boards to minimize exposure to copper circuits.

Dec 11, 2024

By P. S. G. Leon

One of the most difficult areas in concession contracts in resource-rich developing countries is achieving an equitable balance between the interests of investors, host states and, increasingly, mine and near mine communities. While some countries in the Andean region have resorted to outright or creeping expropriation of natural resource contracts under the guise of resource nationalism, others such as the Democratic Republic of the Congo (DRC), have claimed international best practice in the review (and setting aside) of important concession contracts.

Jan 1, 2011

This report describes the investigational work on the development of a fire-assay method capable of concentrating, in a button of nickel sulphide, all six of the platinum-group metals present in samples of ores, concentrates, and mattes. In the method adopted, the sample is fused with a mixture of sodium carbonate, sodium tetraborate, nickel carbonate, and sulphur. The nickel sulphide formed during fusion collects the noble metals and carries them to the bottom of the crucible. The nickel sulphide button is dissolved, and the noble metals are isolated and determined. The coefficients of variation range between 1,0 and 4,9 per cent for the various platinum-group metals when they are present in concentrations between 0,3 and 75 p.p.m.

Oct 15, 1971

1. Book reviews Mining and metallurgical practices in Australasia. Melbourne, Australian Institute of Mining and Metallurgy, 1981. $40 (incl. surface postage). Reviewer: M. G. Atmore Coal mine ground control, by Syd. S. Peng. 1978. Reviewer: C. F. Engelbrecht Sixth Annual International Conference on Coal Gasification, Liquefaction and Conversion to Electricity, July 31 -August 2, 1979. Pittsburgh, School of Engineering of the University of Pittsburgh, 1980. Reviewer: S. T. J. van Rensburg This book is a useful general reference volume on the topics covered provided a great deal of technical detail is not required from it. It consists of 29 papers, which are arranged under 6 headings. Flotation agents and processes. Technology and applications, edited by M. W. Ranney. Park Ridge, D.S.A., 1980. $48. Reviewer: R. P. King 2. New books Project control manual, by Sven R. Red. 250 pp. in loose-leaf binder. U.S. Al47. (Obtainable from the author at Bray Studios, Windsor Road, Windsor SL45 UG, England.) Manganese deposits, by Supriya Roy. London, Academic Press, 1981. 400 pp. Joint preparation for welding (set of overhead-projector transparencies). Abington (England), The Welding Institute, 1980. £34 per set. Electron micrographs of clay minerals, by T. Sudo,S. Shimoda, R. Yotsumoto, and S. Aita. Amsterdam, Elsevier, 1980. 228 pp. Dfl.150. Weld pool chemistry and metallurgy. Abington (England), The Welding Institute, 1980. 357 pp. $27. 3. New journal ...being known as Gliickauf + Translation, at an annual subscription of 396 DM for 24 issues per year. It is available from Verlag Gliickauf GmbR, D-4300 Essen I, P.O. Box 103945, Federal Republic of Germany. 4. Canadian MRI publications During 1980 the Mineral Policy Sector introduced a new series of reports identified by the prefix MRI. These cover internal studies and analytical works on a wide variety of subjects, that for one reason or another, do not reach the publication stream of the regular series yet may be of interest to readers in this 'unpublished form'. Twenty-four such titles are listed below. Exploration planning A series of professional advancement seminars for the mineral industry is to be held at Rhodes University from 12th to 20th August, 1981. The series, entitled 'Economic Guidelines for Exploration Planning', will be conducted by Professor B. W. Mackenzie, and the attendance will be limited to 30 participants. The seminars are intended Seminar on Geostatistics A seminar for mining executives on Geostatistics and Decision Making in the Mining Industry is to be held in Toronto from 23rd to 25th September, 1981. v

Jan 1, 1981

By R. T. Rudd

DISCUSSION R. T. RUDD I have the following comments on Mr Bosman's paper. Before giving the company permission to discharge neutralized mine drainage containing 1800 mg/l of dissolved solids into a public stream, my Department had to consider the matter from both the legal and the practical viewpoint.

Jan 4, 1974

By P. C. Schutte

There have been several high-profile accidents in the South African mining industry where fatigue was identified as either causal or contributory. The risk of fatigue is inherent in any work-time arrangement involving shift work and work that is physically or mentally demanding, repetitive, or requires high vigilance. The management of fatigue is not simply a matter of correct shift scheduling. Amore comprehensive approach is needed. In order to be successful, a fatigue management programme should address the unique needs of the operation in which it will be implemented and should be integrated into normal operations. Fatigue management is a shared responsibility between the organization and its employees, and all stakeholders should participate in order to provide the safest and healthiest working environment possible.

Jan 1, 2010

By L. Cornish, P. A. Olubambi, J. H. Potgieter

Four 22%Cr series duplex stainless steels alloys containing varying nickel contents of approximately 5, 7, 9 and 13% were melted in a vacuum induction furnace, hot rolled, solution annealed and water quenched. Their corrosion behaviour was investigated in sulphuric acid and sodium chloride solutions using a potentiodynamic polarization technique. Increasing nickel contents have appreciable influence on their corrosion behaviour. Polarization curves show similarities in the uniform corrosion behaviour of the alloys in the solutions and a significant difference in their pitting behaviour in chloride environments. Alloy 2209 generally exhibited highest resistance to uniform corrosion while 2213 displayed distinct and best pitting corrosion resistance. Their corrosion behaviour were attributed to the influence of nickel on phase modification, microstructural refinement, and the probably types of films formed in different environments. Keywords: Duplex stainless steel; Nickel; Microstructure; Phase modification; Corrosion

Jan 1, 2006

By M. Arlandi, J. C. Monge

In this paper, the finite element method is used to obtain deformations of a rock tunnel. More than 3,000 numerical simulations and calculations were carried out. The analysis of this results has allowed to achieve mathematical formulations and graphs, to obtain in advance support monitored displacements in tunnelling construction, so they can be predicted before excavation and supporting woks. The application of the presented formulations and charts will aid engineers to control tunnel monitoring, reducing decision time when problems occur. The analysis is limited to cases involving elastic behaviour of the terrain for tunnels of average to good quality in rock, and to excavation sections of average or smaller dimensions for road tunnels. The results show that, in all cases, mathematical expressions to obtain induced displacements around tunnel excavations, have similar pattern than Kirsch (1898) expressions for circular excavations. As corollary of the achieved results, a method to estimate in situ natural geostress ratio K0=sh/sv , by means of convergence measurements, is presented. In diesem Beitrag wurden die Verschiebungen eines Tunnels durch die Methode de Finiten Elemente berechnet. Mehr als 3000 numerische Simulationen und Berechnungen wurden ausgeführt. Die Analyse dieser Resultate hat es ermöglicht, mathematische Formeln und Grafiken zu entwickeln, die zur Voraussage der Verschiebungen in Tunnel dienen, auch unter Betrachtung der verschiedenartigen Abstützungen. So können die Verschiebungen vor den Erdarbeiten und dem Bau der Abstützung abgeschätzt werden. Die abgeleiteten Formeln und Grafiken werden vor allem einen grossen Dienst für Ingenieure bei der Mithilfe zu zeitsparenden Entscheidungen im Tunnelbau und bei der Tunnelkontrolle leisten. Die analysierten Fälle sind auf eine elastische Modellierung des Baugrunds beschränkt, sowie auf eine mittlere bis gute Qualität des Felsens und auf die Aushebung von Abtragungsabschnitten mittlerer oder geringer Grösse für den Strassenverkehr. Die Resultate zeigen, dass in allen Fällen die hergeleiteten Formeln zur Berechnung der durch den Tunnelbau verursachten Verschiebungen um den Tunnel die gleiche mathematische Struktur haben wie diejenigen von Kirsch (1898) für kreisförmigen Bodenaushub. Als Korollarium der ausgeführten Berechnungen wird eine Methode zur Abschätzung der vorherrschenden in situ Geospannungs-Verhälniss K0=sh/sv angegeben, die von den Messungen der Verschiebungen im Tunnel ausgeht. Dans cet article, la méthode des éléments finis est utilisée pour obtenir les déformations d’un tunnel creusé dans la roche. Plus de 3000 simulations numériques et calculs ont été effectuées. L’analyse de ces résultats a permis de définir des modèles mathématiques et des abaques afin de prédire, avant l’excavation et les travaux de soutènement, les déplacements auscultés pendant la construction du tunnel. L’application de ces modèles et abaques permettra donc aux ingénieurs de contrôler les déplacements durant l’auscultation du tunnel et de réduire le temps de décision lorsque des problèmes surviennent. L’analyse est limitée au cas du comportement élastique du terrain pour des tunnels creusés dans de la roche de moyenne a bonne qualité, et à de sections d’excavation de petites à moyennes dimensions pour des tunnels routiers. Les résultats montrent que, dans tous les cas, les expressions mathématiques permettant d’obtenir les déplacements induits autour des excavations de tunnel, présentent des similitudes avec celles de Kirsch (1898) pour des excavations circulaires. Comme corollaire aux résultats obtenus, une méthode pour estimer le rapport des

Jan 1, 2003

Palladium Alloys. E. M. Savitskii, V. P. Polyakova, M. A. Tylkina. Translated by: R. E. Howard. Published by Primary Services, New York, N.Y. 10012. $24.50. The output of palladium in the U.S.S.R. greatly exceeds the internal usage. The primary purpose of this 200 page volume is therefore to record details of fundamental researches on the properties of this metal with a view to expanding its marketability. Theoretical studies have revealed a number of alloys with great promise in electrical instruments and for the chemical industry. The success of these researches in the U.S.S.R. and in the U.S.A., resulted in the industrial usage of palladium exceeding that of platinum in 1957 and increasing its lead during the next decade. This volume is divided into three parts. Section I covers the mineralogy, extraction and the physical metallurgy of the metal. It records a considerable area where the resistance to corrosion of palladium equals that of platinum. Section II deals with the preparation and the properties of palladium in alloys and contains a comprehensive metallographic treatment of the many binary alloy systems. Section III is devoted to industrial applications. The 460 references which are quoted are mainly from the U.S.S.R. but otherwise have a world-wide coverage. H.B.

Book review Pearson, J. S. Ocean floor mining. Park Ridge (New Jersey), Noyes Data Corporation, 1975. 201 pp. NIM reports Report no. 308 A mineralogical study of gold particles in pulp residues from the Bracken Gold Mine. (7th Mar.,1968. Re-issued Oct. 1975.) Report no. 377 Examination of pulp samples, treated with cyanide, for coated gold.(7th Aug., 1968. Reissued Oct.1975.) Report no. 385 The determination of the nature of coatings on gold particles. (2nd Aug., 1968. Reissued Oct. 1975.) Report no. 452 The Purlex Process - a description of the pilot plant leading to the use of the process in South Africa. (13th Jan., 1969. Re-issued Oct. 1975.) Report no. 482 Review of work on the treatment of pegmatites. (9th Apr., 1969. Reissued Sep. 1975.) Report no. 1443 Gravity concentration tests on four samples from Tantalite Valley,S. W.A. (5th Jul., 1972. Re-issued Sep. 1975.) Report no. 1489 The breakage of S oderberg electrodes. (10th Nov., 1972. Re-issued Nov. 1975.) Report no. 1545 A mineralogical investigation of leach residues from the Blyvooruitzicht Gold Mine. (22nd May, 1973. Re-issued Nov. 1975.) Report no. 1583 Preliminary tests on winnowing for the recovery of mica. (12th Nov., 1973. Re-issued Sep. 1975.) Report no. 1652 The identification of diamonds from Premier, Finsch, and Jagersfontein Mines by statistical analysis of data obtained from instrumental neutron-activation analysis. Report no. 1723 The determination of zirconium and aluminium in zirconiumaluminium alloys. Report no. 1739 The determination of trace amounts of noble metals in sulphate media. Report no. 1771 The determination of silver, selenium, tellurium, antimony, tin, lead, and arsenic in anode sludges. Report no. 1772 A study of copper recovery by lime roasting and leaching. Corrigendum The Special Issue of Volume 76 of the Journal ('Recent Advances in Mineral Dressing, October 1975) should be corrected as follows. The South African Institute Of Mining And Metallurgy - Information On Membershlp The Institute was founded in 1894 as the Chemical and Metallurgical Society of South Africa. In 1904 it was reconstituted as the Chemical, Metallurgical and Mining Society of South Africa and in 1956 it became the South African Institute of Mining and Metallurgy. Die Suid-Afrikaanse Instituut vir Mynbou en Metallurgie - Inligting Oor Lidmaatskap Die Instituut is in 1894 gestig as die Chemiese en MIetallurgiese Vereniging van ::!nid-Afrika. In 190-1is dit omvorm tot die Chemiese Metallurgiese en Mynbouvereniging van Sllid-Afrika en in 1956 het dit die Suid-Afrikaanse Instituut vir Mynbou en l\Ietallurgie geword.

Jan 2, 1976

By A. K. K. Rompel, G. K. Chunnett

Introduction Structure appears to be of secondary importance to the Bushveld Complex when viewed from a distance. However, a closer look already reveals that large fault zones bound the Bushveld Complex. These fault zones are deep-seated crustal lineaments of continental magnitude such as the Thabazimbi-Murchison Lineament, the Johannesburg-Barberton Lineament, the Palala Fault zone and the Rustenburg fault. Furthermore, the Bushveld Complex is transected by large faults such as the Vlakfontein Fault, visible in the Pilanesberg, the Steelport Fault and the Laersdfrift Fault in the Eastern Bushveld, the Brits Graben, and a multitude of dyke generations (Figure 1). When pursuing structures on a project scale, the lack of outcrop, particularly in the western part of the Bushveld, is of no help for the exploration geologist. Consequently, the first dataset that needs to be considered is the Landsatimagery. Older Landsat TM 5 or newer Landsat ETM 7 will immediately reveal areas of outcrop for field visits, and, after further processing, indicate the geological units, in particular the platiniferous Critical and the Main Zone of the Rustenburg Layered Suite (Figure 2). Airborne magnetic surveys are the subsequent dataset necessary for any decent interpretation of the geology under the ?Black Turf? cover. Currently Anglo Platinum acquires aeromagnetic surveys with a flight height of 20 m and a line spacing of 50 m. These result in high-resolution imagery absolutely crucial for dyke delineation and dip modelling, stratigraphic layer detection, IRUP detection and possibly pothole discovery and fault delineation (Figures 3 and 4). However, the aeromagnetic surveys and the Landsat imagery reveal structures very much confined to the surface and may be hundreds of metres above the platiniferous reef horizons. This may lead to inaccuracies. When determining the underground structures for shaft sinking and mine planning, a 3D seismic survey is advisable. Too many shafts have been sunk in the Witwatersrand Basin for gold and in the Bushveld for platinum without sufficient information of the structure beneath. Recent 3D seismic surveys in the Bushveld have proven the technology and visualized the reef horizons and led to an interpretation of the underground structure (Figures 5 and 6). [ ]

Jan 1, 2004

By L. J. Gerber, O. D. Eniowo, L. D. Meyer, S. R. Kilambo

Artisanal and small-scale mining (ASM) operations continue to grow across sub-Saharan Africa and serve as a source of livelihood to many rural communities. Owing to safety, health, environmental, and social concerns, the occupation has been regarded as a menace in several sub-Sahara African countries. Recent studies in the field of ASM prescribe formalization as a way to tame its excesses while enhancing its potential. This paper explores the concept of formalization as it relates to ASM and how it is being affected by the funding situation. The paper seeks to address the question as to whether formalization of artisanal mining operations can achieve the desired results in view of the lingering credit constraints in this mining subsector. It is recommended that, as a way of extending the scope of formalization, focus should be placed not only on access to credit in ASM but also towards optimizing the creditworthiness of ASM firms, with the goal of improving the viability of the operations.

Mar 2, 2022