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By Didier Kasongo NYEMBWE

The paper circumscribes the base metal casting industry in Southern Africa. It essentially consists in the founding of copper and zinc alloys. The challenge related to the scarcity and the unaffordable quality patterns and dies faced by the industry is discussed. New manufacturing technologies for foundry tooling called Rapid Prototyping that can possibly be used to alleviate the above mentioned challenge are then presented and their benefits assessed.

Jan 1, 2007

By J. -C. Tricket, W. A. Düweke, S. Kock

The high-resolution three-dimensional (3-D) seismic reflection data acquired for Impala Platinum between 1998 and 2002 in the western Bushveld Igneous Complex form an integral part of Impala?s mine planning and development programme. These data are of sufficiently high quality to provide unprecedented 3-D models of the geological structure of the Merensky Reef and UG2Chromitite Reef, from which the mine deduces the size, geometry and distribution of mineable blocks. Conversely, the seismic data details zones of un-mineable ground caused by structural disturbances in the form of potholes, fault zones and pegmatoid intrusions. Furthermore, variations in dip and strike are well imaged, allowing the mine planners to optimize the mine design and layout. Current interpretation work is focused on enhancing the accuracy of these geological model seven further through the analysis of ?seismic trace attributes.? Preliminary testing on the Impala Platinum 3-D seismic volume has shown that attribute analysis has the potential to illuminate a number of geological reef disturbances that are otherwise ?invisible? in the original seismic time volume. Potential areas of improvement include inter alia: ?Improved definition of major fault zones ?Improved definition of zones of reef depression (?slumping?) ?Identification of reef terracing and/or reverse dip.. Keywords: 3D reflection seismics; Impala Platinum Ltd; seismic attribute analysis; Seismic Micro Technology (SMT); rock solid attributes; dip-azimuth; instantaneous phase and similarity.

Jan 1, 2004

By Gerhard Nel, Huziel Masiiwa, Marthie Kotze, René du Preez, Simon Donegan

Tati Nickel is currently operating a hydrometallurgical demonstration plant in Botswana, using the Activox® process developed by LionOre Technology, to produce nickel cathode and a cobalt salt from a sulphide concentrate. Cobalt is extracted using Cyanex 272. This reagent also extracts all the iron, aluminium, copper, zinc, and manganese from the nickel stream. Versatic 10 carboxylic acid is then used as extractant to recover nickel from the stream, separating it from calcium and magnesium, and upgrading it to provide a suitable advance electrolyte for nickel electrowinning. However, the selectivity of Versatic 10 for nickel over calcium is limited, and gypsum formation in the extraction circuit is a problem when it is attempted to maximise the recovery of nickel. Mintek has developed a synergistic system with Versatic 10 for improved separation of nickel from calcium and magnesium. Laboratory test work was conducted on the raffinate of the cobalt solvent extraction circuit to optimise the Versatic 10/Nicksyn? (Mintek synergist) system to be employed. Extraction and stripping parameters suitable for this stream were optimised in the laboratory and then applied on the demonstration plant. A commercial batch (0.5 tons) of Nicksyn? reagent was produced for the demonstration plant. The laboratory test work results and the demonstration plant performance are discussed in detail in this paper.

Jan 1, 2007

By R. M. Whyte

The complexities that exist in the nature of the basic feedstock to the metallurgical process call for a high degree of ingenuity from the extractive metallurgist in seeking the best possible treatment method for a particular ore. Drawing from personal experience the author presents four case studies that demonstrate the value of creative thinking in addressing the challenges typically encountered by the extraction metallurgist. It is concluded that creative expression most often occurs in response to a perceived strong need within an organization. By deliberately laying down meaningful challenges management can stimulate innovative thinking and achieve extraordinary results.

Jan 1, 2009

By E. R. Davis, R. J. Knott

The paper discusses some of the tools of management in the field of project control, especially in engineering. Project control includes planning and cost engineering, and involves various phases: the conceptual Design and Planning Phase, the Definitive Design and Capital Budgeting Phase, and the Implementation Phase. Each of these phases is discussed in in, together with the use that can be made of data banks, progress reports, and computer systems.

Jan 1, 1982

By RT White

For many years the concept of life cycle costing (LCC) was promoted for decision making in corrosion protection systems. Nevertheless, the application of LCC was limited. Input data was often sourced from suppliers and met with scepticism. As a result final analysis was often insufficiently rigorous to meet the needs of Project Managers in sound decision making. The need for expediency often resulted in non-optimal corrosion protection system specifications. With improved communications and the global reach of industries, case history data, based upon actual performance has been able to provide input to substantiate decision making. However, today?s focus upon sustainability whereby environmental, economic and even social aspects enter into decision making has extended LCC into Life Cost Analysis (LCA). In an LCA analysis energy and environmental inputs into systems are compared as part of an overall assessment. The development of Agenda 21 at the Rio summit of 1992 has challenged the countries of the world to look at sustainable development in every economic activity. This ranges from construction to mining to electricity production to automotive production, use and disposal. The protection of buildings, infrastructure and transport systems is part of the needs of sustainable development. Zinc based corrosion protection has been an important part of the arsenal of the corrosion protection industry. This paper will highlight the use of LCC and the development of LCA with reference to the use of zinc based protection systems in a number of important industries.

Jan 1, 2006

By Y. Y. Jiao, J. G. Cai

To investigate the dimensional effect on shock wave propagation in jointed rock masses, a 2-D and a 3-D calculation of a site test are performed respectively by using Discrete Element Method, the simulated results are compared with test data. It shows that, in modelling shock wave propagation and attenuation in jointed rock masses, when the explosive along explosion chamber is long enough and the joints are dense enough or uniformly distributed, the model can be considered as plane-strain problem, 2-D results are good enough to fit with test data. 2-D modelling, with much more details of rock masses taken into account, can be applied to make critical engineering judgements instead of 3-D modelling in some cases.

Jan 1, 2003

By L. A. Cornish, L. H. Chown, S. N. Prins, R. Süss, L. Glaner, A. Douglas

Platinum-based alloys are being developed for high temperature and special applications for good corrosion and oxidation resistance. The microstructures are similar to those of nickel-based super alloys, and comprise ~Pt3Al particles in a Pt-based matrix. After assessing binary alloys, the best candidate system was found to be Pt-Al. Testing and selection of alloys based on Pt-Al were undertaken, where the ternary additions comprised Ru, Cr, Ta, Ir and Ti. As well as phase characterization work, mechanical and oxidation tests were undertaken. The best alloys were found to be Pt-Al-Cr and Pt-Al-Ru. However, the volume fraction of the ~Pt3Al was only around40 per cent instead of the ~70 per cent found in Ni-based super alloys. To increase this, trials were conducted on a range of Pt-Al-Cr-Ru alloys, the optimum composition being Pt80:Al14:Cr3:Ru3.Currently, further additions are being made to the quaternary alloys to change selected properties. As well as developing the alloys themselves, another part of the project is to compile a thermodynamic database using Thermo-Calc?. Phase diagram work has been undertaken so that the results can be input to Thermo-Calc? so that the descriptions of the phases can be optimized. The final database will allow the phases and compositions of selected alloys to be derived, thus predicting the alloys? components without necessarily undertaking further experimental work. This will aid the development of the alloys and will be a useful tool to the final developers of the alloys. Good agreement with experimental data has been observed, which is very encouraging for usefulness of the database. Keywords: platinum-based alloys, intermetallic compounds, high temperature

Jan 1, 2004

By T. C. Alex, K. M. Godiwalla, R. K. Jana

Manganese nodule, available in ocean beds, is a potential resource of the future for copper, nickel and cobalt. Recovering only these metals, containing less than 3% by weight, will result in the generation of large amount of residue. In addition to the material losses, several environmental and ecological problems arise out of this. The present study has been aimed at reducing the environmental and ecological problems associated with massive generation of this residue together with utilization of the resources. Presence of ~ 20% manganese and ~16% silicon in the residue has prompted us to check its suitability as a raw material for silicomanganese production. Lower manganese content and lower Mn/Fe ratio of the residue than that required for silicomanganese production has been corrected in this study by suitable blending. The efficacy of blending and its thermodynamic aspects using FACTSAGE software are discussed. The studies conducted indicate viability of bulk utilisation of the residue through silicomanganese production and thereby reducing the burden on environment to a great extent.

Jan 1, 2007

By R. Romano, E. Montalar, J. B. Serón

The SMR geomechanics classification system (adaptation of RMR for slopes) is reviewed with data from 87 actual slopes in Valencia. In a research project, SMR has been applied by a GIS system, as a method to forecast stability problems in future road construction. As a result of this work a methodology for GIS application has been developed. On revient sur la classification geomechanique SMR ( une adaptation du RMR pour talus et pentes) avec les dates de 87 talus existant autour de Valencia. Dans le cadre d’un projet de recherche SMR a été appliquée, avec un système GIS, comme méthode de prévision de stabilité problèmes dans la construction de futures routes. Une méthodologie pour l’application du GIS a été développe. Das Geomechanische Einteilungssystem SMR (eine Anpassung des RMR an Böschungen) wird an Hand der Daten von 87 Böschungen im Gebiet von Valencia überdacht. In einem Forschungsprojekt wurde das SMR in einem Geographischen Informationssystem (GIS) als Methode zur Vorhersage von Stabilitätsproblemen bei zukünftigen Straßenbauprojekten eingesetzt. Das Ergebnis dieser Arbeit ist die Entwicklung einer Methodologie für die GIS-Anwendung

Jan 1, 2003

By John M. L Lewis, Antoine F. Mulaba-Bafubiandi

In the irradiation of ore particles by microwave energy preferential absorption of this energy occurs in minerals having specific dielectric properties (Bradshaw, 1999). This leads to a selective heating of the various components of within the ore particle matrix. The result is a differential thermal expansion of such components and the resulting induced stresses become ideally concentrated at mineral grain boundaries (Kingman et al., 2000). Dependent upon the relative composition of absorbent, opaque and reflective components this may lead to enhancement of the inter-granular fracture of the ore particles in the initial comminution process (Fandrich et al., 1997). The potential is thus a greater proportion of free mineral grain within the fractured ore particle that may lead to improvement in subsequent mineral separation processes. As the composition of the ore dictates the result of such a treatment (Kingman et al., 2000) it is essential to evaluate the response of each ore sample on an individual basis. This paper reports on results obtained from two ore samples: the one being the zinc ore from the Black Mountain mine (South Africa) and the other a pre-concentrated sample of handpicked cobalt?copper mixed oxide ore from the Gecamines (DRC). The equipment and methods used to simulate the comminution of the samples and evaluate the level of the value liberation will be described along with the results obtained. Using King (1975), Kanellopoulous and Ball (1975), and Gungor and Atalay (1998), a comparison between the behaviour upon microwave irradiation of sulphide and mixed oxide ores leads to conclude that while the technique (i.e. microwave irradiation) is appropriate to the zinc sulphide ore, it does not seem to lead to exceptional results for the oxide.

Jan 1, 2005

By Christian Heili

In 1991 the Government of the Republic of Zambia passed legislation providing for the privatisation of Zambia Consolidated Copper Mines Limited (ZCCM). The newly formed Mining Companies, established after nearly a decade of difficult and protracted negotiations on such matters as, cash at close; retained percentage interest by ZCCM; equity investment; future investment commitment and tax concessions, were faced with great internal challenges and a harsh external environment. There was a convergence of a number of negative forces that had and will continue to have an impact on the mining environment in Zambia. The most crucial of these being, the competitive pressures of the global economy, fluctuating copper price and the prevailing HIV/AIDS pandemic. In the short period after privatisation, the Industry has seen the collapse of Binani Industries (Luanshya Mine), the withdrawal of Anglo America Corporation from Konkola Copper Mines Plc and the disposal of Chambishi Cobalt and Acid Plants by Anglovaal Mining Ltd. The objective of this paper is to provide a theoretical and practically researched foundation, which may be used to assist Zambian Mining Companies in making informed decisions on the issue of Strategic Outsourcing and the degree to which this may support the successful and sustainable growth of the Zambian Copper Mining Industry. If judiciously implemented, Strategic Outsourcing has the potential to generate a practical business valuation and process to assist Mine Management in the achievement of their business goals and consequently the return on investment to their Shareholders.

Jan 1, 2005

Historically, mine ventilation practices as it was referred to then and which was enforced by legislation of those days, focused primarily on the conditions in the working place and little attention given to actual exposures of workers to contaminants in the working environments. With the advent of the Leon Commission of Inquiry into Safety and Health in the South African Mining industry in 1994, findings in the report indicated that more attention should be given to occupational health of workers. The upshot of this report resulted in the promulgation of the new Mine Health and Safety Act (MHSA) with certain sections of it devoted to all the aspects of occupational medicine and occupational hygiene. This paper describes the present situation with regards to statistics on occupational hygiene performance and compensation paid out to persons who have contracted occupational diseases, as well as the way forward in terms of legislation implemented in September 2002 on the chronic and acute issues affecting the mining industry in SA.

Jan 1, 2003

By C. G. Anderson

Throughout the world, there are many orebodies or materials which have significant value but also contain arsenic, antimony, and mercury. As regulations on the transport, exposure, disposition and emission of these elements have become more stringent; it has become increasingly more difficult to derive the values from the resources. This paper outlines the fundamentals of alkaline sulfide hydrometallurgy and its successful application to arsenic, antimony and mercury bearing ores, concentrates, by-products, and other materials.

Jan 1, 2008

OPENING SESSION Session Chairpersons: Dr. P.P. Jourdan & Dr. L.A. Cramer Transformation to Tackle the Challenges Facing the Ferro Alloy Industry in the Next Decade R.J. Linnell Electricity Supply in SA ? A 10-Year View T.S. Gcabashe IDC as the Catalyst for Growth in the South African Ferroalloys Industry J. Kriek Development in the Global Stainless Steel Industry V. Muñoz CLOSING SESSION Session Chairpersons: Mr. R.J. Linnell & Dr. O.F.R.A. Damm The Health of Vanadium T.E. Jones Steel Raw Materials - Nickel, Chrome, Stainless Steel Scrap and Manganese H.H. Pariser

Jan 1, 2004

By L. I. Gonzalez de Vallejo

SRC rockmass classification have been applied to 25 tunnels in Spain and Italy, for which it was found that much heavier supports than those estimated by the RMR index were required. SRC and RMR indices and other relevant geomechanical data were obtained during the site investigation and construction stages. Data corresponding to in situ stress measurements, analysis of tectonic structures, and instability problems arising during construction were used to asses the state of stress. The relationship between tunnel section convergence and the SRC and RMR indices was also analysed. Support measurements based on SRC and RMR classification were compared with those actually used during construction. These analyses indicate that for most of the tunnels examined, supports estimated using the SRC were much closer to those actually installed than those predicted by the RMR index. Bei der Verwendung des SRC-Systems zur Klassifizierung des Gesteins als Baugrund für 25 Tunnel in Spanien und Italien wurde festgestellt, dass viel schwerere Abstützungen benötigt wurden, als wenn die Beurteilung anhand des RMR-Systems angefertigt würde. Die Klassifizierung anhand des SRC- und des RMR-Systems, sowohl als auch andere wichtige geomechanische Daten wurden während des Ablaufs der Erkundungen und der Bauausführung gewonnen. Die Resultate der Messungen der Spannungen vor Ort, die Analyse der tektonischen Struktur und die Stabilitätsprobleme während der Bauausführung wurden dazu verwendet, um den im Felsgrund vorherrschenden Spannungszustand zu definieren. Das Verhältnis der Messungen der Tunnelkonvergenz zu dem SRC- und RMR-Index wurde auch analysiert. Die durch das SRC- und RMR-System vorhergesagte Grösse der Abstützung wurde mit der Grösse der Abstützungen verglichen, die am Bau letztlich verwandt wurden. Diese Vergleiche zeigen, dass für die meisten der studierten Tunnel die Vorhersage der Abstützungen, die anhand des SRC-Systems angefertigt wurden, viel näher der wirklich verwendeten waren als die Vorhersage anhand des RMR-Systems. SRC rockmass la classification ont été appliqué à 25 tunnels en Espagne et l'Italie, pour laquelle il a été trouvé que des appuis beaucoup plus lourds que ceux évalués par l'index RMR ont été exigés. SRC et des index RMR et d'autres données geomechanical appropriées ont été obtenu pendant l'enquête de site et les étapes(scènes) de construction. Les données correspondant aux mesures de stress(d'accent) in situ, l'analyse de structures tectoniques et des problèmes d'instabilité surgissant pendant la construction ont été utilisées aux ânes(culs) l'état de stress(d'accent). Le rapport entre la convergence de section de tunnel et le SRC et les index RMR a été aussi analysé. Les mesures d'appui basées sur SRC et la classification RMR ont été comparées avec ceux en réalité utilisés pendant la construction. Ces analyses indiquent que pour la plupart des tunnels examinés, les appuis évalués utilisant le SRC étaient beaucoup plus proches de ceux en réalité installés que ceux prévus par l'index RMR.

Jan 1, 2003

By A. F. Collings

The processing of heavy mineral concentrates can be enhanced by the use of power ultrasound to clean their surfaces of oxidation products and fine coatings, mainly through the large, but very localized forces, produced by cavitation. Results are presented of the application of power ultrasound to remove coatings from the surfaces of mineral sand concentrates in order to improve the sharpness of their high-tension separation and, in some cases, the quality of the low iron components such as zircon. Improvements of 10–15% in recovery and up to 20% in grade compared to unsonicated material were achieved in a single stage laboratory high-tension separation. Cavitation also ensures that a fresh, clean surface is presented to leachants during the leaching of suspended solids. At the same time, the effect of cavitation and the shearing effect of the sound wave passing over the solids ensure that the saturated boundary layer is kept to a minimum if not completely removed. This application of power ultrasound helps to speed up leaching processes as applied to the removal of excess alumino-silicate contaminants in some ilmenite. Keywords: Ultrasound, power ultrasound, heavy minerals, processing.

Jan 1, 2003

By J. Lux, B. Clermont

Magotteaux, with the co-operation of Anglo Platinum, has erected a fully instrumented pilot plant at Frank concentrator, which is being used to study the influence of a variety of grinding parameters. This paper will discuss only the influence of mill speed and pulp density on secondary stage grinding. A Ø0.82 x1 m open circuit mill was used with reclaimed Merensky tailings as feed. The conclusions apply to this pilot plant but further investigation needs to be done to verify whether the same trends will be applicable to a large industrial-scale mill.

Jan 1, 2004

By D. Nyembe, B. Mamba, Antoine F. Mulaba-Bafubiandi

Copper and cobalt are generally electro-won from their aqueous sulphate solutions. After optimised leaching of their ores, concentrates or calcine bearing minerals, the leachate is clarified and suitably purified prior to the electrolytic extraction of the metal of pursuit (Pearcy, 2006). Solvent extraction (SX) using appropriate organic solvents and ion exchange (IX) with relevant resins are known purification processes used for copper and cobalt recovery (Stanely, 1970).As zeolites in general and natural zeolites in particular, demonstrate ion exchange properties (Korkuna et al., 2005), an attempt has been made to use Southern African natural clinoptilolite in the recovery of copper and cobalt from their aqueous sulphate solutions. Initially, synthetic Co and Cu solutions were prepared. Preceded by laboratory ore leachate, plant solutions are to be used. AAS, XRF, XRD, Mossbauer spectroscopy and BET were characterization techniques used. Natural clinoptilolite was used as-received as well as acid activated; and cobalt and copper extractions were performed at room temperature.

Jan 1, 2007

By J. W. van der Merwe, A. S. Bolokang, M. J. Phasha, V. J. Matjeke, C. Moopanar

"Excessive wear rates on railway wheels can result in rolling-stock derailments. If wear is detected early the possible derailments can be prevented by prematurely replacing wheelsets, although the inventory cost and maintenance downtime remain a challenge. In the current study, wheels were introduced and monitored in-service for two years to investigate the cause of excessive wear rates. The wear rates and stresses were calculated for the wheels suitable for a maximum load of 26 t per axle. Microstructural and mechanical properties were analysed. As expected, the general microstructure of all the wheels tested was pearlitic. Although all the wheels complied with the tensile strength requirements, stress calculations confirmed material distortion on excessively worn wheels whereas trial wheels revealed yield strength exceeding the yield criterion. High wear rates observed on the wheels were a result of low yield strength relative to the load per axle. The typical wear mechanism found was due to a combination of rolling contact fatigue and abrasive brake wear. Despite compliance of the wheels with existing requirements regarding material and mechanical properties (hardness, ultimate tensile strength), it is recommended that the yield strength must also be taken into consideration as a critical parameter.IntroductionRailway wheels are used to support the wagon mass and guide the wagon along the tracks (Park, 1974). The wheels and rails must be able to tolerate the applied tangential forces in order to effect wagon dynamic performance and reduce material deformation (Ghidini et al., 1994; RSE_TE_SPC_0045, 2011; AAR M107/M 208 Specification, 2011. Over the past ten years, the South African coal wagon maintenance depot has experienced excessive hollow wheel wear rates on the heavy haul line wheels. The maximum load of Jumbo wagons on the coal line is 104 t, or 26 t per axle. Although the maintenance intervention cycle for wheelsets was two years, between February 2011 and August 2012 some wheels experienced excessive hollow wear. Hollow wear is regarded as wear exceeding 2 mm on the central portion of the wheel tread (RSE_TE_SPC_0045, 2011). This happened despite the fact that these wheels were manufactured and certified according to the requirements of AAR M107/208 standard for carbon steel wheels (AAR M107/M 208 Specification,. 2011) and the local wheel RS/ME/SP 021 standard specification (RS / ME / SP / 021 REV 5 (2013). The AAR standard only specifies a minimum hardness as a required mechanical property and the local standard specifies hardness and minimum tensile strength only. In general, an increase in hardness will improve the rolling/sliding wear resistance of steel. This relationship of hardness and wear resistance was found to be true only in a situation where solid and similar alloys are in contact (Singh, Khatirkar and Sapate, 2015). The sliding wear resistance of a material is usually estimated using Archard’s equation (Liu and Li, 2001)."

Jan 1, 2016