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By Gordon Chunnett, Ron Sheets, David Grant

[Power-Point Presentation]

Jan 1, 2005

By F. S. A. de Frey

The main users of computerised financial evaluation tools in the mining industry are the mining investment analyst, the mine manager together with his financial manager and the mining student (undergruadate and post-graduate). The mining investment analyst's needs mainly centre around the-micro and macro aspects affecting the mining industry in general. The mine manager needs a tool to assist him with the planning, reporting and controlling of production, costs, efficiency, productivity and cashflow. For the mining student studying Financial Evaluation, the main need is for a computer program which will assist him in learning the basics of the subject. This paper concentrates on the needs and objectives of the course Financial Mine Evaluation, the approach to which is presented. Emphasis is placed on the practical computing sessions and the role of the FCS-EPS package as a training tool.

Jan 1, 1987

Since 2001, the Hybrid Stress Blast Model (HSBM) project members have developed a software suite to model the complete blasting process from non-ideal detonation to muck pile formation. To preserve the physics and improve solution time, the breakage engine uses a combination of analytical models and 2D axisym-metric finite differences to model near-field crushing, coupled to 3D discrete lattice fracturing and distinct element numerical methods to model throw and muck pile development. The model has been validated by comparison with laboratory and field tests in kimberlite. Multiple blasthole simulations are used to demonstrate how changes to blasting parameters can influence downstream efficiencies. Case studies of wall control blasting show that the presplit design must balance the two opposing effects of increased damage with increased charge and decreasing attenuation of the seismic waves with decreasing charge. Modelling of decoupled explosives needs further development. Reducing the charge towards the back of the trim blast results in a much more significant decrease in back damage than altering the timing. The model demonstrates how separation along the weaker planes in a jointed rock can coarsen the fragmentation, leading to inefficient beneficiation, and extends the damage to a distance of at least twice the burden behind from the blasthole, severely compromising the wall stability.

Jan 1, 2012

By P. J. Kinver

This paper deals with the development of backfilling methods and systems at the Broken Hill orebody of Black Mountain Mineral Development Company (Pty) Limited, at Aggeneys in the north-western Cape Province. Production started in 1979, being confined to large diameter blasthole stoping methods in the upper, steeply dipping areas of the orebody. This blasthole reserve is now depleted and the production tonnage, 100000 tons per month, is produced from eight cut and fill stopes in the flatter dipping areas of the orebody. The fill methods of the blasthole stoping area evolved prior to the pillar extraction are briefly discussed together with the resulting experiences gained that enabled virtually 100% extraction to be achieved. The original cut and fill mining used costly hydraulic cemented fill; this was replaced partly by unconsolidated river sand and later by dune sand which occurs in abundance. The paper describes the planning, research work and commissioning of a cycloning plant that now enables dune sand to be used successfully as an unconsolidated hydraulic fill. The development of drainage, placement and control methods are also reviewed.

Jan 1, 1988

By P. Goosen

The paper presents a basic summary of the approach to hydraulic scale-model tests as may typically be applicable to slurry flow situations. A case study is presented illustrating how hydraulic scale-model tests can be of significant benefit in evaluating the performance of novel or unproven slurry handling equipment. In this case the equipment tested was a fan-shaped expansion piece used to spread the discharge from a launder over the full width of a dewatering screen. The tests showed that the device did indeed distribute the slurry flow both in terms of volume and solids mass, but not perfectly uniformly. Unfortunately the equipment was not taken beyond the model test phase. The scale-model test approach did, however, prove to be very useful as it is considered to have provided a good indication of the expected performance of the full-size unit. Significantly, this was achieved at very low cost compared to the cost of installing the device into the proposed plant and having to later change it out for an alternative or live with the less than optimal performance. The paper illustrates the value that can derive from applying hydraulic scale-model testing techniques to evaluating the performance of new or unusual slurry handling equipment. There is particular value in situations that do not lend themselves to numerical modelling.

Jan 1, 2007

By Timo Niitti, Sami Grönstrand

n today's marketplace with high metals prices, many operations are faced with the challenge of improving recovery and at the same time maximizing availability. New operations under feasibility studies have the same requirements, with the additional need for ever higher capacities. Economies of scale have proved a vital competitive advantage in the game of ore dressing. Flotation is the most widely used method for extracting valuable minerals from ore - despite its mature age of 100 years. Customer demand has driven the development to increasing cell sizes, and in most cases, this has brought the advantages of both lower capital expenditure and lower operational and maintenance cost. The challenge of scale up, however, is to meet the metallurgical performance requirements in the larger volumes. The paper outlines recent trends and developments in flotation technology, and presents new solutions designed to address the needs for increased capacities as well as improved performance. Whether the goal is to improve existing operations or to scale up new equipment, computer aided tools are playing a key role in shortening the development cycle and reducing costly trial-and-error tests in full scale. Using the new tools and validation thereof will be outlined, as well as the development principles behind the new solutions. Plant results and experiences with the new developments are presented and discussed in several cases around the world.

Jan 1, 2007

By H. D. Mtegha

The Southern African Development Community (SADC) aims to harmonize mineral policies and regulatory regimes in the minerals sector. This paper provides a review of the progress made towards harmonization of mineral regimes in the region. It singles out only the mining fiscal environment, as this is normally one of the key issues of interest to potential investors as well as the host state. Indications are that the region is slowly progressing towards a more harmonized approach, and there is evidence that the ?race to the bottom? has been prevented, which is the basis for an integrated mineral sector that the region aspires to.

Jan 1, 2011

By J. Dvorácek

Mine water poses a significant problem in lignite coal mining. The drainage of mine water is the fundamental prerequisite of mining operations. Under the legislation of the Czech Republic, mine water that discharges into surface watercourse is subject to the permission of the state administration body in the water management sector. The permission also stipulates the limits for mine water pollution. Therefore, mine water has to be purified prior to discharge. Although all mining companies operate mine water treatment plants, there is hardly any utilization of the final effluent. The high expenditure involved in the more sophisticated methods of mine water treatment has fuelled the search for the commercial utilization of the effluent.

Jan 1, 2012

By C. Van Rhee

In dredging practice sand is eroded at very high flow velocities using water jets. The existing pick-up functions overestimate erosion. By taking the permeability into account conventional pick-up functions can be made suitable for high velocity erosion. This can be achieved by modifying the critical Shields parameter. The procedure is demonstrated using the pick-up function of Van Rijn. The theory is compared with experiments and agreement is good.

Jan 1, 2007

By M. K. Matthews

The use of backfill has important environmental control implications which, although frequently overlooked, can be both beneficial and problematical. Where backfill is widely used, the reduction in stope heat load and improved air utilization influence the overall mine ventilation and refrigeration requirements significantly. A programme of work examining in detail all the environmental consequences of backfilling is currently underway at the Environmental Engineering Laboratory of the Research Organization of the Chamber of Mines. This paper gives an overview of the work and presents some findings. In so doing, the environmental implications to be considered when backfilling are highlighted.

Jan 1, 1988

By M. H. Moys

A method of estimating the percent solids in the discharge from a grinding mill is described and tested on both pilot and industrial scale. It involves the use of energy and mass balances around the mill discharge sump, requiring measurements of the flowrate and density from the sump together with temperatures of all streams flowing to and from the sump. Accurate estimates of the dynamic variation of mill discharge percent solids are made available, provided that occasional manual sampling of the stream is done to cope with drift in instrumentation. The use of a computer in this application was essential; the various advantages associated with its use are discussed. It is anticipated that this estimate of discharge density can be controlled at a set point by manipulation of the water fed to the mill, resulting in significant decreases in specific power consumption and media consumption.

Jan 1, 1987

By B. Sergeant

Any study of the contentious subject of nationalization can ultimately be reduced to a sombre analysis of the simultaneous, and very different, interests of capital, labour, and government. Each of these interests attempts to maximize its objectives, subject to checks and balances provided, in an ideal system, by a country's executive government, legislature, and judiciary. Where even one of the three interests goes out of control, the consequences can be disastrous. The case histories show that when this occurs, the most common culprit is government, or its proxy, such as a dictator. At the other extreme, the case studies indicate that the optimum outcome occurs when capital, labour, and government are 'ring fenced' from each other: each enjoys its rights, but is also subject to duties. 'Conflicts of interest' between the three entities are ideally avoided to the maximum possible extent. The case studies include several salient instances from both the DRC (Gécamines, La Générale des Carrières et des Mines) and Zambia, along with Ghana and Chile. Further instances are examined in South Africa (gold), India (Coal of India), Brazil (Petrobras), Venezuela (Petróleos de Venezuela), Sweden (Luossavaara-Kiirunavaara Aktiebolag), Mauritania (Société Nationale Industrielle et Minière), Norway (Norsk Hydro), Botswana (Debswana), and Namibia (Namdeb). The article concludes broadly that South Africa's minerals sector is not ready for nationalization.

Jan 1, 2013

By E. Dermietzel

The fundamental ideas of Computer Aided Lignite Mining (CALM) with respect to hardware and software used at Rheinbraun are explained and outlined in detail. The computers used in the main data processing department and in the different departments in the mines are described. Special emphasis is laid upon the network connecting the computers at different places for data-exchange. Concerning technical applications, the main facilities of CALM are deposit and pit modelling, complex geomechanic computations and mass calculations, data recording from the production process in the pits and refining plants, and detailed information and planning systems for water management and mining equipment. Concerning administrative applications, the main facilities of the software are the accounting system with cost controlling and planning, the materials management system with stock control, forward planning and computer supported order procesing, a system for the administration of property within and surrounding the mines, and systems for personnel administration and payroll. The various software systems developed for these application and the influence of data processing technique, such as data base management and the interconnection of data processing systems, are demonstrated.

Jan 1, 1987

By S. A. Forrest, B. Clarke

Trends in PGM demand?The conference paper will cover a concise analysis of demand trends, which will include the major PGM end-use sectors (autocatalysis, jewellery, glass, petroleum, nitric acid, medical/dental) and will touch on the investment sector. Reference will be made to environmental legislation affecting global emission standards, trends in PGM loadings and the substitutability of platinum and palladium in this end-use sector. Observations will also be made on the jewellery sector, and the development of Chinese and Japanese demand. Trends in primary and secondary PGM supply?Similarly the paper will summarize historic and current global mine supply and primary production trends for PGMs, referencing recent expansions, their deliverability, and other projects coming on line. Consideration will be given to the grade and geology of PGMs worldwide and metallurgical developments. PGMs produced as by-products of base metal production and early PGM recycling estimates will also be appraised. In order to gain a wide-ranging appreciation of the industry?s long-term cost trends of producing virgin PGM metals, the paper will look at the cost and profit dynamics of global production on a regional basis (Western Bushveld, Eastern Bushveld, Northern Bushveld, Zimbabwe, USA, Canada and Russia). Extrapolating tomorrow?s PGM market and forecasting metal prices?Based on established industry trends and market practices Stephen Forrest will conclude by unveiling a variety of thought-provoking extrapolations of today?s and tomorrows platinum, palladium and rhodium markets to conference delegates. Importantly, having highlighted major developing PGM market trends in end-use (specifically on the elasticity of demand to high metal prices), primary and secondary PGM supply trends, in addition to presenting a carefully reasoned forecast of industry supply costs and margin trends, Stephen Forrest will conclude by estimating long-range PGM metal price trends. Other relevant market factors including industrial production, global currency rates and regional political factors will be deliberated.

Jan 1, 2006

By M. Pötsch, W. Schubert, A. Goricki

Geological and geotechnical data are essential for the design of tunnels. To determine the rock mass behavior and the support of a planned tunnel excavation a consistent method for rock mass characterization and excavation and support determination has been developed. Probabilistic data processing with analytical methods is used for the quantification of the procedure and allows an evaluation of the applicability and the technical risk of different excavation and support methods. The sensitivity of the procedure on selected input parameters is highlighted in a parametric study. Finally an application of the procedure illustrates the use of the described method of probabilistic excavation and support determination for tunnels. Des données géologiques et géotechniques sont décisives pour la planification d’un tunnel. Pour la détermination du comportement des strates, le choix du soutènement et de la méthode de progression une description compréhensible de la montagne a été développée. À l'aide d'un traitement de données probabiliste, la procédure proposée est transposée quantitative sur une base de méthodes analytiques. De cette manière l'évaluation des méthodes de construction et la détermination du risque technique deviennent possibles. La sensitivité de la procédure de différents paramètres d'entrée est représentée dans une étude de paramètre. Pour finir, l'application de la procédure décrite est montrée à l’aide d'un cas pratique. Geologische und geotechnische Daten sind entscheidend für die Planung von Tunnels. Für die Ermittlung des Gebirgsverhaltens und der Festlegung von Ausbruch und Stützung wurde ein nachvollziehbarer Ablauf der Gebirgsbeschreibung entwickelt. Mit Hilfe von probabilistischer Datenverarbeitung auf Grundlage analytischer Methoden wird die vorgeschlagene Prozedur quantiativ umgesetzt. Dadurch werden die Bewertung von Baumethoden und die Ermittlung des technischen Risikos ermöglicht. Die Sensitivität des Verfahrens von einzelnen Eingangsparametern wird in einer Parameterstudie dargestellt. Abschließend wird anhand eines Beispiels die Anwendung des beschriebenen Verfahrens gezeigt.

Jan 1, 2003

By F. Lanaro, K. Röshoff, R. Christiansson, L. Jing

This paper presents the results of a project for developing a methodology for empirically determining some of the mechanical properties of the rock mass at the Äspö Hard Rock Laboratory, Southern Sweden. Using the equations available in the literature, the deformation modulus, friction angle, cohesion and unconfined compressive strength of the rock mass were estimated. A comparison of the results using different classification methods (Q, RMR, GSI, RMi, Ramamurthy’s) was made to estimate the range of variations in the mechanical properties with the considerations of: i) the quality/quantity of the geological data; ii) the technique for partitioning of the rock mass into homogeneous domains; iii) the sensitivity and subjectivity of the empirical methods; and iv) the need for validating the empirical methods against a test case. Cet article présente les résultats d’un projet visant à établir une méthodologie, pour déterminer, de façon empirique, les propriétés mécaniques de la masse rocheuse. En utilisant les corrélations disponibles dans la littérature, quelques-unes des propriétés de la masse rocheuse ont pu être déterminées (module de déformation, angle de friction, cohésion, force de compression illimitée). Une comparaison des résultats obtenus par différentes méthodes (Q, RMR, GSI, RMi, de Ramamurthy) a permis d’établir une échelle de variations des propriétés mécaniques et de formuler une série de recommandations concernant : i) la qualité/quantité des données géologiques ; ii) la technique de partition de la masse rocheuse dans des domaines homogènes ; iii) la sensibilité et la subjectivité des méthodes empiriques ; iv) la nécessité de valider les méthodes empiriques à l’aide de nouvelles études de cas. Dieses Paper präsentiert die Ergebnisse eines Projekts mit dem Ziel, eine Methodik für die empirische Festhellung von mechanischen Eigenschaften im Gesteinmassiv zu etablieren. Durch Verwendung der in der Literatur zugänglichen Korrelationen, wurden einige Eigenschaften des Gesteinmassivs festgestellt (Entstellungsmodul, Reibungswinkel, Kohäsion, unbeschränkte Kompressionsstärke). Ein Vergleich der Ergebnisse unterschiedlicher Methoden (Q, RMR, GSI, RMi, Ramamurthy’s) wurde durchgeführt und dies erlaubte die Feststellung der Variationsskala von den mechanischen Eigenschaften, sowie eine Reihe Empfehlungen für: i) Qualität/Quantität der geologischen Dateien; ii) die Technik für Teilung des Gesteinmassivs in homogene Domäne; iii)die Empfindlichkeit und Subjektivität der empirischen Methoden; iv) das Bedarf die empirische Methoden gegen neue Fallgeschichten zu validieren.

Jan 1, 2003

By T. Moyo

"The oxidative leaching of chalcopyrite in ammoniacal solutions has been evaluated using electro-analytical techniques and controlled bulk leaching studies. The anodic dissolution process has been established to be a sevenelectron transfer process under nitrogen in ammonia–ammonium sulphate solutions and ammonia–ammonium carbonate solutions, which suggests that the sulphur is oxidized to thiosulphate and the copper and iron released as Cu+ and Fe2+ in these systems. The deportment of Fe2+ and S2O3 2- is affected by choice of the ammonium salt used in the leaching process. In the perchlorate salt, only five electrons are transferred, supporting formation of different sulphur species as proposed for the sulphate and carbonate salts. Scanning electron microscopy and energydispersive spectroscopic analysis of the mineral surface after leaching indicate presence of an iron–sulphur surface layer completely free of copper in the sulphate system, an iron-rich surface layer in the perchlorate solutions, and absence of surface layer build-up in carbonate solutions. XRD analysis of a bulk leach residue from leaching in ammoniaammonium sulphate solutions showed the surface layer to be mostly amorphous (90%). The crystalline content (10%) is composed of 95% polymorphs of anhydrous iron oxide hydroxide FeO(OH). Choice of ammonium salt and the hydrodynamic environment of leaching have been shown to influence the presence or absence of the surface product, as well as its nature. IntroductionHydrometallurgical processes for copper extraction provide a viable route to recover the metal from mixed and low-grade ores, as well as overcome the environmental challenges faced by the traditional pyrometallurgical processes. Chalcopyrite is not only the most abundant of the copper sulphides, but also the most stable, making it recalcitrant to hydrometallurgical processes. Hence, hydrometallurgical processing of chalcopyrite continues to be an attractive area of research due to the vaguely understood surface chemistry of the mineral in different aqueous media. Different routes for hydrometallurgical treatment of chalcopyrite can be followed. These include thermal treatment prior to leaching, direct leaching and direct electrochemical leaching (Venkatachalam, 1991). Direct leaching of chalcopyrite can be carried out in various solution systems, as reviewed by Roman and Benner (1973) and Venkatachalam (1991). Ammoniacal solutions are attractive and effective lixiviants that form stable amine complexes with some base metal cations while rejecting iron. Leaching of chalcopyrite in ammoniacal solutions in the presence of an oxidant is possible due to the stabilization of copper (I) and copper(II) by ammonia at elevated pH levels. In oxygenated ammonia solutions, it has been suggested that chalcopyrite dissolves according to Equation [1] (Beckstead and Miller., 1977a):"

Jan 1, 2016

By D. Vogt

"Rock has been cut in the process of mining since before the invention of explosives. Today, we seek to return to cutting to reap the benefits of continuous operations for South African underground hard-rock mines, to improve speed of access to the orebody, and to improve the efficiency of mining operations.Development of new technology fits within a framework of engineering knowledge. By understanding the characteristics of the rock, the tools we use to cut it with, and the history of mining and rock cutting, we can see the genesis of the road-header, the longwall, and the continuous miner, all drag bit cutters. They have emerged as the solutions of choice for underground mining of softer materials such as coal and potash. In hard rock, the challenges are the forces required to break the rock, and the wear of the tools caused by the rock’s abrasiveness. Only disc cutters currently handle the challenges, and even then, often not economically. New materials like thermally stable diamond composite will help, as will combinations of mechanical cutters and other methods such as high-pressure water or high temperatures.It is not clear what will emerge as the consensus technique for hardrock cutting. Experience teaches that development is expensive and the market is small. Will mining companies partner with equipment developers to make the technological leap? Or will the solution come from a systems approach, not considered here?IntroductionBlasting is the dominant method of breaking rock for the purposes of mining. When used underground, blasting is part of a batch process. If rock can be cut rather than blasted, mining can become continuous, leading to process and efficiency improvements.Coal produced from underground mines is now predominantly excavated using mechanical means, but underground hard rock is still broken primarily by explosives.This paper traces the history of rock cutting, reviews the main physical processes that are or could be used, and comments on the future. It is written from the perspective of narrow-stope hard-rock mining typical of South African gold and platinum mines."

Jan 1, 2016

By O. Barron, C. Felix

In 2023, polymer electrolyte membrane fuel cell membrane electrode assemblies accounted for about 62% of the global fuel cell market share and this demand is expected to grow. Commercialisation requires technologies capable of cost-effective, high-volume manufacturing. The membrane electrode assembly is crucial and represents a significant cost to polymer electrolyte membrane fuel cell manufacturing. Manufacturing the electrode components for membrane electrode assemblies at high volumes can reduce production costs while delivering on the forecasted industry demands. Roll-to-roll is a mature coating technology applied in various manufacturing industries such as batteries, printed electronics, microelectronics, photovoltaics, printing, paper consumables, etc., with significant potential for polymer electrolyte membrane fuel cell manufacturing. While the high-volume production process for membrane electrode assembly manufacturing differs from laboratory-scale, the membrane electrode assembly structure remains unchanged. Roll-to-roll is a continuous coating process with speeds of 10 m/min being achieved. In this work, MicrogravureTM and slot-die coating methods have been adopted and have shown promising outcomes for producing gas diffusion electrodes for membrane electrode assemblies. An overview of the MicrogravureTM and slotdie coating methodologies is provided, and a discussion on preliminary results and challenges are presented. Work on MicrogravureTM gas diffusion electrode manufacturing has already achieved comparable performance with spray-coated gas diffusion electrodes. The influence of coating parameters and drying on the coated catalyst layer quality is discussed.

May 27, 2025

By M. Dworzanowski

The difference in the magnetic properties of minerals is the basis for magnetic separation. All minerals can be generally classified as ferromagnetic (strongly magnetic), paramagnetic (weakly magnetic) or diamagnetic (non-magnetic). Magnetic separation can be conducted dry or wet. The majority of the applications of wet magnetic separation in the mining industry are based on the wet drum magnetic separator. The wet drum magnetic separator has been in use for over 50 years and its design is based on a rotating drum installed inside a tank. Inside the drum are stationary, permanent magnets arranged in an arc to provide the magnetic field. These magnets can be of the ceramic ferrite type providing a low intensity magnetic field or of the rare earth type providing a high intensity magnetic field.

Jan 1, 2010