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By I. Hague

Support liners for underground applications include steel and timber sets, meshing and lacing, screen/mesh, shotcrete and thin support liners (superskins). Over the past few years, major advances have been made in the design and application of liners; especially shotcrete and thin support liners. For shotcrete in mines these advances include the common use of slick-lines to solve logistics problems, the design of alkali free accelerators, the use of synthetic fibres and the new generation application equipment. The field of thin support liners is a new one but advances have been dramatic. This paper discusses the progress made and the need for standardization in definitions and testing for thin support liners. It concludes that the newer technologies have a huge potential positive impact on the industries, from both safety and cost points of view. Le chemisage de soutènement pour extraction souterraine comprend des cadres d’acier ou de boisage, mailles et chapeau, cribles/mailles, béton projeté et des chemisages minces de soutènement (super-peaux). Dans les dernières années, des progrès considérables ont été fait dans la conception et application des chemisages, en particulier les chemisages de soutènement en béton projeté et les chemisages minces. Pour le béton projeté dans les mines, ces progrès comprennent l’utilisation courante de lignes de minerais broyés fin pour résoudre des problèmes de logistique, la création d’accélérateurs sans alcali, l’usage de fibres synthétiques et d’une nouvelle génération d’outillage. Le domaine des chemisages minces de soutènement est très récent mais les progrès ont été rapides. Cette étude présente les progrès accomplis et discute du besoin de standardisation dans les définitions et les tests pour chemisages minces de soutènement. La conclusion est que les technologies nouvelles présentent un énorme impact potentiel positif sur les industries, du point de vue à la fois de la sécurité et de la rentabilité. Unterstützungsverkleidungen für Untertaganwendungen inkludieren Flecht und Seilwerk, Gitter/Geflecht, Spritzbeton und dünne Unterstützungsverkleidungen (superskins). Während der letzten Jahre wurden grosse Fortschritte im Design und in der Anwendung der Verkleidungen gemacht; besonders bei Spritzbeton und dünnen Unterstützungsverkleidungen. In Bezug auf Spritzbeton in den Gruben schließen diese Fortschritte den allgemeinen Gebrauch von Rutschbahnen ein um Logistikprobleme zu lösen, das Design von alkalifreien Akzeleratoren, den Gebrauch von synthetischen Fasern und die neue Generation von Anwendungsausrüstung. Der Bereich der dünnen Unterstützungsverkleidungen ist neu, aber die Fortschritte sind drastisch gewesen. Diese Arbeit behandelt den erzielten Fortschritt, die Notwendigkeit der Normierung in den Definitionen und in der Prüfung dünner Unterstützungsverkleidungen. Sie kommt zum Schluß, daß die neueren Technologien, sowohl vom Gesichtspunkt der Sicherheit als auch der Kosten, eine sehr große potentielle positive Auswirkung auf die Industrien haben.

Jan 1, 2003

By S. Sarac

In this study, graphical and mathematical methods used to determine operating points in single or multiple fan ventilation systems are summarized. The problem is mathematically formulized for parallel connected fans in which analytical solutions are not possible. For n number of parallel connected fans, a non-linear equation system that consists of n number of non-linear equation sis derived. The Newton-Raphson method, which is a numerical analysis method, is adapted to solve this non-linear equation system and the solution steps are given as an algorithm. A computer program based on this algorithm is written and its applicability is proved.

Jan 1, 2000

By S. J. Oosthuizen

This paper examines innovation in relation to the availability of anew material: the metal titanium. The paper aims to highlight the need for the inclusion of entrepreneurial innovation as a necessary focus area in the development of a titanium metal value chain. Both the Department of Science and Technology (DST) and the Department of Mineral Resources (DMR) have identified the creation of titanium metals production capabilities as a key growth area for South Africa. Using historical literature as a source of data, the activities of selected innovators who used titanium metal as a central component in their success, were investigated. The origin of the process innovation behind the titanium metals industry, and two titanium product innovations: namely, medical implants and sporting goods, were detailed as case studies. It was found that individual innovators were responsible for the creation, and rapid growth, of the titanium industry and titanium product applications. There is a need to link the current research and development into titanium metals production with individuals and organizations capable of commercializing innovative processes and products.

Jan 1, 2011

By G. Kelly

A new minerals engineering education programme is being developed in Australia which aims to provide tertiary institutions with a package of educationally sound, high quality courses for undergraduates, postgraduates and professionals. The programme is jointly funded by the Minerals Council of Australia (MCA) and the Department of Education Training and Youth Affairs (DETYA) and brings together academics from a number of leading Australian universities, each developing modules in their particular area of expertise. The University of Queensland (UQ) and the Julius Kruttschnitt Minerals Research Centre(JKMRC) are jointly responsible for modules in several areas including comminution, physical separation and circuit design and optimization. Other modules are being developed by the University of South Australia (with the Sir Ian Wark Centre), Curtin University and Murdoch University. The major challenge of the programme is to provide a high standard of education that is accessible to students who may be located at several different institutions and some of whom maybe a long distance from the primary course leader. Rather than taking existing course material and putting it ‘on the web’, the programme aims to improve on past teaching practice through creative pedagogy and the development of interactive multimedia learning resources. Communications technology is used in an unobtrusive way, and the World Wide Web is used to create a flexible, user-friendly learning environment rather than to facilitate delivery of content. This paper describes the instructional design template currently being used and results of early implementation trials with groups of local and remote students.

Jan 1, 2003

By V. Coetzee

Keywords: Pyrometallurgy, furnace, PGM, platinum, nickel, copper, electric smelting, six-in-line, Peirce-Smith, Impala Platinum In 1992, a paper was compiled highlighting a common-sense approach to electric smelting at Impala Platinum. Since then, the smelter complex has undergone considerable changes. Mineral economics, UG2 exploitation, and changing environmental legislation have enforced numerous process upgrades, yet a common-sense approach has always been adopted. This document details the major changes in the smelter complex at Mineral Processes (Minpro) over the past 15 years, and provides the rationale for the changes.

Jan 1, 2006

By Luthie Els, Chris Coetzee, Roedolf Koekemoer, Casper Els, Olof Vorster, Frank Fereday

Three electric arc furnaces (EAFs) were constructed by Union Carbide at Tubatse Ferrochrome (TFC) in1975. This plant was expanded to four furnaces at the East Plant in 1985 and the gas cleaning system was enlarged without taking flow dynamics into consideration. In order to improve competitiveness, TFC has increased furnace capacity, partially substituted coal for coke, and changed the charge mix. These changes increase the heat and dust load into the air pollution control (APC) system. TFC embarked on a project to improve the APC capacity by: ?Quantifying the required off-gas capacity ?Optimising the aerodynamic flow through the system by means of Computational Fluid Dynamics (CFD) ?Converting the old Brandt Koyo top entry baghouses to bottom entry ?Upgrading the cleaning system ?Installing Gore-tex® ePTFE membrane filter bags The estimation of required off-gas capacity is traditionally done by rule-of-thumb methods such as specific extraction. A more elegant evaluation method was developed for simulating the effects of changes in charge mix on the furnace reaction gas volume and the APC system. Reaction gases are calculated by modelling the reactions taking place in the furnace and off-gas volumes are compared to both fan and baghouse capacity. This enables identification of bottle-necks in the off-gas system. CFD techniques were utilized to evaluate geometric imbalances and propose solutions to ensure optimal use of off-gas capacity. The system modifications were completed over several months and the modified equipment went into service in May2006.

Jan 1, 2007

By S. Khan, M. Auret

Due to the modernisation of mines, traditional training methods may be supplemented to support the upskilling of supervisors in mines. A project was initiated by the SAMERDI SATCAP programme to demonstrate the “art of possibility” through a modern training methodology. Two exemplar digital supervisory leadership development modules for underground gold and platinum-group metal conventional and modernising mines, were developed for potential uptake by the mining industry. These exemplar modules were exhibited on a digital platform, towards leading and driving mining modernisation. The research adopted a mixed method approach that included a literature review, a review of an existing supervisory leadership development programme, data gathering, a pilot study, and stakeholder validation workshops. The research supported the development of exemplar digitised modules. The two digitised modules were showcased to the industry for potential adoption. Training slides, a facilitator guide, and a training video were developed for ease of use by industry. The training modules are generic and not specific to a particular mine. They may be used by multi-commodity mines, including gold and platinum-group metals, as ‘stand-alone’ modules. They are customisable, through consultation with relevant service providers for specific working environments. The findings indicated that both the traditional classroom training and the new digitised online learning solution offer advantages for supervisory leadership development. Digital learning is not a new concept for supervisors at mines and modern training methods are well-supported by supervisors in the industry. A ‘modernised’ training solution may consider a ‘blended’ learning approach that combines traditional training with digital methods.

Jun 27, 2025

By S. Mohanta, I. D. Behera, B. Sahoo

"Run-of-mine coal contains particles of different sizes with different specific gravities, and when this coal is crushed, the amount of material present in a particular density class changes. This alters the washability characteristics of the coal, which affects the quantity, quality, and separation efficiency of the gravity-based coal washing process. The degree of difficulty in washing a typical coal at a particular specific gravity depends mostly on the amount of material occurring within ±0.1 specific gravity range, which is known as ‘near-gravity material’ at that particular specific gravity of separation. In this paper, two numerical indices, namely ‘near-gravity material index’ and ‘index of washability’, are used to quantify the distribution of near-gravity material in different density classes and to evaluate the degree of difficulty involved in the washing process. The results of this preliminary investigation indicate the uniform distribution of near-gravity material in all density classes for finer size fractions, whereas for coarser size fractions more near-gravity material is present in the lower density classes, making the washing process more difficult at a lower specific gravity of separation. IntroductionThe prime objective of coal beneficiation is to remove physical impurities as effectively and economically as possible. The beneficiation process includes various operations on the asmined coal to make it more suitable for enduse application without destroying the physical identity of the coal. There are several coal beneficiation processes, but gravity-based separators remain the most efficient unit operation for removing the undesirable gangue material from run-of-mine coal. These separators exploit the difference in density between coal particles and gangue particles to effect a separation. The feed is introduced into an aqueous suspension of ultrafine magnetite with a particular density. The feed particles with a relative density less than that of the suspension (clean coal) float to the top surface of the suspension, whereas particles denser than the suspension density (gangue material) sink to the bottom. When the difference in density between the particle and the aqueous suspension is large, the separation is easy, but when this difference is less the separation becomes much more difficult since the settling velocity of the particles is very low. This lower settling velocity increases the probability that particles that should report to floats report to sinks, and vice versa, hence increasing the amount of misplaced material. Therefore, the degree of difficulty in beneficiating a typical coal at a particular specific gravity depends on the amount of material occurring within ±0.1 specific gravity range. This is known as ‘neargravity’ material, also termed ‘near-dense’ material, at that particular specific gravity of separation."

Jan 1, 2016

By V. Jovicic, J. Likar

The knowledge of the geological sequence and hydrological conditions in the area of portals was the basis for the design of the entry of the highway into tunnel Trojane. Mudstone, claystone and sandstone dominate the rock layering, which is tectonically reworked and contains structural anomalies. The complexity of the sequence makes it impossible to survey all the relevant features along the full 3km length of the tunnel. Sudden and frequent transitions between litological sequences impose potential instabilities and make the excavation of the tunnel particularly difficult. The initial survey established the zones of potential failures. These were monitored using topographic survey and inclinometers with an aim to make further geotechnical analyses more reliable and adjusted to the ground conditions. The analyses of the wall construction and the results of the monitoring showed that the design of the retaining wall was adequate. La connaissance de la séquence géologique et des conditions hydrologiques dans l'aire des portails a été la base pour la planification de l'entrée de l'autoroute dans le tunnel Trojane. Le schiste, l'argilite et le grès dominent la couche rocheuse qui est tectoniquement transformée et contient les anomalies structurales. A cause de la complexité de la séquence, il est impossible de revoir toutes les particularités le long des 3 kilomètres de la toute longueur du tunnel. Les transitions soudaines et fréquentes entre les séquences lithologiques imposent l'instabilité potentielle et font l'excavation du tunnel particulièrement difficile. La revue initiale a été établie sur les zones où il existe l'éboulement potential. Elles étaient contrôlées à l'aide de la revue topographique et de l'inclinomètre pour que les analyses géotechniques suivantes soient plus sûres et adaptées aux conditions du sol. Les analyses de la construction des murs et des résultats du contrôle ont montré que la planification du mur réteneur était correspondante. Der Autobahneingang in den Trojane Tunnel war projektiert auf Basis von der Kenntnis der geologischen und hydrogeologischen Bedingungen in dem Portalgebiet. Das Gebiet besteht aus dem Tonstein und dem Sandstein. Die Schichten sind tektonisch verformt und sind deswegen sehr heterogen. Die anfaenglichen Untersuchungen haben die Zonen von den potentiellen Bruechen definiert. Weitere geotechnische Analysen waren fitted an reale geologische Bedingungen durch das Monitoring der potentiellen Bruchzonen, welches aus den topographyschen Messungen und Inklinometerdaten entstand. Die Analyse des Wandbaues und die Resultate von dem Monitoring haben erwiesen, dass die Wandprojektierung entsprechend war.

Jan 1, 2003

By J. Stacey

This study was undertaken to generate a locally relevant guideline for the socio-economic aspects of mine closure for South African closure practitioners and decision makers. It should also represent a resource for interested and involved stakeholders. Mine closure, and its related post-closure social, environmental and economic characteristics, is part of the lifecycle of mining operations, given the finite nature of the ore resource. Many coal mines are anticipated to close in the next ten to fifteen years in Mpumalanga, as the epicentre of the industry shifts towards the Waterberg. Social aspects of mine closure have been historically underplayed, and under researched. Coaltech thus commissioned two studies, the first of which examined the closure dynamics of 36 mines in Mpumalanga and KwaZulu-Natal in 2006. A follow-up study (July 2007) focusing on Mpumalanga3,4 confirmed some of the results of the first study. It also contained broad guidelines for mine closure covering social and labour planning, job creation, the use of mine infrastructure, developmental incentives, and environmental rehabilitation.

Jan 1, 2010

By A. Nieto

A vehicle proximity warning–collision avoidance system is being developed using GPS and wireless local area networks to improve safety of off-highway trucks in open pit mines. After two-and a-half years of research, software development, and laboratory testing, field tests were carried out at operating limestone quarries and open pit mining operations to evaluate GPS accuracy and overall system effectiveness under rugged operating conditions. This article describes the progress made on this NIOSH-funded project and discusses the GPS accuracy tests and overall system tests that were carried out during the year 2001 at the Colorado School of Mines Survey Field and at the Morenci open pit copper mine in Arizona. Keywords: GPS, Advanced Mining, Virtual Reality, Wireless Networks, Proximity Warning

Jan 1, 2003

By W. Mackenzie

The development of a resource project inevitably requires the investigation of a vast range of issues across most engineering disciplines - mining, metallurgical, chemical, civil, electrical, mechanical and environmental - as well as the geosciences. It is also a characteristic feature of the resource industry that no two orebodies - and hence no two development projects - are the same. So these technical issues have to be addressed to a greater or lesser extent in evaluating any resource project's development potential. Not surprisingly then, technical issues tend to predominate when assessing the development potential of a project in the process typically referred to as `doing a feasibility study'. But the principal purpose of a `feasibility study' is to determine whether a development opportunity makes good business sense, not just whether it is technically possible. Resolution of technical issues is often seen as the primary focus of a feasibility study, whereas in reality, these technical issues are the basis upon which an asset delivery and business plan is built. This is not to say that technical issues are unimportant - they are a prerequisite to the demonstration of a project's viability. The feasibility study process must therefore demonstrate that not only have the technical issues been satisfactorily addressed, but also that the broader commercial, economic and social issues have been considered in the development of a comprehensive business plan, which includes an assessment of the risk-reward profile of the proposed development. This paper will present a framework for the conduct of `feasibility studies' and provide guidance to minimum standards and best practice.

Jan 1, 2007

By N. Fardin, O. Stephansson, L. Jing

A pair of silicon rubber replicas of size 250 mm by 250 mm, from a natural rock joint, was used to produce several high strength concrete fracture replicas of different sizes, from 50 mm by 50 mm to 200 mm by 200 mm. The morphology of the concrete fracture replicas were digitized at the laboratory using a 3D-laser-scanning machine with high accuracy and resolution. The scale dependency of the geometrical properties, including surface roughness and aperture, of the samples were investigated using fractal method. The investigation was extended to study the scale effect on the mechanical properties of the concrete fracture replicas. Four concrete replicas having same geometry from each sampling size were sheared under four different normal loads. The results show that normal and shear stiffness and peak shear strength decrease with increasing sample size and decreasing normal stress. It is concluded that for accurate determination of geometrical and mechanical properties of rock joints in the laboratory and field scales, samples with size equal to or larger than stationarity limit are required. Silikongummiabdrücke der Größe 250 mm x 250 mm einer natürlichen Kluft dienten als Vorlage für mehrere Hochfestbeton Rissreplikas verschiedener Größe. Die Morphologie der Beton Rissreplikas wurde mittels eines 3D-Laserscanners hoher Genauigkeit und Auflösung im Labor digitalisiert. Die Skalenabhängigkeit der geometrischen Eigenschaften, dies inklusive Oberflächenrauhigkeit und Öffnungsweite, wurden mittels Fraktalen bestimmt. Die Studie wurde durch die Untersuchung der mechanischen Eigenschaften der Betonrepliken erweitert. Hierbei wurden vier Betonrepliken der selben Geometrie jeder Probengrösse unter vier verschiedenen normalen Belastungen abgeschert. Die Ergebnisse zeigen das sowohl Normal- und Schersteifigkeit als auch die Spitzenscherfestigkeit mit zunehmender Probengrösse und abnehmender Normalspannung abnehmen. Es hat sich gezeigt, daß für eine genaue Bestimmung der geometrischen und mechanischen Eigenschaften von Felsklüften im Labor und im Feld Proben einer Größe gleich oder größer des stationären Limits verlangt werden. Deux répliques en gomme de silicone d’une fracture naturelle, de dimension 250 mm par 250 mm, ont été utilisées pour produire des répliques en béton de haute résistance de dimensions allant de 50 mm par 50 mm à 200 mm par 200 mm. La morphologie de ces répliques a été digitalisée au laboratoire à l’aide d’un laser-scanner 3D haute résolution et haute précision. L’influence de l’échelle des propriétés géométriques, incluant rugosité et ouverture, a été étudiée en utilisant la méthode des fractales. Des essais complémentaires ont été réalisés afin d’étudier l’effet d’échelle sur les propriétés mécaniques des répliques de fracture en béton. Quatre répliques béton de même géométrie pour les différentes tailles d’échantillons ont été cisaillées sous quatre valeurs de contrainte normale. Les résultats montrent que la rigidité normale et tangentielle ainsi que la résistance de pic diminuent en proportion de l’augmentation de la taille de l’échantillon et de la diminution des contraintes normales. On peut en conclure que, pour une détermination précise des propriétés géométriques et mécaniques des fractures au laboratoire et sur le terrain, des échantillons de taille égale ou supérieure à la limite stationnaire sont nécessaires.

Jan 1, 2003

By C. Haberfield, J. Szymakowski

Recent studies by the authors into the behaviour of jointed rock masses using direct shear testing have confirmed that joint spacing has a significant effect on rock mass strength. The rock mass failure envelopes assessed from these tests have been compared to failure envelopes obtained using the Hoek-Brown GSI criterion. Good agreement between measured and estimated GSI strength envelopes where obtained when joint spacing was considered in the assessment of GSI. Les études récentes conduites par les auteurs sur le comportement des joints rocheux employant l'essai direct de cisaillement ont confirmé que l'espacement a un effet significatif sur la force de la masse rocheuse. Les enveloppes de ruptures obtenues pour ces essais ont été comparées à l'enveloppe de rupture obtenue en utilisant le critère GSI Hoek-Brown. Une bonne corrélation a été constatée entre les enveloppes obtenues expérimentalement et les enveloppes calculées par la méthode GSI quand l'espacement des joints a été pris en considération dans l'évaluation de GSI. Kuerzliche Untersuchungen der Autoren betreffs Reaktionen von gebrochenen Felsmassen zu direkter Scherkraft, bestaetigen, dass die Abstaende von Rissen einen deutlichen Einfluss auf den Widerstand der Felsmassen hat. Die Bruchbereiche der Felsmassen die von diesen Untersuchungen entwickelt wurden, wurden verglichen mit den Bruchbereichen, die man mit der Anwendund der Hoek-Brown GSI Formulierung erhaelt. Eine gute Uebereinstimmung zwischen gemessenen und errechneten GSI Festigkeitsbereichen wurde erzielt, wenn der Abstand der Risse in der Berechnung der GSI in Betracht gezogen wurde.

Jan 1, 2003

By P. E. Hand

Coal is a complex heterogeneous commodity that can be mined in a number of ways and needs to be processed to a homogeneous quality that satisfies the customer?s requirements, while attempting to maximize revenues. Only a small proportion of coal is suitable for metallurgical use. Export coals cover a wide range of qualities and some coals can be used optimally in the raw state for energy production. Critical quality parameters vary and can be a combination of heat value, ash, volatiles, sulphur, phosphorus, sizing, amongst others. The level of beneficiation is generally dictated by the washability of the coal, mining contamination, and the target product quality. The steps in the coal chain covered in this paper comprise exploration, mining selections, production, the washing process, and product delivery. Many points of sampling are needed to maximize yield at the correct quality, and some of these will be described in the paper. Keywords coal chain, coal beneficiation, sampling.

Jan 1, 2014

By J. Sepulveda

"Despite the recognized influence of product fineness on line capacity and downstream process performance, few mineral concentrators today use particle size measurement of the final product in automatic control applications for particle size. ‘Near-line’ particle size instrumentation has existed for decades and is utilized in modern concentrators, but low availability and measurement frequency, due to problems with slurry sampling and transport systems, make these technologies unreliable for use in automatic control. An innovative technology for real-time particle size measurement on individual hydrocyclones, named CYCLONEtrac™ PST (particle size tracking), has been developed by CiDRA Minerals Processing, and proven in commercial installations, demonstrating near 100% availability with minimal maintenance requirements, thus overcoming the limitations of previous technologies. Potential stakeholders require convincing, reliable information regarding the economic value delivered by automatic grind control projects. In this paper we present a methodology for estimating such value with the CYCLONEtrac™ PST technology, and demonstrate unique opportunities to improve process stability and performance. Based on actual plant data accumulated over time, the evaluation approach assesses and highlights the significant potential process improvement that can be expected with the particle size tracking technology. As an extension of previous work, in this paper we present the key operating criteria for optimizing the production of valuable metals and increase mill throughput by identifying the optimal grind size. As this requires operating closer to the process boundaries, accurate real-time particle size measurements, such as those provided by the CYCLONEtrac™ PST system, become essential for achieving the maximum potential value from every operation. For further illustration, data from three different copper plants is compared.Introduction Owners and operators of mineral concentrators constantly search for the most economically attractive way to increase the output of valuable metal. A logical approach is to identify a key parameter that has the greatest impact on the performance of multiple stages of the process and then use a holistic analysis methodology to determine how this key parameter can be controlled to optimize the final output.Particle size is widely recognized as such a key parameter; however, very few concentrators today use real-time particle size measurements for automatic control of the final product size due, to a large extent, to the inherent limitations of existing technologies. ‘Near-line’ particle size measurement instrumentation, which has been used for decades, typically suffers from low availability because the fundamental measurement technologies were developed for other, less demanding industries and then adapted to the harsh environment of the typical mineral concentration process. An outline of the key differences among the available technologies used for particle size measurement in comminution circuits has been completed in previous work, and plant data has proven the benefits of measurements on individual cyclones – something that, until now, has not been possible (Cirulis, 2017)."

Nov 1, 2018

By A. S. Macfarlane

This paper describes how knowledge of the orebody morphology and ore morphology can be used to optimize the planning, mining, and metallurgical output from an open pit copper mining operation, such as to significantly increase the stability of the whole value chain process, and increase the reliability and value of the process outputs. In the case under consideration, the orebody contains both copper and cobalt. This in itself provides a challenge, in that the two metals do not occur in consistent ratios across the orebody as a whole. Furthermore, mineralogical differences within the orebody have a significant impact on plant performance in terms of throughput rates, acid consumption, and recoveries. In order to stabilize and optimize the plant performance, it is necessary to firstly have a complete understanding of the geometallurgical factors that affect performance, and then to have a sound knowledge of how these are distributed within the orebody. These models then inform the mine planning strategy that optimizes cash flow and NPV, and also allow the development of a stockpiling strategy that not only stabilizes the plant, but also allows variations in the plant feed according to ore type and grade in volatile price scenarios. Integral to the realization of these opportunities is the establishment of an appropriate measuring, control, and reconciliation system, customized to the optimization objectives. The paper describes how all of these factors and strategies can be integrated to produce optimal value from the orebody through to final dispatched product. It also shows the significant value that can be released through such an approach.

Jan 1, 2014

By H. Lagendijk, I. J. Reinecke

Mintek was contracted by Oriel Resources plc in 2004 to conduct a preliminary assessment study on smelting ferronickel from the large but relatively low grade Shevchenko nickel ore deposit in Kazakhstan. A detailed feasibility study (?DFS?) was awarded to Bateman BV following promising results from the preliminary assessment study (?PAS?) and small-scale pilot plant test work. As part of the DFS, a total of 450metric tons of ore was collected from three different locations in the deposit and shipped to Mintek. After sampling, the bulk sample was prepared for smelting. This comprised crushing, screening and calcining with each step done separately for the three different lots. The chemical composition of the ore from the deposit is relatively high in silica and therefore falls out of the MgO to SiO2 range that is normally processed by pyrometallurgical means to produce ferronickel. The main objective of the testwork was to demonstrate that a method could be found and successfully applied to smelt these siliceous ores and produce an acceptable nickel-containing alloy. A 2-m ID DC arc furnace was installed with a twin-cathode (electrode) configuration to replicate the proposed commercial-scale furnace and also incorporated an advanced design of water-cooled copper panels in the lower furnace sidewalls to withstand the aggressive nature of the high SiO2-containing slags. The reductant used was a high-volatile coal from Karaganda in Kazakhstan. The reductant addition was adjusted to achieve a 90% recovery of nickel. In the assessment of the process metallurgy, some deviation from equilibrium conditions was observed. This deviation is ascribed to the intermittent existence of a smelting bath partially covered with feed during the testwork. Optimization of smelting conditions should result in the metallurgy (slag metal equilibrium) being closer to the theoretical predictions and make the production of a 20% nickel alloy possible at 90% nickel recovery. The solution for the successful processing of these siliceous ores was found in the attainment of the necessary operational stability through the control of arc length, operating temperature, open-bath smelting conditions and flux additions of up to 10% dolime for the most siliceous of the three ore types. The test work carried out by Mintek provided the basis for the process flow sheet and engineering design of the DC arc smelting furnaces for the Shevchenko Nickel project.

Jan 1, 2007

By S. Sakurai

We discuss the mechanical characteristics of underground structures that are subjected to vertical oscillations. Under such circumstances - expected when an earthquake rupture occurs very close to highly developed urban areas - the conventional seismic analysis, which mainly considers horizontal shear oscillations, may not be fully valid. Our analysis, based on the elastic wave theory, shows the effects of vertical disturbances and the generation mechanism of the unique damage patterns observed on the occasion of the 1995 Hyogo-ken Nanbu (Kobe) Earthquake. Wir diskutieren über die mechanischen Eigenschaften der unterirdischen Strukturen, die sich vertikalen Schwingungen aussetzen. Unter solchen Umständen - erwartet, wann ein Erdbebenabbruch sehr nah an hochentwickelten städtischen Bereichen geschieht - kann die herkömmliche seismische Analyse, die sich hauptsächlich horizontale Schubbewegungen überlegt, möglicherweise nicht völlig gültig sein. Unsere Analyse, basiert auf der elastischen Wellentheorie, zeigt die Effekte der vertikalen Bewegungen und den Erzeugungsmechanismus der einzigartigen Beschädigungsmuster, die anläßlich des 1995 Kobe Erdbebens beobachtet wurden. Nous discutons les caractéristiques mécaniques des structures souterraines qui s’exposent aux oscillations verticales. Dans ces conditions - s’attendent quand une rupture de tremblement de terre se produit tout près des secteurs urbains fortement développés - l’analyse séismique conventionnelle, qui considère principalement des oscillations horizontales de cisaillement, peut ne pas être entièrement efficace. Notre analyse, qui est basée sur la théorie des vagues élastiques, montre les effets des mouvements verticaux et le mécanisme de génération des modèles uniques de dommages, que nous avons observés à l’occasion du tremblement de terre 1995 de Kobe.

Jan 1, 2003

By A. Basçetin

Equipment selection in mining engineering is one of the most important decisions that affects the mine design, production planning and economic parameters in open pit and underground mining. Mine planning engineers generally use their intuition and experiences in decision making. Mostly, linguistic variables (the weather is raining, soil is wet, etc.) come into question and decision-makers may not know how these variables are computed. Since the advent of the fuzzy set theory, these uncertainties are easily interpreted in the decision-making process. The development of computer technology and programming of colloquial language with expert systems have considerably reduced decision-makers? burden. This paper reviews the development of a computer programme software called EQS (EQuipment Selection) that automates equipment selection in mining engineering using fuzzy set theory. The EQS with an introduction of the concepts and theories of multiple attribute decision-making, the fuzzy set theory, and EQS applications to mining industry problems with case studies are presented

Jan 1, 2006