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By J. Martinovic

The large proportion of gangue minerals present in platinum bearing ores in South Africa provides challenges to the flotation and downstream processes. In order to take effective measures to reduce their recovery in flotation, an understanding of the mechanisms and factors influencing their behaviour is needed. Typical gangue minerals are pyroxene, feldspar, quartz, chromite and talc. Of these, talc is a naturally hydrophobic mineral and although it is present in relatively small quantities, it has a disproportionate effect as it has a strong froth stabilizing effect, increasing the recovery of other gangue minerals by entrainment. Talc recovery is effectively reduced with the addition of polymeric depressants. Although the other gangue minerals are assumed to be hydrophilic and their recovery by entrainment is expected to follow the water recovery, there is some evidence that they may be activated by the typical reagent suites used. Reagents such as copper sulphate, added as an activator, and collectors are used to selectively induce hydrophobicity on the sulphides. It has been shown that some of these gangue minerals can be activated. This research work investigates whether inadvertent copper activation is mineral specific and evaluates the mechanisms and factors affecting the reversal of activation with the addition of the depressants using electrokinetic measurements, adsorption and microflotation tests. Results are presented that show that the selected minerals do respond differently and that the reversal of activation is dependent on mineral type, depressant type, dosage and ionic strength of the electrolyte.

Jan 1, 2005

By Xu H.

In recent years, the mineral applications dealing with more complex data in distributed environment have grown rapidly. Many mineral and mining organizations have to organize internally and globally distributed manufacturing and experiment sites, which share the roles of databases and other multi-services like software programs. Thus, there are commercial and technical pressures pushing the mineral software vendors to move their current service toward Web service. XML has gained wide acceptance for representing, storing and transferring structured data and documents of many kinds, especially in scientific communities. However, so far there is no such a Markup Language in mineral industry. A XML-based uniform encoding, which is called MineML(Mineral Markup Language), is proposed and developed in this project. The framework of the MineML specification is created. MineML will play the role as shared protocols within mineral domain for archiving, transferring the multi-nature data between the software packages on the desktop over the Internet and sharing the services between users at different sites. Inspired by MLA’s (Mineral Liberation Analyser, JKMRC, University of Queensland, Australia) Mineralogical Data Presentation Program, a proof-of-concept prototype of Web Service is developed here to validate and demonstrate the MineML specification. Certain strategies, specific technologies and tools are adopted to create such an environment. To accomplish that, a set of experimental MineML documents including correlated XML, XSD (schemas) and XSL(stylesheets) documents have been elaborated for archiving, presenting and transferring the mineralogical data information, with the persistence on flexibility and extensibility for generic mineral and mining data handling.

Jan 1, 2003

By J. Kuijpers

Failure and fracturing are often regarded as synonymous. While this is obviously true in an environment dominated by tensile stresses, it is still not clear how failure and macro fracturing are related in a compressive stress environment. Excavations at great depths are typically subjected to compressive stresses only. The fracturing observed around such excavations is therefore commonly assumed to be induced by such compressive stresses. The physics of such a phenomenon have unfortunately never been explained properly, so that the formation of these so-called extension fractures still remains a mystery. As the presence of fractures is an important factor affecting the stability of underground excavations, it is of practical relevance to understand their formation. In this paper, a possible explanation is proposed. It is argued that fracturing in a compressive stress environment is a secondary effect. Primary failure, in the form of micro fracturing and associated damage is assumed to precede the major fracture processes. The fractures are thus generated in response to material failure and may not directly be the cause of failure. The implications for material response and behaviour are discussed. Keywords: micro fracturing, macro fracturing, extension fractures, failure, compressive stresses, damage, excavations.

Jan 1, 2000

By R. T. Jones

The 20 Mt reverberatory furnace slag dump at Nkana in Zambia contains a substantial quantity of cobalt. A 40 MW DC arc furnace has been built at Chambishi for the purpose of recovering cobalt from the slag. The technology was jointly developed by Mintek and Anglovaal Mining Ltd (Avmin), and the furnace was designed by Bateman Titaco. Testwork at the 150?250 kW scale was conducted at AVRL, and larger scale piloting was conducted at Mintek (in partnership with Avmin) in a 3 MW DC arc furnace. Approximately 840 tons of Nkana dump slag (ranging from 0.66% Co) was processed at power levels around 1-2 MW. Good overall cobalt extraction was achieved, and approximately 100 tons of cobalt-bearing alloy was produced (containing 5 to 14% Co). This testwork demonstrated that the Nkana dump slag could be processed in a DC arc furnace of suitable design, to produce a cobalt-bearing alloy suitable for further hydrometallurgical processing. Bateman Titaco were contracted to design and build the furnace, and the design team contained representatives from Avmin and Mintek. The project was conceived as a fast-track exercise, and many activities had to be run in parallel. Notable features of the furnace include an ABB power supply, a Concast conductive hearth, the refractory design, and copper cooling in the sidewalls. Power to the furnace was switched on during January 2001.

Jan 1, 2002

By L. K. Bandyopadhyay

The expert system component of Knowledge Base System supports the analysis and interpretation phases of ventilation design with an algorithmic program used for the solution of alternate design. The paper describes the ?ES-VENT? knowledge based system developed at Central Mining Research Institute, Dhanbad, India for an on-line diagnosing of the ventilation problems using the ?IITMRULE? expert system development tool. In the ?IITMRULE? expert system tool, it has been decided to use a backward chaining reasoning process to reach the goal state i.e. the final conclusion. ES-VENT system is made of three modules: On-line Data, Diagnostics and KBS. Each module is being a collection of several programs. The paper mainly deals with the parameters affecting the ventilation of underground mines such as air-velocity, air pressure, temperature, dust, and humidity and gas contents. The graphical presentation of these parameters on the computer and the interactive part of the developed program is expected to help a ventilation officer to determine the changes in a ventilation circuit necessary to bring the mine ventilation to the desired value. Once such changes are physically effected, the display will indicate if the changes have brought the desired effect or not on ventilation. Keywords: Ventilation network, on-line data, expert system, intelligent system, knowledge base, inference engine.

Jan 1, 2002

Council for 1996/97 President Dr N.A. Barcza President Elect R.P. Mohring Vice Presidents Senior J.R. Dixon Junior M.H. Rogers Immediate Past President D.A.J. Ross-Watt Honorary Treasurer J.A. Cruise

Jan 1, 1997

By S. M. Rupprecht

"SynopsisThis paper is intended to document recent personal thoughts, opinions, and debate around the South African Code for the Reporting of Exploration Results, Mineral Resources and Mineral Reserves (the SAMREC Code) (2009) and its current usage by Competent Persons. Admittedly, some debates are as old as the SAMREC Code itself and have been ‘parked’ as no consensus could be reached by members of the SAMREC Working Group.Some of the more critical issues currently under examination are the definition of Competent Person and the potential registration of Competent Persons, the current re-write of the Code, and the introduction of reporting of Exploration Results, Mineral Resources, and Mineral Reserves on an ‘If not – why not’ basis, noncompliance with the Code and discipline, the role of the Johannesburg Stock Exchange Readers Panel, and the valuation of mineral assets based on scoping studies.IntroductionThis paper is intended as a personal memoir of recent thoughts and debate around the South African Code for the Reporting of Exploration Results, Mineral Resources and Mineral Reserves (the SAMREC Code) (2009) (‘the Code’). Admittedly, some debates, such as reporting of Mineral Reserves inclusive or exclusive of the Mineral Resource, are as old as the SAMREC Code itself and have been ‘parked’ as no consensus could be reached by members of the South African Mineral Resource Committee (SAMREC) Working Group. The author, who has been involved with the SAMREC Working Group since 2007, offers observations in his personal capacity as a professional mining engineer with the intent of getting practitioners to contemplate the influence of the Code on the mineral industry. Current practices in the compilation and reporting of Exploration Results, Mineral Resources, and Mineral Reserves are often deficient in adhering to the Code and a conscious effort must be made by the mining sector to improve the standard of public reporting, in particular Competent Person Reports (CPRs) and Public Reports issued by listed mineral exploration and mining companies."

Jan 1, 2015

By Christian Roche

Our study is focused on the sub-assembly con-tact shoes, pressure rings and pressure bellows. We were keen to mainly study [ ] 1.The contact shoe design 2.The most efficient pressure to ensure an optimal electrical contact between the contact pad itself and the casing 3. The contact shoe cooling circuit in view to provide to the shoe the best mechanical and electrical characteristics in order to bring to the users of COFOR® components a new standard in process setting technical solutions. A finite elements simulation, combined with a thermal and structural studies were used. Our presentation which follows is dedicated exclusively on the influence of the contact shoe cooling system on the process through a thermal and structural analysis. [ ]

Jan 1, 2007

FOURTH INTERNATIONAL CONFERENCE ON VACUUM METALLURGY This Conference will take place in Tokyo from June 4th-8th 1973. The language used will be English. Inquiries should be addressed to: Mr S. Tabata, Conference Secretariat, The Iron and Steel Institute of Japan, (Nippon Tekko Kyokai), Keidanren Kaikan (3rd Floor), 9-4, Otemachi 1 - Chome, Chiyoda-ku, Tokyo, JAPAN. SYMPOSIUM ON BLAST FURNACE (A.I.M.M.) February 15-17, 1972 Circulars setting out the programme for the symposium, and registration forms, may be obtained from the Secretary of the S.A.I.M.M.

By R. Weideman, M. Le Roux, F. B. Waanders, Q. P. Campbell, E. Fosso-Kankeu, D. Moyakhe

"*Paper written on project work carried out in partial fulfilment of B.Eng (Chemical Engineering) degreeSynopsisSpent coffee grounds were transformed into biochar using a hydrothermal method. Some of the biochar product was pre-treated through surfactant impregnation with sodium dodecyl sulphate (SDS) to enhance its adsorption capacity. The non-treated(NT) and pre-treated(PT) biochars were characterized using FTIR spectroscopy and SEM-EDS analyses, which revealed that the products had the potential for adsorption of heavy metals from solution and confirmed the successful impregnation of biochar with SDS surfactant. The two adsorbents were then used for the removal of cadmium from solution and the adsorption behavior and capacity determined through adsorption isotherm, kinetic, and thermodynamic studies. It was found that the cadmium was adsorbed in several concentric layers on the surface of the adsorbents through a chemisorption mechanism. The PT biochar was identified as a superior adsorbent, with a capacity of qe = 10.67 mg/g compared to the NT biochar with qe = 4.82 mg/g. The adsorption of cadmium onto the PT biochar was further determined to be spontaneous and endothermic. It was therefore concluded that the PT biochar shows potential as an adsorbent and could be considered for implementation in the treatment of metal-polluted effluents. IntroductionCoal mining operations are notorious for producing large amounts of waste tailings, which are disposed of in the form of a slurry on tailings dams. This inadvertently contributes towards environmental problems (Jin, Mansour, and Thomas, 2017). Heavy metals are one of the most common pollutants that originate from solid mine waste disposal facilities, and these can leach into groundwater supplies, contaminating them and rendering the water unsuited for human consumption (Salomons, 1995). Cadmium occurs in conjunction with metalliferous ores and can cause severe damage to agricultural soils and drinking water supplies in the vicinity of mining sites (Dudka et al., 1995). It has a tendency to migrate into the surrounding vegetation, which in turn can cause harm to humans and animals when consumed (Marquez et al., 2018)."

Jul 1, 2019

?Longhole blast hole drilling? techniques are not new to the mining industry. Appropriate mechanization and improvement of the techniques and application has evolved from the industry requirements. Today safety and economics play a larger role in the excavation of ore passes, ventilation passes, and relatively small inclined excavations in the conventional gold and platinum industry. The application of dropraise drilling from the top or from the bottom is discussed investigating the current techniques available, DTH application, advantages and disadvantages, limiting factors, typical layouts and proposals, the drop raising technique and future applications. Similarly, the application of longhole blast hole drilling in tabular and massive orebodies is discussed with emphasis on the DTH application, advantages and disadvantages, limiting factors, typical layouts, the long hole stoping techniques and future applications.

Jan 1, 2003

By M. L. Smith, G. Karunatillake

Lead-zinc production at MIM, Mount Isa includes three mines, a lead concentrator, zinc filter plant and lead refinery. Lead production is vertically integrated with lead-silver bullion shipped from Australia to London for refining. Zinc is sold as a concentrate. All three mines have reached varying states of maturity mining a multitude of orebodies having significant variation in grades and metallurgical recovery for three metals. Based on current levels of measured resources, the remaining project life is at least ten years. The objective is to schedule production over the life of all three mines so as to maximize the present value of the complex. Additional scheduling complexity arises out of the implementation of long-term schedules, capital expansion projects for both mining and processing, the presence of substantial inferred reserves and interactions with MIM copper production. A large-scale, time-dynamic, life-of-complex Mixed Integer Program (MIP) production schedule was formulated to optimize lead/zinc cash flow based on a detailed life of project production scheduling study. The requirements for such a study are detailed herein. The operational feasibility of the MIP solution is compared against a non-optimal approach to strategic life-of-mine scheduling. The strategic planning emphasis placed on the MIP is compared to the implementation of a life-of-mine schedules at Mount Isa using spreadsheets and other popular commercial mine schedulers.

Jan 1, 2003

By I. Grigoriev, A. Yolkin, E. Freiberg, A. Fedchun, A. Kolichko

Abstract: The paper describes the engineering-geological conditions and the structural decisions of the underground machine hall of Rogun HPP under construction in Tadjikistan on Vaksh river as well as the results of physical model studies and long-term in-situ investigations of the variation of the stress-strain state of the surrounding rock mass and the supports of openings, and the assessment of the stability of openings during and after the construction. The analysis of the results of long-term in-situ observations and previous model studies permitted to make the assessment of the present-day state of the machine hall and give recommendations of its further use. Zusammenfassung: Im Vortrag werden die ingenieurgeologischen Bedingungen und konstruktiven Lösungen für die unterirdischen Maschinenhalle des in der Republik Tadshikistan am Fluss Wachsch im Bau stehenden Rogunskaja-Wasserkraftwerkes, die Ergebnisse von experimentellen Forschungen (in physikalischen Modellen) und Naturbeobachtungen der Spannungs-Verformungszustandsänderungen des umliegenden Felsmassivs und Ausbaues von Untertagebauten, sowie Ergebnisse der Bewertung der Standfestigkeit von Untertagebauten während des Bauvorganges und nach der Bauperiode beschrieben. Auf Grund der Analyse von Ergebnissen der dauernden Naturbeobachtungen und früher durchgeführten geomechanischen Modellversuche wird der heutige Zustand der Maschinenhalle des Wasserkraftwerkes bestimmt und werden die Empfehlungen für ihren weiteren Benutzung angeführt. Annotation: L’exposé décrit les conditions d’ingénieur et celles géologiques, et les solutions constructives de la salle des machines de la Centrale hydroélectrique (CHE) Rogounskaya sur le fleuve Vakhch, les résultats d’études expérimentales (sur des modèles physiques) et d’observations extérieures sur place concernant des changements de l’état de tension-déformation d’un massif environnant et du cuvelage des excavations, ainsi que les résultats d’évaluation de la stabilité de l’excavation au cours de la construction et à la période post-construction. A la base de l’analyse des résultats des observations de longue durée et des études préalables géomécaniques sur des modèles, l’évaluation de l’état actuel de la salle des machines de la CHE est effectueé, et les recommandations sur son utilisation ultérieure sont présentées.

Jan 1, 2003

By S. Kamalpour

It has been observed that the productivity of ferromanganese furnaces, and the stability of metal and slag compositions, vary considerably according to the type of coke used as reductant. However, the desired properties of coke for optimum furnace performance are not well understood. In this investigation, the behaviour of four cokes, which exhibited a wide range of performance in ferromanganese production, was investigated by means of laboratory simulations of reducing conditions in the furnace. The Stationary Charge in Controlled Environment (SCICE) technique was used to simulate the conditions in the furnace shaft. Batches of raw materials, mixed in the same proportions as used in practice, were heated at fixed rates to 900, 1100 and 1300°C then cooled. The mass loss was used as a measure of the degree of reduction. Conditions in the lower part of the furnace were simulated by means of melt-reduction experiments in which lumps of coke were drilled out to form crucibles in which enriched ferromanganese slags were reduced at 1500 and 1550°C then cooled. An examination of the raw materials and the cooled, reacted charges using a variety of analytical and characterization techniques enabled the sequence of reaction and changes in morphology of the raw materials to be followed. This enabled an understanding of the behaviour of the cokes during reduction to be developed, which was then used to explain the observed performance of the cokes in practice. By relating the observed behaviour of the cokes in the laboratory tests to measurable properties of the unreacted cokes and to their observed performance in practice, it was shown that to achieve high productivity and good furnace performance, cokes should be selected to have moderately high reactivity towards CO2 (Boudouard reactivity) relative to conventional iron blast furnace cokes.

Jan 1, 2004

By R. P. Jensen

This is a sampling of the papers presented at the conference, the proceedings can be bought from the SAIMM Arbitrary Lagrangian Eulerian (ALE) computational techniques allow treatment of gases, liquids and solids in the same simulation. ALE methods include the ability to treat shock waves in gases, liquids and solids and the interaction of shock waves with each other and with media from one of the other categories. ALE codes can also treat explosive detonation and the expansion of the explosive gases and their interaction with air and solids. ALEGRA is a 3-D ALE code that has been developed at Sandia National Laboratories over the past few years. ALEGRA has been applied to a 2-D simulation of presplitting using decoupled explosives in rock blasting with very interesting results. The detonation of the explosive at the bottom of the hole sends a shock wave up the borehole driven by the explosive gas expanding into air. The explosive gas compresses the air against the stemming column where it rebounds and recompresses at the bottom of the borehole. This type of ringing takes several cycles to damp out. The explosively induced expansion of the borehole is also treated by ALEGRA as well as the shock wave imparted to the rock. The presentation of this paper will include several computer animations to aid in understanding this complex phenomenon.

Jan 1, 2000

The 103rd Annual General Meeting of The South African Institute of Mining and Metallurgy was held in the Gold Room, Transvaal Automobile Club, 60 5th Street, Lower Houghton, Johannesburg on Wednesday, 16th August, 2000. Welcome The President extended a special welcome to the guests and representatives of our sister institutes and other associations. Also to recipients of awards, senior members of industry, Honorary Life Fellows, Past Presidents, our Members and other guests, among them the following: Reinie Meyer, President, The Geological Society of South Africa Dr Nielen van der Merwe, Chairman, The South African Institute of Rock Engineering Chris Fourie, President, Institute of Mine Surveyors of South Africa

Jan 1, 2000

By J. N. Van der Merwe, D. P. Roberts

The two components of pillar design formula being used in South Africa are pillar strength and pillar load. While considerable effort has been directed to the determination of pillar strength, the other half of the safety factor equation, the load, has not received the same amount of attention. The load acting on pillars has always been calculated using the Tributary Area Theory (TAT). This paper summarises the recent studies on coal pillar loading using various numerical models. It concludes that although there are meaningful differences under certain circumstances, there is still a compelling argument to use the TAT in coal pillar design. Les deux parties composantes de la formule de conception de pilier généralement utilisée en Afrique du Sud sont la résistance de pilier et la charge de pilier. Tandis que des efforts considérables on été dirigés vers la détermination de la résistance de pilier, l’autre moitié du facteur de sécurité n’a pas reçu la même attention. La charge agissant sur les piliers a toujours été calculée avec la Théorie d’Aire Tributaire (TAT). L’étude présente résume les études récentes sur la charge de pilier de charbon utilisant des modèles numériques variés. La conclusion est que bien qu’il y ait des différences significatives selon les circonstances, il y a toujours un argument puissant pour utiliser le TAT dans la conception de pilier de charbon. Die in Südafrika für die Auslegung von Pfeilern verwendeten zwei Formelkomponenten sind Pfeilerstärke und Pfeilerbelastung. Während beträchtlicher Aufwand zur Bestimmung der Pfeilerstärke gemacht wurde, wurde der anderen Hälfte der Sicherheitsfaktorsgleichung nicht die gleiche Aufmerksamkeit gewidmet. Die auf die Pfeiler wirkende Last wurde immer unter Verwendung der Tributary Area Theory (TAT) berechnet. Diese Arbeit fast neuere Studien betreffend der Belastung von Kohlepfeilern unter Verwendung verschiedener numerischer Modelle zusammen. Die Schlussfolderung ist, daß obwohl unter bestimmten Vorraussetzungen bedeutende Unterschiede existieren, nach wie vor ein bezwingendes Argument besteht TAT in der Kohlepfeilerauslegung zu verwenden.

Jan 1, 2003

By W. Breytenbach

Traditionally, dithiocarbonates (xanthates) have been the preferred collectors for the flotation of platinum-bearing sulphides. However, collector development has led to trithiocarbonates (TTC), which have proven to be very effective bulk sulphide collectors. The interest in TTC flotation behaviour is currently focused on the interaction of these collectors with other collectors, specifically the dithicarbonates. Batch-flotation research has shown synergism to exist among dithiocarbonate, dithiophosphate and trithiocarbonate collectors. Increased sulphide recoveries, both for the first-minute and final concentrate, were realized using mixtures of these collectors relative to the standard.

Jan 1, 2003

By D. Nag, J. Fernando

Hazelwood Power Mine is one of the largest open pit brown coal mines in Australia. The removal of overburden is the first step in coal winning operation. The primary aim of construction of overburden dump is to provide an effective stable working surface for stacker. The paper discusses site investigation techniques used to determine dump soil properties, stability analysis method using GALENA and GWEDGEM, results of stability analysis. The paper concludes with recommendation for a safe dumping strategy for level 2 stacker dumping.

Jan 1, 2003

By Yijun Caoa, Xiuxiang Taoc, Zhongbo Hub, Yinfei Liaoa

A new preparation scheme for a difficult-to-float coking coal from the Kailuan Mine, Tangshan, China was investigated. The results showed that grinding followed by column flotation was beneficial for obtaining products with low ash content. The positive effect of grinding on the coal floatability is attributed to the liberation of intergrowths and coal surface improvement. Tests indicated that 10 minutes was the optimum grinding time, and over grinding resulted in a deterioration in flotation performance. With a grinding time of 10 minutes, conventional flotation had potential to yield a product with around 12.42% ash content and 69.15% combustible recovery. Column flotation can reduce the product ash content to 11.15%and increase combustible recovery to 74.47%. Consistently better flotation results reveal that column flotation is more efficient than conventional flotation for such fines.

Jan 1, 2015