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By R. Shen

This paper presents results of a feasibility study of recycling manganese furnace dust generated in production of ferromanganese and silicomanganese at Tasmanian Electrometallurgical Company, Australia. Dried manganese furnace dust contains about 20 wt% of carbon, in average 33.4 wt% of manganese and 1.3 wt% of zinc. Manganese in the dust is in the form of MnO, Mn3O4 and MnCO3; zinc is mainly in the form of ZnO andZnSO4. Analysis of the zinc balance with dust recycling showed that to keep zinc intake at the acceptable level, it should be partly removed from the dust. In the reduction laboratory experiments, zinc oxide was reduced to zinc vapour by tar of the dust. Reduction of zinc oxide started at 800°C and zinc removal rate increased with increasing temperature; removal of zinc was close to completion at 1100oC. Optimal conditions for removing zinc from the dust include temperature in the range 1000-1150°C, inert gas atmosphere and furnace dust fraction in the furnace dust-manganese ore mixture above 60%. In the sintering of manganese ore with addition of manganese dust in the sintering pot, zinc was reoxidised and deposited in the sinter bed. Removal of zinc in the sintering pot tests was in the range 4-17%. Up to 30% zinc removal was achieved from the bottom layer of the sinter bed. It can be concluded that zinc removal will be low during the processing of manganese furnace dust in the sinter plant. The zinc removal rate will be the highest when pelletised manganese furnace dust is added to the bottom layer of the sintering bed.

Jan 1, 2007

O.F.S. Branch, Welkom Minutes of a Committee Meeting held in the V.LP. Lounge of the Welkom Club on Tuesday, 26th June, 1973, at 5.00 p.m. Present Mr C. J. Isaac (in the Chair), Mr D. A. Smith, Mr G. Young,

Jan 1, 1974

By P. N. Lategan

Mining companies are challenged with increased difficulty in delivering capital projects on schedule and within budget. In 2005, PricewaterhouseCoopers global review of major capital projects in the mining industry only 2.5% of projects could be defined as successful when assessed across the four critical dimensions of scope, cost, schedule and business benefits. Thus 97.5% of major mining capital projects were not successful according to the criteria PricewaterhouseCoopers used. Normally if a project fails on all these criteria it indicates scope creep. Scope creep refers to the change in a project's scope after the project work has started. As a result, the projects drift away from their original design, timeline, and budget, and as a consequence destroy business benefits. The major reasons for scope creep are poor change control and the lack of proper front end loading. Change control and front end loading are based on project processes in the planning and monitoring & control process group of the Project Management Body of Knowledge1 (PMBOK). This paper will focus on key factors to consider during project scheduling/planning with special reference to cost and schedule (using Microsoft Project as a tool although the principal is universal)

Jan 1, 2009

By M. Paricheh, M. Rahmanpour

"The cost efficiency and high reliability of semi-mobile or combined in-pit crushing-conveying (IPCC) and truck systems, compared to conventional truck-shovel systems alone, make them more attractive for use in modern mining operations. Semi-mobile systems, which are the most common systems in open-pit mining, combine the advantages of both systems such that fewer trucks are required, operating costs are lowered, and the operation is environmentally sound. One major aspect of utilizing this system is determining the location of the in-pit crusher and the timing of relocations. Facility location models are rarely used in the mining sector, but these models may be used for solving the in-pit crusher location problem. To this end, the main parameters affecting the IPCC location in open pit mines are reviewed and examples given of how they are applied to a dynamic location-relocation problem. Subsequently, the model is implemented for Sungun copper mine in Iran and the number and the exact time of relocations of the IPCC units determined. IntroductionNowadays, compared to the last century, metal prices are more volatile, average and cut-off grades have decreased, and stripping ratios increased. From a mining engineering point of view, many ore deposits with simple access and low capital and operating costs have been exhausted. The remaining deposits are located at depth, with no easy access, which requires high initial capital costs (Osanloo, 2012). Mining at great depths and high tonnages is possible only through open pit mining. Today, more than 80% of open pit mines in the world use a shovel-truck system for loading-hauling operations (Osanloo, 2010).With increasing depth, haulage distances increase and the number of loads per truck decreases. As a result, fuel, tyre, and depreciation costs per ton increase. Owing to these factors, open pit mining at great depth (300 to 1000 m) using shovel-truck systems faces some technical and economic problems. In-pit crushing-conveying (IPCC) systems have been known in the mining industry for many decades. The idea was introduced in 1956 in Germany. Today, the cost efficiency and high reliability of IPCC make it more appealing than conventional shovel-truck operation, especially in longer life projects with lengthy transportation distances and high production rates (Koehler, 2003). Since 1956, different aspects of this system have been reviewed by many researchers. Barua and Lanergan (1985) developed a computer program that compares the tonnage aspects of various conveyor layouts. They believed that to maximize the economic benefit of lower haulage costs associated with in-pit conveying, one must first minimize the cost of the flatter slope, which is expressed in terms of additional stripping or tied-up ore. Dos Santos and Stanisic (1987) evaluated the design of a high-angle conveyor at the Majdanpek copper mine. Then, Sturgul (1987) applied GPSS (general purpose simulation system) to find the best location of an in-pit crusher."

Jan 1, 2017

By A. Fahimifar, H. Soroush

Abstract: In order to develop non-destructive methods in studying physical and mechanical properties of rock and replacing them with difficult and expensive static methods, several ultrasonic tests were carried out on cylindrical rock specimens in accordance with the ISRM suggested methods and velocity of P and S waves were determined. Also, density, porosity, water absorption, uniaxial compressive strength and indirect tensile strength were determined for each specimen in accordance with ISRM suggested methods. According to above tests static and dynamic elastic constants were calculated After statistical analysis of data obtained from tests, the relationships between velocity of elastic waves and physical or mechanical parameters were determined and some equations were obtained. Also similar analyses were performed on static and dynamic constants and some equations were extracted. Using these equations, the physical and mechanical parameters of rock and also static elastic constants can be estimated by conducting simple and quick tests (i.e. ultrasonic tests). Abriß: Um zu entwickeln, die zerstörungsfreien Methoden für Studieren die physischen und mechanischen Eigentümer von Steinen und auch ist für Ersetzen diese Methoden mit schwierigen teuren statischen Methoden, mehrere altrasonic Prüfungen auf zylindrischen Steinproben gemäß ISRM anregenden Methoden und den Geschwindigkeiten von S und P Wellen bestimmt worden sind durchgeführt worden. Außer der Dichtheit und der Porosität betonen Wasser Aufnahme und monoaxial Widerstand und dehnbaren indirekten Widerstand jeder Probe betreffend der erhaltenen Ergebnisse die atmosphärische Aufladung sind bestimmt worden und die dynamischen Faktoren der Steine sind kalkuliert worden. Nachdem statistische Analyse die Korrelation der Ergebnisse zwischen der Geschwindigkeit elastischer Wellen und mechanischer und physischer Eigentümer der Steine erhalten worden ist, und mehrere Verhältnisse sind vorgeschlagen worden. Eine ähnliche Analyse ist auf atmosphärischer Aufladung und dynamischen Faktoren durchgeführt worden und einige Verhältnisse sind erhalten worden. Mit Hilfe dieser Verhältnisse die physischen und mathematischen Eigentümer von Steinen und auch können die Statistik Faktoren durch einfachen und schnellen altrasonic Prüfungen erhalten werden. Resume: Puor le development des method non-destructive et evaluuation des propietes physical et mechanical des rock et superseding avec les methods dificzle et cher statique, c‘ est fait plusieur essayes ultrasonique sur les echantillons cylinrique et par a port le proposale TSRM et le vittesse des ondes P et S et densite et porosite et absorption des eaux le resistant de pression uniaxial et resistance de chaque echantillon est determinee. A la fin en base des resultat obtenue les constant statique et dynamique des roches sont calcule. Apres les analyses statistiquc sur les resultat obtenue du les essaybs, c‘ etait produit les relation entre les viptesse les ondes elastique et les proprietes physic et mechanicue des roches et c est propose quelque relations. Aussi le meme enterpretation sur les constant statique etdinamique. En possezon de ces relations, les spesificatio physique, aussi on peut trouver leur constant statique, avel les essayes sample et raptid a d ultrasonique.

Jan 1, 2003

By Baojun Zhao

Primary lead production using the lead blast furnace in conventional practice is carried out using sinter feed. At YMG, China, the sinter plant has been replaced with a lead ISASMELT furnace. The ISASMELT furnace produces lead bullion plus a high-lead slag, which is cast into lumps to provide a suitable feed for the blast furnace. In the present study the relative microstructures and reduction characteristics of industrial lead sinters and synthetic ISASMELT slag in CO/CO2 gas mixtures have been measured and compared. The microstructure and property changes, and the mechanisms of reduction in each case are examined and discussed. The results of the study are used to explain the successful implementation of cast slag feed in commercial ISASMELT- lead blast furnace practice. Key words: lead slag, lead sinter, lead blast furnace, reduction kinetics and mechanisms

Jan 1, 2008

By L. Forsbacka, M. Nakamoto, L. Holappa

Viscosity of the slag is one of the central parameters when producing FeCr in submerged arc furnaces. It contributes to smelting behaviour and reduction kinetics of chromite ore as well as to the Cr recovery by influencing the separation of dispersed metal droplets from the slag. A typical FeCr process slag contains 5-10pct chromium oxides, CrO and CrO1.5. The neural network computation was applied to the evaluation of viscosity for slags containing chromium oxides, and the prediction of viscosity in FeCr process slag was conducted. The main results in this estimation were that the chromium oxides in FeCr process slag lower its viscosity, and that the effect of CrO on the viscosity decrease is greater than that of CrO1.5.

Jan 1, 2007

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 K Kongolo, M K. Kalenga

It is well known that the electrochemical precipitation of metals from aqueous solutions is conducted by the electrochemical standard potential scale. This scale indicates the order of nobility of different metals. Consequently, the standard potential scale shows the nocivity of metals when they are present as impurities in aqueous solutions containing metals. In the hydrometallurgy of cobalt, nickel and zinc are co-deposited during cobalt electrodeposition. Nickel has almost the same chemical, physical and electrochemical properties as cobalt. Furthermore, the electrochemical potential of nickel is relatively higher than that of cobalt. For this reason nickel is preferentially reduced at the cathode in the presence of cobalt. The presence of small amounts of zinc in solution leads to contamination of cobalt electro won. In spite of its lower electrochemical potential in comparison to cobalt, zinc is reduced on the cathode because of its higher hydrogen-overvoltage. But, in the hydrometallurgy of zinc, small amounts of cobalt present into solution will contaminates the zinc reduced at the cathode. This is easily explained by the fact that cobalt is more electropositive than zinc. The co-deposition mechanism of sulphur at the cathode is not yet well understood. Great attention has to be paid to the mechanism of co-deposition of sulphur during cobalt electrolysis..This work aimed to investigate the influence of some parameters on the co-deposition of nickel, zinc and sulphur during cobalt electrowinning. The following parameters have been investigated : Co2+ concentration in the electrolyte, current density and ammonium sulphate (NH4)2SO4 additions. It has been established that important nickel, zinc and sulphur co-deposition takes place at relatively low Co2+ concentration in solution. The behaviour of these elements with regard to the cathodic phenomena has been established.

Jan 1, 2005

By D. Janicijevic

This paper describes the process of scraper winch pull force measurement and shows the results of the actual winch pull force in extreme stall situations as well as during the face and gulley cleaning. It was found that by slowing down the motor and causing it to slip, torque up to 3.5 times higher than the nominal can be developed, resulting in the same increase of winch pull force. On the other hand, measurements of the actual force needed for cleaning of the face and the gully have shown that the currently used winches are too powerful. The extra torque that can be developed by the already too powerful winch motor poses a significant danger and necessitates the implementation of measures that will eliminate this risk.

Jan 1, 2008

By N. Mulaudzi, S. Archer

"Direct cobalt electrowinning was developed to produce unrefined cobalt metal as an alternative to producing a mixed hydroxide product (MHP), which is the common cobalt intermediate product in African Copperbelt operations. MHP is preferred due to the high cost of producing high-grade cobalt cathode. Direct cobalt electrowinning test work results have shown that the purity of the unrefined cobalt metal produced from a low-grade copper solvent-extraction raffinate stream was ~97% (w/w), which is significantly higher than the MHP purity (up to 45% (w/w) Co). The current study investigates whether direct cobalt electrowinning would increase the profitability of African Copperbelt copper–cobalt oxide operations, when compared with the MHP flowsheet. An order-of-magnitude economic evaluation was conducted using dynamic differential discounted cash flow models on a “bare-bones” basis, using a 10% discount rate. Three variables were evaluated, namely; reagent utilisation extents, precipitation extents and filter-press wash efficiency. Multivariable risk analysis was also conducted using the Monte Carlo simulation technique to understand the impact of key project drivers. The financial study results indicated that a direct cobalt electrowinning flowsheet could potentially result in a higher mean net present value (NPV) compared with the MHP flowsheet. Cobalt recovery was found to have the most significant impact on the NPV. In addition to increased profitability of African Copperbelt operations, direct cobalt electrowinning has the potential to reduce the environmental footprint of operations as well as addressing the Democratic Republic of Congo government’s drive towards export of higher value metal products instead of low-grade intermediates."

Jan 1, 2015

An efficient and portable mathematical model has been developed for simulating heat transfer in six-in-line slag-resistance-heating electric furnaces for smelting sulphide ores to produce base metals and platinum group metals. This model is a steady-state one relating furnace conditions and performances to various control and input parameters. Some transient effects occurring in electric furnaces are neglected for computation efficiency. This article describes the model development and modelling results. The present model is capable of predicting: (i) temperatures at various locations in a six-in-line furnace, such as slag bath, matte bath, solid charge, freeboard space, freeze lining, cooling water, and air gaps between solid material components, etc. (ii) freeze lining thickness, (iii)smelting rate, and (iv) heat loss rate, etc. A typical feature of the model is that it is easily portable to different application platforms and sufficiently efficient with execution times less than a few seconds. Therefore, it is possible to apply the model for online prediction and control of heat transfer and freeze lining thickness in industrial electric furnaces.

Jan 1, 2011

By D. Norval

Keywords: Pyrometallurgy, slag, metal, entrained, granulation, ferromanganese Water granulation of certain slags with high metal entrainment has customarily not been practised, not only due to the belief that such processes are too dangerous and unproven in the pyrometallurgical industry, but also that it might not be economically viable or environmentally acceptable. General slag granulation, on the other hand, is extensively applied, although in some cases crudely, with disastrous effects, as a result of not recognising the high heat capacities prevalent in slags. Thus, purpose-designed granulation and solidification processes are discussed, taking into account specific applications and the individual signatures of alloys and slags, emphasising that no slag, matte, or alloy responds in similar fashion to a granulation practice. This paper addresses three issues, namely: ? Water-granulation of BOF steel slag, without processing it to render it environmentally safe, physically and chemically acceptable for use by the construction industry, and the process economical ? Processing air-cooled BOF steel slag to change its physical and chemical properties to be acceptable for various uses and extracting metallic and bound iron ? Processing air-cooled or molten manganese slag to lower its manganese content to a level that is acceptable from an environmental and health point of view, and extracting FeMn-alloy of acceptable composition. The latter process culminated in a patented process to extract FeMn from air-cooled and molten manganese slag, and, at the same time, produce a hydraulic (cementitious) slag, thus transforming a possible hazardous by-product into virtually 100% saleable products.

Jan 1, 2011

By B. Leong, H. Joubert

Keywords: Pyrometallurgy, furnace, auxiliary equipment, copper slag launders Pyromet has designed copper launders for tapping slag. What makes Pyromet?s launder design innovative and safe is that it does not have any cooling water channels underneath the launder runner, whilst achieving effective cooling of the runner. If matte burn-throughs were to occur through the launder runner, the risk of damaging water channels and the risk of explosions are reduced. In addition, since the cooling water channels are not harmed, the launder is easily repairable and reusable. Pyromet makes use of Finite Element Analysis to optimize the launder geometry to ensure that sufficient energy is removed from the centre of the launder. Factors considered during the launder design include the suitability of the geometry to the client?s needs, experience from existing installations, and ease of fabrication. Pyromet goes so far as to develop procedures for fabricators to ensure that fabrication issues do not compromise the functionality of the launder. When launder orders are received by Pyromet, the entire fabrication process and the functioning of the launders during operations are monitored to ensure that the launder designs are continuously improving with every installation.

Jan 1, 2006

The paper examines the design issues associated with the integration of mineral processing within underground mining systems. It demonstrates conceptual integrated system design options appropriate to a range of geological scenarios. Particular reference is then given to a case study of stoping in narrow base metal veins. The performance of such integrated systems in terms of productivity, economic and environmental criteria is demonstrated by means of simulation. Particular attention is given to the potential benefits to mine waste management. Processing technologies appear to offer genuine potential benefit, whilst underground mining methods may need to evolve further to facilitate full integration. This paper is based on industry supported research aimed at developing selective and clean underground mining systems.

Jan 1, 2003

Threshold blasting involves the use of small amounts of high explosive to break and fragment hard rock without having to evacuate mining personnel. The method is easily assimilated and effective in rockbreaking, but requires rigid control on drilling, charging and timing. Current underground trials are aimed at fine-tuning the amount of explosive energy and blast hole geometry to allow the firing of multiple sets of shot holes in a continuous manner. Through correct procedures, the after-blast fumes, dust and fly rock can be contained so as to provide a safe working environment. Threshold blasting hugely reduces the volumes of explosives used in mining and brings to maturity the potential of the process begun by Alfred Nobel when he introduced nitroglycerine, and later dynamite, to mining. Its key contribution is its enabling of continuous mining operations with well understood and relatively low cost technologies. The use of batch blasting, employing large burdens holds the greatest potential for delivering high flow rates of ore at minimal cost. There is good potential for rapid evolution of the concept.

Jan 1, 2002

By M. Hermanus

1. INTRODUCTION It gives me great pleasure to extend my warmest greetings to everyone attending the 30th International Conference of Safety in Mines Research Institutes. I would also like to bid a special welcome to all of the international delegates who have travelled to Johannesburg to take part in what surely be a most rewarding session of deliberations. As you come together over next four days, you will have a wonderful opportunity to exchange ideas and information on strategies and practices for the implementation of sustainable patterns of development. The objectives of this meeting are both timely and far-reaching, as countries around the globe work towards the sustainable use of the world resources. Each of you brings a high level of expertise to these deliberations. I know that you will make the most of this opportunity to address the challenges and opportunities to highlight the most innovative and technologically efficient methods of social protection in order to ensure an increase in the quality of life, health, safety and living environment for the peoples of the Africa. Our country, although endowed with an immense and diverse array of mineral deposits, is perhaps best known in the mining industry for the fact that it is the world’s biggest producer of gold. Although South African gold production has declined over the past years and the industry faces serious problems, it is a myth that the South African industry is moribund. There is a new energy coursing through the South African producers which will ensure their powerful presence for many years to come, based not only on their domestic production but also and probably increasingly on their external operations. Africa features prominently in the latter category.

Jan 1, 2003

A physical modelling study has been carried out to simulate the slag-metal dispersion induced by a high-strength bottom gas injection. Water and kerosene were utilized to simulate metal and slag respectively. A water model of CLU (Creusot-Loire Uddeholm)vessel was used with three different nozzle orientations, namely, off-centre, triangular off-centre and centre. The gas flow rates changed from 0.00599 m3/s to 0.01081 m3/s. Height of heavy and light phases was kept fixed at 0.23 m and 0.02 m respectively. The dispersed phase hold-up was determined at various axial and radial distances, gas flow rates, and tuyere configurations. The observations revealed that at a fixed gas injection rate, as the vertical distance increased in the centerline, straight off-centre orientation resulted in greater dispersed phase hold-up values than those of the centre configuration and the triangular off-centre orientation. The dispersed phase hold-up was found to increase with gas injection rate and decreased with axial distance. The variation of the dispersed phase hold-up with the dimensionless axial distance and the gas injection rate was correlated by using the modified Froude number. The experimental values of the dispersed phase hold-up were found to be in reasonable agreement with the correlated values obtained from the modelling equations. The findings of the present study may be utilized in the ferroalloy refining vessels in terms of designing tuyere locations for optimum processing conditions.

Jan 1, 2004

By M. Syamujulu

In 1994, Nkana smelter commissioned a multimillion US Dollar Chilean Teniente converter (CT) in its operations in order to improve its smelting technological base. The main objective was to reduce the overall smelting energy costs and increase the sulphur capture for sulphuric acid production to support the company?s leaching operations at Nchanga tailings leach plant. A decade of CT operations have since ensued following its installation and start-up. This paper provides a technical and operational audit of the performance of the CT in the first 10 years of its operations at Nkana smelter.

Jan 1, 2005

The 105th Annual General Meeting of The South African Institute of Mining and Metallurgy was held in the J.C. Lemmer Auditorium, SA National Museum of Military History, 22Erlswold Way, Saxonwold, Johannesburg on Thursday, 8thAugust, 2002. 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: Mzolisi Diliza, Chief Executive, Chamber of Mines of South Africa Dawie van Wyk and Rod Tucker, Vice-presidents, The Geological Society of South Africa Vaughan Townsend, President, Institute of Certificated Mechanical and Electrical Engineers, South Africa Karel Landman, President, Institute of Mine Surveyors of South Africa Frik Grobbelaar, South African Colliery Managers? Association Pierre Ballot, President, South African Institute of Electrical Engineers Trueman Goba, President, South African Institution of Civil Engineers

Jan 1, 2002