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By O. Schnake, M. Isakson, C. A. Landolt

The paper presents the conceptual basis for the development of an Activity Based Costing system (ABC) for the analysis and estimation of process costs in mining and metallurgy. In particular, it discusses three major thrusts towards attaining increased efficiency in extraction and processing systems: (a) understanding the link between process and expenses, (b) identifying the chemical and physical factors that govern process costs and ( c) using process and cost models of the production systems. The authors have developed computer techniques to analyze data from conventional accounting and apply them to the development of process based ABC systems. The cost causing activities are linked to management units patterned after the organizational structure of the production system. All costs are associated with specific process functions such as charge preparation, smelting, refining, etc. The level of detail is determined by the quality of data available in conventional accounting systems. The system permits data analysis of historical cases and the projection of costs for new production schemes. Results can be presented in various levels of aggregation, following organizational and/or functional structures. The outputs of the system are tabular and graphical, typically following Pareto analysis concepts.

Jan 1, 2007

By Norman Orr, J. W. Gregg, Jack Wahl

The Pembina Cardium pool is a low permeability, stratified, solution-gas drive reservoir. Water-flooding has proven to be an effective means of pressure maintenance for all areas of the pool in which an economic rate of water injection can be maintained. The majority of water injection wells in the pool are converted oil well~ with capacities greater than 100 millidarcy-feet. If the average injection rate per unit of capacity can be in-creased the lower capacity areas of the pool can be economically flooded. Theory, laboratory work, and two . early miscible-flooding projects with-in the pool suggested that average water injection rates for converted wells could be increased two to three-fold by the initial injection of natural gas liquids and natural gas. How-ever, these two early projects received volumes of natural gas liquid!:' and high-pressure natural gas which would be economically prohibitive for routine stimulation. Area D, one of the Five-

Jan 1, 1962

By H. Oterdoom, S. Pilger, T. P. Bui, J. Rotarius

"Most FeNi furnaces used to rely on post-combustion and off-gas cooling inside the furnace to eliminate the produced CO gas, and control the off gas temperature. As furnace load, capacity, and thus gas volumes increased over the years, this led to increased instabilities that can cause problems in controlling the operation. Some of the large capacity furnaces nowadays work with partial or full combustion outside the furnace, more similar to the steel industry. Forced combustion with or without enriched air and other additions can support in controlling post-combustion, stabilizing and even reducing off gas amounts, and affecting composition. This paper presents some of the possibilities and advantages of having a specially designed post-combustion system for the FeNi laterite industry, but that could also be applied to other processes as well.Large Scale Furnaces In the FeNi industry, the Rotary Kiln Electric Furnace (RKEF) process is still going strong in spite of continuous hope that hydrometallurgical processes will one day make the RKEF plant obsolete. Within the pyrometallurgical plants there is a continuous trend for larger scale furnaces. The development for a number of furnaces that were started before 1985 and increased capacity by “natural growth” is given in Figure 1. Natural growth refers to the development of the plants that after having mastered a certain level of operation, were ready for a higher load that could be installed either with a new furnace on the same site, or during a revamp. The advantages of natural growth are numerous, for example: •,Deep knowledge of the ore and its’ behavior, no need for testing, and little risk of surprises. •,Mining, laboratory, equipment, etc. is all proven technology for the conditions on site. •,Starting a furnace with increased capacity is a re-start, not a green-field commissioning. •,Typically, when increasing the production capacity of an existing plant, not the entire plant is commissioned for the first time, but only a part. In the FeNi laterite industry for example, the kilns may already have had the capacity to provide enough material."

Jan 1, 2017

By G. Forté, R. Girard

The Alcan Bayer Process Experimental Centre (BEC) is an essential development tool for the Bauxite & Alumina researchers at the Alcan Arvida Research and Development Centre in Jonquiere, Quebec. Between the laboratory tests and the industrial prototypes or the industrial applications, the BEC is a key element for technology transfers. The Bayer process is the extraction of aluminium oxide (or alumina) from the bauxite ore. The Bayer Experimental Centre's history and flowsheet are presented. The major pieces of equipment are described. Safety and design considerations are presented. Finally, examples of applications, double digestion and pressure decantation, are briefly described.

Jan 1, 2004

By P. S. Arthur

The copper I SAS MELT? process is a submerged lance bath smelting technology. In the 20 years since the process was first demonstrated on a semicommercial scale at Mount Isa in north-west Queensland, Australia, copper ISASMELT? plants have been constructed to treat concentrates or secondary raw materials around the world. The process is operating in smelters in Australia, the USA, Belgium, India, Germany, China and Zambia. ISASMELT? plants have been installed to improve the environmental performance of operating smelters and reduce costs for smelting companies. A new copper furnace is being commissioned at Southern Peru Copper Corporation in early 2007, while more furnaces are under design for installation in Kazakhstan and Peru. Copper ISASMEL T? plants are supplied as complete technology packages including engineering design services for the furnace and key ancillaries, supply of core equipment, provision of intensive training programs in operating plant environments and commissioning assistance services. The proven technology transfer process ensures successful implementation of submerged lance bath smelting into large scale plants. This paper summarises developments at recently constructed copper ISASMELT? plants.

Jan 1, 2007

By Dharmendr Kumar, Pradip, Sivakumar Subramanian, Beena Rai, Venugopal Tammishetti

The separation efficiency in a mineral processing plant is generally assessed and reported in terms of elemental assays constituting the minerals of interest. However, different minerals comprising of same elements behave differently under similar process conditions. Thus, it is imperative to track the mineral composition thank elemental composition of different streams in a processing plant. The availability of automated mineral analyzers such as QEMSCAN and TESCAN in recent times has made it possible. However, due to the high cost and expertise required, their adaptation in day to day monitoring of operations is not yet a common place. X-ray diffraction (XRD) profile fitting (Rietveld Refinement) is another technique which can provide estimates of mineral proportions in a sample. The results of Rietveld Refinement however are affected by coating of fines on coarse particles, method of sample preparation, particle size distribution of sample, elemental substitution in mineral crystal lattice. In the present work, we propose a simple and efficient method for quantitative estimation of minerals in iron ores using elemental assays and thermo-gravimetry analysis data. The minerals (hematite, goethite, gibbsite, kaolin and quartz) are identified using powder XRD analysis. It is also observed that goethite contains Al substitution in the crystal lattice. The samples were analyzed for %Fe, %Al2O3 and %Silica using chemical analysis. The measured Loss on Ignition (LOI) in the sample is contributed from goethite, gibbsite and kaolinite phases. LOI from gibbsite and goethite occur in temperature range 250–350°C and LOI from kaolinite occur in temperature range 400–700°C. According, LOI are determined in two different temperature ranges that are 100–400°C and 400–850°C. We have used the data to successfully determine the mineral compositions of iron ore samples. We have also employed a data reconciliation algorithm on the calculated data for further improvement and consistency of our results. Our method is very convenient for quick estimation of mineral proportions in a sample. The proposed method can also be used for quantitative phase estimation in bauxite ores and red muds.

Jan 1, 2016

By M. A. Hararah, T. Neesse, M. G. Farghaly, G. Proellss, P. Kaniut, W. Rubarth

ABSTRACT: This paper presents two new options for hydrocyclone control. Volume split control using a control valve in the overflow is applied for the stabilization of separation results at changing feed conditions. Controlled water injection to the conical part of the cyclone leads to the reduction of fine particles in the underflow. Hydrocyclone monitoring in both cases is performed by optical sensors that indicate the spray angle of the underflow. Applications in mineral processing for desliming, classification in closed-circuit grinding, and dewatering are demonstrated.

Jan 1, 2011

By C. J. Preston, R. E. Ström, G. R. Baiden

"On January 1st 1996 Inco Limited, Tamrock OY, Dyno Explosives Group and CANMET formed a consortium for the development of robotic mining equipment. This project is a five year research and development agreement that combines the talents of the above organizations to facilitate the creation of mining equipment and systems for robotic mining.The projects are based on the communication system developed by Inco Mines Research and currently sold and marketed by Automated Mining Systems Limited. Main projects include the development and implementation of a positioning and navigation module (including a software mapping system that will be inherent to each piece of equipment), robotic systems for development and mining, and software systems to support the use of this equipment. Included in the program is the establishment of a test mine, at Inco’s 175 ore- body at Copper Cliff. This facility will allow collaboration of companies and research organizations for the design and testing of techniques and equipment for Robotic mining.This paper discusses the creation of this new research alliance, the Mining Automation Program or MAP."

Jan 1, 1997

By S. D. Anitha Kumari, T. G. Sitharam

"The huge urbanisation of the world cities have invariably resulted in enormous requirements of development in transport and other facilities. As the surface space available for the construction of these infrastructural facilities is found to be inadequate, underground space is widely used recently for this purpose. However, to understand the behaviour of these underground structures through experiments under various loading conditions is not practically feasible. Hence numerical methods have widely been used to model these structures and predict their behaviour. The underground structures generally rest on soil or rock. Depending upon the properties of the material surrounding the tunnel, the deformation pattern and the stress contours vary. If the tunnels are placed on soft ground at a shallow depth, the presence of existing structures will add to the stresses and strains developed. In the case of densely populated cities, tunnelling operation may result in huge damages if the settlements are not within the desirable limits. This may in turn lead to the collapse of the tunnel along with adjoining structures. So the determination of stress levels associated with the yield of wall due to excavation is very important and necessary supports and reinforcement should be provided. Numerical simulations using discrete element method (DEM) and finite element method (FEM) have been done to understand the stress variation around single and twin tunnels. Studies are also done to quantify the improvement of stability on the introduction of lining around the tunnels in a weak cemented soil mass like sandstone.INTRODUCTIONMost of the life line facilities which include pipelines for electricity, water, communication, sewage, gas, roads, metro, utility tunnels etc in modern urban areas are underground structures. Infrastructure development is crucial for any city and sustainable development urges for underground constructions. Accordingly, there is already a great demand for tunnels to be constructed in difficult and crowded urban settings. This results in the fact that a large number of risk factors are associated with tunnels in these densely populated urban areas. These constraints pose threats to tunnel construction and also demands for minimal disturbance to the public and to the surrounding utilities. One of the most important factor to be considered while designing an underground structure is its stability with respect to the surrounding medium and adjoining existing structures. In this study, a comprehensive presentation of the numerical modeling of single and twin tunnels adopting two different methods is presented."

Jan 1, 2015

By L. Bos

The availability and reliability of large grinding mills and their Gearless Mill Drives (GMDs) are of paramount importance for the grinding process. Although GMDs have been in service for decades, and are known for their operational efficiency (reliability and robustness with reduced operating cost per ton), compared to conventional drives, in the last decade due to certain reasons some failures led to serious unscheduled shutdowns and significant insurance events. The majority of these notable "insured" failures have happened on GMDs installed on relatively large mills, as the financial impact of a failure is proportional to the through-put of the mill. Despite the occurrences of these events, as mining operations are driven by lower ore grades and the ability to continue reducing operating costs per ton, the trend for having larger mills is still very present and there is no reason why this trend should not continue. It is obvious that if not handled correctly, the possibility of large value GMD loss events, coupled with the continuing increase in mill size or required availability and reliability targets, could potentially lead to major conflicts as it becomes difficult for the insurance companies to judge the risk and hence may result in hesitation to insure these grinding circuits. This paper will not only describe the conflicting situation from both an insurer's perspective and from an equipment supplier's perspective, but also how these conflicting challenges can be successfully mastered. It has to be noted that not only the mining companies themselves, but also their insurance companies and the involved equipment suppliers have a common interest: to reach the highest availability and reliability in order to avoid or at least minimize unscheduled shut down times, and most importantly prevent unplanned events that result in extended production stoppages or reductions in through-put of GMD driven mills. From the very beginning onwards, the complete service concept together with emergency plans must be integrated on every level in the design of the grinding circuit. This approach must be implemented continuously and without compromises by all involved parties during all following stages, such as basic design, detail design, manufacturing, quality inspection and testing, packing, transportation, storage, installation, commissioning, operation and maintenance. The concept of formal risk analysis related to mill operations, maintenance and spare parts strategies must be an integral part of mining companies? decisions related to the selection for installation and continued use of large mills powered by GMDs. The service concept in place for operating mills shall also have a clear focus on very early detection of any abnormalities, so that the risk can be mitigated and unscheduled shutdown times avoided. However, if a major failure occurs, then procedures and tools shall already be available in order to ensure that production impact is minimized.

Jan 1, 2012

By A. Warczok

Metal losses in discard slag are the main factor determining overall recovery. The metals are present both in dissolved form and as matte or metallic inclusions, varying in size from 2 to 1000 µm. Pyrometallurgical slag cleaning usually consists of heating the slag, reduction of oxides and settling of matte/metal droplets. Heating the slag decreases viscosity and accelerates reactions. Reduction of magnetite liberates inclusions and facilitates co-reduction of dissolved metal oxides. A significant amount of the matte and metal is present as very fine metallic inclusions, too small for settling. The coalescence of these matte or metal inclusions is required to remove them from the slag. The developed new concept of slag cleaning combines DC furnace technology with an extra magnetic field for vigorous slag stirring, enhancing mass transfer to the reductant surface, accelerating the rate of reduction, and destabilizing the emulsion of matte or metal inclusions. Intensive slag stirring increases the probability of collision of inclusions, will accelerate their growth and will therefore improve settling. The process is carried out in a patented DC channel furnace, where the liquid metal or matte layer acts as a cathode and the floating coke bed on the slag surface is the anode. In the first part of the furnace, a superimposed magnetic field induces a Lorentz's force causing the slag to start an intensive circular motion. The next furnace zone does not experience any stirring and is dedicated for quiet sedimentation of the inclusions. A mathematical model of gravitational coalescence combined with forced slag motion showed the possibilities of effective removal of copper matte inclusions. The results of laboratory pilot scale tests of continuous slag cleaning showed fast slag reduction and confirmed the improved matte removal from the slag. Conceptual analysis shows the potential use of the technology in various other non-ferrous industries, like for example nickel plants. It is also possible to use this technique batch wise.

Jan 1, 2007

By M. Somppi, D. Weirmeir, Z. Yamak

"Milling operations commonly employ activated carbon to capture complexed gold from lixiviants in leaching processes. As the carbon moves through pipes, pumps, vessels, kilns and other processes in the gold leaching circuit, this consumable may experience losses by various mechanisms like attrition, breakage, and rupturing. Whenever possible, capturing the fine gold-bearing carbon portion of this stream could provide value to milling operations at low capital cost and manageable financial risk. Identifying, testing, and validating the successful payback of a low-tech flocculant system is described. However, the work more closely explores a Monte Carlo risk-based methodology for understanding the potential payback of this project at various confidence levels – an approach that many improvement projects can follow where some level of uncertainty exists.INTRODUCTION Gold milling operations commonly employ activated carbon to adsorb gold from solutions. Normal handling causes the carbon particles from this material to abrade, break, rupture to a size that becomes too small for further use in the process. Operations often concentrate on capturing the fine particles because gold is associated with the carbon and this metal content can be a valuable revenue stream for toll processing. However, the small particle sizes become difficult to separate from the process and can ultimately leave the facility in the waste stream. Hence, operations often place a great deal of care in capturing as much fine carbon as possible by a variety of methods including using screens, settling tanks, and chemical methods. Retrofitting a circuit to capture more carbon fines is common but can expose the operation to financial risk. Approaching this potential improvement by leveraging a Monte Carlo methodology can be effective in understanding the risk and the associated payback of a project at various confidence levels. This method provides a strong framework for capital go-no-go decisions and the structure to validate the potential project success before implementation."

Jan 1, 2019

By M. Tanaka, H. Narita, K. Morisaku

"The selective separation of palladium (Pd), platinum (Pt), and rhodium (Rh) from a hydrochloric acid solution by solvent extraction was investigated using amide-type extractants, i.e., N,N,N’,N’-tetra-n-octyl-thiodiglycolamide (TDGA) and N-n-hexyl-bis(N-methyl-N-n-octyl-ethylamide) amine (BisAA). The separation experiments employed two separation schemes: (1) extraction of Pd with TDGA and that of Rh and Pt with BisAA; and (2) extraction of Rh, Pd, and Pt with BisAA. Separation scheme 1 achieved the highly selective separation of each metal. For separation scheme 2, Rh can be recovered prior to Pd and Pt, despite having a lower selectivity for Pd/Pt than separation scheme 1. INTRODUCTIONThe recent increase in the use of platinum group metals (PGMs) in industry (especially auto catalysts containing palladium (Pd), platinum (Pt), and rhodium (Rh)) has lead to their increasing waste; therefore, improvements in the recovery techniques for PGM have received significant attention. In metal refineries, PGMs are mainly separated and purified by solvent extraction (Cox, 2004). The extraction process used in INCO’s Acton precious metal refinery is one of the most famous commercial processes and is utilized worldwide. In this process, silver is first removed as a residue (AgCl), and then gold, Pd and Pt are extracted from hydrochloric acid (HCl) solutions using dibutylcarbitol (DBC), dialkylsulfide (DAS), and tri-n-butylphosphate (TBP), respectively. Finally, Rh remains in the raffinate (Barns & Edwards, 1982).The development of a successful solvent extraction process depends on the choice of the appropriate extractants. We have studied the extraction of PGM using N,N-disubstituted amide compounds (Narita, Tanaka, Morisaku, & Abe, 2004; Narita, Tanaka, Morisaku, & Tamura, 2006; Narita, Tanaka, & Morisaku, 2008a, 2008b). They are relatively stable against acids, and their metal extractability can be improved by changing the side chain length and/or introducing additional donor atoms like sulfur and nitrogen. We have recently found that thiodiglycolamide and an amide-containing tertiary amine have good extractabilities for Pd and Rh, respectively."

Jan 1, 2012

By X. -G. Chen, K. Liu, N. Parson

"Precipitation-strengthening 6xxx alloys are widely used for building and construction and automobile industries due to their high strength, good weldability and corrosion resistance. However, their elevated-temperature properties (250–300°C) decrease rapidly due to the fast-coarsening of precipitates. On the other hand, dispersoid-hardening is one of the most efficient approaches to improve the elevated-temperature properties. Therefore, the evolution of dispersoids during heat treatment in Al-Mg-Si-Mn alloys was investigated in the present work. Various heat treatments with temperatures ranging from 300–500°Cfor up to 24 hours were performed. Electrical conductivity and microhardness were measured while optical and scanning electron microscopy combined with image analysis, were used to characterize the dispersoids. Special emphasis was placed on the evolution of the size and number density of the dispersoids under different heat treatment parameters. It was found that dispersoids started to precipitate at 350°Cfor 1 hour. Nucleation and growth were the main mechanisms at temperatures up to 400°Cwhile coarsening occurred at temperatures above 450°C. The quantitative results indicated that dispersoids precipitation reached the optimum condition after treatment at 400°Cfor 2–4 hours with a fine size and high number density, resulting in the highest hardness.INTRODUCTIONThe precipitation-hardening 6xxx aluminum alloys with major alloying elements of Mg and Si are one of the most widely used aluminum alloys for building and construction and automobile industries (Dinaharan & Murugan, 2012). In recent years, there have been increasing demands for aluminum structural components to be used at elevated temperatures (250–300°C) for different applications. However, the mechanical properties of 6xxx alloys at elevated temperature are typically reduced due to the rapid coarsening of precipitates at 250–300°C. It has been reported that the yield strength (YS) of AA6061 in the peak-aged condition drops from 276 MPa at room temperature to only 30 MPa at 315°C(Kaufman, 1999). Therefore, it is a key concern to improve the elevated-temperature properties of 6xxx alloys to expand their range of applications."

Jan 1, 2018

By A. Staley, W. J. Cashwell, M. S. Moats

In the 1990’s, Técnicas Reunidas developed the Modified ZINCEX® Process to recover zinc from ores and secondary materials. The heart of this process was the use of solvent extraction to produce purified zinc electrolyte instead of traditional zinc dust cementation. This development was commercialized by Reunion Mining and Anglo American for primary ore at the Skorpion mine in Namibia with the first SHG zinc produced in May 2003. Horsehead Corporation through Horsehead Metal Products, Inc., its wholly owned subsidiary, is presently commercializing the MZP for the treatment of Waelz oxide. This paper will review open source information about the lessons learned and process modifications that have occurred at Skorpion over the past decade. It will also provide an update on Horsehead’s facility being constructed in Rutherford County, North Carolina.

Jan 1, 2014

By M. Jackson, R. McDonald, T. Osken, D. Robinson

"The addition of sulphidic materials in the leaching of nickel laterites has several potential benefits that include improvements in the rheological behaviour of the blends, reductions in the sulphuric acid and steam requirements, sweetening of the nickel grade of the combined feed material, and the option of using a range of sulphidic materials. The current study examines the oxidative processing of 30% w/w blends of nickel concentrate and nickel laterite ore at 250oC. In particular, the viability of using low oxygen overpressures was examined for significant amounts of nickel flotation concentrate, up to 12% w/w. Further to this the impact of process water quality, in particular the presence of chloride, upon the kinetics of extraction and the mineralogy of the residue were also investigated. This paper will present the results of preliminary work in this area.INTRODUCTIONThe use of sulphidic ore as a source of sulphuric acid during oxidative hydrometallurgical processing is not a novel idea and can be traced back over forty years (Seidel & Fitzhugh, 1968). A series of patents pertaining to application of this approach for laterite ores can be subsequently found (O’Neill, 1973; Opratko et al., 1974; Rodriguez, 2008a, 2008b; O’Callaghan, 2010; Liu et al., 2011) and a few of articles containing published data (Ferron & Fleming, 2004; Quinn et al., 2009). The use of pyrrhotite tailings as a source of sulphuric acid has also been employed for the leaching of converter slags (Perederiy et al., 2011).It is known that hydrometallurgical operations such as the HPAL plant at Murrin Murrin have added small amounts of sulphides as either transitional (mixed sulphide/oxide) ore or non-smeltable concentrate. This can improve the rheology (Rodriguez, 2009) and provide heat credits. However these plants are generally limited in their ability to add such materials due to their reducing nature and given under highly acidic conditions that the breakdown potential of the titanium used for the autoclave lining is significantly reduced. A suitable oxidant must therefore be present to ensure the potential remains sufficiently high."

Jan 1, 2012

By John D. Carriere, Jean Leung, Daniel. Laguitton, Michael .. J. Burrows

"The objective of this expert system application in a copper-zinc concentrator, is to increase the availability of assay data through substitution for erroneous data. The assay data is used by the Operations personnel and automatic process control strategies to control flotation circuit performance. Two online X-ray fluorescence analysis systems analyze 24 streams across four divisions to provide the required data. Data availability of individual streams average 90% while the resulting circuit availabilities are 70%. The unavailability of correct data results from mechanical, X-ray or process problems. The erroneous data can be identified by process experts using knowledge relating stream interdependencies and historical process behaviour. An expert system was devised to provide real time identification of erroneous data and substitute for that data with the ultimate aim of improving metallurgical response by both the operator and automatic control systems.The paper discusses the early development work and architecture of the knowledge base designed using Neuron Data's expert shell NEXPERT.INTRODUCTIONThis paper describes the early development of an expert system (ES) prototype at the Kidd Creek concentrator. The project is a joint undertaking of the Kidd Creek Division of Falconbridge Limited and CANMET. Kidd Creek entered into the project to apply heuristic rules to the XRF assay data to improve the metallurgical control of the flotation process by increasing availability of analysis data. This project provided a problem of suitable size and future expandability while making use of a wide base of in-house expertise and experience. Another important benefit is the introduction of expert system technology to the site providing tools and experience for future system selection and technology application. CANMET has an on-going interest in assessing various aspects of ES technology (hardware, software, knowledge engineering, integration) while addressing problems in process operations that could most readily benefit from the technique. CANMET's role in the project was to provide project assistance, financial support, substitution algorithm assistance and software for data substitution. The knowledge bases (rules) have now been completed and are to be tested in the online environment."

Jan 1, 1989

By G. E. Willey

F OR many years, only one grade of structural steel has been used in volume in Canada. Its characteristics have not been altered appreciably and its long use speaks well for its performance. This standard grade of structural steel may be bought and specified as C.S.A. G40.4 steel or the American equivalent, A.S.T.M. A7. The principal limitations and requirements of this specification are shown in Table I. Within the last five years there has been a growing awareness among the steel producers and steel fabricators that economic forces are at work which make desirable the availability of new and better grades of structural steel. Competition from other materials has increased. The use of concrete bridges and pre-stressed concrete beams is a prime example. New sources of steel from outside the country have become a threat to the Canadian industry and its high cost-price structure. The need for improved properties in the steel, to make possible technologic

Jan 1, 1962

By A. Lee Barrett

"THE COAL INDUSTRY of the United States• and Canada has made great progress in recent years. Coal mining in •the old days represented one of the most arduous tasks for labour and industry, but over the years great progress has been made in reducing the effort required from labour. Also, the tonnage produced per man, the cost of the coal per ton, and the overall safety of the operation, have been greatly improved.Looking back over the past fifty years:, the era can be divided into four principal parts: (a) hand-loading, (b) track mining methods, (c) off-track mining methods, and (d) continuous mining. For many years, all of the coal was won by hand-mining methods. The first forms of mechanization •resembled the move from the horse •and buggy to the automobile. Early track mechanical mining methods were usually adaptations of the direct methods involved in hand-mining, with each improvement directed toward some specific process. A revolutionary development came about with off-track mining methods. The first efforts in this direction were provided by off-track mechanical loading machines, which loaded the cars •on track and differed from conventional track mining methods only in that the loading machines themselves operated on the mine floor. With the advent -of the shuttle car about ten years ago, true off-track mining came into being, and real progress in this direction began to be made.At the present time we •are at the beginning of a new era -.the era of continuous mining. There will be a period of development with some time needed before the system is generally applied throughout the industry, but -already enough •has been done to indicate rather dearly what the future holds in this direction."

Jan 1, 1953

By W. N. Roman

This paper will examine the challenges involved in ventilating and cooling South African mines, with particular emphasis on solutions to the issues of heat (generally associated with depth), mechanization and energy efficiency. Comparisons will be made with other international mining areas. Some of the deepest mines in the world are to be found in the South African goldfields. The Mponeng mine is approaching 4,000 m below surface, with virgin rock temperatures (VRT) of between 60°C and 70°C. Mining at these depths has only been possible with the use of large refrigeration plants supplying cold air, water and ice to the workings. In the Bushveld Igneous Complex, where most of South Africa?s platinum mines are located, similar VRTs are being experienced at significantly shallower depths. This is due to the different geothermal properties of the host rock between the two areas. Existing mines are being forced to go deeper and new underground mines are being planned and constructed in other areas with widely differing thermal conditions. South African metal mining has traditionally been labour intensive for historical reasons as well as for the narrow tabular nature of many ore bodies. Due to cost pressures and labour problems, some mines have been investigating the possibility of using mechanized equipment, both diesel and electric, to increase production and to improve efficiency. Studies have been carried out to determine the effect of the additional equipment on the overall ventilation system and some of the conclusions are discussed. The use of diesel equipment adds heat and pollutants to the ventilation air but, although electrical equipment has a lesser effect on the ventilation systems, it is generally less favoured due to claims of lower flexibility/manoeuvrability. Mechanization holds the promise of more concentrated mining activities but, with higher localized ventilation and cooling needs. Systems which will control the provision of air and cooling more effectively are required and are being implemented. In the 1990s and early 2000s, the South African economy experienced significant growth which was not matched by the growth in infrastructure. Consequently, at present there is a shortage of electricity generation capacity which affects large industrial consumers, including mines. Increasing levels of heat and mechanization will require more electrical energy for ventilation and cooling. There are many initiatives underway to save power or to shift consumption to periods of national low demand and these will be described.

Aug 1, 2013