Search Documents

By P J. Ellen

The selection of the ore haulage system is a key decision made in the development of an underground mine. The haulage system is one of the components that define a mineÆs ability to respond to changes in mining inventory and market conditions. The complexity of this decision for Telfer Deeps was affected by the realisation during the feasibility process that the true scale of the potential underground mineralisation at Telfer was still to be quantified. This paper provides an overview of the process used in the Telfer Project Feasibility Study to select an ore haulage system for Telfer Deeps. The purpose is to highlight the value of impartially approaching tasks of this type with a robust process. The process should be able to respond to issues identified as the task progresses towards the objective of finding the best solution for an ore haulage system for the mine. For Telfer Deeps, this process resulted in the selection of a haulage system built around a shaft. The systems considered during the feasibility are discussed and the components of the haulage system constructed for Telfer Deeps are described.

Jan 1, 2005

The ore deposits investigated are composed primarily of hcmatite and can be grouped into three categories depending on the amount of leaching of silica and carbonate which has occurred from the original iron formation, and on the amount of recrystallization of the hematite. Minor constituents are magnetite. goethite, and quartz.Texturally. there are five different types of hematite, formed at different stages during the genesis of the ores.These are1. anhedral hematite grains formed by recrystallization of hematite already present in the original iron formation.2. hematite formed by martitization of euhedral magnetite, 3. massive aggregates of fine- to medium-grain hematite formed by recrystallization of (l) and (2).4. tabular or prismatic hematite grains occurring around the boundaries of the massive aggregates or martite euhedra. and in fractures and5. specular hematite. which is present in fractures in ore types (l) to (4).Minor and trace-element analyses, determined using an electron-probe microanalyser. indicated that only silica (less than 0·01 per cent) and cobalt (less than 0·002 per cent) were present in the magnetite and hematite from unaltered iron formation and in the hematite from the ores. Low concentrations of trace elements are typical of magnetite in ores formed as marine precipitates. On the basis of the analyses alone. it proved impossible to distinguish between the five hematite types. A determination of the variation in rare-earth trace element contents between iron oxides in the iron formation and iron oxides in the ores indicates that the rare earths were depleted during ore formation. A possible explanation is that they were removed in solution with silica as it was leached from the iron formation.

Jan 1, 1971

By Boger D. V

Two industrial case studies in which detailed investigation of the flow behaviour of mineral slurries is used to assess the feasibility of pipeline solid transport are described. The first example deals with the pumping of highly concentrated bauxite tailings to disposal, while the second exam- ple examines the possibility of transporting high-density Victorian brown coal slurries which previously has been thought as uneconomical. It is demonstrated that these typical solid handling problems can be solved by a good understanding of the rheology of suspensions.

Jan 1, 1989

By G MacSporran, I Sheppard

The practical application of LaneÆs theory on optimum cut-off grade policy has to date proved difficult for selective stoping in large-scale underground mining. The key to determining an optimum cut-off grade is the ability to rapidly perform complex mine layout designs combined with rapid output of multiple potential schedules. This paper describes aspects of the detailed investigation into estimating a practical static cut-off grade for the two main orebodies in Mount Isa MineÆs Enterprise Mine. Rule based automated scheduling software was used to evaluate thirteen different stoping layouts (including design infrastructure and capital development) of the Enterprise MineÆs two main orebodies, with over 200 schedules generated. The investigation illustrates the application of commercially available software to solve the problems of generating multiple cut-off grade stope designs and achieving the otherwise insurmountable task of rapidly generating and valuing multiple scenarios for each stoping layout. Each scenario was evaluated using modelled net cash flows of the mining, concentrating and smelting operations of the company and calculating NPV. The cut-off grade for each orebody was selected based on the cut-off grade that achieved maximum NPV û with an appropriate production rate. Underground mine scheduling is a complex task involving the adherence to a number of simple scheduling rules and the balancing of several competing drivers. The study also found that: while each scheduling rule itself is simple, the compounding complexities of their interaction preclude manual scheduling from being a realistic option. there is a maximum sustainable rate of production possible for any given stoping layout, and that the actual maximum production rate is also a function of the required number of years of sustainable production. the optimal cut-off grade was different for each orebody û a recognition of the impact of the different characteristics of each orebody.

Jan 1, 2003

By Greaves M. C, Amos M. D

A study was made of the instrumentation and technique of atomic absorption spectroscopy developed by Walsh of the Commonwealth Scientific and Industrial Research Organisation (CSIRO), Australia.The method was evaluated for the determination of silver in lead sulphide concentrate. The precision of the procedure developed is equal to that of the uncorrected fire assay method and the accuracy is greater.Brief mention is made of the use of this technique for the determination of silver and other elements in ores and concentrator products.

Jan 1, 1994

Coal production from Coal & Allied's Hunter Valley No 1 open cut is presently hauled 10 km by road to washing and train loading facilities at Liddell. This road haul, using bottom dump trucks on a bitumen sealed road, presents some unique earthmover tyre problems. Sound tyre management has controlled one potentially serious problem, that of heat damage, implicit with such a long haul. Tread abrasion or wear is therefore the limiting tyre performance factor. Study of abrasion mechanisms and interpretation of abrasion patterns has facilitated an understanding of the wear processes involved. This understand- ing has highlighted the importance of front tyre wheel alignment. The development of irregular wear is shown to be related to the mildness of the abrasion and methods of remving irregular wear are presented. In conclusion haulage by large off highway trucks on long sealed haul roads has been eooncoically and technically successful at Hunter Valley No 1. INTRODUCTION Hunter Valley No 1 (HVl) is a major open cut coal mine, owned and operated by Coal & Allied Operations Ltd, and located in the Hunter Valley of New South Wales. Present

Jan 1, 1982

The need for the hydraulic transportation of coal in the New South Wales coal industry, both from the coal face to the surface and from the coal mine to the consumer or the port for export, is explained. Details of research projects currently in progress and involving the hydraulic transportation of New South Wales coals are given together with information on the hydraulic transportation of coal in the United States of America. The potential of hydraulic transportation as a viable alternative to the proposed expansion and upgrading of the New South Wales railway system to meet the projected New South Wales coal production to the year 2000 is described.

Jan 1, 1980

By A Cooper

The current financial climate has given rise to fears that falling mineral prices and tight credit will force mining companies to cut back on production and new project development in a bid to cut costs and conserve cash. However, a prolonged squeeze on global supply can have only one result: a massive and potentially explosive demand for metals in the not-too-distant future. A resurgent global economy will also generate dramatic new demand for oil and energy, with a return to higher oil prices likely. How then should the mining industry plan for the future? In-pit crushing and conveying (IPCC) could lead the way as a partial or complete substitute for trucks. In 13 of 15 studies undertaken by Sandvik and Snowden, comparing IPCC with truck-optimised pit designs, IPCC generated operating savings ranging from US$0.18 to US$0.82 per tonne moved, compared to trucks. Trucks have higher operating, maintenance and energy costs than conveyors. New emission standards on diesel engines may make them more emission friendly but less efficient in terms of energy usage. With far more efficient energy use and cheaper operating costs per tonne moved than trucks, conveying offers an attractive alternative for the bad times ahead and into the apparent energy depleted future. When evaluating alternatives, a reasonable first step would be to conduct a scoping level study which analyses the differences in capital and operating costs between a truck and shovel operation and an IPCC solution. The study can also determine what type of IPCC is best suited to the particular mining application. The results can then be used to decide whether a more detailed study is justifiable. IPCC is a proven process that, with a fresh mindset, can make a significant improvement to mining operations. Sandvik (as an OEM with a full suite of IPCC equipment) can undertake these studies in ten working days in conjunction with Snowden or any other independent mine planner who knows how to schedule for IPCC. Because most mining industry personnel have been æborn and bredÆ on trucks and shovels û this paper focuses on some of the practical considerations necessary to make IPCC systems work that the Sandvik Technical Services Group has encountered during these studies.

Jan 1, 2009

Close spatial relationships between the deposits of the Etheridge Goldfield (23,000 kg of bullion) and various regional geological and geophysical features suggest that genesis of the ore deposits was a multi-stage process that started with magmatic and metamorphic stages in the mid-Proterozoic, climaxed with structural and hydrothermal stages in the late Palaeozoic and terminated with an oxidation enrichment stage in the Cainozoic. Acceptance of this hypothesis permits classification of the Georgetown region into areas likely to contain deposits of the Etheridge type and those unlikely to do so. Consequently there is little scop- for the discovery of extensions of this field. However, the stratigraphic interval between the source rocks of the Etheridge field and stratigraphically higher host rocks of the Croydon field may contain disseminated replacement gold deposits of the Carlin type. The potential host (pyritic carbonaceous, and locally dolomitic siltstone of the Candlow Formation) is locally faulted and cut by granitoids and the extension of a mineralised, long-standing zone of structural weakness.

Jan 1, 1980

By Hinchliffe WD, Griffin A

The desorption of gold from activated carbon is promoted by adding organic solvents to aqueous cyanide solutions. At 65-80¦ the elution of gold is fast and is not affected by water quality. The Micron Procedure involves pretreatment of the loaded carbon with NaCN/NaOH followed by elution with methanol vapour and condensate. Carbon is packed into a column above the distillation pot and acts as a fractionating column. Recovery of the methanol condensate leaves a methanol free concentrated gold solution and carbon containing

Jan 1, 1984

The subject of steel wire ropes covers such a wide range of points that it would be impossible to deal with it fully in one paper, and in view of the apparent scarcity of published information on the subject it is proposed in this paper to deal with those items which should give the mining engineer a better understanding of the basic factors which affect the design.selection, and use of ropes. The matter will be considered under the following headings:-1. Brief history of steel wire rope-making.2. Rope-making terms.3. Wire rope materials.4. Characteristics affecting economy, operating life, and serviceability of a rope.5. Properties of construction of rope, and stresses met with in wire ropes.6. Drum and sheave sizes and sheave bearing pressures.7. Storage, handling, and maintenance of ropes in service.8. Common factors affecting rope life, particularly winding and haulage ropes.9. Inspection of ropes.GENERALWire rope, which was invented for, and first applied to mine winding, has become an indispensable aUXiliary throughout the whole field of mining, be it for underground, open cut, or dredge work, as well as the requirements of transport and treatment of ores.Though wire ropes appear simple collections of wire and fibre, the demands made upon them are many, and the stresses and abuses to which they are exposed in service are varying, and often of serious dimensions.The exposition of these stresses and abuses, particularly dynamic stressing, corrosion, etc., all of which seriously affect the safety and economical life of the ropes, is often enough to frighten most practising mine staffs, who are aware that before the requirements of economic operation stands the still more important question of safety in mining.

Jan 1, 1947

By Blair J. R

A Train Performance Calculator (TPC) is an essential tool in railway operations, as a means of acquiring quickly a precise measure of the performance of the system. Traditionally the TPC was used in the form of program for a large computer. By employing an efficient integration algorithm and tailoring the program to suit the computer system it is shown that it is possible to devise a TPC for a mini computer. The resulting low running costs and flexibility of operation makes this a useful design tool. This TPC was developed to study problems associated with a single track railway operation. It was applied specifically to study the railway operated by the Mt. Newman Mining Co. Limited in the Pilbara region of W.A. to transport iron ore from the mine to the port. The TPC was used to calculate the effects of changes to locomotive power, to train size, to the track and to the amount of traffic. Its accuracy was checked by comparing its performance with that of the actual trains.

Jan 1, 1977

By M Csar

The Nicolsons Find gold project is located 35 km southwest of Halls Creek in the east Kimberley. It was discovered in the late 1980s by John Nicolson and Stuart Skoglund, when high grade gold mineralisation within outcropping gossanous quartz reefs was found. The area has produced a modest 28 150 ounces of gold over two brief mining periods in 1996 and 2002 - 2003. Indicated and inferred resources as of September 2011 stand at 1 384 000 t at 5.58 g/t Au for 248 500 ounces of gold.The project is situated within the Halls Creek Orogen. Principal host units are metasediments and volcaniclastic sediments of the Koongie Park Formation. Minor mafic units are also recognised. Immediately east of these units, emplacement of the loadstone granite is believed to have provided the structural setting for the later gold mineralising event.Mineralisation is hosted within a broad, brittle-ductile arcuate shear zone about the western contact of the Loadstone granite. In the Nicolsons Find area, the shear zone strikes north-northeast and within the shear zone, gold is hosted in a series of narrow, quartz rich veins up to 200 m in strike length, plunging moderately to the north-northeast. To date, mineralisation has been drilled to a depth of 360 m below the surface. The veins are stepped or en-echelon in nature with low gold values towards the quartz vein limits where compression is inferred and higher grades present in the dilational body of the quartz veins. Gold is fine grained and can be present with or without associated sulfides. Sulfides are generally minor and consist mainly of arsenopyrite with traces of chalcopyrite, pyrite and sphalerite. Where present, sulfides are generally indicative of higher gold values.CITATION:Csar, M, 2012. NicolsonÆs Find gold project, East Kimberley, Western Australia, in Proceedings Narrow Vein Mining 2012 , pp 31-36 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 26, 2012

Exploration for uranium in Australia has so far discovered reserves equal to 17.5% of the Western World's. The Australian uranium industry, when fully developed, will be one of the largest producers and possibly the largest exporter in the world. The world's nuclear industry is young, rapidly developing in size and technology and is subject to more social, political and regulatory controls than any other industry. This paper considers the probable development of Australia's uranium industry against a background of normal commercial parameters together with other factors which are peculiar to the nuclear industry. As the theme of this conference is "Australia's role in the World Mineral Indus- try" this paper concentrates on the commercial and practical aspects associated with the development of Australia's uranium resources in a world context.

Jan 1, 1979

By M Suzuki

Although several models for the surface tension of molten oxide slag have been proposed, suitably accurate predictions of this property are not yet possible. The surface tension, or surface excess free energy, of molten oxides is largely determined by the ionic coordination induced by surface relaxation. However, the associated mechanism of surface structural relaxation for molten oxide mixtures such as slag is complex and not yet fully understood. To allow a better evaluation of surface relaxation characteristics, the present work analysed the ionic coordination associated with the surface-relaxed states of several oxide mixtures. This work especially focused on calcium aluminate slags because these materials exhibit complex relationships between composition and surface tension. The effects of incorporating low concentrations of SiO2 as a surface active component on the surface ionic coordination were also examined. X-ray absorption techniques were used to assess oxygen and cationic elements in glassy samples after surface relaxation treatments, and molecular dynamics simulations based on a polarisable ion model of molten slag with vacuum/melt interfaces were also performed. The X-ray absorption techniques provided data related to electron yields (which are primarily associated with surface features) and fluorescence yields (which evaluate the bulk material). Thus, the ionic coordination characteristics of both regions were investigated. The results of molecular dynamics calculations allowed statistical analysis of the distributions of Al- or Sicentred polymorphs as well as the bond angles between cations and oxygen anions in the vacuumexposed and bulk regions in the equilibrated melt. The results indicated that bridging oxygen ions were preferentially distributed in the relaxed surface region rather than non-bridging oxygens. These bridging oxygen ions represented vertex connections between AlO4 or SiO4 tetrahedra. In the case of the calcium aluminate slags, the addition of one Ca2+ ion as charge compensation for two Al3+ ions was found to be necessary to form two AlO4 tetrahedra. This specific feature of surface ionic coordination could be responsible for the complex trends observed in surface tension data. The incorporation of low concentrations of SiO2 reduced the proportion of tetrahedrally-coordinated Al ions such that higher coordination states become dominant in the bulk of the material, whereas AlO4 tetrahedra were preferentially distributed in the surface region. SiO4 tetrahedra were the preferred Si-centred polymorph and were likely connected to one another to form bridging oxygen ions at the surface. On the basis of these results, a model to predict slag surface tension was proposed, and the energy of the formation of the ionic clusters resulting from surface relaxation was taken into account.

Aug 21, 2024

By T Kitajima, T Kawaguchi, T Nakamura

Carbothermic reduction of iron oxide is an attractive mechanism to produce metallic iron, since it can directly utilise coal as both reductant and fuel. To improve energy efficiency and productivity of the metallic iron production based on this mechanism, the combustion bed process packed with the composites of iron oxide and coal powder was experimentally evaluated. The process has a potential of high heat efficiency since it can automatically utilise the heat of reduced materials as that necessary to the subsequent reduction of the composite by a large heat exchange rate between the packed particles and gas flowed across the bed. However, it is hard to perfectly prevent the reoxidation of formed metallic iron in the bed. The present paper reports the effect of coal content, pellet size and so forth on the reduction/metallisation degrees of the samples after the reduction experiment. It also discusses the effect of pretreatment of the composite pellets using CaO bearing materials to suppress the reoxidation of formed metallic iron in the bed.

Jan 1, 2000

By P Pelletier, J Tessier, C Duchesne

This paper summarises research into the study of the control of flotation processes based on froth images. A review of the froth flotation operation background and the relevance and role of the froth phase are presented. The use of numerical image analysis techniques for the extraction of significant patterns from industrial flotation froths is discussed. First, the froth was analysed by the use of the multivariate image analysis (MIA) method to extract the spectral variation contained in a RBG image. The partial least squares (PLS) method was applied to develop an empirical model for the prediction of froth grade. The results of this application are illustrated using an industrial case study. Second, the froth was also analysed by grey-level co-occurrence matrix (GLCM) and wavelet transform analysis (WTA) to extract features related more to morphological aspects. Since there is useful information hidden in froth texture, these methods are used as texture descriptor to classify different types of froths. They also provide qualitative information on the changes in the visual appearance of the froth. The pros and the cons of those methods are highlighted. Third, a control strategy based on a froth structure indicator was developed and implemented on an industrial zinc flotation circuit. The feedback controller uses the reagent flow-rate in order to maintain the froth structure at its set point. Process improvements obtained from the implemented control strategy are highlighted. Finally, the feasibility of implementing a hybrid control strategy consisting in a froth structure supervision controller based on the froth concentrate grade estimated by MIA and recovery inferred by image analysis is discussed.

Jan 1, 2005

In South African gold mines, the types of material requiring transportation to the stoping areas include timber packs, explosives, hydraulic rock props, scrapers, scraper winches, pipes, pumps and backfill material (in areas where backfill is being used). Currently timber packs are broken down to their basic components (log and brick) and are transported into the stope by means of either monowinches or a combination of monowinch and scraper winch. Other materials, such as explosives, hydraulic rock props, scrapers, scraper winches, pipes, pumps and backfill material must be transported by other means, usually by hand or, in the case of heavier items, by chain blocks. With the drive to increase stope advance rates and the rise in the number of miners with HIV/AIDS, there is a need in the South African gold mining industry for an improved material handling system. To meet future requirements, material handling systems should assist miners to transport materials quickly and efficiently. Furthermore, it must be financially viable and economically competitive with current material handling systems. This paper looks at the in-stope material handling efficiency of current monowinch systems and provides solutions to improve efficiency. In addition, the use of in-stope monorails are reviewed and the possible scenarios that will substantiate the use of monorail systems are discussed.

Jan 1, 2003

By Ranklin W. J, Swinbourne D. R

Lead blast furnace slags contain typically 10 - 20 mass per cent Zn. The zinc can be recovered by slag fuming, in which a powdered coal/air mixture is injected into a molten slag bath. Volatilised zinc is recovered as zinc oxide from the gas and processed hydrometallurgically to produce zinc metal. The ISASMELT continuous lead smelting process in operation at Mt Isa produces a slag containing about 12 per cent Zn which is currently granulated and stockpiled. This slag could flow to a further bath-smelting reactor for continuous zinc fuming. Rather than collecting the zinc as fume from such a process, one option would be to recover it using a lead splash condenser. The success of this operation would depend on the composition of the gas produced, in particular the concentrations of gases capable of reoxidising zinc vapour, viz, carbon dioxide and water vapour. The aim of this investigation was to determine the smelting conditions for a bath-smelting process such as ISASMELT or SIROSMELT which would produce a gas similar in composition to that from an Imperial Smelting Furnace by thermodynamic modelling of the process using the CSIRO Thermochemistry System. It was found that such a gas could be produced if coal injection and oxygen enrichment of the combustion air to at least 40 per cent 02 were used. However, the off-take gases must be conditioned by addition of methane to reduce the water vapour content to acceptable levels. An addition rate of ten per cent of the off-gas flowrate was found to be adequate. Addition of methane to the off-gas had the added advantage of cooling the gas from the bath temperature to a temperature suitable for normal lead splash condenser operation.

Jan 1, 1993

Mining companies in order to compete and succeed in being viable business propositions must look to the future and select mining methods which guarantee improved efficiency and productivity as well as lower costs.A mining company in adopting a method of mining must now select the equipment most compatible. To some mines compatible equipment may mean the use of drilling jumbos to replace hand held rock drills or the use of load haul dump units to replace scrapers. To other more mechanized mines compatible equipment may mean the use of raise borers and road heading machines. The right decision will be where equipment compliments method in such a way that the working environment is improved, productivity is maximized, cost if reduced and all profit opportunities are optimized. An example of such is where the use of improved mining techniques in underground operations may see cut off grades reduced. By selectively mining these lower grade orebodies, smaller operation's ore reserves improve and the capacity for continued growth is enhanced.

Jan 1, 1990