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By Hiddlestone D. C

Effective exploration, testing and analysis is essential for good process design and optimisation of coal preparation plants. Coal processing relies on the sizing and washability characteristics of the particular coal to define the most cost effective design to meet the market requirements. Flowsheet development and equipment selection is dependent on the natural quality characteristics of the coal, its physical properties and the value of the final product in its market. The methodology of process selection and the key elements in design are discussed. Coal is consumed in two general markets: ò steaming coal - both domestic and export, and ò metallurgical coal. This paper discusses the typical economic analysis required to evaluate the potential for, and cost benefit of, providing the flexibility to switch coals between markets. A case study illustrates the methodology of process selection in a typical high value metallurgical coal.

Jan 1, 1997

By La Brooy S R, Fenton K

A low grade copper flotation tailing from Telfer containing 1.2% Cu as chalcocite and cuprite and 5 gt-t Au was leached with ammonia, cyanide and ammonia-cyanide mixtures to extract copper and/or gold. Direct cyanidation extracted both copper and gold but consumed about 30 kgt 1 NaCN. Pre-leaching the tailing with an aerated ammonia solution containing 28 kgt 1NH3 and 17 kgtl(NHa)2S0a at pH 10 readily extracted up to 95% Cu in about 6 hours under optimum conditions. However pH and total ammonia concentration were critical factors. Subsequent cyanidation ex- tracted 80% Au using 6 kgt NNaCN. Ammonia-cyanide mixtures werefound to selectively leach gold over copper depending on the concentration and relative proportion of NH3 and CN. The best composition for leaching up to 80% Au from Teller tailing was 1.6 kgt t NaCN and 1.1 kgf 1 NH3 in the presence of 0.3 kgt t Cue+. Such a mixture left only 50 mgL-1Cu in the final solution after precipitation of some of the initially dissolved copper.

Jan 1, 1991

The problem of instantaneous outbursts remains unsolved after over a century of events and the investigation of the mechanism of the phenomenon and means of treating it. Outbursts have occurred of up to 5,000 tonnes with perhaps up to 500,000 m3 of accompanying gas, either methane (CH4) or carbon dioxide (C02) or mixtures. The low density of CH4 and the high density of CO2 give particular problems. Australia with both gases has experienced outbursts for 85 years with fatalities as recent as 1978. The Bulli Seam of the Illawarra area of the Sydney Basin is affected and outbursts with both CH4 and CO2 occur. The Northern and Central Bowen Basin also experiences outbursts with both gases. Proneness of affected mines is related to the high rank of the'coal and the proneness of the seams-is localised according to depth, gassiness, structure and development geometry. Proneness may be reduced by appropriate choice of mining methods. In addition to outbursting mines other mines have symptomatic phenomena. Traditional preventive methods have been used and control by induce- ment has been practised. A method of local prediction for widespread use has not been achieved although locally successful prediction 1Superintendent Rock Mechanics and Strata Control, The Broken Hill Proprietary Company Limited, Steel Division Collieries, Wollongong, N_RW

Jan 1, 1980

Revised throughput rates, as a result of current mining methods and tight controls on mine dilution, have dictated a change in metallurgical philosophy at Renison Limited. Emphasis on throughput capacity increases has altered to a reduction in circuit complexity and operating costs. Extensive surveys of the gravity and cassiterite flotation circuits led to several plant modifications between August 1989 and March 1990. The coarse and fine gravity retreatment roughing tables were by-passed, the coarse gravity retreatment roughing tables were re-commissioned, the cassiterite flotation rougher capacity expanded and the gravity regrind cyclones re-configured.

Jan 1, 1991

By Kavetsky A, Scott A

As well as breaking and moving rock, blast energy sets up a seismic wave in the ground which can cause significant damage to rock structures and buildings and disturbance to human occupants. This seismic ground vibration is potentially most damaging when its dominant frequency coincides with the resonant frequency of a structure, leading to high amplification factors between the input ground vibration and the resulting structural response. This paper outlines methods of identifying the resonant frequency of structures. It also describes a practical numerical method for the modification of blast designs to reduce the ground vibration energy in critical frequency ranges. The method is illustrated with two recent case studies.

Jan 1, 1990

By Gray N. B

The need to improve existing metallurgical processes and to develop new processes to meet the economic challenges that lie ahead requires the application of the tools of process analysis viz. mathematical models, physical models, pilot plants, laboratory measurements and plant tests. Examples of the application of these techniques to processes are described in this paper. Several of these techniques, combined with basic knowledge, are necessary to make improvements and for existing processes this always involves plant measurements. Also because metallurgical processes include extraction, refining, alloying, casting, mechanical working and heat treatment, an interdisciplinary approach to research and development is essential. This paper argues that metallurgical engineering is a discipline that is uniquely able to encompass the broad spectrum of chemical- and physical-metallurgy processes and is therefore essential to the health of the metallurgical industry.Regrettably many metallurgical engineering departments are not offering courses on process analysis, control, optimization, etc so necessary to meet modern industrial challenges.

Jan 1, 1985

Longwall mining in Australia is approaching maturity. Longwall production from 'state of the art' Australian longwall mines now rivals similar US based longwall operations. Regrettably however, Australian gate road development rates in general fall short of the required development to longwall production ratios that are required to sustain annual longwall production capabilities. By contrast, most US based longwall mines achieve the required development to longwall production ratios to sustain their longwalls. This is despite many having to drive three heading longwall panel gate headings to meet regulatory requirements.

Jan 1, 1998

By Hendrix J. L, Nelson J. H

A model based on non-steady state has been developed for dissolution and diffusion in porous ore particles. Results from the particular model have been incorporated, as a rate term, into a global, heap-scale model based on a plug flow reactor at unsteady state. The global model can be used to consider leaching by aqueous-phase reagents in equilibrium with a gas- phase component, such as oxygen gas, as well as strictly aqueous-phase reagents, such as cyanide. The flexibility of the model even allows predic- tion of the outcomes of using reagent sideflow injection in large heaps. Data from column leaching tests are compared to the model, and their relationship is discussed.

Jan 1, 1991

At the Highway gold deposit, 37 kilometres south of Charters Towers, gold mineralisation occurs in several stratiform layers and is enriched near the surface by lateritic weathering. The host rocks of the mineralisation are ferruginous and baritic, intensely sericitised, kaolinised and silicified rhyolitic tuffs and pyroclastics of the Cambrian-Ordovician Mount Windsor Volcanics. The geology of the deposit is illustrated in Figures 1 and 2.Forty-six reverse circulation percussion drill holes were completed by North-Queensland Resources N.L. for a total of 2,093 metres of drilling to further outline and test the open pit resource. The drilling indicated a resource of 171,000 tonnes averaging 4.4 grams per tonne gold and 5.0 grams per tonne silver.A shallow initial pit, approximately 30 metres deep, has been designed to mine the high grade upper portion of the western stratiform layer and part of the eastern layer. This initial pit is designed to mine 45,400 tonnes of western mineralisation at an average grade of 7.84 grams per tonne gold and 22,200 tonnes of eastern mineralisation at an average grade of 1.42 grams per tonne gold. Waste is estimated at 110,900 tonnes.

Jan 1, 1986

By Erceg MM

The Waft River gold deposit is hosted by low grade metasediments which have been intruded by a dacite/andesite porphyry complex. Wafi River is classified as a high sulphur, epithermal type gold deposit having: a high sulphur content, a close association with calc-alkalic igneous rocks, zoned advanced argillic and argillic alteration, and enargite group minerals. Gold occurs as minute inclusions in pyrite and pyrrhotite within intermediate dickite/kaohnite - interlayered illitic clay alteration zones. Central leached silicic, alunite and pyrophyllite zones and peripheral chloritic zones are low in gold. The gold mineralisation at Wafi is interpreted to have been predominantly caused by mixing of hot upwelling acidic magmatic mineralised fluids with cool, neutral meteoric/hydrothermal fluids within permeable sediments. Locallised high grade breccia zones are encountered within the porphyry. An initial resource in excess of I million ounces Au has been defined.

Jan 1, 1990

The Macquarie Dictionary defines `information' as: knowledge communicated or received concerning some fact or circumstance; (in communicating theory): a quantitative measure of the contents of a message. For mining companies investing in data capture and information processing technology for operations management is a key issue. Beyond producing performance related information that employees can relate to it is being able to deliver that information into the workplace when it is required, to the employees that can utilise it. To be effective the data needs to be received and understood as `information'. The technology is now available and proven to enable `information' to be delivered into the mining workplace adding value to the activities performed by mine employees. The application of computers and information technology in the mining industry has typically been limited to the resource definition and planning stages, accounting and administration and the process plants that treat the ores and minerals. The mining extraction processes that consume expenditure and determine output in a mining operation occur in an environment dominated by unpredictable events and variable conditions. The mining operation has long been regarded as an inexact science conducted in unpredictable circumstances with many independent variables affecting the output and resultant cost of production. Financial accountants keep track of expenditure and management accountants analyse the cost of production usually on a weekly or monthly basis but all this effort can't affect the outcome, that was determined by the real time events and variations of circumstances over a week ago. Such reporting and analysis can result in conclusions being drawn about what improvements can be made and how you might do better next time, but generally the data is not detailed enough, is inaccurate or misrepresents the real issues. The capital investment required for any mining operation is substantial and comparable to other industries such as manufacturing. The performance and utilisation of manufacturing plants is usually closely monitored down to the lowest level of detail. Many modern plants are controlled and optimised using programmable intelligent devices and monitors display real time performance to the operators and prompt them to make informed decisions to maximise production and minimise wastage. Technology suitable for the mining industry is now widely available and has proven to be a reliable and powerful tool for the optimisation of mining operations. This paper focuses on the latest information technology developed by Modular Mining Systems that has been implemented in mining operations worldwide. The benefits reported by the mining companies utilising real time information technology over the past 15 years have generally related to optimisation of truck fleet allocation and material blending. Some mining operations have reported improvements in equipment utilisation of greater than 20 per cent. With the development of real time graphical display screens in the operators cabins the benefits of information delivery can be harnessed to make employees more effective in the workplace.

Jan 1, 1995

In Mount Isa voltage and frequency fluctuations caused. by haulage shaft operation gave considerable difficulties with the initial application of Atomic Absorption Spectro-photometry.The methods used to stabilise the various units ' have been described.- Some other difficulties and the means used to eliminate or reduce them together with a-modified burner design are also discussed.

Jan 1, 1963

The evolution of Hall process alumina reduction technology is des- cribed with particular attention to the pot lines. Future directions of tech- nological change are considered. It is predicted that the Hall process will continue to be the avenue for aluminium production for some time to come.

Jan 1, 1982

By Gilbert DJ, Lemon NM

A case history of a two year study of low grade ores in the Middleback Range area with the objective of defining possible areas of interest from a combination of geological- petrological-metallurgical criteria. Covering the general geology of the area and ore types; the results of metallurgical testwork and the pattern of evolution of these tests; the petrological explanation of the results of the testwork; the culmination of the work in the selection of areas of best potential for more intensive work. Jaspilites consisting of magnetite, hematite and limonite with quartz and silicate-carbonate-sulphide minerals are hosts to high grade iron mineralisation but also constitute a large low grade iron Reserve.

Jan 1, 1975

By Lawson F

A rotating disc geometry has been used to provide a uniformly accessible surface for a kinetic study of the cementation of the metals cadmium, lead and silver from dilute aqueous solutions. This work is an extension of studies carried out on the Cu/Zn and Cu/Fe systems for which the rection rate was found to be completely solution-phase mass-transfer controlled. When the amount of material deposited was greater than 0.2 to 0.4 mg/cm2 there was an apparent enhancement in e which is attributed to the formation of a roughened deposit. This same phenomeon was obseived in the Cu/Zn Cu/Fe systems. Again, the rate of reaction of each system investigated was found to be solution-phase mass ,..~sfer controlled.

Jan 1, 1970

By Johnson N. W, Munro P. D, Pease J. D

The Lead/Zinc Concentrator of Mount Isa Mines Limited processes complex fine grained ore from the Isa and Hilton silver-lead-zinc orebodies, producing lead concentrate, zinc concentrate and (until 1996) a low-grade middlings (LGM or bulk) conc

Jan 1, 1997

The Ocean Drilling Program is the largest international geoscience project in the world, and the state-of-the-art drill ship, the JOIDES Resolution, is permanently at sea. Each year there are six scientific cruises (Legs) which each last approximately two months. These legs are designed by geoscientists from the 19 countries that subscribe to ODP. Australia and Canada share ODP membership under the banner of the AUSCAN Consortium. The Australian Secretariat of the ODP is housed at the Department of Earth Sciences at James Cook University, along with the AUSCAN Consortium office. The Canadian Secretariat is presently based at the University of Toronto. Both secretariats have major research interests in the ore deposits, both ancient and modem, and so there is currently a major drive by the AUSCAN ODP Consortium to make available data and technological information to the minerals industry. This type of information includes data from drilling hydrothermal sites such as the hydrothermally active TAG black smoker complex on the Mid-Atlantic Ridge, drilled during Leg 158, and the Middle Valley sulphide deposit, on the northern Juan de Fuca Ridge, which was drilled during Leg 139.

Jan 1, 1996

By D Obeng, D Alexander

Over the past five years, commodity prices have been high and the focus of many plants has been æthe more metal the better, at whatever costÆ. In the recent economic crisis, the focus has shifted more to reducing the cost of production and operating at higher efficiency. Since 2002, JKTech has partnered with the Century mine in north-west Queensland to transfer technology and understanding through the good, bad and ugly economic environments, using methodology and techniques arising from research at the Julius Kruttschnitt Mineral Research Centre (JKMRC) and other research institutions around the world as part of the AMIRA International P9 Project. The JKTech studies were concentrated around the primary zinc circuit. During this period, Century expanded the primary zinc regrind capacity, installed additional scavenging capacity, installed and commissioned a Jameson cell for concentrate cleaning in the carbon preflotation circuit, and installed additional primary grinding capacity. Flotation circuit models were developed for each of the survey campaigns and enabled opportunities for further improvement to be identified, implemented and tested in the subsequent campaign.

Jan 1, 2009

By Armstrong M, Kleingeld W. J

Current low prices for many metals mean that deposits have to be mined at high cut-offs (relative to their mean grade), which means that only a small percentage of mining blocks are above cut-off. Worse, at such high cut-offs, the blocks above cut-off are usually not grouped into convenient clumps for mining; they tend to be split into small isolated patches that are difficult to reach and hence expensive to extract. Companies wishing to acquire mineral properties have to be able to work out quickly what percentage of blocks are above cut-off and what can effectively be mined given the mining method envisaged. Moreover they need this information within a relatively short-time. The work presented here relates to typical South African gold mines (ie tabular orebodies) but the long-term objective is to develop tools for quantifying the impact of reserve breakup at high cut-offs for a wide range of underground mines including those that are not tabular. The mining method and the sampling procedure determine whether ore blocks can effectively be located and extracted economically. This project studied the impact of these two factors on the recoverable reserves for Witwatersrand gold mines. In order to be repeatable, the tests were done on numerical models of the deposit obtained by geostatistical simulations. To ensure realism, the orebody model and the mining scenarios were based on a specific mine. The recoverable reserves (ore tonnage above cut-off, the corresponding metal quantity and the average grade) were calculated for a wide range of cut-offs for four mining scenarios, as well as for the base case of free selection: ò Scenario 1: Blocks are taken if their true grade is above cut-off and if they are accessible from a raiseline (no information effect, no marginal blocks). ò Scenario 2: In addition to the accessible pay blocks, adjoining marginal blocks are taken (no information effect, + marginal blocks). ò Scenario 3: Blocks are taken if their estimated grade is above cut-off and if they are accessible from a raiseline. Here the estimator is the average of the face samples (information effect, no marginal blocks): ò Scenario 4: Accessible pay blocks are taken if their estimated grade is above cut-off. Adjoining marginal blocksare also taken (information effect, + marginal blocks). ò Free selection: All blocks whose true grade is above cut-off are taken irrespective of their accessibility. The results can be presented in different ways, for example by plotting ore tonnage above cut-off versus cut-off grade, or metal tonnage above cut-off versus cut-off grade etc. As expected, this shows the hierarchy between the five scenarios from the free selection base case to scenario No 2 (true accumulations, pay +

Jan 1, 1995

By K Marler

The Water Act 2000 includes provisions to manage the take of overland flow water. Overland flow water is water that runs across the land after rainfall either before it enters a watercourse, after it leaves a watercourse as floodwater, or after it rises to the surface naturally from underground. To ensure adequate environmental flows and long-term security for water users, it is necessary to balance the amount of water taken as overland flow water and the amount left to flow into watercourses. A water resource plan made under the Water Act 2000 establishes the basis for the sustainable management of this type of water. Of the water resource plans that have been prepared for Queensland catchments, six include provisions to manage the take of overland flow water. This paper discusses some of the common features of these plans and the management approaches adopted. The paper identifies and explains key aspects of the Water Act 2000 framework for managing the take of overland flow water by the mining industry. In particular it explains key concepts of this framework, such as the ability to take overland flow water using existing works, uses of overland flow water that a water resource plan permits, situations where a specific entitlement under the Water Act 2000 is required, and the means for controlling works that take overland flow water. Future initiatives for the regulation and management of overland flow water are then identified and particular challenges for the mining industry associated with using overland flow water highlighted.

Jan 1, 2006