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By D J. Cronin

Alcoa World Alumina AustraliaÆs Huntly and Willowdale bauxite mines are located in the Darling Range of South Western Australia, which places their operations within PerthÆs surface water supply catchments. These catchments supply Perth with its highest quality drinking water. With the decreasing rainfall trend of recent years catchment yields to water supply reservoirs have reduced to such an extent that water use restrictions were necessary in Perth for 2001, 2002 and 2003. Protection of catchment water quality and water use conservation are crucial issues for AlcoaÆs operations within the Darling Range. Alcoa has been conducting bauxite mining activities in water supply catchments since the mid-1960s. During that time Alcoa has worked closely with the relevant State Government water and environmental agencies to ensure that its operations do not adversely impact catchment water yield and water quality. Monitoring and research have shown that Alcoa has the necessary environmental management systems in place to ensure it can continue to operate in a sustainable manner within water supply catchments. AlcoaÆs mines reduced the volume of water taken from public water supply catchments by 24 per cent in 2002, compared with 2000. This success has had an added benefit; Alcoa does not need to develop a new water source for its Huntly Mine. The conservation measures implemented to reduce water use include: increasing water recycling, using chemical additives for haul road dust suppression, conducting water audits, reducing water demand, monitoring water use, promoting water use targets and training staff in water conservation.

Jan 1, 2003

By Brennan D. J

The trend worldwide is for increasingly stringent control of sulphur dioxide emissions to the environment. It is therefore likely that Australian industry will be placed under increased pressure to restrict such emissions, and this will have implications for Australian smelters of mineral sulphide ores. Traditional outlets for sulphur dioxide emissions have been in sulphuric acid manufacture, but Australian demand for sulphuric acid has declined markedly in recent years. This paper examines the balance of supply and demand for sulphur and related products in Australia, the shifts occurring in that balance and the underlying causes of those trends.

Jan 1, 1994

By A Olshina, C Willman, D Moore

GeoScience Victoria has completed quantitative assessments of undiscovered gold endowment in the northern parts of the Bendigo and Stawell Zones. The under cover area in the Bendigo Zone (10 000 km2) is likely to contain approximately 1000 t and at least 290 t of gold in undiscovered mesozonal orogenic gold deposits. For the under cover area in the Stawell Zone (30 000 km2), the estimates are approximately 1200 t and at least 200 t of undiscovered mesozonal orogenic gold. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By Williams P, Hender A

The 1980s witnessed a major revolution in the application of airborne geophysics to mineral exploration. The now commonplace term `high resolution aeromagnetics' (HRA) evolved from advances in survey specifications, instrumentation, data processing and imaging techniques which greatly improved the quality and geological information content of the final maps. Although initially HRA was successfully applied in `hard rock' basement terrains, eg the Archaean Yilgarn Craton of Western Australia, the technique along with the radiometric and electromagnetic techniques is now gaining wide acceptance in all geological terrains including inaccessible sedimentary rock dominated mountain belts such as New Guinea for mineral and petroleum exploration. It is also being used in more and more diverse roles away from exploration, such as environmental monitoring. The main reason for this acceptance is of course the very cost-effective surface and sub-surface mapping capabilities of the various airborne techniques. Although the three main techniques (magnetic, radiometric and electromagnetic) have been in use for some time, they are continuously being improved. Recent developments include: ò better navigational positioning using real-time GPS systems (Geographic Positioning Systems) such as Picodas Navigation Systen (PNAV); ò the use of magnetic gradiometer systems; ò improved sensitivity and sampling rate of magnetometers; ò increased use of ultra detailed low level (

Jan 1, 1996

By Brien RT, O&apos

The work reported in this paper extends,-bhsb on the "Heat Hardening of Artificial Magnetite ;Pellets"., which was described at the- International Symposium on Agglomeration ;-sponsored by the American Institute. of Mining, Metallurgical and Petroleum Engineers at Philadelphia; U.S.A. in April, 1961. Whereas- that work was of a.,more basic nature, -serving to illustrate the suitability of artificialòmagnetites with various.admixtures, to the application of heat hardened pellets, on: this occasion the aim-is to illustrate the procedures-which were used-to- establish the dimensions of commercialòrecuperativ strands for Australian raw materials,The nature of the pellet feed, i.e. relatively uniform :spheres of4 3/8 in. - 7/16. in. diameter, makes it possible to use small scale static pots for test work. By the use of a closed system and the measurement of suctions, gas f lows, and temperatures through beds, the speed and heat requirements of the various stages of heat hardening can be measured, so: that for a specified quality of product estimates can be made of the broad design characteristics of a moving grate system. In practice of course it is .usual to correlate the data from this type-of :experimental 'apparatus with . existing production units upon which good operating data, in the statistical sense, are available.

Jan 1, 1963

By Y S. Zhang

Natural phenomena and human engineering construction activities had great influence on the geosciences space. Natural disasters, particularly mine disaster and other geological disasters happened frequently, which brought great losses both in people’s lives and economics, therefore, to explore the essential causes and mechanisms of disaster by some useful approaches is the most important step in mine disaster prevention. In a variety of methods, building an aground-underground seamlessly integrated model, and then analysing the formation and development mechanism of mining disaster based on this model is a useful way. In this paper, we studied an aground-underground seamlessly Integrated modelling method, and correspondingly given an aground-underground seamlessly integrated 3D spatial model, CSG+CD-TIN+GTP-TTS, by which we can carry out analysis of surface subsidence and underground laneway distortion efficiently, finally preliminary applications verified the effectiveness of this method.

Nov 22, 2011

By L Köresaar, J Moilanen

With lower and increasingly variable Fe grades in iron ore resources, the monitoring of Si, Al, Mg and other light elements to meet quality requirements is gaining importance in the iron ore beneficiation industry. The high cost per manual assay and associated manpower requirements often limit the frequency of shift composite samples and laboratory assays. Furthermore, the shift composite assays represent past performance of a plant but are not useful for immediate reactions to feed variations, detection of equipment malfunctions or process control. Automated online analysis of light elements radically reduces the cost per assay and provides repeatable, timely data for process analysis, control and optimisation.A light element online slurry analyser, based on laser-induced breakdown spectroscopy (LIBS) optical emission technique, will be presented. This paper discusses the analyser design for the iron ore industry and also reviews the performance of the analyser against the manual laboratory. Additionally operator safety, user friendliness and maintenance requirements are discussed.A case study will also be discussed in this paper. The sophisticated measurement technique has been implemented in an industrial automated analyser and sampling system to allow for slurry measurement for up to 12 sampling points. However, careful selection of the sampling points and implementation of the sampling system is required for smooth operation.CITATION:Köresaar, L, Timperi, J and Moilanen, J, 2015. Optimised process control in iron ore via online analysis of light elements, in Proceedings Iron Ore 2015, pp 511–518 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

Precious metal mineralization at the North Arm goldfield in SE Queensland occurs in the Triassic North Arm Volcanics, a sequence of andesite to rhyolite, pyroclastic and epi- clastic rocks deposited in a continental envir- onment. This unit displays a well-defined fracture system on Landsat imagery, including several arcuate structures which may represent former calderas. Two of the latter are associ- ated with zones of hydrothermal alteration, breccias and anomalous precious and volatile metal values. At the North Arm prospect, alter- ation is zoned from outer propylitic into exten- sive sericitic, although K-feldspar alteration is prevalent in the rhyolite. A zone of advanced argillic alteration is also present at Mt. Ninderry, SSE of North Arm. Alteration involves depletion of Na, Ca and Sr, and vari- able enrichment of S, As, Au, Ag, Hg and Mo. K and Rb are strongly enriched in K-feldspar altered zones. Precious metal mineralization occurs in veins, stockworks and hydrothermal breccia zones, and pervasive low grade Au-Ag dispersion is found throughout the sericitic and K-feldspar altered rocks. Veins and brec- cia interstices contain abundant quartz (common- ly banded), minor pyrite, calcite and sericite, with traces of silver grading to electrum, frei- bergite, naumannite, allargentum, marcasite, chalcopyrite and sphalerite. Mineralogical and geochemical characteristics are consistent with that found at volcanic-hosted epithermal precious metal deposits, particularly with the low-sulphur/adularia-sericite type.

Jan 1, 1987

By M Chiquito, R Castedo, P Segarra, L M. López, J A. Sanchidrián, J Navarro

The aim of this work is to assess the performance of different constructive solutions against explosions on the strength of masonry walls. The solutions tested, namely an external metal mesh, a glass fibre film on the external face of the wall and a basalt fibre film located on the inner face of the wall, have low to medium cost and are originally designed for other purposes, like seismic protection. Four cubic boxes 3 × 3 × 3 m were built using each of the solutions and typical masonry blocks. In the tests, a spherical plastic explosive initiated in the centre was placed at scaled distance of 2.9 m/kg1/3, so that moderate damage would be caused on the wall. In order to assess the performance of the explosive, pressure gauges were placed at the wall and at different distances from the explosion. Additionally, vibrations were monitored with seismographs in the far field and a high-speed camera was used to estimate the shock wave velocity during the tests. The resulting damage has been evaluated on 13 points of the external wall of each box using a rebound hammer. Damage maps have been drawn for each wall based on these measurements and damage has been assessed inside the box considering the fragments mass launched during the test. The use of external metal mess leads to a decrease of 34 per cent on damage of the external wall and 38 per cent reduction of spalling. The use of a film in the inner wall provides a strong reduction on spalling.CITATION:López, L M, Segarra, P, Castedo, R, Sanchidrián, J A, Navarro, J, Santos, A P and Chiquito, M, 2015. Performance of different constructive solutions against explosions in full-scale masonry walls, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 819–824 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

Many parameters are important when considering the performance of a concentrator. These include metallurgical performance, such as throughput, metal recovery and final concentrate grade and operating costs, such as power consumption, water usage, reagents and spare parts. In most operations the objective is to maximise metallurgical performance and minimise operating costs, ideally without a large investment in new capital items. A number of projects have been carried out at Newcrest MiningÆs Cadia Valley Operations (CVO) with the aim of improving metallurgical performance and minimising operating costs. This paper focuses on the installation of newly designed flotation mechanisms in various cells in the Cadia flotation circuit and describes the effect these changes had on performance and operating costs.

Jan 1, 2009

By M Kilburn, A Edenton, M Adam, A Dehghan-Manshadi, R Smyth, L Lu

The blast furnace is a counter current reactor. The counter current principle of the furnace makes it very efficient in transferring the heat and mass required to drive the reduction reactions inside the furnace. However, this does impose a stringent requirement on the permeability of burden material in the furnace. Lump ore is one of the key ferrous feeds used in the blast furnace ironmaking process, often accounting for ten to 20 per cent of the blast furnace ferrous burden. As the lump ore descends through the blast furnace, it is dried, heated and reduced by the ascending hot reducing gas. To ensure good furnace permeability, generation of fines from burden materials including lump ore due to mechanical, thermal and chemical processes needs to be minimised. Unlike sinter and pellets, lump ore is subject to thermal degradation. To assess this behaviour of lump, the ISO decrepitation test (ISO 8371, 2007) is often conducted, and the result is calculated as a decrepitation index (DI). However, the DI values obtained from the existing ISO decrepitation test vary considerably between test portions and between laboratories, which makes meaningful comparison very difficult. In order to identify the sources responsible for the unacceptable repeatability, the effect of various testing conditions, such as particle size, heating rate, sample preparation and loading method, on the mean DI value was studied. The mechanisms contributing to thermal degradation in the top of the blast furnace and during the standardised decrepitation test are also discussed.CITATION:Lu, L, Kilburn, M, Dehghan-Manshadi, A, Adam, M, Edenton, A and Smyth, R, 2013. Thermal degradation of lump ore in the top shaft of blast furnaces, in Proceedings Iron Ore 2013 , pp 421-426 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

Anodic stripping voltammetry is an analytical technique which has established some popularity for trace analysis of metals because of its sensitivity, selectivity and capability for simultaneous analysis of some elements. The technique can be readily adapted for field use because of its relative simplicity and low power requirements. This paper describes a relatively new instrument, the Portable Digital Voltammeter, developed by CSIRO, which utilises the glassy carbon electrode in a novel cell design and provides parts per billion (ug/L) sensitivity in an instrument which can be field operated. Ten elements, Zn, Cd, Tl, Pb, Cu, Sb, Bi, Hg, As and Au can be routinely analysed. Many of these elements are of interest to the mining industry, and to exploration geochemistry in particular. Case histories where the instrument has been successfully employed for stream and stream sediment analysis of Cu and Pb, for soil surveys of Cu and Au, and for Au in stream sediments and drill chips indicate there are advantages in having on-site data, during Exploration.

Jan 1, 1987

By McManus D

Situations where in-pit bench stripping methods are favourable are introduced. Examples from Peak Downs Mine are used as a guide to the range of methods available.A number of geological and geotechnical conditions adverse to successful in-pit bench stripping are described. In all cases bench, floor, and/or final lowwall instability can develop and compromise the economics of extraction.

Jan 1, 1992

By G Haywood

This paper presents the evolution of the planning, scheduling and mining practices at the Yilgarn Star underground. The paper will concentrate on the principals of æjust in timeÆ and the impact of such practices on mine planning and scheduling and subsequent development and production. The principals of æjust in timeÆ were developed to minimise the impact of creep and time dependent failure of the ground in the ore and hangingwall zones. These zones are characterised by altered schistose material with inherent weak rock strengths compounded, at depth, by the maximum principal stress of the virgin stress field approaching the UCS of the rock mass. Yilgarn Star underground has and continues to develop the æjust in timeÆ methodology to ensure the continued viability of the mine. The mine continues to use longhole open stoping mining methods to ensure high levels of productivity with minimal dilution and at an acceptable cost of production.

Jan 1, 2002

By C van Wyk, I Reeves, J Webber, G B. Gnoinski

The minerals industry has been given an opportunity to grow and continue to advance again in an environment where there is the potential to reap big rewards for efficiency improvements due to buoyant metal prices and the growing demand of markets in Asia. Improving efficiency may also provide a better return compared to risks of expansions and bringing new projects online due to limited human and financial capital.An opportunity for improvement presents itself in the area of mine-mill reconciliation, which entails the quantification of the variance between measurement points along the mining value chain. Reconciliation factors are calculated from the variance between respective sections within the mining sequence. These factors are commonly used as key performance indicators to provide a check on the performance of the operations. Over parts of the mining value chain, there is a fair understanding of the reconciliation between the Resource and Reserve estimates and the measured metallurgical plant inputs and product outputs through understanding of the mine-mill interface. The quality of reconciliation data gathered across the mine and plant is generally not well established due to practices employed in generating the data. The reconciliation variances are often a function of data accuracy and quality used in the comparison. In general, the sources and magnitude of measurement and sampling errors and their impact on reconciliation are not that well understood. Examples of the current practices of mass measurement, sampling, sample preparation, chemical analysis and quality assurance for broken ore and across the metallurgical process stream are considered. Guidelines are given for those reconciliation elements that are identified as requiring a high degree of confidence for Mineral Resource/Reserve and metal accounting reporting. These guidelines are presented and practices are demonstrated to improve mine to mill reconciliation and support increased resource to product efficiency and value.CITATION:Gnoinski, G B, van Wyk, C, Webber, J and Reeves, I, 2012. Guidelines and practical applications for continuous improvement in mine to mill reconciliation, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 309-316 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

Chlorination of organic matter by direct injection of chlorine gas or hypochlorite has been investigated metallurgically worldwide with little understanding of the basic chemistry of the passivation mechanisms in- volved. In this paper, chlorination of carbon is attributed to oxidation-reduc- tions, resulting in surface halogenation of graphitic or amorphous carbon. It is proposed that chlorine and carbon interact to form thin coatings of chioro-carbon complexes that block the adsorption of gold cyanide com- plexes, thus passivating the gold adsorption sites of carbonaceous matter. Analytical, spectrographic, microscopic and electron-optical methods have been applied to demonstrate the proposed mechanism of chlorine-carbon bonding, as well as to evaluate the advantages and limitations of chlorination in the pretreatment of refractory carbonaceous gold ores.

Jan 1, 1991

Mount Isa mine is the largest underground mine in Australia and is located 2,000 kilometres north-west of Brisbane. This mine has been in continuous operation since 1931 and in 1986/87 the silver/lead/zinc stream achieved the peak annual mining rate of 4.7 million tonnes. At present about fifteen different steeply dipping stratiform orebodies are being mined to maintain an annual production rate of around 3.0 million tonnes. Out of these, only two orebodies (2 & 5) are amenable to sub level open stoping (SLOS) type bulk mining methods. This year only 150,000 tonnes are scheduled from pillars and remnant areas but in future, more sources will be required to meet the budget production targets.

Jan 1, 1990

By Wills BA, Barley RW

A brief description of viscosity measuring devices used in Dense Media Separation (DMS) plants is given, including a new On-line viscometer system. The various factors which affect suspension viscosity are identified. The effect of temperature variation on viscosity and viscosity measurement is examined in detail. Practical problems in using a modified Stormer viscometer for laboratory testwork are noted. Likely problems of continuous viscosity measurements are also discussed.

Jan 1, 1987

By C Li, S Wang, L Qiao

Jinchuan nickel mine is the largest nickel mine in China. Cut-and-fill mining method with high density cementing materials is used in the mine. The original mining design divided the mining operation into two steps. The first step stopped the mining rooms and the second step stopped the pillars. Because the two-step method made big trouble for finally mining pillars and strongly limited the mining speed and production, it was successfully changed to a continuous cut-and-fill method without pillars. However, the mining operation in the mine has been down to 800 m and the mining condition is getting worse and more complicated. Through systemetical field investigations and 3D FEM analysis, it is proved that the mining method without pillars is feasible for mining deeper orebodies in Jinchuan nickel mine.

Jan 1, 2000

In recent years, the. art of electric steelmaking has received a great deal of attention, and naturally, much controversy has existed from time to time regarding the relative merits of different practices and tywes of furnaces. Nevertheless, at the present time, the basic principles of the process are reasonably well established, and by far the greatest percentage of electric steel is a product of the basic lined, direct arc type furnace. Ferro alloy manufacture has demanded the development of furnaces having very different characteristics to those used for steel. Some special alloys, however, require conditions of manufacture which are more closely approached in the steel type furnace, and thus the latter has been adapted where necessary for the production of these alloys.One such alloy, low carbon ferro-manganese, is manufactured at Whyalla, South Australia, in a basic-lined, direct arc furnace, which is used alternatively for the production of alloy steels.BRIEF HISTORY OF THE ELECTRIC FURNACEThe principle of melting by electricity was first applied to the melting of iron in 1879 by William von Siemens, whose equipment consisted of a small crucible into which were introduced two carbon electrodes. Very little practical development took place in the next 20 years, although in 1890 a Frenchman named Heroult designed a direct arc furnace for the production of ferro alloys. At the beginning of the 20th century, several types of furnaces were patented for steel melting, the most important of these being the Heroult, using a direct arc, the...

Jan 1, 1951