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A thick sequence of alkaline intrusions and volcanic rocks underlies a Quaternary caldera on Liliir Island. The sequence is host to a still active sub-aerial hydrothermal system and associated epithermal gold mineralisation. Sub-horizontal alteration horizons exhibit progressively increasing chondrite norma-lised (La/Lu) en and (La/Sm) cn ratios from unaltered shoshonites, to the potassic alteration zone, to the argillic altera-tion zone to the advanced argillic alte-ration zone. The increasing fractionation of HEE, and especially of LHEE, up the alteration sequence is the result of de-creasing pH, temperature and alkalinity of the hydrothermal fluids with increa-sing alteration intensity. HRE3 were especially mobile in argillic and advanced argillic alteration units characterised by acid fluid conditions and large fluid volumes. Abundant Cl, S and CO2 within the hydrothermal fluids and thus abundant REE complexing agents and large fluid volumes favoured the mobility of REE during hydro-thermal alteration of the volcanic rocks and intrusions. Steam escape, mixing of the gases with groundwater and a change from a magmatic neutral chloride hydro-thermal system to a meteoric acid sulphate system was accompanied by liquid/vapour ratio changes, pronounced alkalinity, pH and temperature decreases, and fluid/rock ratio increases. This caused the mobili-sation, fractionation and deposition of PF.F.

Jan 1, 1990

Copper was first produced in Australia in 1844, at the Kapunda Mine in South Australia, and, by 18i>0, production exceeded 2,000 tons of copper a year. Output increased ,steadily, reaching a peak of 14,00Qo tons a year in 1867 and 1868, when the Burra Burra and Kapunda Mines in South Australia and the Peak Downs Moine at Clermont, Queensland, were at the height of their production. At this period, Australian copper formed a considerable percentage of the world's supply, its output equalling, for a short time, that of the United States. Production declined to between 3,000 and 4,000 tons a year after the closing of' these three mines between 18717 and 1879, and, at this stage, the Australian output came chiefly from the Wallatoo and Moonta mines in South Australia. About 19000, it began to rise again, with the extension of the railway to the copper fields of Chillagoe and Cloncurry, and, between 1905 and 1912, was at its greatest, with a maximum of 47,774 tons of copper in 1912. During this period, Australia contributed 4,7 per cent. of the world's annual production, and ranked among the six major copper-producing countries of the world (Table 1).

Jan 1, 1943

By M DellÆAmico, K Vining

The iron blast furnace is the most widely used and efficient producer of liquid iron; however, emissions from sintering and coking cause environmental pressure for the integrated steel works. The combustion of coke fines (breeze) during sintering contributes to greenhouse gases (GHG) (eg carbon dioxide) and is a source of SOx and NOx emissions. Coking capacity is also constrained by environmental concerns and economic factors, such as increased coke consumption, and short supply is leading to high prices. Improved coking practices, which result in reduced production of fines, are also contributing to the tight availability of breeze for sintering. This combination of factors presents an opportunity to consider alternatives to coke as a fuel for sintering. CSIRO Minerals has been investigating the use of wood biomass/char as a substitute for coke during sintering. Wood biomass, or char produced from it, is an attractive carbon source as carbon dioxide liberated during combustion can be sequestered back into growing biomass. It has great potential to reduce the emissions from integrated steelworks and improve their environmental acceptability. Harvested biomass/char is also a renewable and sustainable resource and can be integrated with good land management practices such as remediation of salinity affected land. Weeds, especially woody weeds, can also be used as a source of biomass for charcoal, and integrating char production with weed management can help address a pressing environmental issue in Australia. Previous reported preliminary testwork indicated that the use of Red Gum char as a replacement for coke resulted in a product sinter of comparable quality, improvements in productivity and significant reductions in SOx and NOx emissions. In the latest testwork, CSIRO has examined the properties of a range of potential charcoals, and has conducted a further series of granulation and small-scale sintering trials with them in simulated Japanese Steel Mill iron ore blends. Sinter fuels characterised and evaluated include industry sourced coke breeze, commercially available wood char and a charcoal from prickly acacia (acacia nilotica). Prickly acacia has been declared a noxious weed, is widespread in Australia, and is classified as a æWeed of National SignificanceÆ. The results presented in this paper support the notion that charcoal outperforms coke in many aspects of iron ore sintering and factoring in environmental considerations makes the switch to charcoal even more favourable.

Jan 1, 2005

By Fullagar P. K

In resource definition and mine development, major capital expenditures are committed on the basis of sparse information and even in production surprises such as bad ground are not uncommon. Drill holes constitute the principal source of information about the orebody and its environment and optimisation of drilling implies maximising the yield of useful information per dollar expended. Geophysical borehole logging provides new flexibility for optimising the drilling budget. Economic benefits can flow from geophysical logging at all stages of the mining cycle. The most commonly cited benefit is substitution of diamond delineation drilling with cheaper percussion or reverse circulation drilling in cases where geophysical logs can substitute for core. This approach can deliver an attractive direct saving in drilling costs (and time) if drill meterage is unchanged, or a potentially greater indirect benefit from better ore control if more holes are drilled within the original drilling budget. More ore contact intercepts per dollar can translate into lower dilution and enhanced ore recovery, thereby increasing revenue as well as reducing mining costs. Substitution of diamond drilling with percussion drilling is not always feasible. However, geophysical logging of diamond holes is often highly advantageous in its own right, both for geotechnical characterisation as well as ore delineation. Operational advantages of logging include data objectivity, speed of interpretation and reduced core handling and analysis costs. Geophysical logging assists mining engineers by providing a continuous measure of in situ rock strength, even over intervals with poor core recovery. The additional expense of geophysical logging in blast holes can be justified in terms of more accurate ore boundary delineation and rock strength evaluation. Precise ore boundary delineation permits refinement of charge placement, to minimise dilution and maximise recovery. Detailed knowledge of rock strength can enable optimisation of blast design. Rock strength can be evaluated in real-time via analysis of drill performance data recorded with measurement-while-drilling (MWD) technology. To successfully apply geophysical logging in mines, its technical, operational and economic viability must all be established. This entails verification of the existence of appropriate physical property contrasts, investigation of the best way to integrate the geophysical results with the mining method and an objective assessment of the value of the resulting mine performance benefit. Geophysical logging is already well established in many mining operations. The greatest impediments to its wider utilisation at mines are: lack of appreciation of geophysics by most mine geologists, engineers and managers; limited interpretational aids; and the necessity to re-enter completed drill holes. In this paper we endeavour to address these issues by informing mine geologists about potential applications of geophysics, by illustrating automated interpretation of geophysical logs and by highlighting the importance of emerging MWD and logging- while-drilling (LWD) technology.

Jan 1, 1997

By Bourgeois F

The population balance concept has provided a useful framework for the description of the operating behavior of the ball mill. This approach finds expression in the so-called selection breakage function model for batch and continuous mills. This model produces very good descriptions of the size distribution of the products from ball milling operations and the model is very useful for the description of batch and continuous mills and, when combined with models for classifiers and other unit operations, provides a solid basis for flowsheet simulation procedures. The breakage and selection function model is essentially descriptive and not predictive because the parameters in the model cannot as yet be related to the fundamental material properties of the material that is broken and to the fracture mechanics that govern the comminution of brittle particulate material during the rapid impact and compression events that occur with high frequency in a ball mill. The population balance approach smears over the individual processes and regards the ball mill as a continuum with breakage occurring continuously in time and space. New experimental techniques, particularly the adaptation of the Hopkinson bar as the ultrafast load cell (UFLC) to the problem of observing the extremely rapid impact fracture of particulate solids, have made it possible to make accurate and consistent measurements of particle strength, particle fracture energy and the single-impact breakage function. These quantitative measurements have been incorporated into a new conceptual model for the description of the ball mill. The model is based on identifying all events that give rise to particle breakage, and using the fundamental experimental data obtained on the UFLC and other single-particle fracture tests, the probabilities of these events can be independently determined. The distribution of impact energies that occur in the ball mill has been established by discrete element simulation of the media motion. The probabilistic description of the individual fracture events and the distribution of impact energies are combined to make a priori predictions of ball mill performance under a variety of operating conditions. The new model is used to calculate the selection and breakage functions for quartz in a small batch mill.

Jan 1, 1993

By Farrelly C. T

The Wiluna mining operations are centred near the township of Wiluna 750 kilometres north-east of Perth and 600 kilometres east of Geraldton.The Wiluna gold mines produced over two million ounces of gold, predominantly by roasting the refractory sulphide ores, before closing in 1947. In the period 1984 to 1992, 668 000 ounces of gold has been produced from free milling oxide ores and the retreatment of tailing. A plant capable of treating the refractory sulphide ores using the bacterial oxidation, Biox technique was commissioned in March, 1993.The Wiluna lode deposits are hosted by a sequence of very low grade metamorphosed mafic flows at the northern end of the Norseman-Wiluna greenstone belt. A strike slip fault system provided conduits for fluid migration; ore deposition occurred at favourable sites along the faults. Satellite mines at Gourdis and Wiluna South provide laterite and lode style oxide ores.The different styles of deposit and ore types at the Wiluna mining operations require a flexible approach to resource estimation and grade control practices.

Jan 1, 1993

By Galecki G

The investigations conducted in the High Pressure Lab at the University of Missouri-Rolla demonstrated the ability of high pressure waterjets to excavate coal and minerals, disintegrate materials and as well as to comminute coal and minerals. Additional progress in comminution can be achieved if the compressive crushing principle commonly used at present is changed to one where particles are fragmented by the tensile growth of preexisting internal flaws or cracks, under internal waterjet pressure. This idea was studied in a number of tests. It covers tests with different jets imposed on coal and rock samples during compressive load as well as without any loading.

Jan 1, 1993

The electrochemical dissolution of gold and other noble metals in hydrochloric acid using alternating current has been investigated. The experimental results show that this technique is efficient for dissolving pure noble metals and offers prospects for their extraction from wastes and poor ores.

Jan 1, 1992

With production at Olympic Dam scheduled to commence in June 1988, it has been necessary to install a complete underground ore handling system capable of removing two million tonnes of material annually from the mine. The system comprises mucking from stope drawpoints, truck haulage to underground storage, primary crushing, conveying and hoisting. On the surface, material is conveyed to stockpiles at the Metallurgical Plant. Mining of the numerous special excavations within the system was incorporated into the mine's ongoing development program prior to the underground construction phase. Utilisation of a decline from the surface enabled versatile construction equipment to operate at the underground sites as well as simplifying the transportation and delivery of construction Materials.

Jan 1, 1988

Diversification has characterised the mining industry in this country and globally in recent decades, and in Western Australia in particular. One of the most obvious aspects of diversification is technological change which continues at a rapid and sometimes bewildering pace. A function of technological advances is the increased capacity to further diversify the range of minerals which can be identified in economic concentrations and profitably extracted. This broadening of the total base of the industry has a synergistic effect on its further development by extending its geographical spread and increasing scope for decentralised infrastructure. Another aspect of diversification is the corporate thrust towards establishing overseas mining bases for a variety of reasons. Off-shore (sea bed) mining is a further manifestation of increasing diversity, although very much in its infancy.

Jan 1, 1996

A Study on Process Mineralogy and Mineral Processing of Complex Carbon-Bearing Cu-Pb-Co-Ni Multi-Metal Sulfide Ore by Bulk Flotation

Sep 13, 2010

In late 1987 it was recognised that column flotation might have potential for improving the grade of the zinc concentrate produced at Pasminco's South Mine in Broken Hill. Intermittent test work was carried out during 1988 using a 90 mm diameter by 6 m high perspex column, built and initially operated by staff from CRA Advanced Technical Development. This column was found to have insufficient retention time so, during the first half of 1989, Pasminco constructed and installed a 200 mm diameter unit of the same height. Extensive testwork was carried out using this column during the latter half of 1989 and early 1990. It was clear from the results that a grade improvement of between 1 and 2 per cent (absolute) would be achievable. The effect of column cleaning on overall recovery was not established with the same degree of confidence, so the proposed new circuit is to include one of the existing banks of OK8 cleaner cells as a scavenger on column tailings. The test work provided sufficient data for preliminary design work to begin in May 1990 and commissioning of full scale zinc cleaner columns is planned for mid 1991. This paper summarizes the results and describes some of the experiences with column flotation at the Pasminco South Mine.

Jan 1, 1991

By Bailey S, Avraamides J, Jayasekera S

The anodic dissolution of iron from three different Western Australian reduced ilmenites was investigated using the carbon paste electrode technique. A characteristic current-potential diagram, called a cyclic voltammogram (CV), was obtained for each of the reduced ilmenites. The shape of the CV measured for all three reduced ilmenites was strongly time dependent. The effect of electrolyte composition and temperature on the CV of one reduced ilmenite was also investigated. The results suggest that the initial surface of iron in reduced ilmenite is slow to dissolve and that chloride ions and higher temperatures accelerate the dissolution of this initial surface layer. However, after removal of this layer, the dissolution rate was essentially independent of the electrolyte composition and the temperature.

Jan 1, 1996

By N G. Corner

A sea bed sampling programme by CRA Exploration Pty Limited over an area of 12 000 km offshore from Westland, Southland and Otago, New Zealand, led to the discovery of the Harvester Prospect, an area of some 67 km2 which averaged 189 mg/m3 gold in surface samples. This area was in water depths of 70 to 106 m and contained a high grade core of 33 km2 which averaged 283 mg/m3 gold. The gold recovered was fine grained, averaging 124 microns, and indicated a potential resource of approximately 10 t of gold per metre of thickness. Interpretation of existing seismic and geological data suggested that the gold anomaly may be associated with a unit of sediments 10 - 40 m thick, probably deposited during a lower sea level stand. Two initial attempts at vibrocoring the anomaly produced inconclusive results. In 1989 a much more powerful vibrocorer with scaled up support facilities and a dedicated 24 h turnaround laboratory were employed. The final results clearly showed that the gold was from an uneconomic surface enrichment.

Jan 1, 1990

By J F. C L Costa, J C. Koppe

The goal of this study is to characterise co-processed clinkers by identifying the most common minor elements, their distribution in the clinkers and possible effects on the mineralogical properties of the same. The results show the presence of an elevated content of transition metals, especially manganese concentrated in the matrix (up to three per cent) of the clinkers. Anomalous concentrations of arsenic have also been detected, especially at silicate crystal edges. The results indicate that the tracer elements can perfectly be associated to the mineralogical characteristics of the clinkers.

Jan 1, 2008

By Anderson J. M, Gillies A. D S, Jones N

There are a number of current theories in relation to methane migration and emission into workings following underground coal mining activity and some controversies do exist. Mining causes changes in the stress regimes in surrounding strata and results in fracturing. Permeability increases and methane flows into workings under a pressure gradient. The effects of stress on permeability depend on the physical properties of the coal and surrounding strata. Methane emission also depends on the original methane content and the proportion which will be liberated. There are several methods for determining in situ methane content and desorption characteristics of coal samples and several methane prediction methods but clearly more research is necessary to achieve an adequate predictive model.

Jan 1, 1992

By S Youds

The backfilling operation at Olympic Dam mine supports a 9.8 Mtpa underground Long Hole Open Stoping (LHOS) operation. It involves a combination of Cemented Aggregate Fill (CAF), surface rockfill and underground rockfill. The fill material is introduced from the surface via boreholes into the top of the stopes. Due to the deleterious effects of the dust and the thickness of the atmosphere in the stope it is not possible to view the filling process either at optical or infrared (IR) wavelengths. The need for a means to measure the filling process is driven by the placement of both rock and CAF fill in the stopes. The large volumes and high relative cost of CAF makes the minimisation of CAF fill a business priority. Incorrect filling can lead to the sterilisation of ore reserve. The use of millimeter wave radar to view through the haze to give real-time data on the relative positions of the different fill masses is being developed as an in-stope fill monitoring device. This paper reviews the salient points of the technology and its potential use in the backfilling operation at Olympic Dam. The broader potential of this technology for use in the mining industry by æseeingÆ through water and dust laden environments such as that found in stopes and ore passes is also discussed.

Jan 1, 2002

By A J. Tucker, L Bottomley

The principle objective of development mining is to create thoroughfares that can be accessed by personnel and machinery for the entire life of an underground mine. The drill and blast process, being the primary method used when creating these thoroughfares, needs to be able to adequately fracture the rock to be removed whilst at the same time minimising any damage that may be sustained to the rock surface that remains. This process of damage prevention is known by a variety of different names including smooth blasting, sculpture blasting, contour blasting and controlled blasting. Whilst the terms are different, the objective is the same and that is to reduce and better distribute the explosive charges to minimise stressing and fracturing of the rock beyond the neat excavation line. The process in this report will be referred to as perimeter control blasting. This paper will discuss the benefits of using perimeter control blasting in a development mining operation and the theories that govern how these blasting techniques work. The methods that are used to implement perimeter control blasting will also be addressed, paying particular attention to how these blasting techniques have evolved, spawning new and improved perimeter control products. Finally some attention will be given to the process of optimising perimeter control blasting in any underground mining operation.

Jan 1, 2005

Studies of the minor element content of sphalerite and pyrite have generally been concerned with individual deposits or localised groups of deposits. However, a small number of more regional investigations have been reported (e.g. Davidson, 1962; Groves and Loftus-Hills, 1968; Loftus-Hills and Solomon, 1967; Price, 1972; Bralia et al., 1979) which have used the minor element abundances to evaluate the petrogenesis and geological affinities of diverse ore types and to fingerprint metallogenic provinces (e.g. Ivanov, 1964). While generally held to be valid, some doubts have nevertheless been cast on the reliability of minor element abundances in petrogenetic deliberations (e.g. Mercer, This paper reports on the distribution of he. Cpl and Mn in sphalerite, and Co, Ni and Mn in pyrite, from sulphide mineral occurrences within the "eugeosynclinal" prism comprising the New England Region of north-eastern New South Wales and south- eastern Queensland (Fig. 1). The occurrences examined are representative of two well-defined styles of mineralisation (Stanton et al., 1974) within which clear patterns of ore-rock distribution give rise to specific metal associations (Herbert. 1977).

Jan 1, 1987

By U Rehm

The biggest hard rock double-shield tunnel boring machine (TBM) in the world, with a diameter of 12.4 m, is currently excavating the North-South Bypass, which includes a crossing under the Brisbane River, Brisbane, Australia, to relieve the often congested road traffic in the city centre. Ten years ago a 10.7 m Mixshield giant helped to handle the Olympic Games in Sydney linking the airport with the city centre for an improved transportation of fascinated visitors. In Shanghai, currently the biggest TBM in the world with 15.43 m diameter presents excellent performance rates; and in Paris a convertible Mixshield could be quickly changed from earth pressure balanced (EPB) to slurry type in order to handle the very heterogeneous ground conditions. In Madrid a 15.2 m EPB giant finished its tunnel job four months ahead of schedule. Large-scale TBMs have proved their economic and innovative potential to create the current and future underground architecture of mega-cities. TBM technology has made further large innovative steps in the last decade. State-of-the-art is a TBM for very heterogeneous ground conditions comprising hard and soft rock with additional high groundwater pressure. The machine concept is adapted to the various ground conditions and allows for a quick and flexible application. Ground treatment by means of additives developed to a helpful tool in this connection. To meet the special challenges of urban tunnel projects of nowadays it is of very high importance, beside applying highest developed technology of TBM, to have a comprehensive technical support during the project phase and to develop positive relationships between all participants of the project which last longer than only for one project.

Jan 1, 2008