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By Gray J, Krouse HR, Changkakoti A, Kwak TAP

The Dachang tin field with more than one hundred million tonnes of ore at 1% tin and 3% Zn is one of the largest tin fields in the world. It comprises five carbonate replacement tin deposits, of which the Changpo deposit containing about 80 million tonnes of ore at about 1% tin is the largest deposit. The deposit, hosted by middle Devonian limestone, argillaceous limestone and black shale, is genetically related to the Longxianggei granite.The oxygen, hydrogen and carbon isotope data of minerals, rocks and fluids suggest a magmatic fluid which evolved during the crystallization of the Longxianggei granite. Mass balance calculations show that the depletions observed in 180 and 13C values of calcites from the ore bodies to the country rocks were due to continous isotopic exchange reactions between the magmatic fluid and the marine limestones at different W/R ratios and between 300 and 600¦C.

Jan 1, 1990

By Blair J. R

In the Bayer process, bauxite is leached with caustic soda, forming a solution of sodium aluminate, from which hydrated alumina is precipitated. The efficient operation of the continuous form of this process requires that the concentration of caustic soda be controlled. A computer simulation of the concentration of caustic soda has been conducted to provide information, regarding the dynamic behaviour of caustic concentration, which is not available from normal plant data. The basis of the simulation is a state- space model of an alumina refinery, linearized about the normal operating condition. The formulation of the model, with the relevant approximations and assumptions, is outlined. The simulation of the mudwash section of the. plant is described in detail. A continuous model of the mudwash, having time-varying coefficients, was driven using operating data from an alumina refinery. The modelled response showed reasonable agreement with the recorded plant response.

Jan 1, 1977

of the multitude of physiographic problems of immediate interest in volcanic terranes, it is the origin of the magma forming the magnificent volcanoes that is perhaps the most mysterious. Unlike anywhere else on earth, the possible locations of magma production beneath the convergent margins are strongly limited in depth and areal extent. Yet the exact process by which magma is produced still stands elusive, even in light of tremendous gains in analytical and physical insight. The principal aim here is to discuss some of what has been revealed about the physics and chemistry of the origin and evolution of island are magmas.

Jan 1, 1987

Discovered in 1896, the Sons of Gwalia orebody is located in a ductile mylonite zone within a sequence of Archaean pillow metabasalts and minor metasediments of greenschist facies which are variably sheared.The ore zone has good continuity, being 110 m wide and 500 m long, dipping 45 degrees east and plunging 70 degrees to the south to a depth of 1500 m downplunge. A strongly-developed foliation is present together with a prominent lineation paralleling the plunge. The mylonite zone consists of unmineralised chlorite schist and a 'U' shaped mineralised zone of chlorite-sericite schist with varying amounts of quartz-carbonate as veins parallel to foliation, boudins, and locally as massive quartz-carbonate. Pyrite is the dominant sulphide present.Grade control utilises RC holes on a 10 m x 10 m pattern, with infill blast rig holes 5 m deep where necessary.Some visual control of ore boundaries is present and, combined with good ore continuity and a knowledge of the structure of the orebody, enables cost-effective grade control to be achieved. To-date, over three million ounces of gold have been produced from the orebody.

Jan 1, 1993

Synthetic seismograms of reflectivity method and some field records available are studied to detect the amplitude anomalies at the interface of the gaothermal reservoir the gas and/or oil boundary, and the underground tunnel. The first arrival of PO wave on the P-SV record are weak and emergent while those of P wave only rotated with respect to an incident angle are clear. This can, be explained by means of the energy loss of P-SV wave conversion. The primary reflections of P waves about depth fade away as compared to SH waves which do not perform any conversion, although they hold high attenuation in the fully saturated fluid layers. Reflection of comparable strength is present at the P-wave and S-wave... boundaries, but gas-saturated zones correlating with P wave bright spots do not show equivalent attenuation anomalies. Thus the comparative technique of P-SV wave and SI i wave records is very useful to indicate the strong amplitude anomalies at the boundaries of sealing targets.

Jan 1, 1990

Australia is the Western world's largest producer of alumina, supplying one third of total needs. Western Australia's South-West has the greatest concentration of alumina production in the world, with a current annual production rate in the region of 6.8 million tonnes per annum, over 20 per cent of the total supplied to market economies. The value of this production in 1989-90 was 2.34 billion dollars, a very significant contribution to the economy of the State (1). This is despite the fact that the bauxite from the Darling Range is the lowest grade that has ever been commercially exploited, and despite the geographical isolation of the region. It is therefore of great importance to the National and State economies that this industry retain its competitive edge, particularly in the current times of economic downturn. One essential ingredient of this competetiveness is technology and innovation, which can be assured by the committment of the industry to an active program of Research and Development, with support from the public sector as Appropriate.

Jan 1, 1991

The economically significant seams in the Bowen Basin fall into four age groups, two in the Lower Permian and two in the Upper Permian. Coal deposition in the Galilee Basin did not commence until late in the Lower Per- mi-an and persisted into the Upper Permian. The Lower Permian and early Upper Permian coalfields of the Reids Dome Beds, the Collinsville Coal Measures and the Fair Hill-German Creek Formation are restricted to the west flank of the Bowen Basin. The uppermost Permian Rangal-Elphinstone-Baralaba Coal Measures have widespread distribution across the northern half and on both flanks of the Basin. Coal Measures in the subsidiary basins at BlairAtho/ and Ca/en were probably deposited at the same time as the Collinsville Coal Measures. The structure of the north west flank of the Bowen and the east flank of the Galilee Basin is essentially simple, but in the remainder of the basin doming and faulting complicate the structure. Also, bordering a large sec- tion of the east flank, is the Dawson Tectonic Zone, where the beds are tightly folded and faulting is intense. Cok- ing of seams is common in the northern sector of the Basin associated with igneous intrusion. With the exception of the Duaringa Basin on the east flank of the Bowen Basin, Tertiary sediments and basalt flows are more common at the western basin margin. Thick deposits of Tertiary sediments also occur in the south of the Galilee Basin. Con- sequently, coal subcrop, especially in the older, more westerly situated, coal measures is often at depths in excess of 100 m. East of this, the depth of weathering can be as shallow as 13 m and most of the coal subcrop is acces- sible to mining by open cut techniques. Coals deposited in the early Upper Permian are commonly more vitrain rich than those above and below. In the Bowen Basin, coal rank decreases from the north west to the south east, that is, from the semi-anthracites associated with the Dawson Tectonic Zone to the sub-bituminous coals of the southern Galilee Basin.

Jan 1, 1975

By D Hodder, M Hoskins, A Rofe

Pasminco Century MineÆs slurry pipeline was commissioned in November 1999. It currently transports zinc and lead concentrate slurries in batch form to the Port facility, 304 km away in the Gulf of Carpentaria. The Pipeline and the Port have gone through several stages of continuous improvement to match the successful ramp-up of the concentrator. Improvements in the Pipeline and Port Operations have included: commissioning of the first slurry pipeline that delivers two products in the same pipeline in batch mode; management of batches throughout the pipeline and port system to minimise cross contamination of both concentrates; operation of the slurry pipeline to achieve high availability of the system; operation of the pump station interfaced with preventive maintenance to minimise unplanned shutdowns; continuous monitoring of pressures throughout the single-station, 304 km slurry pipeline; redesign of the Rotary screw feeder; redesign of the Dryer Control System; installation of a larger Induced Draft Fan; optimisation of the dryer internals to achieve a product of narrow size distribution and pellet integrity; redesign of the stockpile ventilation system; and the development of a surface sealant. This paper describes the early commissioning of both the Port and the Pipeline and the continuous learning and Quality Improvement Project initiated at the Port to focus on concentrate quality given the propensity of the fine concentrate to self-heat during storage.

Jan 1, 2003

By Senanayake G

A sample of crude copper powder produced by the CLEAR Process was refined by dissolution and recovery in sulfate media using the Parker Process. The Parker Process offers an alternative method of copper recovery to electrorefining and allows a range of Eh and pH conditions to be used to provide further discrimination of impurities. High purity copper powder was recovered by the Parker Process even in the presence of added impurities when the Eh and pH was maintained near constant throughout the refining step.

Jan 1, 1984

The kinetics of desorption of nitrogen from molten iron were investigated using the electromagnetic levitation technique. The respective influences of gas flow rate and surface active element (S) were examined. A second order behaviour with respect to the nitrogen concentration in the melt prevailed at all experimental conditions. Sulphur had a marked inhibiting effect on the desorption rate. The experimental results on the rates of nitrogen desorption have been interpreted with the aid of a reaction mechanism consisting of a sequence of elementary steps.

Jan 1, 1991

By Breen AM, Phelan JM, Doherty RJ

Early in 1990, Pancontinental Resources (Base Metals) Pty Ltd commenced flotation treatment of ore from the complex copper-lead-zinc sulphide orebody at Thalanga, 65 km west of Charters Towers in North Queensland. The orebody consists mainly of primary sulphide ore but also contains a substantial proportion of supergene ores which are being processed during the first year of operations. The supergene ores are of three main types, designated as A, B, and C. Supergene A ores are essentially copper ores, containing little lead and zinc, while B and C ores are copper-lead-zinc ores with different degrees of alteration of the original chalcopyrite and different ratios of copper to zinc content. Copper is present in the supergene ores mainly as chalcocite, digenite and covellite. Lead and zinc occur mainly as galena and sphalerite respectively. This paper describes the development of flotation plant practice, aided by laboratory testing, to process the supergene ores. The major challenge in treating these ores is that a varying proportion of the sphalerite is naturally activated and is not easily depressed in flotation by the conventional zinc depressants.

Jan 1, 1991

By Tran T, Young D

During the processing of gold, effluents that are discharged into the tailing dams contain free cyanide, metal cyanide complexes of zinc, copper, iron, etc and their oxidised products such as ammonia, cyanate and thiocyanate. A knowledge of how different cyanides behave in the solution is vital to metallurgists working in the area of cyanide waste treatment. Although the free cyanide ion is not stable in aqueous solutions and is expected to degrade in a natural environment by atmospheric oxidation, the metal cyanide complexes, especially of iron, are very stable. The CHEMIX program from the THERMODATA package, developed by the CSIRO Division of Mineral Products, was used to evaluate various copper-cyanide and iron-cyanide systems. The simulation of these systems show how the free cyanide and cyanide complexes behave at different conditions of solution composition and acidity (pH).

Jan 1, 1991

By Ma F, Yang Q, Ujihira M

The effect of stresses and acoustic emissions on the gas permeability of coal was investigated in the field and the laboratory in order to find an estimative method of the practicability of gas drainage. In the field, acoustic emissions and gas emissions during gas drainage drilling were monitored tentatively at some coal mines in Japan and China.In the laboratory, acoustic emissions from coal specimens in addition to gas permeability were measured during the triaxial compression loading in order to interpret the results monitored in the field. Besides, the opening of gas permeation channels in coal was considered on the basis of the experimental results.

Jan 1, 1991

The late Carboniferous to early Permian Featherbed Volcanics cover an area of about 3000km near the western margin of the Hodgkinson Basin, in northeastern Queensland. The dominantly ignimbritic volcanic rocks are mostly confined to a single, composite, volcano-tectonic depression, but, along with the associated intrusive rocks, may be divided into two main groups: late Carboniferous I- type rocks and early Permian A-type rocks. Late Carboniferous I-type andesitic to rhyolitic ignimbrites and minor andesite lava crop out in the southeastern, southern, and southwestern parts of the complex, mostly confined to a basin-like depression, or "sag" structure, and are associated with coeval dioritic (and rare gabbroic) to granitic intrusive rocks. Extensive Sn, W and base- metal, and some Au, mineralisation are associated with these rocks, particularly in the southeast. The main part of the complex is of early Permian age, and consists almost entirely of A-type rhyolitic ignimbrite and relatively minor volumes of lava intruded by a peripheral ring dyke of porphyritic microgranite and by resurgent-type plutons of porphyritic microgranite and microgranodiorite. These rocks are associated with sparse base-metal, Au, U, W, and Sn mineralisation.

Jan 1, 1987

High interest to basic-ultrabasic rocks is ex-plained by their specific, sutural, geotectonic po-sition and by deep level of generation of ultraba-sic magmas. These two factors allow us to treat this group of rocks as valuable source of informa-tion about the lower crust and upper mantle of the Earth. Basic-ultrabasic xenolith series is another source of information about the interior of the Earth. Detailed studies of the xenolith series give valuable material to geologists as to how endogenic deposits are fed and what is their source.Besides, the interest is explained by attempts to understand the relationship between basic-ultra-basic complexes and deposits of metalliferous and non-metalliferous mineral material.Absence of genetic boundaries in manifestation of metalliferous and non-metalliferous minerals, their temporal and spatial relationship allow us to treat the minerogenesis of ultrabasic complexes as a result of one ore-forming process manifested in Koryak-Kamchatsky, Sakhalin-Japanese, Ryukyu-Korean and Taiwan-Philippines island arc systems which re-present, in the opinion of the authors, one eastern Asian chain of the Pacific ore belt (Radkevich, 11)87).

Jan 1, 1990

By Siddall B

A brief review of the capabilities and practical limitations of blast simulation packages has been carried out. It is concluded that the simulators accurately reflect size distributions in the mid-ranges of 0.1 to 1.0 in, but are less reliable

Jan 1, 1998

By Mullens P

Recent advances in technology have allowed many of the problems of directional control of long diamond drill holes to be overcome. Three case histories are presented, from Cobar, Hilton North and Mount Isa Mine, in which careful hole design and the use of wedges and down-the-hole motors have allowed tight directional control of drilling. Substantial savings in time and cost were achieved in all three cases.

Jan 1, 1990

The Mt Keith Operation, 90 kilometres north of Leinster in the north-eastern Goldfields of Western Australia, was commissioned in October 1994. Based on a large tonnage, low-grade nickel sulphide orebody the plant was designed to produce 28 000 tonnes of nickel in a high-grade 20 per cent nickel concentrate. Following a successful and rapid start-up the operation is currently expanding to a throughput of ten million tonnes per annum (mtpa) ore and an annual production of 42 000 tonnes of nickel. This paper provides an overview of the Mt Keith Operation from commissioning to its present operation and Expansion.

Jan 1, 1996

The preconcentration of uranium ore by radiometric ore sorting at Mary Kathleen Uranium Ltd. is described. The operation of the ore sorting machines is discussed in detail and performance results obtained with the existing system are presented.

Jan 1, 1978

Aluminium in Australia, and in fact all round the world, is made virtually exclusively by the Hall-Heroult process, whereby the metal is derived from the electrolysis of alumina dissolved in an electrolyte comprising fluoride salts. It is the distribution and control of these inorganic fluorides during and after the reduction process which go to make up the bulk of environmental problems associated with aluminium reduction smelters. The emission characteristics of fluorides from the process, the occurrence and effects of fluorides in the environment, and the control techniques wnich are applied in industry, all need to be taken into account in assessing the overall environmental aspects of aluminium Production.

Jan 1, 1977