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By Spark R. F

The copper deposits at Pernatty Lagoon are predominately djurleite-digenite bodies beneath the permanent water table, and chrysocolla-atacamite-malachite above the permanent water table. The minerals havebeen deposited as sheets, lobes, and pods in zones suggestive of permeability channels or permeability basius with respect to groundwater circulation.Pyrite is deposited in the form of framboids, which reflects its biogenic origin. Copper-iron sulphides deposit by replacement of pre-existent pyrite, and rarely by direct deposition. The latter mode of formation results in complex crustification bandings of chalcopyrite, bornite, sulphur rich bornites, digenite, and blue remaining covellites. The copper-iron sulphides appear to reequilibrate under constrained oxidation, resulting in an iron depletion and associated copper enrichment, the final product of which is a djurleite-digenite assemblage and associated with goethite. Where copper mineralization/ host rock relationships have rendered the rocks entirely impermeable to post ore groundwater movement, then the copper-iron sulphides are preserved as the ore assemblages.Minor and trace minerals observed include sphalerite, carrollite, galena, wittichenite, and possibly tetrahedrite in the primary ores. In the oxidized ores cllprite, tenorite, and trace brochantite have been found.

Jan 1, 1976

This paper deals with the Australian taxation laws, and in particular the income tax laws, as they apply to mineral exploration and development both in Australia and off-shore. The Australian tax laws are imposed principally at a Commonwealth level. The most important Commonwealth taxes are Income Tax, including Capital Gains Tax, Fringe Benefits Tax, Sales Tax, Customs Duty, Excise Duty and Bank Accounts Debits Tax. The States of Australia impose Stamp Duties and Financial Duties, Payroll Tax and Land Tax. The Australian Income Tax Law including Capital Gains Tax, is the most significant tax in the country. The principal features of the income tax law are as follows: tax is imposed on a taxable income being the assessable income less allowable deductions; a full imputation system of company tax applies; a foreign tax credit system applies to both companies and individuals; capital gains are taxed as income and subject to income tax rates but the gain is inflation adjusted. Australia has negotiated tax treaties with most of its trading partners based on the OECD model; and special tax concessions apply to the mining industry.

Jan 1, 1987

By T Akiyama, J A. de Castro, H Nogami

Blast furnace is a countercurrent moving bed reactor that produces pig iron from iron bearing materials like pellet, sinter or lump ore. The furnace has cylindrical shape and the lump solid materials are alternatively charged onto the top of the furnace. Hot air is introduced through tuyeres that are set on the lower furnace wall. Auxiliary fuels (pulverised coal, oil or natural gas) and raw materials (fine ore or fluxes) are injected into the furnace with blast air from the tuyeres. In front of the tuyeres, coke particles react with oxygen in the blast air and generate carbon monoxide. The hot reacting gas heats up the lump solids and reduces iron oxides in the upper furnace. In the middle height of the furnace, the reduced iron and slag are fused by the combustion heat and form the cohesive zone. The molten iron and slag that are generated in this region trickle down through the packed bed of coke particles and flow into the bottom of the furnace. Therefore, the flows of gas, lump solids and liquids exist at the same time in the lower part of the blast furnace.

Jan 1, 2000

To discuss this relationship both the problems of the mechanisms of ore accumulation and the origin and cause of volcanism must be faced. Volcanic activity is associated with hydrothermal activity but the causes of volcanism are inseparable from the problems of the origin of magmas generally. To be more in accord with the inevitable reaction between water and silicates at high temperature, it is suggested that reconsidera- tion be given to the role of water in magmas such that our general concept of magmas becomes one of hot hydrous pastes rather than melts with water in them. It is claimed that a general concept of magmas as gelatinous hydrosilicate masses is a far better assumption because the rheological and diffusive properties of such materials enables an adequate explanation of a greater number of observations. It is consistent with the mergence of magmatic and metamorphic rocks and requires low to modest temperatures at the time of liquifaction allowing convergence with mobilised and disturbed sediment masses. The physical and chemical properties of both wet sediment pastes and magmas envisaged as hydrolised silicate masses are entirely dependent on the enormous internal surfaces of their disordered solvated components. Mechanical disturbance, such as reliquifaction

Jan 1, 1974

By T Leach, I Pringle

The Bowdens Silver Deposit is a low sulfidation epithermal silver-base metal deposit that has formed on the northern margin of a hydrothermal system within air-fall breccias, ignimbrites and crystal tuffs of rhyolitic composition. The deposit lies near the north-eastern margin of the Lachlan Fold Belt and the rhyolitic host rocks are of Early Permian age. The silver mineralisation occurs as flat-lying zones of disseminations and silicic fracture-filling within the Rylstone Volcanics and is closely associated with sulfides of iron, arsenic, lead and zinc. High-grade silver mineralisation is also found in steeply-dipping fracture zones which host banded sulfide veins. Studies of the alteration products indicate that high temperature fluids, flowing from south of the current project area, resulted in quartz (¦adularia) û illite/sericite alteration. Cool, low pH steam-heated waters on the northern and eastern margins of the prospect area resulted in siderite û smectite-illite clay û Fe-carbonate û marcasite û kaolinite alteration. Mixing of the two fluid types resulted in the deposition of iron and base metal sulfides, a decrease in both sulfur activity and pH of the mineralising fluid, and subsequent silver mineralisation.

Jan 1, 2004

The copper deposits at Pernatty Lagoon are predominately djurleite-digenite bodies beneath the permanent water table, and chrysocolla-atacamite-malachite above the permanent water table. The minerals havebeen deposited as sheets, lobes, and pods in zones suggestive of permeability channels or permeability basius with respect to groundwater circulation.Pyrite is deposited in the form of framboids, which reflects its biogenic origin. Copper-iron sulphides deposit by replacement of pre-existent pyrite, and rarely by direct deposition. The latter mode of formation results in complex crustification bandings of chalcopyrite, bornite, sulphur rich bornites, digenite, and blue remaining covellites. The copper-iron sulphides appear to reequilibrate under constrained oxidation, resulting in an iron depletion and associated copper enrichment, the final product of which is a djurleite-digenite assemblage and associated with goethite. Where copper mineralization/ host rock relationships have rendered the rocks entirely impermeable to post ore groundwater movement, then the copper-iron sulphides are preserved as the ore assemblages.Minor and trace minerals observed include sphalerite, carrollite, galena, wittichenite, and possibly tetrahedrite in the primary ores. In the oxidized ores cllprite, tenorite, and trace brochantite have been found.

Jan 1, 1976

By Kidd A

The operations of Minerals Mining and Metallurgy Limited's (MM) South mine including both the mining and metallurgical aspects are described. After treating the history of the company, the geology of and the mining of the open pit are given including sections on pit design, mine planning and grade control. Details of the metallurgical process develognent lead into the current treatment practice and then sane thoughts on future programmes are presented.

Jan 1, 1983

Australasian mining companies expect a high standard of professionalism from their metals exploration teams. They also have, increasingly, a global perspective, employing explorationists of diverse cultural backgrounds and operating in diverse environments. Human resource development (HRD) of these professional explorationists needs to address all personal facets of functioning independently and interdependently in a modem working culture, as well as the needed technical competency. Creation of a learning organisation to promote this development is critical. Organisational consultants can support managers and supervisors as mentors facing the wide spectrum of development required by the explorationists; mentorship and guidance counselling can then complement training in the maturing of professionals from technical competence to professional independence and interdependence. Empowerment and clearly stated expectations are keys by which professionals can learn efficiently and effectively.

Jan 1, 1996

The patented "Epytensic" pump of Minnovation Ltd, a multiple piston pump, is used widely on shearer loaders and by partial high pressure watcr jet cutting strategically in relation to cutter picks not only improves cutting rates, but saves power and increases the life of gearboxes and picks, as well as improving dust suppression. The "Face Side Pump", also a piston pump, located on the ranging arm gearhead has advantages over gateroad pumps and shearer body pumps. The "Extraction Drum", hydraulic air mover system, linked with the above innovations and high pressure water, have further advantages in methane and dust removal. Some modifications providing these systems need workshop applications but most are possible underground with minimal changes to shearer profiles and advantages of minimising hosing, along with the other advantages stated.

Jan 1, 1991

By Grieveson P, Rajakumar V

The reduction of an ilmenite concentrate with coal at 1000, 1050 and 1100¦C was investigated using thermogravimetry and X-ray diffraction, optical microscopy and electron probe microanalysis of the product. The effects of temperature, coal particle size, addition of ferric chloride and preheating of the concentrate in argon on the reduction kinetics and mechanism were determined. The rate of reduction increased significantly with temperature and was enhanced by the addition of the catalyst. The morphology of the iron was primarily determined by the degree of weathering of the particle. Significant coarsening of iron was obtained in the dense particles by the addition of ferric chloride. The sequence of reduction and the enhancement in the rate of reduction by preheating the concentrate in an inert atmosphere are discussed.

Jan 1, 1991

By Whincup P

Hilton deposit comprises en-echelon silver-lead-zinc orebodies with reserves in excess of 50 million tonnes. The host rock to the ore is a dolomitic and pyritic shale/siltstone which dips steeply west. The shale/siltstone is deeply leached and porous, particularly over the Ore Zone where the depth of leaching continues down to 440 m below surface, and constitutes an extensive permeable aquifer system containing a large volume of saline acidic groundwater. Initial production commenced at Hilton in 1987 well below the aquifer. A dedicated dewatering and monitoring programme is in place to ensure security of stoping operations and allow extraction of ore close to the leached zone in future years. Dewatering is undertaken from controlled bores from underground sites. Mine groundwater discharge is presently at the rate of 4000 kl/day with plans to increase to 8000 kl/day. An additional 2000 kl/day of fill and service water and water from secondary aquifers is also pumped from the mine daily. Although recharge rate to the aquifer is minimal, studies indicate that due to the size of the aquifer and future extensions to mine development, dewatering will be a life of mine activity. The investigations which have been undertaken to determine optimum dewatering techniques and schedules are described. These include production bore tests, mine planning constraints and computer aquifer modelling. Gravity geophysical techniques have been successful in delineating the lateral and vertical disposition of the aquifer. The mine dewatering schedule, whose principal component is underground mine drainage, is also outlined.

Jan 1, 1988

THE millng methods employed in the Mount Lyell Mining and Railway Company's mines are, perhaps, less known to the milling world than those of other important districts, due to the geographical remoteness and isolation of the Mount Lyell field,but they present many features which are unusual, and should be of interest to the mining engineer. Typical mining is carried out on an open-stope system, details of which are the result of local experience and evolution, and of which the outstanding feature is that the ground is so worked as to be largely self-supporting by virtue of domical form given to the stope roofs. It is locally termed "rill" stoping,' but differs widely from what is generally understood by that designation, chiefly in that the "rill" or slope is developed in every direction from a central focus, and not merely in directions followllig the strike of a lode or ore-body whose longitudinal dimensions are very much greater than its width. Such terms as "donie stoping" or "arched-back stoping" would be more appropriate and descriptive.The company's active operations' at the present time extend to the Mount Lyell and North Lyell mines, and, though the fundamental principles of stoping methods are the same in each, the dissimilarity of the ore-bodies, both in nature and mode ofoccurrence, necessitates considerable variation as to details to meet the respective conditions. The Mount Lyell pyritic body lends itself to the adoption of the .system in its simplest and almost ideal form, and a description of stoping in this mine willserve best to illustrate it, while later reference to details of practice in the North Lyell mine will indicate how it may be varied to meet more difficult circumstances.

Jan 1, 1915

The (SA Mine at Cobar produces a mix of copper and copper lead and zinc ores fran long hole open stopes. Primary jaw crusher product is fed to two parallel primary autogenous mills followed by a secondary ball mill. Each mill operates in closed circuit with cyclones. Grinding equipment and the main operating variables are described. Copper lead and zinc flotation concentrates are produced sequentially. The control systems and operating strategies are described.

Jan 1, 1983

By Nelson G

The construction and placement of tunnels by means of jacking is continually advancing. This paper presents an outline of the construction of a major highway tunnel placed by a combination of mining and progressive placement by hydraulic jacking of precast units. Features of the project were the relatively shallow ground cover between rail and road routes over the tunnelling and jacking operations and also the weight of tunnel sections to be moved into position.

Jan 1, 1993

Efficient performance of pulp lifters to discharge ground rock is critical to the effective performance of SAG and AG mills. The paper covers developments in the design of pulp lifters and associated grates, of both conventional straight-radial and curved types, and of the inner discharge cone. Issues covered include the discharge performance of both the slurry and rock components of the discharge, reverse flow back into the mill through open grates and backflow down the pulp lifters of material that fails to discharge from the mill. The design experience is interpreted in the light of developments in particle flow modelling of the flow of charge in pulp lifters.

Jan 1, 2004

To carry out its responsibilities the SECV needs to manage the visual environment effectively. Every land oriented decision effects what we see and the value in pursuing visual excellence is supported by informed opinion, widespread community interest and evidence of cost- effectiveness.By knowing how we perceive the landscape and then changing or conserving it we can assist in fostering a positive mental image of a countyside which is welcomed by the local and regional community.It is useful to examine key design elements and the value we place on visual impressions in relation to three significant SECV rehabilitation projects, at Loy Yang, Newport and Morwell Open Cut.

Jan 1, 1992

BHP Minerals Ltd operates an open cut iron ore mining operation on Koolan Island, off the coast north of Derby in the Kimberley region of Western Australia. The mine comprises a number of pits, the largest of which is situated adjacent to the coast on the southern side of the island. The lowest bench is currently at RL +2 m, and the mine has planned ultimate depth of RL -82 m. Mining has already extended below the pre-existing water table level, and below mean sea level. In 1984, an extensive program of drilling, geophysics and test pumping was instigated to evaluate the aquifer hydraulic properties and the nature of the groundwater flow regime. With the aid of computer modelling, predictions have been made of the likely dewatering and depressurization requirements, and a conceptual pumping and drainage system has been designed.

Jan 1, 1986

By Slechta JJ

The performance of a hydrocyclone treating fine coal has been examined over a wide range of feed and operating conditions.The results were expressed in terms of partition curves from which the water split to the oversize flowstream,the corrected separation size and reduced partition curves were determined-.The following conclusions were obtained. (a) The water split to the oversize flowstream was found to be dependent upon the vortex finder and spigot diameters of the cyclone and the flowrate and solids content of the feed slurry. (b) The corrected separation size was dependent on the solids content of the feed,and the vortex finder and spigot diameters.The hydraulic pressure (or flowrate) of the feed slurry did not have a significant effect.This phenomenon could be explained in terms of crowding of the particles at the Spigot.

Jan 1, 1984

Dynamic shocks, which occur in mine hoisting systems have been measured by various investigators over the past 30 years. In 1966 the most intensive analytical investigations were being planned in Bochum, Germany, where equipment then was being constructed to measure the power generated in any particular dynamic shock. Between 1953 and 1956, in Broken Hill, N.S.W., accelerations of the shaft conveyances were measured and analysed. The "effective mass" of the conveyances at the time of the shock was then and still is considered as indeterminate and not easily measured. It is believed that probable peak forces can be determined by the product of the static mass and the accelerations. The subsequent problem of the elimination of the dynamic shocks becomes one of possibly increasing the frequency and thus reducing the amplitude, after identifying and evaluating the shock generators. In addition, judicious use of the clearance between the shaft conveyance and the guide, as a zone in which to absorb vibrations, is a factor which has been overlooked in earlier investigations on This topic.

Jan 1, 1971

The most critical step in the development of any mining project is the completion of a feasibility study. The feasibility study has one primary goal; to demonstrate that the project is economically viable if it is designed, constructed and operated in accordance with the concepts set forth in the study. Starting from a mineral resource data base, the feasibility study will define the ore reserves, the mining methods, the mineral processing concepts and the scale of the project. The disciplined activity of developing a feasibility study leads the proponent to examine every aspect of the project, many of which might otherwise be ignored. All technical concepts will be established and the corporate philosophy with respect to organisational structure, social and environmental responsibility, infrastructure contributions and financing will be determined. All the major decisions about how the project will be developed are made during the feasibility study. The success of the project will then depend upon the assumptions and decisions in the feasibility study and the ability and empowerment of the development team.

Jan 1, 1997