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By Bruce See J

Oxidation of artificial Imperial Smelting Furnace lead bullion was performed during cooling between 1180 and 820°C in order to attempt to produce a tin-rich dross.The addition of sodium carbonate together with stirring increased the tin content of the dross when oxidation was carried out with air or PbO on zinc-free bullion.Zinc in the bullion during oxidation resulted in a decrease in tin concentration of the dross due to zinc oxidation and copper entering the dross.

Jan 1, 1987

By Munro DL

The Mary Kathleen uranium deposit is in north-west Queensland, approximately halfway between the townships of Mount Isa and Cloncurry, at long. 1400 009 E and lat. 200 44' S. The deposit Iwas discovered by prospectors of the Walton McConachy Syndicate early in July, 1954, and climaxed a very intensive ground search by hundreds of part-time prospectors. during the uranium boom from March to July 1954ò Numerous small deposits, mostly in the vicinity of Mount Isa, were discovered in various rock environments, but Mary Kathleen is the only large deposit and, apart from a few tons of hand sorted material from the Milo lease, is the only deposit that has been worked. Exploration of the surrounding area, and proving of the economic worth of the deposit, were conducted from the time of discovery until February 1956 by a geological team camped near the deposit. Proving was carried out by drilling a pattern of vertical and inclined diamond drillholes at fifty-foot centres over the outcrop. An adit was driven eastwards through the deposit. Metallurgical research and design work in the South Australian Department of Mines Adelaide Laboratories were based on core samples and bulk samples from the deposit. The signing of a contract in March 1956 with the British Atomic Energy Authority to supply 4500 short tons of uranium oxide allowed mining to commence, and enabled the planned construction of water supply, township and treatment plant to proceed. The open out mine and plant are now serviced by a modern township, four miles away, which is connected to Cloncurry and Mount Isa by road. Although little field work has been done since the exploration phase, this paper differs in interpretation from a previous paper (Matheson and Searl, 1956) in that it is based on a revised structural inter- pretation (Compana, 1958), detailed mapping of progressive exposures in the open out, and a re-examination of diamond drill cores.\

Jan 1, 1968

For several decades miners have been obliged to maintain a vast supply of sharp steels at the working face to meet the hungry needs of rock-drills. In medium and large size mines this has meant the setting up of an organisation to store steels, to make and sharpen bits with all the complication and skill of forging, hot milling and heat treatment, and to transport sharp and dulled steels to and from the working face with all its labour, wastage, and inconvenience to other mining operations.In a mine with 250 rock-drills in use, a flow of more than 60,000 sharpened steels each month has to be maintained to keep the machines fully employed, so some idea of the magnitude of this problem may be grasped.For a long time it has been apparent that it is mainly the bit itself that wears, and many attempts have been made to reduce the enormity of the problem by providing detachable steel bits which could either be used once and rejected, or sharpened three or four times before rejection.At the same time metallurgists have striven to 'improve the quality of the steel and the heat treatment afforded it so that a bit, readily workable In a normal mine drill-shop, could be produced having a high resistance to wear and fatigue; but, although various alloy steels have been marketed, it is still usual to find many mines relying on a "straight" carbon (0.6 - 0.9% C.) steel for their drill steels.Since 1915 increasing use has been made of tungstencarbide as a cutting implement in the engineering industry. Where, on account of its great hardness and long life, it...

Jan 1, 1948

By Weller K. R, Trahar W. J

The Mount Lyell Company treats some 2.3 million tonnes of ore annually, mined from a number of orebodies on the field. Blended ore is essentially a quartz-sericite schist containing about eight per cent of pyrite and three per cent of chalcopyrite. Four-stage crushing and two-stage ball milling are followe by selective flotation for copper. Pyrite is recovered from the coarse fraction of dopper circuit tailings. A detailed survey involving examination. of 82 samples provided information on the size- by-size behaviour of the principal ore constituents throughout the grinding, copper flotation and pyrite flotation sections of the circuit. Results for the copper and pyrite flotation sections are presented in the paper, and it is shown that over half the copper reporting to the final tailing (5% of copper in the feed) is plus 100 microns and that the major pyrite loss is in the desliming cyclone overflow. These data proVide a basis for assessing potential methods of circuit optimisation.

Jan 1, 1977

By Riches N, Harbort G

The Jameson flotation cell was developed jointly by Mount Isa Mines Limited and Professor GJ Jameson of the University of Newcastle. The cell has been used in a number of cleaning applications within Mount Isa Mines Limited. In 1989 Peko Mines tested the Jameson flotation cell at the Warrego concentrator to upgrade recleaner concentrate. 2 x 1.4 m diameter Jameson flotation cells were installed in 1990. This paper describes the testing, commissioning and operation of these Cells.

Jan 1, 1991

The discovery of copper and nickel sulphides in the Riwaka Complex in 1967 led to considerable exploration activity by a number of companies. Various exploration techniques used by these companies are summarised and discussed. Activity of these companies shows that mineralisation is mainly confined to the southern, ultramafic section of the Riwaka Complex where geological mapping recognised sixteen units within, or associated with the Riwaka Complex. Significant pyrrhotite, pentlandite chalcopyrite mineralisation is restricted to biotite feldspar pyroxenites and to clinopyroxenite units. Lesser and more erratically distributed pyrite chalcopyrite pyrrhotite mineralisation occurs in poikilitic pyroxene hornblendites, melanocratic gabbros, and in marginal diorite lenses. It is suggested that a linear belt of layered ultramafic and mafic rocks described in Fiordland by Williams (1974) may be a southern extension of the Riwaka Complex. The Riwaka Complex has been classified as belonging to the Picritic subtype, (Tholeiitic suite), of Naldrett and Cabri, (1976), and as such it is concluded that it exhibits substantial potential for the discovery of economic copper and nickel deposits. It is considered that the complex is a multiphase differentiated intrusion emplaced in a major tensional fracture zone that developed in a relatively stable tectonic environment, namely a succession of middle Paleozoic shallow water shelf sediments. Based on sparse available evidence it is suggested that the Riwaka Complex was intruded in the lower to middle Permian. It is further suggested that the tensional fracturing was initiated by the onset of subduction process which were responsible for the development of the Permian volcanic arcs and ophiolite belt in the north west Nelson area.

Jan 1, 1977

By Struthers M. A

The basement contact zone, a major fault structure underlying the copper orebodies at Mount Isa, has a significant influence on orebody extraction. The zone is comprised of a variety of weak, barren lithologies which often create very difficult mining conditions, contribute to stope dilution, and have an adverse effect on concentrator recoveries.The geological characteristics of the contact zone are described, and the importance of timely, accurate geological information emphasized.A variety of mine design strategies have been employed to reduce the impact of the contact zone on orebody extraction. Some of these are discussed, together with current trends in the southern areas where orebody geometry and hence mining methods change markedly.Recent developments in ground support techniques, such as cable dowel reinforcement, have significantly improved ground conditions in the contact zone. An example of the methods employed to improve knowledge of ground behaviour is presented. The trend towards increasing automation and larger equipment requires larger excavations; consequently ground support practices and knowledge of ground behaviour must continue to advance. Rock mechanics investigations will remain an essential part of the mine design process.

Jan 1, 1990

The first stage in process design for coal preparation is a study of the coal seam and its associated features followed by an examination of the mining method to.be employed and the coal market requirements. Normally benefication is based upon the differences in relative densities of the coal constituents and asso- ciated ash forming components. Since initial liberation is obtained at a relatively large particle size, the size to which coal is crushed is more subject to the market requirements than to liberation studies. It is possible to estimate energy requirements for comminution and recoveries and product grades can be cal- culated following the interpretation of standard laboratory tests. Numerous units are available for the separation and concentration of the components of run of mine coal in- cluding jigging, dense media separators, and for the finer particle size fractions, flowing film separators, dense media cyclones and froth flotation.

Jan 1, 1975

Routine, in-pit geological mapping of highwall at Central Queensland Coal Associates (C.O.C.A.) deep strip mines has proved too slow for the increasingly greater highwall lengths which require mapping. This realiz- ation has encouraged the search for faster mapping methods and after trial of ground photographic methods has resulted in the adoption of interpretive mapping off stereo cover, oblique -- aerial photography. This entails using a Cessna 182 light aircraft flying at its slowest speed, the aerial meth- od finally employed consisting of two Vinten, air reconnaissance cameras mounted in parallel and simultaneously taking both colour and black and white photographs of the mine high- wall. The respective 1:500 scale enlargements produced from the 70mm format films combine to present the sharpest resolution attainable under the field conditions pertaining and such information on weathered material as only colour photography can fully render. Total costs for the aerial photography method are estimated to be about the same as those for conventional in-pit mapping. Whilst total costs are comparable, geo- logist's time for mapping a 10 km. length is reduced to less than half that for in-pit mapping (for Stage 1, fully accurate mapping) and accuracy and detail are greatly improved. A permanent, accurate record of overburden

Jan 1, 1981

By Brown K, Francis D

The Yallourn Open Cut Mine has recently commenced mining operations in the new East Field which will supply the 1450MW Yallourn W Power Station for the rest of its 30 year design life. The authors describe the design and implementation process followed during the rehabilitation of the areas disturbed by works associated with mining in the East Field. One area of the East Field, the old external overburden dump, has been of particular interest and is discussed in detail. A discussion on the fire protection considerations is included as these are critical and often misunderstood as being contrary to good rehabilitation design practice. Finally, the development of a master plan for the rehabilitation of the Yallourn Open Cut in general, incorporating the East Field work, is discussed.

Jan 1, 1992

In comparisons of a trial extruded brick containing 33 per cent coalwash and 67 per cent clay and a trial pressed brick containing 100 per cent coalwash with a standard extruded clay face brick, the mixed feed stock trial brick compared favourably with the standard brick. If a highly plastic clay is used to mix with the coalwash, satisfactory results are obtained in respect to dimension, strength, water absorption, efflorescence, resistance to salt attack, hardness, colour, weathering, mineralogy and porosity. Although a brick containing only coalwash can be successfully manufactured in a press, its mechanical and physical properties are inferior. This mixed feed stock brickmaking technology leads to the utilisation of a by-product with a potential saving of raw material costs. The extent of use is likely to depend on the proximity of the coal washery and the brickworks and the economicsof transportation costs.

Jan 1, 1992

By Komosa T, Muir D. M

Adequate levels of dissolved oxygen are essential for efficient gold dissolu- tion. The actual levels in plantpuips can be seriously reduced by the presence of oxygen consuming reactive minerals, and reduced oxygen solubility in saline water. The rate of gold dissolution is then limited by oxygen availability rather than cyanide. Ion selective electrode dissolved oxygen meters can give an effective indication of the relative oxygen saturation, but they are not able to give meaningful values of dissolved oxygen in saline water, without custom calibration curves. When the dissolved oxygen concentration is rate limiting, the addition of oxygen or peroxide can improve gold leaching kinetics as well as reduce cyanide consumption.

Jan 1, 1991

By Wagland D. G, Guo H

The Mt Whaleback orebody is in a complex geological regime. A good understanding of geological structure is essential during the design and implementation stages. The amount of information on the rock-mass condition available at the design stage is considerably limited. It is essential to validate the rock-mass properties used in the design during implementation. It is important to achieve integrity of the final pit wall during development and to maintain the integrity until the end of its designed life for safe and economical extraction of ore. The original geological model is updated by way of on-going detailed geological face mapping. Original design is reassessed and is modified based on any significant variations to the previously evaluated geotechnical conditions. Information gathered during design implementation provide tools for effective management of the pit walls. Controlled blasting techniques are employed in the final limits blasting. Presplit blasting is used in most limits blasts. Presplit helps to maintain the integrity of the wall by venting excessive gases from the limits blast. This helps to reduce bedding dilation by gas penetration. Also, it helps to define the design batter for the operators for final batter trimming. Pyritic shale needs special attention during blasting due to its reacting nature. Cablebolting is applied in selective areas to secure small-scale potential instabilities. During the development phase, pit wall monitoring instruments are installed. These instruments are used to monitor the performance of the wall during and after excavation of the slope.

Jan 1, 1995

Mathematical modelling of continuous rotary vacuum filtration has been limited by the wide range of variables and the absence of connecting equations linking the variables. The filter type and size, mechanical design and predicted performance are generally determined by laboratory leaf tests on representative samples of slurry, or plant samples from an operating filter. A model has been developed which includes the major process variables such as slurry feed rate and concentration, cake thickness, wash water and air flow rates, to predict the filter production throughput, cake moisture and residual solubles. Where possible the model incorporates well established equations relating form filtration, washing and drying rates of the filter cake. Where an equation has not been formulated, standard curve fitting programs have been used to establish an algorithm. The theoretical equations and the derived algorithms are defined in the text. A major feature of the model is that operators, metallurgists, process, mechanical and instrumentation engineers become more aware of the interaction of process variables, the principles of the equipment design and its limitations when operating at peak performance. The model has specific application in the alumina industry where a high moisture content of the filter cake can increase chemical losses and energy costs, and in the coal industry where overseas companies are insisting on lower export coal moistures.

Jan 1, 1989

The Honeymoon Well nickel sulphide deposits are located in the Agnew-Wiluna greenstone belt, about 45 km south of Wiluna. Both disseminated and massive sulphide nickel deposits are hosted by komatiitic rocks within the deformed and metamorphosed Honeymoon Well ultramafic complex. Fresh ultramafic bedrock is covered by up to 50 m of highly conductive transported material which greatly hampers both exploration and understanding of the bedrock geology. In the early-1970s, mineralisation was discovered by diamond drilling geochemical anomalies defined by wide-spaced percussion drilling over ultramafics that had been outlined by ground magnetics. Subsequent drilling has defined a resource of 158 Mt at 0.71 per cent nickel (based on 0.4 per cent nickel cut-off, 300 m below surface, December 1995) in four deposits. Over the life of the project a wide range of geophysical techniques have been used including airborne and ground magnetics, time domain clectromagnetics (EM), induced polarisation (IP)/resistivity, gravity and downhole techniques including EM, IP and physical property Measurements.

Jan 1, 1996

The provision of electrical power is an important consideration in project development. The first step to be taken in this area is to assess the power requirements of the project. The alternatives of laking a supply from a power authority or providing local generation can then be considered. This requires additional defmition of the probable characteristics of the supply.The availability of authority power in Australia is limited by the extent of the state power grids. Recent developments now allow these grids to be extended and their load capacity increased to meet major load increases at less cost than was previously possible.The options for local generation include diesel, gas turbine, steam, hydro, solar and wind, each having its particular performance characteristics and costs. The choice of fuel for diesel, gas turbine, and steam plant likewise involves consideration of a range of factors. The arrangements adopted for five recent Australian remote development projects indicate how some of these aspects influence the decision on power supply.

Jan 1, 1990

By Davey FJ

The Hikurangi Margin of eastern North Island New Zealand represents the feather edge of the over-riding Indo-Australian Plate at its convergent boundary with the subducting Pacific Plate. Towards the south, convergence becomes slower and increasingly oblique, and sediment supply from the Southern Alps becomes increasingly rapid. In this environment a 150 km wide, imbricate thrust, accretionary prism has grown since the Miocene, uplifting slope ridges and basins and a range of coastal hills. Offscraping of thick, axially transported, trench-fill turbidites begins in a zone of proto- thrusts, which extends up to 25 km beyond the principle, slope-toe, deformation front. On the slope, landward tilted, trench-slope basins are separated by ridges. The ridges ride up on thrusts that sole out at a major decollement. The decollement dips landwards at 3 degrees to a depth of 14 km at the coast, where it coincides with an onshore zone of high seismicity. Beneath the decollement, about 1 km of consolidated, oceanic sediment is going under the margin with the underlying oceanic basement. Some of these sediments may underplate the frontal ranges to the west and geochemical evidence of subducted sediment is found in the volcanic zone beyond. A rapid decrease in the width of the accretionary prism to the north is associated with a decrease in sediment supply and perhaps with a dislocation in the downgoing plate. To the south, the accretionary prism narrows, swings westward, and merges into the zone of very oblique collision that marks the transform between mirror image subduction to north and south of New Zealand.

Jan 1, 1987

Mine geologists have access to an economic mineral deposit, production parameters and secure exploitation title. They are well placed to understand ore formation and should contribute to the effective exploration of company mine property. Application of their special skills has been curbed by pre-occupation with production duties and by company re-engineering, including staff reductions. Contributions to exploration have been diminished and personal development inhibited. Modified management is required. Participation in mineral system studies and in exploration research comprise part of the basis for the re-emergence of mine geologists on the exploration scene. Changes in investment strategies in the minerals industry may create new employment opportunities. With regard to estimation of resources and reserves, the competence of practitioners who are incapable of disclosing their methods in transparent terms is under question. Ethical standards are also under public scrutiny because of some notable malpractice. Independent auditing may hecome more intrusive. While understandable in a market context, it reflects poorly on the profession. More substantial effort in public communications can improve the credihility ofthe industry and equip practising mine ceolouists for snider responsihility.

Jan 1, 1997

By Vilela A. C F

In the present work, the process of dephosphorisation of stainless steel was developed in laboratory scale by adopting a high frequence induction furnace, using BaCO3 base flux. By using BaCO3 - CaO - BaC12 - Fe2O3 Flux of about 110 g/Kg-metal, 30 per cent dephosphorisation degree was obtained a stainless steel containing 18,8 per cent Cr and carbon between 0,08 and 2,0 per cent. In addition, a dessulfurisation degree of 89 per cent was achieved too.

Jan 1, 1991

By P Hollings, J Holliday

Porphyry copper, gold and molybdenum deposits form in subduction-related settings in association with calc-alkalic or alkalic magmatism. Hydrothermal alteration assemblages are zoned, with potassic cores and propylitic haloes overlain by extensive domains of clay alteration and silicification (lithocaps). Copper sulfides, gold and molybdenite typically occur in veins or hydrothermal breccias, and less significantly as wall rock replacements. Epithermal deposits may form above or to the side of porphyry systems, and may be juxtaposed into the core of a porphyry deposit if rapid uplift and exhumation occur through the life of the magmatic-hydrothermal system. Volcanichydrothermal breccia pipes (ædiatremesÆ) commonly form late in the life of a porphyry system. They may contain clasts of porphyry-style mineralisation, and can host significant epithermal gold resources. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008