Search Documents

By B Davis, M Wallace, J Stewart, C F Burrett, J B. Cannell

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Sepon district in Lao PDR contains 1.8 Mt of JORC (2012) compliant contained Cu resources in addition to >4.5 Moz of Carlin-like Au in a Palaeozoic sedimentary package. The Cu deposits are proximal to an EW lineament of Permian rhyodacite porphyry (RDP) intrusive centres that are characterised by intense barren quartz stockworks. The Khanong deposit (42 Mt at 3.0 per cent Cu mineral inventory) is a carbonate replacement intermediate sulfidation deposit verging on a high sulfidation environment, where abundant pyrite, copper sulfides (chalcopyrite, bornite, trace enargite), copper sulfosalts (including tennantite – tetrahedrite, colusite), and base metal sulfides (sphalerite and galena) have replaced low dipping dolomite and limestone layers, forming a manto-style orebody fed by steep dipping intensely silica-pyrite altered structures. The Thengkham deposits (54 Mt at 1.5 per cent Cu) are composed of prograde skarns (garnet, clinopyroxene) and mineralised retrograde skarns (chlorite, magnetite, hematite, epidote, sericite, talc, serpentine, carbonates, sulfides) which are irregularly and semi-continuously distributed around an elongate 4 km long intrusive centre. Thengkham and Khanong have been strongly supergene enriched, forming secondary chalcocite breccias and exotic malachite zones.The Carlin-like Au deposits display a range of stratigraphic and structural controls and lie outboard of the Cu deposits. Similar structural controls, alteration assemblages and trace mineralogies suggest that gold and copper mineralisation are temporally and genetically related. It is hypothesised that the differences in style of Cu and Au deposits across the Sepon district are related primarily to palaeodepth and proximity to the intrusive centres.CITATION:Cannell, J B, Stewart, J, Williams, P, Wallace, M, Burrett, C F and Davis, B, 2015. The Sepon copper deposits (Laos) and their relation to Carlin-like gold mineralisation, in Proceedings PACRIM 2015 Congress, pp 399–408 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

The Gympie Goldfield was the sixth largest producer of gold in historic terms in Australia. The Joint Venture Agreement between BHP Gold Mines Limited and Devex Limited was signed in January 1987. Since that time, some $20 million have been spent on underground and surface exploration work in the southern portion of the goldfield. The project is of considerable interest as the dewatering, rehabilitation and equipping of an old rectangular timber-lined shaft has been undertaken. The project is located in Gympie, a city of 10,000 people. The issues of dealing with urbanisation and associated environmental aspects are vital to the success of the project. An outline of the project and the geology of the mineralised structures follows:

Jan 1, 1989

The metals titanium and zirconium and their alloys occupy individually unique positions in the catalogue of metallic materials available for engineering applications. Because of the uniqueness of their usage in the aerospace industry, in the case of titanium, and in the nuclear industry, in the case of zirconium, the except- ional resistance of both the metals to the majority of corrosive media is often overlooked. The cost factor in the application of these more exotic metals has, in the past, been a major considerat- ion in the rejection of titanium and zirconium as constructional materials in areas of usage where their superior corrosion resistance strongly favoured them over more conventional metals and alloys. The cost differential, vis-a-vis austenitic stainless steels, for example, is not a trifling matter, being of the order of 6 : 1, when compared on a weight basis. However, if one considers the cost, for, say, sheet product on an area basis, the ratio is redgced to approximately 3.4:1. If one also takes into account the enhanced performance of the more expensive material and the sub- sequent increase in service life and decrease in plant down-time, the economics of the usage of materials such as titanium becomes much more attractive and, indeed, highly competitive,

Jan 1, 1969

By Mez W

the German ruining industry uses different residues for hackfilling and stowing. A hydraulic pipe conveying technology for these materials has shown advantages for the transportation into the mine. Pipeline conveying systems are able to bridge long distances, they save room within the underground workings and they save staff and costs. Absolutely necessary for successful use of the hydraulic conveying technology is the knowledge about the unusual non-Newtonian flow properties of solid/liquid mixtures like pastes and slurries. The flow resistance of these materials cannot be described easily by one viscosity. Owing to a yield point and a pseudo-plastic behaviour the viscosity changes with the shear rate and with the streaming velocity inside the pipe. Also these flow behaviours depend very sensitively on the liquid/solid-ratio, often so dramatically that gravimetric or volumetric dosing equipment is not in a position to control the production of backfill pastes. Quality changes of the solid raw materials (particle size distribution, density, mineralogical composition) lead to additional difficulties. The first experiences with hydraulic backfilling plants were troubled by plugged pipes. a bad backfill quality caused by unnecessarily high water content and high costs for chemical binders to solidify the backfill. The installation of viscosity controlled paste production leads to success with the hydraulic backfill technology. A development of the l)MT, a bypass pipe-viscometer, has been the key technology. The system is able to analyse on-line, difficult, sticky and abrasive substances and determine their non-Newtonian flow properties. Because the system measures real physical values it is in a position to pre-calculate process relevant parameters like the pressure drop of the backfilling paste in the conveying pipeline. Newer types of the viscometer system also measure the slurry density and calculate its composition. These systems have proven a success controlling backfill paste production plants. They offer it secure prevention of pipeline plugging and a production of high quality backfill pastes with a water content as low as possible.

Jan 1, 1998

By Shatwell DO, Hayward SB, Leach TM

Following acquisition of the Woodlark Island tenement by Highlands Gold Limited, an exploration programme using extensive diamond drilling has confirmed that the style of gold mineralisation is similar to other SW Pacific Rim carbonate base metal gold systems. The two centres of gold mineralisation at Kulumadau and Boniavat-Busai are inferred to be related. to buried porphyry centres localised on NE trending major horst bounding structures. Individual prospects are localised on NW trending cross structures peripheral to the porphyry centres.Gold mineralisation has been derived from the mixing of hot saline magmatic fluids with cool dilute meteoric waters. While the bulk of mineralisation occurs in dilational tensional gash fractures, bonanza grades resulted from fluid quenching in feeder structures. Pre-mineralisation breccias created plumbing systems for hydrothermal fluids and similar paragenetic sequences are defined for Busai and the Kulumadau areas. These include early, distal porphyry, low sulphidation mineralisation, followed by base metal gold and carbonate deposition.

Jan 1, 1994

By T A. Short, P L. Brown

Kestrel Mine co-disposes around 1.5 Mt of fine (2SO4/t and to date around 9 Mt has been deposited. The mine plans to co-dispose of approximately 39 Mt of material, creating a dump with a maximum height of 35 m and a disturbance footprint of 260 ha. Benign materials suitable for rehabilitation are severely limited and no successful rehabilitation strategy has yet been demonstrated. A rigorous measurement and modelling program is resolving outstanding issues associated with acid rock drainage (ARD). The objective of the program is to develop and validate a strategy for dump rehabilitation that will control ARD and allow for mine closure. The strategy includes using a soil cover to reduce water flux into the dump to control the overall oxidation rate and to control effluent release. Monitoring of the oxygen distribution and water flux in the uncovered material commenced in February 2001 and monitoring in waste under a trial cover commenced in February 2002. Carbonaceous and sulfidic oxidation rates have been measured. Initial modelling indicates that the carbonaceous material has the general effect of slowing the rate of pyrite oxidation, lowering the maximum sulfate production rate and extending the time to oxidise all the sulfides. The combined approach of measurement and modelling provides a sound basis for assessing the performance of the trial cover and predicting the long-term quality and quantity of effluent at the base of the rehabilitated waste dump.

Jan 1, 2003

To finalise the arrangement and details of the headframe to be erected over the new No. 3 Shaft, the haulage and winding equipment requirements were first determined, then tentative designs were prepared to cover the needs of general shaft servicing work for men and materials, mullock and ore handling, and the probable requirements of a breaker station to be built adjacent to the headframe, which would provide for the crushing of the run-of-mine ore down to a size which would be suitable for feeding on to the concentrating mill.

Jan 1, 1957

By Chitombo G. P, Thompson A. G

Excavation engineering involves three key design processes; excavation design, blast design and reinforcement design. An excavation engineering methodology is proposed in an attempt to promote integration and simultaneous consideration of these three design processes. This methodology requires research and development of, inter alia, a universal rock mass classification system and a universal data display system. Simple examples are used to explain and illustrate the concepts central to these components in the three design processes.

Jan 1, 1995

The main features and recent developments in the processes of benefication and extractive treatments of tin ores are reviewed. The need for development of processes to recover fine tin, tin from low-grade complex ores and from hard rock resources is indicated. The progress in understanding of slag-metal interactions and developments of fuming processes on industrial scale is delineated. the processes and prospects of hydrometallurgical and chlorination methods are briefly indicated.

Jan 1, 1992

Supergene nickel sulphide ore mined currently by Agnew Mining Company is at times partially oxidised to sulphate. The resulting soluble nickel, and calcium and magnesium in mill water, are shown to act as depressants in flotation. The depressant effect is favourably selective in that violarite, the main nickel mineral, is less affected than pyrrhotite. Nickel recovery, however, is adversely affected, probably through reduced flotation of complex sulphides. Soda ash consumption is increased markedly by the presence of the cations as shown by operating data and pulp titration tests. A significant increase in concentrate grade, from 9% to 14% Ni, was achieved late in 1981. One of the changes in plant practice which contributed to this improvement was the addition of soda ash to mill feed rather than to flotation feed as before. It is shown by laboratory tests that this reduced the depressant effects of the cations, thereby improving recovery at the expense of rougher selectivity, or equivalently, increasing concentrate grade at constant recovery. The selective depressant effect cannot be exploited until scavenger recovery is improved and a scavenger concentrate regrind-retreat äcircuit is implemented. Development is

Jan 1, 1978

A model has been developed for the per iodical maintenance of bins used for hydraulic hoisting in mining of steeply inclining coal seams. This model gives a control plan for hoisting, bin switching and bin maintenance on a regular schedule.

Jan 1, 1977

The Yabulu refinery of Queensland Nickel Pty Lld near Townsville now imports more than three million wet tonnes per year of nickel laterite ore from New Caledonia and Indonesia, making it the largest importer of any commodity in Australia. The project has illustrated that importing untreated bulk ore and re-exporting high value products makes good economic sense for the company and the nation.The economics of this exercise were considerably enhanced in 1994 by changing the project's principal product from nickel-oxide sinter to refined high-purity nickel metal. It is one of the few operations in the world where nickel ore is transformed to nickel metal at a single site.Several novel technological processes were developed at Yabulu and incorporated into the refinery to allow this product transition to occur. By utilising internally developed technology the new processes were installed at a capital cost of less than $10 million. It is unique for a large nickel producer to change completely the quality of its entire product range many years after the plant was constructed and considerable attention to marketing the new products has been required.The changes have meant that the project is no longer limited to selling lower-value oxide sinter to a relatively small number of large stainless steel mills. In the past year sales of the new high purity nickel metal products have expanded to include a broad range of international customers in the special alloy, foundry and chemical industries.

Jan 1, 1995

By Griffiths L, Marshall P

fhis paper describes investigations into drainage of gas from the solid to control outbursts. Initial studies conducted on drainage of shear zones showed that, given enough time, these can be successfully drained. Once drained, they can be intersected and driven through without any activity of outbursts. The results of programme of investigations to determine parameters for drainage from the solid show that gas flow rates from the Bulli Seam on the average are about 2 litres/min/metre length of borehole. But when shear zones are intersected, the flow rates could be as high as 8 litres/min/ metre length of hole. Shear zones can be picked up from pressure measurements 50 - 60 m away and this could give sufficient time to drill through these zones and drain them in advance. Systematic drainage of Bulli Seam at West Cliff Colliery could eliminate or reduce frequency of outbursts considerably. At present drainage holes are being drilled systematically in the seam, with drainage installations on the surface. Gas purity of 80% methane is being delivered at the surface plant.

Jan 1, 1980

South Australia was founded as late as 1836, forty- eight years after New South Wales, yet within five years had announced the first discovery of metals in Australia. Throughout the 1840s the mining of silver-lead, then copper, spread north through the Mount Lofty and Flinders Ranges creating a thriving industry, years before the discovery of gold in the eastern colonies in 1851. The first significant mine was Kapunda (1842), followed by the much bigger Burra (1845) and other copper finds at Tungkillo, Worthing, Cal- lington, and North Rhine.

Jan 1, 1987

By Voss Smith F, Matters C. W, Slee R. T, Coldham JC, Davies HW, Wallman H. H

The Committee desires to thank the managers of the various mines along the line of lode for their hearty co-operation in its labours. It would also extend thanks to Messrs. J. O. Moulden, Howchin, Twelvetrees, and the West Australian Geological Survey for various information; to Messrs. J. G. Dreyer, S. Pope, T. Read, P. Moncrieff, R. Williams, and W. J. Rose for analyses; and to a number of local gentlemen for advice and help. Professor Skeats, of the Melbourne University, gave much valued assistance in petrology, and Mr. Herbert Lavers kindly undertook the study of the garnets.INTRODUCTIONThe famous Broken Hill lode is situated in a low range of hills, the Barrier Ranges, near the western border of New South Wales. It has been worked since 1884-first for, silver, then for silver and lead, and at present for lead, silver, and zinc. No excuse seems necessary for placing before members even an imperfect report on the geological features of this notable ore deposit, since so little work has been done on the subject as to constitute almost a national reproach. This is the more deplorablesince the evidence laid open by mining operations is destroyed almost as soon as it is exposed, and there exists the real need of a continuous and connected record of geologieal developments.

Jan 1, 1911

The exposed high face of Kerr's Quarry has dominated the township of Ferntree Gully for half a century. The near perpendicular face of bare dacite rock is a crumbling scar in an area of significant natural beauty. Apart from being unsightly, the face is a hazard for any person who approaches too close to its base or to the top edge. The height and the precipitous nature of this man made wall of rock is hazardous indeed. (fig. 1) The rock face is on the municipal boundary between the Shire of Sherbrooke and the City of Knox. This boundary was drawn when partition of the Shire of Ferntree Gully took place. There are many advantages in benching back the wall of the quarry but to do so the operation, located in Knox would need to extend into Sherbrooke. There are planning difficulties involved in such a manoeuvre, but during 1972, at a meeting of Cabinet Ministers, it was agreed that the matter be resolved.

Jan 1, 1976

In order to understand the technique, basic theoretical principles of radiation emission and in- strumentation theory are reviewed. Methods of surveying, reduction of data and interpretation are outlined. Other applications of the technique (e.g. in airborne geological mapping), as well as its specific use in uranium exploration, are discussed. By means of case history-type examples the successful applicant of gamma-ray spectrometry, as a tool in Australian mineral search, is demonstrated.

Jan 1, 1969

Commercial or potentially commercial deposits of coal occur in Australia in strata ranging in age from Permian to Tertiary. The coals of each period tend to show a community of petrographic character and significant differences as compared with coals of other ages. In particular- many of the Permian coals are unusually rich in inertinite whereas the Jurassic and Tertiary coals are typically very rich in vitrinite. The majority of the coals show evidence of deposition in environments subject to relatively minor marine influence. Except for some Tertiary and Permian coals the content of mineral matter tends to be high. Outcrops of coals of bituminous rank appear to be largely restricted to the eastern margin of the Australian continent. In this region vertical rank gradients are generally higher than in the other sedimentary basins and uplift and the removal of cover has occurred to a greater extent. To the west of the Tasman geosyncline, coal of bituminous rank generally occurs at considerable depths (usually in excess of 1 km and in some areas only at depths of over 2 kms), and in most areas coals at shallow depth are of sub-bituminous or brown coal rank. The controls of the distribution of coal type and rank have considerable economic significance and the unusual characteristics of Australian coals, especially with respect to coal type, make the direct application of overseas technology to Australian coals inappropriate.

Jan 1, 1975

Early theories of coal formation are outlined, with special emphasis on the arguments for allochthony and autochthony. Various aspects of the nature, growth, and decay of the characteristic vegetation of the brown coal peat moors, their conversion into coal, the origin of banding, and the influence of tectonics are discussed.A description of the banding in Victorian brown coals is followed by a discussion of their vitrain, fusain, and natural carbonized coal; and concludes with the nature of the coal resin and the possibilities of its extraction.The nature and derivation of inorganic matter in brown coal, based on Lessing's classification, is described. Assimilation of mineral substances in specific plants with variations due to environmental factorsare illustrated by analyses of present day trees. Consideration is then given to possible sources of salt, marcasite, and quartz in brown coal.It is shown that part of the inherent and extraneous ash may have been removed during and after coal formation. The nature and abundance of the organically combined substances in brown coal emphasizes the anomalies that may arise from estimating the total inorganic matter from ash contents.After classifying deposits on external heating surfaces of boilers, theoretical and practical aspects of slag formation, alkali matrix deposits, and the effect of sulphur and chlorine are considered.Analyses of deposits in boilers burning Victorian brown coal are tabulated.Slagging at the Yallourn power station from sand in the Yallourn open cut, and difficulties with Yallourn North Extension coal at the Maryvale paper mills are described.Tests carried out on Morwell and Yallourn coals showed that with the former, impacted deposits formed on boiler heating surfaces, and left a high percentage of chlorides on probes. Morwell briquettescompared with Yallourn briquettes also reduced the running time of a semi-industrial boiler through deposits with sodium sulphate as...

Jan 1, 1962

GENTLEMEN, I have to thank you very much for the honour you have conferred upon me by electing me President of the Institute for this year. On behalf of resident members, I have to offer the visitors a very cordial welcome to Mount Morgan, and to tell them that all arrangements have been made to enable them to inspect the mine and works at their own convenience, and to supply them with any particulars they may need.It is very pleasing indeed to see such a large gathering, especially on account of the long journeys many have undertaken in order to be present. The first congress in Queensland, about eleven years ago, was attended by a comparatively small number of members, and a rather long time has been allowed to pass in consequence. The large attendance at this meeting encourages the holding of meetings in Queensland more frequently. Owing to the long distances, and the number of mining centres in Australia and New Zealand, we cannot expect to meet oftener than once in six or seven years in...

Jan 1, 1911