Search Documents

By King D, Dickinson S. B, Matheson R. S

Commencing in 1956, Rio TInto Australian Exploration Pty Limited in association with Electrolytic Zinc Co of Australasia, Limited, has been carrying out a mineral prospecting program in North-West Tasmania over an area of about 4000 square miles.The program has comprised extensive airborne geophysical surveys, detailed geological mapping, ground geophysical and geochemical investigations. Out of the wealth of new data, and the examination of previous records, has emerged a new structural concept of regional ore control and distribution in North-West Tasmania. This roncept stems from the discovery of an ancient 'fossil' rift valley (graben), named the Owen Rift Valley, along which are located the major mines of the area and numerous well-known prospects. The known mines and prospects from north to south include Mt Bischoff (tin); the Pinnacles (zinc, lead, ropper); the Chester (pyrites); Rosebery-Hercules (lead, zinc, ropper, silver, gold); Mt Tyndall (lead, ropper, zinc); Comstock and Tasman (copper, lead, zinc); Mt Lyell (copper, pyrites, gold); Mt Jukes and Mt Darwin (ropper). The identification of the West Coast (Owen Conglomerate) Range as a fossil rift valley is due to Or B Campana, who carried out extensive geological mapping and interpretation work, and who, with S B Dickinson, are the senior authors of this paper.S B Dickinson, who introduced B Campana to the geological problems of West Tasmania, had previously investigated the Mt Lyell and Rosebery mining fIeld, to which reference is made in this work.D King assisted in the regional mapping and in providing numerous data on the mineral distribution of the area.R S Matheson rontributed to the fmdings on ore emplacement and rontrol in the discussions held on this subject. They are accordingly included as joint authors of this paper.Credit is also due to E McCarthy, who interpreted the geophysical results, and to J H Rattigan, who compiled the preliminary geological maps from published documents and by photo-geological methods.G Hall and V H Cottle, of the Electrolytic Zinc Co in Rosebery, provided invaluable geological data and suggestions in the course of the survey, and made a constructive criticism of the manuscript of this work. The airborne geophysical survey carried out by the Adastra-Hunting Geophysics Ltd company, furnished useful data which substantiated many of the fIndings on the stratigraphic and structural relationship. The Mines Department of Tasmania and S W Carey, Professor of Geology at the University of Tasmania, were instrumental in initiating the regional survey and provided the published and unpublished geological literature on the area.The authors also wish to acknowledge the invaluable assistance received from the Mt Lyell Mining and Railway Co in Queenstown, which made available the more recent geological and mining documents rompiled by M L Wade and M Solomon.

Jan 1, 1994

By Lloyd F, Bayley F. J

The new South Mine in the Western Deep Levels complex is destined to become an ultra deep project extending to depths of 4 200 m below surface and where rock temperatures are likely to exceed 65 ¦C. Initial estimates put refrigeration requirements at 133 000 kWR. A surface refrigeration plant with an initial capacity of 42 000 kWR has been commissioned and will be used for mining the upper levels.

Jan 1, 1988

Introduction.History of Stope Filling at Mount Isa.The Need for a Systematic Fill Programme.Reasons for Filling.Fill Materials and Tonnages.Rough Mullock Fill.Quantities Readily Available.Fill Pass Development.Stope Preparation.Drainage.Hydraulic Sand Fill.Initial Experiments with Mill Tailings.Surface Layout.Operation Procedure.Underground Pipe Lines.Life of Sand Pipes and Cones.Drainage.Old Tailings Dam Sands.Quantity of Fill Placed.Pillar Tonnages.Conclusion and Acknowledgment.INTRODUCTIONFilling practice outlined in this paper refers exclusively to the Black Star section of the mine. The stope filling necessary early in the life of the Black Rock and portions of the Rio Grande sections is not to be confused with the current filling programme.

Jan 1, 1953

By N Currey, G W. Wilson, P Ritchie

Kidston Gold Mine in Queensland, Australia has a 310 ha tailings impoundment that has undergone final closure rehabilitation. Kidston Gold Mine evaluated their closure options for this low acid generating tailings impoundment, and due to a lack of cover soils and the cost of importing material, the mine decided to investigate the possibility of direct vegetation onto the tailings impoundment surface. The mine subsequently embarked upon a well planned and detailed research program to determine the feasibility and sustainability of this closure option. The research program included vegetation trials, toxicology studies for metal uptake by vegetation, as well as a comprehensive closure water balance model for the tailings impoundment complex. This paper describes the results of the long-term closure water balance for the tailings impoundment complex for the pre-closure state of the impoundment, as well as predictions towards the impoundment performance once final rehabilitation of the tailings impoundment complex has been achieved. The water balance presented is unique in that it is founded on unsaturated flow principles and accounts in full the impacts of the surface flux boundary conditions. This novel approach enables the prediction of actual infiltration rates into the tailings impoundment surface, which in turn allows for the calculation of how much seepage will exit from the tailings dam toe drains.

Jan 1, 2003

By Clift N

Lead concentrate from the Isa and Hilton lead-zinc concentrators of Mount lsa Mines Limited is smelted at Mount Isa to produce a lead-silver bullion. This bullion is cast into four tonne blocks and shipped to Britannia Refined Metals Co Ltd, NorthDeet, England and to plants in Asia for refining and marketing. The traditional treatment stages at Mount lsa are sintering, smelting, and drossing and casting, with some of the sinter plant feed being pre-treated through an Isasmelt plant.A commercial scale lsasmelt based lead smelter was commissioned in early 1991.

Jan 1, 1993

By Hatherly P, Holt GE, McNally G

The current methodology for delineating and subsequently evaluating coal reserves is based on the use of vertical drill holes and surface based geophysics/geology. These techniques have three major problems, these being respectively:-a) Vertical drill holes can only provide a small sample of the coal seam and stratigraphy. Therefore the planar variation in coal reserve and environment parameters can only be approximated.b) Although surface based geophysics has had its fair share of success in recent years, there are still environments which have masked the finding of major structures.c) Access to drill sites is difficult at some locations due to mountaineous terrain, standing water and environmental impact.

Jan 1, 1985

The Kangiara mine is located within the Middle to Upper Silurian Hawkins Volcanics of the Douro Group near Yass, New South Wales. The deposit is a po1ymetallic type within a rhyolitic tuff.The ore minerals comprise pyrite, sphalerite, botryoidal sphalerite, galena, chalcopyrite, marcasite, tetrahedrite, bismuthinite, bismuth, silver, electrum, chalcocite, covellite, and digenite. The gangue minerals are quartz, barite, calcite, and the host rock. Locally sericite occurs.Several distinct ore types can be recognized, mainly on the basis of their macroscopic textural appearance, and it is inferred from these general features that the mineralization had a submarine volcanic-sedimentary origin similar to that of the Kuroko deposits in Japan.

Jan 1, 1976

The Woodlawn base metal sulphide deposit, located 50km S of Goulbum, New South Wales, was mined as an open pit operation for 10 years from 1977, producing 8 million tonnes of ore. Underground development began in 1985 and reached full production of 500,000t/yr as open pit mining ceased in mid 1987. Underground development highlighted the extensive deformation and intense alteration associated with the deposit and the host rocks.The deposit occurs above an acid volcanic pile in a sequence of interbedded and interfingering shales, cherts, volcanogenic sediments and pyroclastics of mid to late Silurian age intruded by dolerite sills.

Jan 1, 1990

In the first half of 1987 two four metre diameter raise bore holes were drilled at the Olympic Dam Project for ventilation purposes. The first hole, 476 m x 4.0 m diameter was completed in 96 days, 35 days longer than scheduled. The second hole, 407 m x 4.0 m diameter was completed in 39 days, 2 days ahead of schedule. Both holes were drilled with a Robbins 121R rig using a Wirth head that consisted of 23 face cutters and 5 side cutters, supplied by a contractor. After the sites were located a grouting program was carried out to help seal off an aquifer between 160 and 180 m below the surface. Cavities discovered in the Andamooka Limestone were filled with concrete. Because of the overlying dune sands and clay both sites were pre-sunk to the competent Andamooka Limestone.

Jan 1, 1988

By Gray N. B

The need to improve existing metallurgical processes and to develop new processes to meet the economic challenges that lie ahead requires the application of the tools of process analysis viz. mathematical models, physical models, pilot plants, laboratory measurements and plant tests. Examples of the application of these techniques to processes are described in this paper. Several of these techniques, combined with basic knowledge, are necessary to make improvements and for existing processes this always involves plant measurements. Also because metallurgical processes include extraction, refining, alloying, casting, mechanical working and heat treatment, an interdisciplinary approach to research and development is essential. This paper argues that metallurgical engineering is a discipline that is uniquely able to encompass the broad spectrum of chemical- and physical-metallurgy processes and is therefore essential to the health of the metallurgical industry.Regrettably many metallurgical engineering departments are not offering courses on process analysis, control, optimization, etc so necessary to meet modern industrial challenges.

Jan 1, 1985

Industrial and telecommunications organizations around the world are now turning to optical fibres to satisfy their growing needs for data, voice and video communications and to solve transmission problems in noisy and hazardous environments. Already, coaxial cables have been made obsolete for intermediate and long distance applications and fibres are making in-roads on other copper cable and microwave system techniques.The idea of optical fibres is not new, but techniques to manufacture the high quality cable and components required have only recently been developed. Nonetheless, the technology is now advanced, reliable and mature, and costs are plummeting with increased production and market competition.The mining industry has benefited greatly from developments in electronics and communications over the years. Optical fibres are to have a further significant impact and the time is now right for the industry to begin to exploit the many advantages of this new medium. Applications include data transmission, long distance telecommunications, measurement and control systems, surveillance, computer networks, etc.This paper briefly describes the characteristics of optical fibres, current status of the technology, applications and possibilities for future development.

Jan 1, 1984

By Kubo H, Ninomiya R, Ojiro T, Sato T

New high-strength Zn alloys for moulds are demanded from the automobile and electric industries in Japan, because the s rength of Zn moulds is still not high enough for the mass production. There are two approaches to improve the strength of Zn alloys. One is to increase the Al content. ZA alloys (ZA-8, ZA-12, ZA-27) were developed through this approach. The other is to increase the Cu content. But it is known that an increase in Cu generally depresses the castability of Zn alloys, so that the alloys with increased Cu have been rarely studied until now. In this study a reconciliation between the strengthening and the castability of Zn alloys by enriching both with Al and Cu has been attempted. Accordingly we have studied on the Zn alloys containing 4 to 25 mass per cent Al and to 24 mass per cent Cu have been studied. Their fluidity, which primarily corresponds to the castability of the alloy, were measured first and 19 alloys were selected based upon their fluidities and casting temperatures. Mainly the mechanical properties of all 19 alloys were tested and some were found to be excellent in both strength and castability. Z1009 (Zn-IOAI-9Cu-0.02Mg alloy) cast in a sand mould has the tensile strength of 360 MPa while ZAS (Zn-4AI-3Cu-0.04Mg alloy), which is the most popular alloy for moulds, is 215 MPa. Z2520 (Zn-25AI-20Cu-0.02Mg alloy) cast in a sand mould has a Vickers hardness of 178, compared to 107 for ZAS and 104 for ZA-27 (Zn-27AI-2Cu-0.02Mg). Furthermore the castability of Z1009 is as good as that of ZAS. The underside shrinkage occuring in casting ZA-27 is restrained in Z2520.

Jan 1, 1993

By Hulton SJ, MacKenzie DH

The Broken Hill orebody within the leases of ZC Mines is still a major lead-silver-zinc resource after over 80 years of mining. It illustrates particular problems encountered in resource and reserve estimation in old mines. The six mined ore lenses are characterised by three features: ò complex external geometry, ò high internal grade variability, ò bimodal grade distribution. The high grade 3, 2 and 1 lenses and B lode have sharp external contacts but contain some low grade internal zones. By contrast A lode is of lower average grade and comprises an extensive but geometrically variable mineralised zone within which are numerous irregular bodies of high and medium grade ore. Geological factors are the main source of variability in reserve estimation, which historically has been conservative. For many years the geological resource tonnage has been maintained at a level sufficient to make up for extraction but at a gradually declining grade. Using a geological block cut off grade of 10% Pb + Zn the present in situ resource is 53.8 Mt grading 8% lead and 13% zinc. Using empirical cut factors a "recoverable reserve" is derived from this large geological tonnage. There is some doubt that the "recoverable reserve" is conservative enough to reflect mining reality. The most sensitive indicator of forthcoming change in total resource or insufficient drilling and development is given by changes in the tonnage and grade of possible ore from which the proved and probable categories are derived. Examples are given to show that where reserves are drill indicated, the delineation required for proved ore reserves must be enhanced to achieve final stope design. The move in recent years to greater emphasis on non entry mining and lower recovery of in situ material poses a dilemma for a mine which has practised 100% recovery for much of its past. The need for a realistic reserve assessment in current terms needs to be balanced against the fullest possible geological knowledge of the resource to cater for future technological developments.

Jan 1, 1987

By McDougall I, Claoue-Long J

A combination of high precision 40Ar/39Ar and U-Pb dating has been used to determine the age of hydrothermal minerals and host rocks in a number of Lachlan Fold Belt (LFB) gold deposits in New South Wales, Au4 ralii In particular, this investigation demonstrates that the UAr/ Ar technique of K-Ar dating can be used to determine the timing of mineralization in Palaeozoic systems.A close temporal link between mineralization and Late Ordovician to Early Silurian magmatism is indicated by the dating work. Hydrothermal sericite from the Goonumbla p8rph gy Cu deposit and Glendale Au prospect yieldsAt/ Ar step heating ages between 437.9 ¦ 1.1 and 441.2 ¦ 1.1 Ma (16), and4 minjrnum age of about 425 Ma has been obtained by Ar/ Ar dating of hydrothermal amphibole from the Browns Creek Au-Cu skarn deposit. Hydrothermal aluniI8 frog the Gidginbung epithermal Au deposit yields reset 44 Ar/ Ar ages of 401.0 ¦ 1.3 to 417.3 ¦ 1.3 Ma (16). U-Pb dating by ion microprobe on magmatic zircons from the vicinity of the Goonumbla and Gidginbung deposits gives ages of 438 ¦ 3.5 Ma (2 6), and 435 ¦ 2.5 Ma (2 (7) respectimly, W a minimum age of 435 Ma has been obtained by Ar/ Ar dating of magmatic phases from volcanic rocks adjacent to the Browns Creek skarn deposit. Magmatic episodes near the Sheahan-Grants gold skarnpost give ages of 479.2 ¦ 1.1 and 467.9 ¦ 4o1 by 'Ar/ 9Ar dating of magmatic amphibole. Most Ar/3yAr age spectra show the effects of partial Ar loss at between 360-420 Ma, probably due to heating caused by granitoid emplacement.The radiometric dating work in this paper suggests a restricted metallogenic epoch in the Late Ordovician-Early Silurian LFB, NSW, of similar duration to that found in the Andean margin and the western Pacific island arcs around the Pacific Rini.

Jan 1, 1990

WINDING engines are one of the most important units in the equipment of a mine. Upon the winding machinery depends not only the output of the mine, but it supplies in most cases the only means by which workmen enter and return from the mine, and consequently the utmost care and attention is desirable in its design. The efficiency of a direct acting winding engine, as a machine is very low. In other words, the proportion between the useful work performed and the actual work the engine is capable of performing (under the most favourable conditions) is very small. The reasons for this are:-1. The intermittent nature of the work; the engine is stopped from 20 to 25 %(or even more) of the time which would constitute a useful day's work.2. The large amount of power that is absorbed applying the brakes to bring the load to rest.3. That the net useful load raised is small in comparison with dead load to be lifted, and the parts to be set in motion.4. That, owing to the frequent stops, initial condensation in the cylinders is always greater than in a continuously running engine, whilst radiation from steam pipes, valve chests, &c., goes on whether the engine is running or...

Jan 1, 1911

Both as an energy source and as a raw material, natural gas is playing an increasingly important role as a catalyst for the development, continuation and rebirth of mining projects in Australia. Pipelines are the vital link in making natural gas available to a region and to individual mines. This paper will cover the role of pipelines in supplying mining projects in Australia, the development and status of the Ballera to Mount Isa gas pipeline and the future prospects for gas pipelines in the Carpentaria Mineral Province.

Jan 1, 1998

Longwall mining in Australia is approaching maturity. Longwall production from 'state of the art' Australian longwall mines now rivals similar US based longwall operations. Regrettably however, Australian gate road development rates in general fall short of the required development to longwall production ratios that are required to sustain annual longwall production capabilities. By contrast, most US based longwall mines achieve the required development to longwall production ratios to sustain their longwalls. This is despite many having to drive three heading longwall panel gate headings to meet regulatory requirements.

Jan 1, 1998

By Smith S. F, Terezopoulos N. G

This paper discusses experimental results of physical scale models employed to study the stability of a pillar between rectangular roadways. A programme of laboratory investigations utilising a bi-axial test rig has been undertaken to examine the influence of various stressfields on the stability of pillars between mine roadways. The effect of pillar height/width ratio on the overall stability is studied. Observations of failure characteristics in and around pillars are discussed especially in relation to the various stressfields applied to the models.

Jan 1, 1992

By A Jurg, F Leclercq

The total drill and blast concept is widely known in the mining industry. On the contrary, the quarry industry rarely adopts such working methods. Based on the experience of the CBS quarry in the North of France, this paper shows how up-to-date blasting technology and simple control methods can significantly improve the overall Mine to Mill efficiency of a quarry. The CBS quarry, in partnership with the EPC group and Nitro- Bickford Company, adopted a new working process three years ago aimed at increasing blast performance and related productivity of the downstream process (loading, hauling and crushing). The pattern geometry of each blast is controlled and explosive charging is carried out following the æconstant specific energyÆ CSE concept. This method provides a homogeneous fragmentation distribution and reduces vibration peak-particle-velocities. The impact on downstream productivity is controlled by means of a simple information management system, which collects and measures key parameters of the production process such as; hauling cycles, crusher throughput, secondary breaking and vibration peak particle velocity. This information system has clearly proved over time that consistent blast quality could be achieved, leading to a 30 per cent improvement in quarry productivity. Improved energy control of blasting through optimisation with electronic detonators, allowed a significant reduction in vibration impact on the environment. Improvement in blasting security, reduction in the environmental impact and productivity enhancement are major benefits that quarries can obtain from these CSE optimisation blasting methods.

Jan 1, 2007

By OÆBrien D. R

Up until June 1988, Mount Thorley Coal Handling and Preparation Plant disposed of tailings by two methods. Approximately half of the plant tailings was mechanically dewatered by solid bowl centrifuges mixed with plant reject and was subsequently disposed in mine overburden spoils; the remainder was pumped to tailings ponds. Both future mine planning and environmental constraints could not allow for the long term construction of more tailings ponds so, following evaluation of available dewatering technology, belt press filters were selected for the treatment of tailings in excess of the capacity of the existing solid bowl centrifuges. Commission of the four 2.5 metre wide belt press filters soon showed that marked differences in performance were experienced when treating different coal seams. Further analysis showed that the coal tailings from different seams were quite different in terms of clay mineralogy, and these differences could be correlated with varying degrees of filter performance. Poor filter performance was experienced with coal tailings rich in sodium montmorillinite clays. A number of variables were investigated including in-line mechanical mixing of flocculant and feed slurry, cation exchange reagents such as gypsum, and upstream addition of cationic flocculant. In order to achieve satisfactory performance on the worst tailings, a combination of all of the above was required. In this paper, the reasons for selection of belt press filters and the program of investigations and testwork required to arrive at satisfactory belt press filter performance for the treatment of troublesome bentonitic rich tailings are discussed.

Jan 1, 1989