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By Arnold J. J

The design of a coal preparation plant using bore core data cannot be discussed without some reference to the wider considerations of design. A thorough knowledge of coal preparation processes and processors as well as ancillary equipment is essential if the coal properties determined from bore cores, are to be fully utilised. Whilst generalised information of processes is available from a wide range of publications and equipment suppliers for the intending plant designer, local operational experience must be taken into account where there are similarities. However it would be wrong to assume that satisfactory plant design can be achieved merely be repeating previous design parameters. A detailed examination of bore cores used in conjunction with well proven design 'criteria will identify important differences in design parameters without which efficient and economic plant/sectional sizing cannot be achieved.

Jan 1, 1977

By M Pizey, P Lindsay

Coal mining has been occurring on the Stockton Plateau for over 100 years. As a result of both natural conditions and mining activities, surface water on the plateau is known to have low pH and elevated metals concentrations, a condition known as acid rock drainage (ARD). Solid Energy New Zealand Ltd (SENZ), as owners of the current mining operations at Stockton desire to understand the nature and causes of ARD at Stockton to determine whether commercially viable options can be developed to improve the water quality to levels acceptable to the local community and regulators. A series of integrated water quality investigations have been performed towards developing a characterisation of the water quality on the Stockton Plateau and receiving waters. The investigations performed include: design and implementation of a water quality monitoring program to collect a satisfactory base of water quality data from which to develop an understanding of the water quality and its variability, and to collect data regarding the range of flow rates that occur in the principal streams; development of a hydrological model for the Plateau with the ability to predict flow rates at key locations on the plateau and on the Ngakawau River; field investigations of the bio-diversity of the plateau and surrounding areas, to develop a snapshot of the health of aquatic communities and whether streams draining mine workings are æadversely impactedÆ; eco-toxicology; waste dump seepage water quality monitoring at selected basal springs, drilling, investigations and permeability and geochemical testing; data processing of a range of historical data and the newly acquired data for the development of empirical relationships that describe the water chemistry system and its relationship in turn to flow rates in the streams; simulation of the long term water quality record for the measured parameters (pH, acidity and metals concentrations), based on the hydrological model and the empirical relationships developed from the new database; and preliminary development and examination of mitigation options for the ARD issues at the mine. The study has progressed towards design of pilot studies of options for mitigation of the generation of the ARD as well as treatment of the discharges. It is the integrated approach adopted by SENZ from an early time in the investigations, that has enabled fast-tracking of the pilot engineering trials. This paper presents the results of the field investigations and eco-toxicology studies and demonstrates the value of predictive modelling of water quality in the study area, even at a very early stage in the remedial engineering design process.

Jan 1, 2003

By Duncan B

Shortwall continuous mining as first introduced at Burwood colliery, and currently being used at John Darling, Lambton, and Corrimal collieries, is a method of coal winning which was pioneered in the Newcastle district. The system uses individual hydraulic self-advancing chocks for roof support and the coal winning operation is by continuous miners and shuttle cars. Where physical conditions are suitable the system provides a safe, efficient and economically viable basis for pillar extraction. Shortwall operations have been conducted successfully in the Victoria and Dudley seam, near the coastal fringe of the Newcastle district and are now being tried out in the more difficult conditions of the Bulli seam in the Illawarra district.

Jan 1, 1972

By Fabjanczyk MW, Guy RJ, Tarrant GC

The design of the reinforcement systems required to stabilise mine roadways has developed through the application of field measurement techniques. These techniques have allowed the level of security of a given opening to be determined from an assessment of the loading within the reinforcement, the extent of roof deformation and experience. The design systems developed are now used extensively in a wide variety of geological environment. Recent interpretative techniques have been developed to improve the level of confidence when designing roadway reinforcement. The techniques are particularly applicable for roadways subject to either weak materials or extreme stress levels. A second area of application is where roadway advance rates and hence the timing of reinforcement placement are critical. The newly developed techniques include both analytical and computational models. The validated computational techniques allow a more rational approach to investigation of the effect of varying reinforcement type, timing of placement and density on the level of stability achieved.

Jan 1, 1992

The comminution process indicates that the most energy-efficient comminution system would be one where the particles leave the breakage field as soon as they reach product size. Contrary to the free falling gravitational (vertical) flow in crushers, the grinding millÆs energy efficiency essentially depends on ore characteristics and the discharge rate of broken particles, which in turn depends on how efficiently the discharge pump (grate and pulp lifters) operates. The essential function of a pulp lifter is to transport the broken material and slurry from the discharge grate out of the mill. Hence, the design optimisation of pulp lifters affects not only the energy efficiency and throughput of autogenous grinding/semi-autogenous (AG/SAG) grinding mills, but also contributes other process benefits such as improved wear life and operator-friendly steady and smooth mill operation. Following its introduction in 2006, OutotecÆs patented Turbo Pulp Lifter (TPLÖ) design has been retrofitted at existing sites and also installed in some new ones around the world. This paper will provide operational experience and data on how the TPLÖ design has allowed AG and SAG mills to operate efficiently.

Jan 1, 2009

By Chappel R. A, Fishburn B. R

The Eastern Distributor Tunnels - the first major road tunnel project in Australia - are the preferred solution to traffic congestion problems, when compared with alternatives, in this inner urban environment. This is because of the reduced impact on residential housing, the improvement of the existing environment, less restrictions on future developments, and a reduction in noise and pollution. Developments leading to a tunnelled solution, traffic needs and reasons for route location are discussed. Criteria for design of tunnel alignments and geometry are described, including the restraints imposed by surface connections on profiles and grades resulting in low rock cover at tunnel portals. The main geotechnical restraints are a major weathered dyke at the shallow large span underground fork and the weathered Ashfield Shale capping the Hawkesbury Sandstone at a portal. Rock cuttability and excavation methods are discussed. Roadheader machines are the most suitable for the varying shallow arched cross sections required and the tunnel lengths involved but the use of blasting in special situations cannot be ruled out. Initial support for the major tunnel lengths will be provided by rock reinforcement in conjunction with shotcrete. Steel ribs are proposed in areas of low cover and weak ground. Final support will comprise an insitu concrete lining. Construction concepts and special tunnelling methods required at the shallow underground forks and tunnels are described.

Jan 1, 1987

By Botz R. W

Macroscopic and microscopic studies of the outburst-prone Gemini Coal (Bowen Basin) showed that outbursts were associated with a localized inertinite-rich ply. Previous studies of the Gemini Coal had shown a general relationship between desorption rate, regarded as a good measure of outburst proneness, and inertinite content of coal samples.Desorption rates increased with increasing inertinite content and were highest for inertodetrinite-rich samples. These results suggest that inertinite content and composition play a significant role in outbursting and may be useful in identifying outburst-prone coals, which could be confirmed by desorption measurements.Consequently outburst-prone areas in the Upper Permian coal measures ofthe Sydney, Gunnedah and Bowen Basins have been defined using a combination ofthe parameters, inertinite content, depth ofcover and coal rank. In the Upper Permian, inertinite-rich coals are confined mainly to the top of the coal measures, except in the Sydney and Gunnedah Basins where an inertinite-rich interval (Bayswater Coal and correlatives) is also present towards the base of these measures. Only a small area ofthe central Sydney Basin, butmuch ofthe north-eastern and north-central part of the exposed Bowen Basin is considered outburst prone on the basis of these parameters.The most outburst-prone inertodetrinite-rich lithologies have a patchy and unpredictable distribution in the top of the Upper Permian coal measures. They can be defined only by sampling and petrographic analysis at the subsection level.

Jan 1, 1986

By Smith JW

Studies of 13C/12C ratios of carbon dioxide in seam gases and in secondary calcites show that 1. In mines prone to carbon dioxide outbursting, the source of this gas is external to the coal. 2. Faults draining reservoirs of magmatic or primary carbon dioxide, rather than intrusives, are the most likely points of entry of carbon dioxide into mines. 3. The higher the concentration of carbon dioxide in seam gas and the wetter the mine, the lower the likelihood of secondary calcite occurring as a filling in cleats, fractures etc. 4. A -role played by carbon dioxide in promoting outbursting may be the conversion of calcite to soluble bicarbonate, the removal of this in mine water and the subsequent weakening of the resistance of the bulk coal to stress.

Jan 1, 1980

Heavy media separation serves to upgrade mill feed and reduce unit operating costs, allowing ores to be mined which could other wise be uneconomic. At the Aberfoyle mine at Rossarden in north-east Tasmania, a simple heavy media operation using a converted Akins screw classifier as a separating vessel, removes barren quartz from mineralised material. At the Cleveland mine at Luina on the west coast of Tasmania a more complex ore mix requires a versatile operation combining hydro-dynamic and static separation equipment to provide an efficient beneficiation circuit. The two operations are briefly described with a background of basic heavy media separ- ation practice.

Jan 1, 1978

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

By Valenta R. K

Copper-gold deposits associated with iron oxide rich rocks (ironstones) form a distinctive and significant ore association which occurs widely, but not exclusively, in the Proterozoic. The ironstone association is geochemically distinct from the BIF-hosted gold association (Phillips and Groves, 1983). Not only is the former association higher in its copper and commonly uranium, FEE, ¦bismuth, molybdenum contents, but also the ironstones in many cases do not originate as chemical sediments. Although both associations form in metamorphic environs, they reflect differing tectonostratigraphic settings and with consequent differences in ore-forming fluids and ore-forming mechanisms. This paper discusses the nature and origin of the ironstone-related copper-gold association, with particular reference to the Tennant Creek district in northern Australia, and emphasises the two stage origin of mineralisation. The genetic model developed has significant implications for other ore-bearing environments.

Jan 1, 1990

By Simmons SF, Fleming J

Alteration and mineralisation at the Island Copper deposit is related to the intrusion of Early Jurassic quartz feldspar porphyry dykes into surrounding comagmatic Bonanza volcanic rocks. The pyrophyllite alteration zone forms an upward flaring cone, largely hosted within a breccia body that c ross-cuts the Cu, Mo, and Au-rich ore shell. This alteration zone contains pyrophyllite, dumortierite and diaspore and resembles alteration occurring in some high-sulfidation deposits, but which is barren. Fluid mineral equilibria and fluid inclusion studies indicate formation at approximately 300 ¦C from fluids dominated by steam and gases. These fluids appear highly acidic, but sulfur poor, leading to extreme base leaching within the breccia body and surrounding rocks.

Jan 1, 1995

The Permian rocks at Gympie were first studied as far back as 1868 in conjunction with the discovery of gold. The relationship of the Gympie Group to other sequences in the Gympie Composite Terrane is an important subject of investigations in a new mapping project of the Geological Survey Program of the Department of Resource Industries.In two areas the Gympie Group has been divided into four defined formations. They are the Highbury Volcanics (base), Ram mutt Formation, South Curra Limestone and Tamaree Formation (top) in the Gympie area, and the Mant basalt (base), Kolbar Formation, Gigoomgan Limestone and Teebar Formation (top) in the Gigoomgan area. Geochemical and lithological evidence from the basal volcanics of the Gympie Group (Highbury Volcanics, Mant basalt) indicate that they developed in an intraoceanic island arc setting. The overlying volcaniclastic sediments (Rammutt Formation, Kolbar Formation), which contain some continentally-derived material, are mainly of local derivation and shallow-water marine. A hiatus is present at the top of the Early Permian Rammutt Formation and Kolbar Formation. Following the hiatus, limestone sedimentation characteristic of a basin of restricted circulation developed in the Late Permian. There is some evidence of a hiatus between the limestone deposition of the Gigoomgan and South Curra Limestones and the overlying probable turbidite deposits of the Teebar and Tamaree Pnrmatinnc

Jan 1, 1990

By P Waters

BHP Billiton Iron Ore initiated a program in January 1995 at the Mt Whaleback operation in Newman, Western Australia to develop a closure plan for the overburden storage areas (OSA), which have the potential to generate acid rock drainage. The primary research program includes the development of technology for the long-term performance of OSAs with respect to slope stability, surface run-off, erosion, water infiltration and vegetation. The objective is to control acid rock drainage by preventing moisture movement into and through the OSA material. Infiltration to the underlying OSA material and closure costs are minimised due to the presence of the run-of-mine (ROM) cover material. A summary of the field data is presented to illustrate low percolation rates to the underlying OSA and key performance characteristics of the moisture store and release cover system design. Field data collected to date demonstrates that a moisture store and release cover system constructed with suitable ROM material has good potential as a final cover system at the Mt Whaleback site. The performance of the cover system on a sloped surface was significantly different as compared to placing the cover system on a horizontal surface.

Jan 1, 2003

By Durucan S

The southern Attiki peninsula is a very interesting area from an environmental point of view. The port and the city of Lavrio is situated at the east coast of the peninsula with about 10 000 inhabitants and there are also a few villages in the vicinity. The south-eastern part of the peninsula hosts the famous Lavrio mines which exploited the silver bearing orebodies of the area for more than 25 centuries. As a result, soils around the city of Lavrio are polluted with high heavy metal loads. The area is also of archaeological interest, as there are well preserved remnants of ancient mining and processing plants and archaeological sites. Soil samples collected from an area of approximately 120 km2 around Lavrio were analysed for their metal contents and the spatial distribution of the concentrations of ten selected elements were estimated from these data sets. The spatial data analysis and transformation capabilities of Geographic Information Systems, combined with extensive mining and geological data, helped the authors to identify the extent and causes of metal pollution around Lavrio.

Jan 1, 1995

Cominco Ltd's Polaris Mine in Canada's High Arctic has been successfully mining zinc ore in permafrost since 1981. Mining methods using frozen backfill have been the key to success. The mine is now producing about 60 per cent of the ore from pillars while maintaining high productivities. Annual ore production is just over one million tonnes providing more than 200 000 tonnes of zinc concentrate each year. Cominco Ltd has adapted management and operating practices to suit the harsh environment and the isolated site, and has shown that a profitable development can be carried out in the tough Arctic conditions, with minimum impact on the environment.

Jan 1, 1993

By McClarnon D. J

This paper aims to provide the reader with an insight into the field of computer graphics and Virtual Reality (VR), and show how both have been applied to the general area of Free Steered Vehicle (FSV) operations underground. It first explains this developing computer technology and explains its advantages over existing CAD based solutions. This paper deals with the graphical applications and implications of building models within a computer's memory. It then continues to describe the problems with Free Steered Vehicle operations. The work already carried out in the field of VR is explained, and the production of a VR system addressing the problems with fitting cameras to aid the driver's field of view is detailed. Another possible use of VR is also explained - the concept of risk regions, demonstrating its uses in the examination of proposed operational methods. Examples of possible uses are given, and its potential advantages over existing methods discussed. A case study of a computer-generated video involved with the safety of operations of FSVs is also presented. This addresses the precautions that pedestrians should take to ensure safe working in areas where FSVs are operating. This paper then concludes with possible further applications for computer graphics and VR, and the on-going research into these two technologies.

Jan 1, 1995

By Spencer GA, Saul SJ

The flight line spacing in low level aeromagnetic surveys is the principal factor governing both the cost and the amount of geological detail which can be extracted from the data. The rate at which geological resolution diminishes with wider line spacing is illustrated by progressive subsampling of a 200 m spaced data set from the Charters Towers region in Queensland.The usefulness of high frequency type filters in enhancing shallow structural features is seen to be limited to the 200 m data.It is concluded that each data set is suited to a particular scale and style of geological investigation with only the 200 m data having sufficient detail to identify the subtle structural patterns which are crucial to mineral exploration.

Jan 1, 1976

By Jay W. H, Brown L. J

Several case studies are examined in which analysis of treated ores and extracted metal species by Mossbauer spectroscopy provides information not available by other competing techniques. The cases include poorly crystalline, surface iron oxides in titanium minerals and chalcopyrite, gold in ores and bacterially oxidised ores and the adsorbed species from gold extracted from cyanide and chloride solutions onto activated carbon and polyurethane foams. Some limitations on the use of the technique in terms of sample size, sensitivity and counting time are also discussed.

Jan 1, 1997

Particles finer than 10 um often cause problems in flotation. The current under- standing of the nature of the following effects is discussed: slime coatings on particles, carrier flotation, increased froth stability, entrainment of ultrafine gangue, excess reagent consumption, slower rate of flotation, more reactive surfaces. The review emphasizes the principles underlying these effects rather than details of progress in practical solutions to the problems they cause. The princi- ples of selective flocculation and floc flotation and the various approaches to achieving selectivity are discussed. Hydrodynamic effects on floc growth are reviewed. The evidence suggests that satisfactory performance in the ultrafines fraction will be achieved only by simul- taneously increasing the rate of flotation of the ultrafine valuable mineral and de- creasing the rate of entrainment of ultra- fine gangue.

Jan 1, 1984