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The procedure used for Truck Maintenance is described systematically in this paper. Emphasis is given to manpower required, work facilities, daily maintenance and oil sampling procedure. Scheduled Preventative Maintenance Service, Electrical Service, Component Change, Truck Overhaul and Outside Contractors are also discussed. The system used, achieves the required results with an average haul truck availability in 1981 of 87.9 per cent. INTRODUCTION Situated on the Island of Bougainville, in Papua New Guinea, the Bougainville Copper mine nestles in a valley near the crest of the Crown Prince Range, between 600 m and 980 m above sea level. The mine is serviced by two towns, Arawa - an open town on the Coast and Panguna at the Mine Site. Currently Bougainville Copper operates an open pit mine removing an average of 198 000 dry metric tonnes of material per day (115 000 tonnes ore and 83 000 tonnes of waste) with a fleet of electric shovels and 154 tonne electric haul trucks.

Jan 1, 1982

The Mount Lyell Company's concentrating mill is situated about a quarter of a mile westward of the portal of the North Lyell tunnel, which serves the North Lyell, Royal Tharsis and Crown Lyell mines, being on the 1100-ft. level of the first named. The Comstock mine is connected with the tram system at this level by five and a half miles of steam tramway, two-foot gauge being standard throughout.The plant is well placed with regard to all essential services and has an excellent water-supply from a series of three dams on the West Queen river.MILLING ORESThe mill feed is a mixture of the outputs from the foUr mines mentioned, each of which has its characteristic ore, but, generally speaking, about half of the ore consists of siliceous schists and the other half of hard grey quartzite. The schisty ores are easy to crush, but, on grinding, while the schist slimes readily, the quartz granules are hard, resulting in the handling of heavy loads on the secondary classifiers. The quartzite ores are both hard to crush and difficultto grind.The principal sulphide materials are bornite, chalcopyrite, and pyrite, chalcopyrite being the main copper-bearing mineral.The crystallization is coarse in the schisty ores, but it has been shown that even the 200 mesh (Tyler) material contains included sulphide particles. At the present time the sizing of the final tailing averages 80% through 200 mesh.

Jan 1, 1932

By Dickson B. L

Groundwater geochemistry is controlled by chemical interactions with aquifer rocks, and offers a powerful geochemical exploration technique for locating concealed mineral- isation. Techniques are applied for identifying constituents of aquifers using the compositions of their groundwaters, collected from the surface through drill holes, water bores or springs. Even slowly moving groundwaters have passed through large volumes of rocks which surround any sample site. Products from these rock-water contacts modify the groundwater. By relating water composition to the minerals from which the dissolved species may have been derived, geochemical exploration information is obtained for a significantly larger zone than is represented by drill hole rock samples. In this paper we describe some solution chemical tech- niques we are applying in mineral exploration, particularly in areas of Australia where ground- waters are highly saline and contain enhanced concentrations of trace metals. EQUILIBRIUM MODELS FOR SALINE GROUNDWATERS Central to our technique is the assumption that in low rainfall regions, aquifer rocks and contained groundwaters are in chemical equili- brium. Solubility calculations then allow us to predict upper limits to the soluble products of groundwater interaction with aquifer rocks and to identify minerals with which the groundwater is saturated. Whilst equilibrium calculations require input of concentrations of all dissolved species, they are actually based on "activity" of dissolved species rather than the analysed concentrations. Unless waters have very low ionic strengths (a measure of total dissolved solids), activity of a solute is not equal to its analytical concentration but equals concentration multiplied by an "activity coefficent". Several methods exist for calculating mineral solubilities. The ion-association model, commonly used in programs such as WATEQ (Truesdell and Jones, 1974) and later deriv- atives such as MINTEQ, assume the formation of complex ions such as MgSO4(0), CaCl+, which are described by formation constants. Activity coefficients are obtained by the extended Debye

Jan 1, 1988

By Baafi E. Y

Dragline monitoring systems are normally the best tool used to collect data on the machine performance and operational parameters of a dragline operation. This paper discusses results of a time study using data from a dragline monitoring syste

Jan 1, 1998

By Zingano A, Costa J. F

Brazilian amethyst production is mostly obtained from underground mines in the southernmost part of the country, involving approximately 6000 miners and generating an income of US$ 20 million per year. Amethyst-bearing geodes are hosted by Cretaceous continental flood basalts of the Serra Geral Formation. The economic zone occurs in the massive (colonnade) intermediary section of the Sao Gabriel Basalto. The tunnels and stopes follow the occurrence of geodes leading to an erratic and complex layout. A ground control survey revealed excessive roof convergence. Topographic results show excessive roof deformation and some roof falls have already been reported. To understand the ground conditions, prevent roof falls and better define the pillar dimensions detailed geomechanical mapping was carried out using the scanline method. Uniaxial compressive strength tests provided complementary information for rock mass classification. Results of the geomechanical classification were used to modify the mining layout taking into account the roof and pillar geomechanical characteristics. Retreat pillar mining minimised ground instability.

Jan 1, 1997

Increasing demands on quality of metallurgical grade alumina and for lower production costs led to the development of a new fluid bed calcining process. The process, jointly developed in Germany by Vereinigte Aluminium Werke A.G. and Lurgi Gesellschaften m.b.H., takes advantage of modern chemical engineering methods such as counter-current flow of combustion air and solids, direct heat-exchange between combustion air and fine solids and near stoichiometric combustion of oil in a fluid bed. Using a two-stage Venturi-type suspension preheater for heat-recovery from combustion flue- gases, the circulating fluid bed technique with internal oil combustion at 2.2000 F for the calcining step and 'a five-stage fluidized bed cooler for heat recovery from calcines, the process gives an outstanding heat- efficiency. In a first industrial plant for 560 sh. t. alumina per day heat consumption figures of less than 1.400 BTU/lb A12O3 were achieved.

Jan 1, 1971

Stressed steel cables, similar to those used in pre-stressed concrete, have been used for rock mass reinforcement, in civil engineering, for many years. This type of reinforcement has been attempted for open pit wall support, on several occasions, but has never gained wide acceptance as a practical approach because of high cost and complexity of installation in a mining environment. On the other hand, untensioned, fully grouted cable dowels (cable bolts) have gained wide acceptance for ground support in underground mining and it is perhaps surprising that this technique has not been used to a greater degree in open pit mining. The first systematic application of this technique in Australia was at the Mary Kathleen uranium mine in 1976, where it was spectacularly successful in maintaining steep stable walls in a jointed rock mass with unfavourably dipping structures. Cable bolting, and other techniques, are now being used to an increasing degree for wall support in both small and large open pits, for two basic applications: 1. stabilisation of potentially unstable sections of a wall, or 2. to allow steeper walls and reduce waste stripping volumes. In virtually every situation, wall rein- forcement has significant economic as well as technical advantages. The paper describes the development of the techniques, the mechanisms of wall support, the methods used, and discusses several case histories of its application to Australian open pit mines.

Jan 1, 1986

By Clappison D. J

Since its formation in Papua New Guinea and raising of A$2 million in 1980, Niugini Mining Limited (NML) has grown to a company capitalised on the Australian Stock Exchange at about A$350 million. In 1995 the company produced some 237 000 ounces of gold, 700 000 ounces of silver and nearly 5000 tonnes of copper from its operations at Red Dome, in North Queensland and San Cristobal in The Atacama Desert of Northern Chile. This production contrasts with Niugini Mining's first mining venture at Mt Victor in the Eastern Highlands of PNG which yielded 20 000 ounces of gold and 11 600 of silver between 1987 and 1989. Following the formation of an exploration joint venture in 1982 with Kennecott Explorations (Australia) Ltd, now a subsidiary of RTZ, Niugini Mining's early recognition of the gold potential of volcanic rocks at plate margins led to discovery of the Lihir deposit in July 1982. This deposit containing about 42 million ounces of gold in resources, is one of the largest undeveloped gold deposits in the world. Following raising of equity funds through the float of Lihir Gold Ltd and debt finance in 1995, construction of the mine at a cost of US$673 million is now underway with first full-scale production at approximately 600 000 ounces of gold per year expected in early- 1998.

Jan 1, 1996

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

South Africa is the world's largest producer of gold. The survival of its gold mining industry is dependent, to a large extent, on the successful implementation of new mining technology which reduces the operating costs. Gold mines of the country have a record of a high operational cost per tonne of rock excavated. The geology of the gold-bearing rock, in addition to the mining depth and the gold recoverable grade, profoundly affect the profitability of the industry. Among the other mining operations, drilling and blasting take a fair share of the mining cost. It is therefore proper to implement a dynamic approach of technological review aimed at combating the escalation of mining costs. Over the years, the industry has moved away from labour intensive activities. Mechanised operations are introduced where possible. Management techniques are oriented more towards better utilisation of human resources and machinery so as to enhance productivity in the stopes. This paper addresses the issue with particular reference to blasting operations in the stopes of deep gold mines. It reviews the conventional drilling and blasting techniques. It outlines some innovative changes brought about in the course of recent years with the aim of optimising productivity and the stope efficiency in particular. It focusses on the peculiarities of the blasting technology in deep mines. It discusses the issue of interaction between the high stress fields underground and the blasting generated stresses on rock fragmentation, as well as their impact on the remaining excavations. It anticipates the concept of the new technology of selective blasting in stoping. Finally it puts forward the crucial role played by management of the human factor underground.

Jan 1, 1995

By Morrison R. D, Kojovic T

Industry-sponsored research at the Julius Kruttschnitt Mineral Research Centre has produced models of high tension roll and electrostatic plate separators operating in mineral sands dry plants. The behaviour of mineral species has been characterised under a wide variety of operating conditions by extensive plant machine sampling and laboratory measurements. The effect of operating conditions on separator performance has been quantified by monitoring changes in the weight distribution of mineral species along the product splitter axis. The response of each mineral species has been modelled on a size-by-size basis using an average surface charge decay time and a variation in its surface properties. The models incorporate changes in machine, mineral and ambient conditions on the separation and predict all product flows, assays and size distributions. This paper outlines the structure of the models. These models are being implemented in JKSimSand, an user-friendly simulation software Package.

Jan 1, 1991

By Godresse M, Turczynski G. P J, Driver I. J, Low G, Ozawa N

Geological evaluations of coal deposits have been traditionally undertaken in a somewhat manual manner. Information is collected downhole by chip sampling, coring and using downhole geophysical logging. This information is then interpreted by an experienced geologist to define the coal and noncoal lithological units. Coal units were subsequently correlated to provide data for structural modelling. In recent years a number of advancements in interpretation techniques have been made based on Artificial Intelligence. This paper describes an integrated geological interpretation system based on maximised use of Al techniques. The first part describes the lithological interpretation which uses a number of boreholes with both logged lithology and downhole geophysical logs. This information provides a learning set of data to the neural network. The second part concentrates on the correlation of both coal and noncoal units from borehole to borehole. Problems in this area, in a manual sense, are interpretation of correlation across weathering zones and other geological anomolies. The technique is based on pattern recognition and dynamic programming techniques where a correlation matrix is developed relating all holes with their maximum correlations.

Jan 1, 1995

Intensive exploration for iron ore in the banded iron-formations (BIF) of the Pilbara region of Western Australia began in the early sixties and almost immediately established the Hamersley area as a major iron province. The early genetic models for the BIF-hosted ores were based mainly on macroscopic examinations of ores from the "hardcap" zone, and generally accepted a direct relationship with weathering effects on a Mesozoic to Tertiary land surface. Brandt (1964) was the first to suggest a difference in age between the high-grade hematite ores and the more common hematite-goethite types. He initially accepted a supergene origin for both, but later opted for a hydrothermal origin for the hematite ores. Apart from MacLeod (1966), the published views of the next decade reflect a largely parochial interpretation of individual ore bodies, centred mainly on supergene models but with some support for hydrothermal concepts. Except for Ayres (1971), none of the models were backed by detailed mineragraphic data. In 1976, an AMIRA-sponsored CSIRO group began a Province-wide investigation of the wide variety of ore types and BIF, with emphasis on geochemical and textural studies. The resulting conceptual model for a world-wide unified supergene and supergene-metamorphic hypothesis is generally accepted in the Hamersleys.

Jan 1, 1986

The Crown Minerals Act 1991 has introduced some significant changes to the New Zealand mining industry, not the least of which relate to the ability of miners to obtain access to land to conduct mining activities. This paper briefly reviews the relevant provisions of the Crown Minerals Act dealing with access arrangements, considers some typical features of access arrangements and examines a number of areas where problems may arise.

Jan 1, 1992

By Fowler T. J

Examples are provided of discontinuity analysis at selected sites in central Victoria. Discontinuities are rock fractures of low tensile strength, including bedding, foliations and joints, which are analysed during rock excavation design, to quantitatively determine the defect orientations, spacing and lengths. Their analysis can reduce the cost of mining operation and improve safety. Extrapolation beyond the exposed face is required, although difficult without an understanding of the regional geology. For rock engineering purposes assumptions are commonly made that discontinuity characteristics are uniform throughout the rock mass, however this is often invalid, as rock masses have usually undergone large-scale deformation, exhibit anisotropy and inhomogeneity. Structural geologists are able to interpret large-scale deformation responses for the purposes of structural correlation and extrapolation. Examples of discontinuity analysis linked to regional geological assesment from sites in central Victoria, reveal that discontinuities exhibit similar characteristics in a range of rock types of different ages and composition. Spacing variations between individual sites are believed to be a result of local rock type differences.

Jan 1, 1997

By Sims D. A

This paper primarily describes the application of geology to the different mining methods employed in a large underground mine. The steeply dipping stratiform Silver/Lead/Zinc mineralisation at Mount Isa include up to 28 mineable orebodies. The orebodiea are mined by cut and fill, sublevel benching and sublevel open stoping; the method chosen depending mainly on orebody geomechanics.The sources and methods of data collection, and the interpretation process undertaken, are described. The paper emphasises the different geological input required, by each individual mining method, to provide the necessary production and strata control. This input contributes significantly to the success and efficiency of the operations.

Jan 1, 1990

The long continuing controversy over the Origin of fusain, whether it is a product of primeval forest fires, or of special conditions of weathering (including bacterial decay) of the vegetal debris concerned prior to, burial, has now been extended, to include the possibility that fusain is a product of the coalifaction process subsequent to deposition, so that doubt may reach even to its time of formation.The conflicting views on this point are summarised in the following quotations from two recent publications (my italics in each quotation):1. "Recent observations made in peat and brown coal deposits in Australia, England and Germany strongly suggest that practically all fusain is formed by coalifaction after deposition and 'preliminary compression. In deposits of advanced brown coal rank, it normally takes the shape of pieces of wood compressed parallel to the bedding plane; and some fragments consisting partly of fusain and partly of vitrain exhibit the same amount of compression throughout. This would seem to indicate fusinisation after burial, as hard brittle charcoal would be crushed, or else retain its original irregular shape if strong enough to withstand pressure.In some immature deposits, however, where cover is of a hydrostatic nature rather than a vertical compressionar force, occasional pieces of fusinised wood showing very little flattening are present, but such immature deposits seldom contain the proportion of fusain found in higher rank coals. In view of this, and the possibility of introduction of charcoal into peat deposits, it is felt that a small amount of the fusain in coal may represent wood charred before burial, but most of it almost certaInly originated as a product of fusinisation after burial" (Dulhunty, 1948, p.14).

Jan 1, 1953

Rockbursts, as they occur in South African deep level gold mines, have a lot in common with natural earthquakes. Both violently release seismic energy and cause damage to underground and surface structures. Rockbursts are the main cause of fatalities in deep gold mines and the problem may increase in severity with future mining at greater depths. Although the emphasis in Rock mechanics is on the prevention of rockbursts, prediction would provide a partial solution to the rockburst problem. A research project was initiated in 1981 on Western Deep Levels to investigate the possibility of detecting and identifying precursive microseismic activity. This project has succeeded in locating potential sources of seismic events with reasonable confidence. The timing of these events may be estimated with less confidence, and an important parameter, namely the potential size of the rockburst, still cannot be determined. An example of a large seismic event and its associated precursive activity are discussed. Practical prediction systems will, at least for some time, involve subjective decision making which will place a new responsibility on the mine manager as well as the rockburst specialist. The moral pressure on the manager as the final decision maker will probably be greater than the fear of leqal prosecution.

Jan 1, 1986

Arm Royalty systems of different types are used throughout Australia by both state and federal governments to raise revenue and thus facilitate in the proper distribution of mineral wealth. Royalty systems should be neutral and equitable but by their very nature these objectives are impossible to obtain. Because of the individual nature of mineral deposits, in particular variable cutoff grades and tonnages, governments should be aware of the possible trade off between short and long term gains of the particular royalty scheme introduced.

Jan 1, 1982

Contracts are widely used in mining to provide self motivation in an environ-ment of isolated work places. Which incentives to use and how to implement them has long been the subject of numerous discussions. The mines operated by Australian Mining and Smelting at Broken Hill have evolved several guidelines to follow when developing contracts.Identify the main purpose of the work and use this as the basis of measurement for the contract. Therefore stoping achievement would be measured by tonnes extracted, development by metres driven. Paying for other work activities such as standing timber in timber stoping must detract from the percentage of the total contract paid per tonne produced. Concentrating on the main activity and applying the majority of contract pay to that task reinforces at is beneficial to both the miners and the whole operation.

Jan 1, 1985