Search Documents

This paper is for mine managers. It is about maintenance of mining equipment. This is an extremely broad subject so this paper is given with the caveat that it necessarily contains generalisations, not true in all cases, but broadly correct. The job of mine managers is to be good at making money from the excavation and preliminary treatment of mineral. To do this well, they need to understand the cost and value drivers in the business. This includes understanding the drivers associated with maintenance. Maintenance is often identified as a problem at mine sites. It is frequently listed as the cause of production shortfalls when reporting. The state of maintenance within mining as an industry is generally among the lower end of the range, when compared to manufacturing, petrochemicals, etc. Why is this? Experience and review of many audits and evaluations of maintenance has shown that some patterns are consistent with good performance and some consistent with poor performance. These often centre around the time horizon of the management team and are associated with knowing the sensitivity of the business to certain maintenance drivers and the mechanisms of maintenance and their results. To summarise, some common misunderstandings can be listed as statements that are obvious and extrapolations from those, which are not necessarily correct. For example: High availability of equipment is necessary for production. Incorrect extrapolation:focus on availability will produce high production. Design is often the greatest factor in determining the reliability of a mining machine. Incorrect extrapolation: the newest and biggest machines generally have the lowest cost operations. Operation has an enormous impact on machine productivity and reliability. Incorrect extrapolation: the fastest operators are generally the best from a productive point of view. Some maintenance improves the performance and reliability of machines. Incorrect extrapolation: more maintenance will give you more reliability. Some maintenance depends on disassembly and reassembly of components. Incorrect extrapolation: assembly is basically the reverse process of disassembly. Maintenance improvement in the mining industry in the last 15 years has focused largely on planning and systems improvement. Incorrect extrapolation: most of the problems in maintenance can be traced to a lack of planning. Actions based on flawed extrapolations will steer a business suboptimally. It is therefore important that the mine manager understands these issues so that the improvement effort can be directed to the greatest benefit.

Jan 1, 2006

By I Brunton

Blast fragmentation can have a significant impact on the profitability of a mine. An optimum run of mine (ROM) size distribution is required to maximise the performance of downstream processes. If this fragmentation size distribution can be modelled and controlled, the operation will have made a significant advancement towards improving its performance. Blast fragmentation modelling is an important step in Mine to MillTM optimisation. It allows the estimation of blast fragmentation distributions for a number of different rock mass, blast geometry, and explosive parameters. These distributions can then be modelled in downstream mining and milling processes to determine the optimum blast design. When a blast hole is detonated rock breakage occurs in two different stress regions û compressive and tensile. In the first region, compressive stress waves form a æcrushed zoneÆ directly adjacent to the blast hole. The second region, termed the æcracked zoneÆ, occurs outside the crush one. The widely used Kuz-Ram model does not recognise these two blast regions. In the Kuz-Ram model the mean fragment size from the blast is approximated and is then used to estimate the remaining size distribution. Experience has shown that this model predicts the coarse end reasonably accurately, but it can significantly underestimate the amount of fines generated. As part of the Australian Mineral Industries Research Association (AMIRA) P483A Mine to MillTM project, the Two-Component Model (TCM) and Crush Zone Model (CZM), developed by the Julius Kruttschnitt Mineral Research Centre (JKMRC), were compared and evaluated to measured ROM fragmentation distributions. An important criteria for this comparison was the variation of model results from measured ROM in the fine to intermediate section (1 mm to 100 mm) of the fragmentation curve. This region of the distribution is important for Mine to MillTM optimisation. The comparison of modelled and Split ROM fragmentation distributions has been conducted in harder ores (UCS greater than 80 MPa). Further work involves modelling softer ores. The comparisons will be continued with future site surveys to increase confidence in the comparison of the CZM and TCM to Split results. Stochastic fragmentation modelling will then be conducted to take into account variation of input parameters. A window of possible fragmentation distributions can be compared to those obtained by Split. Following this work, an improved fragmentation model will be developed in response to these findings.

Jan 1, 2001

INDEX OF CONTENTSIntroduction.Systems of classification of coals.RankClassification of Australian coals.Defects of systems in use in other countries.Indexing by Fuel Ratio.Classification by Ultimate Carbon/Ultimate Hydrogen.Relationship between Fuel Ratio and ultimate composition.Suggested convention for classification.Origin and Evolution.Notes on directions of change of composition on Carbon Hydrogen chart.Summary and conclusion.Acknowledgments.Bibliography.Appendix.

Jan 1, 1948

By Dudgeon RN, Houston ML

When the original Mount Gunson joint venture,between CSR Limited and United Uranium N.L. ceased operations in December 1971, an intensive exploration campaign was launched to prospect for more ore in the Mount Gunson region. This campaign resulted in the dis- covery'of the Cattle Grid copper deposit. A comprehensive sampling pro- gramme including the sinking of over 200 diamond drill holes and two vertical shafts,proved the existence of 4.6 million tonnes of ore, at a mean grade of 2.4% Cu,calculated at 1.00% Cu cutoff.

Jan 1, 1975

By Gadsden R. W

Physical and chemical requirements are defined for coke and ferrous materials used in modern high productivity blast furnaces operating in Australian conditions. Recent developments in the type of equipment required to be installed at the steelworks to ensure these requirements are described with illustrations from current plant practice provided.

Jan 1, 1976

Mining has long been an important activity for the people of Australia. The Aboriginals used rocks and minerals in their culture many thousand years before European settlement. It was not until 1840 that silver-lead ore was discovered in the Mount Lofty Ranges, and developed as Australia's first metalliferous mine.

Jan 1, 1995

By Barnett LJ

The Kellogg slag fuming model is extended to apply to the Port Pirie plant which uses recuperative heating of secondary air. Exten- sive investigations of plant operations pro- vide parameters for use with the model, and verification that the resulting model provides simulation which is very close to actual plant performance. The model is used to_deter- mine optimum slag fuming operating conditions, and the results of several other investigations with the model are briefly described.

Jan 1, 1975

By Gardner CE

Uranium occurrences and the probable Australian reserves are discussed and the recovery and processing methods used in treatment plants at Radium Hill and Port Pirie, S.A., Rum Jungle and Moline, N.T., and Mary Kathleen, Qid. are reviewed. The broad aspects of the application of nuclear power in Australia are then considered, and those factors of greatest significance are highlighted. It is these factors that are most likely to dictate the future role of nuclear generation in Australia. In commenting on private industry applications, the paper emphasises that each case must be considered on its own merits, and a warning is given that general statements can be misleading. In the long-term situation nuclear power is considered to be capable of playing a leading role and the discussion covers desalination and high load industries although short term applications appear difficult to justify. In non-power applications for nuclear energy reference is made to isotopes and the uses of nuclear devices in mining and civil engineering with a pertinent comment on safety.

Jan 1, 1970

Organic dyes such as nigrosine and sun yellow act as depressants for carbonaceous particles in the, flotation of sulphide ores. Depression is achieved when initially hydrophobic organic surfaces are made hydrophilic by preferential adsorption of dye molecules. Experimental studies, mainly on Mount Isa ores, indicate that dyes are adsorbed as planar anionic micelles attached to carbonaceous surfaces by van der Waals and ion exchange attractive interactions. Relationships appear to exist between the amount of organic matter on the surface of ground particles, the surface area of the particles, the "saturation" adsorptions of dyes, and the degree of difficulty experienced during froth flotation.

Jan 1, 1975

The design of the grinding section is discussed and details are given of the equipment installed for the autogenous grinding of ores from the C.S.A. mine at Cobar.The first section of the concentrator commenced treating ore in June, 1965 and operating experience and maintenance requirements since that time are outlined.

Jan 1, 1969

FINANCE FOR EXPLORATION Two factors have basic importance in relation to the availability of finance: the apparent success of continuing exploration activity and tax concessions. It is not proposed to discuss the effect of existing tax incentives, as these have already been outlined and are generally accepted as being reasonably attractive; certainly not a deterrent to possible investors. However, it is obvious that the greater the tax incentives, the greater the amount of money that will be attracted, and the wider the number of people who can be brought into the pool. If, as is suggested, the chance of discovery is related to expenditure and effort, then the more money attracted, the better the prospects of significant finds. It is probably correct to assume that the largest expenditure in mining will come from, or be induced by, people expert in the field, people who are fully aware of the risks and benefits and perhaps making conservative decisions because of this awareness. Insofar as the general public is concerned, while in the first burst of enthusiasm it will frequently follow any promoter, in the long run it too will become more sophisticated and will strongly support only those promoters and companies of good repute and proven record.

Jan 1, 1971

For the purpose of this paper the Otago Region is that covered by the Otago Regional Council. This area, like other South Island Regions, has a river system starting in the Mountains and are all gravel bed rivers. The gravel from these rivers has been the major source of aggregate in the region since the development of the province began. The majority of the aggregate is a mix of greywacke, schist and quartz, which will be referred to later with its production problems. The region has been broken down into various areas.

Jan 1, 1992

In the- past, at Great Boulder Gold Mines Ltd,, ,' s.. number of attempts ' ha'tre been made to remove water ' `solublo copper and' iron sa'lt's from calcined pyritic concentrates, but various problems have arisen and the methodsi ve been abandoned. A method of rapid washing has now been developed,, and although some problems still. exist,, a workable `process has boreh established .which. has; resulted in 'substantial savings of 'reagents used for. the. cyanidation of calcine

Jan 1, 1964

The Plant Control and Data Logging System for the Loy Yang Open Cut (LYOC) is part of a control and communications network designed to provide a high level of surveillance of open cut plant and facilitate the efficient co- ordination of operations and plant maintenance. The computer system selected utilises a central dual mini-computer and multiple microcomputer data transmission network ,linked to the plant controllers using distributed, microcomputer based remote data collectors or outstations. Several aspects of the computer system are outlined.

Jan 1, 1982

Although most N.S.W. coal mines contain large amounts of combustible materials such as coal and timber, the introduction of mechanisation has extended the range of combustible materials now found underground. The role of combustible material in a fire is not clearly understood and as a result the assessment of these materials for flammability by small and large scale tests is doubtful. Extensive research has been carried out on the toxic and irritating gases evolved during the combustion of plastics. However, most autopsies report death due to carbon monoxide inhalation because the combined toxicity of smoke and fire gases is unknown.

Jan 1, 1981

By Ritchie I

Copper minerals are often associated with gold ores. These create processing problems since cyanide solutions are not selective for gold alone. Copper minerals are also leached by cyanide, and typically each one per cent of `reactive' copper in the ore consumes about 30 kg t 1 cyanide. Once in solution, copper cyanide species create further processing problems as they adsorb onto carbon along with the dicyanoaurate ion. These problems make conventional cyanidation of gold ore uneconomic if the ore contains too much copper. As a result, methods of economically processing gold-copper ores are becoming of increasing importance.One of the more promising methods of treating these ores is by selective leaching of the gold by an ammoniacal cyanide solution, a method first described by Hunt in 1901. This method is already in commercial use in Mauritania, treating copper/gold tailings. In general terms, the addition of I - 2 g U1 ammonia to a standard cyanide leach solution causes a significant increase in gold extraction and decrease in copper extraction. However, early testwork on this system has concluded that the optimal leach conditions are critically dependent on ore composition, and the mechanism is not well understood, making predictions of best conditions impossible.

Jan 1, 1997

This paper examines the methods and people required for the evaluation of project or corporate acquisitions. Experience over the past five years has shown that some growth can be achieved by carefully evaluated acquisition of gold projects within regions where the acquiring company has gold processing facilities. Many Western Australian companies have participated in this process and the trend seems likely to continue with a diminishing number of larger producing companies controlling through joint venture or direct purchase of widely spaced ore deposits. In some cases the acquisition may include ore processing facilities, however an increasing number of smaller project acquisitions, involving small open pit gold deposits, which are within trucking distance of the acquiring company's mill. Whilst gold prices remain at the current depressed level we can expect to see this trend continue.

Jan 1, 1989

By Thomas E. G

In the economic evaluation of any Australian mining project, changes in taxation can significantly affect viability. Australian tax laws, particularly in the period since early 1973, have undergone many changes which have led to shifts in the profitability of mining companies. This paper examines the sensitivity of a selected, broadly based sample of Australian mining companies to the changes that have occurred, or are reasonably likely to occur, in taxation legislation. In the past, tax systems have been altered for a variety of reasons, such as 1. reduction'in the impact of inflation 2. neutralization of incidence between different sections of the economy 3. as an incentive to encourage expansion and growth in a particular industry or area, and 4. increase in the real "take" of government. In this paper, conventional rate of return analyses are applied in a study of how profitability is affected under various taxation systems.

Jan 1, 1977

The Savage River Mines concentrator and pipeline has operated for seven years. During this time some problems of general interest have been overcome, particularly in the area of autogenous grinding in large mills and in pump- ing solids over long distances. The plant flow sheet and equipment at Savage River and the control techniques are. described. Ore type has varied widely over the per- iod of plant operation. Techniques developed to minimise the effect of variations on through- put are discussed'. The main technique is the controlled rejection or addition of grinding Media.

Jan 1, 1975

The short review of hydrogeologic conditions in the three Polish coal basins have been presented as the background for the prevention measures against water inrushes being underta- ken in coal mines. The Polish mine safety regulations concerning water inrush prevention have been discussed, namely: - classification of sources of the potential water inrushes, - levels of water inrush risk and conditions of mining operation in the mines facing particular risk levels, - determination of the -di.mens.ons.of protecting pillars to prevent water inrush to mines, protection of surface water reservoirs and their earth embankments in regions submitted to mining deformations. Three examples of coal mining being carried out under water bodies have been presented.

Jan 1, 1988