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By Nixon TR

The Australian Coal Industry Research Laboratories Ltd. (A.C.I.R.L.) MINVENT computer program can be used to simulate existing and projected colliery ventilation requirements. New collieries can be planned using a database of ventilation parameters which were ascertain- ed by A.C.I.R.L. surveys at selected collieries in N.S.W. and Queensland. Several techniques are used in both the formulation of the database and in the evaluat- ion of a ventilation system, prior to analysis by the MINVENT program. The analysis of a ventilation system requires the measurement of air quantities, pressures and hence airway resistances. All resistances are calculated at standard air density of 1.205 kg/m3. Air densities are derived from barometric pressure and wet and dry bulb temperature readings. Airway frictional and shock losses, leakage through stoppings and overcasts, flow of air through regulators, face resistance and resistance of anomalous ventilation features are related to the typical Australian measured data presented.

Jan 1, 1983

By Ehlert G, Steinlechner E

The paper describes a new process for filtration which combines the continuous operation of conventional vacuum filters with the low final moisture contents hitherto only achievable with plate and frame presses. The increasingly high portion of fine particles causes several problems in the filtration of copper concentrates. One drawback is that remarkable quantities of liquid are attached to the very fine particles because of their specific surface area. Furthermore, fine particles also reduce the size of the capillaries in the filter cake, thus increasing the critical pressure which any filtration system has to exceed to achieve the desired final cake moisture. The maximum filtration pressure of conventional vacuum filters is limited by nature itself and by practical aspects to approximately 0.75 bar. The hyperbaric filter combines the continuous operating principle with an increase in filtration pressure of up to 6 bar simply by placing the entire disc or drum filter inside a pressure vessel. The major machine components and process features are explained in the details of the paper. After extensive research and field testing, 23 ANDRITZ hyperbaric filters, with a total filtration area of 1968 m2 have now been sold. Seventeen of these units (1440 m2) are in commercial use and more units are, on order. Performance data on copper concentrates from plants in Australia, South America, Poland, Africa and North America are outlined in detail. Compared to vacuum filters, generally hyperbaric filters will reduce the final cake moisture of concentrates with 75 per cent

Jan 1, 1993

The author describes 1. The classification and characteristics of various thick seam mining techniques in various Japanese coal mines. 2. Practices of thick seam mining methods experienced in Taiheiyo Coal Mine. Currently, thick single lift, simultaneous multi lift and non simul- taneous multi lift mining methods are adopted as underground flat thick seam excavations in Japan. These are now reliable and effective in increasing the extraction ratio. At Kushiro Colliery of Taiheiyo Coal Mining Co., these three thick seam mining methods have been used. According to the results, if solidification of the top lift goaf is essential, the non simul- taneous multi lift mining method is the most effective in increasing the extraction ratio without minimising productivity of each lift and it points out that further development of this method is necessary.

Jan 1, 1976

Grey River Gold Mining Ltd commenced dredging alluvial flats in the Grey River Valley in 1989.Previous drilling indicated over 100 million cubic metres of gravels with some 90% of the gold in the bottom 7 metres.The dredge built by Rahco, Spokane, was innovative in a number of aspects but particularly in the fact that a separate ladder with a cutter and pump was used to strip the overburden and a bucketline to mine the gold bearing wash below.Metallurgical studies and exploration were initiated when the project commenced; Leasing and environmental considerations were investigated and action taken.While progress is being made, the operation at this stage is not meeting required production and performance. Main problems have been with the stripping system and wear.

Jan 1, 1990

From the ventilation aspect, there is a basic difference between advancing and ezreating longwall layouts. Particular rroblems with retreating, using differing mining methods and layouts include high gas emissions, spontaneous combustion and -radients. There is an acceptable method of crntrolling the environment at the return end a retreating longwall face without the use a multiple heading system. Incorporated in the design is the facility to practice xtensive methane drainage, thus ensuring a ntrol of the rate of methane emission into the main roadways. Case studies highlight varying mining editions under which the proposed system of Ctised.

Jan 1, 1982

Conditional simulation is a branch of geo- statistics which allows the simulation of a mineral deposit so that predictions can be made about the variability of some particular parameter of the deposit. A summary of the general principles, advantages and limitations of conditional simulation is presented together with an example based on coal seam thickness.

Jan 1, 1981

By Else D

While the underground mining work environment may have processes and equipment considered unique, most of the broad issues likely to affect the occupational health and safety of employees are not. One such occupational health and safety issue that is common to the mining sector and most other industries is noise. Noise as an occupational health and safety issue is of national significance. Presently noise induced hearing loss costs Australia around $35 million per year on compensation claims experience alone. Noisy equipment and work environments are still being tolerated in parts of the mining industry as `part of the job'. Where work has been undertaken in noise management, considerable emphasis has been placed on either industrial hygiene monitoring programs or the provision of hearing protectors to miners working on or around noisy equipment.Opportunities for more cost-effective and long term methods for controlling noise exist. Ready to apply solutions to noise problems in the mining industry are available, but for many mining operators this information is often difficult to obtain. To overcome this problem, the SHARE program collects and distributes solutions to occupational health and safety problems. The program aims to help organisations to close the gap between what is known about solving health and safety problems and what is actually being applied at the shop floor level: Recent developments have incorporated the SHARE program concept into worksite hazard management projects that involve the participation of employee representatives, front line supervisors and engineering personnel. Besides providing workforce members with an increased understanding of hazard management skills, the SHARE in-house program results in the implementation and sharing of solutions to health and safety problems by the program participants.

Jan 1, 1992

By Ypma PJM

The Westmoreland uranium deposits occur on the northern flank of the Murphy Tectonic Ridge in the upper member of the Westmoreland Conglom- erate. Uranium mineralization is spatially associated with the contact of the overlying basaltic Siegal Volcanics and the margins of in- trusive dolerite dykes which are geochemically similar to the Siegal Volcanics. Thermoluminescence (TL) measurements on 800 samples from within the orebodies and surr- ounding host rock (up to 8 kilometres away from the deposits) have indicated that all of the Westmoreland Conglomerate has suffered major radiation damagg attributable to at least 10 ppm uranium over 10 years. The underlying rhyolitic Mid Proterozoic Cliffdale Volcanics have distinctive TL glow curves indicative of radiation sensitization caused by high uranium contents. These vol- canics are part of the Mid Proterozoic volcanic event known to be enriched in uranium. The Westmoreland Conglomerate has been derived by erosion of the uranium-rich Cliffdale Volcanics and associated Nicholson Granite Complex which makes it likely that the Westmoreland Conglom- erate had a high inherent uranium content.

Jan 1, 1984

The intent of this address is to look forward into the 21st Century and present certain thoughts as to how underground coal mining might be conducted. The views in this talk are based principally on the author's experience with mining practices in the United States. It may be difficult to accept, but the 21st Century is a mere 12 years away. What new techniques will be available? To develop an understanding of the way in which technology has been and could be changing, a two- stage analysis is made of mining technology for U.S. Coal. The first phase covers the period 1975 to the present, while the second includes 1960 to 1975. This historical perspective includes a view of underground production by mining methods, considerations of labour productivity, and a review of accident and fatality rates. Several topics are important features of this historical analysis. Among the most significant are: (1) the introduction of Ion-wall mining technology into U.S. underground coal mines, (2) the use of computers to assist in mine planning and design activities, (3) major efforts to improve health and safety performance, with emphasis on underground dust control, and (4) improvements in mining equipment with an eye towards increased reliability and up-time performance. Based on that historical perspective, projections are made in three increments. The first being immediately at the turn of the century, the second being a dozen or so years beyond that, and the third being at the quarter point of the 21st Century.

Jan 1, 1988

By Grant J

In surface mining, significant improvements in efficiency can be obtained through greater control over the formation of the muckpile. By tailoring the muckpile shape and its looseness to the requirements of the excavating equipment savings can be rea- lised through increased production, machine life and reduced maintenance. For instance, one open cut coal mine has recently estimated that a 2001o improvement in its front row throw would realise $320,000/year savings in rehandle costs alone. Previously greater throw has been achieved by increasing the powder factor through increased quantity of explosive or by drill- ing a larger number of holes-both at a significant cost penalty. However a recent series of experimental blasts demonstrated that it was possible to achieve a twofold increase in the distance of throw of a single row blast by simply changing delay timing alone. The Nobel Electronic Delay Detonator was used to provide the timing flexibility and control required for a thorough study of the effect of blast timing on heave. Whilst it is well accepted that the front row of a blast dominates the extent of throw, it was also found that the profile of the blast could be significantly altered. To date, the general consensus has been that the muckpile for- mation from a blast is a function of the blast geometry, the rock type, the explosive and the initiation sequence. Typically the geometry, rock type and initiation system have a far greater impact than the explosive type. This has been demonstrated by many high speed film studies. However the extent of influence via initiation has rarely been fully evaluated, owing largely to the limited control offered by conventional detonators.

Jan 1, 1988

By P J. Clark, A W. Fisher, R G. Ford

Site characterisation of subsurface contaminant transport is often hampered by a lack of knowledge of site heterogeneity and temporal variations in hydrogeochemistry. The use of a regional-scale data compilation derived from satellite imaging is discussed with respect to directing design of site characterisation to monitor the fate of a Dense Non-Aqueous Phase Liquid (DNAPL) plume in Nevada. Evaluation of the drainage basin contributing to the groundwater flux into the study site was used to re-assess the site conceptual model and re-direct the characterisation effort. The use of highly resolved measurements of subsurface hydrogeochemistry in space and time were employed to identify the predominant biogeochemical processes controlling arsenic transport during discharge of groundwater into a pond at a site in Massachusetts. Direct-push conductivity measurements coupled with vertically-resolved sampling within the pond and adjoining aquifer demonstrated spatial and temporal variations in dissolved arsenic within groundwater and the pond water column and sediment pore water. Spatial variability was observed over the scale of centimetres to metres, and temporal variations were observed over the scales of days (following storm events) to seasons. Microbially-driven redox processes maintained anoxic conditions in groundwater and at the sediment-water interface (iron and sulfate reduction) and exerted both a direct and indirect influence on arsenic solution speciation and partitioning to surface water sediments.

Jan 1, 2004

By Jensen B, Ofori P, He Y, White E, Stanmore B, Brien M, O&apos

As part of a large AMIRA project, an on-line moisture meter was installed at two mine sites in Central Queensland. This project investigated the factors which control the moisture content of coarse (>0.5 mm) coal from the centrifuges used in conventional coal preparation plants. It was placed immediately after the first centrifuge to isolate the factors pertaining to one machine and its feed.The meter was found to be accurate and precise when compared with manual and mechanical sampling methods. The Grubbs estimator technique indicated that its precision is better than 0.3 per cent at the 95 per cent confidence limit.It has been identified that:1. the variability of the measured moisture contents of coarse coal can be described by normal distributions. Standard deviations of about 0.6 per cent are common; and2. the treatment of the coarse coal on the drain and rinse screens immediately prior to the centrifuge can affect the final moisture content.

Jan 1, 1995

The operation of quarries for the production of crushed stone and aggregates, depends heavily on rock blasting efficiency, which usually represents a major share of total production costs. After investigating the causes of this situation, a series of technical aspects have been detected, and they are described for the purpose of contributing to the minimization of costs, which also reduces the effects of blasting on the environment. Utilization of empirical design methods, of inadequate explosive types, and of erroneous drilling pauems with respect to rock properties, are the main factors to be corrected, as a consequence of poor engineering criteria, with scarce use of computational methods and field instrumentation. Several concepts of blasting optimization are pointed out, and their application to industrial operations in a Portuguese limestone quarry indicated clear trends for the reduction of production costs, as well as some of the deleterious consequences of blasting on the environment.

Jan 1, 1990

Expert systems are a product of Artificial Intelligence (AI), a field of long standing, dedicated to the study of problem solving using heuristics, construction of symbolic representations of knowledge about the world, communications proce

Jan 1, 1998

The Macquarie Dictionary defines `information' as: knowledge communicated or received concerning some fact or circumstance; (in communicating theory): a quantitative measure of the contents of a message. For mining companies investing in data capture and information processing technology for operations management is a key issue. Beyond producing performance related information that employees can relate to it is being able to deliver that information into the workplace when it is required, to the employees that can utilise it. To be effective the data needs to be received and understood as `information'. The technology is now available and proven to enable `information' to be delivered into the mining workplace adding value to the activities performed by mine employees. The application of computers and information technology in the mining industry has typically been limited to the resource definition and planning stages, accounting and administration and the process plants that treat the ores and minerals. The mining extraction processes that consume expenditure and determine output in a mining operation occur in an environment dominated by unpredictable events and variable conditions. The mining operation has long been regarded as an inexact science conducted in unpredictable circumstances with many independent variables affecting the output and resultant cost of production. Financial accountants keep track of expenditure and management accountants analyse the cost of production usually on a weekly or monthly basis but all this effort can't affect the outcome, that was determined by the real time events and variations of circumstances over a week ago. Such reporting and analysis can result in conclusions being drawn about what improvements can be made and how you might do better next time, but generally the data is not detailed enough, is inaccurate or misrepresents the real issues. The capital investment required for any mining operation is substantial and comparable to other industries such as manufacturing. The performance and utilisation of manufacturing plants is usually closely monitored down to the lowest level of detail. Many modern plants are controlled and optimised using programmable intelligent devices and monitors display real time performance to the operators and prompt them to make informed decisions to maximise production and minimise wastage. Technology suitable for the mining industry is now widely available and has proven to be a reliable and powerful tool for the optimisation of mining operations. This paper focuses on the latest information technology developed by Modular Mining Systems that has been implemented in mining operations worldwide. The benefits reported by the mining companies utilising real time information technology over the past 15 years have generally related to optimisation of truck fleet allocation and material blending. Some mining operations have reported improvements in equipment utilisation of greater than 20 per cent. With the development of real time graphical display screens in the operators cabins the benefits of information delivery can be harnessed to make employees more effective in the workplace.

Jan 1, 1995

Structural geological information is widely used at the Mt Whaleback Mine, Newman, WA. Recent improvements in the structural understanding of Mt Whaleback are providing a very cost-effective way of reducing geological risk, improving the economics of mining, optimising pit design and addressing safety problems. The structure of the Mt Whaleback orebody is highly complex and has a significant influence not only on iron ore genesis but also on pit wall stability. A team approach between the Structural Geology and Geomechanics Groups has been providing excellent results to reduce geological risk at Mt Whaleback.

Jan 1, 1994

Tectonic subsidence plots have been calculated for well, extrapolated-well and significant off-well (seismically-based) locations in the Vulcan Sub-basin and adjacent highs (western Timor Sea). The subsidence curves have been normalized to a common datum, the distinctive "near top Permian" marker, and corrected for sediment compaction, palaeobathymetry, eustatic sea-level change and loading effects.Four principal phases of post-Permian basin development are recognised and quantitatively described by integrating the results of the sub-sidence analysis into the regional (e.g. recent Ocean Drilling Program-derived) framework of the tectonic evolution of the North West Shelf. They are1. the Triassic-mid Jurassic Westralian Superbasin intracratonic phase,2. the late Jurassic-early Cretaceous North West Shelf rift phase,3. the mid Cretaceous-Palaeogene North West Shelf subsidence phase, and4. the Neogene-present Timor collision phase. Rapid Triassic tectonic subsidence occurred in an intracratonic setting, possibly subsequent to aborted late Palaeozoic rifting. Intracratonic sub-sidence mechanisms such as deep crustal metamorphism and/or intrustion and regional tectonic compression are invoked in addition to any post-rift thermal subsidence which may have occurred.

Jan 1, 1990

Computers represent substantial capital investment. A better return on that invest- ment comes from more effective use of the computer's facilities. By using Telecom's data communications facilities, more people in more locations can have ready access to those facilities.

Jan 1, 1983

By Fairhurst RM

High pressure abrasive water jets have been shown capable of cutting a wide range of materials including steel, stone, rock and concrete. Acceptable performance can be achieved using relatively low pressures and expendable abrasives. The cutting head can be made small and abrasive feed systems have been developed that allow reliable pumping of slurries over long distances to supply such cutting heads. These features make abrasive water jets ideally suited to automated control in remote areas.Another major advantage of abrasive entraining water jet cutting heads is that they may be operated safely in potentially explosive environments due to their cold cutting ability. Therefore there are many possible applications for such equipment in mining.This paper gives an introduction to the abrasive water jet process and includes results of trials carried out at BHRA on a range of hard materials. Work is also described which investigated the operational safety of abrasive water jets in explosive environ-ments. In a special environmental chamber, cuts were made on steel and sandstone with atmospheres of methane/air and hydrogen/air, without caypsing ignition.

Jan 1, 1985

Australian continental crust has accreted and consolidated by thirds: 1/3 during Archean time, 1/3 during Early to mid- Proterozoic time, and 1/3 during latest Precambrian to mostly Paleozoic time. The progression of orogenic systems and the crustal consolidations they represent seem not fundamentally different in basic orogenic processes from better known Mesozoic-Cenozoic examples in that accretionary, continental margin, collisional, and intraplate intracratonic inverted and/or reactivated systems are all recognizable in the tectonic evolution of Australia.

Jan 1, 1995