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Disastrous earthquakes are a reality on the Australiancontinent. Unfortunately it has taken the fatal 1989 New-castle earthquake to demonstrate to all Australians that we do not reside on a "stable continent". While the world accepts the potential of plate tectonics and its associated plate margin earthquakes, particularly around the active Pacific Rim, the realisation of devastating intra-plate, or continental, earthquakes is only now beginning to take effect. The 1989 Newcastle earthquake provides many lessons on which to further fundamental earthquake research and the applications to the future welfare of human civilisation. To mitigate the earthquake hazard in relation to the devastation to life, property and industry, research must be undertaken with the resulting informa-tion to be included in the nation's disaster management programs. The earthquake hazard is everpresent in east-ern Australia and the major step in its quantification is a more realistic determination of earthquake risk estimates through an integrated study of seismology, engineering, insurance and sociology.

Jan 1, 1990

By J Kinal

Plant trials are at the best of times difficult to perform; given variations in the ore, operating practice and economic constraints placed on a plant. Testing grinding media at industrial scale adds a further level of complexity that needs to be accounted for.Laboratory test programs consistently demonstrate that altering the grinding chemistry through the application of inert grinding media has the potential to provide significant metallurgical benefit. However, prog- ressing from laboratory testing to industrial trial is often an agonisingly slow process that can lead to inconclusive results which raise more questions than give answers. There are many factors that need to be considered when conducting plant trials aimed at demonstrating the impact of inert grinding media on metallurgical performance. The decisions (or lack thereof) made during the planning stage can heavily impact on whether a statistically meaningful result is achieved. Various factors such as how the trial is conducted (dumping or purging the charge); the circuit configuration; collection of the right data; and even the human factor will affect the outcome. The authors will use examples to demonstrate the importance of proper planning and controlled operation on grinding media plant trials.

Jan 1, 2009

The treatment meIhods selected for the concentrator at Cobar Mines Pty. Ltd. called for a high degree of automatic control of both the grinding and flotation sections.The resulting concentrator layout includes a central control room overlooking both grinding and flotation sections. The control room houses process recorders, controllers, and indicators. together with motor stopstart stations and alarms.Plant instrumentation includes load cells and variable speed hydraulic drive feeders for feed-rate control of autogenous mills, together with nuclear density gauges, differential flow transmitters, and pneumatic control valves for water and pulp density control.Flotation cell pulp levels are controlled by floats and pneumatic actuators; flotation reagent controls include magnetic flowmeters and time-operated solenoid valves.

Jan 1, 1969

By T Galvin

Drilling and blasting at Westside Mine near Wallsend, NSW, has presented a challenge for Orica Explosives, Australia. The colliery produces 600 000 tonnes of steaming coal per year from two seams using surface mining techniques. Tapping into underlying coal will greatly improve the yield, but there are many issues which make this an enormous challenge. Hunter Valley Earthmoving engaged Orica Explosives to supply the explosives products and to provide much of the blasting expertise that is needed on the minesite. Hunter Valley Earthmoving and Orica Explosives have proven to be an outstanding, unified technical team on this project. The success of the team is based on good communication, progressive attitudes, extensive expertise in blast design and most importantly, care and accuracy in implementing the agreed upon designs.

Jan 1, 1999

Deep lead mining by methods other thanconventional open-cut techniques has not been effectively employed in Australia in -the second half of this century. The reasons for this are essentially economic, and are related particularly to the labour intensive nature of the methods involved as well as the high consumption of support materials. These methods have been adapted in recent times to undertake bulk sampling programmes in deep leads. Although some consideration is given to surface-oriented hydraulic and solution mining applications, the prime function of this paper is to investigate the possible application of modern underground methods to deep lead exploitation. As deep leads are not currently being worked (with the exception of some minor operations on the Eastern seaboard), these applications remain essentially untested. They have, however, been conceptually developed following several years of small scale deep lead development. Current mineral economics, particularly with respect to gold, combined with the known extent of partially - or totally - unexploited mineralised leads demonstrates the necessity to investigate all possible means of ore extraction.

Jan 1, 1985

By Schmidt LC

The method of supporting excavated roofs in underground coal mines by conventional roof bolting systems is challenged due to its shortcomings of being time-consuming and leading to possible unsafe installation. Though a few alternatives have been considered, the ultimate and most efficient bolting method has often been conceived as one using a self-drilling roof bolt, or a Rapid Face Bolting System (RFBS). The on-going Rapid Face Bolting Project undertaken by the University of Wollongong includes a special tubular bolt design.The tubular bolt designed for the RFBS is a "single-pass" bolt equipped with cutting tips used to drill a bolthole to accommodate the bolt. Different from that of the coring bit employed in geological site investigations, the principal design consideration for the tubular bolt is low cost associated with a small working life for the cutting tip.

Jan 1, 1991

By Mishra S. N, Mishra R, Sen P. K

Control of silicon in produced through the submerged-arc furnace can result in reduced power and coke consumption in addition to improving the quality of the hot metal. A thermo-chemical analysis of the production of ferro-chromium was carried out to devise strategies to control the recovery of silicon during the manufacture of ferro-chromium. The presence of three thermochemical zones in the furnace with respect to the reduction of silica was recognised from this analysis. Any strategy for the control of silicon recovery has to take cognizance of these thermochemical zones. The effect of various strategies on the silicon level in the hot metal have been evaluated. Possible strategies, such as the reduction of coke level in the charge; the replacement of quartz; pre-reduction of the ore and the control of the temperature profile are discussed in this paper.

Jan 1, 1999

By D Brennan, S Jahanshahi, F Jorgensen

The recycling of metals can be very efficient with careful selection of the material being recycled. The volume and value of recycled ferrous scrap has lead to the development of steel mini-mills which in turn has caused major changes to the steel industry. Although much smaller in volume, the recycling of lead is very significant, with battery recycling accounting for 60 per cent of annual world production. This high recycle rate can be attributed to the relatively uniform feed-stock from lead-acid batteries. The recycling rates of other metals are considerably lower due to longer use and non-uniform product usage that results in less efficient segregation and processing. It is clear that recycling of metals has advantages but its sustainability is uncertain. What are the key benefits of metal recycling? Metal recycling has technical, economic and social impacts. It is relatively easy to assess recycling on a technical basis, but the social impacts are harder to evaluate. This paper examines some of the issues in evaluating the sustainability of metal recycling.

Jan 1, 2002

By A B. Bell

The health and in some cases survival of mineral exploration and mining companies is, in today's markets, more dependant than ever on the effective use of information technology. The need for speedy collection, organisation, maintenance and distribution of corporate and project information is a phenomenon that will continue to strengthen with market thirst.Geographic Information Systems (GIS) provide a medium for storage, maintenance and retrieval of data, and Internet Mapping adds a technology for effective distribution of that data. Combining these technologies can return benefits both fiscally and technically by reducing costs of ownership in IT infrastructure and increasing the efficiency and effectiveness of both internal and external information delivery.GIS and Internet Mapping technologies have reached a practical stanza in their evolution and will continue to develop as a key business tool in the natural resources sector.

Jan 1, 2002

By D G. Miljak, J Khachan, B K. Schwitter

The performance of prototype magnetic resonance sensors suited to mineral measurement in conveyor, slurry or portable applications is described. The sensors can be positioned around conveyors and modified slurry pipes, providing deep penetration of the sensing field, relative insensitivity to ore surface conditions and high mineral discrimination. Measurements on slurry, concentrates and ores sourced from mine operations are presented for two applications. Firstly, the quantitative measurement of chalcopyrite in slurry was demonstrated in laboratory measurements. In a calibration test, a standard error of 0.1 wt per cent and detection limit of 0.3 wt per cent was obtained. Secondly, results were obtained for the discrimination of iron ore texture. Signals were readily observed using measurement integration times of seconds to several minutes, depending on ore material. The results demonstrate the feasibility of online quantitative analysis of selected minerals in processing applications using magnetic resonance.

Jan 1, 2008

Financial theory often takes some time to penetrate industry and when it does it can result in a paradigm shift in valuations and mental models. The Black Scholes option valuation was first published in 1973, although the authors were only awarded a Nobel Prize in 1997. The valuation of real options has been applied to the oil and gas industry for some time, however it has only recently been more widely applied to the non-oil, mineral resource sector. The use of real option valuation (ROV) for the valuation of marginal and short mine life resource projects is a more useful valuation tool than the conventional DCF, NPV valuation tool. The application of ROV has major implications for corporate strategy. It generally favours equity over debt funding and non-hedging over hedging. A retrospective assessment of the successful development of the Lennard Shelf Operations demonstrates the concepts of implementing real options and the value destruction of limiting operational flexibility through debt and hedging activities.

Jan 1, 2003

By Hannan JC

Consent to develop and operate a new coal mine in New South Wales (NSW) will be conditional upon a number of environmental controls. In NSW, applications for any new major development associated with coal mining are determined by the Minister for Planning and Environment. The environ- mental conditions placed on the development consent, the coal mining lease and the approvals, and licences under the pollution control legislation amount to a substantial component of any new project's commissioning considerations. The nature, scale and location of projects and the principles of pollution control on which conditions of State Pollution Control Commission (SPCC) approvals are based have a considerable influence on project planning. The design, construction and operation of coal mines in NSW has been progressively modified over the past 15 years, to incorporate increasingly stringent requirements for environmental management. These requirements are in turn, a reflection of a greater community demand for environmental protection.

Jan 1, 1986

By Dr Subagyo

The energy consumption for producing metal from ore is strongly linked to the chemical stability of mineral being processed, availability and richness of the ore, and process route. Energy efficiencies are particularly linked to the process route. The energy efficiency of high temperature operations vary considerably but energy efficiencies greater than 70 per cent are achieved for large-scale metal production. Low temperature processing through grinding, leaching and subsequent electrowinning use large amounts of energy. In particular, grinding and electrowinning suffer from low overall energy efficiencies. The physical chemistry of a new proposed low temperature route, reactive ball milling, is unclear but preliminary evaluations indicate that it is likely to suffer from high energy consumption. In conclusion, low temperature processing routes for metals generally consume more energy that comparable high temperature processing routes.

Jan 1, 2002

By Williams DJ, Battino S

The rapid crushing technique for the measurement of gas content of coal consists of accelerating the rate of gas desorption from coal by crushing. This technique allows the determination of gas content in the space of hours rather than days or weeks as required for the traditional slow desorption technique. The crushing technique is used particularly when gas content determinations are urgently required for mine safety purposes. The method is now routinely used in underground coal mines of NSW and to a lesser extent in QLD. Despite the rapidity and efficiency of this method, concerns have been raised upon the reliability of the method to deliver accurate results. Experience in Australia has shown that there is in fact some discrepancy in results between gas laboratories using the rapid crush technique. The development of rapid crushing techniques for seam gas content measurements in Australia and the main causes of variability in the gas content test results were investigated. The gas laboratories participating in the gas content testing were CSIRO Division of Coal and Energy, BHP Technical Services and GeoGas Pty. Ltd.

Jan 1, 1998

By P O. Andersson

Mining of sill pillars is more difficult than the ordinary mining. The sill pillar mining is performed under more difficult conditions and the mining of the sill pillar itself produces more problems; failure of the rock due to high stresses, difficulties in controlling the fill above, overall stability of the stope and special requirements on the technique for backfilling. Altogether this makes sill pillar mining technically difficult and often not profitable. A project was therefore initiated with the aim to increase the mineable ore reserve by making sill pillars mineable, both technically and economically. The project aimed at developing technique for already existing sill pillars as well as planned sill pillars. For the existing sill pillars a technique would have to be developed for mining beneath unstabilised fill. For sill pillars that would be created in the future, the most suitable mining method and methods of supporting or stabilising the fill in the stope above was to be chosen within the project.

Jan 1, 1998

The risks faced by organisations are part of a risk continuum. They can be evaluated in terms of hazard, uncertainty and opportunity as well as by the degree of influence they have on conformance, operating performance and strategic objectives. This paper discusses the application of risk management techniques for mitigating blasting hazards, reducing blasting output variability, and implementing blast improvement opportunities. Effective risk management practices can identify and evaluate risks across all levels of the continuum and can deliver realistic assessments of the likelihood and impact of risks on the companyÆs safety and business objectives. This paper does not attempt to present technical details about blasting, rather it aims to provide enough blasting context and examples so that the practical benefits of applying the risk management process to blasting can be fully appreciated. The topics discussed include: explosive management plan; statistical process control; quality blasting, rock-on-ground; Blast Management; Mine to Mill optimisation; and blasting information systems. The concept of a blasting risk management system employing a continuous improvement loop is also introduced. On reflection the insights presented should be extremely useful for observing and understanding which risk face has management focus at a mine site or for a blast site.

Jan 1, 2001

By M Warren

The professional geologist or engineer on a mining operation has a particular view of their operation. This is based on the factors of the operation that have a direct impact on the daily work program of the professional, such as production rates and grades. The view that would be taken by a financier who is called upon to support the project may be somewhat different. The value of the operation to the financier is in its ability to generate surplus cash for its owners and thus repay the debts to the financiers, with as low risks profile as possible. A number of tools are used to test the sensitivity of the project to variations in the key cost/revenue drivers. The Financier may call on a team of technical specialists to assist with the assessment of the cash flow and risk profile and to monitor the development of the project. The ability to offset this risk, as all projects have some degree of risk, may be a key factor in determining the level of financial support to be offered.

Jan 1, 2002

Mine haul road design at Bougainville Copper Limited has undergone significant changes since mine start-up. Selection of 95 tonne trucks and the subsequent replacement by 155 tonne units is discussed, with particular reference to haul conditions within the mine. Changes to haul road design and construction practices are detailed which have lead to improved standards and tyre life. INTRODUCTION Bougainville Copper Limited operates one of the largest copper mines in the world at Panguna, Bougainville Island, in the North Solomons group of Papua New Guinea. The mine commenced commercial operation in April, 1972 and current planned production is 198 000 tonnes of material per day, of which 115 000 tonnes is ore averaging 0.46% copper. Annual total planned production is 72 000 000 tonnes to yield approximately 150 000 tonnes of copper with significant quantities of gold and silver. The mine operations workforce now consists of national employees up to General Foreman level.

Jan 1, 1982

By P Allum

This paper presents a case study to reduce the operational cost on the secondary ball mill circuit in the Lead/Zinc Concentrator at Mount Isa Mines. The circuit includes two five-metre diameter ball mills each closed with a cluster of ten 15-inch cyclones. The operating cost for both ball mills is about six million Australian dollars per annum.The concentrator achieves 75 per cent of the plant design capacity with one ball mill operating, but will have to use two ball mills when 100 per cent plant capacity is required. The optimisation study on the circuit identified a new flowsheet that enabled the concentrator to reach 100 per cent of the capacity by using one of the two secondary ball mills. The success of the project utilised the existing equipment rationally and saved the operational cost for one ball mill at full concentrator capacity. A further simplified secondary circuit is proposed using the IsaMill for the secondary grinding duty. Performance of the IsaMill circuit and the potential cost savings are predicted.

Jan 1, 2002

By R Balusu

This paper provides an overview of computational fluid dynamics (CFD) modelling capability developed by CSIRO with the aim of improving the knowledge of flow migration dynamics within longwall goaf areas. The CFD models can be used to study the ingress of oxygen into the goaf in different ventilation scenarios and goaf drainage arrangements. This approach not only helps the design of effective gas control strategies but also the management of spontaneous combustion risk in the goaf. Innovative goaf inertisation strategies have been developed and implemented during longwall sealing operations. Work is continuing to develop general guidelines of proactive goaf inertisation strategies to suppress the development of spontaneous heating behind active longwall faces.

Jan 1, 2005