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Australia has been a major exporter of LPG since production from the Bass Strait fields commenced in 1970. Export levels have been maintained through the seventies, the bulk of material being delivered to Japan. During this period the use of LPG in domestic markets grew only'slowly and demand was largely met by production from refineries with only shortfall supplies being drawn from naturally occurring sources. The domestic demand is forecast to grow significantly during the eighties as the traditional, automotive and petrochemical uses of LPG are expanded. An increasing amount of naturally occurring production will be directed into these markets. Despite this redirection the current level of exports (about 1.5 million tonnes per year) is likely to be maintained through much of the decade ahead as production from the Cooper Basin and the North West Shelf becomes available.

Jan 1, 1982

By Ellis CG

The N.S.W. Department of Mineral Resources commissioned its first Mobile Gas Laboratory in 1973.Although originally intended for diesel exhaust analysis, it has been progress- ively made more suitable for mine air analysis. Currently there are two upgraded units in operation. These laboratories have been used at the scenes of four mine fires, two mine explosions and three recovery operations. The authors' experience jointly covers all of these incidents. In this paper they recount the role of the Mobile Laboratory in each incident - including the difficulties encountered - and trace the development of these units to their present state. Future improvements are foreshadowed, and some comments offered concerning the likely future role of these vehicles in mine Emergencies.

Jan 1, 1981

By M D. Kuruppu

Fleet operational effectiveness is fundamental to any operation, becoming highly topical in mines experiencing less than optimal output from their fleets. It is an all encompassing aim to identify those factors that could be improved within production and suggesting solutions in order to optimise the existing fleet and obtain the highest return on capital expenditure. The fleet operational effectiveness of a large open pit truck and shovel operation in Western Australia was examined and a study was undertaken allowing identification of areas falling below target. The annualised hours and production downtimes were investigated to quantify the potential gains of improvements in these areas. The project aimed to maximise direct working hours through determination of the main issues hindering performance. External and internal factors were considered and a continuous improvement program (CIP) was developed. The CIP aimed at internal site-based improvement teams to identify and implement solutions for improvement on a day-to-day basis. Strategies were then identified for the implementation of the proposed changes.

Jan 1, 2003

By Bailey DJ

Loader cut and fill stoping was first used at New Broken Hill Consolidated Limited mine in 1966. The equipment used included single boom pneumatic jumbos for drilling up- holes, diesel loaders for ore removal and diesel utility vehicles for rockbolting and servicing. Since 1966, there have been many modifi- cations and changes both in the equipment and stoping method. Twin boom pneumatic or hy- draulic drilling jumbos have replaced single boom pneumatic jumbos, electric loaders have replaced diesel loaders, diesel forklifts have replaced utility vehicles and "'flatbacking" has superseded uphole stoping. Concurrent with this has been the introduction of cable dowels in stope backs which has enabled loader cut and fill stoping to be used more extensiv- ely than in the past. There are now six loader cut and fill stopes at both mines and this paper traces the evolution of this method outlining the reasons for changes in technique and equipment.

Jan 1, 1982

Underground mines in Australia and worldwide are extending to greater depths. The effect of depth brings a number of challenges to mining engineers including geotechnical, ventilation, haulage and selection of mining method. The main effects of depth from a ventilation perspective are increased heat and humidity leading to reductions in productivity, occupational safety and health issues and the potential for fatalities. Numerous approaches have been undertaken over the years to mitigate against these effects. In this paper a review of various approaches to improving climatic conditions at a number of mine sites worldwide is undertaken. From these case studies it is argued that for mines at depth with the potential for a climate problem perhaps an alternative design philosophy to the established design philosophy should be utilised. In conclusion, the paper proposes some simple rules of thumb for use in mines with climate problems or the potential for climate problems.

Jan 1, 2008

By N Ross, N Goldup

In recent years the heavy mineral mining industry has started to look more closely at the feasibility of mining moderate to high slimes deposits. During the initial stages of orebody evaluation the primary purpose of the pilot plant is to produce heavy mineral concentrate for metallurgical evaluation. Hence, generally little consideration is given to the disposal of the waste material (slimes and tailings). This paper suggests additional, simple, low-cost, tests that can easily be incorporated into an initial pilot plant operation. With this data a more definitive evaluation of available waste disposal options can be made during the early stages of the project. Thus, permitting better project focus and utilisation of resources. These tests include free settling of slimes, natural slimes drying and consolidation (undrained and drained), tailings stacking angles, and particle size distributions of input and waste streams, etc. The objective and method of each test is summarised, together with its relevance to possible waste disposal options. The results of this preliminary testwork can later be used to expand upon and define further tests for the second phase of pilot plant operations, which will enable a more definitive evaluation of a proposed waste disposal solution.

Jan 1, 2001

By Aalbers J. P A

The State Electricity Commission of Victoria (SECV) operates 13 excavators, 3 travelling stackers and 4 mobile slew conveyors in their three open cuts in the Latrobe Valley. The majority of these machines have been designed and constructed to a German design code current at the date of order. The SECV has always ensured that the machines were manufactured and erected to the appropriate standards. The SECV has a policy of having all machines inspected by an independent inspector every two years. These inspections are based on those carried out in Germany. The inspections have been carried out by inspectors from Germany who have the necessary experience to do similar work in German open cuts. Major faults found during the inspections have been repaired, however,the gradual breakdown of corrosion protection system has continued. The structures on some machines have areas of bad corrosion. This, coupled with wear on major mechanical equipment, would require an extensive outage to overhaul the machines. Refurbishment of Hazelwood Power Station will result in higher levels of production and extended life for the station. This will require improvement in the total output from Morwell Open Cut (MOC). To meet this increased coal demand, the open cut equipment will need to operate more efficiently and for a longer period of life.

Jan 1, 1989

By Goldie R

The use of options theory in business has become well established in recent years and is currently one of the most exciting areas of current finance research. The theory can be used to value levered firms, and streams of contingent payments. This technique also has very practical applications in the areas of capital investment analysis and the valuation of equities in the natural resource industry. The use of options theory has been well accepted and used for many years in the trading of commodity options and futures contracts, in banking and insurance and in other industries. It also can be used to value such diverse contingent claims problems as the income tax liabilities of the firm and share underwriting agreements.Its application to the more complex options, such as those present in the resource industry, is only now becoming known. This lag is, at least partially, due to the difficult mathematics involved in solving complex options problems. Another factor is the almost overwhelming abundance of uncertainties, such as grade, tons and other natural risks, which must be considered in the evaluation mining projects.

Jan 1, 1990

The activiltion of sphalerite with electrolytically generated copper ions from a copper electrode instead of the usual practice of the addition of copper sulphate was studied in the laboratory. A large surface area of copper was provided by lining three sides of a bench flotation cell with copper sheeting. The lining was connected to the positive terminal of a low voltage d.c. source, and the cell impeller to the negative terminal.Sphalerite was effectively activated by this arrangement and was subsequently floated using xanthate as the collector.Flotation results comparable to those obtained with 1 lb/ton CuS04.5H20 (0,255 lb/ton copper) were obtained using 0·1062 lb/ton of electrolytic copper and 0·488 kWh of electrical energy. The wastage of copper due to the formation of insoluble precipitates was found to be dependent on the length of time the current was passed. Maximum current was passed for the shortest time to minimize wastage.

Jan 1, 1973

Computer programs for the storage, retrieval and use of basic thermodynamic and physical property data for chemical substances are described. Methods are presented for the collection, critical assessment and pre- processing of source data for files containing enthalpy, entropy and heat capacity data for 3000 compounds, enthalpy and excess entropy for 200 dilute solutions and critical propert- ies and vapour pressure for 600 compounds. Retrieval programs are discussed which allow the tabulation or plotting of many basic and derived thermodynamic properties for chemical substances or balanced reactions. Examples are given of the use of such data to infer the stability or corrosion resistance of materials and the feasibility, yield and heat release of reactions. A general purpose calculation program is discussed which allows the equilibrium compos- ition to be found for complex systems with many species and phases, using the method of Gibbs energy minimization. Methods of correction for non-ideal behaviour in these systems are discussed, as well as methods for fixing, maximizing or minimizing any desired property of the system. Examples are given of the simulation of various laboratory Experiments and industrial processes by this method.

Jan 1, 1977

By Gochin RJ

This paper focuses on measures of the economic significance of mineral exploitation and processing activities, such as beneficiation, refining and smelting. Empirical measures are suggested to quantify the relevance of the degree processing within a nation's mineral industry. The most useful, based on the input-output econometric framework, are used to establish the magnitude of links between the mineral industry and its satellite activities and for the appraisal of large, non-marginal projects. The input-output impact analysis is refined to allow for country specific behaviour and synthetic indices for the appraisal of investments in the mineral sector are developed. These indices are further improved with the introduction of shadow prices to incorporate socio-economic issues. They are useful to direct mineral policy decisions and several investments towards the most promising objectives for national goals. Finally traditional methods for the appraisal of small scale, marginal, mineral projects are assessed where local impact and regional development issues are more relevant than national ones.

Jan 1, 1993

The aim of all modelling is to replicate geological reality as closely as possible using available data. This paper is aimed at one end of the spectrum, where very limited data is combined with intuitive geological ideas to synthesise models for either target definition or for determining minimum viable mining scenarios. Interactive 3D modelling allows a satisfactory hypothetical geometry of surfaces to be assembled, and provides a fast quantitative method for generating targets. As data flows from exploration, an evolving geological model assists with the progressive evaluation of a prospect. Two case histories are described where this approach has been used successfully, the Mosquito Hill Prospect in Queensland and the Longwood Ranges Platinum Prospect in New Zealand. The possibility is also discussed of hypothetically modelling an orebody which has yet to be discovered. The proper description of an orebody is the foundation upon which all mine design and planning is undertaken. The volumetric accuracy of the model is crucial in valuing an orebody. Geologists must form a geometry which matches the conceptual view of the ore occurrence and ensure that they understand how the computer system used calculates volumes. If the underlying assumptions inherent in the method conflict in any way with the conceptual model visualised for the ore occurrence, then that method must not be used.

Jan 1, 1995

By Quinn P, Robertson G, Agar GE

The replacement of diphenylguanidine (DPG) for separating INCO Bessemer matte with a water soluble collector requires a frother since most collectors do not have frothing properties. The objective of this study was to identify a non persistent frother which produced a deep froth and collapsed rapidly, while maintaining acceptable metallurgical separation. Incremental rougher flotation tests failed to differentiate any metallurgical benefit through the use of a specific frother, so other tests were employed to identify the candidate frother. The equilibrium froth height and rate of froth collapse (froth stability) of several commercial frothers were evaluated as a function of frother concentration using a 'frothmeter' apparatus. Frothers evaluated were methyl isobutyl carbinol (MIBC), Pine Oil, triethoxy butane, Dowfroth SA1263, Dowfroth 250C, Dowfroth 200 and Allied Colloids CRNI-1002. Dowfroth SA1263 produced the largest froth height, and TEB had the greatest rate of froth collapse. Frothers with properties similar to Dowfroth SA1263 and Dowfroth 250 were rejected due to their persistent froths. TEB was rejected because it has a low flash point and Pine Oil could be a nuisance to add to a flotation column. Therefore, the preferred frothers were declared to be Dowfroth 200 or Allied Colloids CRNl-1002.

Jan 1, 1993

Gold bearing sediments at Scotland Point occur within the Quaternary Gibbston Fonnation, which underlies Cromwell Flat in Central Otago. Gibbston Fonnation unconformably overlies Teniary Manuherikia Group clays, sands and quartzose gravels. Gibbston Formation sediments are composed of a texturally diverse, multistoried lithostratigraphic succession of sandy/gravelly/bouldery lithofacies, deposited within a multiple channel (braided) depositional environment. Lithostatigraphic analysis indicate an upward overall decrease in average grain size, reflecting a concomitant reduction in stream competence. This trend results from progressive channel abandonment as major distributaries avulse across the outwash plain. Grade distribution of alluvial gold is controlled by aggradational and to a lesser extent degradational lithofacies deposited as distinctive braid bar forms near the base of the sequence. These lithofacies were deposited at different topographical levels on the outwash apron, under variable hydraulic conditions. Recognition of large-scale auriferous bedforms within the braid bar depositional system coupled with an understanding of lateral facies relationships, allows headgrade control on run of mine ore and quick determination of overburden to ore ratios.

Jan 1, 1988

AustraliaÆs current interest in renewable energy is based on a desire to reduce the countryÆs greenhouse gas emissions. Wood from sustainable sources offers a unique opportunity to combine greenhouse gas benefits with other significant environmental and social benefits, including salinity mitigation, carbon sequestration, soil replenishment and rural industry. The challenge is to make renewable energy from wood in a cost competitive manner, so that this broad range of benefits may be best realised. Bioenergy and carbon products are of great interest as new, commercial forestry products that can drive large-scale environmental tree planting:In Western Australia, Enecon has worked with Western Power Corporation to build the first full-scale plant for integrated processing of mallee eucalypts, to produce activated carbon, renewable power and eucalyptus oil. It is intended that this plant is the first of a number of such plants to help catalyse environmental tree planting in Western Australia. New technologies being developed overseas may provide competitive bioenergy in areas where traditional markets for wood do not exist. For example, pyrolysis converts wood into a bio-oil that may be transported to remote sites for power generation in gas turbines. Pyrolysis also produces wood char. Pyrolysis and wood-to-ethanol technologies, coupled with short rotation coppicing trees, offer the long-term prospect of large-scale production of renewable fuels around the country.

Jan 1, 2006

By Sturgul J. R

A major electricity generating authority have a proposal to construct a Power Station. An understanding of the operation of the bunker system is of importance to the designers and a computer simulation model of the operation was constructed. The computer language used was GPSS/PC which is a recent form of the language designed for the per- sonal computer. The model simulated trains arriving at the power sta- tion and unloading onto conveyors which carry coal to the power station bunker. Coal was drawn from the bunker at a specified feed rate to the power station. Numerous restrictions were placed on the model, if the bunker level got too high dozers would pull coal out of the bunker onto the stockpile, and if the level got too low the dozers would push coal back into the bunker. The conveyors and dozers were unavailable due to breakdown'at various times and trains would arrive randomly about a mean interarrival time. The system was simulated for 30 years of oper- ation and the model used a basic time unit of 30 minutes so that the system was updated 525,600 times during the simulation. The results of the simu- lation gave the designers a greater understanding of the critical factors in the operation, which may now be engineered to minimise adverse Effects.

Jan 1, 1988

By Rolley P

In the course of reviewing grade control practices at the Marvel Loch gold mine in Western Australia in 1992, FSSI Consultants developed and implemented a novel approach to ore selection using a method to maximise financial return (the MP method*). The approach was based on improved grade control sampling and an ore selection method which directly incorporates both a measure of the uncertainty in knowing the true grade of selection units in the definition of ore, as well as the operating cost and revenue parameters of the mining operation. During the past four years, FSSI Consultants have evaluated and refined the use of this approach and have implemented customised variations of the MP method at seven gold mines and a gold-copper mine in Australia. The previous methods of ore selection at most of these operations were based mainly on polygonal - sectional methods of grade estimation. At all of the sites where grade control optimisation has been given a fair trial over several months of production, the use of the MP method has been consistently rewarding to the mining operations. The benefits include increased run of mine ore stockpiles and low-grade stockpiles and decreased fluctuation in the production grade. Most operations have also benefited from a consistent ability to improve production grade through high-grading of the increased ore production. The increase in ore production has the logical benefit of reducing stripping ratios, increasing mine profitability and mine life.

Jan 1, 1997

Until 1937, the mining of ore was carried out by conventional methods, using pneumatic drills and standard drill steel. The adoption of the diamond drill, formerly used for exploration work, for blast hole drilling in stopes, was first developed by Noranda Mines Limited, Noranda, Quebec, although it had been used previously in Northern Ontario and Western United States, to remove weak pillars and ore remnants left by conventional methods. Previous to the adoption of the diamond drill method at Noranda, a sub-level benching system of stoping was used. Sub-levels were driven at 35 ft. intervals and the benches drilled off by pneumatic drills using sectional steel. Results were very satisfactory, in sulphide ore, where the drilling was comparatively easy, but in the harder rhyolitestopes the footage drilled per machine-shift was only half of that obtained in the sulphide stopes, and owing to the high gauge loss, there was often difficulty in drilling holes to the required depth. This led to trials with the diamond drill for this type of work. While the cost per foot was more than with sectional steel, an appreciable saving in development work could be made by increasing the sublevel interval from 35 ft. to 60 ft., and stope widths from 60 to 100 ft. This saving, together with the increase in blasting efficiency, resulted in a substantial reduction in overall costs.CONDITIONS FOR SUCCESSFUL APPLICATIONWhile long diamond drill blast-hole mining has widespread application, there are certain conditions which appear to be desirable, if not absolutely necessary, for its successful use.

Jan 1, 1946

I began my interest in sample preparation when I joined the Institute of Nuclear Sciences in 1962. I worked in the fields of rock dating and stable isotope geochemistry. Preparing a sample could take several days and the analysis took another day or more, so great care was taken with each sample. In 1968 I changed to mineral exploration analysis and was surprised to find that there was much less care in how a sample was taken and prepared. Virtually every sample was processed in the same way. In the use of ring and puck mills, Australia and New Zealand were among the world leaders. It took another ten years before labs in North America changed over from disc mills. In 1975, my partner and I divided our business into two parts. He took the laboratory into his consulting laboratory business and I took the small business that we had started, making ring and puck mills. For the next six years I was RocklabsÆs only employee. In the 1980s and 1990s, sampling specialists like Francis Pitard and Dominique Francois-Bongarcon began to make a difference in the understanding of what constitutes good sampling and preparation practice. They and others took courses on the new concepts of Sampling Theory, as developed by Pierre Gy. The desire for better procedures lead to the development of new machines, including the big bowl pulverisers from Australia, jaw crushers that could crush finely like our Boyd Crusher, rotating dividers of new designs and flow-through ring and puck mills. Other machines did not fare so well, including rolls crushers, cone crushers and hammer mills.

Jan 1, 2008

By M Freeman

Significant improvements in the metallurgical performance at Pasminco Rosebery Mine have occurred over the last two years. Lead and silver recoveries have increased by more than ten per cent, lead concentrate grades are four per cent higher, zinc recoveries are up 1.5 per cent, and zinc concentrate grades have increased by two per cent. These impressive results have not occurred through the application of some new wonder reagent, but through the application of some fundamental metallurgical principals. The basic premise applied during this study was that to make an effective separation you must first achieve liberation. Therefore, the laboratory and plant studies examined the liberation characteristics within the lead circuit, and the impact of regrinding. The work demonstrated clearly that galena/sphalerite liberation was poor, and significantly impaired plant performance. Further, it was suggested that the application of lead regrinding of the lead scavenger concentrate and the lead first cleaner tailing would not only benefit lead metallurgy, but also improve sphalerite flotation. A similar approach was then applied to the zinc circuit. From these studies, solutions applying simple circuit changes utilising existing equipment were proposed and implemented. Further to the improvements in galena/sphalerite liberation, significant improvements in concentrate quality were achieved by reducing variation within the process. The implementation of changes in work practices negotiated in the Enterprise Agreement, employee contributions and specialist training also made a significant contribution to the unprecedented improvement in the lead and zinc flotation circuit performance. The results of these plant changes are discussed, along with the suggested scope for further improvement.

Jan 1, 2000