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By J Shooter

Pezzimenti Laserbore designed, fabricated and commissioned the first microtunnelling machine in Australia in 1986. The System was initially a very basic one, developed in isolation to the overseas explosion in microtunnelling growth headed by Japan and Germany. Market needs in Australia have demanded increasing flexibility in microtunnelling capacity-longer distances, variable ground conditions and larger diameters. The one constant throughout the development process is in maintaining high accuracy û the attribute which most readily differentiates microtunnelling from other limited steering techniques.This paper will highlight the features of microtunnelling by drawing on case studies of completed projects.

Jan 1, 1999

Over the last five years the :forward momentum in the Australian resources sector has been dominated by gold production and exploration companies. While reporting of exploration results to shareholders and Stock Exchanges has generally been detailed and responsible, the standards of reporting ore reserves still leaves much to be desired in terms of contemporary investor expectations. Australian gold ore reserve reporting practices are critically examined and suggestions are made as to how gold mining companies can enhance stock market recognition by investors through more informative and useful Reporting.

Jan 1, 1987

The aim of the study was to determine the ranges of stability and instability of the metal hydroxides and metal cyanide species that may be formed during the gold extraction process, Merrill-Crowe gold precipitation, and Inco S02/Air or ferrous ion cyanide removal processes.Following cyanide detoxification by the Inco S02/Air process, the main components of concern in the tailings will be:

Jan 1, 1997

By Folie M

Energy models are evaluated according to their contribution to policy decisions. The view taken is that if any model is to provide policy insights, it should be based on economic theory. The difference in modelling methodology between economists and technol- ogists is discussed. The technique of energy analysis is criticised. The basic structure of some of the large economic models is presented and their policy usefulness is Discussed.

Jan 1, 1977

One major aim of the operation of Aberfoyle's matte fuming pilot plant was to assess refractories performance in the process working vessel, a SIROSMELT furnace. High wear rates were expected and whether these could be tolerated was an important question. During operations a range of refractory types was evaluated in both insulated and water cooled furnace designs. Furnace operations enabled lining wear measurements to be made. Results confirm that existing technology can solve any expected refractory problems. Design aspects that should be included in commercial furnaces are shown.

Jan 1, 1984

By Hunter M. M

The present value of the future profits of a mining operation, using a discount factor which represents the effective cost of venture capital, provides a measure of the projected success of the operation. The present value can be maximised by appropriate selection of cut-off grades successively through the life of the operation. A case study is presented in which detailed optimisation of cut-off grade results in a worthwhile increase in profitability compared with the use of a constant, break even, cut-off grade.Some implications of this approach to profit optimisation are discussed.

Jan 1, 1992

The perennial challenge facing mining and minerals operators is to improve productivity, usually by a combination of cost reduction and performance improvement. In a typical production situation involving mining and processing activities, the standard approach has long been to seek improvements in each activity, effectively in isolation from each other. However, the realisation is growing that there is considerable potential to achieve really substantial productivity gains by much improved integration of mining and processing with the key being to consider what is best in the total sense. Some of the linkages between fragmentation in mining and downstream processing are considered in this paper. These linkages involve technical, operational and economic Considerations.

Jan 1, 1997

By King CJ

The C.S.A. concentrator of Cobar Mines Proprietary Limited was expanded in 1974 to treat 80 000 tonnes of copper-lead-zinc ore per four week period. Jaw crusher product is fed to two par- allel primary autogenous mills followed by a secondary ball mill. Each mill operates in closed circuit with cyclones. Improved control of grinding rate and product sizing has been obtained from this circuit compared with the system of two parallel single stage autogenous mills. The main operational variables are des- Cribed.

Jan 1, 1978

By Smith T

Bacterial oxidation is often attributed with the advantage that a high level of gold recovery can be obtained at a relatively low level of sulphur oxidation. This is sometimes attributed to the bacteria "tunneling" towards gold inclusions, however it is often due to the presence of two or more sulphides of differing gold content which leach at different rates. Gold is liberated from the individual sul- phides linearly with oxidation. The distribution of gold between pyrite and arsenopyrite in two samples taken from a prospective gold resource was examined. The two samples showed differing responses to bacterial oxida tion and it was shown that this was due to differing intrinsic gold grades in the mineral phases and differing proportions of the minerals in the two samples.

Jan 1, 1991

The mineralogy of ten trihydrate bauxites and their leached residues from bomb digestion tests at 140, 180 and 2400C was investigated and the resultsòcorrelated with analytical data. It is shown that increased recovery of alumina at high temperatures is due to. the dehydroxylation of goethiteòrather than the presence of alumina monohydrates. The effects of aluminous goethite -on the interpretation of "available alumina". results-and normative analysis are discussed and it is concluded that,'cautionòmust be exercised in interpreting the results of bomb digestion tests in terms of alumina hvdrates.

Jan 1, 1973

Extensive personal experience in the USA and Australia has shown that Australians working in suitable work environments are capable of world-class performance. To build such work environments, mining leaders need to ditch two common management approaches that have not succeeded. Firstly, stop relying on traditional methods of trying to change people's behaviour simply by using communication alone to change attitudes and then change behaviour. Analysis of human behaviour explains why this approach fails in all industries. Secondly, stop trying to improve productivity by just running harder and increasing capital investment. Understanding work processes explains why this approach has limited success.

Jan 1, 1995

The Australian underground contract mining industry has grown from almost nothing 25 years ago to the point today where half the countryÆs underground mines are using contractors to produce their ore and do their development. This growth was driven by the need to change poor industrial relations and work practices in sectors of the industry, along with the needs of many small gold mine owners to preserve their capital by using contractors to do their mining. The industry is dominated by two major privately owned contractors with a number of other publicly and privately owned contractors making up the balance of the market. This paper discusses the important trends in the contract mining industry and the directions it may take in the next few years.

Jan 1, 2005

The mining activities on the North Mine leases have, over the years, followed the orebody from the shallower depths at the southern end of the lease as it continued northwards at progressively increasing depths.Commencing from the south end, in the early days small shafts were used to obtain access to the orebody at the moderate depths involved.

Jan 1, 1957

By Golledge P

Access to the vast volume of exploration data available in the Geological Survey Division of the Department of Mines would be impossible without the use of modern computing methods. These data are used by geologists in the early stages of exploration activity and methods of access to those data by the mining public are discussed. A regime of the Department's current hardware and applications software usage and possible future developments to enable more efficient processing of administrative matters and the production of maps using on-line graphics are included.

Jan 1, 1983

By Bertrand D. L

Although investigations into treatment of Mt. Keast (a hill of tailing) began as early as 1940, it was not until the Imperial Smelting Furnace (I.S.F.) was installed at Cockle Creek by Sulphide Corporation that its treatment became eooncmically feasible. Early investigations and milling operations which began in mid-1976, with their developments are described. Metal recovery involves sulphide flotation, oxide flotation and gravity techniques.

Jan 1, 1983

An algorithm is described which leads directly to a unique set of coal washing parameters which, in two or more parallel streams, will give maximum yield of product at a given ash. This occurs when all parallel streams are washed to the same incremental ash. This strategy is shown to offer a considerable increase in yield compared to the simpler strategy of washing each stream to the same sumulative ash.

Jan 1, 1987

I have the pleasure to present 6 excellent papers in this section all of major relevance to the mining environment of today where competing social, legal and monetary interests and their often complex interaction require serious consideration. This is particularly true today where huge fluctuations in commodity prices makes mining a perilous undertaking while the world increasingly are becoming aware of the serious threat that mans activities has on his environment. The 6 papers deal with such complex issues as safety in an underground environment; How to protect sensitive wetlands well into the next century; The enormeous waterproblems in China and conflicting dewatering/water supply needs; Disposal of contaminated water in sensitive areas and the dynamic interaction between mining companies and legislation.

Jan 1, 1988

In a coal mine there are many substances capable of ignition under certain circumstances, which can be placed in the following groups: ordinary combustible solids, dusts, liquids and vapours, gases, metals and plastics. There are many factors influencing ignition, including temperature, minimum ignition energy, particle size, explosion pressure level, rate of pressure rise, specific energy content and also explosive limit. Not all are applicable in every case. Frictional ignition of methane is an accident statistic of increasing concern and is considered in some detail. Practical measures that can be taken to reduce the incidence of frictional ignitions are considered, and also possible ways of ignition suppression.

Jan 1, 1981

Commercial pelletizing commenced in 1955 to agglomerate very fine concen- trates which could not be fed directly to the blast furnace. Extensive develop- ment has taken place and is continuing. There are now three main heat hardening processes in use. Plants are operating, or under construction, throughout the world capable of producing in excess of 125 million tons per year of pellets from concentrates or direct mined orefines. The Whyalla Pellet Plant, which commenced production in May 1968, is examined in detail to illustrate the general principles of pelletizing. This plant converts high grade iron ore fines into high quality pellets at a rate in excess of 2 million tons per year.

Jan 1, 1971

By A D. Farmer

Power ultrasound may be used in a number of ways to enhance the processing of minerals. It is both technically and commercially feasible to apply ultrasound to leaching processes in order to enhance the removal of contaminating minerals, or the rate and ultimate recovery of valuable mineral. When applied to the production of synthetic rutile from reduced ilmenite produced by the Becher process, its use proved beneficial to both the aeration and the final acid leach process. The enhanced performance is achieved through the very localised high energy release at the mineral surface from the collapse of cavitation bubbles produced by power ultrasound. This gives rise to two effects: initially, the rapid cleaning of mineral surfaces û of oxidation products and coatings of fine adhering gangue minerals û and the attenuation of the boundary layer at the mineral surface during leaching, which allows fresh leachant to contact the surface more readily.

Jan 1, 2000