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The future of the Tasmanian mineral industry can only be estimated from a knowledge of the past, and armed with this knowledge an orderly plan for the future can be developed. Brief mention is made of the major historical developments through to the present day, with past and future development areas clearly mapped. Areas of importance which have been discussed are divided into the mining of metals, fossil fuels and non-metals; and the process- ing and extractive industries. Discussion then follows on the current general non-insular pressures on the mining industry, the energy crisis, scrap, world shortages, new techniques, inflation, and the effects of exploration on the environment. This is then followed by a discussion of the advantages of Tasmania as a mining state and a cataloguing of the present exploration and some possible areas of future development. From this a suggested plan emerges for the future development of the Tasmanian mineral industry, to incorporate the latest technological advances and by planning to meet the challenge of survival and growth in a turbulent environment.

Jan 1, 1977

Aluminium in Australia, and in fact all round the world, is made virtually exclusively by the Hall-Heroult process, whereby the metal is derived from the electrolysis of alumina dissolved in an electrolyte comprising fluoride salts. It is the distribution and control of these inorganic fluorides during and after the reduction process which go to make up the bulk of environmental problems associated with aluminium reduction smelters. The emission characteristics of fluorides from the process, the occurrence and effects of fluorides in the environment, and the control techniques wnich are applied in industry, all need to be taken into account in assessing the overall environmental aspects of aluminium Production.

Jan 1, 1977

The successful operation of diesel equipment underground does not entirely depend on selection of robust, reliable, easily maintained machines. Results are also heavily influenced by the following factors: Design and condition of the operating area. Skill of operators. Correct maintenance facilities. Experience, skill and initiative of maintenance personnel. If the mine layout does not allow access to a central workshop area, the effect of any shortcomings will be magnified. The best results will only be obtained by close co-operation between mining and maintenance departments right from the initial planning stages.

Jan 1, 1977

The curbing of expansion in tertiary level education in Australia and the question- ing of its objectives which are now occurring are likely to have important effects on mining and metallurgical education. Student enrol- ments are low but the serious shortage of specialised minerals industry graduates pre- dicted during the boom of the late 60's has not eventuated. Other manning problems of a less quantitative but possibly equally import- ant kind have been identified. They point to a need for a full and deep review of the education and training programmes available to Australian graduates planning to enter product- ion areas of the minerals industry. An alter- native educational structure providing greater flexibility is suggested.

Jan 1, 1977

By Penney B. K, Baghdadi A. A

An electron probe micro-analyser, controlled by a dedicated mini-computer,has been operating at Imperial College since 1970. The data assessment capability of the computer was limited and, in order to make better use of the information produced by the analyser, extra computing facilities were needed. Following the initiation of a Laboratory Automation Project at Imperial College involving the use of a central computer linked to laboratory type computers and to further more powerful systems,it became possible to carry out much more detailed and extensive mineralogical analyses by connecting the mini -computer to the Laboratory Automation Network. The paper describes the techniques employed including hardware, software, inter- connection, analysis and operating methods.

Jan 1, 1977

King Island is situated at the western approach of Bass Strait and approximately mid way between Victoria and Tasmania. The scheelite orebodies lie within the south east of the island. Ore bearing horizons from 10 m to 40 m thick occur in south and east dipping stratiform deposits. The orebodies occur in skarn formed by contact metasomatic replacement of carbonate rocks by granite intrusives. The scheelite is deposited as fine disseminated grains in and along the margins of andradite garnets in the skarn. King Island Scheelite operates two under- ground mines from which 350 000 tonnes per year are obtained. The Dolphin mine produces almost two-thirds of the total. See Figure 1. The Dolphin orebody lies beneath the sea and an area of reclamation. The orebody is inter- sected by zones of major dislocation. A chequerboard post pillar cut and fill stoping system has been chosen to provide the necessary support to the hanging wall. Because the stability of the pillars is critical to the economic welfare of the mine, considerable attention is given to the reduction of overbreak.

Jan 1, 1977

The Racecourse Orebodies at Mount Isa consist of a series of parallel steeply dipping lead/zinc/silver orebodies with a strike length of up to 1000 metres. Production from these orebodies between 13 Level to 9 Level has been by a series of cut and fill stopes in two level stages, leaving a crown pillar at 11 level. Development of the 15 level to 13 level extraction stage has recently been completed. The layout consists of a series of parallel stopes over a strike length of 1200 metres. Access to the stopes is by two declines connecting the stopes with a series of crosscuts This paper describes the basic layout with development and production methods employed.

Jan 1, 1977

By Blair J. R

In the Bayer process, bauxite is leached with caustic soda, forming a solution of sodium aluminate, from which hydrated alumina is precipitated. The efficient operation of the continuous form of this process requires that the concentration of caustic soda be controlled. A computer simulation of the concentration of caustic soda has been conducted to provide information, regarding the dynamic behaviour of caustic concentration, which is not available from normal plant data. The basis of the simulation is a state- space model of an alumina refinery, linearized about the normal operating condition. The formulation of the model, with the relevant approximations and assumptions, is outlined. The simulation of the mudwash section of the. plant is described in detail. A continuous model of the mudwash, having time-varying coefficients, was driven using operating data from an alumina refinery. The modelled response showed reasonable agreement with the recorded plant response.

Jan 1, 1977

The paper presents an algorithm for calculating the natural air distribution in a ventilation network (sub-network) on the basis of following data: - for each network branch: labels of starting and ending nodes, label of the branch, resistance and natural depression; - for each fan: the characteristic in the form of a second order equation and initial flow.

Jan 1, 1977

Renison Limited produces high and low grade tin concentrates at an annual rate of 5000 tonnes of contained tin metal. In spite of the fine average cassiterite grain size, emphasis is placed on gravity concentration methods to produce a high grade final product. Cassiterite flotation is considered and operated as a gravity circuit scavenger responsible for approximately 15 percent of recovered tin metal as a fine grained low grade concentrate. Metallurgical problems mainly result from ore-type variations which may be aggravated by a number of circulating loads. The rationalisation of circuitry is being studied to provide more effective control by operators and to allow exploitation of current control and modelling techniques.

Jan 1, 1977

An Ore Reserves and Exploration System has been under continuous development at Mount Isa Mines Limited since 1970. The task of re-engineering the system has now begun, and the first stage is operational. This paper describes how the application of data base concepts, and table driving techniques has resulted in a design in which the input documents, validation procedures and file data content are redefinable by parameters, thus allowing the system to be tailored to suit varying geological Environments.

Jan 1, 1977

By Miezitis Y

A weak airborne radiometric anomaly was examined in the field and the presence of uranium confirmed. Rotary-percussion drilling showed the presence of uranium but a subsequent programme of diamond and rotary percussion drilling indicated that the concentration of uranium was uneconomic. Within the tufts and volcanics of the prospect the uranium existed as uranyl phosphates within the oxidized zone. Geological mapping and the diamond drill core showed that the Stag Creek Volcanics are part of the Lower Proterozoic Masson Formation, probably with member status, rather than the expression of an Archaean basement ridge. This change in the interpretation of the fundamental structure of the Pine Creek Geosyncline has led to a reexamination of the stratigraphy and to suggestions which differ from the current concept.

Jan 1, 1977

By D E. Thorp

The mining and concentration operations of New Zealand Steel have been carried out initially from the Waikato North Head (WNH) deposit since 1969 and subsequently from the Taharoa deposit since 1972. Over the years the WNH operation has produced about 1.2 million tonnes of concentrate which has been converted into steel, while total exports to the Japanese Steel Industry from Taharoa reached five million tonnes in February of this year. Recent expansion plans both in domestic steel production and in the ironsand concentrate export market have made it necessary for the company to look closely at, among other areas, the mineral processing of the titaniferous ironsands in both deposits. This paper deals with the recent test work carried out at WNH and Taharoa on the use of the cone concentrator unit as a primary gravity concentrating unit ahead of the magnetic separation stages and as a cleaner concentrator following the primary magnetic separation.

Jan 1, 1977

The mineralogy and microstructure of mattes from the nickel flash smelter at Kalgoorlie, Western Australia, have been studied. The flash furnace matte consisted mainly of an intimate mixture of pentlandite and heazlewoodite with some nickel metal. The electric furnace matte was mainly an iron-nickel alloy with subsidiary pentlandite while the converter matte consisted mainly of heazlewoodite with crystals of nickel metal.

Jan 1, 1977

A model has been developed for the per iodical maintenance of bins used for hydraulic hoisting in mining of steeply inclining coal seams. This model gives a control plan for hoisting, bin switching and bin maintenance on a regular schedule.

Jan 1, 1977

ADDRESS BY THE PRESIDENT OF THE INSTITUTE (MR. J. G. SYMONS) IN PRESENTING THE CERTIFICATE TO ROBERT COLVILLE BRADSHAW, O.B.E.Today it is my privilege and pleasure to introduce to you, Robert Colville Bradshaw. O.B.E., the third New Zealander to be honoured with Honorary Membership of The Institute. Sir William Hudson and Mr. C. H. Benney were the others.Mr. Bradshaw has been an Affiliate Member of The Institute since the formation of the New Zealand Branch in 1966. Like his friend Matt Benney. Bob Bradshaw is an accountant by training. Last June he retired as senior partner of the firm of chartered accountants, now known as Wilkinson Wilberfoss, with which he served from January 1929.Mr. Bradshaw grew up in New Zealand attending the Terrace School in Wellington, the New Plymouth Boys' High School where he was a boarder, and completing a Bachelor of Commerce at the university now known as the Victoria University of Wellington. He is an elected Fellow of the New Zealand Society of Accountants and an Associate of the United Kingdom Institute of Cost and Works Accountants.

Jan 1, 1977

By Haigh C. J

A process has been developed to recover at least 75% of the 2-naphthol contained in cobalt precipitate produced during the removal of cobalt from electrolytic zinc plant solution. The recovered material is in a form suitable for recycling to precipitate further cobalt from solution. The process consists essentially of two steps. The first involves leaching of cobalt precipitate in 400 g/l sodium hydroxide solution at 95¦C in the presence of an additive. The second step involves treating the filtrate from the leaching stage with sodium sulphide to precipitate cobalt as the sulphide thereby re- generating the sodium hydroxide for recycling. The process is only marginally profitable at present 2-naphthol prices, giving a net return of 20% on a capital investment of $1 200 000. A reaction mechanism is proposed which accounts for the 25% loss of the 2-naphthol in the recovery process.

Jan 1, 1977

Conveyor belt haulage offers the advan tages of continuity of operation, minimum labour requirements, and the ability to handle large volumes of material over extended periods. However, breakdown of critical con- veyors in the system can cause undue and substantial losses in production output at the working faces, unless adequate surge bin capacity is incorporated in the haulage system. A conveyor belt simulation programme, code name 'Beltsim' was developed by Bucklen et al (1968) at the Virginia Polytechnic Institute in the U.S.A. and provides a quantitative measure of the performance of a conveyor belt network design. A limitation still exists with the computer programme and involves the inability of the programme to predict the necessary surge bin capacity to overcome conveyor belt downtime. The computer programme was modified to overcome this limitation, to simulate a con- veyor belt breakdown, and to provide a quantitative prediction of the surge bin capacity necessary to permit a modern mining system to operate effectively and continuously.

Jan 1, 1977

This paper presents a review of computer techniques for the automatic contouring of geological and geophysical data with output as interactive display on graph plotters or graphics terminals and passive display on automatic drafting tables. The advantages of the method of fitting a triangulated surface to randomly distributed data using an advancing front algorithm are described, as well as the technique for determining interpolated values for the production of contour line segments and a contour smoothing algorithm. This contouring method is employed by the Geological Survey of Queensland and is implemented as an interactive system. An alternative method ideally suited to randomly distributed data involves the use of piecewise parametric cubic splines. This method which is ideal for sharp variations in magnitude and areal extent typical of geophysical anomalies is discussed. The mathematics of surface interpolation using non-parametric splines and an explicit piecewise surface fitting technique are discussed. Curve tracing techniques which are suitable for automatic contouring are also presented and the inherent advantages of interactive contouring using on-line plotters and graphics terminals for previewing of displays are described.

Jan 1, 1977

By Sillet R, Corin P. J, Wilson G

Zinc Corporation of Broken Hi11 had some long hole stopes coming into use which could not be mined using diesel loaders, because of ventilation restrictions. In preference to use of pneumatic loaders, and because there were no field proven electric loaders in Australia, Horwood Bagshaw Ltd., were commissioned to repower a diesel loader with an electric motor, within the confines of the existing machine

Jan 1, 1977