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By Whiteman P. C, Stacey G. S, Hunter G. D

Processing of lead-zinc and copper ores by Mount Isa Mines Limited produces large quantit- ies of concentrator tailings waste which is pumped as a slurry to special dams where the solids are allowed to settle and dry out. These areas are unattractive and show no signs of encroachment by plant life even though the surfaces of some dams have remained undisturbed for more than a decade. During 1970 Mount Isa Mines Limited commenced a long term research program in conjunction with the Department of Agriculture, University of Queensland to deter- mine possible methods of establishing a plant cover on this material. Research has defined the major factors limiting plant growth in the tailings medium. Modification of the edaphic conditions through fertilizer inputs, particularly of phosphorus and nitrogen, and alteration of "soil" physical properties by incorporation of mulching mater- ials, provided conditions which allowed plant growth. The outstanding "soil" amendment treatment was incorporation of fly ash, a waste product of the company's coal fired power stations. A range of crop and pasture species have been selected which have grown well with adequate irrigation under the amended conditions in the field. Further research is assessing a range of native plant species and agronomic techniques to provide a stable plant cover on the tailings dams.

Jan 1, 1974

By Casley G. E, Pritchard J

A single slurry fed fluosolids roaster was chosen to replace six multiple hearth roasters in the Copper Smelter at Mount Isa as part of the overall program to increase production from 100 000 to 155 000 tonnes blister copper per annum. The paper describes factors influencing the choice of the unit, problems encountered during the commissioning and details of the present roaster operation.

Jan 1, 1974

By Stevenson C. H, Lynch A. J

The reasons for choosing autogenous grinding for the new Warrego concentrator of Peko Mines N.L. are discussed and the ores to be treated in the concentrator are described. The mill was designed on the basis of pilot tests carried out at Cobar and the performance of the mill has been most satisfactory both in its metallurgical and mechanical aspects. An empirical technique has been developed to predict mill performance for change in feed rate or feed size and a mathematical model of the mill is being developed for simulation and control work. The weight and size distribution of the mill load was determined at one set of operating conditions for use in the mill model.

Jan 1, 1974

The considerations which led to the decision to_ install discs at the Dampier Pellet Plant of Hamer ley Iron Pty. Ltd. are described. Initial testwork showed that the ore could be ground dry in open circuit to a Blaine index of 2500 cm2/g and that it pelletized readily. The various design criteria including diameter, slope, speed, motor size, depth of sidewall, feed point and water spray location were then determined. Plant performance after commissioning is described including the various problems encountered and the modifications since carried out to overcome them. The main problem was quickly identified as disc feed rate control. Various bin and bin feeder modifications were tried to overcome the effects of the fluidising characteristics of the dry ground ore. Other factors found to affect disc operation are ore size distribution, additives and operator competence.

Jan 1, 1974

By Kerr M. H, Slaughter P. J

Design of the new cemented hydraulic fill plant was based mainly on experience with a succession of previous fill plants. Two stage cycloning of combined concentrator tailings was introduced. Design of the two stage cyclone configuration was assisted by computer simulation of cyclone performance. Cementing additives, namely Portland cement and ground copper reverberatory furnace slag, drawn from bulk storage, are pre-slurried prior to mixing with hydraulic fill. Quality control of fill being sent under- ground is achieved by a series of automatic control loops. Plant instrumentation was given prime consideration during the design phase. Inventory checks of all mass flow metering equipment are made at regular intervals. Fill is pumped to boreholes at several locations. Details of the equipment and operating procedures for the plant are Discussed.

Jan 1, 1973

By Quadrio J. S, MacHunter A. M W

The initial development fl6tation testwork on Mt. Windarra op was completed on composited drill core intersections at the.Australian Mineral Development Laboratory. An exploratory winze provided samples, from the 130 M. level of the Mt. Windarra mine, for pilot plant and bench development tests. A limited test programme was initiated on the South Windarra drill core composites. Detailed mineralogy has been completed on selected samples from both ore deposits.

Jan 1, 1973

A sequence of ultramafic units, very well exposed in Munro township in the Abitibi areal, of the Cahadian Shield, exhibit features which indicate that they are sub-aqueous extrusions. They occur within a sequence of tholeiitic pillow lavas, thin graphitic sediments. and large differentiated sills. The units range from a few metres to more than 250 m in length and less than 1 m to over 30 m in thickness. Over 60 individual units, occurring as flat pancakes on top of one another, make up a total exposed thickness of 150 m. The units have formed from a magma composed of a very olivine-rich picritic liquid carrying up,to 40 per cent olivine phenocrysts in suspension. Different units display a variety,of cross-sectional profiles. As an example of the most extreme type of profile, a typical unit 2 m thick consists of a cap of highly jointed fine-grained quenched rock, 10-30 cm thick, which becomes coarser downwards, grading into a zone composed of radiating and criss- crossing skeletal olivine crystals forming the well-known spinifex texture. This becomes even coarser-grained downwards, with "books" of parallel platey olivine crystals developing sub-perpendicular to the plane of the units. Beneath this zone, which may be up to 1 m thick, there is an abrupt transition to a cumulus-textured rock composed of rounded

Jan 1, 1973

This paper deals with the extension of Post Office telecommunications (telephone, data, leased private lines etc.) network to mining communities in remote areas of Australia. The evolution of the "Spur Line" policy and its application is referred to together with comments on the engineering of telecommunication Facilities.

Jan 1, 1973

The highland region of Papua-New Guinea is relatively rugged terrain where stream gradients are steep. In areas where porphyry copper deposits outcrop the streams commonly expose primary sulphide mineralization in unoxidized rocks. Stream sediment geochemistry combined with float examination and broad geological mapping proved to be an effective tool for detection of outcropping bodies of mineralization. After discovery, detailed stream sediment sampling, soil sampling and rock chip sampling, together with detailed geological mapping proved adequate to delineate drilling targets. Reconnaissance stream sediment sample density was dictated by geology and access and a density of one sample per 25 Km2, or less, was desirable to ensure a high degree of confidence in the programme. Research indicated that the base metals occur in sulphide form in stream sediment and that the -80 mesh size fraction gave the most reliable results. The evaluation of results from any one area relied on the interpretation of the local geology. Basic histogram methods for determining background and threshold values for metals in stream sediments were

Jan 1, 1973

By Newman H. A

Goldsworthy Mining Limited is currently mining iron ore at an annual rate of 7 million tons from several small orebodies, each of which exhibit wide variations in iron, phosphorus, silica and alumina contents. Each orebody is mined at its average ore reserve grade and therefore mine planning and grade control techniques have had to be tailored to achieve a constant production blend.

Jan 1, 1973

By Lowder G. G, Cooper R. S, Radke F, Watmuff I. G

During the past five years Amdel has in vestigated metallurgically and mineralogically most of the Western Australian nickel sulphide ores. The mineralogical work has been carried out primarily to assist the metallurgical stud- ies and this paper reviews the application of mineralogical techniques to such ores to obtain information of direct use to the process met- allurgist. The techniques are described briefly and results are given of various in- vestigations of head samples, concentrates and tailings.. It is demonstrated that mineral- ogy has an important role to play in the optim- ization of nickel processing operations.

Jan 1, 1973

Petroleum exploration is proceed ing in Western Australia at an ever- increasing pace. Results in recent years have been very successful, with the discovery and development of the Barrow Island oilfield and the Dongara gasfield, and the discovery of several major gas-condensate fields on the Northwest Shelf. The Northwest Shelf discoveries will have a big impact on the economy of the State by providing an abundant indigenous source of energy. Prospects for further large dis- coveries are believed to be excellent. The most prospective areas are thought to be on the continental shelf in the Carnarvon, Browse, Perth, Canning, and Bonaparte Gulf Basins.

Jan 1, 1973

By Russell F. M

Following the accident in the Peterson section of Mufulira mine in September, 1970, a method had to be found of extracting up to 300 000 tonnes of ore per month from this area without inducing caving. Sandfill mining methods were chosen, necessitating a plant capable of producing both cemented and uncemented fill on a large scale. The paper covers the design and construction of this sandplant which is thought to be unique for its size, as it incorporates three 3 000 tonne capacity settled storage silos, a 500 tonne capacity cement silo, mixing tanks and a control room situated underground. The plant is designed to handle an aver- age of 440 tonnes per hour with a maximum of 660 tonnes per hour for limited periods, delivering either uncemented fill or cemented fill in proportions varying from 1:6 to 1:30. The instrumentation and equipment necessary to give one man operation of the plant is described and the fill mining methods now in use at Mufulira are briefly outlined.

Jan 1, 1973

By Palmer W. T

The successful re-opening of the Cobar min- eral field was dependent upon the success- ful introduction of highly productive, low cost mining. Mechanised cut and fill stop- ing with incline access was selected for the C.S.A. mine because it permitted flexi- bility, complete primary extraction with no secondary pillar recovery, minimised dilu- tion and oxidation, a minimum of pre-pro- duction development and because diesel powered load-haul-dump (L.H.D.) units were proving reliable and highly productive in the U.S.A. Although L.H.D. vehicles are the key to the success of the mining method, four other main groups of vehicles are utilised in the mine - trucks, scaling vehicles, ser- vicing vehicles and specialist vehicles. The operating requirements at the C.S.A. mine are more stringent than those encount- ered in many other underground mining oper- ations. The first L.H.D. vehicle used at Cobar - the Transloader - had considerable difficulty in loading and discharging coarse production ore. The Wagner ST5 Scoop Tram performed this duty much better. However, the first generation Scoop Trams were not robust enough to withstand the heavy duty and many modifications were necessary before acceptable availabilities were obtained. Similar modifications were necessary for the Eimco 916 vehicle but the Eimco 915 unit came much closer to meeting the duty requirements. Eventually Cobar technical personnel design- ed a L.H.D. vehicle to meet specific C.S.A. mine conditions. These units have proven most satisfactory. Over 8 years of operation the underground vehicle fleet has become a proliferation of vehicle types. A standardisation pro- gram has been initiated based upon common prime movers being mated with "trailer" units to serve specific functions. Standardisation will reduce inventory levels and facilitate training of operating and maintenance personnel.

Jan 1, 1973

The characteristics'of the Darling Range bauxite deposits are compared with tho"se of other large deposits in Australia and over seas The Bayer Process is them described with particular reference to the way.in which the process has been adapted to suit Darling Range bauxite. The.main characteristics considered are the physical aspects of the deposit.and its' effect on mining techniques, the grade of the ore and its effect on residue treatment, the nature of the alumina, iron and silica. content and their effect on process methods, equip- ment and raw material. Usage.

Jan 1, 1973

A unique set of circumstances has devel oped in the Mt. Newman Mining Co. Pty. Limited's project in the Pilbara because the mining town of Newman was built almost entirely by the Company whereas residential areas built by the Company at Port Hedland were developed as an adjunct to an existing town. The following discussion points out the different problems which have been developed in the two areas, even though basically the stand- ard of housing and general amenities is the same, and the means taken to overcome these Problems.

Jan 1, 1973

By Armstrong G. J, Bowling K. McG, Gray C. H

An experimental induration facility has been developed and used for conducting iso- thermal tests and plant simulation studies on the thermal induration of iron ore pellets. The influence of time, temperature, lime content, ore type, shale content and particle-size dis- tribution (e.g. Blaine Index) is being studied in a continuing programme. The present paper deals with experiments relating to the first three of these parameters and illustrates the use of an experimental design suitable for statistical analysis. The relations between isothermal data and the results of complete simulation rests are discussed.

Jan 1, 1973

In a field test at Mount Isa Mines Ltd., a system developed by ICI Australia Ltd. for bulk loading "MOLANITE", an ammonium nitrate slurry blasting agent into ring drilled holes of wblcvel open stopes, was shown to be satisfactory. The fragmentation produced by the slurry was a significant improvement over ANFO and the stope production rate was increased by approximately 50%. Indications are that the charging rate and labour costs will not be greatly changed if a slurry system is used.

Jan 1, 1973

The low grade Mount Charlotte orebody was first mined with minimum capital expenditure by mechanised cut and fill stoping. The lower block was prepared simultaneously for open stoping by shaft sinking and installing another crusher and services. Similar development for the third block was discouraged by economic factors and reduced tonnage. Decline develop- ment required less capital and opened up ore reserves commensurate with advance, providing flexibility to stop operations without commit- ment: A 1 in 7 decline measuring 4.25m x 5.5m to accommodate standard Euclid 25 tonne dump trucks was developed south of the orebody. A fleet of four trucks average 12 loads each per shift over a haul distance of 700m.

Jan 1, 1973

The seminar had its origins in an Inquiry into the Box Flat Disaster and one of the conclusions from this Inquiry was that there should be a better dissemination of technical knowledge and the results of research work. As a result of this Mr. W. Roach, Chief Inspector of Coal Mines in Queensland and Mr. R. Menzies, Chief Inspector of Coal Mines in N.S.W. had a meeting to see how this could be done. They concluded that it would be difficult to have the sort of regular meetings that would be possible where distance was not significant, but a seminar would be a major step toward satisfying this particular conclusion of this Inquiry. As a consequence, Mr. Roach, who is on the Committee of the Southern Queensland Branch of the Institute, suggested when the Branch programme was being planned this year that a meeting of this type should be held, and the Mine Fires Seminar which was held today is the result. We have received a great deal of support in arranging the Seminar. First and foremost I wish to acknowledge support from the National Coal Board in United Kingdom. Not only have they released Dr. Willett for a period of six to seven weeks to visit Australia, conduct the Seminar and give a series of lectures in various areas through the country, they have also borne the brunt of the financial support that has been necessary to make this possible. In addition we have received considerable support from many organisations in Australia. I 'mentioned this

Jan 1, 1973