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By Voermans F. M, Hoyle M. W H

The Archean geological sequence in the West Pilbara region (Fig 1), a deformed greenstone volcano-sedimentary succession regionally intruded by layered mafic/ultramafic lopoliths, batholithic granites, granite stocks and transected by swarms of dolerite dykes, has prompted several companies to search for a variety of base metals and and platinoids (Fig 2). In the first instance, detailed aeromagnetic surveying was completed, producing patterns of marked magnetic anomalism which proved substantially successful in the demarcation of areas warranting geological reconnaissance and detailed follow-up. Revelant to this paper were the obvious magnetic features overlying outcropping and buried mafic/ultramafic bodies which ultimately were proven to be host to Ni-Cu sulphides, pgm, Ti, V, Cr and, more recently, Ag and Au mineralisation. Routine stream sediment, soil sampling and ground geophysical techniques of the day appear, in most cases, to have been adequate in the detection of mineralisation, except in the case of Radio Hill massive sulphides where the Turam E.M. (1972) signal essentially failed to detect the blind conductor (Peters, de Angelis 1987).

Jan 1, 1988

By Collins D. N

The Olympic Dam Copper Smelter Acid Plant is a hybrid plant capable of producing sulphuric acid from either sulphur burning, metallurgical gases or a combination of both. Commissioning of the Acid Plant on sulphur burning commenced in early April 1988 and commissioning on combined sulphur burning and metallurgical gas commenced in August 1988. During commissioning on sulphur burning a number of acid spills occurred due to balancing of tower flows and control of acid dilution. A number of other significant problems were encountered including failure of boiler gaskets, failure of strong acid pumps seals, the fracture of the teflon dilution water injector and the subsequent failing of the acid circulation pump, tank steel failures and various instrumentation problems. The Commissioning of the Acid Plant on metallurgical gases commenced in August and with the exception of the production of oleum in the boiler economizer was relatively trouble free. Oxygen Plant commissioning commenced in May 1988 and was without significant incident. An outline of the basic equipment for the Acid Plant and Oxygen Plant is presented together with aspects associated with the commisisoning of both plants.

Jan 1, 1989

In late 1987 it was recognised that column flotation might have potential for improving the grade of the zinc concentrate produced at Pasminco's South Mine in Broken Hill. Intermittent test work was carried out during 1988 using a 90 mm diameter by 6 m high perspex column, built and initially operated by staff from CRA Advanced Technical Development. This column was found to have insufficient retention time so, during the first half of 1989, Pasminco constructed and installed a 200 mm diameter unit of the same height. Extensive testwork was carried out using this column during the latter half of 1989 and early 1990. It was clear from the results that a grade improvement of between 1 and 2 per cent (absolute) would be achievable. The effect of column cleaning on overall recovery was not established with the same degree of confidence, so the proposed new circuit is to include one of the existing banks of OK8 cleaner cells as a scavenger on column tailings. The test work provided sufficient data for preliminary design work to begin in May 1990 and commissioning of full scale zinc cleaner columns is planned for mid 1991. This paper summarizes the results and describes some of the experiences with column flotation at the Pasminco South Mine.

Jan 1, 1991

By Yongjin S

Datong coal Mine suffers from delays and sudden caving of its massive competent conglomerate roof. Detailed geological studies of the nature of pebbles and matrix of the conglomerate and its sparse bedding, joint and fracture structure, gave rise to investigation of water injection to destroy its strength and to control caving. Comparative investigations, including porisity, permeability, compressive strengths and water injection of conglomerate and sandstone led to empirical expressions relating various properties and to guidance for effective injection and caving practice. This new safe roof control practice should be even more improved with further research, including Modelling.

Jan 1, 1992

Two significant TBM boreability predic- tion models are outlined. Predicted advance rates are compared with actual advance rates taken from twenty case histories. The results show that a simple low cost method that uses one machine parameter and one rock parameter compares very favourably with a high cost sophisticated method which also includes information regarding discontinuities in the rock mass. The effect of rock texture on drillability is also examined. A method of quantifying rock texture has been developed and is outlined. Experimental results show that the developed TEXTURE COEFFICIENT returns highly statisti- cally significant correlations with drilla- bility data in a wide range of rock types.

Jan 1, 1987

By Jeffrey IC

This paper presents a method of measuring field power consumption of shearers and deriving specific energy consumption versus shearer haulage speed performance curves. A description of a computer program which simulates the cutting action of a shearer drum is presented. A comparison between the field specific energy curves and the computer simulation results is made. The simulation results compare well with the field data where all the coal seam is being cut by the shearer. The computer simulation results give back-calculated field pick force cutting characteristics, which allow the performance of the shearer to be predicted for other operating conditions, e.g. effect of changes to pick lacing, effect of changing the drum rotational speed, allows the calculation of power requirements for a particular production rate.

Jan 1, 1992

By Lu S, Jiang Y

The conventional transportation system in open pit, a to u.* itc:,~> truck., to carry the ore along the ramps. Normally, the transportation distance increases greatly as mining progresses deeper. A new approach to overcome the above disadvantage is to adopt a buried roadway by which ores is transported by conveyors from the mining area to the outside dump in the shortest distance so that the production efficiency is greatly increased. Maintenance of the buried roadway in a good working condition is the key factor that determines the success or failure of the proposed approach. This includes the determination of support load, types and structures of support and other related supporting measures. The crucial problem here is to effectively control the load applied on the buried roadway in a certain range that the ordinary support can stand. Based on the theoretical analysis, numerical modelling and physical simulation testing using equivalent material, this paper studies effects on control of the support load by adopting certain measures, for instance reinforcing the surrounding rock and placing the extendable layer between the support and a rock mass. Furthermore, the influence of the dynamic load induced by the movement of heavy vehicles on the stability of the buried roadway is also investigated.

Jan 1, 1995

The Nelson province was chosen as the prime area for rhenium sampling, based on its mineral associations. Sample preparation involved benefication by grinding and flotation A modification of published procedures for rhenium analysis was developed and the results compared with those obtained for molybdenum on the same samples using atomic absorption spectroscopy. The results of the analysis for both metals is discussed and the relationships between rhenium and the molybdenum mineralisa- tion of this region is commented on. A metal- 1ngenic province is defined for molybdenum and r'.ienium and the tectonic setting for this is discussed. Some consideration has been given to rhenium possibilities in Fiordland and the Coromandel Range.

Jan 1, 1980

The advent and easy availability of fast and powerful digital computers has marked a transition from one era to another in the field of process control in many industries. Mineral processing is no exception. Aims, practices and problems associated with process control of mineral beneficiation plants in the 'old days' are compared with those available at present. Although basic processes remain generally the same, there have been simultaneous social and economic developments, which directly relate to the development and present value of process control. Lower head grades are now treated, plant capacities have increased, and a large proportion of future capital in the mineral industry will be associated with large capacity plant, treating still lower grades. Environmental considerations have pressurised moves to better control in some areas. With these changes, economic operating incentives have changed, and process control has, in many plants, become more critical. Finally, while computer technology has developed recently at a very rapid rate, developments in the fields of instrumentation, basic on-line measurement and sampling have in general lagged behind, limiting the progress possible in process control. Hence, the benefits of computer control vary depending on

Jan 1, 1977

By Yesil MM, Bozdag T

The swelling process is an impor- tant problem causing damages to the structures in or on swelling rocks, both during construction and operating life. To understand swelling problem, a number of testing methods have been developed by many researchers. In these studies, the swelling parameters, in most cases, are derived from oedometer tests. The swelling parameters determined from oedometer type tests represent one-dimensional behaviour (one-dimensional swelling law) therefore, it is quite difficult to extrapolate the oedometer type test results to the three-dimensional in-situ conditions. To overcome these problems, a three-dimensional approach is suggested for clay bearing rocks. Results of triaxial swelling tests conducted on marl from Dodurga Lignite Coal Mine are presented. Triaxial swelling characteristics of the marl are presented and design approach for tunnels is described.

Jan 1, 1992

By Vassiliev P

Cut-off optimisation, based on the work of Lane (1988), can be used to maximise the NPV (Net Present Value) of a mine by the judicious manipulation of cut-offs and the use of stockpiles. Apart from maximising NPV, cut-off optimisation will ver

Jan 1, 1998

By Ramani R. V

There are many important physical phenomena in mine ventilation which involve transient mass and heat transfer processes. These processes have been modeled using differential equations often solved with close form solution. Within the last two decades, many numerical schemes have been devised to solve these mass-transfer problems. Much of this effort has focused on variants of the finite element and finite difference methods. In this paper, the solution of mass transfer models in mine ventilation by finite difference technique is discussed. Specifically, the computational effort and the accuracy of the solution are presented.

Jan 1, 1988

By Sparrow G. J

In a recently completed AMIRA project, 20 samples were searched for gold mineralisation using the automated location facility (ALF) for rare phases on a scanning electron microscope in the CSIRO Division of Mineral Products, Melbourne. The samples were submitted by mining companies in Australia, and Papua New Guinea, and included crushed ore samples, cyclone overflow and underflow products, a flotation concentrate, and 12 tailing samples. Their gold contents ranged from 600 to 0.2 g/t An. Native gold and gold minerals including a gold telluride, gold-silver tellurides, and a gold bismuth mineral, were located in the samples as free grains and associated with other minerals such as pyrite, magnetite, hematite, ankerite, copper sulphides, silicate minerals, and quartz. In the highest grade samples, both micron sized and 200 ¦m grains of gold were found with ALF. It would be difficult to locate such d wide size range of gold in a manual search. Gold mineralisation was located in the tailing samples assaying 0.4 g/t An and higher. In several tailing samples coarse grains of native gold over 40 p.m in size were located. One grain was estimated to have contributed 40 per cent of the gold in the sample. As well as locating gold mineralisation, the ALF examination resulted in the identification of uranium, mercury, and bismuth minerals in the samples. Knowledge of the distribution of these minerals in processing streams could be important in the operation of a concentrator.

Jan 1, 1992

By R K. W Merkle, E Whiteman

The anorthosite complexes and related rock types of the Indian Precambrian shield are primarily associated with either cratons or mobile belts. They were metamorphosed under amphibolite to granulite facies conditions. The major rock types are chromite-bearing meta-anorthosites, amphibolites, basic granulites, pink granites and gneisses. This study was carried out on chromitite bearing samples from Sittampundi Anorthosite Complex (SAC), Tamil Nadu, to evaluate the nature and textural settings of platinum-group minerals (PGM), using state-of-the-art technology. The structure and petrology of SAC were well studied by earlier workers (Subramanian, 1956), but only scanty data on geochemical, petrology and mineralogy of PGM are available. The mineralogy of the samples is dominated by chromite (>70 mass per cent), plagioclase (An90) and chlorite-actinolite with orthopyroxene (En85). Details of the petrological evolution of the Sittampundi complex will still have to be studied further, but indications of magma replenishment at the level of chromite formation and the elevated PGE values associated with the chromitite samples make the Sittampundi complex a promising target for future exploration activity.

Jan 1, 2008

By Bailey S, Avraamides J, Jayasekera S

The anodic dissolution of iron from three different Western Australian reduced ilmenites was investigated using the carbon paste electrode technique. A characteristic current-potential diagram, called a cyclic voltammogram (CV), was obtained for each of the reduced ilmenites. The shape of the CV measured for all three reduced ilmenites was strongly time dependent. The effect of electrolyte composition and temperature on the CV of one reduced ilmenite was also investigated. The results suggest that the initial surface of iron in reduced ilmenite is slow to dissolve and that chloride ions and higher temperatures accelerate the dissolution of this initial surface layer. However, after removal of this layer, the dissolution rate was essentially independent of the electrolyte composition and the temperature.

Jan 1, 1996

By Binns RA, Murao S

The PACMANUS and Jade deposits are two active hydrothermal fields that are forming massive sulfide deposits at the Pacific rim margin. Both are associated with felsic submarine volcanic rocks and both occur in back-arc settings. However, PACMANUS is associated with almost sediment-free dacites and lies on the crest of a volcanic ridge, whereas Jade occurs in a heavily-sedimented tectonic depression associated with a basement of pumiceous rhyolite. The PACMANUS deposit is richer in Cu and Au, and Jade in Pb. Zinc, Ag, As and Sb contents are similar. Sulfide textures at PACMANUS suggest formation of Cu and Zn sulfides by simultaneous double-diffusion involving inwards-moving seawater mixing with outwards-moving hydrothermal fluid. By contrast, at Jade there is a more complex history of formation where initial growth of barite on the sediment surface, probably associated with microbial activity, formed an impervious cap which trapped higher temperature hydrothermal solutions.

Jan 1, 1995

The Knelson Concentrator is a centrifugal gold concentrator developed in Canada, which utilises the combination of high gravitational ("G") forces and a unique fluidising action to efficiently recover free gold particles from minus 6 mm to fine micron gold in both alluvial and hardrock applications.Operating parameters including water requirements, fluidising pressures and feed rates are given, as well as an indication of their various effects on gold recovery.Results include a Colorado School of Mines Research Institute (CSMRI) report comparing the Knelson concentrator with various other gravity concentrators.

Jan 1, 1984

By Kavetsy A

In surface mining operations, the ease with which a muckpile may be dug is a dominant factor in mining efficiency. Within broad limits this is largely independent of the fragment size dis- tribution, since the equipment used to move the broken rock is generally larger than in underground mines. In such cases, muck- pile shape and voids ratio within a muckpile heavily influence mine productivity. In a particular operation, the muckpile shape after blasting should be tailored to the digging equipment being used. A front- end loader is best suited to a low, flat-lying, loose muckpile, because of its fairly good mobility and small break-out force with its bucket. In contrast, a rope shovel lacks mobility, generates a much larger break-out force with its bucket, and fills its bucket in a vertical filling motion. Therefore, it is ideally suited to well fragmented, steep faces. In situations where a dragline is used, the requirement for a suitable muckpile depends on the operat- ing scheme of the dragline. For a conventional highwall key method the preferred work- ing level of the dragline is the same as the highwall, so that the dragline may sit over its key. In this situation, the ideal muck- pile shape involves relatively little displacement of the fragmented rock, with a minimal "power trough" at the back of the blast. In throw blasting, on the other hand, it is desirable to cast as much of the spoil as possible across the pit. It is then necessary to optimize the blast design by maximizing the throw percentage under any necessary constraints (e.g. damage, vibration, flyrock, explosive cost).

Jan 1, 1988

By Gray N. B, Floyd J. M

To gain further understanding of the operating efficiency of the BHP Slab and Plate Products Division (SPPD) RH vacuum degasser, physical and mathematical model studies of the process have been undertaken. The purpose was to investigate how the various process parameters affect the liquid circulation rate, to visualise the flow patterns, and to identify and eliminate the cause of localised wear in the downleg. In the physical model mixing times were measured using an acid tracer technique. The results were applied to predicting trends in times required to obtain homogenous melt composition under varying conditions. A 2-dimensional mathematical model describing the liquid metal flow has been developed using the PHOENICS fluid-flow package. The physical model results were simulated and incorporated into the mathematical treatment and an improved design for vessel geometry is proposed. The effect of rounding the downleg entrance or installing a baffle between the legs is discussed.

Jan 1, 1987

By Dunlop A. C

A brief study from the Mt. Bulga prospect com- pares the chemistry and mineralogy of different soil fractions and other materials to suggest a sequence of surficial metal dispersion from adjacent gossans, which may have relevance for geochemical exploration in semi-arid terrains. v v v v v JIV-- v v v v a o v o/ v v v v 1 v v lv ./v '' 1 v 16400N ..I v 1635014 v 1630014 .:1 ò.t SILURIAN sillstone " lelsic volcanic sillstone -sandstone ORDOVICIAN Eandesite o quartz float gossanò pits doOP Iv o shalt v _--'fault v 1---1 soil traverse v v v v 0 100 200 mm e Fig. I Local geology and location of soil traverses, Mt. Bulga (compiled from Chisholm, 1976). The Mt. Bulga prospect in central New South Wales is a small but well documented volcano- genic massive sulphide occurrence (450,000t of 0.8% Cu, 1.3% Pb, 5% Zn and 0.45 g/t Au) Cambrell and Kirk (1974), and Chisholm, (1976). Mineralization is localised near the interface of felsic pyroclastics with overlying silt- stones and along adjacent faults (Fig. 1). In this area with a Koeppen type cf6 climate, soils are thin and skeletal along ridges with thicker and better differentiated profiles with a colluvial component up to 2m thick developed

Jan 1, 1988