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The problem of manufacturing from sulphuric 'acid and Christmas Igland "A" phosphate, superphosphate of acceptable physical condition and agronomic phosphate availability, is directly related- to the crystallisation of a reac- tion product, monocalcium phosphate monohydrate. Two solutions to the problem, vacuum drying the superphosphate and calcination of the ore before reaction with acid, are discussed.

Jan 1, 1971

By Roberts M. L

Long Shaft was initially developed using a rail haulage system on every working level comprising battery electric locomotives and granby trucks loaded by rail mounted rocker shovels. Production was commenced using conventional hand held cut and fill mining methods. In an effort to improve productivity and reduce operating costs a mechanised cut and fill stoping method evolved to suit the wider sections of the orebody. To further improve productivity and reduce costs the mechanised levels of the mine are progressively being redeveloped to enable the use of trackless diesel haulage equipment. An added benefit of trackless haulage equipment will be the ability to place development mullock into stopes as Fill.

Jan 1, 1988

By R L. Verburg, R Johnstone

DeBeers Canada Mining Inc (DeBeers) recently submitted an Environmental Assessment (EA) for its proposed Snap Lake Diamond Mine located in Northwest Territories, Canada. As part of the EA process, a site water quality management plan must be developed. Plan development requires an integrated approach such that the key factors influencing water quality can be identified and managed to minimise potential impact. A system model was therefore developed to simulate the site-wide water quality conditions and mass loadings to the principal environmental receptor of concern, Snap Lake, during operations and post-closure. Requirements of the simulation included integrating hydrology, geochemistry, hydrogeology and site management practices in a dynamic way. A unique feature of the site was the need to accommodate a complex flow system that included a feedback loop between lake water and mine water. A system model was constructed using the GoldSim software package that integrated on-site water quality and flow measurements, as well as results from independent groundwater flow and geochemical modelling efforts. The GoldSim model simulated concurrently the movement of 39 solutes through the subsurface mine and surface facilities. Solute sources considered included four different waste rock and tailings types, explosives use in the mine, treatment plant discharge, and recycled process water for dust suppression. Separate solubility constraints were identified for different regions of the flow system (eg underground mine; treatment facility; surface water bodies). Kinetic test data were used to derive temperature-dependent rate constants for use in calculating mass inputs from surface sources such as waste rock piles. The model generated water quality estimates over time for a variety of management scenarios at several potential discharge locations. The integrated approach used by the model was effective in identifying the significance of key factors influencing overall water quality such as explosives use, mine water inflow rates, waste rock reaction rates, site/mine management options, and effectiveness of treatment. The model provides an example of an effective tool for comprehensive, integrated system evaluation and management.

Jan 1, 2003

By Denby B, Miles N. J

The underlying theory behind the construction of an on-line size analysis system is described together with an introduction to the Artificial Intelligent techniques that it is founded on. Previous systems based on more traditional technology such as edge detection and dilation algorithms have been restricted by the significant processing power they require, this has resulted in the production of systems with either reduced functionality or severe hardware requirements. A neural network approach offered a new perspective to the problem of size analysis; the ability of a network to learn and recognise subtle patterns in training data before on-line processing is initiated opened up the possibility for the production of a fully functioning practical system. The format of the training data had to be carefully analysed prior to its implementation in a neural network as the capability of a neural network solution depends as much upon a suitable data preparation as it does on the system architecture. To facilitate experimentation with various profile quantification techniques such as fourier and fractal analysis an Image Profile Analysis System was constructed (IPAS) in software on a personal computer. The IPAS system was produced with the aim of pre-processing image data to create data sets for experimenting with external neural network packages. The system allows the analysis of both real images obtained by image capture and simulated images created by an in-built in simulator. A measurement comparison scheme is also included together with a case study concerned with the frequency analysis of simulated images. The power of neural networks combined with the data compression provided by profiling removes the need for direct measurement of individual particles. This has obvious implications on the level of hardware necessary, and ultimately the expense of a stand alone system. The extrusive nature of data collection via an image analysis system will also permit simple installation of a shipped system; eliminating any requirement for interference with existing machinery.

Jan 1, 1995

By Bruce P, Luyendyk

The South Island of New Zealand comprises a collage of distinct tectonostratigraphic terranes. Some tectonic models predict that these terranes formed on or near the margin of Gondwanaland. However, geologic evidence suggests that some of these terranes may be exotic. Over 400 samples from 30 sites were collected from the Brookstreet terrane within the Takitimu Mountains. The section includes the early Permian Takitimu Group and the late Permian White Hill Intrusive Suite. Over 80% of the rocks show a partial or complete regnetization in the present field due to recent acquistion of VRM. Although some remagnetization of the Takitimu Group occurred during the emplacement of the White Hill Intrusives, both early and late Permian direction have been isolated. These directions indicate a mid-latitude origin for the Brookstreet terrane, and suggest a strong clockwise rotation between early and late Permian time. A published paleomagnetic result from the younger, but related, Murihiku terrane suggests that the Brookstreet terrane was sutured to the margin of Gondwanaland by the late Triassic, or that the Brookstreet and Murihiku are two distinct terranes.

Jan 1, 1987

Christmas Island "C"-grade phosphate consists essentially of the minerals crandallite and millisite. Although containing over 25% P205, this material is not suitable for the manufacture of water-soluble phosphate fertilizers by conventional processes, because of its high iron and aluminium content Cover 25% total R203). In order to produce a water-soluble fertilizer from such material it is necessary to separate the iron and aluminium from the phosphate, which must report in a product acceptable as a fertilizer. Several processes were studied in detail. The first used ion exchange for dissolution and separation and yielded diammonium phosphate; processing costs were high compared with conven- tional processes based on apatite. The latter processes have basically simple flowsheets and cost of processing is low when compared with the costs of the raw materials. The need to separate iron and aluminium from the phosphate introduces additional complexity into the treatment of the C-grade material. The higher processing costs might be justified, however, if alumina could be produced as a byproduct. Two proposed processes have been developed in which: 1. hydrochloric acid is used for dissolution, and solvent extrac- tion for the separation of ferric chloride from phosphoric acid. Aluminium chloride is precipitated and hydrolysed to recover alumina and hydrochloric acid. 2. sulphuric acid is used for dissolution and aluminium is crystallized as ammonium alum. The phosphate is produced as an ammonium phosphate-sulphate fertilizer. High purity alumina can be obtained by treatment of the recrystallized alum. The technology of these processes is described, and their broad economics discussed briefly.\

Jan 1, 1971

By Neville WE, Parkinson J

One of the earliest recorded risk management schemes was implemented by the boatmen of the Yangtze river some 4,000 years ago.. Between them they arranged for shipments to be split up in such a way that a load was divided five ways: if one was lost, then 80% of the shipment got through. Bottomry contracts were in vogue in Babylonian times with similar systems being used in India, in 60OBC and 4th century Greece. One of the first accepted mutual insurance ideas came in 1835 when a mill owner in America negotiated a lower insurance premium in return for installed fire safety measures. Approximately 20 years ago risk management as a philosophy was developed in the U.S.A., the philosophy followed to England and hence to Australia about 10 years ago. The business climate which induced the philosophy of risk management was that of "tight money". The definition of "assets" was then broadened to include earning capacity, skilled personnel and in a negative sense, a corporation's liabilities. In more affluent days losses were comfortably absorbed into the ongoing business expenses, the more prudent managers took out insurance which "covered everything" at a suitable premium. Statistics are available to indicate that a high percentage, (over 60%) of businesses which suffer massive plant damage due to fire, do not restart operations, or in the event of restarting have closed operations within the next 2 to 3 years - in spite of collecting an insurance payout.

Jan 1, 1986

By Gente P, Eissen JP, Lafoy Y, Charlou JL

The North Fiji Basin (NFB) is delineated by the Vitiaz trench to the North (paleo sub duction zone, Brocher, 1985), the Vanuatu is- land arc (called before New Hebrides arc) to the West and South, the Hunter Fiacture Zone to the South-East and the Fiji islands to the East (Brocher, 1985 ; Larue et al., 1982 ; Carney and MacFarlane, 1982 ; Falvey, 1978). The NFB is characterized by shallow water depths (about 3 km) (Chase et al., 1982 ; Scla- ter et al., 1972 ; Karig, 1971), high heat flow (average of 2.29 HFC) (MacDonald et al., 1973 ; Halunen, 1979), strong positive free air anoma- lies (Worzel, 1965 ; Kogan, 1976 ; Luyendick et al., 1974 ; Solomon and Biehler, 1969) and a geoid anomaly (Malahoff and Larue, 1979) inter- preted as a geoid swelling. Few refraction data reveal a relatively thin crust and sediment co- ver, and the existence of low speeds in the up- per mantle beneath the NFB (between 7,1 and 7,7 km/s) (Larue et al., 1982 ; Raitt, 1956), which could indicate the existence of active spreading zone(s) in this area (Barazangi et al., 1974). Global seismicity of the SW Pacific clearly de- fines the.limits of the NFB, as well as the Lau basin (Sykes et al., 1969). But one can note the low level of shallow seismicity of the NFB (Ham- burger and Isacks, in press) which concentrates in three distinct trends :

Jan 1, 1987

By T Muri

The drying operation of materials from particulate solids, through slurries and suspensions, to continuous sheets represents an important part of several processes in the chemical and mineral industries. The increasing demand of high productivity at low cost and minimal environmental impact makes it complex to evaluate and choose the best available drying technology for each industrial application. The drying technologies are mainly characterised on the basis of how the wet product is related to the drying medium, namely: direct and indirect drying. In the direct drying method (convection drying), the product is brought into direct contact with the drying medium, which may be hot gas or air. Large quantities of gas are necessary for transfer of the required energy. A special case of the direct dryer is the fluid bed dryer, in which the product floats on a cushion of air or gas. The process air is supplied to the bed through a perforated distributor plate and flows through the bed of solids at a velocity sufficient to support the weight of particles. Very high heat and mass transfer values are obtained as a result of the intimate contact with the solids and the relative velocities between individual particles and the fluidising gas. In the indirect drying method (conduction or contact drying), the wet product is separated from the drying medium. The drying unit can consist of a rotor forming the indirect contact heating surface mounted in a stationary or rotating shell. The indirect method uses saturated or superheated steam resulting in low energy consumption and minimal environmental impact. In this paper, a review is given of the technologies available on the market based on different drying methods. The advantages and the disadvantages are summarised with respect to issues such as investment and operating cost, maintenance, product capacity, product handling and environmental impact.

Jan 1, 2006

Recent operating experience from West Australian open pit gold mines has shown that geotechnical input into initial design is rare. As a result, ground stability is poor - almost half the pits designed in this way suffer major failure.West Australian experience shows that geotechnical studies for individual mines are site specific, and therefore empirical experience cannot be transported from site to site. Geotechnical studies performed prior to design have resulted in significantly improved pit stability.

Jan 1, 1990

Many of the large refrigeration plants used in, the cooling systems on deep South African gold mines are situated on surface where they are exposed to seasonally and diurnally varying climatic conditions, and to a diurnally varying demand for cooling made by the mine. It has been traditional to accommodate the seasonal variation in climate by manual control applied to the plants at appropriate times of the year, and the plants have normally been specified to conform passively to the diurnal variations. This paper introduces new strategies for the active automatic control of the plants on a diurnal cycle, and shows that attractive benefits in energy and chilled water resource management can be accrued through the use of these strategies. The results have been derived through the modelling and simulation of a representative refrigeration plant.

Jan 1, 1985

The production of synthetic crude oil requires a suitable coal or a coal extract modified by hydrogenation for pyrolysis. Existing classifications are broadly based on historical and current needs. One, Seyler's, is based on a visual display which can be used to present petrographic bounds. The analysis of the coal extracts from solvent hydrogen-donor testing allows an experimental limit to be described and a plant limit to be indicated. Australian black coals are discussed within these petrographic and plant bounds and their limitations as a feed for the production of synthetic crude presented. Potential uses for the aromatic liquid products are suggested. The application of the diagram as a screening procedure for sub-hydrous coals is described.

Jan 1, 1975

By D A. Kepert, D Clark

During early 2004, Fortescue Metals Group (FMG) began an aggressive exploration and drilling program in the Chichester Range, targeting iron enrichment developed in the Nammuldi Member at the base of the Marra Mamba Iron Formation. The timely recognition by FMG of distinct zones of (hypogene) microplaty hematite (mplH) enrichment overprinted by extensive supergene mineralisation led to an early reappraisal of the geological history of the area and characterisation of the possible structural and stratigraphic controls on mineralisation. Regionally, the Chichester Range dips gently at less than 5¦ to the south, however, detailed mapping shows that this regional limb is overprinted by low amplitude, long wavelength, north/south to northeast/southwest trending folds. The locations of major structures in the Marra Mamba Iron Formation, combined with spectral analysis of known mineralisation, allowed extrapolation and prioritisation of exploration target areas. The delineation under cover and understanding of these structures was enhanced by detailed airborne magnetic data. Recognition that supergene mineralisation was associated with a palaeotopography that continued significantly under cover to the south under sediments of the Fortescue River valley led to the discovery of extensive supergene mineralisation together with additional mplH mineralisation. A model for the landscape evolution and preservation of enriched Nammuldi Member was generated in order to help communicate both the complexities involved with targeting drill holes beneath cover and the potential limits to the lateral extents of mineralisation.

Jan 1, 2005

The first continuous pressure disk filter took up industrial-scale operation in Germany in 1976. This paper comments on major components of pressure filter facilities from the point of view of industrial-plant suppliers. For lack of time aspects of economy have not been commented upon. The paper elucidates a number of process-engineering inter-relations. It outlines important development trends from the angle of a machine-building company.

Jan 1, 1989

This paper reviews the geochemistry of weathered nickeliferous sulphidic and lateritic profiles, the supergene behaviour of nickel and ore-associated elements, and their implications for exploration in an attempt to distinguish between barren and mineralised nickeliferous profiles. Nickel is an abundant accessory element in ultramafic rocks with background concentrations in some units up to 0.25 weight per cent. Ore-grades in fresh rock are mostly associated with massive and disseminated sulphide zones within magnesium-rich layered ultramafic sequences. In lateritic weathered terrain, nickel is also concentrated in the regolith profile. This process not only upgrades nickel in the gossanous weathered product of sulphidic deposits, but for sub-economic sulphide zones and some ultramafic rocks, is sufficient to result in a supergene resource. Ore-grade accumulations of nickel in regolith after sulphide-poor ultramafic rocks are referred to as lateritic deposits. Nickel sulphide zones and their ferruginous weathering products are collectively referred to as sulphidic deposits and are the major source of nickel in Western Australia. Mineral exploration in the Yilgam Block is hampered by deep lateritic weathered profiles (eg Butt and Sheppy, 1975; Smith, 1977; 1982). During the nickel boom of 1967 - 1972, most discoveries resulted from the location of outcropping nickeliferous gossan and ironstone. Exposed ultramafic terrain with nickel sulphide potential were explored intensively, mostly by gossan and soil sampling. However, up to 85 per cent of the area of the Yilgarn Block is buried by transported regolith. In these covered areas, barren and mineralised rock responses at the surface are similar and soil sampling produced unreliable results due to many false anomalies. A statistical, multi-element approach to regional geochemical exploration has evolved. Potential trace element indicators investigated, include Co, Cr, Cu, Ir, Mn, Pb, Pd, Pt, Sc, Se, and Zn. In recent years, trace element ratios have also been tested with varying degrees of Success.

Jan 1, 1996

This paper presents a new idea in field data collection for geological and scientific data. The computer keyboard has been replaced by a barcode wand driving a spreadsheet style editor. To use the full capabilities of computer hardware currently available, geotechnical and geological data can be entered and validated in the field, in a structured format, for later transfer into modem geological modelling databases. An example, using a geotechnical borehole log, explains the principles discussed. The generic nature of the Datcol system is illustrated by the application developed using the Norwegian Geotechnical Institute Rock Mass Classification system. A brief description of a modem spatial relational database is also given with particular reference to underground engineering.

Jan 1, 1993

By Yokozawa K, Yamamoto T, Kameoka Y

Japan Construction Method and Machinery Research Institute has been conducting various field surveys of tunnel works and other excavation works, and the cost and efficiency of these two excavation methods have been studied. Based on these data, the costs of blasting excavation and mechanical excavation represented by roadheaders were calculated. The costs were calculated and compared for rocks of various hardness. When the total construction cost is considered, the degree of overbreak becomes one of the most influencial factors, because the overbreak area must be filled up with expensive shotcrete in NATM. So, in the next step, the relation between the excavation costs considering overbreak and the rock hardness was studied using the data on overbreak obtained by the field survey.

Jan 1, 1987

The geology of an area in north-western New South Wales, bounded by the South Australian and Queensland borders, latitude 32° S. and longitude 14° E. is discussed.The area involved includes sixteen 1:250,000 standard military sheets and covers approximately 96,000 sq. miles.The geology of the Willyama Complex is not dealt with but a small area of metasediments previously included in this unit is separated and a possible correlation with Precambrian to the east is suggested. Torrowangee Group sediments are described and the problem of nomenclature using a glacial implication is raised.Nine areas of proven Lower Palaeozoic sediments are considered and their relationship to the boundaries of the Bancannia Trough outlined. It is possible that some exposures not yet substantiated by fossil evidence may prove to be Lower Palaeozoic rather than Precambrian in age.The sediments of the Lachlan Geosyncline in the area of the Cobar massif are described and new concepts on the age and distribution of some of the established stratigraphic units are introduced. The absence of rocks of Middle Silurian age probably indicates the time of a major orogeny in this area.Lithology, thickness, and distribution of the Upper Devonian sediments is considered and some of the more recently found fish plate localities are listed.Mesozoic sediments occur in isolated areas of Lower Jurassic age and in the Great Australian (Artesian) Basin. A four-fold subdivision of sediments of the basin has been possible in some areas but lack of sub-surface information at present, precludes the possibility of correlation with the type sections in Queensland.Units in the Cainozoic are subdivided and a five fold subdivision of the Quaternary, at present being used throughout western New South Wales, is described.

Jan 1, 1969

By Botz R. W

Macroscopic and microscopic studies of the outburst-prone Gemini Coal (Bowen Basin) showed that outbursts were associated with a localized inertinite-rich ply. Previous studies of the Gemini Coal had shown a general relationship between desorption rate, regarded as a good measure of outburst proneness, and inertinite content of coal samples.Desorption rates increased with increasing inertinite content and were highest for inertodetrinite-rich samples. These results suggest that inertinite content and composition play a significant role in outbursting and may be useful in identifying outburst-prone coals, which could be confirmed by desorption measurements.Consequently outburst-prone areas in the Upper Permian coal measures ofthe Sydney, Gunnedah and Bowen Basins have been defined using a combination ofthe parameters, inertinite content, depth ofcover and coal rank. In the Upper Permian, inertinite-rich coals are confined mainly to the top of the coal measures, except in the Sydney and Gunnedah Basins where an inertinite-rich interval (Bayswater Coal and correlatives) is also present towards the base of these measures. Only a small area ofthe central Sydney Basin, butmuch ofthe north-eastern and north-central part of the exposed Bowen Basin is considered outburst prone on the basis of these parameters.The most outburst-prone inertodetrinite-rich lithologies have a patchy and unpredictable distribution in the top of the Upper Permian coal measures. They can be defined only by sampling and petrographic analysis at the subsection level.

Jan 1, 1986

By Valery W, Morrell S, Loughlin P, O&apos

Traditionally, blasts in mining operations are designed to prepare the in situ rock mass for excavation and transport without much consideration being given to the downstream comminution processes. Blasting is in fact the first step in a chain

Jan 1, 1998