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The exploration and mining risks are investigated and compared to the risks of smelting, secondary processing and other normal industrial activities. This study concentrates on the risk before, or at the investment decision. Internal and external risks are distinguished. Internal risks are the risks inherent in every engineering design and common to all projects. The main external risks are the financial risk, changes in prices, location problems and geological factors. Financial risks concern every capital-intensive and export-oriented project and cannot be considered as typical mining risks. Changes in prices, i.e. the market risk, concern every industry using raw materials, but the market risk is especially accentuated in the mining industry. Problems of location and infrastructure are normally more significant in mining than in other projects, and geological risks are unique to mining. All these risks associated with mining projects combine to form a risk at least twice as high as that for other normal industrial activities. Within the range of profitability of mines, which on average is the same as in the manufacturing industry, only a few highly profitable mines exist. These few mines are the sole reward for the high risks taken.

Jan 1, 1986

The physical phenomena which influence gas flow in the bosh and hearth of a blast furnace are discussed including the hold-up of slag as a mechanism which can result in a flooding condition. An equation is defined which describes the limitation to wind volume arising from the flooding condition. Implications of the various factors influencing bosh and hearth gas flow on furnace operation are discussed. Coke quality is shown to be the most important factor in the aerodynamics of these zones and coke requirements are defined for the Port Kembla No. 5 BF which has an inner volume of 2670 m3.

Jan 1, 1975

By S Pigram, G J. Jameson

This paper is concerned with the tracking of particles in the froth phase of an aerated water/glycerol mixture. Experiments have been carried out in a specially designed laboratory flotation cell that allows formation of a deep froth. Phosphorescent tracer particles of various sizes were injected into the centre of a froth column where they were excited by ultraviolet lights, positioned at the back and front of the column. The motion of particles was captured on a digital camera with a green filter. The images from the digital camera were then transferred to a computer and an image analysis program was used to convert the colour intensity to the concentration of particles at each location within the froth. The tracer technique was used to determine the dispersion of hydrophilic particles and the variation of the concentration of solids with axial and radial positions.

Jan 1, 2005

The MIMDAS geophysical data acquisition system developed and tested by the former MIM Exploration Pty Ltd (MIMEX) is now commercially available worldwide through Geophysical Resources and Services Pty Ltd (GRS). The system implements several new features in its design that give it significant advantages over conventional systems and allows for new approaches to electrical exploration. In particular, the achievable signal to noise levels permit exploration to depths once thought beyond the range of electrical exploration. The flexible multi-channel configuration lends itself to truly 3D surveys in the style of modern seismic techniques. Each of these aspects is illustrated with a number of case histories from both Australia and South America.

Jan 1, 2004

By Bogar D. V

Often dewatering of coal tailings is inhibited by the presence of clays, making it difficult to obtain a high concentration, handleable coal tailings. The net result can be a low concentration, chocolate mousse-like tailings which poses significant sedimentation problems in a tailings dam and represents a significant environmental problem. This paper examines the coal tailings from a Hunter Valley colliery where the tailings properties are influenced significantly by the presence of montmorillonite clay. The influence of the calcium ion on the rheology and sedimentation/compression behaviour of coal tailings . containing montmorillonite already dispersed in water was investigated and revealed that very little improvement in the properties is achieved through the coagulation. The preliminary investigations also indicated that the properties of the tailings were dominated by the presence of the montmorillonite clay. Thus investigations were carried out on the clay alone in water. Investigations into the effect of dispersing samples of the clay alone in water and then coagulating with calcium compared with dispersing the clay directly into calcium ion solutions at the same calcium concentration showed huge improvements in the rheology, compressibility, sedimentation rates and sediment solids concentrations for the second dispersion method, which can be called controlled dispersion. The sediment volume fraction solids improved by more than a factor of two by controlling the dispersion of the clay. The reason for the improved properties lies in the suppression of the initial swelling of the clay, which is initially in the sodium form, thus maintaining the parallel orientation of the platelets that is present before wetting. While swelling is being suppressed, ion exchange occurs with the calcium which results in permanent swelling suppression. In the uncontrolled dispersion case where swelling is uninhibited, the clay is allowed to break up and despite the powerful coagulating nature of the calcium ion, the random orientation of the high aspect ratio clay platelets inhibits effective coagulation. Results indicate that the initial electrolyte concentration of the washwater in a coal washery is the critical factor controlling the dewaterability of clay tailings and the handleability of the dewatered product rather than the actual act of coagulating with the calcium ion. The results presented are of clear practical significance and indicate how coal tailings problems where clay dominates the rheology can be improved considerably by knowledge of the surface chemistry.

Jan 1, 1995

By C Kocsis, G Baiden, Y Bissiri

CANMET-MMSL and Penguin Automation Systems Inc have been exploring how process simulation and ventilation modelling software, when combined, can be used to optimise hard-rock/metal mine ventilation systems. In combination, it is anticipated that this methodology will facilitate the exploration of mine design options that affect ventilation requirements and ultimately cost. Such integrated mine design could limit, and possibly reverse, the drivers that under current practices would generally dictate increased ventilation, power consumption, cost and greenhouse gas emissions. It is believed that the mining industry needs such process models to develop better business cases. For example, the implementation of optimised ventilation systems will undoubtedly require significant investment and mines are often reluctant to try such conservational measures unless they can be proven cost-effective. In general, Canadian hard-rock mines know their ventilation systems are providing too much air and consuming power unnecessarily. This is because their systems are designed to provide maximum production flexibility, based upon peak demand, which may be at some future time, and operated continuously at that level regardless of actual need. Simplistic analyses have shown electrical energy savings can range from 30 per cent through to 90 per cent (Hardcastle, Gangal and Leung, 1998). These savings depend upon such factors as the intensity and continuity of the production schedule as opposed to non-productive time. Where these savings occur is also important, if limited to either the primary or auxiliary ventilation systems, they could be negligible in a mineÆs total energy consumption. The problem these mines face is determining what level of ventilation is required in real-time and then the relative benefits. Such parameters as varying electricity costs, heating fuel options, different design criteria and their complex inter-relationship can effect the selection of an optimal system, depending on whether energy, environment or cost is the prime driver. The use of process simulators in underground mining is in its infancy; to date they have been used to show the benefits over the life of a mine under different mining methods, such as a comparison of tele-remote mining from surface against conventional manned operation (Baiden, 2000). This ongoing development advances the use of such simulators into a new and potentially important area, namely modelling the life-cycle ventilation requirements of a mine. This paper shows how such a life-cycle analysis as opposed to peak demand can provide the basis for optimising the design of ventilation systems and their control.

Jan 1, 2005

By I F. Wood

Planning for flooding and assessment of flood impacts are important requirements for mining projects, as they are also for other types of development. With more intense development and concern from the community, supported by government regulatory requirements, assessment of flood concerns and impacts has become of increasing importance. To ensure that flooding issues are fully understood and results presented in an appropriate format, advanced hydraulic analysis procedures have been developed and are beginning to be applied. These procedures must be rigorous in an engineering context but the results must also be readily understood by the community and government agencies. Advanced two-dimensional hydraulic modelling is becoming accepted as an important means of assessing flooding issues for mining projects. With presentation of results from hydraulic models with Geographic Information Systems (GIS), flood impacts can be analysed rigorously and presented clearly. This paper discusses the application of advanced hydraulic modelling in the planning and impact assessment of a major mining project located on a floodplain where there is extensive inundation. The analysis provides for both input to the planning of the project and for detailed assessment of potential impacts. This case study illustrates some important aspects of the application of hydraulic modelling using a two-dimensional modelling to a critical flood design.

Jan 1, 2003

A simulation model of the load and haul process where the loader cycle has been subdivided into its individual components is used to consider the benefits derived from improved drill and blast methods. Field data from a Hunter Valley mine is u

Jan 1, 1998

A case study of a landslide, which threatened vital infrastructure essential for the continuous operation of the Ok Tedi copper mine is presented. The paper presents a detailed description of the land- slide, outlines the assets at risk, and how the issue was addressed. This included the consideration of remedial options and the im- plementation of the most economically sound and geotechnically feasible remedial design which was completed within budget and on schedule. The paper is intended to highlight the responsibility of a mine based Geotechnical Engineering section in providing essential geotechnical investigations, design and professional advice on addressing stability issues in the infrastructure region.

Jan 1, 1997

Evidence abounds for sea-level change having occurred throughout geological and recent time. Driven by climatic changes, by cycles of glaciation and deglaciations, and by tectonics the position of sea-level relative to the crust has been going up and down since oceans first formed. Rates of these differential movements have been as high as 10 mm/year during the last major deglaciation as sea-level rose by about 150 m in about 15000 years. Tectonic processes can also produce change in sea-level relative to the crust of several mm/year as in, for example, the uplift of the Huon Peninsula in Papua New Guinea. To understand what is happening to sea-level today and what may be happening in the future it is necessary to understand the geological and climatic processes that have caused sea-level to change in the past and the best laboratory for the study of these processes is the geological and geomorphological record. Evidence for observations of sea-level change throughout Late Pleistocene and Holocene time is plentiful in the Australian region. Temporal variability is characterized by a low-stand, at more than 100 m below the present level, at about 20 000-18 000 years ago followed by a rapid rise and transgression of the continental margin up to about 6000 years ago. After this time sea-levels remained within a few metres of their present value but the patterns of change are not everywhere the same. The depth of the low stand at about 18 000 years ago does not appear to have been the same everywhere. Nor does the time at which sea-level first reached its present value appear to have been everywhere the same. The fluctuations about present sea-level during the past 6000 years appear to have been different in different localities. As yet there has not been a wholly satisfactory quantitative explanation for this spatial variability. How much, if any, is indicative of vertical tectonics? How much is the result of the Earth's response to the changing surface loads as mass is exchanged between ice sheets and the oceans? Can any of it be attributed to past changes in global climate? Or are the observations just wrong?

Jan 1, 1990

By A G. Dempster, N Barnett, J Oh, S Saydam

NASA’s Artemis III mission is expected to return astronauts to the surface to explore and sample the lunar volatiles by 2026. These volatiles are anticipated to provide scientific insights as to how the Moon was created and economic value to off-Earth operations. These same volatiles can pose health implications to astronauts and Earth based personnel handling lunar regolith samples. Using Australian, USA and NASA airborne contaminant exposure limits and the Lunar CRater Observation and Sensing Satellite (LCROSS) measurements of lunar volatiles in the Cabeus crater ejecta, the minimum mass of lunar regolith that can be safely handled by humans on Earth and in spacecraft can be calculated. This analysis determined a 0.15 grams pure sample of Cabeus crater regolith within a cubic metre of air has enough volatiles to exceed safe working conditions, and 14.9 grams of pure Cabeus crater regolith per cubic metre of air can impact human life. The intent of this analysis is to assist safe handling and exposure calculations for the safe handling procedures of lunar regolith containing volatiles.

Sep 1, 2024

By Edmonds W, Giles C. W, Webb R. J, Gum J. C

Gold production from The Granites - Tanami Goldfield during 1993 is expected to exceed 8 t, eclipsing that of the traditional Northern Territory gold mining districts of Tennant Creek and Pine Creek. This is the result of dedicated and successful exploration, and the consequent discovery of new orebodies such as those at Dead Bullock Soak.Following granting of access to regional exploration areas in 1988 and identification of favourable host rocks in the Schist Hills area, North Flinders Mines (NFM) began a methodical exploration program of detailed geological mapping, rock chip sampling, costeaning and various types of drilling. The first resource of 600 000 t of 3.3 g/t gold was announced in mid-1989. This has grown progressively with systematic exploration to the currently published resource inventory of 6.6 mT @ 5.4 g/t, (as at 31.12.92) contained in six separate orebodies within the Dead Bullock Soak Mineral Lease at Schist Hills.

Jan 1, 1993

This paper discusses design concepts in planning a large modern bulk terminal. The need is emphasised for a studied master plan, in-built materials handling flexibility and staged development. An integrated approach is advocated, combining functional purpose designed foundations and structures to serve their mechanical, electrical and environmental functions. Dry bulk and slurry handling are also compared in perspective.

Jan 1, 1983

By Dionne S, Goodwin F. E

Zinc-aluminium alloy cast matrix composites have been made by squeeze casting, pressure infiltration, spraying forming and stir casting. The overview describes composites made . with these processes. Improvements in properties compared to the conventional alloys are most significant at elevated temperatures. Since stir casting is the most economical viable route of producing composites, progress made in this area is particularly emphasised.

Jan 1, 1993

When a thin film of volatile matter is deposited under vacuum on a polished coal surface, and the coated surface is examined microscopically in piano--polarized reflected light, colour changes are observed characteristic of the various macerals present. The colour changes appear to be mainly due to interference between light reflected at the upper surface of the film and at the film/coal interface. A variety of source materials for the volatile matter required have been tested, including powdered bituminous coal, coal tars, boron oxide, and certain resins.

Jan 1, 1969

Comparison of the Zadra, Anglo-American and organic solvent procedures for desorption of gold from activated carbon loaded in carbon-in-pulp gold circuits indicates that the Anglo American and the organic solvent procedures are considerably more effective than the commonly used Zadra procedure. Organic solvent elution procedures, particularly those using acetonitrile and acetone, can provide effective gold elution and very high concentrations of gold in eluate solutions. The operational simplicity and effectiveness of the Anglo American procedure would appear to make it the most satisfactory procedure available at the present time but this may change as the solvent elution procedures become better developed. INTRODUCTION The carbon-in-pulp technique has been introduced into the gold processing industry to by-pass the often lengthy CCD and filtration steps required in the conventional Merrill Crowe cyanidation procedure for gold recovery. Adsorption of gold on to carbon is also a valuable technique for recovering trace amounts of gold from low level waste streams from conventional processing procedures.

Jan 1, 1982

The interaction of man with the environment has a double character. From one side, mankind can not exist without co- nsuming the natural resources and, from the other side, we actively alter and exert influence upon nature. Analysis reveals that the ecological problem is, to a great extent, a geological one. The paper deals with the application of grouting techniques to construct impermeable barriers for the protection of ground water and soils from depletion and industrial wastes pollution. A number of case histories in the field of mine construction is given to illustrate the solution of geotechnical problems in concert with environ- mental protection measures.

Jan 1, 1988

By Billington WG

A structural study of northwest Fergusson Island, part of the D'Entrecasteaux Group, was undertaken using colour and monochrome aerial photography and Landsat imagery. The resulting interpretation shows an upstanding, in part, dome-like metamorphic core complex, which is bound on three sides by an en echelon series of low-angle, thrust faults. Faceted gneissic layers occur throughout the complex. These facets are triangular in plan view and range in size from a few tens of metres, to massive composite zones which traverse the entire uplifted zone, The lower surface of each of the facets are, in fact, low-angle decollements which, during uplift, slid one upon the other to accommodate the vertical and extensional movements. As a consequence, deep structural valleys developed which widen towards the zone of maximum uplift. In many places, recognisable topographic features are replicated on both sides of these valleys, and under the stereoscope can be visually reconstructed to their original pre break-up positions. The southern margin of the core complex is less dome-like and falls away, via a series of deeply-entrenched structural valleys, towards a volcano-studded lowland. The lowland appears to belong to a rift or arm, stemming from the more southerly located Goodenough Bay Infrabasin.

Jan 1, 1987

Synthetic seismograms of reflectivity method and some field records available are studied to detect the amplitude anomalies at the interface of the gaothermal reservoir the gas and/or oil boundary, and the underground tunnel. The first arrival of PO wave on the P-SV record are weak and emergent while those of P wave only rotated with respect to an incident angle are clear. This can, be explained by means of the energy loss of P-SV wave conversion. The primary reflections of P waves about depth fade away as compared to SH waves which do not perform any conversion, although they hold high attenuation in the fully saturated fluid layers. Reflection of comparable strength is present at the P-wave and S-wave... boundaries, but gas-saturated zones correlating with P wave bright spots do not show equivalent attenuation anomalies. Thus the comparative technique of P-SV wave and SI i wave records is very useful to indicate the strong amplitude anomalies at the boundaries of sealing targets.

Jan 1, 1990

Most of the gold reef mined today in South Africa is approximately 1 m in width with slopes about 30 m long. To prevent production interruptions it is essential that the stopes should not be blasted in sections. The shortage of experienced labour and arduous working conditions at the face dictate the need for simple blasting techniques.Hence, a pyrotechnic blasting system of sequential firing is in use at present, although research work to improve this technique is in progress.

Jan 1, 1985