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By S N CARRAS

Ore reserve estimation is a procedure involving data collection, data storage and judgement and assumptions about geology mining and metallurgy. Calculations are based on these assumptions and an economic analysis on projected cash flows is carried out. Ore reserve estimation must therefore be subjective and will always depend on the extent to which the assumptions used in arriving at the estimate are correct. This paper is an attempt to summarise the many aspects that can contribute to ore reserve problems and to offer some suggestions on how to minimise these problems. For further details on specific concepts readers are referred to the detailed descriptions in the referenced papers.

Jan 1, 1992

This paper discusses how the i-kon TM Digital Energy Control System may be deployed by miners of massive underground orebodies to deliver significant advantage in terms of safety, cost and environmental compliance. Digital Energy Control offers an exciting opportunity for mine operators to review their blasting and mining practice to gain the most advantage from this new technology.

Jan 1, 2000

Discovery 2000 is basically about data, its collection, management, assessment and dissemination. A major focus of Discovery 2000 is the collection of new geoscientific data. However, the Department is already a major source of data on the geology and mineral resources of New South Wales. These existing data when combined with the new data, will greatly enhance the knowledge of and information on the geology and the mineral development potential of New South Wales. This paper discusses some of the existing datasets and outlines how they can be accessed. It also gives an insight into the Department's strategy for data and information technology management.

Jan 1, 1995

Much of the data required for the evaluation of mine design is obtained from bore cores. It is essential to collect data that is useful and not to overlook features which might have adverse effects upon the mining practices and which might not be readily discernible to the untrained eye when examining bore cores. Interpretation of the data has progressed from the use of single-value properties, such as ultimate compressive strength or Young's modulus, to the utilisation of most measurable quantities. The simulation techniques used employ physical and mathematical models for prediction of mining conditions or strata behaviour. The application and capabilities of these methods to mine design are discussed.

Jan 1, 1977

The use of econometric models to assess the effects of a Government's policy on an industry is gaining momentum. This is particularly so for the Mineral Industry and it is important that mineral industry management understands the techniques involved in developing econometric models. Models are usually constructed outside the industry by either government departments or their consultants and used by the policy makers to investigate artificially the implementation and ramifications of new policies. This paper discusses the application of econometric models in Governmental policy determination, highlights the use of various models in Australia and gives an overview of the techniques involved using Australian examples.

Jan 1, 1982

By Reifenstein A

ACIRL's petrographers apply microscopic techniques to coal exploration, production, preparation and processing problems and research investigations as well as provide a commercial service for quality control of export coal shipments. This paper describes a number of case studies of applications of petrography to coal industry problems and coal research, including

Jan 1, 1989

By Gadd D. E

Since October 1972, New Zealand Steel Mining Ltd has loaded around 10 million tonnes of ironsand concentrate from single-point mooring buoys located off-shore at Taharoa on the west coast of the North Island of New Zealand. Before the first off-shore loading system was installed a considerable research effort was applied to proving the slurry loading technique. Subsequently the system has been expanded and a new buoy, pipelines and pumping system were installed in early 1978. Since then 110,000 DWT class ore carriers have been loaded at rates of around 2600 tonnes per hour through twin submarine pipelines. This paper reviews the operation of the shiploading system and attempts to answer the question: "If the Taharoa operation were to be planned in 1980, would the same research spending be necessary or have published research results since, made such practical tests unnecessary?".

Jan 1, 1980

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

Many of the discrepancies that appear when comparing the results of reducing machinery are due to the nature of the materials reduced and the conditions under which they have been treated. It is therefore necessary that manufacturers should employ standard materials in their tests that sufficiently approximate the substances to be ultimately treated if the information is to be of any value to the purchaser. Another advantage to be gained by employing universal standard materials is that by their means one is enabled to compare the relative values of different types of machines. At present much of the data meted out to the public is insufficient to enable them to judge fairly. Of course the best test would be to send some of the stone tor which the machine is required, to be treated by the various crushers in the market that are likely to be suitable for the purpose, but this is not always possible. It would not take long to become accustomed to judge of the value of a machine for a specific purpose if it was guaranteed to work a certain quantity of some standard rock, even if that standard were not identical with the material to be treated.There are many points to be considered before selecting a machine, such as the size of the rough stone it will take, the size to which it will reduce it the proportions of various grades made when crushing to pass through a given mesh the form of the delivered particles the time taken to treat a+ certain quantity the horse-power required to drive the machine, both when loaded and unloaded whether constructed to crush wet or dry the wear and tear of the machine its total weight and weight of the heaviest part the cost of machine what attention it required whether the wearing parts are readily replaced, and several other points common to all machinery. 'When considering these varying quantities, we can tell at a glance certain machines that are suitable for a particular sort of work, and can then compare those belonging to the same class, thus avoiding errors made purposely or through ignotance by persons interested in different machines, who frequently compare machines originally constructed for.

By Totterdell JM

The Permian-Triassic Bowen Basin and the Jurassic-Cretaceous Surat Basin evolved in a backarc tectonic setting behind an active convergent plate margin in eastern Gondwana. Several extensional (Early Permian; Eocene) and contractional (mid- Permian; Early Triassic; Middle-Late Triassic; early Late Cretaceous) intraplate deformational events are recognised in the basins. These can be correlated with similar events in the New England Orogen that was being deformed in the Late Permian- Late Triassic as a foreland thrust belt. The intraplate deformations were probably the consequence of plate interactions, including the accretion of terranes, at the ancient active plate margin, remnants of which now occur in New Zealand.

Jan 1, 1995

Twelve years ago, Jeffrey Mining Machinery Division of Dresser Industries Inc. developed the 120H HELIMINER. This machine was the world's first fixed-drum continuous miner and soon became the standard among manufacturers of continuous miners throughout the mining machinery industry. This paper will first outline a brief history of continuous miner development, then discuss significant parameters which are essential to a successful continuous miner design, and finally describe a number of specific applications of Jeffrey continuous miners in a variety of materials, such as coal, potash, iron ore, and trona, around the world.

Jan 1, 1978

By Meunier G, Davis J, Koperski G

The dry processing of mineral sands concentrates can result in the generation of significant amounts of airborne dust. The radioactive component of this dust has implications within the context of work environment health codes. The last four years have seen considerable investment in dry plant equipment enclosure and dust extraction systems, with resultant reductions in plant ambient dust levels. Simultaneously, an industry wide program was started to examine the origin, nature, mineralogy and radioactivity of the airborne dust. The major findings of this study have been: ò confirmation that monazite was the only significant source of dust radioactivity. ò recognition of two sources of dust: - agglomerates of finely divided ilmenite-rutile alteration products, which are formed by the removal of surface coatings and particles. - abraded mineral fragments, which reflect the mineralogy of the parent particles.

Jan 1, 1991

By Mauk JL, McOnie A, Simmons SF

Three cross sections, 200 m apart, display the distribution of indicator hydrothermal minerals across the Empire zone of the Golden Cross epithermal Au-Ag deposit, Waihi, New Zealand. These minerals are used to interpret the temperature and composition of hydrothermal fluids. The distribution of interstratified illite-montmorillonite and illite indicate that temperatures ranged from 140 to >220¦C, with temperatures above 220¦C predominating. The mineral assemblage of quartz-adularia-chlorite-illite-calcite-pyrite envelops the Empire vein system and stockwork, and reflects formation from an alkali chloride water, whereas the mineral assemblage of replacement calcite-interstratified illite - montmorillonite- kaolinite forms a carapace and reflects formation from a C02-rich steam-heated water. Alkali chloride waters appear responsible for the epithermal Au-Ag mineralisation.

Jan 1, 1995

By Bartrop S. B

Mount Isa mine has a long history of successful exploration since discovery 70 years ago. Remaining reserves, although substantial, exist in a scheduling framework which involves long-term production from new ore sources with attendant technical risk and major capital investment. Current exploration aims to incrementally increase reserve tonnage to maintain existing production levels as well as to provide a buffer for potential start-up delays from new ore sources. Exploration also aims to increase the net present value of the operation by discovering new major orebodies around the Mount Isa and Hilton mines.

Jan 1, 1993

Electron paramagnetic resonance provides a fast method to characterise quartz. Quartz from veins associated with the Cambrian massive sulphide deposits in the Mt Read Volcanics of western Tasmania and from Devonian reefs associated with gold mineralisa- tion at various localities in Tasmania exhibit specific EPR patterns, different from quartz from common veins. The intensity of the EPR spectra of the quartz can be used as a statistical guide to gold mineralisation at Beaconsfield.

Jan 1, 1987

In October 1993 it was decided to undertake the fourth phase of mining at Big Bell. This decision followed the exhaustion of open pit reserves in January 1993. Two stages of mining were proposed for the new underground mine. The initial stage would mine the remnant ore, consisting of the rib and crown pillars and lower grade ore on the hangingwall and footwall side of the old open stopes, which were mined from the 1930s to 1950s. Most of the old open stopes were backfilled with either deslimed mill tailings or development mullock, both of which were economic to recover. However, the mineable ore from this resource was difficult to evaluate. The second stage focused on mining ore outside the remnant areas and was initially proposed as a Core and Shell method under a caving hangingwall. This method has since been superseded with sublevel caving, in part due to the very high and deviatoric stress conditions encountered at Big Bell and the relatively long mining cycle required for open stoping. The problems and challenges discussed in this paper will cover the identification of remnant ore reserves, dewatering the old workings, and remnant mining.

Jan 1, 1998

Cyanide is a significant contributor to the cost of producing gold. Any reduction in cyanide consumption that is achieved through more reliable measurement, and/or more efficient management of cyanide dosing rates, can produce a significant financial saving to the mine operation.

Jan 1, 1997

By N F. Glenn, S Thiruchittampalam, B P. Banerjee, S Raval

The determination of shear strength parameters for the spoil material plays a crucial role in the assessment of a dump’s stability; nevertheless, their evaluation necessitates laborious laboratory experiments. In order to address this issue, Simmons and McManus (2004) formulated a framework that serves as a foundation for categorising spoils according to their distinctive shear strength parameters based on observable and tactile characteristics. This framework, previously identified as the ‘BHP Mitsubishi Alliance Coal (BMAC) Spoil Shear Strength Framework’, is now recognised as the ‘CoalSpoil’ framework. The spoil characterisation provided by the CoalSpoil framework offers benefits but is not without limitations. The examination of these attributes in the field is a time-consuming task that demands expertise. Subjectivity arises in the spoil characterisation when attributes straddle the line between two categories, such as delineating matrix-supported and framework-supported fabric structures. To enhance consistency in the spoil characterisation process, minimising human intervention is crucial to mitigate bias, classification errors, and safety risks. This study seeks to achieve this aim by introducing image-assisted and automated methods for spoil characterisation.

Sep 1, 2024

This paper explains why the valuation of mining assets is often a very different exercise from the valuation of the shares in the mining company which owns those assets. The fundamental reason for this is that mining assets, and the shares of the company which owns those assets have different risks. In order to properly value mining securities it is essential to: ò ensure all the different risks and other factors which impact on the value of the mining assets and the value of the shares are taken into account; and determine the extent to which the different risks and other factors are addressed in the value of the mining assets and the value of the shares so as to avoid double counting or not counting at all. If the alternative, but far from consensus, view is accepted that the correct valuation methodology to apply to shares in mining companies should be based on option pricing theory then conventional valuation practice of both mining assets and shares in mining companies will need to be fundamentally reassessed.

Jan 1, 1994

Methods of measuring the frictional properties of rock surfaces, both by direct sliding and in triaxial apparatus, are described. It was found that for some rocks the coefficient of friction remains reasonably constant as sliding is continued but for others it increases considerably.The effect of fluid pressure in the surface of sliding was found in all cases to be adequately represented by the effective stress criterion. Some observations on sliding on two conjugate planes showed that the motion on the two planes may be very different, depending on small differences in the constraints.The coefficients of friction of natural open joints in bore core were found to lie in the comparatively narrow range 0.32 to O.68 although surface coatings were very diverse.A set of diagrams on the equal area projection is given which enables a rapid determination to be made of those planes on which sliding is possible in a given three-dimensional stress field. The influence of the intermediate principal stress on this is of considerable importance.

Jan 1, 1969