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By Kavetsky A, Scott A

As well as breaking and moving rock, blast energy sets up a seismic wave in the ground which can cause significant damage to rock structures and buildings and disturbance to human occupants. This seismic ground vibration is potentially most damaging when its dominant frequency coincides with the resonant frequency of a structure, leading to high amplification factors between the input ground vibration and the resulting structural response. This paper outlines methods of identifying the resonant frequency of structures. It also describes a practical numerical method for the modification of blast designs to reduce the ground vibration energy in critical frequency ranges. The method is illustrated with two recent case studies.

Jan 1, 1990

By G Muller, P Larrondo, M C. Godoy

The categories of Mineral Resources and Ore Reserves that may be used for public reporting in Australasia are defined in the current JORC Code (2004). Most internationally accepted codes emphasise the principles of transparency, materiality and competence in classifying resources. They also provide some guidance in considering the impact of data quality. There is no method recommended in the JORC Code to classify a Mineral Resource into the allowed categories of Measured, Indicated and Inferred for public reporting. A clearly defined procedure is desirable for many reasons, including consistency, repeatability and auditability. The demonstrated use of geological knowledge in the classification method is desirable. In deposits with abundant historical data there can be large variations in data type and quality. Quantification of the error of the estimates may also be considered. Ways to formally incorporate such information into the resource classification process are presented as a first step towards establishing an objective, repeatable methodology that allocates resources into appropriate categories based on defined criteria of accuracy and precision.

Jan 1, 2006

By Orr C. W

Continuing the systematic investigation of the influence of elements on the properties of lead(1). If the effects of additions of copper (up to 0.3%) on Port Pirie lead have now been determined in so far as creep rate is concerned.The results in the present paper contain also a survey of the influence of copper on the micro-structure of lead, a feature which has not appeared in the previous papers of this series. Further, it has now become known that creep is but little related to the more usually determined properties such as hardness and tensile strength. Since, however, these properties are of considerable importance in connection with the fabrication and use of this metal. Brinell hardness determinations have also been made and are here included.It is becoming more and more realised also that to be useful, creep data should refer to stresses of the order of those used in practice. This is due to the fact that as soon as deformation takes place, the properties of the metal are automatically changed. Lead does, of course, creep during industrial use, and probably (in lead chamber construction for example) extensions of the order of 5%...

Jan 1, 1938

By Honey F. R, Furnell R. G, Lyon R. J P

A Joint Venture between Union Oil Development Corporation and Geoscan Proprietary Limited carried out an Airborne Multispectral Scanner Survey over approximately 15,000 square kilometres in the Charters towers area of northeastern Queensland during late 1985 and in September, 1986. The survey, using the Geoscan Mark I scanner, consisted of 50 runs each having a swath width of 5 kilometres. Twelve or thirteen spectral bands were recorded, 5 in the VNIR, 4 in the SWIR and 3 or 4 in the TIR. The results of the survey were interpreted by interactive image processing with the aim of identifying those minerals or their weathering products which are characteristically associated with hydrothermally emplaced gold mineralisation in this part of Queensland. Spectral bands in the VNIR were used to identify and discriminate the iron hydroxides, whilst the SWIR bands were used to outline the clay and carbonate rich areas. The TIR aided in identifying areas of silicification.

Jan 1, 1989

In making any attempts to determine the depositional environments in which coal seams accumulated it would be useful to establish whether there is a pattern, or patterns, of development which the majority of the seams have followed. To this end, the distribution of types of coal seam sequences found in the standard petrographic profiles of about a hundred Australian coal seams of Permian and Triassic age has been examined statistically, using the "chi square test" with the limiting probability set at O·Gl.Results indicate that non-random conditions have probably prevailed during the deposition of most of the seams. More samples are needed for conclusive results.The plants, or some other internal feature of the swamp environment, have been the important controlling factor in the development of the seam sequences.Comparison has been made with some British Carboniferous coals.

Jan 1, 1972

Economies in cemented fill demand the utilisation of the full potential of the portland cement component of the mix. If declined tailings are used, it is desirable to establish the optimum particle size distribution. Pozzolic materials and slags are. very useful additions to increase the amount of cementitious material through reaction with calcium hydroxide produced by hydration of the cement. It is also essential to check out the presence of substances which may seriously affect the setting and hardening of the cement or the durability of the cement bond. The importance of quality control in the preparation of cemented fill cannot be over Emphasised.

Jan 1, 1973

By Bearman R. A, Parkin R. M

Traditional quality control procedures for aggregates production within the quarry industry rely on off-line laboratory analysis, resulting in poor performance and inconsistent product quality. A high speed on-line aggregate classification system is described here. A product sampling system directs aggregate through an inspection chamber where a novel imaging system digitises the particle geometry. Data processing algorithms extract dimensional data and image features, while a neural network classifier assigns a qualitative shape descriptor to each rock particle. This system provides each sampled batch with a complete analysis of size and shape distributions, complementing a new generation of cone crusher technology to maximise product quality and plant efficiency.

Jan 1, 1995

Supergene enrichment of ilmenite occurs through a complex series of reactions with initial oxidation and hydration followed by leaching and dehydration. Lateritization appears to be associated with the early phase of the supergene process and if ilmenite grains are encased in iron oxides no further alteration proceeds.

Jan 1, 1986

This technical note describes a problem with WANG82, a ventilation network analysis programme. The problem was highlighted by Renison Ltd when using the programme on large, complex networks. Under certain circumstances the programme produced incorrect results or failed to converge to a solution.

Jan 1, 1986

Coal geology plays an essential role in the investigation of in situ coal seam quality. Coal geology can also play an important part in laboratory studies such as coal washing and coking, and in operating plant problems.

Jan 1, 1976

By J Tickner, Y Van Haarlem, G Roach, D Abernethy, M Smith, J OÆDwyer

The development of novel technologies capable of real-time, high-accuracy, automated analysis of gold, other precious metals and mineralogy, both in ore samples and directly on process streams is reported.X-ray fluorescence (XRF) analysis is widely used for process stream monitoring of base metals. However, detection limits are generally a few parts-per-million (ppm) or larger, precluding the use of this method for monitoring precious metals. Complex interferences with other elements also limit accuracy. An XRF slurry analyser that uses advanced data-analysis techniques to resolve overlapping fluorescence lines, achieving detection limits in the parts-per-billion (ppb) range has been developed. This allows feed, concentrate and tailings streams in precious metal applications to be monitored in real-time. An extended trial of our technology in a platinum group element concentrator and laboratory tests on gold process slurries in the 0.1 - 2.0 ppm concentration range is discussed.Analysis of process stream mineralogy can provide useful information to supplement conventional elemental data. An on-stream X-ray diffraction analysis technique that provide real-time mineral and elemental measurement of process slurry streams has been developed. Both X-ray techniques can be combined into a single on-stream analyser to provide simultaneous elemental and mineralogical information. The successful trial of a combined XRDF (X-ray diffraction and fluorescence) slurry analyser is also reported.It is widely recognised that rapid, accurate analysis of grade is an essential prerequisite for optimising the efficiency of exploration, mining and processing of metals ores. The low grades of precious metals ores, such as gold and the platinum group elements, have led to fire assay becoming the predominant analysis technique. Significant drawbacks of fire assay include long turn-around times, limited absolute accuracy, high costs and requirement for skilled operating staff. For rapid measurement of gold samples, a technique that allows the gold content of large samples to be determined absolutely with high accuracy in less than two minutes using activation with high-energy X-rays has been developed. The method is non-destructive, has detection limits in the low ppb range, is capable of measuring slurries, ground or crushed solids with minimal preparation and can be made fully automatic. Initial results from laboratory trials are presented.CITATION:Roach, G, Abernethy, D, OÆDwyer, J, Smith, M, Tickner, J and Van Haarlem, Y, 2013. Advanced instrumentation for analysis of exploration, mining and process materials, in Proceedings World Gold 2013 , pp 277-282 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

The patterns of flow of reaction gases through the flash furnace at the Kalgoorlie Nickel Smelter were simulated in a 1:20 scale model using a flow of water. Particular features of the flow down the reaction shaft, through the settling chamber and into the uptake leading to the waste-heat boiler were examined. Inferences were made concerning the effects of the patterns of flow on the efficiency of the smelting reaction, on the entrainment of dust by the gas stream and on the erosion of the refractory lining of the furnace. In addition, the effects of geometrical modifications to the arrangement of the concentrate burners and to the profile of the settling chamber were explored by making these changes to the model and observing the resulting variations in the patterns of flow.

Jan 1, 1991

A very sensitive high-speed two-colour pyrometer was built to measure the temperature of single particles of sulphide mineral, typi- cally 50 pm in diameter, as they burnt while entrained in a hot gas stream. The pyrometer has been used to study the burning of pyrite and chalcopyrite particles and has thrown light on cenosphere formation. Measured maxi- mum temperatures have been compared with values predicted by diffusion-based models. The pyrometer has also been used to study the burning of small captive pellets (2-9 mmm dia- meter) of lead-zinc concentrate.

Jan 1, 1984

Poorly designed sampling protocols generally result in high project risk by artificially increasing grade variability (ie the nugget effect). Sample collection, preparation and assay protocols that suit the ore type, together with QA/QC systems, will reduce this risk. All reporting codes (eg JORC, 2004) require the Competent Person to consider the quality and implication of sampling and assaying programs. High sampling errors beget higher project uncertainty; despite this fact, sampling does not receive the attention it deserves. The case studies presented show that many sampling issues frequently go unrecognised or unaddressed, resulting in poor project decisions during exploration through to feasibility and production. The overall conclusion is that correct sampling is critical to mining project success and that there is often a need for its optimisation.

Jan 1, 2007

WMC Resources Ltd has been involved the development and trialling of an automated load haul dump vehicle system since 1997. This paper describes the introduction of the system into the Olympic Dam Operation and its performance compared with existing manual loaders. In certain situations the autotram loader will outperform the manual operation, particularly on the longer distances. There were no personnel injuries associated with the operation of the system during the testing period.

Jan 1, 2005

This paper will present a series of examples drawn for a number of Australian and international mining companies showing their recent attempts at optimisation of capital. The results will be compared, contrasted and discussed in the light of six factors that are considered crucial to any analysis of this subject. The factors are: ò the market availability of capital ò the corporate strategy and performance ò the capital structure appropriate to the corporate positioning within the industry ò the parties to the optimisation equation ò the measurement of success of optimisation The factors above are not mutually exclusive and are generally interdependent so their order above is of little consequence. Other papers presented at this conference will dwell in more depth on all these factors, therefore this paper shall focus only on the key elements of each factor. By way of summary this paper will also address the issue of the longevity of optimisation - is it temporary or long term.

Jan 1, 1991

By Buizen M

An investigation into the mechanics of sub-surface deformation caused by caving of the extracted area behind retreating longwall faces has been completed by the Subsidence Engineering Section of the New South Wales (NSW) Department of Minerals and Energy. Changes in strata bulk permeability were also measured by standard packer tests undertaken before and after mining. The strata movement was measured by a multi-wire borehole instrumentation system consisting of mechanical anchors installed at different horizons in a borehole extending from the surface to the coal seam. The mechanical anchors were collected to suspended weights on the surface by stainless steel multi-strand wires. The movement of these weights was monitored as the longwall face approached and retreated past the borehole. The anchors did not move significantly until the face went past the borehole. For subcritical extraction geometry with the extraction width to mining depth ratio of 124, the caving zone extended to roughly 9 times the extracted seam thickness above the seam roof. Tensile strains within the overburden tended to be much more closely related to stratigraphy than to the proximity to the extracted seam roof. Larger tensile strains were associated with layers of sandstone, siltstone and conglomerate, whereas layers of mudstones, claystones and coal underwent much smaller strains indicating subsidence in blocks. A beller correlation was observed between pre-mining Rock Quality Designation and permeability than between rock type and permeability. This correlation was less evident in the post-mining core logs. There was an overall increase in bulk permeability after mining.

Jan 1, 1990

By Cooper R. J

The essential features of the zinc concentrate roasting installation at the Risdon Works by the Electrolytic Zinc Company of Australasia Ltd. are given.The problem of maintenance of ignition in down-draught zinc concentrate flash roasters is discussed, and a solution offered.A successful and economical method of using by-product oxygen for raising the roasting efficiency of hearth roasters is described. Three methods of utilizing oxygen for the same purpose in flash roasting are detailed, and their relative merit, considered.INTRODUCTIONThe zinc sulphide concentrate used at the Risdon Works is roasted autogenously for removal of sulphur in two hearth roasters, and four flash roasters. The hearth roasters are of modified Skinner type with eleven hearths. They were designed, and are used, for roasting mixtures of relatively low sulphide content. Their design and operation have been described elsewhere (Forster, 1949).The flash roasters are down-draughted furnaces with cross-section and rabbling equipment based on the hearth roaster design, and the process is similar to that developed by the Consolidated Mining and Smelting Company of Canada Ltd. (Cominco) at Trail, B.C. (Stimmel, Hannay, and McBean, 1936).These furnaces are 20 ft. in diameter. They have three drying hearths through which hot gas is drawn from the combustion chamber by the burner fan. The combustion chamber is 2'1 ft. high above the collecting hearth (27 ft. in No. 4 unit), and the discharge hearth below it is 6 ft. high, so that a large gas offtake is possible. Four rabble arms for each hearth are carried on a central column. Dried, ground concentrate, and the air for roasting it, are fed to a burner...

Jan 1, 1958

By King D, Dickinson S. B, Matheson R. S

Commencing in 1956, Rio TInto Australian Exploration Pty Limited in association with Electrolytic Zinc Co of Australasia, Limited, has been carrying out a mineral prospecting program in North-West Tasmania over an area of about 4000 square miles.The program has comprised extensive airborne geophysical surveys, detailed geological mapping, ground geophysical and geochemical investigations. Out of the wealth of new data, and the examination of previous records, has emerged a new structural concept of regional ore control and distribution in North-West Tasmania. This roncept stems from the discovery of an ancient 'fossil' rift valley (graben), named the Owen Rift Valley, along which are located the major mines of the area and numerous well-known prospects. The known mines and prospects from north to south include Mt Bischoff (tin); the Pinnacles (zinc, lead, ropper); the Chester (pyrites); Rosebery-Hercules (lead, zinc, ropper, silver, gold); Mt Tyndall (lead, ropper, zinc); Comstock and Tasman (copper, lead, zinc); Mt Lyell (copper, pyrites, gold); Mt Jukes and Mt Darwin (ropper). The identification of the West Coast (Owen Conglomerate) Range as a fossil rift valley is due to Or B Campana, who carried out extensive geological mapping and interpretation work, and who, with S B Dickinson, are the senior authors of this paper.S B Dickinson, who introduced B Campana to the geological problems of West Tasmania, had previously investigated the Mt Lyell and Rosebery mining fIeld, to which reference is made in this work.D King assisted in the regional mapping and in providing numerous data on the mineral distribution of the area.R S Matheson rontributed to the fmdings on ore emplacement and rontrol in the discussions held on this subject. They are accordingly included as joint authors of this paper.Credit is also due to E McCarthy, who interpreted the geophysical results, and to J H Rattigan, who compiled the preliminary geological maps from published documents and by photo-geological methods.G Hall and V H Cottle, of the Electrolytic Zinc Co in Rosebery, provided invaluable geological data and suggestions in the course of the survey, and made a constructive criticism of the manuscript of this work. The airborne geophysical survey carried out by the Adastra-Hunting Geophysics Ltd company, furnished useful data which substantiated many of the fIndings on the stratigraphic and structural relationship. The Mines Department of Tasmania and S W Carey, Professor of Geology at the University of Tasmania, were instrumental in initiating the regional survey and provided the published and unpublished geological literature on the area.The authors also wish to acknowledge the invaluable assistance received from the Mt Lyell Mining and Railway Co in Queenstown, which made available the more recent geological and mining documents rompiled by M L Wade and M Solomon.

Jan 1, 1994

It is no longer satisfactory to assess the value of a coking coal on its intrinsic properties alone; its value depends upon its behaviour as a component in a blend. No single test can be used to make this assessment, it can only be made by carrying out a suite of tests. The quality parameters which are considered desirable, and which have widespread acceptance, have been discussed and their application to the blending of coals from New South Wales and New Zealand has been reported and discussed. Blending can be utilised to offset deficiencies, or capitalise on advantages, of the individual coals making up a blend. Coals can be blended, which alone are poorly, Coking, but which have compensating features. Blending also allows better exploitation of coking coal reserves. Several applications of blending have been reviewed with regard to coal producers and exporters, as well as coal users. The possibility of extracting a coking coal fraction from fuel coals is discussed. Blending systems and the coking of coal are also briefly reviewed.

Jan 1, 1971