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Electromagnetic methods used in geo- physical prospecting for conductive ore bodies have proved successful in Canada,Sweden and other countries. In Australia however the depth of weathering generally exceeds 30 metres. This introduces a problem of highly conductive overburden and renders equipment useful elsewhere virtually ineffective. A discussion of several EM prospecting techniques is presented and a new system under development at James Cook University using V.L.F. transmissions capable of indicating changes in impedance (not only highly conducting media) is outlined.

Jan 1, 1974

By Bolton G. C

Experiments were conducted to access the feasibility of removing zinc from lead slag by sulfation or chlorination or both. Gaseous sulfation with sulfur dioxide and oxygen released only 50 per cent of zinc even under the most severe conditions. Sulfation with concentrated sulfuric acid by a fast-leach process released 95 per cent of zinc while pug-roasting released a maximum of 78 per cent of zinc. Chloridization with NaCi in the presence of sulfating gas released 50 per cent of zinc, while direct chlorination with chlorine gas and oxygen released 85 per cent of zinc and 100 per cent of lead in a chloride condensate containing little impurities.

Jan 1, 1980

By R Pie, J Crusius, P Whittle, J J. McNee

The Main Zone and Waterline pit lakes at the Equity Silver Mine near Houston, BC (Canada) are the sites of an ongoing three-year government- and industry-funded research program. In order to assess the feasibility of various bio-remediation strategies, field-scale manipulations were conducted using enclosed mesocosms (limnocorrals). Two manipulation strategies were tested: addition of algal nutrients (phosphate and nitrate) to Main Zone Pit surface waters; and addition of algal nutrients (surface waters) and dissolved organic carbon (deep waters) to the Waterline Pit. Nutrient addition was conducted in order to stimulate algal production and enhance metal scavenging by biogenic particles, while dissolved organic carbon (ethanol) was added to increase oxygen demand and foster the development of sulfate reduction in pit bottom waters. Fertilisation resulted in rapid growth of natural phytoplankton populations in the surface waters of both pits. In the Main Zone Pit, the stimulation of algal growth resulted in the pronounced removal of both dissolved and total metals (Zn and Cu) from surface waters, with higher rates of metal removal being observed at higher nutrient additions. Metal removal could be attributed to the scavenging of dissolved metals by biogenic particles and subsequent particle settling. A similar pattern of removal from surface waters was observed in Waterline Pit (Zn and Cd). The addition of ethanol to deep waters in Waterline Pit was effective in promoting sulfate reduction in the lower layer. The development of reducing conditions resulted in near-quantitative removal of dissolved Zn and Cd, presumably as secondary metal sulfides. Iron, As and Ni profiles in Waterline Pit exhibited no evidence of removal from either surface waters or bottom waters. Collectively, the results demonstrate that the passive forms of bioremediation tested in these pit lakes may be effective for whole pit-lake remediation.

Jan 1, 2003

BECAUSE of the attention given in recent years to the flotation process, there is an extensive range of equipment available to any staff detailed for: the design of a flotation mill. This statement applies not only to the flotation machines, but also to equipment for crushing and grinding, elevating the pulp, dehydrating of concentrates, and the methods of driving the various equipment.Distributed through the Proceedings and Transactions of various metallurgical societies and journals there are many excellent descriptions of flotation mills, their equipment and performance.Whilst these articles describe-in many cases in detail-the equipment in the mills to which they refer, the reasons which govern the choice of each particular equipment are not usually given.

Jan 1, 1929

By P Fines, D J. Williams, G W, S Miller

This paper presents the results and findings of geochemical and mineralogical testwork conducted on samples collected from waste rock dumps at two mine sites, located in South Carolina, USA (Site 1) and Sudbury Ontario, Canada (Site 2). Important aspects of the relationship between the physical and geochemical aspects of the dumps are also presented. The overall aims of the project were to 1. determine if the physical and hydrological nature of the waste-rock dumps had any impact on the geochemical and mineralogical characteristics of the dump materials; and 2. to identify key implications for dump construction for ARD control. The results of geochemical and mineralogical tests indicate that the waste rock at Site 1 had undergone significant in-dump weathering and was relatively advanced with respect to ARD evolution. In contrast, the waste rock at Site 2 had undergone some weathering, however still contained a considerable amount of sulfide minerals. Testing also suggested that flushing of oxidation products at Site 2 had been limited, which therefore promoted the storage of oxidation products at the site. In addition, materials that had a D50 particle size in the range of 5 mm to 30 mm appeared to be more readily flushed than samples that had a D50 particle size of 30 mm. This suggested that preferential water pathways may have developed within the dumps at both sites.

Jan 1, 2003

A study of the effect of nickel on the cupellation process has shown that a very low "nickel limit" must be imposed for cupellation (0·08 grams nickel or 0·05 grams when copper is present). In the presence of slightly greater amounts of nickel, lead tends to spreadon the cupel with detachment of drops from the main lead pool. In crucible fusions nickel contaminates the lead button to a small extent, and this contamination is increased.in the presence of either iron or copper. Nickel also causes "shotting" of the lead, this effect being more apparent in the presence of iron.Both the spreading during cupellation and the shotting during crucible fusion are considered to be caused by adsorption of insoluble NiO at the Pb-PbO interface, lowering the interfacial tension.Excess litharge crucible charges are' fused at 116boC. to eliminate shotting. A brief· soaking in molten basic litharge slag effectively reduces the nickel content of lead buttons. The solubility of silver in litharge slags is considerably decreased in the presence of nickel. Corrections can be applied for silver losses in slags but these corrections are not as accurate as with copper ores.INTRODUCTIONThis paper on the effects of nickel on fire assays for silver is the second of an intended series describing investigations into the fire assaying method.In the first paper, discussing the effect of copper on fire assaying processes (Guerin, 1957), it was shown that certain elements, because of their relatively low affinities for oxygen, will tend to contaminate the lead button during crucible fusion and scorification. Nickel, having a slightly greater affinity for oxygen than has lead, would be expected to be oxidized and slagged readily, and would not be expected to appear in the metal phase (lead button) to any appreciable extent. Thus, judged solely on this basis of...

Jan 1, 1960

By R M. Hough, G Duclaux, M A. Pearce, M F. Gazley

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Microcharacterisation, such as that described in this paper, provides understanding of a mineral system at multiple scales, and understanding microscale variations is the key to understanding the large-scale variations in a mineral system. More than 50 high-grade lode samples from across Plutonic Gold Mine (Plutonic), Marymia Inlier, Western Australia were analysed by a variety of techniques, including micro X-ray fluorescence (µXRF) mapping, micro X-ray computed tomography (µCT), scanning electron microscopy (SEM), field emission gun SEM, electron back-scatter detector (EBSD), proton-induced X-ray emission microprobe and synchrotron XRF mapping. These data demonstrate that competency contrasts are the key to governing the location of Au mineralisation at Plutonic. Micro CT imaging of high-grade samples shows the Au filling in voids and pore-space in the rock, after having travelled along more permeable layers and already existing or reaction-induced pores formed during hydrothermal circulation. Using 3D visualisation, the Au is seen to form a connected network that appears undisturbed at the scale of the samples, and a high-grade Au deposition event was one of the last events to affect the rock. This interpretation is supported by SEM analyses on high-grade samples that reveal calc-silicate (epidote-clinozoisite) alteration that is not present in lower Au grade samples, which are typically dominated by potassic alteration, and that sulfides are typically less abundant close to the Au. The replacement of biotite by chlorite is an alteration associated with the high-grade Au-mineralising fluid. Gold is coarsest where Au particles are located on the margins of minerals, typically sulfide and quartz grains, suggesting the importance of rheological contrast at the microscale. Furthermore, EBSD data reveals that Au is undeformed and overprints peak metamorphic and retrograde minerals. Data confirm recent deposit-scale observations, suggesting that deposition of high-grade, visible Au was related to a hydrothermal fluid circulation event late in the geological history of Plutonic.CITATION:Gazley, M F, Duclaux, G, Fisher, L A, Hough, R M and Pearce, M A, 2015. High-resolution characterisation of gold mineralisation at Plutonic Gold Mine, Western Australia – evidence for the late-stage deposition of high-grade gold , in Proceedings PACRIM 2015 Congress, pp 51–58 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By Crosby N. R

The design of mine openings and the assessment of their reserve are processes ihicl, require the routine manipulation of considerable amounts of data. A number of computer programs have been assembled to operate in a mini computer in order to provide some mechanical assistance for these processes. The system responds to plain language commands. which allows mining engineers to compute the reserves for a number of possible mining outlines, on an interactive basis. Methods of numerical analysis were used in preference to statistical or qeostatistical techniques.

Jan 1, 1977

By Bof J, Lowe S

BHP's newest colliery on the Southern Coalfield Is Tower Colliery. It is situated near Wilton some 60 kms south west from Sydney. It commenced its operations in 1978 and since that time has experienced considerable roof problems. In its eight years of operations, production has been 936 687 tonnes to December 1985. To a certain extent this is a reflection of the ground control r,,b1cros present in the colliery. paper out Iines the signif mt g,, logical features that are known to exist in the colliery and their influence on roadway development. Faulting has hindered the mine's development and an igneous intrusion has had outhursting associated with it. The prevailing roof rock has also had an impact on the roadway conditions. The paper will look at intersection deformation in present workings. Extensometers have been installed in these areas and provide measurements to verify visual observations. The results show a significant increase in roof movement as the roadway is developed from a single heading, to a T-intersection and then Into a four-way intersection.

Jan 1, 1986

By S E. Box, J L. Mauk

The Middle Proterozoic metasedimentary rocks of the Belt Supergroup contain important metallic mineral deposits like the diagenetic sediment-hosted stratiform copper mineralization, including the Troy (Spar Lake) deposit and the epigenetic hydrothermal veins in the lower Belt and Ravalli Group in the Coeur d'Alene district. Magnetite (Fe3O4) is a common and widespread accessory mineral in these rocks and can have multiple origins including ore stage in deposits, mobilization stage in source rocks, metamorphism of red beds and alteration mineral in thin halos enveloping Ag-rich veins in the Coeur dÆAlene district. As shown in several classic studies, the composition of magnetite from igneous rocks varies significantly in response to controlling factors such as melt composition, temperature, silica activity, and oxygen and sulphur fugacity. Therefore, the distinctively different geologic settings within the Belt Supergroup strongly suggest that there may be differences in the magnetite compositions. However, initial microprobe analyses detected no variation in magnetite composition.   Three possibilities may give an adequate explanation for these initial results: 1.      the magnetite formed primarily as pure Fe3O4, 2.      one or more tectonothermal events led to regional scale re-equilibration that affected all rocks in the field area, and 3.      the variations in the composition are below the detection limit of the microprobe.

Jan 1, 2007

By Filmer AO

In contrast to the '50s and '60s, the period of the '80s and '90s seems likely to have low growth in demand but much greater levels of technological change. In such a climate there will be pressure on costs, productivity will continue to rise and competitiveness will be closely associated with maintenance of the most effective technology. The penalties for inappropriate investments, whether short sighted or mistakenly based on a particular view of the future, will be greatly enhanced. Accordingly, there will be a need for significantly improved anticipation of technical change and thus for better planning. Study of the funding and direction of the world's R&D effort can provide a useful input to the planning processes within industries and individual firms. Such a study also suggests some insights into the characteristics of those countries which have achieved substantial growth and high standards of living over the past two decades. These characteristics may offer significant reminders for our own development. The particular implications for the Australian minerals industry include the need for direction that is sensitive to changing market requirements and customer practice. This is not simply "more of the same." In particular it appears essential for both basic and applied R&D to provide a sound basis for the purchase and ongoing development of the new technology required to achieve international Competitiveness.

Jan 1, 1986

Mining of the silver-lead-zinc orebodies at the George Fisher Mine officially started in 2000. A review of mining performance to date shows that many of the extracted primary stopes have experienced some degree of hangingwall dilution. The degree of hangingwall failure in the stopes became progressively more extensive throughout mining of the orebodies in 2001 and 2002, culminating in the unplanned catastrophic failure of the 744D stope in which the ore between 13C (2683RL) and 12L (2714RL) sublevels caved into the previously mined cavity between 13L (2654RL) and 13C sublevels. This was followed several months later by another unplanned caving event in a nearby stope, 740D. As a direct result of these unplanned failures it was decided to mine the stopes with a smaller span than had been previously planned and in a primary-secondary pyramidal stoping sequence. To limit the exposure of the stope hangingwall, a hangingwall drive is no longer developed and therefore geologists no longer have access to the detailed geological information that this provided. Geologists at George Fisher Mine have had to be adaptable and flexible in response to these proposed changes and rely more on data from drilling than mapping for their geological interpretation. The result is that the drilling cycle has become much more critical in the planning process.

Jan 1, 2003

By Postupack C

A major problem that has continued to plague the surface and underground coal industries is blast induced damage to the coal seam. Blasting Analysis International, in conjunction with a number of other organizations, has continued to address this concern through 14 years of field research in 68 full-scale production environments worldwide. Compiled results were obtained from varying field conditions. These included single and multiple seam coal mines, horizontal, rolling and steeply dipping coal seams and varied borehole diameters (ranging from 102 to 381 mm) and when using various explosive formulations. Results are discussed in detail along with the tools, test methods and analysis techniques to identify and quantify the problems. Over ten major causes of coal damage were identified. A number of practical and economic recommendations are presented that can benefit the entire coal and blasting industry especially in commercial operations whose economic growth relies heavily upon recovering an undamaged coal seam.

Jan 1, 1995

By Singh RN

Monolithic packing systems have gained in popularity as a gate side packing method. However, there has been no detailed investigation to assess their underground strength behaviour. This work includes the laboratory and in situ investigation for strength behaviour determined on various monolithic packing materials namely Tekpak-XX, Hydropak-20, Hydropak-30, Astrapak-3R, Flashpak, Thyssen pack and Aquablends. A simple technique for assessing the pack strength was developed at the laboratory by using a penetrometer, of which penetration resistance can be directly correlated with the uniaxial strength of the pack. The in situ strength investigations were made on core samples obtained from three pipes inserted inside the pack, while the penetration test were made on the pack surface. The in situ results indicated that the packing material develops an inconsistent strength on various part of the pack which was mainly related to an inadequate mixing of grouts inside the pack.

Jan 1, 1992

A number of suggestions have been made to improve the design of cells used for electro winning and electro refining of metals. Most of these designs have been aimed at increasing the current density used in order to improve cell capacity, although the purpose of some has been to produce electro deposited metals in a continuous manner. Improvements in the electrolyte flow pattern in conventional cells have resulted in an increase in the rate of mass transport of metal ions to the electrode surface; giving rise to lower concentrat- ion polarization and an improvement in the nature of the product obtained, Other cell designs are based on a moving electrode, usually a rotating disk, and these may include provision for removal of the product in a continuous manner, The maximum current density which can be used in an electro- lytic deposition process is determined by the limiting diffusion current, the physical nature of the, product, the purity of the product required and by the increase in power costs which result from the higher cell voltages, This paper examines the properties of an agitated bed of particles as an electrode system when used for a metal deposition Process,

Jan 1, 1969

By W J

Al ores arriving at the works which contain more than 3% sulphur, together with all sands and other fine residues, are delivered to the roasting department. Those that are in a coarse condition are first sent to the crushing plant, consisting of 15 in. x 9 in. jaw crushers and two No. 5 Krupp mills. The ore is here crushed through a quarter mesh screen. Any pyritic concentrates high in sulphur are given a preliminary roasting, to bring the sulphur contents down to about 12 % and the roasted material is delivered to the H. H. charge-making bins. Here the various ores, sands, residues, roasted pyrites, together with about 12 % of limestone, are made up into I-ton charges in hopper trucks with bottom discharge. The trucks are elevated by hydraulic lifts to a tramway running over the roasting furnaces, and the contents are dropped into hoppers over each furnace, from whence the mixture is fed into the centre of each furnace by means of a Challenge ore-feeder.

Jan 1, 1918

By Koppe J. C

This study presents the procedure of mine modelling and reserve evaluation by means of statistics, computer interpolation methods and aerophotography interpretation. All data are from Carbonifera Treviso, Laura Muller City, Santa Catarina State, southernmost Brazil. From 22 bore holes and nine trenches opened in the coal seam outcrops, a data base including level references and thickness of all rock formations was created.Using this information, basic statistic analysis was carried out, showing that there are three different populations (three modal distribution). These populations defined three geological blocks with different characteristics of overburden removal and mining methodology. This mathematical approach for analysing geological data is very important for correct mine planning and complementary prospection.

Jan 1, 1993

A simple production technique has been initiated and implemented at Oaky Creek open cut coal mine to optimise recovery of coal from the relatively thin geological seams. The production technique is based upon minimising coal dilution through careful dragline operation and the selective use of mine mobile equipment to clean the top of coal. In addition, recovery of coal from the pits has been increased by refining blasting and dragline methods.The implementation of the recovery optimisation programme at Oaky Creek has provided significant economic benefits from increased yield through the preparation plant by the reduction in dilution, and from increased raw coal tonnage through improved pit recovery methods.

Jan 1, 1990

By P Pelletier, J Tessier, C Duchesne

This paper summarises research into the study of the control of flotation processes based on froth images. A review of the froth flotation operation background and the relevance and role of the froth phase are presented. The use of numerical image analysis techniques for the extraction of significant patterns from industrial flotation froths is discussed. First, the froth was analysed by the use of the multivariate image analysis (MIA) method to extract the spectral variation contained in a RBG image. The partial least squares (PLS) method was applied to develop an empirical model for the prediction of froth grade. The results of this application are illustrated using an industrial case study. Second, the froth was also analysed by grey-level co-occurrence matrix (GLCM) and wavelet transform analysis (WTA) to extract features related more to morphological aspects. Since there is useful information hidden in froth texture, these methods are used as texture descriptor to classify different types of froths. They also provide qualitative information on the changes in the visual appearance of the froth. The pros and the cons of those methods are highlighted. Third, a control strategy based on a froth structure indicator was developed and implemented on an industrial zinc flotation circuit. The feedback controller uses the reagent flow-rate in order to maintain the froth structure at its set point. Process improvements obtained from the implemented control strategy are highlighted. Finally, the feasibility of implementing a hybrid control strategy consisting in a froth structure supervision controller based on the froth concentrate grade estimated by MIA and recovery inferred by image analysis is discussed.

Jan 1, 2005

By Jancar T, de Guzman M M, Matthews B, Tu J. Y

The use of computational simulation to predict the performance of existing equipment or for the design of improved mineral processing equipment will be referred to as Computational Mineral Processing (CMP) in this paper. The emphasis will be on solving the governing equations for liquid solid flows in complex geometric domains to obtain, typically, the three-dimensional distributions of velocity and pressure for the liquid phase and the velocity and concentration for the solid phase. The underlying technology, computational fluid dynamics (CFD), is very well-developed in other industries (aircraft, car and chemical) and forms a vital part of product design and analysis. The subsequent design of improved mineral processing equipment may also involve finite element structural analysis (FESA). Computational fluid dynamics (CFD) and finite element structural analysis (FESA) are part of the generic discipline of Computational Engineering and Science (CES). Ciment and Scherlis (1993) define CES as `The systematic application of computing systems and computational solution techniques to mathematical models formulated to describe and simulate phenomena of scientific and engineering interest'. Increasing computer power (Kaufmann and Smarr, 1993), is a dominant factor determining the rapid growth of industrial utilisation of CES. This increase is happening at both the supercomputer and the workstation level. Indeed, today's typical workstation, a Hewlett-Packard 735, is as powerful as a CDC 7600, the leading supercomputer in 1970. Future computer architectures are expected to become increasingly parallel (Gartner Group, 1990) allowing a sustained performance of a teraflop (a million megaflops) to be achieved well before the Sydney Olympics in the year 2000. It is recognised that the modem development of most disciplines in the physical sciences rests on the three complementary strategies of experimentation, analysis and computational simulation. As the 21st century is approached the volume of computational simulation, both fundamental and applied, is growing dramatically and the role of experimentation is diminishing. In the area of equipment design, CES provides the following advantages over experimental testing and measurement: 1. lead time in design and development is significantly reduced; 2. CES can simulate conditions not reproducible in experimental tests; 3. CES provides detailed and comprehensive information; and 4. CES is more cost-effective and time-efficient. The ultimate benefit for industry is greater productivity and hence greater profitability. The broader issues in relation to CFD are discussed by Fletcher (1993b). In the five- to ten-year time frame, growth in computer power will make it practical to combine CFD and FESA with optimisation procedures to produce a design process that is almost fully computerised. It is expected that fully automatic

Jan 1, 1995