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A biological column leach testwork program was undertaken on a chalcocite ore. Three tests were conducted in all, using 65 in x 100 mm columns in three sections. The tests were started with varying acid strengths and inoculated with bacterial solutions from previous column testwork. The leaching of Cu was found to occur in three stages. These stages consisted of direct acid leaching, bacterial oxidation and ferric iron leaching. These leaching stages can most easily he described through the examination of not only Cu dissolution but also Fe dissolution and its subsequent oxidation and precipitation. The p11 of the system was found to he critical in establishing and maintaining the bacterial leaching system. The oxidation potential was seen to he influenced by the leaching system as the oxidation states altered. Test variables such as, 02, COz, and temperature were all found to influence the system. Final copper recoveries were in excess of 90 per cent in each column test over a leach time ranging from 211 to 328 days. Given similar leach conditions are applied, the application of this technology to site is expected to give comparable results.

Jan 1, 1994

By J Rowland, B Belle, M Webber

The Australian underground coal industry has experienced substantial improvements in longwall productivity and, as such, the methods of providing a safe and productive mine environment have needed to evolve and develop. Whilst the primary method of controlling atmospheric conditions is by airflow it has become impracticable or impossible for the majority of Australian longwall mines to contend with all environmental hazards with primary ventilation alone.If the ventilation circuit cannot provide a safe and productive mine environment at an acceptable cost and circuit duty then supplementary controls are required. Examples include pre-gas drainage, post-gas drainage, gas utilisation, refrigeration and innovative dust control systems. Of the 21 longwall operations surveyed in Australia, there were 13 in New South Wales and eight in Queensland.This study represents a timely opportunity for the industry to examine the primary and supplementary ventilation systems implemented in Australian longwall mines and to discuss how to equip the industry to successfully face the future of underground longwall ventilation management in Australia.CITATION:Webber, M, Belle, B and Rowland, J, 2017. Australian longwall ventilation systems, in Proceedings Australian Mine Vent Conference 2017, pp 301–308 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

The mineralogy, maero- and micro-textures of Thackaringa ore are simple and have many counterparts among base metal-quartz-siderite vein type deposits elsewhere.The ore consists predominantly of galena, sphalerlte, chalcopyrite, tetrahedrite, and arsenopyrite in a quartz and siderite gangue. Silver minerals, as such, appear to be lacking and silver values are no higher than in other sulphide ores of this type. These features contrast very markedly with those of the A.B.H. Consols Lode which appears to have emanated from the north end of the Broken Hill Main Lode Horizon during high grade regional metamorphism. The Consols Lode has been regarded as of Thackaringa type, and both are regarded as possibly arising from the remobilization of Main Lode Horizon ore. Whilst this may yet prove to be so it appears that the marked differences in mineral composition between the Consols and the Thackaringa types, would require somewhat different modes of regeneration.Thackaringa ore, as well as A.B.H. Consols ore, on this basis, would necessitate the development of a metahydrothermal ore fluid to account for their present apparently hydrothermal (or pseudo-hydrothermal) constitution...

Jan 1, 1967

By Perring CS, Vearncombe J. R, Ho SE, Groves DI

Large Late Archaean greenstone belts in Western Australia, Canada and Zimbabwe, contain abundant mesothermal gold, volcanogenic massive base-metal sulphide, and komatiite-associated Ni-Cu mineralization. These greenstone belts are similar in many respects to convergent and accretionary plate margins found in the Pacific rim; modem environments which are cor-respondingly rich in gold and base-metal mineralization. The giant gold placer deposits of the Late Archaean Witwatersrand Basin (the world's largest gold producer) formed in a foreland or retro-arc basin; in a similar tectonic setting to much modem placer mineralization around the Pacific. Gold and volcanogenic base-metal sulphide mineralization are abundant in Late Archaean terranes and the Pacific rim because1. gold mineralization is a product of convergent margin tectonics, and 2. accretion in convergent margin orogens provides the best chance of preserving base-metal mineralization related to submarine volcanism.It is therefore likely that the abundance of gold and base-metal sulphide mineralization in the Late Archaean reflects the widespread growth and sta-bilization of continental crust via tectonic processes broadly similar to those operating in the present Pacific basin.

Jan 1, 1990

By McCarthy P. L

A distinctive feature of the goldfields of Victoria was the extrac- tion of gold from deep leads, that is the buried river beds of Vic- toria's ancient rivers and streams. It is estimated that about 265,000 kg of gold was produced from Victoria's deep lead mines which comprises about 11.5% of Victoria's total production of gold (Bowen, 1974). The significance of deep lead mining for Victoria, however, went far beyond its economic contribution to Victoria. If Profes- sor Blainey is correct it was the frustrations of mining gold from deep alluvial leads in Ballarat during 1854 which precipitated the Eureka Stockade (Blainey, 1963, 46-52). This event resulted in the implementation of a fair mining administration and was an emphatic statement of the rise of democratic movements in Australia. Much of the technology and skill for mining deep leads had to be developed locally because at that time no other major gold- field elsewhere in Australia or the world had gold deposits with comparable problems. Deep lead mining in Victoria was there- fore largely a home grown industry and the equipment for that industry was often designed and produced in Victoria.

Jan 1, 1988

By Eren H

For a hydrocyclone of fIXed geometry, DC, Di, DO and ? are constants, the variable parameters affecting the performance are Qi, Fi, Du and H. (See Appendix 2 for definition of symbols).The relationship between d50c, Qi, Fi, Du and H gives models which can effectively be used for performance predictions. Such models have already been established by Lynch et al and by Plitt.These models have been tried in a limited manner under continuous operating conditions for on-line cowol. For on-line control effective and accurate instrumentation is required for which a new set up is proposed. Using this set up, a new model was established. A feature in this model is that deviations from the norm of operational parameters affecting d50c were considered. It is shown that these deviations generated by the disturbance of one or more of variations in the parameters, can be monitored by a computer and suitable signals generated to control servo mechanisms for restoring the required d50c value.The logic followed in developing the computer software is described and the application of the model is indicated.

Jan 1, 1990

By Savidis G

The characteristics of 'Z' (Back-over run) and 'R' (Reverse) ventilation systems are dis- cussed in relation to their suitability for longwall mining. Experience in European mines has been described as a basis for comparison with Australian conditions. In assessing the merits of each ventilat- ion system, such factors as longwall layout (pillar design, number of headings and gateroad stability), the need for gas drainage and bleed- er systems, as well as the influence of seam dip have been considered relevant. The R system is generally applicable for single and two heading development in seams where gas emission is a less serious problem. In contrast, the lower extraction to development ratio of the Z system (which arises from using three or more heading layouts) is considered more favourable where high gas emission occurs. The Z system provides greater flexibility with respect to the provision of refreshing air at the tailgate end, access of men and materials, installation and retrieval of gas drainage systems and the ability to interchange main- gate and tailgate roadways in cases where roof strata loads are difficult to control, or where cpam in hac an influrnra

Jan 1, 1983

This paper discusses the use of tapered roller bearings in conveyor idlers. It shows that in medium and high capacity systems, tapered roller bearings can offer significant cost and performance advantages. In the next ten years, conventional conveyors will face increased competition from unconventional belt conveyors, pneumatic systems, pipeline "slurry" systems, unit trains and so on. The conveyor industry must meet these challenges by innova- tive use of technology. Conventional belt conveyors must continue to show the lowest cost per tonne-km or lose their position in the market. Tapered roller bearings can contribute to the achievement of this goal. The concurrent resources boom and liquid fuel crises may well see a decline in the use of heavy trucks for bulk material handling over moderate distances 10 to 50 km. There appears to be a trend in the conveyor industry to go to higher speeds with improved belting in conven- tional widths. The transmission of more material over a given period of time will place more demands on conveyor idler bearings. Australia has in general followed the European practice of using deep groove ball bearings in conveyor idlers.

Jan 1, 1978

By Hall J. S, Zuiderwyk M, Reid A. F

A prototype version of a computer controll- ed on-line scanning electron microscope image analyser, employing the real-time signals ob tamed by digital control of the electron beam has been used to obtain statistical quantificat lion of a wide range of mineral grain character istics, including composition, size distribut- ion, and degree of liberation. These propert lies have been determined for suites of whole particles of flotation concentrates, mounted without further preparation. The facility is also well adapted to the measurement of general Istereological parameters. The computer control software is based on an operating system which includes the device drivers and which is linked to FORTRAN programs [containing the procedural algorithms. The beam scanner provides a 4000 x 4000 point raster swept at a 10 Mhz rate in steps of 1 to 200 points and a set of up to 8 signal channels which respond to electron or energy dispersive X-ray signals to provide a digital attern.characterizing the sample composition. the beam is stepped at high speed until a part- 'cle or phase boundary is encountered; a longer well time is set if X-ray data is required. he digital scanner interrupts the computer

Jan 1, 1977

By J K. Claflin, S R. La Brooy, A M. Claflin

Rotary kilns have been in service in the gold industry to regenerate carbon for 65 years. At the time oxide ores with gold head grades of 8 to 10 g/t were being treated. Carbon could be regenerated adequately at 650°C and solution losses were less than 1%. Forty years ago, research indicated that heavily fouled carbon from flotation circuits had to be held at 750 to 850°C for ten to twenty minutes for full reactivation (Avraamides and La Brooy, 1987), gold head grades were typically 5 g/t and solution losses typically 0.02 ppm – still less than 1%. In 2017 it was determined (Claflin et al., 2017) that a residence time of less than 1 minute at 750°C can be adequate to reactivate carbon fouled with organics sufficiently to achieve 0.005 ppm solution losses in a flotation tailings leach plant.With the potential for discovery head grades to drop below 0.6 g/t, solution losses of 0.02 ppm represent over 3% loss. Tight operation of the whole carbon circuit is required to keep gold solution losses below 1% going forward.There are alternatives to a rotary carbon kiln, e.g. vertical kilns of which the Minfurn, Rintoul and Combustion Air kilns are examples. The alternative kilns can be heated using electrical heating elements, induction, and microwave. These kilns can operate successfully under the right conditions, however, they are almost exclusively for small carbon throughputs and are not suitable for the large carbon advance rates that are required to process low head grade ore deposits. Large throughput carbon kilns are are almost exclusively fossil fuel fired rotary kilns and the subject of this paper. In the view of the principal author, a fossil fuel fired vertical carbon kiln is preferred to a rotary kiln, however, it is not currently used in the industry.Thermal regeneration of activated carbon has a major impact on gold recovery in the carbon circuit. The carbon kiln and associated equipment constitute 3 to 5% of the capital cost for an oxide processing plant and up to 10% of the capital cost if flotation tails are leached. Despite the capital cost and impact on recovery, the carbon kiln is often poorly selected, operated and maintained.Six years ago Ausenco embarked on the Carbon Kiln Initiative to reduce solution gold losses. This body of knowledge has been published in a series of papers culminating in this paper on how to:1. Select a kiln appropriate for the flowsheet;2. Maintain the kiln to achieve design operation; and3. Operate the kiln to minimise costs and maximise reactivation.CITATION:Claflin, J K, La Brooy, S R and Claflin, A M, 2018. Carbon kiln selection, operation and maintenance, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 251–274 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By Russell P

Polyurethane resin (PUR) is extensively used in almost all coal producing countries. On the local scene, PUR components suitable for underground application were selected and subsequently, trials were carried out at several coal mines. This paper describes the work at Pikes Gully Colliery (B.P.3Coal), where water flow rates of up to 4.5 m (1000 gallons) per minute, were reduced to 1-1.5 m /minute at the tirst stage of application. Subsequent trials were carried out at West Cliff Colliery (Kembla Coal and Coke). A variety of PUR chemical mixtures were tested in coal ribs and in the roof of intersections and roadways. The trial results are presented with all particular details. Using the PUR injection method, the roof, at the most difficult intersection, was stabilised and 'de-bonded' roof bolts were re-sealed. At Pikes Gully and West Cliff Collieries, 2 tonnes and 3 tonnes of PUR chemicals were injected, respectively. The technique, primarily based on German experience (Bergwerksverband), was used by Delta Control Systems Pty. Ltd. ACIRL was closely associated with the trials, which were monitored by installation of the measuring Stations.

Jan 1, 1986

By Gyasi-Agyei Y

In recent years rapid advances have been made in the technology used for hydrology and erosion modelling of rural catchments. These advances have been driven by the growing availability of digital terrain maps that can be used to automatically define catchment properties that previously had to be manually extracted from contour maps. In addition, these models have, in principle at least, more powerful predictive capability. The author is involved in a number of projects to migrate and further develop these models for application to mine rehabilitation assessment. Current technologies for hydrology and erosion assessment (eg CREAMS, ANSWERS) are reviewed, underlying principles highlighted and deficiencies in the context of mine rehabilitation design assessment addressed. The advantages and disadvantages of the new digital terrain map tools (eg WEPP, SIBERIA) are discussed. Current work integrating these new models with existing rehabilitation design tools (eg ACIRL's ARGUS computer package) highlights the advantages of an integrated approach using digital terrain maps; cheaper, faster, lower impact and more flexible rehabilitation design. The use of novel visualisation tools to aid the design process is discussed. The paper is illustrated by applications to mine sites in Queensland and the Northern Territory.

Jan 1, 1995

Supergene nickel sulphide ore mined currently by Agnew Mining Company is at times partially oxidised to sulphate. The resulting soluble nickel, and calcium and magnesium in mill water, are shown to act as depressants in flotation. The depressant effect is favourably selective in that violarite, the main nickel mineral, is less affected than pyrrhotite. Nickel recovery, however, is adversely affected, probably through reduced flotation of complex sulphides. Soda ash consumption is increased markedly by the presence of the cations as shown by operating data and pulp titration tests. A significant increase in concentrate grade, from 9% to 14% Ni, was achieved late in 1981. One of the changes in plant practice which contributed to this improvement was the addition of soda ash to mill feed rather than to flotation feed as before. It is shown by laboratory tests that this reduced the depressant effects of the cations, thereby improving recovery at the expense of rougher selectivity, or equivalently, increasing concentrate grade at constant recovery. The selective depressant effect cannot be exploited until scavenger recovery is improved and a scavenger concentrate regrind-retreat äcircuit is implemented. Development is

Jan 1, 1978

The excessively high cost of production in underground coal mines has made the survival of many coal mines around the globe economically non-viable. The global competitive coal market speaks itself of the desirability of a lower operating cost in conjunction with a higher productivity performance, particularly in underground coal mines, and calls for an optimal production planning under a host of constraints. Such a task of optimal planning is not an easy exercise like that of traditional planning based merely on intuition, experience and subjective judgement. It essentially demands a thorough understanding of the complex interaction of mine sub-systems for judicious application of optimisation tools and techniques available with operations research. A few large mines around the globe have made an effective use of a sizeable number of operations research packaged programs for optimal decision-making (Grayson, 1989). The success of practical applications of operations research techniques made in a variety of mining problems in large mines in different parts of the world will hopefully make inroads to smaller mines in years to come. The present paper is an addition in the series of such applications of operations research tools to mining problems, particularly with reference to an underground coal mine in India. The paper is based on research work (Jawed, 1990) and deals with the development and use of a mathematical model for production planning in underground coal mines under multiple objective environment subject to a host of constraints.

Jan 1, 1995

By P Ormsby, T Hewitt

Ore in pillars constitutes a significant proportion of the ore reserve at PasmincoÆs Broken Hill Mine. Many of these pillars are narrow (5 -6 m) and high (16 û 35 m) vertical blocks. High-grade ore has been left between primary horizontal cut and fill stopes. These stopes were mined from the late-1960s until the early-1980s. Fill material is a variety of hydraulically stowed sand, sand-cement, and remnant timber support. Many pillar cut-throughs were made between the old stopes. In order to gain access for the current pillar recovery operations, it has been necessary to develop pillar drill drives through, and adjacent to, the hydraulic filled stopes. Whilst long hole recovery of vertical pillars is not new, some notable successes using innovative ideas have been achieved during 1997. These innovations include:The use of steel mesh reinforcing in shotcrete when mining through, or adjacent to, hydraulic fill. Construction of steel sets to support vent rises and haulage ways encountered in the cut-throughs. The use of ground movement monitoring equipment. Survey lasers with chain droppers and convergence monitors were installed in the 18 Pillar to detect any movement of the pillar block and decrease risk to personnel. The development of a three-dimensional computer model of primary stoping, using Vulcan software, to assist in the design of pillars. Maximisation of recovery using different drilling and firing practices.

Jan 1, 1998

A comprehensive understanding of the rocks associated with coal seams, and also of the coal itself, is essential in assessing the likely behaviour of the materials before, during and after the mining process. The nature of the rock materials involved in coal mining can give rise to risks from adverse geomechanical properties, create problems in coal quality control and produce difficulties with environmental impacts, all of which may affect the profitability, impact and safety of the operation. Examples of issues associated with rock composition include slaking and degradation leading to roof, floor, pit wall or spoil pile instability, ignition of methane in mine atmospheres by frictional processes, liberation of quartz-rich dusts into ventilation systems, production of coal with unfavourable preparation or marketing characteristics, and escape of suspended solids or potentially toxic leachates from spoil piles and other types of emplacements. Methods for evaluating rock composition include microscopic examination, chemical analysis and X-ray diffraction, with the latter being especially useful for fine-grained rocks or for clay-bearing materials. Other techniques, such as geomechanical testing and down-hole geophysical logging, are also useful, but give less direct information about the actual composition of the materials involved. Indeed, understanding of rock composition, through microscope or quantitative X-ray diffraction studies, provides a basis for checking information from other sources, explaining different aspects of rock behaviour, and an essential link in relating geophysical or geotechnical data to broader-based geological models as part of the risk assessment process.

Jan 1, 2003

By Sparrow G. J

In a recently completed AMIRA project, 20 samples were searched for gold mineralisation using the automated location facility (ALF) for rare phases on a scanning electron microscope in the CSIRO Division of Mineral Products, Melbourne. The samples were submitted by mining companies in Australia, and Papua New Guinea, and included crushed ore samples, cyclone overflow and underflow products, a flotation concentrate, and 12 tailing samples. Their gold contents ranged from 600 to 0.2 g/t An. Native gold and gold minerals including a gold telluride, gold-silver tellurides, and a gold bismuth mineral, were located in the samples as free grains and associated with other minerals such as pyrite, magnetite, hematite, ankerite, copper sulphides, silicate minerals, and quartz. In the highest grade samples, both micron sized and 200 ¦m grains of gold were found with ALF. It would be difficult to locate such d wide size range of gold in a manual search. Gold mineralisation was located in the tailing samples assaying 0.4 g/t An and higher. In several tailing samples coarse grains of native gold over 40 p.m in size were located. One grain was estimated to have contributed 40 per cent of the gold in the sample. As well as locating gold mineralisation, the ALF examination resulted in the identification of uranium, mercury, and bismuth minerals in the samples. Knowledge of the distribution of these minerals in processing streams could be important in the operation of a concentrator.

Jan 1, 1992

By Parsons A. E

The application of known pelletizing tech- nology was successful in the agglomeration of zinc concentrate into pellets of minus 6mm siz- ing using fine zinc calcine and sulphuric acid as binder. Subsequent roasting trials conducted in a 0.3 m diameter fluid bed reactor, showed that the pellets satisfactorily withstood hot physical abrasion during fluidization. Fines generation was low and the pellet calcine was hard, possessing excellent handling properties. Results of laboratory scale static pellet sinter- ing tests showed conclusively that the deterior- ation in sinter physical quality experienced with fine calcine was not apparent when the calcine was added to the mix in pellet form. Based on the results of small scale exper- imental work, a one tonne per hour pilot plant was constructed and operated. Several thousand tonne of pellets were produced-for fluid bed roasting in Badische Analin and Soda Fabrik (B.A.S.F.) turbulent layer (T.L.) roasters previously designed for roasting iron pyrite concentrate. Continuity of the T.L. fluid bed roasting operations was achieved when the waste heat boilers were replaced with atmospheric coolers and thus eliminated the problems of gas flow restrictions. Sinter plant trials were conducted over a period of two weeks with the addition of pellet calcine to the sinter feed. Results showed a marked improvement in sinter plant performance, and as a result of better bed permeability, increased sinter production was achieved, with- out significant deterioration in sinter quality.

Jan 1, 1974

Optimising drill performance has always been a primary goal of drilling and blasting managers. Improving drilling rates and utilisation will ultimately drive the cost per foot or metre downward. Additionally, more consistent production will ensure shovel or dragline performance goals are met and the chances of machine idle time is minimised. Over the past 20 years, many studies have examined rotary drilling factors and performance issues. In most cases a common theory points to energy input versus drilling output. Indexes such as specific energy and total work energy have been -developed to quantify the drilling process. As general engineering principles dictate, energy is required to drill rock by overcoming compressive and shear strengths. Concurrently, the greater the energy input, the faster the penetration output. Therefore, by examining the basic drilling energy parameters, optimisation is possible. The principles of rotary drilling are driven by five factors. When optimised individually and as a system, drill performance will improve. Most recent studies all agree that a performance relationship exists between bit load, bit rotation, and hole flushing. Additionally, proper bit selection and most of all, the operator, can have a tremendous effect on drill productivity. By analysing these factors and establishing the best case scenario, an overall drilling system can be engineered to match the mining characteristics. Furthermore, by balancing these factors, a lower cost will be achieved through increased production rates, maintenance costs, and effective drill utilisation.

Jan 1, 1995

By Lewis W. H, Leigh M. C, Mayercheck W. D

The U. S. Department of Interior's Bureau of Mines, in conjunction with a cooperator in the U. S. A., are developing a new highwall mining system (HMS) for coal extraction in unreclaimed and active contour strip mines. This prototype system is comprised of a computer-based remote control (CBRC) system to monitor and remotely control a thin-seam continuous miner (TSCM) and a 76*m long multiple-unit continuous haulage (MUCH) conveying system, plus other manually- operated support equipment located on the highwall bench. The TSCM and MUCH coal haulage system are both controlled remotely by a single operator in a protective enclosure at an ergonomically- designed workstation located on the highwall bench. Two other personnel work on the bench to operate other support equipment. Full-scale mock-up fabrications were employed in the design of the unique remote control operator workstation. The HMS should allow the safe and economical exploitation of increased coal reserves where they outcrop in hilly regions of the United States. It should also be competitive with conventional auger mining and other coal extraction techniques, with a productivity goal at a highwall site of 20 tonne/man-h. Extensive simulated surface tests of the miner and haulage system should be completed in early 1988 at Bureau test facilities at Pittsburgh, Pennsylvania. These will be followed by actual coal production trials of the entire system in 1988 at a highwall site in West Virginia/USA.

Jan 1, 1988