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Before commencing design of a coal prepar ation plant, it is essential to have detailed information of the raw coal to be treated to- gether with a clear understanding of the products required. Prediction of raw coal size distribution, particularly the amount of fine material, is difficult and the methods employed should be large scale pilot plant studies or techniques to simulate coal degradation and shale breakdown in water. A detailed knowledge of well proven coal preparation processes and new developments allows processes and process combinations to be compared to'obtain the maximum economic recovery when using lower cost, less efficient processes within acceptable limits. Equipment should be selected bearing in mind its precise application and the location where it is installed. Plant layout should be carefully studied to minimise equipment requirements and to simplify construction. Measurement, control and automation should be an integral part of plant design in order to obtain the optimum performance of the processing equipment.

Jan 1, 1974

Investigations of the Mineragraphic Section; Commonwealth Scientific and Industrial Research Organisation, have included most of the known stannite-bearing ores in Australia, and have revealed several new occurrences of this relatively uncommon mineral. They provide information about its paragenesis, and its possible effect on tin recovery, that may be of general interest.Several of the investigations used in the preparation of this paper, were made in the first instance by pr. F. L. Stillwell or in collaboration with him.CASSITERITE-SULPHIDE ORES IN NORTH-WEST- TASMANIA Stannite is a minor component of most of the cassiterite sulphide ores of north-western Tasmania. These include the orebodies of Mount Bischoff, the Cleveland mine, Moina, the Stanley River district, Renison Bell, and the Heemskirk-Zeehan district, and form a well defined metallogenetic provence which is related to the Devonian granites of this part of Tasmania.In these ores mineralisation began. with deposition of cassiterite, a little wolfram, and quartz, topaz and tourmaline. With falling temperature, deposition of cassiterite ceased and arsenopy-rite, pyrite, and especially pyrrhotite, formed in abundance, tending to give massive sulphide ore. A little chalcopyrite; stannite, sphalerite and native bismuth accompanied the pyrrhotite. Deposition of quartz ceased after the pyrrhotite, was formed, and the later-formed nonsulphide gangue consists chiefly of carbonates and fluorite. With, the advent of the carbonates the pyrrhotite was altered to fine-gained intergrowths of marcasite and pyrite. Excess iron from the pyrrhotite entered the intergrown carbonate, or was precipitated as magnetite. Some solution of the cassiterite occurred at this stage, the tin being redeposited chiefly as stimnite replacement rims around the residual cassitellrite grains. Varying, but small, amounts of sphalerite, galena, tetrahedrite and silver minerals were depoSited at this stage, bringing the mineralisation to a...

Jan 1, 1951

By Espinosa-Gomez R, Johnson NW

The Copper Concentrator at Mount Isa Mines Limited treats on average 18 000 tonnes/day of chalcopyrite ore containing typically three per cent copper. The main gangue minerals are iron sulphides (-13 per cent) and non sulphide gangue (-78 per cent). In August, 1991, the comminution flowsheet was changed from a conventional circuit (crusher/rod mill/two stage ball milling) to a modem circuit (fully autogenous grinding/one stage ball milling). The 80 per cent passing size of the flotation feed with the conventional circuit was 125 microns. The Copper Concentrator has two parallel grinding lines, two roughing and scavenging flotation lines, and common cleaning, recleaning and retreatment sections. During the first six weeks of the installation phase, one of the two flotation lines was fed by the conventional grinding circuit and the other by the autogenous grinding circuit. Data from parallel surveys and historical data are used to analyse the rougher/scavenger flotation performance before and after the change. The solid and mineral distributions of the flotation feed, the pulp chemistry and the reagent requirements are compared. The mineral liberation before and after the installation of autogenous grinding is compared on a sized basis using data from the 14 consecutive months before, and the seven months after the change. Liberation was measured using the QEM*SEM(*) instrument. The overall effect of the new grinding circuit on the plant metallurgy is also assessed using the copper recovery values, the dilution of the final concentrate and the distribution of copper losses in the final tailings. (*) Quantitative Evaluation of Materials by Scanning Electron Microscopy

Jan 1, 1993

By J Abols, T Hughes

The selective recovery of gold and silver from solutions containing other metals, such as copper, is possible using AuRIX«100 resin in conjunction with the Gekko Resin Column. Selectivity is driven by controlling the solution pH, which enables activities such as loading copper, gold and silver and then selectively stripping copper before gold and silver. Alternatively gold and silver can be loaded and the copper left in solution. The selective loading of gold while reducing the silver loading has also been demonstrated, opening the possibility of producing high grade gold dorT from high grade silver pregnant leach solutions. This paper reviews the AuRIX«100 resin and Gekko Resin Column Technologies, discusses the uses of AuRIX«100 in the recovery of gold and silver and the chemistry relating to several projects for which AuRIX«100 is being tested.

Jan 1, 2005

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 Churchill M

One of the significant changes which has occurred in the flotation sector of the minerals industry, over the last two decades, has been the successful development of the very large flotation machine. The last twenty years has seen the volume of the individual cell, available to the industry, increase by a factor of ten. Today, new mills, and existing mill modernization plans, can consider individual cell volumes as large as 85 m3 with the certainty that the metallurgical performance capability of the large machine is inherently as efficient as the smaller machine. The large flotation cell offers benefits to the user such as reduced floor space, lower total power, process control simplification, and reduced maintenance. However, the flotation machine size selection process, based on overall installation economics, must include such factors as process tonnage, flotation kinetics characteristics, and metallurgical performance objectives. This paper discusses the flotation machine size and circuit arrangement selection based on both metallurgical performance and economic considerations. A computer based flotation kinetic analysis technique, which has proven valuable in quantifying the metallurgical response of flotation circuits having different cell sizes and number, is utilized to illustrate the selection of cell size and arrangement best suited to a client's Requirement.

Jan 1, 1991

By Spencer PA, Winborne DA

The Porgera mineral deposit in Papua-New Guinea contains gold as finely divided, probably submicroscopic (1 um) particles dispersed in a pyrite sulphide matrix. Only 25-30% of the gold in pyrite can be extracted by direct cyanide leaching and fine grinding the pyrite does not increase gold extraction significantly. This work is concerned with the application of alkaline leaching at atmospheric pressure to oxidise the pyrite prior to gold recovery by cyanidation. The paper presents and discusses results of a comprehensive set of testwork using sodium carbonate, sodium hydroxide and calcium hydroxide alkaline media. Best results, at 60-70% gold extraction, were obtained with sodium hydroxide systems.

Jan 1, 1984

Through the stress synthesis of many exanples of macrostructure from eastern to western parts of China, it can be concluded that in Chinese tectonics there are two push- twisting forces, one of which ("Rl", from SE to NW) came from the Pacific Ocean plate thrusting over the Chinese continent plate in the eastern part of China; the other ("R2", from SW to NE) resulted from the thrusting of the India plate. The meeting line could be situated along the belt from 104¦-106¦E longitude in the middle part of China. To the south of Qinling the meeting line was an abyssal and giant fault situated from Longmen to the Er Inland Sea where the Tibet-Gansi fold system was intersqueezed to the Sidluan platform; to the north of Qinling, situated on the Fengxiang subsidence of the Eerduosi basin, the meeting line was located about 105¦E in Mongolia and appeared in the form of an arcuate structure, i.e. the Mongolia arcuate structure, which could extend to Beijiaer Lake towards the north. A new special type of structure named rotation-apart structure occurred from Gansu, Qinghai province to Ningxia, Neimeng autonomous region, in the west of Shandong province and in the western part of Chaidamu Basin.

Jan 1, 1987

By Getliffe RK

It is becoming more and more difficult to operate mineral and metal processes profitably, as operating costs rise, quality demands in-crease, international competition becomes more fierce and Government charges remain at their current levels. Profitability today depends upon efficient operations, which can only be achieved through precise and dependable con-trol of each process unit comprising thetotal plant.Modern process control systems utilise distributed architecture with microprocessor-based controllers, data acquisition devices and VDU operator stations. Honeywell intro-duced this control technology in 1975 with the "Total Distributed Control" System. Now, building on the proven performance and re-liability inherent in TDC hiway modules, Honeywell has extended the TDC system to inte-grate both management information and control by providing distributed processing modules on the new TDC 3000 Local Control Network (LCN).

Jan 1, 1985

By Hatherly P, Luo X, Balusu R, Gale W

Ongoing, collaborative research between CSIRO's Exploration and Mining and Strata Control Technology has resulted in a better understanding of rock failure mechanisms around longwall extraction. Failure has occurred further ahead of the retreating face than predicted by conventional longwall geomechanics theory. In some cases significant failure has been detected several hundred metres ahead of the face position with demonstrated influences of minor geological discontinuities. Shear, rather than tensile failure has been the predominant failure mechanism in the environments monitored. Validating technologies of microseismic monitoring and new face monitoring techniques have assisted the development of predictive 2D computational modelling tools. The demonstrated 3D consequences of failure has assisted in the ongoing direction of the project to further investigate these effects.

Jan 1, 1998

By Kurihara M

In Japan, shield tunneling method is generally used to drive a tunnel in sand layers around the urban area. In this report, appli- cability of NATM (New Austrian Tunnelling Method), which uses rock bolts and shotcrete as support, to water-bearing sand layers is studied aiming at establishing more economical tunnel driving technique. After the geological exploration, the conditions (i.e. pitch of steel supports, water content, cohesion, and fine content of ground,)necessary to ensure the face stability were investigated by using centrifuge loading tests. Concerning measures to manage ground water, an air permiability test was carried out to investigate the effect of the compressed air to cut-off inflow, and pumping test to study the applicability of dewatering. Furthermore, two dimensional elastic FEM analysis consider- ing progress of the excavation face was perform- ed to analyze stresses in the support system and deformation of the ground, and to investi- gate safety of the support and the ground. From these prior investigations, possibility of the applicability of NATM to the present pro- ject was predicted. Finally, based on these results, a real scale field application test was put into practice to confirm the prediction, and to pursue construction efficiency and phenomena which could not have been predicted Beforehand.

Jan 1, 1987

Maps of mineral grade used to assess mineral reserves are most commonly generated using one of the many estimation methods available such as inverse distance weighting or ordinary kriging. Most such maps incorporate a degree of spatial smoothing which is an integral part of the averaging process. In deposits with highly variable grade which include many gold deposits, this smoothing can mask the detailed geometry of the mineralization at the economic cutoff grades being considered. In underground mining, a knowledge of this geometry is important in the choice of mining method and thus in the assessment of the minable reserves.The method of conditional simulation in geostatistics can be used to generate maps of grade which reflect the actual spatial variability of grade as measured through the variograms of the drill hole data. Simulated maps can provide a number of equiprobable images of the mineralization geometry from which a more appropriate mining model of the mineralization can be developed. Multiple simulations can also be used to assess the uncertainty existing in the current knowledge of the reserves.

Jan 1, 1990

By D Craw

Interactions between structure and lithology in the Hyde-Macraes Shear Zone controlled the style of gold mineralisation at the Macraes mine. Large volumes of rock in some mine pits have most gold disseminated in hydrothermally altered schist, rather than in quartz veins. Mineralisation was initiated in the latter stages of metamorphism. Pods of massive schist rich in quartz and feldspar are surrounded by more fissile schist consisting of interlayered micaceous and quartzofeldspathic schist. Later shears have been partly controlled by the micaceous schist, and anastomose around pods of more massive schist. Micaceous schist was replaced by pyrite and arsenopyrite, accompanied by recrystallisation of phengitic muscovite under lower greenschist facies conditions. Gold occurs in sulfides and with microcrystalline quartz formed during minor silicification. Massive schist is locally mineralised along sulfidic microshears which have phengitic muscovite largely illitised under sub-greenschist facies conditions. Mineralised massive and micaceous schists were overprinted by cataclastic shears, with addition of graphite and more sulfides. Mineralisation occurred during a transition from ductile to brittle deformation regimes as the schist was uplifted in the late Jurassic.

Jan 1, 2004

By S Holmes

Solid Energy New Zealand operates the Stockton Opencast Coal Mine, a unique deposit consisting of high quality hard coking and thermal coals. Stockton's uniqueness includes high variability of the shipment specifications, strict quality constraints, minimal stockpiling capacity in the coal transport chain and the variability of coal quality both vertically within the seam and laterally across the deposit. The process of resource proving and modelling results in a high level of understanding of the deposit to allow detailed planning to be undertaken. The use of computer aided mine planning tools is an important component of the mine planning at Stockton. Detailed planning is implemented in the field through selective mining practices and monitoring to minimise dilution and maximise recovery of the coal resource. The quality variability in the coal, the æjust in timeÆ approach of the coal transport chain and markedly varying quality specifications from shipment to shipment requires a large coal inventory and the mine to be driven by quality constraints rather than material movement capacities.

Jan 1, 2003

By P Lamberg, M Lyyr, S Heimala, J Liipo

Since the introduction of froth flotation for industrial practice, the process has long been developed and improved by making cultivated guesses or by using trial and error methods to a varying degree. Fresh possibilities have emerged after development of new surface sensitive analysing methods and in situ electrochemical methods. Having had the possibility to combine different findings between science and everyday plant practice, Outokumpu has been able to develop a catch-all procedure to manage a flotation process taking into account the specific requirements set by different minerals in a slurry. A number of these procedures are available and offered globally to clients as part of a Plant Audit service. The Outokumpu Plant Process Audit (Process ef-X) concept comprises of mineralogical determinations from process samples and plant data analysis together with electrochemical process measurements using mineral electrodes. Automatic control loop analysis can also be included. The objective is to combine the results for a basis of flotation process improvement. Since this methodology has earlier been an in-house practice, it follows that the results are also reflected in the development and design of the OutokumpuÆs processing equipment. An increasing number of ores have a very intimate fine-grained texture and it may be physically impossible to combine high grade with acceptable recovery by a flotation process alone. For such cases, combinations of different hydrometallurgical û mineral separation û pyrometallurgical processes are available. Mineral specific information and chemical expertise of flotation technology can be utilised in development of other processes, as well.

Jan 1, 2005

By Till M, McGee WA

The Hermit Islands are situated at 145¦ E 1 30'S in the Bismarck Sea approximately 200km WNW of Manus Island. They are dominated by basalt flows, one of which yielded a K/Ar isotopic date of 3.4 + 0.05Ma. All basalts examined were olivine-bearing, but one sample also contained hornblende. Although many outcrops were weathered, no evidence of pervasive hydrothermal alteration was observed on any islands and non-weathered rocks are petrographically fresh and many retain glass.

Jan 1, 1990

By M S. Powell, M P. Bueno

The commonly used SAB, SABC and run-of-mine (ROM) ball mill circuits can achieve high throughputs with good operating stability. However, these circuits consume a substantial amount of grinding media, which can have a substantial impact on the OPEX and the æcarbon footprintÆ, specifically when viewed as an æembodiedÆ energy input. On the other hand, fully autogenous (AG) circuits can operate at much lower operating costs, but with limited throughput. The control of AG mills, fed by ores with hard and soft components, can also be challenging, due to the sensitivity of the mill to the ratio of hard to soft components.In this paper, a multi-component modelling approach was used to demonstrate that the harder component should be used as grinding media, and its use should be kept to a minimum to avoid reduction in the mill throughput. There is an optimal blend of hard to soft, and any optimal blending condition is both ore-dependent and mill-specific. Establishing this blend is challenging, and consequently discourages the use of autogenous mills. The new modelling approach addresses this challenge by providing a quantitative prediction of the influence of blending soft and hard components in a mill. This prediction can then be used to establish the required blend for maintaining a stable and efficient operation in autogenous grinding mode.CITATION:Bueno, M P and Powell, M S, 2012. How to use hard ore components as grinding media, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 31-36 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

The re-development of the Mount Charlotte gold mine in Kalgoorlie was carried out piece- meal as funds became available. Optimisation of productivity to offset the high risk which is a function of an indefinite gold price, has been the principal objective of the management.

Jan 1, 1980

Facies associations in the Okiduse Volcanics, woodlark island, suggest that two major volcanic centres erupted synchronously during the Middle Miocene. These centres are referred to as the Watou Mountain Eruptive Centre and the Uvarakoi Caldera. The Watou Mountain Eruptive Centre, centred on Boganuse Mountain in the Okiduse Range, was a typical, moderate-sized composite volcano (or stratovolcano). The seq-uence is readily divisible into lava (Boganuse lava unit), breccia (Nikuben breccia unit) and epiclastic (Talpas sandstone unit) dominant facies, typical of composite volcanoes. These facies girdle Boganuse Mountain and they are interpreted to represent vent, cone forming and ring plain associat-ions, respectively. These facies indicate a reconstructed volcano of approximately 1,700m height with a basal diameter of 7km. The presence of limited exposures of intrusive associated with the vent facies (Kuike'beimmicrodiorite) suggests that the volcano is only partially dissected. The Uvarakoi Caldera is a felsic volcanic system contrasting with the mafic Watou Mountain centre.

Jan 1, 1994

By Singh RN

The Bulli Coal Seam, located in the Illawarra Coalfield of New South Wales, has a long and varied history of sudden outbursts. From available information this problem has resulted in twelve fatalities over the last one hundred and one years, with over five hundred separate outburst incidents being identified. These incidents have varied in severity and intensity from the discharge of 1 to 2 tonne of coal, with a slight increase in gas emission, to the discharge of 200 to 400 tonne of coal with some 6,000 m3 of gas being liberated and large items of mining equipment being pushed 1 to 2 metres down the roadway.Geological features associated with these outbursts can be mapped on a regional and mine by mine basis, to provide some indication or warning. Similarly changes in gas content and gas composition can also be determined on a regional and mine by mine basis. However sudden geological changes (such as a 6.5 metre seam displacement within 15 metres) variations in gas content (such as 6 m3/tonne to 15 m3/tonne) and changes in gas composition (from 95% CH4 to 90% CO2) all within one mine does make the prediction or forecasting of outburst incidents exceedingly difficult.

Jan 1, 1998