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By Campbell J

After eighteen months of discussions with employees and their trade unions, multiskilling was introduced at the Hellyer concentrator in early 1989, coinciding with the plant commissioning. Multiskilling was introduced with the Hellyer Skills Acquisition Program together with intensive training and performance assessment. Design innovations have helped to improve productivity. There have been some difficult times with personnel tending to return to the old and traditional ways of operating. In general, these have been overcome to ensure the success of multiskilling at Hellyer. The main factors making multiskilling effective have been continual training and assessment, and a competent team of shift supervisors. This has improved work standards towards the high level expected from a multiskilled approach without compromising safety standards.

Jan 1, 1991

The mining. operations of Bougainville Copper Pty Limited are located at Panguna on the Island of Bougainville which is part of the Territory of Papua and New Guinea. Mineralisation in the Panguna area was first established by C.R.A. Exploration Pty Ltd in 1964. Exploration work since then has established ore reserves estimated to be 760,000,000 tons of.0.47% copper and 0.4 dwt./ton gold. An economic feasibility study completed in July of this year has enabled a decision to be made to proceed with a major mining operation. The ore will be mined by open cut methods and will be treated in a conventional concentrator with a nominal capacity of 90,000 short tons per day. The concentrate will be pumped as a slurry through a 15 mile long pipeline to a port established on the east coast where it will be filtered and dried ready for export. Other supporting facilities for the mine include two towns, a 135 megawatt steam power station, and access roads.

Jan 1, 1970

By W Wu

The prospect of discrete element modelling (DEM) being used as an everyday design tool for transfer chutes in the iron ore mining industry is becoming more and more probable. However, much care needs to be taken to ensure accurate results are obtained. Whilst there are many publications in industry portraying the potential of DEM, there is little evidence of where it has been validated against a real set of experimental results. The purpose of this investigation was to gauge whether the incorporation of the physical properties of a specific bulk material at the DEM pre-processing stage can yield visually and numerically accurate simulations for a simple flow case. Effects such as irregular particle shapes, varying frictional properties and coefficients of restitution, all found through experimentation were investigated. Video analysis was used to compare simulations to real flow cases. It was found the most critical attributes in determining the accuracy of the simulations were particle shape and wall friction. Keeping the particle-to-wall friction factor constant was not sufficient to describe the flow accurately. But by introducing the varying effects of wall friction with consolidation stress, the correct results were simulated.

Jan 1, 2007

By C Grobler, M Recklies, G Jiang, I Taylor, M Morgan, G MacDonald, L Smith

The resource estimation of lateritic deposits, such as Aurukun, presents specific issues related to the lateral changes in thickness and elevation of the various horizontal layers (or zones) within the deposit where the x and y dimensions are orders of magnitude greater than the z dimension. The objective was to develop a three-dimensional (3D) block model that retained the vertical and lateral variation inherent in deposits of this type to allow full optimisation of the production plan without prior selection of an economic portion (enriched bauxite layers) of the profile at the resource estimation stage. The Aurukun bauxite deposit is held by Chalco Australia Pty Ltd (Chalco) and forms part of the world-class Weipa bauxite province, Cape York Peninsula, Queensland, Australia. The bauxite is predominantly pisolitic with an upper boehmite-rich zone and lower gibbsite-rich zone. The bauxite consists of both in situ and reworked domains, is overlain by a thin soil horizon and has kaolinite clay as a transitional base. A portable infrared mineral analyser (PIMA) was utilised on site, in addition to elemental assay, on each drill sample to determine the mineralogy, in particular levels of boehmite, gibbsite, kaolinite and reactive silica. As part of the scope of work, a field program was undertaken using large diameter Boart Longyear sonic drilling to acquire detailed density measurements across the deposit to allow compliance with Joint Ore Reserves Committee (JORC) reporting requirements. Interpretation of the stratigraphy was conducted on a hole by hole basis with definition of the zone layering based on stratigraphy, geochemistry and mineralogy. The zone boundaries were then modelled as 3D surfaces and used to constrain a block model. The block model estimation used the ordinary kriging method, with the estimation done in unfolded space and then refolded, therefore maintaining the zones irrespective of thickness or orientation. The unfolding process converts the real-world positions for both blocks and informing samples to a scaled position relative to the roof and floor of each zone. Analysis of the data and variography were also undertaken in unfolded space. The x and y dimensions are unchanged, but the z dimension is a relative position. The effect of the unfolding and limits on number of samples per hole is to æpushÆ the informing sample search sideways but within the stratification, rather than vertically. This honours the strong vertical zonation within the bauxite profile. The JORC Code requires that the stated resource must have æreasonable prospects for economic extractionÆ. This is a qualitative rather than quantitative definition. A number of selection criteria to define a resource roof and floor were developed in consultation with the project engineers and owners to meet these criteria. The vertical selection of material to include in the resource highlights the variation in the development (and destruction) of the bauxite profile from area to area within the deposit.

Jan 1, 2009

By Wilson AF

Gold-silver mineralization at Cracow and Ukalunda in Queensland comprise quartz-filled veins, fissures and breccia zones hosted by propylitically altered volcanics and epizonal intrusions which are strongly fractured. The terrestrial volcanic facies, structural setting, type of alteration and complex mineralogy suggest these deposits are of the epithermal type.The 180 depleted character of the wall-rocks is consistent with the involvement of meteoric waters in convective hydrothermal cells associated with the vulcanism. The Cracow quartzes have remarkably low 6180 values from -2.0 to -3.4 per mil typical. of meteoric hydrothermal systems at high latitude, consistent with the inferred position of Australia during the Permian. 6180 values for the Ukalunda quartzes exhibit a wide range from 5.1 to 14.9 per mil which reflect the mixing of magmatic and meteoric waters, and a steep geothermal gradient.Further stable isotope and geochemical studies are in progress to establish the scale and morphology of the zones of anomalous 6180 and mineralogy in the wallrocks which constitute significant exploration targets.

Jan 1, 1984

Research cruises dedicated to seafloor hydrothermal activity along the Kermadec arc first began with the Sonne-135 expedition in 1998. This was followed by the worldÆs first systematic survey for venting along an arc during the 1999 NZAPLUME I expedition. Since then, cruises dedicated to mapping plumes along the Kermadec arc include NZAPLUME II (2002), NZAPLUME III (2004) and ROVARK (2007). In addition, the manned submersible cruises SWEEP Vents (2004) and NZASRoF (2005) utilised the Shinaki 6500 and Pisces V, respectively, to sample in detail select hydrothermalsystems for mineralised samples, rocks and vent fluids. The ROVARK (2007) cruise was the first to deploy an autonomous underwater vehicle (ABE) along the arc which surveyed Brothers volcano at a far greater resolution than had been done previously by ships on the sea surface. While these expeditions have largely been led by GNS Science, together with its collaborators from National Oceanic and Atmospheric Administration, Pacific Marine Environmental Laboratory (NOAA/PMEL), significant contributions have been made by other groups from various nations, exemplifying the global interest in seafloor hydrothermal activity associated with intraoceanic arcs. This is an ASTRACT only. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By W P. Breytenbach

"The phased application of statistical process control (SPC) infers that processes are classifiable as pre-SPC (or phase zero), phase I and phase II processes, with different objectives being pursued in the different phases. Phase zero processes, defined as processes affected by assignable causes of variation, are characterised as follows: out-of-control with unknown autocorrelation structure having an unknown statistical distribution not performing consistently on target with minimum variability potentially incapable of conforming to the product specifications. The objectives of phase I SPC is to obtain estimates of the mean (µ), variance (s2), probability density function (f(X)) and the autocorrelation structure, as well as transforming the process into a phase II process (defined as a process conforming to specifications and performing on target with minimum variability). As in any other type of research or pragmatic improvement intervention, sampling is required is to achieve these objectives. The challenge of deciding a phase I sampling plan is multifarious since it has to cope with the aforementioned effects of assignable causes and provide for rigour estimates of the unknown parameters. Furthermore, deciding sampling plans in phase I invariably presents a classical catch-22 situation: appropriate sampling is required to determine the autocorrelation structure of a variable, but knowledge of the autocorrelation structure is required to formulate an appropriate sampling plan. This paper suggests, for random variables, guidelines to formulate sampling plans, and presents a methodology to estimate the inherent process parameters of process variables and an approach to identify assignable causes in phase I. CITATION:Breytenbach, W P, 2014. Rational sampling and standard deviations for random variables in phase i application of statistical process control, in Proceedings Sampling 2014, pp 141–154 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 29, 2014

By Ellson I. G

Shay Gap was created for the sincrular purpose of housing, in comfort, the workforce that would be required to mine iron ore, from leases held by Goldsworthy Mining Limited, in hill country, approximately 170 kilometres east of Port Hedland in the Pilbara region of Western Australia. To combat the and environment, the Company ultimately decided to adopt a novel planning concept for the town, which had not been attempted before in Western Australia. The special problems encountered during planning, and the reservations that were expressed during construction and early settle ment, are now part of the dim past. During the three years of occupation now achieved, there has been accumulated a story of success in the provision of an acceptable alternative to modern suburbia. Not only may this be claimed, but it can also be argued that the Shay Gap concept has been a more successful solution to a real environmental problem in our arid Pilbara region than has been seen in other similar settlements.

Jan 1, 1976

The Melanesian Outer Arc, extending from. Papua New Guinea to Fiji, developed as a result of interaction between the Australian and Pacific plates throughout the Tertiary, and the following stages are recognized. ,a, Formation of island arc tholeites above a west facing subduction zone in the Lower Tertiary. fit Emplacement of mainly calcalkaline volcanics above an east facing subduction zone in the Upper Miocene and Pliocene. ontinued east facing subduction coupled with fragmentation of the arc from the Pliocene onward. Alkaline and Mg-rich volcanism occurred in addition to continued calcalkaline activity. Tre Upper Miocene and younger volcanism is into five arc segments on the basis of geographic position and nature of the magmatism. The calcalkaline Bismarck arc extending along northern New Britain and including small islands to the west. The alkaline Tabar to Feni arc, north of New Ireland. The Solomons arc, including Bougainville and the western part of the Solomon slands. Volcanism is largely _.alcalkaline, but Mg-rich varieties occur the Solomon Islands. roe New Hebrides arc, extending from the -astern Outer Islands of the Solomons through Vanuatu. Both calcalkaline and :alkaline volcanics are representeo. alkaline and calcalkaline Fiji arc.

Jan 1, 1987

Coal slurry pumping was introduced into the U.K. in 1973. Gateside packs were prepared in areas of containment using R.O.M. coal and a special fast setting cement. The packs restricted roadway convergence and moderated spontaneous combustion risks, but costs were high and alternptives were sought. A similar system using OPC and an accelerator had limited success. Much more successful was the Aquapack process which used dilute slurries of a special OPC based cement and an accelerator based on sodium carbonate and bentonite pumped simultaneously into la fabric packbag. The Tekpak system using HAC and a much modified calcium sulphate mixture superceded Aquapack on the grounds of improved cement pumping life lower alkalinity and lower costs. A further modification of this system gave a cement with a 24 hour pumping life thus obviating flushing out pipe ranges except at the week-ends, improved packbags also increased the efficiency of the process. The hazard of spontaneous combustion can be inhibited if air supply channels across the waste can be located and plugged. Using gas samples from pack pipes to locate the heating and injecting a special grout, formulated from bentonite, sodium silicate and thixotroping agents. into the waste on the intake road has proved a successful method of controlling heatings. Mine' roadway and face cavities are being safely and successfully filled with cementitious foams produced in a novel placer machine. The foams are based on fast setting cements with specialised foaming agents. Up to 13 cu. metres per hour of fast setting thixotropic foams can be produced and their use is now widespread throughout U.K. coal mines.

Jan 1, 1986

By M Byrne, P Newman, M Lindqvist

SomincorÆs Neves Corvo Mine, one of the largest copper producers in Europe, is currently constructing a paste backfill plant in order to replace cemented rockfill in its bench and fill stopes and possibly replace hydraulic sandfill in the drift and fill stopes. A 250 m flow loop was constructed at the mine and the flow properties of various paste blends were investigated. Cycloned tailings and total tailings were both pumped successfully as pastes and were also combined with waste rock for additional testing. The pressure losses in 102 mm and 154 mm diameter pipeline were recorded at flowrates up to 60 m3/hr and are presented at slumps from 120 mm to 250 mm. The data showed the sensitivity of paste mixtures to slight changes in consistency, confirming the need for accurate control during paste production and distribution. The flow results clearly showed the different paste behaviour between cycloned and total tailings pastes and the change in properties at low and high slumps. In addition to pressure loss data, strength testing was done on 38 mm and 82 mm diameter samples. Further strength testing is ongoing at the mine using fly ash as a supplement to cement, reducing the overall binder cost. Preliminary engineering for the underground distribution system is briefly discussed, with reference to the siting of the plant. The Neves Corvo Mine is particularly shallow and alternative methods to pumping were sought in order to ensure sufficient hydraulic head for underground distribution. The comparison of options had to take into account the capital and operating costs, the operation of the plant and the impact on the future expansion of paste fill utilisation at Neves Corvo.

Jan 1, 1998

Callie underground gold mine is part of the Newmont Tanami Operations, and is now the primary provider of ore to the Granites processing Mill. The Callie underground mine has produced in excess of 7.6 million tonnes (Mtpa) of ore, since production began in 1998, with a current production rate of 1.9 Mtpa. Callie underground uses sublevel open stoping with extraction through a combination of primary and secondary stopes. The primary stope filling strategy utilises cement aggregate fill (CAF) to allow full recovery of secondary stopes. The Callie backfill operation has had a continuous testing program in place during this time, which has resulted in a great deal of information available for post fill analysis. All CAF placement into primary stopes for Callie has been via surface boreholes and this has given Callie mine an understanding of some of the issues related to borehole design, type of linings to use depending on angle, depth and quantity of fill into stopes. Finally backfill barricades at Callie have undergone a number of changes during the time to optimise the design based on whether CAF or sand fill is used. This paper discusses the CAF backfill practices and testing methods used for backfilling operations at Callie.

Jan 1, 2005

By Yu A. B

An experimental study of the packing of a coal heap has been carried out. The bulk density of a coal heap is considered as a function of a number of variables, viz flow rate, conveyor belt speed, the height of the disengagement point of the conveyor belt, coal particle density, moisture content, the size of the heap and coal particle size distribution. The effects of the dimensionless numbers resulting from dimensional analysis on the packing density of a coal heap have been experimentally examined and analysed. Based on the experimental results, equations have been formulated for the estimation of the bulk density of a coal stockpile. The validity of these equations are checked by comparing the predictions with measurements of real industrial Stockpiles.

Jan 1, 1991

By LaBrooy SR

A number of gold processing plants in Western Australia have nickel in their ores, leading to significant levels of nickel on their loaded carbon. The presence of nickel during leaching, adsorption and elution'may have detrimental effects on cyanide consumption, carbon inventory requirements, stripping costs, electrowinning efficiencies and may contaminate the gold bullion.This paper discusses the competitive adsorption of gold and nickel cyanides onto activated carbon and investigates changes in solution parameters that may improve gold adsorption and/or inhibit nickel adsorotion.

Jan 1, 1997

By Weller KR, Restarick CJ, Stewart PSB

Following a detailed assessment of concen trator performance at Broken Hill South Limited which was reported in a previous paper, the fine grinding section was changed from a parallel arrangement of the two grinding circuits to a series arrangement, and the concentrator per- formance re-assessed. The change to series grinding had virtually no effect on the actual or potential capacity of the circuit to make a final product with 80% passing 100 mesh. However, the fresh flotation feed contained significantly less +150 mesh lead and +65 mesh zinc (material which was shown to float poorly), without an increase in the quantity of poor-floating ultra-fine lead and zinc. From the size-by-size flotation recovery data, it was shown that overall recoveries of both lead and zinc were approximately 1% higher than they would have been without this change in size distribution and it was concluded that this was a direct result of the change in grind- ing procedure.

Jan 1, 1972

By BLAKE DAWSON WALDRON

I must acknowledge my strategic adviser, Mr Lance Grimstone, who contributed to the development of this paper, and collated the text and figures.

Jan 1, 1994

As mining and extraction processes improve and lower grade ores become economic, mining for most ores have extended to depths beneath the zone of weathering oxidation created over geological history. These deeper openings expose sulphidic formations and reduced mineral species as either primary ore or simply as accessory or gangue minerals in the country rock. This is not new, underground mining for primary base metal and gold have long been familiar with these problems, as have coal and uranium miners. The change is simply that the number of mines exposing sulphidic waste rocks, tailings to the atmosphere and/or leaving behind dewatered sulphidic rock surrounding the mine void has increased the number of sites from where acid mine drainage (AMD) may emanate with consequential problems for the hydrological environment including downstream catchments (Miller et al, 1996). The principles of ecologically sustainable development (Brundtland, 1987) have been more or less ratified by all the developed nations of the world and this has led, amongst other things, to an expansion unprecedented in the research and documentation of means for achieving long-term environmentally acceptable stabilisation of solid wastes of all sorts. These have revealed that AMD problems can be minimised and even reversed in many cases by the integration or co-disposal of biodegradable organic wastes with oxidising sulphidic wastes (Elliott et al, 1996). This paper considers how this might be achieved at mine sites in Australia and the results encountered at some relevant sites.

Jan 1, 1997

By Sheer T. J, Van Rensburg J P

The primary objective of this research was to address the demands imposed on self- contained self-rescuer (SCSR) performance dur- ing simulated escapes. The results clearly indicate that SCSR performance, apart from the inherent technological features, is a function primarily of the physical and anthro- pometric features of the wearer, and of the particular nature of the escape route. These factors consequently play a major role in the planning of any escape strategy, which may vary from mine to mine. It is therefore concluded that each mine would have to formulate its own escape strategy which in turn would depend on the choice of SCSR, and the particular escape Route.

Jan 1, 1988

Traditional methods for the production of transition metals from their ores usually include the electric arc smelting of the ore or concentrate to produce a ferroalloy. This is subsequently refined to produce either a ferroalloy or to produce the metal or metallic carbide. Recent trends in the treatment of iron ores have seen the development of many processes for solid state carbothermic reduction followed by melting of the prereduced iron to produce steel and similar types of processes are under consideration for the production of ferroalloys. There are clear potential savings in energy and control of emissions from such processes. This paper discusses some research which is currently underway at La Trobe University into the solid state carbothermic reduction of chromium and tungsten ores to produce the metallic ferroalloy or the carbide for subsequent further processing. The kinetics of the carbothermic reduction of both chromite and scheelite were found to be dominated by gaseous CO rather than by direct carbon reduction. However the diffusion of carbon into the ore is certainly an important feature of the process. The production of tungsten carbide from the metal is the slow step in tungsten reduction. The development of phases during reduction were studied using a scanning electron microscope and an electron probe and knowledge of the phases produced allows analysis of the reduction process.

Jan 1, 1997

This monograph presents a unified theory of adsorption and desorption of aurocyanide on activated carbon. This theory has proved useful for CIP/CIL carbon adsorption and Zadra and AARL elution process and equipment design; in accounting for the effects of various water qualities and process temperatures; and in the development of reagents to improve these processes. The theory presented is based on rigorous fundamentals : Classical Eyring theory links initial first order kinetics with Langmuir isotherm equilibria, and this isotherm is demonstrated for the first time to be a consequence of the activated complex postulate of Eyring theory. Simple extension to Freundlich conditions at high solution tenors is possible, but not presented. Supporting entropy data determined by the author includes practically all the pioneering CIP plants built in South Africa and Australia in the early 1980s.

Jan 1, 1991