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The Argyle AK1 Pit has been operating and producing over 25 per cent of the worldÆs diamonds by volume for over 20 years. The mining boom in Western Australia is creating upward cost pressures to ArgyleÆs mining operation while the price received for its product remains flat in comparison to many other Western Australian commodities. This incongruity, which when combined with other circumstances such as the pit being close to the end of its mine life, a decline in head grades and a tightening in operational constraints caused by the pitÆs maturity, is causing the leadership team at the mine to utilise innovative strategies in order to ensure that the open pit continues to perform economically until its final closure in late 2010. The strategies that will be discussed in this paper are step change business improvement methods, localisation of the workforce, employment of Aboriginal people and the use of a clear and concise consultation process in order to provide certainty to a workforce working in a pit during boom times where pit closure is imminent.

Jan 1, 2007

By R J. Nicholson, J M. F Clout

As part of an overall strategy to make significant new technological advances for the sustainability of the mineral processing and related process industries CSIRO Minerals has developed a new dry separation device. It represents a technology breakthrough and has the potential to radically change the way in which dry particle size classification is achieved in the minerals industry. Conventional dry separation techniques have limited applications and often suffer from low productivity, high operating costs, low separation efficiency, the need for dust control and a lack of flexibility. In the absence of efficient dry techniques, wet processing is often used. The use of wet processing either requires the introduction of water into a separation process, which causes environmental concerns through the need for water supply and tailings dams or the use of æunfriendlyÆ chemicals for dense media separations that have considerable impact on handling and disposal. Wet processing also increases operating costs due to plant instability, materials handling, thickening, filtration and product drying. The new CSIRO technology exploits a combination of natural and applied forces to achieve specific particle motions that produce size separation. In doing so, many of the traditional shortcomings of dry separation have been overcome. The CSIRO Dry Particle Size Separator is ideally suited for dry size separation applications within the size range 1 mm to 30 ¦mfor moderate moisture levels (2 per cent), have low unit throughput, produce a fixed cut size and are therefore impractical where very high unit capacity and low operating costs are required. This paper presents a review of dry separation devices together with details of the new Dry Particle Size Separator and typical results for a number of materials, including iron ore and quarry dust.

Jan 1, 2002

By Hindmarsh G

The colliery is owned by the BHP Collieries Proprietary Ltd., the principal shareholders being the Broken Hill Pty. Company Ltd. and Hebburn Limited.It is situated due west of Newcastle and 6 south-east of Cessnock, N.S.W., and is conneeted by 36 miles of railway to the port of Neweastle. Of this mileage, 3 miles are owned by the Company, 3 by Hebburn Limited, 9 by the South Maitland Railways Ltd., and 21miles by the Government Railways.The seam worked is known as the Main Greta Seam of the Greta Coal Measures and is on the southern slope of the Lochinvar anticline.At the shaft, the seam is 1190 ft. below the surface, and the section of the coal measures is:-Upper or Main Seam, . 24 ft. 0 in.Conglomerate and shale 70 ft. 0 in.'Middle Seam 8 in.Conglomerate 25 ft. 0 in,Bottom Seam 1 ft. 2 in.These lie between two marine measures, and are the lower coal series of the permo-carboniferous period.Only the upper seam is workable in this area, the lower seams being too thin for eompetitive working. The section of the workable seam at the shafts is as shown on Fig. 1.Unfortunately, only the lower 12 ft. 5 in. of the seam is saleable.

Jan 1, 1935

The global economic, political, sociological, and technical environment has become extremely volatile and unpredictable. Price and demand patterns for fuel and non-fuel minerals have become highly variable. Increasingly militant environmental movements now have a material effect on the price, cost and availability of energy sources and indirectly also on non-fuel minerals.The pace of political change in the U.S.S.R., Eastern Europe, and China has accelerated. Western Europe, Japan, and the U.S. are reacting to these changes with varying degrees of confidence or timidity.Technical and economic developments continue to have a substantial effect on the fortunes of the mineral industries. However, they are increasingly influenced by social and political factors. Supply, demand, and trade patterns in the Pacific Rim Region will continue to be influenced by developments in other regions, such as southern Africa

Jan 1, 1990

By C F. Prins, C LantuTjoul

Mineralisation in alluvial diamond or vein gold deposits is often hosted in trapping mechanisms. For instance, diamonds are nested in bedrock depressions such as gullies and potholes which were carved out by the sea long before the diamond deposition took place. Similarly, gold mineralisation can precipitate in the necks of a boudinage structure. In such deposits, the spatial distribution of the mineralisation is governed by the mutual arrangement of the trapsites and by the grade variations within each trapsite. Reliable estimates can be obtained only if they rest on a proper knowledge of both degrees of variability. This creates a challenging sampling problem, as during the exploration phase it is important to have a good global mean estimate to enable decision making towards the future. A similar problem occurs for local estimates at a later stage of development. To understand and manage the sampling for global means, specific sampling procedures are required based on an appropriate choice of sample support size and spacing. Estimates from such sampling campaigns should be unbiased, and the less variability they display, the better the sampling parameters. The performance and impact of sampling parameters are tested and compared on different simulated deposits.

Jan 1, 2005

By Orid A

A fast, non-contact technique for measuring sizes of rock fragments on a conveyor belt is presented. An image processing technique called active stereopsis is used which makes use of a light stripe projected on to the surface of the fragments on the conveyor belt. A CCD TV camera is used to capture the shape of the distorted light stripe. the video image of this shape is then processed by a computer program so that the 3D profile of the surface can be obtained by triangulation. The sizes of the rock fragments are then calculated from this profile. The speed of the technique is improved by calibrating the light stripe system before measurement begins so that the profile of the fragment surface can then be measured using simple geometry. The technique is fast and highly parallel so that it is able to operate in real time.

Jan 1, 1990

A cry that is often heard from front-line employees, particularly as a mine grows or circumstances change is "We used to be one big team but now they have set up teams for different functions - we don't know what's going on and we don't share resources any more. We used to just get in and do what had to be done, now we can't.". It usually occurs after management decides that, with the increasing mine complexity, functions and accountabilities of a manageable size need to be identified and defined for individuals and teams to facilitate optimum performance. However, as the statement indicates, these changes have often not delivered all the intended benefits. This paper will explore the reasons why the full benefits have not been realised and will identify actions which can be taken to improve the likelihood of optimal outcomes.

Jan 1, 1998

Mid-ocean ridges host approximately 65 per cent of about 100 known sites of high-temperature venting and polymetallic sulfide deposits; most of them are located at the East Pacific Rise (EPR), while more diverse mineralisation styles occur at the Mid-Atlantic Rise (MAR). Seafloor hydrothermal activity at the EPR are related to MORB while different substrates, including MORB and ultramafic intrusive rocks, are associated with æblack smokersÆ at the MAR. Depth of hydrothermal activity ranges from 0.7 to 4.3 km. High-temperature vents precipitating Cu-Fe sulfides (chalcopyrite and isocubanite, rare bornite), pyrrhotite, pyrite (¦ marcasite), and sphalerite, and low-temperature edifices precipitating marcasite (with pyrite), sphalerite, barite, andsubordinate chalcopyrite (pyrrhotite and isocubanite are absent) occur in both environments. There are considerable differences in Fe, Zn, Cu, Ag, Au and trace element contents in ores and in theFeS contents in Zn-sulfides in these deposits. Acomparison with anhydrite and sulfide minerals precipitating from modern black smoker fluids sulfide reveals many similarities but also some important differences. Fluids with salinity values above and below that of seawater at 400¦C down to 130 - 170¦C deposited sulfide minerals. Mantle-derived He prevails in fluids trapped by sulfides in EPR 9¦N and 21¦N hydrothermal systems. Hydrothermal fluids in MAR and back-arc systems are richer in radiogenic 4He. The sulfur isotope composition varies in the different hydrothermal fields and within zones of a chimney. EPR sulfides display narrower range of d34S values, while MAR and back-arc sulfides can bedepleted and enriched in the heavier d34S isotope. The most important finding is that fluid temperature, salinity, R/Ra ratios and d34S values ranged more significantly in the polymetallic sulfide deposits than when measured directly on venting fluids. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By Bhattacharyya A. K

In this paper, the current methods for predicting surface subsidence due to underground coal mining are evaluated first. A single index, called a strata parameter (P), is then proposed to describe the overall character of the undermined strata in the context of surface subsidence. Based on the strata parameter, a method for predicting the maximum surface subsidence for various panel width (w)/depth (h) ratios is presented, which has been tested against specific empirical curves or data from several coalfields in different countries. From the data relating to several coalfields, a linear relationship between the reported average angle of draw and the strata parameter has been established. It has also been found that the strata parameter can be used for studying the locations of the inflection points and the shapes of transverse subsidence profiles.

Jan 1, 1995

An image analysis system has been built which automatically digitizes camera input of rock fragments, analyses the digitised data to determine the sizes and shapes of the rock fragments, and outputs the analysed data to a printer in the form of a histogram or a scatter chart. The high speed of such a system allows for direct collection of data from material thrown into the air by blasting, material travelling on a conveyor belt, and material free-falling on to a stock-pile or into or out of a rock-crusher. Data on the blasted, un-crushed material provides information on changes in the lithology and structure of the rock face as it is quarried or mined: flatter fragments may represent approach to a brittle, unstable shear zone, or a change from sandstone to shale; so that the informa- tion reflects the effect on the sizes and shapes of the fragments by the blasting process and/or by the rock structure. The size and shape distributions of rock fragments produced during blasting and during processing may now be continuously monitored. Such detailed analysis of the results of fragmentation is labour-intensive and expensive when the size and shape distributions are obtained manually, but is cheap and efficient when using this image analysis system. Such a system will enable the results of blasting, quarrying, mining and crushing to be cheaply analysed and correlated with current and changing indus- trial practice so leading the way to increased productivity.

Jan 1, 1988

A case study of a landslide, which threatened vital infrastructure essential for the continuous operation of the Ok Tedi copper mine is presented. The paper presents a detailed description of the land- slide, outlines the assets at risk, and how the issue was addressed. This included the consideration of remedial options and the im- plementation of the most economically sound and geotechnically feasible remedial design which was completed within budget and on schedule. The paper is intended to highlight the responsibility of a mine based Geotechnical Engineering section in providing essential geotechnical investigations, design and professional advice on addressing stability issues in the infrastructure region.

Jan 1, 1997

By P Mavros, K A. Matis, N K. Lazaridis

A large number of techniques are in use today to limit membrane fouling, among them certainly is air bubbling (which constitutes the transport medium in flotation) as applied in wastewater treatment; meanwhile, dispersed-air flotation is suitable as a pretreatment stage for microfiltration. The invented and investigated hybrid cell combines the advantages of both flotation and membrane separation, while overcoming their limitations, producing clean water from industrial wastewater. Metals recovery from dilute aqueous solutions is a promising application of this innovative hybrid process of flotation and microfiltration, further to solid/liquid separation. In this study, ceramic flat-sheet membrane modules were inserted inside a typical flotation cell in the laboratory tests, using multichannel geometry, combining flotation with microfiltration by submerged membranes; the latter requiring periodic backflushing. The specific objective was to apply this process for the efficient separation of effluents containing metal cations (here, zinc). The main examined parameters were: the initial metal concentration, flotation surfactant applied and air flowrate. The successful contribution of precipitate flotation was highlighted, while the observed metal removals were of the order of ~100 per cent.

Jan 1, 2005

By P T. Hick, T J. Cudahy, M S. Caccetta

Dust derived from mining and handling of ore has been identified as a major concern for the mining industry in Australia and may be critical to the future viability of some resource industries (CSIRO, 1999). Operational techniques to derive accurate measurements of anthropogenic dust on vegetation and infrastructure are necessary for the long-term management and monitoring of the environment surrounding mining operations. Airborne hyperspectral VNIR-SWIR systems can potentially provide these monitoring data. This paper outlines a method developed for deriving quantitative measurements of dust quantity on mangroves using remotely-sensed airborne hyperspectral data. The results show that it is possible to detect and quantitatively map iron oxide dust distribution using properly calibrated airborne visible to short wave infrared (VNIR-SWIR) data.

Jan 1, 2002

While convergence of plates at a subduction zone produces shortening at the toe of the overriding plate, this deformation is localized to the frontal 100 km or so of the plate. There is increasing evidence that the state of strain in back-arcs, volcanic arcs, and possibly the entire forearc is extensional. The most likely cause of this extension is rollback of the subducting plate and trenchward advance of the overriding plate. Arcs are thermally weakened, and are activated repeatedly through time. The primary expression of the extensional state of strain is spreading of the weak arc material, either by splitting the arc or by back-arc spreading behind it. This study presents evidence for extension of volcanic arcs from an analysis of the moment tensors of shallow earthquakes (

Jan 1, 1990

The liquid products of low-temperature carbonisation of coal are of variable composition, very much influenced by the rank and type of coal, and process parameters. In general the tar contains a high proportion of phenols and a low proportion of bases. The neutral oil is more analogous to a thermally cracked petroleum oil than to a high temperature tar. Present practice and possible future trends in the production of chemicals and liquid fuels from low temperature tar are reviewed in the light of recent work on the detailed composition of the tar The phenols and aromatics will probably continue to be of most value, with the bases a useful source of spec- ialty products. However the high aliphatic content of the neutral oil (particularly 1-olefins and n-paraffins) is bound to receive more attention for chemicals as well as for liquid Fuels.

Jan 1, 1969

By King CJ

The C.S.A. concentrator of Cobar Mines Proprietary Limited was expanded in 1974 to treat 80 000 tonnes of copper-lead-zinc ore per four week period. Jaw crusher product is fed to two par- allel primary autogenous mills followed by a secondary ball mill. Each mill operates in closed circuit with cyclones. Improved control of grinding rate and product sizing has been obtained from this circuit compared with the system of two parallel single stage autogenous mills. The main operational variables are des- Cribed.

Jan 1, 1978

By D Nourry

Optimising the blast is a major issue in the blasting business. It generally means acting on the blasting pattern (drilling, charging, detonating) in order to get a given æresultÆ. This result may either be related to economic reasons, such as the fragmentation influencing productivity, or technical reasons, for example vibrations and projections. Within the frame of the EEC funded Brite-Euram project entitled æBlast-ControlÆ, involving academic research and applied expertise, a general methodology was developed to approach such a problem and currently applied to the industrial partners of the project and final end-users of the generated results. These partners are the limestone ALZO quarry of the CALCINOR group in the north of Spain and the dolomite DMD (Dolomies-de-Marche-les-Dames) quarry of the LHOIST group in the east of Belgium. A first part of the project, over 18 months, was dedicated to establishing a clear relationship between productivity of operations from drilling to primary crushing and the fragmentation resulting from the blast. Extensive monitoring of blasting, production performance and fragmentation data was carried out and automatically collected into a database on both quarries. As expected, it appeared that excessive amounts of fines or boulders were substantially reducing productivity and thus profitability of the operation. Furthermore, an æoptimalÆ fragmentation was assessed for the quarries to run at the best (high throughput, low cost). The second and last part, for the remaining 18 months, was then dedicated to adapting the blasting practice in order to orientate the fragmentation towards a æbetterÆ one. A very common problem normally addressed by any consultant. Nevertheless, the target was not limited to solving the problem for these two quarries, but also to develop a generic method to address this blasting adaptation process and to implement it into a computerised tool. At this stage, it is then obvious that portability of the method and the system are major qualities to be looked for. This paper is aimed to present how this method was developed, how the system was implemented and how it was finally used.

Jan 1, 2001

By Peng S. S

Measurement of pressure distribution under the base plate of the Hemscheidt 2-leg 800-ton shield was performed underground for two shifts using 12 pressure cells installed in two rows, one each under each split base plate. Pressure distribution was uneven depending on contact condition. In general the highest base pressure occurred at 1/3 of the base plate contact length from the rear edge. The resultant was near vertical, and the pressure under the tail side split base plate was always higher than the head side. For comparison, pressure distribution on the canopy and under the base plate was also measured under controlled conditions at the USBM's Mine Simulator Testing Facilities in Pittsburgh, PA. A total of 45 tests were conducted under several simulated contact conditions. The results showed that the actual contact area is highly dependent on the compliance of the immediate roof and floor due to the sloped canopy tip and a base lifting device under the base tip. The loading distribution tends to change in magnitude and profile as the leg pressure increases. The base lifting device exaggerates the high toe loading on the base plate characteristics of this type of shield support.

Jan 1, 1992

North Flinders Mines Limited (N.F.M.) is an Australian-owned mineral exploration and mining company based in South Australia. In the 1970's it researched the prospectiveness of the Tanami (central western region of the N.T.) for the identification of possible economic gold deposits. Having outlined the potential for such a deposit at The Granites (550 km. N.W. of Alice Springs), it marked out and in 1975 applied for the grant of eleven gold mining leases (G.M.L.'s) under the provisions of the then Mining Ordinance. This application was deferred by the Commonwealth Government during the time of the Aboriginal Land Rights Commission (Woodward), subsequent enactment of legislation and land claims. In 1980, the Walpiri and Kartangarurra-Kurintji land claim encompassing the G.M.L.'s, became Aboriginal land. It therefore became necessary for N.F.M. to negotiate a mining agreement with the Central Land Council (C.L.C.) represent- ing the Traditional Owners, before the G.M.L.'s could be granted. In August 1983, the C.L.C. and N.F.M. concluded an agreement to enable the grant of mining interests necessary for the devel- opment of The Granites Gold Project. In several ways this agreement is unique in That:

Jan 1, 1984

Quite apart from economic considerations, the following performance parameters must be considered when selecting an explosive for a particular blasting operation. 1. total energy yield/kg, and more particularly, strain energy/kg and bubble energy/kg of charge 2. charge weight/m of blasthole 3. sensitivity of the charge 4. water resistance of the charge The effective division of an explosive's total energy into strain energy (SE) and bubble energy (BE) is explained as is the influence of each energy component on blast results. Because some rocks require a high strain energy for effective breakage, while others are most satisfactorily fragmented by bubble energy, values of SE and BE are more meaningful than those of total energy. Unfortunately, our extensive knowledge of the effects of certain variables on total energy has not yet been completely supplanted by the influence of these variables on SE and BE values. Relative SE/kg and BE/kg values are presented for a range of explosives. The 'charge density of ammonium nitrate/ fuel oil (ANFO)-type explosives is essentially constant throughout the length of the charge; because of their compressibility, slurry

Jan 1, 1974