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By Moffatt G

Approval to operate Longwall No. 7 at Appin Colliery in 1979 was granted pursuant not only to the usual statutory provisions, but also that an adequate means of drainage of methane gas be incorporated. A methane drainage plant was subsequently designed and constructed some two km from the pit top at the site of the Colliery main upcast and down cast shafts. Modern plants of this nature are completely automated using programmable controllers and computers to provide control and management reporting functions. Complex mechanical systems are installed to extract the gas and in handling and storage processes. Gas utilisation plants exist which can generate power from methane. These plants are further enhanced by harnessing waste heat produced in the generation process. The installation, automation control and monitoring of these plants incorporates many facets of engineering from high voltage power supply and computer technology to complex gas handling procedures used in gas compression storage.and generation of electric power.

Jan 1, 1982

By K Haroon, J D. Speed, S P. Wood

Online analysis of continuous and batch processes has seen a dramatic increase in recent years, with examples ranging from petrochemicals to pharmaceuticals, to industrial biotechnology and food and drink. The particularly challenging environment of alumina processing has meant that instrumentation needs specific features and characteristics to be truly suitable, features such as: robustness, resistance to caustic conditions both in the analyte and the ambient environment, and reliability for long-term continuous use. Here we present the development of a novel FTIR spectrometer that achieves these requirements through the use of a static optics arrangement of mirrors, and stable diamond-tipped light-pipe probe. Firstly we give a very brief explanation of spectroscopic analysis, and the difference between FTIR and other infrared methodologies. Next we outline the novel arrangement of mirrors required to produce an interferogram without moving mirrors, and compare the benefits and drawbacks of this approach instead of conventional designs. We then share the results of laboratory analysis of synthetic Bayer liquors, with detection limits for aluminium hydroxide, sodium hydroxide, sodium carbonate and various sodium salts of organic acids. We then share the results of analysis on production samples, both in idealised laboratory conditions and then online in the process itself. Lastly we present work on in situ ultrasonic descaling solutions to avoid scale build-up and provide continuous cleaning of the probe – preventing the need for probe removal and manual cleaning.

Aug 24, 2022

By G D. Richmond, J C. Chomley

Copper has been mined intermittently at Gunpowder, north of Mount Isa, since 1927. Most ventures have had some initial success but fluctuating copper prices, the small-scale of the operations and the remoteness of the site led to closures or sale. Processing routes have included direct sale of high grade ore, flotation of oxide and sulphide concentrate, and copper cement production from mine solutions. Copper cathode has been produced by heap and in-place leaching coupled with solvent extraction and electrowinning (SX/EW). Aberfoyle Limited recently purchased the Gunpowder operation and is expanding operations. An innovative high recovery tank leaching process, including a low temperature, low pressure autoclave, has been adopted. Copper cathode will be produced from an expanded solvent extraction/electrowinning plant at approximately 45 000 tonnes per year. The combination of expanded throughput and high metal recoveries will make Gunpowder a cost competitive producer.

Jan 1, 1998

The economic viability of many Southern African massive mining operations is threatened by excessive dilution. In many operations currently in progress, some stopes are experiencing as much as 115 per cent waste ingress reporting to drawpoints. This paper examines the magnitude, causes and types of dilution and presents a set of general principles for the control of dilution in massive stoping operations.

Jan 1, 2000

By X Yang, T Zhang, Z Li, Z Yan, M A. Williams, S Qin, P Wilson

Continuous development of complex new steel grades to meet the ever-increasing demand of high performance causes recurrent issues in steel continuous casting such as surface quality defects (eg cracks, depressions, deep oscillation marks) and productivity challenges (eg faster casting, near-net shape casting). Continuous casting of steel is a highly successful metallurgical process. Much of this success can be attributed to the performance of the casting powder that is added to the top of the mould, creates a liquid slag pool as it is heated, and forms a slag film between the watercooled copper mould and steel shell during its passage down the mould. Mould powder selection is a compromise between the conflicting requirements of heat transfer and lubrication. In an EU RFCS (Research Fund for Coal and Steel)-funded project, various techniques are developed to offer the opportunity to adapt the slag film to meet the conflicting needs in different parts of the mould such that mild cooling can be generated in the meniscus, mid-broad face or corner areas whilst maintaining lubrication and offering higher cooling rates in other areas of mould. This has significant potential to address the industrial issues in product quality and productivity of continuous casting. This paper reports, as part of the EU RFCS project, the determination of crystallinity and porosity in slag films for casting challenging and innovative steel grades using new methods. In comparison with the methods such as X-ray powder diffraction (XRD) analysis and optical microscopy / scanning electron microscopy (OM/SEM) analysis that are currently adopted by the industries, EBSD (electron backscatter diffraction) has been employed to determine the crystallinity of the slag films taken from industry casters. X-ray computed tomography (XCT) plus 3D image reconstruction has been used to determine the slag film % porosity with pore volume, pore size distribution, and pore location, which can be linked with the performance of the slag films during casting different steel grades.

Jun 19, 2024

By P Hodkiewicz, K Noormohamed

Gold deposits in the Chirano district in south-west Ghana are hosted in a variety of structural settings along the Chirano shear zone (CSZ), in Paleoproterozoic rocks of the Sefwi-Bibiani belt. Most gold mineralisation occurs in strongly sheared and hydrothermally altered Birimian mafic igneous rocks and tonalite intrusions within the CSZ. A recent program of open pit structural mapping, core logging, and three-dimensional modelling helped to define deposit-scale structural controls on gold mineralisation. These include strain domains, shear zone flexures, shear zone intersections and vein arrays associated with host-rock competency contrasts. Interestingly, the plunge of higher-grade shoots in some deposits appears to be associated with the intersection of the CSZ and broadly folded Tarkwaian sedimentary rocks, which are not significant gold hosts in the Chirano district. This paper presents the results of 3D modelling that were used to define structural controls on mineralisation in several open pits and one underground mine along a 9 km length of the CSZ. LeapfrogÖ software was particularly useful because it highlighted the orientations of structural features that focused hydrothermal fluid flow during alteration and mineralisation. The improved understanding of structural controls provided two main benefits: near-mine exploration drill targets and better definition of structural domains for resource estimation.

Jan 1, 2009

By R Blin, R Walde, R Belli, D Inaudi

A fiber optic distributed sensing system allows the monitoring of parameters useful to determine the short- and long-term behaviour of the structure in response to the external actions, including, eg seismic activities as well as long-term phenomena such as seepage, tunneling, sinkholes, and other geo-structural movements. Monitoring of large retaining structures with such a system provides direct strain/deformation and temperature measurements on the broad interior area with an arrangement of several sensing cable lines, enabling early detection, localisation and sizing of subsurface damages. Measurements are provided every meter along the entire sensing cable, this is particularly important in such cases where the location of defects and damages cannot be predicted. Fiber optic distributed sensing cables are generally available for retrofit installation inside the dam structure using trenches on the downstream face or laid during construction below the geomembrane liner within the bedding sand layer. Mapping the cable route enables exact correlation between a linear coordinate on the cable length and a position in the dam. Cable installation is envisaged to be carried out during further raising of the embankment; additional cable sections are plugged to the previously installed cables and measured with the existing measurement system, requiring only an update of the mapping. The measurement system is placed remotely from the sensing area since a section of sensing cable can be used to link to the sensing area at the storage facility several kilometers away. The system is available for on-line, 24/7 real-time operational data management. Such fiber optic distributed sensing systems allow storage facilities to be monitored with long, accurate, continuous and precise data for geotechnical diagnostic purposes. This contribution will introduce the principles, benefits, and limitations of this technology.

Jul 1, 2021

By U Rehm

The biggest hard rock double-shield tunnel boring machine (TBM) in the world, with a diameter of 12.4 m, is currently excavating the North-South Bypass, which includes a crossing under the Brisbane River, Brisbane, Australia, to relieve the often congested road traffic in the city centre. Ten years ago a 10.7 m Mixshield giant helped to handle the Olympic Games in Sydney linking the airport with the city centre for an improved transportation of fascinated visitors. In Shanghai, currently the biggest TBM in the world with 15.43 m diameter presents excellent performance rates; and in Paris a convertible Mixshield could be quickly changed from earth pressure balanced (EPB) to slurry type in order to handle the very heterogeneous ground conditions. In Madrid a 15.2 m EPB giant finished its tunnel job four months ahead of schedule. Large-scale TBMs have proved their economic and innovative potential to create the current and future underground architecture of mega-cities. TBM technology has made further large innovative steps in the last decade. State-of-the-art is a TBM for very heterogeneous ground conditions comprising hard and soft rock with additional high groundwater pressure. The machine concept is adapted to the various ground conditions and allows for a quick and flexible application. Ground treatment by means of additives developed to a helpful tool in this connection. To meet the special challenges of urban tunnel projects of nowadays it is of very high importance, beside applying highest developed technology of TBM, to have a comprehensive technical support during the project phase and to develop positive relationships between all participants of the project which last longer than only for one project.

Jan 1, 2008

By Rynn J. M W, Paynter A

Recent studies by the authors have concerned themselves with assessing the earthquake risk to north-eastern Australia, based on available historical earthquake data for the area. There have been several significant earthquakes (Richter local magnitudes of the order of 6) concentrated in the Wide Bay - Burnett region in central eastern Queensland, although none of these has occurred close to a significant centre of population or development. Using derived average acceleration attenuation relations and world-wide data on earthquake-induced damage as a basis, conditions under which earthquake-induced liquefaction may occur have been investigated and presented in graphical form. Historical earthquake data for north-eastern Australia have been overlain on this graphical presentation and it has been demonstrated that the Wide Bay - Burnett region, in particular, may in the past have been on the verge of earthquake-induced liquefaction, where ground conditions are susceptible. When this is viewed in the context of the rapid growth in population and development in this area over recent years, the risk can no longer be ignored with impunity.

Jan 1, 1990

By C Bonini, A Markham, P Whittle, B Pearson

"Mine-derived sedimentation in rivers can have significant impacts on the processes and features of the receiving environment and impact on communities reliant on this environment. However, identifying and quantifying the contribution of mine-derived sediment to the receiving environment can be complex. This is particularly the case in remote environments and where little/no baseline assessments have been undertaken. One approach that can be used involves sediment fingerprinting, whereby a unique tracer is identified within the mine-derived sediment to discriminate between mine- and non-mine derived sediment sources downstream. The technique typically involves sampling of sediment at upstream, control and impact sites and sites within the mine deposit. Laboratory analyses are run on all the samples to determine whether the chemical signature (eg presence/concentration of specific metals) differs between each group of samples. In complex environments where the mine-derived signature may be difficult to detect from a basic review of the data, or where sampling constraints may limit the number of samples for analyses, statistical methods can be used to help identify sediment groups. This paper provides a mine case study to show how such an assessment can be undertaken despite the logistical challenges faced while working in remote environments.CITATION:Pearson, B, Markham, A, Bonini, C and Whittle, P, 2013. Fingerprinting and signatures - tracing mine impacts in complex aquatic systems, in Proceedings Water in Mining 2013, pp 287-292 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 26, 2013

FOR some time it has been recognised by the Metallurgical Staff that the presence of pyrite in the ore was adversely affecting the grades of the flotation concentrates.Following experimental work, it was decided to change over from the acid circuit in the mill to an alkaline circuit. The following description sets out the procedure adopted, -and the results obtained when such change-over was made.The Zinc Corporation ore consists mainly of galena, marmatite, calcite, and quartz, with smaller quantities of pyrite, fluorspar, and rhodonite.A clean specimen of marmatite picked from the ore assayed 53.4% zinc, and 10% iron, with no lead or insoluble. However, as zinc concentrates have been, at times, produced in the plant assaying over 53% zinc, and with only 8.7% iron, apparently the picked specimen of marmatite did not represent an average composition.The average would probltbly be between 8 and 9% of iron, and from 53.5 to 54.5% of zinc. It is obvious, therefore, that from this ore it is not possible to produce zinc concentrate of a higher grade than this average figure.In the Colorado School of Mines Quarterly for April, 1928, Vol. 23, No. 2, on page 47, we find the following statement:As the zinc in the ore exists as marmatite, which contains approximately 54.5% zinc and 10% iron, 49% zinc in the concentrate may be considered high.This statement refers to the ore treated in the Sullivan concentrator, owned by the Consolidated Mining and Smelting Company of Canada Limited.

Jan 1, 1930

By D T. Feinstein, M B. Gotkowitz

In Wisconsin, state laws and regulations governing metallic mine permitting stipulate that protection of groundwater quality be assured indefinitely through all phases of the mining project, including development, active mining, reclamation, and long-term closure. By rule, the Wisconsin Department of Natural Resources (WDNR) requires that permit applicants use a numerical model to assist in the assessment of compliance with this requirement for all proposed mine-waste facilities. As a part of the compliance assessment, model calculations are used to predict groundwater solute concentrations through time at designated boundaries for comparison to current groundwater quality standards. In practice, this modelling requirement has involved the application of numerical solute-transport models. Our review of a solute-transport model submitted by the developers of a proposed mine near Crandon, Wisconsin, provides us with an opportunity to assess the usefulness of transport modelling as a permitting requirement. Recent evaluations of solute-transport models by other workers suggest limitations in predictive accuracy. Our review of the model submitted for this project also identified important limitations due primarily to uncertainty in calibration of model parameters at the undeveloped site. The utility of any model to predict project compliance or non-compliance with numerical standards is limited by the range of uncertainty of key model parameters, such as dispersivity and porosity. Uncertainty in the future behaviour of the solute source(s) also reduces the predictive power. Moreover, the site characterisation provided by the model may have limited power to describe the site condition post-development. Although these inherent shortcomings accompany the use of solute transport models at undeveloped sites, the requirement for model development and the ensuing technical review has substantially assisted in our evaluation of site conditions and project design. Through this process we have identified elements of the waste facility design that are crucial to the environmental viability of the project, resulting in modifications to original project proposals. While results from this model review will be used to evaluate compliance, additional benefits come from the identification of critical design features that enhance groundwater protection.

Jan 1, 2003

By K Kuganathan, Y Potvin

Enterprise Mine at Mount Isa is to expand ore production from the current 1.4 to 3.5 mtpa by mining the 3500 Orebody, from which production is scheduled to start in February 1998 making this the deepest underground mine in Australia with its lowest mining horizon at nearly 1.6 km below surface. The following fill requirements were defined for the 3500 Orebody during the feasibility study: a minimum filling rate of 250 m3/h, a curing time of 28 days, and minimum free fill water. This paper mainly describes the investigation of high density and paste fills for the 3500 Orebody. The investigation covered all the key issues relating to fill option selection, including design criteria, material supply and demand assessment, drainage modelling, tailing dewatering method, mix design and a pump loop test. Results of the investigation indicate that both high density fill and paste fill are technically feasible. The investigation has led to the selection of a blended tailing paste for the 3500 Orebody as the paste option has significant advantages over high density fill in stope filling rates and fill reticulation. The blended tailing for paste fill is finer than Isa deslimed tailing but coarser than full plant tailing. The paste fill selected has minimum binder and tailing dewatering requirements while a relatively high filling rate is achieved.

Jan 1, 1998

By P N. Nkrumah, A van der Ent, G Echevarria, P D. Erskine

Nickel phytomining is a low cost alternative to traditional nickel mining and a complementary process to existing mining operations in areas with low-grade nickel soils or nickel waste material. The process of nickel phytomining consists of growing selected hyperaccumulator plant species (‘metal crops’) on Ni-rich (ultramafic) soils, followed by harvesting and incineration of the biomass to produce a ‘bio-ore’ from which Ni salts or Ni metal may be recovered (Chaney et al, 2007). The ‘metal crops’ are selected on the basis of high biomass yield combined with high Ni concentrations (>1 per cent) in the above-ground biomass (Chaney et al, 2007). Currently, Alyssum murale and A. corsicum have been used for Ni phytomining trials, mainly undertaken in Albania and USA (Bani et al, 2015; Li et al, 2003), while the agronomy of <10 species has been tested in temperate regions (Nkrumah et al, 2016). Nickel phytomining has high economic potential; however, large-scale demonstrations are needed to provide ‘real-life’ evidence for commercial operations (van der Ent et al, 2015). Unrealised opportunities exist in tropical regions for commercial scale Ni phytomining. To date, the agronomy of tropical ‘metal crops’ has not been tested. This extended abstract presents the progress of tropical phytomining, and reports on agronomic trials undertaken to determine whether the trends in temperate regions could be confirmed in a wet tropical environment.CITATION:Nkrumah, P N, Erskine, P D, Echevarria, G and van der Ent, A, 2016. Progress in tropical nickel phytomining, in Proceedings Life-of-Mine 2016 Conference, pp 135–137 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By T Laing, M A. Abdalla, P Hagan

Open pit operators are facing a number of challenges in the area of blasting and blasting processes, such as wall control, quality of fragmentation, explosives consumption and vibration. Remaining financially viable is one of the most significant objectives for mining professionals as they work through the blasting challenges within the mining chain of processes. This objective is such a significant challenge, primarily due to the high consumption of materials and the direct consequences on the downstream processes in the mining work flow, including loading, hauling, crushing, milling and mineral concentration. This paper reviews and discusses a technique to achieve this objective, namely air-decking. The performance in a number of mines around the world is reviewed focusing on the economic contributions of air-deck blasting. Various scenarios are investigated and simulated, covering both conventional and air-deck blasting, using JKSimblast software. The scenarios explore a range of issues and found that optimum results could be achieved with a minimum amount of explosives. The results obtained from the simulations were verified with blasts at Rixs Creek Coal Mine, Australia. Based on the verification results the simulations were then modified to more accurately model the actual conditions and parameters on site and to ensure that the models derived meet the production and control requirements at the mine site. Ultimately, overall analysis and comparisons were applied to the outcomes of the conventional and air-decking blasts revealing a reduction in material consumption of around 25 per cent with consequential savings and up to a 30 per cent reduction in ground vibration.CITATION:Abdalla, M A, Laing, T and Hagan, P, 2012. The contribution of air-deck blasting to open pit mining economics, in Proceedings Eighth Open Pit OperatorsÆ Conference , pp 7-12 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 18, 2012

By M Henderson, M Hudyma

Mining-induced seismicity at Junction Gold Mine became a serious operational problem in the late-1990s. Assessing the local seismic hazard is an important step in assessing the risk associated with potential rockbursting. This paper discusses the qualitative and quantitative means of assessing seismic hazard used at Junction. In qualitative hazard assessment, the role of the primary factors contributing to mining-induced seismicity and rockbursting are identified. These factors include: rock mass properties, geological structures, mine development, and stoping. A qualitative seismic hazard map has been developed considering these factors. In quantitative hazard assessment, seismic source parameters from an Integrated Seismic System are used to assess seismic hazard. The seismic source parameters found to be relevant to seismic hazard assessment at Junction are discussed.

Jan 1, 2002

The discovery of gold mineralization at the Manhattan mercury mine, Napa and Yolo counties, California in 1978 was the result of applying a new exploration ore deposit model in a region previously unprospected for gold. This discovery, the McLaughlin gold mine, owned and operated by Home-stake Mining Company, is a classic epithermal mercury-hot springs-gold deposit currently producing approximately 7,776,000 grams of gold annually.The exploration program that led to this discovery was based on a mercury-hot springs-gold genetic model. The model was developed using basic knowledge of ore-forming processes plus careful field observations made during examination of many known precious metal districts in. the Western U.S.A. Theoretically, hot spring systems could host gold deposits and, indeed, gold in these environments had been recognized for years. However, at the time of the McLaughlin discovery, it was not known to occur in sufficient quantities to inspire geologists to explore hot spring systems specifically for gold. Field observations recognized the presence of hot spring deposits and mercury mineralization asso-ciated with precious metal districts, (Bodie, California being a type example), and this associ-ation prompted the development of a hypothetical model. Subsequent exploration activities were directed towards the examination of mercury mines and prospects as potential targets for gold deposits. The model envisioned hot spring deposits (sinter) containing mercury mineralization at the surface with anomalous gold values grading downward into significant ore grade gold values.

Jan 1, 1990

By N Power, A D. Costar

There has been significant growth in mining and energy exploration in South Australia, which has identified new major potential opportunities. This sector generates significant economic value to the state and their support remains a priority for the state government. The delivery of this economic and associated community value to the state is dependent on the mining and energy sector being able to access reliable water supplies.The vast majority of priority areas for the mining and energy sectors are located in areas that have traditionally been of low priority from a water-use perspective and hence, data and knowledge levels are generally low.Recent studies have identified a potential increase in demand for water in the mining and energy sector for potential developments from approximately 40 GL to over 170 GL over the next ten years. The studies found that water and water infrastructure is the second highest proportion of planned infrastructure capital investment by resource companies. The South Australian GovernmentÆs Plan for Accelerating Exploration (PACE) initiative (PACE 2020), also identifies addressing the issues of location, use and management of South AustraliaÆs water resources as a key priority for the growth of the mining and energy sector.The Department of Environment, Water and Natural Resources (DEWNR) has developed the facilitating long-term outback water solution (FLOWS) initiative. DEWNR is currently undertaking a suite of programs to provide groundwater information at the regional scale to better target water supply options for mining and energy developments and community water supplies.The Goyder Institute for Water Research has leveraged significant research investment of $3 M to develop methodologies to interpret airborne geophysics to map groundwater sources.The FLOWS Initiative will provide key content for the PACE Water Program and will also assist in the development of water supplies for remote far north communities by identifying alternate groundwater sources to improve water supply security.This paper will discuss how developing an appropriate science and knowledge base will encourage and secure development where appropriate, enable prudent decision-making and policies regarding water allocation, accounting and licensing, whilst ensuring the protection of environmental assets.CITATION:Power, N and Costar, A D, 2013. Finding long-term outback water solutions, in Proceedings Water in Mining 2013 , pp 191-196 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

By L Torckler, J Hobbins

Favona is a blind low-sulfidation epithermal vein deposit in the Waihi Vein System approximately two kilometres east of the world class Martha Hill deposit that has produced nearly 6.8 M oz Au to date. The Favona epithermal system has surface expression in variously altered and mineralised hydrothermal eruption breccias forming a series of low hills that are windows through post mineral dacites and ignimbrites. The tip line of the Favona vein is about 50 û 100 m below surface with a steeply east dipping principal vein structure carrying numerous hanging wall splays in the upper flatter section and thickening down dip where the vein steepens. Host rocks comprise feldspar phyric andesite flows with minor pyroclastics. Although Favona has a strike length in excess of 1000 m and vein widths up to 25 m over a vertical range in excess of 400 m it was only recently discovered after nearly thirty years of exploration by various companies involved in the Martha Hill joint venture that operates the Martha Mine. Since discovery in 2001 a feasibility study based on 27.5 km of diamond drilling in 83 holes has been completed reporting a reserve of 1 Mt @ 10 g/t Au against a resource of 1.8 Mt @ 10.3 g/t Au. Exploration is continuing with a further 20.5km of diamond drilling completed to date on nearby prospects.

Jan 1, 2004

By J Zhou, X Bi, Y Yan, W Peng, H Yang, D Weng, P Li

Fortescue Metals Group (FMG) fines from Western Australia is a hematite and limonite mix characterised by high crystal water content. Due to its higher supply capacity and lower prices, the Wuhan Iron and Steel Corporation (Group) intended to use more FMG fines in the sinter mix. It is understood that sinter quality is closely related to its microstructure featured by the hardness and brittleness of different mineral phases, the content of micro pores, and trans-cracks. In order to maintain sinter qualities such as tumble index, reducibility and so on at higher FMG fines blend ratios, a research project was initiated to study the effects of the FMG fines blending ratio on sinter microstructure. Research results showed that at higher FMG fines ratios, the hardness of hematite and magnetite were both decreased while the hardness of calcium ferrite showed a tendency to decrease. The number of cracks that were generated during Vickers hardness measurement in various mineral phases decreased, but their length was shortened, and the variation of crack lengths increased. The contents of hematite and magnetite were also reduced and the reduction of magnetite was clearer. Also the content of calcium ferrite and pores rose and the magnitude of the increase of pores was greater. Among all the mineral phases in sinter cakes, the Vickers hardness of hematite was highest within the range of 879 N/mm2 ~ 942 N/mm2, and therefore the decrease of its content in sinter and the enhancement of its brittleness, ie the number of cracks increased, were harmful to sinter strength. In addition, the excessive increase in pores content is also not favourable to sinter strength.CITATION:Bi, X, Yan, Y, Zhou, J, Peng, W, Li, P, Yang, H and Weng, D, 2013. Study of sinter microstructure with various blend ratios of Fortescue Metals Group fines, in Proceedings Iron Ore 2013 , pp 331-336 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013