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The Resource Management Act has been in force now for approximately ten months. This Act, and the Crown Minerals Act which accompanied it, have substantially changed the manner by which mining operations and other resource uses obtain access to resources and are subject to controls of their environmental effects. This paper briefly summarises the key elements of the regulatory provisions of the Resource Management Act. It identifies the types of resource consents required, and discusses these and procedural matters in relation to mining in Otago. It addresses the transitional provisions and highlights inconsistencies and difficulties in the implementation of these provisions. This paper identifies potential future developments in the planning and regulatory environment relating to mining in Otago.

Jan 1, 1992

By J Zhou, D M. Hunter, S M. Iveson, K P. Galvin

The recovery and concentration of ultra-fine iron ore can provide significant economic benefits. Presently, there are limited options available given the low settling rates achieved by conventional gravity separation and the relatively poor performance of reverse flotation. The Reflux Classifier is a new water-based gravity separation technology that consists of a set of parallel inclined channels positioned above a vertical fluidised section. This arrangement promotes a powerful throughput advantage compared to conventional fluidisation and a highly selective hydrodynamic basis for achieving sharp separations. A high shear rate develops within the inclined channels, which generates sufficient hydrodynamic lift to convey the lower-density particles (even if they are relatively coarse) to overflow while retaining the high-density particles (even those that are ultra-fine) for discharge to the underflow. The technology has previously been used around the world on particle sizes in excess of 0.1 mm. The present work, however, is concerned with density-based separations down to much finer particle sizes approaching 0.01 mm.A major advantage of the Reflux Classifier technology is the achievement of simultaneous gravity separation and desliming via a single-stage separation. A series of continuous experiments was conducted using an iron ore feed with head grade of 35 wt per cent FeT and nominal top size of 0.106 mm, with 59 wt per cent being below 0.038 mm in size. At a low throughput of 1.5 t/(m2 h), the Reflux Classifier produced high-grade products at a high recovery. For the entire feed, grades of 66.1 wt per cent FeT with Fe recoveries of 80 per cent were achieved in a single-stage separation. Within the 0.020–0.038 mm size fraction, grades of 68.8 per cent were achieved with iron recoveries of 94.7 per cent. Excellent recoveries of up to 57.0 per cent were achieved for the -0.020 mm size fraction. The ability of the inclined channels to retain the fine dense material further enhances the effectiveness of the Reflux Classifier by creating an autogenous dense medium effect within the vertical section. This helps to elevate large gangue particles up into the overflow.CITATION:Hunter, D M, Zhou, J, Iveson, S M and Galvin, K P, 2015. Gravity separation of ultra-fine iron ore in the reflux classifier, in Proceedings Iron Ore 2015, pp 143–148 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

The traditional measure of Lost Time Injury Frequency Rate (LTIFR) as a measure of improvement in safety performance is recognised as inadequate and misleading, lulling managers into believing that safety is improving. It is a reactive measure, and steadily declining LTIFRs around the world have failed to be accompanied by a similar reduction in the fatality rate. This paper confronts the industry with the attitudes of some mining managers, such as one that allowed fatalities to occur in the case of a gold mining company at a rate of one death per 150 000 ounces of gold produced while claiming their safety record has improved, as shown by a falling LTIFR, and viewing fatality reductions as a long-term goal instead of an immediate priority. A quantum shift in management attitudes is required to focus on proactive measurements to detect the indicators of an impending disaster, and to predict conditions conducive to fatalities. Corporate CEOs are challenged to attend the funerals of all workers killed in the workplace. CEOs who fail to attend such funerals send a message to employees that the CEOÆs priorities lie elsewhere, and that profits take priority over workersÆ lives. The dichotomy of whether mining companies are run for the benefit of shareholders or whether companies owe social responsibility to the community is examined. The role of individual responsibility for personal safety is examined, together with the psychology of employees in the mining industry. A number of proactive measurable indicators are suggested to stimulate discussion on developing robust measuring tools to predict and therefore prevent fatalities.

Jan 1, 2003

By O Salisbury

Ingress of air into the longwall goaf environment needs to be managed appropriately to reduce the risk of creating a spontaneous combustion event. The maingate goaf edge is an area of particular concern in this respect, as air often penetrates for some distance into the goaf along this region inbye of the longwall face. Since the flow rate in this part of the goaf is also quite low, an opportunity exists to disrupt the air pathway by implementing a barrier to the airflow. Previous attempts using plugs made from an assortment of materials have resulted in varying degrees of success. More recently, Narrabri Coal Operations (NCO) has introduced the use of a chemical foam that is mixed with nitrogen to produce a standing barrier with the consistency of shaving cream. The implementation of this practice has consistently proven to be very effective for reducing the oxygen concentration along the maingate goaf edge by systematically retreating the foaming unit with the longwall. This paper presents how the foam is applied in the underground goaf environment to prevent oxygen ingress and uses results from gas monitoring to confirm the foam effectiveness.

Oct 12, 2022

By T Walton, C Perring, M Pepper, G Gerber

The Yandicoogina Channel Iron Deposit (CID) is an accumulation of iron pisolites cemented by a goethite-rich matrix. The Yandicoogina CID’s are found in a palaeochannel that meanders within a broad structural basin of the Yandicoogina Syncline in Pilbara region of Western Australia. RTIO Yandicoogina Mine Geology team contributed to a number of strategies maximising the iron ore reserves mined by Rio Tinto. Two strategies are discussed: the replacement of the Batter-Berm final pit walls by contour dozing; and upgrading the lower grade material to crusher feed. 1. Contour dozing – traditional Batter-Berm pit final wall configuration left kilometre long wedges of ore sterilised around bench margins. Contour dozing final walls (ie dozing of ore down the ore-waste contact) as internally defined by RTIO Yandicoogina Mine Geology (Mine Geology), enabled recovery of additional crusher feed. 2. Upgrade of lower grade material – the lower ore domain (GVL) within the Yandicoogina orebody contains numerous clay pods. Contaminant Al2O3 inherent within clay pods can result in CID material outside of crusher feed grade specifications, causing it to be flagged as ‘internal waste’ in mining models and permanently lost to waste dumps. In 2011, after multiple tests, Mine Geology demonstrated that this material could be upgraded to crusher feed via wet processing. With the support of the RTIO Metallurgical Development team new grade specifications were defined. The resulting material has been used to supplement higher grade ore. While increasing the mining ore output, these ongoing value-adding strategies also promote more sustainable mining via better use of the non-renewable iron ore commodity. The initiatives extend mine life, reduce waste movement, improve strip ratio and increase productivity

Mar 22, 2022

By D Kilkenny

This paper discusses the use of a mechanised shaft sinking machine Herrenknecht Vertical Shaft Sinking Machine (VSM) – to conduct the 93 m presink for the Wira Hoisting Shaft at the Prominent Hill Mine in South Australia. This technology has been widely used in the global construction industry, however, this was the first time it had been used in Australia and the second time in a mining application. The non-entry shaft sinking system eliminates risks associated with a traditional manual method and allows all shaft construction operation to take place from surface. The geology in the upper 100 m at the Prominent Hill mine is conducive to mechanical excavation, with expected rock strengths below 130 MPa. This enabled an alternative shaft construction methodology to be considered. The Herrenknecht VSM system was selected due to its extensive work history and demonstrated performance in similar ground conditions. In collaboration with the operations and design team, the shaft collar and surface configuration were modified to suit the requirements of the VSM, additional equipment, and loading jacks that support the pre-cast lining. Dedicated concrete moulds were designed in Germany and built in Italy. The concrete segments were cast in Adelaide and road freighted to site. This paper outlines each stage of the presink – refurbishment, transportation, logistics, establishment, operation and demobilisation. Selecting this shaft presink excavation methodology, delivered through positive collaboration and communication despite some challenges, shows the benefit to the mining industry of applying new technology and innovation to improve safety and productivity.

Mar 29, 2023

By M Ireland

Extensive use of diesel-powered mobile equipment in modern mines for materials handling, such as load-haul-dump machines, constitute a significant source of heat, exhaust gases and diesel particulate matter. Provision of sufficient quantities of fresh, cool air are required to remove such atmospheric contaminants from the environment for miners, particularly at depths where ventilation constraints and associated operating costs have an increasingly adverse impact. An alternative solution to diesel equipment to combat economic, environmental, social and health challenges, are battery electric vehicles (BEV), with the potential to expand production and substantially reduce ventilation and cooling demand, subsequently reducing operating costs. In this context, this paper focuses on the introduction of a battery electric loader to a diesel fleet at one of the deepest underground mines in Australia, the CSA Mine, a high-grade copper operation in Cobar, New South Wales. Analysis of a trial battery electric loader compared to existing diesel machines is performed with regards to infrastructure, technical and operational issues. Key benefits of battery electric vehicles over conventional diesel-powered vehicles are discussed, including lower energy consumption and greater efficiency, reduction of emissions and heat, reduced need for ventilation and lower operating costs. Challenges of introducing BEVs into an operation, along with the results from the comparative study are addressed under impacts to energy consumption, equipment selection, effects on ventilation and cooling, mine design and economic viability for future fleet implementation scenarios whilst meeting production targets.

Mar 29, 2023

By C R. Ure

To substantially reduce, if not eliminate, carbon dioxide (CO₂) emissions from ironmaking it is necessary to convert from blast furnace (BF) ironmaking using coking coal as the reductant to direct reduction (DR) ironmaking using hydrogen (H₂) and green electricity. Currently, almost all natural gas (NG) based direct reduced iron (DRI) production utilises iron oxide pellets in shaft furnaces, as opposed to fines in fluidised beds. Also, these pellets are ordinarily produced from high-grade magnetite concentrate, rather than hematite and goethite with typically higher gangue contents. The use of high-grade magnetite concentrate is driven by the preference to melt DRI in conventional electric arc furnaces (EAFs), thereby avoiding the basic oxygen furnace (BOF) for making crude steel (CS). However, in replacing BF with DR ironmaking it is not economically feasible to source enough high-grade magnetite to replace the lower grade hematite and goethite currently consumed. That is not to say that hematite and goethite, or even low-grade magnetite, cannot be used in DR ironmaking. However, their higher gangue content, resulting in higher slag production, requires that the EAF producing CS be replaced with a submerged arc furnace (SAF) that will produce pig iron (PI) for the BOF as does the BF. Here, critical issues to be addressed are, what are the technicalities in replacing high-grade magnetite concentrate with hematite and goethite and NG with H₂ in DRI pellet production and melting? This paper summarises certain relevant published information on DRI pellet research, test work and production together with relevant information on Pilbara ores. It attempts to illustrate the inter- relationship of composition and processing conditions on DRI pellet properties. It is intended to serve as a rudimentary guide to understanding the complexities of formulation, testing, evaluation, production and goethite and offer insight into this challenge.

Sep 18, 2023

By Eggleton R. A, Taylor G

As the search for major orebodies continues, the regolith dominated areas of the Broken Hill region remain one of the major exploration frontiers. The past exploration philosophies emphasising bedrock related characteristics have been limited in their ability to effectively explore in the regolith dominated areas, that are a feature of most of the Broken Hill region (Figure 1). If mineral exploration is to be more effective across all of the Broken Hill region, particularly in the regolith dominated areas, an appreciation and increased understanding of the regolith and landscape features are a necessity. Ironically, there have been very few studies of the regional regolith and landscape features of this region. Owing to the previous lack of an established regolith-landform framework, this study initially concentrated on the general characterisation and variation in regolith types corresponding to the area of the Broken Hill Block, within NSW (Willis, 1989; Stevens, 1986). The approach has been to produce a regional regolith-landform map at 1:100 000 scale and conduct a complimentary program of regolith sampling and site descriptions. This was a basis to identify areas for more detailed regolith-landform mapping (1:25 000 scale) and for producing a regional stratigraphic framework and models for landscape and regolith evolution. This information can then be used to provide a basis for regional mineral exploration models and strategies. This paper highlights some of the regionally significant regolith-landform features and their general significance to mineral exploration. More detailed information on specific regolith-landform features and study sites may be found in Hill et al (1994; 1996; in press) and Hill (in prep).

Jan 1, 1997

By H Wen

LongWangGou coalmine auxiliary inclined shaft heading face has a large section, fast heading speed, and large dust production. The problems of high concentration and wide distribution of dust in the roadway air are very prominent. To improve the efficiency of roadway ventilation and dustremoval, long-compression and short-suction (after this referred to as LCSS) are adopted. The dust concentration and airflow field distribution in the roadway are numerically simulated by FLUENT. The change of the position between the pressure duct and the exhaust duct and the different pressure-extraction ratios affect the distribution of airflow velocity, the formation of vortex zone, and the distribution of dust concentration in the roadway. When Ly = 25 m, Lc = 5.0 m, W = 1.2, a wind curtain is formed at 5 m in front of the heading face to prevent dust from spreading deeper into the roadway.

Oct 12, 2022

By J Folwell, G Phillips, F Gassner

Geomembranes selected for various applications often start with considering target properties developed by industry organisations such as Geosynthetic Research Institute (GRI), and test methods developed by ASTM and other Standards organisations The geomembrane types are typically, initially selected based on manufacturers recommendations and chemical resistance data from the manufacturer or industry knowledge. Geomembranes considered for this project included materials with material properties that exceeded the minimum target values of various test methods. The difficulty is in selecting which parameters are most important for a particular application and also what service life can be expected for the geomembrane under various chemical and environmental exposure conditions. Accelerated aging testing of candidate geomembranes in simulated exposure conditions can be useful to select the preferred geomembrane and predict the service life of the geomembrane under different exposure conditions. The exposure conditions of immersion in acidic tailings liquor, splash zone and freeboard zone were considered for evaporation ponds on a site with significant heat and UV radiation. Candidate geomembranes considered a range of different types of polyethylene liners. The results of the accelerated aging testing have allowed the selection of the geomembrane for the range of exposure conditions and evaluation of the expected service life of the geomembrane.

Jul 1, 2021

By Read T. A

PART 1The quantity of dust present and the methods used for suppression of dust in metalliferous mines has, in recent years, received considerable attention from mining engmeers in various parts of the world. Shortly after the publication of the General Report of the Miners' Phthisis Prevention Committee, South Africa, in 1916, the officers of the Broken Hill South Limited started investigations into the conditions of the dustiness of the air in the underground workings. As the methods used are not generally known in Australia, the writers are of the opinion that the present is an opportune time to place them before members of the Institute. A large amount of the subject matter of this paper has been drawn from the 1916 and 1919 reports of the Miners' Phthisis Prevention Committee, South Africa, the paper of Mr. Innes published in "The Chemical, Metallurgical and Mining Society of South Mrica"; also various articles appearing in the Journal of Industrial Hygiene, and the American Journal of Public Health. A great deal of research work into the cause, prevention and estimation of mine dust has been made by the Miners' Phthisis Prevention Committee of South Africa, and officials of the United States Bureau of Mines. The writers considered it advisable to begin the investigation at the South Mine with apparatus and methods developed by the South African Committee.Through the Australian agent of the Cape Explosives Company, inquiries were made preliminary to procuring the necessary apparatus for the determination of dust, from South Africa. The writers then learned that the older gravimetric method used by the Phthisis Prevention Committee was likely to be superseded by the konimeter...

Jan 1, 1922

By C Hedemann, N Silveste, H Davis, C J. Moran

For nearly two decades water scientists have been debating the need to use appropriate models for the questions being asked and the data available. This paper puts forward a rationale for a hierarchical framework for water balance modelling as it applies to mine sites. The hierarchy is based on the complexity of models and their data requirements. Scientific models are the most complex and require the most data; next is engineering models, then systems models and the simplest representations are given by conceptual models. A position is put forward that systems models have a range of uses that the others do not provide. A systems model, called SiteMiser, is described and its calibration illustrated. The model is applied to seven coal mines from the Northern Bowen Basin in Central Queensland. Currently, there is little relationship between total water use and coal production. This relationship is not any stronger when fresh (raw) water is compared to reused water. Leading practice water use levels are simulated for all sites. The simulation results demonstrate that there is considerable opportunity to reduce water consumption and, in particular, to import less fresh (raw) water to the sites.

Jan 1, 2006

By H Rossiter, C Simpson, J Market, P Jeanneau

Downhole Assay tools are a geophysical method to collect an instigated response from the material surrounding a drill hole and deliver a multielement proxy-assay. They were first tested in the Pilbara at the turn of this century, however since 2011 they have seen a more focused testing and implementation regime with multiple companies across multiple Pilbara mine sites. The increase in the volume of data has led to advances in the measurements and significant improvements to the efficiency of the calibration process. Pulsed Fast and Thermal Neutron Activation Analysis (PFTNA) downhole assay tools collect gamma photon spectra which are characteristic of elemental signatures. One of the key components of the technique is calibrating the spectral signatures to lab assays. Each tool is slightly different due to the organic nature of the crystal detector and therefore responds slightly differently. Environment and hole conditions as well as ore characteristics are among other external influencing factors. Thus, a unique calibration is required for each tool. In addition, not all elements are measured directly, but some are actually characterised by proxy, meaning that if the signal-to-noise ratio for an element is small, it may be easier to identify the mineral or geology in which that element is found and thus infer the concentration of the element. These proxies may differ for each site or geology type within a site. There is a large advantage to build a unique calibration per tool at each site rather than a universal one to be used across the whole province. This then delivers the accuracy and precision of measurements that mining companies require for modern operations. Early work with the tool required several thousand metres of calibration data and several weeks of analysis to build each calibration. This process has now been streamlined to significantly reduce the amount of data required and the analysis time to make it much easier to introduce new tools to a site with an existing model or to create new models. This paper details the calibration process, illustrating the increasing accuracy of the models as training data are acquired as well as the methods for transferring a calibration from one tool to another.

Nov 8, 2021

In February 1995, Falconbridge Limited approved the construction of a nickel mining and milling facility on its Raglan property situated in the Nunavik region of northern Quebec, Canada. The construction period successfully terminated with the commissioning and start-up of the plant and concentrator in early-December 1997. The estimated life of the project is 20 years with an annual mining rate of 800 000 tonnes of ore, producing 21 000 tonnes of nickel per year. This paper discusses the subject of æRemote Mining in the Canadian ArcticÆ as it applies to the Raglan mine process and people. During the feasibility stage of the project, many assumptions were made which influenced the design and operating parameters of the facilities and the equipment. Transportation, communication, remote logistics techniques and standard industry practices required to support a æfly-in/fly-outÆ operation were reviewed and either adopted or rejected for use at Raglan. These assumptions were æmade to fitÆ the uniqueness of our planned operation. It was also acknowledged that many of them would ultimately impact on the people required to staff the operation following construction. Therefore, their suitability and applicability were examined from an economic, operational and human perspective. In a continuing effort to improve the quality of life for Raglan employees, as well as the economics of our mine operations, these assumptions are under constant review and scrutiny. There is no doubt that experiences gained, and willingly shared by other North American arctic mining operations, proved invaluable and are a big reason for RaglanÆs overall success thus far. The mining industry is being challenged technically to develop lower grade orebodies at the lowest possible cost. In addition to environmental constraints, serious social, political and moral questions are being asked and added to this list of challenges. Miners throughout the world must improve their operating standards and public image if we want to attract the best possible employees. Remote mining operations provide a unique opportunity to experiment with various human resource concepts as well as demonstrate the industryÆs commitment to environmental and community concerns.

Jan 1, 1998

By R L. Grogan

Mining is currently undergoing a progressive expansion into novel environments (such as the deep ocean), commodities (such as tantalum, rare earths, and other ‘green economy minerals’), and new methods (such as the autonomous underwater cutting machines required to operate in the deep ocean environment, or the use of expanding grouts to deliver a blast-free mining method). The advent of novel mining, environments and commodities heralds an era that will undoubtedly start with much discomfort on the part of regulators and stakeholders, due to a feeling of overwhelming uncertainty. These proposed mining scenarios have few precedents, few examples of successful implementation, short baseline monitoring periods, and few examples of legacy sites that may assist with understanding long term risk and exposure. The evolution of the environmental and social impact assessment (ESIA) process in many regulatory environments recognises stakeholder engagement in a formal and facilitated manner. This is a positive step, and allows stakeholders to be much more meaningfully involved in the permitting process than they historically were. However, with this advance comes the challenge of identifying and communicating with stakeholders; sharing information in a meaningful way, fostering relationships with what can be an extremely large group, and delivering on commitments that inspire confidence to permit operations that have never been permitted before. In order to meet this challenge, it is suggested that changes to collection of data, communication of data, the nature of commitments, and the reporting of performance need to be made in order to effectively communicate management of new technologies, and the impacts that mining may have in new environments (such as the deep ocean). The communication challenge is necessarily greater when describing technology that has never been used, or environments that have never previously been accessed by humans on an industrial scale. CITATION:Grogan, R L, 2018. Permitting in the face of uncertainty – how to deliver confidence to regulators and investors, in Proceedings Life-of-Mine 2018, pp 46–48 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By Y Zhu, D J. Williams, M O’Neill, C Zhang, X Lei

A cover of inert material overlain by topsoil is required over compacted, seawater-neutralised red mud, a waste product from the refining of bauxite to produce alumina. The cover is to be revegetated, and it is necessary to demonstrate that the potential evapotranspirative-driven uptake of salts from the seawater-neutralised red mud will not impact the revegetation. An instrumented column was designed and constructed to test the evaporation-driven uptake of salts from compacted red mud into an overlying cover material with a thickness limited to 600 mm. The PVC column is 1.2 m high, with a 200 mm internal diameter. The column is instrumented with up to ten of each of moisture, suction, salinity and temperature sensors, together with a data logger, designed and manufactured at The University of Queensland (UQ) in Brisbane, Australia. The sensors were installed through the wall of the column at various depth intervals, with each set of sensors located at quarter points around the circumference of the column. Two pressure transducers were installed in the column to monitor the change of water level due to rainfall and evaporation. The column was filled with compacted red mud to a depth of 600 mm overlain by 600 mm of cover material, both sourced from the Queensland Alumina Limited (QAL) site in Gladstone, Queensland, Australia. The column is installed on a building roof at UQ, alongside a weather station, and will be subjected to the prevailing weather conditions for up to 1 year in the first instance, during which time the weather conditions and sensor responses will be continuously monitored. This paper reports on the instrumented column set-up and the early results obtained from the test.CITATION:Zhang, C, Williams, D J, Lei, X, Zhu, Y and O’Neill, M, 2018. Instrumented column testing of salt uptake from compacted red mud into a cover, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 220–226 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By N Clarke, A Barros

Preconcentration of run-of-mine subgrade and marginal ore by screening has the potential to substantially improve the economics of mining, particularly for large, low-grade orebodies, and to reduce environmental impacts. It has recently been the subject of a major research effort by a joint public-private research body, CRCORE. Yet despite this, there appears to have been only one fully commercial installation, at Bougainville Copper Limited in the late 1980s. Two reasons for the limited application are that not all ores have suitable properties and the economics of all pre-concentration processes on low-grade materials are highly sensitive to the precise balance of mass and value recovery and to the pre-concentration process cost, including materials handling. These factors make it imperative to have good test data on the process response of feedstock across the orebody. Collecting that data presents major challenges, which differ for green and brownfields operations. This paper first discusses the approach to preliminary evaluation developed by CRCORE, which relies on testing of coarse rejects or drill chips available from exploration drilling programs. This method is an efficient first step in evaluating an orebody which is deemed geologically to be potentially amenable to screen upgrading, but it does have limitations and must be followed by larger scale work. A suite of methods have been developed by the authors as a result of test work since the 1990s on several projects, supplemented by published data, which aim to provide statistically robust data at lower cost than large scale bulk sampling tests. For greenfields projects, the upgrade response measured on material crushed to -53 mm has been found to correlate closely with ROM ore, with no scale-up required for material with upgrade responses in the range of commercial interest. Large diameter whole drill core, such as PQ, is expected to be suitable for this method. As drilling such core is costly, the aim should be to establish relationships between upgrade performance and proxy measurements such as multi-element chemical or hyperspectral analyses. This approach was successful at the Gramalote gold project in Colombia. The method is not applicable for ores with thick vein material comparable with the crush size, but such material is not suitable for upgrading by screening and would be eliminated by the preliminary testing. For brownfields projects where blasted material can be sampled, the upgrade response can be accurately measured by sampling only the finer fraction of the ore, selecting a top size which represents 30–50 per cent or more of the ROM size distribution. This is likely to be between 50 and 100 mm. The much finer size compared with the full ROM ore greatly reduces the sample mass required to achieve a given intrinsic sampling error and enables sample preparation to be undertaken with large-scale laboratory equipment rather than mobile crushing plant. The accuracy of the method can be improved by measuring the approximate mass of oversize rejected during sampling. Some ores do show a systematic deviation from the assumed model fit which results in this method slightly underestimating the upgrade response, and it would therefore still be recommended to take one or two full bulk samples to confirm results before a final investment decision.

Aug 24, 2022

By M I. Pownceby, M A. Rhamdhani, D M. Fellicia, S Palanisamy, R Z. Mukhlis

The trend of global copper production has prospectively increased over time. Based on typical mined ore grades, 1 t of copper ore generates approximately 6–10 kg of copper, which requires much energy, usually in the form of metallurgical coke. Copper production using carbon as a fuel and reductant contributes up to 0.3 per cent to global greenhouse gas (GHG) emissions. As a result, research into decarbonisation processes applicable to reducing low-grade copper sulfide ores, copper oxides, electronic wastes and other alternative complex Cu-rich materials has increased. Alternative fuels for reducing carbon-rich emissions in pyrometallurgical copper processing include methane, ammonia, biomass, solar and wind power, but in recent times increased focus has been on hydrogen as a potential fuel and reducing agent for materials such as oxidised copper scrap, Cu2O/CuO and Cu-rich slags/e-wastes. From a thermodynamic perspective, hydrogen exhibits a significantly more negative standard Gibbs free energy (ΔG°) than copper oxide making it a suitable reductant and the exothermic thermal effect from reaction between hydrogen and Cu2O/CuO may be used to control process parameters. These characteristics renders hydrogen an ideal gas for reducing copper oxides and copper-containing slags/e-wastes. This review article assesses previous research on utilising hydrogen for producing and refining copper from primary and secondary feed materials.

Jun 19, 2024

By J Li, H Hooi, D Payne

Caval Ridge Mine (CVM) is one of the newly established open-cut coal mines of BHP in Queensland, where no tailings dam is planned to be built in order to minimise environmental impacts from mining activities. The waste streams from the Coal Handling and Processing Plant, including fine tailings dewatered by belt filter presses, coarse rejects, and mixed plant rejects, are co-disposed within waste dumps built with pre-strip and dragline spoils. Due to high rejects output (35 – 60% of feed) and low spoil to reject ratio (< 5) the large quantities of rejects bring significant geotechnical and operational challenges to CVM, which are exacerbated by increasing annual production rates and additional rejects from washing coal from an adjacent mine. Further in-house geotechnical review commenced in mid-2014 based on the initial geotechnical studies during the project stage of CVM between 2011 and 2013. The outcomes have enabled rejects disposal at CVM by constructing large belt filtered tailings cells, coarse rejects only dumps, and co-disposal of the mixed plant rejects at dump tip-heads. This paper presents the rejects disposal strategies at CVM from both technical and operational aspects. It also discusses future projects for belt filtered tailings moisture reduction including assessment of tailings clay mineralogy, as well as mixed plant reject co-disposal verification and optimisation.CITATION:Li, J, Payne, D and Hooi, H, 2018. Plant rejects disposal strategies applied at Caval Ridge open cut coal mine, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 50–60 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018