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By J R. Taylor, J A. Muchan, S M. Pape, B S. Davis

Acid and metalliferous drainage (AMD) is routinely derived from waste rock, tailings, pit wall rock, underground mine voids, heap leach pads, ore stockpiles, concentrate stockpiles and even slag piles. In many jurisdictions, there is an assumption that tailings materials represent the highest AMD risk. This is likely due to their highly sulfidic and ultra-fine grained nature, and the fact that they occur in large tonnage, partially unsaturated deposits. These characteristics are not unreasonably associated with reactive and therefore highly polluting mine waste materials. Interestingly, however, the high sulfide content and highly reactive nature of tailings achieves the rapid consumption of oxygen in tailings pore spaces. This oxygen depletion can limit or halt sulfide oxidation throughout much of the tailings pile. Oxygen can only be resupplied to the tailings via atmospheric exchange at the air-tailings interface. The grain size of most tailings materials limits this resupply to a diffusion related process that only affects the uppermost 100–2000 mm. Hence sulfide oxidation in tailings can be inherently self-limiting. Unfortunately, the same cannot be concluded for waste rock materials.Using a unique site assessment strategy that focuses on quantifying acidity fluxes from various domains at a mine site, it has become increasingly evident that sulfidic waste rock produces the majority (typically 60–80 per cent) of the soluble acid and metalliferous pollution at most active and decommissioned sulfide-bearing mine sites. Whether sulfidic waste rock is disposed in engineered above ground facilities, backfilled into pits or even underground voids, it remains the primary source of pollutants for decades to centuries.Conventional end-dumping waste rock practices result in angle-of-repose pathways for air and water, and these internal fabrics exacerbate sulfide oxidation (ie pollution generation) and discharge from waste rock materials. The primary aim of many cover systems is to retard the access of air and water to these conduits. Recent thinking is that more emphasis needs to be directed at strategic waste rock pile construction practices, and less reliance placed on thin soil cover systems to prevent AMD.Waste rock pile construction approaches that minimise porosity and permeability but raise the retained moisture content and enhance water residence times have the potential to lower sulfide oxidation rates and thereby improve water quality outcomes. For example, innovative base-up, layered and compacted (BULC) waste rock piles have the potential to avoid or minimise the generation of AMD, supersede the need for treatment and facilitate successful closure and relinquishment across the mining sector (Figure 1).CITATION:Taylor, J R, Pape, S M, Davis, B S and Muchan, J A, 2016. Waste rock pile construction to lower closure and relinquishment costs, in Proceedings Life-of-Mine 2016 Conference, pp 97–99 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By A Hocking, S Henderson

Commonwealth of Australia (2016) defines rehabilitation as comprising “the design and construction of landforms as well as the establishment of sustainable ecosystems or alternative vegetation, depending upon the desired post-operational land use”. For open cut coal mines in Queensland and New South Wales, the question of how to apply this intent to pits at mine closure is repeated for hundreds of individual pits. In EISs, closure plans and public discussion, assorted treatments are proposed to rehabilitate pits. While some aspects of final voids have been intensively studied, there is little guidance on how to choose a final void treatment option that delivers the optimal outcome against rehabilitation goals. For example, in the Bowen Basin and Hunter Valley commonly proposed rehabilitation actions include reducing the angles of pit walls; however, with few voids successfully rehabilitated to date there is limited understanding of what different wall slopes will achieve.CITATION:Henderson, S and Hocking, A, 2018. A decision framework for comparison of coal void rehabilitation options, in Proceedings Life-of-Mine 2018, pp 127–130 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By A-M Fleury

There has been much progress on the issue of acid drainage over the past 20 years; however, significant challenges remain. The International Network for Acid Prevention (INAP) is attempting to address them by globally coordinating acid drainage information sharing and research. INAP pursues three branches of activities: it links AD research, practice, and people; it organises, sponsors, and participates in regional workshops as a forum for technology transfer; and it instigates and funds key acid drainage research projects. Through these activities INAP is helping the industry deal with what is arguably its most serious legacy issue.

Jan 1, 2003

By J Joughin, D Kyan, L Rollin

In line with the 2015 Paris Agreement and corresponding climate disclosure requirements, many mining companies have publicly disclosed that they are developing and/or implementing ambitious decarbonisation strategies. Sometimes these strategies can be linked to the development of community programs and/or the creation of a positive legacy post-closure. Renewable power is key to most decarbonisation strategies – some mines will get this from external sources and others will establish on-site power generation and storage facilities. A range of options are available to develop renewable power generation (eg solar panel, wind farm, hydropower) and energy storage (eg battery, hydrogen, pumped hydroelectricity). Land access, impact assessments, planning and environmental approvals are required to establish new facilities. Host communities are more likely to be in favour of, or at least will accommodate, new power supply developments if these are planned with a benefit to the communities. Transitioning to renewables raises new challenges. Among these are high upfront costs and access to capital, energy demand variability, supply intermittency and variability, storage limitations, grid stability and reliability, transmission and distribution infrastructure constraints. Compounding these challenges are issues such as infrastructure resilience to extreme weather events (eg heat, wind), land use and access, lengthy permitting processes, community perceptions, skilled labour requirements, and meeting mine closure objectives. Renewable energy sources provide a more decentralised source of energy that reduces reliance on imported fuels, thereby increasing energy security and lowering production costs. On the contrary, implementing renewable energy could lead to potential negative impacts such as visual perception from the community, competitive land usage, electricity price raises due to upgrading infrastructure and the use of electricity storage capacities. As part of the definition of an environmental and social management plan, participative stakeholder engagement is required to identify benefits to the communities. For example, among the recognised benefits of developing solar panels (increase job opportunities, reduce soil erosion), various technologies have been experimented globally for the last ten years and are emerging due to their proven community benefits. Key findings to enhance those benefits can range from the development of innovative practices such as ‘agri-/aqua-voltaic’, ‘solar grazing’ to optimise land usage and stimulate the local economy (Table 1), to the implementation of technologies providing services to communities such as mobile water desalination plants or ‘smart grid’ systems to minimise energy clipping during peak-load of oversized renewable energy facilities (Table 2). While developing those synergies, careful management is required to avoid creating superfluous energy service needs from community programs. Energy sufficiency should remain a key principle according to the sufficiency, efficiency and renewable framework of the Intergovernmental Panel on Climate Change. Darby and Fawcett (2018) define energy sufficiency has ‘a state in which people’s basic needs for energy services are met equitably and ecological limits are respected’. Sufficiency tackles the causes of the environmental impacts of human activities by avoiding the demand for energy and materials over the life cycle of buildings and goods. Efficiency tackles the symptoms of the environmental impacts of human activities by improving energy and material intensities. The third pillar, renewables, tackles the consequences of the environmental impacts of human activities by reducing the carbon intensity of energy supply (Cabeza et al, 2022). Life of Mine Conference 2023 | Brisbane, Australia | 2–4 August 2023 34 This paper provides project developers, decision-makers and regulatory authorities with ideas on synergies between renewable energy options and community development programs. These can be considered to enhance stakeholders’ support for implementation of decarbonisation strategies.

Aug 2, 2023

By S Szylkarski, D N. Graham

In mining, water management is an operational necessity, requiring planning and detailed engineering, as well as risk assessment. Yet, the hydrology of streams and aquifers typically extends well beyond the boundaries of mine operations and intersect with environmental and social values. Mine managers often plan, design and assess the impact of water management activities (such as dewatering, excess water disposal and flood management) with a mine site or process specific focus. The challenge is that the impacts are spatial, long-term and complex – and may be cumulative across multiple mine sites. Further, there is usually little consideration of the feedbacks and interactions between surface water, groundwater and catchment hydrology. Failure to understand these processes can lead to poor decisions and increased costs. This presentation outlines an approach to simulating integrated hydrology in mining catchments that addresses the shortcomings of traditional modelling techniques.CITATION:Graham, D N and Szylkarski, S, 2016. Simulating integrated hydrology in mining catchments from planning to closure, in Proceedings Life-of-Mine 2016 Conference, pp 101–105 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By F Butler, G E. Batley, A C. Hogan, A R. Butler

The ANZECC/ARMCANZ (2000) Water Quality Guidelines (the Guidelines) are the primary reference used in Australia and New Zealand for managing and regulating water quality. For most mining operations in Queensland, the environmental authority (EA – licence) incorporates the national default guideline values (GVs) for ecosystem protection as trigger levels (TLs). Exceedances of TLs ‘trigger’ further investigation and reporting. A review of the surface water compliance history at a metalliferous mine in North West Queensland identified minor exceedances of the cobalt GV as a common trigger for investigation and compliance reporting.The reliability of GVs is dependent on the availability and quality of ecotoxicology data for the relevant contaminant. The current national default GV for cobalt of 1.4 µg/L is classified as a low reliability GV due to the lack of available data at the time it was derived (ANZECC/ARMCANZ, 2000).The Guidelines are presently being revised and the toxicant GVs will be available as a set of web-based values and associated technical briefs. The new platform will enable the timely revision of existing GVs and inclusion of GVs for additional toxicants. Cobalt was considered a priority toxicant for the Guidelines’ revision, but was not included in the revision process.A preliminary review of the international literature indicated that at least 15 additional chronic cobalt toxicity studies had been published since 2000, sufficient to derive a high reliability cobalt GV using the protocols developed for the revision of the Guidelines (Batley et al, 2014; Warne et al, 2015). This presented an opportunity to improve environmental management by increasing the reliability of the performance measure.CITATION:Hogan, A C, Butler, A R, Butler, F and Batley, G E, 2016. Derivation of high reliability water quality guideline values for cobalt in freshwaters – improving water quality guidelines for better water quality compliance management in mining, in Proceedings Life-of-Mine 2016 Conference , pp 205–208 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By L B. Zhou, S Li, B L. Wang, S B. Li, Q Wang

The rapid development in ChinaÆs metal mine resources has caused a series of mine environment problems such as serious ecological damage and environment pollution, and secondary geological disasters. The paper has reviewed ChinaÆs metal mine development, including current status and environmental situation, analysed existing problems in mine development and environmental management, and proposed corresponding countermeasures and suggestions.CITATION:Wang, B L, Li, S B, Li, S, Zhou, L B and Wang, Q, 2012. Current situations, problems, countermeasures and suggestions for ChinaÆs metal mine development, in Proceedings Life-of-Mine 2012 , pp 353-356 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By T W. C Stambolie

Longwall mining is a form of underground mining and the principal extraction method for underground coal mining in Australia. The method is used in the mining of both thermal and metallurgical coal. The primary market for thermal longwall mines is that of the export market where price is governed against the Newcastle Thermal Benchmark index (globalCOAL, 2016).Australia’s thermal coal export outlook is considered moderate due to slower demand from major importing countries, as well as slowing domestic production. However, ‘Australia is projected to increase its share of world thermal coal exports and become the world’s largest exporter over the medium term as lower prices, increased domestic use and infrastructure constraints limit growth from other key suppliers’ (Office of the Chief Economist (OCE), 2016, pp 25, 58). On the contrary, and as a result of current global coal price trends, the basic economic principles of underground longwall coal mining are heavily stressed. From a life-of-mine perspective, influencing return on investment is at its greatest during project evaluation and execution. Appropriate and realistic economic assessment is paramount to ensuring the right outcomes are achieved under the current economic challenges.CITATION:Stambolie, T W C, 2016. Thermal coal industry – is longwall mining currently a life-of-mine option in Australia?, in Proceedings Life-of-Mine 2016 Conference, pp 57–61 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By J Theiler, B Beamish

Spontaneous combustion hazard assessment from an environmental impact perspective is not well understood and is seldom given due consideration in environmental impact statements. In surface mining operations, self-heating, leading to spontaneous combustion may occur when rock units containing reactive metal sulphides and organic carbon are disturbed by mining operations and exposed to the atmosphere. When these rocks are present self-heating will occur in situations where the rate of heat generated from oxidation reactions exceeds the rate of heat lost to the surroundings. The processes and mechanisms that lead to spontaneous combustion events are varied and generally complex. To effectively manage spontaneous combustion in surface mining operations, it is necessary to characterise the spontaneous combustion propensity of the geological materials involved. Until recently there has been no testing procedure for assessing the propensity of waste rock to spontaneously combust that has been adopted by industry. However, new developments in adiabatic test methods have proven successful in determining the self-heating behaviour of coal (Beamish and Theiler, 2015) and coal containing reactive pyrite (Beamish and Theiler, 2017). These adiabatic test methods have now been modified to assess the incubation behaviour of waste rocks and can be used for their spontaneous combustion characterisation in advance of mining (Beamish and Theiler, 2016). The new method provides a practical means to establish the likelihood of developing a spontaneous combustion event for the specific site conditions. This paper presents examples of the use of a cost effective first pass filter for assessing spontaneous combustion potential of waste rock based on geochemical data from four surface mines. This is supported by adiabatic Incubation Test results for three of the mines and visual examination of cores for one of the mines. CITATION:Theiler, J and Beamish, B, 2018. Valid spontaneous combustion hazard assessment for surface mine environmental impact statements, in Proceedings Life-of-Mine 2018, pp 64–67 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By R Peiffer, L van Wyk

The Port of Port Hedland is the largest bulk export terminal in the world and is one of Australia’s most important pieces of economic infrastructure. BHP is the largest Port user to support the export of iron ore products from mines located within the Pilbara region of Western Australia (WA). BHP’s priority is the safety and well-being of its workforce and the communities where it operates. In a recent regulatory application to increase export capacity, BHP committed to the deployment of wind fences to reduce wind erosion from stockpiled ore. Wind erosion from stockpiles was identified through inverse modelling as the most significant dust source compared to other sources such as stackers, reclaimers, shiploaders and transfer stations. The primary cause of dust emissions from stockpiles is dust lift-off during high wind conditions. BHP proposed the installation of wind fences across its Port Hedland operations, targeted at reducing emissions from wind dependent sources, primarily stockpiles, by reducing the wind speed downwind of the wind fence. Modelling predicts that installation of the wind fence will significantly reduce emissions from stockpiles, particularly at BHP’s western operations (Finucane Island). To be effective in shielding stockyards and reducing wind speeds, the wind fences are located upwind and as close as practical to the open stockyards. BHP’s wind fence design incorporates learnings from other existing installations and has been tailored for Port Hedland’s cyclonic conditions. The wind fence will be higher than the stockpile height, with a mesh porosity of approximately 50 per cent. The mesh porosity allows some of the wind to pass through the mesh. This reduces the wind turbulence downstream of the wind fence, as opposed to a solid wind fence, which increases downwind turbulence, resulting in increased dust.

Sep 18, 2023

By R B. Venugopal, P Staples

The selection of the mode of transport for moving bulk materials is never a simple task as there are various concerns/considerations applied to the selection of the most practical and cost-effective mode of transport to be used to move bulk materials. This paper examines various alternatives for moving ore from a mine at the top of a mountain to a process plant below (some 5000 m apart and a vertical drop of 650 m). The terrain of the mountain section of the route has added its own specific requirements, resulting in the final selection of a pipe conveyor for this application. The paper further addresses the final selection of hardware used in the implementation of the solution.

Jan 1, 2005

By M Boyd

The University of Wollongong was named University of the Year 2000, for its work in preparing students for the e-world. Computer facilitated learning is being introduced into subjects throughout the engineering course. First year mining engineering students are introduced to computers, e-communication, using the UniversityÆs web based information system, and web based subject delivery. Mining engineering students in the mid-years of the course use programming languages and numerical computation software such as MATLAB, while students in the final years use a range of commercially available professional engineering software such as TALPAC. Most of these subjects are offered as part of the UniversityÆs Learning Online program, co-ordinated by its Centre for Educational Development and Interactive Resources (CEDIR). Learning Online subjects are delivered using the Web Course Tools (WebCT) environment. WebCT allows all resources to be accessed through the web, allows email communication between lecturer and student, and allows discussion groups for the exchange of ideas. Students can submit their assignments through WebCT and receive immediate feedback. This paper describes how WebCT has been used to deliver a first year engineering computing subject, mid-year numerical computation subjects, a mining economics subject and mine planning subjects.

Jan 1, 2002

By Baker G

Chromite was recorded among the rare minerals in the natural beach sand concentrates on the coast of Northern New South Wales by Whitworth(l) in 1931, and the commercial production of zircon and rutile from these beach sands has yielded concentrates of ilmenite with small amounts of chromium. The chromite is a detrimental impurity in the utilisation of the ilmenite, and the difficulties that attend the separation of the small amount of chromite from the ilmunite have raised suggestions from time to time that chromite occurs with ilmenite in composite grains. The absence of such composite grains and the nature of the chromite grains has been indicated by the following mineragraphic examination of magnetic concentrates containing chromite which were prepared by the C.S.I.R. Ore Dressing Laboratory, Melbourne University, from ilmenite concentrates from beach sands at Norrie's Head, County Rous, New South Wales and Stradbroke Island, Queensland.The magnetic concentrates from each locality are divided into five fractions, and the No. 1 concentrate is the most highly magnetic and the tailing the least magnetic. Chromium assays as determined by the Ore Dressing Laboratory are as follows:-

Jan 1, 1948

By H Kim, M J. Sun

Global steel companies are actively combating climate change by reducing carbon emissions. Traditional steel production, using the blast furnace (BF) – basic oxygen furnace (BOF) process, heavily depends on coal and emits substantial CO2. To mitigate this, companies are transitioning to the more eco-friendly DRP (direct reduction plant) – EAF (electric arc furnace) process, which lowers CO2 emissions. This study quantitatively evaluates the impact of increased hydrogen consumption on the carbon footprint of product (CFP) through an analysis of direct reduction process heat and mass balances. The study prioritises a comprehensive material balance based on mass conservation principles. The heat balance is calculated using differences in enthalpy through state energy properties, avoiding heat consumption. Validation using operational data from Hyundai Steel Dangjin works’ blast furnaces shows close alignment between calculated results and actual data, with less than 1 per cent error. This methodology facilitates a detailed analysis of the direct reduction process, offering insights into its feasibility and efficiency. Analysis of the operational impact by increasing the hydrogen ratio demonstrates reduced CO2 emissions and increased heat requirements due to the endothermic nature of hydrogen reduction, in contrast to the exothermic CO reduction. Possible solutions include raising reducing gas temperature or enhancing flow rate. The study effectively utilises designed heat and mass balances to assess material quantities and thermal balance under different operational conditions. It lays the foundation for the initial direct reduction process design, aiding in deriving and optimising operational parameters. Additionally, it provides valuable insights into the challenges of increased hydrogen, contributing to the production of greener steel by addressing these issues.

Aug 21, 2024

The adoption of new technologies is accompanied by risks that the stakeholders will wish to understand and minimise. The process of developing a dynamic simulation and the plant it will be used in provides a discipline and attention to detail that highlights and provides an opportunity to mitigate risks that will exist in a production environment. The simulations will enable investigation of what the outcome of process failures will be and the impact maintenance. Enumerating this information will enable designs to be optimised and operating and control strategies to be tested.The success of new technology is dependent on the operators and their understanding of it and the machines that use it. In this context dynamic simulations can provide training and experience without risk to personnel, equipment or production. This experience will include situations that would not be induced in a production plant for training purposes. This paper outlines a generic template for a dynamic simulation that can be used to evaluate the introduction of an emerging technology into an operating environment. It includes process flows and surge capacity, breakdown and maintenance, operator interactions and availability, push and pull production scheduling and system control.

Sep 26, 2011

Two characteristics of the modern mining industry are that there is a skill shortage and that young professional people rise rapidly into highly responsible supervisory positions. With this responsibility comes the burden of identifying and managing health and safety risks. Without the benefit of a comprehensive health and safety training program, these young professionals may be putting both themselves and those under their supervision at risk. The Moura Mine explosions and the asbestos health disaster should not be just artifacts of history, but highly valued lessons that impress the need for comprehensive health and safety risk management strategies on young professionals. From the perspective of the former secretary of the Committee to implement the findings of the Moura (Disaster) Inquiry and as the former coordinator of the Coal Workers Health Scheme, key issues in occupational health and safety management systems are explored.

Jan 1, 2005

A flow sheet has been developed to treat a high tonnage highly preg-robbing gold ore. The ore is low grade and fine grained with a high proportion of very fi ne free gold. The key components of the flow sheet include gravity, flotation, intensive cyanidation with direct electrowinning, and carbon-in-leach of the flotation concentrate. The circuit produces a low overall mass pull to concentrate allowing economic intensive treatment of large tonnage low-grade material. Efficient recovery of fine gravity gold using a Falcon concentrator in both the milling and flotation circuits, and subsequent intensive cyanidation in a Gekko InLine Leach Reactor (ILR) is critical to the process with over 70 per cent gold recovery expected in this circuit. Grind size control was also found to be important in controlling the activity of the preg-robbers in the carbon in leach circuit and also in the solid liquid separation performance. Tests at the large-scale demonstration plant have been conducted to demonstrate the effectiveness of this flow sheet. A large low-grade deposit is currently under development with the aim of developing a 10 Mt/a treatment plant with the subsequent addition of equivalent sized process lines in multiples of 10 Mt/a. The economic development of this orebody is critically dependant on understanding and exploiting the properties of the ore. In particular it is critical to minimise the effect of preg-robbers by recovering free gold with Falcon concentrators and InLine Leach Reactors. Recovery of the remaining gold by flotation into a small mass yield allows this fraction of gold to be treated by CIL leaching utilising high carbon levels. It is critical is to ensure operation at the optimal grind size to maximise liberation of the free gold and minimise pregrobber activity. The ore has been identified as preg-robbing with low recoveries obtained if treated using conventional cyanidation and carbon absorption. The mineralogy consists of predominantly fi ne grained free gold with minor sulfides including pyrite and arsenopyrite. With conventional cyanide leaching in the absence of carbon, gold recovery is less than 50 per cent. Direct cyanide leaching of the ore in the presence of activated carbon results in an improved but still uneconomic gold recovery. The gravity recoverable gold (GRG - as defined by Andre La Plante) content of the ore has been measured to be 70 per cent to 85 per cent in various tests with liberation grind size of approximately 106 ¦m. This indicates gold is predominantly free and suitable for recovery by batch centrifugal concentrators into a low mass yield. This property of the ore presents the opportunity to maximise the recovery of gold by separating it from the majority of the preg-robbers prior to leaching. Due to the very fine gold particle sizes and the necessity to maximise recovery of this fine fraction Falcon concentrators were selected for the duty, with their proven high recoveries at very fine gold sizes. The gravity recovery in the milling circuit is designed to be in the range 55 to 65 per cent. This has been achieved in the existing pilot plant using a Falcon operating on ball mill discharge within the mill recirculating load. Intensive leaching in an InLine Leach Reactor is essential to recover the gold from the gravity concentrates. Tabling is not a preferred option since recovery is lower than intensive cyanidation and any gold losses to table tails will report to CIL where recovery is reduced by the presence of preg-robbers. Furthermore, tabling recovery from the gravity concentrates is particularly poor due to the fine particle size of the free gold. ILR recoveries of 98 per cent were demonstrated in the pilot plant using an ILR100BA and leach conditions were investigated in the lab using pilot plant generated Falcon concentrate. Recovery of gold from the pregnant solution was achieved with direct electrowinning at pilot and efficiency and sizing parameters were determined at lab scale. To further increase free gold recovery Falcon concentrators will be installed in the flotation circuit. Location of the Falcons in the circuit is not finalised but installation on the rougher concentrate stream is favoured since it will allow multiple pass recovery. This is expected to recovery a further ten to 20 per cent of the gold, as indicated by lab tests on pilot plant generated material. The gravity concentrate from the flotation circuit will also be leached using InLine Leach Reactors. Initial intensive cyanidation tests carried out on lab generated flotation concentrates indicated higher recoveries than CIL can be obtained even though the concentrates contain significant levels of preg-robbing material. This can be explained by the high cyanide, high pH leaching conditions used in the ILR which alters the absorption equilibrium of the preg-robbers. Further optimisation of the leach conditions will be undertaken once more concentrate becomes available. Recovery of the remaining gold content is achieved by flotation into a small mass yield, however the preg-robbers are also recovered into this concentrate. Due to the presence of the preg-robbers gold leaching must be carried out in the presence of high levels of activated carbon in a CIL system. The recovery has been shown to be strongly dependant on the carbon loading and the concentrate particle size. The carbon competes against the preg-robbers for dissolved gold while excessive grinding increases the surface area and activity of the preg-robbers. This has been demonstrated in test work however the economic optimum leaching conditions and carbon loading have yet to be determined. The grind size is critical to the economics of the project, not only due to its effect on gold recovery but also due to its effect on the major operating and capital costs at both the front and back end of the process. It is critical to grind enough to obtain both gravity free gold and flotation liberation at low mass yields however over-grinding results in large increases in mill size and power at the front end and filtration or thickening costs at the tails. Because these unit operations treat essentially all the plant feed even small changes can result in major impacts on project economics. The viability of this project is greatly enhanced by the high recovery of gold into a small mass yield. In particular the production and intensive leaching of the free gold gravity concentrates will allow over 70 per cent of the gold to be recovered efficiently with minimal impact from preg-robbers. By using flotation the mass of the remaining fine preg-robber contaminated material, to be leached in CIL, is greatly reduced allowing this difficult material to be economically treated. This is an ABSTRACT ONLY. No paper was prepared for this presentation. 

Aug 1, 2010

By H Kim, M J. Sun

In order to reduce carbon emissions from the steelmaking process and achieve carbon neutrality, global steel companies are establishing their own medium to long-term strategies and implementation plans using competitive technological advantages held by each steel company. At this point, Hyundai Steel has formulated a product-oriented carbon-neutral strategy based on innovative processing that makes use of Hyundai Steel’s own strength. Based on our experience in electric arc furnace product manufacturing and blast furnace operation in an integrated steel mill, Hyundai Steel is driving the Hy3 (Hy-cube) project, which involves a unique hybrid production system utilising hydrogen and hydrogen-based renewable energy sources. This initiative aims to achieve carbon-neutral production and eventually specialise in producing premium carbon-neutral automotive parts. The project has originality in that it involves not only designing processes using electric furnaces to produce premium steel products such as car body panels and electrical steel sheets, but also aims to reduce carbon emissions from the process, developing carbon-neutral products based on market demand. To assess the feasibility of the Hy3 project, Hyundai Steel conducted two pilot productions. The first pilot was producing a prototype of lower-arm part using electric arc furnace with three different kinds of raw materials: molten iron, HBI (hot briquetted iron), and scrap. Successful performance evaluation of auto parts with 1 GPa strength was achieved. The second pilot has been focused on tire cord steel, with the first-phase tests yielding a 33 per cent reduction in carbon footprint (CFP). Using the advantages of operating experience in electric arc furnace, Hyundai Steel is preparing for test operations producing various automotive parts using an electric arc furnace (EAF) to advance the Hy3 concept. From a medium to long-term technological development perspective, Hyundai Steel’s blueprint includes producing high-end carbon-neutral steel products using hydrogen-reduced iron as raw material.

Jun 19, 2024

By W J. Haylock, K Wasiel

PX4 Software Pty Ltd is a Brisbane-based company, which specialises in providing tenement management software to mining and exploration teams operating in Australia and several international jurisdictions, including the United States, Africa, and Canada. Whilst the company is experiencing substantial growth due to a demand from both the minerals and mining technology sector, there is a crucial gap in the market for critical minerals, which will be required to achieve the net-zero emissions goal set by the Paris Agreement for 2050. To help understand and address the technology gap identified by the unprecedented demand, PX4 Software undertook the Annual Survey of Technological Transformation in the Exploration Industry. This survey involved interviews with 12 very distinguished subject matter experts in the fields of Geoscience and Geology from across the globe. From this survey, we have defined eight major categories of exploration technologies. Notably, the most transformative of these technologies over the past 65 years falls into the Geophysical Methodology category, specifically focusing on image and signal processing of both airborne and downhole data. Advances in computing power during this period have significantly improved data processing quality, enhancing orebody modelling, and targeting. This has had a profound impact on the industry. Moreover, the survey reveals that future transformative technologies are expected to centre on the automation of existing processes through AI and Machine Learning techniques. This is expected to help facilitate the identification of critical mineral systems and thus enable the exploration industry to make more informed decisions based on data analysis using Machine Learning and AI.

Sep 1, 2024

By A Fern, A Hawkes, o

This presentation will cover: the importance of high-quality safety leadership; insights from a Safety Climate Survey that includes responses from 7903 employees working at 19 Australian mining organisations; the results of a critical control verification (CCV) coaching intervention; and recommendations for improving safety leadership in high-risk work settings. Safety climate is a representation of the deeper culture that exists in an organisation. Safety climate is predictive of behaviour, performance and reporting in organisations. Leaders play an important role in the establishment and maintenance of culture. Perceptions of safety climate were collected from 19 Australian mines (n = 7903 employees). These results indicate that the Australian mining sector is doing well in team support for safety and supervisor safety commitment. There were negative perceptions of willingness to report errors, employee involvement in safety initiatives, psychological safety and emergency readiness. Perceptions of safety leadership were in the fair range, with recognising behaviours perceived lowest, falling in the poor range. The underreporting rate was at 25 per cent indicating that 1 in 4 incidents are not being reported. Analyses exploring climate, leadership, safety behaviour and well-being will also be discussed. The integrity and success of critical risk management systems is often determined by the quality of safety leadership. Leaders need a mix of technical safety knowledge and interpersonal skills to be able to support the workforce to build critical control knowledge that invites open and collaborative discussions to find new or improved solutions. Forty leaders at a major mining operation completed training and 5-weeks of coaching focused on developing critical control verification competencies. The follow-up evaluation demonstrated significant improvements in relationship building, observation of controls and overall capability. Overall, insights from multi-organisation climate data and a prepost coaching intervention will be discussed and recommendations and practical guidance for leaders will be provided.

Apr 16, 2024