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By H J. J Boshoff, A J. Karrasch

Mine planners frequently face the challenge of mitigating the impact of climatic events on mining operations, such as floods and droughts. Specific water management infrastructure can be implemented to meet operational requirements in response to these events. However, the effect of flood protection, for instance, may reduce the resilience of the site to drought. The probability and duration of unfavourable climate sequences significantly influences the net present value (NPV) of implementing specific water management infrastructure.Good life-of-mine planning will consider the incremental development of the project, and provide staged development plans. Water management infrastructure and the timing of implementation are facets of this process.CITATION:Boshoff, H J J and Karrasch, A J, 2016. A decision-making framework for water supply and flood protection options in net present value terms, in Proceedings Life-of-Mine 2016 Conference , pp 196–199 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By S D. Fox, P B. Swart

Statistics showing that mine rehabilitation is falling behind rates of disturbance continue to be reported in the media. Unfortunately, most reported statistics do not account for the large growth-cycle that mining in Australia experiences, where there are typically significant new disturbances with large portions of these areas not being available for rehabilitation for a number of years. Many commentators assert that better planning is required to ensure that rehabilitation will be able to achieve a safe, stable, non-polluting landform that meets the agreed post-mining landuse.This paper focusses on the revegetation aspects of mine rehabilitation and in particular the matters that need to be addressed in the planning stage so that revegetation success is ultimately able to be demonstrated to regulators and other stakeholders.CITATION:Fox, S D and Swart, P B, 2018. Planning revegetation for relinquishment, in Proceedings Life-of-Mine 2018, pp 113–115 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By J Isarua, R Mabiria

The Ok Tedi copper and gold project, located in the Western Province of Papua New Guinea, commenced operations in 1983. The open cut mine has undergone several significant transformations throughout its project life including changes of ownership, mine life extensions and varying production performance profiles. As of today, the Ok Tedi Mine is a 100 per cent PNG owned company (67 per cent State and 33 per cent Western Province and Communities) and has a life-ofmine plan extending out to about 2032.

May 5, 2022

By K Grohs, A Satriawan, S R. Pearce

Martabe gold and silver mine is operated by PT Agincourt Resources (PTAR) and is situated in northern Sumatra and comprises several deposits in steep terrain, and in a tropical climate, that are required to be developed in the optimal sequence for the best possible Net Present Value (NPV) return on the project. In addition, the waste rock from excavations and tailings from processing is a by-product to be scheduled and used for a number of purposes identified as part of life-of-mine planning. These uses include construction of the current integrated tailings storage facility (TSF) as well as future engineering construction and waste disposal projects which includes plans for a program of in-pit backfilling. These plans need to be aligned to ensure the waste rock and tailings can be contained relative to the production rate. Given that the site will have multiple open pit voids upon cessation of mining activities opportunities for integration of in-pit disposal of mine waste have now been assessed with technical studies to review the practicality of the approach with respect to operational challenges and conformance with closure planning requirements. This includes assessment of disposal of waste rock, tailings (including consideration of filtered tailings) and co-disposal of waste rock and filtered tailings.

Aug 2, 2023

By M Dalm

More and more mining companies are becoming aware of the potential benefits of sensor-based ore sorting and process optimisation. This is reflected by a growing number of analysers that are available for drill hole logging, conveyor belt scanning, ore sorting, slurry analysis, etc. These tools all rely on a specific sensor technology that can be used to detect a material property such as colour, density, mineralogy, or chemical elements. However, all sensors have restrictions on the minerals and/or elements that can be detected or inferred. This is caused by the physical mechanisms behind the technology and depends on mineral concentration and compositional heterogeneity of the ore. Since nearly every ore deposit is unique in composition and characterised by different geological features that drive heterogeneity, no one-size-fits-all sensor solution is available. This makes it difficult for mining professionals to find suitable sensing technologies that can help them solve problems and improve processes for their specific ore types.

Sep 1, 2024

By D Bush, F Goddard

The electrification of Australian mine sites will see a boom in the use of batteries of all chemistries. Lead acid batteries, a traditional mainstay of the mining industry, are expected to nearly double by 2030, however their use will be eclipsed by the explosive growth in lithium batteries. By 2030 the lithium battery market is forecast to be nearly four times the size of the lead acid battery market. Unfortunately, this will result in a corresponding avalanche of waste batteries to be disposed of. Barely a day goes by without battery generated fires being reported in the media and they have become an increasing nightmare for waste management companies and waste facilities. The safe recycling of batteries will also become increasingly important for mine sites to achieve their sustainability goals and reduce their environmental footprint. What are the risks posed by waste batteries, what are the regulatory requirements and how can you manage or eliminate these risks? What current practises does your mine site currently have for the safe management and disposal of batteries from your site? How prepared are you for the coming avalanche of waste batteries?

Apr 16, 2024

By I Lipton

The existence of metalliferous mineral deposits on the deep-sea floor has been known since manganese nodules were discovered in the Arctic Kara Sea in 1868. Modern exploration to define commercially viable base and precious metal deposits began in the 1970s and gained further momentum in the last decade. High grade deposits have been delineated but investors remain cautious, many considering deep sea mining projects to be riskier than terrestrial projects. This paper compares opportunities and risks presented by terrestrial mining projects with those presented by deep sea mineral deposits (Table 1). The Solwara 1 volcanic-hosted massive Cu-Au-Ag sulphide deposit, the Atlantis II Deeps sedimentary base metal sulphide deposit, and the Mn-Ni-Cu-Co nodule deposits of the north-eastern Pacific Ocean are used as examples. These are advanced deep-sea projects with published Mineral Resource estimates, on the cusp of development. Off-shore diamond mines in Namibia are also considered. These examples provide a basis for comparing exploration and geological uncertainty, the technical risks of proposed mining systems, and the potential environmental and social impacts. CITATION: Lipton, I, 2018. A comparison of opportunity and risk in deep-sea and terrestrial mining projects, in Proceedings Complex Orebodies Conference 2018, pp 102–105 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By R Morrison, P Walters, B Adair, V Jokovic

‘Grade Engineering<sub>®</sub> is an integrated approach to coarse rejection that matches a suite of separation technologies to ore specific characteristics and compares the net value of rejecting low value components in current feed streams to existing mine plans as part of a system-view’ (Walters, 2017). Two of these technologies are directly recoverable through screening stages: Natural Deportment and Induced Deportment. The potential for taking advantage of “Natural Deportment” by size following blasting and crushing has been demonstrated for a range of ore types. Simple and low cost screening can in some cases generate a fine product with improved grade and a lower grade oversize which can be directed to leach or to waste. Where an ore body consists of many different ore types, the traditional approach of blending to metal grade will often add to complexity of treatment, which will reduce the effect of “natural deportment” by size.CITATION: Jokovic, V, Walters, P, Adair, B and Morrison, R, 2018. Applying enhanced grade engineering to complex ore bodies, in Proceedings Complex Orebodies Conference 2018, pp 21–23 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By T Baumgartl, B Noller, B Forsyth, J Park, M Edraki, P Pham

Understanding and quantifying residual risk is the key to the successful closure and rehabilitation of mines. An important aspect of residual risk is predicting the long-term chemistry of mine water and the long-term geochemical stability of mining wastes. This requires updating the characterisation data for mine wastes and monitoring mine drainage throughout the life-of-mine. The intrinsic properties of waste materials (ie the geology, mineralogy and the weathering processes, which in turn depend on the local climate and water balance in a waste storage facility) are the fundamental controlling factors of residual risk. In this paper, case studies of coal and metalliferous mines are used to discuss the definition of residual risk for a range of waste storage facilities and to highlight the benefits and limitations of current geochemical methods in predicting and quantifying residual risk. Consistent with the classification of mine drainage by the Global Acid Rock Drainage Guide, three case studies of acid, saline and neutral drainage are presented.CITATION:Edraki, M, Pham, P, Park, J, Baumgartl, T, Noller, B and Forsyth, B, 2016. Defining residual risk for successful mine closure – a geochemical perspective, in Proceedings Life-of-Mine 2016 Conference , pp 9–11 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By N J. Grigg

Gekko Systems has developed an underground pre-concentration plant (Python) to reduce mine operating costs. Many ores liberate favourably using either high pressure grinding rolls (HPGR) or vertical shaft impactors (VSI). Using these comminution circuits for mineral liberation; rather than for the final recovery process and by utilising a high mass pull, high recovery process route (gravity/flotation), a narrow, low head, compact processing plant was developed that can sensibly be operated underground. The Python underground processing plant can provide a number of advantages for narrow vein mines including lower haulage costs, improved mine call factor and lower operating costs. The focus on fine crushing reduces the power requirement of the plant to approximately 8 kWh/tonne. The Python underground processing plant has been designed to be towed down the decline or lowered down a shaft, and is capable of being installed in sloping, non-linear drives for placement close to the working face. The overall benefit to mining companies of this concept has been estimated to be a saving in mining costs and a significantly smaller environmental footprint.

Jan 1, 2008

By M R. Lane, M L. Cramer, N P. Wines

Increasing attention is being focused by regulators and industry on the residual environmental liabilities associated with mining projects following site relinquishment (termed surrender in Queensland). Even sites that have been rehabilitated to a high standard and to the satisfaction of the regulator are not completely risk free and may require some degree of ongoing management. As well as ongoing monitoring and maintenance costs, considerations should include how costs associated with potential risk event occurrence can be quantified and, if considered material, how provisioning should be undertaken to minimise the risk to the state and to taxpayers. In Queensland for example, once a resource site is fully rehabilitated and meets its environmental authority conditions or rehabilitation completion criteria, the tenure and environmental authority can be surrendered. During the surrender process any ‘residual risks’ resulting from the use of the site for the resource activity must be considered, and, if requested, a payment given to the government to cover any ongoing management and risk costs. Accent Environmental, in conjunction with Lane Associates, was engaged by the Queensland Government as part of the government’s financial assurance framework reforms to develop an innovative, ‘one-size fits most’ Residual Risk Calculator for the Queensland resources industry. The calculator is an Excel-based tool that uses detailed user inputs to estimate post-surrender management requirements and liability at resource sites. If residual environmental risks associated with rehabilitated mine sites can be identified, quantified and managed through pragmatic regulatory tools and effective provisioning, site relinquishment/surrender can be achieved without compromising environmental and social outcomes or exposing the state to unreasonable financial risk. The effective management of residual risk can also help facilitate operations as well as relinquishment/surrender of sites where a ‘walkaway’ solution may not be otherwise technically feasible.

Aug 2, 2023

By J Franke, C Gonzalez

One of the regular tasks of geotechnical and mining engineers is the measurement and management of deformation in underground excavations. Although several methods are used to do so, the incumbent methodologies for monitoring deformation and ground support serviceability are limited to the use of visual observations or measurements at discrete points, resulting in a qualitative assessment only. The introduction of LiDAR technology allows a quantitative assessment across the entire excavation volume and its rock surface, by collecting a full three-dimensional image of the entirety of an excavation such as an underground drive, decline, or a tunnel. Comparisons between epochs of complete 3D data coverage allows for change detection over time that doesn’t feature otherwise typical omissions. The implementation of regular scanning has shown to be highly advantageous for mines with swelling or squeezing ground, but also at mines with rapid deformation. Despite the LiDAR potential, its adoption has been slow. A key reason for that is that working with point clouds is foreign to most geotechnical engineers. Point clouds have long been the realm of surveyors, but to fully adopt their use in geomechanics requires retraining, upskilling, and devotion by the individuals and the company. Sites are already stretched, so often there are insufficient resources to be applied to bringing the new technology into use. The solution to this hurdle is to partner with subject matter experts to achieve the desired high-quality outcomes without the commitment of time by geotechnical personnel. This paper presents a new solution of fully automated raw LiDAR point cloud data processing that not only enables geotechnical engineers to avoid having to learn unrelated skills by allowing for deformation monitoring without associated training or expertise, but it also provides instant reporting results as well as a sophisticated database with features otherwise not available. All data processing time and effort is completely replaced by an automated process which at the same time opens up the opportunity to monitor many more excavation volumes at a higher frequency than is possible with conventional tools and methodology.

Nov 29, 2022

By J Durbin

To effectively plan for closure, we must have an end-point in mind. To undertake meaningful rehabilitation, a post-mine land use (or uses) must be known. However, it is becoming more apparent that the end-point or “goal-posts” are shifting - and may continue to do so throughout the life of a mine. As well as being safe, stable and not causing environmental harm, post-mine land uses should always be sustainable, achievable within the given land capability, and they should involve stakeholders in their design and development.The majority of mines in Australia, and around the World, were historically expected to return disturbed land to either native ecosystem or agriculture/forestry practices. However, examples of highly successful final land uses suggest that today’s focus on closure includes not only minimising future liability and impact but also – and importantly – a move towards the creation of economic opportunity (Murphy and Heyes, 2016).CITATION:Durbin, J, 2018. Planning for (not so) final land use, in Proceedings Life-of-Mine 2018, pp 110–112 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By P B. Swart, P D. Erskine

Despite an increasing focus by media, communities and activists driving an elevated regulatory focus in Australia and indeed some other mining jurisdictions, the mining industry globally has had limited successful mine lease relinquishments and transfers to support a next land use.Critique from anti-mining lobbyists frequently uses the large estimates from historically abandoned mine sites to influence risk-averse regulatory reforms to improve environmental performance. The mine rehabilitation regulatory processes in Australia, and specifically in the State of Queensland, are thus largely in place to prevent mining operators from abandoning their obligations.Regulatory responses to the lack of mine rehabilitation and closure performance in the last five to ten years have primarily focussed on compliance and enforcement of rehabilitation conditions in environmental approvals. Additionally, financial assurance measures have been tightened to protect against abandonment of rehabilitation obligations by the Industry, including the Chain of Responsibility legislation (Queensland Government, 2016b) in April 2016, to hold to account those who have benefitted from mining and processing/refining projects, and then avoid their environmental obligations.CITATION:Swart, P B and Erskine, P D, 2018. Are our closure planning and regulatory processes adequate to identify, quantify and appropriately transfer residual risks after successful mine rehabilitation?, in Proceedings Life-of-Mine 2018, pp 155–158 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By J L. Merritt

Contour banks and waterways are standard soil conservation measures to assist farmers reduce the impact of gully erosion on sloping cropping land by reducing the slope length to the interval between the banks. The Universal Soil Loss Equation (USLE) developed by the USA Department of Agriculture Soil Conservation Service in 1930s predicts the long-term average annual soil loss (A).The equation is the product of the rainfall erosivity factor (R), the soil erodibility factor (K), the topographic factors of slope length and angle (L and S) and the cropping management factors (C and P). Contour banks reduce the slope length (L) only.Contour banks are a constructed earth embankment, incorporating a channel on the upslope side, typically traversing a slope on or close to the contour to control and/or prevent the erosion of that slope. The banks are also referred to as graded banks, terraces, or bunds (DSITI 2015). Contour banks are either broad based or narrow based. Broad based banks allow the passage of the machinery over the banks whilst narrow based bank batters are too steep preventing the passage of machinery. Waterways are a stable, longitudinally sloping water disposal area of sufficient capacity used to discharge surplus runoff from the contour bank and to allow it to flow to a lower level without causing erosion (DSITI 2015).The mining industry must decide what the role for contour banks and waterways is in each operation’s rehabilitation and closure plan.CITATION:Merritt, J L, 2018. Contour banks in spoil rehabilitation – a matter of timing, in Proceedings Life-of-Mine 2018, pp 147–149 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By R L. Grogan

Regulators of deep-sea mining projects are becoming increasingly hesitant about the concept of adaptive management as a tool to facilitate compliance and continuous improvement. Adaptive management is a relevant and useful instrument to ensure that the mine plan is successfully implemented throughout the life of mine, in parallel with optimum environmental performance and compliance.CITATION:Grogan, R L, 2018. Adaptive management in deep sea mining – looking like you know what you’re doing when it’s never been done before, in Proceedings Life-of-Mine 2018, pp 20–22 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

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 N Boughen, K Moffat, L Brooks, A Zhang

In 2015, Ernst and Young (EY) ranked socio-political license to operate (SPLTO) as the fifth greatest challenge to the mining sector (EY, 2015). The EY report asserts that SPLTO will continue to present a risk to the mining sector in the context of ‘increased activism, digitally connected stakeholders and politicians who need to respond to general consensus’. While there is no consensus on a definition, SPLTO is commonly regarded as the ongoing acceptance or approval of an operation by affected stakeholders (Moffat and Zhang, 2014; Thomson and Joyce, 2008) as well as those stakeholders that can affect the operation (Graafland, 2002). Warhurst (2001) relates the process of stakeholders granting SPLTO to the establishment of meaningful partnerships between operations, communities and government based on a variety of factors that build trust between stakeholders.From these accounts, we can see that understanding stakeholder attitudes about company performance and impacts on stakeholders directly affected by an operation are important in any attempts to measure SPLTO. Understanding the level of acceptance of an operation within these stakeholders provides a good proxy or outcome measure of SPLTO. Moreover, trust seems to be a central variable in the translation of these experiences of an operation into acceptance. What the mine or company does, its behaviour, degrades or builds trust with stakeholders, and this then affects acceptance (Moffat and Zhang, 2014).In addition, a strong emphasis is placed on the nature of the relationship between companies and stakeholders as influenced by inter-group interactions. It is not just what companies do well or poorly with respect to environmental impacts, for example, that will determine trust and acceptance, but how the company relates to its stakeholders at personal and group levels.These relationships between communities of stakeholders and extractive companies are dynamic. Brown and Fraser (2006) recognised the importance of industry being able to respond to the changing nature of societal approval and acceptance, arguing that ‘business must have regard for evolving social attitudes and expectations if it is to maintain its ‘social licence’’.This paper will describe a series of five pilot projects conducted by CSIRO with Anglo American in Australia and South Africa to generate a real-time understanding of SPLTO to guide more reflexive and effective social performance strategies.CITATION:Moffat, K, Boughen, N, Brooks, L and Zhang, A, 2016. Social licence in real-time – using dynamic methods to support a new kind of community relationship, in Proceedings Life-of-Mine 2016 Conference, pp 191–194 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By D L. Head

Critical risk management (CRM) has become one of the latest safety buzz terms in mining. Everyone seems to be doing it, everyone seems to know about it, yet we are still having fatalities in our industry from well understood hazards such as mobile equipment amongst others.

May 5, 2022

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