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By P Clark, P A. Kirsch, R Tapia Rivera

Community members’ sources of information about companies’ social investments are often influenced by the messages in a variety of communication channels, such as newspapers, television and social media. In this sea of communication channels, corporate communications may not always have the desired effect in influencing community perceptions. This paper explores the efficacy of communication between mining companies and communities in Chile through content analysis of corporate sustainability reports and newspaper reporting.Chilean media reporting between 2005 and 2013 is examined to identify community perceptions of corporate social investments made by mining companies. Content within the Chilean newspapers El Mercurio (national) and Soy Chile (regional) is contrasted with content from corporate sustainability reports published by The National Copper Corporation of Chile (Codelco) and Barrick Gold Corporation, Canada (Barrick) for the same period. The objective is to identify differences in the way that corporate social investments are reported by companies in sustainable development reporting and by media in newspapers.Overall, the study demonstrates that the media’s framing and reporting of corporate activities was more negative than positive. Moreover, media outlets tended to focus upon the ‘negative impacts’ or ‘damage’ to communities brought about by mining developments. Conversely, companies’ public communications were largely focused upon direct improvements in livelihoods (health, education, etc) of neighbouring communities. This preliminary study provides a baseline for the development of new formats of effective communication with neighbouring communities. The paper advocates for an increase in participatory mechanisms with affected parties, which could lead towards a greater mutual understanding of the impacts and draw parties closer together.CITATION:Tapia Rivera, R, Kirsch, P A and Clark, P, 2014. Challenging Perceptions? Sustainability Reporting, the Media and Mining, in Proceedings Life-of-Mine 2014 , pp 413–426 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By T Baumgartl, C Gonzales, A Soliman, M Edraki

A soil cover isolates potentially acid-forming (PAF) mine wastes from atmospheric interaction and thereby mitigates acid mine drainage. As a cover that comprises either a single layer or a composite barrier, it essentially manages percolating rain water from flowing into these PAF materials and minimises air flow as oxygen has low diffusivity in saturated soils. However, the availability of suitable soils as cover materials is limited, especially in arid and semi-arid regions where weathering rates are low.This paper investigates the potential use of mine wastes as cover materials in a water-shedding soil cover in north-west Queensland. Four cover trial plots were built using mine wastes as cover materials. Each 2.3 m cover trial plot consisted of a 1.5 m soil cover made up of waste rocks and fines, a 0.5 m drainage layer that consisted of 0.1 m waste rock aggregates and a base layer made up of blended mine tailings. The hydrologic properties of cover materials were determined by in situ measurements and laboratory experiments, which, in turn, were used as input in a numerical model that described the cover’s transient soil moisture profile. The successful performance of the cover is reliant on the long-term stable geochemical behaviour of the substrate used as cover material. Therefore, investigations were carried out to determine the geochemical properties of the cover materials constructed from benign waste rock using static and kinetic tests, with the objective to increase the level of certainty of the material’s benign characteristics. Consequently, the long-term performance of this water-shedding cover design is described in terms of the physico-chemical characteristics of its outflows.CITATION:Gonzales, C, Baumgartl, T, Edraki, M and Soliman, A, ?2014. Mine wastes as cover materials in a water-shedding soil cover in north-west Queensland, in Proceedings Life-of-Mine 2014 , pp 261–270 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By P Audet, D Doley

The mining industry often embraces mine closure criteria that require the reinstatement of predisturbance or even presettlement (ie historic) ecosystems. However, the extent and severity of disturbance associated with most mining activities mean that critical physical and biological characteristics are irreversibly altered. Consequently, it is rare that a reconstructed landscape can support ecosystems even close to the historic condition, and this rarity is reflected in the small number of mine leases that have been extinguished by attainment of such completion criteria. Novel ecosystems are defined as those in which some or all physical and biotic components are irreversibly different from the historic condition. Recognition of the concept of novel ecosystems allows mine closure criteria to be set according to attainable physical and biological conditions that provide safe, stable and manageable environments with acceptable ecological functions. We propose that a landscape that first maximises physical stability and economy yet will provide a range of environments for vegetation communities and fauna habitats that may be very different from those existing prior to a disturbance should be considered suitable alternatives to, eg targeting idealised historic environments. As a result, mine closure criteria should be established by detailed description of the best attainable physical conditions, with negotiated identification and testing of the most appropriate biological systems for the various parts of the reconstructed landscape. As a general practice, revegetation would use native, but not necessarily local species if the new physical environment is not conducive to the survival and growth of local species. These new ecosystems would need to be managed in perpetuity, although the intensity of management might be low if landscape design and engineering are combined with appropriate species introductions. Here, we suggest an abbreviated procedure that may be adapted in light of local conditions and circumstances for guiding decisions influencing the physical and biological properties of reconstructed landscapes that will enable novel ecosystems to meet realistic closure criteria.CITATION:Doley, D and Audet, P, 2014. Changing restoration priorities in the 21st century – opportunities for novel ecosystem design in mine closure, in Proceedings Life-of-Mine 2014 , pp 649–662 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By M Gasparon, J Harris, T Baumgartl, D J. Williams, M Edraki, P A. Kirsch, D Rowe

RISKGATE, an Australian Coal Association Research Program-funded (ACARP) initiative, has been designed to assist the Australian coal mining industry in improving minimum standards for safety performance, efficiency, operating practice and training. The online system is innovative in that it is built upon a foundation of industry expert knowledge gathered through action research workshops, which is further supported by a broad array of industry, academic and technical resources. In operation, RISKGATE offers a continuum for knowledge transfer and communication of current practice in risk identification, assessment and management in the coal mining industry. The primary mission of RISKGATE is to focus industry attention on prioritising control management as a way to achieve acceptable risk.A Coal Mine Tailings Dam Module has recently been added to the RISKGATE suite. The key risk, or initiating event, associated with coalmine tailings dams is catastrophic failure of the dam, leading to the release of tailings and water. This can occur due to geotechnical instability of the dam itself or of its foundation, overtopping and erosion of the dam, and piping failure of the dam itself or of its foundation. Coalmine tailings dams are also prone to seepage into the foundation and through the dam, particularly during operation when large volumes of water are discharged with the tailings. The most significant risk associated with seepage is the release of potentially contaminated water to the environment. Contamination can take the form of elevated salinity, acidity and dissolved metals. Run-off from coalmine tailings can cause erosion and can also potentially contain contaminants. Desiccation of the tailings surface can result in dust generation and dispersion.The paper presents the background and context of the RISKGATE project, the need for the addition of the RISKGATE Coal Mine Tailings Dam Module, and a description of the developed module, including the five initiating events considered, their causes and associated preventive controls, and their consequences and associated mitigating controls. This paper concludes with a discussion of the ways in which Australia’s coal mining companies are starting to apply the RISKGATE body of knowledge at their sites, which will flow onto the management of their tailings dams.CITATION:Williams, D J, Kirsch, P A, Gasparon, M, Baumgartl, T, Edraki, M, Rowe, D and Harris, J, ?2014. Application of RISKGATE to coal mine tailings dams, in Proceedings Life-of-Mine 2014 , pp 219–230 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By G Hancock, J Lowry, T Coulthard, W Erskine, M Saynor

An important part of planning for the rehabilitation of uranium mine sites is the ability to assess the geomorphic stability of the final landform, over time frames ranging from decades to millenia. Depending on the environmental conditions, erosion features such as gullies may incise into containment structures, potentially leading to the exposure and transport of encapsulated radioactive material. Further, erosion may lead to increased sediment loads and the transport of other mine-related contaminants off-site and into downstream waterways. While erosion may be monitored and assessed over the short term (years to decades), the longer-term behaviour (centuries to millennia) of such landscapes is not within any meaningful human management time frame. Landscape evolution models (LEMs) can provide information on soil erosion rates at decadal or centennial scales over large spatial scales, and evaluate the sensitivity of these processes to environmental changes. However, an important issue associated with the use of models is the ability to assess the reliability and accuracy of the model. In this paper, the CAESAR-Lisflood LEM is tested for its ability to predict soil erosion from a series of 30 m × 30 m experimental plots specifically constructed for this purpose on a trial rehabilitated landform at the Ranger Uranium Mine in the Northern Territory, Australia. Model predictions of bedload and suspended sediment loads from the erosion plots were compared with field measured observations collected over four wet seasons from the trial landform. Once calibrated for the specific site hydrological conditions, the predicted sediment yield – specifically, bedload – demonstrated an excellent correspondence with the field data. However, longer-term simulations of ten years identified an exhaustion effect in sediment yield from the landform. These latter results indicate that a weathering function needs to be incorporated into CAESAR-Lisflood to ensure confidence that the CAESAR-Lisflood LEM will be able to correctly predict the long-term evolution of a rehabilitated landform once it has been?constructed.CITATION:Lowry, J,?Saynor, M,?Erskine, W, Coulthard, T and Hancock, G, 2014. A multi-year assessment of landform evolution model predictions for a trial rehabilitated landform, in Proceedings Life-of-Mine 2014 , pp 67–80 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By M Berry

Consider these four questions:What is the definition of life-of-mine?When should life-of-mine planning seriously commence?When can life-of-mine planning seriously commence?What is the key input to effective life-of-mine planning?Whilst there is likely to be general consensus on the answers to the first three questions, the answer to the fourth question is open to debate. This author argues that understanding and managing risks and opportunities associated with geological uncertainty is the key input to effective life-of-mine planning, at all stages in the life cycle of a mining project.CITATION:Berry, M, ?2014. Effective life-of-mine planning by understanding and managing risks and opportunities associated with geological uncertainty, in Proceedings Life-of-Mine 2014 , pp 183–190 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By D Weatherley, T Baumgartl, L Huang, Q Shao

The stabilities of rehabilitated landforms are often threatened by the altered surface hydrology, especially the excessive surface run-off, which may cause severe water erosion and associated pollutant transport to surrounding areas. These effects would lead to pollution in waterways and render the failure of newly established vegetation. An accurate quantitative evaluation of run-off problems are consequently essential for the proper rehabilitation designs which can help minimise these harmful consequences. For this purpose, in this study a novel run-off model, RunCA, was developed based on Cellular Automata (CA), integrating fundamental hydraulic principles. In this model, a series of rectangular cells were employed to cover the study area. Run-off production within each cell was simulated by determining the cell state (water surface elevation) that consists of both cell altitude and water depth. The distribution of water flow among cells was determined by applying CA transition rules based on the improved minimisation-of-difference algorithm and the calculated flow travelling time. RunCA was applied to various aspects in mined land rehabilitation planning, including landform designs for both hill-slopes and tailings dams, revegetation strategies and cover constructions. Simulation results showed that surface run-off increased with slope gradient and more run-off was produced on convex and straight slopes than on concave and S-shape slopes. Both mounds and rip lines constructed on the tailings dam surface could help reduce the water discharge. Vegetation planted in rows were more effective than those in columns or patches in controlling run-off. Increased cover thickness had the potential in reducing run-off rates, and the covers with an increasing thickness from top to bottom of the slope tended to be more efficient than those with a constant thickness. All these results have demonstrated the efficacy of RunCA as a simulation tool in assessing the hydrologic behaviours of different rehabilitation designs. Compared to the traditional hydrologic models, most of which were developed for the catchment scale studies, RunCA has the potential advantages in capturing the dynamic and spatially varied run-off behaviours at different spatial and temporal scales.CITATION:Shao, Q,?Baumgartl, T, Huang, L and Weatherley, D, 2014. A cellular automata-based run-off model and its application in mined land rehabilitation designs, in Proceedings Life-of-Mine 2014 , pp 81–96 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By H Sichani-Teimouri, B N. Noller, J C. Ng, R N. Alsaadi, P L. Breuer, S Shini

Cyanide has been used for over a century worldwide for gold extraction. However, the presence of several metals and metalloids in ore requires greater amount of cyanide for an efficient gold recovery due to their solubilisation in conjunction with gold. The extraction residues are discharged into tailing storage facilities (TSFs) and may cause bird mortality if there is exposure to cyanide-bearing wastewater exceeding the toxic threshold. The toxicity arises from free cyanide released from weak acid dissociable (WAD) cyanide complexes. The International Cyanide Management Code (ICMC) has deemed 50 mg/L of WAD cyanide released into TSFs to be safe for wildlife protection. However, this concentration is based on observations of an apparent lack of toxicity rather than a toxicological approach. The National Industrial Chemicals Notification and Assessment Scheme (NICNAS) identified in 2010 that there is a lack of toxicity data to properly assess the environmental significance of cyanide levels at gold mines. Lack of knowledge for the toxicity of free cyanide and metal cyanide complexes to wildlife led to consider alternative direct assessment techniques for designating safe levels. Whilst toxicity may be assessed by using young chickens with animal ethics approval, the traditional bioassay approach to assess cyanide toxicity is impractical for gold mine TSFs. Bioassays using algal species such as Euglena gracilis, a unicellular alga, are widely used for ecotoxicological studies. A unique feature is that the Euglena gracilis Z cell has plant-like while SMZ cell has animal-like characteristics. The aims of this project are to evaluate the suitability of Euglena gracilis Z and SMZ strains to assess the toxicity of free cyanide and both strong (cobalt) and weak (zinc, copper and nickel) acid dissociable metal-cyanide complexes that may be present in TSFs.CITATION:Noller, B N, Ng, J C, Shini, S, Breuer, P L, Sichani-Teimouri, H and Alsaadi, R N, 2014. Development of a toxicity approach to evaluate free cyanide and metal cyanide complexes in waters associated with gold and other mining, in Proceedings Life-of-Mine 2014 , pp 573–590 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By J Skousen, C E. Zipper

"Prior to the 1950s in the USA, surface coalmines were generally left without any reclamation. As government regulations advanced, mine operators were required to backfill the area and plant grasses or trees. After the federal Surface Mining Control and Reclamation Act (SMCRA) was passed in 1977 in the USA, mine operators were required to conduct pre-mining analyses of the site and to designate a land use that could be achieved after the mining. Common post-mining land uses in the USA are: agricultural uses such as prime farmland reclamation with crops, hayland and pasture, and biofuel crops forestry wildlife habitat building site development.Provisions and regulations for each post-mining land use were developed and practices to achieve successful and sustainable land uses were established. Post-mining conditions should provide ecosystem services and produce lands capable of supporting societal needs in the future.CITATION:Skousen, J and Zipper, C?E,?2014. Post-mining land use options in the Appalachian coal mining region of the USA, in Proceedings Life-of-Mine 2014, pp 153–164 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 16, 2014

By R L. Chaney, M Mahoney

Mine and ore beneficiation wastes and smelter contaminated soils often cause phytotoxicity and threaten adverse environmental effects if not remediated. Science has clarified both the risks from soil metals and methods to alleviate those risks that can be applied at low cost. Phytoremediation is a family of plant and agronomy based technologies to deal with environmental aspects of sites requiring remediation. If valid risk assessment indicates that metals comprise risk, phytostabilisation may be used to alleviate that risk for most contaminated sites. In particular, Zn-Pb, Cu and Ni mine and smelter sites are readily remediated by making the soil calcareous and fertile, with added organic and metal sorbent amendments that include soil microbes to ‘revitalise’ the soil. In each case, the soil fertility and causes of phytotoxicity should be clarified by agricultural soil extractions, and the combination of amendments required to improve fertility and reverse phytotoxicity identified and found locally. In contrast with phytostabilisation, phytoextraction/phytomining uses rare metal hyperaccumulator plants and agronomic management to maximise annual phytoextraction of soil elements into plant shoots for harvest, ashing and use as a metal ore. Plants that accumulate more than two per cent Ni in shoots, and yield 10–20 t ha-1 dry biomass yield 200–400 kg Ni ha-1, which has value greater than all common agricultural crops. Considering the value of elements, existence of hyperaccumulator plants and demonstrated agronomic management for Ni phytomining, it is clear that mine sites and Ni mineralised subore-grade serpentine soils can be phytomined economically as an agricultural mining technology. A team developed agronomic methods and improved cultivars of Alyssum, which can be profitably grown on temperate zone Ni mineralised or contaminated soils. Plant species for tropical ultramafic soil materials have been identified. Phytoextraction is also strongly needed to remove Cd from rice soils to prevent human disease from soil Cd.CITATION:Chaney, R?L?and?Mahoney, M, 2014. Phytostabilisation and phytomining – principles and successes, in Proceedings Life-of-Mine 2014 , pp 3–16 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By J J. Robinson, B N. Noller, D M. Franks, G McIlveen, D R. Mulligan, A T. Soro

Fiji is a developing nation that relies on economic opportunities and recently experienced increased interest in mining and mineral exploration that could potentially benefit the country. In order to understand the lack of, or failure of, past rehabilitation activity, this study applied risk-based approaches to identify the significance of activities or actions applicable to rehabilitation of post-mined land in Fiji. This involved the use of qualitative, semi-quantitative and quantitative risk methodologies, which allow assessment and evaluation of mechanisms of mining administration and practices, as well as rehabilitation methods and approaches that have been applied successfully to post-mined land in other countries with similar environmental and climatic conditions and social and regulatory environments to Fiji. The semi-quantitative risk-based technique followed an earlier approach applied for mine closure by Laurence (2006) and provided a systematic way to assess and evaluate rehabilitation issues that were identified on-site by assessors, who were able to estimate through expert judgement the likelihood and consequences based on conditions, situations observed and circumstances on-site. It demonstrated that experienced professionals could reproducibly score likelihood and consequence of selected items relevant to mine site rehabilitation, despite the wide-ranging issues identified during post mined land rehabilitation. The quantitative risk-based approach was adopted as a method to determine environmental bonds for mining projects using the assessment of consequences and likelihood results from the semi-quantitative approach, then incorporating unit cost of materials or activities for local conditions required to fully rehabilitate each issue at net present value. Application to both an abandoned mine site and a newly opened mine site in Fiji showed that this approach could provide a risk-based estimate for rehabilitation cost and demonstrated potential applicable in the Fijian context.CITATION:Soro, A T, Mulligan, D R, McIlveen, G, Franks, D M, Robinson, J J and Noller, B N, ?2014. Risk-based Rehabilitation Strategies for Post-mined Land in Fiji, in Proceedings Life-of-Mine 2014 , pp 165–180 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By P G. Doig

Recent drops in commodity prices and economic uncertainty have seen many businesses re-evaluate their operational expenditure to ensure mine profitability. The high capital and operational cost of truck and digger fleets has resulted in loading and hauling of material being a significant proportion of a mine’s expenses (Nel, Kizil and Knights, 2011), thus it is often one of the first areas to be considered for cost reduction. If an operation requires additional trucks to maintain or improve productivity, a robust justification is crucial due to the expenditure involved.Mining schedules form the basis of productivity and cost estimations for mining operations and therefore must have a significant level of confidence with regards to achievable quantities and rates. Traditionally, a mining schedule is produced without detailed consideration of the trucking capacity or requirements. Although some mine planning software incorporates haulage predictions into schedules, most cannot model the dynamic nature of dumping and haulage. Previous studies have shown that it is necessary to have detailed haulage analysis instead of the traditional mining block centroid to dump block centroid methods for more realistic mining schedules and cost estimation (Doig and Kizil, 2013).Recent developments in software have allowed the dynamic integration of haulage analysis with mining schedules. Engineers can now create mining schedules in conjunction with dumping schedules, allowing mining schedules to reflect the restrictions created by the number of available trucks, combined with dynamic consideration of available in-pit and out-of-pit dumping locations.A study has been completed producing a mining schedule in conjunction with a dumping schedule and haulage analysis. Multiple schedules were run with various haulage strategies (including minimising rehabilitation liability) and truck availability to identify the impacts on coal production, and hence revenue. A financial analysis was then completed where a net present value (NPV) was calculated for each scenario. The study showed that trucking shortfalls can significantly impact mining schedules and cost estimations, both in terms of cost as well as revenue lost when trucks cannot maintain forecast production rates, thus dumping schedules and haulage analysis should be completed simultaneously. If dumping and haulage is not considered when planning the mining schedule, a mining business is ignorant to the impacts trucking has on the mine production, closure risk and profitability.CITATION:Doig, P G, 2014. Value impacts of truck limited scheduling, in Proceedings Life-of-Mine 2014 , pp 513–524 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By S Worden, P A. Kirsch, A Kirsch

Despite the current downturn, coal remains an important commodity in the Australian economy. Increasing coal resource development has resulted in increasing competition for land use in coal mining regions across the country with communities and other stakeholders becoming more adept at articulating their concerns regarding this competition in a range of traditional and social forms of media. In this environment, obtaining and maintaining a social licence to operate (SLO) is problematic and has been identified as the fourth greatest risk facing the international mining industry.This research presents the findings from a longitudinal study on how Australian newspapers frame the views of coal mining stakeholders across each stage of the coal mining life cycle. News stories from national, state and regional newspapers in 2000, 2006 and 2013 were analysed.Over the study period, there have been significant changes in the coal mining themes being covered by Australian newspapers, the number of stories being published, the number of newspapers covering coal mining stories, and the diversity of stakeholders being quoted. How do the dominant themes in media communication change over time? How do these changes impact mining across the life-of-mine?The research confirmed that Australian journalists use framing, priming, labels and bias to conceptualise and understand the events that they report, and that this behaviour has a profound effect on public opinion.CITATION:Worden, S, Kirsch, A and Kirsch, P A, ?2014. Moving beyond economic framing of the Australian coal industry, in Proceedings Life-of-Mine 2014 , pp 365–376 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By L Dyer, A Keith, G D. Corder

As mining activity moves to remote and less developed locations globally, a holistic approach to mine development is fundamental for achieving a balance between strong financial returns and corporate social responsibility and transparency. Key inter-related fundamentals such as social licence to operate, life-of-mine operational planning, minimising environmental impacts and, most importantly, attractive investment returns for the mining company all contribute to the viability of any new mining project.However, the typical practice in the mining industry is often to treat environmental and social/community aspects as separate compliance issues that are dealt with at minimum cost and disruption to the project and resulting operation. This often results in less than optimum environmental and social outcomes, and presents considerable liabilities at the time of closure when rehabilitation programs continue to require funding when all revenue has ceased.The five capitals model seeks to identify each of the key contributors to sustainable development as financial, manufactured/physical, social, human and natural to formulate a type of triple bottom line approach balancing these often competing project factors. The SUSOP® sustainability risks and opportunities framework, developed by the mining industry, bases its approach on the five capitals model and proposes an approach that breaks down enterprise silos to identify innovative solutions for life-of-mine sustainability. This framework has been developed with the nature of mining projects in mind in order to produce approaches and outcomes relevant throughout the life cycle from the planning phases, through project design and construction into operation and closure.This paper argues the need for a more holistic approach to the development and operation of mining projects, and presents case studies where a holistic approach has been applied, in whole or part, and discusses the lessons learned from these case studies.CITATION:Corder, G D, Keith, A and Dyer, L, 2014. A capitals based approach – leading innovation in planning for life-of-mine sustainability, in Proceedings Life-of-Mine 2014, pp 499–512 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By M C. Evans

"Mine decommissioning is the final phase in a mining project. Planning for decommissioning must commence for a proposed mine even before the government approves it. Queensland mining approvals require proponents to commit to completion (or closure) criteria defining successful rehabilitation. Queensland mining project statutory environmental authorities must also specify how progressive rehabilitation is to occur throughout the mining project. Final landforms with graded banks together with creek and run-off diversions are often required and constructed early in the life of a mining project. At closure, mining projects must demonstrate that future medium-term risks are not significant, or failing this, a residual risk financial payment must be made to the state. CSIRO climate change projections indicate that Queensland is likely to become warmer this century with less rainfall in parts and with extreme rainfall events likely to occur more frequently. This project was undertaken to?determine: if current rehabilitation planning tools assist in determining the environmental risks from mining closure not adequately addressing climate change if these risks are addressed by current rehabilitation outcomes.The north-west Queensland mining region and the central Queensland coalfields were represented in this project by five study sites. Local data sets for temperature, rainfall and rainfall intensity were produced using conservative greenhouse gas emission scenarios representing likely future atmospheres, and using the SimCLIM climate model, Evaporation data sets were also derived from available climate parameters. These projected climate variables supported equations and models used in Queensland to determine mining project rehabilitation completion criteria. Storm intensities and return intervals were directly applied to assess the likelihood of failure of engineered structures such as stormwater diversions and banks. Plant cover change determined by an existing growth model together with rainfall intensity and changes in the R and C factors of the universal soil loss equation (USLE) erosion model enabled estimates of long-term erosion rates. Flood estimates were undertaken using regional rated catchments.The study found that stormwater diversions and banks on recontoured rehabilitated landforms, if constructed to currently accepted completion criteria, would likely fail within 30 years and with the likelihood of failure steadily increasing thereafter. The change in likelihood of failure was able to be estimated and could be applied to the determination of residual environmental risk for approval of a surrender application involving rehabilitation. The USLE model showed that long-term erosion rates increased as a consequence of climate change from north to south across the Queensland mining precincts. Because the growth model did not consider carbon dioxide fertilisation affects, results would likely be worse-case.Likely climate change outcomes have consequential residual environmental risks of mining project rehabilitation failure. This increased risk may result in increased payments to the state from mining projects where high consequences exist. The liability to the state and risk to the environment can be avoided if today’s completion criteria address tomorrow’s climate change impacts.CITATION:Evans, M C, 2014. Queensland mines should consider climate change impacts for decommissioning, in Proceedings Life-of-Mine 2014, pp 535–562 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 16, 2014

By B Howard, M Jones, D Pershke

"Current closure objectives and criteria are often difficult to achieve and are not delivering value for money outcomes at closure. Current mine closure processes tend to focus on rehabilitation and revegetation of landform structures to as close to premining condition as possible, rather than focusing on the functions of those structures and values they provided. Because mining has highly disturbed the environment, premining conditions and vegetation are often not achievable and objectives and criteria aimed at achieving close to these conditions have been shown to be very costly.The authors have developed a broader approach to developing mine closure plans that is based on environmental risk and gaining post-closure social, environmental and economic value. We think the focus should shift from trying to return the original landscape to returning functions and values provided on- and off-site. If it is not possible to return values on-site in a cost-effective manner, investment should be provided to deliver equivalent values elsewhere.This process can provide better stakeholder acceptance, deliver better environmental outcomes on the tenement and within the catchment and significantly reduce costs, whist fulfilling closure obligations.This framework should enable closure teams to: focus on the functions and services that are important to achieve as outcomes post-closure, rather than a focus on revegetation and replacing the premining biophysical structure engage meaningfully with stakeholders regarding closure outcomes and link outcomes to stakeholder values conduct transparent option evaluations that enable stakeholders to clearly understand the costs and benefits associated with each option and to participate in dialogue on option selection.We present examples of how the framework could be applied to identify alternate closure options that achieve equivalent value outcomes while reducing the costs of closing the mines.CITATION:Howard, B, Pershke, D and Jones, M, 2014. Achieving better mine closure outcomes for less money, in Proceedings Life-of-Mine 2014, pp 615–620 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 16, 2014

By B W. Ham

The legacy of underground coal mining may be a land surface which, in parts, may be unstable in the long term. A case study analysis has been undertaken to explain some of the hazards and how the risk may be assessed and managed.The Ipswich Coal Measures were extensively mined with shallow underground workings, which now underlie a number of suburbs in the eastern side of the city of Ipswich in south eastern Queensland. The area was subject to underground mining from the 1840s to 1997. In general, the mines were small, family-owned operations that were restricted by complex geology, interactions with neighbouring operations and ownership of surface facilities. The oldest available mine plans date back to the late 1890s.The residents in these mining areas have a long history of unexpected mining subsidence events. A level of risk management for property owners has been implemented by the Ipswich City Council, which requires a mining subsidence risk assessment to be submitted as part of building applications for property development in the areas suspected of having mining subsidence risk. This discussion examines a series of generic subsidence events and how the risk may be assessed and managed and the hazard controlled.CITATION:Ham, B?W, 2014. The legacy of underground coal mining – mine subsidence: Ipswich coal measures case study, in Proceedings Life-of-Mine 2014 , pp 113–120 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By M Ind, B Usher

Environmental regulators are increasingly adopting risk-based approaches to protect aquatic ecosystems. The Australian and New Zealand Environment and Conservation Council (ANZECC) and the Agriculture and Resource Management Council of Australia and New Zealand (ARMCANZ) (2000) introduced a risk-based approach to water quality guidelines that use decision frameworks to adapt water quality guidelines to local environmental conditions. Environmental quality objectives are no longer a simple ‘pass or fail’ number such as restricting total suspended solids (TSS) concentration to a specified limit for a particular rainfall event. This approach ignores spatial and temporal variability and the complexity of aquatic ecosystems. The risk-based approach establishes levels where adverse effects may occur. If these objectives are not met, further risk-based investigation is undertaken to assess the potential impact to the ecosystem. Klohn Crippen Berger (KCB) developed a dynamic simulation to predict the variability of sediment discharges, which is applicable for risk-based impact assessment of aquatic ecosystems. The application of the methodology over the life of a mine site is illustrated using a proposed South Pacific mine.The site location is in extremely rugged terrain with a high annual rainfall of approximately 4.7 m. There were two major sediment ponds proposed to reduce sediment discharges. A sediment and hydrology model was developed in Goldsim to provide daily estimates of run-off flows and sediment concentrations. A modified algorithm based on the Australian water balance model was created and incorporated into the Goldsim model and calibrated using recorded field data.The sediment module was developed based on a Revised Universal Soil Loss Equation (RUSLE) assessment, an annual prediction of soil loss over a catchment. A land-use type erosion vector was developed for different land-use types and for each of the subcatchments, a subcatchment erodibility vector was calculated. This vector and the daily rainfall erosivity factor were used to estimate the daily soil loss. The estimated soil loss and the modelled run-off yielded predictions of daily sediment concentrations. Finally, a sediment settling module was used to predict the daily efficiency of the sediment ponds and hence discharged sediment concentrations.The results of this modelling form the first part of a quantitative risk-based assessment into suspended solids impacts. The second part is the assessment of the effects of these predicted TSS concentrations on aquatic ecology. As part of the feedback-loop required in a risk management framework, if the environmental quality objectives are not met then further management decisions and actions may be required to reduce the risks presented by suspended solids. This may include modifications to: the mine-development plan; construction techniques and scheduling; processing techniques; rehabilitation strategies; or hard-engineering solutions such as sediment basins or flocculation.The Goldsim water-balance model provides a quick and efficient method of testing potential remedial actions on predicted sediment loads and concentrations. In combination with a cost-benefit assessment, options for reducing sediment releases from the mine site can be effectively and quantitatively compared thereby providing mine operators with a basis for decision-making. Regulators can also be satisfied that potential impacts to aquatic ecology have been comprehensively assessed and the necessary management decisions have been initiated to limit risk to the environment.CITATION:Ind, M and Usher, B, ?2014. A dynamic sediment simulation to predict the variability of suspended solids concentrations over life-of-mine for application to a risk-based environmental assessment, in Proceedings Life-of-Mine 2014 , pp 191–204 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By C Roche, G M. Mudd

The Morobe Province of central Papua New Guinea (PNG) has been mined for gold for nearly a century, although it is only in the past decade that large-scale modern mining commenced. The Hidden Valley gold-silver project began construction in mid-2006 and production by August 2009, and is located in the mountains above Wau in the headwaters of the Watut River. The mine is owned and operated by the Morobe Mining Joint Venture (MMJV), which also owns the Wafi-Golpu project, comprising the Wafi gold deposit and Golpu copper-gold deposit, situated in the Watut River Valley. Together they represent a potential mine of the scale of Ok Tedi or Bougainville or bigger. The MMJV is owned in equal shares by Newcrest Mining from Australia and Harmony Gold from South Africa. Although Hidden Valley was the first large-scale mine in PNG to engineer and build a tailings storage facility, poor environmental management during construction and early operations led to significant erosion of waste rock and sedimentation impacts throughout the ~200 km length of the Watut River. Since then, substantial efforts have been made to improve environmental management, especially waste rock placement and storage and water quality management. While the impacts from the Hidden Valley project appear to be reducing, the saga has heightened concerns by many along the Watut River and across PNG about ongoing impacts from mining.This paper presents the results of an ongoing project in the Morobe Province conducted by the Mineral Policy Institute examining the historical, current and future impacts of mining, including community views, social and environmental impacts and the monitoring and regulation of mining. Overall, there is a clear need to more fully integrate social and environmental issues into life-of-mine planning and go above and beyond regulatory requirements. In this way, some of the lessons learnt – by the community, MMJV and government – can be incorporated before, during and long after mining.CITATION:Mudd, G M and Roche, C, ?2014. Mining in Morobe, Papua New Guinea – impacts, assurance and self-determination, in Proceedings Life-of-Mine 2014 , pp 313–336 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By D Blair, T Scutts, L Fergusson

This paper presents a waste rock treatment and rehabilitation program conducted at a metaliferous mine site in northern New South Wales from 2000–2013. It updates findings from 2005 for Program #1 (which examined acidity, leachable metals and tree growth in a control and three treated areas of waste rock) and includes new results for Program #2 (which examined acidity, plant uptake of metals and trace elements and tree growth in a control and four treated areas compared to undisturbed background levels) and Program?#3 (which examined the treatment and revegetation of submerged mine tailings and an exposed tailings beach).Program #1 showed low soil pH in the control area remained unchanged from years 1–14, and soil pH in the limed and capped areas was initially increased but fell back to starting levels within 12 months and remained low for 14 years. In contrast, soil pH in the Terra B area resulted in soil high pH immediately after treatment and increased in years six and 14 without further treatment. Tree height and density in 2005 and again in 2013 indicated acidity in the control, limed and capped areas suppressed tree height and density; however, in the Terra B area, revegetation in 2013 was comparable to undisturbed forest. Outcomes in the control, biosolids and three Terra B areas in Program #2 were similar to those observed in Program #1.Program #3 showed the submerged and exposed tailings initially had low pH and high concentrations of total and leachable metals before treatment, but these became non-leachable after treatment with Terra B. Revegetation was achieved on the tailings beach, with almost uniform colonisation of bulrush and common reed, along with bottlebrush and golden wattle; a variety of reptiles have also been observed on the revegetated tailings beach, along with migrating ducks, spoonbills and grebes.CITATION:Fergusson, L, Blair, D and Scutts, T, ?2014. Treatment and rehabilitation of acidic waste rock and tailings – a 14-year case study, in Proceedings Life-of-Mine 2014 , pp 247–260 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014