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By P Ritchie, E H. Briese, N A. Currey

Kidston Gold Mines, located in semi-arid North Queensland, Australia is currently in its closure phase. Highly innovative and comprehensive rehabilitation strategies were employed at the site, including the direct revegetation of the surface of the tailings storage; the construction of a tailings sediment entrapment pond; the construction of a spillway to drain large rainfall events from the surface of the tailings; the construction of store/release covers over the tops of the waste rock dumps; the sheeting with oxide waste rock of the waste rock dump slopes; the partial back-filling of the initial Wises Hill Pit with waste rock and thickened tailings produced from the subsequent Eldridge Pit; the partial flooding of Eldridge Pit following the end of mining; and the construction of wetland systems to treat contaminated tailings and waste rock dump seepage. These closure strategies involved the careful consideration of water management. Specific water management issues included understanding the water balance of the tailings dam; the operation of the tailings dam sediment entrapment pond and spillway; understanding the water balance of the store/release waste rock dump covers; the importance and sustainability of vegetation on the tailings, store/release waste rock dump covers, and on the sheeted waste rock dump slopes; the level and quality of water in the partially flooded Eldridge Pit; and the treatment of contaminated seepage in the constructed wetlands. The seasonal and highly variable rainfall experienced in this semi-arid climate posed a number of challenges for the management of water on the site post-closure. The paper details these challenges and highlights how they were resolved over the period leading up to and following the end of mining.

Jan 1, 2003

By J S. Kuszmaul, T O. Aspinall

The applicability of environmental geotechnics for erosion management is increasing in importance worldwide. The environmental impact of mining and evolving environmental legislation has been receiving increased attention worldwide in the last two decades (Bradfield, Shultz and Stone, 1996). The potential impacts associated with unstable spoil dumps from mine operations is the focus of concern both by the mining industry, environmental legislative agencies and members of the public. This is because of the need to increase the reliability of erosion prediction and in the minimisation of costs for spoil dump design. Engineered slopes of mine spoils may be stable at the end of construction, but they can deteriorate over time. Engineering design of mine spoil dumps seeks to reduce the potential for such erosion damage through correct selection of an initial stable landform scheme (Goh, 1997). The design of mine spoil dumps must also conform to the specifications of evolving legislation. The Queensland Environmental Management Overview Strategy (EMOS) states that, for minimised degradation of the surface area due to erosion during the development of a project, the erosion rates should be between 12 - 40 tonnes/hectare/year and that the depths of rills and gullies be limited to less than 30 cm (QDPI, 1988). The aim of engineering design is to ensure the long-term stability of the spoil dumps. The implementation of effective planning and operating procedures through recontouring and grading assists in the reshaping of spoil dumps to a safe, stable and non-erodible environment.

Jan 1, 1998

Confirmation that acid drainage (AD) was a significant environmental issue for the Australian minerals industry came in 1992 with the first national workshop on the topic. Subsequently the extent of AD was documented in a national survey published in 1997. The recommendations arising out of that survey served as a platform for actions by government, industry and industry-support organisations such as the Australian Centre for Mining Environmental Research (ACMER) to enable more effective prevention and management of AD. This paper briefly documents the extent of AD in the industry, the government regulations and guidelines for AD management, industry initiatives, the role of ACMER and other organisations in assisting industry through research and technology transfer, and the efforts being made to deal with AD at derelict mines. Future management of AD in the industry will be assisted by the linkage of Australia (through ACMER) into the International Network for Acid Prevention (INAP) which is facilitating the interchange of knowledge on AD as well as coordinating global research on the topic.

Jan 1, 2003

The Mt Lyell Mine at Queenstown, Tasmania was re-opened in 1995 by Copper Mines of Tasmania Pty Ltd, a wholly owned subsidiary of Mt Lyell Mining Co Ltd. The re-opening followed over 100 years of copper and gold mining at Mt Lyell. Major changes in practice were implemented across the site. Preventing further damage to an already disturbed environment was a major priority. Sublevel caving, at a lower cut-off grade, replaced open stoping for the deep underground mining. Development and later stoping are handled by a contractor, National Mine Management Pty Ltd, in the largest underground contract awarded at the time. Large scale sublevel caving was new to Mt Lyell and not widely practised in Australia, requiring studies and systematic development of the method, particularly in drilling and blasting. Rehabilitation and upgrading of mine infrastructure have been and will continue to be a challenge. The mine has, since 1995, returned to being a stable producer with potential for growth.

Jan 1, 1998

By B Hayes

The Ambuklao and Binga Rehabilitation Project is a 175 MW hydro power project currently under construction across dual sites in the north region of Luzon Island, Philippines. When it was built in 1956, the Ambuklao Dam harnessed the second largest hydro-electric reservoir in Asia. However, due to landslide erosion and prolonged silt infiltration caused by an earthquake in 1990, the power plant has been rendered inoperable since 1999.To bring the power generating facility back to life, the project scope entails the rehabilitation and construction of civil structures, shafts and tunnels. A major component of these works is the decommissioning of a section of the seven metre diameter headrace tunnel by installing a concrete plug. The headrace tunnel is part of a closed waterway system that connects the dam via a shaft, exhibiting a hydrostatic pressure of 13 bar (1300 kPa) at the location of the new tunnel plug. In addition, the power station ball valves have seized ajar and the damaged intake riser is unsafe toaccess thereby requiring the plugging operation to be carried out under live flowing conditions.Working under hydrostatic pressure and live conditions, the headrace plug will be an underwater tremie pour operation that includes drilling and concrete injection through blow out preventer caissons installed in the floor of an underground chamber above the tunnel. The purpose of this paper is to describe the key engineering and planning components involved in this operation including pre- and post-grouting, chamber crane, sonar, local water compensation, jet flushing, drilling, caisson installation, and concrete design, production, delivery and placement. The success of this task rests on the strategic preparation and operational management of risk and safety in a challenging rural environment.

Mar 8, 2011

By T Alexieva

Since the early 1900s the geotechnical community has investigated every significant failure of a tailings dam, improved our knowledge of the behaviour of the tailings storage facilities, developed analysis methods, compiled lessons learned, and committed to zero failures. The rate of occurrence of tailings dam failures has reduced since the 1980s, however, failures continue to occur and continue to surprise us. At BHP, we have decided to take an approach to the tailings management that is similar to the approach to safety. We are looking at ways to eliminate, substitute, separate or engineer around the hazard (tailings dam failure). As such, our ultimate long term goal would be to eliminate the need for new tailings facilities. Unfortunately, we have not developed yet technologies for extracting many of the common metals and minerals without producing tailings. Our shorter term goal is to substitute the current conventional slurry tailings facilities with less risky dryer facilities. We are working with vendors and research organizations to develop technologies that can be efficiently applied on a large scale. At the same time, we are committed to using the best available engineering to reduce the risks associated with our existing and new conventional tailings facilities. The best engineering can be achieved by people with the appropriate education, experience, attention to detail, discipline and authority. We have implemented a system of governance to make sure, we have the best engineering applied to all our facilities, considering the specific conditions at each site.This paper presents the current tailings governance process at BHP, and the initiatives that were undertook towards achieving a zero failure goal. CITATION:Alexieva, T, 2018. Tailings governance, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 2–7 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By G Marling, A Calderon, J Harris, P Kirsch, M Shi, D Sprott, A Kirsch

Large-scale infrastructure construction needs to comprehensively manage risks that can impact the health and well-being of many people, from workers (temporary, contracted or full time), to families and surrounding communities. This paper starts with an analysis of incidents (injury, fatality, other damage) in tunnel construction between 2000 and 2014 and assesses the distribution of these events by continent, year, and severity of outcomes. These incidents are then analysed and mapped to a framework of hazards derived from RISKGATE (2014). A comparative register of current tunnel construction risk management guidance is derived from current Australian codes of practice and this register is also mapped to the RISKGATE framework of hazards to identify where coal industry knowledge may offer utility to the tunnelling industry.An initiative of the Australian Coal Association Research Program (ACARP), RISKGATE is an interactive online risk management system developed to assist the mining industry in implementing continual improvement in the management of major unwanted events. To date, a comprehensive knowledge base has been captured for risk management of tyres, collisions, fires, isolation, strata underground, ground control open cut, explosions, explosives, outbursts, coal bumps and bursts, human/machine interface, manual tasks, slips/trips/falls, inrush and occupational hygiene. By capturing operational knowledge from industry experts, RISKGATE provides a cumulative corporate memory at a time of high personnel turnover in the coal industry.This paper proposes and outlines how knowledge within the RISKGATE platform could be applied to managing the significant health and safety risks associated with tunnelling. The authors suggest that to varying degrees the knowledge already captured in RISKGATE is likely to be transferable to tunnelling construction operations. Please note that this paper focuses on tunnel construction and does not address risk management of tunnels in operation (eg road transportation or utility networks).CITATION:Kirsch, P, Kirsch, A, Calderon, A, Marling, G, Harris, J, Shi, M and Sprott, D, 2014. Management of health and safety in tunnelling – application of Australian coal mining knowledge, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 563–572 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By V Pfannenstiel

The United States (US) coal mining industry has been working under comprehensive planning, operating and rehabilitation regulatory requirements for nearly 35 years. The public desire for environmental protection during mining and rehabilitation following mining to achieve post-mining land use and sustainability goals has been a major factor and continues to influence the process. Mining companies have evolved operations to achieve outcomes that address the desired goals and regulatory requirements cost-effectively and successfully. Over the 35 year regulatory period, requirements for more diverse topography, specialised revegetation communities, landform stability and assured sustainability have increased and become more complex. These challenges are effectively met by maximising integration of mine planning and operating with the rehabilitation process. Rehabilitation is then implemented in a more timely and efficient manner and with effective results that achieve desired outcomes, commonly with added value. Peabody Energy (Peabody) has taken this approach in its US operations and this paper discusses an integrated approach and illustrates learnings and results with examples from several of its western US operations.CITATION:Pfannenstiel, V, 2012. Integrated planning, mining and rehabilitation for effective results and sustainable land use - A western United States perspective, in Proceedings Life-of-Mine 2012 , pp 219-232 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By B N. Noller, J C. Ng, S L. Bruce

Mining activities can result in the transfer of harmful elements, including arsenic and lead, into the environment. In Australia, one of the potential future uses of rehabilitated mine land is to stock grazing animals. Elemental uptake is dependent on bioavailable fraction for adsorption upon exposure. Bioavailability data are generally lacking in order to provide realistic health risk assessments relating to harmful elements from mine tailings in Australian conditions. Another key component of risk assessment is the ability to estimate a realistic exposure, or dose rate, of the tailings to the grazing cattle over a set period of time. Hence, we aimed to conduct grazing trials directly on rehabilitated tailings facilities in order to provide valuable in situ information on heavy metal dose rates and associated accumulation. For the laboratory-based evaluation of comparative bioavailability, groups of cattle were fed five days a week on a normal diet spiked with mine tailings or soluble pure salts of target elements (eg sodium arsenate, sodium arsenite and lead acetate) for about eight months. For the field validation, cattle were allowed to graze directly on rehabilitated tailings facilities over a similar length of time. Blood and a biopsy of the muscle and liver were periodically collected to monitor arsenic accumulation. At necropsy, blood, muscle, liver, kidney and other saleable tissues were measured for arsenic concentrations. Although this study was focused on arsenic, lead and other metals were also measured. Predictive models for arsenic and other metals have been established to calculate the maximum grazing duration without the risk of exceeding specific food safety guidelines. The outcome of this study is a predictive model for maximum beneficial use of certain rehabilitated tailings for cattle grazing where grazing activities do not impact on the integrity of the tailings dams.CITATION:Ng, J C, Noller, B N and Bruce, S L, 2014. A predictive model for beneficial use of rehabilitated mine tailings for grazing cattle after mine closure, in Proceedings Life-of-Mine 2014 , pp 563–572 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By C G. Sweeney

The underground mining industry is seeing unprecedented shortages in skilled labour. Migration to Australia being at an all-time low is a leading concern, with pandemic-induced border closures and lockdowns only exacerbating the skills shortage, not causing it. The skills shortage is forecast to peak in 2023 and remain high beyond 2025. With this skills shortage in mind, mining companies throughout Australia are trying to deal with stricter protocols around Health and Safety (H&S) legislation, as well as more stringent controls on quality assurance, particularly as underground mines are reaching greater depths and extending into ‘unchartered territory’. The cumulation of this is proving to be a major hurdle in ‘effective’ operational geotechnical management. The drive for automation in mining is bringing another level of complexity. However, ‘once automation is up and running, it presents the opportunity to access talent pools that may not normally be available. There is also a change in skillset that will be required to drive automation. ‘The top two emerging roles that will be critical for the future of the mining industry are artificial intelligence and machine learning (AI/ML) specialists, and process-automation specialists’ (Writer, 2021). If anything positive has come from the pandemic, it has shown that remote working can be effective and that the drive for automation and critical evaluation of skills required on-site should be given greater priority. UQ acknowledges that the industry is changing, and that digital technology is required to be offered in mining related disciplines. Industry and academia need to do more to promote geotechnical engineering in mining and balance the curriculum to suit the future of mining and make it more enticing. The average cost of a geotechnical failure is about $5 million in coalmines and can be into the hundreds of millions of dollars if production is affected (Cartledge Mining and Geotechnics, 2020). The cost of a good geotechnical design far outweighs the potential losses if a failure were to occur. This alludes to the growing importance of experienced geotechnical consultancies playing a pivotal role in managing mine site geotechnical hazards, while the industry is developing the next generation of geotechnical engineers.

Nov 29, 2022

By C A. Chaves

During most of its history, the metallurgical industry has been seen as a source of pollution for the environment. However, during the second half of the 20th century, as the world environmental legislation became more protective and the global environmental conscience consolidated, this landscape began to change. Metallurgical activities have become increasingly related to the social and environmental impacts caused by human activities. With the adoption of environmental management in steel plants, there has been a significant change in steel-related activities which have begun to introduce modern plants, managed with environmental, social and productive efficiency. More and more, steel companies search for a decrease in negative impacts of their industrial operations on the environment, fitting them to the current environmental legislation and even increasing productivity and profitability. The steel industry has started to become a clean and more efficient industry. This work presents a case study of a sustainable steel plant project, located in an environmental preservation area. The project includes treatment and reuse of industrial liquid effluents, air emissions control, noise control, recycling, recovery and adequate waste management. It also incorporates production processes using clean technologies, capable of coproducing energy resources which may be used in the plant showing how is it possible to produce steel with environmental and social responsibility and even increase the enterpriseÆs profitability.

Jan 1, 2009

By S Porter

The Melbourne City Link Project is a privately funded road infrastructure project linking three significant existing freeways in the vicinity of the Central Business District. The State Government, through the Melbourne City Link Authority, has contracted Transurban to build, own and operate City Link for a concession period of 34 years before the road network is transferred to the State. Transurban has a contract with Transfield Obayashi Joint Venture (TOJV) to design and construct the works. The project is divided into the southern and western sections and the tunnel works comprised the significant component of the Southern Link. Outside of the cut and cover tunnels at the portals, the driven tunnels component was constructed by TOJV direct labour. TOJV subcontracted all design work to a joint venture of Hyder Consulting and CMPS&F (Hyder/CMP). The geology in the tunnel corridor and generally below the city of Melbourne is highly variable and constantly changing. The tunnels were driven, for the most part, in siltstone and sandstone of the Silurian age, but also intersected overlying basalts and clays. The Silurian bedrock is a fractured aquifer that is connected to overlying alluvial aquifers. Consequently, the construction of the tunnels was a complex engineering task. This paper details the operational relationships and procedures developed to deliver a design that was aligned to the construction constraints and delivered an end product that met all technical, quality, cost and program goals.

Jan 1, 1999

By S Mundell, A Atkins, S van de Water

Geoscientific information management enables the capture, management and delivery of the original geoscientific observations and measurements of the earth’s natural resources. However, original observations and measurements are worth nothing if the quality and integrity of the data can’t be guaranteed. Geoscientific information is one of the fundamental assets enabling miners to make confident and accurate business decisions, whether that is defining a resource model, performing reconciliation, delivering ore reserve reports or meeting environmental compliance requirements. Without access to reliable, validated or verified data it increases the risk of miners using incorrect information for reporting and compliance. Industry codes, such as JORC, or government regulations, such as environmental compliance requirements, must be adhered to and companies should be able to confidently report to these standards. Without having a robust information management framework in place, it becomes a challenge to make trustworthy decisions, report confidently and reduce the risk of non-compliance. As a key initiative, good data governance should form one part of a miner’s information management strategy. Within the mining industry it is common for companies to only consider technology tools as the key focus for compliance whereas a mature information management focus will additionally consider people and process. All three pillars are critical for a miner to have confidence in their data driven decisions. This paper discusses an industry framework for best-practice geoscientific information management based on the observations gathered from analysing data management practices within the mining industry. It focuses on how the three pillars of people, process and technology are crucial elements to improve operational decisions and ensure companies are compliant.

Nov 8, 2021

By K Biegaj

During the author’s 25+ year career in mine management in various parts of the world (mostly in Australia), the author has been privileged to live and work in mining towns (not FIFO) for more than 20 years. And has personally observed other people from the mining industry carrying out work at home in an unsafe manner, eg pushing lawn mowers whilst wearing thongs or performing electrical jobs whilst standing on aluminium ladders, as well as many others. It is common that injuries sustained at home whilst on break are not reported upon arrival back on a mine site. A large number of compensation claims for injuries at work, which in fact had been sustained at home, come at substantial extra costs to mining companies.

May 5, 2022

By S Harvey

An inrush of water or mud into an underground mine, or sudden subsidence above mining voids represent low probability but high impact risks in underground mining. About two such incidents involving multiple fatalities or loss of production are reported each year worldwide. On average, Australia experiences one such incident every three to four years. This paper reports the development of a Standard that is intended to eliminate fatalities due to inrushes and subsidence.

Jan 1, 1998

By T Hirsi, M Weatherseed, T Ritasalo

Cooling tower design has not advanced significantly in the last decade. Recognising this, Outotec has developed an innovative horizontal outflow cooling tower with increased performance compared to conventional design cooling towers.Outotec® Cooling Towers operate today in applications such as spent electrolyte cooling in zinc plants and for gypsum removal before copper solvent extraction. In such applications the use of this latest design has enabled increased production and lower maintenance costs in the downstream operations.In actual operations, the cooling performance has been confirmed at start-up, and has demonstrated that the towers operate in accordance with the CFD modelling. In the last three years these towers have proven themselves in commercial operation to operate with high efficiency and availability.This case study will outline comparative data, collected over two years at a site where both Outotec and conventional cooling towers are operating. The data shows that Outotec cooling towers require less than half the maintenance time of conventional cooling towers, when adjusted to a total solution flow basis. A close partnership approach with the site has allowed continual development, ensuring high availability and high performance.Experience with previous cooling tower installations guided the development of maintenance philosophies and procedures; this resulted in a design where maintenance intensive components were accessible from the top of the cooling tower. This allows safe access to components and maintenance with little or no downtime.CITATION:Hirsi, T, Ritasalo, T and Weatherseed, M, 2015. Improving cooling tower performance with innovative horizontal outflow design, in Proceedings MetPlant 2015, pp 396–402 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By P Thwaites

The mining industry uses many types of mineral and metallurgical plants to produce saleable product from ore mined. Plant design history has left current operations with a mixture of manual operation and various forms of automated process controls. Consequently, we typically see high-variability in the continuous operations together with a shortfall in the attainment of full capacity or higher utilisation of consumables.At a level of best practice, ‘operational performance excellence’ focuses on process control, using automation and control systems to deliver process optimisation. This more sophisticated delivery is a great deal more difficult than the first stage of equipment selection/installation. It includes the appropriate selection of the right instrumentation and control system, key process knowledge, individuals with a solid control engineering background/experience and the essential backing/support of the operations management team together leading to higher-value delivery. Robust solutions can be realised, considerably minimising process variation, thus leading to process optimisation. This approach results in an easier, efficient and safer process while providing considerable returns for the plant owners.How variable are your processes, and do you maintain optimised process performance with dedicated resources, modern instrumentation, ‘best practice’ control systems and performance monitoring tools? In this paper, these questions and their possible answers are discussed.I say we can do much more and be ‘more efficient’ in our efforts to remain competitive. This area remains a major opportunity for improved efficiency, minimising tailings losses and other milling costs.CITATION:Thwaites, P, 2014. Manual control, process automation or operational performance excellence – what is the difference?, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 13–40 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By J A. M Luz, A T. Bernardes

HukkiÆs law is an empirical law, which does not take into account several events of energy loss during the fragmentation processes. Since experimental results are very difficult to obtain, for a large range of fragment sizes, the verification of the law is very difficult. The relation between fractures and fragmentation processes with fractal geometry was proposed some decades ago. Empirical laws known in this context show basic features of fractal geometry, mainly self-affinity and power law behaviour. Thus, in this work a model was developed to simulate the fragmentation process and to check the relation between energy consumption and fragment sizes. The model is represented on a regular lattice. Links can represent pathways for fracture processes. The events of fragmentation have energy given by a probability distribution function. In the model there is no mass loss. Propagation of fractures occurs as self-avoiding random walks on the regular lattice.

Sep 26, 2011

By B Chapman, B Gaida, L Drowley

The 372 MW Ulu Jelai Hydroelectric Project is a peaking power scheme located in the Cameron Highlands, Malaysia. The main features of the project include an 84 m high roller compacted concrete dam; two weirs which divert flows from adjacent catchments via transfer tunnels into the main reservoir; an underground power waterway; and an underground power station complex comprising three large caverns with connecting tunnels approximately 240 m below surface level. The project includes approximately 25 km of tunnels excavated in fresh granite rock mass with some distinct shear zones of weaker material. The majority of the tunnels are being excavated using drill and blast, with the two transfer tunnels being excavated with a tunnel boring machine (TBM).This paper focuses on the design and construction of the Telanok underground power station complex and also some aspects of the design for the headrace tunnel. Topics covered include geological site investigations including in situ measurements of rock stresses; development of a geological model and parameters for rock support design; three-dimensional modelling to assess interactions between the caverns to optimise rock support; design of a rock anchored crane beam; construction of the caverns and design of the unlined headrace tunnel taking into account hydraulic jacking and operational pressure fluctuations.CITATION:Drowley, L, Gaida, B and Chapman, B, 2014. Design and construction of large caverns in granite – Ulu Jelai Hydroelectric Project, Malaysia, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 361–368 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By A Black, A de Jo, J Cavanagh, J Harding

Acidic and metal-rich waters have been discharging from Sullivan Mine, West Coast, New Zealand since the closure of the mine during the early- 1990s. This has resulted in a decrease in pH from a background of 4.5 to 2.8 and an increase in metallic elements in nearby Rapid Stream. In addition to the chemical effects on Rapid Stream, a study of freshwater macro-invertebrates revealed the absence of most biota downstream from the discharge. An attempt is being made to use the Sullivan Mine as a case study of problem and remediation analysis.

Jan 1, 2003