Search Documents

By I Canbulat, A Mcquillan

This paper presents a parametric analysis showing the impact of virgin in situ stresses on a shallow (less than 100 to 150 m) high slope in a jointed sedimentary rock environment. Slope stability is assessed at varying ratios of slope orientation and horizontal stresses. The results of this study indicate stress conditions should be included in stability assessments of excavated slopes, particularly where structure is orientated perpendicular to the direction of horizontal stress. Some consideration of stress state is applied in deep open cut pits (eg those with planned excavations of 400–1200 m) (Myrvang et al, 1993; Stacey et al, 2003; de Bruyn et al, 2014; Kozyrev et al, 2015). Dodd and Anderson (1972), Kalkani and Piteau (1976), Lee (1978), Coulthard et al (1992), Noorani et al (2011) have studied the effect or horizontal stress and its impact on slope stability, showing that tensile stresses tend to develop at the crest of the slope, with larger tensile zones for higher horizonal stresses and steeper slope angles (Stacey, 1970, 1973; Sjoberg, 2013). However, the consideration of virgin stresses on shallow slope stability is less frequent (Lynch et al, 2005; Dight, 2006; Lucas, 2006; Sjoberg, 2013). This has led many geotechnical engineers to believe the impact of virgin in situ stresses on open cut slope stability is minimal and not worth time or consideration in modelling, or their effects on slope stability are still poorly understood (Stacey et al, 2003; Sjoberg, 2013).

Nov 29, 2022

By G Harbort, D Zoetbrood

"The Phu Kham copper-gold operation in the Laos People’s Democratic Republic (PDR) is owned and operated by Phu Bia Mining Limited. PanAust Limited holds a 90 per cent interest in Phu Bia Mining Limited, with the remaining ten per cent held by the Laos PDR Government.The original 12 Mt/a copper-gold concentrator at Phu Kham commenced production in April 2008. An incremental improvement program resulted in a number of circuit changes being incorporated by 2011, including conversion of conditioning tanks to flotation cells and the installation of a Jameson Cell cleaner scalper. In 2012 the Phu Kham Upgrade Project was commissioned to increase throughput to 18 Mt/a. In April, 2013 the Phu Kham Increased Recovery Project was commissioned to maximise performance by debottlenecking the plant IsaMill™ regrind and cleaning capacity.With the variable mineralogy of Phu Kham ore, control of the c concentrate regrind circuit is essential in terms of achieving effective liberation to maintain concentrator performance. On a routine basis laboratory regrind signature plot data is compared with daily surveys of the operational IsaMills™. More extensive surveys are also conducted to determine size distribution on a mineralogical basis and the effect of fine regrinding on pulp electrochemistry and flotation performance. This paper provides a review of the operating performance of the Phu Kham IsaMills™ with regard to power draw, feed and product size distribution, feed per cent solids, mineralogy and pulp electrochemistry. Operating performance is compared with the IsaMill™ signature plot test for predicting performance.Citation:Harbort, G, Zoetbrood, D and McNab, B, 2016. Operating Performance of the Phu Kham IsaMill™, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 39–50 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

The Porgera gold mine has made significant progress with the successful installation of a JK FrothCam image analysis system. The system is used to measure and control froth velocity on the scavenger circuit which has brought significant economical and operational benefits. The froth velocity signal, determined by analysis of the camera, is transmitted to the PLC that manipulates flotation cell airflow rate and cell level controllers to maintain a target froth velocity of 130 mm per second. Following on from a three-week trial installation in June 2000, a permanent installation was commissioned on the scavenger Outokumpu (OK150) tank cells. Further work is in progress on the rougher Wemco cells. This paper describes the evaluation of FrothCam Technology and its subsequent installation.

Jan 1, 2003

By J A. Braithwaite

Social licence to operate is not a new concept for the mining industry, referring to stakeholder approval or acceptance for the activities and impacts of a project, company or industry. It is intangible, dynamic and non-permanent, hence it needs to be earned and then maintained (Thomson and Boutilier, 2014). It has also been argued that social licence extends beyond building approval or acceptance, into engagement for long-term development (Owen and Kemp, 2012).There are many examples where stakeholder opposition – or withdrawal of social licence – have increased capital and operating costs, extended schedules and impacted reputation. At its extreme, the withdrawal of social licence to operate can also contribute to or be the catalyst for mine closure.The key benefit of obtaining a social licence is a reduction of risk. Stakeholder support and advocacy, as well as the implementation of social performance programs that contribute to social licence, can be beneficial in terms of schedule, costs and other benefits.While decisions to close a mine are generally driven by resource availability or economic conditions, the social, economic and environmental legacy remaining post-closure is of importance to many stakeholders. With a number of significant mines now approaching closure within Australia, we are seeing heightened community concern about the economic and social impact of mine closure and the success of land rehabilitation. So how does the concept of social licence to operate extend into the closure phase of the mining life cycle?CITATION:Braithwaite, J A, 2016. Social licence to close?, in Proceedings Life-of-Mine 2016 Conference, pp 176–179 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By Savage E. N

Two genetic types of base metal deposits occur in the Wainivesi area of central eastern Viti Levu. The Wainivesi deposit is now considered to be a stratiform volcanogenic type, and the Wailotu and Wainiviti deposits are described as contact metasomatic with some hydrothermal manifestations. The Wainivesi mineralization is correlated with the Tertiary "e" stage, i.e. uppermost Oligocene-Iowermost Miocene. Tertiary "e" stage rocks in Fiji are therefore potential ore producers of stratiform volcanogenic type. On the basis of plate tectonics with Fiji part of the New Hebrides Arc prior to rifting apart in the late Miocene, stratiform volcanogenic deposits of the Wainivesi type may also occur in rocks of comparable type and age in the New Hebrides.

Jan 1, 1976

By S Gillies, H W. Wu

A study has been undertaken into mine ventilation systems currently in use within Australian modern coal longwall (LW) extraction mines. It reviews systems and discusses evolving changes being adopted to address the more complex challenges. There is a strong move to longer panels, wider faces, greater extraction heights, increased production rates, more efficient ventilation and decreased personnel. Each of these changes is motivated by improvement in productivity and generally leads to cost reduction. In addition, mine workings are moving deeper, which results in increased ventilation control issues such as higher total and respirable dust levels, greater seam gas contents in parallel with lower in situ permeabilities, spontaneous combustion and heat management issues. A comprehensive database of Australian LW ventilation practice is analysed. Currently there are a variety of LW panel ventilation circuits used in Australian underground coal mines due to various combinations of seam characteristics, gas emission rates, spontaneous combustion, geological features and surface constraints. The main issues usually addressed in the designing and planning of ventilation circuits for LW panels are airway velocity, gas concentrations, LW cutting methods (eg Bi-di, Uni-di or half web), ventilation of control devices, pressure differentials and leakage paths and understanding gas concentrations across the length and width of the goaf. If the ventilation circuit can manage the applied contaminant load (gases, heat and dust) at an acceptable cost and circuit duty, then supplementary controls, such as gas drainage, refrigeration and dust sprays and scrubbers, may not be required. CITATION:Gillies, S and Wu, H W, 2013. Review of Australian longwall panel ventilation practices, in Proceedings The Australian Mine Ventilation Conference , pp 87-94 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By A D. Campbell, G R. Power

The increasing availability of marker data in sublevel caving operations is changing the way draw can be managed to achieve positive recovery outcomes in these mines. This paper describes how marker data has been incorporated into flow simulations to help calibrate full mine ore recovery simulations for the forecasting and optimisation of recovery.Some flow modelling techniques do not use marker data, relying instead on the outcomes of physical and numerical experiments to guide assumptions about an idealised recovery flow shape. Other mines have access to marker trial data, but find it difficult to specifically link this marker trial information to their recovery models. This can make it difficult to create a link between the marker trial information and recovery forecasting and limits the potential value of the marker trials at the mine.In the simulations shown here, the marker rings are fully incorporated into the flow model, and can be tracked in the model. The model is compared against the real underground marker recovery information to give the user an indication of how accurately the flow settings in the model are reflecting the conditions in the experimental marker rings. An example of use of this system at an operational mine is included.CITATION:Power, G R and Campbell, A D, 2016. Modelling of real-time marker data to improve operational recovery in sublevel caving mines, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 105–110 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By L Y. Yang, Z Wang

This work presents the fundamental properties of CITIC magnetite concentrate and its performance in pelletising and sintering. CITIC concentrate has been widely used in pelletising to produce pellets for blast furnaces. It is also used in sintering to benefit from its sintering performance. CITIC concentrate has excellent balling properties owing to its size distribution, particle surface properties, large specific surface area and balling index, leading to strong green pellets and product pellets. When used in sintering at appropriate levels, sinter bed permeability improves, productivity is increased while coke consumption reduces, and sinter strength improves.

Nov 8, 2021

By K Clode, J Al-Shdifat, S Daykin

Planning for a circular economy allows for previously untapped market opportunities to be explored, resulting in new, innovative revenue generating opportunities, while also reducing environmental impacts. In particular, rare earth elements (REE) are in rising demand as they are key components of over 200 products across a wide range of applications (Xie et al, 2023) including renewable energy technologies. There is a geographical disparity in deposits, with China being the top producer, generating 70 per cent of global production in 2022 (Laboure, 2023). This single dominating source has created supply chain concentration and hence supply risks for other nations, providing a driver for finding alternative sources, such as mine-influenced water (MIW) and tailings. In this study, Isle presents a robust due diligence methodology for undertaking a global horizon scan into REE recovery technology, for a large mining company, from tailings decant water on a specific site. Previous studies of the tailings decant water at this site had shown potentially significant concentrations of both heavy and light REE, but challenges such as high flow, very low pH and high concentrations of iron had previously made recovery unfeasible. Due to these challenges, the horizon scan focused on technologies that had the potential for selective recovery, despite the challenges with water quality, and considered a range of Technology Readiness Levels (TRLs). This included an adsorption-based process that has the potential to selectively separate individual REE, and a polymer based selective flocculation technology.

Sep 1, 2024

By A Mcquillan, N Bar

Geotechnical models developed during the open pit mine planning stage are generally three-dimensional (3D) in component to capture the spatial variation in geological, structural, hydrogeological and geomechanical conditions. Yet when geotechnical analysis is completed, often the 3D geological, hydrogeological and structural models are simplified to two-dimensions (2D). This paper demonstrates this simplification, through referenced case studies, can lead to the wrong failure mechanism being analysed and/or a conservative Factor of Safety (FOS), or Strength Reduction Factor (SRF), being calculated, leading to a false sense of stability. There exists a paradigm that the FOS calculated using 2D limit equilibrium (LE), or the Strength Reduction Factor (SRF) calculated using 2D finite element (FE), modelling methods is generally conservative, ie lower, than the true FOS. However, this assumption that 3D FOS, or 3D SRF, is always higher than 2D FOS, or 2D SRF, is not always correct (Chen and Chameau, 1983; Bromhead and Martin, 2004; Herza et al, 2017; Pyke, 2017; Dana et al, 2018).

Nov 29, 2022

By A Ross, B De Rivaz

The results of full-scale tests on precast segment made at University of Roma are presented. The segments were cast using fibre-reinforced concrete produced without any traditional reinforcement, by using fiber made in high-strength steel and a new type of anchorage.Bending tests were performed in order to check the bearing capacity of the segments under the flexural actions; these occur during de-moulding, handling, storage phases as well as in the in situ condition (due to asymmetric soil pressure). Furthermore, point load tests simulating the TBM thrust were performed, in order to study the construction phase (excavation).The results show that the segment response largely respects the material testing and design advice according to the Fib Model Code 2010. Providing engineers, precast operators and builders confidence in material strengths and design methodology.CITATION:De Rivaz, B and Ross, A, 2014. Full-scale tests on precast tunnel segments made in concrete reinforced with high-strength steel fibres, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 469–476 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By V Rasouli, G Cavanough, A Mokaramian

The sampling time, the costs and its quality are the three factors that determine the best method of drilling in mineral exploration. The two principal methods of reverse circulation (RC) and diamond core drilling are often used in combination by mine operators. RC is used for drilling shallow holes and in-pit grade control, and core drilling for deeper holes to identify future resources. The RC method is faster and more flexible than coring and provides virtually uncontaminated cuttings (ranges from dust to 25 mm chips) to the surface cyclone suitable for geochemical anomalies. The diamond coring produces core samples to increase the level of geological knowledge and the 3D extension and distribution of the orebody. However, both of these methods are subjected to certain limitations and inefficiencies in reaching deeper depths and drilling complex hole geometries. Examples of such shortcomings include the inability to provide enough air pressure for RC drilling and high friction between drill pipe and the hole wall in diamond core drilling.Considering that delivering large volume of reliable samples from deep zones to the surface in shortest possible time is of paramount importance in mineral exploration, and assuming that obtaining core samples over whole overburden is not always essential, then drilling small size holes as fast as possible and delivering the small chip samples to the surface would be a good alternative with several advantages over conventional drilling methods for deep hard rocks mineral exploration. As a result, the use of coiled tube (CT) drilling technology has been proposed recently for such applications. CT is a continuous length of ductile steel or composite tube stored and transported on a large reel; and allows fast drilling by eliminating the connection time and providing continuous circulation during drilling. This enables quick access to the zone of interest to collect the cuttings or obtain core samples. CT is advantageous particularly in drilling directional boreholes and multi-laterals. In this paper, feasibility of using CT delivering reliable samples is discussed for deep mineral exploration. In addition, recent developments and practices are presented that make CT a reliable drilling technology to drill cheaper, faster and deeper and to deliver more continuous and reliable data and samples from deep formations.CITATION:Mokaramian, A, Rasouli, V and Cavanough, G, 2012. Quality sampling using coiled tubing drilling in deep mineral exploration, in Proceedings Sampling 2012 , pp 73-80 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 21, 2012

By A Penney, M J. Pascoe, R M. Stephenson

The empirical McCracken and Stacey stability and risk assessment method has been in use for more than 20 years to assess geotechnical stability issues for raise bored shafts. The methodology has been applied with various levels of success. Increasingly, trends in mining and civil tunnelling have been towards larger diameter, single pass, raise bored shafts to rapidly provide means of ventilation, material movement (ore passes), or emergency egress. Identifying and assessing potentially problematic zones before raise boring commences can allow for appropriate risk-based decisions on construction, or to investigate alternative solutions. The implementation of a proactive solution to raising through an identified weak zone is preferred to the application of an engineered solution to an area subjected to substantial instability or failure. Methods for investigating potentially problematic areas are discussed in this paper based on AMC’s benchmarking data. Proactive investigation programmes resulting from these investigations are also discussed. Previous publications discussing the benchmarking data have concentrated on Australian case studies. Increased efforts and recent updates have been made to expand the database to include international case studies. This has provided further refinement of lower bound ‘raise bore rock quality index’ (QR) values, and various rock mass parameters for stability assessments. CITATION:Penney, A, Stephenson, R M and Pascoe, M J, 2018. Raise bore stability and risk assessment empirical database update, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 434–445 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By C Jacobsen, N Harries

Assessing and managing instability hazards is an essential activity when working with unstable natural slopes and excavated open pit mining slopes. Slope monitoring has become the standard technique for the management of geotechnical risks associated with mine slope instability hazards. In recent decades, a proliferation of new monitoring techniques such as terrestrial radar, satellite InSAR and LIDAR have become standard operational tools, complementing conventional survey-based monitoring solutions. A reliable monitoring system should identify and record incipient anomalous slope movement. Although the most obvious purpose of a monitoring system is safety related, slope deformation and performance monitoring also enhance the understanding of slope behaviour and assists in improving system design and implementation. For a monitoring system to be considered an effective early warning tool, it needs to operate in real-time and should be linked to the mine’s emergency communication systems. Terrestrial radar systems have been developed that can provide near real-time measurements, at a high level of precision and covering broad areas in all weather conditions. This has had a positive impact on the management of geotechnical risks in operational conditions. The technology adoption of RADAR in mine monitoring has significantly progressed in the last 20 years from technology enthusiasts, to visionaries, to pragmatists to conservative users. However, the increasing adoption of RADAR cannot reduce or remove other monitoring techniques that often have important benefits; even if these technologies cannot be used as a real-time operational tool. An increasing awareness on the importance of combining data from different monitoring techniques to develop a holistic picture of all possible geotechnical hazards is a current industry trend. This is proving to be an excellent foundation for managing hazards associated with slope instability in open pit mines, and is only expected to improve with time with the adoption of new technologies based on big data and Artificial Intelligence (AI).

Nov 29, 2022

Geochemical data on Australian granites and pegmatites9 and the.,mineral.components of these rocks, is presented and compared with that obtained in similar studies in.the U.S.òS.R and:.elsewhere.The petrochemical character of tin granites and the trace.-chemistry of their component minerals, particularly biotites, have some significance as ore guides in prospectingfor tin.The primary geochemical dispersion of tin can be readily tested both in the laboratory and field by colourimetric methods, after volatilization with ammonium iodide, using modifications of.the method described by Wood (1958).Secondary dispersions of tin in residual soils or.alluvia can likewise be readily tested by rapid colourimetric methods in the field, but simple hydraulic methods,.handling larger-. sample volumes, give reliable outlines of dispersion patterns.

Jan 1, 1963

By S Ellis

In January 2008 Chirano Gold Mines Limited committed to expansion of the Chirano Gold Project from its existing design capacity of 2 Mtpa ROM ore to a new design value of 3.5 Mtpa. In addition to increased throughput, the design had to contend with increasing ore hardness and competency, while at the same time make cost effective use of existing equipment with minimum disruption to existing production. The solution adopted involved some novel approaches including tertiary crushing and operation of the SABC circuit in overflow ball mill mode and parallel elution with a common acid wash column. This paper describes the approach taken to the design of these elements to achieve a cost effective and safe capacity expansion.

Aug 8, 2011

By A M. Lechner, V Glenn, M Edraki, D R. Mulligan, C Unger

With more than 50 000 recorded abandoned mines in Australia, effective management strategies are needed to prioritise and manage health, safety, environmental and socio-economic risks and opportunities. This paper reviews international leading practices for abandoned mine management and identifies key issues that need to be addressed in the Australian context. As well as the academic literature, this review draws on a 2008 global legacy site survey and forum in 2008, a Churchill Fellowship study of abandoned mines and the recently released æStrategic Framework for Management of Abandoned Mines in the Minerals IndustryÆ (MCMPR/MCA, 2010).A conceptual model was developed to identify the relationship between key issues affecting the management of abandoned mines in Australia. The conceptual model is then used in the development of a maturity chart which draws on risk management principles to provide leading practice guidance for abandoned mine managers, jurisdictions and stakeholders. The maturity chart approach for risk management has been successfully used elsewhere to evaluate safety, environmental and socio-economic maturity.CITATION:Unger, C, Lechner, A M, Glenn, V, Edraki, M and Mulligan, D R, 2012. Mapping and prioritising rehabilitation of abandoned mines in Australia, in Proceedings Life-of-Mine 2012 , pp 259-266 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By J Stipcevich, N Patel, J Faithful5, S Narendranathan, L Tatnell4

ENGIE, the current owner and operator of the Hazelwood Open Cut coalmine, are in the process of rehabilitating the mine site in preparation for mine closure. Bucket wheel excavators (dredgers) used during coal mining operations are in the process of being demolished, which involves the controlled felling of dredger components using explosives. With the mine located in close proximity to the Morwell township and other critical public infrastructure, it is crucial that the use of explosives and the possible implications for mine stability is well understood. The felling of Large Mining Equipment (LME) will apply an impact load immediately to the underlying coal benches with the adjacent coal batters potentially at risk also of adverse slope stability impacts. This paper presents the 3D stability modelling methods employed to successfully assess the potentially adverse stability implications associated with LME collapse.

Jun 21, 2022

By A Llewellyn, M Varvari

The ventilation circuit at the FrogÆs Leg Mine was originally designed to permit mining to progress down to 440 m below surface at a maximum production rate of 500 kt/a, as per the feasibility study. The FrogÆs Leg resource has now been defined down to 640 m below surface at a maximum production rate of 750 kt/a. In order to allow for this increase in production depth and tonnage, it was necessary to upgrade the ventilation circuit.This paper outlines the upgrades to the ventilation circuit that were undertaken and the underlying rationale behind them.CITATION:Llewellyn, A and Varvari, M, 2013. Ventilation upgrade at the FrogÆs Leg Mine - Case study, in Proceedings The Australian Mine Ventilation Conference , pp 95-102 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By A B. Richards

A brick veneer house located on a open-pit coal mine lease has been subject to ground vibration levels of up to 222 mm/s, and air vibration levels of up to 145 dBL. The dynamic response of the structure was measured with accelerometers, geophones, and strain gauges as part of a project investigating the response of brick veneer houses to blasting. This paper outlines the project, and provides information on brickwork strength, foundation investigations, and observations on damage due to blasting. Correlations have been made between crack behaviour and factors such as blast vibration levels and rainfall.

Jan 1, 2001