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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 P Viljoen, A Holland, C Parken

In the raisebore industry, there are two known methods of removing large diameter reamer heads once the reaming of an underground shaft is complete: 1. Lower the reamer head to the base of the shaft and use a thermal lance to cut the drill string and drag the reamer away from the hole. This method exposes the person doing the job to falling rocks from the unsupported mineshaft, a hazard which is difficult to control and has caused fatalities. 2. Install breast plates in the backs above the reamer head at the top of the hole, and use air hoists to lift the reamer out of the hole. Steel beams are then placed across the hole which the reamer is lowered down onto, dragged forward away from the hole, disassembled, and removed. This method is time consuming, expensive, and complex in the controls required to ensure safe completion of the job At Carrapateena, the air hoist method had been successfully used, however, with the cost involved and the complexity of this process, development of an improved and fit for purpose reamer removal method was pursued. OZ Minerals collaborated with Pybar to develop an industry first application of Enerpac SL100 lift and shift technology; a track mounted system with hydraulic lifting units that can both lift the reamer out of the hole and tram it back along the tracks away from the hole. A key component of turning the idea into a reality was by establishing a truly collaborative relationship between client and contractor. When the SL100 mobile gantry arrived, it was set up in Adelaide and trialled with the whole raise bore crew attending the two-day workshop and risk assessment; a rare opportunity for drillers. There have now been five successful reamer removals with the SL100 mobile gantry at Carrapateena. It has proven to be an efficient process with the entire process from setup to demobilisation taking less than 48 hours. This new way has completely removed hot works and uncontrolled hazards from working at the bottom of a shaft. It has also saved the reamer stabiliser from being cut and thus wasted. Exposure to the open hole has been minimised significantly as assembly of the SL100 is completed well forward of the open hole. This new process is exponentially safer, quicker and cheaper.

Mar 15, 2021

By Z R. Guo, Y Qiu, X F. Wang

Mechanical damage leads to the increase of effective stress of sediments, and pore closure hinders the discharge of methane gas. Ignoring the influence of mechanical damage leads to an excessive prediction of hydrate gas production. Therefore, a fully coupled model considering mechanical damage-chemical decomposition-gas-water two-phase seepage-temperature was developed in this study, and the model was verified by Masuda experiment. Based on the fully coupled model, the temporal and spatial evolution of the whole process of hydrate decomposition under the influence of three initial absolute permeabilities, three pressure drops and three water saturations were considered. The results showed that: • The gas production rate reached the peak value in a short time after depressurisation, and the peak value increased with the increase of the absolute initial permeability. The larger the initial absolute permeability was, the faster the damage variable reached the peak value. The porosity increased gradually before the damage variable reached its peak, and the gas flowed more easily. • When the pressure drop was low, the hydrate remained stable in solid form. As the pressure drop increased, the hydrate gradually began to decompose. The greater the pressure drop was, the faster the initial decomposition rate of the hydrate was. So the damage variable increased rapidly and the porosity increased continuously, resulting in a large gas production rate at the initial stage of decomposition. • The larger the initial water saturation was, the smaller the effective stress wss, resulting in the slow growth of the damage variable and the small change of porosity.While the gas relative permeability was small, it resulted in a smaller gas production rate, and hydrate decomposition was slower. • The damage variable showed a process of rapid growth first, then slowly increased to the peak, and then gradually decreased to a stable state. When the damage was considered, the hydrate decomposition time to the steady state was longer, and the gas production was about 80.68 per cent of that without considering the damage.

Nov 29, 2022

By S Talu, E Savage, S Howe

Major falls of ground, strainbursts, airblast and mudrush events are the major hazards in block caving environments, resulting in both safety and financial consequences and losses. Rio Tinto mines have developed strategies to reduce the likelihood of these events occurring. However, until recently, there have been no tools available to monitor and manage these hazards in real time.Mira Geoscience and Rio Tinto have collaborated to develop real-time geohazmaps to monitor and manage major cave hazards. These geohazmaps are used by mine planners to integrate multiple hazard parameters that contribute to form a combined hazard rating.The benefits of implementing geohazmaps include safety and cost improvements through the early identification of potential locations for major events. These cost savings are realised in the design phase, where development and critical infrastructure is located in areas of lower hazard rating. Additional improvements can be achieved by taking the hazard level into consideration when planning the production and development schedules and ground support design.CITATION:Talu, S, Savage, E and Howe, S, 2016. Geohazmap implementation in block cave mines, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 817–822 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By C X. Zhang, W K. Ru, S C. Hu

To study the creep properties and the energy evolution characteristics of the weakly cemented rock (WCR) in western China, the creep deformation damage law of weakly cemented mudstone (WCM) under graded loading and the energy evolution characteristics of each creep stage were analysed based on the triaxial graded loading creep test of WCR. The results showed that as the confining pressure increased, the creep failure strength of the WCM increased from 9.5 to 24.8 MPa, and the relative displacement of the mineral particles in the mudstone increased gradually, resulting in a reduction in the fracture angle from 79.7° to 58.3°. At the same stress level, the strain energy Ue, the total energy U, and the dissipation energy Ud all increased as the confining pressure increased, but the growth rates of U and Ud decreased gradually, while the growth rate of Ue remained high. At the end of the stable creep stage, Ue increased slowly with the confining pressure, while U and Ud increased rapidly with the confining pressure, and their growth rates were basically the same. At the end of the accelerated creep stage, the growth trends of these three energies were all positively correlated with the confining pressure, Ue was significantly lower than that at the end of the stable creep stage, and Ud and U were further increased. These results revealed the unique creep properties and energy evolution characteristics of the WCR, providing a theoretical basis for long-term stability control of roadways that are built with WCR.

Nov 29, 2022

By G Noonan, S Thomas, M Limbert

Stuck drill rods (often referred to as bogged rods) in production ‘upholes’ are a common problem in the underground mining industry. Bogged and broken off drill rods have the potential to fall out of the hole without warning, posing a serious hazard to personnel and equipment below.Current industry practice to alleviate this hazard can be to either grout the hole in order to lock the drill rods in place, or to ‘plate over’ the hole with a rock bolt. Each of these operations seriously delays mine production as both require demobilisation of the production drill and mobilisation of alternative personnel and equipment to address the hazard. Both methods have been assessed for safety and efficiency and were found to be expensive, time consuming and in the case of plating over, ineffective.To address the safety and efficiency short-comings of the traditional practices, the long hole plug (LHP) has been developed to safely secure the lost rods in the hole. The LHP when struck by falling drill rods behaves similar to an expansion shell anchor transferring the axial forces from the falling drill rods horizontally into the rock mass. It is installed using standard production drills allowing work to safely continue with little interruption.Extensive testing has been carried out on the LHP in the laboratory and underground at the Rosebery mine on the west coast of Tasmania, Australia. Testing has included static pull testing, full scale drop testing and underground trials.The outcome of this work has proven the LHPs ability to add safety, volume and cost benefits to the Rosebery underground operation and it is currently in use at that site. It enables proven elimination of a common workplace hazard immediately, thus eliminating delay on the mine’s production cycle.CITATION:Thomas, S, Noonan, G and Limbert, M, 2017. Long hole plug – addressing the hazard of bogged rods in ‘upholes’, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 305–310 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017

By D Nieuwkerk, V J. Absolon

"Screw press technology is an innovative approach to tackling the growing pressure to conserve water and minimise the environmental impact of mineral tailings disposal. The principles of the technology have been known for a considerable period of time in non-mining applications such as water treatment, wastewater (municipal sludge), as well as in the paper and chemical industries for dewatering solids, particularly those containing clays.The screw press represents a viable niche technology for filtering fine and high-clay tailings, without the prior thickening stage, and is capable of producing a filtered product that is sufficiently consolidated and dry enough to provide a product suitable for conveying and dry stacking.The Ishigaki screw press was introduced in 1990 and key features are: continuous operation and excellent availability low wear to plant acceptable flocculant consumption low carbon footprint and low noise levels fully automatic.These features lead to simpler plant layouts, easier maintenance, smaller spares inventories, reduced wear, smaller footprint and overall lower capital and operating costs.The amenability of a particular tailing stream to treatment by screw press technology may be determined by test work. Two pilot plant studies are described where this technology has been applied in the mineral industry being flotation tailings from a rare earth (RE) mineral concentrator and coal tailings. In addition, preliminary details are given of an ACARP sponsored research program titled ‘The application of screw press filtration in tailings dewatering’.CITATION:Absolon, V J and Nieuwkerk, D, 2014. Innovative use of screw press filtration in tailings dewatering plant design, in Proceedings 12th AusIMM Mill Operators’ Conference 2014, pp 449–456 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 1, 2014

By P Chapman, B Moosapoor

The objective of this paper is to present the potential applications of geostatistical analyses in planning CPTu investigations, as well as interpolation of CPTu data. The paper presents a case study of a geostatistical analysis of CPTu data undertaken between 2004 and 2017 for an upstreamraised TSF located in the Goldfields region of Western Australia. An initial model is developed using the 2004, 2009 and 2017 CPTu data. The model is used to predict in situ cone tip resistance (qc) measurements, as the interested primary variable, at the selected locations where 2019 CPTu were undertaken, and the results of the prediction and the actual data are compared.

Jul 1, 2021

By A K. B Chigwada

Mining organisations grapple with the same problems year after year, wasting incredible amounts of time and money. According to estimates from the International Labour Organization (ILO), over one million work-related deaths occur annually, and hundreds of millions of workers suffer from workplace accidents and occupational exposure to hazardous substances worldwide. Many accident reports cite human failure as a primary cause (Busse and Johnson, 1998). The workers at the Bhopal chemical plant pumped methyl isocyanate into a leaking tank (Morehouse and Subramaniam, 1986). On 3 December 1984, more than 40 tons of methyl isocyanate gas leaked from a pesticide plant in Bhopal, India, immediately killing at least 3800 people and causing significant morbidity and premature death for many thousands more. The company involved in what became the worst industrial accident in history immediately tried to dissociate itself from legal responsibility (Broughton, 2005). Australia is not spared from safety problems either (Lucas, 2022). The ILO Convention 176 (1995) as a response provides that national law should inter alia provide for the supervision of safety and health in mines; the inspection of mines by designated inspectors of the competent authority; the procedures for reporting and investigating of fatal and serious accidents; the compilation and publication of statistics on accidents, occupational diseases and dangerous occurrences; the competent authority to suspend or restrict mining activities on safety and health grounds until conditions giving rise to the suspension are addressed; and worker consultation on matters related to safety and health in mines. This has assisted in getting enough data to define the magnitude of the problem to the mining sector.

Apr 16, 2024

By M Haest, O Dominguez, D Mittrup

Technological innovations and emerging analytical capabilities are transforming the way drill samples are analysed, with real-time mineralogical analysis made possible. In addition, new business/technical requirements are challenging long standing processes to incorporate more sources of information during planning in order to improve compliance to plan during mining and processing. Unfortunately, the new sources of information that are added do not always have adequate protocols in place to ensure quality data is collected.Spectral data covering the visible – near – short wave – midwave – longwave range are routinely collected by the Geoscience and Exploration department at BHP Billiton Iron Ore for accurate mineralogical identification. These data are used for geological interpretations (logging and modelling) and prediction of physical variables (metallurgical and geotechnical properties).This paper introduces how sampling and quality assurance / quality control concepts have been applied in the spectral data process. The described routine for sampling, data collection/management and reconciliation has been developed to track system precision and accurately and consistently ensure the data is of high quality before it is used across the mining chain.CITATION:Mittrup, D, Dominguez, O and Haest, M, 2017. A new approach to implement quality assurance and quality control to technological innovations – quality of spectral data capture and processes in the minerals industry, in Proceedings Eighth World Conference on Sampling and Blending , pp 265–270 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By K Watters

API Management Pty Ltd (API) is currently developing the West Pilbara Iron Project (the ‘Project’). The Project is a substantial greenfi elds mining and infrastructure development proposed for the west Pilbara region of Western Australia. The Project will establish API as a new and independent supplier of direct shipped iron ore. API manages the Australian Premium Iron Joint Venture (APIJV) on behalf of joint venture participants Aquila Resources Ltd and American Metals and Coal International Inc. The APIJV was formed in February 2005 with the objective of developing a long-term iron ore export operation in the west Pilbara region.Development of Stage 1 comprises a 30 million tonne per annum (Mt/a) channel iron deposit (CID) operation scheduled to commence in the second half of 2014 subject to approvals. JORC compliant CID resources total nearly 700 million tonnes and the Stage 1 mining area comprises eight iron ore deposits located between 30 km and 85 km south of Pannawonica. Run-of-mine ore from the eight deposits is transported to a central processing facility for crushing, screening and blending into a sinter fines product, which API has named West Pilbara Fines or WPF. Construction of a 282 km main line heavy haulage railway from the Stage 1 mining area to the proposed greenfields multi-user port at Anketell Point near Wickham, is capable of accommodating large Capesize bulk carriers and providing export facilities for other third parties. Capital investment in the order of $A6 billion includes essential support infrastructure including power, water, accommodation, roads and an airport at the mine.A feasibility study for the development of the Stage 1 mine, rail and port infrastructure has been completed along with environmental surveys of the mine, rail and port areas with Public Environmental Reviews (PERs) for each submitted for public review by end 2010. Consultation and cooperation with various stakeholders of the Project areas, and early engagement with traditional owners of the respective areas has commenced. Various sampling and metallurgical characterisation programs combined with independent institute and steel mill based testing have confirmed the positive sintering characteristics of WPF ore, which is higher in alumina (3.37 per cent) than typical Pilbara ores. *This is an abstract only. No paper was provided for this abstract.*

Jul 11, 2011

By S Garnes, W Austerberry, S Fraser

Despite significant investment in safety in the mining industry (mostly focused on processes and systems), many companies are unable to sustain and further improve their performance resulting in continued workplace incidents. The problem persists despite the best efforts of companies and allocation of resources to achieve Zero Harm. A DSS survey in 2019 found that two out of five companies that cannot manage risks and face disaster, leave the market within five years. All safety/risk management systems have the common steps of risk identification, prioritisation, design of controls consistent with risk tolerance, and verification of implementation/operability of controls. This is then complimented with improvement to one or more of the above elements through learnings obtained from incident investigations. In principle, the above process should work to reduce risks to, and keeping them at, a risk level consistent with risk tolerance in the organisation.

May 5, 2022

By J Maxlow, M J. Woods, M P. Sandy

The Newcrest Mining Limited Telfer operation comprises both open pit and underground operations producing gold and copper. The underground operation is made up of three production areas, the sublevel cave (SLC), M Reefs narrow vein open stoping and Western longhole open stoping areas. With stoping situated on the abutments of a mature and active sublevel cave, the interaction between mining areas is often complex. This is particularly evident in the M Reefs orebodies with high levels of extraction in all four reefs, and reliance on pillars to maintain local and global stability. A key concern was the potential for a cascading pillar failure to develop and rapidly progress through the M Reefs stoping area. The monitoring plan needed to capture any change in overall stability and identify if deformation was caused by pillar failure within the M Reefs and hanging wall closure, or shear on the reefs caused by SLC influence.

Nov 29, 2022

By G McCullough, B Mutsaers, J Jessop

"*This is an abstract only* Geometallurgical initiatives have demonstrated considerable value to operations that have trialled them. However, it is extremely difficult for these initiatives to become properly embedded into the operations and for that value to be realised on an ongoing basis.This paper will explore some of the historical reasons why this is the case. Some of these reasons include the limited tools available to manage an integrated operation. These, in turn, have resulted from poor communications infrastructure, inadequate sensor capability and the way technical mining software has evolved over the last 30 years.This paper will then investigate how the evolution of technology in recent years can help overcome these constraints and compare progress with similar industries.CITATION:McCullough, G, Mutsaers, B and Jessop, J, 2013. Obstacles to embedding geometallurgy decision-making into operations and how to increase maturity of this critical capability, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013, pp 139-140 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 29, 2013

By L MacDonald, D Molver, D Pepper

Increasing contamination/impurity levels (including arsenic, antimony, mercury etc.) of concentrates is an issue of global commercial and health / environmental significance. With increasing environmental pressures at smelters, penalties for contaminants in concentrates continue to rise, accompanied by lower reject limits. There is a strong incentive for miners to investigate alternative means to remove contaminants in order to increase the value of complex ores and concentrates. This paper discusses the global problem of contamination in complex ores and concentrates, how the Toowong Process technology is a potential solution to this problem, and the opportunities this technology brings to the business of dealing with deleterious elements. CITATION: MacDonald, L, Molver, D and Pepper, D, 2018. The Toowong process for treatment of complex ores, in Proceedings Complex Orebodies Conference 2018, pp 119–121 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By M Slight, H Lacy

In recent times, with the global mining industry’s focus on sustainable development there has been a significant focus on mine closure and rehabilitation performance and reporting through the development of the International Council on Mining Metals (ICMM), the Global Reporting Initiative and the Equator Principles. In addition, financial reporting obligations under International Financial Reporting Standards and the Sarbanes Oxley Act (2002) have also led to better understanding and improvements with industry closure performance, liability management and reporting.Under these sustainable development principles and financial reporting obligations, mining companies are required to consider mine closure planning and associated cost estimates across all life cycle phases of the mine. Internal processes have been developed within mining companies to better understand their closure liabilities and obligations and likely costs and cost estimating processes are generally developed for long-term life-of-mine (asset) planning and budgeting, financial reporting for corporate balance sheet provisioning purposes, and regulator reporting for environmental bonding and financial assurances.These days mining companies need to plan for, prepare and actually mine for closure right from the start of a project. This means that their closure and rehabilitation liabilities throughout each stage of the mine life cycle phases must be understood, planned for, managed and controlled.So how is the industry performing? Understanding of closure liabilities is improving and reflected in liability cost estimations that are recognising the likely issues to be faced at closure, but there is a way to go to ensure that the industry doesn’t add to the increasing legacy liabilities being passed onto the wider community.CITATION:Slight, M and Lacy, H, 2016. Closure liabilities – where are we at?, in Proceedings Life-of-Mine 2016 Conference , pp 28–30 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By M Liang, C Putzmann, D Gokaydin

The mining industry faces numerous challenges in swiftly evaluating and exploiting new mineral deposits to meet the escalating demand for critical minerals and metals. These challenges necessitate the adoption of innovative techniques and technologies to expedite development cycles and facilitate the efficient exchange of knowledge and expertise. Traditional mineral exploration methods rely heavily on data governance, visualisation tools, and expert interpretation skills, often operating in isolation and limiting the integration of valuable data and knowledge (Lindsay and Perrouty, 2019). To address these integration challenges and bridge the industry’s knowledge gap, the concept of a digital twin offers a holistic solution (Ahn, 2021; Nagovitsyn and Stepacheva, 2021).

Sep 1, 2024

By P J. Bangerter, J Pan

Optimising for Net Present Value (NPV) with a strategic optimiser such as COMET, Prober-E, Blaser or Minemax has hitherto lacked a dynamic method for analysing the so-called third-order outcomes (such as Carbon emissions) of optimisation within life-of-mine planning. Optimisation, per se, has natural effects on carbon emissions in a life-of-mine plan. Contemporary strategic planning employs a mathematical optimiser to make sense of non-linear data (ie a block model) and produces a best-NPV optimised mining schedule, within a set of constraints. The very act of optimisation influences emissions, and in a dynamic way.

Aug 2, 2023

By D Maconochie, S Pradhan, M Reed

The Waterview Connection will provide a high-quality strategic alternative to State Highway One and complete Auckland’s Western Ring Route connecting State Highways 20 and 16. The project includes twin three-lane motorway tunnels 2.4 km long and 13.1 m internal diameter (ID). The tunnel construction started in November 2013 using the tenth largest earth pressure balance (EPB) tunnel boring machine (TBM) in the world. The tunnels will pass beneath urban and greenfield areas as well as a major local arterial road. The project is being delivered by an alliance of constructors, designers and the New Zealand Transport Agency. This paper describes some of the key innovative and cost saving design solutions that have been achieved through collaboration in the alliance environment with the construction team, owner’s verifier, the segmental lining precast suballiance and the M&E suballiance for the underground works. The key design elements of the tunnel comprise a three-lane roadway, invert culvert and backfill, precast segmental lining, sixteen mined cross passages including a low point sump cross passage and steel segments for opening to the cross passages. This paper reviews interdisciplinary design integration and the economies achieved in the permanent works tunnel lining design, including reduction in lining thickness and optimising reinforcement, cross passage separation of 150 m, efficient design of the invert culvert and backfill design, main drainage pipe and low point sump. The paper also describes the attributes of the TBM and the invert culvert construction methodology.CITATION:Pradhan, S, Maconochie, D and Reed, M, 2014. Tunnel design in an alliance for Waterview Connection, New Zealand, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 425–430 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By W Y. Guo, L X. Chen, D X. Zhang

To obtain the rock type-I crack propagation process accurately, a novel fixture is used to make the prefabricated crack of rock propagation along the predetermined direction. In this study, the crack propagation process of rock is monitored with the digital image correlation method (DICM), and a mechanical model of crack directional propagation was established. The results show that the simple crack directional propagation device can effectively realise the stable propagation of type-I crack along the predetermined direction, the crack initiation angle is less than 10°, and the deviation between the peak strength of crack propagation calculated by a simplified mechanical model and the tensile strength of Brazilian splitting is 22.76 per cent and 7.53 per cent, respectively. According to the deformation field evolution law, crack propagation can be divided into three stages: microcrack development, main crack propagation, and main crack propagation. As for the rock type-I crack initiation and propagation mechanism, before reaching the peak strength, the prefabricated crack tip is subjected to maximum tensile stress; the elastic energy increases rapidly, and the dissipation energy increases slowly; after the peak strength, elastic energy exceeds its energy storage limit and released rapidly, and most of the input energy is converted into dissipation energy, which makes the crack propagation rapidly. The crack directional propagation device will be further optimised and improved, and it is expected to provide a new method for the study of crack propagation mechanism, rock failure precursor information and crack arrest principle, etc. It will also provide theoretical references for the optimisation of coal strata directional blasting, fracturing, fracture arrest, and other related technologies in geotechnical engineering.

Nov 29, 2022