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By D T. Ribeiro, J F. C L Costa, J C. Koppe

Drilling and sampling are responsible for most of the costs during mineral exploration, especially in multi-elements and polymetallic deposits, such as iron, manganese and bauxite deposits. On these deposits, often it is necessary to estimate multiple attributes at several granulometric fractions, ie distinct particle sizes. This paper investigates the effect of sampling at a close spacing grid only the head grades for the multiple chemical species in iron ore deposits. The remaining required data at the various grain sizes are sampled at a sparse grid. The derived geological model is checked for precision and accuracy comparing the output obtained against a model obtained using a complete isotopic data set including head grades and chemical analysis at each granulometric fraction analysed at all sampled positions. Among the several tested alternatives, the best procedure for dealing with the posed problem involved utilising the correlation coefficients between the grades at distinct fractions to obtain an isotopic database prior to interpolation. Cokriging was the method used, based on the intrinsic coregionalisation model. Estimates were obtained with the quality needed for the proposal of the study. Results showed that at least 50 per cent of the blocks were estimated with errors less than ten per cent relative to the grades obtained at the reference model, using only 15 per cent of the granulochemical data employed to obtain the reference model. The methodology also preserved the correlations between the attributes in their several granulometric fractions on the estimated model.

Sep 26, 2011

By B Stump

Reliable particle size analysis in minerals processing plants is a critical factor to the economic return of a plant. As recovery of valuable minerals is compromised for particles outside the optimal size range, effective and reliable particle size analysis is more crucial than ever, particularly in the current upswing of the global commodities market. Inefficient particle size analysis can lead to excessive over-grinding, thereby significantly increasing energy consumption and reagent costs, whilst negatively affecting process operation, thickening capacity, water recovery and tailings disposal.Australia’s first installation of a particle size analyser in Iron Ore has been monitored with great interest by the industry. Previously, manual size sampling at Rio Tinto’s Paraburdoo fines processing plant involved off-site sample analysis, with a turnaround measured in days. The Outotec PSI® 500 particle size indicator, commissioned in July 2009, takes approximately three minutes per line at site.The paper will include details on the following:• plant description,• sampling design,• PSI® 500 analyser functionality description, and• key learnings from site.

Jul 11, 2011

A Feasibility Study to determine the future of ZC Mines was completed in mid 1987. Early in this study, which lasted two years, it was identified that significant reductions in treatment costs would result if the Zinc Corporation Concentrator was closed. All of the production from the existing two mines, The Zinc Corporation Limited (ZC) and New Broken Hill Consolidated Limited (NBHC), would then be treated in the concentrator at NBHC.After a partial upgrade of the NBHC concentrator, the ZC concentrator was finally closed and all of the equipment disposed of. This closure highlighted the need to concentrate all ore haulage in one shaft to further reduce operating costs and remove the cost of surface transport of ZC production to the improved NBHC concentrator. This paper outlines the changes that were made to improve the haulage system for ZC Mines. After a number of options were investigated, it was finally decided that the upgrade of the existing NBHC haulage shaft was the best option even though some production would be lost while the upgrade was in progress.

Jan 1, 1988

By M J. Thurley, M Wimmer

To assess the present-day functionality of large-scale sublevel caving at LKAB Kiruna a comprehensive measurement program was undertaken involving blast function, fragmentation and gravity flow. As part of this assessment, a fragmentation measurement trial was performed based on 3D imaging of the drawpoint and corresponding bucket load of the underground load-haul-dump (LHD) excavator. 3D image data from stereo photogrammetry was collected and an automated image analysis strategy developed. A number of data sets were collected for each of the drawpoint and LHD bucket, along with sieving results for four of the LHD bucket loads (totally about 70 t). Two of the sieving results were used to inform the automated image analysis strategy, and two were held back as a comparison. Large variations in the visible particles are apparent when comparing corresponding drawpoints and LHD buckets highlighting the impact of sampling location and the need to measure large quantities of data in order to avoid bias from small samples. The results show that 3D imaging and analysis can produce fully automated measurement and analysis of the visible particle size distribution. Although this is not the same as the sieve-size distribution it provides useful estimation of both the larger size classes and a bulk estimate of fine material below approximately 60 mm. The 3D stereo photogrammetry measurement system used produced very high 3D point density but this was achieved using a custom up-sampling technique which significantly smoothed the data, removing small particles, smoothing edges, and this negatively affected the particle delineation algorithms.CITATION:Thurley, M J, Wimmer, M and Nordqvist, A, 2015. Blast fragmentation measurement based on three-dimensional imaging in sublevel caving drawpoints and underground excavator buckets at LKAB Kiruna, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 763–774 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By Hartley JS, Wills KJA

The Thalanga massive sulphide deposit is hosted by Upper Cambrian rhyolites and volcaniclastics of the Mt. Windsor Volcanics near their contact with overlying dacites, rhyolites and sediments of the Trooper Creek Formation. The ores and host rocks have been subjected to a single strong deformation and to lower to middle greenschist facies metamorphism. A main lens with surface gossan dimensions of 55U m x 6 m dips steeply, plunges shallowly to the west and is offset by a series of normal faults. It is flanked by smaller lenses to the east where the mineralized horizon is stopea out by granite. The area to the east and south of the gossan is masked by Tertiary cover. A complex exhalite package is represented by banded sphalerite-pyrite- galena-chalcopyrite, massive pyrite and chalcopyrite and assemblages dominated by dolomite, chlorite-actinolite, tremolite, talc, barite and rare gypsum. Accessory tetrahedrite, arsenopyrite, bismuthinite, magnetite and native gold are associated locally. Pods of quartz-magnetite formed distally. The ores are underlain by strongly to moderately pyrite-silica-sericite altered rhyolites with the strongest alteration closest to an interred synvolcanic fault. This alteration is characterised by an enrichment in MgO, Na2O, FeS2 and base metals with a depletion in CaO and Na2O. There is a general enrichment in Pb and Zn towards the hanging wall with some enrichment of Cu near the base of the main lens due to replacement by ore tiuias near vent discharge sites. Zonation of Cu to 2n-Pb in also evident over narrow intervals

Jan 1, 1987

By G Wyartt

In the Pilbara region of Western Australia, an iron ore mine is undertaking a high wall cut-back to improve stability and allow access to deeper ore deposits. Several sections of the wall have been classified low factor-of-safety due to unstable localised geology, and therefore an engineered approach to vibration critical blasting was required. The use of electronic detonators allowed multiple signature (seed) holes to be incorporated into a production blast adjacent to the low factor-of-safety area, therefore providing baseline vibration data to be used for future modelling with the added advantage of eliminating unnecessary pit closure downtime typically associated with a signature hole program. All subsequent blast patterns also incorporated multiple signature holes to provide additional data and allow continual updating – and therefore improved accuracy - of the blast prediction model. Electronic detonators and blast initiation systems were combined with advanced blast vibration modelling software to produce optimal timing sequences with predictable vibration outcomes. Although minimising vibration was the primary focus, blasting induced frequency was also a concern for the project team and therefore initiation sequencing was optimised to also avoid undesirable frequencies. Minor variations in ground factors (vibration transmission and attenuation) were noted, and therefore justified the inclusion of regular signature holes which allowed continual vibration model updates. Blasting results produced vibration and frequency measurements within allowable limits and closely resembled the predictive model. These positive results were achievable through the combination of electronic detonators, advanced modelling software and good onsite practices by engineering and on-bench teams alike. This project will remain ongoing as the pit progresses to deeper benches, and therefore the same methodology will be applied; quality and continual data collection, the use of electronic detonators, and optimisation via advanced vibration and frequency modelling software. CITATION:Wyartt, G, 2018. Vibration control blasting for low stability final walls, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 504–510 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By F Phillips, E Deucker, J Kato

It is challenging to determine the optimal mining strategy to maximise value when a mine plan includes mineralised material which does not meet the full cost of mining but has value exceeding the variable cost of mining (‘marginal material’). Mining too much marginal material dilutes the operation’s head grade and undermines profitability. Conversely, leaving too much metal behind fails to achieve the full value of the endowment. Finding the balance between the two will maximise value delivered from the asset. This dilemma has traditionally been approached by calculating a suite of cut-off grades to define the grade of material that meets economic targets for an orebody (or zone within) and should therefore be included in the mine plan. A problem with this approach is that individual mining blocks within the zone have different costs, value and confidence levels, with each having economic co-dependencies between them. Blocks of identical grade but different mining contexts will have distinctly different economic outcomes. For example: • a block may be a low-grade increment or shell around a higher-grade stope; • a block may be available to be mined when there is spare mining capacity; or • a block may defer access to significantly higher cash flow material. Each of these circumstances would result in different value from the blocks if included as part of the mine plan. Cut-off grades calculated as averages over zones of material, or in isolation from schedule-based information, are missing the entire mining context that determines the ultimate economic outcome of making a mining decision. There are tools and techniques available to address this for open pit mining, however underground mining has different nuances. There are more intricate economic and physical dependencies between potential ore blocks, and importantly, the decision to leave material in situ can be made at any time. The case study in this paper explores a new methodology for underground mining, targeted towards strategic planning applications. It examines whether the economic logic usually applied via cut-off calculations can be implemented in the schedule so that optimal economic decisions can be made on a block-by-block basis, taking into account the mining context of the block, with the objective to maximise asset value. The results of the case study scenarios in Table 1 demonstrate the magnitude of the potential improvement in NPV that can be attained by a block by block valuation approach

Mar 15, 2021

By T Purvis, J Calverd, A-K Greve

The Ernest Henry Mining (EHM) underground mine is situated adjacent to the Great Artesian Basin in North Queensland and within a fracture zone. Underground development commenced in February 2008 and has extended to approximately 1000 vertical metres below the surface.Groundwater has been encountered in numerous locations throughout the mine, predominantly on the eastern side of the orebody and often related to fault structures. Most of the groundwater encountered has been managed with conventional pumping systems; however, on occasions large water inflows have been encountered, which have had a significant impact on the planned development of the mine. Some of the intersections encountered had the potential to compromise the mine from a combination of high temperature (over 45°C), high pressure (3500 kPa) and high flows (50–100 L/s).This paper describes three case studies where significant water inflows were encountered and then controlled by the injection of cementitious grout into the rock mass. The case studies are the 1650 mid-shaft heading, the 1325 shaft access decline and the 1625 to 1475 fresh air rise (FAR) raise bore. Each case study includes a brief description of the event that occurred and the grouting equipment and techniques developed to enable mining to continue.The paper also describes the development of a hydrogeological map of the mine, the probe-hole regime used for high-risk headings and the required processes and systems to inject both cementitious grouts and polyurethane resin into the rock mass.CITATION:Purvis, T, Calverd, J and Greve, A-K, 2014. Management of high-pressure groundwater in underground development at Ernest Henry Mine, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 217–226 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

By A G. L Pratt

Operational readiness is a commonly used term in mining and many other industry settings. However, translating this term into a coherent scope of work that is practical and meaningful is a challenge faced by many mining projects. This inhibits the allocation of resources to the work and its completion. The problem is with understanding how the terminology applies to establishing a mining operation. Resolving this problem requires clarity around what operational readiness means for a mining project’s transition to operations and who owns the tasks of completing operational readiness. The motivation for resolution of this problem is in appreciating the consequences arising from any lack of clarity in definition of this task, the timing of the work, and ownership for its completion. In broad terms, these consequences amount to an erosion of value at a critical time for both the new mine and the company and shareholders. This situation often arises where operational readiness is not adequately addressed in project’s study phases. As a result, neither time, resources nor money are adequately provided to complete the work required. In other cases, operational readiness is sometimes assimilated with the delivery of the project’s physical assets by the project’s construction team, rather than aligned with the establishment of the operating team to deliver the desired operational outputs. This paper argues that operational readiness starts in a project’s study phases and flows through into the start of operations. The definition of operational readiness is discussed as a task, and a model for its planning and completion is presented. This discussion includes assigning ownership for operational readiness planning and delivery to the General Manager of a new operation and the operations leadership team, who are central to the success of this work. After all, the reputations of this leadership team depend on the performance of the operation in its first few years. The author’s work over the last 20 years, leading operational readiness programs and the preparation of feasibility studies for mining projects, has provided the insights and evolution of ideas that are central to this paper. Operational readiness is fundamentally directed at ensuring a new mining operation gets away to a successful start and builds a solid foundation for the future of the mine/operation/province. It requires clarity of purpose, ownership and coordination by people in the operating team, and their preparation of the requisite process definition and establishment of the significant relationships required for operations. Without its successful completion, it is unlikely the new operation will meet and sustain its start-up targets. This paper discusses a practical approach to operational readiness for mining projects.

Mar 29, 2023

By J Wheeler

The objective of this paper is to examine the operation of high frequency screens in closed circuit grinding, where the outcomes achieved indicate favourable economic gains at the comminution stage and downstream processes, including flotation, dewatering, and filtration operations. The classification process in grinding circuits has been slowly evolving within the last century. The history of classification devices brings to mind rake classifiers and spiral classifiers, which although having higher efficiencies compared to hydrocyclones, were not able to keep pace with the evolution of concentrator equipment treating higher tonnages. This higher tonnage throughput has tended to drive the concept of utilising hydrocyclones as the classification stage in closed grinding circuits. The comminution process is commonly the most energy intensive stage of mineral processing. Researchers have determined that the classification stage in the comminution process has the greatest potential for improvement. This paper is intended to inform mineral process engineers of the benefits that high frequency screens offer over hydrocyclones. This will be done by reviewing the purpose for the evolution of classification in the comminution process, documenting past and recent studies, and explaining the modern technology that is currently available.

Aug 8, 2011

Barrick Gold Granny Smith Mine is currently undergoing conversion from an open cut operation to an underground mine at the Wallaby deposit. The underground project commenced in 2005 with the development of the reserves immediately below the pit and is now currently entering a production ramp-up phase for mining of these two initial surfaces below the pit. With increasing gold prices the owner has been forced to re-evaluate the underground project and has decided to investigate the potential of a deep level mine. This deep level underground mine presents a collection of challenges with the most notable being exploitation of a series of well separated near horizontal lodes ranging in thickness from less than 1 to 20 m. A variety of room and pillar mining methods are employed for extraction with careful consideration to resource recovery and pillar design for long-term stability. Compounding these deep level challenges is a need to accelerate mine level development to maintain the production profile of the mine. This paper describes the challenges, key learnings and outcomes of the studies undertaken to date associated with this project.

Jan 1, 2008

By M Sciortino, J Korczak, J Muinonen, A St-Jean

The Dumont deposit is a large (1179 Mt reserve), low-grade (0.27 per cent nickel) nickel sulfide project located in the Abitibi region 25 km west of Amos, Quebec. Royal Nickel Corporation (RNC) acquired the project in 2007 and has since taken the deposit through to feasibility. The disseminated nickel sulfide and alloy mineralisation is hosted within the serpentinised dunite subzone of the Dumont Sill; a differentiated, pervasively serpentinised, ultramafic sill of komatiitic affinity. Pentlandite ((Ni,Fe)9S8), heazlewoodite (Ni3S2) and awaruite (Ni2.5Fe) are the dominant nickel-bearing metallic phases and can be recovered by conventional methods (flotation, magnetic separation). Non-recoverable nickel is also present within serpentine and olivine of the silicate matrix.A detailed mineralogical program including 1420 QEMSCAN« samples and 4400 electron microprobe points was undertaken to increase the understanding of the nickel deportment in the various recoverable and non-recoverable phases in a spatial context across the deposit. A total of 105 metallurgical tests have been performed under a standard procedure which have linked the mineralogy to metallurgical performance. This has allowed the creation and modelling of geometallurgical domains on a block-by-block basis to understand the recovery variation and metallurgical performance throughout the deposit. Understanding the spatial variability of Ni deportment in recoverable and non-recoverable phases through mineralogy is the key to understanding metallurgical performance, thus unlocking the value of the Dumont deposit and other large tonnage low-grade ultramafic nickel deposits.CITATION:Sciortino, M, Muinonen, J, Korczak, J and St-Jean, A, 2013. Geometallurgical modelling of the Dumont Deposit, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 93-100 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

By A Lyon

The minerals industry, as many other industries, has a wealth of indicators and a thriving æindustryÆ in their development, measurement and reporting. It is natural for this to occur for a new endeavour. However, perhaps it is time for the community concerned with minerals industry indicators to ask whether we have achieved a certain maturation whereby proliferation of indicators may be replaced by a more disciplined and constrained approach. In many natural and engineered systems, thermodynamics provides well-understood and tested constraints. Indicators that are uninterpretable in this framework are not considered acceptable. This paper provides initial evidence that such a formalism may be possible for mine sustainability. The formalism developed does not claim to have the rigour of thermodynamics. However, it does provide a first step towards formalising selection of indicators on the basis of their true comprehensibility. A set of simple equations is developed that represent the conventional five capitals (actually we use six because we separate renewable and non-renewable natural capital) and how they are linked. This is coded into a simulation model. The base equations are then used to develop a system level indicator of sustainability performance, which is asserted to be a reflection of the mineÆs reputation. We define a least sustainable state, termed æmaximum revenue mining (MRM)Æ in the system and define the degree of system sustainability as how far the system is from the MRM. We then introduce a simple mechanism whereby different actors can express differing views on the emphasis for the distance from MRM. Sustainability thereby becomes a non-unique thing that is defined by a distance from MRM and a set of preferences across the capitals.

Jan 1, 2009

By B Wu, B W. Lei, B J. Duan

When a coalmine fire occurs, it is crucial to judge the developing trends inside the fire area by analysing the changes of gas concentration in order to formulate the proper rescue measures. At present, few researchers have focused on the relationship between the changing trend of gas product and basic characteristics of fire in the coal fire extinguishing process. To study the relationship of basic characteristics of coalmine fire during the extinguishing process, an experimental platform for coal combustion in a confined space was built, and gas production, flame image and coal temperature during the extinguishing process were monitored and analysed by an online continuous gas analysis instrument, camera and thermocouple. Research shows that during the burning phase of the coal sample in the confined space, the flame zone decreases gradually due to insufficient gas supply. The size of the flame zone fluctuates and shares a positive correlation with CO concentration, while sharing a negative correlation with O2 and CO2 concentrations. Then, in the extinguishing phase, the increasing rate of CO2 concentration and the decreasing rate of O2 concentration both decrease gradually, but CO concentration would rise for a period before it eventually decreases. Coal temperature continues to rise in the open flame stage and does not go down until the flame is extinguished.CITATION:Lei, B W, Wu, B and Duan, B J, 2015. Experimental study on extinguishing characteristics of coal fire in confined space, in Proceedings The Australian Mine Ventilation Conference, pp 279–284 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By J Missen, P Currie, J Bohan, D Clark

AGL is one of Australia’s leading integrated energy companies and the largest ASX listed owner, operator and developer of renewable energy and thermal generation in the country. AGL owns and operates the 2210 MW Loy Yang A power station and adjacent 30 Mt/a brown coalmine in the Latrobe Valley, Victoria. It also supplies coal to the nearby 1050 MW Loy Yang B power station owned by the GDF Suez (Engie)/Mitsui partnership. The mine is currently nearly 5 km long, more than 2 km wide at the operating face and up to 200 m deep. AGL employs a large workforce at Loy Yang and a substantial amount of services are performed on-site by contractors and consultants.GHD provides mine planning, earth sciences, civil/geotechnical engineering, dam surveillance, plant engineering and environmental services to AGL Loy Yang through an alliance framework. GHD is one of the world’s leading professional services companies operating in the global markets of water; energy and resources; environment; property and buildings; and transportation. In addition to GHD’s global footprint, the company also has a significant Victorian presence, including a permanent, well-resourced regional office in Traralgon, approximately 10 km from Loy Yang, as well as a permanent site office.A joint paper on the Loy Yang mine professional services alliance model was written for the AusIMM International Mine Management Conference in 2006 by Woods and Wood. Now ten years on, this paper provides an overview of the present relationship and arrangements, including the continued transformation of the alliance model and maturing of the relationship contract.These are challenging times, with increasing cost and regulatory pressure driving change in the broader energy and resources industry, and locally including both the mining and power sectors at Loy Yang. Flexible models to achieve a balance between internal personnel and access to key external skills, whilst achieving value for money and transparency, is increasingly critical. The right drivers and performance measures are essential, particularly when confronted with potential major technical and environmental risks (considering significant ground failure and fire events that have occurred elsewhere within the Latrobe Valley over the last decade) within a sector that is reducing costs and optimising production.This case study discusses the alliance status and changes, reasons behind adjustments and what the future is likely to hold. The paper also explores the validity of the original objectives and the extent to which they have been achieved. The philosophy of the alliance is to continue closely aligning the objectives of the two companies in the best interests of the Loy Yang site and immediate surrounds/stakeholders. Quality of service, costs, timeliness, health and safety (H&S) and some operational activities (aquifer depressurisation) remain important aspects and are reflected in key indicators for which performance is measured.CITATION:Clark, D, Bohan, J, Currie, P and Missen, J, 2016. AGL energy, Loy Yang and GHD – a further case study in alliancing: ten years on, in Proceedings International Mine Management Conference, pp 321-330 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 22, 2016

By A L. de Ambrosis, S J. Clarke, R Bertuzzi, J Redelinghuys

The M2 Upgrade Project involved widening 15 km of the existing M2 Motorway, which is a key route in Sydney’s road network. The Norfolk Twin Tunnels in North Epping convey traffic over a 460 m length of the motorway. The project involved widening the twin tunnels to provide a third lane and breakdown lane in each direction.The widening of the tunnels was fundamentally different to other ‘greenfield’ tunnel projects in that the operation of the tunnel was maintained throughout construction, with motorway traffic permitted close to the excavation faces on a daily basis. The widened works had to integrate with the existing tunnel support, construction details, and mechanical and electrical infrastructure.The existing tunnel afforded the opportunity to review existing ground conditions in the tunnel. Exposures were mapped within the tunnel, and key design parameters were back-analysed from the original monitoring data to provide increased confidence in the assessed impact from the widening works.Traffic capacity of the tunnels was maintained by detailed staging of the works, and included the ability to reopen the tunnels at short notice.A permit to tunnel system was developed to manage the risks associated with re-opening the tunnel to traffic. A comprehensive suite of instrumentation was maintained to provide reliable monitoring data to support this process. Emphasis on the robustness and reliability of tunnel instrumentation provided increased confidence in the adequacy of the tunnel support being installed. The monitoring was routinely compared with design predictions to check the adequacy of the support measures being installed and confirm the design.The approaches and methodologies developed for the widening of the Norfolk Tunnels were effective in maintaining the safe operation of the tunnels throughout the two years of construction, and provide a framework for increasing the capacity of existing tunnel infrastructure in the future.CITATION:Clarke, S J, de Ambrosis, A L, Bertuzzi, R and Redelinghuys, J, 2014. Design and construction for the widening of the M2 Norfolk Twin Tunnels, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 591–602 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By M Barker, H Li

The total number of tailings accidents has reduced from over 50/decade in the 1960s-1980s to less than 30/decade in the 2000s to 2010s. However, the rate of significant tailings dam failures has not been reduced. The significant tailings dam failures the mining industry experienced in the recent history include: Merriespruit, South Africa, 1994; Los Frails, Spain, 1998; Kolontár, Hungry, 2010; Mount Polley, Canada, 2014; and Samarco, Brazil, 2015. The conventional Factor of Safety approach itself may not be enough to further reduce the rate of significant tailings failures due to its limitations such as uncertainty. For example, the same factor of safety could have a vast range of annual probability of failure for different tailings dams, and insufficient consideration of failure consequence. This paper presents a risk based approach for design with the objective being to minimise tailings dam failures, especially those significant tailings failures with high consequence and low probability. This approach includes risk based design and risk management using bowtie tools. In the risk based design, quantitative analysis will be used to estimate the annual probability of failure and the tolerable failure criteria is linked to the consequence category. Bowtie analyses will be used to understand hazards and risks and identify and select independent controls that are effective in preventing and mitigating catastrophic failures. In this paper, examples of risk based design and bowtie analyses are presented and discussed. CITATION:Li, H and Barker, M, 2018. Risk-based approach for minimising tailings dam failures, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 397–414 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By A D. Wulfse, C M. D Barton

Underground fractured aquifers in the Ernest Henry deposit are to a large extent controlled by deposit scale brittle structures. The underground mine has been subdivided into nine water zones based on hydrogeological characteristics, including conductivity and connectivity, within the mining areas bound by these structures. The nine water zones and the hydrological characteristics of the associated structures are utilised for risk assessing mine development and for targeting diamond drilling dewatering activities. Wireline and conventional underground diamond drilling techniques have been used throughout the network of underground aquifers with the aim of dewatering areas within the mining footprint. These dewatering drilling campaigns have historically been highly successful at lowering aquifer water levels throughout the underground workings. As part of recent mine expansion activities, diamond drilling has intersected high pressure (>507 psi), high temperature (>50°C) and high flow water (>3 L/sec) in as yet unconstrained underground aquifers. Groundwater is typically conducted through rubble and clay rich faults, further hampering progression of drilling. Drilling through fractured aquifers at depth presents both mine planning as well as safety challenges. Recent drill holes have been delayed or abandoned when aquifers hosting this high pressure, high flow water have been intersected, risking mine planning deadlines. Recent technological innovation developed to control groundwater outflows from the diamond drill hole whilst drilling has been trialled at the Ernest Henry Mine. This case study focuses on the utilisation of alternative drill methodologies to allow the current drilling campaign to continue without delay, whilst also improving safety conditions encountered on the drill site.

Mar 22, 2022

By J Foster

The Lanfranchi Nickel mine is located approximately 48 km south of Kambalda in Western Australia. Mining first commenced in the mid-1970s under the previous owner, Western Mining Corporation Ltd. After two years on care and maintenance, Panoramic Resources (previously known as Sally Malay Mining Ltd) purchased the operation in November 2004. The site currently produces approximately 10?000 tonnes of nickel metal annually from approximately 430?000 tonnes of ore. The Ore is mined from four main orebodies; Deacon, Helmut South, Lanfranchi and Schmitz. The Helmut South orebody is situated approximately 790 m below surface and extends to a resource depth of 940 m. Horizontal thickness of the orebody ranges from 10 m to 45 m in width, with the average being 30 m. Previous mining at the Lanfranchi operations specifically the Helmut orebody, had a history of seismic activity. When Panoramic Resources acquired the operation it was decided that seismicity was going to be an issue and therefore a mining method needed to be selected that could effectively manage this potential risk. The dip of the orebody is quite shallow at 45º, with a 30º plunge to the south . The hanging-wall comprises of very weak ultramafics. Due to these factors the orebody posed several mining challenges. To safely and effectively mine the Helmut South orebody in the Lanfranchi Nickel mine, underhand cut and fill mining was selected as the most appropriate mining method. Paste fill comprising of cemented gold tailings was the backfill of choice. This paper is intended to convey some of the key learnings from the use of a mining method that has not been commonly practiced in Australia.

Mar 21, 2011

By M I. Pownceby, M A. Rhamdhani, S Palanisamy, D Fellicia, B Satritama, G A. Brooks, A Ang

Metal production have long been using carbon sources as both reducing agents and energy sources. Consequently, the global extractive metal sector contributes significantly to greenhouse gas emissions, accounting for approximately 9.5 per cent. Hydrogen gas offers as a promising ecofriendly alternative to carbon in metallurgical processes, serving as both a reductant and energy supplier with a by-product being only water vapour. However, the implementation of molecular hydrogen faces certain challenges related to the thermodynamics and kinetics of metal oxide reduction. In addressing these challenges, researchers have explored the application of hydrogen plasma, generated by subjecting molecular hydrogen to high energy to produce atomic, ionic and excited hydrogen species. Hydrogen plasma offers thermodynamic and kinetic advantages over molecular hydrogen and carbon-based reductants, exhibiting lower standard Gibbs free energy of reaction and activation energy. Therefore, hydrogen plasma can produce metal in fewer steps, process any oxide feed and feed size and even be used to refine metals. Despite these advantages, challenges exist in utilising hydrogen plasma in extractive metallurgy, including electricity costs, potential reverse reactions and industrial-scale implementation. This study provides a mini review of prior research on hydrogen plasma for metal oxides reduction, particularly iron oxide, as well as state-of-the-art techniques for its use in extractive metallurgy applications by mentioning several reactor types. Future prospects and scale-up possibilities of the hydrogen plasma in extractive metallurgy will also be presented.

Aug 21, 2024