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Minerals and Metals Group (MMG) Century mine (Century) is a large open-cut mine in northwest Queensland approximately 2.5 km long, 1.5 km wide and 240 m deep, with an ultimate pit depth of 320 m. In 2009, the mine experienced three failures which began as small failures, and progressively developed into significant multi-batter failures. The incidents were managed by a combination of analysis, redesign and practical management to achieve positive outcomes for the mine. On the south wall of the mine, a series of batter-scale wedge failures occurred in December 2007. Analysis of structure orientations and design changes aimed to minimise the risk of failure extending over multiple batters, while accepting a risk of further small-scale failures. Design changes were constrained by a culturally sensitive area (CSA) located south of the wall. As mining progressed, shallow wedge failures developed over multiple batters and cracks were observed 60m back from the pit crest, indicating that a large-scale wedge failure was developing. Movement increased in January 2009 as a result of significant rainfall. After considering several design options, the area was stabilised by a cut-back of the wall. Two multi-batter failures also occurred on the north wall as mining progressed through a structurally complex area. Both north wall failures began as small failures that progressively developed, and required a redesign of the wall below as well as practical management of safety aspects. The complex structural geology was difficult to predict ahead of mining, and required geotechnical input into design changes as mining progressed. All three failures potentially had significant impact for ore recovery, and were managed by a combination of analysis, redesign and operational management have resulted to achieve positive outcomes in a challenging mining environment.

May 1, 2010

By A Golsby

Gunite was invented in 1907 by Carl Akeley to repair a crumbling facade of the Field Columbian Museum in Chicago. The method used was to blow dry material out of a hose with compressed air and inject water at the nozzle as it was released. In 1911, he was granted a patent for his invention, the ‘cement gun’; the equipment used; and ‘gunite’, the material that was produced.The advantages of using the dry mix process is that the water content can be adjusted instantaneously, allowing more effective placement in overhead and vertical applications without using accelerators. The dry mix process is useful in repair applications when it is necessary to stop frequently as the dry material is easily discharged from the hose.This paper describes the applications and principles of the gunite pump system in underground coal mining and discusses why it is the preferred spraying system for both cement and plaster products.It also addresses improving productivity and examines dust, respirable crystalline silica (RCS) and health issues around gunite pump systems. The solutions include development of the latest componentry for current gunite pumps to improve their efficiency and allow their operation to be dustless.In particular, this paper addresses:why and where RCS is a problem in underground coal mininghow RCS hazards and its propagation can be managedhow the gunite pump system has become dustlesshow the gunite system has become more productivegunite occupational health and safety issues and how they have been solveda case study of gunite dry spraying.CITATION:Golsby, A, 2015. The development of a dustless dry gunite pump system in underground coal mining – a case study, in Proceedings The Australian Mine Ventilation Conference, pp 41–48 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By J Johansson, B Johansson

The mining industry needs to attract and recruit young talented people. An important task is, therefore, to create an attractive mining workplace that engages with, and motivates youngsters who are not particularly interested in working in the industry. This paper aims to illustrate a way forward for the mining industry to form healthy and safe workplaces honouring key components such as knowledge, skill, co-operation, continual development and acceptance of diversity. This is a way to create a vision of healthy and safe mining work. The mining industry must work towards zero vision; a future without accidents and hazardous environments. In this paper the authors discuss different aspects of an ‘attractive workplace’ and summarises lessons learnt in 26 statements dealing with safety, both physical and social work environments, and social responsibility. The authors hope these recommendations will provide some guidance for how attractive workplaces should be designed for future deep mining.The paper is based on lessons from two large European projects, a Swedish-Polish project: The Smart Mine of the Future; and a European Union project: Sustainable Intelligent Mining Systems (SIMS). One of the authors was the WP leader of health and safety in both projects.CITATION:Johansson, J and Johansson, B, 2017. Attractive workplaces in future underground mining, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 99–102 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017

By D Miller, M Dowling, R Domotor

"This paper is focused on blasting activities undertaken as part of the Pacific Highway Upgrade – Tintenbar to Ewingsdale – project (T2E). This is a ‘priority 1’ Pacific Highway road construction project in New South Wales (NSW), to be completed by mid-2015 (weather permitting). T2E will provide approximately 17 km of dual carriageway road starting at the northern end of the Ballina bypass and extending to the Ewingsdale interchange, and will complete the existing dual carriageway road between Ballina and the NSW/Queensland border.Roads and Maritime Services (RMS) (formerly the Roads and Traffic Authority) is delivering the project on behalf of the NSW state and federal governments. In October 2011, RMS awarded a contract to Baulderstone Pty Ltd (now Lend Lease Engineering Pty Ltd – Lend Lease) to design and construct T2E. One of the key elements in this project is the St Helena Tunnel.In order to avoid the steep grades of St Helena Hill, eliminate a well-known accident black spot and maintain the aesthetics of the Byron hinterland escarpment, RMS and Lend Lease prepared designs to construct a 434 m long dual carriageway tunnel, 46 m below the ridge line of St Helena Hill. Lend Lease elected, where geotechnical conditions permitted, to use drill and blast methods to excavate the full tunnel profile, instead of traditional mechanical excavation techniques.Since all blasting locations (both inside and outside the tunnel) were in close proximity to nearby residents, the NSW Department of Planning and Infrastructure imposed strict air blast overpressure (airblast), ground vibration (vibration) limits and limited working hours. Both RMS and Lend Lease recognised that these restrictions meant that nearby residents may be exposed to blasting activities for longer than was necessary. As a result, after close consultation and agreement with the nearby residents, RMS applied successfully to the NSW Department of Planning to increase the airblast and vibration limits, as well as the working hours.Working under these new conditions, Lend Lease employed a range of best practice drill and blast technologies provided by both Orica Australia Pty Ltd and Atlas Copco Mining and Rock Excavation to improve the safety and efficiency of blasting activities and to minimise the potential negative impacts of the blasting works on affected residents. These technologies included: the use of a continuous environmental monitoring system to record the results of the blast events and provide quick and easy reporting to key stakeholders to address RMS specification requirements electronic detonators to enable accurate hole detonation timing for vibration compliance and to give project engineers the flexibility and precision to alter each design to suit the geological profile of each face the use of two software programs and advanced drill rigs to enable the efficient design of blasts, electronic transfer of designs to the drill rigs, as well as in-hole monitoring and recording of drilling performance the use of a specialised bulk emulsion system to deliver fully coupled bulk explosives into face blastholes to maximise fragmentation, and decoupled bulk explosives into perimeter blastholes, to reduce overbreak and deliver a cleaner profile.By taking a progressive approach towards the environmental restrictions and the work hours imposed, as well as utilising best practice blasting techniques, RMS and Lend Lease were able to blast with confidence and achieve their production deadlines and reduce the total cost of the project.Most importantly, RMS and Lend Lease were able to meet their environmental obligations and work constructively with the nearby residents to ensure that the blasting was undertaken as safely and efficiently as possible without delay or negative impact.CITATION:Dowling, M, Domotor, R and Miller, D, 2014. Improving excavation efficiency at the St Helena Tunnel using best practice drill and blast techniques, in Proceedings 15"

Sep 17, 2014

By R Stead

So many ceramics look the same, but are they?In the past 20 years, there have been significant changes in the materials available, as well as changes to the supply chain, for ceramics used in wear applications in the hard rock mining industry. The biggest change in supply has been from the Chinese market, with many suppliers promoting their products as æstate of the artÆ. Some of them are state of the art, but are they all? There will be some concluding remarks in this respect.There are still some outstanding new developments coming from the more traditional suppliers and these should not be ignored. However, as an end user, how can one be sure that the product received meets the technical specifications of that material?This paper will address some of the questions on how to differentiate between different materials by giving a technical overview of the current (but not exclusive) range of popular ceramics, plus incorporating how these ceramics are used in process plant products by presenting case studies. The presentation will include technical data coupled with micrographs of various ceramics to illustrate just why they are different.It will also be shown that by careful selection of the wear material, it is possible to gain significant benefit when using superior materials in an ore processing plant. The impact of cost of the products, life, process efficiency, and reduced maintenance costs will be considered using cyclone components as an example.The properties (including the microstructures) of the various ceramics will be compared to the application in order to get some understanding of what is considered good or bad.Misra and Finnie (1982) summarised their paper, æA review of Abrasive Wear of MetalsÆ by saying:à it is difficult to give guidelines for selecting materials for abrasive wear resistance. Each application is a different one, and a design engineer has to take into account various other factors such as impact, fatigue and corrosion which are often coupled with abrasive wear. The same applies to ceramics.CITATION:Stead, R, 2013. Applications of ceramic wear materials in the gold industry, in Proceedings World Gold 2013, pp 325-330 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By J L. Macdonald, G S. King

"The development of a predictive geometallurgical model is a multidisciplinary and iterative task that involves both discovery and integration aspects. In this paper, the authors discuss the concepts of geometallurgical modelling in terms of the underlying relationships that are used to connect geology, metallurgy and economic value, and how the early-stage preparation of a spatial geometallurgical model enhances project value and provides a sound basis for future studies and test work programs.Hot Chili’s (copper-gold-molybdenum) Productora Project, which is located in northern Chile, is a porphyry-copper style deposit that can be exploited using open pit mining and preparation of a saleable concentrate from fresh ore, as well as heap leaching, solvent extraction and electrowinning (SX-EW) extraction of copper from oxide ores. To enhance project value in the Productora prefeasibility study (PFS), Hot Chili developed a geometallurgical model that was used to predict the process responses of both sulfide and oxide ores. The Productora model incorporates test results from mineralogical, metallurgical and comminution testing, as well as other studies completed on a suite of samples collected from the many geological domains of the deposit.Using Bond Work Index and Abrasion Index proxies in the geometallurgical model, Hot Chili estimated the variability of sulfide ore throughput and comminution costs. Heap leach acid consumption in oxide ore was estimated from drill hole calcium concentrations. The model was then used in mine scheduling to identify high and low throughput or high and low acid ore zones so that the processing of these zones could be advanced or deferred to improve net present value (NPV). Additionally, the cost benefits of preparing an early-stage geometallurgy model were quantified through a comparison to a conventional model that was based on test work averages.CITATION:King, G S and Macdonald, J L, 2016. The Business Case for Early-stage Implementation of Geometallurgy– an Example from the Productora Cu-Mo-Au Deposit, Chile, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 125–134 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By P Jonsén, S Larsson, M Parian, B I. Pålsson

The question of effective energy utilisation in grinding mills is not new. There are several conflicting arguments about tumbling mills, whether the efficiency is around 1 per cent or maybe 10 per cent, or even much lower. The energy not used is assumed to be lost as heating of the pulp, the grinding mill body, the charge, generation of shock waves and vibrations, etc. Stirred media mills on the other hand are generally considered to have better energy utilisation, but their energy efficiency is still not that clear. To shed some light on this a pilot-scale, wet stirred media mill was investigated over a range of operating conditions. The wet stirred media mill is a Drais PMH 5 TEX pearl mill fitted with an electric motor at 11 kW. It has been investigated over a range of operating conditions to try to balance the dissemination of the input energy in forms of the net grinding energy, mechanical energy losses, and the heating transferred to the pulp, the mill, the charge, and the cooling water. It is found that approximately 20–40 per cent of the input energy accounts for the grinding process. Also, that the difference between gross and net input electrical energy is mainly disseminated as heating of the pulp and cooling water. Mechanical energy losses appear to be much smaller than the heating effects. The use of a dispersant seems to mainly influence the heating effect.

Aug 24, 2022

By P Thompson, B W. Atkinson

Water treatment is not æcore businessÆ for mining companies.Just as mineral ores and coals are unique, each requiring detailed characterisation and pilot-testing to determine their optimum beneficiation route, so too are mine waters, each requiring careful assessment to determine the most appropriate treatment. There are many cases of æregret capitalÆ expenditure, whereby mines have installed off-the-shelf equipment only to find it inadequate for their purposes or grossly expensive and labour intensive to operate.Water may be required for potable purposes, ore processing, dust control and/or irrigation. A major driver will frequently be environmental constraints for off-site discharge. Mine water projects can become very complex, and detailed models need to be prepared and optimised to properly consider the raw water sources, the on-site storages, the on-site uses and the off-site discharges, as well as handling the residuals (by-products) of water treatment. By-products may be in the form of concentrated backwash streams or streams of elevated salt content. Careful management of the by-products is required to avoid recontamination of the source water.Regulators often drive mine owners toward reverse osmosis (RO) so that their discharges can be considered as æzero dischargeÆ in terms of potential pollutants. Such decisions need to be based on site-specific information rather than any form of æblanketÆ requirement. An analogy is that many humans like to consume mineral water rather than ænormalÆ tap water. Receiving environments also accommodate or even prefer their æmineralsÆ and so RO is neither warranted nor sustainable in many cases.This paper presents two case studies for operating mine sites, both of which have a significant excess of water requiring environmental discharge. The examples demonstrate a sensible balance between treatment type, environmental constraints, process implementation and residuals management. LIMN« æthe flow sheet processorÆ was used to model one of the case studies due to the complexity of the water system on that site.CITATION:Atkinson, B W and Thompson, P, 2013. Mine water - optimising for site and environment, in Proceedings Water in Mining 2013 , pp 9-14 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

By G F. Johansen

The erratic and localised occurrence of economic gold grades is a common feature of high-nugget effect gold veins. The nugget effect is a consequence of small-scale geologically controlled enrichment, and the inclusion or exclusion of sparse gold particles because of the sampling process. Such deposits do not always contain visible or coarse gold, and can be characterised by fine gold particles. Economic grade accumulations are generally contained within discrete oreshoots, which are surrounded by barren to low-grade material. Problems are often encountered where small sample types (eg drill core or channel samples) often vastly understate in situ grade, due to their general inability to intersect rare gold particles. As a result, the definition of grade and its distribution is often challenging, and leads to substantial resource uncertainty. Proxies, or indicators for grade, can help the geologist gain a better understanding of grade distribution and grade potential. These are based upon geological (eg mineralogical, textural, etc) and/or geochemical (eg specific elemental ratios, fluid inclusion compositions, elemental correlations, etc) criteria. The paper discusses the use and application of such proxies through three case studies.

Jan 1, 2004

By E M. Jones

On 26 June 2000 a hydraulic fill retaining barricade failed at the Bronzewing mine in Western Australia. The barricade failure resulted in the release of 19 000 m3 of saturated hydraulic fill into the mine, which caused the deaths of three miners. Following this tragic accident, the practices and procedures of mines using hydraulic fills came under intense scrutiny by regulatory bodies and mining companies. At this time, the use of hydraulic fill at NormandyÆs zinc/copper Scuddles mine was suspended and waste rock became the sole backfill material in use underground. By 2003, development of the mine adjacent to Scuddles, Gossan Hill had progressed to a point where a self-supporting fill material was required to enable full recovery of high-grade ore. Cemented hydraulic fill (CHF) was identified as the optimal fill type and work began on designing appropriate management procedures and controls to ensure the safe implementation. This work included definition of the fill properties, plant design and construction, reticulation system design, design of stope barricades and drainage systems and fill placement control and monitoring practices. CHF placement began on 16 July 2004 and has continued to date. Significant operational experience has since been gained in areas including plant performance, fill product quality assurance, barricade construction, stope drainage and in situ performance.

Jan 1, 2008

By A L. de Ambrosis, F M. Weir, M Fowler

Traditional kinematic and statistical analyses of geological structure for geotechnical engineering applications, while considered industry standard practice, have some limitations and unrealistic assumptions. An improved approach involves a discrete fracture network (DFN), a numerical model that explicitly represents how defects may be spatially distributed through the rock mass. The DFN technique utilises the structural data in stochastic analyses to give a range of possible models used for visualisation and stability analyses.The early development of the DFN approach was largely associated with modelling fractured hydrocarbon reservoirs and nuclear waste isolation programs. With recent improvements to computational power it has become recognised internationally as a valuable tool for modelling some geomechanical problems encountered when designing excavations in fractured rock masses. For tunnelling or slope stability projects DFN modelling provides visualisation of a rock mass and identification of likely failure mechanisms.This paper presents a suite of DFN modelling undertaken for the design of a tunnel within the Ashfield Shale unit of the Sydney Basin, Australia. The necessary input parameters and derivation of these, along with the importance of both an accurate engineering geology model and validation of the synthetic fracture network are demonstrated. Multiple realisations of the DFN were analysed to provide an indication of the number and volume of unstable blocks for the proposed tunnel geometry, enhancing support design. One fracture network realisation was sliced along multiple sections for use in finite element modelling.CITATION:Weir, F M, de Ambrosis, A L and Fowler, M, 2014. Discrete fracture network modelling for tunnel design in the Sydney Basin, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 219–226 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

Downhole survey uncertainties observed at various De Beers operations prompted an investigation into their possible effect on deposit shape and volume. An accurately surveyed artificial æboreholeÆ was constructed and different downhole survey instruments tested. In this way an empirically determined error range of 0.1 per cent to ten per cent was derived for downhole survey data. These survey errors were applied to an orebody model at an existing mine. Visualising the sphere of uncertainty associated with a borehole trace using a general mining package (GMP) gives an indication of possible volume variance. The resulting orebody maximum and minimum volume scenarios for three different depths (200 m, 500 m and 800 m) are presented. For certain instruments and borehole angles, the 3D positional error can be as high as 100 m at 1000 m down the hole. At depths below 200 m the resulting volume deviations can become significant for borehole survey errors exceeding 0.35 per cent. At 800 m depth the volume difference can approach 25 per cent. These figures assume that the error is compounded. The impact of these downhole survey errors is greatest for pipe-like orebodies such as porphyries and kimberlite pipes. Subhorizontal sill-like orebodies (and coal seams) will not be significantly affected by these errors. The impact of this type of survey error needs to be stated (and quantified) and is significant in JORC classification.

Jan 1, 2009

By J Cronin

For the last decade, we have read about the great technical innovation that is coming to the mining industry that will increase safety and productivity. There is consensus that it will be a technical innovation that will produce a step change in mining costs and outputs (as opposed to bigger machines or less people); however, this innovation (while freely available) has not taken hold in the industry. While there are a few mines that have embraced technology, the majority of underground mines simply do not have the expertise or technical capability to implement innovation and automation.With unexploited mineral deposits becoming deeper and more remote, and thus more hazardous to mine, telepresence offers the ability to remotely execute production tasks while separating personnel from hazards. As the technologies required to deliver telepresence mature, the potential for there to be no personnel underground during production activities is becoming a reality (the ‘dark factory’). So significant is the capacity of telepresence to mitigate risk, it is proposed that it be included as a separate entry in the hierarchy of hazard mitigation controls.Technical innovation such as the optimised short-term interval control of the production process and the automation of underground mobile fleets offer significant increases in production along with lower operating costs. This paper explores the most critical components for the successful implementation of technology in underground mining; redundant, robust and high-bandwidth communications networks to carry data from distributed networks of smart sensors and to convey teleoperation commands; and high-definition video to provide operators with detailed, real-time data. The days of analogue ‘leaky feeder’ as a base case for communications are over. The human resources required to support the expected wave of innovation are significant and will be difficult to maintain in remote areas as the same skills and expertise are in demand in other industries.The paper highlights barriers to innovation in the mining industry, and a lack of technical and scientific expertise within the industry to be able to identify, implement and manage technologies that can increase safety and productivity. As well, an over-reliance on basic net present value (NPV) financial analysis that is used in the industry punishes investment in technology (capital expenditure; CAPEX) and accepts higher operating expenditure (OPEX) due to the discounting of future savings in operating costs.CITATION:Cronin, J, 2017. Telepresence – the application of remote control and automation technologies for increased safety and productivity, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 213–224 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017

By M Nagarajan

Orica Mining Services (Orica) in partnership with Coal and Allied’s Hunter Valley Operations (HVO) has developed a risk management process to maximise mining efficiency whilst controlling vibration and maintaining critical electricity continuity to New South Wales (NSW) electricity grid in the Riverview Pit. The issue is a high tension tower which supplies electricity located within 40 m of mining and blasting activities. The process involved developing an understanding of the relationship between vibration, explosives, geology and the location of the blasting in the geological horizon. From this an optimum methodology for blasting in each region was developed.

Nov 8, 2011

By G Malherbe, J Gonzalez, D C. Franklin, J Bassan, C T. Farrelly

To respond to ever-increasing challenges, mining companies have been experimenting with new business models and technologies in order to speed mine development, production, processing and transport. The various experiments involve mobile access to data, intelligent sensors, advanced analytics, virtual collaboration, virtual reality, automated equipment, remote operations centres and strategic partnerships. A synthesis of all these components creates a ænetwork effectÆ that can dramatically improve the overall effectiveness the entire operation. The concept of the Network Centric Mine borrows from a variety of industries, including defence, aerospace, aviation, petroleum, utilities and manufacturing. Central to the concept are improvements to the way we connect people, process, information and technology, resulting in a more highly collaborative business model, with roles and processes designed to take advantage of new technology. The components of the mining operation act as a connected network aimed at a common goal, regardless of the boundaries of organisation and location.The design of this new organisational ecosystem needs to take into account the recent advances that enable the æplug and playÆ integrated collaborative environment, including cloud computing, mobile devices and social networking, as well as advances in augmented reality, robotics, geo-location, digital labelling, simulation and analytics. However, the most consistent lesson from other industries is the need to properly enable the behaviour and process changes necessary for success.Benefits from adopting a network centric approach include the more effective use of scarce expertise, improved data and information analysis, reduced process variance, and more informed and faster decision-making. The future of mining will see more technology savvy workers who will drive the adoption of new processes. The operations will shift from a relatively static and disparate set of functions, to a digitally aware, dynamic, automated, integrated and interactive environment, with increased agility, lower operating costs, higher productivity and improved safety.CITATION:Farrelly, C T, Malherbe, G, Gonzalez, J, Bassan, J and Franklin, D C, 2012. The network centric mine, in Proceedings International Mine Management 2012, pp 143-160 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 20, 2012

By M Wieloch, D Wimpenny, M Chappell

Fibre-reinforced geopolymer concrete (FRGC) contains no Portland cement or steel reinforcement, but instead uses synthetic fibre reinforcement and a geopolymer binder. The use of geopolymer binder in lieu of Portland cement reduces the concrete’s embedded energy (CO2 emissions) whilst the use of synthetic fibres eliminates the issue of reinforcement corrosion, thus enhancing the overall long-term durability of concrete. This paper presents the development of FRGC during a three-year project funded by the Victorian Science Agenda and a consortium of five organisations. The work involved laboratory and field trials and the production of prototype tunnel segments that have been subject to durability and fire testing.FRGC has exceeded the performance of the Portland cement-based control mix in terms of flexural strength, chloride diffusion, water sorptivity and drying shrinkage. Furthermore, the FRGC segments subjected to a simulated hydrocarbon fire test did not exhibit explosive spalling; however, the creep of FRGC was approximately three times that of the steel fibre-reinforced Portland cement-based control mix. The compressive strength and tensile splitting strength of the FRGC were also lower than the control mix. These differences need to be allowed for in the design using FRGC.Prototype bolted tunnel segments of up to 0.8?t mass have been produced from FRGC using standard production techniques and ambient curing. These were successfully produced within a 24-hour production cycle. Cut sections through the segments showed good compaction and even distribution of fibres. The estimated carbon footprint of tunnel segments produced using FRGC is approximately 70 per cent less than that of Portland cement-based segments containing 25 per cent fly ash and steel reinforcement.The results to date indicate that FRGC has the potential to produce a new generation of tunnel segments and, in general, precast concrete products with increased durability and substantially reduced carbon emissions compared to the Portland cement-based concrete with steel reinforcement.A summary of further research carried out by CH2M HILL into a complete elimination of ferrous inserts from segmental concrete tunnel lining is also summarised in this paper. The use of non-ferrous connectors for radial joints in combination with the FRGC technology in the manufacture of tunnel segments will effectively lead to development of a new generation of segmental tunnel lining systems.CITATION:Wimpenny, D, Chappell, M and Wieloch, M, 2014. Fibre-reinforced geopolymer concrete – an innovative material for tunnel segments, in Proceedings 15th Australasian Tunnelling Conference 2014, pp 345–352 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By J H. Zietsman

The transition to more sustainable metal production is receiving much attention at present, and the iron and steel industry is at the centre of the conversation. New, more environmentally friendly production technologies, such as direct reduced iron (DRI) smelting furnaces, need to be developed in a short period of time. This necessitates increased use of computational modelling that incorporates more accurate material descriptions. The combination of large-scale multiphysics models of high-temperature processes with CALPHAD material descriptions leads to infeasible computation times. This can be resolved with the previously reported RapidThermo framework, which has been demonstrated to make equilibrium calculations orders of magnitude faster, within controllable limits of accuracy. In this paper, we explain how further material properties, which are important to modelling hightemperature reactors, can be added to the RapidThermo framework. This can improve the accuracy and usefulness of process and multiphysics models in the development of new technologies, which can significantly accelerate development cycles.

Aug 21, 2024

By Bourne R. W, Smith T

This paper presents initial findings of a project examining novel processes for the treatment of refractory sulphidic gold concentrates. Non-oxidative roasting of such concentrates for 12 hours at 750¦C resulted in the finely disseminated gold agglomerating to form discrete grains. The pyrite and arsenopyrite decomposed to form pyrrhotite, whilst the labile sulphur and arsenic driven off was collected on a condenser as a mixture of elemental sulphur, metallic arsenic and various arseneous sulphide compounds. As a result, the cyanide solubility of the gold contained in sulphidic refractory gold concentrate from the Emperor mine in Fiji improved from 54.5 per cent to 98.4 per cent; from the Fimiston mine in WA (65.2 per cent to 96.6 per cent), from the Windarra mine in WA (69.6 per cent to 91.3 per cent), from the Harbor Lights mine in WA (20.4 per cent to 60.7 per cent), and from the Wiluna mine in WA (12.6 per cent to 28.0 per cent). The non-oxidative roasting conditions have not been optimised for each of these minerals. Subjecting the non-oxidatively roasted minerals to mild oxidative acidic iron sulphate pressure leaching (with typical temperature of 100¦C and typical oxygen overpressure of 500 kPa) to remove iron and so further liberate finely disseminated gold, resulted in the cyanide solubility of the gold exceeding 96 per cent for each of these five concentrate types (including those from Harbor Lights and Wiluna). Thiourea leaching of the sulphur-rich residues under acidic conditions resulted in remarkably high gold extractions being achieved. These novel processing options need to be optimised, and their economic viability established.

Jan 1, 1991

By W Malone, J Garrett

FLSmidth (FLS) has spent the last 15 years, working with customers and engineering houses to deliver innovative improvements in crusher safety, coupled with the latest, maintenance friendly, crusher design. The key focus being to prevent service personnel from working underneath the crusher during maintenance and obviate the need for personnel to be exposed to suspended loads when performing tasks such as, main shaft installation, for example. Improvements include: full top-service capability to ensure the safest and fastest way to disassemble the crusher for maintenance purposes, which also removes the requirement for a service cart; a selfaligning main shaft which ensures remote assembly is now possible, keeping service personnel well out of harm’s way; And rotable shells, or the ability to perform relines off-station, allows for quick shell ‘swap-over’ without the downtime associated with removing, refitting and curing time associated with epoxy backing. The high flow spider improves large material entry into the crusher, reducing blockages and downtime and therefore maintains crusher capacity. Each size of crusher in the range comes with an option to increase the standard feed opening to a larger one if desired to compensate for ‘blocky’ or ‘elongated’ feed material, a common problem for Pilbara hematite iron ores. Power capability has also been increased with a maximum of 1500 kW, to match the higher throughput capacities being achieved. This due to uprated eccentric speeds and larger discharge annulus. Increased eccentric throws and mantle diameters are also now a reality, when compared to more traditional designed gyratory crushers. To keep up with the improved design features of the Mk V, digitalisation has also been upgraded to maximise performance capabilities to ensure that the most efficient reduction and throughput capacities are achieved, whilst utilising the higher powers now available as standard. Condition monitoring ensures that the crusher is at its optimum operating capability by monitoring and adjusting the crusher settings via feedback from additional sensors, ie main shaft spin, temperature and vibration. Camera monitoring capabilities are available as is an advanced oil contamination monitoring system. As a result of the above design improvements, it will be shown that the Mk V range offers benefits such as: enhanced safety features, increased availability, faster maintenance turnarounds, higher power utilisation, equivalent product size at higher throughput capacities and with Remote operation capabilities. All of which result in a gyratory crusher with higher levels of safety and a lower per tonne operating cost.

Sep 18, 2023

By H Rossiter, C Simpson, J Market, P Jeanneau

Downhole Assay tools are a geophysical method to collect an instigated response from the material surrounding a drill hole and deliver a multielement proxy-assay. They were first tested in the Pilbara at the turn of this century, however since 2011 they have seen a more focused testing and implementation regime with multiple companies across multiple Pilbara mine sites. The increase in the volume of data has led to advances in the measurements and significant improvements to the efficiency of the calibration process. Pulsed Fast and Thermal Neutron Activation Analysis (PFTNA) downhole assay tools collect gamma photon spectra which are characteristic of elemental signatures. One of the key components of the technique is calibrating the spectral signatures to lab assays. Each tool is slightly different due to the organic nature of the crystal detector and therefore responds slightly differently. Environment and hole conditions as well as ore characteristics are among other external influencing factors. Thus, a unique calibration is required for each tool. In addition, not all elements are measured directly, but some are actually characterised by proxy, meaning that if the signal-to-noise ratio for an element is small, it may be easier to identify the mineral or geology in which that element is found and thus infer the concentration of the element. These proxies may differ for each site or geology type within a site. There is a large advantage to build a unique calibration per tool at each site rather than a universal one to be used across the whole province. This then delivers the accuracy and precision of measurements that mining companies require for modern operations. Early work with the tool required several thousand metres of calibration data and several weeks of analysis to build each calibration. This process has now been streamlined to significantly reduce the amount of data required and the analysis time to make it much easier to introduce new tools to a site with an existing model or to create new models. This paper details the calibration process, illustrating the increasing accuracy of the models as training data are acquired as well as the methods for transferring a calibration from one tool to another.

Nov 8, 2021