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By A Hughes, S G. Rosin

This paper presents the design and construction approach adopted for the widening and stabilisation of the existing decline tunnel forming part of the Scenic Railway Upgrade project at Katoomba in the Blue Mountains of New South Wales (NSW), Australia. The overall upgrade project included new trains and track, rebuilding of the top and bottom station and installation of a new winch and control system. All the works were undertaken over an eight-month period between August 2012 and April 2013 as part of a $30 M upgrade of the railway.The railway is the steepest cable-driven line in the world at a maximum of 52° extending over 350 m and descending from the escarpment into the Jamison Valley. The track was built in the 1880s for coal haulage and is recognised as a remarkable engineering achievement for its time. The tunnel section extends for about 120 m at the start of the decline and is about 3.5 m wide and 3.5 m high. The tunnel was excavated principally within medium to high strength Banks Wall sandstone and given that the widening only involved about 200 mm of trimming of the crown and sidewall this aspect of the work was not a critical support issue, except at the upslope portal. The tunnel crown however is entirely intersected by a major near vertical shear zone which presented significant challenges for the tunnel stabilisation works.Three-dimensional laser survey scanning was used for definition of the tunnel clearance envelope for the widening, and also to subdivide the tunnel into various geotechnical sections to assist in support design. Specifically oriented rock bolts extending beyond the shear zone into stable rock were used together with mesh, shotcrete and extensive strip drains and flushing points for drainage of the shear zone.Unique aspects of this project were included into the specifications and work methods. This included construction of a mobile working platform for tunnel works, the use of dry shotcrete application, difficult access for rock bolting and limiting vibration during the tunnel trimming works due to the risks associated with crown instability. The works also took into consideration particular safety constraints/work exclusion areas to address the risk of detachment of rock which could mobilise downslope to the track area below. This was required because other works were in progress such as micro-piling and bottom platform works which were being undertaken concurrently with the tunnel work.CITATION:Rosin, S G and Hughes, A, 2014. Scenic Railway Tunnel upgrade in the Blue Mountains, New South Wales – an approach to design and construction, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 607–618 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By L Drowley

The Adelaide Desalination Plant (ADP) draws raw sea water into the facility and returns saline concentrate to the Gulf St Vincent via subsea conduits. This paper describes the detailed design and construction methodologies developed for the cross connection tunnel excavation. The paper concentrates on key design elements which include:· lateral breakout support of the segmental tunnel lining,· ground improvement grouting in the zone of the cross connection tunnels due to extremely variable and weak ground conditions, and· excavation methodologies and proposed support types of the riser to tunnel cross connections.The design process consisted of developing concepts, detailed risk assessment, three-dimensional (3D) finite element modelling and structural analysis for temporary support of tunnel lining; functional design of the ground improvement grouting and the temporary support; and permanent lining design of tunnel to ocean riser connections in a mixed soft ground/hard rock environment.The paper also presents conclusions of the design based on construction data available, and highlights the close collaboration between the design team and construction team.

Mar 8, 2011

By M Campbell, A Jeffcoate, J-C Vannay, B Perriaux

Phyllite waste rock at the Simandou Pic de Fon and Oueleba Iron Ore deposits (Guinea, West Africa) variably weather to form clay-rich rocks. This weathering modifies the mineralogical, geochemical and mechanical properties of the phyllites. Final pit walls will largely be formed in phyllite, so it is critical that the slope design takes account of the distribution and variability of weathering within this material. Phyllite intact material strength has been correlated with geochemistry (ie mineralogy) facilitating the establishment of domains of intact rock strength (IRS). In order to calibrate this geochemically-based strength model, core from diamond drilling (DD), comprising a variety of phyllite material types (from soft clay to moderate strength rock), was geotechnically logged to assess intact strength; further validation was achieved by uniaxial compression (UCS) testing and point load tests (PLT). The correlation between geochemistry and strength offers a potentially powerful tool for differentiating basic mechanical properties of the rock mass, especially at Simandou where a significant proportion of the resource drilling is done by reverse circulation (RC). Unlike DD, reliable measurements of material strength from RC samples can prove difficult, especially in clay-rich material. Therefore, gaining information from routine geochemical assay results, independent of the sampleÆs physical integrity, is a valuable and cost-effective source of reliable empirical data. Data acquired using this approach provides an opportunity to develop strength domains, which are integrated into mine planning block models. In combination with other geotechnical characteristics, this can be a valuable input to the development of geotechnical models. This technique has allowed spatially representative rock strength data to be derived and offers the potential for optimising pit slope angles in areas where hitherto conservative design criteria had been assumed.CITATION:Jeffcoate, A, Campbell, M, Vannay, J-C and Perriaux, B, 2013. Modelling intact rock strength of clay-rich rocks with geochemistry at the Simandou iron ore deposit, Guinea, West Africa, in Proceedings Iron Ore 2013 , pp 193-202 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By N Herault

PT Freeport Indonesia recently completed preproduction development and construction of the Big Gossan underground copper and gold mine, located in the Ertsberg mining district of Papua, Indonesia. Production has commenced with an expected ramp-up to full production of 7000 tonnes per day in 2012. The Big Gossan utilises an open stoping mine method with paste backfill.In order to deliver ore to the mill, which sits in a valley above the ore deposit, an underground production shaft and hoisting facility was designed and constructed as the key component of ore haulage. The design and construction of the Big Gossan shaft posed many challenges to the project team. Available shaft design and construction expertise were limited as this was the first shaft of its kind in Indonesia and the project was undertaken during a time of high industry demand for new shaft systems. Construction resources were also limited due to the remote location and competition with existing, producing mines for these resources and skills. The project also taxed the ability of Freeport to provide services and resources to this as well as their other projects.Completion of the Big Gossan shaft was a milestone in PT Freeport Indonesia’s plan to fully transition ore production to the underground environment in this decade.This paper deals with the various challenges faced by PT Freeport Indonesia and shaft contractor, PT Redpath Indonesia, during the construction of the Big Gossan shaft and offers suggestions to improve future shaft projects of a similar nature.

Mar 21, 2011

By M Jara, R Nuñez

As the global interest in sustainable energy sources has increased, lithium has emerged as a vital resource, playing a crucial role in the transition towards a cleaner and more efficient economy, but with this comes important challenges, especially associated to health, safety, and environmental matters. So, it is imperative for the lithium industry to prioritise HSE measures to protect workers, environment and surrounding communities. Implementing robust safety protocols and technology helps ensure the sustainability of mining operations and contributes to the overall responsible development of the industry. In this work we present how the Chilean lithium mining industry becomes a safer and more compliant industry using digital transformation (Cochilco, 2018; Bradley et al, 2013; Cabello, 2022).

Apr 16, 2024

By J W. Glatthaar, M Mavotoi

The occurrence of fluorine in the copper/gold concentrates produced by Ok Tedi Mining Limited has provided a series of challenges to metallurgists since 1988. Although fluorine is distributed throughout the gangue minerals contained within Ok Tedi ores, itsÆ presence in talc and phlogopite (naturally floating fluorosilicates) has proven to be the predominate sources of fluorine in the final concentrate. Initial treatment for the fluorosilicates consisted of the use of a carboxy-methyl cellulose depressant added to the flotation cleaners. This was superceded in 1998 with the installation of a fluorine reverse flotation process for the removal of naturally floating fluorosilicates from the final concentrate when the fluorine content of the final concentrate exceeds smelter-defined trigger points. The fluorine reverse process is similar to by-product molybdenite concentrate production in that sodium hydrosulfide is used to depress copper/gold flotation whilst allowing the fluorosilicates to float. The process was installed in two parallel modules (to match the existing grinding/flotation modules at Ok Tedi), each consisting of a closed rougher/cleaner circuit configuration. Both rougher and cleaner cells are Jameson Cells from MIM Process Technologies, with the selection based on both processing characteristics and available construction space. This paper discusses both the nature of fluorine in-, and its removal from-, Ok Tedi copper/gold concentrates.

Jan 1, 2003

By C De-Vitry

In skewed distributions seen in many geochemical data sets, samples at the extreme ends of the distribution are often termed ‘outliers’. Samples considered as outliers can often make exploratory data analysis and resource estimation more difficult and less reliable. Such outlier samples may be legitimate because they are part of a natural high- or low-grade tail in the distribution. How these samples are identified and dealt with in resource estimation can often be a material issue for the Competent Person, particularly under the latest edition of the JORC Code (JORC, 2012). This paper discusses the identification and characterisation of outliers and high- and low-grade tails and proposes methods to deal with them in estimation.For dealing with outliers and high-grade tails ,very simple approaches, such as top-cutting through to more advanced geostatistical approaches, are discussed. The strengths and weaknesses of each approach are also outlined. Some examples of how the underlying geological understanding of a deposit influences the view of outliers and low-/high-grade tails is provided. The importance of documenting, communicating and challenging a given geological model is also discussed. Finally, some ideas for dealing with the uncertainty created by outliers are outlined.CITATION:De-Vitry, C, 2014. Identifying and dealing with outliers in resource estimation, in Proceedings Ninth International Mining Geology Conference 2014 , pp 159–168 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By A M. Suchowerska, J P. Carter, J P. Hambleton

"In order to effectively predict the roof collapse of underground openings using continuum models, it is imperative that a realistic failure criterion is used to represent the rock mass. However, for coal mining operations, there is still uncertainty as to the appropriate failure criterion that should be used for the coal measure strata. This study compares stability numbers and collapse mechanisms for a rectangular underground opening predicted based on three commonly used failure criteria: the standard Mohr-Coulomb, Mohr-Coulomb with a tension cut-off and Hoek-Brown. Three methods of analysis are considered: an analytical upper bound method an upper and lower bound finite element formulation the displacement finite element method.The theoretical results are also compared with field measurements of subsidence above longwall coal mining. For the standard Mohr-Coulomb failure criterion, the friction angle governs the shape of the collapse mechanism, and the so-called critical width (the cavity width above which failures extend to the ground surface) ascertained from field observations in the New South Wales coalfields corresponds to a friction angle of approximately 30°. On the other hand, predictions obtained based on the Hoek-Brown failure criterion consistently overestimate the critical width. The results also show that tensile failure governs the stability of the cavity and shape of the collapse mechanism when a tension cut-off is introduced for the Mohr-Coulomb yield criterion.CITATION:Suchowerska, A M, Hambleton, J P and Carter, J P, 2014. Prediction of roof collapse for rectangular underground openings, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference, pp 367–374 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 5, 2014

By J Darbritz

"This paper details the events leading up to a slope failure that occurred at Kalgoorlie Consolidated Gold Mines (KCGM) and the remediation method executed using rope access specialists.n January 2016, KCGM Fimiston Pit experienced a double bench wall failure where approximately 80 000 t of material fell from the wall that blocked access to a ramp and caused minor damage to equipment.The event was triggered by heavy rainfall and occurred along unfavourable eastward dipping structures that lead into weaker shale/porphyry bands, which in turn left more material on the face. A remediation plan was formulated that would allow for the continuation of open pit operations while a full geotechnical assessment of the failure area could be conducted. This was accomplished by means of rope access specialists who abseiled down the wall and blasted off the remaining overhang using a portable drill rig and prepackaged explosives.This paper provides a brief overview of the KCGM operations, how the instability was identified and monitored, details of the failure event, outcomes of the geotechnical assessment and details on the remediation work.Citation:Graf, C and Sullivan, R, 2016. The Journey to Steepening the Pit Slope Angle - Advancing the Effectiveness of Wall Control, in Proceedings Ninth AusIMM Open Pit Operators' Conference 2016, pp 104–114 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 15, 2016

Avoca Resources LimitedÆs Higginsville Gold Project has a resource base of over 1 300 000 oz of gold. The Trident underground mine, which forms the basis of the project development, has a resource base of 927 000 oz of gold. Avoca is building the Higginsville Gold Project based on a minimum ten year vision, producing over 150 000 oz per annum. The project development has taken less than three years from the Trident discovery hole in October 2004 to the first ore production in June 2007. This paper discusses the background work associated with the development of the Trident underground mine in a difficult period for new project development in Western Australia. The resources boom, led by the iron ore industry in the Western Australian Pilbara region, is creating cost pressures and, combined with a lack of people and equipment, is placing cost and timing stress on a small developing project. Avoca Resources has developed a project execution management strategy aimed at mitigating cost blow outs and schedule delays.

Jan 1, 2008

By S Wellink, D Chalmers, D Adermann, C Martin

The practice of recording blasts for quality control purposes has been conducted for several decades. However, at the low frame rates of a standard video camera, essential data is frequently missed as it occurs when the shutter is closed between frames.The use of high-speed video for the research, development and monitoring of the performance of blasting procedures is a well proven but under-utilised practice.The recent development of low cost, easy to use high-speed digital cameras and user friendly software can deliver a capability into mine management as a day-to-day production tool that can greatly improve blasting performance and reduce costs.Digital high-speed video and image analysis software can accurately quantify each blast. Analysis of the images can facilitate the identification of causes of variance from design, geology changes, errors in blast practice and areas of poor performance. The use of high-speed video greatly enhances the audit and review processes so that future blast design can be quickly and appropriately modified to deliver improved blasting performance and reduced costs.The three videos demonstrate the differences between standard video and high-speed video and the detail that can be obtained from them. These videos of open cut blasts can be used to identify blast performance variances. Capturing images at 1000 frames per second allows the analysis on a millisecond timescale where detonator timings, fragmentation, venting, fume generation and flyrock can be accurately identified.CITATION:Adermann, D, Chalmers, D, Martin, C and Wellink, S, 2015. High-speed video – an essential blasting tool, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 471–476 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

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

Jan 1, 2003

By J Shandro

This paper stems from recent multidisciplinary research between mining engineering and health researchers at the University of British Columbia and the University of Victoria, Canada. It considers the implications of a future state of sustainable mining development that places more emphasis on consideration of mine community health and sustainability within the definition of mine planning best practice. It reviews recently completed research studies on mining and other resource communities in British Columbia, Canada and a process undertaken by the research team to share research findings. It then examines the outcomes of this knowledge sharing process placing emphasis on the development of a more collaborative and enhanced mine planning process that integrates community- level indicators of health and sustainability to more effectively address mine impact-benefits. The paper concludes by discussing current initiatives that aim to benefit the mining industry, communities, and governments as they plan future mineral development projects.

Nov 22, 2011

By B Taylor

The Perseverance deposit is the most southerly known economic copper/gold deposit within the Cobar gold field. The deposit is situated approximately 12 km to the south-southeast of Cobar and is essentially blind to surface with the top of economic mineralisation occurring 750 m below ground level.Based on the December 2010 resource estimate (inclusive of reserves and net of depletion) the deposit contains 3 011 000 tonnes at 6.1 g/t Au and 0.90 per cent Cu (590 000 oz of gold and 28 000 tonnes of copper). The deposit is comprised of four principal lenses, the Perseverance, Hulk, Zone B, and Hercules lenses. In excess of 90 per cent of the known resource tonnes are contained within the Perseverance and Hulk lenses. The deposit is shear related and hosted within lower Devonian rocks of the Cobar Basin. The competency contrast of rhyolites juxtaposed against sediments by the Peak-Perseverance shear is the principal control on mineralisation. Both the Perseverance and Hulk lenses are primarily hosted by brecciated rhyolites juxtaposed against Chesney formation sediments across the Peak-Perseverance shear. This faulted rhyolite sediment contact roughly defines the global orientation of the deposit. The Perseverance lens continues within the shear for up to several hundred metres beyond the extent of the faulted rhyolite sediment contact. Mineralisation within the shear beyond the faulted rhyolite contact zone is hosted by sheared silicified sediments. The Perseverance lens remains open at depth and to the south.The Zone B and Hercules lenses, which are significantly less important in tonnage terms, are hosted by rhyolite breccias within the main body of the rhyolite and appear to be only tenuously related to the Peak-Perseverance shear. Within the Perseverance lens, the presence of northeast trending high grade breccia veins developed oblique to the north-south trending shear system has led to the development of steeply north plunging high grade ore shoots within a globally north-south trending mineralised domain. These high grade shoots have limited horizontal continuity but significant down plunge extent.The presence of coarse gold and the resulting strongly skewed nature of the gold grades, in conjunction with controls on mineralisation which are not parallel to the mineralised domain, has led to predictive difficulties regarding stope performance.Strong heterogeneity of the gold content of the ore and geological controls on mineralisation which are not parallel to the global trend of the mineralisation impose a set of difficulties which sound geological control is helping overcome.

Aug 22, 2011

By P G. Greenhill

The Wonawinta silver project near Cobar in NSW is under development by Cobar Consolidated Resources Limited (CCR). RMDSTEM Limited is part of the owner’s team for feasibility, design, engineering, construction and commissioning.With a 51Moz resource CCR is one of the largest pure silver players in Australia. A probable reserve of 14.3Moz has been defined for a mine life of approximately five years. The silver mineralization is contained in host rock composed of clays and oxidized limestone. The ore also contains on average 1.3% lead as cerussite, and other minerals. A simple circuit consisting of slurrying of the ore, gravity treatment of the coarse fraction to recover lead, silver extraction using CIL, elution and the Merrill Crowe silver recovery process, has been developed.The “value engineering” approach to this development pioneered over the past decade by RMDSTEM has meant that RMDSTEM has delivered the bankable feasibility study at a cost of $0.07 per resource ounce. It is highly cost effective making efficient use of shareholders funds as well as being very time efficient. This paper describes the application of the value engineering approach to the development of the Wonawinta project.

Aug 8, 2011

By R W. Shaw

The MTM Process targets treating lower grade and/or problem concentrates that are not attractive to smelters. The process has been developed at laboratory scale for copper and is based on a related development for zinc that has been extensively developed both in the laboratory and through pilot testing. The basis of the process is novel ammonia-ammonium chloride leach chemistry adapted to give high copper extraction whilst being selective over iron, arsenic and many other elements. The preferred flow sheet depends on location, especially infrastructure and utilities. These impact upon the leach and crystallisation stages more than copper reduction.

Aug 24, 2022

By A J. Morrison, K Demir, J Kohmuench, K Runge, C Evans

The Eriez HydroFloat® is a flotation device capable of recovering significantly coarser and lessliberated particles than is possible using a conventional mechanical flotation cell. Originally developed for industrial and bulk mineral beneficiation, the HydroFloat® is attracting increasing interest as a means of increasing the required grind size for metalliferous ore flotation. Doing so would reduce the costs of processing complex ores, either by decreasing the energy required to grind the flotation feed or by increasing the throughput achievable with a given comminution circuit. Processing coarser particles would also result in coarser waste streams, potentially improving the mechanical and hydraulic performance of the waste dams that they are sent to. Recent work at pilot – and industrial-scale has proven the potential of the HydroFloat® technology to achieve these gains in metalliferous applications. However, in order to realise the full potential of the HydroFloat® technology, it is necessary to understand not just its performance but also the drivers for that performance. Doing so will allow the design and operation of HydroFloat® devices to be optimised for different ores and applications. For this work, a HydroFloat® pilot rig was deployed to a coppergold plant in Australia and was used to investigate the effect of stream and operating conditions for treating the tailings stream of one of the plant’s rougher flotation cells. Under each set of operating conditions, samples were taken of the HydroFloat® feed, tailings and concentrate streams, and processed to yield the grade and recovery achieved by the device. At the same time, the bubble size and bed behaviour inside the device were measured. This paper presents preliminary relationships observed between the operating conditions and the performance of the HydroFloat® cell, and thus suggests a range of possible drivers for the measured coarse particle flotation performance.

Aug 24, 2022

By Q Qu

Reliable prediction of longwall gas emission sources and rate plays a critical role in mine ventilation and methane drainage capacity planning. Over the years, Australian longwall mines have been using the historic Winter method and the Flugge method in modelling specific gas emissions (SGE). The predicted results often experience high discrepancies from the operational reality. To improve gas emission prediction, post-mining gas contents were measured in several mines in Qld and NSW by safely drilling core holes into the longwall goaf. The results revealed many new insights into gas emission characteristics from different coal seams and the drawbacks of the European methods in their use in high-production gassy Australian longwall mines. Based on measurement data, a new, time-dependent gas emission prediction model has been developed. Considering several factors such as caving, desorption and production rate, the new model can predict more accurate and meaningful gas emissions to meet today’s needs in mine gas emission management. A case study is provided to demonstrate the application of the new SGE model.

Oct 12, 2022

By T Hicks

Designers of mining facilities play a significant role in defining the overall mine greenhouse gas emissions performance. This demands an appreciation of all the greenhouse gas emissions sources, including Scope 3 emissions, which will form an increasing fraction of the emissions as we transition our generation sources to renewable energy. Traditionally overland conveyors are designed to operate as fast as practical, and through this approach, achieve relative minimisation of: conveyor belt tensions; belt width; mechanical equipment masses; structural steel quantities; and concrete quantities. It is well understood that higher belt speeds reduce capital cost and improve project economics. Operating at higher speeds introduces operating costs through system energy losses and increased wear rates. This paper assesses the life cycle greenhouse gas emissions for a typical iron ore overland conveyor to demonstrate how the design criteria and engineering decisions impact greenhouse gas emissions and project economics. An analysis of the decarbonisation potential and project economics using a range of operational parameters has been completed, developing a marginal abatement cost for each system configuration, creating a basis for integration of low emission overland conveyor designs as part of the broader facility decarbonisation strategy.

Sep 1, 2024

An Integrated Geology-Mine-Plant and Eco-Efficiency Simulator for Anglo Platinum's Evaluation and Operational Improvement Initiatives

Sep 13, 2010