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By R McIlwraith, B Breul

Two case studies are presented in this paper. The first one discusses a roller compacted concrete water supply dam that was constructed in El Mauro in Chile to provide water for agriculture activities downstream of a copper mine during the dry season. The 23 m high dam used a bituminous geomembrane (BGM) as the low permeability upstream facing element on the dam to control seepage through the dam. This is the first time that a BGM has been used in this application. A deep cut-off trench was used to control seepage beneath the dam and through the abutments. This paper briefly presents the design of the dam, including selection of the concrete mix and maximum aggregate size that the use of the Coletanche BGM allowed, and provides details of the construction, quality control and assurance of the installation of the BGM. An ultrasonic apparatus was used as part of the quality control on the BGM seams.The second case study discusses a tailings dam in Cerro Lindo, Peru (near Chincha), where a watertight BGM was installed on the upstream face. Results are presented of the survey done by a consultant on the behaviour of the dam and in particular of the BGM following an earthquake of magnitude 8.1 in Chincha close to the site. These findings on-site were checked by trials in a laboratory in California. Test results are given and explained.CITATION:Breul, B and McIlwraith, R, 2015. Case histories – roller compacted concrete dam waterproofing with a bituminous geomembrane in Chile and a tailings dam in Peru subject to an earthquake of 8.1 magnitude, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 367–372 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

By Y Lanwin

The Australian mining industry, a cornerstone of the nation’s economy, is on a journey towards greater equity and inclusion. Th paper introduces a comprehensive exploration of how universal design principles, stemming from architectural roots, have evolved through automation and digital technology into the more encompassing frameworks of inclusive design and equitable design. The paper proposes a practical framework for those involved in work, facilities and equipment design in the mining industry to identify and assess for equity and inclusion. Universal Design emerged in the 1960s with a primary focus on architecture, aiming to create spaces accessible to people of all abilities. Its foundational principles sought to ensure equitable use, flexibility, simplicity, perceptibility, tolerance for error, low physical effort and optimal spatial considerations. Over time, these principles evolved and expanded beyond physical spaces, finding applications in various fields, including technology, education and transportation. In response to advancements in technology and a growing understanding of the multifaceted nature of diversity, Universal Design evolved into Inclusive Design. Inclusive Design goes further than mere accessibility, considering a broader spectrum of users with varying cognitive, sensory, cultural and socio-economic backgrounds. It emphasises user centred design, customisation options, diverse user research and continuous iteration. Equitable Design emerged as a framework that addresses not only the diversity of needs but also systemic disparities. It emphasises fairness, justice and the elimination of structural inequities. Equitable Design encompasses accessibility and affordability, representation and diversity, ethical considerations and community engagement. This paper will explore the applications of these design principles through a series of case studies including village and on-site facilities, remote operations and office based work design and technology design. By applying these frameworks in a mining context, the paper proposes that mining companies and suppliers can improve diversity, equity and inclusion leading to safer, more engaged and productive workplaces.

Apr 16, 2024

By M H. Randell, J B. Haines

The Honeymoon Uranium Project comprises the Honeymoon Deposit,Goulds Dam Deposit and Yarramba Prospect in the Southern Lake Fromeregion, South Australia. Both the Yarramba Prospect and HoneymoonDeposit (which includes Honeymoon and East Kalkaroo orebodies) arelocated in the Yarramba Palaeovalley. The Goulds Dam Deposit is about75 km north west of Honeymoon, in the Billeroo Palaeovalley. Exploration for sediment-hosted uranium began in the area in the late1960s, culminating in the discovery of Honeymoon and Goulds Dam inthe early 1970s. In 1982, a 25 L/s demonstration plant was built atHoneymoon to confirm suitability for in situ leaching. The project was put on hold in 1983 due to changes in government policy. Southern Cross Resources Australia Pty Ltd acquired the project in mid 1997. Roll-front deposits form from a migrating geochemical cell, anadvancing reduction-oxidation interface between oxygenateduranium-bearing groundwater and its reduced aquifer host. The source of metal is uranium-anomalous granites, which were eroded fromsurrounding ranges. The weathered granites and resultant sediments are stripped of uranium by oxidised groundwaters, to form solutions carrying uranyl carbonate complexes. The solutions percolate down-slope through permeable sand zones until contacting a reduced environment where uranium precipitates. Uranium mineralisation occurs interstitially between and as thin coatings on sand grains, usually in the form of uraninite or coffinite. The palaeovalleys (previously termed palaeochannels) are incised intounderlying Cambrian/Precambrian basement rocks and filled withsemi-consolidated, largely un-cemented, Tertiary sediments of the Eyre Formation. The late Palaeocene to middle Eocene Eyre Formation is the basal unit of the Tertiary succession in the Callabonna Sub-basin of the Lake Eyre Basin. Further to the north, the Lake Eyre Basin overlies the Jurassic-Cretaceous Eromanga Basin, which comprises much of the Great Australian Basin. Eyre Formation sediments are in turn overlain by the late Tertiary Namba Formation and terrestrial Quaternary units. At Honeymoon, the Eyre Formation includes immature, pyritic,carbonaceous sands and gravels interbedded with lignite andkaolinite-illite-montmorillonite clays. It was deposited by braidedstreams during epeirogenic uplift of the Olary Ranges, accompanied bysubsidence of the Lake Eyre Basin. The Eyre Formation comprises aconsistent stratigraphy of interbedded sand and clay units that arecontinuous over the Honeymoon Deposit but with local variationindicating some hydrological connection between aquifers.In the Honeymoon orebody, uranium occurs within coarse-grained,pyritic sands where the basal sand pinches out between overlyingcarbonaceous clay and the southern palaeovalley slope. Its characteristics are typical of the well-developed, planar limb of a roll-front uranium deposit. Zonal changes related to the reduction-oxidation interfaces across the deposit are readily observable. The orebody extends for nearly 1000 m along the valley margin, is 400 m wide at its maximum and averages about 6 m in thickness. The East Kalkaroo orebody also lies near the southern margin of theYarramba Palaeovalley. It extends discontinuously for approximately 3.5 km and averages 200 m width, with significant uranium present in the Middle as well as the Basal Member. The Billeroo Palaeovalley extends northward for 40 km sub-parallel tothe western side of the Benagerie Ridge, is up to 5 km wide and hasgently dipping banks. Eyre Formation within the palaeovalley isconcealed beneath 90 m of Quaternary and Namba cover, isapproximately 40 m thick, and is sub-divided into three upward-finingunits, which are remarkably similar to the Yarramba Palaeovalleysequence.

Jan 1, 2001

By A S. Derrington

This paper describes a hybrid ventilation system, which uses secondary fans that also act as de-facto primary fans to extract fresh airflow from the mine intake raise system. Also discussed are the associated problems such as uncontrolled recirculation, inadequate decline airflow, fire safety issues, prolonged blast fume clearance times, high air temperatures in main access routes, neutralisation of mine air cooling by heat from secondary distribution fans, increased ventilation system complexity, reduced flexibility and high pressure differentials (which cause safety issues with personnel access and reduce secondary ventilation system performance).Practical suggestions are provided on options to avoid these problems listed.CITATION:Derrington, A S, 2013. A critique of the push-pull hybrid ventilation system, in Proceedings The Australian Mine Ventilation Conference , pp 73-78 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By S Hall

Mining schools around the world, many unfortunately now closed, were often established to teach the techniques of narrow vein mining and associated processing to students studying part-time while working in the industry. This arrangement ensured graduates (or æassociatesÆ) had a mix of skills and knowledge invaluable to the industry.It is argued that there is still a need to educate students in these narrow vein techniques and that there will be a growing demand for such graduates with a high level appreciation of this type of mining. There is also a need for innovation in narrow vein mining and processing to develop specific technologies and allow the use of techniques applied in æbulk miningÆ to achieve improvements in productivity, safety and economic performance.This paper aims to review the situation with regard to education and innovation in narrow vein mining.CITATION:Hall, S, 2012. Narrow vein education - back to the future?, in Proceedings Narrow Vein Mining 2012 , pp 23-26 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 26, 2012

By R Strand, B Usher

Environmental compliance and mine designs are increasingly including assessment of flows and water qualities as a key driver to decision-making over life-of-mine. Integrated site-wide water quality models linked to dynamic water balances have been used for regulatory submissions, feasibility studies, operating mines and mine closure studies. These models, developed in GoldSim, link aqueous chemistry to the physical system of the site-wide water balance. Geochemical mechanisms included are determined from geochemical characterisation and site water monitoring, depending on the data availability at each site. External geochemical modelling using PHREEQC, version 2 (by D?L?Parkhurst and C?A?J?Appelo) and Geochemists Workbench (GWB), (by C?M?Bethke and The Board of Trustees of the University of Illinois) identifies the most important geochemical processes to be included in the model as a series of geochemical mechanisms which include source term loading rates, pH-buffering and equilibration of water quality. Water balance components include seasonal flow variability; waste facility water storage and system lags; run-off variability; milling processes and tailings production as a function of ore types; simulation of automated and scheduled maintenance of settling ponds; water re-routing for water treatment and freshwater demand, usage and storage.Case studies illustrating the use of these models for regulatory submissions and mine feasibility studies in a variety of climatic and regulatory environments show the utility and applicability of these models. Site-specific examples of these models developed by Klohn Crippen Berger Ltd are currently used at operating mines across the world. One of the larger mines where this is used is a mature poly-metallic mine in South America where the model has aided mine managers in understanding how various planned initiatives and potential water options will result in changes to flows and water quality. It is used regularly to inform water and waste management to minimise impacts to the receiving environment as a consideration of both flows and concentrations. The mine has also used the model in support of water treatment design, regulatory submissions and mine closure planning.Further examples of feasibility and operational/compliance assessment in arid and strongly seasonal environments for planning, regulatory and closure consideration of mine wastes and pits have shown the utility and usefulness of these approaches for a range of mining operations at various stages of mine life.CITATION:Strand, R and Usher, B, ?2014. Integrated site water balances and water quality models for decision-making over life-of-mine, in Proceedings Life-of-Mine 2014 , pp 271–284 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By P K. Singh

Recent advancements in understanding the detonation process are noteworthy, but they are still based on somewhat hypothetical situations. The actual variables that are essential parts of normal blasting practice have not yet been taken into account in such treatments. These include the various initiation practices employed to detonate a column of explosive, from single point initiation to multi-point initiation in blast holes, and the effect on detonation characteristics of both detonators and explosives under multi-deck and multi-hole blasting conditions. The in-the-hole velocity of detonation (VOD) of an industrial explosive is dependent on explosive’s charge diameter and blasthole diameter. The relationship between blasthole diameter and VOD provides a fundamental guideline to the rate of energy conversion and energy release within the detonation front on the interaction of explosives with the confining medium.The in-the-hole VOD of explosives was measured at four experimental sites in India for different blasthole diameters, ie 150 mm to 311 mm, but for identical explosive composition being same particle size, density, viscosity and loaded into blastholes with the same degree of confinement. The results of the studies demonstrated that there is definite relationship in in-the-hole VOD of the explosive and the diameter of the blast hole. The study also confirmed that the explosives initiated with concentrated boosters yielded higher VOD in comparison to those explosives that were initiated with multi-point priming. The measured increase in VOD of explosives for increasing diameter of holes was up to 24 per cent. The rate of change in in-the-hole VOD of explosives increases with increasing blasthole diameter. It can be further stated that the in-the-hole VOD of the explosive reaches a fairly constant value after reaching a limiting/threshold diameter of 311 mm.

Nov 8, 2011

By B W. Atkinson

Full-stream mechanised sampling apparatus, that collect a full cross-sectional increment from the complete screen discharge, will always be the preferred option for sampling screen overflows. However, the reality is that provisions for automated sampling are rarely, if ever, provided at the discharges of individual screens within beneficiation plants.Sampling from the discharge of high capacity vibrating screens, especially multi-slope screens, is subject to sampling bias, due to the stratification of the ore that occurs on the vibrating screen deck. The stratification in the vibrating bed translates to a stratified falling stream at the discharge end of the screen, typically with smaller particles at the back of the falling stream and large particles at the front of the falling stream (Figure 1).The chemical and physical characteristics of heterogeneous ore (mineral or coal) particles vary significantly with particle size. If samples do not correctly reflect the source material size distribution, they will be biased and the resulting analytical/assay data will not reflect the actual physical nor chemical characteristics of the source material.Prior published data for coal preparation research (Australian Coal Association Research Program) has demonstrated that a bias appears to exist for samples collected from high capacity multi-slope screens.A new form of sampling scoop has been developed with the aim of overcoming this issue.Bias was evaluated at a coal preparation plant by comparing the desliming screen overflow size distribution to that for æreferenceÆ coal preparation plant feed samples collected using the recognised stopped-belt technique. The study procured 20 sets of comparison samples in order to ensure statistical relevance.Two forms of sampling device were employed for the multislope screen discharge.A conventional square aperture scoop was demonstrated to exhibit a significant coarse bias, in that the resulting samples exhibited a significantly coarser size distribution compared to the reference samples. In other words it was evident that the conventional scoop æfavouredÆ material from the front of the falling stream.A new æcollapsibleÆ sample scoop was evaluated in parallel, and its samples were found to exhibit no relevant bias.CITATION:Atkinson, B W and Swanson, A R, 2012. A new method for sampling from high capacity screens, in Proceedings Sampling 2012 , pp 89-94 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 21, 2012

By Fulton B, Stewart R, Leach T

Gold mineralisation at Porgera is inferred to have been derived from a deep differentiated magmatic source which is capped by a series of (now tilted) inward dipping sills and stocks, which comprise the Porgera Intrusive Complex. An arc normal transfer structure provides a conduit, at the intersection with an arc parallel structure, into which basic magma derived from the deep melting of mantle material has been emplaced. Two phases of mineralisation display an association with late stage feldspar porphyry intrusives. Stage I carbonate-base metal-style gold mineralisation occurs as early quartz-sericite, then massive sulphide and late zoned Mn-Fe-Mg-Ca carbonate vein/breccias. Magmatic fluids derived from the deep magma source, are interpreted to have migrated along the margin of a feeder stock to the sills, and south to Waruwari. Stage II epithermal Au-Ag quartz-style gold mineralisation occurs as early fluidised breccias and carbonate veining, followed by zoned quartz-roscoelite-carbonate-gold vein/breccias, and late carbonate and/or sulphate open space infill. Magmatic fluids are interpreted to have utilised the same plumbing system as the late stage feldspar porphyry intrusive, and then migrated into the Roamane Fault which was dilated by; dextral rotation on elements of the transfer structure, normal faulting, and refraction around the competent footwall hornblende diorite. Bonanza gold is localised in a jog in the Roamane Fault, hangingwall splits and at intersections with cross structures. Bulk low grade Stage I gold has been deposited by the mixing of magmatic fluids with cool gas condensate waters, whereas high grade Stage II gold mineralisation resulted from the rapid quenching of mineralised magmatic fluids by oxygenated groundwaters.

Jan 1, 1995

By A Llewellyn, M Varvari

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

Jul 1, 2013

By B Mack

The cost of water treatment is now more than ever a major consideration for maintaining an environmentally and economically sustainable mining operation. As an industry, we often have to consider water sources that are highly impure and difficult to treat. We are also discovering the value of our waste waters in this regard and using new and improved methods and technology to reclaim and reuse water. In many instances, the water or waste water to be treated is highly acidic and saturated in sparingly soluble salts. Conventional systems used to liberate this type of water typically involve high doses of lime with large volumes of waste sludge produced, and are comparatively complex to operate, to pretreat the water in order to reduce scaling tendency on the reverse osmosis stage. However, if the water is considered valuable for reuse, then why not avoid difficult and cumbersome pretreatment processes and treat the water at low pH to keep the sparingly soluble salts, metals and other dissolved species in solution. This paper describes a patented technology that uses and successfully proves this concept as a cost effective option for certain situations. Results from a treatability study on an Australian groundwater are discussed, along with an economic comparison to a conventional method and discussion on full-scale potential.

Jan 1, 2009

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 J Morgan

Regular monitoring of surface deformation over mine sites is important for providing updated information to managers regarding geotechnical risks related to ground instabilities. This is particularly true in cases where unexpected or accelerating movement patterns are observed, as these trends may have implications related to worker safety within active mining environments, as well as continuity of ongoing operations. InSAR is an active remote sensing technique that uses radar satellite imagery to precisely measure ground movement. This technology has started to become a standard tool for monitoring surface stability in many different sectors, including underground and open pit/cut mining applications. In recent years the launch of satellites that collect radar imagery on a more frequent basis, coupled with advances in InSAR processing techniques, has improved both the extent to which movement patterns typical of mining operations can be characterized and the temporal scale on which results can be reported to geotechnical departments. As a result of these developments, InSAR monitoring can now better meet the operational needs of mine sites. An overview of the more recently launched satellites that have a particular relevance to the monitoring of mines is provided, along with an explanation of the InSAR tools that are the most valuable to mine managers and geotechnical engineers. First, broad differences between high resolution X-band imagery and low resolution (but freely available) Sentinel imagery are discussed. Second, the various InSAR tools and their particular applications for different types of mine sites and operations are covered, which include fast delivery deformation maps for short-term reporting, multi-interferometric algorithms for longer-term analyses and rapid movement tracking (RMT) for emergency monitoring or high-risk situations. The ability of the technology to resolve 2D and 3D movement is also touched upon. Practical examples of InSAR application over a variety of mine sites will be presented, as well as surrounding hazards including landslides, to illustrate how InSAR can help provide geotechnical engineers with a picture of surface stability over the full mine site and surrounding areas to help manage risk. CITATION:Morgan, J, 2018. Wide area mapping of ground instabilities from space: InSAR for geotechnical risk assessment and hazard monitoring, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 375–382 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By G Pitkin, D Sorley

The purpose of any consultancy is to provide a superior service for their client. Organisational structure is a key element in providing this service and differentiating between consultants.In an organic organisation the emphasis is on effectiveness, problem solving, responsiveness, flexibility, adaptability, creativity and innovation. Such an organisation is able to respond in a timely manner to change because employees are empowered to be creative, to experiment and to suggest new ideas. The process of innovation is triggered by employees throughout the organisation in a collaborative manner.Problem solving becomes a core competence of the consultancy. A multidisciplined approach arrives at superior solutions that are rigorous, holistic, achievable and often novel. It allows the mining consultancy to extract the most from a very talented and experienced team.This paper highlights the advantages of an organic structure for a mining consultancy and how to implement such a structure. It draws on examples of innovative problem solving from feasibility and strategic studies carried out in Australia and Africa.CITATION:Pitkin, G and Sorley, D, 2016. Organic management structure – its advantages in a mining consultancy, in Proceedings International Mine Management Conference, pp 155-162 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 22, 2016

By S B. Sheldon

Wall control programs tend to be expensive and consequently require financial justification in order to get approval for the expenditure required. The difficulty faced in getting this approval is that the outcomes of a wall control program are all subjective – a prediction of wall stability and what the wall would do with and without the program. Determining a net benefit is difficult and often justification of a wall control program is based on gut feel, history and a good selling campaign to build a perceived need.This paper outlines a simple solution to this problem by applying risk management principles to wall control. The process is to identify the risks to the operation associated with current wall conditions and then build a risk database for different potential scenarios for each risk. A financial impact is assigned to each risk scenario to complete the database. A consequence and likelihood analysis of each of the risks is undertaken and a formula applied to estimate the projected cost to the operation for the current risk profile. The process is repeated for the predicted wall control conditions after the application of the wall control program. A successful wall control program will reduce an operation’s risk profile so this projected cost should be less than that calculated for the current scenario. The difference in the two projected costs is the value that the wall control program has produced and this value can be used to determine the net financial benefit potential for the wall control program.This methodology can also be applied to other improvement programs that focus on risk reduction such as vibration control.

Nov 8, 2011

By W J. Shaw

Mining operations must become more predictable to overcome the volatility that has characterised the mining industry. Comparisons of production against predictions will become more consistent as mining operations merge and expand, as personnel move from site to site, and as public reporting of reconciliations becomes more prevalent. More consistent approaches are already being seen in the industry using the terminology used in this paper and elsewhere.Examples are provided that show how use of the waterfall chart as a reconciliation management tool can provide objective analysis to improve practices.Geometallurgical modelling is becoming more useful and will continue to do so as we move from a few bulk samples to better interpretation of material properties from geological mapping and drill sampling. Reconciliation has evolved to the stage where predictions of geometallurgical properties to optimise mill performance, and of geotechnical properties derived from better 3D geological models, should also be reconciled.CITATION:Shaw, W J, 2014. Reconciliation – outcomes and expectations, in Proceedings Ninth International Mining Geology Conference 2014 , pp 123–128 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By G Campbell-Cowan

Much has been written about the fact that most transformation efforts disappoint. This paper addresses factors that should be taken into consideration in planning and implementing transformation programs to ensure success.In 2009, St Barbara commenced a transformation program to address issues of chronic poor quarterly operational performance; financial pressure caused by the unreliable operational performance; and an inability to develop business plans with integrity and to reliably deliver on the plans. As a result of a number of years of disappointing operational performance, St BarbaraÆs culture was not conducive to business success.This paper uses lessons learnt during St BarbaraÆs transformation program to highlight key characteristics of change programs that can generate significant sustainable benefits. While there were many benefits from the transformation program, the most significant impacts of St BarbaraÆs program have been transformation of the companyÆs culture and capability of people as business leaders; the establishment of a business systems framework to guide the design and development of systems; and developing support functions, for example centralised procurement and supply chain, business improvement and technical services.CITATION:Campbell-Cowan, G, 2012. Business transformation - Lessons learnt for successful change, in Proceedings International Mine Management 2012, pp 135-142 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 20, 2012

By M Ozkayhan, N Arslan

"The Efemçukuru underground mine in western Turkey is an intermediate sulfidation, epithermal gold deposit. The bulk of the mineral resources and all of the mineral reserves lie within the Kestanebeleni (KB) vein system. This system comprises four spatially-distinct mineralised zones: the south ore shoot (SOS), the middle ore shoot (MOS), the north ore shoot (NOS) and the KB north-west ore shoot. Production currently occurs only in the SOS, MOS and NOS zones. The gold mineralisation is very fine grained and occurs as free grains in quartz and carbonate, and as inclusions in sulfide minerals. Gold is recovered as part of a sulfide concentrate by flotation methods. Though hosted in the KB vein, the gold mineralisation is not evenly distributed within the veins. Definition of its occurrence is totally dependent on diamond drilling.Diamond drilling at Efemçukuru is done with its own equipment and staff, all managed by the mine geology group. The process over the mine’s six year production history incorporates continual improvement with an innovative approach by focusing on the following: drill team organisation career development and training product research and effective equipment management cost reduction planning and scheduling of development for drill stations.Over 40 000 metres of mostly BQ size core are drilled annually by three drill rigs at a cost approaching US$35/m.The planning and execution of the drilling pattern depends on the configuration of the ore shoot and the planned mining method. Ore extraction is mainly by drift and fill mining augmented by about 15 per cent longhole stoping. The drilling of a specific area is scheduled to be finished 3 to 8 months prior to mining. This scheduling is sufficient for short-term grade model updates and any needed changes to the planned development or stope sequencing prior to planned production from the stope area.CITATION:Arslan, N and Ozkayhan, M, 2017. Diamond drilling at Efemçukuru gold mine, Turkey – a case study on the benefits of timely and cost-effective drilling to short-term planning, in Proceedings Tenth International Mining Geology Conference 2017, pp 285–290 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 20, 2017

By J Theiler, B Beamish

The presence of reactive metal sulfide minerals in waste rock contributes to the hazard of spontaneous combustion in dumps, as these minerals react with air and water entering the dump at ambient temperatures to form various mineral products and significant heat. This reaction series can also be an initiator of self-heating of carbonaceous material present in the waste rocks if sufficiently high temperatures are reached. Characterisation of these reactive minerals has primarily been to assess the risk of acid mine drainage, which is not necessarily an indicator of spontaneous combustion risk. No systematic testing procedure has been adopted by industry to assess the spontaneous combustion propensity of the waste rock. As a consequence, the principal management strategy for spontaneous combustion has been a reactive approach of dealing with events as they arise.Recent advances in adiabatic oven-testing have enabled more definitive assessment of the spontaneous combustion propensity of coals, including the quantification of the accelerating influence of reactive pyrite (Beamish and Beamish, 2011, 2012; Beamish, Lin and Beamish, 2012). This same test procedure has been used to assess the self-heating performance of metal concentrates and is therefore amenable to assessing the metal sulfide oxidation process from low ambient temperatures. The data obtained from such testing can be used to quantify the more prone waste rock sequences of a mineral deposit in advance of mining. This enables appropriate management planning for emplacement and long-term storage of waste rock in dumps.CITATION:Beamish, B and Theiler, J, 2016. Characterising the spontaneous combustion propensity of waste rock, in Proceedings Life-of-Mine 2016 Conference , pp 93–96 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

Rio Tinto Iron Ore (RTIO) manages eleven mines in the Pilbara region, Western Australia. Three of these mines have previously or are currently mining black shale that contains varying amounts of pyrite. Several new deposits currently being evaluated and existing mines that may progress below water table in the future, will also encounter this waste material. The black shale presents not just an acid rock drainage risk but also a spontaneous combustion risk. This paper presents the black shale management strategy and provides an overview of the relevant activities undertaken by RTIO. The strategy can be divided into two components which firstly involve defining the risk and secondly involve managing the risk. The mineral waste management plan is used to identify specific mineral waste hazards by:geochemical characterisation of waste material,undertaking mine site specific risk assessments,characterising the receiving environment,identifying sulfidic boundaries in geological and mining models,quantifying the amount of sulfidic material in medium and long-term mine plans, anddesigning and sequencing black shale waste dumps. Once a mine exposes black shale the Spontaneous Combustion and Acid Rock Drainage management plan is used and the major activities are: regular site meetings with a representative from every group that works with black shale;compliance with safe working procedures for site specific and detailed activities;regular training;the use of specific explosives to prevent premature detonation;ongoing geochemical characterisation;acid water management, monitoring and analysis;regular internal and external auditing of procedures and practices; andclosure planning assessments and preparations (ie cover trials, geochemical void modelling, geochemical waste dump modelling). The success of this holistic strategy is evident by the awareness of personnel within the business, thorough understanding of the geochemistry and by undertaking proactive management of black shale during mining. The strategy and management plans adopted by Rio Tinto Iron Ore have activities that other mine sites with potentially acid forming material may like to consider implementing.

Jan 1, 2009