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By H R. Pein

"The Corridor Sands deposit is situated approximately 190 km north east of Maputo, Mozambique adjacent to the paleo-mouth of the Limpopo River. This deposit is one of the worldÆs largest known economically viable resource of titanium, accounting for approximately one third of the global resource. As part of the pre-feasibility and feasibility study for development of the Corridor Sands project, various geological and geotechnical investigations were undertaken, selected results of which are presented in this paper. These investigations have enabled a detailed understanding of the material characteristics of the orebody as well as the tailings materials, such as the fines, to be developed. These material characteristics have had a significant impact on the selection of the mining and disposal methods currently being implemented."

Jan 1, 2001

By N Elith

The explosives demolition of a post-stressed, steel reinforced, concrete road bridge in Australia’s capital city, Canberra. The bridge was 50 m from the new replacement bridge, 320 m from community structures and within five kilometres of the national parliament buildings. The job required multiple overlays of risk assessment, public relations, safe work procedures, specialised blast design, environmental predictions and flyrock controls. Project stakeholders included Worksafe, Roads ACT, bridge owners, consulting structural engineers, community groups and road users. The bridge precincts, including a major road underneath, had to remain operational to peak traffic in the days leading up to the demolition. The break-up and removal of debris had to be executed in just two days from Friday to have the road beneath re-opened for Monday morning city-bound traffic.In Canberra, all explosives demolitions are now viewed with particular caution after a demolition in 1997, during which a young girl was killed. Any approval requires that Explosives Regulations, AS2187 2006 and Worksafe processes are satisfied, and a convincing case presented for blasting as a safe and viable option.Our design used specialised shaped cutting and blasting charges to sever in situ concrete beams and tendons and to shatter components of the stressed concrete bridge assembly. We include comments on structural engineering reports dealing with pre-weakening mechanisms. The benefit of pre-weakening is that it reduces the amount of explosives needed to safely complete the job and facilitates quick removal of debris after the shot. The complementary skills of the team, each one an expert in his field, resulted in a highly successful demolition, praised by authorities as an outstanding example of controlled use of explosives.

Nov 8, 2011

By O Jones

Longstanding occupational health challenges of the underground hard-rock mining sector require both an analysis of historical data to assess evidence of linkages between the source of the problem and subsequent illnesses, as well as investigating the means by which health risks to workers can be eliminated or minimised. This paper refers briefly to a recently established National Health and Medical Research Council (NHMRC) sponsored Epidemiological Study into the incidence of Lung Cancer, contracted by mineworkers in Western Australia (WA) due to the inhalation of diesel exhaust fumes from 1996 to 2012. Thereafter it reviews current knowledge of the nature of the challenges facing those responsible for the health and wellbeing of underground hard-rock miners in WA, commencing with the recent categorisation of diesel exhaust as ‘Carcinogenic to Humans, Group 1’, by the World Health Organisation’s (WHO) International Agency for Research on Cancer (IARC). An attempt is also made to explore how the challenge has changed with the adoption of more advanced engine technologies, including the increased generation of ultra-fine volatile organic and other nucleates, submicron carbonaceous agglomerates and toxic gases.The compounding effect of using the mine decline access entry as both the primary ventilation intake and haulage-way is also discussed, as is the need to develop a more appropriate metric for regulating diesel engine emissions. Finally the paper refers to ongoing in-mine research pursued by the National Institute for Occupational Safety and Health (NIOSH) at its Diesel Laboratory in an underground limestone mine near Morgantown in the USA.CITATION:Jones, O, 2015. Diesel exhaust and the underground miner in Western Australia, in Proceedings The Australian Mine Ventilation Conference, pp 167–172 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By M Revell, B Sainsbury, D Sainsbury

This paper extends the existing knowledge associated with the design and placement of prefabricated pastefill barricades through a consideration of asymmetric drive geometry and conditions. The load capacity of prefabricated barricades and their failure modes are considered in relation to abutment geology and barricade geometry that includes curvature and span and drive geometry that includes abutment angles, haunch angles and misalignment. Design charts are provided for typical barricade sizes to provide general guidance for design capacities and optimising location placement based on asymmetric drive geometry. A recent barricade failure is considered in relation to the drive geometry and the potential impact it had on the installed capacity.

Nov 29, 2022

By E Hernandez, I Agustian, W Kusumohastuti

PT Freeport Indonesia is completing the first underground gyratory crusher excavation at their Deep Mill Level Zone (DMLZ) mine located in the mountains of Jayawijaya, District of West Papua, Indonesia. DMLZ is an underground block cave mine with an expected output of 80 000?t/d and a scheduled production start in 2015.In order to deliver crushed ore to the mill through the existing conveyor belt, the DMLZ block cave mine will construct two 1000?kW 1.6?×?2.3?m gyratory crushers with their own respective ore flow conveying systems underground. Each crusher is composed of top, middle, and bottom chambers with an ore bin. This system includes a series of high capacity conveyors approximately 5 km in length including transfer stations and support facilities.The development methodology required a combination of lateral development by jumbo drilling machines and vertical development by mechanised raise climbers (MRC) due to the complexity of the chamber design.This paper will discuss the project scope, design and development methodology, ground conditions, innovative survey controls, and the challenges faced due to the remote location.CITATION:Hernandez, E, Kusumohastuti, W and Agustian, I, 2014. Excavating the first underground Gyratory Crusher at the Deep Mill Level Zone mine, PT Freeport Indonesia, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 43–50 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

By D Cliff

"Recent underground coal mine incidents have again raised the issue of: under what circumstanceis it safe for personnel to re-enter the mine? Mine rescue guidelines make recommendations aboutthe limits in terms of the circumstances, lives at risk, no lives at risk and training exercises. Theseare based upon percentages of the upper and lower explosive limits. Many factors infl uencesett ing limits for safe re-entry. These include: the representativeness of the sampling location(s),the rapidity of gett ing an underground sample analysed and the rate of change of the atmospherebeing monitored. Value judgements based upon these parameters will then infl uence the sett ing ofa trigger point based upon per cent explosibility. This raises the question of how the percentage ofthe lower or upper explosive limit is established. It is easy to defi ne this when the sampling pointdata sit on the fresh air limit line. However - what value is used when the sample sits somewherein the body of an explosibility diagram? This paper explores the various options and illustratesvarious pitfalls and problems that are faced in making such a determination. These include howthe data are represented and the assumed knowledge of those doing the interpretation."

Jun 1, 2012

Batch centrifugal gravity concentrators have become standard equipment in gold grinding circuits for recovery of gravity recoverable gold (GRG). The downstream benefits of installing a gravity circuit are well understood, and in general, if there is a reasonable amount of GRG in the ore, a gravity circuit is usually installed. The benefits of gold gravity recovery have also been well documented, with a large database of successful case studies. As well, predicting production scale gravity recovery results ahead of installing gravity has become a common practice. The missing link between lab and full scale has always been the ability to predict the recovery benefit of installing gravity ahead of actually doing so. Being able to predict the recovery benefit in advance would help an operation in assessing the economic benefit and help justify the capital costs of the gravity circuit with much less uncertainty.

Aug 1, 2010

By S Kowalczuk, S V. L Barrett

The potential for adverse surface settlement during tunnelling in soil and rock poses a significant risk to the successful completion of any tunnelling project. Undesirable ground movement may lead to unacceptable level of damage to surface infrastructure, buildings and the environment, resulting in safety concerns as well as causing significant delays and costs to a project. One of the empirical methods which is commonly used to predict surface settlement in the early stages of a project’s development is the volume loss approach as described by Mair, Taylor and Burland, 1996. This method was developed for use in soft ground; however it has also been applied in weathered and soft rock to provide an initial indication of potential surface settlements along a proposed tunnel alignment. This paper presents some initial thoughts on the use of this method in weathered and soft rock and the associated limitations which need to be taken into consideration when interpreting the results. This includes complex weathering profile cases where the strength and stiffness of the ground does not necessarily increase with depth.CITATION:Kowalczuk, S and Barrett, S V L, 2014. Initial thoughts on application of the volume loss approach for estimates of surface settlement due to tunnelling in weathered rock, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 641–646 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By R Cooksey

The Globe-Progress Mine is an open pit gold mine that is part of the larger Reefton Goldfields deposit located on the West Coast of New Zealand. The regional geology comprises a series of north to south oriented fold structures that have undergone post-deformation mineralisation. The structural geology within the mine itself is more complex, with major shears hosting numerous high-grade mineralised quartz shoots and splays that have been historically mined.The selective mining of ore within the pit is challenging due to the orientations of the hanging wall and footwall areas of the main Globe shear zone, the lithologies of these areas which range from highly brecciated and sheared material to competent mineralised host rock, and in the hazards presented by the numerous old historic underground workings. The coordination of drilling, modelling and excavation of the ore requires careful planning to maximise recovery whilst operating with the pit design boundaries.Grade control packages are custom designed to reflect the orientation of the footwall and hanging wall mineralisation. The shear material in the footwall zone dips between 60° and 70° and requires angled drilling whereas the footwall mineralisation is contained in shallow dipping quartz veins sub parallel to bedding and can be vertically drilled to best intercept the mineralisation. Ore excavation is directed so that the contact between the footwall and hanging wall is mined in the correct direction so that any non-visual ore contacts can be safely mined and that the ore-waste dilution is reduced.The ongoing grade control and selective mining of the Globe Progress deposit continues to deliver high grade ore for processing by ensuring that waste and dilution of ore is reduced and that recovery is maximised.

Aug 22, 2011

By M Wortley, J Korteniemi, D La Rosa, L Rajavuori

Geometallurgical modelling of an orebody provides benefits to a mine by gaining a better understanding of the ore characteristics and how they affect the performance of the concentrator. With this knowledge, plant operating conditions can be adjusted to optimise throughput and recovery in advance of the arrival of particular ore types. Therefore, it is extremely important that the origin of the ore being processed is known as accurately as possible. Depending on the homogeneity of the ore characteristics, reliance on assumptions about stockpile residence times, scheduling and material handling can render the best geometallurgical models useless.The solution adopted at Agnico Eagle’s Kittilä mine was to utilise Metso SmartTags™ and in-house expertise to develop a system that continuously and accurately links geotechnical and lab data from the mine to the performance of the plant. This application presented several unique opportunities and challenges. For example, this was the first installation of a SmartTag™ system for geometallurgical modelling in an underground mine. Challenges included the fact that the system installation is routinely subjected to temperatures below -20°C.The system was installed and commissioned in early 2013 and has been operating continuously since. Kittilä has begun to see the benefits of the system, with an increased understanding of how different ores are processed in the concentrator. Other advantages include the ability to alert operators about the arrival of difficult ores and a better understanding of the ore handling systems.This paper describes the installation and use of the system at Kittilä and details some of the geometallurgical relationships that have been developed using the data collected so far.CITATION:La Rosa, D, Rajavuori, L, Korteniemi, J and Wortley, M, 2014. Geometallurgical modelling and ore tracking at Kittilä Mine, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 291–298 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

In practice a sampling solution is a compromise of many requirements: the sample should be representative; the sampling system should also be reliable, less than 95 per cent availability restricts the use of the assayed sample for process control purposes; no sample is the worst sample, and investment costs and installation space/layout are frequently a restriction. For instance, online X-ray analysers for process control introduce a delimitation error by the nature of X-ray physics. Thus only in special cases a relative accuracy better than three per cent relative, as one standard deviation, is achieved. A sampling system for process control needs not to be, as representative, for so many sample properties, as one for composite laboratory analysis samples. Sampling system maintenance is also an important issue. There are many sampling systems in the industry which have been difficult to maintain and are in disuse for lack of resources or incentives to keep them running. Pierre Gy developed the most generally accepted sampling theory. One of the main principles is that all particles in a one-dimensional process stream should have equal chances of being included into the sample. A correctly designed and operated transversing cutter comes close to this goal but has limitations in temporal representativity. For slurries an acceptable solution in many cases is to use a fixed vertical cutter(s) in a position where the slurry is well-mixed by turbulence and other means. For online analysis, reliability problems are mostly related to faulty design or installation of the piping system to the analyser. Properties of material processed, process flow sheet and piping details before and after the sampler have to be taken into account when deciding on which sampling arrangement is appropriate. Guidelines and some solutions to these issues are presented in this paper.

Mar 1, 2010

By S Thomas, S Ricketts, R Hassell

Northern Star Resources (NSR) operates several operations utilising narrow vein stoping operations in the Kundana area. Stope dilution performance is variable across these operations, with unplanned dilution reducing individual stope economic viability, increasing risk to personnel and machinery operating in and around the stope and delaying the overall stoping sequence. Technical investigations were undertaken to objectively understand the variables which had the largest impact on stope performance and then use the findings to help develop mining strategies to reduce dilution. A stope reconciliation process was developed to compile key stope performance information such as stope design parameters, geotechnical and drill and blast factors. These were compared against the measured dilution. Production targets necessitated a high turnover of stopes in the operations, and hence a requirement for an expeditious process and mine design software with automated tools. The output of these results, together with numerical variables from geological, geotechnical and drill and blast data were analysed via multivariate regression. The analysis identified the factors with the greatest influence over stope dilution, and a forecast model was consequently created. Confidence was gained in the model when the subsequent stopes performed in line with prediction. Different drill and blast designs were subsequently trialled and found to reduce dilution. The model was then updated with the new practices, facilitating further regression analysis to identify revised key controlling factors. The subsequent production results however, displayed a poor correlation with the prediction from the revised model. Inconsistencies in drill and blast designs and execution were identified as key factors in the dilution performance. This was an important finding as the correct implementation of the design is critical and this has become a key focus for future stoping. Overall the technique presents an objective process to identify causal factors of stope dilution resulting in improved economic metrics for stope production. The process will be applied to other similar Northern Star operations.

Mar 15, 2021

Continuous improvement in environmental management assists in the achievement of sustainability goals for the mining and processing of minerals. The use of regular internal environmental audits (scored or unscored) which form an integral component of an Environmental Management System (EMS), provide demonstrable evidence of this improvement. The audits described in this paper involve working with site personnel to develop and implement major improvement projects, providing advice on how to improve environmental practices and facilities, and disseminating innovative ideas and practices across the site and to other operations within the same group. Essentially the lead auditor assumes the role of a æskills coachÆ as opposed to a æpolicemanÆ, which is quite often the case for many audits. The audit process has been developed from involvement with a number of major coal mines in the Hunter Valley, where regular internal environmental audits have been undertaken every two to three months, over periods varying from 18 months to five years and more recently, with a metalliferous mine in the Northern Territory. Examples of the benefits of improved environmental performance (driven by the audit process) to sustainable development are provided. The auditing process as described is applicable to metalliferous mines, the processing of mineral ores, coal mines, coal handling and preparation plants, quarries, and oil and gas projects.

Jan 1, 2004

By R Burke, G Ramage, C Donnelly

Over the decades, Redpath has undertaken a multitude of tunnelling and underground excavation projects for civil and mining clients both domestically and internationally. These projects have been undertaken through varying strata conditions with differing excavation methods in remote locations and in central business districts.With the recent turbulent nature of the global financial environment, project drivers have been challenged with the emphasis being placed on methods to gain early access to orebodies, rapid development techniques, lower capital costs and reduced labour requirements to name a few.A number of mining companies seeking to achieve these objectives have commenced the journey to better understand the operational constraints, challenges and opportunities that may be available with the use of alternative excavation methods.The development of safe and effective alternative excavation methods that comply with both domestic and international mining legislation and regulatory requirements is a challenge the industry needs to embrace. Given the current cost pressures being faced by the Australian mining industry, some alternative excavation methods offer the potential for longer term sustainability and rapid development of resources.More recently work has been undertaken on a project that challenged the norm and implemented an alternative excavation method with the use of an excavator with a rotating drum cutter head.This paper will review this recent project and provide technical and operational insight into some of the challenges faced in implementing an alternative excavation method in the metalliferous industry.CITATION:Donnelly, C, Ramage, G and Burke, R, 2014. Challenging the norm – alternative excavation method in mining, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 187–190 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

By G Deans, M Longbottom

OZ Minerals’ Carrapateena mine is one of Australia’s newest ‘greenfield’ mining deposits. It will be a 4.25 Mtpa sub level cave underground operation, with an estimated mine life of 20 years. The integration of stakeholder values to inform project development influenced the social and environmental outcomes. A Native Title Mining agreement was developed in 12 months. Project primary approval was obtained 12 months from submission, with achievable licence conditions and one public comment. The project moved from a Pre-feasibility Study in 2016 to construction in 2018. Following recent international dam failures, the Tailings Storage Facility (TSF) was a focus for Government approvals and stakeholder engagement. Significant effort was made into understanding the science around potential effects, impacts and risks. A leading practice Impact Assessment Framework that identified Sources, Pathways and Receptors was applied. A process of failure mode identification and layers of protection analysis was undertaken for robust design controls at each stage, while simultaneously transitioning between downstream and upstream discharge arrangements. Participatory selection of the TSF site and design layout was critical in managing project costs and environmental constraints, and in incorporating cultural heritage constraints and technical risks.

Jul 1, 2021

By J Rutter, D La Rosa, P Walters, M Scott, L Keeney

Bulk ore sorting technologies, whether surfaced based or penetrative, have seen an increased uptake by the mining industry for preconcentration application. As with all technologies, going through the technology validation process is key to de-risking the operationalisation of the technologies and to demonstrate and confirm predicted value propositions. The ability to laboratory calibrate cross-belt bulk sensors is standard practise for sensor vendors, however transitioning the technology from laboratory to real-world application is a non-trivial process. The industry has taken two main approaches to trialling and validating bulk sensing technologies in operational environments, namely:  Construct an off-line pilot facility at scale, or  Install bulk sensing systems on production conveyors Each of these two approaches have significant advantages and disadvantages and require different experimental design programs and analysis methodologies. Consideration of material movement, heterogeneity degradation, logistical requirements, and financial investment all factor into which approach is most suitable for an evaluation scenario. CRC ORE in partnership with mining companies, have conducted several bulk sensor pilot trials utilising different sensor technologies employing each of the two main approaches outlined above. This paper describes the challenges faced, learnings obtained and outlines a position on how to transition bulk sensing technologies from the laboratory into the operating environment. The case studies presented cover a range of commodity types in both open pit and underground operations.

Nov 10, 2020

By C Rule

In 2003, Anglo Platinum, in a joint development with Xstrata Technology, installed the world’s first 10 000 litre IsaMillTM in a concentrate regrind duty at the Western Limb Tailings Re-treatment Plant. The success of that installation was the enabling event for Anglo Platinum to proceed with a substantial investment in horizontal stirred milling technology. Since 2006 an additional three IsaMillsTM in concentrate regrind duties and a further 18 IsaMillsTM in the more technically challenging coarse grinding mainstream applications, have been commissioned in group Concentrator operations - bringing the total number of IsaMillsTM installed in Anglo Platinum plants to 22.A collaborative approach between Anglo Platinum and Xstrata Technology towards improving milling efficiency and reducing operating costs, through internal mill component wear optimization and operating recipe development, has resulted in further improvements in the overall success of IsaMillsTM in the flow sheets of many Anglo Platinum operations. The addition of IsaMillsTM in the Anglo Platinum flow sheets has improved plant PGM recoveries by as much as 5%.This paper explores the improvements made to the IsaMillsTM flow sheet and mill internal design and shares some of the operating experience with IsaMillsTM technology in Anglo Platinum

Aug 8, 2011

By K H. Esbensen

Optimisation of a real-time at-line monitoring system for control of industrial granule coating quality is presented. The system is based on a fluorescence imaging system, because fluorescence originates in the interiors of enzyme granules but is significantly quenched by a polymer coating (which is needed due to environmental precautions). We have developed an image analytical system for direct prediction of coating quality, which is based on application of the Angle Measure Technique (AMT) for image complexity characterisation; AMT is briefly described. The first part of the presentation addresses pixel sampling strategies within a digital industrial image, inherent in application of AMT, in which the unfolded image is regarded as a one-dimensional object in analogy with 1D process sampling in Theory of Sampling (TOS). The effects of random, stratified and systematic pixel selections in the unfolded image are evaluated. Also factors such as the fraction of image pixels and the effects of specific unfolding strategies (there are three principal strategies, termed æchopÆ, æsnakeÆ and æspiralÆ respectively) are investigated. It turns out that unsuspected artifacts are sometimes produced, related to the specifics of the unfolding procedure, which interferes with a straightforward 1D TOS process sampling analogy. These artifacts have a wider interest û among others, for 2D sampling û and therefore receive special attention in this presentation. The optimal pixel selection strategy for the AMT algorithm is found to be systematic or stratified sampling (not surprising according to TOS) of 500+ initiating points, but need to be unfolded in the novel spiral- or snake-wise fashions in order to effectively counteract these artifacts. This also has a general impact on various suggested standard schemes for 2D grid-sampling, among others, from the geoscience realms. The second part of the presentation is directed towards optimal image analytical sampling of a continuous series of fluorescent images (imaging of conveyor belts of æinfinite lengthÆ), ie optimisation of process image sampling. The minimum number of images needed to uphold a sufficiently good on-line estimate of the quality control (QC) parameter in question is found to correspond to the relatively high sampling rate of 15 - 20 per cent, which can be shown to be related to an intrinsic very high measurement error level (25 per cent) of a mandated analytical reference method.

Jan 1, 2005

By M T. Grigoleit, M S. Schneider

The iron ore industry in Australia has, in recent years, experienced an unprecedented growth phase. But now that major expansions are moving into the operation phase, new challenges have emerged. Whereas initial planning may involve a few modelling studies, ongoing performance monitoring and improvement requires a different, more intense approach. This is especially important in the face of changing factors such as commodity prices, exchange rates and labour markets. Response time is key. As a mining operation proceeds from initial planning to daily operations, the time window for analysis shortens, going from months to weeks to days as the business matures.Simulation models and analysis tools are typically built and run by specialists in the planning phase, but then what? The investment has been made, but realised only once. What if further analysis could be carried out in-house, re-using existing models using up-to-the-minute data? Can we create virtual mines that run in parallel to live operations that allow computers to identify areas of a value creation or operational improvement? These questions can be answered by the innovative application of big data, simulation and predictive analytics. The future will be having this all integrated into one platform that offers, for the first time, an opportunity for non-experts to apply existing modelling and analysis assets – combined with live data – to deliver support for continuous improvement, and the ability to respond quickly to external changes in the best possible way, before they become big problems. These techniques will represent a step change in the ability for operations to maximise efficiency and will underpin the intelligent operations of the future. These issues are addressed in this paper.CITATION:Schneider, M S and Grigoleit, M T, 2015. Maximising productivity through big data, simulation and predictive analytics, in Proceedings Iron Ore 2015, pp 475–480 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

Mine site rehabilitation is the repair of the disturbance caused by mining on the immediate mining area and also on the surrounding environment. The long-term objectives of rehabilitation can vary from simply returning an area to a safe and stable condition, to restoring the mined land to a state as close as possible to its pre-mining condition, capable of being self-supporting and having a beneficial final land use. This paper investigates the importance and benefits of environmental planning, in particular for rehabilitation, and how input into daily operations can allow mining to progress with limited impact on the surrounding environment. It will also identify some of the key mistakes currently made during mining which could be averted by implementing prior planning and incorporating environmental consideration into daily operations. A number of rehabilitation opportunities will also be detailed for the different stages of the life cycle of a coal mine.

Jan 1, 2007