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By D J Maconochie

The use of rock bolts as permanent support has been prohibited by client specifications in several recent large tunnel projects in Australia. The justification for this appears to lie in concerns with proper and verifiable installation procedures rather than concerns with the intrinsic durability of the corrosion protection systems. However, in civil tunnels, preventing the use of permanent rock bolts for long-term support results in the use of cast in place concrete lining which in some instances would otherwise be unnecessary.

Mar 8, 2011

Mining is still a significant economic activity within the Hauraki District. The Martha project is particularly significant. Estimates are that in the order of 850 direct and indirect jobs are derived as a consequence of the Martha project within the Waikato Region. The Resource Management Act 1991 (RMA) is New Zealand's primary piece of environmental legislation. It sets out to provide the framework for the control of the use, development and protection of almost all physical and natural resources. Minerals are excluded from the sustainability requirements of the legislation but as mining invariably involves the use of land, all the other elements of RMA apply. The Council's role in dealing with mining changed with the introduction of RMA. It became responsible for administration of those matters that fell within the functions set out in section 31 of the RMA in respect to existing authorisations. Mineral development needed to be considered in the development of the District Plan that the Council is required to prepare. Implementation of the Act has been a challenge for not only local government but for many industries and resource users since it came into force in 1991. There have been, and are, differing views on both the way it is administered and its intent. The Hauraki District Council has been at the forefront of some of the challenges that are a consequence of the Act. Its reactions to these challenges have been consistent. It treats mining in the same why it treats any other industry. At times this approach has not been understood and without challenge from sections of the community.

Jan 1, 2000

By J Gotte, C Morley, J Froud

Newcrest Mining LimitedÆs Telfer Mine is a world-class gold and copper producer, situated in the Great Sandy Desert, in the north west of Western Australia. The mine has a number of distinctive characteristics such as being one of AustraliaÆs most remote mine sites, being within 270 km of the hottest town in the southern hemisphere (Marble Bar) and having been shut down and reopened after a two-year feasibility study. The construction of a new plant and reopening of the mine gave Newcrest the opportunity to review their mining practices and systems including the opportunity to incorporate reconciliation as a core process. Telfer is now well on the way to being one of the largest gold and copper concentrate producers in Australia. When the mine reopened in June 2003, Telfer implemented SnowdenÆs Reconcilor software system to facilitate reconciliation of geological models, production data and plant measurements. The system was implemented on site in June 2004, as a web-based information management system, integrating other existing mining and plant software packages. It continues to provide an auditable process and consistency of data, providing ease of analysis with standard and customised reporting. This paper provides a case study of the reconciliation system implementation at Telfer. It outlines the consolidation of a number of management systems into one centralised system that can be used to compare and reconcile the tonnes and grades from the mine through to the mill. The authors outline the key estimates and measures that are used for reconciliation at Telfer, detailing the characteristics of the system used to capture the information and the benefits that have been gained through the use of a rigorous reconciliation process on a complex orebody.

Jan 1, 2007

By L Salvestro

Ventilation on demand (VOD) has been demonstrated to significantly reduce operating costs for ventilation fans, by reducing fan output to meet demand. The most effective method for reducing operating costs is to use variable speed drives to adjust the speed of ventilation fans as required – this achieves significantly larger power savings that damper or vane control alone.However, this mode of control will significantly increase the number of speed cycles the ventilation fans will experience. Fabricated impellers have a limited number of start stop cycles based on the materials and method of construction, and the operating stresses due to centrifugal forces. This means that fans experiencing constant or regular speed changes will experience a reduced fatiguelife compared with fans that are run at constant speed.The fatigue life of fans operated under various speeds using VOD is difficult to predict, as it is dependent on the magnitude of speed changes, and the frequency, which will be varied to meet demand. It is important to be able to estimate remaining fatigue life to assist in maintenance planning and avoid unplanned maintenance activities.This paper will review extensive VOD data on fan operating conditions from two primary mine ventilation fans. This paper will demonstrate how this data can be used to calculate accumulated fatigue and predict the remaining fatigue life, and how this compares with fixed speed or non-VOD controlled fans.The increased maintenance costs for the impellers will also be estimated, and compared to the operating cost savings using VOD, to determine if the savings outweigh the additional maintenance costs.

Oct 12, 2022

By M Salu

Ventilation control devices (VCD’s) and bulkheads are critical controls used for managing risk in underground coalmines. Following the Moura No. 2 mine explosion in 1994, the Queensland Mines Department required that the design of VCDs be based on live testing (such as in a mine testing explosion gallery) and more recently on numerical modelling using measured seal material properties. While the stipulated methods represent an idealistic solution, they are not practical to implement as solutions to daily challenges presented in underground coalmines.Not all VCD’s and bulkheads are placed in areas which have been mined to standard roadway dimensions. Operationally, VCD’s may be required to be placed close to intersections or require large dimensionally different areas (eg overcasts and pre-driven recovery road shutters) compared to the live testing or numerical modelling originally undertaken.This paper describes the various structural engineering methods utilised to account for the design of VCD’s where the operational requirements are non-standard. Siting and construction of VCD’s near the entry of cut throughs and geological structures requires additional design considerations. While VCDs constructed from a single material (eg sprayed mining plaster) are relatively straightforward to design, the addition of multiple openings (doors) or large pipes will complicate the structuralanalysis significantly.Temporary bulkheads used for the containment of grout such as for the construction of pre-driven recovery roads in coal mining have a significantly different risk profile to VCDs and should be designed accordingly. Recent failures and near-misses in such bulkheads have highlighted this issuefor the authors.The existence of an Australian Standard for Underground Mine VCDs and Bulkheads would go a long way to addressing many of the issues raised in this paper. Without a single, industry-accepted reference for VCD design, individual mines will have to continueto exercise their best judgements using whatever local expertise is available to them.

Oct 12, 2022

By K J. Ward, C N. Hatton, J Scalia IV, C A. Bareither, D L. Spencer

The mining industry is experiencing change in the governance of tailings facilities (TFs). Guidance and regulations across many jurisdictions contribute to this amorphous change. The Canadian Dam Association, Mining Association of Canada, Australian National Committee on Large Dams, and the Global Industry Standard on Tailings Management, produced by the International Council on Mining and Metals, are establishing guidelines for more rigorous industry governance. Evolving guidance regarding TFs is developing concurrently with a shortage of experienced tailings engineers, which adversely affects the resource base available to support new governance. This paper presents an updated semi-quantitative estimate of the impending resource shortage of qualified tailings professionals. Updates are provided herein for the estimated number of TFs worldwide, which included available data on active and inactive TFs, as well as the estimated labor resources required to service these facilities. The tailings labor shortage is discussed in the context of academic and professional training currently available to increase the quantity of trained personnel. This paper represents a discrete moment in time as contributions to the available information and inventories accessed continue to improve, but as of today are incomplete. However, the data and information included provide insight into the resource deficiencies currently within our profession, training and education opportunities to address those resource deficiencies, and a snapshot of a recent professional training course offered on mine tailings.

Jul 1, 2021

By H S. Pescini

A material aim when feeding ore blends into a processing facility is to reduce the variability of the properties of the feed material and to maximise the output, or throughput. At the Mining Geology conference of 2019, we presented a paper on optimal blending of coking coal given geological variability. The paper introduced integer-programming techniques to both maximise value and minimise feed or product variability. We discussed an application where the geological uncertainty is characterised using a normal distribution and exact solutions are readily obtainable using second order conic constraints in the mathematical model. Geological uncertainty is not always normally distributed, many properties will be characterised as log normal or some other skewed distribution. For example, copper can be some form of lognormal and Fe in Iron ore has a left skewed distribution. In this paper, we discuss some distribution free techniques to optimise the blends of plant feed or output given a quantified geological uncertainty. We discuss the sample average approximation method and how to set-up and apply the method to an ore blending problem. Evaluating a case study demonstrates that the explicit use of non-normally distributed geological uncertainty can better optimise feed into an ore processing facility and potentially add significant value. The approach is equally applicable to all mining and processing operations that blend material into a processing facility or directly into a saleable product.

Mar 22, 2022

By M McCurd, M Lynch, B H. Yin, S Mendoza, C W. Bumby, Y Iwasaki, B Rumsey

Iron and steel production is responsible for approximately 6.3 per cent of global anthropogenic CO2 emissions. Direct reduction of iron with hydrogen is a potential route for decarbonising the iron and steel industry. Extensive small-scale laboratory experiments have been performed to test the feasibility of hydrogen-direct reduction of iron ores sourced from diverse geographical locations. However, test results from the batch reduction of small-sample do not necessarily translate to continuous commercial-scale processes. Establishing a small-scale continuous test reactor for H2- DRI process is challenging, requiring substantial resources and investment. The limited availability of small-scale reactors that enable testing under relevant conditions has become a major obstacle for H2-DRI development, leaving a big gap between laboratory success and proof of commercial feasibility. Here, we report on the recent commissioning of a continuous counter-flow vertical shaft reactor, which has a processing capacity of 6 kg/hr iron ore pellets at up to 100 NL/min H2 flow. We believe this to currently be the largest H2-DRI facility in the Southern Hemisphere. In this talk, we will discuss the design and construction journey for this reactor, starting from the initial system design to the initial demonstration of H2 reduction of titanomagnetite ironsand pellets. This reactor now enables a range of research capacities, including the validation of laboratory results on a larger scale with practical operational variables, feasibility assessment of hydrogen direct reduction of different iron ores on a commercial scale; identification of scalability, sticking, and other potential issues before building a full-scale plant; and a viable solution for producing small-quantity DRIs for downstream melting investigations. Overall, this new research facility offers significant benefits for assisting the transformation of iron and steel production to a more sustainable and green industry.

Sep 18, 2023

By F Sandrone, J-P Dudt, J Zhao, E Paltrinieri

Tunnel boring machines (TBMs) excavation is nowadays more and more considered a valuable alternative to conventional tunnelling. As a matter of fact, thanks to its advantages such as greater rate of advance and safer working conditions, the application of TBMs has increased significantly in recent years. Despite the possible excellent performance of TBMs in favourable ground conditions, the advance rates could be significantly slowed down or even obstructed in limiting geological situations. This obviously traduces in potentially longer tunnel construction times and higher costs and, therefore, in a preference for conventional method. One of the major geological hazards encountered during tunnel construction, is related to the presence of fault zones or heavily jointed and fractured rocks. The most common geotechnical problems resulting from tunnelling in these difficult conditions include the instability of the excavation face, instabilities of side-walls producing large overbreaks on the tunnel profile, excessive deformations in case of squeezing grounds, frequently changing stresses in terms of magnitude and direction, high water inflows, etc. The decisions aids for tunnelling (DAT) is a model and a computer code that can be used to evaluate the influence of the uncertainties related to both the geological/geotechnical conditions and the construction process on final tunnel construction time and costs. In this framework, the DAT is used for assessing the effects that challenging ground conditions may have on tunnelling operations in terms of costs and delays. This is done by simulating the tunnel construction considering several geological profiles. The aim of the study is comparing different excavation methods (ie drill and blast versus TBM) in changing ground conditions along the tunnel alignment ranging from good rock, to very poor and fractured formations. The results show the impact, in terms of changing construction time and cost, of the excavation method versus the ground conditions.CITATION:Paltrinieri, E, Dudt, J-P, Sandrone, F and Zhao, J, 2014. Comparison of excavation methods in different ground conditions with the decision aids for tunnelling, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 573–580 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By A M. Lechner, S Arnold, M J. Gillespie, P D. Erskine, D R. Mulligan, A T. Fletcher, A Gordon

Mine ecological monitoring schemes are often conducted only to address compliance and in some cases do not have the sufficient statistical power or understanding of ecological systems to assess, quantitatively, the meeting of rehabilitation targets or mine impacts. Monitoring schemes for rehabilitation commonly rely on analogue sites or premining baselines (reference sites) to assess whether rehabilitation sites are ecologically similar and thus successfully rehabilitated. In the case of monitoring for mine impacts, if the impacted sites diverge from reference data, the site is considered to be impacted. Fundamental to any monitoring scheme is testing the sampling design to ensure that it can detect these differences if they are present through adequate sample sizes (ie statistical power). However, a good understanding of the ecological system is required to ensure that differences detected are ecologically significant. Modelling ecosystem properties can provide a quantitative understanding of how ecosystems change over time and space, in response to natural environmental variations and thus aid in determining significant ecological differences. Furthermore, modelling methods can be used to predict future ecosystem states. Within the ecological literature, guidelines for robust statistical monitoring designs and modelling methods exist but are not routinely being used in the mining industry. This paper uses simple examples to discuss: problems with current compliance monitoring methods; importance of robust statistical techniques; and how modelling can assist rehabilitation assessment and guide monitoring schemes. The aim of this paper is to describe general monitoring and modelling methods that could be potentially used for mine site monitoring and closure assessment. These methods are often considered by mining companies as an extra expense that provide little practical benefit, and the domain of academia; however, engaging these methods may be more cost-effective in the long-run than conducting untargeted monitoring schemes that give no confidence to regulators on whether rehabilitation criteria have been met. Furthermore, monitoring programs in mining contexts provide a good opportunity to better understand long-term ecological patterns and test the application of more rigorous modelling approaches as the life of many mines tends to be greater than ten years.CITATION:Lechner, A M, Arnold, S, Fletcher, A T, Gordon, A, Erskine, P D, Gillespie, M J and Mulligan, D R, 2012. Embracing modern ecological methods - Monitoring and modelling for mine closure, not compliance, in Proceedings Life-of-Mine 2012 , pp 25-32 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By W D. Ortlepp

Seismicity associated with deep block cave mining operations in hard rock can give rise to dynamic loading of the mining openings. A description is given of the source and damage mechanisms associated with such seismic events, and the possible demands placed on the rock support by the resulting dynamic loading. In addition, production level drifts are often subjected to large static deformations during mining. Appropriate support, able to sustain large static deformations, and capable of absorbing the energy released during dynamic loading, is described. The performance of these support types has been determined by means of large-scale dynamic loading tests, and large deformation static laboratory tests. Finally, a support system which is considered to be appropriate for extraction drifts in block cave layouts subjected to dynamic loading is described.

Jan 1, 2000

By A A. Puhalovich

The placement of chemically reactive mine wastes in mined out pits (æpit backfillingÆ) is increasingly seen by industry as best practice to manage long-term environmental risks. This is primarily because leaving wastes at the surface, or allowing pit lakes to develop, can result in unacceptable environmental risks. The costs and practicality of mitigation options such as installation of covers and community expectations of landform re-construction to achieve a post-mining, beneficial land use are also important drivers for pit backfilling.Pit backfilling can significantly reduce the post-closure risks to receiving environments, by minimising seepage due to tailings, acid/solute generating waste rock and/or salts derived from mine water treatment. Environmental risks are often highest where wastes are located close to the ground surface, due to relatively high rates of groundwater movement in near-surface aquifers and/or failure of engineered structures due to rainfall/erosion processes. Placement of these wastes at significant depth in pits, subject to mine planning and environmental assessment, can address these risks by increasing the path length and resistance from contaminant source to receptor, thus enhancing encapsulation of the wastes.Pit backfilling can also be cost-effective for mining companies. This is because existing pits are developed on the basis of an economic return and thus provide an opportunity to store tailings in an existing æengineered structureÆ at little or no incremental cost when compared with building and operating a new tailings or waste rock storage facility, often encompassing complex cover/drainage management systems. Key issues for consideration are mine planning, the long-term geotechnical behaviour of the wastes (eg consolidation of tailings which leads to release of acid/solutes in tailings porewaters), seepage rates to downstream receptors/agreed end point criteria and potential resource sterilisation. Internationally, mine closure guidelines are also showing a greater recognition of pit backfilling in the context of allowing mining companies to meet agreed post-closure land use objectives.In summary, pit backfilling can enhance the encapsulation of chemically reactive mine wastes and environment protection, and with agreement on post-closure beneficial land use, can also help to deliver post-closure benefits to communities.CITATION:Puhalovich, A A, 2012. Pit backfilling - Managing chemically reactive mine wastes and achieving rehabilitation objectives, in Proceedings Life-of-Mine 2012 , pp 279-286 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By R Wynn, N Stoitis, R A. Lauten, H Liang

At the Century mine in North West Queensland, MMG produces lead and zinc concentrates. The current production rate is close to 500 000 t of zinc per annum. Graphite is the main gangue in the orebody and a substantial quantity of chemicals are used to achieve an acceptable depression of graphite and other gangue materials in the current operation. In the future, it is anticipated that the content of graphite in the orebody will increase while the zinc grade will gradually drop. This scenario illustrates the importance of an optimised suite of flotation chemicals to maximise concentrate grade and recovery. As an alternative to the current reagent suite where dextrin is used to depress graphite, laboratory test work and subsequent plant trials were conducted with alternative depressants. These depressants facilitated both graphite depression and elevated zinc grades in the rougher concentrate. As an added benefit, it was also observed that the silica content in the zinc concentrate was reduced in the presence of the biopolymer selected for the plant trials. Results from both laboratory tests and plant trials will be discussed to illustrate how this change of reagent suite improved flotation yield at the MMG Century Mine.CITATION:Wynn, R, Lauten, R A, Liang, H and Stoitis, N, 2014. A change in graphite depressant to improve the recovery of zinc at MMG Century mine, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 179–186 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

Open pit mining at Bingham Canyon commenced in 1904 and about two billion tonnes of ore have been extracted since then. There remain just under one billion tonnes of ore in the pit and this will be mined by 2015. Because the porphyry system extends below the ultimate pit limits, Kennecott Utah Copper Corporation initiated a study in 1997 to determine the viability of underground mining. The study was initiated at that time because the results were to be used to compare the economics of a further pit expansion to that of an underground mine. If a pit expansion was viable then overburden removal would have to start in the near future. This paper is a summary of the work that was carried out for the underground study. Block cave mining was determined to be the most appropriate method to mine the deposit. Two block cave areas have been planned with a total production rate of 72 500 tpd. Additional sources of ore will come from skarn orebodies that are associated with the porphyry deposit. The geology of the deposits is described together with the geotechnical techniques that were used to characterise the rock in the absence of more detailed data that are normally available. A general description of the mine plan is given along with the reasons for selecting the particular methodology used. The study was completed at the end of 1998 and demonstrated the viability of underground mining at Bingham Canyon. Funds have been approved for further drilling and technical studies, which will lead up to a feasibility study in 2004/5.

Jan 1, 2000

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

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

Jun 22, 2016

Sishen uses a state-of-the-art tracking system to track material from its position in blast blocks through various stockpiles and crushers. Qualities are blended directly to the crusher as opposed to blending from stockpiles. This poses an interesting challenge to the planning department to simulate these conditions. The software used in these simulations are Whittle 4X and Maximiser for long-term planning, Xpac for medium-term planning and Mine Works Planner for short-term planning. Geological models and mine design layouts utilise Surpac. Sishen introduced Xpac a number of years ago; the system has developed and changed over the years. With the Sishen Expansion Project (SEP), which aims to utilise low-grade material, major changes to the planning process have to occur. SEP requires that the mine have two different plants, which utilise two different ROM feeds and have different beneficiation curves. Xpac is used to produce a rolling 18-month plan, which is as close to actual operations as possible. In order to do this, the simulations have to take into account the plants beneficiation curves, stockpile movements, hauling distance and equipment needs. On top of this, the schedule has to continually consider specifications for Fe and the contaminants. Plant yields also have to be kept within a certain bandwidth. Xpac is used to simulate the above parameters, as well as generate the raw data required to produce a mine budget. The paper will also show how the 18-month planning process and subsequent planning processes are measured and aligned. Xpac has proved to be an excellent tool to achieve these goals.

Jan 1, 2005

By T Nassis, P Louw, M R. Fry, T du Toit

Business intelligence (BI) and business analytics (BA) are established IT technologies that are used extensively in the business environment. This paper discusses the use of these technologies in production environments and beneficiation plants.Assmang’s Khumani mine is an iron ore operation located in the Northern Cape, South Africa. Assmang Limited is jointly owned by African Rainbow Minerals Limited and Assore Limited. This paper presents a case study of a BI solution applied to this plant, which is used by metallurgists, supervisors and all levels of operations and management to extract and analyse data to control and optimise the operation of the plant.The main advantage of adopting an established BI solution is the ease with which production personnel can extract and analyse data. The data is easily presented in familiar spreadsheets and no IT staff or specific training is required to achieve this.The solution adopted at Khumani mine uses a data mart with a multidimensional model (called an online analytical processing (OLAP) cube) acting as the main repository and source of data. The OLAP cube simplifies the access and analysis of plant data.The OLAP cube stores data in a specifically-designed way, which allows extraction and analysis to be performed quickly. It is designed to hold large amounts of data on a long-term basis, which could be for the life of the plant. It also performs automatic aggregations over many dimensions on a background process.A major benefit in adopting such a BI solution is that it allows common BA methods to be applied. This is due to both the efficient long-term storage of data and the availability of standard BA tools. BA tools are now able to perform data mining, predictive analytics, forecasting and other machine-learning algorithms. This paper presents the possible use of such advanced data analysis methods in a beneficiation plant.CITATION:Fry, M R, Nassis, T, Louw, P and du Toit, T, 2015. The use of common business intelligence and analytics tools in the operation and optimisation of iron ore process plants, in Proceedings Iron Ore 2015, pp 129–138 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By A M. Lechner, V Glenn, M Edraki, D R. Mulligan, C Unger

With more than 50 000 recorded abandoned mines in Australia, effective management strategies are needed to prioritise and manage health, safety, environmental and socio-economic risks and opportunities. This paper reviews international leading practices for abandoned mine management and identifies key issues that need to be addressed in the Australian context. As well as the academic literature, this review draws on a 2008 global legacy site survey and forum in 2008, a Churchill Fellowship study of abandoned mines and the recently released æStrategic Framework for Management of Abandoned Mines in the Minerals IndustryÆ (MCMPR/MCA, 2010).A conceptual model was developed to identify the relationship between key issues affecting the management of abandoned mines in Australia. The conceptual model is then used in the development of a maturity chart which draws on risk management principles to provide leading practice guidance for abandoned mine managers, jurisdictions and stakeholders. The maturity chart approach for risk management has been successfully used elsewhere to evaluate safety, environmental and socio-economic maturity.CITATION:Unger, C, Lechner, A M, Glenn, V, Edraki, M and Mulligan, D R, 2012. Mapping and prioritising rehabilitation of abandoned mines in Australia, in Proceedings Life-of-Mine 2012 , pp 259-266 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By S DeKruijff

The Mount Isa Mines Copper Mine in Mount Isa started producing copper in 1966. The Copper Mine gradually increased production rates to nearly six million tonnes per year. Over the last three years the mine has been in a gradual ramp down due to the reduction of primary ore sources and head grade. The majority of ore sources are predominantly in pillar retreat sequences bounded by multiple fill masses. There also a substantial lower grade resource delineated to the south of the main orebody. These remaining ore sources present significant engineering challenges to obtain a safe and cost-effective extraction. Stope designs have become increasingly complex and require additional engineering and operations input and analysis. This paper describes the major planning and operational challenges and issues associated with the stope design and extraction of an orebody in the later stages of mine life.

Jan 1, 2000

By M Singh, R C. Steinhaus, J J. Rust

Metallurgical process control systems in mineral plants often employ state-of-the-art monitoring analysers in an attempt to optimise plant operations and enhance mineral recoveries. These systems are unfortunately invariably fed by simplistic ‘sampling’ designs consisting of various in-stream methods or pressurised probes. These are unfortunate compromises and provide a false picture of what a mineral flotation or other process can achieve. The situation is further aggravated by some manufacturers using misleading marketing to suggest discrete cross-stream methods for metallurgical accounting and unreliable continuous in-stream off-takes for control sampling and that they are of synonymous integrity.Reliable, absolute or representative samples are often absent in many modern day concentrator plants, due to compromises around sample taking, particularly in terms of delineation and extraction errors and thus leading to sample bias. For more reliable information from online analysers we need a continuous, but much more reliable sample taken, than is current practice.Online analysers require a fully proportional and continuous supply of sample for effective process control, otherwise maximised or benchmark recoveries will be nothing but a pipe dream. Large discrete cross-stream samples from mechanically less reliable equipment cannot be used as feed to online analysers, as it will negatively impact real-time feedback and efficient process control.It is possible to build correct sampling systems that could do both process controls online and metallurgical accounting at the same time. Multotec Process Equipment (Pty) Limited, in close association with experienced sampling consultant Francis Pitard, have jointly patented a concept to achieve this and which is embodied in the design of the unique Rotating Cone® Sampler (International Patent Application No. PCT/IB2016/057464). This versatile unit for dry and wet applications has high division ratios via two-step sampling and division.A prototype was built and tested to validate the design and levels of precision achievable when employing the unit to split dry mineral fines or even certain foodstuffs.CITATION:Steinhaus, R C, Rust, J J and Singh, M, 2017. Does process control sampling always have to be a compromise?, in Proceedings Eighth World Conference on Sampling and Blending , pp 197–202 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017