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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 H F. Galbiatti, G J. I dos Santos, A de C Zapparoli

The Grao Para and Rio Maria greenstone banded iron formations (BIFs), within the Carajas mineral province, exhibit distinct lithological and petrographic fabrics, together with pronounced differences in their surface expression, real thickness, iron grade and tonnage. These geological differences support a new model for the regional distribution of iron formations in the Carajas Mineral Province.

Jan 1, 2009

By K J. Lownie, T Rafferty

The in situ testing of mine ventilation fan systems has been a contentious issue for many years. Site testing was generally undertaken by adapting standards that were developed for the laboratory testing of fans using standardised airways. The deficiencies inherent in this practice have been widely recognised by informed practitioners, and this led to the first stand-alone document specifically intended for the in situ testing of large fans (ISO 5802:2001 Industrial fans - Performance testing in situ).This paper describes the structure of the International Standards organisation and the processes that are followed in the course of preparing such a standard.The application of ISO 5802:2001 is briefly outlined together with how test data is assessed for compliance with the suppliers guarantee. This paper must be read in conjunction with ISO 5801:2007, ISO 5802:2001 and ISO 13348:2007.CITATION:Lownie, K J and Rafferty, T, 2013. A review of ISO 5802:2001 industrial fans - performance testing i n situ, in Proceedings The Australian Mine Ventilation Conference , pp 149-154 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

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 A L. Wills

Cliffs Natural Resources Pty Ltd (Cliffs) operates iron ore mines in the Koolyanobbing region of Western Australia. Ore is mined from three separate hubs and trucked to Koolyanobbing. There it is crushed and screened to lump and fines finished products and railed to Esperance port for export to Asian customers. Cliffs is renowned in the marketplace for its consistent product quality. In 2010, 9 Mt of ore was exported to Asia.Over the last three years, Cliffs has systematically refurbished its product quality system (PQS), to improve efficiency of production while maintaining its high standard of product quality. Particular attention has been given to reducing inventory, which has required significant modifications to the production process design.In redesigning the production process, emphasis was placed on maximising the application of the inherent blending in each of the production process steps and dedicated blending was only introduced where essential. Simulation modelling and statistical analysis of process capabilities were utilised to develop a system that optimises inventory, minimises rehandle, eliminates several decision-making steps and maintains a pull focus throughout the value chain.The new planning functions are now fully integrated and effectively control long-term grade variability rather than relying on long-term stockpiling. The production process design and the daily crusher blend plan are used to control short-term grade variability. With the upgrading of the planning processes the accuracy and consistency of algorithms for lump per cent and lump and fi nes grades became more important and an increased geometallurgical function has been added to the company.The continuous stockpile management system was upgraded to increase the effectiveness of the daily crusher blend planning process and is now the sole intervention point in the production process for grade-based decisions. Grade control systems were modified to utilise advances in software and geostatistics to deliver accurate short range planning models. The reconciliation and sampling systems have also been refurbished with an emphasis on practical application and feedback loops.Accountability and transparency are provided by management reports that are generated from a centralised data warehouse and the introduction of a corrective action system. Standardised reports are available to all stakeholders and a quarterly KPI scorecard assists the management review process.The successful rejuvenation of the PQS has culminated in operational efficiency through the implementation of an integrated end-to-end process flow. Shareholder value is maximised through maximising recovery of the resource and minimising costs. Customer focus is maintained by reliably delivering product with acceptable and low grade variability.

Jul 11, 2011

By T M. Nester, D J. Reardon, A N. Page, B J. Barsanti

The load capacity of a friction bolt has long been regarded as 4 t/m of embedment for ground support design analysis and supported by in situ pull test results. In recent years, the authors have observed lower pull test results or inconsistent results which were rarely sighted in the early 2000s. The lower pull test results indicated in some cases that reliable friction bolt capacity (≥90 per cent of results) is closer to 3 t/m of embedment with some geotechnical engineers adjusting the ground support parameters in the design work accordingly. This can be in contrast with other mines which reliably obtain 4 t/m (or greater) using the same suppliers bolt in similar ground conditions. This raised several questions: • What is the effect of poor installation (bolt twist or bolt hole deviation)? • Does the performance of friction bolts vary in different rock masses? • Does bolt performance vary between suppliers? • What effect does increased jumbo feed/percussion/rotation settings have? • Have the bolt dimensions or steel strip width changed? • Have the physical bolt properties changed? • Have the steel properties changed? This paper was aimed to answer as many of these questions as possible and discuss each variable in detail. This project included friction bolt trials at various mine sites across Australia, multiple friction bolt manufacturers, steel manufacturers and laboratory analysis. The paper also includes discussion on what the authors consider best practice for pull testing. It should be noted, the terms ‘friction stabiliser’ and ‘split set’ used in this paper are used in a generic manner and is not linked to any specific ground support supplier. Whilst its acknowledged within the industry the term split set and friction stabiliser is used interchangeably, the authors acknowledge that the term split set is a trademark of Split Set Mining Systems and has been used in context in this paper.

Nov 29, 2022

By M Hopkins, A Mutale, A E. Vidal da Silva

The Cliffs Nickel Mine extracts a narrow near vertical nickel vein using a mining method of underhand bench stoping with paste backfill. In 2014, at a depth of 400 m below surface, the Northern block of the mine began to experience squeezing within ore development. At first the deformation was localised, within 30 m of the stoping front, but later became pervasive extending across the Northern block and resulting in a hiatus in mine production. The global mechanism is a progressive pillar failure, where the inter-level pillars in advance of the production front could no longer withstand the induced load and progressively yielded. The local mechanism of failure was observed as crushing of the massive sulphide ore and ‘punching’ of the pillars into the ultramafic hangingwall exhibited as floor and sidewall dilation and unravelling of the mafic footwall. The cause of the global mechanism was attributed to a combination of factors, including: high overall extraction ratio, small vertical pillar heights between ore development, high stress in relation to the low rock mass strength, shallow stope front angle, and insufficient ground support capacity. Following the progressive failure, the remnant rock mass conditions across the northern block were severely degraded, with numerous falls of ground that led to a reassessment of the mine plan. Recovery of the Northern block started in 2016 as a staged process. Development of the safe recovery work methodology involved a number of considerations, such as: production sequencing, development access design, ground support, and development of specific procedural controls. The Northern block was then broken into smaller mining precincts based on tactical factors such as location, ease of access, scale of rock mass damage and nickel content. A specific ground support standard and work methodology are employed, while cycle sheets are used to ensure quality and completeness of work. Large intersections showing signs of deformation have either been bypassed or treated using Rocprops to maintain stability during stope production. This approach has been successful in safely regaining access and restarting production in areas that had previously been removed from the mining reserve.

Mar 15, 2021

By R Bose, M Bovell, G Cheong

Grinding media is a major consumable in mineral processing and therefore decreasing costs associated with its consumption is regularly considered a key goal for the minerals processing industry. Grinding media manufacturers have historically developed steels with improved wear life for their products as a way of delivering incremental media quality improvement. This has included increasing carbon levels from low-to-medium carbon steels up to the eutectoid carbon composition of 0.77% where the relationship between higher carbon and better wear performance is well understood. Producers today will regularly use grades in excess of 0.8% to further improve wear performance particularly for rolled grinding media.This paper first introduces the demonstrated relationship between this increased carbon content and improved wear resistance along with metallurgical rationale behind the high carbon production process and limitations. To test the performance improvement associated with the higher carbon steel grade, a series of Marked Ball Wear Tests (MBWT) were carried out. This paper also explores the relationship between ball properties, test methodology and wear performance and concludes by correlating increased carbon grade with a reduced consumption rate of between 3.1% and 6.1% in the tests conducted.CITATION:Bovell, M, Bose, R and Cheong, G, 2018. Improved forged grinding media performance with carbon content greater than 1.0%, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 559–570 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By D Hillier, A Giblett, K Parker, V Ramsell

Kalgoorlie Consolidation Gold Mines (KCGM) operates the Kalgoorlie Super Pit open cut, Mt Charlotte underground mine, Fimiston process plant and Gidji Roaster facility for joint venture partners Newmont Mining Corporation and Barrick Gold. In 2004, the Fimiston plant was upgraded by the addition of gravity concentration to the Fimiston and Mt Charlotte grinding circuits, including the installation of a central intensive cyanidation reactor to process the gravity concentrates. The gravity project was justified after detailed analysis demonstrating an expected increase in overall gold recovery of approximately one per cent, in addition to reduced elution costs and reduced gold inventory in flotation concentrate stockpiles. The gravity circuits were commissioned in August 2004, and have since consistently recovered 10 to 20 per cent of the gold present in the KCGM ore, delivering a reduction in coarse gold losses equivalent to 0.45 per cent additional metal recovery and contributing to improved metal accountability.CITATION:Giblett, A, Hillier, D, Parker, K and Ramsell, V, 2012. The impact of gravity gold recovery at Kalgoorlie Consolidated Gold Mines, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 199-206 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

Societal expectations about how the industry operates and treats its people will be a key driver in the development of the Australian mining industry over the next 20 - 30 years (Moffat, Mason and Littleboy, 2009). Understanding these expectations will be critical in maintaining what much of the minerals industry calls its 'social licence to operate', or its public acceptance or approval. Yet what constitutes this social licence is poorly articulated, with little published research exploring the concept at a local operational level or at the national level in Australia or internationally. This research aimed to explore the societal expectations of the mining industry in Australia and test a participatory methodology to articulate them. Three workshops were conducted with a sample of 24 members of the 'Australian voting public' to explore community objectives for the onshore exploration and mining industry, and the underlying expectations for how the industry should operate in the future. Qualitative analysis of this data revealed three overarching objectives for the onshore mining industry held by participants. They thought that the industry should: advance Australia's national interests (including social well-being); minimise environmental impact, and; act in a socially responsible manner. Within each of these three key themes, or objectives, a number of tensions were evident in the views of participants regarding the trade-offs they are willing to make to secure economic benefit from mining, as well as the basic conditions for socially acceptable mining. These data provide an insight into the conditions for a national social licence in Australia for the mining industry, and the means for its realisation.

Jun 1, 2010

By D Hunter, N Cusworth, J Miller

"Recent project failures have called into question the use and relevance of benchmarking and independent reviews, forcing a rethink of traditional processes and procedures.With cost estimates and schedules dramatically varying from lows seen around the global financial crisis to peaks experienced in the recent mining boom, benchmarking has ranged between essential and misleading.Profound shifts are now underway in future project delivery strategies as the market moves away from cost-plus engineering, procurement and construction management. The current trends in project implementation are to utilise more lump-sum design and construct or fixed-price supply and construct contracts. This trend will remove transparency in detailed cost information by reducing the sources and clarity of cost data.Independent peer reviews (IPRs) of studies and investment recommendations performed over the last decade have both failed to prevent flawed or deficient projects from proceeding to approval and funding, and been successful in ensuring that owners did not proceed with doomed investments.In recent times, it has been recognised by some owners, contractors and engineers that traditional benchmarking checks or IPRs, or a combination of both, will not necessarily produce reliable assessments of study conclusions and of the forecasts of project outcomes. To be of value, the benchmarking process now also needs to recognise the highly volatile responses from the engineering and construction industry to the current and future markets for their services.Similarly, reviewers who draw upon benchmarks of past project experiences on an understanding of the things that shaped and influenced their outcomes need to be more aware of how a future dynamic market may impact the outcome of the projects and raise warning flags accordingly.With the commodity cycle currently approaching what is hoped is its bottom, ensuring that benchmarking and independent reviews evolve into reliable, transparent and worthwhile processes becomes even more important. This can only be achieved with more transparent and analytical benchmarking and business-orientated reviews that both recognise and calculate the impacts of dynamic markets on project implementation.CITATION:Cusworth, N, Hunter, D and Miller, J, 2016. The role of benchmarking and independent reviews, in Proceedings Project Evaluation 2016, pp 249–259 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 8, 2016

By B J. Beven, A Vatandoost, J Young, S Campbell-Hardwick

The intrinsic value of iron ore depends on its physical and chemical characteristics. For example, silica and alumina are unwanted elements, downgrading iron grade and adversely affecting high temperature processing, attracting penalties in smelter contracts. For this reason, an informed knowledge of processing characteristics and product quality of the ore is valuable and cost effective during mine planning and processing.Ore variability is a significant factor that affects metallurgical behaviour and efficiency of ore processing equipment. Ore of sufficient chemical and physical quality needs to be modelled, mined, processed and usually blended. Feed and product assays are commonly used to assess potential ore upgradability. However, assays alone cannot be all informative of actual processing response given the variability of the physical properties of the ore.This study investigates the potential benefit of implementing a geometallurgical approach during the commissioning stage of the Kings deposit, part of the Solomon Iron Ore project in Western Australia. Kings drill hole database information, ie geological, textural and geochemical data, together with the results of metallurgical test work were used for geometallurgical analysis and modelling. Three main ore types were identified at Kings, namely channel iron deposit (CID), bedded iron deposits (BID) and Detrital Iron Deposit (DID). Additional classifications were utilised to better characterise these units in terms of their physical properties.Bulk sampling for each ore type was carried out across the deposit for metallurgical testing. Multivariate statistical models were developed for prediction of product quality for each geometallurgical unit. A new approach for modelling yield based on ore upgrade factors is introduced. These models were then applied to the Kings regularised mining model to assess product quality across the mining blocks and to plan product stockpiling and blending strategies.CITATION:Vatandoost, A, Beven, B J, Campbell-Hardwick, S and Young, J, 2013. A geometallurgical approach for iron ore product evaluation, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 259-266 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

By E Ruhanen, S Kauvosaari, M Kosonen, C Meintjes

The Yara Siilinjärvi plant is located in the central part of Finland. Siilinjärvi is Western Europe's only apatite mine and annually it produces 1 Mt of apatite concentrate, which creates approximately 10 Mt of tailings.At the beginning of 2017, tailings handling in Yara Siilinjärvi was brought to a new era, by replacing the conventional tailings storage facility with a new tailings treatment plant. The new high-density tailings disposal system with two paste thickeners increased the percentage of solids in the slurry from 45–48 per cent to 66-68 per cent, making it possible to deposit as a paste. This extended the life-span of the current tailings storage facility by 15 years; from 2020 to 2035.This paper presents the storyline of the Yara Paste Plant Project. The project began with laboratory testing and then progressed to pilot-scale thickening and beaching trials. After some successful pilot trials, the final process design was implemented. Process instrumentation and automation played a key role in the project, as the aim of the Yara Project was to make the plant operable remotely from the main plant. An advanced control system is needed to maintain process stability and the desired operation point in various operational circumstances.This paper discusses the results from the Yara site since the new tailings treatment plant commenced. Some of the main points are that the operation has been running consistently with an underflow solids content of 66-68 per cent, with average beach slope angles of 3.5 degrees in the tailings disposal area. This control system additionally facilitates minimum use of flocculant, which delivers significant savings to operating costs. Robust thickener operation also leads to the trouble-free high-density pumping and high availability of the Paste Plant. During the first year of operation, the plant’s availability has been very good, over 97 per cent.Currently, the plant still has its own staff working there during the daytime, but the Paste Plant is now already operated remotely during the night shifts. The long-term goal is to gradually transition into operating the plant completely remotely.CITATION:Ruhanen, E, Kosonen, M, Kauvosaari, S and Meintjes, C, 2018. Optimising the operation of paste thickening at the Yara Siilinjärvi Plant, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 297–310 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By P Clark

This paper discusses the challenges, solutions and lessons learnt as tunnelling work continues on the Melbourne Main Sewer Replacement (MMSR) project.The MMSR project is a $220 million dollar project for the Melbourne Water Corporation. It involves the construction of approximately 4.2 km of new sewer from the southern fringe of the CBD through the inner metropolitan suburbs of Port Melbourne and South Melbourne.Of the 4.2 km of sewer currently in construction approximately 2.2 km will be constructed using a 2.95 m diameter Lovat EPB tunnel boring machine (TBM) with approximately 1.9 km of small diameter (300 to 600 mm) reticulation sewers constructed using trenchless techniques.These sewers are being constructed in a dense urban environment, which means that the tunnels and shafts are often in close proximity to buildings and structures. The underground constructionof the sewer is further complicated by the variable geology of the ancient Yarra River delta which includes weathered basalts, the infamous Coode island silt formation and fine loose sands.Some of the key challenges and lessons learnt so far during construction include:· steering and alignment control of the TBM through very soft silt with little residual strength,· development and refinement of a monitoring and alarm system for leaving the machine dormant on a day works only project,· control and measurement of tunnel lining defl ection during ring build and grouting,· prediction and monitoring of surface settlements during tunnel excavation,· improved understanding of the geology and hydrogeology at this previously unchartered area of Melbourne,· consolidation settlement due to dewatering at shafts required careful construction controls, and· ground support and excavation in close proximity to the existing 110 year old sewer which requiredvery detailed risk control measures.

Mar 8, 2011

By H Khoshrou, A Siamaki

Blast designs can have productive and non-productive impacts on downstream stages, mine productivity and operating costs. On the other hand, ground vibration, fragmentation, and back break caused by blasting impose damage and financial penalties and which must be controlled by blast design. One of the significant variables in blast design is the burden. In this study, the potentials of artificial neural network are investigated in prediction of burden in the Sungun copper open-pit mine. Input data were assembled through 18 blasting blocks according to different levels and experimental geomechanical investigation. To construct the model blastability index, uniaxial compression strength, hole diameter, specific weight of rock, rock quality designation and cohesion strength are taken as input parameters, whereas, burden is considered as an output parameter. Mean square error was used as the performance function and back propagation algorithm as the training function, containing four hidden layers and 14 data sets. Four sets of data were used to make sure that correct training had been carried out. This produced the coefficient correlation of 0.662.

Sep 26, 2011

By A E. C Peres, P R. M Viana

The role of flotation columns in comparison with conventional mechanical flotation cells is discussed under the scenario of Brazilian flotation technology. All iron ore concentrator circuits commissioned since 1990 incorporated column only flotation technology in rougher, cleaner, scavenger configuration. Columns were also added to existing circuits, especially at the cleaner stage. Columns were also incorporated to phosphate ore flotation circuits operating mechanical cells. In two phosphate concentrators, columns substituted for all mechanical cells. Columns perform the cleaning stage in a large sulfide copper concentrator, following rougher flotation in tank cells. Scavenger of the cleaner tailings is performed in tank cells at this plant. Other ores that are concentrated in flotation columns include graphite, talc, lead-zinc sulfide, and a zinc hydrometallurgical residue for silver recovery.

Jan 1, 2005

By S Schwarz, D Alexander

The mining industry, and in fact the world, has undergone significant changes in the past five to ten years, ranging from the metals boom, the global financial crisis and the rise and fall of national economies, to name just a few. There has been a focus on sustainable development for projects and operations in the mining industry, mainly pushed onto the industry by communities, governments and other agencies. While sustainable development and operation is a worthy priority for mining operations, discussions with mining industry personnel (with a strong slant on the mineral processing perspective) have shown other issues have surpassed the typical issues of water resources, energy availability and the environment. These include staff turnover and skills shortages, extracting metal from more complex orebodies and the uptake of new step-change technology.A number of key operating mineral processing personnel were interviewed to determine their perspective on the current issues facing the mining industry. This paper details the findings of this survey and highlights some of the topics that have been identified as the top issues from a mineral processing perspective.CITATION:Schwarz, S and Alexander, D, 2012. Current issues in the mining industry - From the operational mineral processorÆs perspective, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 369-372 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By C E. Woolley, H Jebaliya, J Foster

The East wall of the Kalgoorlie Consolidated Gold Mines Fimiston Open Pit (KCGM Superpit) has a history of wall instabilities impacting mining operations; the most significant of which occurred in May 2018, when more than 1 Mt of rock dislodged over six, 30 m high bench stacks and impacted the pit floor. Since 2011 approximately 1.250 Mt of material has fallen from the East wall at Fimiston Pit across three failure events (2011, 2018 and 2020). Each failure has been associated with major structures intersecting the pit walls: the Fiji Fault, the Australia East Secondary Splay Fault and the EWD3 Fault. In each instance the trigger for failure has been transient pore pressure in the pit walls. Northern Star will mine a cut back behind the failure area over a vertical distance of 180 m. Cut back mining will include the extraction of a remaining in situ wedge, which is assessed as kinematically able to fail, and a subvertical failure backscarp in Stage 1. A substantial amount of rill material from the 2018 and 2020 failures will be extracted in Stage 2. This paper presents the methodology in use to mine Stage 1 of the cut back, safely, through this potentially high-risk area, detailing the specific mining methodology employed, the controls put in place and the monitoring required. Day-to-day monitoring will be undertaken using the already installed slope stability radar and will feed into a daily assessment of activities which may be undertaken in the cut back area. Initial activities will focus on eliminating the potentially unstable wedge and vertical backscarp with use of innovative drill and blast techniques/products and the extensive use of remote capable equipment to limit personnel exposure.

Jun 22, 2022

By M Szwec, P Corbett, P Sheffield

Centennial Coal operates the Springvale and Angus Place longwall mining operations that extract coal beneath the Newnes Plateau in the Western Coalfields of New South Wales. Springvale and Angus Place mines have a history of difficult geotechnical conditions, where mining operations are conducted with a thick coal roof interbedded with numerous claystone units and relatively high levels of vertical and horizontal stress. The combination of a relatively high stress regime and weak laminated roof has led to numerous roof failures throughout the mine’s life.Following underground roadway development, the mine roadways can experience high levels of roof movement that can lead to roof falls. Two-point wire extensometers (known as ‘telltales’) are extensively used for roadway condition monitoring. Along with extensive other geological and geotechnical data, monitoring data is used to prepare geotechnical hazard plans that are then used in all areas of mine planning to allow for safe and efficient operation of the mine.This paper presents a case study of the use of a new software tool that allows time-scaled visualisation of monitoring data in the context of longwall and development face positions and installed strata support. It can be used in the identification of geotechnical risk factors and their interaction with the mining process to allow a more robust geotechnical hazard process. It interfaces directly with the widely used ExtoChart database software and can be presented with scale drawings of geological/geotechnical data to allow correlation of monitoring data with risk factors.CITATION:Corbett, P, Sheffield, P and Szwec, M, 2014. A new tool for extensometer data analysis and improved understanding of geotechnical risk factors, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 217–232 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By D Kentwell

IGO Ltd’s (IGO) Nova Operation (Nova) is 160 km east-north-east of the town of Norseman in Western Australia (WA). Discovered by Sirius Resources NL (Sirius) in 2012 and acquired by IGO in 2015, the Nova-Bollinger Deposit (Nova-Bollinger) occurs within the Fraser Zone of the AlbanyFraser Orogen. Nova-Bollinger is a complex nickel-copper-cobalt (Ni-Cu-Co) magmatic intrusive sulfide deposit, which is characterised by high-grade folded and undulating breccia lodes that host the bulk of the payable metals. Significant sulfide mineralisation is also found in several magmatic intrusive styles including net-textured, disseminated and blebby styles. A smaller but material volume of sulfides has also been remobilised into the deposit’s footwall rocks as ‘stringer’ bands in metasediments, or as discrete massive sulfide lenses. When interpolating Mineral Resource estimate (MRE) block grades in the presence of locally varying grade connectivity trends, such as folds or undulations, the sample search neighbourhood, which is used to identify the composites subset that is used for each block estimate, should be oriented to match the local trends. In theory, the most robust method of estimation where locally varying angles (LVAs) are applied to search neighbourhoods, are techniques where the composites and the blocks to be estimated are transformed to an unfolded coordinate system (UCS). However, UCS methods can be tedious to implement and require subjective decisions to be made that cannot always be fully defended. An alternative LVA method commonly used in the industry is dynamic anisotropy (DA), which is much simpler to implement and is often assumed (but not that often demonstrated) to result in similar results to UCS-style estimation. In 2018, Nova’s Mine Geology team (MGT) estimated the grades and density of the Nova-Bollinger MRE using the UCS approach. For the 2020 MRE update, Nova’s MGT tested and compared the USC grade interpolation method with the DA approach. As applied to the Nova-Bollinger’s 2020 MRE, the comparison, advantages and disadvantages of the two estimation methods are the subject of this paper

Mar 22, 2022