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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 A K. B Chigwada

Mining organisations grapple with the same problems year after year, wasting incredible amounts of time and money. According to estimates from the International Labour Organization (ILO), over one million work-related deaths occur annually, and hundreds of millions of workers suffer from workplace accidents and occupational exposure to hazardous substances worldwide. Many accident reports cite human failure as a primary cause (Busse and Johnson, 1998). The workers at the Bhopal chemical plant pumped methyl isocyanate into a leaking tank (Morehouse and Subramaniam, 1986). On 3 December 1984, more than 40 tons of methyl isocyanate gas leaked from a pesticide plant in Bhopal, India, immediately killing at least 3800 people and causing significant morbidity and premature death for many thousands more. The company involved in what became the worst industrial accident in history immediately tried to dissociate itself from legal responsibility (Broughton, 2005). Australia is not spared from safety problems either (Lucas, 2022). The ILO Convention 176 (1995) as a response provides that national law should inter alia provide for the supervision of safety and health in mines; the inspection of mines by designated inspectors of the competent authority; the procedures for reporting and investigating of fatal and serious accidents; the compilation and publication of statistics on accidents, occupational diseases and dangerous occurrences; the competent authority to suspend or restrict mining activities on safety and health grounds until conditions giving rise to the suspension are addressed; and worker consultation on matters related to safety and health in mines. This has assisted in getting enough data to define the magnitude of the problem to the mining sector.

Apr 16, 2024

By K J. Riihioja, E Nozawa

SmartTag is a radio frequency identification (RFID) based technology designed to allow tracking of ore from its source through blasting, run-of-mine (ROM) pads, crushers, intermediate stockpiles and finally into the concentrator. This paper presents current developments and the future direction of the SmartTagÖ ore tracking system, as well as presenting some case studies. Successful applications of the SmartTag system have encouraged development to allow the system to be used in a wider variety of plants, in particular plants with finer crushing and screening stages. This presented Metso with a number of technological challenges, including RFID tag and antenna design. By reducing the traditional RFID tag diameter from 60 mm to 20 mm the RFID tags can now successfully pass through a secondary crusher. The new smaller RFID tags (referred to as mini RFID tags) have been used in some Process Integration and Optimisation projects with very promising results. The results indicate that the miniature RFID tags have a higher survivability to blasting and through secondary crushing stages. Extending ore tracking further through the process allows more reliable linking of spatial data with time based process performance. Metso is looking at developing even smaller micro RFID tags, and is also investigating other applications for the SmartTag system, including ore tracking from the original source to the final destination (ie from the mine, through the plant and ports to the customer).

Sep 26, 2011

By C B. Smith, G L. Boxer, S W. Moss, A L. Jaques, V Lorenz, M J. Rayner

The Ernest Henry Iron Oxide Copper Gold deposit is hosted in a large dilation between two moderately dipping shear zones found in the footwall and hanging wall of the deposit. These shears are controlled by a large diorite intrusion to the north-east and south-west of the deposit, formed ~1660 Ma. A shear zone dubbed the ‘Interlens’ uncovered through underground workings truncates the main orebody into two lenses, and is hypothesized to have formed in conjunction with the Hanging Wall Shear Zone and Footwall Shear Zone. All three shears dip moderately to the SSE (50–140) from open cut exposures through to the current mining horizon approximately 800 m below the surface. Routine geological work and a capital drilling campaign has identified a significant flexure in these sub parallel ore bounding shears with increasing depth. A shift in shear orientation in the Interlens over approximately 100 m vertically from ~50° to the SSE to a steep, easterly trend (~85° to the east) is observed in both drill core and exposures in the underground workings. It is hypothesized the diorite intrusive to the south-west of the deposit controls the shear zone geometries at depth. The geometry of the Interlens mirrors the surface expression of the Proterozoic package of the orebounding shears to the south-west of the deposit, suggesting the surface geometries of the shear zones are consistent with depth. Additional drilling to explore the validity of this hypothesis is planned for the near future to better understand the structural controls on the Ernest Henry mineralisation with increasing depth.

Mar 22, 2022

By J Tibbett, A Colebourn, B Hebblewhite, F Suorineni

The concept of Big Data refers to data sets that are so large, variable and/or complex that traditional data processing applications struggle to integrate the data for effective investigation, analysis and value generation. With advances in sensor technology and smarter equipment, the mining industry is experiencing Big Data, and in a different way to how the intelligence and marketing communities experience Big Data. Future mining will bring larger, more complicated and diverse data sets increasing the strain on traditional data integration and investigation techniques. Block caving is an important mining method for the extraction of massive, low-grade ore deposits due to its low operating cost and high production potential, given the right orebody geometry and ground conditions. This paper focuses on block caving due to its increasing popularity and importance in the future economic extraction of multiple commodities. The block cave mining system (BCMS) is a complex interrelation of factors, and due to the reliance on natural processes within the system, it is one of the least understood mining methods. Obtaining information on the factors within the BCMS generates large, complex data sets on various time scales. Each sensor network within the BCMS combines spatial and temporal information with tens to hundreds of recorded parameters. Data sets are quickly moving from multidimensional to n-dimensional. Optimisation of the BCMS is only possible through a holistic analysis approach, thus involving the integration of multiple, diverse, n-dimensional data sets (Big Data). This paper presents a current example BCMS Big Data situation involving 12 sources of information with differences in volume, data format and frequency of data generation. This suitability of virtual reality scientific visualisation (VRSV) as a solution to BCMS Big Data interpretation difficulties is then discussed. These 12 data sets can be effectively integrated using VRSV for intuitive and accelerated investigation of the BCMS. Potential future Big Data within the BCMS is presented involving 20 sources of information resulting from our increased need for monitoring and advancements in technology. Current methods of defining queries may not be suitable within these future complex, multidimensional data sets, and the potential of artificial intelligence algorithms within this system is discussed. These advancements in technology and machine learning lead to the requirement of live data acquisition and analysis. VRSV is identified as a suitable technology to satisfy the needs of real-time insight into the performance of these future caves for optimised management and reduced risk.CITATION:Tibbett, J, Suorineni, F, Hebblewhite, B and Colebourn, A, 2015. Virtual reality scientific visualisation – a solution for big data analysis of the block cave mining system, in Proceedings Third International Future Mining Conference, pp 109–116 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

By J Jeffery, P G. Knott, F Velge, C Evans

A trigger action response plan (TARP) provides a structured response to escalating levels of risk. In mining, TARPs are typically applied to primary hazards such as inrush, strata failure or heating. Necessary for the creation and deployment of a TARP is a monitoring system capable of detecting deviations from normal conditions. The advent of real-time instruments capable of measuring diesel particulate matter now permit decision-making within shifts to address possible overexposure. Deploying a TARP for diesel exhaust emissions can lower the probability of a person’s average exposure (over a full shift) exceeding the exposure standard by detecting deviations of diesel particulate concentrations from normal conditions. This enables pre-emptive action to mitigate or protect. Another goal is to drive ambient air concentrations lower through the application of corrective actions as a result of instances where concentrations exceed ‘normal’.CITATION:Knott, P G, Evans, C, Velge, F and Jeffery, J, 2015. Trigger action response plans for diesel exhaust exposures, in Proceedings The Australian Mine Ventilation Conference, pp 129–132 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By T Wambeke, J Benndorf

A risk-robust development of a heavy mineral resource requires an assessment of the geological uncertainty and spatial variability of the key factors impacting the mining and processing operation. Attributes of interest are the total heavy mineral grade, the slime content and the amount of oversized particles. The modelling of a mineral sand deposit presents two main challenges. Firstly, the exact location of the geological boundaries are obscure due to the complex interaction of the deposit formation processes. Secondly, the properties of interest exhibit a rather complex transitional behaviour across the so-called soft boundaries. Traditionally, the modelling exercise is restricted to a consecutive stochastic simulation of distinct geological facies and orebody properties. This results in different zones separated by hard boundaries, ignoring the typical transitional behaviour.This contribution presents an alternative approach which models the entire sand body as a single domain while accounting for the complex trends present. Error curves are used to infer covariance model parameters without the need of a prior removal of the trend. The principle is based on minimising the differences between empirical and theoretical errors resulting from two methods of prediction calculated for different rings of influence. The added value results from the unambiguous decomposition of the spatial variation into a deterministic trend and a stochastic residual. The trend model neither overfits nor underfits the data. The calculated residuals are thus unbiased and the uncertainty can be correctly assessed.The effort results in a characterisation of the resource uncertainty which provides a more realistic image of the spatial variability of the key properties in and across the geological domains of an existing heavy mineral sand deposit.CITATION:Wambeke, T and Benndorf, J, 2014. Optimal inference of modelling parameters to simulate complex trends across soft boundaries – a case study in heavy mineral sands, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 73–84 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By D Bruce

OZ Minerals’ Carrapateena mine is a Sublevel cave mine located in South Australia, approximately 160 km north of the regional centre of Port Augusta. Carrapateena commenced underground development in 2016, with production commencing in 2019 and ramping up to 4.25 Mtpa by December 2020. In pursuit of continual improvement, the Carrapateena mining team sought to identify how it could better interrogate its current productivity levels and its drivers (root causes). During this process the team were confronted by a disconcerting number of different opinions (which often conflicted) on our actual productivity performance which led to a need for review. Although reliable data and a well-designed time utilisation model (TUM) existed, it was still unclear what actions needed to be put in place to improve productivity. This was for the following reasons: • Data sources were disparate unless significant effort was applied to compile them. • Data sources were not available in a format that could be easily viewed or analysed. • General understanding of the data which was collected and how it could be used was poor. • Process of regularly analysing performance and forming tangible actions to improve was lacking rigour. A project was then started with the goal to fix the areas stated above. An initial requirements gathering exercise was undertaken to identify key data sources for site which returned a staggering 42 known systems which were then shortlisted to the key systems that contained operational data and could generate tangible improvements when analysed. This paper discusses the approach to selecting the OZ Minerals Insights Hub as the chosen platform, and the effort and collaboration between cross-functional departments that was involved in transforming the data so it could be displayed in a useful way. The data sources identified included a fleet management system, two planning databases, a control system historian, and a mobile fleet machine data system. New processes were also introduced to digitally capture daily commentary; this was achieved utilising SharePoint Forms. Data pipelines were then developed in the Insights Hub platform to automate the ingestion and transformation of the raw mining data into curated data models for end user consumption. Tableau dashboard packages have been created to support facilitation of short interval control, daily review meetings, and weekly review meetings as well as data analysis of key equipment and locations. These dashboards visualise the mining data models in a form that provides the user a clear picture of what has occurred, why it has occurred, and where to focus improvement efforts. This has resulted in a team which is more accountable, more equipped to assess the root cause of performance, and more regularly able to make data driven decisions. The next step? To build this out from Mine to Mill and create a data indexing tool which will drive self-service reporting, a data agnostic platform and predictive tools that help our people continue to be one step in front.

Mar 29, 2023

By J P. van Dyk

A new crude ilmenite beneficiation process was recently proposed that allowed for the preparation of a smelter grade ilmenite from ilmenite with elevated chromium content. Magnetising roasting was not utilised in the process. As part of this circuit an ilmenite low susceptible reject stream was produced that had a low magnetic susceptibility. In this article a magnetising roasting process was investigated to beneficiate this material. Tests were conducted on material produced by pilot scale simulations on a typical South African East Coast heavy mineral reserve. The results obtained were compared to those published in literature for crude ilmenite. The small-scale experiments were used to define approximate operational limits for the oxidising roasting of a low susceptible ilmenite low susceptible reject stream, although industrial roasting conditions may differ significantly from those obtained in laboratory units. In a next phase these results will be confirmed on pilot plant scale.

Jan 1, 2001

By L Drowley

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

Mar 8, 2011

By M Kent, D Elder, J Woodward, R Edwards, B Catto

At Tropicana gold mine (TGM), mine planning is completed from ‘one source of truth’ known as the Integrated Planning Model (IPM). The IPM is a block model which forms a core component of the TGM Mine Planning System – used for short, medium and long-term mine planning cycles, and for Mine to Mill reconciliation.The IPM was developed from a desire to consolidate long-term information contained in mineral resource and ore reserve models, with short-term information from the grade control processes, including grade control models and ore polygons.The IPM is informed initially by resource models, upon which the longer term budget and schedules are based. The IPM is routinely updated with grade control models and ore design information, providing increased confidence for short to medium term mine planning. In this format, the IPM also provides a framework for reconciliation of resource performance with grade control, mining actuals and mining schedules, and ultimately milling. As well as a means for analysing past performance through reconciliation, it has proven its worth as a predictor of variation and an input to successful schedule sequencing and change management. The IPM is a critical component of the TGM Mine Planning System, providing a centralised framework for short interval mill feed prediction through to life-of-mine (LOM) planning.Current development of the IPM is working towards incorporating Mine to Mill optimisation and real-time material tracking projects at TGM. If successful, the model will provide a truly powerful mine planning data source. Current development outlines a mechanism for tracking material from Mine to Mill, and for transferring mill performance data back to the IPM. Increasingly advanced material classification and mine planning, incorporating the multiple geometallurgical variables, will enable the mine to provide consistent mill feed products and result in a steady state and optimised mill.This paper outlines the vision, creation and benefits of the IPM at TGM. It also introduces the ongoing developments to ensure the IPM becomes only more relevant to successful and integrated mine planning as TGM matures from the new kid on the block to the old hand in the neighbourhood.CITATION:Catto, B, Elder, D, Edwards, R, Kent, M and Woodward, J, 2017. An integrated approach to mine planning – building the integrated planning model at Tropicana gold mine, in Proceedings Tenth International Mining Geology Conference 2017, pp 305–314 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By J Heyes, R Getty, M Sanapala

Closure is an inevitable part of the life cycle of every mine. Successful closure outcomes critically depend upon early and ongoing integration of closure planning and mine planning. Early and holistic integration minimises residual risk and maximises opportunity to leave a cost-effective, positive legacy for the company, investors and future land users. Both disciplines are inherently interconnected and aim to maximise ‘value’ via trade-offs. Historically, integration of closure into mine plans has been poorly implemented across the industry. There is still a perception that closure planning only starts as the end of a mine life approaches. This inevitably leads to tension when making business decisions, with progressive closure often being deferred due to short-term drivers and incentives. To create a positive legacy after production has ceased, this tension can be managed by transparently and fully informing business decision-makers, such that the impacts of short-term decisions on long-term closure objectives are understood. BHP recently updated a business-wide standard ‘Our Requirements for Closure and Legacy Management’ designed to strengthen collaboration, education and integration of closure across the entire life cycle of the asset. Concurrently, the ‘Life of Asset’ definition was refined to include the postproduction phase, until closure objectives have been met. This paper discusses the criticality of mine planning integration with closure and how updates to Our Requirements sharpen the focus from transactional to transformational planning. These concepts are applicable to any mining operation aiming to achieve successful closure across the full asset life cycle, from exploration to post-production.

Sep 18, 2023

By T Walton, C Perring, M Pepper, G Gerber

The Yandicoogina Channel Iron Deposit (CID) is an accumulation of iron pisolites cemented by a goethite-rich matrix. The Yandicoogina CID’s are found in a palaeochannel that meanders within a broad structural basin of the Yandicoogina Syncline in Pilbara region of Western Australia. RTIO Yandicoogina Mine Geology team contributed to a number of strategies maximising the iron ore reserves mined by Rio Tinto. Two strategies are discussed: the replacement of the Batter-Berm final pit walls by contour dozing; and upgrading the lower grade material to crusher feed. 1. Contour dozing – traditional Batter-Berm pit final wall configuration left kilometre long wedges of ore sterilised around bench margins. Contour dozing final walls (ie dozing of ore down the ore-waste contact) as internally defined by RTIO Yandicoogina Mine Geology (Mine Geology), enabled recovery of additional crusher feed. 2. Upgrade of lower grade material – the lower ore domain (GVL) within the Yandicoogina orebody contains numerous clay pods. Contaminant Al2O3 inherent within clay pods can result in CID material outside of crusher feed grade specifications, causing it to be flagged as ‘internal waste’ in mining models and permanently lost to waste dumps. In 2011, after multiple tests, Mine Geology demonstrated that this material could be upgraded to crusher feed via wet processing. With the support of the RTIO Metallurgical Development team new grade specifications were defined. The resulting material has been used to supplement higher grade ore. While increasing the mining ore output, these ongoing value-adding strategies also promote more sustainable mining via better use of the non-renewable iron ore commodity. The initiatives extend mine life, reduce waste movement, improve strip ratio and increase productivity

Mar 22, 2022

By B King

A large number of mineral deposits contain regions in which it is economically beneficial to extract ore both via open pit and underground mining techniques. Current industry practice lacks an effective means to establish the extent of the open pit and underground mining areas for an individual deposit. We present a mixed integer programming model for scheduling both the open pit and underground mine that can be used to create a holistic extraction sequence for a specific deposit. The model considers both spatial and temporal elements of the open pit and underground mines in order to maximise the net present value of the entire deposit, while adhering to its production, processing and block sequencing constraints. By doing so, we can schedule the open pit and underground in concert.CITATION:King, B, 2014. Modelling open pit and underground production scheduling in concert, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 369–374 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By R Ahola, M D. Henschel, M A. McParland

With the introduction in recent years of third-generation interferometric synthetic aperture radar (InSAR) techniques, monitoring of mine slopes, benches and surrounding areas has benefitted from increased accuracy and coverage. Fundamental research into point and distributed scattering techniques has pushed the use of InSAR to provide higher spatial and height resolution. In this paper we discuss the operationalisation of third-generation InSAR techniques and show its application to active mining operations.This paper will discuss the use of multiple independent measurements of ground movement obtained from operationally-derived InSAR products over a wide variety of deformation areas within an active open pit mining operation (ie pit slopes, dewatering depressions, tailings containment and waste dumps). A technique that shortens the time between observations (increased observation frequency) and provides ongoing estimates of measurement accuracy will be described. The methodology exploits available satellite data by using multiple satellites and multiple beams. The paper will also examine factors in the design of a mine survey with third-generation InSAR and illustrate some of the necessary engineering trade-offs to efficiently monitor a mine from space.Overall, this paper aims to demonstrate the capabilities and advantages of operational third-generation InSAR techniques for ground movement monitoring of mining operations and provide a framework for proper design of a mine InSAR survey.CITATION:Henschel, M D, Sato, S, Ahola, R and McParland, M A, 2014. Designing interferometric synthetic aperture radar surveys for mine monitoring with accuracy assessment, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 233–238 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By V Rasouli, G Cavanough, A Mokaramian

The sampling time, the costs and its quality are the three factors that determine the best method of drilling in mineral exploration. The two principal methods of reverse circulation (RC) and diamond core drilling are often used in combination by mine operators. RC is used for drilling shallow holes and in-pit grade control, and core drilling for deeper holes to identify future resources. The RC method is faster and more flexible than coring and provides virtually uncontaminated cuttings (ranges from dust to 25 mm chips) to the surface cyclone suitable for geochemical anomalies. The diamond coring produces core samples to increase the level of geological knowledge and the 3D extension and distribution of the orebody. However, both of these methods are subjected to certain limitations and inefficiencies in reaching deeper depths and drilling complex hole geometries. Examples of such shortcomings include the inability to provide enough air pressure for RC drilling and high friction between drill pipe and the hole wall in diamond core drilling.Considering that delivering large volume of reliable samples from deep zones to the surface in shortest possible time is of paramount importance in mineral exploration, and assuming that obtaining core samples over whole overburden is not always essential, then drilling small size holes as fast as possible and delivering the small chip samples to the surface would be a good alternative with several advantages over conventional drilling methods for deep hard rocks mineral exploration. As a result, the use of coiled tube (CT) drilling technology has been proposed recently for such applications. CT is a continuous length of ductile steel or composite tube stored and transported on a large reel; and allows fast drilling by eliminating the connection time and providing continuous circulation during drilling. This enables quick access to the zone of interest to collect the cuttings or obtain core samples. CT is advantageous particularly in drilling directional boreholes and multi-laterals. In this paper, feasibility of using CT delivering reliable samples is discussed for deep mineral exploration. In addition, recent developments and practices are presented that make CT a reliable drilling technology to drill cheaper, faster and deeper and to deliver more continuous and reliable data and samples from deep formations.CITATION:Mokaramian, A, Rasouli, V and Cavanough, G, 2012. Quality sampling using coiled tubing drilling in deep mineral exploration, in Proceedings Sampling 2012 , pp 73-80 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 21, 2012

By T A. J Hopper, S Mukkisa, K-O Ott, D Palmer

RIG Technologies has developed new technology that can successfully acquire high quality natural gamma ray (GR) and hole deviations, downhole while drilling, on reverse circulation drills. This technology survives the hostile downhole environment with shocks of between 400–2500 g for 7– 10 days at a time. The Logging While Drilling (LWD) service eliminates the need to run in-rod surveys, either by the driller or by wireline trucks and crews. This time saving is in the middle of the drilling process, thus enabling drills to keep drilling and increase their productivity. Additional to the natural GR and directional survey, the downhole tool is equipped with sensors to measure the downhole dynamic response of the drilling system providing insights into rock hardness, density and potentially clay types. These parameters have never been acquired behind the hammer before and coupled with surface measurements from the drills themselves, form a rich data set for trainable machine learning algorithms shortening the time to receive advanced geophysical answer products from sometimes months, to live feeds directly from drills (Hopper, 2019). Alive, high speed, two-way data link between surface data acquisition systems and downhole geophysics tools has been established and incorporates calibrated surface measurements of dynamic forces directly on the drill string to match up with those measured downhole. Receiving live streams of natural GR and hole deviation surveys as the drill is drilling allows true remote decisionmaking with live data available anywhere in the world. The combined data from surface and downhole dynamics builds a data set that could begin to enable true optimisation of autonomous drilling processes.

Nov 8, 2021

By M Andrew, D McTiffen, M Adams

A major Ventilation Upgrade Project commenced at the Fosterville Gold Mine (FGM) in 2017 to service the ongoing ventilation requirements of the underground mining operation. The project consists of three large diameter ventilation raises totalling 1100 metres, and new axial primary ventilation fans to upgrade the mine ventilation system. With a mining depth of 1200 metres and a thermal gradient of approximately 2.7 °C per 100 metres of depth, the completion of the Ventilation Upgrade Project is key to the ongoing success at FGM. The Ventilation Upgrade Project will allow continued mining, including high-grade gold deposits, lower in the mine where heat is increasing. Figure 1 below illustrates the underground workings at FGM, and provides a general view of the ventilation upgrade works to establish the new exhaust system from the lower workings to surface. Whilst raisebore pilot drilling the H4760 Return Air Rise (RAR) from surface to 395 metres, the raisebore drill string became stuck in the raisebore pilot hole at approximately 300 metres down hole, presenting a significant technical problem and delays to the project. This Case Study provides an overview of the recovery process undertaken at FGM including the recovery of the stuck drill string. The value of the stuck in-hole equipment, the investment in the shaft site preparation, the collar stabilisation, the underground development to the base of the ventilation raise, the surface footprint prepared for the Primary Fans construction and the limited available space on the site were all motivations to recover the raisebore drill sting and ultimately recover the ventilation raise location. More importantly, the long lead-time required should a new shaft location be the final solution, and the delay this would incur to the ventilation upgrade was unacceptable. Recovery of the drill string was not possible using the capability of the Contractor’s Raise Drill. An alternative method for freeing the drill string was required. A significant amount of engagement with industry was undertaken to seek out potential solutions and draw from the experience of others. All methodologies available were considered and assessed. Ultimately, after several attempts at freeing the raisebore drill string using various methodologies, Adams Drillers and Clear Cut Interventions were engaged to provide a turnkey recovery solution.

Mar 15, 2021

The current economic climate and demand for iron ore has resulted in mine operators being prepared to accept aggressive slope designs and associated failures provided that they can be quantified (ie volume of failure and clean up costs, etc) and incorporated into the mining costs, at a feasibility study level. This has numerous implications for pit slope design/geomechanics. Typically when geotechnical engineers conduct slope stability modelling a single value, usually the average or mean value for model input parameters (ie structural orientations, material properties and hydrological conditions) are chosen. The implications resulting from using a single value for model input parameters will vary depending on how the modeller has chosen the value, ie should the modeller choose a mean value from a log-normal distribution of material strengths an optimistic representation of the stability may eventuate, consequently if the designer decides to conservatively downgrade the values by a nominal factor, a pessimistic representation of slope angles may occur, which would result in excessive stripping and mine development costs. A more realistic and representative way to model the inherent variability of geological/geotechnical conditions would be to do so probabilistically. Whereby the modeller can assess the variability of the geological structure as observed/recorded during the core logging process and a similar approach for the material strength properties. The final model output would be a distribution of factors of safety in relation to overall slope angles, ie probabilities of failure for individual slope angles could be determined. This output (graph) could be modified by the mining engineer to incorporate mining costs as well as clean up costs for the respective slope angles and associated failure volumes, ie probabilities of failure. The author intends to provide a detailed overview of the processes involved in deriving a geotechnical design, ie; starting from the data collection phase (core logging/face mapping), through to the data interpretation and formulation of slope parameters; determining the variability and uncertainties associated with each of the process; ensuring that it is adequately captured in the model input parameters; and how the mining engineer could utilise this information to derive final feasibility study mining costs.

Jan 1, 2009

By A Chadwick, J de Ross, C Adams

Imagine a æshinyÆ new mine, $1 B in the bank and record commodity prices. So how does a company and its management team create enough tension to maximise profit and to establish a culture that can weather the good and bad times?That was exactly the situation the team at OZ MineralsÆ world class Prominent Hill mine in South Australia faced in 2009.Three years later, the harder times have come - lower though still healthy commodity prices, rising industry costs, fierce competition for talent, geological and technical issues (common to developing mines). However, the company was able to maximise profit during the good times and equip the culture to deal with the tougher times with minimal turnover.Through the combination of simple systems and processes, people development, application of commercial technical acumen and a combination of yin and yang leadership, OZ Minerals has achieved something quite rare - sustainable continuous improvement.The journey started with a vision. The EGM Operations created the æsparkÆ. The dream was to create a æfranchise mineÆ that could be rolled out to new mines and acquisitions as the company grew. However, the real leadership came from his lieutenants who provided the important yin and yang. The GM commercial provided the tools, processes, systems and the bottom line focus. The GM operations focused on culture, leadership, training and sustainability. This powerful combination (along with some good old persistence) was able to create the critical mass required to make continuous improvement go æviralÆ.This paper explores this unique case to uncover the essential ingredients that were created and mixed together. It will touch on the key human, technical and system elements that helped achieve significant improvements in plant recoveries, mine throughput and operational efficiencies, while overcoming human capacity, geotechnical and contractual challenges.CITATION:de Ross, J, Chadwick, A and Adams, C, 2012. How to create a perfect storm, in Proceedings International Mine Management 2012, pp 239-250 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 20, 2012