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By H Chalcraft, T D. Mullen

Conditions encountered at a recently completed brownfields mining project provided valuable insight into, and development of, techniques for working in and around known underground mining voids in an open cut environment. The careful application of underground blasting principles to a pit environment and successful excavation whilst maintaining appropriate stand-off distances were two primary areas of innovation enabling the success of the project.Mary Mac Hill is a gold deposit situated less than 2 km south-west of the town of Laverton, Western Australia. It is owned and mined by Crescent Gold Limited. Previous underground mining by various other mining companies has left an extensive network of underground horizontal development, subvertical stopes and shafts, some of which daylighted at surface. This was identified as potentially posing substantial risks, which would prevent the application of conventional mining methods. Two major stopes were located under a hard banded iron ridge topped by a peak of cap, connected variously by narrow drives and vertical development. Due to the proximity of the first of these stopes to the surface, its dimensions and governed by procedures and advice provided by externally engaged engineers, Crescent Gold could not access the area of the ridge immediately overlying the stope using conventional open cut mining methods. This was the first of many hurdles surmounted in mining this deposit.The following report outlines how the challenges this geometrically complex deposit presented. Solving these problems enabled the team to mine the contained gold ore to a completed design, without subjecting personnel or mining equipment to harm due to a void breach incident. This paper outlines the numerous complications and difficulties Mary Mac Hill posed and explains the strategies developed to overcome them. The report also presents technical mass blasting details explaining two of the critical crown pillar blasts.CITATION:Mullen, T D and Chalcraft, H, 2012. Mary Mac Hill - The challenges and strategies of successful open cut mining: A complex underground gold deposit riddled with a network of complicated voids, in Proceedings Eighth Open Pit OperatorsÆ Conference , pp 89-96 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 18, 2012

By M Frenzel

At the last MassMin Conference in Sudbury, Caterpillar’s vision of a continuous mining concept for block caving operations was presented on the background of global raw material demand and its continuous increase. By analysing today’s structure of mining processes in block caving, the paper (Krings, Steinberg and Frenzel, 2012) highlighted the main bottlenecks in the process chain and identified conceptual solutions by help of a case study. The main focus was the paradigm shift from discontinuous batch type operation to a continuous mining process of the blocks.In 2016, the strategic vision has taken major strides forwards and remote continuous operation has become a reality. Caterpillar’s continuous operation system – the Rock Flow system – was successfully installed in Codelco’s Andina mine and start of operation is scheduled in the first half of 2016.Based on continuous product developments, this paper sets the focus on two main aspects of continuous mining. First, field experiences of the Rock Flow system will be shared, highlighting the Andina project course from system installation, to commissioning and successful system start. The second aspect concentrates on the system and mine layout as discussed in the case study scenario in MassMin 2012 (Krings, Steinberg and Frenzel, 2012).Based on Caterpillar`s continuous product development, the Rock Flow system set-up and panel design were modified for a general roadway design and drawpoint layout. The new design allows an optimised use in block preparation phase (spreading) and full production phase (reaping), operating a fleet of load-haul-dumps (LHDs) and Rock Flow systems. The combined use of the two technologies optimises the mining process in every stage of block life and significantly increases the performance of the continuous block caving operation in the production panel to pave the road for the next generation of super caves.CITATION:Frenzel, M, 2016. New continuous production system in block cave mining – the rock flow system, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 543–548 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By L Galisson, E Audigé, D Sowers

Establishing a robust geotechnical instrumentation and construction monitoring plan is one of the keys to the successful delivery of the world’s largest soft-ground bored tunnel in Seattle, Washington. The paper describes and provides a return of experience on current and best practice for monitoring tunnelling projects in urban areas. The owner’s contractual approach is discussed to highlight the flexibility of the design-built contract in achieving equal or better solutions by allowing for the use of innovative technics. Special attention is given to the management and involvement of third parties (building owners, utility owners), including the public, to overcome all challenges faced during the installation of the monitoring system in downtown Seattle for over 1000 instruments. Finally, the authors present the strategies implemented for managing the monitoring data and communicating with the owner, contractor and stakeholders.CITATION:Sowers, D, Galisson, L and Audigé, E, 2014. Current and best practice for monitoring tunnelling projects in urban areas – Alaskan Way bored tunnel, Seattle, Washington, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 441–450 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By M Goers, M Almond

"The use of reverse circulation (RC) drilling for grade control sample collection was selected by the Pueblo Viejo Mine Geology department at the recommencement of the operation in 2010. This method was selected because it allows: for multi-bench drilling (60 m hole depth, four benches of mining) to aid mine planning and provide a detailed close spaced drill data comparison with the reserve model angled drill holes to optimise the drill hole interception of the vertically controlled mineralisation dry sample collection in areas of excessive surface and groundwater mining operations to commence with the long assay return period (due to the need for the samples to be shipped overseas for analysis) until the on-site laboratory is operational.To date, 118 302 m of drilling has been completed throughout the operations of two open pits: Monte Negro and Moore. Two drill rigs (contractor and site-owned and operated) with three generations of sampling systems have been used to date. Throughout the drilling a 20 per cent quality assurance, quality control (QAQC) sample check (blanks, field duplicates and standards) have been used to check the drilling and laboratories performance. In addition, a total of 1104 fines samples were collected to compare the drill chip samples collected and the fines lost with two of the sample systems used.The drilling to date has highlighted the need for a complete and coordinated system to be used before sufficient confidence in the quality of the samples collected is achieved.The complete system must be set-up and coordinated to obtain the best quality sample possible. This complete package includes: drill bit size and shape for the rock being drilled and mineralisation targeted face sampling hammers with the correctly sized hammer shrouds sample hose routing to reduce sample flow turbulence and choking blow-down valves to eliminate drill hole water that has entered the drill string during rod changes correct drilling techniques targeting sample quality a sample system that captures the fines for inclusion into the sample.These improvements can be obtained without reducing the drilling rates.The measurements required to demonstrate the improvement in the sample quality will be the focus of future work within the department.CITATION:Goers, M and Almond, M, 2012. Bit to bag - The importance of a total coordinated system in reverse circulation drilling, in Proceedings Sampling 2012, pp 65-72 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 21, 2012

By G Booth

Whilst communications systems in the mining industry have evolved over the years, the premise remains consistent that reliable communication is vital for safety and operational efficiency. TodayÆs open pit mines are benefiting from advanced developmental efforts based on mesh networking hardware and software technology. This paper highlights Rajant CorporationÆs adaptation of technology, originally developed for the defence and first responder industries, to provide wireless network connectivity in open pit mining applications. Featured is the large-scale deployment of over 300 mobile, meshing access points in the Bingham Canyon Copper mine near Salt Lake City, Utah, the worldÆs largest open pit copper mine. Many companies have positioned themselves, their technology and their product line in the arena of rugged outdoor wireless broadband mesh networking infrastructure. However, Rajant Corporation has combined specialised command and control software and portable networks which offer network extensibility and redundancy that are not available in any other networking solution. Rajant CorporationÆs BreadCrumb« offers unique traits in portability and non-line-of-site networking nodes which intelligently route and broadcast in standard 802.11 protocol. The advantage of RajantÆs solution is especially valuable for users needing equipment moved easily and rapidly into and out of the theatre of operations with uninterrupted network availability. The main differentiators that set the BreadCrumb« network apart from the competitors are mobility (continuous availability), simplicity, ability to properly load balance and power options. In 2007, RajantÆs BreadCrumb« wireless mesh system was selected by the Kennecott Utah Copper Corporation (KUCC), a wholly owned subsidiary of Rio Tinto, as its primary communications platform for operations within the Bingham Canyon Copper mine, the worldÆs largest open pit copper mine. The Rajant BreadCrumb« technology enables KUCC to gain additional operational efficiencies by tracking, monitoring and managing its copper mining operations. The primary goal of using the BreadCrumb« wireless mesh system Kennecott was to streamline its complex mining operations. KUCC required a high number of moving wireless nodes for improving mine monitoring and control. The Rajant InstaMesh« software running on the wireless BreadCrumb« units connects hundreds of devices to each other while rapidly transporting critical operational data. Kennecott has successfully implemented a large number of BreadCrumb« radios in an interconnected network that allows loader trucks, shovels, pumps, laptops and other production equipment to communicate with each other in real-time. These systems are a mix of secure access nodes that enable data and voice communications across a meshed, self-healing network for fleet dispatch, health monitoring and other critical mining applications. Many of the devices that require wireless communications are moving at all times throughout the wireless mining infrastructure. The BreadCrumb« nodes rapidly adapt to any changes in the network topology, assuring that IP traffic uptime and bandwidth are maximised. The installation layout and data network specifics, as well as maps and data network efficiencies will be detailed in the paper.

Jan 1, 2008

By S A. McManus

With the advances in software speed and capability, many of us now are running multiple scenarios on entire models rather than just testing small areas or a few blocks. In the authors experience both the geological and geostatistical academic theory and our rules of thumb, often prove un-useable or incorrect in the real world we work in. The only way to truly validate and tune our models is to complete the entire model and ‘see if it works’. If it lacks some property we were expecting, then we need to find out why and/or run different scenarios to see what changes. This is not always possible with tight project timelines but we find ourselves doing more and more of this sort of thing, and in so doing, understand that every deposit is different and requires its own ‘rules’ to get valid and useful results. For the purposes of this paper, this process is termed Empirical Geostatistics. Take Clayton Deutsch’s ‘all realisations all of the time’ concept a step back. Before you even think of simulating, test the alternate realisations generated by alternate parameters such as different domaining, varying search neighbourhood parameters etc.

Mar 22, 2022

By G Davison, C Rossimel, M Bouazza

Expanding rock bolts anchor within a rock mass more efficiently than non-expanding varieties. This is of great importance in weak ground conditions, where grouted friction bolts perform less efficiently than in good ground conditions. Filling a Split Set with demolition concrete has been shown to double the load-carrying capacity when compared to conventional use of Split Sets. This report details verification of these results by installing and pull-testing 14 Split Sets of varying grout conditions within in a fault zone. These Expanding Split Sets achieved loads double and triple that of ungrouted and normally grouted conventional Split Sets. A literature review and chemical analysis were conducted to understand the expansion process better. It was found that 20 per cent more calcium is included in expanding cement, which is responsible for its growth. Factors most affecting the expansion process were identified. Furthermore, the expansion rate of a bolt outside a borehole was measured and 6 mm of expansion across its diameter was found. The compressive properties of the cement were compared with other types, due to expanding cement becoming uncohesive after the expansion process is complete. When confined within a Split Set, compression testing demonstrated that this grout is just as strong and rigid as normal grout. Finally, the bolts were tested by shear and it was found that the Expanding Split Set (ESS) has a similar shear capacity to grouted Split Sets, which is 70 per cent higher than that of ungrouted Split Sets. These results enabled the mechanism for improved performance in weak ground conditions to be verified. Expanding grout will expand the Split Set into its borehole of varying diameter and lock it into place, creating increased friction and resistance to pull-out. This paper shows that ESSs can be a useful reinforcement technique in weak ground conditions.CITATION:Rossimel, C, Davison, G and Bouazza, M, 2014. An investigation of expanding split sets in weak ground, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 159–170 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

By J Carrillo, A King

Gravity recoverable gold (GRG) is largely distinguished from other gold by its non-mineralised, metallic form, its high degree of liberation from the ore and its appreciable particle size. The gold mining industry has so widely accepted the use of batch centrifugal concentrators (BCC) and intensive cyanidation (IC) systems for the recovery of GRG that these may well be considered requirements of any plant processing ore containing appreciable GRG. The recovery of gold by gravity is quick, easy and cheap by comparison to alternatives. However, there are cases where attributes of the ore make recovery of gold by gravity and IC unusually challenging. This paper describes three examples where such challenges have been encountered and met, including those where the ore contains cyanide soluble base metals and where fine GRG is to be recovered from flotation concentrate.CITATION:King, A and Carrillo, J, 2018. Addressing challenging applications of intensive cyanidation in gravity gold recovery, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 283–290 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By R Hughes

"Spring Creek Mine uses high pressure water to extract the thick Main seam in the Upper Rewanuicoal measures. The extraction method results in the creation of large voids which collapsespontaneously. This can result in the displacement of large volumes of methane, which may create a signifi cant hazard if not correctly managed. A system of automatic dilution doors is employed to mitigate this risk. This paper describes the evolution of the system and gives some examples of its eff ectiveness."

Jun 1, 2012

By G R. Power

A useful way to assess potential productivity of SLC mines is by quantifying tonnes/drawpoint/day to be extracted from the mine. However limited industry information has been published to help mines benchmark this number. This paper assesses industry data which can be used to support estimates of potential productivity from new mines based on tonnes/drawpoint/day. The information used has been extracted from historical production schedules which indicate what was achieved, rather than what was planned. It has been assessed using an algorithm created for the purpose and is presented with discussion of varying definitions of active drawpoints, analysis of the data and inquiry into some of the underlying contributing factors.

Mar 15, 2021

One of the earliest and continuing challenges in driving sustainable development in large scale resource industry projects is around the issue of assessment û how do you measure the sustainability of a mineral operation? One of the key road blocks when confronted with this challenge is the temptation of technical folks to reach for a definition of sustainability or sustainable development. But definitions, by definition, have boundaries and limitations that serve to constrain thinking û they limit the thinking of what we can achieve with sustainability (it also acts as a barrier that constrains innovation). Rather than seeking definitions, better understanding of the core perspectives around sustainability and their application to the minerals industry provides a much more powerful platform from which to conduct assessments. But it is only when these perspectives are combined with the right framework and supporting techniques that the complex becomes doable. With the support of the perspectives and the framework, various assessment and measurement methodologies can be used; the challenge is communicating to stakeholders the sustainability character of the project in ways that are meaningful and to which people can connect. Assessment is not about finding the best or most accurate methods that fulfil strictly academic and possibly abstract requirements. The challenge is to help people understand what the impacts are, and what the value contributions will be, in a format and language that make sense in their world-view.

Jan 1, 2009

By D Brereton, C J. Moran

Intensive resource extraction, in the form of multiple mining operations, presents significant assessment and management challenges for resource developers, governments, community and the environment. Cumulative impacts, ie the successive, incremental and combined impacts (both positive and negative) of an activity on society, the economy and the environment, can place significant pressure on social, economic and environmental capital and render conventional mine-by-mine approaches to management ineffective. Cumulative impacts can be what are most important to environments, communities and economies surrounded by multiple mining operations because cumulative impacts are what they experience. There is much to gain from increased consideration of cumulative impacts. Unmitigated impacts have the potential to delay or even prevent expansion of mining in existing and prospective areas. On the other hand proactive management of cumulative impacts can benefit regional environments and communities and contribute to the industryÆs social license to operate. Resources are often not the limiting factor to better cumulative impact management. More effective coordination of existing resources may go a long way toward mitigation and enhancement, and better planning and assessment may help avoid impacts and exploit opportunities for efficiency gains through reduced duplication. In this paper we draw from working examples to present five practical assessment and management strategies applicable to resource companies to enhance positive, and avoid and mitigate negative, cumulative impacts. The strategies are presented based on their capacity for achieving outcomes, ease of implementation and cost effectiveness and are drawn from a multi-year study on the assessment and management of cumulative impacts in the Hunter Valley, New South Wales and a follow-up study to improve cumulative impact assessment and management practice in the Australian coal mining industry, both reported elsewhere.  

Jan 1, 2009

By S J. Clarke, G Sieders

Double corrosion protection (DCP) rock bolts have evolved to become complicated assemblies comprising numerous components. This complexity is mainly associated with durability considerations including potential exposure to adverse groundwater conditions and ensuring separation of dissimilar metals within the bolt assembly itself.Recent progress in the construction of glass-fibre reinforced polymer (GRP) rock bolts have the potential to provide a viable alternative to conventional steel rock bolts in civil tunnelling applications. The durability of the material results in a much simpler bolt detail and permits the use of resin rather than solely cement based grouts.This paper presents the findings of the comparative structural testing of GRP bolts with conventional DCP steel bolts. The axial load performance, including stiffness, ultimate capacity and ductility of bolts are compared. Shear behaviour of bolts is considered, including durability issues associated with damage to the plastic sleeve used in DCP bolts.The paper also considers other issues which are relevant to the design of temporary and permanent rock bolts used in tunnel support, such as initial tensioning and grouting. Long-term performance, including durability and creep are also reviewed.CITATION:Clarke, S J and Sieders, G, 2014. Comparison of glass-fibre reinforced polymer rock bolts with double corrosion protection steel rock bolts for use in tunnel applications, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 237–246 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By C G. Sweeney

The underground mining industry is seeing unprecedented shortages in skilled labour. Migration to Australia being at an all-time low is a leading concern, with pandemic-induced border closures and lockdowns only exacerbating the skills shortage, not causing it. The skills shortage is forecast to peak in 2023 and remain high beyond 2025. With this skills shortage in mind, mining companies throughout Australia are trying to deal with stricter protocols around Health and Safety (H&S) legislation, as well as more stringent controls on quality assurance, particularly as underground mines are reaching greater depths and extending into ‘unchartered territory’. The cumulation of this is proving to be a major hurdle in ‘effective’ operational geotechnical management. The drive for automation in mining is bringing another level of complexity. However, ‘once automation is up and running, it presents the opportunity to access talent pools that may not normally be available. There is also a change in skillset that will be required to drive automation. ‘The top two emerging roles that will be critical for the future of the mining industry are artificial intelligence and machine learning (AI/ML) specialists, and process-automation specialists’ (Writer, 2021). If anything positive has come from the pandemic, it has shown that remote working can be effective and that the drive for automation and critical evaluation of skills required on-site should be given greater priority. UQ acknowledges that the industry is changing, and that digital technology is required to be offered in mining related disciplines. Industry and academia need to do more to promote geotechnical engineering in mining and balance the curriculum to suit the future of mining and make it more enticing. The average cost of a geotechnical failure is about $5 million in coalmines and can be into the hundreds of millions of dollars if production is affected (Cartledge Mining and Geotechnics, 2020). The cost of a good geotechnical design far outweighs the potential losses if a failure were to occur. This alludes to the growing importance of experienced geotechnical consultancies playing a pivotal role in managing mine site geotechnical hazards, while the industry is developing the next generation of geotechnical engineers.

Nov 29, 2022

By C Armstrong, B Wentzinger

Upstream embankment raises often represent the lowest cost option for increasing the capacity of tailings storage facilities (TSF), but also pose the highest stability risk due to constructing on top of previously deposited tailings.This paper presents an overview of key aspects in the geotechnical investigation and design of upstream raises and some recent lessons learnt from experience across a number of TSFs in Australia. A summary of recommended field investigation and laboratory testing methods is provided with a focus on collecting quality information for design purposes. A strong focus is given in developing an accurate assessment of pore water pressures, which, if not correctly understood can have disastrous consequences on tailings strength parameter interpretation and wall stability assessment in static and post-seismic conditions.The assessment of the contractive or dilative shearing behaviour of the tailings material and rigorous interpretation of design characteristic values are presented. Some comments on stability analysis options and proposed methodology are also provided.CITATION:Wentzinger, B and Armstrong, C, 2018. Lessons learnt in geotechnical investigation and stability analysis for upstream tailings storage facility raise design, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 333–348 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By R Austerberry, S Green

The discovery of the Cuffley Lode at Mandalay Resources Costerfield Operations provided an opportunity to extend mine life via mining the offset depth extension of the previously worked Alison Mine. Access from the existing Augusta Mine placed the initial Cuffley underground workings at approximately 250 metres depth from surface. As the new orebody transitioned towards production, a secondary means of egress needed to be established. The depth of the initial capital development presented a challenge in establishing a secondary means of egress that could be confidently relied on. The availability of land to locate a surface shaft collar further reduced available options and geotechnical drilling further limited suitable shaft locations. Time limiting factors such as permitting and having a secondary means of egress in as soon as possible, further highlighted that an innovative secondary means of egress was needed. A consideration of using an emergency gig lowered by a suitable sized crane supplied by an external crane contractor was investigated and found to be a suitable outcome. This Emergency Gig was deployed via the Cuffley Return Air Raise. When trialled, the emergency gig was found to provide a reliable, repeatable extraction method with an acceptable level of risk. Issues discovered during such trials further improved the process to a point where this extraction method became the adopted secondary means of egress for additional lodes that existed at depth. When assessing possible methods of secondary means of egress, the use of a third-party crane and custom designed and fabricated emergency gig should not be discounted. Where a crane can be sourced within an acceptable timeframe, the emergency gig extraction method provides a reliable safe and cost-effective means of secondary means of egress, especially when multiple shafts are to be developed. Local laws may negate the ability to employ such a system, although it is believed with good communication and well-constructed risk assessments, this system can be safely deployed.

Mar 15, 2021

By G S. Beros, K M. Edwards

Over the past 20 years drum scrubbers have become a widely adopted technology within iron ore beneficiation plants. Generally, the drum scrubbers in use are considered high-capacity machines capable of accepting larger-sized feed material. Together with a water addition to a desired pulp density and a mild energy input, these large rotating machines effect an attritioning action that removes water soluble clays and other deleterious materials. Within the Western Australian iron ore industry, drum scrubbers have been successfully applied to Channel Iron, Marra Mamba, Bedded and Detrital orebodies. The introduction of drum scrubbers has enabled Western Australian producers to satisfy the substantial increase in demand for iron ore from Chinese steelmakers by making the lower-grade sections of the above orebodies economic. However, despite being a relatively simple unit process, the requirements for successful design and operation of these machines are not fully understood. This paper draws on the collective experience of both authors to provide some points to consider for incorporating drum scrubbers into iron ore beneficiation plant flow sheets.

Sep 18, 2023

By L Sandery, S Light

Within 22 months of commencing decline development, the Prominent Hill Ankata Underground Project achieved its full production rate of 1.2 Mt/a.In 2010 construction of the Ankata Underground Project was approved. Decline development commenced in November 2010 and the turnout for the first sublevel was reached by August 2011. The first stoping ore was produced in the first quarter of 2012 and production was successfully ramped up to full production during the third quarter of 2012.Diamond drilling commenced in October 2011 and was conducted concurrently with the underground development. This presented challenges as mining and production targets had to be balanced with underground exploration activities. To achieve production on schedule, without adversely affecting the diamond drilling program and future development, meticulous and adaptive planning techniques were required. This included involvement from engineers, geologists, underground operators and underground diamond drillers.The granularity of these planning techniques allowed the management and prioritisation of development and diamond drilling down to an almost hourly basis. A constant flow of information from drill assay results was fed back into the planning systems. This resulted in a constantly evolving mine plan as the orebody was further refined. High priority areas were identified and targeted to allow continued development and a successful rapid ramp up to full production.CITATION:Sandery, L and Light, S, 2014. Managing the diamond drilling interactions in commissioning the Ankata underground mine, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 75–80 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

By T D. H McGrath, W P. Staunton

Benchmarking, comparing an operation or process with the industry standard, is known to be a useful method for identifying plant optimisation opportunities, and in many cases providing the pathway to realise the benefits. The difficulty is generating the database of plant data necessary for a benchmarking exercise. Larger companies can benchmark internally; this option is not available to smaller companies, and the full value can only be realised with a comprehensive “industry wide” approach.The Gold Technology Group at Curtin University through the AMIRA P420 series of projects has undertaken several comprehensive metallurgical industry surveys in the gold industry over the last two decades. Analysis of these surveys has demonstrated areas where many operations can benefit from re-assessment of their operating practices.This paper will review the work undertaken by the Group in this area, in particular the 1999 surveys of gold companies in the Australasian region, and the 2012 international survey of the industry. The challenges of, and opportunities arising from these surveys will be discussed. Some of the highlights from analysis of these databases will be presented as well as noting changes in processing practices observed by the Group over the last 20 years.CITATION:McGrath, T D H and Staunton, W P, 2018. Keeping up with the Joneses – the value of industry surveys and benchmarking, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 509–516 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By S Long, D Carnovale, L Louwrens

The Mt Wright underground mine (MTW) is located near the town of Ravenswood in north Queensland and is operated by Carpentaria Gold – a wholly owned subsidiary of Resolute Mining Limited.The Mt Wright mine has gone through many stages, from the conception and implementation of the world first ‘sub-level shrinkage’ stoping (SLS) with continuous fill mining method in 2010, through to steady state production. These have been outlined in detail in papers presented by Mackay (2011) and Mackay, Long and Koen (2014) at previous Underground Operators Conferences.Since the last paper was presented, MTW has experienced significant change in two key areas.The first significant change was the discovery of a previously unknown hazard in the form of flat rilling events (FREs) from closed drawpoints (DPs). These events are believed to be unique to MTW and pose a significant risk to both the safety of personnel and the business as a whole. The paper will discuss this hazard and the evolution of the controls and practices that have been introduced to mitigate the risk posed by the identified hazards. The material involved in these events is extremely dry, fine and hot.The second significant change is an altered stress regime bought on in part by a change in the production front orientation and a general deterioration in ground conditions in some areas of the mine. This has caused some production interruptions at MTW. The second half of the paper will describe the challenges encountered, the mechanisms behind these challenges and the strategies implemented to safely return MTW production to planned levels.It is believed that other operations can learn from the issues mentioned above, and the paper has been written with this in mind.`CITATION:Long, S, Carnovale, D and Louwrens, L, 2017. Mt Wright – managing unique risks, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 295–304 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017