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By P Craig, A Crosky, H Ramandi, S Saydam, H Chen

Frequency of reports on premature failure of rock bolts and cable bolts have increased in past two decades. Such a failure threatens both the safety of underground mine workers and the economic viability of the operations. Herein, we report on analysis of rock bolts and cable bolts failed recently in three underground mines in Australia. Magnetic particle inspection (MPI) and scanning electron microscope (SEM) techniques were used to study the failed bolts. MPI showed a number of subcritical cracks on the surface of the bolts. The majority of the cracks in both cable bolts and rock bolts were initiated from the base of ribs (indentation) where the stress concentration was high. SEM examinations showed tearing topography surface (TTS) in all failed rock bolts and cable bolts. These indicated that the failure occurred through hydrogen assisted stress corrosion cracking (HISCC). The results of this study enhanced the understanding about the failure of rock bolts and cable bolts in underground mines. CITATION:Chen, H, Ramandi, H, Craig, P, Crosky, A and Saydam, S, 2018. Analysis of premature failure of rock bolts and cable bolts failed in underground coal mines, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 407–413 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By M Jones, G Corder, A C. Keith

"Sustainable development has become an issue of ever increasing importance to the mining industry. The Ernst & Young (EY) mining industry risk radar regularly shows several sustainability elements in the top ten risks, with social license the number three risk in the 2014/15 survey. This is supported by the Fraser Institute survey results of 2013 showing that 36 per cent of responding companies indicated public opposition had affected their permitting and approvals process.Addressing these issues in a strategic way across a mining business that is then translatable to actions at operational level has remained an elusive goal in the industry. In addition the environment and community issues are commonly viewed as somewhat separate from financial and production issues and as a compliance cost rather than a value add. In their Harvard Business Review paper of 2011, ‘Creating Shared Value’, Porter and Kramer outline changes in thinking required for companies to improve their business sustainably through considering the societal issues impacted by their operations and products. Along the lines of ‘doing more with less’ companies’ value chains can be redefined to reduce energy, transport, water or other resource usage leaving additional resource for societal usage and/or reducing environmental impacts. This paper explores the linking of the holistic Five Capitals-based approach with the creating shared value (CSV) concept to help businesses unleash the benefits of innovation. Previous papers have demonstrated the potential for Five Capitals approach to create strategic value through sustainable development. Building on previous work, this paper provides an overview of the current status of holistic approaches to mine management and presents the application of the CSV concept on an African mine currently undertaking capitals-based strategic planning. The paper also demonstrates the value that has been created through utilising this approach and proposes improvements for changing the way the industry tackles and delivers benefits related to sustainability issues.CITATION:Keith, A C, Corder, G and Jones, M, 2016. Strategic sustainable development – creating shared value in the mining industry, in Proceedings International Mine Management Conference, pp 249-264 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 22, 2016

By G R. Ballantyne, V Souto, K Bartram

Particle sorting allows partially liberated minerals to be separated prior to energy intensive fine grinding. Sensors select particles for separation and air, water or mechanical ejectors are used to physically deflect those selected. To achieve effective separation there has to be sufficient liberation, accurate detection and presentation of a separated monolayer of particles. These three physical constraints determine the particle size limits, the sorting technology utilised, the separation efficiency, and the throughput that can be achieved. The combination of all these factors controls the effective limits on the degree to which sorting can reduce the specific comminution requirements and increasing energy efficiency. This paper will explore two case studies: the application of sorting in base metal mining and precious metal mining.CITATION:Ballantyne, G R, Hilden, M, Bartram, K and Souto, V, 2018. Characterising energy efficiency of particle sorting, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 531–540 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By W Mahoney, F Clement, E Saraiva

Prefabricated waterproofing sheet membranes are extremely complicated to install in underground sections with complex geometries and, despite being already subjected to quality tests in the factory, the installed membrane often exhibits leakages due to different reasons. Main sources of leaks are the required high amount of welding seams and damages caused during installation of reinforcement, as well as overstretching and poorly installed secondary concrete linings. Also the design of the tunnel lining is strongly influenced and limited by the use of prefabricated waterproofing sheet membranes. The use of sprayed waterproofing membranes for more than a decade has contributed to durability and serviceability, as well as to increasing sustainability of tunnel linings. The presented sprayed waterproofing membrane MasterSeal 345 is an advantageous alternative to prefabricated waterproofing sheet membranes under typical tunnelling conditions, especially in geometrically complex areas, such as in lay-by niches, cross passages and crossover caverns, where installation of conventional waterproofing membranes is inherently difficult, and locating leaks is challenging. This membrane has been successfully used in underground projects with different waterproofing design concepts and under diverse hydro-geological and environmental conditions for over a decade. It provides tunnel designers with different options and optimisation for the design of the tunnel concrete lining. Additional advantages to owners, contractors and designers from the use of the sprayed membrane include flexibility in the design, increased productivity and flexibility in working programming, as well as improved logistics, resulting in significant program and cost savings and reduced long-term maintenance costs. This paper describes the key features of this sprayed waterproofing membrane, its application range and limitations, the waterproofing concept, design options and related benefits. Further, guidance for membrane application and quality control and a summary of two recent project references in the United Kingdom and in Switzerland are provided.CITATION:Saraiva, E, Clement, F and Mahoney, W, 2014. The use of sprayable waterproofing membranes in underground structures – concept, design options, benefits and limitations, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 323–332 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By T Ireland

The Project Hobson tunnel excavation was the first use in New Zealand of an earth pressure balance (EPB) tunnel boring machine (TBM). The tunnelling on the project was very successful and break-through was achieved three weeks ahead of program, demonstrating that tunnelling can be undertaken in Auckland with a high degree of cost certainty.Project Hobson involved the replacement of an existing 90 year old above ground sewer that crosses Hobson Bay in Auckland, New Zealand, and which had reached the end of its economic life, with a 3 km long, 3.7 m internal diameter segmentally lined bored tunnel. The NZD$ 118 M project has provided several environmental benefi ts to the Owner, Watercare Services Ltd and the local community:· provide capacity to meet projected growth in the region,· virtually eliminate wastewater overflows into Hobson Bay and the Waitemata Harbour, and· remove an obtrusive visual feature and open up the bay for recreational purposes.Auckland’s bedrock is a weak sandstone/siltstone (East Coast Bays Formation), subject to infilled paleovalleys. The geology in the region has been significantly influenced by volcanic activity; 49 volcanoes are present within 20 km of the city centre.The paper describes the design and construction challenges for the projects, including TBM performance, ‘sticky spoil’ management, and risks associated with basalt lava flows and two paleovalleys. The paper also highlights the reasons for the success of the project, including a rigorous approach to risk management during design, and effective planning during construction. Other useful data such as the effect on the watertable caused by closed face tunnelling, and ‘faceloss’ estimates derived from settlement arrays are included in the paper.Project Hobson also saw the successful implementation of a Geotechnical Baseline Report – one of the first uses of this type of document in Australasia.

Mar 8, 2011

By P Velletri, N Gaylard

The management of wear surfaces in mining operations has remained largely unchanged since the inception of mining. Sacrificial wear liners are installed on the inside of chutes, hoppers and other equipment used to transfer bulk ore to protect the asset from abrasive wear caused by the flow of material. These liners are generally replaced at fixed intervals which may be determined based on historical wear rates or may be driven by other maintenance requirements for that asset. This approach does not always yield satisfactory results, especially for critical assets where the impact of downtime on production can be substantial. For such assets, a condition-based maintenance strategy has the potential to significantly increase productivity and reduce the total cost of ownership associated with the asset. However, for such a strategy to be successful, timely information on the actual condition (remaining thickness) of the wear liners is essential. This paper describes the development and implementation of a wear monitoring system that can be used to remotely and continuously report on remaining liner material thickness in real time. It details some of the challenges that were overcome when developing the system, including the design of a patented thickness measuring system that can be used in a variety of liner materials and is tolerant to the presence of ore on the wear surface. The paper also explains how a cloud-based approach enables data from the wear sensors to be integrated into external systems such as a data historian, which has been demonstrated through a collaborative project with one of the largest iron ore producers in the Pilbara. This ability to combine real time liner thickness information with other data sources, such as throughput, provides the foundation for the transition to a condition-based maintenance strategy.

Nov 8, 2021

By I Gipps

A vision of what the future mine involves all aspects of mining, ie orebody access, ore stoping, material transport, processing and waste material disposal. This paper examines one aspect of the future mine: rock extraction, stoping, automated for remote operation, high productivity and low cost. Concepts for the future require a re-think of the mining process and ROES® re-examines how bulk stoping of ore can be undertaken and how this should be redesigned to accommodate the possibilities that exists with remote control and automated operations.ROES® is a new mining system for underground mines and quarries utilising a shaft located close to or within the stope for the ore breakage process. The system is designed to exclude personnel from contact with production drilling, explosive placement and detonation so all of these tasks are remotely controlled or automated. Survey of the shaft, stope back and broken rock within the stope will occur, following each blast, by remote control or automated techniques. The survey will include excavation geometry, rock fragmentation, geotechnical characterisation and estimation of ore grade. Blastholes will be surveyed before placement of explosives and, with the survey data, the optimal explosive placement and blast timing will be determined with the best available information.ROES® is designed for application in open stoping or sublevel caving in disseminated, geologically defined, thick tabular or narrow vein ore bodies. Technologies developed for ROES® will also have potential applications to caving operations, reducing the risk of frozen ore and poor fragmentation. In a typical sublevel open stope application, ROES® will reduce the stope associated development by half and will allow ore to be brought on-stream sooner and at lower cost. Other savings will flow with the centralisation of mining activities and operational data, reduction in mining fleet, reduction in ventilation requirements, improved occupational safety and reduced mine complexity.

Nov 22, 2011

By S Hille, J Karageorgos

With the increased variability of todayÆs large-scale mining operations, consistent flotation performance is important to improving and sustaining overall recovery through the circuit. The Newcrest Telfer Mine has implemented advanced process control technology to obtain stable level operation and consistent mass pull in the copper rougher and scavenger flotation circuits. The final result has been an overall reduction in variability, which impacts on both copper and gold recovery. This paper describes the methodology and implementation of the improvements in control at the Newcrest Telfer Mine as being an essential part of the business for minerals processing.

Jan 1, 2007

The able address on the currency question given by the Right Honorable A. J. Balfour, M.P., late leader of the Government, at the Mansion House lately, before a large and influential audience, will strike a key-note that will resound throughout the world. It is high time that gentlemen of position and influence should come forward and express their views on this subject, so as to cause the matter to be,more seriously considered than it has been. The question can be no longer ignored or treated with indifference by bankers, financiers, merchants, miners, and others interested in the settlment on some basis the relative values gold and silver bear to each other. It is gratifying to not that such a great leader of political opinion as Mr. Balfour has given serious attention to this important question.The address created a deep impression ,on the minds of many who probably had not given the matter much att.ention, and Mr. Balfour's words will re-echo over a wide range of thought with such effect that I have no doubt they will materially help to check the downward tendency of the value and uses of silver. As a mining engineer, interested in the development of our mining resources for increasing gold aud silver for currency, and having devoted much attention to the subject, I cordially approve of the views set forth by Mr. Balfouf, and I think the general body of all interested in the production of gold and silver will do the same.

By S Pradhan, A Kuras, R Mahajan

This paper describes the design of the precast concrete segmental lining for the 13.1 m internal diameter and 450 mm thick, 2.4 km long mainline tunnels for the Waterview Connection project in Auckland for the New Zealand Transport Agency.The design and detailing of this segmental lining presented some noteworthy challenges, including an alignment that has sections of low cover in soft ground. Key points of interest are that this precast segmental lining is the largest to ever include steel fibres as the primary method of reinforcement and the lining includes cams on circumferential joints to control ring deformation.The paper describes some of the key design decisions that were made in a collaborative manner with the construction team, tunnel boring machine manufacturer, segment manufacturer and the designers.CITATION:Mahajan, R, Kuras, A and Pradhan, S, 2014. Design of segmental lining for Waterview Project, Auckland, New?Zealand, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 289–294 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By Mizuta T, Sakurai M

The Pine Creek Inlier produced 12 440 kg of gold in the period from the first gold discovery in the 1860s to the early-1900s. During the 1930s renewed large-scale prospecting took place and gave a foothold for today's gold mining operations. The rise of the gold price and improved mining methods in the 1970s and 1980s made possible low cost, bulk low grade mining operations. Various gold deposits including vein, network and stratiform types occur in the Pine Creek Inlier (Nicholson and Eupene, 1990). The Tom's Gully deposit is located 100 km south-east of Darwin in the Northern Territory. It is hosted in the early Proterozoic Wildman Siltstone and lies north-east of 1800 my old Mt Bundey Pluton (Figure 1). Around the Mt Bundey Pluton, there are several prospective base and precious metal deposits such as Quest 29. The Tom's Gully gold deposit was discovered in 1986 and yielded a total of 3070 kg of gold from ore averaging 9.35 g/t gold between 1987 and 1990 when the mining operation was terminated.

Jan 1, 1994

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

Jan 1, 2005

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

Jan 1, 2000

By Neill A. O, Worth I, O&apos

The formation of Kalgoorlie Consolidated Gold \lincs 1't% Ltd hati pla,xd all the major the gold producing areas adjacent to the city of Kalgoorlie/Boulder under one management, enabling the development of the 'Super Pit'. This has facilitated the economic optimisation of the resource. Optimisation has been achieved by the timely collection and presentation of data and the use of these data to reduce costs and improve planning procedures.In particular the following issues have been addressed:ò the reduction of the impact of the mining activity on the adjacent urban population centre,ò implementation of safety procedures for mining through underground voids,ò the determination of the optimum bench height and mining method for ore production benches and blast design. This system is fundamentally based on maintaining a high degree of selectivity while achieving a balance of relatively low unit operating costs,ò assessment of the comparable benefits of contractor versus owner operated earth moving equipment, andò the development of effective ore body models, production reconciliation and the long term mine planning procedures to facilitate effective strategic planning.

Jan 1, 1993

The Hishikari gold deposit, discovered by the Metal Mining Agency of Japan, has become a giant class epithermal gold deposit with the highest grade of gold yet recorded in the world through detailed exploration and development by the Sumitomo Metal Mining Co., Ltd. The exploration strategy involved a regional approach combining geological and gravity surveys over a 900 km2 area which had historically produced over 120 t of gold. These surveys were carried out to grasp the common geologic features of epithermal gold deposits in the survey area. A genetic model for epithermal gold deposits in the area under regional survey was also considered based on detailed research of the Kushikino epithermal gold deposit which was in operation at that time. This model was applied to the targeted areas, and important relationships between mineralization, host lithology, intensive propylitic alteration and gravity highs became apparent. The Hishikari block was selected in this way and bonanza gold was discovered during drilling. Since the development of the Hishikari mine, information useful for further exploration for the same type of deposit has been accumulated.

Jan 1, 1995

This paper reviews the development and operation of a small underground tin mine in NE Tasmania. Tin mineralisation was discovered in the Lottah area in the 1880's with early alluvial and eluvial workings leading to the development of large low grade open pit operations. Apart from short lived activities operations ceased in 1915. Intensive exploration in 1978-81 outlined substantial tonnages of low grade tin mineralisation (0.2% Sn) of open pit material. An underground ore body was also located (800 000 tonnes 0.6% Sn). Spectrum Resources Australia Pty Limited acquired a 98 percent interest in the property in 1988. Mine and mill development began in early 1989 based on an underground mine utilising trackless mining using room and pillar with fill stoping. The milling circuit involves primary jaw crushing, Barmac secondary crushing to lmm, Mogensen and DSM screens with jigs and tables to make a wet concentrate. Final tin concentrates are produced by high tension and magnetic separation. Planned production rates are 500 t/day with a mine life of 6-7 years.

Jan 1, 1990

By O Bøckman, E Thisted, K H. Esbensen, U Thisted

Process industry measurement systems, once installed, are often interpreted as static black boxes delivering correct values as long as not proven otherwise. After first implementation and set-up with a distinct sampling frequency, they often run ‘forever’ without checking if this frequency is still appropriate with respect to changed raw materials characteristics, different process conditions or changed customer specifications. Failure detection is based on operator experience and skills (often close to an art form) and/or from control measurements of reference samples. This may well be too late for many industrial process contexts. An appropriate sampling frequency is a critical success factor for valid monitoring and control.Based on the methodology of variographic analysis we here illustrate how to design/re-design/optimise an industrial measurement system in terms of sampling frequency, discretisation and accuracy based on customer specifications. We also show how variographics can be used to monitor for deviations. We use experience from process industry to show how these methods can be used not only for product characterisation, but also for monitoring input factors, process indicators and measurement of these. The information hidden in the vast amounts of data that is continuously created in modern process industries can be utilised to cut costs in the measurement activities and at the same time contribute to early error detection. We illustrate by case examples from production processes at a nickel refinery, supporting the Lean and Six Sigma methodology. This will provide a standard operating procedure for monitoring the stability of measurement systems, and provide a basis with which to discuss how a variographic approach can be integrated with the Lean and Six Sigma approach as an online tool to map, characterise and validate measurement systems and thus avoid more cumbersome measurement system analysis in full detail.CITATION:Thisted, E, Thisted, U, Bøckman, O and Esbensen, K H, 2017. Variographic case study for designing, monitoring and optimising industrial measurement systems – the missing link in Lean and Six Sigma, in Proceedings Eighth World Conference on Sampling and Blending , pp 359–366 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By C Donnelly

Redpath Australia is using a unique mining method for the Australian underground coal industry at Kestrel Mine Extension in the Bowen Basin, Central Queensland.The project involves completing two separate drifts from the surface for access to the German Creek Coal Seam located approximately 230 m below the existing surface. The scope of work is primarily the construction of two drifts; the first is 1577 m at 1 in 6 gradient and the second 1874 m at 1 in 8 gradient. Each drift has been developed by a Mitsui S200 roadheader with modifications to allow for a continuous tunnelling/mining cycle operation. A shotcrete boom has been fitted to the left hand side of the machine with the operators console located at ground level. Another operators console is elevated on the right hand side of the machine to allow operation of the rotary drill boom which is mounted on a slide rail to allow flexibility of positioning depending on the stage of the cycle. In support of the roadheader activities, an integrated conveyor system mounted on a sliding floor arrangement is able to be advanced as the mining face progresses. This sliding floor consists of four 1.5 m × 6 m sections that utilise hydraulic rams to ‘walk’ inbye, allowing room for installation of precast concrete floor panels for final floor completion. This method borrows from the tunnelling and construction industries to eliminate place-change delays in the mining cycle by enabling complete ground support installation without retreat of the primary development machine from the face. The aim is to reduce the project duration with the completion of final floor and services to within 30 m of the operating face as it advances.

Mar 21, 2011

By T J. Napier-Munn, T Perkins

The JK Drop Weight test was developed at the Julius Kruttschnitt Mineral Research Centre (JKMRC) in the early 1990s as a means of characterising ore for the purposes of AG/SAG mill and crusher modelling. It has since been used extensively worldwide in the minerals industry as a key ore characterisation test which produces parameters which are used in comminution circuit design and optimisation. The test generates three parameters which are used in the AG/SAG mill model of the JKSimMet software. The resistance of the ore to high energy (impact) breakage is quantified with the A and b parameters. The oreÆs resistance to low energy (abrasion) breakage is measured using the ta parameter. The accuracy and precision of the results of the JK drop weight test are of great importance given that the parameters are key inputs in the design of such capital intensive items as SAG mills. Plant optimisation exercises also rely on the accuracy of the parameters to assist with improving the performance of an existing circuit. A thorough analysis of the accuracy and precision of the parameters generated by the JK drop weight test has now been undertaken by JKTech Pty Ltd (JKTech). An experimental program was designed using statistical methods to plan a hierarchical set of 24 drop weight tests on homogeneous material. Each stage of the test was identified and incorporated into the experimental design so that the contribution to the overall error of each stage could be quantified, including the effect of operator. The data were analysed by nested analysis of variance. An overall analysis of the A, b and ta parameters generated from the test program has now quantified the variance of these parameters more thoroughly than ever before. Using the results for the impact parameters, an analysis has been carried out to investigate the effect of these variances on final SAG mill comminution circuit design. The results will also be used to refine the comparative testing procedures currently in use by licensees worldwide.

Jan 1, 2008

By Bof J, Lowe S

BHP's newest colliery on the Southern Coalfield Is Tower Colliery. It is situated near Wilton some 60 kms south west from Sydney. It commenced its operations in 1978 and since that time has experienced considerable roof problems. In its eight years of operations, production has been 936 687 tonnes to December 1985. To a certain extent this is a reflection of the ground control r,,b1cros present in the colliery. paper out Iines the signif mt g,, logical features that are known to exist in the colliery and their influence on roadway development. Faulting has hindered the mine's development and an igneous intrusion has had outhursting associated with it. The prevailing roof rock has also had an impact on the roadway conditions. The paper will look at intersection deformation in present workings. Extensometers have been installed in these areas and provide measurements to verify visual observations. The results show a significant increase in roof movement as the roadway is developed from a single heading, to a T-intersection and then Into a four-way intersection.

Jan 1, 1986