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By K White, C Ferguson, M Harding

Understanding watercourses and river processes at a landscape scale is vital for managing risk to mining infrastructure and operations as well as minimising future environmental impacts beyond the life of the mine. Recognising this, Iluka Resources Limited engaged Alluvium Consulting Australia to identify and characterise watercourses across several neighbouring mineral tenements in the Eucla Basin, South Australia (Alluvium, 2013, 2014a, 2014b). The objective of the studies was to inform planning for risk management during mine planning and operation and appropriate landscape rehabilitation for mine closure.Mining operations in the area are by open cut extraction of mineral sands. The extracted resource is processed on-site before leaving the site for export. Several pits are to be developed in stages with simultaneous backfilling and surface reinstatement. Mining is initially taking place in the Jacinth tenement, where up to 100 km of watercourses may be directly or indirectly impacted (refer to Figure 1).The total study area (shown in Figure 1) is approximately 330 km2 and spans three smaller areas that were the focus of separate investigations during mine planning.CITATION:Ferguson, C, White, K, Harding, M and Hardie, R, 2016. Landscape-scale assessment of watercourses in remote arid South Australia to inform mine planning to mine closure, in Proceedings Life-of-Mine 2016 Conference, pp 200–204 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By M Burdick, A Harding, M Krulc, M Chappell

Substantial schedule advantages can be made on projects if cross-passage construction can occur at the same time as tunnel boring machine (TBM) operation with little or no impact on TBM logistics. However, this approach can prove difficult to achieve with many of the more cost-effective means of supporting the segmental lining during cross-passage break-out. This paper discusses the constraints and shortcomings of conventional approaches, and describes how a cost-effective solution involving a shotcrete shell and opening constructed inside the segmental lining was designed and constructed to deliver cost and time savings on Seattle University Link contract U220.The paper explains the spatial and schedule constraints on the TBM tunnelling and cross-passage construction, and how a shotcrete solution was arrived at in preference to traditional approaches. As the solution was novel the design had to be robust, and the paper explains how this was achieved through a combination of 3D finite element modelling and closed form solutions. Following a description of the trials to verify that the structure could be demolished post-cross-passage completion, the paper describes how the shell solution was constructed, used and demolished safely to leave the lining surface in a clean and undamaged state fit for tunnel operation.CITATION:Harding, A, Chappell, M, Burdick, M and Krulc, M, 2014. Opening supports to segmental linings – a novel shotcrete support solution, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 267–274 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By M Bellamy

The DeGrussa copper deposit was discovered by Sandfire Resources in April 2009. Construction of the 1.6 Mt/a concentrator, open pit and underground mining operations commenced in March 2011 with first concentrate production achieved in October 2012. Over the next ten years, DeGrussa grew to include both the DeGrussa and Monty underground mines, establishing itself as one of the world’s premier copper producers with total production of 663 000 t of contained copper by the time the mine closed. Final ore was trucked from Degrussa on 5 October 2022. This paper examines the mine closure experience from both a planning and operational perspective. The paper provides an overview of the site’s mine planning process including the factors involved in determining the end of the mine life and how this was tracked and communicated in the lead up to the end of mining operations. It will also look at some of the specific operational aspects involved in maintaining steady state production all the way through to the last day while facing increasingly challenging conditions. These factors, along with the external factors faced by most of the industry such as labour shortages and COVID related disruptions, contributed to making it an interesting journey to the end of operations at DeGrussa.

Mar 29, 2023

By A Maier, M Goldner, C Gimber

Given the ongoing global crises of climate change and nature loss, with the World Economic Forum (WEF) identifying them as the top risks to global economies in terms of both likelihood and impact in the coming ten years (WEF, 2022), there is increasing, pressing demand for companies to demonstrate they understand their climate and nature related risks and look toward contributing genuine beneficial environmental outcomes. Within the mining industry, mine closure is the obvious field in which climate and nature positive strategy can be linked with operations. To do so, there is a need to challenge long-held assumptions around closure in the mining and regulatory context; particularly, to shift the focus from closing individual mines to considering regional opportunity generation and value creation.

Aug 2, 2023

By S Nie, I Bergqvist, F Ouchterlony

In blasting, a few or many cracks are driven from the borehole into the rock. But what causes the cracks? The most common theory of breakage consists of two stages; first the shock wave causes radial cracks to form around the hole then the gases penetrate into the cracks, and widen them and make them longer. Another theory presented by Brinkmann suggests that the back damage is primarily controlled by shock and that the gas penetration is the mechanism controlling breakout of the burden. He did his experimental work using blasthole liners. Recent research at SveBeFo has examined this matter further. In a quarry a number of benching holes have been blasted simultaneously. In some of these holes tubular Swellex bolts were inflated and decoupled charges put inside the tubes without stemming. Other holes were identically charged but without the lining. Finally some holes were also stemmed. After blasting the cracks in the remaining rock were studied. There was no difference in crack lengths between holes charged normally (no stemming) and holes where the charges were inside the bolts. On the other hand when stemming was used, the crack lengths increased for some explosives but remained the same for an emulsion explosive. In another set up blasted granite blocks were charged in the same way as above. Then we could also measure the bore hole pressure. The pressure gauge consists of a small carbon resistor inside a steel cylinder. It is called LHM (Location-fixed Hydrodynamic Measuring Cup) and is placed at the bottom of the hole. A smaller exit hole from the bottom is drilled for the cables. The paper presents the technique and the results obtained from both the quarry blasting and the blasting of the blocks.

Jan 1, 2001

By G McCullough, B Mutsaers, J Jessop

"*This is an abstract only* Geometallurgical initiatives have demonstrated considerable value to operations that have trialled them. However, it is extremely difficult for these initiatives to become properly embedded into the operations and for that value to be realised on an ongoing basis.This paper will explore some of the historical reasons why this is the case. Some of these reasons include the limited tools available to manage an integrated operation. These, in turn, have resulted from poor communications infrastructure, inadequate sensor capability and the way technical mining software has evolved over the last 30 years.This paper will then investigate how the evolution of technology in recent years can help overcome these constraints and compare progress with similar industries.CITATION:McCullough, G, Mutsaers, B and Jessop, J, 2013. Obstacles to embedding geometallurgy decision-making into operations and how to increase maturity of this critical capability, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013, pp 139-140 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 29, 2013

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 K T. Mandisodza, T J. Cartledge

The principal objective of Geotechnical Engineers supporting operating mines is to provide safe working conditions and ensure that pit designs are geotechnically optimised to site conditions and pre-defined stability requirements. Pit slope designs are delivered in advance of pit excavations. Making changes to these designs is usually slow to enact and involves a layered sign-off before implementation, leading to unwanted delays in their adoption and subsequently increased production pressures. When unexpected ground conditions are encountered during the mining process, or short-term mining schedule requirements demand it, changes to these designs may not be easily feasible in certain situations. It is when these scenarios arise that Geotechnical Engineers need to be proactive and consider unconventional options to deliver safe operating conditions while satisfying short-term requirements to the mine schedule. Essentially, the geotechnical short-term strategic designs double-pronged approach supports the mine schedule while providing safe conditions and minimising geotechnical risks for people and equipment. Common short-term strategic geotechnical designs include; slope buttressing, over-steepening cut slopes to increase reserve recovery through unplanned or emergency cutbacks, and accepting risk threat and operating under unstable slopes. When implementing strategic design options, the Geotechnical Engineer must consider the broader implications for such designs. They must think of the plan’s long-term effects on the mine schedule and pit wall stability. Initiating aggressive designs to recover additional reserves to satisfy a short-term scheduling demand could result in-pit wall instability or suboptimal pit layout. Before and during the implementation phase, the Geotechnical Engineer must communicate and engage with relevant stakeholders to ensure that the plan is executed accordingly and geotechnical risks are effectively managed. Proactiveness to ground response and implementation of risk management strategies will improve safety performance and optimise mining schedules.

Jun 22, 2022

Large deposits present computational challenges to todayÆs commercial orebody modelling systems that are based on conventional block models. We describe a system that is specifically engineered to model and visualise large deposits. Central to the system is linear octree encoding of conventional block models and real-time conversion of three-dimensional (3D) meshes to linear octrees. We provide both methodological treatment and practical experience in implementing such a system. A commercial implementation is also presented to demonstrate the validity of the approach.

Sep 26, 2011

By D Felipe, G J. Harbort

In the past 40 years substantial changes have occurred in flotation machines. This has included increases in mechanical cell size to 630 m3 , significant changes to flotation column aeration design and widespread use of the Jameson cell and other pneumatic flotation cells. Over the corresponding period there has been increased used of machine characterisation measurements to benchmark and optimise flotation circuit performance. JKTech maintains a database of industrial flotation machine characterisation measurements. The database contains over 4000 entries and includes gas dispersion measurements, such as bubble size, gas hold-up and superficial gas velocity, cell dimensions and impeller tip speeds. Data comes from numerous operating sites and commodity groups, including gold, copper, molybdenum, nickel, palladium, lead-zinc, platinum, silica, phosphate, coal and iron ore. Flotation duties registered include flash flotation, preflotation, roughing, scavenging and cleaner circuits. Measurements have been conducted on a wide range of flotation machines from different manufacturers. This includes forced air machines, such as Outotec and Dorr Oliver, and self-aerated machines, such as Denver and Wemco. The database also includes substantial flotation column entries, such as the Microcel, Eriez/CMT Slamjet and Jameson cell. This paper describes the flotation machine characterisation database and discusses the variation between different types of industrial flotation machines, in operating production circuits.

Aug 24, 2022

By W Assibey-Bonsu

The paper provides a brief review of the multivariate uniform conditioning and the localised multivariate uniform conditioning techniques and presents a case study based on a porphyry copper gold deposit in Peru. Two other important scenarios have been investigated and will be particularly emphasised: The recovered selective mining unit (SMU)s depend on a combination of copper and gold content, which can be expressed by means of ænet smelter returnsÆ (NSR). Two approaches are compared. Firstly, the application of a composite cut-off on NSR on the joint distribution of each grade and the application of uniform conditioning to three variables is investigated, ie for the first approach NSR is used as the main variable. The second approach considers copper as the main variable. In the case of multiple domains the procedure used to apply the technique to process mixed panels is clarified and recommendations are made.

Sep 26, 2011

By M Chen, Q D. Gao, Y G. Hu, P Yan, W B. Lu

The safety and stability of construction structures are often affected by blast-induced waves. Investigating the generation mechanism of shear wave (S-wave) during blasting is important, because it has a strong effect in blasting damage. In this paper the generation mechanism and verification of S-wave was studied analytically and numerically. Under the finite velocity of detonation (VOD) of cylindrical charge or the compression wave (P-wave) communicating with the interface of different media during the propagation, the generation mechanism of S-wave was analysed. Propagation of blasting wave in cylindrical charge was simulated with the elastic model, and the generation of S-wave induced by finite VOD was proved. To compare with different numerical methods in simulating the generation of S-wave, the blasting process of instantaneous detonation was simulated by using the elastic model, elastic-plastic model and smoothed particle hydrodynamics and finite element method (SPH-FEM) coupled model. Results demonstrate that the S-wave could not be found in middle section of the charge if the elastic model is employed. But when using elastic-plastic model and SPH-FEM coupled model, the generation of S-wave could be verified. Under the SPH-FEM condition, the amplitude of S-wave is larger and the arrival time difference between P-wave and S-wave is closer to theoretical results.CITATION:Gao, Q D, Lu, W B, Hu, Y G, Chen, M and Yan, P, 2015. Comparison of the generation of shear wave with different simulation approaches, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 79–88 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By S P. Young, K R. Monro

Reducing metal prices have forced mining operations to become more efficient and innovate in order to do more with the existing base. Much of this effort has focused on improving the efficiency of load and haul operations. The key to this is to understand and quantify where delays and missed opportunities exist. Metrics such as utilisation of availability, efficiency utilisation and asset availability are helpful indicators of performance; however, uptime-based time usage models and performance analysis tools using productive operating time models help to identify additional improvement opportunities.Phu Kham is a copper-gold mine operated in the Lao People’s Democratic Republic (Laos) since 2008 by PanAust Limited. The mine is a single large open pit of 450 m depth, running a fleet of 51 100 t class rigid dump trucks and 300 t and 200 t shovels controlled with the aid of a fleet management system in order to achieve ex-pit material movements of 56 Mt/a.Commencing in late 2014, a range of initiatives were implemented in order to improve the efficiency of the mine haulage fleet. These include hot seating of all operator changeouts via changeout ramps, split shifting of crews to minimise queuing delays, maximising blast volumes and minimising blast event days to reduce blast exclusion delay events including opportune refuelling of equipment during blasting events, inspections of trucks during refuelling events, implementation of a dedicated haul road services team to help reduce wet weather related delays and infrastructure development for haul path efficiency improvements.These and other initiatives have allowed the mine haulage fleet utilisation of availability (UofA) to be sustainably increased from 85 per cent to 97 per cent (see Figure 1), efficiency utilisation to increase from 85 per cent to 90 per cent, and productive operating time (POT) to increase from 73 per cent to 84 per cent. The corresponding increases in efficiency of the haulage fleet has allowed an equivalent reduction of eight haul trucks from the fleet to meet continuing life-of-mine production requirements.CITATION:Monro, K R and Young, S P, 2016. Truck haulage improvements at the Phu Kham mine – the journey to 97 per cent utilisation of availability, in Proceedings International Mine Management Conference, pp 339-346 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 22, 2016

By J Maxlow, M J. Woods, M P. Sandy

The Newcrest Mining Limited Telfer operation comprises both open pit and underground operations producing gold and copper. The underground operation is made up of three production areas, the sublevel cave (SLC), M Reefs narrow vein open stoping and Western longhole open stoping areas. With stoping situated on the abutments of a mature and active sublevel cave, the interaction between mining areas is often complex. This is particularly evident in the M Reefs orebodies with high levels of extraction in all four reefs, and reliance on pillars to maintain local and global stability. A key concern was the potential for a cascading pillar failure to develop and rapidly progress through the M Reefs stoping area. The monitoring plan needed to capture any change in overall stability and identify if deformation was caused by pillar failure within the M Reefs and hanging wall closure, or shear on the reefs caused by SLC influence.

Nov 29, 2022

By D J. Logan, J Jackson

"As of 1 December 2014, the 2012 edition of the JORC Code requires Ore Reserves to be defined by studies at the pre-feasibility or feasibility level. This paper examines how the pathway for most mining developments is determined in the Pre-Feasibility Study and how a trade-off must be made between the need to make the best decision, the constraints of limited time and resources, and the level of the project’s accuracy and uncertainty in terms of value. Issues considered include framing the scope of the study, planning for robust decision-making and ensuring effective communication between the diverse disciplines within the team.An inherent conflict exists between the immediate value added to a mining business from an increase in ore reserves resulting from a ‘quick’ Pre-Feasibility Study and the long-term value of pursuing a development strategy based on proper investigation and evaluation of the options. Recognition and resolution of this conflict is necessary if a project is to progress into future development stages, both in a timely manner and with the optimal development alternative and strategy.The challenge for project developers and those conducting the Pre-Feasibility Study is to understand what the key deliverables are (ie an Ore Reserve statement, option selection, business evaluation, forward work plan or risks) and how to follow good practice to ensure that these deliver value.CITATION:Logan, D J and Jackson, J, 2016. The pre-feasibility study – big choices, little time, in Proceedings Project Evaluation 2016, pp 122–132 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 8, 2016

By Smith I. K

A Data Acquisition System with a capacity to monitor 2000 analog instruments has been installed at the mines operated by the Zinc Lorporation, Limited and New broken hill Consolidated Limited (ZC/LVbHC), New South Wales, Australia. Since commissioning in March, 1982, the system has proved its value in providing up-to-date information to both Rock Mechanics and Mining personnel. The paper describes the function of the major software and hardware components of the system, and identifies the advantages that an on-line monitoring system provides in the day-to-day operation of a large underground mine.

Jan 1, 1983

By D Olwagen, C Stanton, J Gerber

From December 2013 to February 2014 the Southern Middleback Ranges magnetite concentrator went through a successful optimisation process that included the installation of extra grinding power to treat a wider range of ore types. After the initial improvements, sampling surveys were conducted to identify the mineral deportment through the concentrator. Samples collected during the survey were analysed using X-ray fluorescence, quantitative X-ray diffraction and QEMSCAN™ to cross-validate the analysis. Certain streams were also put through a laboratory-scale Davis Tube Recovery washing process to produce clean concentrates for analysis. The QEMSCAN™ analysis identified various metallurgical characteristics (mineral association, particle sizes, grain sizes, particle densities, etc) and these were evaluated for each separation and comminution stage to both understand the processes involved and identify opportunities for improvement. Key findings from the investigation indicated the importance of understanding the elemental deportment of target elements throughout the various minerals. The standard practice of tracking iron deportment through assay provided misleading results on losses to tail through the plant. The investigation provided insight into both wanted and unwanted minerals and the efficiency of each separation stage. The efficiencies of separation are critical due to their impact on downstream capacity, and the investigation provided insight into where opportunities exist to extract more benefit. The findings of the geometallurgical analysis have been implemented on the concentrator, and improvements in the rejection of non-magnetic minerals have been seen.CITATION:Gerber, J, Stanton, C and Olwagen, D, 2015. Using geometallurgy during process optimisation activities at the Southern Middleback Ranges magnetite concentrator, in Proceedings Iron Ore 2015, pp 561–566 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By Carrucan M. J

Costain Resources Limited operates two open cut coal mines in the Hunter Valley coalfields of New South Wales, Ravensworth Mine and Warkworth Mine. The location of the Ravensworth operation is shown in Figure 1. In the case of the Ravensworth Mine, Costain Australia is essentially a contract miner and is contracted to supply coal to Pacific Power (previously The Electricity Commission of New South Wales), on contracts won through a tender system. Due to the existing infrastructure and the lease area that associated with the contract, the mining strips at Ravensworth South have a maximum strike length of 1500 metres. This paper deals with the methods of scheduling used to overcome the challenge of mining the short strike length, multi-seam deposit at Ravensworth South.

Jan 1, 1992

In the Illawarra District of New South Wales, Mines were traditionally developed from the seabord. The advantages were close access to the working faces and a minimal depth of cover. Travelling times to the working faces have become prohibitive in many cases due to progressive westward development of the mines. As a result, additional vent- ilation shafts were sunk to service existing mines and new mines were established west of the Illawarra escarpment. Mining operations west of the escarpment are now being conducted at an increasing depth of cover and can be effected by gas related problems such as high seam gas emission rates and gas outbursts.

Jan 1, 1983

The progress of longhole open stoping (LHOS) at The Zinc Corporation, Limited and New Broken Hill Consolidated Limited (ZC/NBHC) is described. The design of a novel sloped wall longhole stoping method at NBHC which should allow the cuplete extraction of the orebody without the formation of pillars and with minimal dilution of the ore with sandfill is reviewed.

Jan 1, 1983