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By D Piason

Newstan Mine commenced mining operations in 1887 and has since undertaken extensive mining within the Young Wallsend, Great Northern, Fassifern, Borehole and West Borehole coal seams using a range of mining methods including board and pillar mining and longwall mining.Newstan Mine is planning to extend the existing mine workings using longwall and miniwall mining methods to produce up to 4.5 Mt/a of run-of-mine (ROM) coal for at least 25 years. The planned extension in the Main East and South West sections will involve developing new longwall panels and related mains headings. The new area contains higher specific gas emissions (SGE) than previously experienced at Newstan Mine. To achieve the optimum ventilation requirements for the longwall operation in this new area, a new ventilation shaft was designed to be constructed using the blind boring method in the South West Headings section.This paper presents the shaft design parameters and selection criteria for the construction of the new ventilation shaft, including the construction phase and the holing process to connect the shaft to the underground workings. The paper also discusses future ventilation requirements for Newstan Mine.CITATION:Piason, D, 2015. South-west ventilation shaft project at Newstan Mine, in Proceedings The Australian Mine Ventilation Conference, pp 229–238 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

Detailed underground mine design and optimisation studies undertaken by the author over the past few years have clearly demonstrated that additional value can be created by varying the cut-off grade (COG) spatially throughout a deposit as well as over time. This additional value can be particularly significant for marginal operations. This paper, by way of worked examples, illustrates the conceptual and practical considerations of applying a differential cut-off policy for an underground mine to both maximise value and manage risks associated with production and metal price volatility. Consideration is given to both the design stage of a new mine and to the strategic and practical application of a differential cut-off policy in an operating mine.

Jan 1, 2005

By B Chapman, B Gaida, L Drowley

The 372 MW Ulu Jelai Hydroelectric Project is a peaking power scheme located in the Cameron Highlands, Malaysia. The main features of the project include an 84 m high roller compacted concrete dam; two weirs which divert flows from adjacent catchments via transfer tunnels into the main reservoir; an underground power waterway; and an underground power station complex comprising three large caverns with connecting tunnels approximately 240 m below surface level. The project includes approximately 25 km of tunnels excavated in fresh granite rock mass with some distinct shear zones of weaker material. The majority of the tunnels are being excavated using drill and blast, with the two transfer tunnels being excavated with a tunnel boring machine (TBM).This paper focuses on the design and construction of the Telanok underground power station complex and also some aspects of the design for the headrace tunnel. Topics covered include geological site investigations including in situ measurements of rock stresses; development of a geological model and parameters for rock support design; three-dimensional modelling to assess interactions between the caverns to optimise rock support; design of a rock anchored crane beam; construction of the caverns and design of the unlined headrace tunnel taking into account hydraulic jacking and operational pressure fluctuations.CITATION:Drowley, L, Gaida, B and Chapman, B, 2014. Design and construction of large caverns in granite – Ulu Jelai Hydroelectric Project, Malaysia, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 361–368 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By Y Li, D J. Williams, E Topal

A mine waste rock dump does not have any intrinsic value, yet is an inevitable structure in surface mining operations. Since the purpose of mining is to maximise profit, possible expenditure reduction in hauling waste rock to the dump, which can represent up to 50 per cent of the total operating cost, is highly desirable. Apart from cost, potential acid mine drainage (AMD), due to seepage from surface waste rock dumps containing reactive waste rock, could threaten the ecological balance, drinking water supplies and irrigation systems downstream from a mine site. In order to minimise these potential risks, selective placement of benign and reactive waste rock, and the encapsulation of reactive waste rock by benign waste rock, need to be carried out during the construction of the rock dump.In this paper, a new methodology, based on mixed integer programming (MIP) is developed to manage waste rock dumping. The model aims to minimise waste rock haulage costs by locating the optimum destination(s) for each waste rock block, while at the same time controlling the placement of reactive waste rock to minimise the potential for AMD. Tests on small-scale virtual data demonstrated that the model is capable of dealing with selective placement of different waste rock types, encapsulating reactive, potentially acid forming (PAF) waste rock, and stockpiling benign waste rock for encapsulation and rehabilitation purposes. The solution time for the MIP model is far less than the traditional manual approach, and the resulting schedule is up to 46 per cent more cost effective.CITATION:Li, Y, Topal, E and Williams, D J, 2012. Mathematical approach for better mine waste rock dumping management, in Proceedings Life-of-Mine 2012 , pp 207-214 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By R Winterberg

Concrete is a well established and reliable construction material for the permanent lining of tunnels, but shows some weak performance characteristics, which can be overcome by the addition of specialised fibre reinforcement. This paper addresses the particular performance design requirements of segmental linings, discussing the improvements of fi bres on concrete properties. Focus is made on the beneficial effects of fibre reinforcement on the cracking behaviour and the toughness performance, providing a safe and durable tunnel lining.Not only the mechanical performance of fibre reinforced concrete (FRC) for segmental linings, but also the durability of the linings has gained growing attention among the designers and consultants. Especially tunnel linings with exposure to media with corrosion potential, such as wastewater sewer tunnels or desalination plant outfall tunnels, have high requirements on their durability. The design of these structures must provide a comprehensive study of durability aspects. Fibre reinforcement can substantially improve the durability of concrete.Research has been carried out on the cracking behaviour of concrete. The beneficial effects of steel fibres on the cracking behaviour reduce the permeability by reducing the flow paths within the concrete. Crack bridging steel fibres create necking effects in bending cracks, leading to earlier closure of the cracks. Further, steel fibres create particular crack formations, which lead to a substantial reduction of the fl ow rates through separation cracks. The results also show that considerable cost savings can be achieved using FRC, as the thickness of the linings can be reduced.The durability design issues will be addressed and underlined by a case history on the Hobson Bay sewer tunnel in Auckland, New Zealand.

Mar 8, 2011

It is a common misconception that the grant of mining tenure, whether it be an Exploration Permit, Mineral Development Licence or Mining Lease, will entitle the holder to access all land within it in order to explore or mine. The ability for miners to access their tenure in order to undertake activities is critical to the industry. While significant time and energy is quite rightly dedicated to resolving native title and cultural heritage issues before the commencement of mining operations, the same cannot always be said for addressing potential impediments that arise as a result of the overlap between mining and other tenures. Miners should be aware of the overlaps that occur with other tenure and the impact of these overlaps on the minerÆs ability to explore or produce from the area. The existence of an overlap with petroleum tenure, nature refuges, national parks, wild river areas or reserves such as aboriginal land leases are all likely to have an impact on the minerÆs ability to access the area and conduct activities. In some instances, such as an overlap with petroleum tenure, Queensland legislation encourages the miner to reach agreement with the holders of the overlapping tenure. However, in other instances, such as an overlap with a national park, mining tenure is unlikely to be granted at all. This paper summarises the impacts and impediments that arise as a result of overlaps of tenure that are likely to affect mining operations. It also provides examples of how these impediments can, if possible, be overcome under Queensland legislation.

Jan 1, 2007

By C Artica

Two quantitative methods for Mineral Resource classification have been applied to a copper skarn deposit beneath a large open pit that is mining a world-class porphyry complex. A drill hole spacing study (DHSS) using the single block kriging method (SBK) and a conditional simulation method (CS) were applied to the skarn deposit and the results compared. Inputs to both processes included the proposed mining rate and stope designs to estimate the likelihood of achieving grade and metal production targets. Mineral Resource classification of the deposit considers the relative precision of tons, grade and metal predictions over quarterly and annual production periods. These relative precision estimates are calculated at 90 per cent confidence interval (CI). The SBK method represented the production period as a single large block. Kriging estimates were performed in the large block for various synthetic drill hole grids, and the estimation errors derived. The error was assumed to be normally distributed due to the large block size and quantity of samples, allowing CIs to be deduced. The CS method followed a conventional sequential Gaussian simulation workflow where grades were simulated with a 5 ft × 5 ft × 5 ft grid node spacing inside mineralisation domains. Each realisation was then averaged up to monthly production volumes represented by a combination of designed stopes, and the coefficient of variation (CV) for the averaged grade was calculated. CI on the relative precision of grade predictions were then deduced from the CVs. The two methods produced similar results; despite being calculated independently. CS results were used to report uncertainty in the proposed life-of-mine plan and highlight areas for additional drilling. SBK results were used as the basis for Mineral Resource classification as this method has been previously applied to the skarn deposit.

May 24, 2023

By D J. Brake

Faced with the need to improve workplace conditions in both its development and production headings in its existing K1 orebody, as well as its new K Link and K2 orebodies, the Kencana mine in Indonesia took the novel approach of reversing the ventilation on most of its access ramp by outcasting up the ramp to the portal. Working levels were then fed with fresh air via auxiliary fans sealed into the current surface ‘egress’ intake raises (ladderways) or another small surface intake raisebore rather than from fans hung in the ramp as in the past. Outcasting the portal provided a substantial increase in the total mine exhaust capacity allowing fewer levels to be ventilated in series and significantly improving conditions, especially in the most difficult workplaces to ventilate. It also reduced the consequences if there was to be a fire on a vehicle in the ramp. The same system using the ramp as an exhaust is also intended to be used as part of the final ventilation solution for the new K2 orebody which also uses a novel single surface ventilation shaft that is vertically split into separate intake and exhaust compartments using a concrete brattice. Using the main ramp as an exhaust has potential application in many other operations in Australia using surface ramps which otherwise frequently suffer from overuse of series ventilation circuits and poor working conditions at the mine bottom.

Mar 21, 2011

By A Riles

"Three issues of relevance in a modern tailings storage facility (TSF) are:geotechnical stabilitymanaging acid rock drainage (ARD) from pyritic tailingsmanaging the tailings from cyanidation of gold ores. Drawing on examples from both copper porphyry flotation and sulfide-hosted gold ores, this paper demonstrates that giving some weight and importance to the process tails properties upfront can influence the flow sheet and not only improve tailings management effectiveness but also impact positively on economics. In the case of a typical copper porphyry ore with moderate pyrite content, the rougher tail in a conventional high pH selective flotation step is usually classified as potentially acid generating (PAG). To avoid the generation of ARD within the tailings and the requirement for a costly plastic lining, subaqueous deposition is recommended, which in turn has negative implications for tailings stability, consolidation and closure. Adopting a neutral pH rougher stage rejects silicate gangue but recovers pyritic material to the cleaners for a subsequent selective flotation stage, often after regrinding. This effectively quarantines the PAG pyritic material in a much lower volume cleaner tail, which can then be appropriately encapsulated within a larger non-lined flotation tails facility. It also facilitates cyanide leaching of the cleaner tail for gold recovery, with the encapsulated tailings facility being suitable for cyanidation tails storage. A case study from Europe is examined. For gold ores where the gold is sulfide-hosted, but not refractory, a flotation route with cyanidation of the concentrate can similarly produce the majority of tailings as a benign flotation tail and again quarantine the low volume concentrate leach tail in a small encapsulated cell with appropriate residual cyanide management measures applied. Overall economics for intensive leaching of a low volume concentrate stream can also be surprisingly positive. A feasibility study design example of the process and TSF is presented. CITATION: Riles, A, 2016. An Integrated Approach to Optimising All Concentrator Products, Including Tailings, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 341–346 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By H S. Pescini

A material aim when feeding ore blends into a processing facility is to reduce the variability of the properties of the feed material and to maximise the output, or throughput. At the Mining Geology conference of 2019, we presented a paper on optimal blending of coking coal given geological variability. The paper introduced integer-programming techniques to both maximise value and minimise feed or product variability. We discussed an application where the geological uncertainty is characterised using a normal distribution and exact solutions are readily obtainable using second order conic constraints in the mathematical model. Geological uncertainty is not always normally distributed, many properties will be characterised as log normal or some other skewed distribution. For example, copper can be some form of lognormal and Fe in Iron ore has a left skewed distribution. In this paper, we discuss some distribution free techniques to optimise the blends of plant feed or output given a quantified geological uncertainty. We discuss the sample average approximation method and how to set-up and apply the method to an ore blending problem. Evaluating a case study demonstrates that the explicit use of non-normally distributed geological uncertainty can better optimise feed into an ore processing facility and potentially add significant value. The approach is equally applicable to all mining and processing operations that blend material into a processing facility or directly into a saleable product.

Mar 22, 2022

By P Dowd, A Adeli, C Xu, X Emery

Geometallurgical modelling is increasingly being incorporated into mineral resource modelling and estimation as a means of increasing efficiency, decreasing operating costs and reducing risk in mining operations. Traditional geostatistical workflows for geometallurgical modelling face several difficulties, in particular, related to the non-additivity of process response variables, to highly heterotopic data sets and/or to preferential sampling designs, all of which may explain why most attempts to estimate geometallurgical response variables from assay data and mineralogy are still based on statistics and machine learning. The aim of the work presented here is to demonstrate the applicability of geostatistics to estimate copper recovery from copper sulfide ores at the Prominent Hill Iron Oxide Copper-Gold (IOCG) deposit in Australia. As recovery is non-additive, the preferred workflow is the joint estimation of the masses of metal in the feed and in the concentrate, both of which are additive variables. While the mass of metal in the feed can be estimated from abundant online assay analyses, the mass of metal in the concentrate can only be estimated from a very limited number of laboratory-scale batch flotation tests. Traditional approaches to estimating the masses of metal in the feed and in the concentrate, such as simple and ordinary co-kriging, are described and discussed. A modified version of co-kriging is introduced, which incorporates linear relationships between the mean values of the input variables, in addition to a spatial correlation model. Co-kriging with related means is shown to outperform traditional simple and ordinary co-kriging in terms of precision, accuracy and consistency of the estimates, and offers a practical and efficient tool to deal with highly heterotopic and preferential sampling designs.

May 24, 2023

By D Hume

During 2001 the Ridgeway Gold Mine, driven by company initiatives and recent NSW legislation (General Rule 2000), developed and implemented Major Hazard Management Plans to control significant hazards identified at the underground mine. The paper presents the objectives, issues, outcomes and process involved in the development and implementation of the plans at Ridgeway. The sharing of the experience gained and an overview of the intended way forward will offer a valuable insight for other mines considering embarking on a similar journey.

Jan 1, 2002

By G Britton, P Moynagh

As more than a few mines gradually sink under the weight of emails, whiteboards, notice boards and ever more complex spreadsheets, the holy grail of effective short-term interval planning and control in underground mines is as far away as ever. Despite the mining industry investing ever greater amounts in planning and Enterprise Resource Planning systems, short-term plans become ever more complex and rigid. What the industry desperately needs are not more ‘disembodied voices down the speaking tubes’, but flexible and effective planning systems that encourage people to make reasonable commitments to each other so that everyone can work as a coordinated team to complete the work required each shift.One solution to the challenge has emerged. This paper describes the ‘Fewzion’ shift planning and short interval control system which has been developed at Anglo American’s Moranbah North and Glencore’s Oaky Creek coalmines in Central Queensland. Fewzion has drawn on management theory embodied in Management Operating Systems, Lean and Theory of Constraints approaches to continuous improvement to play a key role in both mines achieving record breaking tonnages.In addition to explaining the Fewzion approach, a case study is presented describing how Anglo American’s Moranbah North improved production by 39 per cent in 2014/2015 and won ‘Coalmine of the Year’ two out of the last four years and how Glencore’s Oaky Creek sustainably improved monthly development meters by 34 per cent within two months of implementing Fewzion.CITATION:Moynagh, P and Britton, G, 2017. How a frontline planning and commitment system improves trust, commitment and results in operations, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 235–240 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017

BHP Billiton Olympic Dam produces copper cathode, uranium oxide concentrate and refined gold and silver. The operation is comprised of an underground Mine and Processing Plant and is located 560 km north of Adelaide. Water for the operation is sourced from two wellfields located 120 and 200 km from the operation in the Great Artesian Basin (GAB) at a rate of approximately 36 ML/d. Regulatory drawdown limits were established to protect regional GAB springs and are monitored at compliance bores. Drawdown was predicted in the æOlympic Dam Environmental Impact StudyÆ (Kinhill, 1997); however, pumping at higher volumes may have the potential for increased drawdown resulting in a trend towards the compliance limits. In recent years increased usage of water in the Concentrator and Hydromet sections of the Processing Plant has caused excess process water reporting to the Tailings Retention System (TRS). This has resulted in excessive amounts of liquor ponding on the tailings cells with a potential impact being contamination due to seepage of liquor to groundwater. Effective management of water by the operation is necessary to both reduce GAB drawdown and reduce the amount of liquor on the tailings cells. A site working-group has been established to investigate and pursue opportunities to improve the water use efficiency of the operation. This paper will highlight the issue of water management at Olympic Dam and discuss the various options currently being investigated to improve management of this important resource.

Jan 1, 2006

By J J. Grobler

The George Fisher Underground Mine at Mount Isa applies the long hole open stoping methodology. During the reconciliation process of transverse stopes in the George Fisher North mine it was identified that excessive underbreak was regularly experienced, with the major contribution coming from the toe area inside the stope.While over break and the resultant dilution was well investigated and well understood, limited work was done on underbreak improvement. It was decided that a re-engineering process would be followed in an attempt to improve results. The prevailing stoping practices were scrutinised and the possible causes were listed.Some of the identified causes were design, drilling accuracy, equipment condition, mucking practices and direction of firing. It was identified that in most instances the underbreak was initiated in the slot area of the stope during the first firings. Once this happened, it was impossible to get good recoveries on the rest of the stope. The slot area was carefully scrutinised and the blasting practices were changed individually.During the following two years several different strategies were trialled to increase the toe recoveries. The results indicated an overall improvement of six per cent reduction in underbreak on average, by ensuring drilling accuracy and changing the direction of firing. The economic significance of these results outweighed the time and additional work load expended to establish the cause of the problem. This paper outlines the continuous improvement process undertaken to identify and rectify the major contributing factors to the problem. It also presents a set of recommendations to be followed in order to achieve positive results.

Mar 21, 2011

By C Smith, J Cilliers, K Hadler

Unstable flotation froths, that burst before they overflow, produce no concentrate. Increasing the froth stability to improve recovery is therefore an obvious control strategy. Froth stability can be measured readily as the fraction of air entering the flotation cell that overflows as froth, rather than bursting on the surface; the ‘air recovery.’ Air rate is one of the most significant variables affecting froth stability. It is interesting that froth stability (air recovery) is maximised at a specific air rate, above or below which it decreases. It is important for metallurgists to realise that this maximum froth stability also produces the maximum mineral recovery, without compromising concentrate grade. Flotation cells must be operated at the air rate that produces the highest air recovery. The peak air recovery (PAR) to maximum mineral recovery relationship was first demonstrated by Hadler and Cilliers in 2009. Since then, the relationship between PAR and flotation performance has been widely explored; varying air rate, froth depth and particle size. Industrially, reducing the flotation bank air rate to achieve PAR yielded better mineral recoveries than other down-the-bank air rate profiles. In this paper, we present an overview of these key developments and findings in flotation optimisation based on PAR. Furthermore, using new industrial data, we show that PAR is not just applicable to rougher-scavenger cells, but also to flotation columns. Finally, we consider the future application of such an optimising control concept. CITATION:Smith, C, Hadler, K and Cilliers, J, 2018. Flotation control using froth stability: past, present and future, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 441–454 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By J Bolen, I Cameron, M Huerta, M Okrutny, K O’Leary

As greater amounts of fine iron ore concentrates enter the marketplace, new investments in iron ore pelletising capacity are inevitable to deliver these concentrates to steel industry consumers. When investors assess the two well-proven pelletising technologies, the straight grate and grate-kiln, the most appropriate choice may not be immediately evident. Certain technical, market and site-specific factors will favour one technology over the other; investors need to be aware and understand these factors in order to make the best investment decision. Hatch has compared the merits of both technologies regarding plant configuration; type of iron ore processed; energy consumption and flexibility to use a variety of fuels; ability to produce the required pellet quality; required plant capacity and scale; operating and capital costs and environmental performance. A technology assessment checklist that investors should consider when making a new pellet plant investment decision is presented.CITATION:Huerta, M, Bolen, J, Okrutny, M, Cameron, I and O’Leary, K, 2015. Guidelines for selecting pellet plant technology, in Proceedings Iron Ore 2015, pp 45–52 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By A M. Mueller

St Helena tunnel is the centrepiece of the Pacific Highway upgrade from Tintenbar to Ewingsdale, abbreviated and commonly known as T2E. At the deepest point the twin tunnels run 45 m below the ridge line of St Helena Hill, located about 5 km west of Byron Bay. The tunnel breakthrough was achieved early in 2014 and the works for permanent lining will be completed in early 2015.Once the project will be handed over to the public in 2015, T2E will deliver a safer highway and uninterrupted traffic flow between New South Wales and Queensland. The design speed in the project area has been set to 110 km/h by the client Roads and Maritime Services (RMS), which will reduce the travel times between Brisbane and Ballina to just over two hours.The two tubes of the tunnel have been designed to accommodate three lanes in each direction with shoulders and walkways on either side of the carriageway. These requirements result in a huge cross-section of about 20 m width and an excavated area of about 210 m2.With the tunnel alignment being situated in basaltic rock, St Helena tunnel is conventionally driven. The selected excavation method was predominantly drill-and-blast with temporary support being installed immediately after the excavation. Despite the wide span of the tunnel, the geology allowed the tunnel perimeter to be supported by only rock bolts and a layer of shotcrete over the majority of its length.Due to environmental reasons one of the approval criteria of the project was that the tunnel must not have a detrimental long-term impact on the groundwater system within St Helena Hill. Consequently the tunnel has been designed as a fully tanked structure with a waterproofing sheet membrane installed on the temporary shotcrete.The permanent structure of the tunnel has to meet a 100-year design life and it is designed as a cast in situ concrete lining. Considering the water pressure on the lining the concrete is reinforced with a significant amount of bar reinforcement.The presented paper provides a more detailed explanation of the geology and the consequential temporary and permanent support measures together with the waterproofing system.CITATION:Mueller, A M, 2014. Pacific Highway upgrade from Tintenbar to Ewingsdale (T2E), St Helena Tunnel, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 419–424 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By T Horberry

This paper describes work conducted as part of an overall research project that aims to identify current and emerging trends in the development of automation and remote mining technologies, and to provide an operator-centred perspective to the design and deployment of such systems. More specifically, this paper outlines a research and development process being constructed to examine the issues of the human skills and capabilities required to operate or maintain automated/remote controlled mobile mining equipment. A human factors approach presented here, where the focus is upon designing equipment interfaces to fit operators, rather than purely designing and deploying the equipment based on a technology-centred approach. However, the importance of training to help develop the required skills and capabilities is also emphasised.The work built on a full review of the literature about the effects of automation in mining and elsewhere, extensive interviews with different stakeholders in mining automation and recognised best practice regarding designing for the human element in automated systems. The human element research and development process proposed is in four stages, ranging from understanding the tasks involved in both manual and automated equipment operation through to user trials to ensure that the automated systems are acceptable to operators and are fit for purpose.It is outside the scope of the current paper to present the full data collection described by this four stage process, but an overview of what will be collected is presented. As such, this paper focuses on the broad methods being developed, rather than the specific results to be obtained. The ultimate objective is to apply a broad ‘technology assessment’ approach to the design, deployment and evaluation of automated mining technologies, in particular by considering the user-centred design implications of these technologies.

Nov 22, 2011

By D J Maconochie

The use of rock bolts as permanent support has been prohibited by client specifications in several recent large tunnel projects in Australia. The justification for this appears to lie in concerns with proper and verifiable installation procedures rather than concerns with the intrinsic durability of the corrosion protection systems. However, in civil tunnels, preventing the use of permanent rock bolts for long-term support results in the use of cast in place concrete lining which in some instances would otherwise be unnecessary.

Mar 8, 2011