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By Fejes G

An integral part of the Brisbane Suburban Railway Electrification involved the relining, refurbishment and track lowering in the Roma Street, Brunswick Street and Gloucester Street double track tunnels. The design and the construction procedures had to satisfy the Queensland Railways electrification clearance and track standards and the requirements of maintaining track services through the tunnels during work. Refurbishing of the tunnel linings was carried out to extend the life of the tunnels.

Jan 1, 1981

By D Suppel, Y Miezitis, S Jaireth

The competition between various options for the use of land is ever increasing. Commonly in Australia large tracts of land were un-encumbered by sweeping land use option limitations, but this situation has been rapidly altering in recent decades as governments are obliged to maximise the utility of the land for a broad range of competing interests. While the interests of miners have always been considered, the effects on limiting access to land for exploration and possible mining have not always been effectively incorporated into decision-making processes. As a result the challenge for national and state organisations representing these interests has been to develop a transparent process to allow for the mineral potential of an area to be systematically assessed and for information to be presented for use by specialists and non-specialists. Government agencies are called upon to implement government policy but also to provide accurate and meaningful advice which can assist in policy and land use decisions. Commonly timeframes are short and information can be less than complete. Nevertheless on-going decisions are made based upon the best available understanding. It is in this operational framework that the methods described in this paper are set. The paper describes a process for quickly and systematically providing advice on mineral potential for use by government agencies and ultimately the community within tight time and resource constraints. It is a method of combining the accumulated knowledge about mineral resources and their potential and presenting this information in an easily accessible form which can be used in a negotiation and policy development environment. Development of the method was undertaken to meet the needs of the Regional Forestry Agreement process in Australia. The method has been applied to study areas in New South Wales, Tasmania, Western Australia and elsewhere. Examples in this paper are taken from north eastern New South Wales.

Jan 1, 1999

By A Lechner, T Baumgartl, S Arnold, P Audet

When revegetation is a part of a rehabilitation strategy at mine sites in arid and semi-arid environments, its success can be strongly affected by the availability of water prior or during the time of seed dormancy, germination and early growth of seedlings. The semi-arid and arid environments of northern Australia are characterised by highly variable and erratic rainfall and hence the actual weather conditions at and around the time of germination and seedling emergence play a critical role in determining the success of plant establishment and the type of plant community that may develop.Using available climate data, an analysis has been undertaken and a set of indices has been developed which describe the suitability of the climatic conditions for rehabilitation. In total, eight sites from Queensland and one site from New South Wales, Australia have been analysed. It could be determined that regular rainfall and relatively short periods of water-deficit are key characteristics of climate suitability. A comparison of the locations studied allowed the separation into suitable and susceptible locations in terms of the availability of water, amount of rain and duration of drought between rain events.In our experience, specific estimates of climate suitability are rarely incorporated into the design of mined land rehabilitation programs. We consider that the regional intensity, seasonality and extremity of climate represent an overarching component of landscape complexity, which in turn will influence the development of post-disturbance ecosystems in these regions. This paper presents the outcome of climate analyses paired with the development of suitability indices. A conceptual framework is presented explaining the suitability matrix and its incorporation as a prognosis tool to achieve greater certainty for success in rehabilitation development.CITATION:Baumgartl, T, Arnold, S, Audet, P and Lechner, A, 2014. Development of climate-based suitability indices for the improvement of success in rehabilitation, in Proceedings Life-of-Mine 2014 , pp 483–490 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By S Pontual

Compact and field portable infrared spectrometers have been increasingly used over the past few years by an exploration industry constantly searching for a technological edge and the ability to more accurately and rapidly assess project areas. In particular, this technology allows large amounts of data to be rapidly collected on-site and sample mineralogy, mineral crystallinity and mineral composition to be quickly assessed. In recent years, short wave infrared (SWIR) reflectance spectroscopy has proved useful in a wide range of geological environments and at various stages of exploration programs, from grass roots reconnaissance through drilling programs and resource evaluation. Unfortunately these data have frequently been analysed and interpreted in isolation using time consuming data analysis techniques removed from the realities of a fast moving exploration industry. This paper presents new analysis techniques which allow these data to be efficiently integrated in the exploration program. Although SWIR data contain a wealth of mineral information it is impractical to use this information in its raw form. A more effective approach involves the extraction of key characteristics of these data (ie mineralogy, mineral composition and crystallinity) as numerical values, and the integration of this ædigital mineralogyÆ with more conventional exploration datasets (eg geochemistry, coordinate data, etc). This paper demonstrates that the integrated analysis of sound geological observations, geochemical, spatial and spectral data can quickly lead to a greater understanding of the nature and distribution of target mineralisation. As a first step, software driven pattern matching routines enable the identification of the major clay mineral species in a series of samples (eg kaolinite, montmorillonite and sericite). This allows the major alteration facies and their spatial distribution to be identified. Quantification of diagnostic absorption feature characteristics then allows more accurate determinations of mineralogy to be made (eg mineral composition and crystallinity). Examples of the application of SWIR analysis for alteration mapping from selected porphyry and epithermal systems from around the Pacific Rim are discussed. The data presented are derived from a variety of locations and sample types including drill core, ridge and spur rock chip samples, soil samples and geochemical pulps. In these large alteration systems, the spectral data can be used to describe and map the distribution of various alteration facies as many of these are characterised by clay and phyllosilicate mineral assemblages and are detected by SWIR analysis (eg smectite, chlorite, biotite, illite, muscovite, kaolinite, dickite, pyrophyllite, alunite, etc). In addition, the ability to evaluate even subtle trends in mineral crystallinity and composition is often vital in these systems when looking for vectors towards higher temperature parts of the system. In addition to detailed evaluation of mineralogy, the integration of digital mineralogy data with geochemical data leads to the ability to describe not only geochemically anomalous intersections or regions but also to recognise associations between subtle changes in mineralogy and target mineralisation. This is often important because understanding these mineralogical associations can lead to more accurate targeting and rapid assessment of the project.

Jan 1, 1999

By E Yurakov, D J. Ashelford, M I. Slate

The push for increasing coal production rates continues to place increasing demands on mine management to safely and effectively control seam gas. Gas drainage strategies applied vary in both effectiveness and form. Methods employed are a function of assessed risk, gas reservoir characteristics, surface and underground access, budgetary constraints and gas utilisation potential. With the aim of establishing and optimising the effectiveness and efficiency of gas drainage systems, Australian coal miners in cooperation with gas management specialists are embracing the use of gas reservoir simulators and gas emission models. This paper discusses the evolution of gas drainage practices in Australian underground coal mines and the role of gas reservoir assessment methods in optimising gas drainage systems and gas production forecasts.

Jan 1, 2005

The role of the mine geologist in a business perspective is self-evident to some, but to others it may be a new concept. All mine geologists need to know exactly how they add value to the business if they are to be successful. Alternatively, if they do not add value, then they will become redundant. This paper seeks to understand some of the contributing problems that hinder the mine geologist from operating in a business perspective. In doing so, a new context (for some) is proposed to aid the mine geologist and the operation gain greater value from geology. The proposal suggests how to ensure that the activities of our geologists are intrinsically linked to the business process that we are involved in. The mine geologist can and must play a pivotal role in the success of an operation. To do this, they must understand some principles of business such as:process, customer/supplier relationships, and organisational structure. Our geologists must know the business objectives, understand the product that the customer needs and use their geological skills to deliver the product safely, on time and to specification. As geologists, we can be instrumental in ensuring that the operational environment is structured in such a way that maximum value is realised, not only from the mine geologists but the entire site team. In doing so, mine geologists will realise their full potential in delivering the outcomes the business demand, and therefore be recognised as strong contributors to business success.

Jan 1, 2000

A mathematical model for spontaneous combustion of coal with moisture included is presented in this paper. The one-dimensional unsteady state model consists of conservation equations for oxygen, water vapour and inherent moisture of coal and energy for both gaseous and solid phases. A first order Arrhenius reaction rate for oxidation under both pore diffusion and chemically controlled reaction regime is considered. The rate of evaporation or condensation is also considered as a function of temperature of coal, water content of coal and gas streams. The equation of the model is solved numerically by the finite difference technique. Influences of different parameters on the process of spontaneous combustion can be examined by using this model. Also the model can be used to simulate full-scale storage conditions.

Jan 1, 2005

By P Bourke, S Ronkainen

Since the early days of flotation, process technicians have known that the speed at which the froth is recovered over the lip of the cell has a very direct and consistent influence on the grade and recovery of the circuit. No plant would deny that, even to this day, one of the most important aspects of a process technicianÆs job is ensuring that the froth is moving at a desired and controlled speed over the lip. Unfortunately, process technicians cannot watch the froth throughout the entire shift, as there are always other problems to attend to. A considerable amount of work has thus been done to develop a æsystemÆ that automatically measures the speed of the froth. This measurement would then be used in simple controllers to emulate the steps taken by the process technician in correcting deviations of the froth speed from its desired level. Many of the earlier attempts to measure speed were ineffective, as they were unable to cope with turbulence on the froth surface. The FrothMasterÖ instrument makes use of machine vision technologies to measure the speed of the froth over the lip of a cell at a very high sampling rate. This instrument produces an extremely reliable and accurate measurement of the froth speed (as well as other parameters such as bubble size and froth stability). As we will show, the effectiveness of the speed measurement in controlling the performance of the plant is a testimony to its reliability. Three FrothMasterÖ units have recently been installed on the Cadia Hills Gold Mine in New South Wales (Australia). The objectives of this installation were:to control the mass-recovery of two Tank Cells in series on the same level where differences in the hydrostatic head between the two cells result in the cells pulling inconsistently with respect to each other; control of the concentrate grade (per cent copper) from the first rougher; reduction in the frother consumption in the rougher circuit by monitoring the froth speed. A simple controller was designed to react to disturbances in the same way that human operators react. This was done after consultation with the metallurgists and the process technicians at Cadia. The controller had two functions: Stabilisation: The stabilising controller made use of three manipulated variables (level, frother addition rate and aeration rate) to control the froth speed to a setpoint. Optimisation: The optimising controller adjusted the froth speed setpoint based on deviations of the grade (measured in real-time by the OSA) from a setpoint. The plant metallurgist adjusted the grade setpoint based on information about the ore. The results from a 21-day trial have shown the following:The ratio of concentrate mass-recovery between two cells in series on the same level has been successfully balanced, thereby overcoming problems due to differences in hydrostatic heads. It is possible to control the speed of the froth, in mm/s, to within five per cent of its setpoint using the aforementioned manipulated variables. It has also been shown that, for reliable control, it is necessary to control more than just one variable (eg level or air). The grade of the first rougher concentrate has been controlled to within 0.3 per cent of the grade setpoint for long periods of time, which has important implications for the circuit recovery. The frother consumption has been reduced significantly. This paper will thus show that substantial progress has been made to demonstrate the value of using on-line froth speed measurements in flotation plant control to obtain real financial benefits.

Jan 1, 2000

Sophisticated pit optimisation software has allowed mine planning engineers to generate mining outlines that consider the numerous factors that have a major effect on the success or otherwise of a mine plan. The outlines are generally generated using a range of values for which one can assume a fixed mining cost and a variable revenue. During analysis, the expected costs and revenues are used to investigate the cashflow and sensitivities. Ultimately, the final pit and incremental outlines, or shells, are selected for a given expected price. This paper proposes an alternative method for incremental pit shell selection that considers the risk the mine be prepared to accept. The life of mine is divided into a number of Business Risk Periods (BRPs). The BRP represents the period of time over which the owner is prepared to invest capital. During each BRP, the mine will then operate at a selected investment cost which is generally equal to or greater than the minimum required to meet production targets. In this way, a robust mine plan can be produced which allows the mine to react to change without having to alter the incremental shell limits while maintaining a strategic risk profile. This paper will summarise factors to be considered in selection of the BRP and the incremental pit shells within the BRP.

Jan 1, 1998

By C Rizos, A Ng

Land surface deformation can be caused by underground mining activities. The maximum subsidence normally occurs directly above the location of the excavation of the coal seam. In the case where the longwall mining technique is applied, the magnitude and shape of the subsidence bowl are constrained by the longwall structure (pillar). This paper describes the use of satellite radar interferometry for monitoring surface subsidence due to underground mining, as a cost-effective geodetic technique and complementary to conventional ground surveying techniques. This paper uses data acquired by the current generation of SAR satellites û the European ENVISAT and the Japanese ALOS û to monitor ground subsidence in the southern highland coalfield in New South Wales, Australia. An accumulated DInSAR subsidence mine map is produced using six successive ALOS acquisitions. The results are post-analysed with the aid of geographic information systems (GIS) and validated using ground survey data.

Jan 1, 2008

By D Kubik, K The

The New Zealand (NZ) Transport Agency’s Waterview Connection will complete Auckland’s Western Ring Route, a 47 km north–south motorway alternative to Stage Highway 1. The project is being delivered by the Well-Connected Alliance comprising the New Zealand Transport Agency (NZTA), Fletcher Construction, McConnell Dowell Constructors, Obayashi Corporation, Parsons Brinckerhoff NZ, Beca Infrastructure and Tonkin & Taylor.The project involves construction of 5 km of new motorway, nearly half of it underground connecting State Highway 20 (SH20) to State Highway 16 (SH16). The underground portion of the project incorporates twin 13.2 m inside diameter (ID) tunnels 2.4 km long, each carrying three traffic lanes, one for north-bound traffic and one for south-bound traffic. The tunnels are being driven by a 14.46 m outside diameter (OD) 2400 t, tunnel boring machine (TBM) shield that was assembled and launched at the southern portal. It will be turned and re-launched at the northern portal for the return drive to the southern portal where it will be disassembled. This paper presents two major temporary works elements contributing to the successful launch of the TBM: the TBM assembly crane platform and the TBM shove frame and associated components.Tunnel boring machine shield assembly – crane platformThe TBM shield was delivered to site in subassemblies ranging in weight from 100 to 380 t. It was initially proposed to use a 750 t crawler crane sitting above the tunnel portal headwall to assemble and disassemble the TBM. However, this did not have sufficient capacity to allow the TBM shield to advance clear of the tunnel before disassembly commences. To reduce the crane’s working radius a temporary steel crane platform was developed that is supported on the side walls of the tunnel approach trench. This has enabled a smaller, less expensive, 600 t crawler crane to be used and will allow the TBM shield to clear the tunnel before disassembly.Tunnel boring machine launch – temporary worksTo launch the TBM a purpose built steel frame was required for the TBM thrust rams to react against. The shove frame had to be able to transfer the thrust loads from the TBM shield to the ground below and thrust wall behind. A range of potential thrust loads and jacking patterns were examined to develop the design load cases for the shove frame. The shove frame was used to launch the TBM at the southern portal and to re-launch it at the northern portal. Elements of the shove frame will also be used to support the portal faces during the TBM arrivals.CITATION:Kubik, D and The, K, 2014. Waterview Connection – temporary works for tunnel boring machine?launching, in Proceedings 15th Australasian Tunnelling Conference 2014, pp 281–288 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By M Fahey, A B. Fourie

Over the past ten years, the mining industry has witnessed the introduction of a new and innovative mine filling technique known as paste fill, which consists of placing full stream tailings with small amounts of binder and water into underground stopes. Paste fill has benefits over traditional backfill methods, such as higher solids contents than hydraulic fill and easier transportation than rock fill. From a geotechnical perspective, the behaviour of very fine material in a fully saturated state can be complex, particularly when binder is added. Previously, there has been no rigorous solution to understanding the paste fill deposition process, resulting in uncertainty regarding critical aspects such as barricade load calculations. This uncertainty has the obvious consequences of potential barricade failures (including at least 12 over the past four years), and for many operations attempts to deal with this uncertainty has led to excessively conservative filling schedules, restricting production. This paper presents an application of Minefill-2D, the first rigorous model capable of representing the paste fill deposition process. The model couples the processes of material accretion, consolidation and cement hydration to calculate the distribution of stress around a stope (including the total stress applied to barricade structures) during filling. Minefill-2D is a finite element numerical program, which has been verified using laboratory element tests, centrifuge tests and in situ measurements (Helinski, 2008). The authors present a sensitivity analysis, carried out using the model, to demonstrate some of the critical and less critical aspects relating to paste backfill deposition. The results of this sensitivity analysis are used to devise a fill management strategy that can be utilised to minimise the risk of barricade failures and maximise fill rates where appropriate.

Jan 1, 2008

By B A. Wake, G G. Lowder, M J. White

The Tooloom gold field is located within the New England Fold Belt in the far northeast of New South Wales, approximately 130 km south southwest of Brisbane. Gold was first discovered at Tooloom in 1857. Within a few years up to 10 000 people were mining placer gold deposits in the Tooloom valley and a few tried their hand at mining hard rock occurrences as well. Mining of alluvial gold continued in a small way at Tooloom until very recently, but only in the last few years, since Malachite Resources acquired its interest at Tooloom (now 100 per cent), has the full potential of this large, reduced intrusion-related gold field been appreciated. By the mid 1870s, once the alluvials were largely worked out, most of the early miners had made the 270 km trek north to the newly discovered Gympie gold field and Tooloom slipped into obscurity. Such was this obscurity that the Tooloom gold field was not recorded on published Government geological maps until 2001, four years after Malachite became involved. The many hard rock prospects that Malachite has identified in recent years were largely or completely unknown. Tooloom is a good example of blinkered thinking when it comes to modern mineral exploration. The New England province in NSW has long been the æpoor relationÆ to the much better known and more highly favoured Lachlan Fold Belt in NSW. It has also suffered serious neglect compared with the Queensland part of the New England Fold Belt that hosts such major gold deposits as Mt Morgan (>7 Moz), Gympie (>3 Moz) and Cracow (>1 Moz). Tooloom is proof that prospective geology does not stop at state borders.

Jan 1, 2004

By P J Savory

Ranger is a uranium mining operation located within one of the most environmentally sensitive regions of Australia. Geology has played an important role in mine planning, operations and rehabilitation since discovery of the deposits 25 years ago. The Ranger orebodies have a reserve total of 166 300 tonnes of U308 including 90 400 tonnes of U308 at North Ranger. At current milling rates these reserves give a mine life greater than 40 years. The uranium is hosted in Lower Proterozoic rocks of the Cahill I ormation and is associated with strong chlorite alteration. In pit grade control involves the use of calibrated probes and a radiometric truck discriminator allowing fast, accurate grade determination of material. Ore is defined at a cut-off grade of 0.2 per cent U308. Mineralised material is defined by the Uranium Mining (Environmental Control) Act 1979 (UMEC Act) at a grade of 0.02 per cent U30s. Natural water levels in the #1 Pit area vary as much as 7.5 metres between wet and dry seasons. Ground water inflow into the pit during the dry season is 600 m3/day. No significant slope failures have occurred in the pit. The environmental impact of mining operations is constantly monitored. Rehabilitation of non-mineralised stockpiles is ongoing. This paper discusses the interaction between geology, hydrogeology, rock mechanics and grade control with the present mining operation.

Jan 1, 1994

By Vink L, Johnson N. W, Mackenzie J, Young M. F, Johnston M, Landmark V

The influence of ore textures on metallurgical behaviour is poorly understood for most ores. An alternative method for characterising ore textures and for determining the resulting implications on ore processing has been developed for the Geor

Jan 1, 1998

By C Wels

Current best management practice requires the placement of a cover onto most types of mine waste including tailings, waste rock and/or spent heap leach rock at closure of the mine. The objectives of a cover system may vary from site to site but generally include dust and erosion control; chemical stabilisation of acid-forming mine waste (through control of oxygen ingress) contaminant release control (through control of infiltration); and/or provision of a growth medium for establishment of sustainable vegetation. In our experience, there has been a general tendency by stakeholders to develop performance criteria for cover systems, which are tied directly to these specific design objectives. In many cases, this practice has led to the development of single, often very conservative, numerical values of cover performance criteria such as ænet percolationÆ, ærate of oxygen ingressÆ and/or æplant density/mixtureÆ. In our opinion, there is a need to develop cover performance criteria on a case-by-case basis and with due consideration of the short-term and long-term impacts on the receiving environment at a particular site. This paper puts forward a methodology for developing site-specific performance criteria for a cover system designed to isolate acid-forming mine waste and to control acid rock drainage. The proposed methodology links the predicted performance of a cover system to groundwater and surface water impacts. This way, the appropriate level of control (of oxygen ingress and/or net percolation) required by the cover system can be determined. A case study is presented that illustrates the application of the methodology proposed in this paper.

Jan 1, 2003

By X Hu, J Björkvall, L Sundqvist Ökvist

The metal production industry is a significant contributor to global CO2 emissions due to the use of fossil fuels such as coal and coke. To mitigate these emissions and meet climate goals, innovative and sustainable technologies are required. Molten salt electrolysis is a promising technology that directly produces metals from their precursor sulfides or oxides using electricity. When combined with renewable electricity and an inert anode, the electrolysis process can be carbon neutral. This paper presents the results of two pilot-scale studies on the electrolytic reduction of metal oxides and sulfides in molten salts. The first study focuses on the electrolytic reduction of chalcopyrite in molten NaCl-KCl salt. The results demonstrate that in situ separation of copper, iron, and sulfur is possible, enabling the extraction of all valuable elements without CO2 emissions. Furthermore, the findings underscore the capability to eliminate impurities like zinc, antimony, arsenic, and mercury from the electrolysis product. The second study investigates the electrolytic reduction of pure/synthetic chemicals of wüstite, hematite, and magnetite, as well as a magnetite-type iron ore in molten NaOH salt. The findings reveal a stepwise reduction of iron oxides from high valence to low valence, ultimately leading to the production of metallic iron electrolytically. Notably, this study underscores the challenges associated with the selection of an economically viable and durable inert anode material for efficient oxygen generation. These results indicate that molten salt electrolysis provides a sustainable and green route for base metal production. The use of this technology has the potential to significantly reduce CO2 emissions in the metal production industry, contributing to achieving climate goals.

Jun 19, 2024

This paper describes techniques that have been used at RixÆs Creek Colliery to control blast vibration from throwblasts that face a residential area 4 km in front of the face. The paper describes blast design, face control including laser profiling, selective loading of blastholes after borehole camera surveys, and techniques used to assess the effect of burden variation, the cumulative effect of drilling and delay sequence, and the effects of meteorology.

Jan 1, 2001

This paper cites selected, prominent examples of current, major projects in Southern Africa in both the mining and civil fields. Differences and similarities in the life cycle of mining and civil projects are discussed. A closer relationship between the mining and civil fraternities is beginning to develop and should be encouraged because of the resultant exchange of experience and technology which benefits both disciplines. An attempt is made to assess future potential for new, major projects and trends in the implementation thereof.

Jan 1, 1999

By M Coleman

Information is a key ingredient for successful mineral exploration and development. Whether identifying potential exploration localities from a map, interpreting technical reports or searching a register for operators past and present, the common aim is a parcel of information from which the enquirer can make a decision. Traditional information gathering often requires days or weeks of manual research, studying maps, files, reports etc, before consolidating the results into an investment proposal. In recent times, such methods have largely been replaced by Information Technology, making the process much faster, easier and more centralised. However, notwithstanding some very successful technology implementations, the general rush to computerise everything in sight has left many organisations struggling to cope with the management of large volumes of diverse information. Information management is now recognised as the most important factor in determining the success of information technology implementation. The Northern Territory Department of Mines and Energy (DME) has established a detailed information management strategy to underpin the rapid advance of computer technology within the organisation. A broad base of timely and reliable information is gradually becoming more accessible. It is envisaged that the availability of combined spatial, textual and scientific information will provide a sound basis for decision-making within the Department and the mining industry at large. Although information held by DME will be available at all times (24 hours on-line), its security and confidentiality will be guaranteed. The production of the DME system is aimed at satisfying the corporate objective to facilitate and promote mineral exploration and development. This paper outlines some current developments in the system.

Jan 1, 1994