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By M K. Nahian, R G. Reddy

The thermodynamic model for species distribution in aluminium chloride (AlCl3) and 1-butyl-3- methylimidazolium chloride (BMIC) system was developed. The experimental thermodynamic data, considering a range of aluminium chloride species, such as AlCl4-, Al2Cl7-, Al3Cl10-, Al4Cl13-, and Al2Cl6 were used in developing the model. When the XAlCl3 was in the range of 0 to 0.50, only anion species Cl- and AlCl4- were existing in the solution. As the XAlCl3 value increased more than 0.50, the available anions were Al2Cl7-, Al3Cl10-, Al4Cl13-, and Al2Cl6. Specifically, the concentration of Al2Cl7- increased in the composition range from 0.50 to 0.67 XAlCl3, after which it decreased. This change in the concentration of Al2Cl7- was due to its reaction with excess AlCl3, leading to the formation of Al3Cl10-. The average cathode current density was determined by the electrochemical experiments varying XAlCl3 from 0.50 to 0.71 in the AlCl3:BMIC solutions. The average cathode current density increased as the XAlCl3 increased from 0.50 to 0.67. However, it decreased when the XAlCl3 > 0.67. This trend can be attributed to the electroactive species Al2Cl7-. The Al2Cl7- promotes the reduction rate at the cathode, resulting in an increase in the average cathode current density.

Aug 21, 2024

By A Späth

Active explosion barriers are used to contain and suppress a methane gas and/or coal dust explosion propagation, including localised mine fires. Early research indicated that these active explosion barriers could be used on a mechanised cutting machine, making it the only technology that could suppress an explosion during its propagation phase at the cutting face. Thereby not only adding protection during mining operations but also reducing the development of toxic gases, fatal temperature increase and fatal overpressure build-up. During their evolution over the last two decades, further advantages of Active explosion barriers were proven in mine operations in countries such as South Africa and China. Characteristics such as effectivity, efficiency, mobility and space restrictions allow these systems to be used in various locations within a mine operation, including highwall operations. This improved technology contribution to safer coal mining was recognised by mine operators, workers and regulators. The Queensland’s Recognised Standard 21 (Resources Safety and Health Queensland (RSHQ), 2021) stipulated active explosion barriers as a technology to ensure the safety within their underground coalmines. The mobility and flexible implementation of the active explosion barriers allow a feasible and practical solution for all critical locations for explosion and fire management in an underground coalmine. The conformance to the Recognised Standard can be achieved all underground coal mining operations such as Bord and Pillar, and Longwall mining. This paper describes the conformance, implementation and use of Active explosion barriers for Longwall mining and development as well as Bord and Pillar mining in Queensland’s underground coalmines.

Oct 12, 2022

Many young mining engineers do not consider consulting as a possible job, believing that many years of working on-site is required to achieve practical experience, develop expertise and acquire industry contacts. However, mining consultancies employ engineers with varying levels of experience, including part-time university students, graduates and engineers who are relatively new to the industry. This paper outlines the role of a young engineer in a large mining consultancy and the benefits to both the consultancy and the client of having a mix of consultants with a diverse range of experience. From the authorÆs perspective, the work experience, lifestyle and rewards of mine consulting are compared to site based work, including a discussion on whether consulting is able to offer the professional development that a young engineer needs.

Jan 1, 2009

By S Benson

Staurolite is one of the major contaminant minerals contained in the Tiwest Cooljarloo orebodies. Approximately 80 per cent of staurolite in mined ore, reports to the heavy mineral concentrate that is supplied to the Dry Mill. Staurolite in heavy mineral concentrate is typically five per cent by weight and has no significant effect in the Dry Mill other than to occupy equipment space, reporting as a tailing, that requires transportation and disposal back to the mine site. Staurolite is an aluminosilicate with a MohÆs hardness of 7.5. It is known to have potential as an abrasive blast agent and it is produced in substantial quantities in the USA for that purpose. Research indicated that there was potentially a market for staurolite within Australia, as a replacement for some of the lower grade abrasives as well as a material of choice. A small tonnage of staurolite product was manufactured through a simple circuit within the Dry Mill in December 1998. This was subjected to industrial scale tests by external companies specialising in sand blasting. The most significant batch of tests were conducted at the Tiwest Chandala site on plant and equipment undergoing corrosion repairs. Staurolite was tested against three other commercially available abrasives and compared very well with respect to surface profile, surface texture, coating adhesive strength and dust generation. As part of a due diligence study, free silica, radiation and heavy metals contents of spent abrasive and dust was investigated. This information was needed to seek approval from the appropriate Western Australian statutory authorities to sell staurolite as a product. Approval was received in November 1999. Tiwest has since installed a production circuit in the Dry Mill capable of producing 20 000 tpa of Staurolite.

Jan 1, 2001

By J P. Sykes, A Trench

"The common-held view of the future of copper mining is one of declining quality of mineral resources and increasingly limited long-term development options. This decline, in turn, is viewed as inevitably leading to increasing economic, socio-political and environmental costs. As a result, new technologies and innovations will be required to mitigate cost escalation. The future is therefore typically summarised as a battle of a ‘below-ground’ declining quality asset base pushing costs upward versus ‘above-ground’ technology and innovation driving costs downward. The role that high quality new mineral discoveries could play in mitigating industry cost pressures is typically understated, if considered at all. New high quality discoveries can be mined at lower cost than existing assets and potentially if discovered in the right locations within a more amenable contemporary environmental and socio-political setting. Such deposits, once discovered, would improve the overall quality of the industry asset base, as well as benefitting their owners substantially through higher margins. However, to target new high quality deposits explorers need some understanding of the nature of high quality copper mines in the long-term future. Conventional scientific and economic techniques for analysing the future of copper supply, generally by studying the project pipeline, ignore as yet undiscovered resources and also struggle to fully incorporate the multiple internal and external factors that could impact upon copper mining practices in the future.Scenario analysis is specifically designed to consider multiple factors interacting in the future, and is thus more creative than simply looking at the visible project pipeline. The use of scenarios is therefore potentially capable of providing insight into aspects of the future of copper mining about which little is currently known or that remains considerably uncertain. In this study, the Oxford University Scenarios methodology was employed to analyse different plausible futures for copper mining and the consequent implications for exploration targeting strategies. The scenario analysis highlights two key dimensions or axes that serve to map out potential industry futures: firstly the technical and economic optimisation of the existing industry; and secondly the generation of new prospects or ‘search space’ for the copper industry. These two axes in turn frame four different scenarios for the future of the copper mining industry. These copper mining scenarios are then compared to the 20 largest existing copper mines and projects, and their owners, to determine if any represent an appropriately robust exploration targeting proxy: none do. The paper therefore concludes that efforts by industry are required to generate mine concepts that would be viable across all scenarios, and thus act also as exploration targeting proxies. In the interim, companies will have to seek to build portfolios that create an overall robust asset base, out of individually less robust assets. Failure to do this implies that consequential, irreversible strategic decisions lie ahead for the copper mining industry, which may be a threat to both incumbents and the very industry itself. This situation makes strategic exploration targeting in the copper industry very difficult.CITATION:Sykes, J P and Trench, A, 2016. Using scenarios to investigate the long-term future of copper mining and guide exploration targeting strategies, in Proceedings International Mine Management Conference, pp 265-290 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 22, 2016

By S Grant, S Emeric, P Baker, E Jones, D Clark

As we strive for a sustainable and resilient future, repurposing assets has become a top priority. In Australia alone, we have a significant number of mineral projects in the pipeline, extensive existing operations, and over 50 000 legacy sites. Collectively, this presents a unique opportunity to be a world leader in mine rehabilitation. Complex stakeholder landscapes, inflexible policies, aged regulatory frameworks, technical uncertainties and increasing liabilities are all barriers hindering effective transition of legacy assets. The impetus for change is further catalysed by shifting consumer preferences, workforces in flux and regional Australians questioning what the transition means for their local community. We need innovative approaches to take a leading role in the industry and support global efforts more broadly. Co-designing an ambitious, shared vision spanning projects, operations and legacy assets with all key parties is a fundamental step to unlock and realise maximum societal, environmental, economic and reputational value. Serious play and gamification can further enhance this visioning process.

Aug 2, 2023

Historically the insurance industryÆs involvement in any project has been relatively late in the process. Often it was a case of the last item to be ticked off the checklist has been to ensure that the insurance is in place. However, in more recent times insurers have imposed more restrictions on the cover they are prepared to provide, which has in some cases necessitated a change in the contracting structure to accommodate the insurance policy(ies). In addition, changing contractual practices have changed the allocation of risk between the various parties involved. This calls for a more proactive approach to the design and implementation of an insurance program for both the construction and operational phases of any resource project. This paper explores how a risk managed approach to the design and implementation of an insurance program for a resource project can align itself with current management approaches to project development. From the authorsÆ experience, this approach is best adopted early on in the project (often in conjunction with the bankable feasibility study) and follows AZ/NZS4360 to objectively examine and compare a wide range of risk exposures of the project in a time-effective manner across the following areas: personnel; environment; general management; compliance û legislation, systems, protocols; asset management; change management; financial impacts to the organisation; products/services; service delivery; and technology. Having identified and then analysed the risk exposures according to common consequence and likelihood ratings the next step is to develop a risk map of all considered exposures. The true value of this approach lies in the development and implementation of a risk treatment plan for identified exposures where the exposure is unacceptable. The plans will lead to the optimal solution to the appropriate risk prevention, risk mitigation and risk transfer options available. This paper also examines other benefits to the project that may arise from adopting a risk managed approach in addition to the ability to design an insurance program which recognises the exposures and the ability of the organisation (and other project parties) to retain risk.

Jan 1, 2007

By Dawson RD

For the past 45 years, the casting of refined lead ingots by The Broken Hill Asso- ciated Smelters Pty. Ltd. (B.H.A,S,) at Port Pirie has been mainly by use of manually operated rotary casting wheels of Newnam design. This style of operation was quite satisfactory as far as standard of product was concerned, but was manually intensive and a relatively high cost operation. With most other large scale lead producers already using automated-casting equipment, an investigation which commenced in 1966, progressed through stages of enquiry, design and development until the present plant commenced trial operations in late 1973, and fully operative in late 1974. While certain features of the plant are sed on overseas practices the plant was signed and built within Australia to BRAS ecifications. As constructed it consists two almost identical casting lines each pable of producing 25 kg ingots at 25 tonnes r hour using straight line casting machines d automated stacking weighing and strapping

Jan 1, 1975

By R Hargreaves, C Morley

The authors often see problems on mine sites that are due to insufficient feedback between technical discipline silos as the realities on the ground fail to inform the models and plans used to drive resource exploitation. Resource modelling, reserve definition, life-of-mine planning, short-term mine planning and scheduling, mine operations and beneficiation operations are all processes that inform each other, but in many instances feedback between these processes occurs in an ad hoc way and only after problems have come to light.Universal reconciliation uses a multidisciplinary approach across the entire mining value chain to identify both opportunity and loss of value and to maximise operational performance. This paper will look at the operational effectiveness of universal reconciliation and will outline the important elements that make it successful, including how to map out the detail underpinning modelling, planning and execution processes. We do this by documenting the physical processes, logical work practices, organisational roles and responsibilities, data origin and quality, working assumptions and information management practices at an operation. The results quickly show how misinformation and assumption causes suboptimal decisions to be taken, where inefficiencies exist and what the opportunity is to remedy these issues.A universal reconciliation study opens up an opportunity for stakeholders to reassess how the operation should be run and how operational effectiveness should be measured. Clear envelopes for reconciliation become obvious and questions about the practicality and data quality can be addressed.A reconciliation code of practice is a key element of a successful universal reconciliation project and the authors outline the important aspects that will provide an operating model, showing the effectiveness of the resource and reserve modelling, the practicality of the mine planning and scheduling practices, how well the mine operations team are executing these schedules and how effective the processing area is given what it is fed. Most importantly, a system that allows operations time to react before the losses become systemic and that is based on identifying early warnings from hard data when these processes start to wobble is outlined. Finally as a case study, the revenue and cost benefits resulting from universal reconciliation diagnostic projects for nine mine sites is documented.CITATION:Hargreaves, R and Morley, C, 2014. Universal reconciliation – a multidisciplinary approach across the entire mining value chain to identify loss of value and maximise operational performance, in Proceedings Ninth International Mining Geology Conference 2014 , pp 411–420 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

One of the major changes in the resource industry in the nineties has been the re-internationalisation of the industry. The history of the resource business has been one of companies from the developed world utilising the cash flows from their operations to explore and develop mines in less developed regions of the world. This resource development has progressively generated wealth and economic development, which in turn, has led to a new generation of exploration and mining projects. In South America, Chile had led the way in a mining resurgence, now closely followed by Argentina, Brazil, Venezuela and Peru. Although Chile has long had a significant copper mining industry, the pre-nationalisation phase was driven by American capital; the current phase has been spearheaded by R.T.Z. - B.H.P. at Escondida with Canadian junior companies, in particular, providing major speculative impetus. The Australian junior companies have not been significant in South America.

Jan 1, 1995

By B Small

CSA Mine, named after the nationalities of the mines first owners being Cornish, Scottish, Australian, is one of Australia’s deepest and highest-grade copper mines. A combination of the modified Avoca method and shrinking was a standard practice where production rings were fired against and bogged to waste fill. This method resulted in dilution and involved rehandling of waste material to refill the bogged stopes in the Western region and the QTS Central. The introduction of pre-charging blastholes using a wireless initiating system (WebGen™) has enabled CSA to design and fire stopes in reverse. This involves the use of a pre-charged Temporary Rib Pillar (TRP) against the waste fill material in a previously mined stope. The temporary pillar reduces dilution and improves conventional bogging as material is blasted towards the drawpoint rather than towards the waste fill material. Additional drill, prep and blast re-work is reduced or completely removed as rings can be charged prior to, in conjunction with, or after, charging of the slot. This is a safer practice as the charge crew spend no time working adjacent to a brow or open void. A TRP trial was conducted in the western orebody at CSA. The risk of exposure to a brow or open void while charging underground, and the bogger rehandling of waste material was successfully eliminated. Once reverse stoping was established in modified avoca stopes at CSA, two TRPs were implemented in challenging ground conditions in the QTS Central region. The TRPs were utilised in a retreating four-way intersection to extract a central diminishing pillar to close the level out. The ore recovered in this stope provided 5 per cent of CSA’s copper for the year. Without pre-charging with a wireless initiating system, two 5 m pillars totalling 6936 t of ore at 7 per cent either side of the stope would not have been recovered. CSA has implemented the practice of reverse stoping in modified avoca stopes using TRP for ten stopes since the successful trial. The development of additional blasting techniques enabled by precharging with wireless initiating systems is currently underway in the QTS North orebody at CSA Mine.

Mar 29, 2023

By D Atheis, S Williams, A Dance, D Taplin

"Resurrected from its former life at the Big Bell operation, the grinding circuit at Evolution Mining’s Edna May operation in Western Australia has many a story to tell. The task of optimising a plant designed for another orebody provides as many challenges as opportunities. Initially faced with a blend of primary and oxide ore, the circuit achieved in excess of 320 t/h until the oxide was depleted, leaving only the much harder primary feed.The 2.0 MW semi-autogenous grinding (SAG) mill and 3.7 MW ball mill were assisted by a 150 kW pebble crusher, but the power limitation of the SAG mill resulted in a drop in throughput. Edna May personnel have been involved in a number of progressive improvements to restore the design capacity of the concentrator and work towards 3 Mt/a or even higher ahead of the gravity and leach recovery circuits.These improvements include: a crush forward configuration of the SAG mill scats partial to full secondary crushing variable speed drive upgrade of the SAG mill lifter and grate design changes ball mill circuit grinding efficiency.This paper summarises the chronology of events that has resulted in significant improvements in throughput by conventional (and in some cases, novel) methods of reconfiguring the existing grinding mills. Lessons learned and hindsight perspectives will be summarised, sharing this educational experience with other operations in a similar situation.CITATION:Dance, A, Atheis, D, Williams, S and Taplin, D, 2014. Grinding circuit improvements at Evolution Mining’s Edna May operation, in Proceedings 12th AusIMM Mill Operators’ Conference 2014, pp 63–70 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 1, 2014

By J Heyes

Historically mining engineers haven't spent enough time planning waste dumps, but waste movement costs often outweigh ore haulage costs. There is a real incentive to plan waste dumps right the first time to minimise rehandle and final closure costs. At BHP Billiton Iron Ore there has been an increasing sophistication in waste dump design and they are becoming as important as the pit design. Closure landforms are now included in mining studies. Closure is embedded in the business planning cycle. The results from the recent life of mine study at Whaleback is a case in point where a base case of the shortest hauls with no closure constraints was compared against a closure case. A properly planned and executed waste plan revealed that no rehandle was required and haulage costs were eight per cent less if closure design implementation was carried out concurrent with mining. At cessation of mining the landforms were such that decommissioning of critical acid rock drainage dams and coverage of exposed pyrite areas could occur straight away, without the need for additional rehandle.  The paper also covers design and scheduling elements of waste design both in-pit and ex-pit, management of potentially acid forming material (PAF) and trends in PAF management and designing for final landform closure. This paper illustrates that there is value in terms of costs savings, sustainable outcomes and reputation if the mine planners are involved in the closure planning process.

Jan 1, 2009

By S J. Tear, L D. Queen

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Frieda River Project is located in the north-west of Papua New Guinea. The target commodities for a bulk mining operation are copper and gold associated with a large felsic porphyry system. The project comprises a series of deposits, with the Horse-Ivaal-Trukai (HIT) being the largest. It also includes the adjacent smaller Koki and Ekwai deposits.Previous resource estimates for the HIT were made using 14 separate mineralised domains based on structure, copper grades, lithology and alteration. H&S Consultants (H&SC) has revisited the deposit and concluded that a simpler methodology could be used for resource estimation without using wireframes as hard domain boundaries. This conclusion is based on reviewing all the available geological data combined with geological and resource experience of porphyry deposits.It is generally acknowledged that porphyry deposits form by diffusion of mineralising fluids through the host lithologies, meaning that sharp boundaries are unlikely unless these fluids encounter specific physical or chemical boundaries. It is important to prepare a comprehensive geological model prior to attempting resource estimation as it forms the framework for the estimates; however, not all geological features may be relevant to the distribution of mineralisation and there can be a tendency to overcomplicate the estimation process by using too many domains. Unless a hard boundary can be identified consistently and unequivocally, it is generally better not to use a boundary in that location.H&SC completed unconstrained models with no top-cutting using both a simple flat search ellipse and a steep search ellipse to generate global resource estimates reported within a predetermined pit shell at a 0.2 per cent copper cut-off. Both outcomes are within 10 per cent for the tonnes, contained copper tonnes and gold ounces compared to the constrained resource estimate. The slight differences are most likely due to the different search strategies, but also indicate the robustness of the unconstrained modelling approach.CITATION:Queen, L D and Tear, S J, 2015. The Frieda kiss – keeping it simple , in Proceedings PACRIM 2015 Congress, pp 361–368 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By J Lombardi, M Weidenbach

"OZ MineralsÆ Prominent Hill copper-gold concentrator is located 650 km north-east of Adelaide, 130 km north-east of BHP BillitonÆs Olympic Dam operation and 130 km south-east of the regional township of Coober Pedy, in the Gawler Craton region of South Australia. The concentrator was built in 2008 and commenced commercial production in early 2009. The Prominent Hill concentrator is comprised of a conventional grinding and flotation processing plant with a 10 Mt/a ore throughput capacity, operating well over the design rate of 8 Mt/a. Increased throughput rates have seen a decreased water recovery from the tailing thickener due to operating above design. Subsequently, greater pressure was placed on the site water balance and bore field off-take rates due to increased evaporation losses from greater volumes of water reporting to the tailing storage facility. This resulted in a trade-off between water availability and milling rates as part of the operating strategy.Two projects were implemented to increase the tailing thickener underflow density, thus improving water recovery directly back into the operating plant, reducing water losses via evaporation and decreasing the reliance on the bore field system operating at maximum rates to maintain mill throughput. The two projects were: tailing thickener feedwell redesign implementation of the Manta Cube control system.This paper discusses the background, implementation and benefits attained from these two key projects. Combined they have allowed a two to three per cent increase in tailing thickener underflow density to be consistently achieved, which has allowed greater water recovery. As a result, the processing plant has been able to operate at higher throughput rates when required, with greater water availability in the process plant recirculating system and a reduction in occurrences of the plant being æslowed downÆ due to water supply shortfalls. Both projects have also delivered a significant reduction in flocculant usage.CITATION:Weidenbach, M and Lombardi, J, 2012. Tailing thickener operability and control improvements at Prominent Hill, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 137-142 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 29, 2012

By M R. Drumond

The present work presents a new theoretical interpretation of the flotation process, which can also be applied to other mineral processing physical unit operations. This interpretation is part of the æModelo OperacionalÆ (Operational Model) that was developed as an attempt to establish a new theoretical basis for mineral processing unit operations. In the case of flotation, a book was edited by one of the authors in Brazil (Mass Concentration by Froth Flotation, in Portuguese and Spanish).The model establishes a link between a natural phenomenon (migration of particles from the pulp to the froth) and a real industrial phenomenon (mass concentration by operational interference). In this model, flotation is viewed as a phenomenon of macromolecular mass transport (of particles) between froth and slurry phases. Mechanisms for mass transport and particle flow between phases as a function of the hydrophobic potential in each phase are discussed. By establishing the so-called equilibrium distribution curve between phases it is possible to calculate macroscopic balances that are related to metallurgical results, which in turn are a function of the operational line that is required by the process itself. The number of cleaning stages and their efficiencies can also be determined by simple laboratory-scale experiments.

Jan 1, 2005

Western Australia has often been referred to as the fly-in, fly-out capital of the world. Fly-in, fly-out is a commonly used practice in Western Australia due to the geographic size and isolated location of the vast resource projects. In the State today, approximately half of all resource sector employees operate on a fly-in, fly-out basis, with a minority utilising drive-in, drive-out arrangements. fly-in, fly-out arrangements are generally beneficial from a sustainability perspective, delivering significant economic, social and environmental benefits to regional communities, the State and nation as a whole. Skills shortages and labour supply issues mean that the industry will be required to discover new ways of attracting and retaining employees, one of which is the adoption of fly-in, fly-out work journey arrangements. By 2015, the minerals sector in Australia will need to employ 70 000 more employees than it currently employs to achieve predicted increases in output. Of the 70 000 additional employees required, 42 000 will be required in Western Australia, almost 15 000 in Queensland and approximately 5000 in both New South Wales and South Australia. The fly-in, fly-out lifestyle as a preferred method of employment should be recognised as a valid lifestyle choice by all members of the community, offering a profound improvement in the quality of life for large numbers of employees and family members. It should be acknowledged that whilst fly-in, fly-out is a preferred option for many companies and their employees, individuals who make a choice to engage in fly-in, fly-out must balance the difficulties associated with the work û isolation and separation from family and friends û against the economic and lifestyle benefits that the work offers. This paper aims to illustrate the significant steps that the resources sector has taken to facilitate the fly-in, fly-out choice by ensuring that the commute option is a safe, attractive and manageable work journey arrangement.

Jan 1, 2008

By I Gipps

Each of us has a vision of what the future mine will be and, generally, these visions have many similarities and some differences. One of the major discrepancies in visions of the future mine is not the ultimate goal but the path to achieve it. Many of the future concepts require a radical re-thinking of how things are and will be done yet. So how do we reach this visionary future mine? We need a path that satisfies both our future aspirations of a high tech gee-whiz operated from our iPads and the unfortunately mundane approach that says ‘we must know the method works, ie nothing new’.This paper explores how, within a research based organisation, we firstly set our ultimate goal and then divide the path into realistic technology development chunks that would appeal to mining companies to progress within their organisational constraints. Through examples, such as, automated LHDs, communications systems, surveying and localisation, rock cutting and geological sensing, we illustrate how this path will get us from the here and now to the out there future.This paper also demonstrates CSIRO’s short, medium and long-term research in many of the areas needed to create the Future Mine: mining methods, automation and remote control, mine communications, mapping and mission planning, geological sensing and, importantly, human-system integration, which examines how to effectively present data as information to operators and supervisors in an intelligent and useful manner.

Nov 22, 2011

By W Ward, J Clegg, R Barnes, T Zhong

This paper provides an overview of methods for measuring tunnel deflection and construction’s effects on the surrounding environment during and post construction. It will also review illustrative case studies from within Australia and overseas that are most relevant to local construction conditions. Systems illustrated include; vibrating wire and fibre optic strain gauges, extensometers, load cells and piezometers. A novel system using radar interferometry which requires no contact to the structure will also be investigated.In Australia, the majority of tunnelling activity occurs in urban areas (or in the case of mining in rural area) with limited seismic risk. However, the unexpected movement of tunnels is an important factor for structural engineers to monitor. During construction, monitoring is focused on the performance of the tunnelling lining, the supports under real conditions and the effects on surrounding infrastructure. After construction, monitoring will determine the effect of live traffic loads and can also evaluate the durability and any degradation of the tunnel. The aging of some tunnels or the forces subjected by nearby major construction can directly lead to a decrease in structural stability and deformation.The conventional way of inspecting and monitoring those tunnel movements is to have engineers physically enter the tunnel and carry out the measurement work. Manual techniques include tunnel wall convergence checks or total station measurement. However the associated costs are high and measurement process is difficult as some tunnel areas are inaccessible and the data collection interval is limited by the speed of the operator.Automated sensor networks utilising extensometers, fibre optics sensors or strain gauges can be used on tunnel segments or surrounding buildings. Ground settlement measurement via boreholes or hydraulic monitoring points and remote measurement of dynamic deflection can be taken using microwave interferometry.CITATION:Ward, W, Barnes, R, Zhong, T and Clegg, J, 2014. Sensors and systems for the measurement of tunnel movements during and after construction, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 209–218 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By M Gerards, M Steinberg, T Graham

The quality and quantity of Australia’s secondary deposits, which include tailings streams and tailings dams, are higher than most countries’ primary deposits. In addition, these secondary deposits have already been mined and processed, meaning that the recovery of high-grade product requires low capital and operating costs.The most widely used process for the recovery of these valuable fine and ultra-fine hematite iron particles is the wet high-intensity magnetic separation technique, originally developed by Dr Jones over 55 years ago. Many of the original machines are still working today.The aim of this paper is to demonstrate the capabilities in terms of grade and yield of using sophisticated magnetic separation modules. All results and figures are obtained from test work and design and engineering work with material from the Pilbara. In addition, consideration is given to dewatering of iron ore product and tailings.Two types of tailings have been identified for processing. Firstly, tailings that have already been deposited in a tailings storage facility, and secondly, live tailings streams from an existing wet iron ore beneficiation plant. In both cases, the technical and practical results are shown along with relevant flow sheets and plant layouts. Finally, this paper highlights the total predicted power and water consumption, capital requirements and projected operating expenses.The results show that the operating costs are significantly lower than the mining and processing operations that are required for an equivalent amount of iron ore. The recovery of iron depends on various factors but is within the 30–50 per cent range at an equivalent grade to the mainstream product. Another significant benefit is that the magnetic separation process is water positive, meaning that water is released rather than added in the process.The processing of the Pilbara’s secondary deposits will therefore result in an overall reduction in operating costs, an increase in product yield from a plant, extend the life-of-mine and offer environmental benefits by reducing the tailings footprint and water usage.The quality and quantity of Australia’s secondary iron ore deposits and tailings are such that many other countries would judge these as equivalent to primary deposits. Furthermore, these tailings are already mined, available and liberated to such an extent that the recovery of a valuable product is highly economical in terms of capital expenses and operating expenses.CITATION:Steinberg, M, Graham, T and Gerards, M, 2015. Recovery of iron ore fines and ultrafines from tailings by using wet high-intensity magnetic separation – JONES WHIMS, in Proceedings Iron Ore 2015, pp 191–196 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015