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In classical drill and blast underground mining methods, especially narrow vein operations economic quantities of broken ore can be left behind following normal mucking operations on the stope floors. The ore left behind can have significant economic value and if not collected can be lost forever. This paper reviews techniques for cleaning this material from stopes that have been used in the past and reviews possible modern techniques that can be applied to ensure this valuable material is removed from the stopes.

Aug 1, 2010

The long-term production schedule of open pit mines that maximises the net present value (NPV) of a given project relies on the proper design of phases (pushbacks) within the ultimate pit limits. There is not a phase design algorithm applied in the mining industry today that gives yearly production schedules that are optimum.The majority of phase design algorithms currently in use by the mining industry aims at grouping the blocks that fall within the ultimate pit limits into phases such that the average value of the blocks within each phase decrease as the size of the phases increase. Current phase design methods are typically based on a pit limit optimisation algorithm, originally introduced by Lerchs and Grossmann (LG) in 1965. To obtain multiple pit shells to be used for the phase design, the LG pit limit algorithm successively applied to economic block models by changing the price of the commodity or some other factor that properly parameterises the size of the pit. These modified economic block models are developed by predetermining the destination for each block in the model based on a breakeven analysis and highest economic outcome between alternative destinations. Phase designs determined by these existing algorithms may be suboptimal if a given project utilises multiple processing facilities for metal recovery and particularly if these facilities have restrictions (constraints) that require blending of attributes in the feed. To overcome these problems in obtaining phases that optimise overall production schedules, a new algorithm is developed at the Colorado School of Mines. The algorithm determines the phases of an open pit mine by taking into account multiple process options for the blocks and period by period blending requirements. This algorithm has been implemented within a software program (the software) and is being prototyped successfully in the design of improved pushbacks at a copper mine in South America and on a gold mine in Nevada. This presentation will demonstrate the shortcomings of the traditional phase design methodologies based on comparison of results coming from the new approach versus the traditional.

Dec 6, 2010

By Seedsman R

The fundamentals concepts of roof support are similar between coal mining, metal mining and tunnelling and yet there are different design approaches, different hardware, and different levels of site investigation. This should not be the case and this paper discusses the key geotechnical issues that should underlie all roof support design - the need to reinforce defects. A design method to build a beam in laminated rock under high horizontal stresses is presented. The method allows for changing rock strengths, defect properties and varying horizontal stresses. At one level the design can be implemented with design charts and tables. Lessons learnt during the implementation of the designs at 5 different mine sites are Discussed.

Jan 1, 1998

By G Pitkin, D Sorley

The purpose of any consultancy is to provide a superior service for their client. Organisational structure is a key element in providing this service and differentiating between consultants.In an organic organisation the emphasis is on effectiveness, problem solving, responsiveness, flexibility, adaptability, creativity and innovation. Such an organisation is able to respond in a timely manner to change because employees are empowered to be creative, to experiment and to suggest new ideas. The process of innovation is triggered by employees throughout the organisation in a collaborative manner.Problem solving becomes a core competence of the consultancy. A multidisciplined approach arrives at superior solutions that are rigorous, holistic, achievable and often novel. It allows the mining consultancy to extract the most from a very talented and experienced team.This paper highlights the advantages of an organic structure for a mining consultancy and how to implement such a structure. It draws on examples of innovative problem solving from feasibility and strategic studies carried out in Australia and Africa.CITATION:Pitkin, G and Sorley, D, 2016. Organic management structure – its advantages in a mining consultancy, in Proceedings International Mine Management Conference, pp 155-162 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 22, 2016

By Stanojevic R, McGlinn PJ, Day RA, Levins DM

This paper reports the results of a number of studies that Ansto has carried out for mineral sands companies concerned about low-levels of naturally-occurring radioactivity in their products. Where measured levels of radioactivity have exceeded allowable levels, Ansto has used specialised techniques to identify the source and distribution of the radioactivity and investigated processing strategies to remove the Contamination.

Jan 1, 1993

By A Annor, L J. Chen

The production of paste backfill has typically been accomplished through the adaptation of existing technology. Thickeners and disc filters have several drawbacks when applied to production of tailings paste backfill. Personnel at CANMETÆs backfill research laboratory in Sudbury, Ontario, Canada have been carrying out research into and development of methods to produce paste backfill using total mill tailings since 1991. Using a silo for production of paste is not a new concept but has been refined to a marketable level. This technology is based on a fluidization principle that assists in settling the tailings to an homogenous state in a silo. Other developments include patented de-watering technology for use in the silo to speed the settling of the solids to a suitable solids content, optimisation of silo geometry, and instrumentation related to paste backfill production and transportation. The advantages to fluidisation technology are in reduced capital cost, reduced operating costs and in the environmental benefits of using full plant tailings over classified tailings or alluvial aggregates. Another major advantage is in the ability of this technology to be retrofitted to existing hydraulic backfill plants to further reduce capital cost. This paper details the development of the new technology as well as the associated cost savings over other technologies. It will also look at the research and development of unique components that make this technology work.

Jan 1, 1998

The Earth Moving Equipment Safety Round Table (EMESRT) was established by mining companies in 2006 to influence manufacturer's equipment design through a process of engagement. 2010 EMESRT member companies include Anglo American, Barrick, BHP Billiton, Centennial Coal, Collahausi, Newcrest, Newmont, Rio Tinto, Vale and Xstrata.Driven by a persistent need for retrofits to new equipment, such as haul trucks, EMESRT initially engaged with Surface Equipment Manufacturers including Caterpillar, Komatsu, Leibherr, Hitachi, Le Tourneau and Terex. These OEMs responded positively to the EMESRT initiative, welcoming the opportunity for dialogue with an aligned industry regarding human factors issues related to equipment design, rather than needing to respond to the disparate range of demands for design modifications previously received from individual customers. This engagement process is about making global sustained changes within the OEM organisations and within the mining companies. It is a very international exercise. For example, over two weeks in September 2010, a total of 21 different miners from ten different companies travelled from Australia, South Africa, Canada, Brazil, Singapore and the United States to engage with OEM counterparts who assembled from the United States, Japan, France, Sweden, Finland and Germany. EMESRT Surface Group representatives completed a whirlwind tour of the major North American manufacturers of mining equipment. Starting in Dallas (Atlas Copco, LeTourneau), this tour passed through Gainesville (Sandvik), Newport News (Liebherr), Guelph - Ontario (Hitachi) and Milwaukee (P&H Mining/Joy Global; Bucyrus), before winding up in Peoria, Illinois (Komatsu, Caterpillar). Over nine meetings, this group engaged with 129 individuals from nine OEMs. The EMESRT group welcomed miners from four non-member companies to come along for the meetings. These companies are Syncrude Canada Ltd, the Kearl Oil Sands Project - Imperial Oil (ESSO), Suncor Energy Ltd and Teck Resources Ltd.Other mining industry sectors have now expanded the EMESRT scope from surface mining to include exploration and underground mining equipment. In 2009, EMESRT was organised into four Technical Groups, consisting of EMESRT member company representatives, to focus on engagement with OEMs of surface, underground coal and soft rock, underground hard rock, and exploration drilling equipment. An advisory group has been formed to coordinate activities between all workgroups and provide strategic direction and cohesion between all activities. The Minerals Industry Safety and Health Centre (UQ-SMI) facilitates and coordinates all EMESRT activities on behalf of member companies. Building on successes with individual Surface Mining OEMs, EMESRT now aims to help OEMs in their transition to a sustainable design process that will incorporate and address specific design philosophies at the concept phase of design, so that significant improvements can be made up front for little cost within the overall budget. EMESRT members plan to educate all stakeholders, internally, within their own companies, and externally, by addressing industry associations, regulators and other end users about new ways of evaluating equipment design based on EMESRT purchasing specifications. This presentation will outline the EMESRT approach and report on progress in 2010.

Dec 6, 2010

By Miller M. J, Bauer J. C

The continuous copper drossing process operated at Port Pine since 1962 has had limited copper removal capacity as determined by a maximum tolerable Cu/S ratio in feed and the level of sulphur in blast furnace bullion. Recent process development has been to overcome these limitations to meet increased copper throughput requirements. A sulphur addition system was developed and installed in August 1987. The system has capacity to increase sulphur input by over 150%, meeting the increased copper capacity requirement and also allowing independence from the upstream process for sulphur supply. Developments in process understanding have been applied within the limitations of the existing furnace design with a 10% increase in the maximum tolerable Cu/S ratio.

Jan 1, 1989

By C G. Sweeney

The underground mining industry is seeing unprecedented shortages in skilled labour. Migration to Australia being at an all-time low is a leading concern, with pandemic-induced border closures and lockdowns only exacerbating the skills shortage, not causing it. The skills shortage is forecast to peak in 2023 and remain high beyond 2025. With this skills shortage in mind, mining companies throughout Australia are trying to deal with stricter protocols around Health and Safety (H&S) legislation, as well as more stringent controls on quality assurance, particularly as underground mines are reaching greater depths and extending into ‘unchartered territory’. The cumulation of this is proving to be a major hurdle in ‘effective’ operational geotechnical management. The drive for automation in mining is bringing another level of complexity. However, ‘once automation is up and running, it presents the opportunity to access talent pools that may not normally be available. There is also a change in skillset that will be required to drive automation. ‘The top two emerging roles that will be critical for the future of the mining industry are artificial intelligence and machine learning (AI/ML) specialists, and process-automation specialists’ (Writer, 2021). If anything positive has come from the pandemic, it has shown that remote working can be effective and that the drive for automation and critical evaluation of skills required on-site should be given greater priority. UQ acknowledges that the industry is changing, and that digital technology is required to be offered in mining related disciplines. Industry and academia need to do more to promote geotechnical engineering in mining and balance the curriculum to suit the future of mining and make it more enticing. The average cost of a geotechnical failure is about $5 million in coalmines and can be into the hundreds of millions of dollars if production is affected (Cartledge Mining and Geotechnics, 2020). The cost of a good geotechnical design far outweighs the potential losses if a failure were to occur. This alludes to the growing importance of experienced geotechnical consultancies playing a pivotal role in managing mine site geotechnical hazards, while the industry is developing the next generation of geotechnical engineers.

Nov 29, 2022

By D Ryan

Following a long period of increase, there has been a reduction in exploration expenditure and activity in Australia over the past two years. During the post Second World War period, exploration was largely driven by mining companies seeking resources to satisfy an increase in world demand, while increasing their asset base as a result of mineral discoveries. In general, return on investment to shareholders was not the major driving force. With the exception of gold the mining industry has been faced with a long-term fall of metal prices in real terms. As a result the net profit return on average shareholderÆs funds in the Australian minerals industry has fallen from over 20 per cent in 1990 to less than five per cent today. Mining is now competing for funds with communication and finance based industries yielding high returns on shareholder investment. Shareholders and superannuation fund managers seeking a high return on short-term investments have indirectly reduced the funds available to the mining industry. Globalisation of the mining industry is leading to the rationalisation of the Australian mining industry as witnessed by mergers and acquisitions of local companies by foreign investors. The return on capital invested in the Australian mineral exploration industry must improve if the industry is to be competitive on a worldwide basis. Failure to achieve this will result in capital flowing overseas or to other industries. Relatively short-term upswings in metal prices which are generally driven by threats to the supply base (eg strikes, mine closures, increases in country risk) often lead to increased capital raisings for exploration funding. As a consequence of the time taken to raise the capital and increase exploration activity, measured exploration activity lags the metal price increases. There are also lags between commencement of exploration and discovery and ore production. In the case of gold exploration expenditure peaked six years after the price rise of 1980 Companies persevering with exploration in the current difficult period will be rewarded because they will be able to capitalise on future metal price rises and a minimised time lag.

Jan 1, 2000

By A B. Christie

The Institute of Geological and Nuclear Sciences' Mineral Resources Programme is currently carrying out research under two major projects:   HAREM (Hauraki Andesite Rhyolite Epithennal Mineralisation) The Hauraki Goldfield lies within a belt of andesite-dacite-rhyolite volcanics of Miocene Pliocene age which is underlain by a basement of Mesozoic greywacke. It contains some 50 separate epithermal gold deposits and is a world-class gold and silver producer. The HAREM project is aimed at improving models of the epithermal gold mineralisation, and to better understand the processes and controls of origin, transport and deposition of the gold.   MARGO - (Marlborough Gold) The MARGO project is aimed at determining the geological factors that controlled the formation of the Mesozoic mesothermal gold-antimony-tungsten deposits in the Marlborough Schist belt. Following reconnaissance work on 12 deposits, our current work is concentrated on deposits in the Wakamarina valley.

Jan 1, 1994

By J-P Franzidis

A technique for determining the recovery of attached particles across the froth phase in flotation that relies on measuring the rate at which bubble-particle aggregates enter the froth is used to investigate the selectivity of attached particles across the froth phase. Combining these measurements with those of other techniques for determining the froth recovery of attached particles provides an insight into the different subprocesses of particle rejection in the froth phase. The results of experiments conducted in a 3 m3 Outokumpu tank cell show that the detachment of particles from aggregates in the froth phase occurs largely at the pulp-froth interface. In particular it is shown that the pulp-froth interface selectively detaches particles from aggregates according to their physical attributes.

Jan 1, 2005

By P Hanna

In an effort to improve returns to shareholders, the Australian Mining Industry has consolidated considerably over the past decade or so. Technical services at mines have been re-structured, whilst those at corporate offices have been all but eliminated. A recent study of the role of the geologist in BM Alliance Coal Operations Pty Ltd (BMA), showed the adverse impact on the companyÆs performance due to a lack of geologists. With an education campaign, to demonstrate the contribution of geologists to the æbottom lineÆ and in increasing the options available to the company, the value of the geology role became better understood. The implications of the loss of invaluable corporate knowledge, when long serving geologists left the company, also became clear. Steps have since been taken to increase the numbers of company geologists, particularly on mine sites. In common with other sectors of the mining industry, the Australian coal industry is experiencing a critical shortage of experienced coal geologists, as companies have found in recent recruitment efforts. This is further evidence that the recommendations from the recent study by World Competitive Practices, commissioned by The Australasian Institute of Mining and Metallurgy, æRising to the ChallengeÆ have not been adopted. People, and the mineral resource base, are the assets from which mining companies gain a sustainable competitive advantage. Geologists, as the nexus between the resource base and people, are in a unique position to enhance the profitability of their companies. To maximise their contribution to the industry, and ensure that they receive due recognition, geologists must adopt a more commercial approach in their work and take a front foot stance in promoting their value to management. Geology is a core competency for all mining companies. The tendency for companies to outsource this function, to the detriment of the company geologist role, is not sustainable in the longer term. TodayÆs geologists need to work closely with management, technical and human resource professionals, universities and schools to ensure their significant value is well understood, and that the industry can attract, train and retain new recruits through the implementation of graduate programs and company career paths.

Jan 1, 2003

MIM Holdings Limited (MIM) committed to a long-term future in copper in the Carpentaria Mineral Province in 1996 with the development of the Enterprise and Ernest Henry mines, and an upgrade of MIMsÆ copper smelter in Mount Isa, and copper refinery in Townsville. The upgrade of the copper smelter will enable the smelter to produce 250 000 tpa of copper with a single primary smelting unit, the copper Isasmelt furnace installed in 1992. The copper Isasmelt furnace currently smelts concentrate containing 145 000 tpa copper. To reduce the risk associated with the copper smelter upgrade, and shorten the ramp up time of the upgraded smelter, two high-rate trials were undertaken in 1997 to demonstrate that the copper Isasmelt furnace could, with an additional 525 tpd of tonnage oxygen, treat concentrates containing 250 000 tpa copper. During the trials the concentrate feed rate to the Isasmelt furnace was increased from its average rate of 100 tph of concentrate to 150 tph of concentrate. The increase in the capacity of the furnace was achieved by: supplementing the installed tonnage oxygen capacity of 595 tpd with an additional 300 tpd supply; reducing variability in the furnace feed rate from ¦25 per cent to less than ¦5 per cent; and reducing tramp air. The Isasmelt furnace smelted concentrate at a rate of 140 to 150 tph for four hours 25 minutes during Trial 1, and at a rate of 150 tph of concentrate for five hours and 30 minutes during Trial 2. The oxygen utilisation was 100 per cent during the trials with the process remaining under control. As a result of the development work for the trials the average treatment rate of the furnace under normal conditions increased by ten per cent.

Jan 1, 1998

Sizing is fundamental technology for each step of ironmaking process. The progress of sizing technology has greatly contributed to the development of ironmaking technology. As the purposes of ironmaking operations diversified particularly since the oil crisis of 1973, the sizing technology made new advance- ment, as represented by pulverization of ser- pentine, dezincification and classification of secondary blast furnace dust, pulverized coal injection, size-segregated sinter charging and a coal preparation control process. These techniques are mostly characterized by the fine grinding of a given type of mineral or coal to heighten the degree of reaction con- trol. This trend is expected to continue Further.

Jan 1, 1984

By P Rubie, B Morgan, J Russell, C Stewart

The relationship between efficient liner exchange, concentrator availability and concentrator profitability is well documented. Russell Mineral Equipment’s (RME) relationship with OZ Minerals’ Prominent Hill site personnel enabled sound collaboration between the two parties. Both parties worked together to identify the sources of productivity and efficiency loss and developed solutions to reverse them.This paper chronicles the identification of production inefficiencies and the resulting removal of mill relining from the critical path through the materialisation of mill relining optimisation strategies. Furthermore, this paper outlines other recent mill relining optimisation strategies developed by RME and tested at Prominent Hill, to demonstrate and achieve further productivity, efficiency and safety improvements.CITATION:Rubie, P, Russell, J, Morgan, B and Stewart, C, 2017. Mill relining optimisation – a story of collaboration, in Proceedings MetPlant 2017, pp 335–345 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

By J Theiler, B Beamish

The presence of reactive metal sulfide minerals in waste rock contributes to the hazard of spontaneous combustion in dumps, as these minerals react with air and water entering the dump at ambient temperatures to form various mineral products and significant heat. This reaction series can also be an initiator of self-heating of carbonaceous material present in the waste rocks if sufficiently high temperatures are reached. Characterisation of these reactive minerals has primarily been to assess the risk of acid mine drainage, which is not necessarily an indicator of spontaneous combustion risk. No systematic testing procedure has been adopted by industry to assess the spontaneous combustion propensity of the waste rock. As a consequence, the principal management strategy for spontaneous combustion has been a reactive approach of dealing with events as they arise.Recent advances in adiabatic oven-testing have enabled more definitive assessment of the spontaneous combustion propensity of coals, including the quantification of the accelerating influence of reactive pyrite (Beamish and Beamish, 2011, 2012; Beamish, Lin and Beamish, 2012). This same test procedure has been used to assess the self-heating performance of metal concentrates and is therefore amenable to assessing the metal sulfide oxidation process from low ambient temperatures. The data obtained from such testing can be used to quantify the more prone waste rock sequences of a mineral deposit in advance of mining. This enables appropriate management planning for emplacement and long-term storage of waste rock in dumps.CITATION:Beamish, B and Theiler, J, 2016. Characterising the spontaneous combustion propensity of waste rock, in Proceedings Life-of-Mine 2016 Conference , pp 93–96 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By E A. Gunn, J Zhou

In this paper a project to develop a joint optimisation/simulation model for production planning in a mine-mill complex is presented. The system involves a mill receiving ore from a number of different locations, each with a unique mineral composition. The mill consists of several crushing and grinding circuits that function in series and parallel. Scheduling the flow of materials through the mill is complex due to constraints on throughput imposed by the millÆs design, the length of time material can be stockpiled on the surface, varying input mineral composition, and throughput targets for a range of output products.An optimisation model is used to create a set of campaigns (ore feed rates) over a given planning horizon under the assumption of deterministic mill throughput. A simulation model is used to evaluate the production plan under assumptions of stochastic machine failure and operational losses created by the need to cycle between input feeds. Campaign scheduling has two important implications for the simulation. First, during any campaign, multiple ore types may need to flow through the mill. However, the mill must be controlled to ensure that only one type of ore can be in a crusher, a grinder or a storage bin at any point in time. Second, as the mill switches from one campaign to another, the set of ores being processed may differ. Thus, the flow of ore through the equipment during a campaign changeover must be controlled to ensure that one or more of the ores from the current campaign can be completely eliminated before the ores from the new campaign are introduced.The simulation architecture employed for this project is Visual Basic for Applications (VBA) combined with MS-Excel as a user interface. A fixed step discrete event orientation is assumed as the simulation framework. A set of model constructs was built for the project with a specific Canadian milling operation in mind, but was designed to be representative of a broad class of milling operations. The constructs are implemented as class objects within the VBA structure, each with a number of properties and methods. The collection of VBA objects forms a composable modelling toolkit. These objects can be linked together by users, via MS-Excel, to represent a broad range of milling operations.

Sep 26, 2011

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

Underlain by and intruded into the sedimentary rocks of the Transvaal Supergroup the Bushveld Complex is the largest known layered intrusion in the world and contains one of the richest ore deposits on earth. It has been the world's major source of Platinum Group Metals (PGM) since the mid-1900s with Chromite and PGMs the two most economically important components of the Bushveld Complex. The lower group (LG), within the critical zone, consists of seven chromitite layers and it is within this sequence of chromitite layers, the most important target of the lower chromitite group is found, ie the LG6 chromitite unit. The LG6 chromitite unit consists of a chromitite duplex composed of the lower LG6 chromitite layer (Steelport seam), averaging 1 m thick, overlain by a 0.66 m waste parting and a thin 0.34 m thick LG6a chromitite layer (leader layer).Two mining methods are commonly applied in the Bushveld Complex to extract the LG6 chromitite layer package. One method consists of footwall development utilising rail bound equipment to gain access to the orebody and then extracts only the LG6 chromitite layer by means of hand held rock drills and scraper winches. The second method is the use of mechanised equipment to access the orebody on the plane of the ore utilising bord and pillar mining method, which extracts the full mineral resource, ie the LG6 and LG6a layers. Conventional narrow vein stoping is often selected due to the large conventional mining skills base found in South Africa, the perceived cost and dilution implications of utilising mechanised equipment, and the difficulties of using mechanised equipment at dips above 12¦. The driving factor for mechanised mining is the perceived ability to access the orebody quickly and inexpensively, and extract the entire mineral resource package (LG6 and LG6a) while limiting capital expenditure and improving safety.This paper investigates these two commonly applied approaches, highlighting the benefits and problems associated with the two approaches. Comparisons will be made of the two mining methods and recommendations given for the mining engineer to consider before selecting the appropriate mine design.

Dec 6, 2010