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By Beamish B. B

In this study, a systematic examination of the scale and variety of micro-structures in coal using Scanning Electron Microscopy (SEM) has been carried out, using coal samples of differing stages of coalification from the Bowen Basin and New Zealand. SEM provides detail of various micro-structural features and shows that a variety of micron-sized fractures and cavities are present in coals. These are differentiated into three pore types: fracture porosity, phyteral porosity and matrix porosity. Fracture porosity is generally associated with bright coals (although it has been shown that micro-fractures are present in maceral fragments from the dull coal layers). Characteristically the macro- and micro- fractures form a continuous structural fabric through the bright coal layers and thus make a significant contribution to overall permeability. The macro- and micro-fractures appear to have been formed during the process of coalification rather than being formed due to shrinkage during methane extraction, as most of them are infilled with secondary minerals. In contrast, phyteral and matrix porosity is associated with the dull coal layers that are composed of plant fragments or a heterogeneous mixture of macerals. Like the macro- and micro-fractures, the continuity of the observed cavities suggest that these too are a significant contribution to overall permeability, and therefore play a major role in the transmissibility of methane at a level between diffusion at the micropore level and laminar flow at the macro-fracture level. Due to different spacing, orientation and persistence of individual fractures and cavities, the rate of methane transmissibility through a coalseam will vary according to coal rank, coal type and the organic precursors from which the coal was derived. This is important as a knowledge of the micro-structure system and its relationship to coal type and coal rank, plays an important consideration in: a) gas drainage modelling, b) enhancing permeability by inducing fractures and c) predicting the occurrence of outbursts.

Jan 1, 1991

Project Sustainability Assessment - Matching Method to Enterprise Size Sustainable development requires managing natural resources, including minerals, in a way that is conducive to long-term wealth creation and the maintenance of capital (natural, social, human, economic and physical). One aspect of the minerals sustainability discussion focuses on replacing depleted mineral capital with other forms of capital so as to ensure that the contribution of a mineral project is net positive over its life. Another, equally important, aspect focuses on selection of projects and technologies that contribute to the achievement of a variety of sustainability objectives, such as environmental protection, efficient use of resources, water and energy, worker health and safety, and the equitable distribution of risks and benefits within and across generations. Technical feasibility and relative economic performance remain necessary decision criteria for mineral investment decisions, but they are no longer sufficient. Enterprises, regardless of size, are now confronted with the challenge of comparing investment alternatives based on a new, broader set of criteria. The field of integrated sustainability assessment (ISA) emerged in response to this changed social and business environment. ISA is a structured process for examining the economic, social and environmental impacts of a project or technology. The purpose of an assessment can be broad, a strategic review of corporate behavior for example, or quite narrow, input to a specific decision process such as the selection of a piece of equipment. There are numerous methods and analytical tools available to conduct ISAs and selection of the most appropriate for a given situation will depend upon temporal focus (retrospective to prospective), decision context (strategic, tactical or operational), and phase of the assessment process (problem structuring, analysis, resolution, ex post review), among others. Selection also depends upon enterprise size and the attendant availability of financial and human resources. Large multi-national firms often undertake complex, data intensive sustainability assessments, in part because the projects they are involved in are multi-faceted, long term, and require significant financial investments. Small and medium sized enterprises are seldom able to commit the same level of resources to an ISA, and if the projects they undertake are less complicated, a time consuming and detailed assessment may be unnecessary. Regardless of enterprise size, the tangible and reputational benefits of conducting as ISA must exceed the actual monetary cost of doing so. This presentation will provide an overview of available ISA tools, categorising them in terms of their data requirements, methodology, outputs and applicability in various decisions contexts. Distinction will be drawn between situations where reasonable approximations of project impacts can be expected to provide an adequate amount of information and those for which more detailed analysis is essential. Finally, ISA strategies that have been successful and cost effective at different scales of business enterprise will be identified. This is an abstract only. No full paper was prepared for this presentation.

Sep 13, 2010

By J Zhang, L Klemettinen, A Jokilaakso, J Biswas, J Partinen, H O’Brien, A Klemettinen

Waste lithium-ion batteries (LIBs) are important secondary sources of many valuable materials, including Critical Raw Materials (CRMs) defined by the European Union (EU): lithium, cobalt, manganese, and graphite. Additionally, LIBs typically contain nickel and copper, which are classified as Strategic Raw Materials for EU since 2023. In recent years, great effort has been made to develop efficient recycling processes for waste LIBs. Pyrometallurgical processes have been essential in industrial production of metals for many decades. These technologies are relatively mature, with high adaptability for different raw materials. Pyrometallurgical treatment in LIB recycling typically involves the use of smelting processes, in which waste batteries are heated above their melting points and metals are separated through a reduction reaction in the liquid phase. Through this recycling route, cobalt, copper, and nickel can be efficiently recovered in the form of a metal alloy, whereas lithium and manganese are lost in the slag phase. The goal of this work was to increase the recoveries of valuable battery metals through a combination of hydro- and pyrometallurgical unit operations. First, industrial Li-ion battery scrap underwent a selective sulfation roasting stage, where the aim was to transform LiCoO2 and Mn-oxides into Li, Co and Mn sulfates. After roasting, the battery scrap was leached in distilled water with a solid to liquid ratio of 100 g/L at 60°C and recovered 95 per cent of Li, 61 per cent of Mn and 35 per cent of Co. After leaching, the solid leach residue was mixed with industrial Ni-slag and biochar, followed by reduction at 1350°C in argon atmosphere. The high-temperature smelting experiments were conducted as a function of time (5–60 mins) to investigate the reduction behaviour of battery metals. The results show that Co and Ni from the slag and leach residue can be efficiently recovered in the slag cleaning stage.

Jun 19, 2024

By Read T. A

THE Broken Hill South Ltd. is one of ten companies operating on the Broken Hill lode (See Fig. 1). It has two leases-Blocks 7 and 8-of a total length of 2250 ft. on strike of lode.From the surface to 425-ft. level the ore was found principally in the form of carbonates and high-grade friable sulphides. Below the 425-ft. level the ore is found in the form of compact sulphides. The ore-bodies found in the South mine may be broadly divided into two classes...

Jan 1, 1921

Over a century ago the first ship designed solely for carrying a bulk cargo was launched. This vessel, the "John Bowes", with a deadweight of 660 tonnes was a single decked ship with machinery and accommodation aft. As such she was undoubtedly the fore- runner of the bulk carrier of today only some two hundred and fifty times smaller. Whilst the "John Bowes" pioneered the present accepted mode of transporting the bulk com- modities of the world, it is unlikely that her cargo was either loaded or discharged as quickly as that of a 150, 000 tonner of today. Two decades ago the bulk carrier was beginning to feature in the bulk handling ports of the world. Cargoes of iron ore previously carried in the 'tween deck vessels of the Empire type and Second World War Liberty ships began to be poured into the unrestricted open holds of bulk or ore carriers. The size of vessels catering for this relatively new innovation has rapidly grown to pass the 150, 000 deadweight tonne mark, but only in the last few years. The growth from now into the future is not simply one of ship size evolution. Neither is it a function of the depth of water available at ports. It is in fact a function of a number of features such as ports, loading and unloading facilities, ship trading characteristics, length of voyage and total economies of the transport task from supplier to destination.

Jan 1, 1973

By E Widzyk-Capehart, C Hölck Teuber, S Steffen, V Rivero, O Fredes, E Sanchez, I Pedemonte, N Gonzalez

This paper summarises the research, development and initial application of a sensing platform that has the potential to monitor subsurface deformations, pore pressure and other variables simultaneously to gain a better understanding of rock mass behaviour. The platform is based on Networked Smart Markers (NSMs) devices, which, with their ability for wireless communication between individual sensors and the possibility of real-time data acquisition and processing, will assist in the development of predictive tools to better assess rock mass behaviour.A good opportunity to implement this technology is in the specific application of transitioning from an open pit mine to an underground caving operation. One of the key elements to maintaining the mining business during such a transition is having a good understanding of the unique geotechnical conditions of mutual influence created during the open pit to underground interaction. The knowledge acquisition will require the implementation of a robust platform for geotechnical monitoring, which could be enhanced by incorporating the NSMs. The integration of sensors within the NSMs would enable the collection of additional data about rock mass behaviour (ie caving propagation and crown pillar fracturing), which could be used to improve the management of mining operations and, specifically, allow the development of reliable predictive tools based on the data collected.CITATION:Widzyk-Capehart, E, Hölck Teuber, C, Fredes, O, Rivero, V, Sanchez, E, Pedemonte, I, Gonzalez, N and Steffen, S, 2016. Understanding rock mass behaviour through the development of an integrated sensing platform, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 275–284 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By A Valero, G M. Mudd

There is active debate and research around the most suitable indicators to assess the sustainability of mining. The most common approach is to report a range of data for a given mine site (or less preferably, a company total), such as inputs, outputs, benefits and potential costs. The most popular protocol in use (and growing rapidly) is the Global Reporting Initiative (GRI). However, these measures are numerous and still do not allow a single over-arching indicator to be developed. Other measures, such as known mineral resources over time, do not account for critical challenges such as declining ore grades, increasing wastes and poorer quality ores or more difficult mineralogy. By adopting a thermodynamic approach to sustainability, through the concept of æexergyÆ, it is possible to incorporate into a single measure the effective quality of mineral resources. Exergy involves the assessment of the minimum energy costs involved in producing a mineral resource with a specific chemical composition and concentration from common materials in the environment. The exergy of a mineral resource is evaluated from mineralogic composition, concentration (or ore grade) and, of course, quantity, by multiplying the unit exergies with the tonnes of the resource produced (or consumed). Since exergy is a thermodynamic quantity (ie energy or joules), it is additive across different minerals, such as iron ore to gold to copper or even oil and gas or coal û making it an ideal indicator to assess mineral resource sustainability at the industry scale rather than the individual mine scale. This paper briefly outlines the theoretical basis for exergy, and then presents a range of commodity case studies showing the application of exergy to the Australian mining industry. Overall, the usefulness of exergy is clearly demonstrated for use as a broad indicator of the sustainability of mineral resources at the national or even global scale.

Jan 1, 2009

In November 1986 the Australian Minerals and Energy Council (AMEC) endorsed an "Australian Code for Reporting Identified Coal Resources and Reserves" for use by the Federal and all State Governments. Before this endorsement there were six different coal codes in use in Australia. The code is broad in nature to accommodate the wide range of coal deposits in terms of rank, quality and geological environment, that are present in Australia. In the code, Resources refer to all of the coal in situ which may have potential for use and the various categories indicate the level of confidence of the assessment. Reserves are those Resources which are planned to be mined and for which such planning has been undertaken. Only minimum guidelines are set by the code and the onus is on the estimator to state clearly the criteria used in any Assessment.

Jan 1, 1987

The Goonumbla district of central-west New South Wales, Australia, hosts four significant porphyry Cu-Au deposits that contain a combined probable ore reserve of 71.7 million tonnes at 1.2 per cent Cu and 0.5 g/t Au. Mineralisation in the Goonumbla deposits is associated with narrow, pipe-like intrusions of quartz monzonite porphyry, in which several intrusive phases have been recognised. Five textural characteristics have been used to distinguish the various intrusive phases recognised in the Goonumbla porphyry deposits: (1) phenocryst abundance; (2) nature of the groundmass; (3 and 4) proportion and mineralogy of the mafic and non-mafic phenocrysts; and (5) the presence or absence of anhedral quartz grains in the groundmass. In addition, each intrusive phase is classified according to its estimated original quartz, alkali feldspar and plagioclase contents. Features common to all of the intrusions are that they contain two types of plagioclase and two or three types of K-feldspar phenocrysts in variable proportions. Most of the intrusions also contain apatite micro-phenocrysts. The groundmass textures range from aphanitic through granular to euhedral K-feldspar in a quartz matrix. With only one exception, all of the intrusive phases recognised are either quartz monzonite porphyry or mafic (>5 per cent mafic minerals) quartz monzonite porphyry. The exception is a biotite - phyric monzodiorite, which occurs in the basal portions of one of the deposits. Textural variants of intrusive phases at Goonumbla have been investigated to establish whether specific combinations of characteristics indicate mineralised intrusions, while others suggest barren ones. Some correlations between intrusion types and Cu and Au grade have been recognised. The most important textural characteristic that relates to high grade mineralisation appears to be the low proportion of mafic minerals, because the quartz monzonite porphyry intrusions hosting most of the mineralisation in the two deposits studied contain

Jan 1, 1999

As the title indicates the central themes discussed in this contribution are sustainable development, information systems, and extractive industry. More specifically, the objective is to present a prototype for the systematic generation of extractive industry (henceforth: EI) û specific sustainability information. The paper begins with the authorÆs viewpoints on the core notions of sustainability, and development, as well as their relationship to information. These set the stage for the introduction of the information system (IS), as well as the follow-up sustainability information system (SIS) extractive industry sustainability information system (EISIS) concepts and related discussions. The paper continues with a second part, in which, efforts to research and develop an EISIS prototype are described. First, the team is presented. Second, the systemÆs aim and target groups are briefly discussed. After, an articulated overarching EISIS conceptual model emphasising capital accumulation, and service flow concepts û is presented. This is followed by a detailed description of the assembled prototype with a focus on data and information generation. The formulation of data generation, storage and transmission processes, as well as its use in sustainability interpretation rules and their embedment in the conceptual model is made with respect to monetised stock and flow parameters, measured in the appropriate dimensions. In the third part, the author presents and discusses the results of a first round of prototype experimental development in three major EI firms. First, the system observation, and data analysis protocols are described. Second, a review of protocol implementation, and respective results, is made. Finally, the overall performance of the proposed prototype, and development process issues are discussed, before suggesting areas for improvement and future research. The paper ends with a conclusion in which the author provides a retrospective balance of the æknowledge creation projectÆ, as well as a prospective outlook for research in this field; before acknowledgements are made and references provided.

Jan 1, 2009

Can mining promote sustainable development? What is sustainable development? Is sustainable development good for corporate sustainability? Does it work in practice? If so, is it good for business? This paper does not seek to provide definitive answers to these issues. Rather, it is presented in the interests of sharing information and contributing to the pool of collective experience. The discussion will draw on the experience of Placer Dome in Papua New Guinea (PNG). Sustainable development means development that is maintained at a steady level without exhausting natural resources or causing ecological disturbance. The term æsustainable developmentÆ is often linked to the concept of ecological equilibrium, development that is self-replenishing. While its essential meaning remains the same, in practice, and for todayÆs complex and industrial world, different people will interpret sustainable development in different ways. Given the dynamics of development and the competing social, political and economic interests, sustainable development must be seen from a much broader perspective. This is the point that this paper will attempt to make. Mining, an activity that uses non-renewable resources, can promote sustainable development. The 1987 Brundtland Report (also known as the Report of the World Commission on Environment and Development), defines sustainable development in a broader manner - as development that meets the needs of the present world without compromising the ability of future generations to meet their own needs (Elkington, 1997). This definition calls for inter-generational equity in the development and use of resources by many organisations, including multinational corporations. Corporate sustainability, on the other hand, is about developing strategies that guide a corporation to stay alive and, more importantly, to stay ahead of its competitors. It is basically about survival in a competitive social and commercial environment. In a corporate world, profitability is survival. In this context, corporate profitability, the main ingredient of corporate sustainability, is important for sustainable development. Without profits, corporations will find it difficult to practice sustainable development or indeed any development. Sustainable development can integrate mining activities with the rest of the community, add value and, in the long-term, profits to the bottom-line. Ultimately, sustainability will force corporations to adopt strategies based on a longer time scale to survive. In the mining sector, corporate sustainability depends on a close relationship with all stakeholders, particularly landowners for whom sustainable development is critically important. Increasingly, there is an acceptance of the view that success is not achieved simply through competition in price, cost and technology but, more importantly, through creating social infrastructure which support community ethics, norms and values essential for trust and partnership. Needless to say, mining companies that engage in appropriate community-based development in support of inter-generational justice recognise the true value of sustainability. This is sometimes called the æhuman sustainability approachÆ which underlines the critical significance of trust in relationships with stakeholders and continuous improvement of corporate capabilities directed towards the future (Dunphy and Griffiths, 1998). In the long-term, such development will enhance corporate public image and acceptability. In practice, both concepts can be built on the principles of economic viability, environmental quality and social justice -what, in todayÆs parlance, is increasingly becoming known as the ætriple-bottom-lineÆ approach to business (Elkington, 1997). Underpinning this approach is a process of continuing dialogue and co-operation between governments, non-government organisations (NGOs) and business.

Jan 1, 1999

Two key elements in the design of a pastefill or high density hackfill system are the preparation of the backfill material and its distribution underground. This paper examines these two areas. Owing to the essentially impervious nature of total mill tailings, preparation of pastefill and high density fill from current tailings involves a physical dewatering process. There are currently three methods available for this process: I. Vacuum or pressure filters. These represent the 'traditional' approach to the preparation of pastefill. 2. Paste production storage mechanism. This is a thickening/storage mechanism developed with the specific objective of producing paste/high density backfills. 3. Fluidization. This system utilises silos fitted with simple dewatering devices and nozzles. Recently developed by CANMET, it provides the simplest and most economical approach. This paper describes and compares the three preparation methods, from a practical and an economic point of view. Once the pastefill/high density fill has been prepared and binder added, the backfill must be distributed underground into the stopes. A fundamental factor in the design of a distribution system is the rheology of the material- No two materials will exhibit the same properties, and a sequence of rheological and related testing is required prior to the completion of the design of the underground distribution system. This paper covers the testwork normally required and discusses the fundamental design parameters of pastefill distribution systems. The final section of this paper summarises the use of pastefill at three mincsin Canada.

Jan 1, 1998

No paper available.

Jan 1, 1996

By Woodcock J. T, Zhu T, Sparrow G. J

A lead-zinc-pyrite flotation middling was pressure oxidised to give residues containing iron hydroxy sulphates (a mixture of basic iron sulphate (BIS) and a hydrated iron sulphate (HIS)) and lead sulphate. Direct thiourea leaching of this residue gave over 90 per cent extraction of gold and silver, but thiourea consumption was high (56 kg/t) because of soluble iron(M) in the residue. Attempts were made to decrease the thiourea consumption by removing the water-soluble iron(M) or reducing it to iron(II). Water washing of the pressure oxidation residue removed most of the hydrated iron sulphate but little of the basic iron sulphate. Iron removal was only 12-20 per cent, depending on the number of washes, from one sample which was low in HIS, and 40-45 per cent in another which was high in HIS. Iron extraction was not appreciably increased by using dilute sulphuric acid (with or without additions of sodium sulphite), dilute phosphoric acid, or sodium chloride solution (150 g/L NaCI). Direct thiourea leaching of the water-washed residue gave over 90 per cent extraction of gold but only 49 per cent of silver, with a thiourea consumption of 27 kg/t. However, the application of a water wash followed by reduction of dissolved iron(III) with sodium sulphite in the presence of thiourea, and then thiourea leaching resulted in over 98 per cent extraction of gold and silver for a thiourea consumption of 26 kg/t.

Jan 1, 1991

By Z Li, Z Yan, T Htet, S Zhang

During the pyrometallurgical processes, a substantial quantity of high-temperature ironmaking and steelmaking slags, generated at temperatures ranging from 1400 to 1600°C, is wasted, as the heat contained in these slags is released into the environment during the tapping process without effective utilisation. On the other hand, a significant amount of energy is required to reheat the cold materials for the manufacturing of glass and mineral-wool, often necessitating the addition of high-silica materials to facilitate the production process. In this study, an innovative approach is presented to harness the heat present in molten metallurgical slags to directly produce new raw materials for glass and mineral-wool manufacturing while simultaneously reducing energy consumption and mitigating CO2 emissions. The theoretical amount of waste glass that can be effectively added in the process has been estimated via thermodynamic calculation. Experimental assessments were conducted to examine the impact of high-silica waste materials on the dissolution, melting and fluidity. Potential recipes for glass and mineral-wool manufacturing were suggested and an assessment of the energy savings, and reduction in CO2 emissions with manufacturing of glass and mineral-wool using this innovative approach were included. It was determined that the processes could lead to a reduction of over 26 kg of CO2 emissions per 100 kg of new material used, primarily due to the utilisation of heat from slag and the accelerated smelting process.

Aug 21, 2024

By A Parry, C Fitzmaurice

After conducting laboratory ore sorting testwork on samples of a low grade nickel ore stockpile at Western Areas’ Flying Fox nickel mine, a mobile crushing, screening and ore sorting plant was located adjacent to the stockpile. An initial two month trial of the ore sorter program proved successful and was extended to process the entire Flying Fox low grade stockpile in a further four month campaign. A total of 167 660 t of low grade ore was processed, providing highly upgraded feed trucked 26 km to the Cosmic Boy concentrator. A more than three-fold grade increase was achieved on ore sorter accepts. The moderately upgraded fines that by-passed the mobile ore sorter were also subsequently blended into plant feed. This paper describes the mineralogy of the Flying Fox low grade ore, the mobile ore sorting campaign and provides some commentary on the economic and environmental benefits achieved in the ore sorting campaign. The ore sorting campaign demonstrated the benefits of being able to utilise mobile ore sorting equipment temporarily located adjacent to sub-economic low grade stockpiles in order to effectively treat these stockpiles and produce viable plant feed.CITATION:Parry, A and Fitzmaurice, C, 2018. The upgrading of low-grade nickel ore stockpiles at Western Areas Ltd Forrestania operations, using a mobile ore sorting plant, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 541–550 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By D Kepert, C Simpson, D Edwards

Channel iron deposits (CID) currently supply over 40 per cent of the seaborne iron ore trade out of the Hamersley Province. The two well documented producing systems (Robe and Marillana palaeochannels) were both discovered during early reconnaissance mapping principally by BHP Billiton (BHPB) and Geological Survey of Western Australia (GSWA) during the mid 1950s to early 1960s. Both crop out extensively over the majority of their length. Hot on the heels of Fortescue Metals Group 2004 - 2005 discovery of approximately 2.6 billion tonnes (Bt) of undercover iron ore mineralisation in the Chichester Range, the Fortescue Exploration Department turned its attention elsewhere throughout the Hamersley Province. Reappraisal and analysis of publicly available data and ground truthing of developing models led to the recognition of the Solomon palaeochannel system. Subsequent exploration defined a world-class Resource of some 1.9 Bt of iron ore mineralisation of which the great majority is buried CID. Apart from the Marillana CID system, the Solomon region is the only major CID with significant tonnes of sub two per cent alumina CID with over 500 Mt delineated to date. Exploration has also outlined significant supergene bedded and detrital iron ore mineralisation. Ongoing drilling is expected to increase the resource base both in terms of tonnes and confidence. This paper outlines the principal contributing factors which led to the discovery of the Solomon CID and compares its geology with the Robe and Marillana palaeochannel systems.

Jan 1, 2009

By Kuzmitch O, Morozov A

The main direction in the mechanisation in the mines of the Donbas and the USSR is long-face technology with complexes on the base of hydraulic supports. On the base of the 30 year old experience of exploitation of the coal clearing systems the serious data about the behaviour of the contained rock, display of underground pressure 'on longwalls and preparatory workings have been accumulated. Exploitation works in mines of the USSR are carried out at different depths: from 1000m to 1200m. There are 26 mines in Donbas, which exceed the depth of 1000m. It is the mines of Donbas, where is a rich experience of the exploitation of coal seams in various conditions. Besides, there are wide variations on the factors of the extraction thickness, depth of seam, angle of dip, occurrence of gas dynamics and others. In many scientific establishments, and in Donetsk Polytechnical Institute also, there are scientific research/results, which can be of interest for the coal mining countries.The volume of coal mining from longwall system-mechanised walls in Donbas became stable at the end of the 70s at level of 70 percent. All the efforts to increase this level have not given any notable results, not saying about the technical-economical data, which gradually deteriorate. It shows that positive progress in using the technology for the long walls is over and it is necessary to find new ways of mechanisation of coal winning.

Jan 1, 1991

By G P. Bates

The rationale for the design of the Emergency Egress (escape andentrapment) strategy for one underground metal mine has beenpreviously described (Brake, 1999). Two of the key conclusionsfor this mine, which is equipped with 30 minute oxygen-generating self-contained self-rescuers (SCSR), were the need to ensure no person is ever more than 750 m from an emergency refuge station (ERS) and that it could take up to eight hours to rescue workers from undergroundå. These conclusions were based on a number of considerations including the non-availability of a credible, æpersonalÆ entrapment procedure at the workplace, the duration of self-contained self-rescuers when used for travel, the need for rapid æclearingÆ of mine personnel to effectively and safely target mine search and rescue resources and the maximum time to either put a fire out, or to rescue affected personnel. As there is no Australian standard for refuge stationsç (or for self-rescuers), this paper follows with guidelines for the location and specification of both fixed (permanent) and relocatable Emergency Refuge Stations (ERSs) that may be applicable to other underground Australian metal mines.

Jan 1, 1999

By B Lumsden

During periods of high metal prices and strong metal demand tailings retreatment can be economic. Most tailings retreatment operations are technically challenging, low margin operations, because the easily recovered mineral has already been removed, therefore, process improvements can potentially yield large economic benefits. The Hellyer tailings dam was owned by Intec Ltd and contained 10.9 million tonnes grading 2.8 per cent zinc, 3.0 per cent lead, 88 g/t of silver, 0.16 per cent copper and 2.6 g/t gold. In November 2006 the Polymetals Group, as operator, restarted the Hellyer plant to retreat these tailings. Within a few months the operation had stabilised and Polymetals was meeting budgeted targets of throughput, metal recovery and concentrate quality. Polymetals and Intec then investigated methods that would improve the metallurgical result for this difficult to treat tailings. Since the tailings are fine-grained with 80 per cent <45 ¦m, magnetic aggregation of the paramagnetic sphalerite was evaluated. Magnetic aggregation of an oxidised tailings feed has not been tested before, nor had the technology been available when Hellyer ore was originally processed. Extensive statistical test work showed magnetic aggregation of the sphalerite fines in the zinc cleaner circuit increased total zinc recovery. The increase in the mean zinc recovery with magnetic conditioning was 3.63 per cent, at a statistical level of confidence of 97.8 per cent, and at the same mean zinc concentrate grade.

Jan 1, 2009