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By J S. J van Deventer

Geopolymerisation is a new technology that processes and transforms aluminosilicate minerals into mechanically strong and chemically stable products. In this investigation, minerals such as fly ash and kaolinite were used as the solid raw materials for geopolymerisation. Inorganic salts were added to the geopolymeric pastes to simulate ionic contamination during processing for building and construction applications. The resultant products were examined and characterised physically. It was found that the early strength development of geopolymeric pastes could be changed according to the nature as well as the extent of the contamination. At a small dosage, the effect of the contamination on the early geopolymeric system depended heavily on the nature of the artificial surfaces that were created in the geopolymeric solution through the addition of the chemical additives. For example, the samples containing MgCl2 and Mg(NO3)2 had shown the same yield stress developments due to the similar surfaces that were formed. The cations of these salts were expected to hydrolyse and form magnesium hydroxide precipitates immediately after the addition to the early geopolymeric systems. The calcium cations of CaCl2 also precipitated upon addition, but the nature of the surfaces of these hydroxides was quite different to those of the magnesium hydroxides and gave rise to different yield stress development. The samples that contained the insoluble salts (in water) demonstrated different yield stress development when compared to each other because of the different nature of the additive surfaces that were exposed to the geopolymeric solution. These results suggested that heterogeneous nucleation could be responsible for the change of the rheological behaviour upon inorganic salt addition. When the extent of the ionic contamination was large, the anions released from the insoluble salts (in water) changed the nature as well as the concentration of the geopolymeric solution and the setting processes were retarded. Oxides, in general, behaved very differently from other salts, indicating the uniqueness of the oxygen anions in a system rich in hydroxyl and silicate anions. The inorganic salt contamination in geopolymers did not show any significant signs of structural change according to the XRD diffractograms collected. The seven-day compressive strength was not lowered by the inorganic salt contamination and it could sometimes be beneficial to the product performance, for example, an increase of 20 MPa was induced by the addition of calcium oxide. Inorganic salts as chemical additives have demonstrated the potential to modify setting times of geopolymers without sacrificing much of the productsÆ strength and integrity.

Jan 1, 2000

By D Prior

The Australian mining industry is a significant contributor to the nation’s greenhouse gas (GHG) emissions, and like any industry, it must make efforts to reduce these. Medium- and long-term strategies will include the replacement of diesel engines with alternative energy sources, but what can be done in the short-term to reduce diesel consumption and hence CO2 emissions? Haul trucks are identified as the major contributors of CO2 emissions in the mining fleet and this paper focuses on firstly identifying what drives haul truck emissions and secondly, discussing what is the role of the Fleet Management System (FMS) in reducing these. A key enabler of this is having a robust fuel consumption model within the FMS, and I describe how this may be done. Besides novel approaches to incorporating fuel consumption (CO2) management into truck assignment algorithms, this paper also describes how the FMS can be used to implement and manage procedures and policies to reduce haul truck emissions.

Jun 22, 2022

By K B. Quast

Changes in feed size distribution can have significant effects in rod mill grinding. The product sizing resulting from wet batch milling of a tin ore showed little influence on fines production after truncating the feed at either the coarse or fine end. The addition of fine material caused a less amount of fines to be produced and a possible increase in grinding at coarse sizes, although this is complicated by the changing feed size distribution. The changes in feed size distribution caused no tendency for preferential grinding of the cassiterite.

Jan 1, 1998

By M Hopkins, A Mutale, A E. Vidal da Silva

The Cliffs Nickel Mine extracts a narrow near vertical nickel vein using a mining method of underhand bench stoping with paste backfill. In 2014, at a depth of 400 m below surface, the Northern block of the mine began to experience squeezing within ore development. At first the deformation was localised, within 30 m of the stoping front, but later became pervasive extending across the Northern block and resulting in a hiatus in mine production. The global mechanism is a progressive pillar failure, where the inter-level pillars in advance of the production front could no longer withstand the induced load and progressively yielded. The local mechanism of failure was observed as crushing of the massive sulphide ore and ‘punching’ of the pillars into the ultramafic hangingwall exhibited as floor and sidewall dilation and unravelling of the mafic footwall. The cause of the global mechanism was attributed to a combination of factors, including: high overall extraction ratio, small vertical pillar heights between ore development, high stress in relation to the low rock mass strength, shallow stope front angle, and insufficient ground support capacity. Following the progressive failure, the remnant rock mass conditions across the northern block were severely degraded, with numerous falls of ground that led to a reassessment of the mine plan. Recovery of the Northern block started in 2016 as a staged process. Development of the safe recovery work methodology involved a number of considerations, such as: production sequencing, development access design, ground support, and development of specific procedural controls. The Northern block was then broken into smaller mining precincts based on tactical factors such as location, ease of access, scale of rock mass damage and nickel content. A specific ground support standard and work methodology are employed, while cycle sheets are used to ensure quality and completeness of work. Large intersections showing signs of deformation have either been bypassed or treated using Rocprops to maintain stability during stope production. This approach has been successful in safely regaining access and restarting production in areas that had previously been removed from the mining reserve.

Mar 15, 2021

By K L. Brown

In the Waiotapu geothermal area only Champagne Pool, 109 ng/L, and Waiotapu Geyser, 7.6 ng/L, have dissolved Au concentrations greater than 5 ng/L and most springs have concentrations less than 2 ng/L. When Au concentration data are combined with other physico-chemical data from each spring including; pH, reduced sulphur concentration and temperature, the degree of Au saturation can be calculated. All samples sites except Champagne Pool, Waiotapu Geyser and the Artists Palette are under-saturated with respect to Au(s) by 1 to 3 orders of magnitude. This indicates that adsorption or co-precipitation or both are important processes depositing Au beneath hot springs. Deposition of Au by adsorption or co-precipitation beneath hot springs implies that dissolved Au may not have to reach saturation concentrations for ore to deposit. This interpretation is supported by the presence of substantial Au as sub-microscopic components within sulphide minerals in ore deposits and indicates depositional efficiency beyond that possible through precipitation of Au(s).

Jan 1, 2004

Study on New Tungsten Beneficiation Technological Flow Sheet of Shizhuyuan Polymetallic Mine

Sep 13, 2010

By F Clark, J T. Carswell

Ore definition for final stope planning is often a challenging prospect in underground (UG) gold mines which exhibit high geological and grade variability. Unlike the grade control (GC) scenario in an open pit (OP), the ability for the mining geologist to plan a sampling campaign which effectively characterises the underlying mineralisation is fraught with difficulty. UG sampling patterns are strongly clustered and typically not dense enough to characterise the spatial and statistical properties. Very commonly, sample volumes are not large enough to provide a reliable grade estimate of the surrounding rock. These factors critically affect our ability to accurately map out ore positions and estimate metal quantities.At Sunrise Dam, traditional UG sampling and modelling techniques have proven to be an unreliable strategy for successful stope planning and extraction. The problem was first observed during the final cut-back in the open pit for which the mineral resource model was constructed from UG diamond drilling. Open Pit grade control reconciliations were strongly positive for both tonnage and grade compared to the resource model. Underground workings missed significant quantities of ore which was laterally defined by open pit reverse circulation (RC) GC drilling. Upon examination it was realised that the cause of the problem was one of inadequate sample density and sample support, the implications of which potentially affected the entire UG mine.As part of a broader study into underground grade control procedures, detailed reconciliation of initial stope production from the GQ domain also pointed to inadequate sampling as a major constraint to effective grade control and reserve conversion.To overcome this deficiency, dense 115 mm wet RC grade control drilling and conditional simulation modelling has been successfully implemented with the intent to replicate the grade control process in the open pit. The increase in sample density and sample volume has proven to be a very effective tool for mapping out highly complex mineralisation. A marked improvement in stope definition, reserve conversion and Mine to Mill reconciliations has been demonstrated on the back of an innovative approach to UG grade control.CITATION:Clark, F and Carswell, J T, 2014. Using reverse circulation drilling to improve sampling in a complex underground gold operation – an innovative approach to underground grade control at the Sunrise Dam Mine, Western Australia, in Proceedings Ninth International Mining Geology Conference 2014 , pp 143–152 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

Study on Reasonable Mineral Processing Flow Sheet of Yunfu Low-Grade Pyrite Ores Low-grade ores in Yunfu Pyrite Mining Area were investigated, in order to find an economical, reasonable and environment-friendly mineral processing technology, which is of low consumption and high efficiency in pyrite recovering, which can ensure that the quality of pyrite concentrate product is eligible for sale and the sulfur content of the discharged tailings meets the national emission standards. A flow sheet with a classification, a jigging for coarse-grain minerals and a spiral chute separation for fine-grained minerals was adopted, and the sulfur grade and recovery of the pyrite concentrate is 35.50 per cent and 86.70 per cent respectively, while the grade of tailings is only 6.70 per cent.

Sep 13, 2010

By J Harris, M Shi, S Vink, P A. Kirsch

Across the life-of-mine, water is both an essential commodity to mining, and one of the most significant hazards. In Australia, a land of drought and floods, availability of water is a critical strategic risk for mine sites and neighbouring stakeholders, with both insufficient water leading to curtailed operations and contested space, and extreme water closing operations through flooding of mine sites, transportation infrastructure and unplanned regulatory restrictions. In addition to these major strategic risks, water must be addressed in operational risk management activities in many different ways.This paper develops a set of categories for classification of water risks based on academic papers from the water in mining literature. These categories are applied to media content analysis of articles in International Longwall News (ILN) (an online coal industry news site) obtained with the search terms ‘water’, ‘rain’ and ‘flood’. Identified risks are discussed within the context of the life-of-mine. The paper uses these same categories to analyse the treatment of water risks in a new coal industry risk management body of knowledge called RISKGATE (http://www.riskgate.org, Minerals Industry Safety and Health Centre, The University of Queensland). The discussion of water risks in both INL and RISKGATE is compared and contrasted to pinpoint opportunities (and a roadmap) for further development of a specific RISKGATE water module for site-based operations. The media review also identifies areas for development of RISKGATE expansion topic(s) that would address other strategic water risks, eg severe weather events.CITATION:Shi, M, Kirsch, P A, Vink, S and Harris, J, ?2014. Water as risk in mining – media analysis and the RISKGATE body of knowledge, in Proceedings Life-of-Mine 2014 , pp 205–218 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By P Nichols, C te Kloot, A Harrison

Ernest Henry mine (EHM) is a sub-level caving operation located in north-west Queensland, Australia. Located below a previously mined open pit, the underground operation ramped up production to 6.8Mt/a in 2017. The EHM ore body dips at 45 degrees to the South and therefore requires each level to “step out” from the level above as seen in Figure 1. Within this step out zone it is important to both maximise recovery and allow for efficient operation of the underground workings production to bring the level up to full production as quickly as possible. Throughout the step out design process, a combination of further defining the ore boundary, using lessons learnt from production performance on upper levels and the introduction of design improvements, has reduced the production ramp-up time, decreased costs and increased recovery for a single level at EHM. CITATION: Nichols, P, te Kloot, C and Harrison, A, 2018. Case study – Ernest Henry Mine: designing step out zones in an inclined sub-level cave, in Proceedings Complex Orebodies Conference 2018, pp 53–54 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By A Harding, M Chappell

Precast concrete segmental linings have enjoyed widespread use around the world, and are the lining type of choice for tunnels constructed using a shielded tunnel boring machine. However, there is significant variation in the design of such linings from one country to the next in such areas as materials, geometry, fixtures and fittings, waterproofing and reinforcement to name but a few. This arises because the speed at which the technology has developed within some countries and regions has sometimes outstripped the transfer of such technologies to the rest of the world.This paper provides some insights into the variations in lining design in different parts of the world with the aim of providing designers and constructors alike a reference for the different methods adopted. It provides a context for these developments by briefly summarising historical reviews of this subject before looking at some of the developments around the world over the last 15–20 years. The developments are presented with some reference to the reasons for implementation, and the advantages and limitations commented on. Following on from this description of the state-of-the-art, the authors also provide their own views on what developments we may see in this area in the near future.CITATION:Harding, A and Chappell, M, 2014. Precast concrete segmental tunnel linings – the state-of-the-art, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 257–266 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By R J. Goldfarb, A B. Christie, D I. Groves

Small orogenic gold deposits have the same deposit-scale geological and geochemical features as those that characterise giant orogenic gold systems (>16 Moz Au). Therefore, a broader-scale approach is needed to identify the critical controls on giant deposits and their disproportionate distribution throughout time and space. Ages of giant gold systems cluster around well-defined periods of lithospheric growth at continental margins, and it is orogen-scale processes during these Late Archaean, Early Proterozoic and Phanerozoic times that determine gold endowment of a province.   A critical factor for giant orogenic gold provinces appears to be asthenospheric upwelling at the time of gold mineralisation to most effectively transfer the thermal energy required to initiate and sustain high hydrothermal fluid flux. The extent of this fluid flux should be related to thickness of the lithosphere beneath a province at the time of gold mineralisation, such that giant gold deposits are much more likely to develop in orogens with oceanic or thinned continental lithosphere. A proxy for the latter is likely to be a short premineralisation crustal history such that thick subcontinental lithospheric mantle was not developed. Conversely, orogens with protracted premineralisation crustal histories are more likely to have a thick subcontinental lithospheric mantle, which is difficult to delaminate and, hence, such provinces will normally be poorly endowed. The nature of the lithosphere also influences the intrinsic gold concentrations of potential source rocks, with back-arc basalts, transitional basalts and basanites enriched in gold relative to other rock sequences. Thus, segments of orogens with thin lithosphere may be defined by conjunction of giant-scale fluid flux through gold-enriched sequences.   Although the nature of the lithosphere plays the crucial role in dictating which orogenic gold provinces will contain one or more giant deposits, the precise siting of those giants depends on the critical conjunction of a number of province-scale factors that control fluid conduits, traps, and seals in tectonically and lithospherically suitable terranes within accretionary orogens.

Jan 1, 2005

By J de Witte

When used in suitable ground conditions, rock bolts can have advantages over other permanent tunnel lining solutions. Permanent rock bolts offer flexibility in tunnelling profile and rapid rock bolt installation can enable time and cost savings. There are also disadvantages when considering the suitability of rock bolts for permanent support installations. These generally concern achieving the specified durability requirement over the specified design life. By investigating alternate approaches to rock bolt installation, quality assurance (QA), monitoring and design life it may be possible to alleviate some of these concerns.The design and construction benefits that can be realised through the use of rock bolts are primarily related to reducing project program time. This time reduction could be realised if rock bolts are considered as a permanent solution, with the installation being completed as a part of the primary excavation cycle. Any reduction of the program could allow direct and indirect cost savings and in the case of a major project, allow the revenue stream to be realised earlier.Currently ambiguity exists where the treatment of rock bolts as permanent support components is inconsistent with that of (often identical) ground anchors, as utilised in stabilising cut and cover structures. The ground support design process, implementation and testing are generally similar, though the acceptance of rock bolts as long-term support elements is treated differently to ground anchors in technical specifications.This paper discusses some of the benefits available through the use of rock bolts. It offers different solutions to the concerns surrounding durability, including alternate approaches to installation, Quality Assurance practices and monitoring solutions. The selection of an alternate design life is also investigated as another means of alleviating concerns around long-term durability. The paper will also provide an indication of savings that could be expected through the use of rock bolts as part of a long-term support system.

Mar 8, 2011

By S Marshall, A Fowler

The Augusta underground mine at Costerfield in Central Victoria has been in operation since mid 2006; however, AGD Operations Pty Ltd have explored and undertaken open pit operations in the area for over 20 years. The high-grade, narrow gold-antimony orebody is being mined using both mechanised and hand-held methods, to produce up to 70 000 tonnes per annum at ten grams per tonne gold and six per cent stibnite. AGD Operations Pty Ltd processes the ore on site using gravity and flotation to produce two products; a concentrate which is sold to Chinese smelters and a gravity concentrate which is refined off-site. The circuit achieves up to 30 per cent recovery of gold from gravity methods. There are many challenges in the underground mine, including an orebody with an average width of 300 mm, very poor rock mass conditions in the host rock and variable dips in the ore along strike, between 45¦ and 90¦. The upper levels of the mine have been developed ready for stoping; however, their depths range from 20 m to 70 m below surface in both oxide and transitional material. A major fault structure consisting of mud has been encountered underground and is associated with the orebody causing very poor ground conditions, water inflow and requiring additional reinforcement. The northern limit of the mine is defined by the proximity of historical workings in the South Costerfield mine, which is being continuously dewatered.

Jan 1, 2008

Reason Analysis of Impurity Containing and Technology Discussion of Quality Improvement for Low-Quality Iron Concentrate

Sep 13, 2010

By M Scoble

This paper addresses the importance of collaborative approaches to resolving future mining challenges. It attempts to provide some insight into understanding the theory, measurement, mapping and management of collaboration. This is related to the design and planning for successful research and educational initiatives. Reference is made to Canadian and global case studies and personal experiences.

Nov 22, 2011

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 L Thorburn

In 2009, the Queensland Government developed a series of amendments to environmental authorities (EAs) for mines throughout the Fitzroy Basin in response to studies that assessed the cumulative impacts of mine water discharges in the basin. One of the key amendments was the requirement for all mines in the Fitzroy Basin to develop and implement a receiving environment monitoring program (REMP). The intent of the REMPs was to provide baseline information on the condition of the receiving environments of the mines and any impacts resulting from release of mine-affected water. Since this time, the requirement to complete a REMP has been incorporated into new or revised EAs for mines (including metalliferous mines) in other regions, as well as for other industries that discharge to natural watercourses (such as coal seam gas). This paper discusses the approaches that can be used to incorporate biological monitoring and direct toxicity assessments into REMPs. It highlights the importance of collecting biological data using sound experimental design principles to investigate whether releases resulted in environmental harm; and the use of monitoring data, coupled with direct toxicity assessments, for setting more realistic, site-specific trigger values and release limits (compared to the default guidelines such as Australian and New Zealand Environment and Conservation Council (ANZECC), which may not be appropriate to the region). Implementation of a robust REMP can maximise outcomes for both the proponents and the environment.CITATION:Thorburn, L, 2013. Receiving environment monitoring programs - making the most out of biological indicators and direct toxicity assessments for monitoring of aquatic ecosystems, in Proceedings Water in Mining 2013 , pp 143-148 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

By H Tran

Local communities are undertaking an increased role in mine project decision making processes, associated with growing pressure and expectations from regulators, financiers and the general public. This is particularly evident in international projects within developing economies. Environmental and social issues are often complex. Solutions demand difficult choices and trade-offs between sustainable development dimensions: economic growth, social equity and environmental integrity. Proactive stakeholder engagement can play a critical role in assisting decision-makers in determining the operational reality of sustainable development by jointly exploring project trade-offs between proponents and affected stakeholders. Good stakeholder engagement has other potential benefits, ranging from reduced financial risk due to regulator delays, legal disputes or negative publicity to increasing market share through good public image. Approaches to consultation and disclosure have changed from short-term regulatory based focuses, to longer-term, strategic tools for relationship building, proactive risk management and new business identification. Approaches to consultation form a significant opportunity to contribute to overall social sustainability. This paper discusses, based on authorsÆ experience, the broader concept of stakeholder engagement and its contribution to social sustainability of the mining industry. The focus is on key considerations for an effective stakeholder engagement. Three case studies outline how broad based, proactive stakeholder engagement can contribute to improved operation and overall sustainability. The case studies include: a greenfields project in Ghana; a long-term mine in Australia; and an open-pit mine in Vietnam.

Jan 1, 2009

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

Jan 1, 2005