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By D Craw, P V. Angus

Gold mineralisation at Macraes occurs as late quartz-carbonate veins within a body of sheared and hydrothermally altered Otago Schist, the Intrashear Schist. The alteration is characterised by the presence of rutile and the absence of epidote and titanite, indicative of an alteration fluid containing >10 mol per cent CO2. In areas of high strain, a fabric of black microshears develops, gradational to mylonitic cataclasite in the high strain zone adjacent to the hanging wall of the duplex shear zone. The microshears contain hydrothermal graphite, inferred to have been deposited from a methane-rich fluid. The mylonitic cataclasite is characterised by abundant pyrite, the absence of albite and extreme grain size reduction. Gold recovery in the CIL processing plant at Macraes can drop to 50 per cent or lower for some unfavourable ore types. Preg-robbing by a component in the ore, possibly graphite, was suspected as the cause. Mylonitic cataclasite was identified as the lithology responsible for the poor recoveries, with the capacity to bind about 30 ppm of gold in the leach tanks. A program of detailed geochemistry and quantitative grain-size measurement using Coulter analysis was undertaken to identify specific mineralogical factors associated with preg-robbing. The results indicate that pyrite, graphite, and extreme grain-size reduction are the factors associated with highly preg-robbing ores at Macraes. The evolution of the mylonitic cataclasite is accompanied by strong potassium enrichment, as muscovite, and depletion in sodium as albite is removed. This suggests that a simple powder XRD ratio of the albite to illite peaks would suffice to distinguish the preg-robbing ore for grade-control purposes.

Jan 1, 1999

The sulphide ore occurring in the North Mine at Broken Hill is of a complex nature, consisting of an intimate mixture of argentiferous galena, marmatite (zinc-iron sulphide), and gangue minerals. A typical analysis of the ore is:Lead 15.2%Zinc 12.0%Iron 5.3%Manganese 0.8%Copper 0.1%Alumina 0.3%Lime 0.9%Sulphur 11.1%Insoluble 53.8%Carbon dioxide 0.3%Undetermined 0.2%Silver 9 oz. per tonTotal 100.0%The metallurgical practice for the recovery of the lead concentrate and zinc concentrate from the crude ore is briefly described in the following pages.(1) COARSE CRUSHING AND FINE GRINDING OF THE CRUDE OREThe crude ore from the mine, containing lumps to the size of, roughly, 10 in. x 8 in., is tipped over grizzlies with the bars spaced 3 in. apart; the oversize gravitating to a...

Jan 1, 1933

By A D. Pradana, D R. Pradana, Y H. Putra, Z Zulhan, T Hidayat

The high temperature processing of nickel laterite ore is currently dominated by the Rotary Kiln- Electric Furnace (RKEF) technology. The ratio of SiO2/MgO (S/M) in the ore is one of the critical parameters that determines the success of the RKEF process. Incompatible S/M ratios in the ore can cause aggressive chemical interaction between the slag and MgO refractory. The slag-refractory interaction at conditions relevant to nickel laterite ore smelting was investigated in the present study. Synthetic mixtures representing the slag compositions of nickel laterite ore smelting were prepared by mixing MgO, SiO2, Al2O3, CaO, Fe2O3, and Fe and heating the mixtures in steel containers at 1300°C under an argon atmosphere for 3 hrs. Pure MgO crucible were used as containment material in the melting process of the mixtures to represent the MgO refractory. The kinetics of the slagrefractory reaction were investigated using samples with selected initial S/M ratios of 2.0 and 3.0 (wt/wt) (with constant CaO = 3 wt per cent, Al2O3 = 5 wt per cent, FeO = 10 wt per cent) by performing melting at 1500°C in MgO crucibles for 5, 30, and 120 mins under an argon atmosphere. The effect of the S/M ratio in slag on the slag-refractory interaction was also investigated by performing melting of mixtures with different initial S/M ratios of 1.75, 2.0, 2.5, and 3.0 (wt/wt) in MgO crucibles at 1500°C for 120 mins under an argon atmosphere. After the melting process, each sample was quenched in water, mounted in resin, ground, polished, and coated. The interaction between the slags and MgO refractory was then evaluated by analysing the polished samples using a scanning electron microscope equipped with an energy dispersive spectroscopy (SEM-EDS). Thermodynamic simulations using FactSage™ 8.0 thermochemical software were performed based on the experimental slag compositions, refractory, and conditions to support the evaluation process. The results show that a higher S/M ratio in slag leads to a higher tendency for the refractory component to dissolve into the slag. A higher S/M ratio in slag also leads to an increasing extent of solid-state diffusion of iron oxide into the remaining refractory grains. The dissolution of MgO into the slag is rapid; the MgO concentration in the final slag increased by 2.4 wt per cent and 5.7 wt per cent at initial S/M ratios of 2.0 and 3.0 wt/wt, respectively, within 5 and 30 mins of the melting process.

Aug 21, 2024

By I M. Platten, C J. S Sangster, Y Xie, S C. Dominy

Cononish is a steep, narrow NE-SW trending vein system that was emplaced into late Proterozoic metasediments. It shows brittle style deformation and postdates metamorphism and associated Caledonian foliations. The ore shoots plunge 45¦SW, have a 40 to 80?m intersection with the existing underground development and extend between 40 and 260?m down plunge. Small-scale sulfide-bearing domains within the vein carry the highest gold grades. They collectively define the ore shoots, where one or two and rarely three of the domains are present at an individual site in the vein. Gold occurs as electrum, with minor native gold. Silver occurs additionally as tellurides and native metal. The gold/electrum is fine-grained, generally <100?¦m in size and locally clusters. Visible gold up to 2000?¦m in size is rare. Gold and silver are generally spatially associated with sulfides in quartz. The main sulfide is pyrite, but galena, chalcopyrite and sphalerite occur also. Electrum and gold occur with galena in pyrite-hosted fractures. Gold is also associated with the contacts between galena and pyrite grains. Discontinuity of individual domains, variation in domain thickness and internal heterogeneity results in short scale variation in grade across the structure. Over 16?km of diamond drilling and a 1.2?km exploration adit has provided data to support a Mineral Resource estimate of 169?000?oz Au and 631?000?oz Ag reported in accordance with the 2004 JORC Code.CITATION:Dominy, S C, Platten, I M, Xie, Y and Sangster, C J S, 2013. Gold-silver vein mineralisation at Cononish, Scotland, in Proceedings World Gold 2013 , pp 445-454 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By P Breuer, X Dai, A Bergamin, D Hewitt

"Copper-ammonia-thiosulfate?leaching of gold has been researched for several decades as a potential alternative to cyanidation. However, this technology has not yet been applied commercially due to many challenges such as complex solution chemistry, reagent degradation and losses, system instability with losses of precious metals and difficulties in gold recovery from the leachate. Progress has been made at CSIRO in tackling some of these challenges including:better understanding and control of the leach conditions to minimise reagent losses whilst maximising gold recovery use of strong base ion exchange resins to recover the gold strategies to deal with polythionates that adsorb competitively with gold on ion exchange resins development and evaluation of process flow sheets.As a result there has been increased interest from the gold industry and renewed activities to develop thiosulfate based processes for gold recovery. One application area, which has been developed to the point of piloting, is the treatment of gravity gold concentrates using a copper-ammonia-thiosulfate leach with ion exchange recovery of the gold thiosulfate. This paper describes some of the advancements in the development of a potential process flow sheet for this application.CITATION:Dai, X, Breuer, P, Hewitt, D and Bergamin, A, 2013. Thiosulfate process for treating gold concentrates, in Proceedings World Gold 2013, pp 61-70 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 26, 2013

By S T. L Harrison, J-P Franzidis, M Becker, N Dyantyi, J L. Broadhurst

Gold mining is a major contributor to the South African economy, but is associated with several environmental issues such as acid rock drainage (ARD). ARD is due to the oxidation of sulfides in gold tailings and is characterised by low pH, high sulfate content and elevated concentrations of heavy metals that contaminates scarce water resources and subsequently limits the use of such waters without treatment. Treatment strategies can only be implemented if the acid-generating potential of mine wastes is effectively predicted using common static and kinetic acid prediction tests. The choice of test performed is usually a trade-off between the number of samples, speed of the test, cost of the analysis and level of information obtained. Often the results of these various tests are not consistent with one another. This study uses mineralogy to analyse biokinetic test results of a Witwatersrand gold sample in order to improve the understanding of behaviour of mine wastes under different ARD prediction test conditions.All ARD prediction testing methods investigated in this study showed that the gold sample is considered to be potentially acid forming with net acid generation (NAG) pH of 2.5 and net acid producing potential (NAPP) of 36 kg H2SO4/t. Results of biokinetic test showed that ANC was consumed within four days confirming acid producing potential of the sample with low neutralising potential as observed from acid base accounting (ABA) (4.7 kg H2SO4/t) and mineralogy (4.9 kg H2SO4/t). Results generated in this study demonstrated importance of mineralogy in both understanding the controlling reaction mechanisms playing key role in ARD formation and its capability as a prediction technique. Future work will focus on the application of mineralogy in interpreting the behaviour of mine waste under different static test conditions with a view to assessing their applicability and reliability in estimating potential acid generating characteristics of gold tailings.CITATION:Dyantyi, N, Becker, M, Broadhurst, J L, Harrison, S T L and Franzidis, J-P, 2013. Use of mineralogy to interpret laboratory-scale acid rock drainage prediction tests - a gold case study, in Proceedings World Gold 2013, pp 519-526 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By R Whittering, C Greet

High chrome grinding media has been used in the mining industry for quite some time, as it often proves economical on a wear basis. However, it is unusual for an operation to change to high chrome solely due to its metallurgical benefits. KagaraÆs Mount Garnet operation made the change from forged steel to high chrome media after laboratory testwork indicated that copper grades and recoveries would improve. The outcome was remarkable with positive changes in pulp chemistry throughout the circuit accompanied by marked improvements in copper, lead and zinc grades and recoveries. Reagent dosage rates were reduced, often by more than half, and the grinding media wear rate dropped to less than a third of the wear rate of the forged steel media. The economic analysis showed that out of the total increase of revenue and savings from metallurgical improvements and reagent and media consumption reductions the metallurgical improvements made up approximately 73 per cent, the reduced reagents saved 25 per cent and the savings through reduced media wear contributing by just over one per cent. This indicates that the popular view of high chrome media only being trialled in the plant for wear economics is outdated and the focus of operations should be shifted to using high chrome media for the metallurgical benefits.

Jan 1, 2006

By G T. Jemwa, F Rousseau, F J. Wolfaardt, J A. M Rademan, P W. Smit

Mining companies are increasingly faced with the challenge of reducing operating costs while maximising throughput and profitability. At the same time, the grade and quality of treated ores are becoming poorer and more variable, resulting in suboptimal process performance.It is now widely accepted that strategies to drive operational goals must revolve around improving plant availability, reliability and process efficiency. In particular, progress in plant automation and control systems has seen a trend towards unified frameworks for control and optimisation of mineral processing plants. These frameworks seek to seamlessly integrate different roles and tasks involved in process operations - IT, automation, plant maintenance and operations. An integrated solution framework for reducing process variability, increasing process efficiencies and maximising plant availability and reliability is discussed within the context of a typical milling circuit. The framework exploits a real-time analysis ægapÆ evident in production operations that prevents timeous identification of equipment and process failures. This is achieved by leveraging predictive analytics for equipment health monitoring, control loop monitoring and advanced regulatory control solutions towards enhanced process performance, improved asset management and regulatory compliance. The framework provides for early and actionable warnings on equipment and process degradation using real-time operational data.Resolving these problems can potentially avoid unplanned downtimes, process instabilities and other operational surprises, thus ensuring optimal plant throughput and optimal process behaviour for improved recoveries. Integrating control systems and plant automation with advanced analytics to analyse and optimise processes enables operations to achieve reductions in the variability of key process parameters. In addition, early detection of equipment malfunction or suboptimal process conditions leads to improved equipment availability and reliability. Ultimately, these operational gains reflect in profitability because of plant throughput and recovery gains. These benefits are demonstrated using data from a South African gold mining operation, where such an integrated asset and process health monitoring framework for process optimisation has been implemented.CITATION:Jemwa, G T, Wolfaardt, F J, Smit, P W, Rademan, J A M and Rousseau, F, 2013. Towards an integrated framework for asset and process health monitoring and optimisation on a milling circuit, in Proceedings World Gold 2013, pp 137-148 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By G E. Smith, G N. Lye

Wall control blasting practices are necessary to reduce the impact of blasting on mine faces but can also have a significant negative impact on mine productivity and operating costs. The conventional practice in deep open pit mines is to use so-called trim blasts adjacent to pit walls. To provide burden relief these trim blasts have fewer rows than full production blasts and are fired to a cleared free-face; hence they are termed æunchokedÆ. This practice leads to scheduling constraints on the pit operations and can cause ore dilution due to excessive muckpile movement. The use of such trim blasts stems from the perception that increased wall damage results from æchokedÆ blasts. These concerns are based on the unproven assumptions that blast vibration levels and explosive gas penetration increase with increased blast burden and face confinement. This paper describes work undertaken as part of a major investigation into wall control blasting at the KCGM Fimiston Mine, Kalgoorlie, Western Australia. It details a study to assess damage effects due to blast burden. Borehole air pressure measurements and borehole video camera inspections were done behind a series of single blastholes drilled with varying burden distances, as well as behind a dedicated trim blast and a full production blast. It was found that the measured damage effects, including visible rock cracking, dilation, and the limited extent of gas penetration behind the blastholes, did not vary significantly with burden or blast type for the cases tested. This result was in complete agreement with detailed vibration measurements conducted by Blair and Armstrong (2001) during the study, which found that vibration was independent of blast burden. As a result of these investigations, changes to the blasting practices at the mine were implemented. Dedicated trim blasts and free-face blasting have been replaced by modified production blasts and the practice of æchokingÆ blasts has been introduced. This has resulted in a significant improvement in productivity and cost savings without compromising pit wall integrity.

Jan 1, 2001

By K Afewu, R Dunne, W P. Staunton

The treatment of preg-robbing gold ores has always been a technical challenge in the gold industry. Early solutions included removal of preg-robbing carbonaceous material by flotation, the addition of kerosene to æblindÆ/passivate the surface of the preg-robbing component, and the most effective of all options, roasting the ore. Unfortunately gold ores have become more complex and roasting has environmental challenges, so other methods of treatment have had to be found. This paper will review methods of characterising preg-robbing gold ores, method of treatment and cite examples of actual application in the industry.CITATION:Dunne, R, Staunton, W P and Afewu, K, 2013. A historical review of the treatment of preg-robbing gold ores - what has worked and changed, in Proceedings World Gold 2013 , pp 99-110 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By P de Caritat, A Davidson, A Mann

Top outlet sediments from the National Geochemical Survey of Australia have been extracted by a partial extraction method for over 50 elements including gold. The partial extraction results from this low-density survey show discrete coherent anomalies for Au in the vicinity of many of AustraliaÆs known goldfields, and in the vicinity of some minor gold occurrences. In several instances catchment outlet anomalies for Au have been recorded from areas not known to contain significant economic gold. Several large economic goldfields are shown to not produce anomalies in catchment outlet samples. A survey of overbank samples in the Swan Avon catchment of Western Australia at double the sampling density shows that low level anomalies (>1 ppb) can be traced back to source using overbank sediments. Follow-up of one of the Au anomalies at Kent River in previously regarded non-auriferous terrain (western Albany-Fraser Belt) indicates a non-economic, but perhaps geochemically significant, Au anomaly with associated pathfinders including palladium. This may indicate that further exploration of the western part of Albany Fraser Belt for Au is warranted. The combination of catchment overbank samples and partial analysis technique has been shown to be effective at locating the source of gold anomalies from initial low-density continental and regional surveys.CITATION:Mann, A, Davidson, A and de Caritat, P, 2013. High resolution soil geochemistry for gold exploration at the continental, regional and prospect scale, in Proceedings World Gold 2013 , pp 167-174 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By A P. Wibowo

Indonesia holds a significant role in the utilisation of coal resources in the world. Although the number of Indonesian coal resources and reserves do not fall into the world’s top ten, according to 2009 statistics, Indonesia is the seventh largest producer of coal with a production of 256 Mt. More than 80 per cent of this amount is sold in the export market, making Indonesia the world’s second largest coal exporter. Most of the exported coal from Indonesia is used to fulfil the needs of the Pacific market, such as Japan, Taiwan, China, among others. It is also possible to reach the Atlantic market.Along with Indonesia’s development program, until 2025 the Indonesian government has adopted a National Energy Policy that aims to reduce the role of petroleum in electricity generation and replacing it with coal. As a follow-up of the policy, since 2009 PT PLN, the state electricity company has built steam power plants throughout Indonesia as an implementation of the first stage of the Electrical Acceleration Project with a capacity of 10 000 MW. Moving forward, in 2011 PT PLN will also build the second stage of the project with a capacity of 10 000 MW. As a result of the program, the domestic need for coal is expected to increase as much as 44.8 Mt.With the increase in domestic need and decrease in the number of reserves, the Indonesian government has adopted policies to secure the domestic coal supply. A policy that may potentially be adopted by the government is the limiting of coal production, seeing the high rate of increase in Indonesian coal production. The adoption of such a policy will change the distribution map of coal in the Pacific market. Thus, this paper will evaluate the change of coal distribution patterns in the Pacific market along with the increase in Indonesian domestic needs and Indonesian adoption of policies regarding the securing of coal supplies.

Nov 22, 2011

By Fickera M. A, Marshall S, Burgeese F. L, Burgees J, Estrina H

A new high intensity flotation process FASTFLOT was deployed to recover residual zinc from the zinc circuit tailings at Pasminco Mining's Concentrator, Broken Hill. Performance of the FASTFLOT process is discussed with respect to various size fractions. Results suggest that the process has an affinity not only for fine particles but also for +200 ¦m particles which the conventional flotation cells failed to recover. Various strategies for FASTFLOT deployment are also discussed.

Jan 1, 1995

By W T. C Kendall, H D. Ngo

Garden Well is a shear-hosted Archaean orogenic gold deposit located 100 km north of Laverton, Western Australia. The Garden Well processing plant is designed for a nominal 491 t/h milling rate and annual capacity of 4 Mt. The plant has three key innovations:1. a scrubbing circuit, expected to reduce grinding power consumption by up to 20 per cent2. a secondary cycloning/gravity circuit, providing a second opportunity for gravity gold recovery (additionally, the circuit effectively increases the leach residence time of the coarse gold bearing fraction of the leach feed by approximately 60 per cent, without any additional tankage)3. the use of mid-stream oxygenation to enhance gold recovery.The Garden Well deposit is free-milling with overall laboratory gravity/leach gold recoveries exceeding 95 per cent at a P80 grind size of 150 ¦m. Three mineralogical domains have been identified: oxide, transition and fresh, with the fresh domain having subdomains of fresh ultramafic and fresh shale. There is a high component of gravity recoverable gold in all three domains.This paper will discuss these innovations and the design challenges and the risk mitigation strategies that were adopted to ameliorate the prototyping risk. The performance of the plant since commissioning together with lessons for the future will also be presented.CITATION:Smith, R J, Kendall, W T C and Ngo, H D, 2013. Treatment plant innovation at Garden Well, in Proceedings World Gold 2013 , pp 315-324 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By T Bookless, J Pownell, D Meadows

The ever increasing trend of the gold price has meant that ore deposits that were previously considered too complex, or unattractive by virtue of their low gold grade, are now being investigated more closely. These ore deposits present a greater risk of failure than previously was the case. To ensure that the risk of project failure is reduced and the maximum value is derived from the deposit, its mineralogy, as well as other characteristics, should be well understood such that the optimum process can be designed.Quite often the flow sheet design is assembled using individual process components, from various sources, and without consideration of the complete system. Test work programs require careful planning and an open viewpoint in terms of comminution circuit design particularly with respect to ever increasing power costs across the globe. As an example, high pressure grinding roll (HPGR) technology in many cases offers better mineral liberation than the more traditional comminution devices and it does so at a reduced energy input, and yet HPGR test work is often restricted in its scope due to the perceived novelty of the technology and the resultant lack of generally agreed and accepted test work routes.In this paper the authors outline a typical HPGR test work process route driven by the needs of different ore types and illustrate that to optimise the project value, any test work program should start from the premise that thorough understanding of the ore is vital.CITATION:Bookless, T, Meadows, D and Pownell, J, 2013. Enhancing project value through a designed high pressure grinding roll test work program, in Proceedings World Gold 2013 , pp 291-300 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By M Orunesu Preiata

The Odysseus Project is part of the high-grade Cosmos Nickel Complex that lies 30 km north of Leinster. The Odysseus definitive feasibility study (DFS) was approved by the Western Areas’ board in October 2018. Early works commenced in January 2019 with rehabilitation of the existing underground infrastructure. In June 2022 Western Areas was acquired by IGO Ltd. The project is now well advanced to meet its target of first concentrate. The project included the construction of a haulage shaft. The design of the hoisting equipment and the shaft barrel evolved from the initial DFS design stage to the final execution, as the data were made available from the initial investigation to the data gathered during execution (although this did not change from its initial concept). The design philosophy for the haulage shaft incorporated, from the beginning a multidisciplinary approach with inputs from three main areas involved in such projects, namely excavation techniques, geotechnical assessments, and infrastructure construction. This interaction is a fundamental component for the success of such a critical project. In fact, each of these three areas influences each other in a cyclical manner, triggering a continuous review of the project inputs and outputs, while maintaining the original project goals: the design of an infrastructure able to deliver the desired throughput. The throughput dictates the infrastructure that needs to be built, which in turn controls the size of the shaft. The key assumption applied to this is that the rock mass can accommodate the excavation void, and the excavation technique with its tolerances and limits that ultimately need to be verified back with the initial assumptions used for the infrastructure design. The aim of the paper is to present a case study of the experience gained with the Odysseus hoisting shaft and to propose a possible logic path for similar projects elsewhere.

Mar 29, 2023

By M P. Sandy, J B. Albrecht

"Narrow vein mining can be loosely defined as mining operations involving orebodies with a true thickness of less than 4 m. Some authors have limited the term to steeper-dipping orebodies where the ore will rill under gravity. However, ænarrow veinÆ can also legitimately refer to some of the flatter orebodies, such as many of the platinum, chrome and gold deposits of Southern Africa, and several in Australasia including Bullen (at Norseman), Sunrise Dam, Telfer (Patterson, 1993) and the famous æflatmakesÆ at the Emperor Gold Mine in Fiji (Gordon and Harmse, 1993). Where the orebody dip is less than about 40¦ additional effort is usually required to remove the broken ore, including the use of scrapers, hydraulic monitors or remote-operated excavators (Tombs, Buckingham and Hancock, 2008).Working in such narrow orebodies presents particular operational and geomechanics challenges. A range of mining methods have been developed or adapted to exploit narrow orebodies including:cut-and-fill,narrow vein bench or longhole stoping,Alimak stoping,shrinkage stoping, and methods for shallow dipping orebodies (including Airleg and mechanised methods).The paper discusses some of the advantages and disadvantages of each method with a focus on geotechnical aspects including mining sequence options, stress management, ground support requirements, dilution and recovery.CITATION:Sandy, M P and Albrecht, J B, 2012. An overview of geotechnical issues in narrow vein mining, in Proceedings Narrow Vein Mining 2012 , pp 185-194 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 26, 2012

By J Tiihonen, J OÆCallaghan, T Haakana

Outotec is today capable of providing technologies, process equipment and engineering for the construction of pressure oxidation leaching (POX) plants in any location in the world. Outotec works with customers from mine to pure metal, participating in plant design from the process development phase (including test work execution/supervision) to plant commissioning and operations. Either key equipment technology packages with basic engineering or entire POX plants can be supplied.The addition of pressure oxidation equipment to OutotecÆs product portfolio adds to and complements already existing significant experience in general hydrometallurgical process and proprietary equipment design and supply.In addition to providing key pressure vessels, piping and valves to a POX plant, Outotec can offer an enhanced and proven autoclave agitation system that maximises oxygen mass transfer and utilisation. Novel energy and water recovery technology can also be tailored to a customerÆs specific needs. Importantly Outotec owns and operates extensive test work facilities and can provide test work to ensure the optimum POX flow sheet and materials of construction. Outotec ensures that best available technology (BAT) concepts are used in POX design to improve the availability of the process and minimise unpredicted shutdowns.CITATION:Tiihonen, J, Haakana, T and OÆCallaghan, J, 2013. Outotec pressure oxidation - more out of sulfide ore, in Proceedings World Gold 2013 , pp 197-206 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By A Woodley, G Keir

The mining industry faces concurrent pressures of reducing water use, energy consumption and greenhouse gas (GHG) emissions in coming years. However, the interactions between water and energy use, as well as GHG emissions have largely been neglected in modelling studies to date. In addition, investigations tend to focus on the unit operation scale, with little consideration of whole-of-site or regional scale effects.This paper presents an application of a hierarchical systems model (HSM) developed to represent water, energy and GHG emissions fluxes at scales ranging from the unit operation, to the site level, to the regional level. The model allows for the linkages between water use, energy use and GHG emissions to be examined in a flexible and intuitive way, so that mine sites can predict energy and emissions impacts of water use reduction schemes and vice versa. This paper examines whether this approach can also be applied to the regional scale with multiple mine sites.The model is used to conduct a case study of several coal mines in the Bowen Basin, Australia, to compare the utility of centralised and decentralised mine water treatment schemes. The case study takes into account geographical factors (such as water pumping distances and elevations), economic factors (such as capital and operating cost curves for desalination treatment plants) and regional factors (such as regionally varying climates and associated variance in mine water volumes and quality).The case study results indicate that treatment of saline mine water incurs a trade-off between water and energy use in all cases. However, significant cost differences between centralised and decentralised schemes can be observed in a simple economic analysis. Further research will examine the possibility for deriving model up-scaling algorithms to reduce computational requirements.CITATION:Keir, G and Woodley, A, 2013. Regional trade-offs between mine water and energy use - a water treatment case study, in Proceedings Water in Mining 2013 , pp 21-28 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

By K White, R Hardie, J Merritt, B Kirsch, R Lucas

Constructed stream diversions are a common element of mine sites across Australia. A review of constructed stream diversion performance in the Bowen Basin funded by the Australian Coal Association Research Program (ACARP) in 1999 found over 80 per cent of constructed stream diversions failed to meet regulator and operator expectations. Since that time, improvements have been made in the assessment, design, monitoring and management of constructed stream diversions. Fundamental to these improvements has been the development of a better understanding of the regional stream systems and efforts to replicate the natural stream processes in the function and operation of constructed stream diversions.This paper discusses the history of constructed stream diversions through the Bowen Basin in central Queensland recorded in the outcomes of a series of ACARP funded research projects. Further, the paper reports on the outcomes of a current ACARP funded project that has reviewed the success or otherwise of constructed stream diversions in the region. The assessment has compared the performance of diversions that have been designed to replicate and provide for ongoing stream geomorphic processes with those diversions that were designed and built prior to the development of these design improvements. Based on these investigations we have identified design and construction successes and issues requiring further research and management attention.CITATION:White, K, Lucas, R, Hardie, R, Merritt, J and Kirsch, B, 2013. Challenges and opportunities for constructed stream diversions in the Bowen Basin, Central Queensland, in Proceedings Water in Mining 2013 , pp 73-82 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013