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By C P. C David, J P. T Domingo

Addressing nutrient deficiency, among other factors, is vital to the growth and establishment of plants in mine spoils and tailings ponds. Although several organic amendments are available for this purpose, it is important to determine the appropriate ameliorant for the selected plant species. This research examined the effect of different amendments on the growth and ground cover of Centrosema molle, Calopogonium mucunoides and Sorghum spp. in copper/gold tailings. Plant growth and ground cover drastically increased with the application of organic ameliorants, especially manure. Among the three plants, Calopogonium exhibited the best growth and has shown its capability to establish a dense ground cover even in unamended tailings. Results suggest that the plant species and the ameliorants used in this study could be effective in a low-input approach to mine rehabilitation.CITATION:Domingo, J P T and David, C P C, 2014. Legume and grass revegetation of mine tailings, in Proceedings Life-of-Mine 2014 , pp 525–534 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By M Barkh, F X. Spachtholz

The mining industry faces significant environmental challenges in managing tailing ponds and wastewater treatment, including the risk of contaminated water, breaches of tailing dams, and energy-intensive treatment processes. Traditional methods involve pumping water to secondary treatment facilities for neutralisation, which is costly and poses operational and environmental risks. In response to these challenges, the Professional Mine Water Action Plan (PMAP) introduces a revolutionary approach that combines cutting-edge AI technology and environmentally friendly reagents for in situ neutralisation of acidic wastewater. PMAP leverages magnesium-based slowrelease reagents and AI-driven intelligent dispensing systems to optimise treatment processes within the tailing pond itself. The unmanned smart dispensing vessel (USDV) conducts bathymetry to gather data on water quality and hydrography, allowing the system to determine the appropriate reagent quantity and injection strategy. This approach transforms the tailing pond into virtual reaction columns, enabling individual and simultaneous water treatment while optimising efficiency. PMAP’s novel reagent demonstrates exceptional efficacy in removing critical metals like cobalt, nickel, and copper, as well as reducing harmful metals such as mercury and manganese to undetectable concentrations. Unlike traditional lime-based treatments, PMAP’s reagent prevents gypsum formation and reduces waste volume significantly, improving reagent utilisation and solid waste handling. Furthermore, PMAP technology offers benefits beyond environmental stewardship. By reducing water treatment costs and improving resource management, it enhances operational efficiency and aligns with broader corporate sustainability goals. Additionally, PMAP expedites permitting processes by eliminating the need for traditional water treatment infrastructure and mitigating risks associated with hazardous reagent transportation. Integrating PMAP as a pre-treatment for existing lime facilities provides further benefits, including optimisation of treatment operations, reduced reagent consumption, and the recovery of valuable metals from generated sludges. Overall, PMAP represents a groundbreaking advancement in mining wastewater management, showcasing the transformative potential of AI and environmentally friendly solutions to foster sustainable and responsible mining practices globally. Its inaugural project in the Yukon Territory aims to demonstrate its capability to remove contaminants from mine water, paving the way for widespread adoption in the industry.

Sep 1, 2024

By A B. Jahed, Ö Aydan, T Ito

In this study, the authors compiled some case history data and present some typical examples of rock slope stability issues in Afghanistan with a special emphasis on Kandahar region and categorise rock slope failures according to the principles of modern rock slope engineering. The slopes considered involve rock-cut, natural rock slopes mainly. The effect of structural geology and discontinuous nature of rock mass on both slope-cuts and natural rock slopes is taken into account and some preliminary assessments on the stable and unstable rock slopes are presented. Furthermore, the seismic effect on their stability is also considered. It is also pointed out that similar issues could be observed in open pit mines, which may be exploited in years to come.

Nov 29, 2022

By M Jacobs

This abstract discusses a heap leach copper mine that was failing to perform and as a result was not meeting targeted production. The mine had numerous technical challenges including: high water inflows, low levels of geotechnical monitoring, performance issues with mining, resource model and grade control reconciliation issues, and unexplained low levels of performance from the heap leaching operations. A team from various organisations with specialist skill sets including: a forensic accountant, the owner’s representative and a mining engineer, was arranged to visit the site. The task was to investigate the situation and determine what could be done to turn the performance of the mine around. After an initial assessment in late 2018, efforts were directed to better understanding the operations and improving the performance of the site through preventative management. A key part included the creation of production forecasts that could be achieved that would help restore confidence in the operations. Uncertainty in the mine achieving production forecasts and the performance of the heap leaching operations were contributing to the decline of the operations. Investigations uncovered the fact that while the resource model could reliably predict total copper, a lack of sequential leach data meant the accurate prediction of soluble and insoluble copper species, both important for heap leaching, was difficult to do with any degree of certainty. The crushing and mining contractors also appeared to have suffered somewhat from a lack of management by the owner’s team and performance had affected the production of copper. Collaboration and management were used by the team to understand and stabilise the operations. Ongoing collaborative efforts by the management team, site personnel and contractors resulted in a positive outcome for the owners and their mine – and could at yours.

Jun 22, 2022

By Rowe P, Rogers D, Warren M

Pressure cyanidation of the minus 10 micron slimes fraction of the Fimiston flotation concentrates for the recovery of gold values has been evaluated as an alternative processing route to the roasting and atmospheric cyanide leaching of the calcine. Laboratory and pilot trials have demonstrated that gold extractions of greater than 94 per cent can be achieved at cyanide consumptions of 12-24 kg/t and oxygen consumptions of 0.1-0.3 Nm3/t with total pressures of 1000-2000 kPa. Economic and operational assessment of several reactor configurations suggests autoclaves may be preferred over pipe reactors at treatment rates of 10 t concentrate/h.

Jan 1, 1996

By L Sandery, S Light

Within 22 months of commencing decline development, the Prominent Hill Ankata Underground Project achieved its full production rate of 1.2 Mt/a.In 2010 construction of the Ankata Underground Project was approved. Decline development commenced in November 2010 and the turnout for the first sublevel was reached by August 2011. The first stoping ore was produced in the first quarter of 2012 and production was successfully ramped up to full production during the third quarter of 2012.Diamond drilling commenced in October 2011 and was conducted concurrently with the underground development. This presented challenges as mining and production targets had to be balanced with underground exploration activities. To achieve production on schedule, without adversely affecting the diamond drilling program and future development, meticulous and adaptive planning techniques were required. This included involvement from engineers, geologists, underground operators and underground diamond drillers.The granularity of these planning techniques allowed the management and prioritisation of development and diamond drilling down to an almost hourly basis. A constant flow of information from drill assay results was fed back into the planning systems. This resulted in a constantly evolving mine plan as the orebody was further refined. High priority areas were identified and targeted to allow continued development and a successful rapid ramp up to full production.CITATION:Sandery, L and Light, S, 2014. Managing the diamond drilling interactions in commissioning the Ankata underground mine, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 75–80 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

A thick sequence of alkaline intrusions and volcanic rocks underlies a Quaternary caldera on Liliir Island. The sequence is host to a still active sub-aerial hydrothermal system and associated epithermal gold mineralisation. Sub-horizontal alteration horizons exhibit progressively increasing chondrite norma-lised (La/Lu) en and (La/Sm) cn ratios from unaltered shoshonites, to the potassic alteration zone, to the argillic altera-tion zone to the advanced argillic alte-ration zone. The increasing fractionation of HEE, and especially of LHEE, up the alteration sequence is the result of de-creasing pH, temperature and alkalinity of the hydrothermal fluids with increa-sing alteration intensity. HRE3 were especially mobile in argillic and advanced argillic alteration units characterised by acid fluid conditions and large fluid volumes. Abundant Cl, S and CO2 within the hydrothermal fluids and thus abundant REE complexing agents and large fluid volumes favoured the mobility of REE during hydro-thermal alteration of the volcanic rocks and intrusions. Steam escape, mixing of the gases with groundwater and a change from a magmatic neutral chloride hydro-thermal system to a meteoric acid sulphate system was accompanied by liquid/vapour ratio changes, pronounced alkalinity, pH and temperature decreases, and fluid/rock ratio increases. This caused the mobili-sation, fractionation and deposition of PF.F.

Jan 1, 1990

By A Muhairini, M Eggers, J Smith, H Baxter

Detailed geochemical analysis of cored and non-cored drill hole data was used to characterise and model the Cenozoic detrital valleys of several deposits within the southern Pilbara region, Western Australia. The purpose of this modelling was to better characterise and understand the relationships between the various geotechnical units comprising mixtures of rock and soil for the purposes of slope stability and depressurisation studies.This paper presents data from several valleys where geological, geomorphological and climatic processes have resulted in the deposition of heterogeneous detrital rock and soil sequences. Seven primary detrital units are recognised as occurring within all the valleys studied, suggesting that the geological processes involved in the erosion and deposition of the units were widespread. Geochemical assessment of cored and non-cored data suggests correlatable geochemical signatures can be recognised for each of the units; however, local variability in the groundwater history of individual valleys is demonstrated by late-stage carbonate precipitation recognised both in the core and through the geochemical signatures, which has resulted in alteration of the parent rock/soil material. This paper discusses how the carbonate alteration may lead to improvements in rock/soil mass strength of a clay unit by comparing laboratory strength test samples of the same parent material with varying degrees of precipitate alteration to those with no discernible carbonate alteration. Following from this, correlations with geochemical assay results have been derived, whereby zones of more favourable strength conditions may be modelled through assessing areas of analogous geochemistry.The paper demonstrates how geochemical assessment can lead to improved geotechnical and hydrological modelling for a detrital valley system without the need for significant coring and laboratory testing. This in turn leads to improved confidence in the slope design and depressurisation recommendations for a slope.CITATION:Baxter, H, Eggers, M, Muhairini, A and Smith, J, 2015. The effect of carbonate alteration on detrital mass strength and implications for geotechnical slope design, in Proceedings Iron Ore 2015, pp 429–436 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By T J. Napier-Munn, T Perkins

The JK Drop Weight test was developed at the Julius Kruttschnitt Mineral Research Centre (JKMRC) in the early 1990s as a means of characterising ore for the purposes of AG/SAG mill and crusher modelling. It has since been used extensively worldwide in the minerals industry as a key ore characterisation test which produces parameters which are used in comminution circuit design and optimisation. The test generates three parameters which are used in the AG/SAG mill model of the JKSimMet software. The resistance of the ore to high energy (impact) breakage is quantified with the A and b parameters. The oreÆs resistance to low energy (abrasion) breakage is measured using the ta parameter. The accuracy and precision of the results of the JK drop weight test are of great importance given that the parameters are key inputs in the design of such capital intensive items as SAG mills. Plant optimisation exercises also rely on the accuracy of the parameters to assist with improving the performance of an existing circuit. A thorough analysis of the accuracy and precision of the parameters generated by the JK drop weight test has now been undertaken by JKTech Pty Ltd (JKTech). An experimental program was designed using statistical methods to plan a hierarchical set of 24 drop weight tests on homogeneous material. Each stage of the test was identified and incorporated into the experimental design so that the contribution to the overall error of each stage could be quantified, including the effect of operator. The data were analysed by nested analysis of variance. An overall analysis of the A, b and ta parameters generated from the test program has now quantified the variance of these parameters more thoroughly than ever before. Using the results for the impact parameters, an analysis has been carried out to investigate the effect of these variances on final SAG mill comminution circuit design. The results will also be used to refine the comparative testing procedures currently in use by licensees worldwide.

Jan 1, 2008

By T Ireland, B Wright, S Weaver

All tunnels have unique characteristics that result in different fire and life safety risk. The fire safety systems for each tunnel also give different benefits at different costs. It is therefore neither pragmatic nor cost-effective to prescribe specific fire standards requirements for all tunnels. Each tunnel needs to be assessed individually but using a common process.The owner/client is normally the risk owner and needs to make the decision on what fire and life safety provisions will be provided within the tunnel. To make this decision they need to be appropriately informed. The low probability and high consequence nature of fire events creates a challenge such that traditional analysis processes, which tend to focus on a major event after it has happened, are not easily applied and do not give the best value for money. Therefore a process is required that provides the relevant information to the owner for decision-making.A quantitative risk assessment (QRA) provides a process and framework for the consideration of fire life safety risk when applied properly. This involves a risk assessment of the ‘do nothing’ option together with assessments of improvement options and their costs. It also involves consideration of benchmark safety levels for other tunnels and the open road.This paper will outline a QRA process for assessing fire and life safety risk in tunnels and how this has been used for three existing tunnels, Homer Tunnel, Lyttelton Tunnel and Mt Victoria Tunnel. Key challenges include determining an acceptable safety level, defining realistic inputs, providing sufficient complexity to get meaningful results but not so complex that transparency is lost and interpretation to enable decision-making by non-technical personnel.CITATION:Weaver, S, Wright, B and Ireland, T, 2014. A transparent and pragmatic quantitative risk assessment process for assessing fire safety in New Zealand tunnels, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 121–128 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By B Wu, B W. Lei, B J. Duan

When a coalmine fire occurs, it is crucial to judge the developing trends inside the fire area by analysing the changes of gas concentration in order to formulate the proper rescue measures. At present, few researchers have focused on the relationship between the changing trend of gas product and basic characteristics of fire in the coal fire extinguishing process. To study the relationship of basic characteristics of coalmine fire during the extinguishing process, an experimental platform for coal combustion in a confined space was built, and gas production, flame image and coal temperature during the extinguishing process were monitored and analysed by an online continuous gas analysis instrument, camera and thermocouple. Research shows that during the burning phase of the coal sample in the confined space, the flame zone decreases gradually due to insufficient gas supply. The size of the flame zone fluctuates and shares a positive correlation with CO concentration, while sharing a negative correlation with O2 and CO2 concentrations. Then, in the extinguishing phase, the increasing rate of CO2 concentration and the decreasing rate of O2 concentration both decrease gradually, but CO concentration would rise for a period before it eventually decreases. Coal temperature continues to rise in the open flame stage and does not go down until the flame is extinguished.CITATION:Lei, B W, Wu, B and Duan, B J, 2015. Experimental study on extinguishing characteristics of coal fire in confined space, in Proceedings The Australian Mine Ventilation Conference, pp 279–284 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By A Dunne, R Kruger, H Coleman, P G. Laurens

External and internal challenges in mining are increasing the difficulty and complexity of operating mines. The external mining environment has a big impact on mining operations and is driving the focus on safety, sustainable mining, green issues, profitability and productivity. There is a very high emphasis on ‘reducing cost to improve’, lower mining and beneficiation costs by eliminating waste/inefficiencies (reduce people, use less consumables, multiskilling, etc). The internal mining environment is getting tougher to operate in, with the deposits being more difficult to mine, more difficult to manage due to external pressure along with issues associated with maintaining quality, etc.Technological and environmental developments too numerous to mention, mean that cost control models, reduction in human resource numbers, as well as other drastic measures to curtail expenditure and increase profitability have become part of everyday business. The capability to manage the mining environment in a systemic manner has been lacking and this increases the pressure for performance on those individuals operating and managing mines.Working smarter has become crucial to ensure that businesses optimise the use of their resources, become more safety conscious, more productive and remain cost-effective, while recognising the importance of sustainable mining now and in the future. The logic of determining and managing to the capability of the mining value chain will be examined and the underlying assumptions or beliefs guiding behaviour and decision-making will be highlighted.In order to identify the obstacles in the mining value chain that hinder achievement of its full potential, the following questions have to be asked:What are the factors that influence the performance of a mining value chain?What is the design capacity of the mine?How can the inherent flow and value capacity of a mine be determined?What types of solutions will allow a mine to operate at its inherent flow and value capacity?This article will discuss the way we plan, measure, assess and manage the mine value chain, by addressing the following factors:balanced capacity versus flow and value capacity designthe use of averagingoptimising individual components in a value chain versus optimising the whole value chain.Optimising flow and value through the mining value chain is one of the three pillars of Mineral Resource Throughput Management (MR™). MR™ is an entrenched and academically supported philosophy that has been successfully applied in the past decade in various mines throughout the world by EXXPLEO, a mining and beneficiation consulting company. EXXPLEO has partnered with HCL (a global IT company) to embed the MR™ philosophy, methodology and toolsets into a formal software product called Synchronised Digital Mining (SDM). The SDM system will provide mining companies with a sustainable platform to effectively apply the MR™ principles and toolsets effectively across all operations targeting increased productivity, efficiency and profitability without having to train operations and management staff into expert MR™ practitioners to successfully achieve the desired results.CITATION:Dunne, A, Laurens, P G, Kruger, R and Coleman, H, 2015. Optimising flow in the mining value chain, in Proceedings Iron Ore 2015, pp 437–442 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By X Dahe

SLon vertical ring and pulsating high gradient magnetic separators possess excellent mineral processing ability and have been widely applied to process oxidised iron ores. SLon centrifugal separators are applied to clean the SLon magnetic concentrate and remove quartz and other gangue minerals associated with a small portion of magnetite.This paper introduces the application of this technology in Hai Nan, Da Hong Shan and An Shan for processing oxidised iron ores.

Jul 11, 2011

By D J. Hill

"Mining companies routinely invest in improvements to their processing operations, but often these enhancements do not work to full effect.Improvements can be ineffectual because underlying process problems are not identified or prioritised for correction or repair.This is frequently because ‘black box’ solutions deployed to implement process control improvements typically rely on instrumentation to provide data for algorithms to work effectively, and these solutions are often ineffective or disabled at mineral processing sites.There are three key reasons they can fail to deliver: vital instrumentation is not calibrated or functioning as required basic process control and loop tuning was not implemented correctly or is in need of tuning there is an inability to support the ‘black box’ solutions on-site.Many of these problems can be overcome by implementing operational analytics that identify where problems are occurring and prioritise where improvements need to be made.Incorporating operational analytics into process improvement is not a new methodology. It is more a back-to-basics approach to make more efficient use of capital and systems already deployed.Data collection systems, such as the OSIsoft PI System, provide real-time and historical process information for process control experts to analyse and identify areas for improvement. However, most systems are not used effectively. With some simple enabling, data collection systems can provide evidence for prioritising investments in improvements and determining an investment’s effectiveness.MIPAC advocates that the initial step, with analytical evidence, is that clients review the control strategies and implement small influential instrument repairs/calibrations and operator training. This can significantly boost process productivity without the need to spend large sums of money on new capital or employing expensive, difficult to maintain ‘black box’ solutions.A simple Stage-Gate®-style approach ensures that small investments in evidence-based process improvements deliver significant benefits to mining operations.CITATION:Hill, D J, 2014. How to prioritise process improvements, in Proceedings 12th AusIMM Mill Operators’ Conference 2014, pp 307–314 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 1, 2014

By S L. Nicol, B J. Hogg, O J. Mendoza, S Nikolic, A Burrows

The top submerged lance (TSL) technology, developed in the 1970s, is now widely used for the processing of a range of materials. The key advantage the ISASMELT™ TSL technology provided was the ability to process feed materials in a highly turbulent bath, reaching close to equilibrium conditions, uniquely allowing for operation below the liquidus of the molten slag phase. The details on what happened below the liquidus line in the phase diagram became critical for the successful operation of the technology. During the development of the ISASMELT™ technology this led to a collaboration between the Process Technology group of Mount Isa Mines, now part of Glencore Technology, and the Pyrometallurgy Research Centre (PYROSEARCH) at The University of Queensland. The fusion of the phase equilibria research into the technology development allowed for understanding of the behaviour of molten splash, reliable tapping of the furnace, and the ability to operate the furnace with a refractory lining and achieve a year campaign life in excess of four years. The outcome has allowed for the highly successful adaption of the ISASMELT™ technology to recycling of complex feed streams necessary to drive circularity in our modern global economy.

Aug 21, 2024

By J King, T Hunter, R Coleman

"The industry that supports operations and new projects is suffering a rapid decline in the currently severely curtailed capital investment environment. This is evidenced by a decline in the number of skilled teams, who are now centred in fewer locations. Other features are an aging and retiring ‘Baby Boomer’ generation, coupled with a low uptake of new graduates and the uncertainty in predicting future capital expenditure programs and requirements. Combine this with a reluctance of cash-poor operations to modernise and adapt in an environment of low metal prices, and there is a real uncertainty in how service providers will meet industry needs as they evolve.The industry that supports operations and new projects is suffering a rapid decline in the currently severely curtailed capital investment environment. This is evidenced by a decline in the number of skilled teams, who are now centred in fewer locations. Other features are an aging and retiring ‘Baby Boomer’ generation, coupled with a low uptake of new graduates and the uncertainty in predicting future capital expenditure programs and requirements. Combine this with a reluctance of cash-poor operations to modernise and adapt in an environment of low metal prices, and there is a real uncertainty in how service providers will meet industry needs as they evolve.Trends amongst service providers will be put forward as well as developing options and alternatives. These embrace a whole gamut of agile alternatives in the areas of partnering, alliances, commercial and shared risk models and mutual innovations. These will be discussed with some case studies and suggested approaches.Particular emphasis will be upon brownfield expansions and upgrades which have emerged recently as a preferred lower capital and focused way to achieve best practical outcome at lowest cost. There are a number of specific features of such brownfields projects including the requirement for very close cooperation between the execution team, operators, maintenance and suppliers and a maximum usage of site resources and ingenuity. Often, required investment hurdle rates are high, downtime allowed is minimal and site resources usage is maximised. This requires mutual trust, good planning and high health, safety, environment and community (HSEC) standards and practice. In many ways the practices and skills needed are the exact opposite of the historical ‘big greenfields’ project with which the industry has been geared for more recently.Another developing area has been with innovative commercial models and practices. These have been as a direct result of the more challenging investment criteria being adopted and the relative hunger of service providers. It has become more common to look at these commercial/costing alternatives very early in the project cycle as an essential project tool and not just as a possible option. These commercial solutions cover such alternatives as leasing and rental, deferred payments, build–own–operate–transfer (BOOT) and build–own–operate (BOO), whole-of-mine preferred spares and maintenance terms, and aggressive performance targets with real assurance penalties. Once again this requires very close mutual dealings and trust, and sufficient time allocation compared to a conventional approach.Citation:Coleman, R, King, J and Hunter, T, 2016. Upgrades, Modernisations and Expansions... Where Will the Expertise, Capability and Skills Come from in the Future?, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 69–76 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By M Morey

Ok Tedi Mine is located eighteen kilometers from the Irian Jaya border in the Star Mountains, Western Province, Papua New Guinea. Sequential flotation concentrators produce a copper / gold concentrate for market, and a pyrite concentrate for environmental containment, with low sulphur tailings from the pyrite flotation sequence being discharged to river. Strict sulphur assay targets are set for the riverine discharge. Current porphyry and skarn ore blends from open pit operations at Mt. Fubilan will cease by 2017. However, drill cores indicate an economic ore body in the skarn ores surrounding and below the current pit limits. With proposed mining from a western pit wall ‘cut back’ and an eastern pit wall underground operation, potential for ore ageing in sub level cave underground stockpiles is apparent. With little information in the literature, Ore Ageing test work at prefeasibility level consisted of multiple one tonne stockpiles of -50 mm crushed rock. For the bankable feasibility study, a successful test work program was implemented utilizing 40 tonne ROM ore stockpiles composed of exposed pit extensions of future ores. Realistic ageing profiles of Skarn ores were obtained from one tonne monthly samples subjected to laboratory testing. Test work outcomes included:• Similar ore ageing profiles from both the pre feasibility study (PFS) and feasibility study (FS) programs, suggesting ore susceptibility to oxidation has greater effect in ore ageing than rock size for Ok Tedi skarns. • Laboratory rougher flotation of pyrite showed significant variation in sulphur recovery rate, suggesting three classes of pyrite floatability.• Laboratory rougher flotation of both copper and pyrite for up to 19 months ore ageing from 11 stockpiles, suggested three stages in the ore ageing process.

Aug 8, 2011

By P Sha

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Elaine Dorothy Cu-Au (REE-U) skarn deposit in the Mt Isa Inlier, Queensland, Australia is characterised by extensive metamorphic calc-silicate hornfels long before hydrothermal skarn and complicated deformation history. The deposit is hosted by the Corella Formation (1780–1740 Ma) and exhibits two phases of skarn formation in the study area – banded fine-grained diopsidic hornfels (Phase 1) and coarse-grain pyroxene skarn (Phase 2). Phase 1 skarn is predeformation and is interpreted to have been caused by the 1743–1734 Ma Burstall Magmatic Suites, whereas the coarse-grained pyroxene skarn (Phase 2 skarn) postdates the deformation and peak metamorphism events. Phase 2 skarn consists of prograde pyroxene, less garnet and titanite, retrograde epidote, REE-allanite, amphibole, biotite, and later sulfides, carbonate, quartz, anhydrite and chlorite. It hosts most of the copper mineralisation, with the REE elements occurring mostly in allanite. Titanite coexisting with allanite and Cu-Fe sulfides in Phase 2 skarn has been dated by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) at 1524 ± 9 Ma (207Pb/206Pb). The ages are similar to Williams-Naraku Batholiths, which outcrop approximately 40 km to the east in the Eastern Fold Belt. In Elaine Dorothy, the isotopic compositions for calcite cluster around 12.2‰ d18O and -3.7‰ d13C. It probably resulted from a mixing processes between marine sourced carbon-oxygen (ca 20‰ d18O and -0.5‰ d13C) and other distinct geochemical reservoirs, eg magmatic C-O. These features indicate that Phase 2 skarn and Cu-Au (REE-U) mineralisation may be related to unexposed intrusions at deeper levels.CITATION:Sha, P, Spandler, C and Chang, Z, 2015. Elaine Dorothy Cu-Au (REE-U) skarn deposit, in Proceedings PACRIM 2015 Congress, pp 445–450 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By S Cyphers, J Missen, B Jansen

The AGL Loy Yang Mine is one of the largest and most significant coalmines in Australia. Commencing in 1982, this mine produces 30–35 Mt/a to supply more than 50 per cent of Victoria’s electrical power requirements. At this mine there are unique geotechnical challenges to overcome to ensure its safe operation including: significant mine depth, low density of coal in the operating and permanent mine batters, the influence of groundwater and deep sediment aquifer pressures. One of the challenges is the behaviour of brown coal, which is neither a soil nor a rock and displays long-term creep stress relief. Other geotechnical challenges include ensuring stability in high unconsolidated dumps, potential large-scale block movement in mine batters driven by crack water pressure and heave from high-pressure aquifers.The paper will outline the geological and hydrogeological setting and potential failure mechanisms, and detail an integrated geographic information system and reporting regime that in part addresses ground control management at the mine. The paper will also outline the management processes for a dynamic geotechnical environment and the benefits of the alliance arrangements to meet the geotechnical requirements at the mine and the effective personnel integration in the mine technical services team.CITATION:Jansen, B, Missen, J and Cyphers, S, 2014. Geotechnical management at the AGL Loy Yang Mine, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 239–246 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By B Lumsden, R Smiles

Independence Group’s Jaguar Mine treats a polymetallic ore producing a copper concentrate and zinc concentrate. Effective separation of the sulfides requires relatively fine grinding with flotation feed P80 of about 75µm. Zn losses to final tails are greater than 60 per cent and <32 µm. When magnetic conditioning was first installed in 2010 it showed about an 8 per cent reduction of zinc in final tail and on some ores a similar benefit for silver as well. Current testwork is showing about a 12 per cent reduction in zinc and silver in final tail, consistent with the original testwork. Sizing of the final tail during the tests showed that the reduction of zinc and silver losses were only in the <32 µm fraction, as would be expected from an aggregation process. However, the most surprising result was about a 4 per cent reduction in zinc and silver in the plant feed with a >99 per cent statistical certainty. The reduction in zinc and silver in the feed is also only in the <32 µm fraction. Therefore, because the magnetic conditioning of Zn flotation feed cannot impact plant ore feed grade the hypothesis is that the magnetic conditioning is reducing the fine mineral from downstream processes, like filtering and thickening, returning to the plant feed in the recycled process water. This hypothesis is consistent with plant observation of dirty concentrate thickener overflow and measurements of solids in the overflow, as well as the average % Zn grade in cyclone overflow that correlates with the magnetic conditioning ON and OFF days. This paper presents these plant test results.CITATION:Smiles, R and Lumsden, B, 2018. Improving fine sulfide mineral recovery in Independence Group’s Jaguar Mine zinc circuit, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 433–440 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018