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A study of the bacterial oxidation of naturally occurring high-purity sulphide minerals (FeS2, Fel_xS, CuFeS2, Cu2S) has been conducted using a mesophilic strain of T. 6ejtAooLcdcth4. As well as metal analyses and solution pH, partitioning of sulphide sulphur into elemental sulphur and sulphate ion has been monitored. Partially oxidised sulphide substrates have been characterised at regular time intervals by X-ray diffraction methods and extra-cellular organic compounds reporting into leach solution have been identified by'thin layer chromatography. The results indicate that the S¦/SO4 2 partitioning of the sulphide substrates is independent of cell inoculum size and initial pulp density and varies with solution pH, Eh, leaching time and mineralogical properties of the individual sulphide minerals. The signifi- cance of results for applications in selective flotation, coal desulphurisation and agglomera- tion has been outlined.

Jan 1, 1984

By Y Xu, T Rowles, B Dareeju, A Dissanayake

Recent updates on tailings dam design guidelines require analysis of undrained (short-term) stability with the application of the SHANSEP model. The SHANSEP model, which was originally developed for alluvial soils, predicates that the Undrained Shear Strength (Su) increases with increasing effective stress. Residual soils by their nature do not necessarily follow this relationship. This paper examines an alternate method to define Su over a range of effective stress conditions for residual soils. Residual soils, formed by weathering of their parent rocks, are generally micro-structured in nature. The microstructural features, such as interparticle bonding, play a fundamental role in stress-strain behaviour of the residual soils. As interparticle bonding is independent of effective stress and void ratio, the undrained shear strength of residual soils is expected to be less dependent on effective stress than alluvial soils, especially at low stress levels. A series of triaxial tests conducted on residual soils, however, indicated that the undrained shear strength and the undrained shear strength ratio (Su/σv’) are to a degree dependant on effective stress. It was found that the undrained shear strength ratio is significantly higher under low stress levels and progressively reduces with increasing effective stress. Based on the laboratory testing data, a strength function with varying undrained shear strength ratios can be developed for the residual soils under the stress range anticipated for a design of a tailings dam. This includes capping the input undrained strength at lower effective stresses based on the drained (effective) and minimum undrained strength. The Factor of Safety (FOS) calculated for the embankment utilising the traditional limit equilibrium (LE) method indicated the application of undrained strength function for the residual soils can provide a significant optimisation for the embankment design compared to adopting a constant undrained shear strength ratio or constant undrained shear strength in the design.

Jul 1, 2021

By A De, B Palmer, rade, P Stowasser, A Fanning

Mining and tunnelling share many commonalities (eg confined working environments, excavation equipment and processes), but of significance is an overarching commitment to provide safe work conditions and environments. This includes reducing exposure to hazardous airborne contaminants such as dust and fumes, in particular Respirable Crystalline Silica (RCS) and Diesel Particulate Matter (DPM), with methods that are environmentally sustainable. In mining, wet methods are common to suppress airborne contaminants, however these methods are reliant on water availability, can be less effective for respirable dust, can have implications for environmental water contamination and can increase maintenance on mining equipment. In contrast, the use of dust scrubbers that provide filtration of airborne contaminants are well established in the tunnelling industry and frequently used to provide spot extraction (dust control at the source) and act often as a complement to the main ventilation system. This paper sought to learn more about the advancements in tunnelling that could be readily applied to mining to improve health outcomes. The paper includes a review of literature and legislation related to health and sustainability and interviews with three respected, and experienced managers from the global tunnel construction industry. It is from these interviews that the focus of the paper turns to Sydney’s WestConnex underground tunnel network and the success of stage 3A M4-M5 construction link. The findings position dust scrubbers as integral to the overall project success as they enabled a Tunnel Production Line (TPL), where multiple stages of construction could take place simultaneously by controlling high volumes of dust at the source. The findings also suggest efficiencies of using mobile scrubbers, both track mounted and hydraulic stepping systems, to accompany road headers and other equipment throughout the excavation process. The findings have transferable applications to underground mining processes in which workers are exposed to high volumes of dust (eg drill and blast) or situations in which dust control at the source, mobility and flexibility offer value (eg room and pillar mining).

Apr 16, 2024

In 1987 the control strategies at the then ZC Mines' New Broken Hill Consolidated concentrator were a miscellaneous mixture of computer hardware and technology for ISA, grinding and residue thickener control. Field instrumentation was based on current-to-air technology of approximately the 1960s. Decisions were made to rationalise computer and field instrumentation technologies; the object being to consolidate control loops into one system to enable expansion of the system to include all facets of plant operation. The first stage was to install a DEC Micro PDP 11/23 computer and serial line communication as recommended by AMDEL Ltd, for the ISA system, as discussed by Walsh and Freeman (1988). The second stage was to select and install a distributed control system for the centralisation of the control loops into one system, and to replace field instrumentation with state-of-the-art technology. This paper deals with the second stage of the rationalisation, in an attempt to give an insight into what is required when personnel are faced with such a decision, details of costs involved in keeping a system functioning and utilised; and the requirement to train personnel for acceptance of further control strategies.

Jan 1, 1991

By S Mundell, J Armstrong, M Evans

"Automation is a common goal within the coal industry for reasons such as efficiency, reliability and sustainability. However, it requires standards and frameworks so business systems can communicate effectively. Automation of sample analysis processes has been difficult to establish due to a lack of direct business system communication between commercial laboratories and mining companies. This has resulted in manual procedures that have contributed to problems relating to analysis instructions, sample identification, results formats and visibility of status.These problems result in loss of data and confidence in data validity, loss of process efficiency and inability to react to issues. An Australian Coal Association Research Program project (Evans, Armstrong and Arboleda, 2014) has addressed these issues through the Coal Quality Data Exchange methodology for direct business system communication between coalminers and commercial laboratories to optimise the transfer of coal quality data.The benefits to the coalminer of the framework are:increased clarity and auditability of what is being sent to the laboratory and what was requestedreduced potential for error introduced through manual transcription tasksincreased speed of loading of analytical results to the customer Geoscientific Information Management Systemimproved turnaround time for analytical resultsincreased knowledge about what took place in the laboratory with respect to the determination of the analytical resultsincreased visibility of the status of a ‘work order’. The benefits to the technology companies and commercial laboratories is a common framework on which to build a sustainable solution that gets away from the multitude of formats catered for today and time consuming manual processes. The common framework significantly advances the future possibilities for the automation of sampling and analysis processes in a production environment.CITATION:Armstrong, J, Mundell, S and Evans, M, 2014. Automating communications between laboratories and mines – a case from the coal industry, in Proceedings Ninth International Mining Geology Conference 2014 , pp 351–360 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 18, 2014

By D Cooke

In 2010, Kalgoorlie Consolidated Gold Mines (KCGM) was Australia’s largest gold producer, with total annual production of 788 000 ounces. Of the gold produced by KCGM in 2010, 95 per cent was extracted from the Fimiston open pit, also known as the Superpit. The Fimiston operation encompasses the historic Golden Mile, from which more than 55 million ounces of gold have been extracted from the world-class Fimiston lode style mineralisation.The operational performance of the KCGM Fimiston open pit was reviewed for the period between 2005 and 2010. Key performance metrics reviewed included mined tonnes and grade, cost per ounce of gold produced and the mine to mill reconciliation trends. The years 2007 and 2008 were characterised by a decline in performance against key performance metrics. The ore zones were diluted, with the excess tonnes mined resulting in lower grade and an increase in the cost per ounce. Poor reconciliation between ore mined, the ore reserve model and the grade control polygons was also observed.A series of improvement initiatives were implemented in late 2008. As a result of changes made to the grade control and mining practices, the site performance recovered. Unplanned dilution was reduced, which had a positive impact on mined grade. The lower tonnes combined with higher grade reduced the cost per ounce to below budgeted levels in 2009 and 2010, enhancing the profitability of the operation. The operational performance between 2005 and 2010 was compared to the turnover statistics for the KCGM geology department over the same period. Turnover accelerated between 2005 and 2007, peaking at an annualised rate of 43 per cent. With the onset of the Global Financial Crisis and the implementation of retention initiatives, turnover reduced significantly between 2008 and 2010. A strong consistent correlation was observed between the turnover trends in geology and the performance of the grade control function and resultant site metrics.The cost of turnover is known intuitively, however, rarely quantified. To evaluate the benefit of the improved performance, a detailed financial model was used to quantify the impact of the grade control function. In 2010, the headgrade exceeding budget by just four per cent contributed an additional A$24 M of value to KCGM. In contrast, if the 2008 performance had been replicated in 2010 (-9 per cent on headgrade), the result would have removed A$61 M in value from the business. The KCGM experience between 2005 and 2010 demonstrates the value of human capital in a mining operation and the importance of a high performing geology grade control team to the profitability of a mining operation.

Aug 22, 2011

By R Baumgartner

The Canahuire deposit is a recently discovered Au-Cu-Ag epithermal deposit in Southern Peru. A geometallurgy program is a key study element of the project Feasibility study. Metallurgical, mineralogical, and comminution studies have been completed over a suite of samples, spatially distributed among the various geological/ore domains. The early stage of Canahuire presents challenges as there is a lack of metallurgical information to guide geometallurgical sampling, in contrast with an established deposit at a more advanced stage of development or mining. Nevertheless, the available information will assist in the development of geometallurgical domains for Canahuire in order to ensure that future metallurgical, mineralogical, and comminution test work is representative of the deposit variability. This supplementary knowledge will be able to predict important metallurgical parameters which will be incorporated into a geometallurgical model to spatial predict material types, metallurgical recovery and through put. The information obtained will be a valuable addition to the future mine plan, influencing process design, engineering design, plant operation, operating and capital costs, and ultimately will reduce project development risk.

Sep 5, 2011

By G J. Showers, P Botman, A G. Hunt

Iron Road Limited (Iron Road) is currently evaluating the feasibility of producing 21.5 Mt/a of high-grade (>66 per cent Fe) magnetite concentrate from a 3.7 Bt resource (JORC) located at Warramboo on the central Eyre Peninsula in South Australia. Bulk concentrate can be produced via a conventional grind and low-intensity magnetic separation flow sheet. Due to the comparatively coarse magnetite liberation size (106 µm), consideration was given to enhancing both the grind economics and coarser product sizing via gravity separation.This paper outlines the test work, flow sheet design and engineering design of a gravity beneficiation circuit (GBC) conducted by Mineral Technologies for Iron Road. The resulting circuit optimisation necessitated mass balance simulation by Iron Road’s SysCAD model to quantify the resulting changes in mill recirculation load. This included the determination of project-critical grinding power and energy requirements with and without the GBC installed into the primary ball mill classification circuit. The outcome of this work was the design of a GBC, including spirals and up-current classification, which led to a substantial reduction (33 per cent) in ball mill recirculating load and power requirements, together with a favourable coarsening of final product size due to the relatively coarser gravity concentrate. This has led to a significant reduction in project design capital and operating costs. A further benefit of this approach is increased recovery of (paramagnetic) hematite and lesser titano-hematite via gravity separation compared to an all-magnetic separation approach.CITATION:Hunt, A G, Showers, G J and Botman, P, 2015. Test work and design of a gravity circuit for Iron Road’s Central Eyre Iron Project, in Proceedings Iron Ore 2015, pp 139–142 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By W Curlewis, D Hake, Z Cuthbert

The South Island Line (East) will be a medium-capacity railway covering approximately 7 km from Admiralty Station to South Horizons Station on the south side of Aberdeen Harbour in Hong Kong, with intermediate stations at Ocean Park, Wong Chuk Hang and Lei Tung.South Island Line (East) Contract 904 project is located on the island of Ap Lei Chau at the southern side of Hong Kong island and requires extensive construction works to be completed in close proximity to the existing residential estates of South Horizons and Lei Tung. The project also has areas of significant cultural heritage, including 18th and 19th century temples and historical gravesites. Owing to the site access constraints and location for the project, detailed planning and methodology innovations have been required to ensure the most effective and responsible means of delivering the project works. To excavate the tunnels using drill-and-blast techniques in these restricted locations, the maximum instantaneous charge weight that could be fired while blasting was severely limited. To overcome these restrictions, the project team developed and pioneered the use of ‘deck loading’ in Hong Kong to minimise the impact of blasting operations and has successfully implemented double- and triple-deck blasting operations during the completion of tunnel excavation works.Upon completion of the drill-and-blast excavation, the tunnel lining works were completed using both in situ concrete lining with travelling forms and permanent shotcrete works.CITATION:Curlewis, W, Cuthbert, Z and Hake, D, 2014. SIL904 Hong Kong – Drill and Blast Tunnels, station blasting innovations (double- and triple-deck blasting) and lining solutions, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 21–28 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

"Geometallurgy is a discipline that seeks to improve the sustainability of the extraction of metals and minerals by promoting the smarter use of non-renewable resources, better energy efficiency and greater use of renewable energy. To achieve these goals, development of innovative technologies and approaches are being developed along the entire commodity value chain, starting with exploration and extraction and extending to reuse and recycling. This paper discusses the geometallurgy of industrial minerals with special emphasis on kaolin, a versatile industrial mineral applied in ceramics, paper, paint, plastics, rubber, pharmaceuticals, cosmetics, ink, sealants, adhesives, sanitary ware, glass fibre, toothpaste, animal feed etc. Aspects of kaolin extraction in south-west UK are analysed from a geometallurgical perspective. While geometallurgy already features in kaolin extraction, its role can be significantly expanded by combining advanced in-pit characterisation and orebody modelling with integrated planning and control of the refining and calcination process. This paper highlights the importance of innovation in realising the full potential of geometallurgy.CITATION:Glass, H J, 2016. Geometallurgy – Driving Innovation in the Mining Value Chain, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 21–28 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By A B. Bayooke, A C. Robertson

In terms of underground tunnelling in metres advance per capita, Australasia compares well with the best world performers. This is because of the large number of metalliferous mines, coalmines and civil tunnelling projects, with the Australian tunnel advance for civil and mining projects exceeding 625?km/a. In terms of hard rock quarry extraction, Australia produces approximately 200?Mt/a of aggregates, roadbase, fill material and specialist rock products from its quarries, which equates to approximately 8?t/capita. Australian mining and tunnelling contractors are also of world standard and are used to excavating in a variable range of ground conditions in a competitive environment. One author has been involved in tunnel and underground space planning and quarrying in Australia for the past 25 years and predicts that, over the next 20 years, there will be a major swing towards underground space for commercial uses. This paper identifies the potential uses of underground commercial excavation and the planning and geotechnical challenges for the future. Underground quarrying creates new opportunities to extend existing quarries within their urban footprint with minimum impact on the surrounding community. Investigations by the authors reveal that there are very few cities in the world that actually incorporate underground space planning in their city plans. However, cities such as Helsinki have been planned in detail to utilise the rock resources beneath them. Brisbane is used as a case study for a practical application of commercial underground space and underground quarrying in Australia.CITATION:Bayooke, A B and Robertson, A C, 2014. Geotechnical challenges for underground commercial space and quarrying in Australia, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 317–322 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By A G. L Pratt

Operational readiness is a commonly used term in mining and many other industry settings. However, translating this term into a coherent scope of work that is practical and meaningful is a challenge faced by many mining projects. This inhibits the allocation of resources to the work and its completion. The problem is with understanding how the terminology applies to establishing a mining operation. Resolving this problem requires clarity around what operational readiness means for a mining project’s transition to operations and who owns the tasks of completing operational readiness. The motivation for resolution of this problem is in appreciating the consequences arising from any lack of clarity in definition of this task, the timing of the work, and ownership for its completion. In broad terms, these consequences amount to an erosion of value at a critical time for both the new mine and the company and shareholders. This situation often arises where operational readiness is not adequately addressed in project’s study phases. As a result, neither time, resources nor money are adequately provided to complete the work required. In other cases, operational readiness is sometimes assimilated with the delivery of the project’s physical assets by the project’s construction team, rather than aligned with the establishment of the operating team to deliver the desired operational outputs. This paper argues that operational readiness starts in a project’s study phases and flows through into the start of operations. The definition of operational readiness is discussed as a task, and a model for its planning and completion is presented. This discussion includes assigning ownership for operational readiness planning and delivery to the General Manager of a new operation and the operations leadership team, who are central to the success of this work. After all, the reputations of this leadership team depend on the performance of the operation in its first few years. The author’s work over the last 20 years, leading operational readiness programs and the preparation of feasibility studies for mining projects, has provided the insights and evolution of ideas that are central to this paper. Operational readiness is fundamentally directed at ensuring a new mining operation gets away to a successful start and builds a solid foundation for the future of the mine/operation/province. It requires clarity of purpose, ownership and coordination by people in the operating team, and their preparation of the requisite process definition and establishment of the significant relationships required for operations. Without its successful completion, it is unlikely the new operation will meet and sustain its start-up targets. This paper discusses a practical approach to operational readiness for mining projects.

Mar 29, 2023

By S Hapugoda, J R. Manuel, M J. Peterson, A Poliakov, E Donskoi

The occurrence and deportment of manganese in a number of ferromanganese and Mn-bearing iron ore samples from supergene-upgraded deposits, as well as from magnetite banded iron formation (BIF) and magnetite skarn deposits, was characterised in order to provide a basis for improved understanding of the processing characteristics of different ore types and investigate the potential for development of a robust geometallurgical classification for Mn-oxide ores. An understanding of the Mn mineralogy in mixed Fe-Mn deposits is necessary to inform any attempt to separate the Fe and Mn during beneficiation and to understand and predict the behaviour of lump and fine ore products during processing.A suite of analytical techniques was utilised, including hand sorting of lump ore particles, optical microscopy, X-ray fluorescence (XRF)/inductively-coupled plasma mass spectrometry (ICP-MS) chemistry, X-ray diffraction (XRD), scanning electron microscopy (SEM)/electron probe microanalysis (EPMA) and gas and solid phase pycnometry, in order to elucidate manganese mineralogy, mineral chemistry and mineral textures. Manganomelane group minerals (eg cryptomelane, hollandite), pyrolusite and lithiophorite were the most common manganese oxides in the samples examined. From the microprobe work, there was evidence of probable substitution of Mn, as well as Al and Si, into the structures of goethite and hematite. Manganomelane minerals were often intimately associated with goethite, in particular, and a clarification of this association and the associated Si and Al impurities is fundamental for improved understanding of beneficiation and sintering behaviour of Mn-oxide ores. Due to the poor or very fine crystallinity of some supergene manganese deposits and of some Mn oxide minerals, in particular the extent of overlapping peaks and their variable mineral chemistry, XRD was a problematic technique to equivocally determine Mn mineralogy.For lower-grade, earthy, poorly microcrystalline ores the mineralogical and textural association between mixed Mn, Fe and Al (¦ Si) phases was also critical. The deportment and potential separation of these elements in these deposits, especially Al, was complex, as they were characterised by forms of æhydrousÆ cryptomelane with higher levels of Fe-Al-Si substitution, as well as intimate intergrowths of ochreous-earthy goethite (probably aluminous in part) with cryptomelane, lithiophorite and/or kaolinite.Trace amounts of alkali elements in ferromanganese deposits were considered likely to be preferentially structurally associated with Mn oxides, while lateritic deposits with significant amounts of lithiophorite could contain elevated levels of deleterious impurities; Co and Ni in particular.A combination of solid and gas phase pycnometry proved to be a useful technique for broadly discriminating hematitic, goethitic and mixed Mn oxide-goethite lump particles based upon differences in their envelope and apparent densities. Based upon these preliminary results and ongoing Raman spectroscopy work on manganese deposits sensu stricto, Raman spectroscopy is a technique considered to have promise during targeted research to better link the optical and compositional properties of ferromanganese ore particles. CT-scan (computed tomography scan) analysis could also be combined with Raman spectroscopy and pycnometry to link mineral composition, mineral texture, ore particle textures and particle porosity/permeability to the high-temperature processing behaviour of lump and fines products.CITATION:Peterson, M J, Hapugoda, S, Manuel, J R, Donskoi, E and Poliakov, A, 2013. Textural characterisation of manganese minerals to improve the geometallurgical characterisation of ferromanganese and iron ores, in Proceedings Iron Ore 2013 , pp 281-300 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By W Zeng, D Walker, D Cai, E Baafi

"The efficiency of the truck-shovel haulage system is significantly influenced by the truck fleet size. A discrete event simulation model with 3D animation has been developed to estimate the productivity of a truck-shovel network system, shovel efficiency, truck cycle time, truck utilisation and the optimal fleet size. The simulation model considers the dynamic variability of traffic conditions and also the truck as an individual entity. The resulting truck cycle time was found to be realistic and thus providing a better tool for strategic mine planning.Citation:Zeng, W, Baafi, E, Walker, D and Cai, D, 2016. A 3D Discrete Event Simulation Model of a Truck-shovel Network System, in Proceedings Ninth AusIMM Open Pit Operators' Conference 2016, pp 265–273 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 15, 2016

By S Norman

The Water Delivery Alliance (WDA) was established to design, construct and commission the pump station and desalinated water delivery pipeline to link the desalination plant on the Kurnell Peninsula (constructed by others) with the existing distribution network at Erskineville, Sydney, Australia. The WDA consisted of McConnell Dowell Corporation Ltd (Macdow), Bovis Lend Lease Pty Ltd (BLL), Kellogg Brown and Root Pty Ltd (KBR), Worleyparsons Ltd (WOR), Environmental Resources Management Group Inc (ERM) and Sydney Water Corporation (SWC).Sydney’s Desalination Project is one of the initiatives to secure Sydney’s water supply against the effects of climate change, population growth and drought. The desalination plant, 100 per cent powered by renewable energy, can supply up to 250 million litres of water per day (mld), which is up to 15 per cent of Sydney’s water needs. The project involved the construction of an 18 km pipeline with an ultimate capacity of 500 mld to accommodate any future increase in the output of the desalination plant.The Alliance procured three full-face tunnel boring machines (TBM) from Herrenknecht AG to construct the 6.5 km of tunnel that would provide a conduit for the DN1800 welded mild steel cement mortar lined (MSCL) pipeline at a number of locations along the route. Nineteen shafts and 16 tunnels were required to complete this work.Crucially one of the TBM drives involved construction of a tunnel into Botany Bay under protected marine life habitats; enabling the connection of the MSCL water carrier pipeline into the dredged section of pipeline underwater, approximately 800 m off-shore in Botany Bay.This paper details the retrieval of the 17.4 m long TBM from the ocean floor upon completion of the Botany Bay tunnel allowing for subsequent use on the Project. Elements covered in the paper include the 835 m tunnel, design and construction techniques for the tunnel and recovery, and details of the methods used to install the DN1800 water carrier pipeline.

Mar 8, 2011

By A Mooney, G Balog, P Burns, R Brooks

This paper outlines the rationale for the location of the crusher, geotechnical analysis and basis of ground support design, design and scheduling of the chamber and supporting excavations as well as the operational outcomes and lessons learned. Contributions from mining operations, planning, geotechnical and infrastructure teams enabled the Crusher Station One excavation to be completed on schedule, with opportunities taken for underground mining and infrastructure to work safely in parallel to deliver crusher station infrastructure on schedule. Installation of crusher infrastructure was ongoing at the time of writing.

Mar 15, 2021

By G Harbort

Traditional engineering design for flotation circuits use the “Rule of Thumb” approach. Typically this uses a nominated maximum head grade for design. A scale-up factor is applied to laboratory flotation tests for residence time. This scale-up factor is usually based on a designers experience at other flotation sites and may or may not be relevant to the circuit being designed, or the flotation equipment being used. A small number of locked cycle tests are assumed to represent the ore body and the results of these are often used for financial analysis, independent of changes in mine plan throughput and mineralogy.The engineering “Rule of Thumb” approach is only strictly accurate where there is very little variability in throughput, head grade and mineralogy. It may provide accurate design for mature established operations where a brownfield expansion is being considered but is unlikely to provide accurate design for a new, greenfield site.The use of geometallurgical modeling with floatability component simulation provides a design methodology with significantly less associated risk. The use of geological data for optimisation of operating plants has become a significant part of the modern process mindset. The underlying principle is to use spatial metallurgical information to drive production planning, mine planning, blast design, blending strategies and plant set-up. At a design stage the process designer can use geometallurgical information to evaluate bottle necks and potential design flaws and propose the best investment strategy for the project benefit.This paper details the geometallurgical characterisation of the Andash deposit and methodology used to review the project’s detail design and projected production.

Aug 8, 2011

By M A. Rhamdhani, R Z. Mukhlis

Removing the ledge formation in the Hall-Heroult cell during the electrolysis process may significantly reduce the energy requirement of the aluminium production process. In the absence of the ledge, however, the sidewall-material types become heavily restricted since the cryolite is very corrosive at the electrolysis temperatures. This paper study the corrosion behaviour of sintered nickel ferrite, nickel aluminate, and magnesium aluminate refractories (as possible candidates for sidewall material) in molten aluminium and cryolite melts with various alumina content at 980°C. Immersion tests of refractories with various porosity were conducted to assess the suitability of the refractories in the corrosive environment of the electrolysis cells. Microstructural change of the refractory after immersion were analysed using secondary scanning electron microscopy (SEM). Sampling of the melts were taken at 0, 10 min, 30 min, and each hour up to 6 hrs, and subsequently analysed by Inductively Coupled Plasma (ICP) spectroscopy. Based on the projected concentration of the refractories constituents in the melts, it was predicted that the corrosion rate of NiFe2O4, NiAl2O4 and MgAl2O4 in cryolite with 11 wt per cent Al2O3 were 461 × 103, 1.03 × 103, and 798 × 103 cm/a, respectively. Much lower corrosion rate of 2.3 cm/a for NiFe2O4, 2.6 cm/a for NiAl2O4 and 0.3 cm/a for MgAl2O4 were predicted if the refractories in contact with aluminium melts. Erosion played an important role in the corrosion as the concentration of the refractory constituents in the melts were beyond its solubility limit. It is therefore crucial to increase the densities of the refractory and improve its wetting characteristics.

Aug 21, 2024

By Y Peng, C Burns, Y Mu, R A. Lauten

In both laboratory flotation experiments and from analysing the composition of the lead concentrate at the Boliden Tara lead-zinc mine in Ireland, it has been found that F-250 may replace cyanide as a pyrite depressant. Replacement or reduction of the cyanide consumption is highly desirable from a safety perspective given the toxicity of cyanide. Scrutiny of results from the plant trial indicate that F-250 is less efficient as a cyanide depressant when the flotation feed contains high levels of pyrite. Statistical analysis of the results does not capture this trend, illustrating a need to collect more data at higher pyrite ore levels. A recent model proposed for biopolymer-induced pyrite depression is reviewed and discussed next to the suggested mechanism for pyrite depression via cyanide. Review of the interactions causing pyrite depression point to different manners in achieving depression. In light of the less efficient F-250 pyrite depression at high pyrite levels, it is speculated if the two depressants may act synergistically at high levels of pyrite in the feed. CITATION:Lauten, R A, Burns, C, Mu, Y and Peng, Y, 2018. Pyrite depression at Boliden Tara using F-250 – a biopolymer, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 385–392 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By I Swane, R Rait, A Robertson

Geochemical assessment of mine waste materials prior to commencement of a proposed mining operation is a fundamental component of mine feasibility studies and the regulatory approvals process. Static and kinetic geochemical test methodologies are widely used to predict the geochemical nature of mine waste materials and to develop strategies for managing potentially æhostileÆ materials. These data can also be integrated with data from other fundamental studies such as hydrogeology to predict specific environmental outcomes and potential impacts at mine closure and post-closure.A case study is presented for a proposed open pit gold mine in Mongolia, which illustrates how geochemical, hydrogeological and groundwater quality data can be used as part of a geochemical modelling process to predict the final pit lake water quality over time. A series of static and kinetic test geochemical test programs were completed and acquired data integrated with hydrogeological and groundwater quality data provided by the proponent. A widely used geochemical modelling program (PHREEQC) was used to develop the geochemical model and predict water chemistry in the pit void after mine closure. Sensitivity analyses were completed to explore the effects on the model output of groundwater to leachate water ratio, pit wall rock type and climate.Modelling has indicated that pit void water should be pH circum-neutral at mine closure and should remain within Mongolian and World Bank water quality guideline limits under the modelled simulation most likely to occur in the field. Final void water salinity is expected to increase eight fold over 14 years after end of mine life due to a continuous flux of salts (particularly sulfate salts) into the pit lake whilst the pit lake volume will remain relatively constant due to evaporation and a slow recharge rate. Dissolved metal and sulfate salt concentrations in pit water are also predicted to increase over time and could be moderately elevated compared to applied water quality guideline values. Some of the metal concentrations, however, may be lower as these would be expected to precipitate at circum-neutral pH and greater. Recommended additional assessment work on the project when mining commences includes determining the magnitude of adsorption and co-precipitation of metals occurring in the pit void water/sludge system.CITATION:Robertson, A, Rait, R and Swane, I, 2013. Geochemical assessment of mine waste materials and prediction of final pit lake water quality at a proposed gold mine in Mongolia, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 165-170 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013