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By Green GR

Description of two methods developed at Sulphide's Cockle Creek Plant as part of a site energy reduction program. The two case studies are:

Jan 1, 1985

By C E. Woolley, H Jebaliya, J Foster

The East wall of the Kalgoorlie Consolidated Gold Mines Fimiston Open Pit (KCGM Superpit) has a history of wall instabilities impacting mining operations; the most significant of which occurred in May 2018, when more than 1 Mt of rock dislodged over six, 30 m high bench stacks and impacted the pit floor. Since 2011 approximately 1.250 Mt of material has fallen from the East wall at Fimiston Pit across three failure events (2011, 2018 and 2020). Each failure has been associated with major structures intersecting the pit walls: the Fiji Fault, the Australia East Secondary Splay Fault and the EWD3 Fault. In each instance the trigger for failure has been transient pore pressure in the pit walls. Northern Star will mine a cut back behind the failure area over a vertical distance of 180 m. Cut back mining will include the extraction of a remaining in situ wedge, which is assessed as kinematically able to fail, and a subvertical failure backscarp in Stage 1. A substantial amount of rill material from the 2018 and 2020 failures will be extracted in Stage 2. This paper presents the methodology in use to mine Stage 1 of the cut back, safely, through this potentially high-risk area, detailing the specific mining methodology employed, the controls put in place and the monitoring required. Day-to-day monitoring will be undertaken using the already installed slope stability radar and will feed into a daily assessment of activities which may be undertaken in the cut back area. Initial activities will focus on eliminating the potentially unstable wedge and vertical backscarp with use of innovative drill and blast techniques/products and the extensive use of remote capable equipment to limit personnel exposure.

Jun 22, 2022

By P Chapman, B Moosapoor

The objective of this paper is to present the potential applications of geostatistical analyses in planning CPTu investigations, as well as interpolation of CPTu data. The paper presents a case study of a geostatistical analysis of CPTu data undertaken between 2004 and 2017 for an upstreamraised TSF located in the Goldfields region of Western Australia. An initial model is developed using the 2004, 2009 and 2017 CPTu data. The model is used to predict in situ cone tip resistance (qc) measurements, as the interested primary variable, at the selected locations where 2019 CPTu were undertaken, and the results of the prediction and the actual data are compared.

Jul 1, 2021

By Lauricella P. F, Hendri D

In the Mesel sediment-hosted disseminated gold deposit, the spatial distribution of hydrothermal alteration is controlled by steeply dipping faults and shallowly dipping lithologies. Hydrothermal alteration of carbonate rock is characterised by decalcification, dolomitisation and silicification. Intense argillic alteration occurs in a laccolithic andesite intrusion adjacent to decalcified and silicified carbonate units. Sulphide minerals (pyrite, realgar, orpiment, stibnite and cinnabar) accompany hydrothermal alteration and precious metal mineralisation. The trace elements Ag, As, Sb and Hg are zoned spatially throughout the deposit. Mesel contains a mineable gold reserve of 7.8 million tonnes at 7.3 g/t Au. Gold mineralisation is preferentially localised in carbonate rocks adjacent to and beneath the andesite intrusion. The ore body consists of a central, near-vertical, high grade "feeder" system flanked by tabular, inward dipping, moderate grade "ouflow" zones. Mineralisation is controlled predominantly by two steeply dipping faults with high grade (>10 g/t) gold zones centred about structural intersections and fault splays. Gold is submicron size and locked in very fine grained (

Jan 1, 1995

By R Dimitrakopoulos, C Paduraru

The optimisation of mine complexes and related value chains is a challenging problem due to the simultaneous presence of a highly-dimensional decision space, integer decision variables, non-linear constraints and recovery functions, as well as geological and market uncertainty. In addition, if the uncertainty is revealed progressively, then decisions need to continuously adapt to new information, which poses additional challenges. Stochastic dynamic programming is a well-known class of methods for addressing problems where a decision-maker reacts to new information. While simplistic applications of dynamic programming using exact representations would be intractable for any realistic mine planning problem, new dynamic programming methods using approximate value function representations have been successfully implemented in the past to address problems of similar complexity. This work formulates the problem of mine complex optimisation as an approximate dynamic program and presents an application of the resulting method to a gold-copper deposit.CITATION:Paduraru, C and Dimitrakopoulos, R, 2014. Mineral supply chain optimisation under uncertainty using approximate dynamic programming, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 415–422 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By T Gibbons, M Korte, C Brent, K Runge

The Barrick Osborne concentrator has gone through a number of upgrades since commissioning and steadily increased production from the original 119 t/h design capacity to 265 t/h milling throughput in 2008. This was achieved incrementally over several years, by maximising operating efficiencies, in order to minimise capital expenditure, and take advantages of economies of scale; but more importantly it was reached with no measurable loss of recovery. Osborne currently processes a blend of under- ground with open pit material from the nearby Trekelano deposit. Following primary/secondary crushing, the material is processed through a rod/ball mill grinding circuit ahead of rougher/scavenger flotation that produces a copper concentrate.Osborne was seeking a further increase in plant throughput of the order of 15 per cent, but at more sustainable levels of secondary crusher plant utilisation. In early 2008, Osborne contracted Metso Minerals Process Technology Asia-Pacific and South America (MMPT) to review the entire process from run-of-mine feed to final copper concentrate. This review would be done concurrently, with surveys of both the crushing/ grinding and flotation circuits being performed at the same time. The outcome would be a steady-state model of the complete flow sheet allowing the crushing/grinding model to interact with the flotation circuit model such that overall process optimisation was possible. Two key outcomes for the operation are exploration of the operating limits of the currently installed plant, and projection of the logical next stage of potential capital plant expansions. This paper covers Part B or the flotation component of the project. A separate paper discussing Part A or crushing and grinding is also being presented at this conference. Surveys of the Osborne flotation circuit were performed along with a comprehensive review of the cell characteristics including measurements of the gas and froth phases of individual flotation cells. These data resulted in a size-by-size floatability component model of the complete circuit. This circuit model was then used to perform steady-state simulat- ions to evaluate options to improve both overall circuit and individual cell performance. The grinding circuit model discussed in a separate paper or Part A of this project was then used interactively with the flotation circuit model to recommend the best operating regime to maximise overall efficiency. For example, the balance between increased crushing and grinding costs versus higher copper recovery and final concentrate grade. Due to changes in market conditions in the fourth quarter of 2008, the focus was shifted to prioritising operational changes rather than capital expansion modifications, in order to improve circuit performance.

Jan 1, 2009

By H Lehtonen, H Mansikkaviita

In primary copper smelters, the received copper concentrate and other materials contain a certain amount of moisture, ranging from six to 14 per cent. Moisture in wet concentrate has a negative effect on the performance of the smelting furnaces when it is fed directly to the furnaces, namely increasing the energy consumption and the off-gas flow. There are several drying technologies available for drying copper concentrate, varying from direct heated rotary dryers and flash dryers to indirect heated steam dryers. Application of steam dryers has changed the drying process for copper smelters. Produced from a waste heat boiler, steam as heating medium enables plant-wide heat utilisation. Fossil fuel used from outside sources to remove water is no longer required and the combustion chamber is not required. In addition special attention has been paid to overcome the known problems of pollution emissions, excessive wear, clogging and frequent maintenance. The Kumera steam dryer is featured with many advantages based on principal improvements in reducing tube element wear and increasing drying efficiency. Thus, it has been considered as the first choice for those smelters where steam is available.

Jan 1, 2006

By D Nieuwkerk, V J. Absolon

"Screw press technology is an innovative approach to tackling the growing pressure to conserve water and minimise the environmental impact of mineral tailings disposal. The principles of the technology have been known for a considerable period of time in non-mining applications such as water treatment, wastewater (municipal sludge), as well as in the paper and chemical industries for dewatering solids, particularly those containing clays.The screw press represents a viable niche technology for filtering fine and high-clay tailings, without the prior thickening stage, and is capable of producing a filtered product that is sufficiently consolidated and dry enough to provide a product suitable for conveying and dry stacking.The Ishigaki screw press was introduced in 1990 and key features are: continuous operation and excellent availability low wear to plant acceptable flocculant consumption low carbon footprint and low noise levels fully automatic.These features lead to simpler plant layouts, easier maintenance, smaller spares inventories, reduced wear, smaller footprint and overall lower capital and operating costs.The amenability of a particular tailing stream to treatment by screw press technology may be determined by test work. Two pilot plant studies are described where this technology has been applied in the mineral industry being flotation tailings from a rare earth (RE) mineral concentrator and coal tailings. In addition, preliminary details are given of an ACARP sponsored research program titled ‘The application of screw press filtration in tailings dewatering’.CITATION:Absolon, V J and Nieuwkerk, D, 2014. Innovative use of screw press filtration in tailings dewatering plant design, in Proceedings 12th AusIMM Mill Operators’ Conference 2014, pp 449–456 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 1, 2014

By F Wu, H Wang, W Chen

A pressurisation method with multiparallel fans has been adopted at HongLiuLin Coalmine to control the significant external air leakage through the goaf area of coalface 15207. Potential damaging effects of large external air leakage on a coalmine’s ventilation system are analysed according to the current air leakage status caused by the exploitation of shallow-covered coal seams. The use of pressure balanced ventilation to prevent external air leakage through goaf areas is introduced. The calculation of ventilation network of HongLiuLin Coalmine shows that the air resistance of an external air leakage branch through a goaf area and the air pressure drops from the intake slope to the working face can be adopted to determine the values of pressure to be increased by regulating fans and airflow controlling parameters of regulators. By investigating airflow requirements of the pressure-balanced area as well as the performances of the auxiliary fans currently used in the coalmine, the number of pressurisation fans needed is fixed. The expected result is achieved after the pressurisation method has been carried out, which can be helpful for other coalmines to handle similar problems.CITATION:Wu, F, Chen, W and Wang, H, 2015. Multiparallel fan method to prevent significant external air leakages through a goaf area of a shallow covered coalmine, in Proceedings The Australian Mine Ventilation Conference, pp 267–270 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By C Fischer

The introduction of digital communications technologies into the underground mining industry, in both coal and hard rock mining, has enabled high bandwidth applications to be applied in the mining industry. Digital networks based on 802.11 b/g/n open Wi-Fi standards have allowed numerous applications to be run over a single communication backbone. One of the many important applications is the tracking of personnel and equipment via RFID Tags. This tracking application has formed the basis of a Proximity Detection System or Collision Avoidance System (Schiffbauer and Mowrey, 2001; Kent, Fischer and Schiffbauer, 2011) thereby improving safety and increasing control in the mining environment. This paper discusses the growth of digital technology as the backbone for communications in underground mining applications. This growth has allowed the ‘convergence of technologies’ (occurring in the general business world) to be available to mine operators in general and underground mine operators in particular. Mine Site Technologies’ involvement with major mining companies and mining equipment manufacturers (OEMs) in developing and supplying their communication systems is also discussed.The latest technical requirements and specifications for communication systems for underground and open cut mines will be reviewed.

Nov 22, 2011

By K Cochrane

Time and time again history shows us that mine closures are sustainability failures. Mine operators do not know how to turn the mine closure into an asset and communities around the mine do not know how to plan or what to implement to be sustainable when the mine needs to close. If we want to achieve sustainability when we close a mine, we generally need to consider what economic activity we will have to create leading up to the mine closure to ensure that the communities remaining in the area are not worse off after mining than before. There is not one silver bullet solution to mine closure, as all mines are affected by different environmental and socio-economic conditions. That is one of the reasons why mine closure is so difficult.Effective stakeholder engagement is the nucleus around which sustainability is built. Achieving sustainability as part of mine closure means not only a self-sufficient community, but also could lead to transformation of that asset.A key issue is that neighbouring communities become completely reliant on the mine. The mine has influenced the economic, environmental and social aspects of the community and with no alternative economic sources. The community and municipality will struggle with capacity to maintain infrastructure, services and jobs. This not only impacts the mine workers and their families but also other businesses and people in the town that make a living by servicing the needs of the workers and their families. Social problems associated with a mining operations and closures need to be considered. The misuse of alcohol, domestic violence, breakdown in law and order, economic and health issues all have a severe influence. Families often need to relocate from the mining town to find work. This further perpetuates the impact of the mine closure to the economic viability of the town. CITATION:Cochrane, K, 2018. Is your mine closure a sustainability failure? Transform your asset and create a self supporting neighbouring community. It’s as easy as ABCD!, in Proceedings Life-of-Mine 2018, pp 38–42 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

Newcrest Mining Limited (NML) owns and manages the Ridgeway Gold Mine (RGM) located outside Orange in the state of New South Wales. RGM is a new underground sublevel caving (SLC) operation that is ramping up production to 4 Mtpa. The success of the SLC method at RGM is strongly influenced by production drill and blast practices. Distinguishing features of the Ridgeway SLC operation include choke blasting against broken rock, drawpoint brow preservation, loading of blastholes with different in-hole bulk emulsion densities, precharging of production rings and routine drawpoint fragmentation assessment. These areas are described in the context of RGMÆs required blasting objectives, production drilling and charging activities and innovative practices.

Jan 1, 2002

The paper reviews some characteristic features of feasibility studies and discusses the need for a wide scope at the pre-feasibility stage. The performance of recent Australian gold mines against the predictions contained in their respective feasibility studies is examined, resulting in a recommendation that feasibility studies need to be improved The advantages to be gained from having a feasibility study reviewed by an independent authority are discussed, and some of the reasons for using consultants are listed. Two examples of successful optimisations in the early stages of pre-development studies are described briefly and the benefits achieved are presented. The paper concludes that feasibility studies need improvement to enhance the confidence of investors in the mining industry.

Jan 1, 1991

By S Rice, A Midlin

Many of the stacking and reclaiming machines employed in the mining industry today are operating in ways that were never envisaged in the days before they were commissioned, with greater throughput, increased annualised operating hours and load cycles well in excess of their original specification requirements being the norm. In many cases these machines were supplied prior to the widespread use of finite element modelling or, in the era when such software became commercially available, those supplied designed using simplified and/or coarser meshes than would be employed today. With many of these machines being expected to operate for many years to come, it is important that their ongoing reliability be maintained and their operational limits understood. In this paper, a case study is used to outline the method required for estimating the fatigue life already consumed and the likely real life left in a machine. By reference to the machineÆs prior operating history, the use of strain gauges in the field and the development of finely meshed finite element analysis (FEA), a coherent picture of the machineÆs operational state can be generated and then investment/maintenance decisions made to ensure continuity of machine operation.

Jan 1, 2007

By A Woodley, A N. Danoucaras

In 2012 the Bureau of Meteorology, under the banner of the Water Accounting Standards Board, released the Australian Water Accounting Standard 1 (AWAS 1). This standard has been in development since 2007 with key milestones being the release of the Preliminary Australian Water Accounting Standard in 2009 and the exposure draft of the Australian Water Accounting Standard in 2010. Throughout this period, the Minerals Council of AustraliaÆs Water Accounting Framework has developed concurrently with the Australian standards and the standards have informed elements of the framework. However, the framework is not identical to the standard as the objectives between the two are different. The objective of the Water Accounting Framework is to create consistency in water reporting of the minerals industry and to assist companies reporting to corporate sustainability initiatives. The objective of AWAS 1 is to provide information to water management bodies to facilitate decisions about the allocation of water resources. Companies are to report on an annual basis - not only physical flows of water but contractual requirements to supply and obtain water - regardless of whether the transaction has been fulfilled in the reporting period. In contrast, the Water Accounting Framework only reports on flows that have physically happened. The paper will provide summary information on aspects of AWAS 1 that are most relevant to the minerals industry, show the alignment and differences between AWAS 1 and the Water Accounting Framework and explain how to obtain the information for the AWAS 1 reporting statements.CITATION:Danoucaras, A N and Woodley, A, 2013. Alignment and differences between the Australian Water Accounting Standard and the Water Accounting Framework for the minerals industry, in Proceedings Water in Mining 2013 , pp 85-90 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

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 S SSdbom

A comparison was made between chemical analysis and ocular mineral/rock classification in health-based risk assessment of historical mine waste produced between 1625 and 1975. Large parts of the mine waste are heavily weathered and secondary minerals are abundant. The field was divided into several areas from where composite samples were collected. Seventy-five mine waste samples were selected for chemical analysis (As, Cd, Co, Cr, Cu, Hg, Ni, Pb, V and Zn) and ocular mineral/rock classification (silicate, mica, granite/pegmatite, carbonate, iron oxide ore, sulfide ore, distribution between chalcopyrite, sphalerite and galena and distribution between pyrite and pyrrhotite). The waste has been produced in conjunction with mining a complex sulfidic ore with increasing iron oxide content (mainly magnetite) towards the northern part of the field. Elevated concentrations were found for Cd (average 26 mg/kg dw), Cu (average 3500 mg/kg dw), Pb (average 4100 mg/kg dw) and Zn (average 11 000 mg/kg dw). Large differences between average and median values indicated that the data was not normally distributed, ie the metals occur as discrete minerals (eg chalcopyrite, galena and sphalerite). The ocular classification indicated low carbonate content, chalcopyrite dominating over sphalerite and galena in most samples and an even distribution between pyrite and pyrrhotite. Both analytical and ocular mineral/rock classification data were combined into a common matrix that was evaluated using multivariate statistics. Principal component analysis (PCA) showed, for instance, that chromium and vanadium were mostly associated with harder minerals and rocks. PCA also indicated that a similar graphical picture could be obtained for chemical data and ocular mineral/rock classification data, respectively. The comparison indicates that ocular mineral/rock classification can replace or at least reduce the numbers of chemical analysis in health- based risk assessment of historical mine waste.

Jan 1, 2008

By S Juras

The terms measured resources and proven reserves denote the highest level of estimation confidence in all of the major classification schemes. But what do they really bring to today’s project or mine with respect to production planning and expectations? Initial reserve declaration does not need measured resources, just indicated resources. Economic viability of a project is assessed on total reserves with nary a bonus for the amount of proven reserves. Production plans are based on grade and tonnage goals that may only coincidently correspond to proven reserves. So are the measured and proven categories still relevant? Historically, and almost exclusively in underground mines, companies only allowed mining in areas of proven reserves. Some companies still follow that philosophy. But many others will mine a mixture of probable and proven reserves without hesitation. Also what of the undeveloped project in a new district – what is to be made of their declared measured resources and proven reserves? Measured resources are commonly set either by some type of proximity to data scheme or a matter of ‘feel’ based on the qualified person’s experience. The parameters for reserve conversion focus on the project as a whole and then a portion becomes classified as proven reserves almost solely based on whether the resource category is measured. So should the mining industry continue to use these categories of resource and reserve classification? This paper will present arguments about making these categories once again more relevant. A more disciplined usage of these categories may re-introduce their relevancy in public disclosures of resources and reserves. As well a more consistent usage in operations may lead to increased confidence in managing production targets and costs.

Aug 22, 2011

By Field R. V, Graieg O, George T. J

The design, construction and operation ofa laboratory scale rotary pot kiln are outlined. Charges ofup to 3 kg can be heated to temperatures up to 1200°C in a controlled atmosphere. Some examples of pyrometallurgical investigations carried out using the kiln are briefly described, including thermal reactivation ofcarbon using steam at 550-850°C, high temperature testing ofkiln liners for corrosion resistance to fluoride, and calcination oflimestone. Results obtained from these trials allow either direct scale-up to the Engineering Chemistry Laboratory's pilot-scale (50-100 kg/hr) rotary kiln or modifications to be made to commercial scale processes and/or equipment.

Jan 1, 1986

CONTENTSSummaryIntroductionGeographical and Geological Outline of the RegionGrowth of the Mining IndustryTable 1: Production StatisticsGeneral GeologyRecent Alluvium and River GravelsSambeto SeriesMudstone and Basalt ContactVatukoula SeriesIntrusivesStructureGeologic HistoryLodesTable 2: Principal Lodes and Their OrebodiesMineral Assemblage and ParagenesisOre Shoots and Their ControlEmperor MineLoloma MineDolphin MineExplorationConclusionAcknowledgmentReferencesSUMMARYThe Tavua Goldfield was found in 1932 within a basin, both topographical and structural, near the sea on the north side of Viti Levu, Fiji, and has produced over £13,000,000 (Fijian) worth of gold and silver from the three mines...

Jan 1, 1953