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The Lihir deposit in Papua New Guinea (PNG) contains an estimated mineable reserve of 454t (14.6M oz) of gold in refractory sulphide ore. The Lihir Joint Venture has submitted a proposal to the PNG Government to develop an open pit mine and to install a process plant and associated infrastructure facilities on Lihir Island. The proposed process plant will employ whole-ore pressure oxidation technology, has a design capacity of 2.825Mt/a of ore containing 7.20 sulphide sulphur, and is expected to average 19.3t/a (620,000 oz/a) in gold production during its first 12 years of operation.An extensive program of process development testwork and feasibility engineering was completed to establish the process plant design for the Lihir Project. Summary results of this test-work as well as key design criteria, the process flowsheet, and major equipment selected for the commercial plant are presented and discussed.

Jan 1, 1994

By K Williams, T Donohue, W Chen, T Roessler, A Katterfeld

Wet sticky iron ore poses particular difficulties in every aspect of the material handling process. Material hang-ups in bins, pipes and chutes; carry-back and spillage due to insufficient belt cleaning; clogging of screens; malfunctioning of crushers as well as rat holing of gravity reclaimed stockpiles are all predominantly due to the inherent cohesion and adhesion characteristics of the wet, sticky ore (Roberts, 1993). Limited understanding and quantitative measures on the stickiness of such a material significantly lower the mining operation efficiency.This research aims to investigate the cohesion and adhesion characteristics of the wet, sticky ore on physical modelling, experimental techniques and numerical implementation. Initially, the suitable bridging mechanism that contributes to the cohesive and adhesive forces within the iron ore material was identified (Hering, Martin and Stohrer, 1989; Rumpf, 1958). A cohesion/adhesion energy density factor based contact model was then introduced to describe the stickiness of the material. Secondly, an experimental system was proposed to directly test the stickiness of the material. Such a system is able to obtain both the cohesive/adhesive shear force and tensile force of the material at a specific moisture content. Lastly, the implementation of the proposed cohesion/adhesion model into the discrete element modelling (DEM) software was also discussed. A cohesion/adhesion calibration for modelling wet sticky iron ore in DEM was then conducted to ensure the material modelled in the simulation is reflective of the reality.From the study, understanding of the cohesion/adhesion characteristics of the wet iron ore material is significantly enhanced. Experimental and numerical outcomes can be directly applied for better designing or optimising the material handling processes that involve wet sticky iron ore. Consequently, the mining operating costs can be greatly reduced.CITATION:Chen, W, Donohue, T, Williams, K, Katterfeld, A and Roessler, T, 2015. Modelling cohesion and adhesion of wet, sticky iron ores in discrete element modelling for material handling processes, in Proceedings Iron Ore 2015, pp 387–392 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By J Arola, B Kettunen, W M. Bond

Separation of fine and coarse particles as separate streams prior to flotation, and their differential treatments, could substantially increase recovery and reduce collector consumption. A series of simulations was carried out to quantify the benefits from plant scale implementation of such a treatment at the Ispat Inland flotation circuit (Minorca mine). The study involved detailed plant sampling and sample analysis to generate the data needed for simulation studies. Samples were taken from all the streams from flotation feed to final concentrate, as well as cell lips and cell pulp. Sampling was repeated for the second ore blend that was processed by the plant during different periods of a year. Sample analysis involved sieve analysis and size by size chemical analysis for total iron, magnetic iron and silica. Raw data were mass balanced, and flow rates within the circuit were calculated. Mass balanced data were used to calculate model parameters representing the existing conditions. Usim Pac was used for both mass balancing and simulation studies. Available pilot and bench scale data were utilised to define the modified flow sheet and expected performance. The simulated flow sheet included classification of flotation circuit feed by hydrocyclones. While the coarse fraction followed the existing flow sheet, the fine fraction was sent to a magnetic separator. Magnetic and rougher flotation concentrates were combined to form the final concentrate. Two simulations for each blend were carried out. The first one assumed that there would be no change in size by size kinetic behaviours of both gangue and magnetite due to this modification. This was named as the worst case scenario, in which particles had a longer residence time due to reduced flow rates within the flotation cells. The second scenario anticipated that there would be an increase in recoveries of gangue and magnetite going into froth launder due to more efficient use of collector in absence of fines. Results showed that pre-classification of flotation feed could improve the flotation recovery by 0.3 - 0.5 per cent, with the major benefit being significant reduction (40 - 60 per cent) in the amount of collector used.

Jan 1, 2005

By C Rule

In 2003, Anglo Platinum, in a joint development with Xstrata Technology, installed the world’s first 10 000 litre IsaMillTM in a concentrate regrind duty at the Western Limb Tailings Re-treatment Plant. The success of that installation was the enabling event for Anglo Platinum to proceed with a substantial investment in horizontal stirred milling technology. Since 2006 an additional three IsaMillsTM in concentrate regrind duties and a further 18 IsaMillsTM in the more technically challenging coarse grinding mainstream applications, have been commissioned in group Concentrator operations - bringing the total number of IsaMillsTM installed in Anglo Platinum plants to 22.A collaborative approach between Anglo Platinum and Xstrata Technology towards improving milling efficiency and reducing operating costs, through internal mill component wear optimization and operating recipe development, has resulted in further improvements in the overall success of IsaMillsTM in the flow sheets of many Anglo Platinum operations. The addition of IsaMillsTM in the Anglo Platinum flow sheets has improved plant PGM recoveries by as much as 5%.This paper explores the improvements made to the IsaMillsTM flow sheet and mill internal design and shares some of the operating experience with IsaMillsTM technology in Anglo Platinum

Aug 8, 2011

This paper outlines the thermodynamic and mass balance principles which affect the distribution of cobalt between matte and slag during the pyrometallurgical treatment of nickel - copper sulphides and considers the implications with regard to maximising the recovery of cobalt from the smelting and converting circuit.

Jan 1, 1992

By S J. Clarke, G Sieders

Double corrosion protection (DCP) rock bolts have evolved to become complicated assemblies comprising numerous components. This complexity is mainly associated with durability considerations including potential exposure to adverse groundwater conditions and ensuring separation of dissimilar metals within the bolt assembly itself.Recent progress in the construction of glass-fibre reinforced polymer (GRP) rock bolts have the potential to provide a viable alternative to conventional steel rock bolts in civil tunnelling applications. The durability of the material results in a much simpler bolt detail and permits the use of resin rather than solely cement based grouts.This paper presents the findings of the comparative structural testing of GRP bolts with conventional DCP steel bolts. The axial load performance, including stiffness, ultimate capacity and ductility of bolts are compared. Shear behaviour of bolts is considered, including durability issues associated with damage to the plastic sleeve used in DCP bolts.The paper also considers other issues which are relevant to the design of temporary and permanent rock bolts used in tunnel support, such as initial tensioning and grouting. Long-term performance, including durability and creep are also reviewed.CITATION:Clarke, S J and Sieders, G, 2014. Comparison of glass-fibre reinforced polymer rock bolts with double corrosion protection steel rock bolts for use in tunnel applications, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 237–246 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By R F. Cota, C Freeman, A Heberle

"The Lamego mine is an underground gold mine in the Iron Ore Quadrangle in Minas Gerais state, Brazil. The mine produces 48 to 50 koz per annum, as part of the larger Cuiabá-Lamego Complex. This combined unit is AngloGold Ashanti’s largest gold producer in the Americas, contributing with 310 to 320 koz per annum.The mine started production in 2009, utilising cut-and-fill mining methods.A mining method change was trialled in 2014, introducing open stope methods. The key benefits proposed from this change are considered to be: improved safety by eliminating re-entry mining methods reduced mining costs/increased productivity from utilising bulk-mining operations.The results from the trial were encouraging, and open stoping participation expanded beyond a trial.Production from open stope areas reached 180 000 t (40 per cent of total run-of-mine; ROM) in 2015. While the change in mining method resulted in higher production rates, it also introduced a critical issue in terms of stope recovery rate.Average underbreak (unplanned loss of ore) in the larger open stopes reached 21 per cent in 2015. To manage this ore loss, a project targeting higher recovery was structured with three primary components: analyse current performance to define contributing factors (design process gaps, operating practices) investigate corrective actions apply corrective actions and maximise team engagement to ensure changes become standard practice.Within six months of commencement, a range of contributing factors had been identified, and the majority of the associated corrective actions implemented, including increased team engagement to ensure changes were not ‘once off’ actions.The outcomes show a clear reduction in underbreak (average ~12 per cent for 2016), with further improvement opportunities identified. The challenging target is now to achieve a further reduction to 10 per cent underbreak as the average for 2017. The results contributed 1400 oz and additional US$ 0.5 million to the cash generation profile for 2016.CITATION:Heberle, A, Freeman, C and Cota, R F, 2017. Increasing stope recovery in an underground gold mine by using effective analysis, corrective action and employee engagement processes, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 117–122 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 16, 2017

By D Phillpotts, S M. Mantsho, P Strobos

A challenge on many industrial flotation circuits is controlling concentrate mineral grades using measurements that are provided infrequently. The mineral grades in concentrate streams are a critical performance indicator in any industrial flotation circuit. Failure to achieve concentrate mineral grade targets has significant financial consequences on a flotation operation. A violation of a gangue mineral grade limits by the concentrator may also result in significant penalties. Online grade analysers which can provide reliable real-time grade measurements are essential for effective grade optimisation. The Blue Cube MQi analyser (by Blue Cube Systems) has recently come to prominence for its ability to rapidly determine mineral concentrate grades online and in-stream. This has provided excellent insight into the actual process dynamics in the flotation circuit, and hence enabled real-time control and optimisation of concentrate mineral grades. MintekÆs Measurement and Control division, specialising in advanced control solutions for mineral and metallurgical industries, has had the opportunity to link the FloatStar Grade-Recovery Optimiser to the measurements provided by the Blue Cube system at a nickel concentrator plant. The project initially focused on stabilising the final concentrate grade without directly accounting for nickel recovery. The site later procured additional Blue Cube MQi analysers, resulting in the expansion of the FloatStar Grade-Recovery Optimiser to incorporate recovery component in the performance. This site already had the FloatStar Grade-Recovery Optimiser for several years, but the original grade measurement device was unreliable and ultimately failed. The system was reactivated once the Blue Cube system was installed, replacing the old analyser.CITATION:Mantsho, S M, Phillpotts, D and Strobos, P, 2012. The implementation of FloatStar grade-recovery optimisation control solutions using Blue Cube online grade analysers on industrial flotation circuits, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 363-368 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By D Maconochie, S Pradhan, M Reed

The Waterview Connection will provide a high-quality strategic alternative to State Highway One and complete Auckland’s Western Ring Route connecting State Highways 20 and 16. The project includes twin three-lane motorway tunnels 2.4 km long and 13.1 m internal diameter (ID). The tunnel construction started in November 2013 using the tenth largest earth pressure balance (EPB) tunnel boring machine (TBM) in the world. The tunnels will pass beneath urban and greenfield areas as well as a major local arterial road. The project is being delivered by an alliance of constructors, designers and the New Zealand Transport Agency. This paper describes some of the key innovative and cost saving design solutions that have been achieved through collaboration in the alliance environment with the construction team, owner’s verifier, the segmental lining precast suballiance and the M&E suballiance for the underground works. The key design elements of the tunnel comprise a three-lane roadway, invert culvert and backfill, precast segmental lining, sixteen mined cross passages including a low point sump cross passage and steel segments for opening to the cross passages. This paper reviews interdisciplinary design integration and the economies achieved in the permanent works tunnel lining design, including reduction in lining thickness and optimising reinforcement, cross passage separation of 150 m, efficient design of the invert culvert and backfill design, main drainage pipe and low point sump. The paper also describes the attributes of the TBM and the invert culvert construction methodology.CITATION:Pradhan, S, Maconochie, D and Reed, M, 2014. Tunnel design in an alliance for Waterview Connection, New Zealand, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 425–430 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By A Cranley, A Giblett, S Thacker

The Newmont Tanami Operations are located in the Northern Territory, approximately 550 km north-west of Alice Springs. The Granites process plant commenced operations in 1986 as a 300?000 t/a ball mill / carbon-in-leach (CIL) plant and has undergone numerous expansions between that time and the current day, with project-to-date gold production exceeding 6.5 Moz. Annual plant throughput has exceeded 2.8 Mt/a while processing a blend of open pit material and ore from the Callie Deeps underground mine, with annual gold production exceeding 400 koz. In 2013 the operation processed 1.8 Mt of underground ore for the production of 323 koz of gold.This paper reviews the operation and expansion of The Granites process plant since the mid to late 1980s with particular focus on the gravity gold recovery circuit. The Tanami ores contain significant levels of free gold, and gravity recovery has long been an integral component of the metal recovery process at the Granites plant. The results of ten years of gravity circuit performance analysis and optimisation are presented.CITATION:Giblett, A, Cranley, A and Thacker, S, 2014. Three decades of gold production at the Newmont Tanami operations, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 209–216 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By B Murphy, J L. Heath

Installation of flotation equipment is a lengthy and intricate process involving conceptual design, detailed design and layout, equipment installation, equipment commissioning and handover prior to the plant commencing operation. During these steps, mistakes are often made that lead to increased costs and/or schedule delays in bringing the new equipment online.This paper presents a series of recommendations for the installation and commissioning of flotation equipment to minimise mistakes and ensure that plant production commences efficiently with a minimum of resources. The advice herein is based on lessons learnt from recent flotation equipment commissioning. It is intended as resource material for flotation plant designers, construction contractors, metallurgists and operators, and is applicable to both new and existing plants.CITATION:Heath, J L, Murphy, B and Bourke, P, 2014. Effectively installing and commissioning flotation equipment, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 399–404 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By S Mitchell

Jetcrete Australia Pty Ltd, shotcrete contractor took the initiative in 2008 to discontinue the use of ‘road registerable’ concrete trucks for all underground works in Australia and internationally.The rationale for this decision was basic, safety. Historically these vehicles have been and still are involved in far too many accidents; this obvious trend needs to be addressed by engineering out the root cause of the problem which in this case is suitability for purpose.Road registerable concrete trucks have been widely used for the delivery of concrete in Australian mines for many years prior to and after the inception of wet shotcrete as ‘in cycle’ ground support in underground excavations around 1992. With this inception came a wide interest in the shotcrete process and an influx of new shotcrete contractors, all using road registerable concrete trucks to deliver the large volumes of Shotcrete required for these services and in turn largely increasing the use of these vehicles underground. The road registerable concrete trucks were difficult to control and each trip underground required the operators to maintain good management of the inherent risks. We virtually had no reasonable alternative for the industry and could only encourage the operators to drive with soft controls such as, reducing overall speed to a maximum of 15 km per hour when declining, regardless of the road conditions, coming to a complete halt prior to turning into any sharp corners, remaining in the same gear both inclining and declining.

Mar 21, 2011

By M Byrne, P Newman, M Lindqvist

SomincorÆs Neves Corvo Mine, one of the largest copper producers in Europe, is currently constructing a paste backfill plant in order to replace cemented rockfill in its bench and fill stopes and possibly replace hydraulic sandfill in the drift and fill stopes. A 250 m flow loop was constructed at the mine and the flow properties of various paste blends were investigated. Cycloned tailings and total tailings were both pumped successfully as pastes and were also combined with waste rock for additional testing. The pressure losses in 102 mm and 154 mm diameter pipeline were recorded at flowrates up to 60 m3/hr and are presented at slumps from 120 mm to 250 mm. The data showed the sensitivity of paste mixtures to slight changes in consistency, confirming the need for accurate control during paste production and distribution. The flow results clearly showed the different paste behaviour between cycloned and total tailings pastes and the change in properties at low and high slumps. In addition to pressure loss data, strength testing was done on 38 mm and 82 mm diameter samples. Further strength testing is ongoing at the mine using fly ash as a supplement to cement, reducing the overall binder cost. Preliminary engineering for the underground distribution system is briefly discussed, with reference to the siting of the plant. The Neves Corvo Mine is particularly shallow and alternative methods to pumping were sought in order to ensure sufficient hydraulic head for underground distribution. The comparison of options had to take into account the capital and operating costs, the operation of the plant and the impact on the future expansion of paste fill utilisation at Neves Corvo.

Jan 1, 1998

By H Kundapen, B R. Bolton, H Davies

The Ok Tedi porphyry copper-gold mine is located in the Star Mountains of Western Province, Papua New Guinea. Open-cut mine commenced in 1984 and is due to cease around 2010. The mine produces a total of 88 Mt of waste annually including 58 Mt overburden and 30 Mt tailings, which are discharged directly in to the Ok Tedi River. Mine derived wastes are transported downstream and deposited within the river channel in a variety of bar forms. The prevailing hydrogeological conditions including, velocity, competency, capacity, gradient, grain size and specific gravity, control the deposition and segregation of these sediments. Periodic exposure of the reactive sulfides to oxygen during fluctuations in the river discharge may result in oxidation, localised acid generation and liberation of metals into solution. To evaluate the significance of this issue, Ok Tedi Mining Limited initiated an investigation of the sediments deposited in the upper Ok Tedi River as part of its overall ARD Management Program. The specific objectives were to: evaluate the acid-forming characteristics of identified high sulfide river deposited sediments; characterise geochemically the waters in contact with sulfide-bearing river deposited sediments; map and monitor exposure areas and oxidation depth of deposited potentially acid forming (PAF) sediments; determine the depositional processes controlling sulfide distribution; and assess lag period, oxidation and metal release rates for the sediments. This work included the analysis of sediment and water samples collected on a 50 + 50 metre grid at six gravel/sand bars. The sediment samples were analysed for total sulfur, ANC, NAG, total sulfur and total copper. Water samples were tested for general water quality parameters, sulfate and a suite of dissolved metals including; Al, Ca, Cd, Cu, Fe-sol, K, Mg, Mn, Na, S and Zn. This paper presents the results of these investigations with particular emphasis on the geochemistry of the river sediments and associated contact waters.

Jan 1, 2003

By Roberts AW

Bulk materials handling operations depend on efficient storage and gravity flow facilit- ies. ,It is important that proper attention be given to the complete storage bin or stockpile and feeder combination. The paper briefly des- cribes the principles of efficient feeding and discusses the common types of feeders under practice. While ideally unaided gravity flow should be sought, occasions arise where flow promotion is necessary. Various types of flow promotion devices are described and their operational features evaluated.

Jan 1, 1978

By Enever JR

In-situ rock stress measurements conducted in the Phillipines and on Bougainville have revealed stress fields significantly different from expectations based on intraplate experience. The results have potential significance in regard to both engineering practice in the Pacific Rim region as well as in helping to understand the geological processes occuring near subduction Zones.

Jan 1, 1987

By G Harbort, D Zoetbrood

"The Phu Kham copper-gold operation in the Laos People’s Democratic Republic (PDR) is owned and operated by Phu Bia Mining Limited. PanAust Limited holds a 90 per cent interest in Phu Bia Mining Limited, with the remaining ten per cent held by the Laos PDR Government.The original 12 Mt/a copper-gold concentrator at Phu Kham commenced production in April 2008. An incremental improvement program resulted in a number of circuit changes being incorporated by 2011, including conversion of conditioning tanks to flotation cells and the installation of a Jameson Cell cleaner scalper. In 2012 the Phu Kham Upgrade Project was commissioned to increase throughput to 18 Mt/a. In April, 2013 the Phu Kham Increased Recovery Project was commissioned to maximise performance by debottlenecking the plant IsaMill™ regrind and cleaning capacity.With the variable mineralogy of Phu Kham ore, control of the c concentrate regrind circuit is essential in terms of achieving effective liberation to maintain concentrator performance. On a routine basis laboratory regrind signature plot data is compared with daily surveys of the operational IsaMills™. More extensive surveys are also conducted to determine size distribution on a mineralogical basis and the effect of fine regrinding on pulp electrochemistry and flotation performance. This paper provides a review of the operating performance of the Phu Kham IsaMills™ with regard to power draw, feed and product size distribution, feed per cent solids, mineralogy and pulp electrochemistry. Operating performance is compared with the IsaMill™ signature plot test for predicting performance.Citation:Harbort, G, Zoetbrood, D and McNab, B, 2016. Operating Performance of the Phu Kham IsaMill™, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 39–50 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By D Horacek, I K. Sheppard

Ok Tedi is in a period of transition. By 2008 mill feed will consist of higher levels of high-grade but metallurgically challenging skarn ores. Additionally, the Taranaki pit will start production in 2008 along with the start-up of a new pyrite concentrator. Taranaki ores are very high in sulfur. Sulfur is captured in a pyrite concentrate prior to tailing entering the Ok Tedi River. These and other complex scheduling issues will need to be resolved over a critical three-year period. With these requirements in mind, Ok Tedi contracted AMC Consultants to develop a custom version of the Life of Business Optimisation System (LOBOS¬) to assist medium-term production scheduling at Ok Tedi. LOBOS utilities enable Ok Tedi planning engineers to:import polygon-based reserve data (Blast Masters) from MineSightÆs Interactive Planning Tools (IP Tools); graphically construct block sequencing and material flow constraints; edit constraints defining standard scheduling, processing and financial relationships; define dump and stockpile attributes; and assign capacities to production systems, plants, dumps and stockpiles. LOBOS converts Ok TediÆs production scenario into a mixed integer program (MIP) and submits the resulting model to IlogÆs Cplex MIP Solver. The Solver seeks an optimal production schedule that maximises net revenue per mill hour while meeting all constraints. This paper introduces Ok Tedi and its production requirements and relates these requirements to the facilities developed for an Ok Tedi version of LOBOS.

Jan 1, 2007

By W Wu

The prospect of discrete element modelling (DEM) being used as an everyday design tool for transfer chutes in the iron ore mining industry is becoming more and more probable. However, much care needs to be taken to ensure accurate results are obtained. Whilst there are many publications in industry portraying the potential of DEM, there is little evidence of where it has been validated against a real set of experimental results. The purpose of this investigation was to gauge whether the incorporation of the physical properties of a specific bulk material at the DEM pre-processing stage can yield visually and numerically accurate simulations for a simple flow case. Effects such as irregular particle shapes, varying frictional properties and coefficients of restitution, all found through experimentation were investigated. Video analysis was used to compare simulations to real flow cases. It was found the most critical attributes in determining the accuracy of the simulations were particle shape and wall friction. Keeping the particle-to-wall friction factor constant was not sufficient to describe the flow accurately. But by introducing the varying effects of wall friction with consolidation stress, the correct results were simulated.

Jan 1, 2007

By R Bourcier, T Rafferty

Following an underground coal mine explosion, it is important that ventilation is quickly restored to ventilate the mine and affect a mine rescue. To achieve this, surface ventilation fans must be suitably protected from explosion damage, but still able to be quickly restored.A review of all Australian coal mine regulations was carried out, revealing that Australia has no prescriptive regulations that specify the design of explosion relief panels and the protection of ventilation fans in the event of an underground explosion.To better define the level of protection required, this paper reviews and extracts details from relevant major international regulations and standards on the subject.A suitable design methodology for the protection of ventilation fans is presented that could be applied in Australia, using a combination of explosion relief panels, appropriate isolation of the fan, and ventilation shaft/mine design.CITATION:Rafferty, T and Bourcier, R, 2013. The protection of surface ventilation fan installations from underground explosions, in Proceedings The Australian Mine Ventilation Conference , pp 169-173 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013