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By J Harding, S Munro, R A. Bearman

Despite the importance of the primary crushing stage, performance optimisation is not well analysed with sufficient focus to give improvement opportunities. At the Newcrest owned Telfer operation, liner life plays an important part in scheduling planned maintenance. Major consideration is given to monitoring crusher performance, as the highly abrasive nature of the feed significantly impacts the liner wear life. A study was undertaken by the lead author which focused on establishing a strong baseline of accurate data pertaining to the performance of the crusher, in terms of, operating parameters, liner life and key machine design factors. As part of the study, mining feed materials were examined for a particular set of liners and this revealed that improved methods should be pursued. Due to the competitive nature of the mining industry, the business solution to complex problems with long shutdown cycles should be streamlined to incorporate a non-operational modelling approach that is significantly more efficient than traditional online trial and error methods. In order to dramatically reduce the time and business risks, it was decided to engage services to model and simulate the liner life by varying main operational and mechanical factors. The key to all simulation work is gathering high quality baseline data. Such data allowed deployment of the Kinematic Crusher Model and validation of the model against worn 2D wear liner profiles. The proven model was then successfully deployed to predict operational values that defined crusher performance. To enhance the study, further investigation into a set of mechanical and operational simulations generated a sensitivity matrix measuring key performance parameters throughout the wear life of the liners. The study revealed throughput as a highly sensitive parameter and a change in eccentric throw provided the greatest improvement in extending liner wear life.

Aug 24, 2022

By N Eriksson

BolidenÆs Aitik mine, located 100 km north of the Arctic Circle in northern Sweden, is one of EuropeÆs largest copper mines. This operation produces 18 Mt of ore per year and 99 per cent of this tonnage needs to be deposited as tailings. The tailings pond currently covers 1140 ha but at closure it will hold around 760 Mt of tailings and occupy an area of 1400 ha. The tailings contain less than one per cent sulfur and only 0.03 per cent copper. The carbonate content is as low as 0.25 per cent but silicates, with substantial accumulated buffering and metal adsorption capacity, are abundant. A programme of comprehensive material characterisation and investigations has been undertaken in order to design a decommissioning strategy that meets the regulatory requirements and secures long-term physical and chemical stability of the deposited tailings. The main concern has been the potential generation of acid rock drainage (ARD). Standard tests using acid base accounting (ABA) and humidity cell tests during 15 weeks were not conclusive regarding the ARD generation potential. The accuracy of the results was considered to be unsatisfactory, therefore the humidity cell tests were gradually extended in time. In total, almost four years of humidity cell tests were conducted on various sets of samples which were selected in order to cover the variation in sulfide content existing on site and in various points of the milling process. The laboratory results were subject to detailed geochemical evaluation in order to fully understand the interaction between acid-producing reactions, driven by weathering of sulfides, and acid-consuming reactions by dissolution of carbonates and alumino-silicates. The laboratory tests were followed by both pilot tests and field measurements in order to estimate the scale dependency between the laboratory and the field results. It was found that sulfide weathering rates in the field were considerably lower than those measured in the laboratory. However, it could not be verified that the tailings top layer would maintain a neutral pH in the long term even under field conditions. Thus, a reviewed tailings management plan, including de-pyritisation of the tailings during the last years of operation, is considered.

Jan 1, 2003

By P Ottenio, B CarrT

In the last 40 years, the froth flotation process widely spread in the paper industry becoming the dominant technology for ink removal from recovered paper slurries and cellulose fibres recovery. Most of current models used to describe the flotation deinking process are based on hydrodynamic and statistical theories of ink particles collision/attachment to air bubbles. The complexity of these theoretical models, together with the variability of the recovered papers composition, does not allow to define a set of æeasy to handleÆ equations to be used for modelling industrial flotation cells. This main limiting aspect makes that, in several deinking process modelling tools, basic parameters used to characterise the flotation unit, ie yield, ink removal efficiency, water loss, are constant parameters. Although in some process simulation tools the flotation yield/efficiency is adapted to process control parameters (air ratio, pulp flow, pulp consistency), physicochemical variables (namely the pulp frothing aptitude, the pulp surface tension and the ink adhesion energy to air bubbles) are not taken into account to adjust the flotation yield/efficiency. Data collected during recent laboratory and pilot plant experiments focusing on the role of surface active substances on the flotation efficiency were therefore interpreted and used to identify general trends that could be described with simple semi-empirical models. A set of model equations using surface tension and froth removal height as main variables was then defined in order to describe the behaviour of a pilot flotation cell. Trends obtained during the dynamic simulation of the deinking pilot plant were in good agreement with experimental data obtained under similar experimental conditions, thus indicating that developed equations can forecast with good approximation the behaviour of a flotation deinking unit.

Jan 1, 2005

By D Bertoldi, C Haines

"The Waihi Gold Mine (WGM) operated by OceanaGold New Zealand Limited is a wholly owned subsidiary of the OceanaGold Corporation of Australia. Traditionally WGM has stockpiled and processed separate campaigns of open pit and underground ore. The ore is processed via a conventional semi-autonomous grinding (SAG) / ball circuit (SABC). The low aspect SAG mill operates in a closed circuit with two 20" cyclones, whilst the ball mill is also a closed circuit with a 10" cyclone cluster. A major wall movement in April 2015 ceased open pit operations indefinitely, 18 months ahead of the mining plan. This immediately reduced the forecast mill tonnage leaving two options: begin campaign milling or change the operating strategy and target lower throughput. Additional cost pressures necessitated improved milling cost efficiency. The immediate ore restriction limited processing alternatives to within the existing major infrastructure. Available comminution circuit survey data laid the foundation for developing a comminution model using the JKSimMet™ software package (version 6, created by KJTech). A number of flow sheet variants were then evaluated based on predicted throughput and efficiency. The comminution models suggested opportunities for improved efficiency lay in reducing throughput and increasing utilisation rather than on/off campaign milling under the existing operating philosophy. A series of process alterations followed, delivering new cost efficiencies that maintained the current $/t processing cost. This paper aims to review the change in circuit performance and examine the decisions and challenges faced following the transition from a high tonnage SABC circuit to lower tonnage SABC circuit.Citation:Haines, C and Bertoldi, D, 2016. The Transition from Semi-autogenous to Autogenous Milling at Waihi Gold, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 303–312 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By G Morgan, C Kemp

In December 2010, a trial of borehole radar technology was conducted to test the usefulness of the technique in better refining the position and geometry of narrow vein orebodies away from the primary data sources of drilling and mapping of development excavations. This paper summarises the reasons why the technique was applied, describes the testing methods selected and summarises the outcomes of the trial.Poor reconciliations of recovered metal from a section of an orebody at Jundee mine site, Western Australia, led to an investigation that identified insufficient understanding of the geometry of a narrow vein orebody as a potential cause. This orebody was situated between mapped development excavations and away from surrounding drill holes. Borehole radar was identified as a possible technique that could supply information on vein location and continuity away from other data sources allowing more accurate orebody modelling and subsequent stope optimisation.A borehole radar instrument (10 - 100 MHz frequency) was inserted into pairs of purpose-drilled boreholes on either side of relatively well-constrained mineralisation and the radar reflection data was collected. This process was repeated in five locations across the mine to represent the most common geological settings, lithologies and orebody varieties encountered at Jundee to determine the suitability of applying the technique in each of these settings. Collected, processed and interpreted radar data was compared to other geology data collected independently for verification and interpretation.Conclusions drawn from the analysis were that the technique could effectively determine the following features of the mineralised veins in the majority of test environments: geometry of veins, magnitude of offsets where structures intersect and orientations of planar structures with short strike length. The technique was very useful in selecting the appropriate structural interpretation where available data could lead to multiple, equally likely, interpretations.CITATION:Kemp, C and Morgan, G, 2012. Using borehole radar to refine orebody interpretations in a narrow vein gold deposit, in Proceedings Narrow Vein Mining 2012 , pp 121-130 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 26, 2012

By H Wright

Black Rock Cave (BRC) is a sublevel cave which was developed in 2018–2020 and has been in production since November 2020. BRC is part of the Mount Isa Mines complex and extracts a leached orebody comprising of high-grade chalcocite ore, situated below the historic Black Rock Open Cut workings. The mine is owned by Mount Isa Mines and operated under contract with PYBAR Mining Services. In 2021 a number of rockfalls occurred throughout the mine and were increasing in frequency. This culminated in a major rockfall on the decline in June 2021, after which the decision was made to withdraw all persons from the mine, initiate rehabilitation and conduct further investigations to deduce a safe method to provide long-term support. The rockfall investigations have shown that the corrosive nature of the highly leached rock mass can consume a split set in less than 18 months. A review of potential corrosion resistant ground support methods concluded that steel split sets have a safe lifespan of six months at BRC, and that all workings must have corrosion resistant support installed prior to exceeding the safe life of the friction bolts. The review recommended the use of 4 m cable bolts as the most suitable method of corrosion resistant support. This new support system, and the requirement to rehabilitate all mine workings within the leached orebody, had an impact to the schedule and an effect on both equipment and manning levels at BRC. Accelerated jumbo rehab allowed access to the production levels within two months of the rockfall. Cable bolting then followed the jumbo bolting in all leached areas. The direct impact has been ten months of reduced production, due to night shift closures of the decline to enable cable bolting. The impact to the mine has been minimised by the small flexible team that enabled the mine plan to change rapidly and often to accommodate the challenging conditions. In less than two months from the rockfall event, production had resumed. Within ten months of concluding that the mine required; full rehabilitation, a new support system and a full re-schedule, normal mining operations had restarted, with pre-event productions rates being achieved.

Mar 29, 2023

By R P. Varden

This paper looks at the design of the Bentayga raisebore with subsequent back analysis using a LiDAR survey. A search for LiDAR raisebore assessment publications shows little work has been done on this subject. The paper examines the empirical design and RS2 modelling assessment with the bored condition. The high resolution of the LiDAR enabled mapping of weak structures that were located on the geotechnical investigation hole the orientations of which could not be determined. In addition, the scan showed were water ingress was occurring, potential stress overbreak and structural controls on stability. The LiDAR results were able to confirm no additional support work such as a shotcrete liner is necessary. The LiDAR results have been analysed in one metre increments as volume of overbreak against the empirical stability criteria (McCracken & Stacey 1989). The future use of LiDAR mapping over a range of rock mass conditions will provide quantification of the established empirical assessment improving its reliability. It is also a useful and accurate tool to monitor long term stability of a raisebore due to stress change or ore pass due to wear.

Mar 15, 2021

By C Delwig

ThyssenKrupp specialises in the manufacture of high-grade steel-sheet products. Its main customers include the automotive, construction, household appliance, energy and packaging industries.At its works in Duisburg, Germany, ThyssenKrupp Steel Europe produces 12 Mt of crude steel annually, making Duisburg one of the world’s largest steel hubs.ThyssenKrupp have installed an online elemental analyser and limestone dosing control System on one of three Sinter strands at Duisburg in an attempt to control the sinter raw mix with better precision. Traditionally, set point changes to the raw mixture were made after sampling and laboratory analysis of the sinter product. The analyser chosen uses prompt gamma neutron activation analysis to determine the elemental content of moving material on a conveyor each minute and was supplied by Thermo Fisher Scientific. The project goal was to control the CaO/SiO2 ratio (basicity) and reduce its variability in the sinter feed.Evaluation of the system has shown that the addition of the online analyser reduces the time lag related to the former method, therefore upset conditions can be reacted more quickly by the control system, and this has resulted in a more stable sintering process. As a result, the sinter feed variability in case of the basicity has been reduced by half. While CaO/SiO2 control was the initial aim of the project, a number of other benefi ts have been realised, such as a reduction in return fi nes and a financial benefi t of 0.11 €/ton of sinter attributed to the reduction of coke breeze and limestone. ThyssenKrupp Steel Europe has identifi ed that additional information available from the analyser could be used to optimise the complete sinter process.The project was carried out with a financial grant of the research program of the ‘Research Fund for Coal and Steel’.

Jul 11, 2011

By P Breuer, A Simons

The sulfidisation, acidification, recycle and thickening (SART) process is currently being used at NewcrestÆs Telfer Gold Mine to recover cyanide and copper from the cyanidation tails of the pyrite concentrate carbon-in-leach (CIL) process. While the process has been effective at attaining high recoveries of cyanide and copper, the Telfer SART plant has experienced higher than expected sulfide additions to achieve these recoveries. This paper details the results of surveys on the Telfer SART plant, which show that residence time appears to be causing the high sulfide consumptions. The paper also details the results of laboratory scale experiments which confirm the observed residence time impact during the acidified stage of SART.CITATION:Simons, A and Breuer, P, 2013. The impact of residence time on copper recovery in Telfer Gold MineÆs cyanide recycling process, in Proceedings World Gold 2013 , pp 189-196 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By Hungerford F

Long-hole drilling technology has rapidly advanced this decade beginning with rotary drilling/pump down camera surveying and culminating in down-hole motor drilling with cableless electronic surveying over the past two years. With the latter system, a high level of directional control is achievable in boreholes up to 1000m long. Past long-hole drilling across the industry has seen a mixture of success and failure. With these experiences, new and improved techniques and equipment have evolved. A number of long-hole drilling options are available as variations on the basic rotary and down-hole motor methods. They involve different levels of cost and equipment and vary in their suitability in different geological environments and definition of targets. Long-hole drilling is mainly target applied, either in defining geological structures in greater detail, or proving important mining areas such as longwall blocks, to be free of structures. Successful drilling hinges on a combination of drilling expertise, quality and appropriateness of equipment, understanding of geological conditions and good colliery support. Drilling expertise forms part of sound interpretation through keeping relevant records, understanding the reasons for changes in drilling conditions and implementing specific tests such as coring. The final interpretation builds upon all other available geological information. There is still scope for research into improved techniques and equipment. The use of long boreholes for geophysical surveys has high potential.

Jan 1, 1988

By M Andrew, D McTiffen, M Adams

A major Ventilation Upgrade Project commenced at the Fosterville Gold Mine (FGM) in 2017 to service the ongoing ventilation requirements of the underground mining operation. The project consists of three large diameter ventilation raises totalling 1100 metres, and new axial primary ventilation fans to upgrade the mine ventilation system. With a mining depth of 1200 metres and a thermal gradient of approximately 2.7 °C per 100 metres of depth, the completion of the Ventilation Upgrade Project is key to the ongoing success at FGM. The Ventilation Upgrade Project will allow continued mining, including high-grade gold deposits, lower in the mine where heat is increasing. Figure 1 below illustrates the underground workings at FGM, and provides a general view of the ventilation upgrade works to establish the new exhaust system from the lower workings to surface. Whilst raisebore pilot drilling the H4760 Return Air Rise (RAR) from surface to 395 metres, the raisebore drill string became stuck in the raisebore pilot hole at approximately 300 metres down hole, presenting a significant technical problem and delays to the project. This Case Study provides an overview of the recovery process undertaken at FGM including the recovery of the stuck drill string. The value of the stuck in-hole equipment, the investment in the shaft site preparation, the collar stabilisation, the underground development to the base of the ventilation raise, the surface footprint prepared for the Primary Fans construction and the limited available space on the site were all motivations to recover the raisebore drill sting and ultimately recover the ventilation raise location. More importantly, the long lead-time required should a new shaft location be the final solution, and the delay this would incur to the ventilation upgrade was unacceptable. Recovery of the drill string was not possible using the capability of the Contractor’s Raise Drill. An alternative method for freeing the drill string was required. A significant amount of engagement with industry was undertaken to seek out potential solutions and draw from the experience of others. All methodologies available were considered and assessed. Ultimately, after several attempts at freeing the raisebore drill string using various methodologies, Adams Drillers and Clear Cut Interventions were engaged to provide a turnkey recovery solution.

Mar 15, 2021

By A L. Randriamanjatosoa, G Small, C Greet

In flotation simulation models, the effects of pulp chemistry other than pH are often ignored and reduced to particles hydrophobicity or contact angle, neither of which can be measured readily in real time in an operating plant. The flotation response of a given sulphide mineral is known to be influenced and can be improved by changing the chemical characteristics of the pulp during grinding and flotation. The on-line measurement of pulp pH, potential, dissolved oxygen, temperature and oxygen demand of a process stream was completed with the PCM® (Pulp Chemistry Monitor) developed by Magotteaux in this study. The data generated together with relevant plant operating parameters were used to construct an empirical model and simulate the metallurgical performance of the ore. The same approach was also applied to laboratory flotation tests data using various grinding media types. The flotation models better fit the actual data when the chemistry of the pulp is taken into account.CITATION:Randriamanjatosoa, A L, Greet, C and Small, G, 2018. Effects of pulp chemistry on plant and laboratory flotation modelling, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 423–432 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By S Jayakumari, E Ringdalen, V Canaguier

Silicomanganese (SiMn), containing approximately 16–30 per cent Si, is produced in submerged arc furnaces using various Mn sources and quartz as the primary raw materials, along with fluxes and reductants. In the high-temperature zone known as the coke bed, a silica-rich slag is formed. SiMn is produced through the reduction of SiO2 from the slag. Dissolution of quartz into slags with different compositions, the primary slag formed from the Mn sources and flux before any MnO reduction occurred, representing conditions at the top of the coke bed, and dissolution of quartz into a partially reduced slag to simulate conditions inside the coke bed has been investigated. Experimental investigations were carried out to study the dissolution of quartz particles of varying sizes, 5 mm and 25 mm in synthetic slags with different compositions at temperatures between 1400°C and 1600°C, with varying holding times. Observed results are compared with liquidus compositions and equilibrium phases for original and formed slags. Particle size has been shown to be of little importance for the dissolution. Quartz dissolved more easily in slag at top of the coke bed than slag in the coke bed. Complete dissolution was observed after 30 mins at 1600°C in all cases, but not after 0 mins.

Jun 19, 2024

By D R. Wines

The design of near-surface civil infrastructure requires detailed consideration of the geological/ geotechnical conditions, excavation geometry and sequence and ground support measures to ensure stability of the underground openings and minimal impact on overlying or adjacent infrastructure. Twin parallel road tunnels have been designed and built with connecting cross passages and a piggyback busway tunnel as part of a large infrastructure project in Australia. The tunnels were excavated in poor to fair quality rocks using road headers. Temporary ground support includes shotcrete, rock bolts and canopy tubes. Extensive numerical analyses have been performed to analyse the expected behaviour of the tunnels during excavation, including two-dimensional analyses using UDEC and three-dimensional analyses using FLAC3D. Structural defects in the rock are explicitly included in the 2D analyses to examine the potential for localised ground instability. The stress redistribution is captured by the 3D modelling with an accurate representation of the complex excavation geometry and the detailed excavation and support sequence. This paper presents the modelling methodology, numerical results and discussions on integrating both 2D and 3D analyses to achieve reasonable design.

Mar 8, 2011

By I Ametov, S Harmer, R Alford

A process that allows selective flotation separation of low Cu/S ratio minerals (chalcopyrite and pyrite) from high Cu/S ratio minerals (bornite and chalcocite) from a mixed copper mineral concentrate under controlled oxidative-reductive potential conditions has been developed. The process has been extensively tested on samples with varying mineralogy using laboratory batch flotation tests and mini pilot plant trials.In this process, the mixed final copper mineral concentrate is purged with nitrogen, and then treated with sodium dithionite to achieve a slurry Eh in the -200 to -100 mV standard hydrogen electrode (SHE) range. Flotation was then carried out using nitrogen gas. As a result, a low Cu/S ratio concentrate (<1.3) and a high Cu/S ratio (>1.6) tailing stream were produced. QEMSCAN analysis of the flotation products showed that more than 85 per cent of the chalcopyrite and 95 per cent of the pyrite reported to the froth concentrate. Chalcocite and bornite were almost evenly distributed between the concentrate and tailing streams.Surface analysis studies, focused on the mechanism of separation, showed that at a negative redox potential xanthate and possibly dixanthogen are the dominant hydrophobic species on the surface of chalcopyrite and pyrite. As a result, the flotation of these minerals remained unaffected. In contrast, a much lower concentration of xanthate species on the surface of chalcocite and bornite particles was observed. Therefore, it is likely that at low Eh the copper xanthate complex desorbs from the chalcocite and bornite surfaces, causing a decrease in surface hydrophobicity and the diminished floatability of chalcocite and bornite.CITATION:Ametov, I, Harmer, S, Grano, S and Alford, R, 2014. Selective flotation of chalcopyrite and pyrite from a mixed copper mineral concentrate under controlled redox potential conditions, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 131–140 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By D G. Rantucci

Organic carbon is a major ore contaminant at MMG’s Century mine. This carbonaceous matter is associated with shale hosted sphalerite mineralisation. It occurs as elongated lamellae and as inclusions in porous sphalerite aggregates which are fine grained and difficult to liberate from sphalerite. The carbon prefloat circuit was designed to remove the liberated organic carbon in order to mitigate excessive reagent consumption, contamination of the lead and zinc concentrates and poor flotation performance in the primary zinc circuit. The consequence of organic carbon removal is that sphalerite and galena minerals are lost to the prefloat concentrate. A Jameson Cell was installed in late 2005 as a prefloat cleaner cell. Operational experience showed that the cell became capacity limited during periods of high amounts of organic carbon in the feed and was subsequently bypassed.Reactive style operating strategies were implemented to manage the effects of insufficient organic carbon removal by the prefloat circuit but due to the relatively large circuit residence time, upstream changes meant hours before the downstream circuits were stabilised following a disturbance from excess carbon.This paper describes the modifications and testwork undertaken to enable the Jameson Cell to be operated during periods of high organic carbon in the float feed and the implementation of process control initiatives to proactively remove the required prefloat mass from the float feed to eliminate the reactive style operating strategy.The process control modifications centred on dynamically targeting a prefloat mass recovery determined by an equation relating the carbon to zinc ratio to the carbon prefloat mass as a percentage of the float feed. The equation was developed by analysing historical data. These improvements served to optimise the prefloat circuit and consequently stabilise the downstream lead and zinc circuits.

Aug 8, 2011

By B Andrew, L Krois

Ground control systems, including ground control management, play an integral role in the effective and efficient extraction of copper ore at the Xstrata Copper û Mount Isa Copper Operations (MICO). Rock mechanics engineers and support technicians at Xstrata Copper have undertaken a wide range of investigations and actions over the past few years. Outcomes from this work have resulted in the evolution of ground control management practices on the site. Specific areas of improvement include the installation of efficient one pass ground control systems, greater application of sprayed concrete for areas requiring rehabilitation and the addition of new improved products, the removal of obsolete and less efficient products used in standard ground control practice. In some areas underground, the most effective methods to manage ground control hazards continue to be a variation on proven methods that have been in use for many years in the MICO. Ground control systems for developing through the basement contact zone are very similar to that developed in the late 1980s. Similarly, ground control systems have gone through repetitive evolution, whereby some systems fall in and out of favour subject to perceived costs. For example the pouring of concrete shuttering around drawpoints in poor ground conditions has recently been re-accepted as an effective means to manage this poor environment û despite having been previously cast aside as too expensive. Ground control management systems continue to evolve towards the goal of creating a workplace that is free of rockfall-related injuries and provide for higher levels of efficient and effective techniques by which ore is extracted from the ground.

Jan 1, 2005

By T M. Brettell, D Sidea

The CSA Mine is located in Cobar, New South Wales and is operated by Glencore. Large scale underground production started from 1965, with zinc, lead, silver and copper extracted in the past. The current operations focus on copper, with a silver co-product.From 2014 to 2016, Cobar Management Pty Ltd (CMPL) undertook a major capital project to upgrade the primary ventilation system at the CSA Mine. This involved the development of ten raises using full-face raise boring from surface to a depth of 1450 m. The total length of the raises was approximately 2500 m. Geotechnical conditions were identified as a key project risk during the early planning stages of the project. Timely quantification of the geotechnical risks was required to minimise project delays and cost overruns. Geotechnical investigations were planned and conducted for each raise prior to pilot drilling and full-face back reaming.Nine of the ten raises had final wall camera and laser baseline surveys completed following full-face reaming. The surveys were conducted progressively, allowing ongoing back analysis and calibration of geotechnical evaluations as the project advanced.This paper presents the design and planning process of the raise bored excavations. It details the geotechnical investigation work undertaken to mitigate the geotechnical risks and the challenges and learnings from the project including the benefits of close collaboration between the parties involved.CITATION:Sidea, D and Brettell, T M, 2017. The CSA ventilation upgrade – geotechnical challenges and learnings, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 341–352 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017

By A Scott, S Kanchibotla, J Segui

The æMine to MillÆ concept is not new. In fact, it is the underlying objective of every mine. Unfortunately, in many operations the management structure and reporting systems have created independent æbusinessesÆ within the overall mining enterprise. This has created incentives to optimise the performance of each component of the operation rather than the enterprise as a whole. The Mine to Mill Conference organised by The AusIMM in October 1998 documented a number of case studies where run of mine ore was not presented to the mill in the best possible form for subsequent stages of comminution and processing. A number of examples were quoted where modest expenditure in the mine had a very significant impact on downstream process efficiency and hence costs. Examples included:the minimisation of fines in the mining and handling of iron ore; the management of fines in blasting and crushing for a copper heap leach operation; the control of blast damage, mining recovery and dilution in open cut coal operations; and the optimisation of mine fragmentation to increase mill throughput in gold and copper operations. The latter topic has been trialed at a number of mines and is referred to as æMine to MillÆ fragmentation. A number of æMine to MillÆ type investigations have been reported in the literature including Pease et al, Simkus and Dance, Nielsen, Scott et al, Kojovic et al, Kanchibotla et al, Bulow et al and Hawkes from the 1998 Mine to Mill Conference. In addition, a number of studies are in progress or the results have yet to be published. These studies have demonstrated the feasibility of obtaining the data required to characterise the breakage behaviour of ores and to model the impact of changes to blasting practices on process efficiency. Characterising the breakage behaviour of ores is a vital step in the management of fragmentation and comminution in mines. The characteristics of importance to fragmentation fall outside the parameters conventionally required to describe the economic geology of a deposit. æMine to MillÆ optimisation of fragmentation means that the mining engineer needs information from the geologist in order to be able to help the metallurgist. Providing this information requires close interaction between these groups.

Jan 1, 2000

Discovered in 1954 and mined since 1966, the X41 copper orebodies have produced over 143 Mt @ 3.3 per cent copper. By June 2002 the production from these orebodies had depleted the Mineral Resource to 36.6 Mt @ 2.8 per cent Cu (including 31.5 Mt @ 2.5 per cent Cu combined 2002 Ore Reserve). Mine production will ramp down to cessation beyond ten years. The 2002 Copper Business Study was commissioned to review the status of the Mount Isa copper business and to optimise the long-term strategy of the operations. The study resulted in a vastly improved geological and geostatistical model, and financial studies led to the optimisation of mine cut-off grades. Utilising these new models, a near-mine target generation workshop was conducted by the copper stream geology team. The workshop focussed on exploration for new ore sources and the extension of existing orebodies to supplement the Mineral Resource inventory for future conversion to Ore Reserves. Several prospective targets were identified and the Conceptual Northern 1100 Drilling program was subsequently designed. This paper shall discuss the practicalities of near-mine target generation in Mount Isa, the issues faced when locating and preparing drill sites in a mature mine environment, and the preliminary results of the drilling program so far.

Jan 1, 2003