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By M Goers, M Almond

"The use of reverse circulation (RC) drilling for grade control sample collection was selected by the Pueblo Viejo Mine Geology department at the recommencement of the operation in 2010. This method was selected because it allows: for multi-bench drilling (60 m hole depth, four benches of mining) to aid mine planning and provide a detailed close spaced drill data comparison with the reserve model angled drill holes to optimise the drill hole interception of the vertically controlled mineralisation dry sample collection in areas of excessive surface and groundwater mining operations to commence with the long assay return period (due to the need for the samples to be shipped overseas for analysis) until the on-site laboratory is operational.To date, 118 302 m of drilling has been completed throughout the operations of two open pits: Monte Negro and Moore. Two drill rigs (contractor and site-owned and operated) with three generations of sampling systems have been used to date. Throughout the drilling a 20 per cent quality assurance, quality control (QAQC) sample check (blanks, field duplicates and standards) have been used to check the drilling and laboratories performance. In addition, a total of 1104 fines samples were collected to compare the drill chip samples collected and the fines lost with two of the sample systems used.The drilling to date has highlighted the need for a complete and coordinated system to be used before sufficient confidence in the quality of the samples collected is achieved.The complete system must be set-up and coordinated to obtain the best quality sample possible. This complete package includes: drill bit size and shape for the rock being drilled and mineralisation targeted face sampling hammers with the correctly sized hammer shrouds sample hose routing to reduce sample flow turbulence and choking blow-down valves to eliminate drill hole water that has entered the drill string during rod changes correct drilling techniques targeting sample quality a sample system that captures the fines for inclusion into the sample.These improvements can be obtained without reducing the drilling rates.The measurements required to demonstrate the improvement in the sample quality will be the focus of future work within the department.CITATION:Goers, M and Almond, M, 2012. Bit to bag - The importance of a total coordinated system in reverse circulation drilling, in Proceedings Sampling 2012, pp 65-72 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 21, 2012

By J Zhang, B Wei, T Zhao, K Wang

Understanding mining-induced surface movement and fissures is critical for environmental protection and geological prevention. In this study, image recognition algorithms, satellite remote sensing and unmanned aerial vehicle photogrammetry (UAVP) were combined to identify surface movement and fissures caused by mining, and a case study was conducted in a coalmine in western China, and the following conclusions were obtained.

Sep 1, 2024

By J Jones

A common problem in the mining industry is that company exploration groups operate in relative isolation to the rest of the company; resulting in poor knowledge transfer (Qureshi and Briggs, 2006) and often priority conflicts with mine geology, operations and project departments. In recognition of this problem, Newcrest created a Minerals Division responsible for stewardship and governance of mineral assets across the value chain from reconnaissance to rehabilitation. It was recognised at an early stage that effective collaboration both internally and externally would be required to improve decision making, deliver faster cycle times and improve governance.Collaboration in companies is generally associated with the introduction of new IT functions. However, modern IT-based collaboration systems and practices are relatively simplistic compared to the long-standing practices associated with collaboration and knowledge management in science and engineering disciplines such as geology and mining.The authors of this paper have started a trial of a 12-point plan for effective collaboration, which recognises that significant efficiencies can be gained and barriers to future success removed if more effective collaboration can be achieved between science and engineering divisions in a company along with external professionals and with the collective intelligence (Tapscott and Williams, 2006) of the outside world. To meet growth aspirations some companies, like Newcrest Mining Ltd, are adopting this comprehensive, step change approach by moving from a closed model the isolates mine geologists to an open and collaborative model that uses IT visualisation systems strategically. The paper describes how an open model provides people with the right work environment and the right information at the right time, which will help individuals and workgroups to work more collaboratively day-to-day. The aim is to achieve speed, focus and mitigate risk through an environment where everyone and anyone can contribute effectively (Cisco, 2008).

Aug 22, 2011

By D Luppnow, C Hore

In-pit tailings storage can provide many advantages when compared to typical above-ground tailings storage facilities (TSFs). As regulations become more restrictive and existing mines expand into new pits, the motivation and opportunities for in-pit tailings disposal is increasing.The Langer Heinrich uranium orebody follows a palaeo-river channel and is mined as an open pit operation. The mine pits intersect two main aquifer systems, one at the surface and one at the base of the orebody/pits. The tailings storage methodology is full in-pit disposal in multiple TSFs for the life-of-mine. Continuity of the initial hydrogeological conditions is incorporated in the design by the use of the pervious surround concept and the reinstatement of the lower aquifer (palaeochannel aquifer) at the base of the pit. Containment embankments are required to facilitate the staging of the TSFs development and are constructed using waste rock liberated during the mining of the pits. All of the TSFs are equipped with decant structures and an underdrainage system is included to improve water recovery, enhance consolidation and increase tailings density.This paper presents the design of a unique in-pit tailings storage solution for the Langer Heinrich mine in Namibia owned by Paladin Energy Ltd.CITATION:Hore, C and Luppnow, D, 2015. In-pit tailings disposal at Langer Heinrich – tailings storage facilities in a unique hydrogeological setting, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 373–380 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

By J Kwak

Driving sustainability concepts and practices into the heart of the design process is the key to achieving a successful, sustainable plant design. Engineering design practices, tools, systems and methodologies should be prepared around true eco-efficiency parameters, adopt wholesystems-thinking and consider life-cycle impacts for the design task. Experience dictates that the application of sustainable plant design practices is most likely to succeed if: The principles are well documented and explained. All stakeholders agree on what sustainability means. Sustainable plant design is treated as a core process. The principals of sustainable plant design are equally applicable in brownfield and Greenfield environments. Although brownfield situations provide the designer with less latitude for change, these types of projects do allow easier measurement and demonstration of relative impacts. This paper further develops the above points by drawing on case studies from HatchÆs repertoire.

Jan 1, 2004

By J Coombes

"In today’s challenging climate of reduced staffing, limited funding and uncertain markets, we are called on to operate more productively and ‘be more innovative’. As an industry, we are quick to identify our practice areas as a mark of our role in the machinery of the mine value chain. We proudly note our profession – ‘geologist’, ‘mining engineer’ or ‘accountant’ – and demarcate our responsibilities and even our physical space. We even subdivide our disciplines into sacred entities such as ‘logging geologist’, ‘resource geologist’ or ‘structural geologist’ to prevent any blurring as though somehow the confusion will cost valuable disciplinary ground. How can we function professionally to heed the call to be more productive and more innovative?The purpose of this paper is to underscore what is expected from project evaluation, examine the ways in which we work as an industry and explore alternatives used in other industries and environments.The paper begins with a summary of project evaluation expectations and the ways in which disciplines typically interconnect when conducting project evaluations. Next, the paper examines alternative work frameworks and making a distinction between multidisciplinary, interdisciplinary and transdisciplinary frameworks. In-practice examples of these frameworks in alternative industries and contexts provide evidence for application as well as an opportunity to examine their pros and cons.The paper closes with a call to re-examine working practices in the mining industry, with a view to enhancing productivity and heeding the call for greater innovation.CITATION:Coombes, J, 2016. Transcending the mining discipline divide – multidisciplinary, interdisciplinary or transdisciplinary?, in Proceedings Project Evaluation 2016, pp 2–10 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 8, 2016

By G M. Volkmann

Pipe umbrella support systems – also called canopy tube systems – have been used successfully for tunnelling in challenging ground conditions since the 1970s. Historically, the drilling unit was the limiting factor for pipe umbrella installations – less attention has been paid to pipe couplings and their influence on labour time and load-bearing capacity.This contribution investigates the influence of the type of pipe connection on the load bearing characteristics of a connected pipe and discusses associated influences on design calculations and installation performance. Standard thread connections reduce the effective cross-section and thereby load-bearing capacity in the connection area. To achieve design parameters, over-dimensioning of the un-weakened pipe section is the only way to overcome this limitation. Recently, two new, alternative connection types were designed and developed for connected pipe umbrella pipes. The first one is the nipple coupling, consisting of fitting with a threaded connection that is pressed and welded into the ends of standard tubes. The second type is the squeezed connection, which mechanically connects non-threaded pipe ends, achieved by force-fitted squeezing from the drill rig. Both coupling types have technical as well as operational advantages compared to the common thread couplings, which are the weakest point in the support system.In the following sections significant technical differences are explained, design values given and a site example presented to illustrate the operational advantages of the newly developed coupling?type.CITATION:Volkmann, G M, 2014. Development of state-of-the-art connection types for pipe umbrella support systems, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 333–338 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By O Ishiyama, L Lu

Sintering is the most economic and widely used agglomeration process to prepare iron ore fines for blast furnace use. Due to the depleting reserves of traditional high-grade iron ore, there have been considerable changes in iron ore resources available throughout the world, especially in steel mills in East Asia. Corresponding to the changes in the availability of iron ore resources, the amount of impurities in iron ore has been slowly increasing. Some of these impurities have been found to have deleterious impacts on sinter quality and sintering performance. In the meantime, an increasing number of large blast furnaces with inner volumes of more than 5000 m3 have been built that require more sinter and are often more demanding in terms of the quality requirements of the ferrous materials. Finally, sinter plants are facing increasing pressure due to more stringent regulations regarding their environmental impact. This paper gives an overall review of a variety of technologies developed worldwide to tackle the changing raw material characteristics and mitigate emissions from sintering operations.CITATION:Lu, L and Ishiyama, O, 2015. Recent advances in iron ore sintering, in Proceedings Iron Ore 2015, pp 61–68 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

The N3500 orebody is the northern continuation of the 3500 orebody at Xstrata Copper's Enterprise Mine and occurs at a depth of 1.3 to 1.8 km. At the nearby S3500 orebody, extreme deformation was observed in access drives where there was a high number of bedding planes per metre combined with either graphite or talc infill. The observed failure mechanism was largely controlled by the geometry of the inclined bedding submitted to high horizontal stresses. Due to the anisotropic strength and deformation behaviour of the shale rock mass, traditional isotropic methods of geomechanical property estimation based upon GSI are not appropriate. A numerical modelling approach, based upon the distinct element codes UDEC (2D) and 3DEC (3D), has been developed to accurately simulate the failure mechanisms and deformation observed in the initial infrastructure surrounding the N3500 orebody.

Nov 25, 2010

By K Mayank, A N. Mainza, I Govender, M Narasimha, A Mittal

In mineral processing industries grinding is the most energy-consuming process. A tumbling mill is an essential grinding equipment widely used for particle size reduction. Power consumption, impact forces and trajectory paths are critical parameters for characterising a tumbling mill to determine grinding efficiency. The effect of lifters and mill speed plays a vital role in such parameters. However, most of the studies ignore the impact of the lifter and do not investigate the effect of slurry dynamics on charge motion. The focus of the present work is to prepare a computational model that can accurately predict the complex multi-phase dynamics of charge particles, air and slurry inside the mill using a model that couples computational fluid dynamics (CFD) and the discrete element method (DEM). The details of impact forces with lifter profiles and mill speed variations will be refined even further using the CFD-DEM coupling approach. The slurry-air free surface is modelled using the volume of fluid (VOF) method, and the charge motion is modelled using the DEM. The phases are coupled using the interface momentum exchange between the charge and the fluid slurry. The coupled model is validated against experimental results from the positron-emitting particle tracking (PEPT) data. The validated model compares the effect of slurry content on charge dynamics with the dry DEM model. The presence of slurry is observed to dampen the tangential and shear contact forces.

Aug 24, 2022

By G Zhang, I Glacken

Multiple indicator kriging (MIK) has been used in the minerals industry for some decades. As one of the non-linear estimation methodologies, MIK has advantages related to resolving multiple or mixed populations, high variability data and strongly skewed distributions. Applying the MIK methodology requires a lot more effort when compared to other non-linear methodologies, for example localised uniform conditioning. This is due not only to the variogram modelling for multiple indicators, but the validation is also very important because the panel model is fundamental for follow-up work, including the generation of recoverable resources at the local or SMU scale. Apart from this, only a few reported case studies of MIK have documented post-processing of the estimated modelled distribution, representing the probability distribution at point scale at un-sampled locations. The MIK post processing should include the change of support from the point scale to the panel scale, and then the extraction of quantile values from the panel conditional cumulative distribution function (CCDF) for localisation of grades into the SMUs within each panel, based on a ranking estimate marking the SMUs from high to low. In this paper, we present a case study on a gold deposit with the MIK method with full-post processing implemented for recoverable resources. The MIK point estimate was carried out with an indirect lognormal change of support from point to panel scale, and localisation was done with a custom script. The localised uniform conditioning (LUC) method was also applied for comparison purposes. The comparison shows that MIK has advantages compared to LUC when comes to capturing the high-grades, especially when mixed or varying anisotropy is present within the mineralisation.

May 24, 2023

By C S. Kelsey, J R. Kelly

Australia is presently enjoying the fruits of a booming iron ore market. Expectations are that market strength will be supported in the short to medium term by increasing feedstock demands from steel mills, as world economies rebuild post-Covid-19. However, as cost and environmental pressures increase the longer-term market outlook will be dominated by product quality. The ‘flight to quality’ will place increasing demands on direct shipping ore miners as they compete to maintain their standing in the iron ore marketplace. China will progressively disengage from its dependence on Australian imports, leaving miners under increasing pressure to boost product quality and diversify outlets globally. Australia has vast deposits of low-grade magnetite ores located mainly in remote and arid regions of the continent. This paper proposes a dry grinding and magnetic separation process to produce premium concentrate grades from the low-grade ores, to assist in meeting future product quality demands. The premium grade concentrates could be either blended with lower quality direct shipping ores or marketed separately. The proposed dry concentration process involves the pairing of Vertical Roller Milling (VRM), a mature technology widely used in the cement industry, and Planar Magnetic Separation (PMS), a new methodology, which has been developed to the threshold of commercialisation by the private Australian company Cyclomag P/L. Two laboratory prototype planar magnetic separators with field strengths of 1800 gauss and 6000 gauss have been built and tested on a range of magnetite ore types over the past three years. In each case, following grinding to liberation sizes, a combination of roughing and cleaning operations has produced pellet grade concentrates. Vertical roller milling has competed successfully with conventional media milling in grinding cement clinker, limestone and blast furnace slags. A key advantage of dry VRM/PMS processing is its potential adaptability to stepwise modular development, which can minimise initial capital investment, while generating early revenue streams to cope with unpredictable market volatility.

Nov 8, 2021

By M Reid, H Arbon

Hillgrove Resources (HGO) commenced open pit mining in 2011 and from 2011 to 2016 the geology team experienced a consistent negative reconciliation between grade control estimated copper (Cu) grade and the mill received grade. For the first four years, despite trialling various grade control strategies, the monthly variance between geology and mill copper grades fluctuated between -5 per cent to -17 per cent Cu metal depending on the style of mineralisation.In 2015, HGO embarked on various measures which resulted in changes to grade control practices under the advice of consultants. These changes to grade control sampling, estimation and block out practices resulted in six to seven months of consistently poor Mine to Mill reconciliations from -25 per cent to -28 per cent Cu.In an effort to mitigate these poor reconciliations the geology team reintroduced the preconsultant block out and geology driven grade control methods. Blockout reconciliations from this point emulated those seen originally from -8 per cent to -12 per cent (Cu per cent). Early in 2016 the geology team introduced conditional simulation for grade control as opposed to ordinary kriging to better characterise the grade distribution, introduced separate estimation parameters appropriate for every zone of mineralisation, implemented a maximum profit function to optimise the selection of ore and waste, and retained the geology driven block out processes. Since March 2016 the mine has experienced consecutive months of positive Mine to Mill reconciliations, the first seen in six years. Year to date the expected copper metal is within 1 per cent of mill reconciled copper metal.This paper will compare the various sampling methods, estimation algorithms and block out procedures from the past six years to arrive at a robust open pit operating procedure applicable for mineralisation with high short scale variability.CITATION:Reid, M and Arbon, H, 2017. Setting new standards at Kanmantoo – effective grade control procedures, in Proceedings Tenth International Mining Geology Conference 2017, pp 401–408 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By P Wilson

The Mt. Wright Underground Mine is located near the town of Ravenswood in North Queensland and is operated by Carpentaria Gold – a wholly owned subsidiary of Resolute Mining Limited. The establishment of the world’s first Sub Level Shrinkage (SLS) mine from a tradition Sub Level Open Stoping operation has proven to be a geotechnical challenge which has required tailored solutions to overcome unique issues. This paper will be broken into two distinct sections that will outline: a brief overview of the mining method and how the SLS method was chosen; and how the SLS is managed and key geotechnical learnings. The story of the world’s first SLS originated from the need of a bulk mining method to ensure the viability of Mt. Wright into the future. Traditional bulk mining methods such as; Block or Sublevel Caving were originally ruled out due to the low natural ‘cavability’ of the orebody and the proximity of the orebody to existing major infrastructure (Decline, Ventilation Rises and Egresses). The first section of the paper will outline the key geotechnical information that helped decide the SLS method in addition to how continuous backfill influenced the design. The second section is intended to address issues that the geotechnical engineers encountered since the inception of the SLS. The feature topic of this section is mining induced stress. Like most bulk mining methods, Mt. Wright had success when the production front was running parallel to the stress (production front being ‘shadowed’ from the stress). This was until a design change, forced by a splitting ore body resulted in this shadowing effect becoming harder to achieve. As a result, rehabilitation and production hole re-drilling become a regular occurrence, which teamed with a strict set of access controls made the production cycle longer and harder to complete. CITATION:Wilson, P, 2018. Mt Wright – geotechnical learnings from a sub level shrink, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 119–132 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By D Kent, R Paine

"Automated mining systems are increasingly being seen as a key requirement for a productive mining operation in the future. The importance of an integrated communication network infrastructure to support such systems is growing.This paper outlines the introduction of automated mining systems in large conventional mines as well as their growing role in block cave mines currently operating or being developed. The paper will then focus on a case study of how the communication infrastructure is fundamental to the operation of such systems and explain why the resultant communication networks require much more than just increased bandwidth (data capacity) to properly support the automation system within the overall mine operation.Mining operations already embarking down this road are discovering that the required network must be based on a true enterprise level architecture to not only enable the mine’s current plans for remote and automated mining, but also provide a scalable and integrated platform for future developments and requirements. The emerging issues for the communication network to truly support automation systems include: increased complexities of operating and maintaining multiple networks integration issues with disparate systems problems with reporting particularly as demands for corporate reporting and compatibility with enterprise systems become the norm ongoing management challenges, which will only increase with the proliferation of new technologies.The paper will explore how certain mining operations are addressing this by adopting a long-term strategy for automation deployment, which includes laying the necessary foundation architecture to meet their current requirements, while supporting their future visions for the fully automated mine.CITATION:Paine, R and Kent, D, 2014. Developing the foundation communication infrastructure to support remote and automated mining initiatives in underground mines, in Proceedings 12th AusIMM Underground Operators’ Conference 2014, pp 151–158 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 24, 2014

By M Nagarajan, S Esen

This paper presents three case studies from three surface coalmines. The first case study is from a coalmine where a dragline operates in 60 m wide and 1 km long strips. Typical overburden height ranges from 30 m to 50 m. The base case blast was modelled using an advanced blasting model (Distinct Motion Code – DMC) to establish the baseline using the blasting parameters in use before optimisation. DMC was used to model the alternative blasting scenarios to obtain the following key objectives:the post-blast muck pile profile was required to have an optimum height of ~28 moptimise cast percentageachieve a well-fragmented muck pile for the draglinethe muck pile profile should be appropriate for the dragline entry into the strip.Achieving these objectives would optimise the dragline performance through reducing rehandle and improving advance along the strip. DMC modelling resulted in the following outcomes:the required muck pile profile could be achievedthe cast percentage increased from 21.1 to 25.1 – a four per cent increaserehandle volumes were reduced.Establishing a good quality assurance / quality control (QA/QC) process was essential to delivering a blast that could achieve these outcomes. The blast was fired successfully and the dragline completed the strip approximately two weeks ahead of the time taken for the previous strip.The second case study is from a coalmine where D11 dozers are used to move the blasted material to the spoil. An optimum profile was required for the dozers for this low-cost mining operation. To achieve this, an electronic blasting system (uni tronicTM 600) was introduced to optimise the muck pile profiles being delivered. The new muck pile profiles showed improved cast percentage from 10.6 per cent to 17.8 per cent. The changes in the muck pile centre of mass displacement improved dozer efficiency as a result of pushing material shorter distances to its final position. Dozer productivity (bcm/h) statistically did not change but coal was being exposed at a faster rate.The third case study summarises the results from a site where dozers are used to minimise the total mining cost. Traditionally, excavators had been used on-site with conventional blast designs. After firing the first cast shot, the blasted material was found reasonably well-fragmented. Although dozing productivity hasn’t been quantified on-site, operators were providing positive feedback (easier push) due to the reasonably good muck pile profile suiting to the dozers. This site also realised significant savings with the dozing as compared to their truck/shovel operation.CITATION:Esen, S and Nagarajan, M, 2015. Muck pile shaping for draglines and dozers at surface coalmines, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 409–416 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By D R. Anstey

The mining of magnetite iron ore in Western Australia will generate large volumes of waste rock and tailings over many decades. The need to dispose of these materials will result in massive waste landforms that will require significant planning and management. The formation of comparable man-made landforms is relatively common, as exemplified through past practice in gold and iron ore (haematite) mining. Unfortunately, the performance of these landforms, with respect to long-term stability (erosion resistance), the release of low pH seepage water and aesthetic impact, has commonly been disappointing and environmental legacies have been created as a result. Lessons that have been learnt from past, large mining operations indicate that there is a need to rethink the methods of waste disposal and landform development applied to magnetite mining. The environmental compliance criteria applied to magnetite mines for the storage of tailings and waste typically include minimising dust generation (particularly as the tailings and mine waste may contain asbestiform minerals), control of silt, minimising visual intrusion and management of potentially acid forming materials. In addition, the climate of Western Australia and the paucity of both surface and groundwater in the vicinity of the magnetite mines frequently necessitate water consumption to be minimised. This paper discusses the potential to co-mingle magnetite mining waste streams in a variety of ways to concomitantly satisfy the environmental compliance criteria and the operational requirements of the mine. These methods include co-mingling of coarse tailings and waste through dry-stacking, deposition of tailings as a paste, co-disposing of all wastes to form an integrated landform and the co-mingling of all waste streams to produce PasteRockTM (a blend of tailings paste and crushed waste rock). The paper demonstrates how these techniques can be applied to the magnetite mining industry to provide better outcomes than might be achieved using more conventional techniques, currently employed in large-scale mining operations.

Jan 1, 2009

By R Austerberry, S Green

The discovery of the Cuffley Lode at Mandalay Resources Costerfield Operations provided an opportunity to extend mine life via mining the offset depth extension of the previously worked Alison Mine. Access from the existing Augusta Mine placed the initial Cuffley underground workings at approximately 250 metres depth from surface. As the new orebody transitioned towards production, a secondary means of egress needed to be established. The depth of the initial capital development presented a challenge in establishing a secondary means of egress that could be confidently relied on. The availability of land to locate a surface shaft collar further reduced available options and geotechnical drilling further limited suitable shaft locations. Time limiting factors such as permitting and having a secondary means of egress in as soon as possible, further highlighted that an innovative secondary means of egress was needed. A consideration of using an emergency gig lowered by a suitable sized crane supplied by an external crane contractor was investigated and found to be a suitable outcome. This Emergency Gig was deployed via the Cuffley Return Air Raise. When trialled, the emergency gig was found to provide a reliable, repeatable extraction method with an acceptable level of risk. Issues discovered during such trials further improved the process to a point where this extraction method became the adopted secondary means of egress for additional lodes that existed at depth. When assessing possible methods of secondary means of egress, the use of a third-party crane and custom designed and fabricated emergency gig should not be discounted. Where a crane can be sourced within an acceptable timeframe, the emergency gig extraction method provides a reliable safe and cost-effective means of secondary means of egress, especially when multiple shafts are to be developed. Local laws may negate the ability to employ such a system, although it is believed with good communication and well-constructed risk assessments, this system can be safely deployed.

Mar 15, 2021

By O van Baalen

The Ernest Henry Mine is a copper-gold open pit operation situated in northwest Queensland, Australia. It is owned and operated by Xstrata Copper, with a current throughput of 11 Mtpa, however, open pit operations are scheduled to cease in mid 2011. The deposit dips approximately 45º and extends for at least another 400 m vertically below the final 530 m deep pit design.Construction and development of a sublevel caving (SLC) operation beneath the open pit was approved in December 2009. The feasibility design requires 39 km of development to be completed prior to production, which will commence in the fourth quarter of 2011. Initial ore production will be trucked and will increase to 3 Mtpa by the end of 2012, after which a hoisting shaft will be used. Ore production will then increase to 5 Mtpa in 2013 and ultimately to 6 Mtpa in 2016.Two 3000 kilo watt of refrigeration (kW(R)) modular refrigeration plants will be installed, as well as two 1600 kW mixed-flow fans capable of a combined flow rate of 780 m3/s at a total pressure loss across the mine of 2000 Pa. The main fans will be installed underground and will exhaust into the base of the pit.The following challenges were faced in the development of the ventilation and refrigeration network:•a relatively steep geothermal gradient,•tropical ambient conditions,•working under a wide pit shell, and•a large underground trucking fleet prior to shaft commissioning.A considerable number of ventilation studies were conducted with later studies extensively using Ventsim Visual™ mine ventilation software to complete the design process of the ventilation and refrigeration networks, including the comparison of several alternative designs. The paper focuses on design challenges prior to the commissioning of the hoisting shaft, and discusses resistance optimisation and occupational hygiene-related design parameters, such as heat and diesel emissions, production level ventilation, main fan selection and location, and refrigeration requirements.

Mar 21, 2011

Performance trials followed the commissioning of three large mine fans at Mount Isa in 1965. Actual performance characteristics were determined. These were in good agreement with predicted performance. Piezometer rings for volume flow and pressure measurement were calibrated, and the performance of some aerodynamic components of the installation was studied.Test equipment, preparation, and conditions are described.

Jan 1, 1967