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By E Corpuz, J Weissman, S Winter, R Evans

The surface-to-inseam (SIS) directional drilling technique has been utilised at Oaky Creek Coal for more than a decade to predrain both the Oaky No 1 and Oaky North mining areas. The cumulative drilling program constitutes a total of 140 lateral and 200 vertical holes, and 405 km of lateral drilling.The use of SIS gas drainage has been successful with the following site-specific benefits being recognised:ability to drain German Creek seam gas contents to residual gas levels of new mining areas within an 18-month period from commencement of well productionstructural geological verification of the mine design well in advance of development mining occurring in an areaability to conduct successful predrainage of the overlying Aquila seam to reduce subsequent goaf emissions.Appropriate and up-to-date geological knowledge during the design and drilling process is a significant influence to achieving success. Vertical production wells need to be located in a position that is most effective to remove water from hole. The lateral hole should not include intersections with significant geological structure.SIS drilling provides continuous seam roof/floor data to help define seam geometry and locate geological hazards with high accuracy. In faulted ground and with variable seam gradients, SIS data can resolve geological ambiguities from seismic sections and enhance seam correlation that would otherwise be available only from discrete and closely-spaced infill vertical exploration drilling.Here, we review some examples of SIS configurations and practice to highlight key learnings in drilling long inseam holes (up to 1900 m per arm) ahead of development and mining. Aspects on prerequisites, evolution of network design, tolerances and drainage outcomes in a variety of geological situations are discussed as technical basis towards a viable and effective SIS drilling program.CITATION:Corpuz, E, Evans, R, Weissman, J and Winter, S, 2015. Surface-to-inseam (SIS) drilling at Oaky Creek coal mine – SIS design aspects and drilling environment, in Proceedings The Australian Mine Ventilation Conference, pp 93–104 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By I Canbulat, A Mcquillan

This paper presents a parametric analysis showing the impact of virgin in situ stresses on a shallow (less than 100 to 150 m) high slope in a jointed sedimentary rock environment. Slope stability is assessed at varying ratios of slope orientation and horizontal stresses. The results of this study indicate stress conditions should be included in stability assessments of excavated slopes, particularly where structure is orientated perpendicular to the direction of horizontal stress. Some consideration of stress state is applied in deep open cut pits (eg those with planned excavations of 400–1200 m) (Myrvang et al, 1993; Stacey et al, 2003; de Bruyn et al, 2014; Kozyrev et al, 2015). Dodd and Anderson (1972), Kalkani and Piteau (1976), Lee (1978), Coulthard et al (1992), Noorani et al (2011) have studied the effect or horizontal stress and its impact on slope stability, showing that tensile stresses tend to develop at the crest of the slope, with larger tensile zones for higher horizonal stresses and steeper slope angles (Stacey, 1970, 1973; Sjoberg, 2013). However, the consideration of virgin stresses on shallow slope stability is less frequent (Lynch et al, 2005; Dight, 2006; Lucas, 2006; Sjoberg, 2013). This has led many geotechnical engineers to believe the impact of virgin in situ stresses on open cut slope stability is minimal and not worth time or consideration in modelling, or their effects on slope stability are still poorly understood (Stacey et al, 2003; Sjoberg, 2013).

Nov 29, 2022

By R Wynn, N Stoitis, R A. Lauten, H Liang

At the Century mine in North West Queensland, MMG produces lead and zinc concentrates. The current production rate is close to 500 000 t of zinc per annum. Graphite is the main gangue in the orebody and a substantial quantity of chemicals are used to achieve an acceptable depression of graphite and other gangue materials in the current operation. In the future, it is anticipated that the content of graphite in the orebody will increase while the zinc grade will gradually drop. This scenario illustrates the importance of an optimised suite of flotation chemicals to maximise concentrate grade and recovery. As an alternative to the current reagent suite where dextrin is used to depress graphite, laboratory test work and subsequent plant trials were conducted with alternative depressants. These depressants facilitated both graphite depression and elevated zinc grades in the rougher concentrate. As an added benefit, it was also observed that the silica content in the zinc concentrate was reduced in the presence of the biopolymer selected for the plant trials. Results from both laboratory tests and plant trials will be discussed to illustrate how this change of reagent suite improved flotation yield at the MMG Century Mine.CITATION:Wynn, R, Lauten, R A, Liang, H and Stoitis, N, 2014. A change in graphite depressant to improve the recovery of zinc at MMG Century mine, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 179–186 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By M Binks

The Fosterville Gold mine is located approximately 20km to the East of Bendigo in central Victoria. The gold at Fosterville occurs as solid solution within disseminated arsenopyrite and pyrite. The Fosterville ore bodies contain various amounts of native carbon in the form of bituminous coal. This carbon (Non-Carbonate Carbon or NCC) has been the predominant mechanism for gold loss from the processing facility through”preg-robbing”.Processing of the Fosterville ore is achieved initially through crushing, grinding and flotation to extract the sulphides. The sulphide concentrate is oxidized using Bacterial Oxidation, before being leached in a conventional CIL circuit. A high portion of the native carbon (NCC) in the mine ore is naturally hydrophobic in nature, and subsequently reports to the flotation concentrate stream, and ultimately onto the CIL circuit. This NCC has a notable preg-robbing ability. Treatment of Black Shale ores, which have elevated NCC levels, has historically resulted in CIL recoveries as low as 35%, with around 60-80% of the gold loss from the leach circuit attributed to preg-robbing.Standard technologies for dealing with a carbonaceous leach feed have been trialed with limited success. The discovery of the significance of heat on leach recoveries, triggered extensive testwork on a range of leach feed and tails samples. Pilot plant testing demonstrated that “Heated Leaching” of the CIL tails was the best process with an average recovery increase of 7.5% being achieved. Following a successful pilot study, an engineering feasibility study was completed by Minerva Engineering, and the project economics determined. With strong recovery gains evident and a predicted project payback of 1-1.5 years, approval for the installation of the full scale plant was granted. Detailed design commenced in September 2008 with installation commencing in January 2009. The circuit was successfully commissioned in April 2009.Following commissioning, the Heated Leach circuit has achieved recovery gains of 4-14%, and has proven itself to be a significant contributor to the overall plant performance.

Aug 8, 2011

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 C M. Stewart

Lithium battery electric powered vehicles and machines (BEVs) continue to gain traction inunderground mining use, with predictions they will dominate the underground light and heavy vehicle fleets for some mines within the next decade. There are clear advantages for ventilation systems through reduced heat output and the elimination of harmful exhaust gases and diesel particulates. However, the risks and effects of BEV fire emergencies for underground personnel and ventilationsystems are still largely in the early stages of analysis and understanding. This paper conducts an industry review of a selection of lithium battery fire incidents and research.A research paper review on lihthium fire behaviour, intensity and toxicity will be analysed and comparisons made with equivalent diesel machinery fires for context. Guidelines for mine firemodelling parameters will be offered to assist in predicting the behaviour, heat and emissions from BEV fires, and recommendations and conclusions will be drawn on the specific hazards of lithium battery fires compared to conventional diesel powered machines.

Oct 12, 2022

By F C. D Michelin

Blast fumes are a significant health risk to underground workers, containing several dangerous gases such as carbon monoxide (CO), nitrogen oxides (NOx) and ammonia. To ensure safe working conditions, workers are not normally allowed to re-enter a mine until the gases are cleared. To predict if gases can be cleared efficiently, simulations can be performed to estimate the gas levels following a blast. For accurate modelling, a calibrated airflow simulation is required in addition to blast-specific parameters such as the yield rate (representing the amount of gas released per kg of explosive) and the dispersion factor (representing how quickly the gases can enter the air stream from the explosive site). Those parameters are not easily determined, as they will vary from blast to blast. Many post-blast gas recordings on mine sites were studied and the correct parameters were determined to ensure an accurate gas simulation. The variability of the results was then analysed and correlation to known parameters is suggested. Finally, recommendations on how to determine the correct parameter are presented.

Oct 12, 2022

By L P. Trout, D G. Reid

PanAust Limited (PanAust) has successfully constructed and commissioned two mining operations in Lao PDR over the past decade and undertaken major studies for three new mine developments. The management of potentially acid generating mine waste and tailings in close proximity of local communities sensitive to water discharge quality have been recurring themes that have confronted PanAust’s project study, development and operational teams. Further compounding challenges, such as the effects of intense annual tropical monsoonal conditions, staging of embankment raises and regular lifting of spillway structures, integrating mine waste and tailings management into production plans and ensuring the long term stability of structures, have been addressed by implementing leading practice management solutions.A recognition of the criticality of managing the substantial business risks associated with these crucial activities led to the early establishment of a governance structure to ensure that the highest standards are embraced for planning and execution. Importantly, these are guided and monitored by a panel of highly experienced and qualified international specialists reporting directly to PanAust’s Managing Director – the Tailings Independent Review Panel. The stewardship process has been effective in identifying potential shortcomings in management systems and has led to enhanced executive commitment to risk informed designs, assurance and overall process rigour.CITATION:Trout, L P and Reid, D G, 2018. PanAust Limited’s approach to mine waste and tailings stewardship, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 135–155 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By M Sciortino, J Korczak, J Muinonen, A St-Jean

The Dumont deposit is a large (1179 Mt reserve), low-grade (0.27 per cent nickel) nickel sulfide project located in the Abitibi region 25 km west of Amos, Quebec. Royal Nickel Corporation (RNC) acquired the project in 2007 and has since taken the deposit through to feasibility. The disseminated nickel sulfide and alloy mineralisation is hosted within the serpentinised dunite subzone of the Dumont Sill; a differentiated, pervasively serpentinised, ultramafic sill of komatiitic affinity. Pentlandite ((Ni,Fe)9S8), heazlewoodite (Ni3S2) and awaruite (Ni2.5Fe) are the dominant nickel-bearing metallic phases and can be recovered by conventional methods (flotation, magnetic separation). Non-recoverable nickel is also present within serpentine and olivine of the silicate matrix.A detailed mineralogical program including 1420 QEMSCAN« samples and 4400 electron microprobe points was undertaken to increase the understanding of the nickel deportment in the various recoverable and non-recoverable phases in a spatial context across the deposit. A total of 105 metallurgical tests have been performed under a standard procedure which have linked the mineralogy to metallurgical performance. This has allowed the creation and modelling of geometallurgical domains on a block-by-block basis to understand the recovery variation and metallurgical performance throughout the deposit. Understanding the spatial variability of Ni deportment in recoverable and non-recoverable phases through mineralogy is the key to understanding metallurgical performance, thus unlocking the value of the Dumont deposit and other large tonnage low-grade ultramafic nickel deposits.CITATION:Sciortino, M, Muinonen, J, Korczak, J and St-Jean, A, 2013. Geometallurgical modelling of the Dumont Deposit, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 93-100 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

By B Olsson, B Reynolds, R Norman

An unprecedented growth in demand for coal exports has placed pressure on multi-user coal chains to guarantee that their capacity expansion projects will meet the required demand. These projects, however, are taking place in an increasingly complex commercial and technical environment - competing rail and coal terminal service providers as well as a myriad of competing mine operators, all needing to operate in an increasingly integrated manner to get the most out of expensive shared assets.Increasing system complexity and integration has driven the need for more holistic and sophisticated analysis tools. The capacity of coal chain subsystems, such as mine, rail and port, can no longer be determined effectively in isolation. Understanding the nature of the interactions between these subsystems, their sensitivity to uncertainty and the resultant capacity of the integrated system is the key to both maximising value and minimising risk.Recently, TSG has worked closely together with the Integrated Logistics Company and a number of key stakeholders in the Dalrymple Bay Coal Chain to develop independent system master plans. These master plans have provided a quantitative and rational assessment of coal chain capacity in its current state and a prediction of its capacity once a pipeline of committed capacity improvements is in place. This paper provides an overview of the study and a comprehensive guide to the process required to effectively achieve valuable strategic insights in a challenging multi-user stakeholder environment.CITATION:Reynolds, B, Olsson, B and Norman, R, 2012. Using independent system simulation to mitigate risk in the Dalrymple Bay Coal Chain, in Proceedings Project Evaluation 2012 , pp 77-84 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 24, 2012

By J Kinal, I Mitchell

Many flotation plants use pH to adjust the pulp chemistry of their system to achieve optimum separation. For example, in a sequential lead/zinc circuit the pH during sphalerite flotation is increased to 10.5 or greater to depress galena and pyrite, thereby improving selectivity for sphalerite. However, maintaining a pulp at a particular pH value does not necessarily provide the operator with an abundance of information regarding the chemistry changes occurring within a plant. This paper provides the reader with a number of pulp chemical observations in several plants, showing that the same trends are noted over time; however, the magnitude of the measured values do change. Further, the changes in magnitude are invariably associated with a change in mineralogy. Thus, is measuring pH enough? Can the Eh, dissolved oxygen and temperature be measured at the industrial scale reliably? And, are these measurements useful?

Jan 1, 2006

By G Wyartt

In the Pilbara region of Western Australia, an iron ore mine is undertaking a high wall cut-back to improve stability and allow access to deeper ore deposits. Several sections of the wall have been classified low factor-of-safety due to unstable localised geology, and therefore an engineered approach to vibration critical blasting was required. The use of electronic detonators allowed multiple signature (seed) holes to be incorporated into a production blast adjacent to the low factor-of-safety area, therefore providing baseline vibration data to be used for future modelling with the added advantage of eliminating unnecessary pit closure downtime typically associated with a signature hole program. All subsequent blast patterns also incorporated multiple signature holes to provide additional data and allow continual updating – and therefore improved accuracy - of the blast prediction model. Electronic detonators and blast initiation systems were combined with advanced blast vibration modelling software to produce optimal timing sequences with predictable vibration outcomes. Although minimising vibration was the primary focus, blasting induced frequency was also a concern for the project team and therefore initiation sequencing was optimised to also avoid undesirable frequencies. Minor variations in ground factors (vibration transmission and attenuation) were noted, and therefore justified the inclusion of regular signature holes which allowed continual vibration model updates. Blasting results produced vibration and frequency measurements within allowable limits and closely resembled the predictive model. These positive results were achievable through the combination of electronic detonators, advanced modelling software and good onsite practices by engineering and on-bench teams alike. This project will remain ongoing as the pit progresses to deeper benches, and therefore the same methodology will be applied; quality and continual data collection, the use of electronic detonators, and optimisation via advanced vibration and frequency modelling software. CITATION:Wyartt, G, 2018. Vibration control blasting for low stability final walls, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 504–510 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By A L. de Ambrosis, S J. Clarke, R Bertuzzi, J Redelinghuys

The M2 Upgrade Project involved widening 15 km of the existing M2 Motorway, which is a key route in Sydney’s road network. The Norfolk Twin Tunnels in North Epping convey traffic over a 460 m length of the motorway. The project involved widening the twin tunnels to provide a third lane and breakdown lane in each direction.The widening of the tunnels was fundamentally different to other ‘greenfield’ tunnel projects in that the operation of the tunnel was maintained throughout construction, with motorway traffic permitted close to the excavation faces on a daily basis. The widened works had to integrate with the existing tunnel support, construction details, and mechanical and electrical infrastructure.The existing tunnel afforded the opportunity to review existing ground conditions in the tunnel. Exposures were mapped within the tunnel, and key design parameters were back-analysed from the original monitoring data to provide increased confidence in the assessed impact from the widening works.Traffic capacity of the tunnels was maintained by detailed staging of the works, and included the ability to reopen the tunnels at short notice.A permit to tunnel system was developed to manage the risks associated with re-opening the tunnel to traffic. A comprehensive suite of instrumentation was maintained to provide reliable monitoring data to support this process. Emphasis on the robustness and reliability of tunnel instrumentation provided increased confidence in the adequacy of the tunnel support being installed. The monitoring was routinely compared with design predictions to check the adequacy of the support measures being installed and confirm the design.The approaches and methodologies developed for the widening of the Norfolk Tunnels were effective in maintaining the safe operation of the tunnels throughout the two years of construction, and provide a framework for increasing the capacity of existing tunnel infrastructure in the future.CITATION:Clarke, S J, de Ambrosis, A L, Bertuzzi, R and Redelinghuys, J, 2014. Design and construction for the widening of the M2 Norfolk Twin Tunnels, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 591–602 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By M Costa, L Polizzi

Process optimisation and continuous improvement are usually acknowledged when making a process more effective, efficient and transparent. During the last few decades, thousands of companies around the world have used total quality concepts in order to establish a continuous improvement process in their companies. Typically these companies apply some kind of Kaizen-type tools and expect results in the short term; however, the great majority of companies are poorly implementing these continuous improvement programs.Usually the most common reasons for failure of the program are lack of commitment from leaders, lack of discipline and engagement from the team to follow process and lack of clear targets for the program. When the results do not come at the expected timeline, it is common to simply drop the current process and apply a different approach from another company or consulting firm.This paper will explore some successful cases of companies that have invested time and effort to establish a reliable and sustainable process of continuous improvement. The focus will be case studies of mines and smelters around the world that use the plan–do–check–act (PDCA) cycle to increase productivity with the best services and lowest costs. The main tools and processes used by these companies will be discussed, as well as results achieved.CITATION:Costa, M and Polizzi, L, 2014. Introducing and sustaining a continuous improvement program in mines and smelters, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 55–62 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By P B. Hills, R J. Walton

Geotechnical instrumentation has been implemented as a key step for monitoring and optimising an engineered mine design for managing seismicity at the Beaconsfield Gold Mine. Measurements of displacement, stress change, ground control element load and seismic response of the rock mass allow for back analysis and calibration of critical parameters for feedback into the engineering design loop. Instrument clusters are installed in strategic locations prior to the commencement of stoping in order to determine the nature of the response of the rock mass to stoping. A selection of instruments including instrumented cable bolts and rod extensometers, resistance wire extensometers, hollow inclusion stress cells, vibrating wire stress meters and resistance wire extensometers are used to gather data through a data logging system. The rate at which data is recorded is adjusted to provide more information during periods of anticipated rapid change such as around stope firings or during periods of high seismic activity, and less information during periods of anticipated quiescence. The twofold purpose of the instrumentation is to calibrate the numerical modelling output which forms the basis of the engineered mine design, and to provide an alert mechanism where the behaviour of the rock mass is not what was anticipated, or where the impact of that behaviour may compromise the integrity of the engineered ground control system. The paper describes the location of instrument clusters with respect to stoping, the type of instruments employed and the method of data acquisition. It provides examples of results obtained and illustrates the way in which that information is used to optimise the mine design and manage seismicity.

Jan 1, 2008

By L J. de Lange

As a material asset for mining entities, the resources and reserves (RR) estimation processes are surprisingly underrepresented in the assurance landscape. When press reports expose them being inaccurately reported, or in merger and acquisitions processes, their importance becomes clear. The impact of erroneous RR numbers (both positive and negative) could have a material impact on an entity’s reputation and value.The technical nature and ‘black magic’ connotations of the RR estimation processes are possibly reasons why audit committees are not actively involved with it. Internal auditors avoid the RR processes for similar reasons. Also the traditional approach to obtain assurance on RR is expensive and is therefore only performed when it is absolutely required.However, stakeholders’ expectations of good governance are growing. Part of this increased focus is based on attaining a higher degree of certainty about the current and forecasted position of the entity. Stakeholders are also increasingly more interested in non-financial areas of entities, as the future success of an entity is more than a set of financial metrics.Consequently, the RR estimation processes should be visible on the agendas of audit committees. Monitoring of key controls is required as part of the governance obligations for senior management and the audit committee. So once it is on the audit committee’s agenda, the question then becomes, how will that agenda be supported by an assurance process that is cost-effective?The main objective of the paper is to describe a model of RR assurance that has been effectively applied in some mining companies. The paper discusses one particular approach that provides an audit committee with the required assurance regarding RR processes. The approach ties the assurance needs of the audit committee to the needs of the technical experts in the entity, therefore involving two important figures. It also offers assurance providers with a model to audit ‘through’ the RR processes rather than ‘around’ them. The paper then discusses top-down and bottom-up approaches that provide assurance at different levels of an entity.A governance audit that focuses on the RR processes is suggested as a top-down approach. A bottom-up approach assesses the design adequacy of internal control processes. A hybrid model is described which meets the needs of diverse stakeholders including the audit committee and the RR community.The hybrid model combines the expertise of professionals in both internal audit and RR. The right balance of these skills directed by a singular approach ensures that a credible result is achieved.This approach is not as expensive as some verification approaches used in the industry and can, as a result, be performed on a more regular basis.The last element of the paper looks at implementation of the reporting mechanism. An assurance process aimed at continuous improvement further enhances the robustness and reliability of RR reported by an entity.CITATION:de Lange, L J, 2016. Resources and reserve assurance processes – a framework for improved governance, in Proceedings International Mine Management Conference, pp 21-34 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 22, 2016

By B Stump

Reliable particle size analysis in minerals processing plants is a critical factor to the economic return of a plant. As recovery of valuable minerals is compromised for particles outside the optimal size range, effective and reliable particle size analysis is more crucial than ever, particularly in the current upswing of the global commodities market. Inefficient particle size analysis can lead to excessive over-grinding, thereby significantly increasing energy consumption and reagent costs, whilst negatively affecting process operation, thickening capacity, water recovery and tailings disposal.Australia’s first installation of a particle size analyser in Iron Ore has been monitored with great interest by the industry. Previously, manual size sampling at Rio Tinto’s Paraburdoo fines processing plant involved off-site sample analysis, with a turnaround measured in days. The Outotec PSI® 500 particle size indicator, commissioned in July 2009, takes approximately three minutes per line at site.The paper will include details on the following:• plant description,• sampling design,• PSI® 500 analyser functionality description, and• key learnings from site.

Jul 11, 2011

By J Lea, D C. Kettlewell

The Carina iron ore deposit lies 105 km northeast of Southern Cross, WA. The area designated the Yilgarn Iron Ore Project (YIOP) is comprised of five prospects along an east-southeast trending greenstone belt that extends from the Helena-Aurora Ranges in the northwest to the Yendilberrin Hills in the southeast, over a strike length of approximately 40 km. The YIOP project encompasses the previously identified iron deposits of Bungalbin, Bungalbin East and Mt Walton. The Carina deposit was discovered by Polaris Metals NL in May 2007. The Carina deposit is located within and parallel to the structurally complex northwest trending Mount Dimer shear zone. The volcanosedimentary Archaean-aged greenstone sequence consists of ultramafic and mafic lavas and flows with interbedded sediments dominated by chert and banded iron formation (BIF). Supergene enrichment processes formed a goethite orebody replacement of BIF sequences within a doubly plunging synclinal fold structure. Mineralised outcrops dominated by goethite form a low ridge 1500 m long, up to 90 m wide and drilled to over 200 m in depth. In the vicinity of the Carina deposit, iron occurrences have been identified over at least a 12 km strike length and the exploration potential of the area is identified as 30 - 40 Mt. Polaris Metals began exploration in the area in 2006. Target generation in the area used existing state geological survey maps and regional magnetic survey data to focus on BIF occurrences associated with major structures. Early field investigations resulted in the identification of a large outcrop of predominantly goethite mineralisation at Carina. Detailed geological and structural mapping was completed, followed by close-spaced reverse circulation and diamond drilling. The mineralisation is predominantly goethite with specular and coarse platy haematite localised along structures that cut the goethite mineralisation. Mineralised zones are moderately vuggy and larger cavities occur in proximity to fault zones that transect the orebody. A capping by a thin veneer up to 9 m thick of canga or ferricrete occurs in places. By December 2008, 178 reverse circulation and 11 diamond drill holes (seven surface holes, four tails) were completed. The current JORC-compliant resource estimate is based on assays from 72 RC drill holes and using a 55 per cent Fe cut-off stands as an Inferred Resource of 27.9 Mt at 58.6 per cent Fe, 1.3 per cent Al2O3, 3.7 per cent SiO2, 0.09 per cent P, and 10.1 per cent LOI. Assaying has recently been completed and will be incorporated into a new updated resource later in 2009.

Jan 1, 2009

By A Späth

Active explosion barriers are used to contain and suppress a methane gas and/or coal dust explosion propagation, including localised mine fires. Early research indicated that these active explosion barriers could be used on a mechanised cutting machine, making it the only technology that could suppress an explosion during its propagation phase at the cutting face. Thereby not only adding protection during mining operations but also reducing the development of toxic gases, fatal temperature increase and fatal overpressure build-up. During their evolution over the last two decades, further advantages of Active explosion barriers were proven in mine operations in countries such as South Africa and China. Characteristics such as effectivity, efficiency, mobility and space restrictions allow these systems to be used in various locations within a mine operation, including highwall operations. This improved technology contribution to safer coal mining was recognised by mine operators, workers and regulators. The Queensland’s Recognised Standard 21 (Resources Safety and Health Queensland (RSHQ), 2021) stipulated active explosion barriers as a technology to ensure the safety within their underground coalmines. The mobility and flexible implementation of the active explosion barriers allow a feasible and practical solution for all critical locations for explosion and fire management in an underground coalmine. The conformance to the Recognised Standard can be achieved all underground coal mining operations such as Bord and Pillar, and Longwall mining. This paper describes the conformance, implementation and use of Active explosion barriers for Longwall mining and development as well as Bord and Pillar mining in Queensland’s underground coalmines.

Oct 12, 2022

By M S. Cassola

It’s expected that the world economy will face a stable and continuous growth in the demand of iron ore, reaching more than two billion tonnes per year within the next year. After decades exploiting resources with high content of iron ore, now the industry faces the challenge to exploit and beneficiate more complex ores.According to the industrial practice, the flotation technology is one of the most important and effective beneficiation processes to deal with low-grade iron ores around the world. However, even with this, it is still necessary to search for new processing routes or promote the optimisation of the existing circuits.The broad application of this technology is an outcome that deeply relies on the proper selection of flotation chemicals specifi cally designed for each system. New collectors are in continuous development as flotation performance significantly relies upon their optimisation.The reverse iron ore flotation in Brazil, mainly constituted by haematite and quartz, uses ether amines as collector for silica minerals and caustic corn starch as depressor for haematite. The process selectivity is highly impacted by the features of the etheramine, such as:• mono or di-etheramine,• neutralisation degree,• chain length,• branched or linear chain,• the flotation pH, and• the size distribution of the flotation feed.This paper describes the experience obtained from laboratory and industrial trials on different ores, conducted to improve the selectivity and recovery in the reverse iron ore flotation by selecting the required collector for low-grade ores.

Jul 11, 2011