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By J Li, J Regan, D Payne

The Caval Ridge Mine is an open cut coalmine and located within the Bowen Basin region in Central Queensland, and commenced mining and processing operations in 2014. A number of geotechnical challenges for managing dragline bench and lowwall stabilities have been encountered in both southern and northern pits over the years. Southern Pits contain steep seam dips of up to 15° (27 per cent) whilst the northern pits also have shears below pit floors. Geotechnical guidelines to manage the risk of dragline bench failure and lowwall instability have been developed and improved since these geotechnical challenges were identified. The dragline guidelines include dragline tub offset distances from the 60° Line (SDL) or buttressing thickness for different seam dips greater than or equal to 8°. The low wall stabilisation guideline established floor disruption widths and depths depending on seam dips and presence of floor shears to known depths of up to 3 m. As mining operations advance, lowwalls have remained stable until floor disruptions were fired, then returned to stable soon after the shot. The maximum distance of lowwall cracking with blasting has been as far back as the second spoil peak (the prestrip truck dumps construction limit). These failures need to be eliminated to allow the operational flexibility and haulage benefit of constructing the prestrip truck dumps behind the first spoil peak, while maintaining no risk to personnel or equipment. The floor shear depth was verified by collaborating with the exploration teams and taking advantage of the already planned 8-inch coal quality core holes, drilling them an extra 5–10 m past the coal seam floor and locating the shear presence. With this continuous improvement effort, no lowwall failures have occurred during floor disruption firing from the second strip after the new floor disruption depth guidance have been applied. This paper documents the processes for developing these geotechnical guidelines, operational implementation, and outcomes. Operational applications over the years confirmed that these guidelines have effectively managed the dragline bench and lowwall failure risks related with the steep seam dips and floor shears in this open cut coalmine.

Nov 29, 2022

Safe, efficient production is a common objective for all large open pit mines. Despite comprehensive policies, procedures and regulations aimed at protecting workers, several people die each year in mining equipment-related collisions. The limited sightlines of heavy equipment operators coupled with difficult operating conditions are major contributing factors to the majority of mining equipment collisions. Off road haul trucks are the most common type of machinery involved in surface accidents. These vehicles represent the primary target for improving safety performance by mine operators. Although several commercial products have been introduced to address these issues, none have achieved significant market acceptance. The current collision avoidance solutions lack integration with onboard fleet management and equipment health systems. To achieve acceptance in industry, any collision avoidance system must offer high reliability, minimal false alarms, and value for money. With these criteria in mind, this paper will examine the pros and cons of the various technological approaches to collision avoidance in an open pit mining environment. The unique global positioning systems (GPS) and camera-based proximity detection solution on offer from Modular Mining Systems will be described. This solution uses intelligent filters to minimise false alarms. Tight integration with fleet management provides context information to enhance warnings and enable back-office near-miss analysis. Available today, this combination creates a practical solution to improve the situational awareness of heavy equipment operators, at a compelling price point. Future directions for maximising heavy equipment operator situational awareness will also be examined.

May 1, 2010

This paper reviews recent advances in geophysical tools for mineral exploration. It does not restrict comments to methods which are usually applied in the tectonically active belt surrounding the Pacific Ocean, where geophysics has often been secondary to geological prospecting (eg visual recognition of surface alteration) and drainage geochemistry; but considers geophysical tools applied to a broader range of both deposits and terrains. For example, the subdued topography of much of Australia and Canada has lent itself to the development and extensive application of airborne methods. In Australia, deep weathering and transported cover have necessitated the use of geophysical methods to not only detect anomalies but also to map and understand basement geology. This same weathering has caused specific problems, particularly for electrical methods, but recent improvements in instrumentation, processing and visualisation have largely overcome them. A great deal of geophysical data is now being collected by government agencies, often from the air, and made readily available to explorers. In several Australian states it is free, often on line, and in almost all cases it is relatively cheap. These regional data sets are often augmented by more detailed local surveys in areas of interest. Although æanomaliesÆ are still important much more is being done with the high quality data which is now available The results are used for geological mapping, to test geological hypotheses, to construct detailed 3D geological models and, together with fluid flow modeling, to predict optimum locations for mineralisation.

Jan 1, 2004

By B Ghahreman‐Nejad, M Munro

Design of embankment dams often requires seismic analyses, or an assessment of earthquakeinduced ground and dam movements. There are a large number of cases where earthquakes have triggered sliding and lateral spreading of embankments, resulting in excessive crest settlements. In some instances, liquefaction and embankment failure has occurred resulting in loss of containment. Hence, evaluation of the effects of earthquakes on embankment dams is a critical design aspect. This paper discusses the methods and the results of a seismic liquefaction assessment and deformation analyses of a tailings dam. The tailings dam consists of a perimeter earth core rockfill starter dam which has been raised using upstream construction methods. The embankment raises (formed by an upstream clay blanket and an all-in rockfill body) are constructed over the impounded tailings, which are potentially liquefiable. Extensive field and laboratory tests were undertaken to assess the liquefaction potential of the tailings, and also determine the material properties required for seismic stability and deformation analyses. Numerical modelling of seismic liquefaction and deformation was carried out using FLAC (Itasca 2016) to predict the magnitude and spatial variation of deformations that may lead to an uncontrolled release of tailings. Primarily based on a parametric assessment of UBCSand and Finn-Byrne constitutive models, the results of the analyses are presented and compared for evaluation.

Jul 1, 2021

By Hare S. M, Griffin P. T, O&apos

Chalcopyrite ore and converter slag treatment to produce copper concentrates is undertaken at the Copper Concentrator of Mount Isa Mines Limited. This concentrator was commissioned in May 1973, replacing the original No 1 Lead-Zinc Concentrator, for the processing of all chalcopyrite ore coming from Mount Isa Mine.Treatment of chalcopyrite ore at rates of up to 125 000 l/week is described here; the treatment of converter slag is described later.

Jan 1, 1993

By J Planner

As Australia’s coal and iron ore export volumes increase to meet international market growth, port terminals, mining operations and rail transport systems can be the source of increased dust emission. Current and future sustainable expansion must minimise dust emission from bulk handling and transport operations located in close proximity to residential areas. Lower level dust emissions can be controlled by operational measures such as water addition to products, and use of water spray on stockpile surfaces. Recent research has shown that higher levels of dust emission can be more effectively controlled by understanding and treating the dust characteristics of each individual bulk product. Application of this research, progressively being applied at Australia’s coal and iron ore port terminals and rail transport systems, is achieving compliance with health standards and minimising dust nuisance effects to an acceptable level.

Nov 22, 2011

By A Fern, A Hawkes, o

This presentation will cover: the importance of high-quality safety leadership; insights from a Safety Climate Survey that includes responses from 7903 employees working at 19 Australian mining organisations; the results of a critical control verification (CCV) coaching intervention; and recommendations for improving safety leadership in high-risk work settings. Safety climate is a representation of the deeper culture that exists in an organisation. Safety climate is predictive of behaviour, performance and reporting in organisations. Leaders play an important role in the establishment and maintenance of culture. Perceptions of safety climate were collected from 19 Australian mines (n = 7903 employees). These results indicate that the Australian mining sector is doing well in team support for safety and supervisor safety commitment. There were negative perceptions of willingness to report errors, employee involvement in safety initiatives, psychological safety and emergency readiness. Perceptions of safety leadership were in the fair range, with recognising behaviours perceived lowest, falling in the poor range. The underreporting rate was at 25 per cent indicating that 1 in 4 incidents are not being reported. Analyses exploring climate, leadership, safety behaviour and well-being will also be discussed. The integrity and success of critical risk management systems is often determined by the quality of safety leadership. Leaders need a mix of technical safety knowledge and interpersonal skills to be able to support the workforce to build critical control knowledge that invites open and collaborative discussions to find new or improved solutions. Forty leaders at a major mining operation completed training and 5-weeks of coaching focused on developing critical control verification competencies. The follow-up evaluation demonstrated significant improvements in relationship building, observation of controls and overall capability. Overall, insights from multi-organisation climate data and a prepost coaching intervention will be discussed and recommendations and practical guidance for leaders will be provided.

Apr 16, 2024

By Amanatidis A

In this paper, the kinetics of iron precipitation as sodium jarosite from aqueous solution is investigated. The determination of the reaction mechanism is attempted based on the experimental data of iron removal as a function of time, without using the characteristics of the precipitate.Experiments at the temperature range from 50° to 95°C were carried out with initial conditions of iron concentration IQ g/L, sodium sulphate concentration 25.44 g/L, sulphuric acid concentration 3.68 g/L, pH = 1.5 and agitation rate 600 rpm. Temperature greatly and positively influences iron precipitation from the solution and this is accompanied by pH decrease. The activation energy was determined using the maximum values of the precipitation rate, which were evaluated by polynomial fitting of the sigmoidal shape experimental curves, and it was found to be 44.37 kcallmole. The determination of the rate-controll ing mechanism was based on some criteria used for the discrimination among the three probable mechanisms of precipitation (diffusion, mononuclear nucleation, polynuclear nucleation). These criteria utilise various funetions of the recovery 'a' of iron precipitated versus time, the most important of which are the chronomals. The results of the kinetic analysis procedure showed that the polynuclear nucleation growth mechanism controls the precipitation of iron as sodium jarosite. This was confirmed by the high value of activation energy, excluding diffusion as the controlling mechanism.

Jan 1, 1993

By T Roberts, S Talu

Steel wire weld mesh is a common industry standard surface support used in underground mining, traditionally installed with mining drills during the bolting cycle. As underground mining depth and stress increase, mining methods and their sequences at these depths place challenges on conventional surface support options. These challenges have provided a need for high capacity surface support options that improve development efficiency, reduce the need for secondary ground support installation and is easily installed with current mining equipment. A 5m2 mesh testing machine was built, suspending a 9500kg concrete slab, designed with multiple hold down points to test varying bolting patterns. Mesh load and displacement is accurately measured using a data acquisition system which pushes against the restrained mesh module with an available 200kN load and 1200mm displacement capacity. A testing program comparing conventional surface support, straps and combinations of both were tested for baseline results. New module designs incorporating existing mesh types and new design concepts were manufactured to allow for single pass installation during a bolting cycle. Nine mesh types, mesh/strap combinations and new mesh module designs were compared using the same test method. Based on these results, two high capacity mesh module types are produced. This paper will detail the test program, load and displacement results and underground mesh module performance, describing the two high capacity mesh modules function within the development cycle and manual handling. CITATION:Roberts, T, Talu, S and Wang, Y, 2018. Design and testing of high capacity surface support, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 303–322 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By H Jones

The paper outlines the adoption and evolution of ‘sustainable development’ as a concept in tailings management practices in the mining industry over the last 30 years. Over 500 lives have been lost in tailings facility accidents since World War 2. The paper outlines commonalities in many of these accidents, particularly the role of excess water. It considers the role effective tailings management can play in enhancing the social acceptability of mining in the future.Tailings management is a major operating cost at many mines while the cost of successfully closing tailings facilities is also very high. Current tailings management practices in the industry are outlined. The technical and engineering challenges of reducing potential risks associated with tailings by reducing water entrainment are described. The successful development of practical techniques to better manage tailings and reduce water consumption and wastage are described. For example, water removal in the alumina industry to produce a paste for dry stacking is now a reality.The future adoption of these new risk reducing techniques by the industry is discussed and the implications of the adoption or non-adoption of these techniques on the industry’s future ‘social licence’ is considered.

Nov 22, 2011

By S Ellis

In January 2008 Chirano Gold Mines Limited committed to expansion of the Chirano Gold Project from its existing design capacity of 2 Mtpa ROM ore to a new design value of 3.5 Mtpa. In addition to increased throughput, the design had to contend with increasing ore hardness and competency, while at the same time make cost effective use of existing equipment with minimum disruption to existing production. The solution adopted involved some novel approaches including tertiary crushing and operation of the SABC circuit in overflow ball mill mode and parallel elution with a common acid wash column. This paper describes the approach taken to the design of these elements to achieve a cost effective and safe capacity expansion.

Aug 8, 2011

By R van Wyk

In today’s mining environment the use of heavy mechanical devices and other high-tech electronic devices like two-way radios, cellular phones and even automated mining systems, form a vital part of the daily operations of a mining site. These human-made devices and some of the naturally occurring events, like lightning and gamma radiation, can have negative effects on electronic detonators and the associated control equipment.On larger mining operations the necessity to move the point of safety for blasting further away from the blast area, introduced remote firing via radio frequencies for electronic detonator systems. Other influences on electronic detonators can be abuse or ignorance. To ensure the safety of the end-user, an electronic detonator must be resistant to some common mistakes that users can make. One of main concerns here is resistance to static discharge or incorrect wiring. Despite the daily use of electronic detonator solutions, scepticism and concern still exists amongst those who believe the system raises the risk of a premature initiation of the blast through some form of interference trigger.This paper will help users understand how electronic detonators and the associated control equipment protects itself from external influences. Focus will be on protection schemes to counter static and over-voltage discharge and methods to ensure protection of secure wireless radio links and detonator communications. With well engineered communication systems and solid static and over-voltage protection, an electronic detonator system can be more reliable and safer than other detonator systems. The following main points will be discussed:what makes a detonator an electronic detonator,static electricity and over-voltage protection,the general influence of electromagnetic energy on the detonator,the influence of lightning on detonators,the protection of radio communication’s links as used by remote firing equipment, andthe safety protection features built into remote firing equipment.

Nov 8, 2011

In any strip coal mining operation the aosL important single operating unit is the dragline. Because the capital and operating costs of a dragline are high, it is desirable to operate these machines at their maximum efficiency. Thiess Bros. Pty. Limited operate a Bucyrus-Erie 1350 Walking dragline at their Callide coal mine. The operating conditions at the Callide Mine are different from those of other coal mines situated in Central Queens ,nd. The topography is rugged, the coal seam is thick, and the overburden is hard and inter- HH,inded. Several different operating techniques for a large dragline working under these con- ditinns arc discrossmd it tt

Jan 1, 1978

By S Grimsey, E Janetzki, J Emery

Floor failure on the longwall face is a complex problem due to the dynamic interaction between the surrounding strata and powered roof supports involving multiple variables. It can also be highly problematic and costly when not well understood as there are significantly less remedies available post event. This was the early experience at the case study mine where significant lost time was incurred due to unplanned delays in the first two panels. To detect and prevent such occurrences is clearly the best approach, hence a tool to predict both floor failure occurrence and magnitude prior to mining was developed. Several parameters were determined as the key drivers for the failure events that had been experienced at this site. These parameters were, in list of influence from highest to lowest, material strength, retreat rate and the presence of water. The parameters were evaluated using a semi quantitative risk rating system ‘Heave Risk’ and given a weighting per their apparent influence. This ‘expert system’ methodology was selected as the use of risk rating systems in underground coal mining is well established. The heave risk model was first applied to previously mined panels. It accurately identified all areas of known major floor heave, with clearly defined areas of low and high risk apparent. The heave risk model was then used prior to mining and evaluated post mining based on observed conditions. It was found to also be highly accurate for prediction. The variability of each parameter and its influence on the overall risk rating is illustrated and discussed.

Nov 29, 2022

By M Salu

Ventilation control devices (VCD’s) and bulkheads are critical controls used for managing risk in underground coalmines. Following the Moura No. 2 mine explosion in 1994, the Queensland Mines Department required that the design of VCDs be based on live testing (such as in a mine testing explosion gallery) and more recently on numerical modelling using measured seal material properties. While the stipulated methods represent an idealistic solution, they are not practical to implement as solutions to daily challenges presented in underground coalmines.Not all VCD’s and bulkheads are placed in areas which have been mined to standard roadway dimensions. Operationally, VCD’s may be required to be placed close to intersections or require large dimensionally different areas (eg overcasts and pre-driven recovery road shutters) compared to the live testing or numerical modelling originally undertaken.This paper describes the various structural engineering methods utilised to account for the design of VCD’s where the operational requirements are non-standard. Siting and construction of VCD’s near the entry of cut throughs and geological structures requires additional design considerations. While VCDs constructed from a single material (eg sprayed mining plaster) are relatively straightforward to design, the addition of multiple openings (doors) or large pipes will complicate the structuralanalysis significantly.Temporary bulkheads used for the containment of grout such as for the construction of pre-driven recovery roads in coal mining have a significantly different risk profile to VCDs and should be designed accordingly. Recent failures and near-misses in such bulkheads have highlighted this issuefor the authors.The existence of an Australian Standard for Underground Mine VCDs and Bulkheads would go a long way to addressing many of the issues raised in this paper. Without a single, industry-accepted reference for VCD design, individual mines will have to continueto exercise their best judgements using whatever local expertise is available to them.

Oct 12, 2022

By T Y. Dube

In this paper current net present value (NPV) based mine valuation techniques that take into account market and private risk are discussed and analysed. Potential pitfalls that arise from the application of a portfolio, market or commodity based risk metric to a mining project are identified. An alternative non-simulative framework for quantifying and factoring market and private risk in NPV calculations is proposed and then applied to a hypothetical case study in an attempt to overcome identified pitfalls. Mathematical proof that a static discounted cash flow (DCF) calculation can underestimate or overestimate mine NPV is presented, the conditions for each are outlined and the degree of underestimation defined.CITATION:Dube, T Y, 2012. How the use of market-based risk metrics can undervalue good mining projects and overvalue poor ones, in Proceedings Project Evaluation 2012 , pp 29-34 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 24, 2012

By A E. C Peres, P R. M Viana

The role of flotation columns in comparison with conventional mechanical flotation cells is discussed under the scenario of Brazilian flotation technology. All iron ore concentrator circuits commissioned since 1990 incorporated column only flotation technology in rougher, cleaner, scavenger configuration. Columns were also added to existing circuits, especially at the cleaner stage. Columns were also incorporated to phosphate ore flotation circuits operating mechanical cells. In two phosphate concentrators, columns substituted for all mechanical cells. Columns perform the cleaning stage in a large sulfide copper concentrator, following rougher flotation in tank cells. Scavenger of the cleaner tailings is performed in tank cells at this plant. Other ores that are concentrated in flotation columns include graphite, talc, lead-zinc sulfide, and a zinc hydrometallurgical residue for silver recovery.

Jan 1, 2005

By M J. Noy

The automated measurement of rock fragmentation particle size distribution in the muck during muck excavation has been developing over the last 16 years. The introduction of stereo camera imaging of the muck has provided improved automated particle segmentation for image-based measurement algorithms. Recently, a new vision system processing algorithm has been developed. The inclusion of 2D texture in the analysis has provided a significant improvement in the definition of the finer size fractions, which has resulted in the automated analysis no longer requiring calibration.The previous stereo vision system algorithm required analysis calibration to account for poor ‘small particle’ definition in the 3D surface profile. This was because of the depth perception limitations of the stereo camera system at greater than 8 m. The new algorithm has been implemented on a number of shovel-installed vision systems, and the algorithm’s performance in automated analysis has been assessed against a diligent manual analysis of the same fragmentation images. The new algorithm provides improved distribution resolution and accuracy.CITATION:Noy, M J, 2015. Evaluation of a new vision system algorithm for automated fragmentation measurement from a shovel, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 721–726 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By M Spagnolo, M Ashley, D, L Reemeyer

PasmincoÆs Century Concentrator in North West Queensland commenced operations in November 1999. The nameplate production capacity of 500 000 tpa of zinc metal production in concentrate was achieved in August 2002. Completion of the production ramp up was successful due to the culmination of a number of initiatives throughout 2001 and 2002. Mine to mill interaction to understand and eliminate head grade related bottlenecks affecting Concentrator production and reduce feed variation. Grinding circuit process development û operating and process control strategies to improve stability and reduce grind size to support zinc recovery. Pumping upgrades to control spillage in ultrafine zinc flotation Low density zinc flotation strategy û to improve silica-sphalerite separation to improve zinc recovery while maintaining acceptable silica in final concentrate. Flotation circuit process development û froth crowders, froth cameras and reagent control strategies to improve primary zinc flotation performance. Review and implementation of longer campaigns between planned shutdowns to improve availability. Team reorganisation û to improve setting and implementation of metallurgical strategies. This paper describes these initiatives and their contribution in achieving the production target. It also notes the ball mill motor failures that delayed the successful achievement of the ramp up, and CenturyÆs response to minimise the production impact. The paper also outlines the capital improvement program that was implemented to improve zinc recovery to design 82.5 per cent recovery once the production rate had been achieved.

Jan 1, 2003

This paper addresses the unique environ- mental programmes which prevail at Ranger and their importance in the future profitability, of Ranger Uranium Mines Pty Ltd. (RUM) Industrial relations, general safety, and occupational health have long been regarded as part and parcel of the concept to 'manage for profits'. More recently, the need for environmental protection has also become an important management consideration. This is particularly so at the Ranger Uranium Mine where environmental protection is very closely and continuously regulated. Since the commencement of operations at Ranger some three years ago the company has operated within these regulations and demonstrated clearly that yellowcake can be produced efficiently, economically and safely. The company also recognises that in order to ensure continuity of production, it will have to continue to operate within these strictly supervised Regulations.

Jan 1, 1984