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By N LaBranche

The resurgence of Silicosis and Coal Worker’s Pneumoconiosis (CWP) in coalmines has placed the spotlight back on the management of worker exposure to particulate matter across all mining sectors (Coal Workers Pneumoconiosis Select Committee, 2017). There already exists a substantial body of knowledge on particulate matter and its impacts upon human health (National Academies of Sciences, Engineering, and Medicine, 2018). The contribution of silica to respiratory disease is well known and there is a growing concern for exposure to diesel particulate matter. However, it is also clear that there are major gaps in our understanding. In part, those gaps relate to the contribution to adverse health effects of mineralogical constituents in the dust (LaBranche et al, 2021a). It is also becoming evident that the size and shape of the particulate matter can affect its potential impact on human health.The University of Queensland has developed a methodology for characterising respirable and inhalable dust samples using scanning electron microscopy. Multiple samples from numerous mining operations have already been analysed using the UQ methodology. The process has been successful in showing the variety of mineralogica lcomponents and particle size distributions presentin various areas of the mines.

Oct 12, 2022

By E Kasai, D Maruoka, Y Konno, T Murakami

The iron ore sintering process produces approximately three per cent of carbon dioxide emission in Japan because a large amount of coke breeze is used as the main agglomeration agent. Therefore, its suppression has been required. A promising method is to replace the coke breeze with biomass char and iron-bearing materials. In this study, the effect of the utilisation of metallic iron with coke or palm kernel shell char (PKS char) as an agglomeration agent on its oxidation behaviour was examined by a series of experiments using a sintering simulator. The use of PKS char leads to a larger decrease in the pressure drop difference of the sintering bed compared to the case using coke. Furthermore, the oxidation rate of metallic iron was larger in the case using PKS char together than that using coke. It was considered that the oxidation of metallic iron was promoted because the bed-temperature increased at a faster rate and achieved a higher temperature.

Nov 8, 2021

By A S. Kurilko

For mines located in the cryolitic zone, thermal conditions are an important factor for all kinds of mining works, especially for ventilation of workings. In the present paper, some models of mine air heat transfer considering air distribution in a net of mine workings are developed. A combined solution is suggested for heat transfer and air distribution problems in mine workings and other underground structures located in the cryolitic zone. A software package is also presented for calculating temperature conditions in an underground refrigeration plant and for optimisation of ventilation conditions. This software uses a special 3D mathematical model to describe heat transfer in a freezing chamber between surrounding rock massif and stored product as well as between atmospheric air and the daylight surface of rock massif. A problem requiring strengthening of a backfill material and its thermal interaction with surrounding rocks during underground deposit mining by horizontal layers in conditions of the cryolitic zone is also discussed. The developed program takes into account cement consumption, geometrical dimensions of workings filled and a sequence of deposit mining.

Jan 1, 2005

By D Cai, E Baafi

Various enabling technologies and systems have recently been introduced in the mining industry. Such systems include miner-bolters with concurrent cutting and bolting, employment of two shuttle cars, adoption of self drilling bolts and utilisation of continuous haulage or monorail systems. The paper discusses how Flexsim discrete event simulation models were used to assess how these proposed mining systems can best be used to achieve and sustain high roadway development rates of 10 m per operating hour for 20 h/day.

Sep 26, 2011

By G J. Zhang

The shape and particle size distribution of caved ore mass in sublevel caving were investigated in this study. The paper first reviews the main factors affecting the shape and characteristic of caved ore mass in sublevel caving and then through the experimental blast testing with cement-sand concrete models, the shape and particle size distribution of caved ore mass were found out. The experimental results indicated that the shape and particle size distribution of caved ore mass was similar to that of the drawn loose body. This finding presented a new perspective for the future study on the ore drawing theory and on the optimisation of structural parameters of sublevel caving. The structural parameters must meet the principle that the shape of the drawn body is in consistency to the shape of caved ore mass.

Jul 11, 2011

By M D. Goodz

MacPhersons Reward gold deposit is in a post-kinematic tonalite intrusion which is a setting different from many other deposits of the Coolgardie goldfield that are hosted in early Archaean tholeiitic sills or meta-sedimentary rocks. Gold mineralisation at MacPhersons Reward consists of auriferous quartz veins that are best developed in the tonalite but extend to the adjacent komatiitic rocks and along the lithological contact zones. The gold-related alteration halo is dominated by biotite-chlorite and pyrrhotite. Unlike many other Coolgardie deposits, the As concentrations are low.

Aug 22, 2011

By W J. Haylock, K Wasiel

PX4 Software Pty Ltd is a Brisbane-based company, which specialises in providing tenement management software to mining and exploration teams operating in Australia and several international jurisdictions, including the United States, Africa, and Canada. Whilst the company is experiencing substantial growth due to a demand from both the minerals and mining technology sector, there is a crucial gap in the market for critical minerals, which will be required to achieve the net-zero emissions goal set by the Paris Agreement for 2050. To help understand and address the technology gap identified by the unprecedented demand, PX4 Software undertook the Annual Survey of Technological Transformation in the Exploration Industry. This survey involved interviews with 12 very distinguished subject matter experts in the fields of Geoscience and Geology from across the globe. From this survey, we have defined eight major categories of exploration technologies. Notably, the most transformative of these technologies over the past 65 years falls into the Geophysical Methodology category, specifically focusing on image and signal processing of both airborne and downhole data. Advances in computing power during this period have significantly improved data processing quality, enhancing orebody modelling, and targeting. This has had a profound impact on the industry. Moreover, the survey reveals that future transformative technologies are expected to centre on the automation of existing processes through AI and Machine Learning techniques. This is expected to help facilitate the identification of critical mineral systems and thus enable the exploration industry to make more informed decisions based on data analysis using Machine Learning and AI.

Sep 1, 2024

By G Lumley

PlannersÆ optimism (or maybe commercial necessity) means that most mine plans use equipment rates that are rarely achieved (Lumley and Beckman, 2009). This lack of understanding of what equipment actually moves is causing erroneous equipment forecasts, leading to incorrect mine development plans and economic evaluations. Compounding this problem is a downward trend in actual equipment performance in some areas. Consequently, the presentation of realistic mine plans that are actually achieved in practice is not a common occurrence. However, rational, fact-based mine planning is available to those who want it. Hundreds of millions of cycles of data from open cut mining equipment has been collected from mines around the world since 1992. This unique and highly valuable databank is growing at an exponential rate and is being used by a number of our big miners to support rational and fact-based decision-making. However, neither the use nor the appreciation of the value of this data is universal. There is a challenge to everyone in the mining industry - how do you access value from it? The databank was drilled into and the results analysed for, the Australasian Mining and Metallurgical Operating Practices (AMMOP) publication (Lumley, in press). For this paper the analysis has been extended to include interpretation of trends for draglines, shovels, excavators and trucks. It investigates trends between coal and non-coal mines and across geographic areas. It is known that mining equipment performance in most sections of the industry is falling. This paper attempts to quantify the fall and provide explanations. The trends are analysed to extract the reasons behind the changes and most importantly, what can be done about it.CITATION:Lumley, G, 2012. Understanding trends in performance of open cut mining equipment, in Proceedings Project Evaluation 2012 , pp 203-224 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 24, 2012

By K Muller, T Oosthuizen

Blast exclusion zones are instrumental in protecting equipment and personnel. When there is no constraint in footprint, the exclusion zone can be enormous, practically eliminating the hazard of flyrock. Unfortunately, this may not always be the case and in many circumstances the blast design needs to be altered to suite such scenarios. When a conservative design approach is taken, it could completely eliminate any form of ejection, whether it is from the free face or the bench itself. The degree to which typical flyrock models describe fragment motion through air with ballistic flight equations are not justified when such a high level of control is applied. This paper examines various methods of risk analysis and suggests an approach to be used for controlled blasting.The outcome of principles discussed in this paper can be seen in video form (Mavmedia, 2014).CITATION:Muller, K and Oosthuizen, T, 2015. Should the blast exclusion zone be based on a qualitative or quantitative analysis? A practical implementation conundrum, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 425–428 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By T Craske, J Sykes, T C. McCuaig, M Jessell, A Trench

The prevalent strategic approach in the mining industry is one of planning. However, it is widely recognised that planning does not work in complex and uncertain situations (Mintzberg, 1994), such as those associated with ‘above ground’ non-technical orebody complexity (Trench, Packey and Sykes, 2014). Mintzberg, Ahlstrand and Lampel (2009) suggest the focus instead should be on strategic ‘thinking and doing’ and using the many ways to think about strategy to make sense of complex, uncertain, and unique situations. They therefore place great value in cognitive flexibility. Scenarios development utilizes several different thinking styles and thus assists with this type of flexible strategic thinking (Figure 1). The ‘Centre for Exploration Targeting (CET) Scenarios’ were developed with the ‘Oxford Scenario Planning Approach’ (OSPA) (Ramírez and Wilkinson, 2016). The OSPA aims more to improve the thinking skills of decision makers, rather than forecasting per se (Wack, 1985a, 1985b). As such, this paper focuses less on the content of the scenarios and instead on the practical value of scenarios in strategizing. CITATION: Sykes, J, Trench, A, McCuaig, T C, Jessell, M and Craske, T, 2018. Strategic thinking about long-term ‘above ground’ orebody complexity using scenarios, in Proceedings Complex Orebodies Conference 2018, pp 60–64 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By P Aguilera, C Guerrero, M Tucker

With the advent of Electronic Detonator Systems in the global mining industry, as well as the development of high precision pyrotechnic delays, the measurement and analysis of delay performance (usually measured in terms of dispersion about a batch mean û precision, and the deviation of that mean from the nominal detonation time û accuracy), has become an important issue. Through the non-conventional use of existing Velocity of Detonation (VoD) measurement technology, it has been shown to be feasible to measure the precision and accuracy of delay detonator series connected in the same manner as a typical open pit bench hook up. This paper describes the work undertaken to compare and contrast performance results obtained using a range of instrumentation including High Speed Video (HSV) filming, digital counter timing using a Hewlett Packard Universal Counter and a digital VoD measurement device. The results obtained demonstrated the practical feasibility of using the latter technology in order to obtain relatively large amounts of data in a time-efficient manner, with a precision of better than 0.5 microseconds, if required. The results also confirmed the close statistical agreement obtained between the three forms of performance measurement, therefore permitting the substitution of the VoD measurement technique for the more capital cost intensive HSV technique and the slow, sample-by-sample HP Universal Counter method. This paper describes the methodology applied and the results obtained.

Jan 1, 2004

The constructionhunnelling industry in Hong Kong has taken an upturn during the last few years due to the commencement of works to relocate the International Airport to Chek Lap Kok Island. The Airport Core Program consists of ten individual projects including roads, landfill, bridges and tunnels to build the airport and link it to the mainland of Hong Kong. Part of one of these projects is Cheung Ching Tunnel located on Tsing Yi Island. The proposed tunnel consists of a 1.6 km twin tube road tunnel through the island's central ridge, taking three lanes of traffic each way. Each tunnel is 16 m wide - (the widest road tunnel in Hong Kong) and are 10 m high. ICI Explosives (China) saw an opportunity to supply bulk explosives to the Cheung Ching tunnel and contacted ICI Australia to determine availability of a bulk system for tunnel blasting, and assist in its introduction. This paper discusses the methodology behind developing that bulk system to suit a large tunnel drill and blast operation. It also looks at the problems encountered along the way, from the development of the product to the application of the system in the tunnel and the eventual success of introducing a bulk system into a large tunnelling project.

Jan 1, 1994

By I Villalba

The need to continue the development of the Ensham mine has led to blast up to 75 m to the Eastern side of a water dam in the vicinity of Ramp 23. The water dam wall is exposed to blasting over a distance of approximately 500 m. The first decision was to determine that the existing rock pillar between the Eastern side of the water dam and the blasting operations may not be less than 75 m in order to minimise the damage that the blast could generate to the dam wall. It was also necessary to define blasting practices to minimising the blast damage to the rock properties of the dam wall and to avoid adverse effects from vibration and gases generated by the detonation on structures.For this purpose analytical designs and test blasts were conducted to assess the ground vibration attenuation within the rock pillar. From this analysis, it was concluded that the best practice to reduce the rock damage was to create a zone of fractured rock adjacent to the side of each production blast. This fractured zone would create an effective filter both for vibration and for gases generated by the blast. This zone of fractured rock was created by firing two buffer rows. In terms of pattern size and powder factor the two buffer rows were designed just to generate a fractured rock zone. To date approximately 500 m have been excavated along the eastern wall of the water dam where each production blast was preceded by a Trim blast. This practice has given good results with regard to minimising the damage generated by production blasting.

Nov 8, 2011

By X S. Li

The modern mechanical excavation machines have enough power for cutting hard rock. The ‘bottle neck’ which limits the use of machines for hard rock excavation is ‘cutting tool’. To cut hard and abrasive rock, CSIRO has been developing Super Material Abrasive Resistant Tools (SMART*CUT). SMART*CUT technology replaces the tungsten carbide (WC) tip of conventional pick with thermally stable diamond composite (TSDC) and attaches the TSDC tip to steel tool body with CSIRO worldwide patented bonding technology. This paper introduces the key features of SMART*CUT, compares its performance with conventional WC tipped tools, discusses the challenges faced by SMART*CUT and the further developments needed for successful application of SMART*CUT to mining industries.

Nov 22, 2011

By J H. Heo, J H. Park, M J. Lee

In this paper, the challenging points regarding the high temperature physical chemistry of slags to achieve the improved and stable electric arc furnace (EAF) or electric smelting furnace (ESF) technology on the way to green steel will be reviewed, and the recent experimental and modelling research will be discussed. For example, the initial melting phenomena of hot briquetted iron (HBI) and the slag formation behaviour was observed using a high-frequency induction furnace. Main component of gangue oxides in HBI was SiO2, Al2O3, and CaO in conjunction with unreduced iron oxide. To increase the dephosphorisation efficiency, the distribution ratio of phosphorus between metal and slag was calculated using FactSage™ software, version 8.2 (CRCT ThermFact, Inc., Montreal, Canada) and was compared to the measured results. The optimisation of slag chemistry is required not only for maximum dephosphorisation efficiency with good slag foamability but also for minimum slag volume with less refractory corrosion in EAF process. The slag chemistry is also one of key parameters affecting the operation efficiency in ESF in view of FeO reduction behaviour, viscosity, sulfide capacity, etc.

Jun 19, 2024

By M Revell, B Sainsbury, D Sainsbury

This paper extends the existing knowledge associated with the design and placement of prefabricated pastefill barricades through a consideration of asymmetric drive geometry and conditions. The load capacity of prefabricated barricades and their failure modes are considered in relation to abutment geology and barricade geometry that includes curvature and span and drive geometry that includes abutment angles, haunch angles and misalignment. Design charts are provided for typical barricade sizes to provide general guidance for design capacities and optimising location placement based on asymmetric drive geometry. A recent barricade failure is considered in relation to the drive geometry and the potential impact it had on the installed capacity.

Nov 29, 2022

By D J. Williams, A Shokouhi, A Naderian

Extracting alumina from bauxite involves the production of fine-grained waste known as red mud. The highly alkaline red mud is usually neutralised by applying sea water, thickened to between 25% and 30% solids by mass, before disposal to a Tailing Storage Facility (TSF). Hydraulic sorting, settling, self-weight consolidation, and desiccation are the processes contributing to the overall volume change of the red mud after deposition. Investigating the effect of these processes on the volume change behaviour of the fine-grained red mud is an important step in the estimation of the required storage volume of the storage facilities. This paper presents the results of a series of laboratory consolidation tests in a slurry consolidometer, and comparisons are made with field testing and observations.CITATION:Shokouhi, A, Naderian, A and Williams, D J, 2018. Assessing the volume change behaviour of red mud through laboratory and field testing, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 309–316 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By G Chitumbura

Raise boring is a critical aspect of mining at Xstrata Copper’s Mount Isa Copper Operations (MICO). MICO’s internal raise boring department regularly develops ventilation rises, orepasses and stope cut-off rises and reams approximately 2500 m per annum. Developed, trialled and implemented as standard practice over the past two years, procedural changes in constructing the raise bore machine’s foundations have significantly reduced operator exposure to raise boring’s inherent risks of working around open holes and manual handling. An additional cost benefit of this newly-adopted procedure is derived from reducing the likelihood of damaging the machine while de-rigging.When conforming to standard industry raise boring practices, exposure to an open hole begins when the reamer breaks through the concrete pad and ends when it is removed from the hole – a process which, depending on the size of the hole and the raise boring machine, can take up to three days to complete. Although wearing fall restraint equipment, operators working on and around the raise bore machine during de-rigging are continually exposed to the risk of falling from heights. In contrast, MICO’s newly-developed and successfully-implemented presink raise boring system reduces this exposure to a maximum of four hours, regardless of hole size. Exposure to manual handling hazards is also substantially reduced as the presink procedure eliminates manual placement of a 100 kg drill bit under the machine to commence pilot-hole drilling. Outcomes of implementing the presink System at MICO have been so beneficial that it is now standard procedure for all reaming in excess of 1 m diameters.

Mar 21, 2011

By G R. Ballantyne, G Lane

Dry milling circuits that include high pressure grinding rolls (HPGR) or vertical roller mills (VRM) and air classification have replaced dry ball milling in cement production, but how do they compare to wet milling and classification circuits in mineral processing plants? Two case studies are presented that compare the energy efficiency, wear, liberation and capital cost of dry and wet milling circuits. In both case studies the VRM and HPGR consume half the energy of a wet tumbling mill for the same duty. However, the dry classification system tends to significantly erode the energy benefits. A number of improvement opportunities are presented that have the potential to improve the energy and capital efficiency of dry milling circuits. These improvement opportunities focus on the dry classification system that consumes significant energy in heating and fan power requirements and requires a large proportion of the footprint.

Aug 24, 2022

By J O. Watson, V S. Vutukuri

This paper presents results of an investigation on acoustic emission characteristics of granite, sandstone and rock-like material in the unconfined compression and tensile tests. Both the acoustic emission signature and stress-stain curve are analysed in the experiments.The experimental results show that different acoustic emission characteristics are observed at different stress and deformation stages in unconfined compression and tensile testing. Extensive and unstable acoustic emission changes may be interpreted as indicating failure of the rock.

Jan 1, 1999