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By R Kroukamp, G Rech

CRONIMET Australia in cooperation with Speciality Metals International, the mining lease holder of the Mt Carbine Tungsten mine, have demonstrated the preconcentration and processing of large (>12 million tonnes) tailings and mine waste dumps on site in far north Queensland. The first stage of this project has proven the economic viability of preconcentration using sensor-based particle sorting whilst ensuring high recovery of industry critical tungsten minerals – wolframite and scheelite. Sensor-based sorting technology have enabled the production of a sorter product to feed the existing wet gravity plant ensuring higher recoveries and increasing concentrate production. Processing of 1,000 tonne low grade samples using the TOMRA x-ray transmission (XRT) ore sorter installed on site, has reduced the volume of material entering the downstream wet processing plant by up to 60%. The sorted 10-25mm size range produced the highest upgrade ratio (product/feed) of 24:1 and achieved sorter concentrate grade of 1.52% WO3, sorter waste grades below 0.014% WO3 and metal recoveries of up to 93.4%. The appropriately sized, barren sorter waste material is also sold as aggregate and other quarrying products and thus adding to the overall economic benefit of the project. The utilisation of the sorting technology on site has produced an economically viable project, significantly reduced capital cost, and reduced the time to market of the final tungsten concentrate. The next phase of the project includes design and installation of a larger two sorter plant capable of over 150t/h feedrate.

Nov 10, 2020

By R Barritt, P Scott, K Albano

Successful closure of tailings storage facilities (TSFs) is an environmental issue faced globally by metalliferous mines. During the initial feasibility and design phase of the mine life importance is placed on the physical stability of above ground TSFs, largely driven by legislative requirements, whilst closure planning is often a secondary consideration. However, as the landform is further developed and constructed attention must be paid to regularly revisit the original closure plan and update it to achieve the best (sustainable) possible outcome for both the environment and stakeholders. A mine in northern Queensland is in the process of developing a closure strategy at their TSF. Appropriate closure measures for the TSF are required to mitigate the impact of any seepage emanating from the TSF on the groundwater and surface water receptors. O’Kane Consultants Pty Ltd (OKC) have provided the mine assistance with the development of a TSF cover system design in order to appropriately manage tailings during operations and to prepare for the facilities’ closure. OKC has collected data since 2007 from cover system field trials located on the TSF. To enhance engineering judgement in the design of future cover systems, calibration of soil-plant-atmosphere numerical models to field data (referred as ‘field response modelling’) were completed. Calibrated model inputs can be used to provide insight into long-term cover system performance as well as a tool for design of the final landform.Following a site investigation, materials characterisation and numerical modelling program various cover system alternatives were developed. Two of the preferred cover system alternatives referred to as Test Plot #1 (TP#1) and Test Plot #2 (TP#2) (Figure 1), were constructed at the site and instrumented. Monitoring instrumentation comprised several nests of in situ volumetric water content and thermal conductivity sensors to measure changes in water content, temperature and matric suction within the cover system materials and underlying tailings waste. Run-off collection buckets and a fully-automated meteorological station were also installed. CITATION:Barritt, R, Albano, K and Scott, P, 2016. Findings and conclusions following ‘long-term’ cover system monitoring – refinement of the conceptual design for tailings storage facility closure, in Proceedings Life-of-Mine 2016 Conference , pp 85–88 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By S C. Barrie

St BarbaraÆs Marvel Loch operations have successfully used longhole open stoping as the primary mining method for a number of years. A transition to Core and Shell mining was implemented in 2009 to recover substantial ore grade resources remaining in sill and rib pillars. The transition to core and shell for the Exhibition lode required continuous waste filling of created voids and thus the removal of the crown pillar at the base of the Exhibition pit by blasting. Access to the top of pillar was denied as the pit was partially rock filled with waste rock from underground development.Beyond the technical challenges of the blasting project, a simple and transparent risk management process was developed to ensure appropriate controls and mitigating strategies were in place to minimise risk to personnel during the pillar removal process.Although failure of the crown pillar was anticipated but with the actual timing unknown, on 25 December 2011 the crown pillar yielded during normal mine operations. Engineered and isolation controls in place at the time were of a sufficiently high standard to ensure limited exposure of the underground workforce and minimal damage to mine infrastructure. Successful risk management through implementation of appropriate controls during the project lifecycle of two years and three months proved to be fundamental to the safe removal of the crown pillar.CITATION:Barrie, S C, 2012. Successful risk management through project life cycle for removal of the crown pillar at the Marvel Loch Underground Mine, in Proceedings International Mine Management 2012, pp 125-134 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 20, 2012

By C Laming, S Staude, D Hammond, S Sheppard, J Griffith, S Stanfield, S Marriott

Long Operations is located on the eastern slope of the Kambalda Dome in Western Australia. Kambalda hosts nickel deposits that are modelled to have formed from an exsolving sulfide melt from a parental komatiite melt. The nickel deposit model predicts a stratigraphical relationship where massive Fe-Ni-Cu-sulfides are deposited in troughs at the base of komatiite channels. The basal contact of the sulfides is generally tholeiitic basalt. The Kambalda geological sequence form a dome structure with a granodioritic core and have undergone tectonic and metamorphic overprinting, resulting in the formation of upper greenschist to lower amphibolite-facies units.On the basalt-ultramafic contact, within the Long Operations, there are two separate channels hosting seven different orebodies. The Moran orebody is the most undisturbed orebody at Long Operations, with many primary magmatic textures preserved, making it ideal for studies to improve the existing nickel sulfide formation model. Detailed exploration and production infill drilling and systematic sampling indicates consistent nickel tenor variations over the entire Moran orebody. This was also observed in other deposits in Western Australia and was explained as metamorphic variations. Similar variations are observed with some trace elements that cannot be explained by metamorphic overprint but with gravitational segregation in the liquid sulfide. Other more complex trace element patterns (eg Cr) require additional explanations and are partly originated from incorporation of underlain basalt and sediment and partly from gravitational segregation.From a mining perspective, the Moran orebody can be used as an example of modern high-speed mining, but at the same time preserving samples for the future and allowing knowledge from the geological context and geochemical signatures to improve future exploration.CITATION:Staude, S, Marriott, S, Griffith, J, Laming, C, Hammond, D, Stanfield, S and Sheppard, S, 2014. Improvement of existing ore-forming models due to systematic sampling during mining – an example from Kambalda, Western Australia, in Proceedings Ninth International Mining Geology Conference 2014 , pp 341–348 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By A Simmons, J Chan, A Li, Q Gu, D M. Brett

The paper presents an example of field density achievements using thin layer deposition and solar drying and compares this with compaction data from laboratory testing and field trials of mechanical densification processes.

Jul 1, 2021

By M Brady, O Salisbury, C Claassen, B Beamish, H Baxter

Monitoring for signs of elevated spontaneous combustion in the active goaf behind the longwall face is crucial for early intervention of any potential heating incidents. Typically, trigger action response plans (TARPs) are established at the start of longwall mining and often are only reviewed when triggers are activated frequently and become ‘nuisance alarms’, or in the worst case scenario after a heating event. Narrabri Mine has adopted a proactive approach of reviewing the longwall active goaf spontaneous combustion monitoring TARP at the commencement of each longwall block and prior to reaching a known ‘mylonite zone’ of crushed coal, which is associated with increased coal oxidation. The review is based on information recorded from the monitoring data of the previous longwall blocks as well as interpretation of relevant spontaneous combustion propensity results for the coal. This has resulted in the mine implementing a zoned TARP approach for each longwall block covering both the longwall retreat through normal undisturbed coal and the zone where the goaf is influenced by the increased coal oxidation associated with the mylonite coal. The consequence of this approach is that it has removed the issue of having nuisance triggers being activated during mining through a known increased oxidation zone, while maintaining a high awareness of indicators of spontaneous combustion.CITATION:Baxter, H, Claassen, C, Salisbury, O, Brady, M and Beamish, B, 2015. Implementation of a zoned trigger action response plan associated with changing mine conditions at Narrabri Mine, in Proceedings The Australian Mine Ventilation Conference, pp 113–120 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By L Bergin, D J. Williams, S Islam, T A. Vangsness

The flooding of open strip coal mines in the Bowen Basin and Hunter Valley Coalfields of Eastern Australia has the potential to soften the spoil and floor materials to produce “mud”. This mud can act as a slip plane or weak zone when spoil is dumped into it, resulting in geotechnical instabilities. Once mud has formed, typical handling techniques include its costly removal by mechanical means, or its isolation and capping.There are little data available on the moisture state and shear strength of the capped mud. To investigate the effectiveness of isolation and capping, research has been conducted using a large slurry consolidometer (150 mm in diameter by up to 410 mm in height) to simulate capping in situ. Once consolidated, the mud was subjected to shear strength testing in a direct shear box measuring 60 mm by 60 mm by about 20 mm high. The shear strength of the consolidated mud was compared to that of competent, fresh spoil, a mixture of spoil and mud, and to completely degraded spoil (mud alone).These results have been used as inputs in stability calculations using the commercial computer program Slide 7.0, which demonstrates the strong influence of consolidation of the mud on overall low wall slope stability. The results provide insight into the design and construction of capping to isolate in-pit mud.CITATION:Vangsness, T A, Williams, D J, Islam, S, Smith, A and Bergin, L, 2018. Consolidation and shear strength testing and stability analysis of coal mine spoil degraded to mud, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 97–109 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By Okabe K

Development in the theory and practice of hearth drainage is reviewed. Difficulties in the hearth drainage were re- newed during late sixties and early seventies when the size of a blast furnace and the top pressure were increased to result in the increase in tapping rate. Hearth drainage was improved first by in- creased number of tapping and then decreased tapping rate as it was predicted by theoretical studies. State of the coke bed in the hearth, e.g., 'floating' or 'sitting-on' the hearth bottom, is discussed in relation with influential factors on it and its influence on the furnace operation. The 'sitting-on' coke bed is to be aimed at for the consistent furnace working and for the lower rate of erosion of the hearth refractory. As the continuous tapping became standard prac- tice in large blast furnaces, the interest in the basic research renewed. Prospect of the further research including mathematical modelling of the hearth drainage is discussed.

Jan 1, 1981

By S Zummar, A Van den Bulck, T De Staercke, T Van Rompaey

An increase of 22 per cent in lead usage is expected in the European Union by 2050. During lead refining, the Harris process is a critical step in which a salt melt is used to remove arsenic, tin and antimony. During this process, the caustic salt melt absorbs these impurities, requiring regular evacuation before saturation. Current metallurgical practices for: 1) determining the end point of the lead alloy involve time-consuming sampling and offline analysis, and 2) determining the end point of the caustic salt melt are based on subjective visual observations by the operator. In the context of Industry 4.0 concept, automating these processes becomes desirable, as smart sensors systematically collect real-time data in an unbiased manner. This research focuses on monitoring the Harris refining process using objective methodologies. Two different methodologies are investigated. The first methodology focuses on electrical conductivity changes of the caustic salt melt as function of Sb content. For this study, synthetic and industrial samples are used. A lab-scale electrical conductivity set-up was built to accommodate the aggressiveness of the salt melt. Initial findings suggest a promising relationship between electrical conductivity and Sb content in the caustic salt melt. Although the results are preliminary, the study provides valuable insights by enabling real-time measurements. The second methodology focuses on measuring the electromotive force (EMF) in lead doped with Sb at pilot-scale. Multiple probes are reevaluated for their effectiveness in Sb measurement. Ultimately, a partially stabilised MgO probe with Ni as a reference, without cardboard and copper protection caps, yields promising results. A correlation between EMF and Sb content is observed. However, repeatability issues arise due to possible wire interference at low temperatures. The results underscore the potential of advanced measurement techniques in optimising lead alloy production within the context of Industry 4.0.

Aug 21, 2024

By G de Jong, W Sunyoto, M Cloos

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Ertsberg mining district is a 100 km2 area in the highlands of Papua, Indonesia. The district hosts mineralised and barren, outcropping and hidden porphyry and equigranular intrusions. There are at least six major (100+ m wide) porphyry intrusions identified from surface and underground mapping and drill cores. These are the Grasberg Igneous Complex (GIC), Karume porphyry, Lembah Tembaga porphyry, Ertsberg Stockwork Zone porphyry, Kay intrusion and the Wanagon intrusion. Recent deep drilling adjacent to the GIC identified a new hidden porphyry at depth, the Gajah Tidur (Sleeping Elephant), which extends south-west beneath the Kucing Liar skarn. Other named small porphyry dykes and plugs in the district include the West Grasberg, North Grasberg, Idenberg, South East and Zaagkam intrusions. The largest equigranular intrusion is the multiphase Ertsberg diorite.Igneous activities occurred in a relatively short span (<1 million years) from about 3.4 Ma to 2.7 Ma ago, based on U-Pb zircon dating. The various intrusions in the district related to ore mineralisation are high K and appear to have been derived from the same parental chamber, based on similar whole rock rare earth element patterns. Radiogenic Nd- and Sr-isotopic variations indicate that there were multiple recharge events into the parental chamber.The larger intrusions and all economic mineralisation occur in a 4 km wide zone that parallels the N60W-trending axis of the Yellow Valley Syncline (YVS), one of the large folds generated during collisional tectonism. Intrusion pathways at ~3 Ma were localised into dilatational areas in a late and/or post-collisional NW-trending, left-lateral strike-slip zone with Riedel shear offsets between the major fault zones. An early phase of lower K magmatism produced small intrusions in the south-west limb of the YVS.CITATION:de Jong, G, Sunyoto, W and Cloos, M, 2015. Composition, lithochemistry and radiogenic isotopes of porphyritic and equigranular intrusions in the Ertsberg mining district, Papua, Indonesia, in Proceedings PACRIM 2015 Congress, pp 347–356 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By P Dare-Bryan

Many mines have an interest in improving fragmentation at their sublevel caving operations in order to produce better ore recovery, lower dilution and less overbreak. The primary requirement for the extraction phase is to understand and optimise the flow of the fragmented rock in the rings including interactions with the caved material. Rock fragment formation is critically controlled by the blasting phase and can potentially be improved by optimising the dynamic energy distribution throughout the ring through the crafting of explosive charging, priming position and initiation timing. The modelling of fragmentation and damage due to explosive loading of complete rings is inherently and irrevocably a three dimensional problem that is difficult to address. We have therefore initially utilised an analytical code to predict vector peak particle velocities and energies that are restricted to the plane of a ring. Dynamic energy distributions based on common timing and priming practice have been compared with other possibilities using conventional pyrotechnic detonators as well as initiation designs based on accurate electronic detonators. The energy distribution can be quite subtly tailored to increase energy in appropriate regions or to decrease energy in the brow region for example to potentially reduce instability and the probability of misfires. We have also recently developed the capability to efficiently model particle flow using four-sided polygonal elements. Despite the 2D limitations of such a model this results in more realistic fragment interaction and stacking than can be achieved using conventional rigid circular elements. Modelling of a typical sublevel caving ring utilising these elements activated by the correct dynamics offers considerable potential for understanding the influence of the blasting energetics and timing on the complex flow and extraction process.

Jan 1, 2005

By R Daiyan, G Burge, M Haider Ali Khan

Australia’s mineral and metal exports have a substantial carbon footprint, twice that of its domestic emissions, mainly due to fossil-fuel-dependent downstream processes like processing into secondary metals and their transport. The country’s vast renewable energy and low-carbon hydrogen potential offer a promising alternative to mitigate this impact. These resources can be leveraged to displace fossil fuel use and become embedded into the metals value chain. Ultimately, it will yield ‘Green Metals’ that can be scaled to reduce the environmental footprint and provide an avenue for Australia’s vast green resources to be embedded (incorporated during production and supply) in green metals that can be exported. One potential green metal is copper, which is in great demand and likely to drive global decarbonisation through renewable electrification due to its role as an energy conductor. Given that Australia is a large producer and exporter of copper, this paper provides a techno-economic model of the copper value and applies it to Queensland (a hub of Australia’s copper production) as a case study. The results show that under incumbent hydrogen (A$8/kg) and renewable energy costs, the cost of green copper would be A$9704/t (~10 per cent higher than current copper costs). Further analysis revealed that the cost of hydrogen is a major cost driver; therefore, if the cost of hydrogen can be reduced to A$2/kg (a 2030 target of the Australian government), the cost of green copper would become competitive. Furthermore, if a carbon pricing regime ($54–79/kgCO2) is introduced, green copper would become competitive at a hydrogen cost of A$3/kg. Altogether, these findings provide insights for a future green copper export opportunity in Australia. Additionally, as the next step, the model can be extended to include other metals and released as an open-source resource for assessing global green metal opportunities.

Sep 1, 2024

By E Philippa, J Vitanza, C Hawtin, B Miller

B Miller , E Philippa , C Hawtin and J Vitanza

Mar 22, 2022

By B Wentzinger, Y Keulemans

This paper presents the results of a field study designed to assess the impact of vane rotation speed on the estimated undrained strength for two Australian bauxite tailings storage facilities. The vane test results are assessed against cone penetration and dissipation tests results to identify if partial drainage may be an issue. An innovative tool capable of measuring pore pressures during vane shear testing, the Piezovane™, is introduced as an improvement over the standard field vane to assess drainage conditions in real-time.

Jul 1, 2021

By J Dwyer, G Turner, D Pridmore, M Urosevic

Due to their ability to produce high-resolution images of the subsurface to great depths, seismic surveys provide critical inputs to almost all oil and gas exploration projects. However, with some notable exceptions, seismic surveys have rarely been used in mineral exploration. In the past, this was due to both technical and financial reasons. Significant developments on both fronts mean that seismic surveys can now offer substantial benefits to mineral exploration and mining, and surveys conducted for exploration can provide important data sets for mine planning over the life of a mining project.We present case history data that show that seismic surveys can greatly assist with mapping the 3D distribution of lithologies and alteration and, in favourable circumstances, directly detect mineralisation in and around mineral systems. As a result of their high spatial sampling density, seismic surveys are also highly effective at mapping structures that can remain undetected or poorly characterised by drilling alone. These structures may host or provide important vectors to mineralisation. They can also be particularly important when planning shafts, raise bores, declines, stopes and open pit walls. A further benefit of seismic surveys is that they can remotely provide information on geotechnical rock parameters that are used for rippability, slope stability, blasting and ground support.CITATION:Turner, G, Urosevic, M, Pridmore, D and Dwyer, J, 2015. Exploration and mining unified through seismic imaging, in Proceedings Third International Future Mining Conference, pp 117–122 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

Development of a global failure criterion for rocks has been a desired goal in rock mechanics. Due to variations in factors affecting rock specifications and their mechanical properties, proposing a single failure criterion suitable for all rock types has proven to be unachievable. The theoretical failure criteria do not fit the real data correctly. Amongst empirical criteria, the Bieniawski criterion has demonstrated an acceptable agreement with laboratory generated data. It has been experienced that the ability to estimate rock strength via the modified form of this criterion is significantly improved. Based on the modified Bieniawski criterion and using VB.net, an associated Microsoft Windows program named 'RAMOCE' has been developed. The inputs of RAMOCE can be triaxial compressive strength data, Bieniawski parameters of a specific rock or the type of given rock. Based on input data, potential outputs of the program are Bieniawski's rock parameters, sensitivity analysis of the effective parameters, rock failure prediction and defining the type of given rock.

Nov 25, 2010

By R Zhang, X Huang, M Zhou, X Lv, C Bai

Iron ore sinter accounts for a large proportion of blast furnace ferrous burden in Chinese steel mills. Depleting high-grade iron ore resources and spreading complexity of iron ores in mineralogy and morphology have made it more difficult to utilise iron ores efficiently and economically. In this paper, the physical properties of iron ore particles were characterised using mechanical sieving, laser sizing and gas adsorption. From those measurements, two physical indices (fractal dimension of the particle size distribution and surface morphological factor) are defined as important variables for optimising the granulation performance of iron ores. The moisture capacity and the contact angle of iron ore particles with water were also measured to determine the strategy of water-feed in the granulation process. It can be concluded from the experimental results that an increase in the fractal dimension of the iron ore particles will lead to a better granulation performance, while an increase in moisture capacity with a range of 12.8 ~ 14.8 per cent would increase the optimum water content where the granule packed bed achieves its best permeability. Furthermore, the optimum permeability varies inversely with the moisture capacity of the sinter mixture.CITATION:Huang, X, Lv, X, Zhang, R, Bai, C and Zhou, M, 2013. Iron ore characteristics and their application in optimising the granulation process, in Proceedings Iron Ore 2013 , pp 261-268 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By W Midgley, M Torok, I Canbulat, J Katupitiya, S Saydam, S Akdag

The green energy transition is expected to require a range of valuable minerals, which could be supplied through deep-sea polymetallic nodule mining. Deep-sea polymetallic nodules are mineral deposits with a composition well suited to produce lithium batteries, which are expected to be a necessary energy storage solution (Diouf and Pode, 2015; Paulikas et al, 2020) for the energy transition. By 2050 the annual demand for both cobalt and lithium is estimated to increase by around 450 per cent from 2018 levels (Hund et al, 2023), with the annual demand for nickel being greater than 2 million tons, and copper greater than 1 million tons. Polymetallic nodule mining is well positioned to provide these minerals in the near future. An intricate and comparatively unexplored ecosystem thrives within and surrounding the nodule fields (Smith et al, 2008). Deep-sea mining operations have the potential to disrupt and permanently damage this ecosystem through introduced pollution, artificial noise and light, and habitat destruction. Hence, there is a pressing need for new engineering and scientific endeavours to focus on developing new technologies to reduce any environmental impact from mining.

Sep 1, 2024

The C.S.A. copper lead zinc mine, located seven miles north of Cobar in Central Western New South Wales, is the largest known mineral occurrence in the Cobar Mining Field. Hosted by the steeply west dipping, west facing sediments of the Cobar Group, the generally discordant orebodies occur within a strike width of 600 ft and an overall strike length of 1200 ft. They comprise lenticular steeply north pitching and east dipping zones of sulphide mineralisation which range in composition from massive pyrite-sphalerite-pyrrhotite--galena to less massive pyrite- pyrrhotite-chalcopyrite varieties. The thinly bedded siltstones, shales and graywackes hosting the mineralisation appear to have derived many of their constituents from volcanic sourcesä They have been metamorphosed to the greenschist facies of regional metamorphism. At least two stages of deformation and folding have occurred. The first stage folded the rocks on a south pitching fold axis into their present configuration, and super- imposed a strong axial plane cleavage which subsequently guided the emplacement of the mineralisation. The second stage of deformation is considered to have controlled the zonal distrib- ution of the orebodies and the appropriate fold axis appears to coincide with the long axis of the orebodies.

Jan 1, 1969

By F Hungerford

"In-seam drilling has been undertaken for the past 30 years for gas drainage to reduce the risk ofoutburst and lower the concentrations of seam gas in the underground ventilation. The drillingpractices have reflected the standards of the times and have evolved with the development oftechnology and equipment and the needs to provide a safe environment underground. Earlypractice was to adapt equipment from other fields, but with changing emphasis, research anddevelopment by the coal industry has created specifi c equipment, technology and practices toaccurately place in-seam boreholes to provide efficient and effective gas drainage."

Jun 1, 2012