Search Documents

By A Sinuhaji, R Poedjono, G Flumerfelt

PT Freeport Indonesia is currently building the DOZ mine. It is a 25 000 tonne/day block caving operation which is scheduled to reach designed production levels by the fourth quarter of 2002. This paper describes some of the issues and challenges faced by the operation when introducing a new undercut method part way through the project. Advantages and disadvantages are discussed as well as the expected benefits of the new method.

Jan 1, 2002

By M Simanjuntak, A M. Supomo

PT Freeport IndonesiaÆs copper/gold operation disposes of approximately 222 000 dry metric tonnes of tailings per day via two thickeners. Reduction of the flocculant dosage rates in each of the tailing thickeners has been achieved with the installation of Clarometers«, modifications to the existing operating DCS control strategy and a change in plant flocculant. This has reduced the flocculant consumption rate in the last twelve months by approximately 20 per cent. It has also highlighted the disparity in the settling rates of the two thickeners. Collaborative efforts between Cytec technical site engineers and Freeport operational personnel have made possible the overall gains achieved in the tailings thickener optimisation.

Jan 1, 2003

By G McLeay, T Moran

Long Shaft has traditionally been seen as one of the most challenging mines in the Kambalda area with operations having been suspended by the previous owners in 1999. When mining recommenced in October 2002, the current owners (Lightning Nickel) decided that a different approach was required for mining operations in such an aggressive geotechnical environment. This paper describes how Lightning Nickel has successfully and safely operated the Long Shaft complex on a traditional mining approach, which encompasses the key learnings of the previous owners.

Jan 1, 2005

By X Hu, J Björkvall, L Sundqvist Ökvist

The metal production industry is a significant contributor to global CO2 emissions due to the use of fossil fuels such as coal and coke. To mitigate these emissions and meet climate goals, innovative and sustainable technologies are required. Molten salt electrolysis is a promising technology that directly produces metals from their precursor sulfides or oxides using electricity. When combined with renewable electricity and an inert anode, the electrolysis process can be carbon neutral. This paper presents the results of two pilot-scale studies on the electrolytic reduction of metal oxides and sulfides in molten salts. The first study focuses on the electrolytic reduction of chalcopyrite in molten NaCl-KCl salt. The results demonstrate that in situ separation of copper, iron, and sulfur is possible, enabling the extraction of all valuable elements without CO2 emissions. Furthermore, the findings underscore the capability to eliminate impurities like zinc, antimony, arsenic, and mercury from the electrolysis product. The second study investigates the electrolytic reduction of pure/synthetic chemicals of wüstite, hematite, and magnetite, as well as a magnetite-type iron ore in molten NaOH salt. The findings reveal a stepwise reduction of iron oxides from high valence to low valence, ultimately leading to the production of metallic iron electrolytically. Notably, this study underscores the challenges associated with the selection of an economically viable and durable inert anode material for efficient oxygen generation. These results indicate that molten salt electrolysis provides a sustainable and green route for base metal production. The use of this technology has the potential to significantly reduce CO2 emissions in the metal production industry, contributing to achieving climate goals.

Jun 19, 2024

By T. Baker

The Eloise Cu-Au deposit is 60 km SE of Cloncurry in NW Queensland and has a current indicated reserve of 3.2 Mt @ 5.8 per cent Cu, 1.5gA Au and I9g/t Ag. It is hosted by metasediments and metabasic rocks that underwent amphibolite facies metamorphism at 550-600¦C and less than 3.5 kb. Peak metamorphism coincided with the regional D2 event which produced an S2 foliation with north-south strike and variable sub-vertical to steep east or west dip. The deposit is associated with several major shear zones parallel to the S2 foliation. The lodes form part of a large alteration system that is localised by the retrograde shear zones. Homblende-biotite-quartz with minor sulphides occur early in the alteration paragenesis which is overprinted by chlorite-muscovite-pyrrhotite-chalcopyrite ¦calcite+¦nagnetite. The later assemblage replaces the earlier Fe-K alteration as well as Fe-rich metamorphic assemblages such as homblende, biotite and staurolite indicating a post peak metamorphism timing for ore formation. Although replacive textures are the most common, the alteration can display open space infill and brecciation as well as durchbewegung and mylonite textures indicating that mineralisation occurred during ongoing ductile deformation. All these features are crosscut by a later brittle phase of calcite-chlorite-quartz¦pyrite alteration.

Jan 1, 1994

By H Park, D J. Holland, L Wang, Y Matviychuk, Y Lee

Reuse of process water in mineral and coal flotation plants is widespread to effectively reduce freshwater consumption. However, the accumulation of the frother in the recycled process water is a growing problem as high remnant frother concentration often leads to undesirable overfrothing issues throughout the plants. Various approaches have been proposed by others to measure frother concentration, but none of them is used in flotation practice owing to the requirement of timeconsuming sample preparation steps and/or specialist training to operate and maintain. There is a pressing need for the development of a simple and fast frother concentration measuring technique to avoid overfrothing issues and to optimise the flotation process. The present paper presents two promising approaches to measuring frother concentration online. The first approach measures the concentration of alcohol type frothers based on the host-guest interactions between frother molecules and a formulated liquid. This method is simple and fast as it only requires mixing the formulated liquid with the water sample for up to one minute. The potential of this approach was demonstrated by determination of the residual MIBC concentrations at different locations across a coal flotation plant. The second approach measures frother concentration using a solid-phase extraction (SPE) process and a cryogen-free benchtop NMR spectrometer. Using this approach, both alcohol type and polyglycol type frother solutions can be analysed for concentration determination within 30 minutes. It has also been demonstrated that the concentration of individual frothers in a frother blend (ie MIBC and PPG425 in water) can be accurately analysed even in the presence of background chemicals. This technique has otential for real-time measurement of frother concentration as the whole process can be fully automated.

Aug 24, 2022

By A Karrech, A Hasan

This paper presents the numerical simulation of mine backfilling in underground stopes using three-dimensional discrete element modelling (DEM). The simulation predicts the forces exerted at the stope base and barricade with respect to time under free drained conditions. The results of the numerical simulation are validated using basic analytical solutions and advanced experimental tests involving a geotechnical centrifuge system. Overall, a good agreement between the present numerical simulations and the existing experimental and analytical results was found. The present model suggests that DEM is a promising computational tool to predict barricade pressure in underground mine stopes.CITATION:Hasan, A and Karrech, A, 2014. Simulating mine backfill in a fully drained condition using discrete element modelling, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 117–124 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By M Chiquito, R Castedo, P Segarra, L M. López, J A. Sanchidrián, J Navarro

The aim of this work is to assess the performance of different constructive solutions against explosions on the strength of masonry walls. The solutions tested, namely an external metal mesh, a glass fibre film on the external face of the wall and a basalt fibre film located on the inner face of the wall, have low to medium cost and are originally designed for other purposes, like seismic protection. Four cubic boxes 3 × 3 × 3 m were built using each of the solutions and typical masonry blocks. In the tests, a spherical plastic explosive initiated in the centre was placed at scaled distance of 2.9 m/kg1/3, so that moderate damage would be caused on the wall. In order to assess the performance of the explosive, pressure gauges were placed at the wall and at different distances from the explosion. Additionally, vibrations were monitored with seismographs in the far field and a high-speed camera was used to estimate the shock wave velocity during the tests. The resulting damage has been evaluated on 13 points of the external wall of each box using a rebound hammer. Damage maps have been drawn for each wall based on these measurements and damage has been assessed inside the box considering the fragments mass launched during the test. The use of external metal mess leads to a decrease of 34 per cent on damage of the external wall and 38 per cent reduction of spalling. The use of a film in the inner wall provides a strong reduction on spalling.CITATION:López, L M, Segarra, P, Castedo, R, Sanchidrián, J A, Navarro, J, Santos, A P and Chiquito, M, 2015. Performance of different constructive solutions against explosions in full-scale masonry walls, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 819–824 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

The Mammoth Mine is located some five kilometres from the town of Gunpowder which is approximately 120 km north-west of Mount Isa in Queensland.

Jan 1, 1993

By D Mee

The Western Mining site at Olympic Dam, near the community of Roxby Downs in South Australia is one of the largest orebodies of its type in the world. It contains known reserves of over 10.6 M tonne of copper, with economic secondary metals including uranium, silver and gold. In 1996, an expansion project was commenced to increase mine production approximately threefold, to produce 200 000 tonnes pa of copper, 4600 kg pa of uranium oxide, 3600 kg pa of gold and 50 000 kg pa of silver. This expansion included both underground mining and surface processing investment. Because of the scale of operations, it was decided that ore should be transported underground by a railway system. In July 1997, ALSTOM Automation and Control Limited (then Cegelec Australia Limited), was awarded the contract to deliver a control system to manage and automate the rail haulage system for Western MiningÆs Olympic Dam Mine, as part of this major upgrade and extension project. This paper explains the overall design and the approach taken to implement route selection, route locking, train interlocking and track topology using normal industrial control equipment such as Programmable Logic Controllers. Included is a discussion of how this automation has improved the productivity of the haulage system by more than 15 per cent.

Jan 1, 2000

Although mining, particularly of gold and coal, played a significant role in the development of New Zealand, from the time of the spectacular gold rushes of the 1860s its economic importance to the country as a whole has decreased substantially since that time. Gold, coal and non-metallic agricultural and industrial minerals have been found in economically significant quantities, however, the search for base metals has not been successful.

Jan 1, 1982

By B D. Sowerby, N G. Cutmore

Improved process control can be achieved through the accurate and reliable on-line measurement of critical process parameters in real time. Over the past few decades on-line analysis techniques have been developed and applied in the mineral and energy industries for the measurement of process stream composition, mineralogy, particle size and flow rates. This has led to increased throughput and product quality while reducing processing costs and minimising emissions. The support of a sustainable mineral processing industry will require the further development of on-line analysis and control technologies. The application of developments in instrumentation combined with improved control strategies will lead to improvements in process efficiency resulting in large economic benefits to the industry, reduced energy usage and lower process emissions. There is a clear convergence of interests in being able to better measure and control minerals processing in terms of the triple bottom line of economic, social and environmental impacts. Technology is increasingly becoming available enabling measurement across the entire spectrum of minerals processing from mining to hydrometallurgy and pyrometallurgy. CSIRO is developing a range of these new technologies. A number of these developments are discussed in the present paper, namely: on-line particle size analysis and acoustic emission methods to enhance the control and optimisation of grinding circuits; on-line mineralogy of dry powders and slurries; on-line bulk elemental analysers for application on conveyor belts and in smelters; and the development of new sensing technologies for sorting base metal ores.

Jan 1, 2002

By Wyborn L. A I, Idnurm M, Hinman M. C

Comparison of the Proterozoic Apparent Polar Wander Path (APWP) for Australia with the corresponding geology of northern Australia suggests that a number of discrete interplate tectonic events, manifested on the APWP as bends or inflections, may have controlled sedimentary basin evolution, ore fluid production and the timing of mineralisation. Similar features in the Phanerozoic APWP for the North American plate appear to correlate with major orogenic events, basin deformation, movement and 'entrapment' of hydrocarbons and minerals. Interplate tectonic events cause intraplate deformation which in turn controls the subsidence/uplift and sedimentation histories of the basins. Interplate events are thus responsible for creating, deforming and destroying sedimentary basins and the associated petroleum and mineral systems. The basins of northern Australia show remarkable similarities in the successions of volcanic and sedimentary deposits. Unconforrnities of regional or sometimes only local extent have been mapped between the major sedimentary sequences and it is predicted that interplate tectonic events corresponding to bends or inflections on the APWP directly reflect the processes that have produced these widespread unconformities. These processes are also likely to have controlled the geometry and character of the fluid migration pathways and hence the mineralising events. Palaeomagnetic studies of Proterozoic rocks in sedimentary basins provide a tool for predicting the timing of regional mineralisation events, particularly for low-temperature mineral systems. The techniques, when coupled with systematic regional basin analysis, using petroleum exploration techniques, may identify a number of new mineral 'plays' in northern Australia. Prominent inflections in the APWP occur at approximately 1700, 1670, 1650, 1600, 1540, and 1480 Ma. Each of these may be related to a regional compressional deformation, important mineralising event, or significant change in style and type of sedimentation. Most appear to be associated with magnetic overprints. Some of the inflections between 1400 and 540 Ma may also mark significant events in the evolution of Meso- and Neoproterozoic basins. Further work is required to correlate inflections in the APWP with alteration events in order to understand their regional significance.

Jan 1, 1994

By D Giurco

This paper presents the results from research undertaken in the CSIRO-funded Mineral Futures Collaboration Cluster on developing a future vision for the mining and minerals industry – Vision 2040 – in which the industry proactively contributes to long-term benefit for communities and the nation. Our research finds that Australia is currently experiencing mining-led prosperity due to high commodity prices, yet underlying this are challenges for maintaining market share due to lower productivity from extracting lower grade, more remote and complex ores. Whilst much focus has been on developing new technologies for finding and processing such ores, this paper assesses these activities, together with policy and market innovations in the context of needing to strengthen social, environmental and financial capital for long-term benefit. Vision 2010 sees mining activities linked to systems that are net providers of clean water, energy and ecosystem services, rather than minimising negative impacts alone; sovereign wealth funds are used to harness current prosperity for future innovation. Using a case study in lithium and comparisons to iron/steel, coal and copper – we illustrate the opportunities for new technology, policy and market innovations to link the mining and minerals sector in Australia to more sustainable patterns of production, consumption and prosperity.

Nov 22, 2011

By Chitombo GPF

The dilution of blasted ore with cemented backfill materials has been recognised as a significant factor influencing the economics of some underground metalliferous mining operations. Several mechanisms have heen identified as possible causes of fill failures. The purpose of this study was to determine the possibility of damage as the result of one mechanism, that of production blasting adjacent to bodies of cemented hydraulic fill (CHF). A vibration amplitude transfer function has been developed to model the transmission of blast vibrations from the source, through ore, across the ore to CHF interface and into the CHF mass. The model may be applied in the near field. The model has permitted estimation of vibration amplitude at a point in a CHF mass, to which damage criteria may be applied. A number of assumptions and simplifications have been made to render the problem relatively tractable. Ore and CHF material characteristics recorded by a number of authors were utilised to formulate preliminary damage estimations. A simple application of the amplitude transfer model indicated that a zone of plastically deformed CHF would be produced, and would extend to a distance of approximately 0.5 metres from the interface into the CHF. A sensitivity analysis was also conducted, that indicated that the zone of plastic deformation would be more extensive given appropriate conditions. Recommendations for further model development and future laboratory and field investigations have been made.

Jan 1, 1998

By I H. Jung, W O. Choe

Gallium (Ga)-containing compounds such as Gallium Arsenide (GaAs) and Gallium Nitride (GaN) are widely used in electronic devices due to their superior electro-optical properties and their usages increase rapidly. For the sustainable supply of Ga to electronic industry, therefore, the recycling of Gallium becomes essential. Pyrometallurgical Ga recycling process involves the complex chemical reactions between slag, matte, liquid metal, gas, refractories, etc. Therefore, the accurate thermodynamic information and phase diagram data for the oxide system containing Ga2O3 is important. In the present study, new phase diagram experiments for binary SiO2-Ga2O3 and ternary CaO-SiO2-Ga2O3 system are carried out using Differential Thermal Analysis (DTA) and quenching experiments followed by Electron Probe Micro-Analyser (EPMA) and X-Ray Diffraction (XRD) phase analysis. Based on new phase diagram data and available literature data, the thermodynamic modelling of the entire CaO-SiO2-Ga2O3 system is performed for the first time.

Jun 19, 2024

By K C. Corin, C T. O’Connor

In recent years it has been shown that the concept of using partial molar excess Gibbs energy (G̅ex) to explain the behaviour of collectors in the recovery of minerals can be usefully applied to explain flotation performance. Fundamentally this is because hydrophobicity of a mineral particle on which a collector is adsorbed may be strongly related to the fact that the alkyl chain associated with the collector behaves in the same way as any hydrocarbon would in an aqueous medium. This hydrocarbon-water system represents a classical non-ideal mixture, and such mixtures are quantified thermodynamically by determining the activity coefficient of the hydrocarbon moiety of the collector and hence its G̅ex in the mixture. It has been shown that G̅ex is a more rigorous indicator of the contributions of various alkyl groups of a collector than HLB (Corin and O’Connor, 2014) and was also able to explain aspects of froth behaviour (Harris and O’Connor, 2017) and hydrophobicity (O’Connor, 2021). The present paper is aimed at extending the above concepts in two different ways. Firstly, a study is undertaken of a range of results previously reported in which various reagents containing different alkyl groups were analysed in terms of their effect on contact angle and their performance as flotation reagents in terms of recovery. These results sustain the previous observations that there is a robust positive relationship between hydrophobicity as indicated by flotation recovery and contact angle and G̅ex of the alkyl group associated with the collector. Secondly, on the basis of the observation that increases in G̅ex are indicative of increases in the hydrophobicity of the mineral particle-collector aggregate, a study was undertaken to examine the effect of ions typical of electrolytes in water as well as the effect of the presence of alcohols and of pH on G̅ex of the collector alkyl group. In the former two instances the absence of any correlation between G̅ex and recoveries supported the proposition of the respective authors of these studies that the major effect of these electrolytes and added alcohols may be on particle–bubble attachment rather than on the hydrophobicity of the mineral/collector in the aqueous system. On the other hand, the effect of pH on G̅ex correlated reasonably well with changes reported in the literature on the effect of pH on recovery and contact angle.

Aug 24, 2022

By D W. Airey

Frictional rock bolts are widely used because of their low cost. However, they have a thin wall section that makes them prone to corrosion, and they cannot be relied on to provide long-term ground support. It is difficult to assess the capacity after the bolts have been installed as they can only be pulled out if this has been allowed for during insertion. The questions of how long can the rock bolts function effectively and the effectiveness of various surface coatings, which can have significant cost implications are, investigated in this study.A series of accelerated corrosion tests have been performed on frictional rock bolts. The rock bolts, typically 900 mm long, have been inserted into concrete cylinders produced using a styrofoam insert to create the hole for the bolt insertion. Strata rock bolts with four surface coatings have been tested: uncoated black steel, galvanised, enduro (plastic coated) and coated with a proprietary aluminium/zinc alloy. Tests have been performed on two diameters of bolts. Following insertion of the bolts, the concrete cylinders were placed in a large drum filled with saltwater and current was applied to accelerate the corrosion process. The rock bolts were then extracted at various times after the commencement of corrosion. Comparison of the insertion and extraction resistances shows that corrosion initially increases the bolt resistance and that substantial section loss is required for the bolt resistance to drop significantly.CITATION:Airey, D W, 2014. Laboratory corrosion tests of frictional rock bolts, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 257–262 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By P J. Hawke

Within the Mesa J pisolitic iron ore mine, clay is distributed unevenly throughout the deposit and often forms as pods and channels less than 10 m in width. The mine resource model, based on 50 m + 50 m spaced drilling, has been unable to accurately delineate the clay for scheduling and mining purposes. Therefore, alternative methods for mapping the clay-contaminated ore were sought. Predictive clay mapping will significantly reduce production costs at Mesa J through improved selective mining practices, more accurate scheduling, reduced wear on mining equipment and minimising the need for maintenance of haul roads and ramps. High lateral resolution electromagnetic (EM) surveying using a Geonics EM31 instrument can quickly and inexpensively delineate the extent and orientation of the clays. Preliminary results indicate that a block model based on the interpretation of the EM data can accurately predict the distribution, volume and tonnage of ore and waste material. While rip-line mapping, infill drilling, ground penetrating radar and gravity can delineate clay with various degrees of success, none were as efficient as EM31.

Jan 1, 2002

By S Hapugoda, A Edenton, M Adam, R J. Holmes, J R. Manuel, R Smyth

Lump ore is one of the key ferrous feeds used in the blast furnace ironmaking process, normally accounting for ten to 20 per cent of the blast furnace burden. Like other feeds, the characteristics of lump ore have an important impact on the stable operation and productivity of the blast furnace. Lump ore is usually assessed chemically, physically and mineralogically to establish its likely blast furnace performance. The physical characteristics of lump ore are strongly related to the chemistry, mineralogy and texture of the ore involved. In this paper, the blast furnace ironmaking process is reviewed, with particular emphasis on the key quality requirements for the ferrous burden material. A variety of key physical characteristics of lump ore measured using standard and non-standard methods are then described and subsequently correlated with the chemical and mineralogical characteristics of the ore wherever possible. Finally, the impact of these physical characteristics on blast furnace operation is assessed.

Jan 1, 2009