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By A Reid

The Late Archaean of South AustraliaÆs Gawler Craton contains significant potential for gold resources. The main targets of interest are migmatised gold style systems of which the Challenger deposit is the best known example. This deposit is one of the lower cost gold producers in Australia due to the high-grade, low-tonnage nature of the mineralisation. Structurally controlled, metamorphosed deposit styles are also possible throughout the Archaean of the Gawler Craton, including occurrences within reactivated shear zones. More typical, lower metamorphic grade orogenic gold styles are also possible within greenstone host sequences identified in the central and southern parts of the Gawler Craton.

Jan 1, 2007

By S McGregor, J Sharp, I Entezari, T Boulter

The piezocone penetration test (CPTu) is one of the primary screening tools used by the mining industry to evaluate whether tailings are susceptible to liquefaction (static or cyclic). Liquefaction analysis using the CPTu is influenced by the fines content of the soil, and most CPT screening tools empirically use the behaviour type index (Ic) to correct for fines. The issue with this approach is that such empirical relationships have been developed using data collected from natural soils and their applicability to different tailings deposits needs to be studied. In this paper, we explore the use of machine learning to develop a site-specific model to estimate fines content of tailings using gamma piezocone penetration testing (GCPTu) measurements. The results are then compared to the fines content derived from the soil behavior type index (Ic) proposed by Robertson and Wride (1998). A dataset of paired GCPTu and laboratory results were compiled and a support vector machine (SVM) algorithm was employed to calibrate a model to estimate tailings fines content from in-situ GCPTu data. We calibrated GCPTu data to geotechnical 75 μm fines content measured in the laboratory. The geotechnical fines content is the fines content as a percentage of solids. The development dataset was comprised of paired GCPTu-laboratory results collected in 2009-2019 from a mining area with predominately clay mineral and quartz sand tailings. Results show that the developed model predicts the geotechnical 75 μm fines content of the studied deposits with 7.8% error. The Ic based method estimates the fines content with 31% error. Evidently, the Ic method is not applicable to the studied tailings deposits. It is appreciated that many tailings fines do not contain clay, and that the success on this program may not be repeatable everywhere. However, the authors wish to point out that the application of site-specific machine learning algorithms may be used to significantly improve empirical geotechnical parameters.

Jul 1, 2021

Bacterial Leaching of Complex Polymetallic Sulfide Ore The work described here concerned the study on bacterial leaching of complex sulfide minerals and polymetallic ores operated in shaken flasks and small-scale columns. The bioleaching of jamesonite was not accessible. The iron extraction in pyrrhotite leaching reached 98.2 per cent after 23 days. After 26 days, the zinc extraction of marmatite reached 92.3 per cent while the iron extraction only reached 13.6 per cent. The pulp density had effect on the metal extraction of pyrrhppite and marmatite. For complex polymetallic sulfide ores, after 10 days in shaken flasks, 97.1 per cent zinc extraction was achieved. While after 60 days in small-scale column, the zinc extraction only proceeded to 7.8 per cent; By SEM and EDXA of experimental samples and their leaching residuum, the bioleaching mechanism was discussed.

Sep 13, 2010

In coal mining, geophysical techniques have an established application in determining the location of seam boundaries ahead of the face so that underground mines can be planned to avoid any geological structures that might disrupt production. Geophysics can also be used in geotechnical studies to determine the in situ properties of the rock mass and the response of the rock mass to the mining. The use of geophysical logs and microseismic monitoring in these geotechnical applications are discussed in this paper.

Jan 1, 2002

Comparison of Industrial Cyanide Destruction Processes

Sep 13, 2010

By P Landeros, D Benado, J Cornejo, A Pinochet, C Caviedes

In 2005, El Teniente mine began preconditioning the primary rock mass by hydraulic fracturing (HF). The major perceived benefits of this process are a decrease in the magnitude of the expected maximum seismic event and improved cave propagation. In addition, HF has resulted in new information on the propagation pressures of each fracture. Previous studies have attempted to relate propagation pressure to minor principal stress or confining stress.Considering the spatial continuity of propagation pressure and the significant quantity of collected data since the incorporation of the HF technique, minimum requirements for geostatistical modelling have been reached, permitting robust estimates inside the representative volume with acceptable errors (Cornejo, Muñoz and Rojas, 2012; Cornejo and Landeros, 2013). These results are then used to identify zones with higher magnitudes, which are mostly related to more complex geotechnical zones (intrusive and major faults) and caving singularities, making it possible to estimate the spatial extension of these zones.Finally, these results are integrated with other geomechanics aspects to support risk analysis of the mining plan.CITATION:Cornejo, J, Landeros, P, Benado, D, Caviedes, C and Pinochet, A, 2016. Geostatistical modelling of hydraulic fracturing pressures at El Teniente Mine, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 183–190 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By D Craw, S Clearwater, S Hammit, C Smith

Prior to rehabilitation, plant cover on quartz gravel overburden at Wangaloa coal mine was highly patchy. Stabilisation techniques have since considerably altered the condition of the main overburden yet deposits in the east and west remain largely intact. On the eastern overburden, three distinct zones of revegetation have naturally developed: Zone 1 represents a dense plant cover, Zone 2 a patchy cover and Zone 3 a sparse cover of isolated plants. Aerial photographs show much of the eastern overburden was deposited between 1940 and 1960s. Yet we found that the temporal scale of deposition did not wholly account for the differences observed in vegetation development. To investigate other influential factors, we set up 12 study plots using four replicates in each vegetation zone. The diversity and density of plants in each plot were measured to quantify the degree of vegetation development. Samples from the substrate in each plot were collected using soil cores to a depth of 10 cm. Cores were analysed for indicators of nutrient availability, metal content and physical composition. We found that substrate chemistry varied between individual study plots, but showed little difference overall along the vegetation gradient. Substrate physical differences were much greater. The ratio of coarse quartz pebbles: fines was considerably higher in Zone 3 than other zones, and within zones where plants were not growing. Bulk density also increased successively from Zone 1 - 3. We found clear evidence for the reversed stratigraphy of excavation superimposed over the time scale of deposition, and the corresponding nature of fine particles. The rate of revegetation was therefore highly dependent upon the substrate composition of the last surface deposit from the dumping truck. Our data suggests an optimum ratio exists between inert coarse material and a fine matrix for progressive natural vegetation development on mine substrates.

Jan 1, 2004

Longwall mining originated in the early 18th century in the county of Shropshire in England, where it was known as the longway method. Its name implies the extraction of the seam over a long continuous length or wall of exposed coal. Until the late 19608 and early 1970s the use of the longwall system with a few exceptions was confined to the United Kingdom and Europe. It was not until the early 19708 that the highly productive longwall faces we now know, were developed and the application of the longwall system extended to Australia, South Africa, United states of America and other parts of the world. The modern longwall face has three major components, namely: +         the machine to break and load the coal +         the face conveyor; +         and a system of roof support.   This paper reviews the development of longwall mining technology. The parameters directly influencing the production 'of a modern longwall face are considered, as are the possible constraints to the further development of the longwall system.

Jan 1, 1991

The New Technology of Enrichment of a Fine Low-Grade Tungsten from Complex Multi-Metallic Ore

Sep 13, 2010

The pressure of low commodity prices forced the design process for the second lift of Northparkes E26 Mine to adopt a continuous improvement philosophy. The emphasis was to minimise capital expenditure while still maintaining the excellent low operating costs achieved on Lift 1. Although the first block cave lift at Northparkes is the most productive underground mine in the world and is held up as a benchmark for the use of technology in mining, areas for improvement were identified. Every area was critically assessed and investigated for the possible application of new techniques and technologies. Key learnings from the construction and production phases of Lift 1 were captured, documented and used as the starting point for the Lift 2 design. This paper shows how and why the design parameters initially used onLift 1 were changed to become the current E26 Lift 2 developmentproposal. The main differences between the two block caves arehighlighted. The alternative techniques and equipment that wereconsidered are also discussed. * Originally published in the Proceedings of MassMin 2000,published by The AusIMM.

Jan 1, 2001

Development of Grindability Tests Based on Direct Measurement of Energy Nowadays, for the characterisation of the grindability different grindability indices - Bond-work index (Wi), Hardgrove Grindability Index (HGI) or Zeisel specific grindability (Wt) - are used. Generally, the grindability tests are carried out under relatively simplified circumstances, in a special dry batch mill with defined feed size material until prescribed conditions are reached at room temperature. However, in the fine- and ultra fine grinding, which is a frequent task (fly ash, tailings, alumina, etc), a fine material (<50 - 200 ¦m) is usually ground down to the few micrometers. The conventional grindability testing methods and apparatuses (Bond-, Hardgrove-, Zeisel-processes) for their determination, although, are not suitable directly to measure the grindability of such fine materials, since the maximal particle size of the feed material (0.5 - 3 mm) to be tested is much higher. One of the important goals of the research carried out in our Institute was to develop the novel grindability testing methods, which are suitable for the fine and ultra fine grinding, and additionally provide the possibility for the fast determination of the grindability. In order to realise the above aim the conventional Bond- and Hardgrove- mills were modified in order to directly measure the grinding work. In particular, the Hardgrove-mill was equipped with a simple torque-meter (load cell). The Bond-mill was rigged with a digital electric power measurer. The systematic experiments were carried out parallel in both mills using the conventional and the developed methods. Finally the results of both were compared. The measuring results have proved that the Bond-work index can be determined based on the developed methods. The new grindability testing methods were applied successfully in several industrial research tasks for the determination of the specific grinding energy and the Bond-work index. These methods can be also used in the industrial practice for the control of the grinding process.

Sep 13, 2010

By C T. Portelli

Belt conveyor transfers are the most likely location for high wear rates and failures. Belt transfers are necessary to change the direction of conveyed material and will remain a part of belt conveyor systems into the future. Burden being accelerated due to fall and changes in direction from one system to the next, prevents steady state flow which introduces component fatigue. The conveyor belt is considered the greatest cost item over the life of a belt conveyor system and consumes considerable downtime to replace, therefore a financial incentive exists to preserve this high-cost item. Other issues created at the transfer include health risks of uncontained dust and product losses due to spillage. Additional consideration to support the belt is one way to improve the life of components and contain dust within the transfer chute. The humble impact cradle/bed has changed little over the years whilst conveyor systems have achieved ever greater flow rates. Further development of the impact cradle is an opportunity to reduce maintenance costs and increase uptime. The peak technology on the market for conventional impact belt support is the dynamic impact cradle, which ensures the belt support area under the chute allows for some dynamic travel, whilst also maintaining a consistent skirt board area. The impact energy at a transfer when installed with Kinder Australia’s dynamic impact belt support system was measured to further understand the forces involved and how they compare with static belt support systems. Adding further dynamic capacity to the load zone has been shown to increase belt life by at least 30 per cent. Other components also benefit from reducing impact energy in the transfer and the incorporation of polyurethane bushes at roller supports has been employed further increase roller and frame life. Kinder Australia has developed a unique and innovative range of belt support technologies that further promote dynamic travel whilst maintaining a consistent skirt board area without a significant increase in belt-friction tension. This technology combines slider rails with rollers that can absorb impact independently within the support system and/or utilising exotic slider materials to overcome high belt speeds and/or system capacities. Kinder Australia has a vast library of documented case studies and application data to ensure the future systems being offered will survive, provide better chute sealing and protect the conveyor belt.

Sep 18, 2023

By D N. B Skinner, R L. Brathwaite, M S. Rattenbury

The Institute of Geological and Nuclear Sciences is undertaking a mineral resource assessment study of the Coromandel region, due for completion in July 2000. A key part of the study is the assembly of a geographic information system (GIS), a computerised tool for layering, analysing and presenting spatial information. The GIS is being assembled with ArcInfo/ArcView software and to date includes layers for a digital terrain model, an aeromagnetic map (open file mining company data), a geological map (from the QMAP project), areas of hydrothermal alteration, locations of mineral deposits (GERM database), stream sediment geochemical analyses (REGCHEM database), and a lineament map derived from satellite remote sensing data.

Jan 1, 1999

No one process, product or effect of the minerals sector can be viewed in isolation when addressing sustainable development. Meaningful assessments of the minerals sector require that its processes and production are drawn together in a generic framework that gives a holistic view of its performance and progress. Lifecycle Assessment is increasingly accepted as an appropriate means of constructing such a framework. It is a step beyond using the simplistic concept of the triple bottom line of social, environmental and economic performance to drive and communicate sustainable development. However, fundamental questions need to be raised about the scope and purpose of lifecycle assessment, such as what effects and performances should be assessed, for whom should they be assessed, and what performance indicators should be used and how should they be selected. The principles of eco-efficiency, industrial ecology, The Natural Step (TNS) and other pertinent philosophies and initiatives driving mineral sector sustainable development are outlined to support a lifecycle stewardship vision for the minerals sector. Articulating this vision through a holistic lifecycle indicator system showing inputs and outputs, natural partnerships, effects on community, environment and economy facilitates recognition of problems, opportunities and partnerships that can be usefully pursued.

Jan 1, 2002

Planning for the Macraes Extension project highlighted the need for additional tailings storage availability. The possible solution of developing new tailings impoundments in Northern Gully, in tum, led to concerns being expressed by the regUlatory authority over the assimilative capacity of Deepdell Creek. Philosophical differences over the appropriateness of applying a seepage model used to set standards in consents for the original project resulted in the company re-evaluating the whole monitoring system associated with tailings disposal and seepage control. Re-evaluation indicated problems arising from the existing in-stream water quality monitoring in respect of protection of the aquatic ecological system and verifiability of results. A new monitoring system was designed relocating the compliance monitoring point out of the stream and into the gully containing the tailings impoundments giving greater certainty of monitoring results to all parties and providing improved protection for the aquatic ecology of Deepdell Creek.

Jan 1, 1993

Research on the Design and Processing Characteristics of 320 m3 Air-Forced Mechanical Flotation Cell

Sep 13, 2010

Smarter Gravity Separation Using the Kelsey Centrifugal Jig With relatively coarse grained and easy-to-process ore sources rapidly dwindling, smarter techniques are becoming more necessary for the continued success of mineral processing operations, while increasing environmental pressures also require more environmentally friendly solutions. Gravity concentration has long been employed to pre-concentrate minerals using water, reducing or eliminating the need for less environmentally friendly processing techniques such as flotation. Conventional gravity recovery devices however, operate in a 1 g environment with limited efficiency in the separation of fine particles of heavy and gangue minerals. More recently developed centrifugal concentrators operate in a multi-g environment and enable finer heavy minerals to be recovered, but also exhibit limited separation efficiency due to the separations being based on solid particle mass differentials. Further enhancement of gravity separation has been achieved using the Kelsey Centrifugal Jig (KCJ), which also operates in a multi-g environment, but separates minerals on the basis of specific gravity differentials, using 'ragging' media and a pulsation mechanism, which maximises the effect of differential particle accelerations. This enables the efficient separation/recovery of minerals down to a particle size of ~6 ¦m and/or separation of minerals with a low specific gravity differential. This paper presents details on the principals of operation of the KCJ, recent improvements in the technology and recent developments in modular KCJ plants, as well as some KCJ application areas, which offer smarter, environmentally friendly processing opportunities for the mineral processing industry.

Sep 13, 2010

By W J. Rankin

Metals are well suited to sustainable development goals. They are not biodegradable and have virtually an unlimited lifespan and the potential for unlimited recyclability. Thus metals can be considered as renewable materials. However mineral resources, the source of primary metals, are ænon-renewableÆ as their supply is finite, but this does not necessarily mean scarcity. In this paper the results from a series of Life Cycle Assessments of primary metal production processes for copper, nickel, lead, zinc, aluminium and steel have been used to examine how metals may contribute to societyÆs transition to sustainable development. Particular issues considered include:current metal reserves and how these may change in the future; some of the environmental impacts (Total Energy, Global Warming Potential and Acidification Potential) associated with primary metal production and how they will be exacerbated by declining ore grades; new processing technologies with lower energy consumptions and improved metal extraction efficiencies that will reduce reserve depletion and environmental impacts; increasing the utilisation of æmetals in useÆ by recycling, with particular reference to aluminium; and the potential impact of a carbon tax on metal prices and how this may influence the ways in which metals are used in the future.

Jan 1, 2002

To George Orwell the year of 1984 was the inspiration for a book. To most New Zealanders it was the year that the fourth Labour Government was elected to power. It was also the year that the review of mining legislation commenced. While Orwell's book and the election of Labour are clearly events of some historic note, one could be excused for classifying the review of minerals legislation somewhat differently in terms of its present achievements! Since the review began it has led a tortuous path through a rapidly evolving policy environment to a point three years hence where no major policies have been determined.

Jan 1, 1987

By J Coward, S Bulatovic

There are currently two operators producing oil from the surface-mineable portions of AlbertaÆs oil sands (Syncrude Canada Ltd and Suncor Inc) and two other companies are proposing to enter the industry (Albian Sands Energy Inc in 2002 and True North Energy LP in 2004). Tailings from the two current oil sands plants contain approximately 220 000 tonnes per year of TiO2 and approximately 80 000 tonnes per year of zircon. This represents approximately six per cent of the worldÆs TiO2 consumption and approximately nine per cent of the worldÆs zircon production. With the commissioning of plants by Albian and True North, and the announced expansion of plants by Syncrude and Suncor, it is expected that these tonnages could quadruple in the next ten years. All of these operators have at least 50 years of reserves even at these expanded production rates. The occurrence of heavy minerals in AlbertaÆs oil sands has long been known and is well documented in the literature. There have been a number of attempts to produce market-grade products from this resource and the results of this work have been quite mixed. Typically, researchers have used the normal mineral dressing techniques of the industry and have found the mineral assemblage does not respond to these techniques all that well. This has led to the widely-held suspicion that there must be some difficult metallurgical problems associated with this resource. There are three main problem areas that have created difficulties for previous researchers:the bitumen coating on the sand grains; secondary mineralisation such as pyrite, siderite and calcite; and a high proportion of aluminosilicates (approximately 25 per cent) that have the same gravity, electrostatic and magnetic properties as other minerals in the heavy mineral suite. Recent work by Lakefield Research shows that these problems can be largely overcome with some novel approaches. The bitumen can be removed by washing with a solvent in the presence of a demulsifier; the pyrite can be removed by flotation; and the titanium and zircon minerals can be separated by selective flotation followed by conventional electrostatic and magnetic separation.

Jan 1, 2001