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By T Day, I G. Robertson, G J. Lyman

"Various approaches are used in the industry for establishing procedures (sample mass estimation and method of subsampling) for sampling and analysis of gold ores. The key factors that determine the accuracy of the results that can be expected for a given set of procedures are widely misunderstood.Recent developments in sampling theory show that the estimation of the accuracy that can be expected for a given gold ore as a function of sample mass is actually a simple matter. For a given sample mass, the accuracy that will be achieved depends only on the grade of the ore and the range of masses of the grains of the gold in the ore. This, of course, demands that a reasonable estimate of the distribution or spread of gold grain masses in the ore be known. But this is something that should be known if the gold is to be efficiently recovered in the processing plant.This paper provides a simple explanation of the real facts about sampling of gold, either in the field or in the plant, and provides results for a number of cases of combinations of fine and coarse gold in an ore. The prerequisites for accurate gold sampling are:correct sampling with no loss of sample or contaminationsample preparation procedures that recognise the impact of the gold grain mass spreadpractical analysis of the sample masses required to provide acceptable accuracy.Issues of corporate governance are also discussed.Citation:Lyman, G J, Robertson, I G and Day, T, 2016. The Simple Facts about Sampling Gold Ores, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 159–172 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By L P. Trout, D G. Reid

PanAust Limited (PanAust) has successfully constructed and commissioned two mining operations in Lao PDR over the past decade and undertaken major studies for three new mine developments. The management of potentially acid generating mine waste and tailings in close proximity of local communities sensitive to water discharge quality have been recurring themes that have confronted PanAust’s project study, development and operational teams. Further compounding challenges, such as the effects of intense annual tropical monsoonal conditions, staging of embankment raises and regular lifting of spillway structures, integrating mine waste and tailings management into production plans and ensuring the long term stability of structures, have been addressed by implementing leading practice management solutions.A recognition of the criticality of managing the substantial business risks associated with these crucial activities led to the early establishment of a governance structure to ensure that the highest standards are embraced for planning and execution. Importantly, these are guided and monitored by a panel of highly experienced and qualified international specialists reporting directly to PanAust’s Managing Director – the Tailings Independent Review Panel. The stewardship process has been effective in identifying potential shortcomings in management systems and has led to enhanced executive commitment to risk informed designs, assurance and overall process rigour.CITATION:Trout, L P and Reid, D G, 2018. PanAust Limited’s approach to mine waste and tailings stewardship, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 135–155 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By M P. Sandy, R M. Stephenson

Portals to access underground mines are important infrastructure and their design requires careful consideration. Portals are generally expected to last for the life of the mine. Typically, the exposure of personnel and equipment is high, with many hundreds of movements through the portal per day. Consequently, the risk associated with geotechnical instability must be extremely low. Portals are often established from a boxcut. In areas where the weathering profile is well developed, the design and execution of the boxcut can involve significant effort, with the objective of minimizing the volume of the boxcut, whilst ensuring that conditions at the design depth are suitable for establishing a stable portal. Properly designed site investigations are a critical part of this process. Currently available portal design guidelines have not been updated for decades, however the equipment and ground support systems have changed significantly in recent years. Many mine portals have since been constructed in a relatively short time frame with success, often in challenging ground conditions using some of the more modern approaches to ground support. This is beneficial because delays in establishing a portal will generally delay other critical path activities, and lead to cost overruns.

Mar 15, 2021

By A D. Campbell

The sublevel caving (SLC) mining method is becoming more widely adopted as an underground mining method as mines become deeper and target lower grade mineralisation. SLC has been successfully adopted in increasingly complex and wide-ranging conditions in the past 10–20 years, demonstrating the flexibility of the method. Various challenges encountered at SLC mines around the world have led to significant differences in operating practices, mine performance and mine productivity. Unfortunately, aspects related to productivity, operational performance and best practice are not widely published and remain with individual companies. Limited information is publicly available to compare operational performance of SLC mines in the various conditions where the mining method is now being applied. To overcome this shortcoming, a global review of SLC operations was undertaken over a three-year period as part of the Cave Mining 2040 research consortium. The purpose of the review was to document technical and operational practices, hazard management strategies and key benchmarking metrics at SLC mines around the world. A total of 21 mines spread over four continents and 17 different mining companies were included in the project. The main outcome of the project was a manual of operational and technical practices, benchmarking of key metrics and documentation of the current state-of-the-art for each aspect of SLC mining. This paper describes the main findings from the benchmark in terms of mine productivity, including mine development, production and mining costs. The implications of mine scale, depth and ground conditions on operational performance at each of the benchmarked mines is described and charts are provided comparing key productivity metrics.

Mar 29, 2023

The Health Tracking project is one of five projects being undertaken as part of the Minerals Industry Cooperation Initiative (MICI) û a national initiative sponsored by the Minerals Council of Australia. The aim of the Health Tracking project is to assess the practicality of ways to demonstrate the monitoring of hazardous exposures and the occurrence of related occupational illness and disease and development of management systems and strategies at a national level. This second stage of the project will be completed in 2005 and will cover four areas: pilot development of a comprehensive job exposure matrix (JEM) for the minerals industry; development of both proactive and reactive occupational illness and disease metrics; recommendations regarding appropriate health tracking models; and provision of best practices guidelines for management of occupational health. The synergies between these areas will establish the path towards an effective national occupational health surveillance system and the development of effective prevention strategies and policies.

Jan 1, 2005

By A Hamanaka

EGAT Mae Moh Lignite Mine in Thailand produces about 16 Mt of lignite annually from open-cut mining. The coal is used to generate 2400 MW of electricity. In the near future, however, the coal must be extracted from underground at 400 - 500 m deep from the surface. The problem is the thickness of the coal seams. There are two coal seams that are about 25 m thick with 20 - 25 m of interburden between them.In order to investigate thick seam mining systems and propose a new mining system in ultra-thick coal seams in Thailand, a joint research group was established by Japanese and Thai researchers and mining engineers in early 2009. This paper describes conventional underground mining systems and underground coal gasification for thick coal seams and discusses the applicable coal mining systems to this mine. Then, this paper proposes an innovative underground coal mining system for thick coal seam, ‘eco-friendly underground coal mining system which consists of the utilisation of flyash and CO2 storage’.

Nov 22, 2011

As Pliny commented two millennia ago, The only certainty is that nothing is certain. Despite the many breakthroughs, advances and promises, the way we each live and work remains awash with technological, economic and political uncertainty. The resources sector is no exception in this regard. Mining itself is much more than a complicated process or recipe; it is a complex adaptive system. The way we adopt and adapt new technologies, the way we evolve data into corporate wisdom, the way we make decisions and even the way we view our concept of rationality should each be the subject of intense review. Translating these sentiments into sustainable company growth is indeed the challenge. This is unlikely to be achieved within convention, but through innovation. The game is changing!

May 1, 2010

By D Capstick, M B. Ebell

This paper describes the test work, process design, commissioning and operation of a processing system at the Ergo gold operation that improves the extraction efficiency from gold tailings material. The improvement in recovery is derived from the separation of the gold contained within the sulfides of the tailings material and a dedicated process stream to recover that gold.The sulfides are separated by means of a flotation circuit and that resulting concentrate is subjected to a regrind of below 20 ¦m to enable a greater liberation of the gold. The ultra-fine material is then subjected to a dedicated leach circuit to recover the now exposed gold particles.The case study is an example of the challenges of introducing new technology and methodologies to a well-established operation and thereby attaining improved efficiencies and tangible business benefits.CITATION:Ebell, M B and Capstick, D, 2013. Improving extraction efficiency from Witwatersrand gold tailings using flotation and ultra-fine grinding of concentrates, in Proceedings World Gold 2013 , pp 301-306 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By J Deraisme, P Epinoux, O Bertoli

"Société le Nickel exploits the Dôme lateritic nickel orebody at its Tiébaghi operations in New Caledonia. The site geology has an obvious bearing on recovery and metallurgical performance, with controls that are extremely complex at all scales, including lithology, oxydo-reduction conditions, mineralogy and multivariate geochemistry. In this context, establishing an adapted recoverable resource estimation method that is efficient and transparent proves an interesting challenge. The method must address the key notions of: support effect – the exploration data set can only warrant the estimation of large panels of 20 × 20 × 3 m3 that are much larger than the selective mining units (SMUs) of 5 × 5 × 3 m3 information effect – the selection at the production stage uses estimates based on information that is much denser than that available for mine planning.The problem is rendered more complex in this type of deposit by the fact that the additive variables used for the estimation (metal accumulation and ore tonnage) are not the ones used to establish the selection at the mining stage (ie the nickel grade of SMUs, which is the ratio of accumulation on tonnage). Eventually, the selection criteria not only involve Ni grades, but also other elements such as Al2O3, Fe2O3, MgO and SiO2.The solution presented in this paper is to construct an SMU multivariate simulation in the saprolitic horizon and construct an efficient post-processing aimed at producing multivariate recoverable resource estimates. The efficiency constraints imposed by the number of blocks to be simulated (1.5 million) lead to resorting to direct block simulations. The underlying multivariate discrete Gaussian model, which had its validity tested beforehand, is put to good use to mimic the selection process that happens at the mining stage by offering the ability to simulate a composite value located at random within each block.The paper also presents the application of a scenario reduction algorithm to pick a representative subset of a few simulations to help appraise the risk attached to the downstream (reserve optimisation and mine sequencing) phases of the project. The original version of the paper (see Deraisme, Bertoli and Epinoux, 2014) used an early version of the scenario reduction plug-in (named S2RM) built in Isatis® software, where measuring the distance between the initial set of scenarios and the reduced set was based on Ni only. The implementation presented here is for the second generation of S2RM, where measuring the distance between the initial and the reduced set of realisations is based on all study variables. The benefits of the measure adapted to the true multivariate nature of the problem are highlighted in this updated version of the paper.CITATION:Bertoli, O, Deraisme, J and Epinoux, P, 2014. Multivariate block simulations of a lateritic-type nickel deposit and post-processing of a representative subset, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014, pp 99–108 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 24, 2014

By W Curlewis, D Hake, Z Cuthbert

The South Island Line (East) will be a medium-capacity railway covering approximately 7 km from Admiralty Station to South Horizons Station on the south side of Aberdeen Harbour in Hong Kong, with intermediate stations at Ocean Park, Wong Chuk Hang and Lei Tung.South Island Line (East) Contract 904 project is located on the island of Ap Lei Chau at the southern side of Hong Kong island and requires extensive construction works to be completed in close proximity to the existing residential estates of South Horizons and Lei Tung. The project also has areas of significant cultural heritage, including 18th and 19th century temples and historical gravesites. Owing to the site access constraints and location for the project, detailed planning and methodology innovations have been required to ensure the most effective and responsible means of delivering the project works. To excavate the tunnels using drill-and-blast techniques in these restricted locations, the maximum instantaneous charge weight that could be fired while blasting was severely limited. To overcome these restrictions, the project team developed and pioneered the use of ‘deck loading’ in Hong Kong to minimise the impact of blasting operations and has successfully implemented double- and triple-deck blasting operations during the completion of tunnel excavation works.Upon completion of the drill-and-blast excavation, the tunnel lining works were completed using both in situ concrete lining with travelling forms and permanent shotcrete works.CITATION:Curlewis, W, Cuthbert, Z and Hake, D, 2014. SIL904 Hong Kong – Drill and Blast Tunnels, station blasting innovations (double- and triple-deck blasting) and lining solutions, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 21–28 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By S J. Schafrik, C Keles, C Schlosser, E S. Gilliland, A K. Louk, N S. Ripepi, S Keim, J Amante, E Diminick

Three legacy coalbed methane production wells have been converted to injection wells for a one-year carbon dioxide (CO2) injection test to evaluate the potential for CO2 storage in the coal reservoir and the potential for enhanced gas production at offset wells. The injection reservoir is composed of 15–20 individual coal seams with an average thickness of 30 cm (1.0 ft), spanning a depth range of approximately 240 (800 ft) to 670 m (2200 ft).The monitoring program for this test includes gas and water sampling of the three injection wells, three dedicated monitoring wells and approximately 20 offset production wells. Key technologies used for monitoring the study area include time-lapse GPS and interferometric synthetic aperture radar (InSAR) acquisitions for surface deformation measurement, a 28-station buried passive microseismic monitoring array, real-time downhole pressure and temperature sensing and perfluorocarbon tracer fluids, which will be injected with the CO2 stream. The schedule for the monitoring program includes pre- (baseline), during- and post-injection data collection. This schedule will allow data to be analysed for time-lapse changes and trends, which are important for understanding the migration of gas and fluid phases in the reservoir – including CO2, methane, other hydrocarbons and water – and for observing the changing distributions of reservoir pressures and stresses.The results of the monitoring efforts for this study have implications for monitoring mining operations. The combined use of GPS and InSAR geospatial data to evaluate elevation changes across and beyond the study area may prove to be an accurate option for measuring surface deformation, including mining-induced subsidence, in unstable terrain. Long-term microseismic monitoring using high-sensitivity instruments has several applications in mining operations, including rock stability monitoring, production monitoring and miner location detection during emergencies. Tracer studies and short-term microseismic monitoring used to assess methane extraction can also be used to develop and optimise degasification systems for underground coalmines.CITATION:Gilliland, E S, Ripepi, N S, Schafrik, S J, Schlosser, C, Amante, J, Louk, A K, Diminick, E, Keim, S, Keles, C and Karmis, M, 2015. Monitoring design and data management for a multiwell CO2 storage/enhanced coalbed methane test in a stacked coal reservoir, Buchanan County, Virginia, USA, in Proceedings Third International Future Mining Conference, pp 47–56 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

By M S. Reston

The Tonkolili banded iron formations (BIF), Sierra Leone, host extensive iron ore deposits which are of economic signifi cance to the seaborne iron ore trade. The deposits are dominated by a strategic JORC compliant mineral resource of 11.6 Bt grading 30.1 per cent Fe comprised of primary magnetite mineralisation in the form of a fresh metamorphosed BIF featuring a uniform mineral assemblage of quartz-magnetite ± ferro-silicate minerals. Pilot plant metallurgical test work has demonstrated that the production of a magnetite concentrate is achievable using the established beneficiation techniques of magnetic separation and flotation. The concentrates arehigh-grade, and suitable for blast furnace or direct reduced iron pellet feed. The major challenge facing the development of such magnetite deposits at industry competitive production rates is the significant capital investment required for process plant and associated infrastructure.Two well-developed weathering zones exist within the deposits, and are associated with the progressive development of a tropical weathering profile overprinting the primary BIF. These zones feature a near surface hard indurated duricrust up to 60 m thick, and a soft progressively developed saprolite between duricrust and fresh BIF. These zones have been found to be amenable to producing iron ore products including DSO lump and sinter fines from the duricrust, and concentrate from the saprolite. Mineral resources sufficient to support commercial production of such iron ore products were defined by an intensive exploration program in 2010.African Minerals Limited has developed a three phase production strategy to progressively self fund the development of the Tonkolili strategic magnetite project by:• commencing a Phase I 12 Mt/a DSO operation in Quarter 4 2011,• increasing production in Phase II to 35 Mt/a with the commissioning of a saprolite beneficitation plant and associated infrastructure upgrades, and• developing a 45 Mt/a Phase III operation producing high-grade magnetite concentrate.The comparatively low capital and operating costs of a duricrust DSO lump and sinter fines operation coupled with its proximity to ground surface make it highly attractive for the generation of early cash flow for the Tonkolili project. Revenue from this early production may be used to selffund the subsequent development of phases requiring progressively more significant beneficiation plant and infrastructure.

Jul 11, 2011

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

By D Kilkenny

Underground contractors in the mining industry must be prepared to take a position at the forefront of innovation of equipment and work methods in order to maintain a competitive advantage over in-house operations and remain relevant. Innovative concepts such as split-feed development jumbos, high capacity trucks and loader guidance systems were implemented by contractors to stay ahead of ‘the pack’. All of these are now common across the industry.The demands of regular participation in competitive tendering coupled with aggressive fleet depreciation, means contractors tend to have more communication and opportunities to work with equipment suppliers than mine owners. Therefore, they are more likely to influence equipment design and product directions. They also have a unique opportunity to assist in trialling new concepts and technologies across a wide variety of operating conditions rather than being restricted to one mine.In addition, as a ‘guest’ on a mine site, mining contractors do not have the luxury of creating the environment for their preferred systems, rather they must have the capacity to adapt their technology to suit the offered environment at a particular mine. This leads to a pursuit of adaptive technologies that can be implemented selectively and seamlessly without excessive disturbance rather than ‘all-of-mine’ systems. These incremental innovations then become available for use across the mining industry where they can add value as ‘bolt-on systems’ to existing operations.Mining contractors, therefore, act as the bellwether for industry practices and equipment. However, in order to maintain their position they must engage industry stakeholders to deliver practical, innovative and cost-effective technologies that add value and result in an improved bottom line for all. This paper uses case study material to illustrate how the Byrnecut Group has approached innovation and how the theory of Disruptive Technology applies to underground mining innovation.CITATION:Kilkenny, D, 2017. Innovation in mining – a contractor’s role, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 59–68 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017

By M Haest

This study demonstrates the application of HyLogging™ technologies for mineralogical characterisation of different iron ore types throughout the Hamersley Province (Western Australia), including a channel iron deposit (Murchison Metals Ltd) and bedded iron deposits in the Brockman and Marra Mamba Iron Formations (BHP Billiton Ltd).Drill core from these deposits was analysed using CSIRO’s hyperspectral drill core logging systems (HyLogging systems), which are commercially available at the AMDEL and AMMTEC laboratories in Perth (Western Australia), through a leasing agreement. These HyLogging systems provide high resolution photographs at 0.1 mm pixel resolution as well as visible and infrared spectroscopic refl ectance data at 1 cm spatial resolution. The minerals identified include haematite, goethite and its subtypes (ie vitreous and ochreous goethite), AlOH-clays (kaolinite, Al-smectite and white mica), carbonates, gibbsite, chlorite, amphibole and hydrated silica as well as water content. The abundance and composition of these minerals was established from the spectral data and was validated against XRF analyses.The full potential of HyLogging systems in the iron ore industry is only starting to be unveiled, but some major benefits have already been demonstrated:• HyLogging systems can delineate different ore zones by mapping the vitreous and ochreous goethites. This has a potentially large impact in mine planning and operations, as hard, vitreous goethite and soft, powdery, ochreous goethite have different processing characteristics that can affect plant throughput if not carefully managed.• HyLogging mineralogy can also be used to support stratigraphic interpretations of the host, for example in subdividing the Dales Gorge 1 - 4 submembers of the Brockman Iron Formation.• HyLogging can have a potentially signifi cant impact on waste rock characterisation, as many of the waste materials can be identifi ed and quantifi ed with hyperspectral data (eg clay-type,• hydration state).• HyLogging can provide accurate three-dimensional (3D) mineralogy to iron ore companies that will empower them to improve future exploration and resource planning.• Application of high resolution photography to further improve ore deposit domaining is also to be considered.

Jul 11, 2011

By A Dal-Corobbo

Traditional acid and metalliferous drainage (AMD) wastewater treatment focuses on the iron co-precipitation/adsorption process as this is a very effective method of reducing heavy metals, including copper, lead, zinc, arsenic, etc, to parts per billion (ppb) levels in AMD wastewater streams. One of the drawbacks to this method however is the large volume of sludge produced and subsequent disposal costs for the mine site concerned.A proprietary metals treatment system called high density sludge (denoted HDS) which significantly reduces the quantity of waste generated is described in this paper. This process generates a dewatered sludge that contains in the order of 50 to 55 per cent solids. This sludge is denser than conventionally dewatered sludge, which typically contains only 20 to 30 per cent solids. This advanced process has a wide range of applications and can be easily retrofitted into existing AMD treatment systems. It has been successfully installed at several mine sites to treat AMD wastewaters. This paper discusses the high density sludge process, its benefits and provides data and operating results from pilot test installations.CITATION:Dal-Corobbo, A, 2013. High-density sludge process for treating metal bearing acid and metalliferous drainage wastewaters, in Proceedings Water in Mining 2013 , pp 217-220 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

Morning Star Gold aims to enter the ranks of Australia's gold producers, revitalising the Eastern Victorian Goldfi elds in the second half of 2010 - the fi rst gold production in around 50 years from the Morning Star Gold mine, which was once Australia's largest under WMC. This presentation will outline the redevelopment of the Morning Star Gold Mine from exploration to production. Morning Star Gold NL's (MCO) key project area is centred at the historic mining town of Woods Point and nearby Matlock (to the southeast) and Gaffney's Creek (to the northwest), all of which are located in the lower part of the Victorian Alps roughly 60 kms south of Mansfield. Morning Star has literally numerous historic mines and gold bearing 'dykes' on its tenements, many with a rich production history of high-grade gold from quartz reefs and alluvial sources. The area encompassing the Woods Point goldfi eld and the multiple high-grade gold bearing dyke structures located north towards Jamieson and south towards Walhalla formed one of the most significant mining fields in Australian history. Historical gold production was at least 155 t or around six million ounces of over a century of mining with an average production grade exceeding 27 g per tonne. The bulk of this recorded production came from just a handful of mines and of those only three were mined to any great depth. One of the key historical production hubs in this area was the famous 'Morning Star' mine, which is situated adjacent to Woods Point township. The Morning Star mine produced almost one million ounces at 27 grams per tonne, operating fairly continuously between 1861 and 1959 with a break after Jan 1939 due to the devastating 'Black Friday' bush fi res across eastern Victoria. During the early 1940s, the Morning Star was Australia's biggest gold mine. The Morning Star mine along with Walhalla ensured that this goldfield was third behind Bendigo and Ballarat as Victoria's biggest hardrock gold production centre. Morning Star Gold has rebuilt its 100 per cent owned 'Morning Star' mine with a view to producing gold in the second half of 2010. Morning Star is exploring its regional dykes in order to estimate an overall gold endowment and rank local production sources to feed its proposed mill at the Morning Star mine site. Key initial targets (all within 11 kms of the Morning Star mine) are the Waverly, All Nations, Rose of Denmark, Hunts, Wallaby and Loch Fyne dykes, all of which historically produced high grade gold, much of it gained from only shallow workings above the water table in the weathered zone of rocks. Historically the Morning Star mine was developed over 24 levels to a depth of 940 m via one large vertical shaft and a smaller, deeper inclined shaft at the 1900 feet level underground. At present MCO has dewatered and completely refurbished all infrastructure to the ten level (~310 m below surface). MCO knows there are a number of substantially under-explored and undeveloped or partially developed but not stoped areas within the Morning Star mine. As a result, MCO has been carrying out extensive channel sampling and an underground diamond drilling program targeting areas of the mine that were largely unexplored and undeveloped by the last operators of the mine - Western Mining Corp Ltd (Gold Mines of Australia). Four thousand, fi ve hundred pages of archival WMC records have helped the cause significantly. The shaft refurbishment and reconstruction stage is complete. This has been a program that originally commenced back in 1993 and has cost around $22 M. This refurbishment paved the way for the extensive underground resource focused diamond drilling program, which MCO completed in 2008 with two company-owned and operated drill rigs from drill cuddies on level 9 (900 feet underground) of the mine. This drilling, which encountered some stunning grades intersections and multiple visible gold hits, has outlined further production opportunities including 0.4 m @ 1392 g/t Au (MS 410). Metallurgical testing conducted by Gekko Systems of samples obtained from the exploration program found gravity concentration and a leach circuit gave recoveries of ~95 per cent to 99 per cent, or ~92 per cent from gravity alone at a coarse crush (300 ¦m). Currently, the plan is to use gravity to fi rstly produce dore bars on-site from the free milling gold and secondly a saleable concentrate for CIL processing off-site. A purpose built 10 t/h (~80 000 t/a) gravity treatment plant was subsequently ordered from Gekko and is expected to be installed onsite and commissioned in the Q3 2010. The plant features fi ne crushing with a vertical shaft impactor, followed by gold concentration by inline pressure jig, inline spinner and Wilfley table. This is an ABSTRACT ONLY. No paper was prepared for this presentation.

Aug 1, 2010

By K Henley

One of the greatest practical difficulties of measuring airblast occurs when a significant wind is blowing onto the microphone. Small windscreens are usually used to mitigate the wind noise on the microphone, but in some wind conditions, sound pressure levels (SPL) of over 120 decibel (linear) are frequently recorded. There are no specific procedures to mitigate the effect of wind noise when measuring airblast in any of the standards or guidelines pertaining to the measurement of airblast from blasting operations, other than the requirement to use an effective windscreen. A search for relevant literature was undertaken and measurements were taken over a period of six months at a test site using alternative microphone measurement methods. Previous researchers’ experiments with windscreens in silenced wind tunnels showed that wind noise can be reduced through the use of large diameter windscreens, and that at low frequencies, the windscreen size and the material type makes no difference to measured SPL values. Other researchers found that wind turbulence caused significant SPL measurement problems. A comparison with field data failed to explain the extremely high SPL recorded by the field microphones at wind velocities much lower than those used in wind tunnel testing. It has been concluded that turbulent airflow over and behind the microphone is a significant contributor to extraneous noise in airblast measurements in windy conditions. This turbulence can be generated by objects upwind of the microphone or by the microphone itself if the windscreen is ineffective. Reducing the wind speed over the microphone by placing it on the ground is the approach required by the international standard for the measurement of noise from wind turbine generators (IEC 61400–11). This paper presents data that illustrates the extent of the problem, reports on the trial of three different microphone mounting locations for measuring airblast from blasting and concludes that in windy conditions, microphones placed on the ground substantially avoid wind problems and do not reduce the measured SPL of the airblast.CITATION:Henley, K, 2015. Reducing the effect of wind on airblast measurement during blasting, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 485–492 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By M Allen

By its nature, the mining industry is energy and emissions intensive. In the future, the world will still require the outputs of mining but the industry will need to adapt to the low emissions economy. Understanding the risks of climate change to a particular site or at a company level is key to managing this transition.CITATION:Allen, M, 2018. Assessment of climate risk in the Australian mining industry, in Proceedings Life-of-Mine 2018, pp 13–16 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By J Allen, B Oats, S Palaniandy, M Lollback

The Julius Kruttschnitt Mineral Research Centre has conducted an intensive VertiMill® (VTM) survey program at the Cannington mine concentrator as part of the ‘collaborative research in stirred milling technology’ program funded by Metso Minerals. Since 2003, Cannington has progressively added grinding capacity into the circuit through VTMs operating in secondary and regrinding duties. Cannington was one of the first mines to adopt this technology in secondary duty by installing two VTM-1500-WBs as part of a capacity expansion to produce sub-100 µm rougher feed. Subsequently, an additional VTM-800-WB was installed in the lead regrind circuit to prepare sub-20 µm cleaner stage feed.Several surveys were carried out to evaluate the VTM performance over a range of changed conditions. Among the key changes in operating variables were circuit power draw, feed rate and water addition to the bottom of the mill. The average specific energy for secondary duty was 3.7?kWh/t. The lead and zinc regrind mills consume 8.1 and 15.3 kWh/t respectively. Generally, the VTM installations have successfully prepared feed for rougher and cleaner circuits by reducing the top size into the floatable regime with steeper particle size distribution, which has led to enhanced recovery. The survey results show the success of VTM installations in secondary (receiving feed from autogenous circuit) and regrind duties.CITATION:Palaniandy, S, Powell, M S, Hilden, M, Allen, J, Kermanshahi, K, Oats, B and Lollback, M, 2014. VertiMill® performance updates in secondary and regrind duties at Cannington mine, BHP Billiton, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 263–272 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014