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By P Mulvey, M Stuckey

"Inter-aquifer leakage due to fractures caused by coal seam gas extractions or longwall mining is an important issue for both the gas and coal industries. Currently, predicting stress induced macro-porosity associated with hydraulic fracturing, depressurisation via dewatering or collapse of overlying seams to infill a void left by longwall mining, is problematic. If fractures can be located the fracture can be sealed. Locating fractures is difficult. The non-geophysical approaches to locate fractures has been to consider the mixing of different waters, particularly that of more recent shallower groundwater with older deeper groundwater, via differences in radio-isotopes integrated with geochemical models to predict likely mixing of waters. This approach is applicable under appropriately complex settings; however, it is an expensive technique and is based on the assumption that the daughter isotopes are equally non-reactive which may not always be the case.Potentially a cheaper and faster technique is to consider integrating geochemistry (mineral weathering) and hydrogeology. The chemistry of groundwater, controlled by the weathering of primary rock?minerals and?formation of secondary minerals, can not only be differentiated between geological strata but also within strata as different stages in weathering results in differing impacts on water quality (ie different reactants).Field analysis of pH, electrolytic conductivity (EC), oxidation reduction potential (ORP) and dissolved carbon dioxide together with laboratory analysis of dissolved constituents characterise the chemistry of the water. Collection of rock samples at the time of drilling for bore installation can provide the (only) opportunity to assess the media in which the groundwater resides and migrates through. An assessment of aquifer matrix chemical makeup, via bulk sample chemical analysis, X-ray diffraction (XRD) and petrographic analysis can achieve this.The chemistry of groundwater is dependent on the water velocity. Water at deposition and post-diagenesis dissolution of minerals by hydrolysis and oxidation will result in equilibria of the dissolved phase with the solid phase. Post-depositional fractures caused by either tectonic activity or weathering alter the rate of weathering and thereby the geochemistry. Slow water flow in microfractures results in water in equilibrium with the rock minerals. Faster flow in larger fractures results in water being in disequilibria with rock minerals.Fractures can alter groundwater chemistry by two pathways: changing groundwater velocity, which changes the rate of hydrolysis or oxidation mixing water from different geological strata.Both pathways cause subtle changes in the water chemistry.It is however, the dissolved phase chemical data, which can be observed over time at individual locations and/or at a point in time along a flow path, which allows the hydrogeologist to ælook up-gradientÆ and locate the zone of leakage. Hence, influences on rock/groundwater chemistry, from anthropogenic sources to natural mixing of waters, can be assessed via appropriate interpretation of geochemistry, hydrogeochemistry and flow data.This paper will use the example of the geochemical and hydrogeological characterisation of aquifers within the Hawkesbury and Bulgo Sandstone of the Southern Coalfields to the south of Sydney in New South Wales to demonstrate this approach.CITATION:Stuckey, M and Mulvey, P, 2013. Looking for fractures - integrating geochemistry with hydrogeology to find inter-aquifer leakage above dewatered or collapsed coal seams, in Proceedings Water in Mining 2013, pp 99-108 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 26, 2013

By W Baguley

Attritioning has been a method of improving mineral extraction for over 60 years, however it is only recently that an understanding of the mechanism employed and the improvement in efficiency that have been achieved.The paper will discuss these improvements and how to overcome the problems that have been raised. At present there is a dearth of information on the correct design and operation of these machines.The paper will address these issues as well as fluid on the Zeta potential, micro shear, retention residence time and pilot plant operation.A study on the hydrodynamics of attritioner operation has been identified and will be discussed.Surface chemistry, clean lines of attrition material and the treatment of fines significant advances in the understanding of attritioning highlighted.CITATION:Baguley, W, 2013. Attrition scrubbers, in Proceedings MetPlant 2013 , pp 229-246 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

By F Weir, B Estrada

The impact of seismic loading on open pit slope stability in Australia is often only considered where the slopes are located adjacent to tailings facilities or other major infrastructure. The debate regarding application of seismic loading in open pit design in Australia is usually founded on limited reporting on significant damage of open pit operations during earthquakes, the common perception that earthquakes do not occur in Australia or that they are unlikely to occur during the mine life of the mine. It is frequently overlooked that pit slopes that have withstood strong earthquakes in highly active seismic regions are often designed under strict seismic guidelines. This paper discusses the factors that impact earthquake performance of open mine slopes. These factors include topography, slope geometry, rock material and mass properties, water management and intrinsic pit design. Further, the paper presents insights into the characteristics of earthquake activity in Australia such as magnitude distribution, earthquake depths, areas prone of earthquake activity and general seismic hazard that are relevant to pit design. Guidelines are provided on the conditions and circumstances under which earthquake design in open pit mining should be considered. In addition, this paper provides recommendation on the applicable methods for assessment of the impacts of earthquake loading on pit slope stability.

Jun 22, 2022

By D Kilkenny

This paper discusses the use of a mechanised shaft sinking machine Herrenknecht Vertical Shaft Sinking Machine (VSM) – to conduct the 93 m presink for the Wira Hoisting Shaft at the Prominent Hill Mine in South Australia. This technology has been widely used in the global construction industry, however, this was the first time it had been used in Australia and the second time in a mining application. The non-entry shaft sinking system eliminates risks associated with a traditional manual method and allows all shaft construction operation to take place from surface. The geology in the upper 100 m at the Prominent Hill mine is conducive to mechanical excavation, with expected rock strengths below 130 MPa. This enabled an alternative shaft construction methodology to be considered. The Herrenknecht VSM system was selected due to its extensive work history and demonstrated performance in similar ground conditions. In collaboration with the operations and design team, the shaft collar and surface configuration were modified to suit the requirements of the VSM, additional equipment, and loading jacks that support the pre-cast lining. Dedicated concrete moulds were designed in Germany and built in Italy. The concrete segments were cast in Adelaide and road freighted to site. This paper outlines each stage of the presink – refurbishment, transportation, logistics, establishment, operation and demobilisation. Selecting this shaft presink excavation methodology, delivered through positive collaboration and communication despite some challenges, shows the benefit to the mining industry of applying new technology and innovation to improve safety and productivity.

Mar 29, 2023

The state of sampling practice in South African minerals industry must be appreciated in the context of the changes that the country has recently lived through. These include the entrepreneurship and investment in local mineral developments, the 'unbundling of mineral assets', the rising foreign control of South Africa's mineral assets, developments in the regulatory environment, and the training that has come to the industry through international experts. In terms of their financial contribution the five most important commodities in the South African mining industry include gold, platinum, non-ferrous metals, ferrous metals, and coal. International Organization for Standardization (ISO) standards form the basis for international trade in two of these commodities and have had a steadying influence on sampling practice over the years. The contribution of the minerals industry to the economic well-being of South Africa and the strong financial links between good sampling practice and minerals marketing, has acted as a driver for improved sampling practice. The state of sampling practice at mining operations of the five main commodities was found to be quite widely divergent with 'pockets of sampling excellence' in each of the commodities. The stages of mineral development at mines for each of the commodities have been described in terms of the sampling sites, sampling mechanisms, and associated problems at different stages of mineral production from exploration, through face sampling, blasthole sampling, and in-mine grade control, ore processing and handling, metallurgical subsampling, process subsampling, and subsampling in the laboratory. In each case the principal errors were identified and their potential impact on value erosion was estimated. In the final analysis it is evident that the greatest problems arise in the early stage of mineral development, and that ferrous metals and coal are particularly susceptible to loss of value through poor sampling practice. Several examples of value lost through poor sampling at the marketing stage that arise from breaching contract specifications, either in terms of grade or sizing, are described. The conclusion is that larger companies with larger ore deposits and greater human, financial, and capital resources are probably more compliant with 'best sampling practice' than smaller companies. Finally the message that equipment suppliers are sending is that business is booming and the awakened awareness of the issues around sampling practice are translating into rands and cents spent on improved sampling equipment.

Mar 1, 2010

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

Enhance Fine Particle Flotation by Hydrodynamic Cavitation Difficulties in fine particle flotation are well documented. Microbubble flotation has been found to greatly improve the recovery of fine particles and in situ gas nucleation by hydrodynamic cavitation incorporated in the design of modern flotation machines has shown great performance in fine particle flotation and potentially in coarse particle flotation. In this presentation, we will provide an overview on gas nucleation by hydrodynamic cavitation and its role in fine particle flotation with focus on the progress made in our research laboratory. Hydrodynamic cavitation was achieved and the critical role of dissolved gases in the liquid was elucidated by visualisation in a high intensity agitation cell. The in situ gas nucleation on fine particles by hydrodynamic cavitation was identified by zeta potential distribution measurement in model systems. Gas nucleation by hydrodynamic cativation was found to effectively aggregate hydrophobised fine particles thereby leading to enhanced flotation kinetics. This is an abstract only. No full paper was prepared for this presentation.

Sep 13, 2010

By D J. Thobaven

Project financing challenges caused by declining commodity prices have heightened the need to improve project metrics such as minimising capital payback and maximising net present value (NPV). Khnaiguiyah Mining Company (KMC) recognised the need to improve early cash flows at their Khnaiguiyah zinc-copper project after initial studies showed the project could not provide the desired financial outcomes necessary to compete for investment dollars in the current market.A significant improvement to the project cash flow in early years was realised through simultaneous optimisation of cut-off grade, mining sequence and strategic stockpiling. This improvement was achieved by accelerating mining in the pits, stockpiling lower value material and feeding higher value material directly to the plant. The schedule required higher mining and stockpile capacities than the sequential mine plan although minimal change occurred in the definition of ore and waste as measured by tonnes and grade. The practicality of the strategic schedule was demonstrated by implementation in the production plan with excellent conformance.CITATION:Thobaven, D J, 2014. An application of simultaneous optimisation – improving the payback period of a zinc-copper open cut project, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 137–144 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

A great range of contacting equipment is used in solvent extraction. However, a tower filled with a regular packing offers many advantages in the direct extraction from slurries. A study was made of the flow of a dense slurry through a packed tower in which the continuous phase was kerosene. The grid type packing, which was preferentially wetted by the slurry, had slats inclined at an angle of 30¦, to the horizontal. On the sur- face of the slats there were uniformly spaced longitudinal indentat- ions. These were of a height slightly less than the film thickness and divided the slurry discharging from the bottom of the slats into a number of uniform streams. When slurry entered the tower it was distributed by means of a troughs and weirs type of distributor. Because of the relatively high slurry velocities that occur at the entry region, it was necess- ary to have the distributor and the first two grids above the solvent level. The interface at the bottom of the tower was located at the mid-point of the bottom grid, so that the slurry entered the interface as a continuous film across the full width of the slats. Using the above system, stable flow with low entrainment was achieved at slurry flow rates of 3.4 mis/cm/sec. This would be equivalent to a flow rate of 177 gallons per minute through a tower of cross-section 4 ft 4 in. by 4 ft 10 in., or 1200 tons per day of solids of specific gravity 2.6 when the pulp density was 65 per cent. Previous tests indicated that a total tower height of about 30 ft would be required for a recovery of better than 99 per cent.

Jan 1, 1969

By J Ledgerwood

Namakwa Sands is a mineral processing company based on the West Coast of South Africa and is solely owned by Exxaro Resources Limited. Mineral ore is mined and processed, concentrated and both chemical and mechanically upgraded before being sent for electrostatic and magnetic separation units. The final high value mineral products report as Zircon, Rutile and Ilmenite.The recovery of non-magnetic material is largely dependent upon a number of factors, including but not limited to dew point, ambient temperature, feed rate, mineral size distribution, specific gravity and mineral content in head feed. One important limiting factor to recovery in typical dry mill operations is the particle size distribution of the feed. Variance in the particle size has catastrophic consequences for recovery. This is the reason for this study. Until recently large variances in non-magnetic production were viewed to be a function of machine operation. This view was later rejected with the feed size distribution determined as the major driver of low recoveries, for Namakwa Sands orebody 50 per cent variance in particle size distribution can be noticed within one day. This is because of the successive mining blending techniques employed.The predicament is that the two modes were so closely placed together that recovery of a single mode is almost impossible without the consequence of greatly reducing recovery. The second mode was found at 125 µm while the first was at 90 µm. Interestingly, for the mentioned feed type a cumulative size distribution of a unimodal feed type is almost exactly the same as for a bimodal size distribution. Thus a plot of cumulative size distribution will show no difference due to the modes being so close together. This is the reason why this phenomenon was not noticed before.The study also found that, using an high tension roll (HTR) or rare earth roll, a fine stream with a single mode at 90 µm versus a coarse stream with a single mode at 150 µm would yield completely different results interms of yields. Larger conductive particles are thrown from the roll while small particles loose charge faster (entrainment). Results in terms of the bimodal size distribution show that even though 25 per cent of the feed type is greater than 150 µm the yields followed a similar pattern to that of the coarse particles rather than that of the majority (75 per cent) fine particles. This confirms what was published by M Ziemski and P N Holtham in 2005 on charge decay rates; they mentioned that particle bed effects played a major role in recovery.

Oct 5, 2011

By A Tsang, D La Rosa, L Julian, W Hunt, R Pratama

Mineral extraction is facing the twin challenges of finite resources and increasing environmental and economic costs. Society’s growth is matched by an increase in demand for the earth’s resources. It is incumbent on us as contemporary mining professionals to promote and facilitate ethical and efficient practices. Technological developments have and will continue to allow a decrease in viable cut-off grades, creating new economic opportunities from deposits that were previously uneconomic. Mining low-grade deposits however, even with perfect recoveries, will have a significant environmental cost for the metal won. The greatest opportunity to increase metal with the least environmental cost is to increase the metal yield from existing mines. The determination of mining polygons is a critical juncture where rock is typically subjected to the binary grading of either ore or waste. This is undertaken using a number of factors, such as the mining equipment being used and the recovery in the processing plant. Traditionally, mining polygons were generated on the in situ grade control model. This ignores the complex differential blast dynamics that occur during blasting. Two opportunities exist to improve metal yields: optimise the blast design to achieve the post-blast muck pile that will support the greatest outcome; and generate optimised polygons on the post-blast muck pile. A data set from a Canadian Gold deposit is used to demonstrate the potential benefit of iterative blast movement modelling and grade control polygon optimisation on metal yield. The impact of blasting on the total recoverable metal is presented, highlighting blast design as a critical process in the mining value chain.

Sep 1, 2024

I once read an æarticleÆ in FHM Magazine entitled æThe Coolest Jobs There Ever WasÆ. It was about a group of guys who were pursuing careers that any person on the planet would just kill for. I distinctly remember drooling over the pages, thinking how much I would love to be Michael SchumacherÆs Chief Engineer at Ferrari, or the Principal Designer and Tester for one of the big Dutch rollercoaster companies. From that moment on, I decided that I wanted a career that was cool enough to make it into the pages of that article. Throughout my time at university, I always had that article in the back of my mind. As a result I constantly wondered about what sort of job I could end up with once I left university. More importantly, I wondered if FHM would be banging down my door to put me in the magazine! After a long and stressful job hunting process (in between completing a thesis and studying for exams) I finally managed to land myself a job with Orica Mining Services. I can honestly say I didnÆt know what to expect when I first joined Orica. Most of my friends ended up working for big mining companies, while I was offered a position with one of the biggest suppliers to these mining companies. However, I had a feeling when I was discussing the role with my future supervisor during the interview process that the job was going to be awesome. I have now spent a year working for Orica and I absolutely love it! While I feel that my job is worthy of being in that FHM article, unfortunately, I donÆt think I am going to get my opportunity to be in the magazine. Apparently I donÆt look too good in a bikini! However, I would love to have the opportunity to discuss the journey that I have taken so far û from my time as an environmental science graduate, then moving on to mining engineering, to now, being part of the Orica Mining Services Graduate Program. My suggestion is to use this paper as a resource. I have learnt during my time at university, as well as my time in the workforce, that the best people you can learn from are your peers. Take what you feel is relevant from the paper; hopefully it will help guide you in shaping your own career.

Jan 1, 2005

By B Reid

"Since the commencement of mining operations at the Cowal Gold Operations (CGO) in 2005, reverse circulation (RC) drilling has been the preferred method for grade control (GC) sample collection. This method was selected because it allowed:for multibench drilling (20 m hole depths for two benches of mining) to aid mine planning increased data density for comparison against the wide spaced ore reserve model angled drill holes to intersect perpendicular to the strike and dip of the shallow dipping mineralisation ability to take two metre sample intervals to enhance the understanding of the mineralisation’s short-scale variability and provide the ability to flitch mine.From June 2008 to December 2013, RC GC was performed using a UDR rotary cone splitter. The field duplicate data over the period displayed strong precision, with a correlation coefficient of 0.94 and an average relative per cent difference (RPD) of 21 per cent for gold. Up to 66.1 per cent of field duplicate data greater than 0.1 g/t fell within ±20 per cent RPD. This is within limits of industry best practice. The Mine to Mill reconciliations over the same period showed the estimated GC grade was 7.7 per cent lower than the calculated head grade (CHG).In December 2013, the Progradex sampling system (PGX) was introduced at CGO due to its advertised ability to capture 100 per cent of the drill cuttings for the complete sample interval, inclusive of fines. Analysis of field duplicate data indicates that since the introduction of the PGX, the sample precision has drifted. From January 2014 to February 2016, the correlation coefficient was 0.92 and up to 51.2 per cent of field duplicate data, greater than 0.1 g/t fell within the ±20 per cent RPD. Over the same 26 month period, the Mine to Mill reconciliation improved to one per cent lower than the CHG. Granulometric analysis of the RC samples collected from the PGX indicated the fines material(<212 µm) averaged up to 22 per cent of the samples mass and following assay determination, the fines material represented a weighted average of 31 per cent of the total gold content within the sample.This paper highlights the:importance of the complete capture of all drill cuttings during an RC drill programinfluence of fines material on the sample quality and accuracyimpact sampling of the fines material has on the Mine to Mill reconciliation performancechallenges experienced in commissioning a PGX system.Citation:Reid, B, 2016. A Fine Looking Sample - the Importance of Fines in Grade Control Sampling to Mine to Mill Reconciliation, in Proceedings Ninth AusIMM Open Pit Operators' Conference 2016, pp 28–38 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 15, 2016

By B Rohrlach, J Gonzalez, A Buenavista

Located on the island of Mindanao in the Southern Philippines, the Tampakan copper-gold deposit represents a major high-sulfidation epithermal deposit superimposed on an underlying porphyry copper system. With a recent JORC compliant indicated and inferred resource estimate of 1104 million tonnes at 0.65 per cent copper and 0.26 g/t gold at a 0.3 per cent copper cut-off grade, Tampakan represents the largest undeveloped copper-gold deposit in Southeast Asia. Since its acquisition by Indophil ResourcesÆ affiliate Sagittarius Mines Inc in August 2002, the deposit is the subject of an ongoing preliminary feasibility study into project viability that is initially focused on a higher-grade copper zone in the north-central part of the deposit. The deposit is hosted by a sequence of subaerial andesitic flows (Tampakan Andesite Sequence) related to a highly eroded andesitic stratavolcanic complex of Pliocene age. Detailed mapping and geochronological dating has identified four volcanic cycles or centres that have been sequentially developed and eroded. This stratovolcanic complex is interpreted to lie on the northern extension of the Sangihe volcanic arc that extends from Northern Sulawesi in Indonesia. The Tampakan district is located within a complex tectonic setting dominated by WNW trending wrench faults that form part of the trans-Mindanao Cotabato Fault Zone. The Tampakan deposit is located near the intersection of one of several WNW trending splay structures with a prominent NNE trending dilational structure, one of many that transect the host volcanic complex. High-sulfidation style copper-gold mineralisation at Tampakan is broadly associated with and central to a flat-lying tabular body of pervasive silica and silica-clay alteration developed within a district- scale lithocap of advanced-argillic and argillic hydrothermal alteration that extends over an area of 90 km2 within the volcanic complex.

Jan 1, 2004

The 3.5 million tones per annum Enterprise mine is the newest underground copper mine at Mount Isa in northern Australia. At a depth of up to 2000 metres, it is the hottest and deepest mine in Australia. In situ rock temperatures sometimes exceed 60¦C requiring the installation of substantial amount of refrigeration to provide safe working conditions for mine workers. The latest refrigeration project at the mine, R67, required the design and installation of the worldÆs largest bulk air cooler and AustraliaÆs largest chilled water plant. The plant is mounted on the surface of the mine and provides 25 MW of refrigeration to cool some 580 kg/sec of ambient air to 11.4¦C. This is equivalent to the production of 6300 tonnes of ice per day. The plant was designed for high availability, as any downtime would result in substantial production losses to MIM, and also had the potential to quickly result in unsafe levels of heat stress within the underground workplaces. The bulk air cooler has been designed for a capacity of 34 MW(R), the expected ultimate carrying capacity of the 7 m vertical intake shaft. Being located well inside the tropics, technical issues such as control of thermal pulldown required special consideration. Also, the bulk air cooler had to be designed to handle whatever demand for fresh air was imposed by the mine below, with over 100 per cent variations in airflow expected, and without loss of thermal efficiency. A substantial program of risk assessment and HAZOP studies was used to protect underground miners from leaks of ammonia into the air or water circuits. Fully automatic control systems result in a totally unmanned plant that is supervised remotely. To improve efficiency, the plant is controlled by the outlet air temperature from the bulk air cooler û the first in the world to be controlled in this fashion. Engineering solutions to address environmental considerations were incorporated at the design stage through features such as the use of ammonia (a greenhouse-friendly gas) as the refrigerant, zero atmospheric discharge and a wastewater collection and re-use system.

Jan 1, 2002

By K Blay, C McCamley, P Petrucci

The Newmont Boddington Gold (NBG) processing plant was designed for 35Mt/y with ball mills expected to deliver a combined new mill feed rate of 4837 tonnes/hr. Since beginning commercial production in late 2009, the plant has steadily increased throughput to meet design capacity in 2014 and reached 37 Mt/y in 2015. Through improved efficiencies, changes to the milling circuit have taken place since commissioning to take the plant beyond its design to an actual throughput of 39.0 Mt in 2017 and a budgeted throughput of 39.4 Mt/y this year.The NBG milling circuit has four parallel ball mills, each consisting of a 7.9 x 13.4 m ball mill with twin 7.5 MW fixed speed motors in closed circuit with twelve 650 mm cyclones. Each mill is fed by two wet screens with the undersize gravitating to a mill discharge hopper where it is combined with the ball mill discharge and pumped to hydrocyclones for classification. The cyclone underflow is re-ground to a target P80 of 150 µm.This paper will focus on process improvements made to the NBG milling circuit which include cyclone reconfiguration, fine screen panel redesign, implementation of an expert control system, mill power draw increase and grinding media changes to take NBG beyond its design throughput.CITATION:McCamley, C, Petrucci, P and Blay, K, 2018. Going beyond design at Newmont Boddington Gold, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 497–508 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

The development of the Moura Coal Preparation Plant is described, commencing with the first'stage of the plant commissioned in 1963. The subsequent expansion stages are traced through to October, 1973. The plant has undergone frequent stages of expansion and modification and this process is continuing. The development programme for 1974 is described as proposed in late 1973. The characteristics of the Moura and Kianga field coal seams with respect to washability are summarised and some comment is made on the blending of these coals prior to washing, to ensure production of export grade coal within specification.

Jan 1, 1974

By A G. L Pratt

The record for autonomous haulage systems in underground mining over the past 15 years is patchy, marked by many trials and attempts, with few examples of sustained operation until relatively recently. The drivers for the introduction of this technology are variously listed as the occupational health and safety of people working in underground mines, reductions in direct operating costs and increases in productivity.This paper reviews the trends for operation of semi-autonomous and autonomous haulage achieved by underground mines and the defining features of the technology currently available. The inclusion of autonomous haulage as part of mining studies and the fundamental conditions for its successful application is discussed in the paper. The components required for an autonomous underground haulage system are outlined and the key aspects that need to support its effective implementation are examined together with their associated opportunities and risks. Special note is made of the critical role people, including executive leadership, have in ensuring the successful introduction of this technology.The paper draws on published case study material, equipment supplier information and research findings. The aim is to offer a high-level insight into what is required for the application of autonomous haulage technology and its successful implementation in underground mines.CITATION:Pratt, A G L, 2016. Autonomous haulage systems in underground mining – what is required for success? In Proceedings International Mine Management Conferenc, pp 35-52 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 22, 2016

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 J K. Claflin, S R. La Brooy, A M. Claflin

Rotary kilns have been in service in the gold industry to regenerate carbon for 65 years. At the time oxide ores with gold head grades of 8 to 10 g/t were being treated. Carbon could be regenerated adequately at 650°C and solution losses were less than 1%. Forty years ago, research indicated that heavily fouled carbon from flotation circuits had to be held at 750 to 850°C for ten to twenty minutes for full reactivation (Avraamides and La Brooy, 1987), gold head grades were typically 5 g/t and solution losses typically 0.02 ppm – still less than 1%. In 2017 it was determined (Claflin et al., 2017) that a residence time of less than 1 minute at 750°C can be adequate to reactivate carbon fouled with organics sufficiently to achieve 0.005 ppm solution losses in a flotation tailings leach plant.With the potential for discovery head grades to drop below 0.6 g/t, solution losses of 0.02 ppm represent over 3% loss. Tight operation of the whole carbon circuit is required to keep gold solution losses below 1% going forward.There are alternatives to a rotary carbon kiln, e.g. vertical kilns of which the Minfurn, Rintoul and Combustion Air kilns are examples. The alternative kilns can be heated using electrical heating elements, induction, and microwave. These kilns can operate successfully under the right conditions, however, they are almost exclusively for small carbon throughputs and are not suitable for the large carbon advance rates that are required to process low head grade ore deposits. Large throughput carbon kilns are are almost exclusively fossil fuel fired rotary kilns and the subject of this paper. In the view of the principal author, a fossil fuel fired vertical carbon kiln is preferred to a rotary kiln, however, it is not currently used in the industry.Thermal regeneration of activated carbon has a major impact on gold recovery in the carbon circuit. The carbon kiln and associated equipment constitute 3 to 5% of the capital cost for an oxide processing plant and up to 10% of the capital cost if flotation tails are leached. Despite the capital cost and impact on recovery, the carbon kiln is often poorly selected, operated and maintained.Six years ago Ausenco embarked on the Carbon Kiln Initiative to reduce solution gold losses. This body of knowledge has been published in a series of papers culminating in this paper on how to:1. Select a kiln appropriate for the flowsheet;2. Maintain the kiln to achieve design operation; and3. Operate the kiln to minimise costs and maximise reactivation.CITATION:Claflin, J K, La Brooy, S R and Claflin, A M, 2018. Carbon kiln selection, operation and maintenance, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 251–274 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018