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By G Reynolds, L Lu

Queensland Pacific Metals (QPM) is developing its flagship Townsville Energy Chemicals Hub (TECH) facility to produce nickel and cobalt sulfates from imported high-grade nickel laterite ore for nickel-cobalt-aluminium and nickel-cobalt-manganese Li-ion batteries. The TECH facility is expected to use a patented leaching, recovery and recycling process called the DNi Process™. It uses the nitric acid leaching process for extracting nickel, cobalt and other valuable metals from laterite ore. Apart from the nickel and cobalt sulfates, the TECH Project will also produce high purity alumina, hematite (~640 ktpa) and other by-products. The hematite by-product precipitated from the DNi Process™ (hematite precipitate hereafter), is high in Fe and particularly low in impurities. QPM is working to identify potential applications for these high-purity by-products to generate additional revenue and to achieve its zero-waste ambition. As such, QPM has engaged CSIRO to evaluate various agglomeration options to produce low-cost, hematitic products suitable as ironmaking feed materials. This paper will first reveal the unique characteristics of the hematite precipitate arising from the TECH Project and then examine the sintering and pelletising processes for preparing the hematite precipitate as an ironmaking feed.

Sep 18, 2023

By M Jacobs

This abstract discusses a heap leach copper mine that was failing to perform and as a result was not meeting targeted production. The mine had numerous technical challenges including: high water inflows, low levels of geotechnical monitoring, performance issues with mining, resource model and grade control reconciliation issues, and unexplained low levels of performance from the heap leaching operations. A team from various organisations with specialist skill sets including: a forensic accountant, the owner’s representative and a mining engineer, was arranged to visit the site. The task was to investigate the situation and determine what could be done to turn the performance of the mine around. After an initial assessment in late 2018, efforts were directed to better understanding the operations and improving the performance of the site through preventative management. A key part included the creation of production forecasts that could be achieved that would help restore confidence in the operations. Uncertainty in the mine achieving production forecasts and the performance of the heap leaching operations were contributing to the decline of the operations. Investigations uncovered the fact that while the resource model could reliably predict total copper, a lack of sequential leach data meant the accurate prediction of soluble and insoluble copper species, both important for heap leaching, was difficult to do with any degree of certainty. The crushing and mining contractors also appeared to have suffered somewhat from a lack of management by the owner’s team and performance had affected the production of copper. Collaboration and management were used by the team to understand and stabilise the operations. Ongoing collaborative efforts by the management team, site personnel and contractors resulted in a positive outcome for the owners and their mine – and could at yours.

Jun 22, 2022

By C D. Rose

"The primary objective of this paper is to demonstrate a different approach to predicting and verifying mechanical sampling system precision. Early in the year 2011 an experiment was conducted to evaluate the sampling precision being obtained by a three-stage falling-stream mechanical sampling system for coal owned and operated by Peabody Energy. This system collects samples from lots averaging approximately 14000 t being loaded onto rail cars at a flow rate averaging about 9000 t/h. In phase 1 of the experiment, a total of 60 increments were collected in a two day period at preassigned intervals using a cross-belt sampler located on a conveyor belt feeding a silo upstream of the sampling system under evaluation. Coal variability parameters were calculated from the resulting laboratory analysis data using the gauge-invariant fractal model developed by the author.Estimates of precision of the three-stage system as a function of the number of increments were calculated using the variability parameters determined in phase 1. In phase 2 of the experiment, duplicate samples of 30 lots of coal were taken by the three-stage sampling system, enabling calculations of the precision being achieved by the system. Phase 2 precision estimates are in reasonable agreement with those of phase 1. Conclusions drawn from the experiment include the following: Experimental variograms or the equivalent correlograms are essential in understanding sampling issues and for designing a sampling system to meet specific precision requirements. Consensus coal sampling standards provided by ISO and ASTM may be improved by treating all stages of a mechanical sampling system as æsamplingÆ rather than considering downstream sampling stages as æsample preparationÆ, to be treated in a separate part of the document. The coal industry would profit from use of methodology for routinely monitoring the overall measurement precision and the precision of the individual components of measurement: sampling, sample preparation and laboratory testing. This would not only give necessary credence to the measurement results but would also no doubt, lead to more efficient sampling system designs.CITATION:Rose, C D, 2012. Evaluation of precision being obtained by a three-stage sampling system for coal, in Proceedings Sampling 2012, pp 115-124 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 21, 2012

By N Clarke, J Hunt, A Barros, L Keeney

The Gramalote orebody is a large low-grade gold deposit situated in the San Roque municipality, 124 km north-east of Medellin in Antioquia, Colombia. It is jointly owned by AngloGold Ashanti (AGA) and B2Gold and is currently in Feasibility Study phase. In 2013 AGA requested CRCORE to undertake a preliminary study of the potential application at Gramalote of pre-concentration by screening, part of the Grade Engineering suite. 160 samples of coarse assay rejects (-3 mm) were tested and showed one of the strongest responses seen worldwide to that time, suggesting that about 70% of the gold could be recovered into 40% of the mass. This was seen as potentially markedly improving the Gramalote economics. A large-scale testing program was implemented on site to follow up these results. A total of 18 samples of 17 t each were mined along a pre-existing exploration adit. A complex test flowsheet allowed size fractions to be generated from the as-received material as well as after crushing to 53, 23 and 3 mm, all from the same head sample. The procedures were designed after carrying out a heterogeneity study to measure sampling errors. The coarser size fractions were designed to study the effect of crushing on upgrade response and predict the response on open-pit run-of-mine ore. The finer size fractions were designed to investigate means of predicting the upgrade response across the orebody. The large-scale testing closely confirmed the average upgrade response as predicted from drill core assay rejects but found that only the -53 mm crushed material accurately predicted the upgrade response of individual samples. Ore geochemistry was able to usefully distinguish samples with good and poor response. A small study on drill core suggested that, for Gramalote, fine crushed material distinguishes vein associated and disseminated values but not other factors that control actual outcomes.

Nov 10, 2020

Mining ventures are essentially risky businesses. Explorers and project developers (plus their investors and financiers) attempt to minimise the risks involved or at least manage them. Core considerations are the obvious technical and commercial risks, but the socio-political system and regulatory environment in which the project will operate can be more important. Successful mineral investments in a country depend upon obtaining realistic and reliable technical results in a country that provides certainty, to gain and maintain investor confidence in a project. Brief commentary is provided on the usefulness of professional accreditation and ethics plus other specific reporting codes (eg JORC/VALMIN Codes) in reducing risks by reinforcing high technical competence and reputable individual professional behaviour (particularly in the context of currently perceived high corruption levels in so many countries). These various risk components are reviewed, especially in a global context, to showcase New ZealandÆs current position. Successful projects are those which provide investors with credible and reliable optimal results in less volatile environments because investors/lenders hate uncertainty and surprises even more.

Jan 1, 2005

Gold was determined directly in eight different mill cyanide solutions, by atomic absorption spectroscopy in an acetylene-air flame. Some of the mill solutions were diluted with water to bring them into the most sensitive absorption region (5-50 p.p.m. Au) whereas those solutions with very low gold content «2 p.p.m.) were concentrated by evaporation.Calcium was complexed with ethylene diamine tetra-acetic acid (EDTA) to avoid the undesirable effect of a precipitate on atomization.When added to standard gold solutions, EDTA had no effect on absorption, nor did any of the impurities common in mill cyanide solutions.Known amounts of gold, ranging from 2 to 30 p.p.m., were added to mill solution'aliquots and recovered to within 100 ± 2·5 per cent. For duplicate determinations under normal worKing conditions, standard deviation was 1·32 p.p.m.Excellent agreement was found between atomic absorption gold values and accurate fire assay values.INTRODUCTIONAtomic absorption spectroscopy has been shown to offer a rapid and accurate method for the determination of trace amounts of a number of metal ions. In the field of primary metallurgy atomic adsorption has been used for routine determinations of lead, copper, silver, zinc, cadmium and iron in a variety of raw materials and intermediate products.The scope of atomic absorption spectroscopy was reviewed recently by Willis (1963).The noble metals silver, gold, platinum, rhodium and palladium were determined by atomic absorption from chloride solutions by Lockyer ·and Hames (1959). In their determination of gold down to 1 p.p.m., they found no interference from the noble metals, nor from considerable excess...

Jan 1, 1964

Two key elements in the design of a pastefill or high density backfill system are the preparation of the backfill material and its distribution underground. This paper examines these two areas. Owing to the essentially impervious nature of total mill tailings, preparation of pastefill and high density fill from current tailings involves a physical dewatering process. There are currently three methods available for this process: Vacuum or pressure filters. These represent the ætraditionalÆ approach to the preparation of pastefill. Paste production storage mechanism. This is a thickening/storage mechanism developed with the specific objective of producingpaste/high density backfills. Fluidization. This system utilises silos fitted with simple dewatering devices and nozzles. Recently developed by CANMET, it provides the simplest and most economical approach.This paper describes and compares the three preparation methods, from a practical and an economic point of view. Once the pastefill/high density fill has been prepared and binder added, the backfill must be distributed underground into the stopes. A fundamental factor in the design of a distribution system is the rheology of the material. No two materials will exhibit the same properties, and a sequence of rheological and related testing is required prior to the completion of the design of the underground distribution system. This paper covers the testwork normally required and discusses the fundamental design parameters of pastefill distribution systems. The final section of this paper summarises the use of pastefill at three mines in Canada.

Jan 1, 1998

By C Parihar, R Garg, A Bhandari, S Bhandari

Blasting can impact the efficiency of entire downstream mining operation. Individual technology solutions for blasting have been available in the industry for many years but all of them only cater for certain aspects of blasting. Many of them are based on individual research and/or experiences. Some of the available software solutions are not suitable to be used in the field as that they need advanced skills or tools. Also, most do not take technology advancements like mobility, advanced data analytics, web solutions and integration into consideration. Hence, no technology platform is currently present in the industry that addresses all potential needs a blaster may need in an integrated manner.This paper presents an integrated solution that takes care of all aspects of blasting – design blasts according to mine plan; collect data after drilling has been carried out (as there is often difference in designed and actual drilled hole locations in the field); predict blast results in terms of fragmentation, flyrock, ground and air vibrations, wave front reinforcement and flyrock distance; and after assessment, allows changes in charging, delay timing and sequence. The technology solution is a secure, cloud-hosted, web-based software-as-a-service solution that can be accessed from anywhere. Also it has a mobile app, which is available for both Android and iPhone/iPad. The mobile app is also integrated with the web-based solution using application programming interface calls to the central data repository.Case studies for two limestone mines are presented where this solution is being used in its initial format. This software platform enabled analysis of the outcome from a previous blast pattern and then subsequently allowed optimisation of blasting operations based on historical data. Uses of this platform have resulted in improved key performance indicators in these two limestone mines. The mobile app as part of this platform enables extensive field blast data capture and analysis and also various predictions before a blast. Data collected include blast parameters, individual hole charging, initiation pattern, videos, photographs and vibration records for analysis/reporting. The key features of the solution are a blast designer, a detailed blast data collection/analysis and a series of environmental predictors. These predictors give blast results in terms of fragmentation, flyrock, ground and air vibrations and wave front reinforcement and take remedial steps before blasting to optimise and control adverse environmental impact. Many features, such as fragmentation predictor and mobility solution, are completely unique features that are not available elsewhere in such a field personnel-friendly manner.CITATION:Bhandari, S, Parihar, C, Garg, R and Bhandari, A, 2015. An integrated technology solution for optimised and environmentally-controlled blasts, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 393–400 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By Q Yang

This paper describes the design and construction of three 7.2 m span access ramp-tunnels to the three level underground car park of the newly redeveloped Top Ryde City Shopping Centre in northern Sydney. The tunnels were to be excavated without significant impact on the overlying Devlin Street, one of the busiest arterial roads in the Sydney metropolitan area and a major link in the Sydney road network. The interpretation of the geological conditions indicated that the tunnels would be driven in a formation of heavily jointed, extremely weathered to fresh Triassic Ashfield shale with some structural features such as dyke, fault and shear zones identified in the available boreholes logs. Both empirical and numerical methods were used to design the tunnels and to predict the ground surface settlements. The design solution, which was influenced by the relatively small scale nature of the work and the current demands on the tunnel construction market, included presupport, initial support and permanent steel fibre reinforced shotcrete (SFRS) lining. The interactions of the driven portals with cut and cover sections and the proposed deep excavation of the new shopping centre were considered at the design development stage and in the construction phase to ensure the safety of the live road. The tunnels have been successfully constructed and are now operational.

Mar 8, 2011

By S J. Schafrik, E S. Gilliland, E C. Jong, J Waynert, C W. Weiss

Two commercially available through-the-Earth (TTE) communications systems were evaluated at an active underground longwall mine in West Virginia. One system utilises magnetic field (H-field) antennae while the other system utilises electric field (E-field) antennae to achieve communication. A large portion of this mine is overlain by an inactive gas-oil field composed of densely spaced wells. This feature provided a unique opportunity to determine the impact of cased wells on both TTE technologies. The following communication modes were investigated: surface to underground, underground to surface, underground to underground and real-time two-way communications. Standard deployments of the TTE systems using the manufacturer’s recommended procedures were able to achieve clear communications between underground and surface locations under certain circumstances. As a result, the design and deployment that will optimise TTE transmissions are unique to each system and to the specific area of the mine. This field study was conducted as a part of a larger multisite evaluation of available TTE systems in an effort to determine their operational sensitivity. The performance of these two TTE systems suggested that one may be preferable over the other depending on the conditions present during deployment.CITATION:Jong, E C, Schafrik, S J, Gilliland, E S, Weiss, C W and Waynert, J, 2015. Pairing magnetic and e-field through-the-Earth communication systems based on mine site conditions, in Proceedings Third International Future Mining Conference, pp 245–252 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

By P Bartlett, K Naidoo

Premier Diamond Mine is planning a new, mechanised, block cave, with a production level approximately 1000 m below surface. A high degree of tunnel damage is expected, due to stress and the relatively low in situ strength of kimberlite. An evaluation of the timing of tunnel excavation, tunnel size and spacing has been carried out to define critical parameters for planning layouts and development schedules. Extensive use has been made of three-dimensional FLAC3D numerical models, calibrated against known rock mass behaviour at 650 m depth, to examine the influence of undercut advance on production level excavations. These were able to represent the effect of stress rotation on tunnels during undercut advance and the effect of an inclined undercut. The analysis has provided guidelines that are possibly applicable to any deep block cave layout. The choice of drawpoint layout is of considerably less significance than the proportion of ground extracted on the production level elevation prior to advancing the undercut. The analysis shows that damage to production development will be potentially severe if it is all excavated prior to advancing the undercut, or is mined directly beneath the undercut face. The development of the main production tunnels alone ahead of the undercut may be feasible, but no breakaways should be put in as they appear to trigger a rapid increase in the severity of damage. The optimal sequence is when all production tunnels are developed at least 10 m in plan behind the undercut, where the induced peak field stress is less than 20 MPa and a maximum support pressure of 100 to 500 kN/m2 is require to contain movement. The assessment showed that the conditions are not significantly improved by increasing drawpoint spacing from 15 m to 18 m. The vertical spacing between the undercut and production level beneath is investigated. Provided production level development is carried out beneath the undercut, there would appear to be little benefit in increasing the vertical spacing between the undercut and production level beyond the current 15 m to 18 m.

Jan 1, 2000

The theme of my address to your Institute, indeed its name, is "The Mineral Industry - What Next?" Knowing that I was required to make four appearances, and not wanting to be too repetitious, I wrote a rather long speech of which I will deliver various sections at different places, with a common introduction. Specific areas I have addressed are "Exploration", "New sources of minerals and energy", and "Mining and metallurgy of the future".

Jan 1, 1984

By J Foo, T Kleinschmidt, B Reynolds, K Kennewell

The consideration of complex supply chains often highlights multiple system bottlenecks that are localised and dynamic – they shift depending on what variability last influenced the system. Using the understanding of a dynamic system model, synergies between items that tackle localised bottlenecks can be understood to generate a suite of solutions. These can be simple solutions, such as a couple of new conveyors placed in series, or more complex ones, including buffer dynamics (capacity, location, behaviour, etc).Each solution in the suite will have an associated uplift in system performance and an associated cost of implementation. Dynamic simulations can address each situation in turn and estimate the projected improvement it would offer. However, these solutions will have different benefits when implemented together, and each solution will give different uplift depending on what other solutions have already been assumed. If the number of solutions is numerous, traditional dynamic simulation analysis becomes the bottleneck, limiting options analysis to the processing power available.This paper will illustrate the use of a new technique applied as part of a capital growth optimisation project with a major iron ore producer. Metamodelling is the creation of a model of a model; in this case study, the focus is on developing a response surface representing the suite of solutions. This can be achieved through a combination of dynamic modelling and an appropriate mathematical process called design of experiments. The result is an approximation surface of the outcomes of the dynamic model, encapsulating interactions between key elements of the value chain.This modelling approach provides a number of advantages compared to traditional dynamic modelling approaches, including but not limited to:early and rapid evaluation of a large range of potential solutionsaccommodation of multiple initial states of the value chainoptimisation of the overall suite of upgrades (down to route-level upgrades) based on business objectiveseasy re-evaluation of outcomes when key inputs such as costs change.CITATION:Kleinschmidt, T, Foo, J, Reynolds, B and Kennewell, K, 2015. Case study of iron ore value chain optimisation, in Proceedings Iron Ore 2015, pp 605–612 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By B McCarthy

Mining has been typified of late as a boom and bust, cyclical industry operating against a steady decline in the size and quality of mineral deposits. Decreasing deposit grades and increasing costs of traditional mining techniques, all in the face of another commodity downturn, are forcing mining companies more than ever before to seek out new and innovative ways to operate. New technologies are emerging to model, control and track resources through the mining value chain, to move material about mines more efficiently, and to identify and separate ore from gangue early in the extraction process.Discovering such technologies however is only the first challenge for mining companies. Actually implementing technological change successfully has proved to be an even bigger challenge. Like for many industries, fulfilling the promised benefits for the expense and timing envisioned, has not been easy when innovative technologies are introduced.Citing the author’s insights and experiences in a number of emerging technologies, this paper explores barriers to implementing technological change in the mining context. Key elements of a change management framework, first developed for implementing mine management systems, are described to give mining executives insight into how they and their organisations can succeed through technology-driven change.CITATION:McCarthy, B, 2016. Successfully implementing technology-driven change in the mining environment, in Proceedings International Mine Management Conference, pp 89-104 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 22, 2016

By T Walkemeyer, R Elliott, D Chang-Martin

Over the past decade, discrete element method (DEM) simulations have seen increasing adoption by the resources sector to inform the design of materials handling equipment such as transfer chutes, bins and hoppers. But, if ‘all models are wrong, but some are useful’ (Box, 1979) what approaches are available to check that a DEM simulation is useful? How to avoid garbage in equals garbage out. This work considers what properties of bulk solid flow behaviour are important to transfer chute simulation. Cohesive bulk solids (such as sticky iron ore fines) can develop sufficient strength to form a stable cohesive arch, this phenomenon is not well predicted by measurements of angle of repose. This work presents a two-part approach to the development of a useful DEM model that can be used to add value to the design and optimisation of bulk materials handling equipment. Part 1 is the calibration of not just one, but a range of material models chosen to envelope the range of anticipated materials that will be handled. This work describes the DEM simulation of a batch of direct shear cell tests to develop material models that can be measured by the same metrics routinely used to characterise the flowability of cohesive iron ore fines. Part 2 of this work describes systematic methods for validation of the transfer chute DEM simulations. The DEM model is only useful if it can adequately represent the typical problems observed within a transfer chute, such as blockages due to build-up and cohesive arching. Proper validation requires good observations. Validation examples of site observations are shown side-byside with simulations to demonstrate the adequacy of the DEM model and calibration approach. DEM simulations have the potential to add significant value by allowing engineers and designers to predict material flow-through equipment based on a range of material properties, allowing for stress testing designs and making iterative improvements.

Sep 18, 2023

By Y Zhang, Z Zhao

The green production of the steelmaking process has urgent requirements for fluorine-free fluxes. In this article, a new solid waste-based slagging flux was applied in the external dephosphorisation test of low silicon hot metal to replace the traditional fluorite-lime dephosphorisation slag. The results showed that under laboratory conditions, the new flux was utilised for smelting low-silicon molten iron with a phosphorus content of 0.10~0.13 wt per cent, the temperature of the molten iron was 1350°C and the slag amount was controlled at 2 per cent. Within ten minutes of smelting, the dephosphorisation rate of the molten iron reached more than 50 per cent. When making slag with new flux, the slag melting time was about 40 seconds and the P2O5 content in the final slag was higher than 8 wt per cent. In the industrial test of a 150 t molten iron ladle, under the same molten iron conditions, an out-of-furnace dephosphorisation test was conducted in the Kambara Reactor (KR) process. The flux material consumption per ton of steel was 8~10 kg. Within 15 minutes of smelting, the dephosphorisation rate of the molten iron was about 30 per cent. During flux slag making, the slag melting time was about three minutes and the P2O5 content in the final slag was higher than 6 wt per cent. This new solid waste-based flux has significant cost advantages and outof- furnace dephosphorisation effects and is expected to become the benchmark for a new generation of fluorine-free steelmaking fluxes.

Aug 21, 2024

By J M. Shekiro

In the chloride process to manufacture TiO2 pigment, feedstocks containing higher TiO2 contents (high-grade ores or HGOs) are favoured in order to minimise production of undesirable by-products. Most of today’s HGOs are produced through the smelting or reduction and leaching of ilmenite, processes which consume significant energy and/or produce large volumes of non-titanium materials that may have to be landfilled. In order to improve the economic and environmental sustainability of its TiO2 business, the DuPont Company, working with Kobe Steel Ltd, has developed an innovative process called TiRON for making HGO. Using a rotary hearth furnace, the process reduces ilmenite to a high TiO2 slag and metallic iron granules. The TiO2 slag is suitable for TiO2 pigment manufacture, and the iron is suitable for steel making. TiRON can process sand or rock ilmenite of varying compositions and particle sizes. Fossil fuel instead of electricity supplies the energy for the reduction. Dusts and off-spec materials are recycled. These process attributes, together with capital requirements estimated to be significantly lower, give TiRON substantial economic, environmental, and process flexibility advantages over conventional ilmenite upgrading processes. TiRON has been demonstrated at the semi-works scale, and preparations are being made to bring it to the pilot scale.

Oct 5, 2011

By R A. Pax, B Cornish

"Although it is well known and easily experienced that the feed size distribution influences the throughput and stability of operation of a semi-autogenous grinding (SAG) mill, the details are poorly understood since it is often only the input and output measurements that are used to identify unfavourable in-mill conditions. Load cells and power monitoring are sometimes used but are generally poor indicators of the mechanisms that lead to such unwanted conditions.At the MMG Century operation a 12-microphone array around the SAG mill using non-contact acoustic measurement methodology has been used to diagnose the in-mill conditions to facilitate improved throughput and stability of operation. Use of acoustic measurement and control has provided a demonstrated increased throughput of at least 20 per cent as well as improved stabilisation of the mill. Since the information derived from the acoustic noise from a mill allows discrimination of the behaviour of the steel balls and the rock, a number of in-mill conditions can be identified with signals that include toe and shoulder angles, water holdup and the ball to rock ratio.Feed size variations, measured online with an imaging system, have been used to determine their effect on the internal charge behaviour. It has been found that circumferential segregation of steel balls and rock occurs as well as poor mixing of large rocks. Both of these effects are not conducive to optimal breakage rates of different size fractions. Longitudinal segregation effects also occur. This paper presents and discusses these results and illustrates how the new acoustic knowledge can be used to manage and improve mill operation and stability.Citation:Pax, R and Cornish, B, 2016. Understanding Size Effects of Semi-autogenous Grinding (SAG) Mill Operation as a Pathway to Solving Feed Disturbances - Case Study using the MMG Century SAG Mill, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 321–330 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

The Australian coal industry has undergone sevenfold growth over the last 30 years and since 1985 has been the world's largest coal exporter. Three quarters of Australia's coal production is exported so its future is dependent on it remaining internationally competitive with other energy sources and other coal exporting countries. Coal is likely to increase its share of the energy market during the nine- ties as oil prices increase, new coal-fired capacity is commissioned and some form of nuclear energy is developed which is of acceptable safety standards to the community for use in the 21st century. Gas may take a part of coal's anticipated market share by the Year 2000. While coal exports will increase from China, Colombia, Indonesia and Venezuela and satisfy some of this additional coal demand Australia will also expand its export production, due to its existing advantages. The United States, Canada, South Africa, Poland and USSR seem unlikely to enjoy the same degrees of expansion and some, particularly Poland and USSR, will decline. Australia will always find it difficult to compete in the more distant markets due to levels of ocean freight, although its high quality coals will tend to partly offset such disadvantage.

Jan 1, 1988

By M J. Thurley, L Lindqvist, D Degerfeldt, J Nyström, R Nordenskjöld

Rock breakage is a major component of all mining and mineral processing operations with the particle size distribution linked to productivity through the comminution chain. Optimisation and automatic control of comminution, material handling, and agglomeration processes is a complex task with large potential for gains in productivity, and energy efficiency. A key factor in realising these gains is the requirement for fully-automated online particle size distribution measurement to provide the necessary feedback and input for control. Moreover, to enable automatic control system it is necessary to provide a consistent, reliable size distribution measurement that avoids the significant errors resulting from under-sizing overlapped particles and over-sizing clusters of fine particles. Published literature and observation of commercial systems indicate a body of predominantly 2D photographic based particle size measurement systems that suffer from a number of significant errors except in the simplest case of a monolayer of particles under good illumination with limited colour variation in the material. In order to overcome these limitations a university and industry collaboration developed three-dimensional particle measurement (3DPM) between 2006 and 2012, based on 3D surface profile measurement of the visible material on conveyor. 3DPM avoids particle delineation errors due to variation in material colour and shadows, detects overlapping versus non-overlapping particles, and identifies areas of fine particles as fines and not large rocks. 3DPM measures: the visible material and calculates its particle size distribution, bulk volume, detects boulders, and conveyor belt fill factor in an automated consistent manner. Furthermore, 3DPM’s advanced algorithms allow observation of particle variation that would otherwise be undetected without the capacity to identify visible areas-of-fines and overlapped particles. Boliden Mines has installed 3DPM at three operations for measurement between the stockpile silo and grinding mill, and measurement after the primary crusher. Fragmentation measurements across multiple years of measurement are presented with some observations of plant behaviour. In the future 3DPM results will be incorporated into automatic control strategies for plant optimisation. 3DPM is used across a wide range of material types and applications that also includes; limestone aggregate for quality control in manufacturing, agglomerates for closed-loop automatic control in chemical production, and measurement of coke for size-based blending feed control to the blast furnace in steel production. CITATION:Thurley, M J, Degerfeldt, D, Nyström, J, Nordenskjöld, R and Lindqvist, L, 2018. Automated, online measurement of bulk material size distribution on conveyor using 3D profile imaging at Boliden Mines, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 641–652 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018