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By P Vass, C Butler, J Condon, B Hooper

DeGrussa Copper Mine, resource status 10.2 Mt at 5.7 per cent Cu, 2.1 g/t Au (Sandfire Resources, 2013), commenced concentrate production through its 1.5 Mt/a conventional copper flotation processing plant in September 2012. Geometallurgical assessment during the feasibility study identified potential process-critical ore factors that required further investigation to determine potential impact on processing. Ore characterisation and metallurgical processing performance test work of ore types ensued and subsequently, the first quantitative DeGrussa geometallurgy model was born. Now one year into steady state production, the geometallurgical program has evolved significantly from its infancy and provides valuable insight into ore characterisation and behaviour in the processing plant. This paper details geometallurgical investigations undertaken at DeGrussa to date; from feasibility metallurgical test work through to geometallurgical modelling and management practices, as well as reconciliation between observations at feasibility study level and subsequent observations in production.CITATION:Condon, J, Butler, C, Hooper, B and Vass, P, 2013. DeGrussa Copper Mine, Western Australia - feasibility to first production: a case study in developing a working geometallurgy model from first principles, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 59-66 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

By X Y. Ma, X G. Tian, P F. Zhang, T B. Zhao, Z H. Li, Z Y. Fu

This study analysed the fracture characteristics and movement process of goaf roofs under the condition of gangue backfilled mining, based on the engineering conditions of Tangshan Mine F5001 gangue backfilled working face. The inclined borehole detection method is adopted to conduct long-term and fixed-point detection of the roof stability. The distribution characteristics of mining-induced cracks in the roof are described quantitatively based on the crack density, and a similar model test method is used to assist the analysis of the roof movement under the control of gangue backfilled mining using stress sensors and digital speckle deformation field monitoring. The results show that under the condition of gangue backfilled mining, structural cracks in the roof typically appear at the boundary of rock strata. The appearance of cracks is related to the rock strata where they are located. Structural cracks appear in the form of single cracks ahead of the working face and develop into structural cracks in the goaf. The roof movement of the coal seam develops in five stages: fracture incubation, crack extension in advance, dense fracture development, steady fracture expansion, and roof stability. Separation forms the primary component of the roof subsidence, accounting for more than half of the subsidence value. The separation generally extends over a long distance along the strike, and vertical crack-intensive areas appear in the roof above the cut-off and stop line. The findings of this study provide a theoretical basis to support designs of backfilled mining and upgrading of hydraulic supports in working faces.

Nov 29, 2022

By O Bøckman, E Thisted, K H. Esbensen, U Thisted

Process industry measurement systems, once installed, are often interpreted as static black boxes delivering correct values as long as not proven otherwise. After first implementation and set-up with a distinct sampling frequency, they often run ‘forever’ without checking if this frequency is still appropriate with respect to changed raw materials characteristics, different process conditions or changed customer specifications. Failure detection is based on operator experience and skills (often close to an art form) and/or from control measurements of reference samples. This may well be too late for many industrial process contexts. An appropriate sampling frequency is a critical success factor for valid monitoring and control.Based on the methodology of variographic analysis we here illustrate how to design/re-design/optimise an industrial measurement system in terms of sampling frequency, discretisation and accuracy based on customer specifications. We also show how variographics can be used to monitor for deviations. We use experience from process industry to show how these methods can be used not only for product characterisation, but also for monitoring input factors, process indicators and measurement of these. The information hidden in the vast amounts of data that is continuously created in modern process industries can be utilised to cut costs in the measurement activities and at the same time contribute to early error detection. We illustrate by case examples from production processes at a nickel refinery, supporting the Lean and Six Sigma methodology. This will provide a standard operating procedure for monitoring the stability of measurement systems, and provide a basis with which to discuss how a variographic approach can be integrated with the Lean and Six Sigma approach as an online tool to map, characterise and validate measurement systems and thus avoid more cumbersome measurement system analysis in full detail.CITATION:Thisted, E, Thisted, U, Bøckman, O and Esbensen, K H, 2017. Variographic case study for designing, monitoring and optimising industrial measurement systems – the missing link in Lean and Six Sigma, in Proceedings Eighth World Conference on Sampling and Blending , pp 359–366 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

The celebrations which took place in 1986 to mark South Australia's Jubilee 150 served to focus attention on all aspects of the State's heritage. Until that time the sites and relics of South Aus- tralia's early mines had been generally neglected. Marked by the ruins of enginehouses and littered with the remains of the massive technology of the Industrial Revolution, these sites have now been recognised as containing the threads of a fascinat- ing story. In the early days of settlement the economy of the Colony was based on land and farming. Droughts caused periods of economic depression which were alleviated by chance discoveries of gold, lead, silver, and copper ore. Some of the mines which were opened on the copper deposits were the largest in the world at that time and their names well-known throughout mining circles. Working by hand with primitive equipment, the early miners excavated vast networks of shafts and stopes often extending to great depths: at Moonta- Wallaroo Mines for example workings extended to 860 m below ground. Because of the presence of underground water, mining to these depths would not have been possible without the Cornish pumping engine. Operated by steam power these massive engines and their associated equipment were transported from Cornwall by clipper and delivered to the mines by bullock cart. At this time the engines were at the peak of their devel- opment and, although expensive to import and install, they were highly reliable: the engine oper- ating Hughes pump at Moonta worked continu- ously for sixty years without a major breakdown.

Jan 1, 1987

By P M. Hetherington, M P. Murphy, K E. Crook, F Pym

Resource characterisation is critical for informed decisions in both strategic and operational space. The sources of information for resource characterisation are limited by: direct measurement of resource attributes, such as grades, rock-types, mineralogy, and are available only from sparse locations, ie drill holes; or indirect geophysical measurements such as seismic, gravity or electro[1]magnetic survey. Data collection tools, methods, and processing technologies are constantly improving providing a broad spectrum of options for data collection strategies. The cost of each data survey varies from thousands to millions of dollars with the value of each additional data having diminishing return for a particular business decision. The value of information analysis provides the optimal decision on data collection strategy within a limited available budget. This work presents an example of value of information analysis for new Blast Hole Assay Tool (BHAT) and Reverse Circulation Grade Control (RCGC) data used in addition to the wider spaced exploration data. The value of information is quantified in terms of reduction of grade uncertainty, ore loss and dilution by comparing different combinations of data collection methods. Four different strategies were considered: exploration samples in addition to 50 per cent of blastholes surveyed with BHAT, exploration samples in addition to 33 per cent of blastholes surveyed with BHAT, exploration with wide-spaced RCGC data, and exploration without additional grade control. For each strategy the observed values have been simulated using advanced multivariate geostatistical simulations and compared with simulated ground truth models. The calculated uncertainty, ore loss and dilution informed the optimal data collection strategy. Opportunity to reduce sample density from the nominal 50 per cent of drill holes was evaluated.

Mar 22, 2022

By S Roberston, G Batt, R Shanahan, B Shah, A Trench, H Bromfield

The geographic imperative of ore systems leaves mining, more so than virtually any other aspect of modern industry, heavily dependent on obtaining and maintaining social licence to operate. A prospective miner cannot arbitrarily walk away from a deposit in search of more favourable community perceptions – concentrations of mineral endowment represent highly specific and fixed elements of the landscape, and their development and extraction thus requires the acceptance and trust of a specific network of landholders and stakeholders, sometimes with diverse and even competing interests in the development and use of the local environment. Weakness or absence of such social licence can bring added costs and complexity to developing and operating a mine – and in extreme cases even result in project failure. Because it must be maintained throughout the life of a project, such social risk becomes a substantial part of overall project risk profile, particularly during routine operations once initial technical and development risks have been largely resolved.CITATION: Bromfield, H, Roberston, S, Shah, B, Shanahan, R, Trench, A and Batt, G, 2018. On equitable distribution of mining wealth and the social licence to operate imperative – an African case study, in Proceedings Complex Orebodies Conference 2018, pp 6–7 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By M C. Ackland

The Grande Côte Mineral Sands Deposit (GCMSP) is located on a coastal mobile dune system in Senegal on the west coast of Africa. Senegal is a stable, democratic republic, having gained its independence from France in 1960. It has a population of about 12.5 million people. The dunes begin about 25 km north-east of Dakar, the capital city of Senegal, and extend northwards for more than 140 km. The mineralised dune system averages about 2 km wide with some areas extending to up to 4.5 km wide.Mineral Deposits limited (MDL), a Melbourne-based company with over 60 years operational experience in mineral sand mining in Australia, holds, through its Senegalese subsidiary MDL Senegal SARL (MDLS), a 25-year Mining Concession covering the deposits. The main heavy mineral (HM) areas identified to date are, from south to north, Mboro, Fass Boye, Diogo and Lompoul. Within the Mining Concession there is potential to identify additional resources beyond the limits of present drilling. The dunes are mobile or semi fixed, pale yellow in colour and overlie older white marine sands. The dunes range between 5 m and 30 m in height and the mineralised zones, which are essentially flat-lying, average around 15 m in thickness. The mineralisation consists, principally of ilmenite with accessory zircon, rutile and leucoxene. Zircon and ilmenite are the main commodities of interest.Independent consultants AMC estimated mineral resources for the four main deposits in 2006 of 1330 Mt of sand averaging 2.0 per cent HM at a cut-off grade of 1.5 per cent HM. At a cut-off grade of one per cent the resources were 3200 Mt averaging 1.5 per cent HM. All of the estimate was classified as Inferred Resources under the 2004 Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves (JORC, 2004).Subsequent completion of infill drilling, sampling and assaying of the initial mining area, centred at Diogo, was completed in 2008, enabling a final dredge path to be designed and ore reserves estimated, based on a JORC compliant Measured and Indicated Mineral Resource. Infill drilling is continuing in the Lompoul and the results of this campaign will be included in the JORC compliant data base by AMC in April 2010 to enable the 15 per cent year dredge path and mine plan to be finalised.Development studies have shown that the project can be optimised as a dredging operation, with mineralised sand being treated in a conventional floating spiral preconcentrator, wet concentrator and dry mineral separation plant. Engineering work now substantially completed by Ausenco Limited (Ausenco) has developed the combination of some existing plant from MDL’s past operations, and new plant for the complete process from dredging to final product separation and grading. Testwork on a series of bulk samples has determined that the project can yield a high quality zircon product and an ilmenite product along with minor rutile and leucoxene.Work to date indicates a likely output of around 80 000 t of zircon in various quality streams (Primary, Secondary, Standard and Foundry Grades), around 550 000 t of ilmenite plus around 15000 t of rutile and around 12 000 t of leucoxene/secondary ilmenite. Planned zircon output would represent around 7per cent of the total world production, which would make the GCZ&IP a significant producer on a world scale.The studies have indicated capital costs to be in the range of US$400 M total operating cost (after completion of ramp-up) of around US$50 M - $55 M/a. Revenue is expected to be in the range $127 M - $157 M/a.

Oct 5, 2011

By L Dubron

This study details a mineralogical and textural characterisation of West African iron ores with an emphasis on their behaviour during mineral processing. By means of both qualitative and quantitative characterisation, a simulation of the beneficiation process applied to these iron ores is performed. A series of different analytical tools are used, including:X-Ray Diffraction (XRD) for qualitative mineralogical analysis;• qualitative optical microscopy (phase identifi cation, description of micro-textures) and (semi)• quantitative optical microscopy (counting of particles, phases and textural types); and• chemical analysis.All the information provided by these analytical methods are combined into a quantitative mineralogical and textural analysis, here called ‘modal analysis’, which enables us to simulate the capability of West African iron ores to be benefi ciated by magnetic and gravimetric separation techniques.On one hand, both qualitative XRD and optical microscopy have revealed the presence of the following mineralogical phases: magnetite, haematite, goethite and quartz. On the other hand, the chemical analyses provide us with quantitative inputs expressed as oxides. We have converted the oxides into mineralogical contents expressed as magnetite, haematite, goethite and quartz. In this way, we build a simple quantitative mineralogical analysis.Beside this, the semi-quantitative approach of the characterisation by optical microscopy also provides us with a liberation study, enabling us to split the gangue-bearing content between two types of particles:1. liberated gangue-bearing particles, and2. composite particles composed by both iron (oxhydr) oxides and gangue-bearing minerals.We have assumed that we could anticipate the behaviour of these two kinds of particles through a mineral process, by simulating the removal of at least the liberated particles of gangue. Optical microscopy also revealed a trend in the weathering profi le of the Tokadeh ore horizon with a decrease from bottom to top of magnetite and an increase of both goethite and martite showing a higher level of oxidation and hydration in the upper ore horizon.We have applied this removal extent upon the quartz content of the mineralogical quantitative analysis and we have re-calculated the quantitative mineralogical analysis considering the expected decrease in the quartz content. Finally, by converting the re-calculated (oxhydr) oxides contents into iron grades and summing them, we do obtain a fi nal simulated iron grade for the upgraded products.

Jul 11, 2011

By M Recabarren, A Echeverria, J Ronda, J I. Guzman, R Dodds, G Juarez, E Vila-Echague

A strategic mine plan is a fundamental part of any mining operation. It must provide a realistic and operative extraction and processing schedule, and yield the highest value for the business. For open pit mines, the problem can be modelled as a set of blocks representing the deposit, for each of which we need to decide if it is going to be mined, if so, when and where it will be sent (process, stock or dump).This problem can be proven to be of NP-Hard complexity. The traditional approach used by mining engineers to tackle this complexity is to separate the problem into more tractable components, solving each separately. The first step is to use the Lerchs-Grossman (LG) algorithm to obtain the final pit limit, as well as a set of optimised pit shells (nested pits), using different input prices. Then, using this input, operational phases are designed. Third, the set of phases can be used as an input for a phase-bench style optimisation, usually using a mathematical programming-based algorithm.There are, however, several problems with this approach. First, dividing the problem into simpler parts has the consequence that any compromises made at early stages limit the potential value left for the following steps. Second, LG is a static algorithm, with no concept of the time-value of money, capacity limits, opportunity costs, etc. Phase design is essentially a manual step, for which nested pits provide insufficient information in practice, and therefore the quality of the result in terms of potential net present value (NPV) depends strongly on the experience and expertise of the designer. This means that key input data such as commodity prices, different processes capacities and mine movement limits, are considered only at scheduling, when there is little room for optimisation. This sequential approach limits the potential value in each step, where a simplified problem is addressed, instead of addressing the real, and more complex problem, which is dynamic and should be solved as a whole.We present in this paper an algorithm, and its commercial software implementation, that addresses the dynamic problem as a whole, simultaneously and automatically creating a high-value strategic mine plan that adheres to basic operational constraints, determining dynamic cut-off grades and delivering a set of phases which can serve as a much stronger guide than nested pits for the final design. We discuss some of the key elements of the algorithm and propose a new methodology for strategic mine planning, where phase design dynamically responds to mining strategy definition. Results using different mining and operational parameters on a fictitious copper deposit are used as a demonstrative example.CITATION:Juarez, G, Dodds, R, Echeverria, A, Guzman, J I, Recabarren, M, Ronda, J and Vila-Echague, E, 2014. Open pit strategic mine planning with automatic phase generation, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 147–154 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By J R. Ruiseco, D La Rosa, L Julian, W Hunt

The DeGrussa copper-gold deposit is located 900 km North of Perth. Copper-gold bearing massive sulfide lenses occur in lower greenschist facies meta-sedimentary and mafic volcanics of the Bryah Basin. Regional folding, faulting, and tilting of the stratigraphy primarily occurred during the Capricorn Orogen (Johnson, 2013). The Shiraz Fault and Merlot Fault are regional oblique-sinistral faults that offset the DeGrussa massive sulfides lenses into three fault blocks by ~350 m and ~120 m, respectively. A network of deposit-scale brittle-ductile faults splay from, and in one example are cut by, the Shiraz and Merlot faults. This results in localised ore displacement, selvage alteration and degradation of the rock mass integrity. Historically, only the Shiraz and Merlot Faults were modelled and validated during mining and grade control. The requirement for a comprehensive structural model became more relevant as mining became advanced and confining stresses on local rock mass became more complicated. The DeGrussa Structural Model has been developed to delineate areas of structural complexity and is an important tool in mitigating rockfall risk through well informed technical design. During this process, every accessible excavation was walked and structurally mapped. New workflows in Leapfrog Geo and new technology, including an app that runs on mobile phones streamlined the validation process. Drill hole orientation was a limiting factor during validation. At the time of writing this submission, the DeGrussa Structural Model consists of 34 faults, and is now an important tool for the Technical Service team when developing mine plans and schedules. Applied structural geology is often seen as exclusive to those with a PhD in the field. Faults at DeGrussa have been modelled and reconciled by a Mine Geologist and Geotechnical Engineer, using first principles geological characterisation. This is a simple process that demonstrates any geologist can contribute to a structural model, provided they understand the fundamentals of unbiased structural measurements and consistent record of observation

Mar 22, 2022

By M Bettison, R Wright, N Taylor

The primary mine planning focus during early study phases of future mining projects is Life of Asset ore production and grade quality, this will always be the situation. While waste schedule optimisation is generally considered in the latter study phases nearing execution for a limited number of schedule periods only and not a true optimisation considering all attributes such as waste destination location, design, cycle time and closure. This can be particularly applicable in large multi-pit bulk mining operations where one approach to meet Life of Asset ore tonnes and grade targets has been to maintain pit development flexibility resulting in large open pit areas and substantial expit Overburden Storage Area (OSA). The value opportunity is to develop a Life of Asset waste schedule source-to-destination optimisation prior to mine development considering all applicable attributes and routinely review throughout the Life of Asset taking account of improved ore and waste knowledge.CITATION:Taylor, N, Wright, R and Bettison, M, 2018. Utilising mine planning to deliver closure landforms through productive movement, in Proceedings Life-of-Mine 2018, pp 96–99 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By J Theiler, B Beamish

The presence of reactive metal sulfide minerals in waste rock contributes to the hazard of spontaneous combustion in dumps, as these minerals react with air and water entering the dump at ambient temperatures to form various mineral products and significant heat. This reaction series can also be an initiator of self-heating of carbonaceous material present in the waste rocks if sufficiently high temperatures are reached. Characterisation of these reactive minerals has primarily been to assess the risk of acid mine drainage, which is not necessarily an indicator of spontaneous combustion risk. No systematic testing procedure has been adopted by industry to assess the spontaneous combustion propensity of the waste rock. As a consequence, the principal management strategy for spontaneous combustion has been a reactive approach of dealing with events as they arise.Recent advances in adiabatic oven-testing have enabled more definitive assessment of the spontaneous combustion propensity of coals, including the quantification of the accelerating influence of reactive pyrite (Beamish and Beamish, 2011, 2012; Beamish, Lin and Beamish, 2012). This same test procedure has been used to assess the self-heating performance of metal concentrates and is therefore amenable to assessing the metal sulfide oxidation process from low ambient temperatures. The data obtained from such testing can be used to quantify the more prone waste rock sequences of a mineral deposit in advance of mining. This enables appropriate management planning for emplacement and long-term storage of waste rock in dumps.CITATION:Beamish, B and Theiler, J, 2016. Characterising the spontaneous combustion propensity of waste rock, in Proceedings Life-of-Mine 2016 Conference , pp 93–96 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By Z Li, D Chalmers, J M. Tenney

This paper presents the findings and analysis of the investigation of effectiveness of thin spray-on liners (TSLs) as a gas management tool in underground coalmines. The project involves spraying TSL on the area surrounding gas drainage holes whereby the TSL acts as a thin membrane decreasing the permeability of the coal. This restricts air migrating through the coal seam and diluting gas from the drainage holes. There are a number of potential benefits from this technique but key points are that gas drainage holes produce gas with higher concentrations of methane. The design and execution of a field trial to investigate the effectiveness of a TSL on purity of in situ methane from gas drainage holes is presented in this report. For eight drainage holes, the results show an average increase in methane purity by 9.14 per cent and a reduction in air contamination by an average 7.93 per cent. Overall methane flow rate decreased by 27.6 L/s; however, flow rates were unreliable due to poor measuring equipment. For most holes, methane purity was not changed significantly; however, certain boreholes were responsible for most of the variation in methane purity. The boreholes showing a dramatic improvement in methane purity were likely those with intersecting cleats covered by the TSL. If the TSL was sprayed over more area, specifically in areas where the cleats are intersecting with holes, it is likely that purity of methane in the drainage holes will increase.CITATION:Tenney, J M, Chalmers, D and Li, Z, 2015. Thin spray-on liners potential in reducing dilution of in situ gas in underground coalmines, in Proceedings The Australian Mine Ventilation Conference, pp 323–328 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By B Rusk, L Corriveau, P Emsbo, R P. Xavier

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Porphyry-Cu (Mo-Au) deposits and iron oxide-copper-gold (IOCG) deposits are both characterised by the presence of abundant halite-saturated fluid inclusions that reflect the circulation of hyper-saline hydrothermal brines. While it is widely accepted that brines involved in the formation of porphyry copper deposits derive from unmixing of moderate-salinity, intermediate-density fluids that exsolve from crystallising magmas, the source of brines that form IOCG deposits remains enigmatic and intensely debated. In this extended abstract, we summarise the fluid inclusion characteristics of both deposit types and present trace element compositional data for halite-saturated fluid inclusions from both porphyry copper deposits and IOCG deposits from around the world.While both deposit types typically contain halite-saturated fluid inclusions, vapour-rich fluid inclusions in IOCG deposits are less common than in porphyry deposits and evidence for fluid immiscibility is rare. IOCG deposits also typically lack intermediate-density fluid inclusions that characterise the deeper quartz-rich veins in many porphyry deposits. Many IOCG deposits contain CO2-only fluid inclusions, a type of fluid not observed in porphyry Cu deposits.Our fluid inclusion compositional data show that most porphyry Cu (Mo-Au)-related brines are dominated by Na, K and Fe and contain elevated concentrations of Ca, Cu, Pb, Zn and Mn up to around the one per cent level. On the other hand, IOCG brines are Na-Ca-Fe-dominated and typically contain far less Cu, Mn and Zn than porphyry brines. In addition to Ca, these fluids are also strongly enriched in Ba and Sr relative to porphyry-related brines. Such compositions are consistent with extensive fluid-rock interaction and/or an evolved sea water contribution to IOCG brines.A sea water or basinal brine source for IOCG brines is further supported by bromine concentrations that are much higher than is characteristic for porphyry-related brines. Porphyry brines have Cl/Br molar ratios of between 800 and 3000, which is characteristic of primary magmatic brines, whereas the Cl/Br composition of IOCG brines is more variable. For example, Na/Cl/Br ratios of most IOCG deposits in the world-class Carajás district fall on or near the sea water evaporation curve (most Cl/Br molar ratios are between 200 and 1000) and are diagnostic of sedimentary bittern brines. A few of the deposits in this district also show evidence of the input of subordinate amounts of magmatic brine. At Ernest Henry, in the Cloncurry district of Australia, most Cl/Br ratios plot close to the sea water evaporation curve, but Cl/Br ratios of up to ~5000 in several samples suggest the input of lesser amounts of magmatic fluids, and possibly evaporite-dissolution-derived fluids. Taken together with geologic constraints, these data strongly suggest that porphyry-type deposits form from the circulation of dominantly magmatic fluids, while IOCG deposits form from large-scale circulation of high-salinity fluids sourced dominantly from sedimentary basins with variable input of magmatic volatiles.CITATION:Rusk, B, Emsbo, P, Xavier, R P, Corriveau, L, Oliver, N and Zhang, D, 2015. A comparison of fluid origins and compositions in iron oxide-copper-gold and porphyry-Cu (Mo-Au) deposits , in Proceedings PACRIM 2015 Congress, pp 271–280 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By A Specht, A Müller, V Montenegro, S Winkler, E Klaffenbach, A Schmidt

In the process of primary copper smelting in flash smelting furnace (FSF), the ratio of iron to silica (Fe/SiO2 mass ratio) primarily determines the slag viscosity and magnetite formation. Viscous slag does not only cause difficulties in daily operation, such as in tapping, it also increases the copper losses to slag. Thus, keeping the Fe/SiO2 mass ratio at the desired level is an important aspect of FSF and slag cleaning furnace (SCF) operation. In this study, the improvement of the Fe/SiO2 mass ratio was conducted in two steps: First, the optimal Fe/SiO2 mass ratio was derived based on thermodynamic data. Based on this analysis, appropriate control limits were determined. Second, this range of favourable Fe/SiO2 mass ratios was implemented into operation by an advice-based control system, which suggests the addition of silica based on the analysis of SCF slag. As this approach was successful, the same advice-based control system principle was adapted for the coke addition to the SCF. After testing the new advice-based control for several months, the production data confirm the predictions by thermodynamics: since the prediction was implemented as an advisor, the copper and magnetite content in SCF slag is significantly reduced and viscous slag is reported less often by operations.

Aug 21, 2024

By F Faraj, M Pal, M Haest, M Bradshaw, H Lang, K Hume

MineSense Technologies Ltd. is revolutionising grade control at mining operations by installing ShovelSense® sensors on buckets that measure the grade of every load before it is dumped in the truck. This allows the mine to exploit grade variations at a resolution that was not available before, reducing the amount of ore loss to the waste stream and removing waste from material destined for processing. These changes dramatically improve the profitability and sustainability of mining operations. ShovelSense relies on X-ray fluorescence analysis of the rocks as they flow in the bucket and is integrated with fleet management to direct the trucks to the right destination. Lab simulations of ShovelSense measurements on porphyry copper ores show correlations between predictions and lab measurements at 0.98 r-squared with a coefficient of variation of 10 per cent. Visualisation of copper grade predictions in three dimensions shows a reasonable match with the dig plan, but with local changes in the ore-waste contact due to more accurate contact identification, related to blast movement and other mining factors. Correct delineation of these contacts ensures ore trucks are not sent to the waste dump and waste trucks are diverted from the crusher, creating enormous value for the operation and the environment.

Mar 22, 2022

By J Heyes, G A. Maddocks, R J. Stewart, G D. Corder

Mining is an international business and vital contributor to national and global economies. It depends on the trust and confidence of investors and stakeholders for its financial and operational well-being (Committee for Mineral Reserves International Reporting Standards (CRIRSCO), 2016). The Social Licence to Operate (SLTO) is an increasingly multifaceted and multistakeholder risk that can impact investment decisions. Community challenges to broader political and economic decisions have given rise to protest delaying or stopping projects or closing mines and has led to loss of life (Ernst and Young, 2016). Some governments are now giving greater powers to stakeholders to make the final decision on approving mining and metals activities (EY, 2016). With billions of dollars in project investment at stake, ongoing engagement, collaboration and effective communication with stakeholders is crucial and mutually beneficial solutions are increasingly expected (EY, 2016). It is therefore essential that the industry communicates the risks (and opportunities) associated with investment effectively and transparently in order to earn the necessary level of trust with investors and stakeholders to underpin its activities (CRIRSCO, 2016). Despite this need, investor and stakeholder trust in the sector has eroded in recent years.CITATION:Maddocks, G A, Corder, G D, Heyes, J and Stewart, R J, 2016. The social licence to operate and drivers for change – resource reporting and mine material characterisation, in Proceedings Life-of-Mine 2016 Conference, pp 183–187 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By P Swart, A Fletcher, P D. Erskine

Glencore Coal Assets Australia (GCAA) operates five coalmines in Queensland and has rehabilitated thousands of hectares of mined land across these sites. Accordingly, GCAA seeks to continually improve rehabilitation outcomes over time and work towards progressive rehabilitation sign-off. The ultimate test of rehabilitation success is the attainment of an agreed land-use target, whether for biodiversity conservation or some type of agricultural production, and the ability of the rehabilitated landscape to resist degradation and retain desired functions (eg biodiversity protection or grazing productivity). However, success must be based on documented evidence that can demonstrate adequate progress towards rehabilitation targets and is assessed at appropriate intervals. To assist this task, a stepwise decision guide for the GCAA monitoring program was developed to ensure consistent monitoring data is collected across the range of sites. This presentation will discuss some of the processes that were followed to allow GCAA to identify appropriate metrics to assess rehabilitation success efficiently over thousands of hectares.CITATION:Erskine, P, Fletcher, A and Swart, P, 2016. Preparing for progressive mine rehabilitation sign-off in Queensland, in Proceedings Life-of-Mine 2016 Conference, pp 148–150 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By S Gulati, N Sarkar, T Vink, S Battersby, L Okada

This paper examines a successful project implemented by BHP Mitsubishi Alliance (BMA) and the Polymathian team at Deswik, aimed at enhancing short-term scheduling processes to reduce vessel turn times in the BMA Central Queensland coal value chain. The project’s objective was to digitalise the planning process to enable planners to make data-driven insights to improve the profitability of the value chain. The strategy involved developing a digital mining system that incorporates data storage, cloud computing, and the ability to meet the integration needs of both internal and external business systems. This was complemented by a sophisticated, optimisation-based, decision-support tool to enhance the planning teams’ ability to make timely and effective decisions.

Sep 1, 2024

By D van der Spuy, T Kewe, K Keet, N Moffatt, A P. Paine

The Blue Cube Mineral Quantifier Inline (MQi) instrument uses reflective light spectroscopy and advanced chemometrics to measure mineral or elemental grade in a slurry line. The instrument takes scans continuously and sends data to the DCS or PLC control system.Controlling the concentrate grades on a flotation circuit using low-frequency measurements can be difficult or impossible, especially on a circuit that has fast process dynamics. The ability to rapidly measure changes in grade makes it possible to continuously manipulate the flotation circuit operating parameters such as level, airflow and reagent addition set points to optimise plant performance throughout changing conditions.At Barrick’s Porgera mine in Papua New Guinea the flotation circuit feeds sulfide concentrate slurry to a pressure oxidation circuit. In order to maximise gold recovery in the flotation plant and increase performance in the pressure oxidation process, there is a stringent requirement to maintain a stable and optimum sulfur grade. The gold recovery is directly affected by the sulfur grade as most of the gold at Porgera is submicroscopic and associated with the sulfides (disseminated?pyrite).Porgera considered various points in the flotation circuit for installing Blue Cube analysers. This was part of a plant upgrade to improve process control. Due to budget constraints it was decided to initially only install one Blue Cube analyser on the final concentrate stream of the flotation circuit measuring sulfur, sulfides, gold and particle size. The accuracy of the calibration results were very good for all these properties. The sulfur measurement was used in an advanced control system to optimise and stabilise the grade. The paper presents comparisons between mineral grades determined using analytical laboratory analyses and the online Blue Cube data measurements, as well as benefits achieved by measuring grade online. An analysis of the plant data before and after installation of the Blue Cube and the advanced process control upgrade indicate that the flotation recovery increased by 1.98 per cent.CITATION:Kewe, T, Moffatt, N, Strobos, P, van der Spuy, D, Paine, A P and Keet, K, 2014. Evaluation of the Blue Cube MQi slurry analyser for application in an advanced control system for the optimisation of a gold sulfide flotation circuit, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 357–362 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014