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By V Lishchuk, C Lund

"Geometallurgy aims to improve resource efficiency by creating a spatial model of an orebody in order to forecast ore processing behaviour. This enables calculation of the economic value of each ore block and the use of this information for production optimisation and hence an improved economic return. Modelling uses different approaches to link geological information with mineral processing: traditional approach uses chemical elements; proxy approach – small-scale geometallurgical tests; and mineralogical approach – minerals.A geometallurgical model is obtained during execution of a geometallurgical program encompassing the entire value chain of ore processing. Available methods for establishing a geometallurgical model are in many cases limited and not yet comprehensively validated. Some of the limitations include: sampling density, assaying methods and quality, forecast accuracy block model content, geostatistical solutions for non-additive components, blending and assessment of positive impact of geometallurgy on the project. Synthetic ore models combined with process simulations and production scheduling, based on strong case studies, present a viable way to address these shortcomings. Such synthetic ore models will have realistic elemental and mineral distribution, textural attributes and 3D variability for input into the design of an appropriate geometallurgical program.A synthetic orebody was created for an apatite-bearing iron deposit. Variability in modal mineralogy was described by geostatistical parameters combined by a set of linear and trigonometric functions. The generated synthetic deposit model was used to develop a mine production plan to generate a simulated process feed. The process feed had detailed information required for beneficiation process simulation: modal mineralogy, chemical composition of minerals, grain size and specific gravity. The synthetic system was used to measure benefits that a geometallurgical program developed for real cases could provide, compared to production where only head grade is optimised. These include a reliable sampling strategy and confidence in the feed-quality forecast for economic evaluation.CITATION:Lishchuk, V, Lund, C and Lamberg, P, 2016. Development of a Synthetic Ore Deposit Model for Geometallurgy, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 275–286 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By P Myers, T Elkington, S Wonday

Sierra Rutile LimitedÆs (SRL) heavy mineral sand mining operation in Sierra Leone, West Africa, is embarking on a new phase of its life. After confronting many challenges during the 1990s and 2000s, SRL is embarking on a strategy of growth to recover maximum value from the mine over the rest of its life. Sophisticated linear programming techniques have been used to develop an optimum strategy for extracting SRLÆs many known deposits of economic grade, while considering options for expansion and for a variety of mining and processing methods and combinations. CITATION:Myers, P, Elkington, T and Wonday, S, 2012. Strategic optimisation at Sierra Rutile - A case study in maximising project value, in Proceedings Project Evaluation 2012 , pp 59-66 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 24, 2012

The JORC Code contains a mandatory classification system for Mineral Resource and Ore Reserve estimates for public reporting. The classification is a statement of the Competent PersonÆs confidence in the estimate and an attempt to convey that confidence to the various users of the resource estimate. In general the classification process is either largely subjective, relying on the Competent PersonÆs experience, or relies on statistical measures derived from the estimation process, or is derived from an estimated level of confidence in the outcome. However, the statistical measures may not necessarily relate to the overall confidence in the resource or reserve which must take account of the confidence in the geological inputs to the estimation.In addition to the traditional deterministic interpretation and estimations adopted by geologists, semi-quantitative techniques are now available to improve the estimation of confidence while continuing to involve the Competent PersonÆs experience in the process. Methods for quantifying confidence in mineral resource estimates for advanced projects and operating mines have also been developed.Classification is undertaken primarily as a communication tool between the estimators and the other stakeholders in the process. A brief examination of the stakeholdersÆ requirements is included.

Sep 26, 2011

Sampling errors result from heterogeneities within the lot under study. Within a rock mass in situ heterogeneity results in the geological nugget effect, which accounts for most of the natural variability. In broken rock, constitution and distribution heterogeneities are important. A major result of the constitution heterogeneity is the Fundamental Sampling Error (FSE) which is the smallest residual error that can be achieved. It cannot be eliminated, but can be minimised and refl ects the fact that the broken rock sampling process is never completely free of error. Together with other sampling errors, FSE contributes to the total nugget effect. The FSE for a sampling protocol can be evaluated using the so-called Gy equation. Its practical applications to low-grade gold ores have often been unsuccessful due to problems linking the FSE and minimum sampling mass and the defi nition of key parameters such as the liberation diameter. Well-designed sample protocols minimise the total sampling error and hence the nugget effect. Reduction of the nugget effect is a key requirement for all sampling programs whether related to exploration and resource evaluation, metallurgical test sampling, grade control or metallurgical plant sampling. This contribution reviews the relationship between heterogeneity, FSE and nugget effect in gold deposits; and emphasises the need for FSE management throughout the mine value chain.

Aug 1, 2010

By Q Wang

Net present value (NPV) has been the main criterion in mining project evaluation and production plan optimisation. It is a common practice in NPV calculations to take into account only the tangible cost items in the corporate accounting system. The costs incurred due to damage to the local ecosystem and environment are left out and treated as externalities. Such practice on the one hand underestimates the total cost of a mining operation and, on the other hand, ignores the difference in ecological/environmental impacts between different mine plan alternatives. This paper attempts to measure the ecological costs of mining and to incorporate such costs into the evaluation scheme in mining project evaluation and mine planning. The ecological costs of mining are estimated based on the areas and types of land (eg forest land, grazing land, crop land) damaged by mining activities and the carbon emission from fossil fuel consumption. For the land areas (and their associated ecosystems) directly damaged by mining activities, the ecological costs are measured by the prevention and restoration costs, the lost values of eco-services of the damaged land, including bio-product production, soil erosion control, water run-off control, oxygen release, air pollutant absorption and formation of soil nutrients. The ecological cost of carbon emission from the energy consumption of a mining operation is measured by the cost of cultivating the equivalent forest land required to uptake the emitted carbon. A case study on a large-scale open pit mining project is presented to demonstrate the influence of ecological costs on the mine planning outcome.

Sep 26, 2011

By J Jackson, E Sellers

Blasting related indices were developed to quantify variation in rock strength and structure for each stope, and for each lift of each stope, as part of a Mine to Mill study at an underground open stope mine. The indices were derived from combinations of data from underground diamond drilling because the simplifying assumptions contained in the block model prevented sufficient differentiation in rock mass characteristics to enable adjustments to the blast design.Application of combinations of blasting related indices enabled the identification of stopes with a high potential for inconsistent and oversize fragmentation, underbreak and overbreak. The indices also fragmentation outcomes to deliver increased material flow within stopes, better digability and predict indicative mill throughput. The stopes with issuesCalibration of the results enabled adjustments to the blast design based on the rock mass conditions and accordingly improved the blast outcomes. This enabled improved productivity by reducing underbreak and overbreak, having a more appropriate fragmentation, which reduces unplanned rock handling and improves bogging. The reduction in recovery drilling creates huge opportunities to improve output by reducing production delays and decreasing the overall cost per tonne. By understanding the explosive performance and blast energy distribution in relation to rock mass blastability poor, performing designs in blind upholes and convex stopes were identified.The conclusion of the work is that value improvement, regarding increased revenue and reduced costs, can be achieved across the whole underground Mine to Mill process chain by developing stope based indices from the existing geological information to correctly tailor the blast design to the rock within, and surrounding, the stope.CITATION:Jackson, J and Sellers, E, 2017. Blasting related indices as the key to underground blasting improvements in a challenging rock mass, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 23–32 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017

By Schaap W

A test on Taylor's rule of mine life using published data on open pit porphyry copper mines confirmed that mine life is, on average proportional to the fourth root of reserve tonnage. Deviations from this rule-of-thumb occur to a large extent as variations between regions that are qualitatively explained in terms of differences in grade, infrastructural needs or special taxation effects.

Jan 1, 1984

By S R. Williams

There is a sense of geometallurgy being new; a new methodology for mining project development and improved operational strategy. One of the main challenges that any ænewÆ technology faces is a validation of the value and the need to produce case studies. However, producing case studies can often be problematic particularly given the long cycle from mineral deposit project, through feasibility and construction to stabilised operation of a mine.However, the roots of geometallurgy go back quite some time. Successful practices with geometallurgy can be seen from as early as the 1980s. Many times those practices were not called geometallurgy but something else and, in other cases, what can be seen are various components of the geometallurgical ævalue chainÆ.This paper will analyse a selection of published past practices from a geometallurgical perspective to demonstrate the value realised from the application of this methodology. The paper will then make some general comments on where this history of work in geometallurgy has lead us to and what are the challenges today for the geometallurgical effort.CITATION:S R Williams, 2013. A historical perspective of the application and success of geometallurgical methodologies, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 37-48 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

By A Garvie, D Kentwell, J Chapman

"Most new mining projects require an initial assessment of the locations and volumes of potential acid forming (PAF) waste that is likely to be moved and dumped in surface waste stockpiles. This requires sampling of the waste rock zones and submitting the samples for a series of tests. Key to the outcome of the waste characterisation process is obtaining sufficient samples that are representative of the various rock types both in number and spatial distribution.Various regulatory bodies throughout Australia and the rest of the world are currently struggling with how to define minimum amounts of sampling to achieve realistic estimates without imposing excessive costs and time constraints on a project.This paper addresses two aspects of the process: what constitutes a æsufficientÆ number of samples how to use those samples in determining volumes of likely PAF material.Geostatistical methods of characterising orebodies with large numbers of samples are routinely used in the mining industry by geologists and geostatisticians to estimate and classify Mineral Resources. In theory exactly the same methods can be used to estimate PAF waste locations and volumes.In practice the number and spatial distribution of dedicated PAF waste samples at feasibility stage is typically so small that it is almost impossible to estimate the spatial distribution of PAF material with any degree of confidence at all. Consequently, the common approach is to characterise a few samples from a lithological unit and then assume that they represent the unit as a whole. This approach, however, can be fraught with risk.This paper describes some of the findings of SRKÆs evaluation of several coal projects with respect to PAF waste evaluation and highlights some common misconceptions held by people working in this area that do not have a knowledge of statistics or geostatistics.CITATION:Kentwell, D, Garvie, A and Chapman, J, 2012. Adequacy of sampling and volume estimation for premining potential acid forming waste evaluation using statistical and geostatistical methods, in Proceedings Life-of-Mine 2012, pp 79-88 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 10, 2012

The Mammoth Mine is located some five kilometres from the town of Gunpowder which is approximately 120 km north-west of Mount Isa in Queensland.

Jan 1, 1993

By J Folwell, G Phillips, F Gassner

Geomembranes selected for various applications often start with considering target properties developed by industry organisations such as Geosynthetic Research Institute (GRI), and test methods developed by ASTM and other Standards organisations The geomembrane types are typically, initially selected based on manufacturers recommendations and chemical resistance data from the manufacturer or industry knowledge. Geomembranes considered for this project included materials with material properties that exceeded the minimum target values of various test methods. The difficulty is in selecting which parameters are most important for a particular application and also what service life can be expected for the geomembrane under various chemical and environmental exposure conditions. Accelerated aging testing of candidate geomembranes in simulated exposure conditions can be useful to select the preferred geomembrane and predict the service life of the geomembrane under different exposure conditions. The exposure conditions of immersion in acidic tailings liquor, splash zone and freeboard zone were considered for evaporation ponds on a site with significant heat and UV radiation. Candidate geomembranes considered a range of different types of polyethylene liners. The results of the accelerated aging testing have allowed the selection of the geomembrane for the range of exposure conditions and evaluation of the expected service life of the geomembrane.

Jul 1, 2021

By H Bateman, I Cawrse, G Carnes, S Cawrse

In developing mineral resources, the focus typically centres on the management of identified social and environmental impacts and compliance with regulatory requirements. However, opportunities to protect and enhance the environment and communities are most effective in the planning and design phases. Achieving the objective of integrating sustainability considerations as an element of design decision making requires that the design criteria be technically sound, relevant to the project and applicable to desired design outcomes. This is particularly important for projects employing virtual teaming, where design engineers may be geographically dispersed and are unlikely to be familiar with site specific sustainability challenges and opportunities. This paper documents the approach taken by BHP Billiton to incorporate sustainability principles, objectives and guidelines in design criteria for the Olympic Dam Expansion (ODX) project. It describes the range of inputs used in defining sustainability objectives which interface in a framework that is dynamic and transferable to other mining projects and to engineering design in general. The Sustainability in Design Criteria document distils statutory requirements, corporate standards, lessons learned and leading industry practice into a single coherent framework that supports engineers to approach problem solving as a holistic and integrated exercise with a long term perspective. The framework also serves to improve linkages between internal stakeholders by fostering greater communication, collaboration and innovation to deliver more sustainable outcomes through the design process.

Jan 1, 2009

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

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

Sep 1, 2014

By Whiteman P. C, Stacey G. S, Hunter G. D

Processing of lead-zinc and copper ores by Mount Isa Mines Limited produces large quantit- ies of concentrator tailings waste which is pumped as a slurry to special dams where the solids are allowed to settle and dry out. These areas are unattractive and show no signs of encroachment by plant life even though the surfaces of some dams have remained undisturbed for more than a decade. During 1970 Mount Isa Mines Limited commenced a long term research program in conjunction with the Department of Agriculture, University of Queensland to deter- mine possible methods of establishing a plant cover on this material. Research has defined the major factors limiting plant growth in the tailings medium. Modification of the edaphic conditions through fertilizer inputs, particularly of phosphorus and nitrogen, and alteration of "soil" physical properties by incorporation of mulching mater- ials, provided conditions which allowed plant growth. The outstanding "soil" amendment treatment was incorporation of fly ash, a waste product of the company's coal fired power stations. A range of crop and pasture species have been selected which have grown well with adequate irrigation under the amended conditions in the field. Further research is assessing a range of native plant species and agronomic techniques to provide a stable plant cover on the tailings dams.

Jan 1, 1974

By H Turrer, M Badawi, R Belissont, Y Foucaud, E Kleiderer, L Southavy, J Mesquita, Y Basselin

The Mont Reed iron ore deposit, owned by ArcelorMittal, is situated approximately 140 km southwest of the Mont-Wright mine in the southern region of the Labrador Trough, Canada. Acquired by Québec Cartier Mining (QCM) in the 1960s, the Mont Reed mining property has remained unexploited due to the complex nature of the ore in the area. However, during the last years ArcelorMittal’s R&D team has been dedicated to developing a process to beneficiate the Mont Reed ore and produce high-quality pellet feed suitable for direct reduction furnaces. Extensive research revealed that achieving a good liberation degree of particles required grinding the material below 75 μm (P80 of 53 μm). To find the most effective technology for this task, a detailed comparison between ball mill and vertical stirred mill grinding was conducted. Both grinding technologies underwent detailed testing in bench-scale experiments. The ground products were comprehensively characterised, including size distribution analysis and chemical analysis per size fraction. Additionally, liberation analysis was performed using an automated scanning electron microscope (SEM). To determine the grinding specific energy, a method previously developed at Samarco (Brazil) for fine grinding of iron ores was employed. Furthermore, magnetic separation and flotation tests were conducted on the ground products. After a thorough evaluation of all the results, it was observed that both ball mill and vertical stirred mill grinding produced samples with similar physical characteristics. However, the vertical mill demonstrated higher efficiency in grinding the material. To conclude the study, an economic evaluation was conducted for both options considering various factors. Overall, ArcelorMittal’s R&D team’s dedicated efforts have brought them closer to unlocking the potential of the Mont Reed ore deposit and paving the way for its future utilisation to the production of high-quality pellet feed.

Sep 18, 2023

By R Stead

So many ceramics look the same, but are they?In the past 20 years, there have been significant changes in the materials available, as well as changes to the supply chain, for ceramics used in wear applications in the hard rock mining industry. The biggest change in supply has been from the Chinese market, with many suppliers promoting their products as æstate of the artÆ. Some of them are state of the art, but are they all? There will be some concluding remarks in this respect.There are still some outstanding new developments coming from the more traditional suppliers and these should not be ignored. However, as an end user, how can one be sure that the product received meets the technical specifications of that material?This paper will address some of the questions on how to differentiate between different materials by giving a technical overview of the current (but not exclusive) range of popular ceramics, plus incorporating how these ceramics are used in process plant products by presenting case studies. The presentation will include technical data coupled with micrographs of various ceramics to illustrate just why they are different.It will also be shown that by careful selection of the wear material, it is possible to gain significant benefit when using superior materials in an ore processing plant. The impact of cost of the products, life, process efficiency, and reduced maintenance costs will be considered using cyclone components as an example.The properties (including the microstructures) of the various ceramics will be compared to the application in order to get some understanding of what is considered good or bad.Misra and Finnie (1982) summarised their paper, æA review of Abrasive Wear of MetalsÆ by saying:à it is difficult to give guidelines for selecting materials for abrasive wear resistance. Each application is a different one, and a design engineer has to take into account various other factors such as impact, fatigue and corrosion which are often coupled with abrasive wear. The same applies to ceramics.CITATION:Stead, R, 2013. Applications of ceramic wear materials in the gold industry, in Proceedings World Gold 2013, pp 325-330 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By M Rafty, A Markham, S Atkinson

Australia contains some of the most productive mining areas and is characterised by ancient landscapes and highly variable hydrology. Historical mining of iron ore, coal and other minerals has targeted ore deposits located above water tables, and elevated above creek lines where possible to reduce cost. The downturn in mining caused by falling ore prices over recent years has triggered a drive to reduce cost, maximise yield and delay capital expenditure associated with opening new mines. So as the ore deposits with more favorable mining conditions become depleted there is an increased focus on mining ore associated with valley floors and creek lines. This is demonstrated by a regional assessment of the extent of Channel Iron Deposits (CID) and Iron Ore (Fe) Mines and Deposits in the Pilbara Region of Western Australia (Figure 1). A large proportion of these mines are, or plan to, target high grade CID ore associated with existing creek systems. Figure 2 shows outcropping and inferred sub-cropping CID extents, which suggests there are vast quantities of CID ore deposits throughout the Pilbara Region, intersected by major creeks which could be mined at some point in the future using creek diversions (Atkinson et al., 2017). A similar picture could also be produced for coal mining in Queensland, particularly in areas such as the Bowen Basin.While creek diversions provide an opportunity to maximise the utilisation of these orebodies and extend the life of mine, creek diversions can involve substantial financial, social, environmental and regulatory risks that need to be carefully managed (Markham et al., 2017, Atkinson et al., 2017). This paper discusses the key issues and opportunities associated with diversion decision making. It highlights the importance of using a well-structured assessment methodology that allows key stakeholders to be part of the assessment process and is complementary to material presented in Atkinson et al., (2017). Design considerations for operational and closure designs are presented, as well as mine planning considerations, risks, cost saving opportunities and the benefits of an integrated approach to design. The role technology plays in diversion design and performance monitoring is discussed as are the potential opportunities for the future.CITATION:Atkinson, S, Markham, A and Rafty, M, 2018. Diversion decision making with an integrated approach to design for operations and mine closure, in Proceedings Life-of-Mine 2018, pp 74–79 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By P V. A van der Westhuyzen

Namakwa Sands is a heavy minerals mining and beneficiation business in the Exxaro Sands Division, and operates along the West Coast of South Africa (see Figure 1). The business encompasses mining, mineral concentration, separation, and smelting operations. Inflated commodity prices and increasing operating costs demands greater attention to the management of process performance and the company wide coordination of resources. Consequently, the task of deploying operational/technical skills and budgets into the most appropriate parts of the business assumes great importance in order to increase productivity from its capital assets. The mineral sands industry is under the same sort of economic scrutiny that all other industries find themselves, and as such, Exxaro – Namakwa Sands has taken the strategic initiative to improve overall resource utilisation within the processing steps and to measure the costs associated with obtaining this value.This paper provides details of the successful implementation of a Kelsey Centrifugal Jig (KCJ) at Namakwa Sands to recover primary and secondary zircon products from the wet gravity (quartz) rejects generated and stockpiled at the Mineral Separation plant (MSP).

Oct 5, 2011

By M Erskine, R Mills

This paper approaches tailings dam risk management from the perspective of how other high hazard industries approach the management of their catastrophic event risks, with the aim to provide recommendations from these learnings for the industry to adopt.

Jul 1, 2021

By D L. Reid, G Nwaila, J Petersen, J-P Franzidis, Y Ghorbani, M Becker, F C. de Beer, L C. Bam

Traditional methods of gold extraction have involved comminution and processing via cyanide leaching, all of which are associated with energy, cost and environmental implications. Subsequently, numerous opportunities for improvement and optimisation strategies in gold mining and processing have been explored, including heap leaching, which has significantly lowered comminution costs. This paper explores the effect of the more energy efficient high-pressure grinding rolls (HPGR) on the comminution behaviour (especially on the crack density) and cyanide leaching performance of laboratory reactors study on run-of-mine gold ore comprising the Ventersdorp Contact Reef (VCR) and the Elsburg Reefs (ER), sourced from Carletonville in the Witwatersrand Basin in South Africa. The ore was comminuted using HPGR at three different pressure settings (120, 90 and 60 bar). Large (-16/+11.2 mm) and small (-5.6/+4 mm) particles of the HPGR product where then mineralogically characterised using optical microscopy, quantitative evaluation of minerals by scanning electron microscopy (QEMSCAN) and X-ray computer tomography (CT) before cyanidation. The results of the leach experiments indicated a correlation between gold extraction, particle size and crack density. Mineralogical characterisation of the ore indicates that the Fe-sulfides present in the VCR are likely to be more reactive than those in the ER, thus having a more favourable influence on gold cyanidation. Overall, the results show promise for the heap leaching of Witwatersrand gold ores prepared using HPGR and demonstrate the value of a multi-disciplinary geometallurgical approach.CITATION:Nwaila, G, Becker, M, Ghorbani, Y, Petersen, J, Reid, D L, Bam, L C, de Beer, F C and Franzidis, J-P, 2013. Morro do Ouro geological model with a metallurgical view, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 75-84 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013