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By L J. de Lange

As a material asset for mining entities, the resources and reserves (RR) estimation processes are surprisingly underrepresented in the assurance landscape. When press reports expose them being inaccurately reported, or in merger and acquisitions processes, their importance becomes clear. The impact of erroneous RR numbers (both positive and negative) could have a material impact on an entity’s reputation and value.The technical nature and ‘black magic’ connotations of the RR estimation processes are possibly reasons why audit committees are not actively involved with it. Internal auditors avoid the RR processes for similar reasons. Also the traditional approach to obtain assurance on RR is expensive and is therefore only performed when it is absolutely required.However, stakeholders’ expectations of good governance are growing. Part of this increased focus is based on attaining a higher degree of certainty about the current and forecasted position of the entity. Stakeholders are also increasingly more interested in non-financial areas of entities, as the future success of an entity is more than a set of financial metrics.Consequently, the RR estimation processes should be visible on the agendas of audit committees. Monitoring of key controls is required as part of the governance obligations for senior management and the audit committee. So once it is on the audit committee’s agenda, the question then becomes, how will that agenda be supported by an assurance process that is cost-effective?The main objective of the paper is to describe a model of RR assurance that has been effectively applied in some mining companies. The paper discusses one particular approach that provides an audit committee with the required assurance regarding RR processes. The approach ties the assurance needs of the audit committee to the needs of the technical experts in the entity, therefore involving two important figures. It also offers assurance providers with a model to audit ‘through’ the RR processes rather than ‘around’ them. The paper then discusses top-down and bottom-up approaches that provide assurance at different levels of an entity.A governance audit that focuses on the RR processes is suggested as a top-down approach. A bottom-up approach assesses the design adequacy of internal control processes. A hybrid model is described which meets the needs of diverse stakeholders including the audit committee and the RR community.The hybrid model combines the expertise of professionals in both internal audit and RR. The right balance of these skills directed by a singular approach ensures that a credible result is achieved.This approach is not as expensive as some verification approaches used in the industry and can, as a result, be performed on a more regular basis.The last element of the paper looks at implementation of the reporting mechanism. An assurance process aimed at continuous improvement further enhances the robustness and reliability of RR reported by an entity.CITATION:de Lange, L J, 2016. Resources and reserve assurance processes – a framework for improved governance, in Proceedings International Mine Management Conference, pp 21-34 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 22, 2016

In the last 40 years, New Zealand has developed a number of liquid- dominated geothermal steam fields, for electricity generation and indus- trial process steam. New technologies were developed, and in this work, New Zealand led the world. The policy of full publication of the results, in a wide range of sciences, provided a reservoir of detailed data defin- ing the geology, size and shape, and the chemical and physical regime, of many geothermal fields and their constituent parts. The discovery of precious and base metal deposits /precipitates in geothermal drill cores and steamfield equipment, suggested a clear link- age with epithermal mineral fields in general, and with that of the Coromandel (Hauraki) Region in particular. Further work on geothermal/ epithermal relationships have implied that the techniques, developed to obtain an understanding of geothermal fields, could be applied also to epithermal mineral exploration. This work is developing fast, and is now proceeding in many coun- tries. Future work may show that the presumed relationship between geothermal and epithermal deposits may be applicable in the wider con- texts of all hydrothermal deposits, and possibly in many other minera- lised areas with volcanic "country rocks".

Jan 1, 1988

By A Atkins

Six recent case studies were selected based on the eight main causes of mine disasters (Table 1; Quinlan, 2014) and where credible information sources, such as Royal Commission Reports, Coronial Investigations and textbooks, were available. The six case studies are listed below. Details are available via this link or the conference PowerPoint accompanying this paper. 1. Beaconsfield, Tasmania – 2006 Fall of Ground/Seismic Event (Chandler, 2009; Melick, 2007; Wright, 2012). 2. Bingham Canyon, USA – 2013 Manefay Slide (Ross, 2017). 3. Bronzewing, WA – 2000 Hydraulic Fill Inrush (Hope, 2002). 4. Brumadinho and Samarco, Brazil – 2015 and 2019 Tailings Storage Facility (TSF) failures (Bowker, 2019; Darlington et al, 2019; Demajorovic, Lopes and Santiago, 2019; Morgenstern, 2016). 5. Northparkes, NSW – 1999 Cave Air-blast (Bailey, 2003; Hebblewhite, 2003). 6. Pike River, NZ – 2010 Methane Gas Explosion (Macfie, 2013; Panckhurst, Bell and Henry, 2012.

May 5, 2022

By G Burton, S Fityus, J Li, S Vaughan, D Payne

Daunia and Caval Ridge coal mines, owned and operated by BHP, have been co-disposing rejects and dewatered tailings within spoil dumps from the beginning of their operations in 2013 and 2014, with the purpose of minimising environmental impact and geotechnical risk. Following the recent large failures of tailings dams around the world, BHP Coal, through its Coal Tailings Program, plans to transition other coal mines to deliver “dry” tailings and produce mixed plant rejects (MPR) for inpit co-disposal. This will materially reduce future tailings dam risk exposure. Previous laboratory shear strength testing was conducted on rejects with a maximum particles size of 20 mm, and some concerns were raised that this might not represent the mechanical properties of the actual full particle size distribution (PSD) rejects. BHP was also aware that using different technologies to dewater the tailings, such as belt press filters (BPF) and solid bowl centrifuge (SBC), could produce thickened tailings which could significantly modify the physical behaviours of the MPRs, particularly the bonding between particles. Therefore, laboratory testing on both coarse rejects and mixtures of the coarse rejects and dewatered tailings (MPRs), with full PSDs, was carried out. Testing was performed using the large direct shear machine developed by the Australian Coal Association Research Program (ACARP) project C20019 in 2017, as well as a 300 mm diameter triaxial apparatus at the University of Newcastle (UoN). This paper presents details of the laboratory testing program and results for the rejects from the first studied mine of the BHP Coal Tailings Program. It compares the shear strengths measured at full scale with those tested on modified (scalped or crushed) specimens in the past; and discusses the tailings dewatering technique selection from geotechnical aspects based on the testing results, and finally presents some dump and tip head stability analysis results using the testing results.

Jul 1, 2021

By P G. Doig

Recent drops in commodity prices and economic uncertainty have seen many businesses re-evaluate their operational expenditure to ensure mine profitability. The high capital and operational cost of truck and digger fleets has resulted in loading and hauling of material being a significant proportion of a mine’s expenses (Nel, Kizil and Knights, 2011), thus it is often one of the first areas to be considered for cost reduction. If an operation requires additional trucks to maintain or improve productivity, a robust justification is crucial due to the expenditure involved.Mining schedules form the basis of productivity and cost estimations for mining operations and therefore must have a significant level of confidence with regards to achievable quantities and rates. Traditionally, a mining schedule is produced without detailed consideration of the trucking capacity or requirements. Although some mine planning software incorporates haulage predictions into schedules, most cannot model the dynamic nature of dumping and haulage. Previous studies have shown that it is necessary to have detailed haulage analysis instead of the traditional mining block centroid to dump block centroid methods for more realistic mining schedules and cost estimation (Doig and Kizil, 2013).Recent developments in software have allowed the dynamic integration of haulage analysis with mining schedules. Engineers can now create mining schedules in conjunction with dumping schedules, allowing mining schedules to reflect the restrictions created by the number of available trucks, combined with dynamic consideration of available in-pit and out-of-pit dumping locations.A study has been completed producing a mining schedule in conjunction with a dumping schedule and haulage analysis. Multiple schedules were run with various haulage strategies (including minimising rehabilitation liability) and truck availability to identify the impacts on coal production, and hence revenue. A financial analysis was then completed where a net present value (NPV) was calculated for each scenario. The study showed that trucking shortfalls can significantly impact mining schedules and cost estimations, both in terms of cost as well as revenue lost when trucks cannot maintain forecast production rates, thus dumping schedules and haulage analysis should be completed simultaneously. If dumping and haulage is not considered when planning the mining schedule, a mining business is ignorant to the impacts trucking has on the mine production, closure risk and profitability.CITATION:Doig, P G, 2014. Value impacts of truck limited scheduling, in Proceedings Life-of-Mine 2014 , pp 513–524 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

Organisations are starting to develop processes for achieving sustainability principles they have defined for their organisation. The foundation for these principles is now well accepted. The definition of a sustainability framework is a good starting point for any project. The delivery of the framework requires the organisation to think differently about how project objectives can be met. New tools are becoming available to help achieve the sustainability outcomes for the projects. This paper will examine the project building blocks that are necessary to ensure the sustainability framework can be achieved for the project. These include new approaches to decision-making processes and evaluation tools and when to apply them. An integrated approach with shared expertise to project delivery, which is applicable to the whole supply chain, will be discussed. This will cover sustainability procurement, integrated waste management, cleaner production and eco-efficiency, sustainable products and disposal. A project toolkit will be presented and some key project tools identified. The need for management support in undertaking these new approaches is critical, as is the need to develop partnerships and cooperative management to facilitate delivery.

Jan 1, 2004

By S C. Barrie

St BarbaraÆs Marvel Loch operations have successfully used longhole open stoping as the primary mining method for a number of years. A transition to Core and Shell mining was implemented in 2009 to recover substantial ore grade resources remaining in sill and rib pillars. The transition to core and shell for the Exhibition lode required continuous waste filling of created voids and thus the removal of the crown pillar at the base of the Exhibition pit by blasting. Access to the top of pillar was denied as the pit was partially rock filled with waste rock from underground development.Beyond the technical challenges of the blasting project, a simple and transparent risk management process was developed to ensure appropriate controls and mitigating strategies were in place to minimise risk to personnel during the pillar removal process.Although failure of the crown pillar was anticipated but with the actual timing unknown, on 25 December 2011 the crown pillar yielded during normal mine operations. Engineered and isolation controls in place at the time were of a sufficiently high standard to ensure limited exposure of the underground workforce and minimal damage to mine infrastructure. Successful risk management through implementation of appropriate controls during the project lifecycle of two years and three months proved to be fundamental to the safe removal of the crown pillar.CITATION:Barrie, S C, 2012. Successful risk management through project life cycle for removal of the crown pillar at the Marvel Loch Underground Mine, in Proceedings International Mine Management 2012, pp 125-134 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 20, 2012

The sinking of the new No. 3 Shaft being mainly concerned with providing for the continuation of mining operations north of the existing workings, requirements for the shaft and haulage equipment were assessed, having in mind the anticipated needs of the Company in future years, the .available knowledge and probable future trends of the orebody, and also that the shaft would be required to act as a downcast airway for the ventilation system associated with the northern underground workings.

Jan 1, 1957

By H Barrie, L Ameglio

"Current methods for acid rock drainage (ARD) mitigation revolve around insulation of the waste from oxygen in the atmosphere with water and dry (soils and liners) covers. Both are of limited effectiveness and present significant drawbacks. Furthermore, while they reduce oxygen influx, they reduce but do not prevent ARD.The inert gas mixture (IGM) technology has been designed to overcome the deficiencies of gas transfer into tailings and waste rock materials across the surface and instead block oxidation by controlling the transfer of oxygen from the atmosphere. Inert gas is injected into the mine waste at low flow rates and the positive but low flow purges the oxygen that tends to diffuse into the sulfide waste across the surface. The positive flow of IGM compensates for inward oxygen diffusion and creates a pressure drop across the cover layer preventing inward diffusion of oxygen and, hence, acid generation.The IGM processes are evaluated in this paper: theoretically, with a review of the theory of ARD and the current state of knowledge about the performance of notably dry covers as atmospheric oxygen barriers via models to predict the performance of the IGM technique practically, with a bench-scaled experiment.The results demonstrate the effectiveness of IGM to prevent oxidation of sulfide minerals and ARD in waste rock. The laboratory experiments further identified key variables to be used to monitor performance and control efficiency of IGM, which is now awaiting field-scale application.The IGM technology is a patented process by Terraquest Technologies Ltd (Canada) in USA, Canada and Australia. The IGM technology can be cost-effectively manufactured on-site with commercially available compressors and gas filtration membranes. It is predicted that low-cost covers can then be utilised with IGM, which in turn lowers the overall capital costs of ARD mitigation.CITATION:Ameglio, L and Barrie, H, 2015. Acid rock drainage prevention using inert gas mixture technology, in Proceedings Tailings and Mine Waste Management for the 21st Century, pp 85–96 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 27, 2015

By H Hoogvliet

The Goondicum Crater industrial minerals deposit is located about 30 km east of Monto, Central Queensland, Australia. Early exploration programs in the 1990s found alluvial ilmenite along the banks of the Burnett River. This mineralisation was traced upstream to the Goondicum Crater. The Goondicum Crater is a topographic feature centred on a roughly circular 6 km diameter layered gabbro complex. Significant ilmenite, apatite, titano-magnetite and feldspar mineralisation are present in a weathered horizon up to 25 m thick. After several drilling campaigns in the Crater and subsequent feasibility studies, the project was developed by Monto Minerals Ltd, an ASX listed company, in 2007. However, the project never achieved production performance expectations and ran out of commissioning funds. The company subsequently went into voluntary administration in August 2008.In 2009, the RMM Capital group, of Brisbane, took control of Monto Resources Pty Ltd, and renamed the company Belridge Enterprises Pty Ltd (Belridge). Belridge commissioned a redevelopment study aimed at recommencing mining and processing operations. As part of the redevelopment study the authors planned a drilling campaign, managed a quality control program and developed a block model. This paper describes the drilling program, analytical procedures, quality control procedures and the preparation of the block model.The block model for the resource estimate was created using 1 m high blocks, wireframes defining the main material types, and 2.5 m thick horizontal search ellipsoids with a radial pattern. The deposit was ‘flattened’ prior to modelling. To assist with the economic evaluation of the project, each block in the model was assigned a net dollar value based on economic parameters provided by Belridge, including anticipated revenues and costs. This modelling technique allowed for efficient investigation of various scenarios and was used extensively in the development and optimisation of the project’s financial model. At a zero net value per block, comparable to a break-even cut-off grade of four per cent ilmenite equivalent, the Indicated plus Measured resource is estimated at 51 Mt, averaging 4.1 per cent ilmenite, 1.9 per cent apatite and 2.5 per cent titano-magnetite.

Oct 5, 2011

By A Van den Bulck, K Verbeken, O Vergote, I Bellemans

Viscosity is one of the most important physicochemical properties during pyrometallurgical operations. In the sub-liquidus regime, an important factor is the presence of suspended solid particles, yet its influence is not well-described in earlier literature, despite the significance of this factor. This project aims to determine the influence of spinel particles (Zn(Al,Fe)2O4) on the rheology of a multiphase synthetic PbO-SiO2-ZnO-Fe2O3-CaO-Al2O3 slag system. Three data sets with a wellcontrolled methodology and three different spinel sizes (small (13 μm), medium (34 μm) and large particles (76 μm)) were published previously, using a custom-built high-temperature rheometer. This study presents an additional data set of slag viscosity measurements, performed using a different apparatus, the Anton Paar FRS 1800, to verify the consistency of the earlier determined viscosity behaviour. Within this data set, no consistent trend could be found between the predicted wt per cent spinel and the relative viscosity. Therefore, additional quenching experiments were conducted to identify the morphology and experimentally determined volume fraction of the spinel particles in the slag. These measurements revealed a difference in spinel size across the samples and corresponding viscosity behaviour, emphasizing the importance of spinel particle size on slag viscosity. Once the spinel size was taken into account, consistent viscosity results (relative apparent viscosity and flow index) were observed across the two devices. This study confirms that, once all parameters affecting slag viscosity are considered, the viscosity behaviour of a heterogeneous slag can be uniquely determined. The resulting optimised slag viscosity models can be used to predict viscosity before processing, addressing relevant phenomena such as slag tapping, slag foaming and copper droplet settlement.

Aug 21, 2024

By W Patton

Investment decisions in the mineral resources sector are made on the basis of an assessment of the economic potential for a mineral deposit. Given the supporting information for the location, scale, and quantity of the commodity of interest, miners and investors aim to make risk-informed decisions when considering further investment. The objective of resource classification is the synthesis of various types and quantities of geologic information used in resource model construction to assign confidence categories to the estimated mineral resources, which can then be used to support informed economic decisions. In this paper a risk-based classification scheme for iron ore mineral resources using conditional simulations is presented. The method involves categorisation of each block according to a confidence level, considering expected recoveries from a kriging model over mining production volumes. The realisations of the simulated model are used to assign risk-based confidence categories to zones of the ore deposit. One motivation for this work is to assess the sensitivity of the scheme to geologic uncertainties. Specifically, that which uncertainty in the layout of mineralising alterations and weathering overprints influence variabilities of associated rock properties and the likelihood of obtaining expected ore recoveries. It is shown these risks have material implications for a project’s economic potential. How the scheme can be extended to the grade control context and the value subsequent grade control activities is also quantified.

May 24, 2023

By G F. Johansen

The erratic and localised occurrence of economic gold grades is a common feature of high-nugget effect gold veins. The nugget effect is a consequence of small-scale geologically controlled enrichment, and the inclusion or exclusion of sparse gold particles because of the sampling process. Such deposits do not always contain visible or coarse gold, and can be characterised by fine gold particles. Economic grade accumulations are generally contained within discrete oreshoots, which are surrounded by barren to low-grade material. Problems are often encountered where small sample types (eg drill core or channel samples) often vastly understate in situ grade, due to their general inability to intersect rare gold particles. As a result, the definition of grade and its distribution is often challenging, and leads to substantial resource uncertainty. Proxies, or indicators for grade, can help the geologist gain a better understanding of grade distribution and grade potential. These are based upon geological (eg mineralogical, textural, etc) and/or geochemical (eg specific elemental ratios, fluid inclusion compositions, elemental correlations, etc) criteria. The paper discusses the use and application of such proxies through three case studies.

Jan 1, 2004

By Read T. A

THE Broken Hill South Ltd. is one of ten companies operating on the Broken Hill lode (See Fig. 1). It has two leases-Blocks 7 and 8-of a total length of 2250 ft. on strike of lode.From the surface to 425-ft. level the ore was found principally in the form of carbonates and high-grade friable sulphides. Below the 425-ft. level the ore is found in the form of compact sulphides. The ore-bodies found in the South mine may be broadly divided into two classes...

Jan 1, 1921

By P M. Ashley, M T. Costelloe

The Mary Kathleen tailings storage facility (TSF) contains 7.1 Mt of uranium mill tailings. This waste repository was rehabilitated in the mid-1980s using a multibarrier dry cover. At the time of mine closure, it was predicted that acid mine drainage (AMD) generation would not eventuate and that uranium, heavy metals and radionuclides would be adsorbed within the tailings and not seep from the TSF into the environment. This study reports on the environmental status of the TSF. Gamma-ray measurements indicate an intact dry cover of the waste repository. However, seepage (~0.5 L s-1) of acid (pH 5.71), saline (0.31 per cent), high conductivity (8.8 mS cm-1), slightly oxygenated (DO 2.6 mg L-1), radioactive waters occurs from the toe of the tailings dam into the former evaporation ponds and local drainage system. Seepage waters are calcium-magnesium-sulfate rich with elevated Fe, Mn, Ni, U and Zn values. Oxygenation of tailings seepages causes the precipitation of Fe and coprecipitation and adsorption of other metals (Pb, U, Y), metalloids (As), rare earth elements (Ce, La) and radionuclides (U-235, U-238, Th-227). In contrast, Ba, Ni, Sr, Mn, P, S, Ca, Mg, Na and K as well as Ra nuclides (Ra-226 and Ra-228) remain in solution until pH neutralisation and evaporation lead to their precipitation in efflorescences and sulfate-rich evaporative sediments further downstream. Dry capping of Mary Kathleen uranium mill tailings has resulted in physical containment of the wastes. The dry cover shows no signs of erosion and radiation levels are within acceptable limits. However, the flow rate of surface seepage from the TSF occurs at a much higher rate than predicted. Also, the neutralising potential and adsorption capacity of the tailings and underlying aquifer were overestimated at the time of mine closure. AMD has developed mobilising metals, metalloids, rare earth elements, alkalis, radionuclides and sulfate from the waste repository into surface water seepages.

Jan 1, 2003

By E C. Holloway

"The financial valuation of mining assets has a number of fundamental differences to the valuation of many other asset groupings. One such difference is that typically, the greater proportion of both the cost and revenue sides of the cash flow are inherently governed by systemic market forces.As a result, the range of outcomes for the valuation of each mining asset is more unpredictable, with higher levels of risk and uncertainty. In contrast, the management function of many other non-mining businesses or industry groups can control at least a portion of the cash flow by maintaining the margin or controlling the sales price. The management teams of mining businesses and operations typically have limited options, and are thus price-takers for both costs and revenues. As mining is an inherently cyclical industry, large, long-life operations can exist through several price cycles, making valuation both subjective and challenging.The outcomes of both static- and stochastic-based valuations, as well as the internal probabilities of the associated cash flow statements, are significantly impacted when the correlations between the appropriate parameters are quantified, modelled and incorporated into the valuation framework. The appropriate parameters for correlation modelling primarily include those that are governed by systemic market forces. Applying this process results in a different risk profile for the asset by allowing the risks resulting from systemic market movements to be more accurately quantified and then objectively minimised. This process also reduces the level of residual uncertainty in the valuation outcome.This paper presents a valuation methodology to pragmatically incorporate this level of valuation sophistication and statistically quantify the associated increase in the level of confidence of the valuation outcomes reported.CITATION:Holloway, E C, 2016. Correlated valuation methodology, in Proceedings Project Evaluation 2016, pp 181–200 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 8, 2016

By I Lumsdaine

QNI Pty Ltd operates the Yabulu Refinery located 25 kilometres north of Townsville, North Queensland. The plant treats nickel laterite ores sourced from the Philippines, Indonesia and New Caledonia. The cobalt head grade and overall recovery expectations for the 2001/2002 financial year are 0.161 per cent and 53.8 per cent respectively. Cobalt is a valuable byproduct derived from the nickel refining operation which utilises the Caron Process. Any increases in cobalt recovery that are achieved from the existing relatively low level provide significant improvements to the bottom line of the operation. Towards the end of 2000, a project was undertaken to characterise cobalt losses with the sole purpose of improving cobalt recoveries using a variety of analysis techniques. The Time-of- Flight Secondary Ion Mass Spectrometry (TOF-SIMS û University of South Australia) method was used to verify the presence of surface bearing cobalt species, originating from either co-precipitation or adsorption mechanisms. Cross-section examinations were also performed using Scanning Electron Micrscopy (SEM) and Energy Dispersive X-ray Spectrometry (EDXS). These techniques indicated the presence of high cobalt concentrations (in the order of several per cent) within a select number of roasted and leached ore particles. The phenomenon of cobalt losses due to incomplete leaching within specific ore particles was not widely documented within the Refinery prior to these studies. In order to quantify losses via this mechanism, Mineral Liberation Analysis (MLA û JKTech Centre) was also performed on key samples. This paper serves to document a systematic approach in determining the source of significant valuable mineral losses in an established, operating plant. It discusses the use of a variety of analytical techniques, which have been adapted for the minerals processing industry, but are strongly relevant for plant investigations in the hydrometallurgical industry.

Jan 1, 2002

By G M. Jones, J Rademan

Debswana, owned by the Government of the Republic of Botswana (GRB) and De Beers in a 50:50 joint venture partnership, operates the Jwaneng diamond mine in Botswana - the most valuable diamond mine in the world. The mine provides between 60 - 70 per cent of DebswanaÆs earnings, and about 30 - 40 per cent of the GRBÆs income. In 2008, the company embarked on the Cut 8 Project - an open pit waste cut-back to expose more diamond bearing ore to sustain mine life by another six to seven years. This undertaking was much larger than previous cut-backs; it increased the waste stripping ratio threefold, increasing significantly the waste handling fleet of trucks, shovels and infrastructure, and impacted a large part of the materials handling plant which required replacement with new facilities. The project coincided with the beginning of the Global Financial Crisis (GFC) and a slowdown in the economy. Its $4 billion total life cost was billed as æthe largest private investment project in BotswanaÆ which produced heightened expectations amongst stakeholders that it would redress some of the issues brought about by the GFC and leave behind a legacy of jobs, increased opportunities for citizen owned business and improved social infrastructure.Most of the big project challenges were non-technical and ranged from dealing with various stakeholders?at?all levels, a 25 per cent currency depreciation of the Botswana Pula against the South African Rand, obtaining work permits for non-citizens in a job starved environment, managing construction to world class safety standards, managing the low productivity of construction workers and producing a viable legacy program that satisfied the GRB and stakeholders. Whilst most of these risks were identified in front end studies, the magnitudes were in many instances underestimated. Managing this uncertainty on Cut 8 can provide valuable lessons to other projects in a similar environment, or at least provide the information to indicate that these factors should be adequately provided for in the financial evaluation of a project in the form of budget, schedule, contingency or risk mitigation.CITATION:Jones, G M and J Rademan, 2012. Reliability of expert judgements and uncertainty assessments, in Proceedings Project Evaluation 2012 , pp 109-116 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 24, 2012

MIM Holdings Limited has acquired a reputation for the successful application of R&D to develop break-through technologies for the mining industry. The Isa Process tank-house technology has been licensed to copper refineries throughout the world, and almost 40 per cent of the worldÆs copper is refined using this technology. Isasmelt copper and lead smelting technology is either in use, or is currently being installed, by eight companies in eight countries around the world. Jameson Cell technology is widely used in the coal mining industry and increasingly in the base-metal industry. The IsaMills developed at Mount Isa and McArthur River made it possible to develop the McArthur River and George Fisher orebodies. This paper will address the need for innovation and then discuss the development of the IsaMill and Isasmelt technologies. It will conclude with some comments about why MIM has been so successful in developing such technologies.

Jan 1, 2002

By I Grewal, M Lundt

Dense medium separation (DMS) is one of several preconcentration methods used for early waste rejection from run-of-mine ores at relatively coarse particle sizes prior to additional milling and beneficiation. DMS has been used extensively in the coal, diamonds, mineral sands, base metals and iron ore industries to produce either a final product or as a preconcentration step. Laboratory scale and pilot test work at the Met-Solve laboratory in Canada has demonstrated successful separation and upgrading of other minerals such as lead, zinc, copper and lithium based ores using DMS.This paper reviews historical dense media systems, results from the pilot-scale multi-stage DMS Separator “Condor” system, as well as production plants and associated laboratory heavy liquid separation (HLS) test work on various minerals. The mineral systems tested included a lithium bearing ore and a fluorspar ore. Other minerals were tested but are not reported in this paper.Pilot plant test work on a fluorspar ore showed that 41.6% of the mass could be rejected to the tailings stream while 95.3% of the CaF2 was recoverable to the product stream. On a spodumene sample that was tested, it was possible to reject 55% of the mass to tailings while recovering over 90% of the lithium.In recent market conditions and with the decreasing grades in existing ores, preconcentration should be a consideration to maximise the value of certain operations.CITATION:Lundt, M and Grewal, I, 2017. Dense media separation – a valuable process for preconcentration, in Proceedings MetPlant 2017, pp 122–130 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017