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The recent boom in the mining industry has lead to some unique challenges in successfully operating processing plants. With high turn-over rates of both operators and technical staff, and many experienced personnel leaving regional sites for city based jobs there is often an onsite knowledge vacuum and this in turn puts pressure on both site training departments and senior metallurgists to provide the relevant skills to the continuous stream of new staff. Frequently both operators and new metallurgists are instructed on a æhow-toÆ basis rather than giving them the understanding as to why tasks are performed and decisions are made. This paper has been written with the plant operator and metallurgist in mind and aims to provide suitable material to be incorporated into a site training manual. Topics have been broadly divided into the following categories: factors that operational staff can control; including pulp density, air addition rate, froth depth, particle size and reagent type and use; factors that operational staff cannot control; providing general information on bubble size, froth stability, pulp chemistry and the mechanical effects of the rotor/stator system; and process improvements. Each topic is discussed with a view to clarifying the key process variables that need to be understood and optimised in an industrial operating plant.

Jan 1, 2009

By King R. L

Low-enthalpy geothermal groundwater resources occur at relatively shallow depths in the Upper Cretaceous/1'ertiary sedimentary sequence in the on-shore Gippsland Basin. The main stratigraphic unit containing hot groundwater is the Latrobe Group. Groundwater temperatures in the range 30 to 70¦C have been recorded from depths between 500 and 1000 m. The hottest groundwater is in the Latrobe Valley and Lake Wellington depressions. Geothermal gradients in these areas range from less than 2¦C/100 m to over 10¦C/100 m (compared to a world average of about 3¦C/100 m). A number of theories have been advanced to explain the geothermal anomalies including exothermic reaction such as oxidation of coal, mixing with deeper, hotter groundwater and high geothermal fluxes along fault zones. Variations in geothermal gradients can also result from type and thickness (and hence thermal conductivities) of the sedimentary pile, depth to consolidated basement rocks, and influence of groundwater flow patterns including proximity to recharge zones. The hot groundwater in the Gippsland Basin has substantial potential as a source of energy for direct heat applications such as process heating, space and water heating for buildings, and agricultural and aquaculture. Geothermal energy has a number of environmental advantages over traditional sources of energy. It is clean, safe, causes minimal land disturbances and in most cases is naturally renewable.

Jan 1, 1992

The use of comparative sampling methods during the evaluation of the tin-copper deposits at Cleveland mine yielded closely checking average results from groove, channel, AXT split diamond drill core, and bulk sampling for both tin and copper content of the ore.The weighted mean tin and copper grades and values for the groove, channel, and split core samples showed small percentage differences from bulk sample results, and the F-ratio test for single population origin of the four types of samples was accepted at the 99· 5 per cent level of confidence.These results indicate that grade estimates based on the assays from AXT split diamond drill core and/or groove samples would be reliable within practical limits.

Jan 1, 1968

By A Hanna

Quarries around Auckland have reached or are reaching the ends of their lives, which raises issues about rehabilitation. Significant volumes of 'cleanfill' are generated by the City, particularly during phases of urban renewal and development. Emplacement of the fill in quarries removes the problem of fill disposal and provides an opportunity for restoration of the quarry site.There is a compatibility between quarrying and cleanfilling because at quarries:Truck routes are already established Neighbours are accustomed to the effects and appropriate buffer distances have been established Bringing fill into a site attracts aggregate sales and is very efficient. Fill originates from construction sites and ad-hoc excavations and therefore it is not surprising that sampling has shown the quality to be variable. Both Winstone and the Auckland Regional Council have surveyed undisturbed soils in the region to attempt to determine natural background levels of common contaminant substances. Comparison of these levels with delivered fill shows that a high proportion of delivered materials can be regarded as mildly contaminated. Therefore the term 'cleanfill' is, in the Auckland region at least, a misnomer and the term 'managed fill' has been adopted.Historically and presently the only control on quality of 'cleanfill' has been some visual inspection. This leaves the fill operator open to potential liability for creating a contaminated site. Implementation of controls at WinstoneÆs operations has progressed slowly, over some ten years. This is mainly due to the perception that mobility of contaminants within and out of the landfill will be very limited because of the near-neutral pH and abundance of clay minerals in the fill. The methods of control and results of environmental risk assessments at WinstoneÆs Puketutu Island Quarry will be briefly described.

Jan 1, 2002

By S Dunham

A cross-discipline approach combining geology, metallurgy and mine planning, geometallurgy is seen as the next logical advance in improving the design and operation of mining businesses. This rapidly evolving field is focused on realising the value that has often been lost in the chasms between the aforementioned technical silos. When successful, the geometallurgical approach promises the ability to tailor mining and mineral processing development and operational options more closely to the characteristics of the resource with resulting lower costs (both capital and operating), improved recoveries and fewer project failures.As with any technological (or managerial) change, there will be side effects from the success of the geometallurgical approach that will impact areas beyond obvious linkages between geology and processing. Some of these effects have the potential to be beneficial to the resource industry and society in general. Beyond the basic geometallurgical promise of closer alignment between processing design/strategy and the multivariate 3D spatial characteristics of the mineralisation, this paper discusses the broader implications and ramifications of the emergent geometallurgical approach: enhancing exploration and discovery; improving project development success; achieving sustainability in an industry working with non-renewable resources; in a world of increasingly hard won license to operate, improving the management of potentially harmful by-products and waste materials (with knock on effects for proactive management of closure issues); smarter approaches to energy management and thus optimisation of projects with respect to carbon footprint; and potential to re-value assets and thus realise a strategic advantage in the area of acquisitions, divestments, mergers and take overs. The authors strongly believe that companies that actively engage with the above issues (and ensure that technical efforts in the area of geometallurgy are not isolated from the larger value chain activities of the firm) will be able to exploit the opportunities that consequentially arise. These early adopters will gain first mover advantages. Firms taking the broad view of geometallurgy will have an opportunity to maximise stakeholder value and win greater success than their less insightful competitors.

Sep 5, 2011

By J F. Carswell, G Cheshire

The Pajingo gold operation in Queensland is approximately 55 km south of Charters Towers and 134 km south-west of Townsville. The gold deposit was discovered on the northern end of the Drummond Basin in 1983 and first open pit production began in 1986. Mining progressed underground in the 1990’s and gold production peaked in the early 2000’s as the main Vera/Nancy lodes were extracted, producing 330k oz in 2003 (a record at the time). More recently, as Ore Reserves and grade have diminished, the mine has had to develop innovative mining practices to maximise recovery of the remaining Mineral Resource. This has included a modified sublevel caving method against previously mined/backfilled zones. The method has been coined modified sublevel shrinkage (MSLS). Full scale trials of the new mining method have been successfully completed. This has allowed the site to revaluate the Mineral Resource and include areas into the Ore Reserve that were once deemed sterilised, adding significant value to the operation and extending its life-of-mine. This paper describes the first of two large scale MSLS trials and key operational learnings from it.

Mar 15, 2021

Grey River Gold Mining Limited (GRGML) has constructed and largely completed the commissioning of an alluvial gold dredge designed to recover gold from a low grade gold deposit in the Grey River Valley, New Zealand. The most important resource that GRGML has are the people who are employed by the organisation. The low grade of the deposit necessitates the requirement to operate the dredge at optimum efficiency, which in turn requires the work force to be of high calibre and continually motivated. The primary prerequisite for employment at GRGML is for employees to be receptive to new ideas and have the adaptability to develop new skills and apply those skills to the changing demands of the workplace.   A continually changing organisational structure is utilised to meet the needs of a changing work environment. The adoption of an innovative site employment agreement allowing for flexible working hours has aided the achievement of good employee productivity and attendance.   Employees gain a higher quality of life by working a roster pattern involving twelve hour shifts and a four day on, four day off pattern.   Employees and management are communicating very well and working together to achieve organisational goals which will ultimately benefit the employees, the shareholders, the local community and the mining industry generally.

Jan 1, 1989

By Peeler P. K

The recent renewal of interest in hydrometallurgical routes for copper production has been brought about by the possible future reliance on mixed ores and lower grade deposits, environmental aspects, and energy considerations.A number of hydrometallurgical processes for the recovery of copper have recently been proposed. Flowsheets are developed for two processes which incorporate several treatment methods being experimentally studied in Australia.In the first process a cupric chloride leach is followed by electrowinning whilst the second is based on the formation of cuprous ions, stabuized by acetonitrile and subsequent disproportionation to cupric ions and metallic copper. For the purpose of comparison, flowsheets were also developed for the Arbiter and Cymet processes.Process economics are estimated for the four processes and the results are discussed in relation to competitive pyrometallurgy. None of the four hydrometallurgical processes, with possible exception of the Cymet process, appears to be competitive with established large scale and newly developed pyrometallurgical processes for chalcopyrite.However, because the economics of the individual hydrometallurgical processes depend strongly on specific conditions, a "tailored" process may be competitive with pyrometallurgy in particular circumstances.

Jan 1, 1977

By N Currey, G Corder, G Becker

"The SUSOP« Framework is a new technique that helps incorporate sustainable development principles and objectives into the design and operation of businesses. Developed through the Co-operative Research Centre for Sustainable Resource Processing, it brings a design methodology to sustainability, similar to what hazard and risk techniques such as HAZOP did for safety.Metallica Minerals Limited (æMetallicaÆ) adopted the SUSOP« framework to help identify opportunities and risks that could directly improve or affect its flagship SCONI (nickel-cobalt and scandium) project. This project has the potential to become the worldÆs largest producer of scandium oxide (æscandiaÆ) which is used in solid oxide fuel cells and strengthens aluminium alloys. Located northwest of Townsville in Queensland, the plant site will be located within the previously mined and partially rehabilitated Greenvale Nickel Mine. By applying the SUSOP« framework through a series of multi-disciplinary workshops and offline analysis, Metallica was able to identify numerous sustainability opportunities and risks. Opportunities were clustered together to form concepts to develop a more holistic understanding of the projectÆs overall potential contribution to sustainable development as well as determine where key risks could be mitigated. Four key concepts were identified: Waste and Water Workforce Community and Enterprise Development Energy and Greenhouse Gases (GHG). Metallica was able to include a range of initiatives that could deliver enhanced environmental, social and community outcomes into their mine development plan. These included measures to reduce reliance on water, reduce the volume of waste, provide local opportunities for training and skilled employment and create support for local enterprise development. These measures also resulted in a significant reduction in the capital estimate of the project.This paper provides an overview of the SUSOP« framework, details its application to the SCONI project and discusses the outcomes that will help establish the projectÆs strong sustainable development credentials and improved business outcomes.CITATION:Corder, G, Currey, N and Becker, G, 2013. Sustainability, made easy - A business improvement case study, in Proceedings MetPlant 2013, pp 259-271 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 15, 2013

By Elliott A, Kingsnorth D. J

The development of a large high grade spodumene orebody, in excess of 30M tonnes containing at least 7M tonnes at 4.0% Li20, by Lithium Australia Ltd at Greenbushes, Western Australia is significantly increasing the world consumption of lithium minerals. The availability of two low cost sources of lithium, spodumene concentrates (7.5% Li20) and glass grade spodumene (4.8% Li20) has been welcomed by the ceramic and glass industries as it assists them to lower their raw material costs at a time when they are facing severe competition from alternative materials. While there is no shortage of lithium reserves in the world, there has been a shortage of high quality lithium minerals. The Lithium Australia development has filled this need. The favourable factors of high grade, low impurities, open cut mining and existing infrastructure make this an ideal low cost source for a long term downstream lithium industry. The Lithium Australia mine development has filled the need for a reliable long term supply of lithium minerals. The long term viability of this resource is ensured by the unique combination of the following key attributes of the development : High grade reserves of 7.OM tonnes of 4.0% Li20 within 130 metres of the surface, contained within a total proven reserve of 30M tonnes of 2.8 % Li20. Open pit mining with stripping ratio of less than 2.5:1 waste:ore. Low impurities levels, particularly in those elements, that have a detrimental effect on the colour of glass/ceramics i.e. iron, manganese, titanium and chromium. An existing mine infrastructure that includes an adequate water supply for all foreseeable processing requirements. A sophisticated spodumene concentrator utilizing statistical process control to produce a consistently high grade product with minimal impurities. A technically qualified stable workforce fully acquainted with spodumene processing techniques. Greenbushes high grade concentrates have found ready acceptance in the specialty ceramic and glass industries during the past four years. The consistency and high grade/low impurity level of the product has enabled its use in the production of television tubes, oven to table ware, glass fibres, specialty glasses and ceramic glazes.

Jan 1, 1989

By S Worden, P A. Kirsch, A Kirsch

Despite the current downturn, coal remains an important commodity in the Australian economy. Increasing coal resource development has resulted in increasing competition for land use in coal mining regions across the country with communities and other stakeholders becoming more adept at articulating their concerns regarding this competition in a range of traditional and social forms of media. In this environment, obtaining and maintaining a social licence to operate (SLO) is problematic and has been identified as the fourth greatest risk facing the international mining industry.This research presents the findings from a longitudinal study on how Australian newspapers frame the views of coal mining stakeholders across each stage of the coal mining life cycle. News stories from national, state and regional newspapers in 2000, 2006 and 2013 were analysed.Over the study period, there have been significant changes in the coal mining themes being covered by Australian newspapers, the number of stories being published, the number of newspapers covering coal mining stories, and the diversity of stakeholders being quoted. How do the dominant themes in media communication change over time? How do these changes impact mining across the life-of-mine?The research confirmed that Australian journalists use framing, priming, labels and bias to conceptualise and understand the events that they report, and that this behaviour has a profound effect on public opinion.CITATION:Worden, S, Kirsch, A and Kirsch, P A, ?2014. Moving beyond economic framing of the Australian coal industry, in Proceedings Life-of-Mine 2014 , pp 365–376 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

A homely simile will serve to epitomise an interpretation of the rock structures and associated phenomena of the block of country under review, as it appears to the writer.Disregarding the many thousands of feet of overburden that have been eroded away during the ages, the present denuded surface and rock systems below may be pictured as a slab of some titanie ribbon cake that has suffered much damage from rough handling and exposure, yet retaining much of the original symmetry of its superimposed layers of variegated colour and texture.Lateral pressure has crumpled the cake into a series of irregular corrugations and, in parts, has caused some of the layers to crush and slide over their neighbours.Following upon this squeeze, the cake has been severed into segments and rhomboidal slabs by vertical cuts, and these portions have been severely jostled one against its neighbour, crushing the faces of contact and dragging the contiguous layers in the direction of movement.The variegated icing of the cake is represented by intercalated sills of amphibolite, pegmatite, and aplite, and the body of the cake by highly altered sedimentary rocks.The icing has been assailed by the rats of erosion with such effect that only residuals of the original structures remain. The body of the cake has suffered successive waves of igneous invasion in the order of lode pegmatite, followed by zine, iron,copper, and finally by silver-lead. These successive invaders found difficult access, along certain of the vertical cuts, to the more succulent layers of the cake, where, gorging to repletion, many were imprisoned and entombed for the future service of mankind.

Jan 1, 1927

By G T. Kukla

A Seam deposit User oriented Mine Planning System (SUMPS) was developed by The Broken Hill Proprietary Company Limited (BHP) at its head office in Melbourne. It is one of the computer mine planning systems developed by the Corporate Data Processing (CDP) section of BHP. To date it has been employed in the feasibility study of four coal prospects for the BHP Group, including Gregory in central Queensland û Ham and Van Hoorn (1978). It was also used in detailed short term mine planning for Gregory. A recent application was in the feasibility study of Saxonvale, a multi seam coal deposit in New South Wales with seams up to 20 m thick. The other two applications of SUMPS were also on thick multi seam coal deposits. Development of programs for the underground subsection of SUMPS is continuing. SUMPS was developed and implemented on mini computers with graphics and plotting peripherals. The company's philosophy towards computing is one of centralized development and project planning, with transfer of hardware and software to site once the mine becomes operational. Support of the site's system continues from head office which is continually involved in development of SUMPS and issuing revision updates to sites. The users, as well as programmers, were mostly geologists and mining engineers. This helped to ensure rapid, successful implementation. The broad approach of this system was to use interactively the specialist skills and interpretative abilities of the user mining engineers and geologists with the data manipulation abilities of the computer. It is an integrated system which covers geological exploration, deposit modelling, mine planning and production scheduling. An important feature of the system is that the user has full interactive control over each function through a graphics terminal where applicable.

Jan 1, 1980

By D Mcleod, S Brindley, S Green

The design and engineering of flotation circuits is driven by numerous inputs, including (in no particular order) testwork outcomes, site considerations, type of separation required, energy sensitivity of the flotation response, personal experience and preference for flotation machines, maintenance access requirements, operability, level of automation and capital constraints.This paper discusses these and other issues in the Australian context and covers the flotation of copper/gold ores and polymetallic (copper/lead/zinc) ores. The paper discusses aspects of the following: how should testwork be done and what are the important inputs and outcomes? how should testwork results be interpreted and how does this impact on equipment selection? what processes can have a critical impact on flotation circuit performance, eg thickening and regrind? what options are available with the typical æflatÆ Australia site? how do you minimise capital cost and what impact can this have on flotation circuit operation and maintenance? how should circuits be controlled and operated? Particular focus is placed on some practical aspects of process design and engineering and the potential impact that engineering decisions can have on flotation plant operation.

Jan 1, 2005

By H He, S Tillotson, S Gibbons, J Shaw

"Water evaluation and management during mining exploration and operational activities is crucial to minimise direct and indirect operational costs and also in delivering mining companies the less tangible, but equally critical æsocial license to operateÆ.Mining is often carried out in remote areas, where the mine will be the most significant and visible user and potential contaminator of water resources. However, wherever it is located, a mineÆs use of water must be managed in the context of two key aspects: the natural parameters of the resource; its abundance, its temporal variability and its chemical and physical qualities other users of the resource; other industry, potable water supplies and ecological requirements of local habitats.It is vital, therefore, that this commodity be assessed to an appropriate degree to help establish the viability and sustainability of the mining project and identify those other stakeholders who may be affected by the mining companyÆs activities.This paper outlines the background to catchment-scale model and presents a cost-effective method for establishing a robust water baseline and creating a water management tool to be used throughout whole mine life cycle. Numerical surface and groundwater modelling has long been established as a tool for reactive management, following collation of yearsÆ worth of data. Now, using freely available remote sensing data and desk study information, analytical modelling techniques can be used cost effectively to provide mining companies with a tool for assessing and managing their water consumption requirements at the outset of a new project venture.The paper includes a selection of case studies to show how the use of analytical modelling can be used as an evaluation and management tool to help not only assess general watershed parameters and water availability but also how it can be used as a tool to provide decision makers with the information to complete æwhat if?Æ scenario assessments. The case studies illustrate how a combined hydrological and hydrogeological model may enable identification of sensitive receptors, water competition issues and contaminant migration pathways to help manage the risks associated with water consumption and its potential contamination from exploration and operational activities.CITATION:Gibbons, S, Shaw, J, Tillotson, S and He, H, 2013. Catchment-scale water modelling and its role in risk management during mining exploration, in Proceedings Water in Mining 2013, pp 175-188 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 26, 2013

By C M. Wawryk, S L. Garwin, J D. Foden

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Batu Hijau porphyry Cu-Au deposit in south-western Sumbawa, Indonesia is an ideal natural laboratory to study the fractionation of iron isotopes in magmatic rocks that range in composition from basaltic andesite to tonalite. Intrusive rocks are associated with a porphyry system that contains well-preserved early hypogene copper mineralisation. We analysed pre-, syn- and post-mineralisation igneous intrusive rocks. We also separated magnetite, chalcopyrite and bornite from hypogene porphyry-style quartz veins, and measured the Fe-isotope ratios of samples by solution multi-collector ICP-MS. Iron isotopic composition of samples from the magmatic suite show an increasing d57Fe with increasing SiO2, supporting geochemical and textural evidence that the Batu Hijau Tonalites underwent closed system fractionation. Equilibrium and co-existing mineral textures allow the calculation of the following preliminary empirical mineral-mineral fractionation factors at 500°C for certain mineral pairs.Iron isotopes have the potential to provide geothermometric data to complement fluid inclusion data, especially where heating stages have operational limitations and where fluid boiling results in a wide variety of inclusion types that may make analysis difficult.CITATION:Wawryk, C M, Foden, J D and Garwin, S L, 2015. Iron isotope fractionation in magmatic-hydrothermal minerals – a porphyry copper case study from the Batu Hijau deposit, Sumbawa, Indonesia, in Proceedings PACRIM 2015 Congress, pp 389–396 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

Support design in jointed or blocky rock masses is often approached by the use of either 'rules of thumb', rock mass classification systems such as the Q-system (Barton, Lien and Lunde, 1974) or RMR (Bieniawski, 1973) or conventional wedge analysis. Generally, this requires that a number of key simplifying assumptions are made and the support system is designed to cater for either a mean, most likely, or worst case scenario depending on the risk tolerance. The design block size is often a major uncertainty and often a worst case block size based on excavation span is used. Thompson and Windsor (2007) state that it is inappropriate to base support designs on the excavation size as these size blocks rarely occur if discontinuity trace lengths are considered. Probabilistic keyblock methods can be used to determine the most likely design block sizes. A methodology is presented whereby JBlock software (Estherhuizen, 1996) is used to estimate potential block sizes as part of the support design process. Using information such as the spacing, orientation and length of discontinuities, it is possible to simulate blocks in the walls of an excavation (Esterhuizen and Streuders, 1998). Keyblock analysis methods (Goodman and Shi, 1985) are used to evaluate whether blocks are removable and whether the chosen support will be sufficient to ensure stability. Data from two mines is used to demonstrate how probabilistic keyblock analyses can be used in support design. Discontinuity data was used to generate 10 000 removable blocks and the design block size statistics were determined. For one mine this information was used to scale blocks in a conventional. Unwedge analysis whilst for the other mine, the point estimate method (Harr, 1987) was applied. The choice of appropriate design acceptance criteria in terms of factor of safety and probability of failure is also considered.

Nov 25, 2010

By Bujtor G. J, McMahon D. W

This guide to the understanding of ore reserve estimation is the revised version of a report with a similar title circulated within the CRA Limited (CRA) group of companies in mid-1980. It is the principal result to date of an Ore Reserve Study commissioned by CRA in late 1977.This guide to the understanding of ore reserve estimationis the revised version of a report with a similar titlecirculated within the CRA Limited (CRA) group ofcompanies in mid-1980. It is the principal result to dateof an Ore Reserve Study commissioned by CRA in late1977.The study was prompted by two ore reserve situations.The Zinc Corporation and New Broken Hill Consolidated,Broken Hill, had reached the point of havingto find a replacement 'for their traditional ore reserveprocedure and Mary Kathleen had to admit publicly thatore reserve predictions would not be realized. Thesewere not however the only problems to be looked at. Asmentioned more fully later, other ore reserve situationswere known, or were met during the study, in copper,gold and nickel as well, where poor realization: expectationratios had ranged from embarrassing to disastrous.These made it clear that ore reserve estimation had to belooked at afresh.The fresh look has resulted in a broadening of theconcept of ore reserve estimation from its traditionalpurely computational basis to an approach embracingall the many things that can affect expectation andrealization as essential factors. Hence this guiderepresents a gathering together of what has been learnedand what should be known to all those concerned withore reserves in any of its diverse aspects.The study has been marked"by a number of changesof thinking. At first the aspects that appeared to requireattention were two; recognition that an ore reserve statementwas an estimate, not a precise calculation; and asearch for im improved estimation procedure adapted tolow grade ores with narrow economic margins. Threeyears later the view was that the need was to incorporateinto ore reserve estimation all relevant aspects of theproposed mining operation from choice of a samplingmethod to sales contract specifications.This study is thought to be unique in being frankabout weaknesses in ore reserve estimation and intreating failures not as natural disasters (like drought orflood, which have to be endured) but as potentiallyavoidable. It has led to three principal conclusions.

Jan 1, 1982

By S H. Begg

There is strong evidence that many major oil and gas (O&G) projects are plagued by large cost and schedule overruns, or significant underperformance in productivity. Similar evidence exists for large mining projects. This paper claims that uncertainty is the underlying reason why projects fail to deliver the metrics used to justify their investment, or to deliver the economic value possible if alternative decisions had been made.Most technical and economic analyses are performed to reduce uncertainty to help make decisions. Decision-making is about ranking alternatives and choosing the best; rarely are precise predictions required, if this is even possible. Better uncertainty assessment is one of the keys to better decisions, thus better business outcomes. To get better decisions it is suggested that the focus or reward/penalty incentives be shifted away from the quality of outcomes to the quality of decisions. High-quality decisions are those that are generated from the skilled use of the tools, methodologies and processes from the discipline of decision analysis.Uncertainty is quantified by probability, which is a degree of belief in the truth/falsity of some proposition about a quantity relevant to a decision, such as volume of in-place resource, future price or action of a competitor. The probability a person ascribes to a proposition depends upon their information set; hence probability is subjective – it is not an inherent attribute of the quantity of interest or the physical system.The above simple observations have profound implications for modelling approaches, how they deal with uncertainty, the use of data to help assess uncertainty and the reliability of information provided by subject-matter experts. The limited circumstances under which frequency data (from spatial or temporal variables) can be used to assign probabilities is also reviewed.People, in general, are subject to a range of biases and cognitive errors. Research with O&G subject-matter experts shows that their expertise offers little or no protection from making errors in probability assessments and other judgements.CITATION:Begg, S H, 2016. Decisions, decisions – uncertainty, variability, modelling and psychology, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 9–18 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

Purification of Nickel and Cobalt from Heap Leaching Effluents Using Ion Exchange Resins A comparative study among several chelating resins for purification of a heap leaching effluent from a nickel laterite ore has been finished. Chelating resins with iminodiacetate (IDA) and bis-picolylamine (Bis-PA) functional groups, from different suppliers, have been evaluated for their selectivity and loading capacities for nickel and cobalt over impurities. The two evaluated IDA resins, Amberlite IRC 748 and Monoplus TP 207, showed very similar results for both loading capacity and selectivity. Better performance was obtained at 7 BV/h at a pH of 4. Evaluation of Bis-PA resin showed that XUS 43578 has better performance than TP 220, with a 30 per cent higher loading capacity and superior selectivity for nickel over impurities.

Sep 13, 2010