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During the last 12 years the dominant theme at Mount Isa has been production expansion. Production rate of 3,200 tons per mine day in 1953 increased to 11,000 tons per mine day in 1960, completing the first stage of the programme. The second stage is still in progress. It is planned to increase production of lead and copper ores to 19,500 tons per mine day in 1968.Current mine workings comprise an area 2 miles long and 1/2 mile wide, the deepest production level being 2,000 ft below surface. During the next 10 years it is anticipated that mining will be carried out to a depthof 3,200 ft below the surface. The rapid extension of the mine has necessitated frequent re-appraisals and modifications to the primary ventilation system, and a system with considerable in-built flexibility has gradually evolved. Since 1953, volume circulation has increased eight-fold to approximately 2,400,000 c.f.m.To suit various mine operating requirements, a combined pressure-exhaust system of ventilation was adopted.The usefulness of this system is at a maximum when the fans installed permit ready changes in the location of the boundary between adjacent spheres of fan influence.Air flow through openings to the surface can be controlled or used as required. This feature is considered necessary for a mine where underground workings are comparatively shallow and caving to the surface willoccur.A major heat problem exists due to climate conditions, high geothermic gradient (one degree Fahrenheit in 95 ft), and oxidation in leached and brecciated areas.Because of this, quantities of air far in excess of the minimum requirements for dust removal are required to ensure satisfactory environmental conditions. In assessing fan pressure, consideration was given to 1. the mine resistance, and the requirement for pressure differential capability,2. the pressure requirement for deeper mining, with due allowance for booster fan use where appropriate,and3. the desire to avoid fan operation at pressure duties above the region of peak fan efficiency.The latter feature provides a safety margin between maximum operating pressure and the stall point of the fan.

Jan 1, 1967

By F H. Henrfquez, A G. Oroz

Design and operating conditions of large size mechanical flotation cells were evaluated by comparing them with actual operating conditions in a plant. The objective was to determine the time scale-up factor, typically based on empirical rules. Experiments were conducted on the rougher flotation circuit at Minera Escondida Ltd. The circuit consisted of self-aerated mechanical cells of 160 m3, arranged in six parallel banks with nine cells each. The rougher circuit flotation kinetics were evaluated from direct sampling and local mass balances around each cell of the bank. Adjusted overall mass balances were also developed. This information was used to fit different kinetic flotation models, and it was found that the rectangular distribution function was the most appropriate to describe the distributed rate constant for industrial operation. Then, a rougher flotation simulator was developed to describe the actual operation in terms of the operating variables (mass flowrate, solid percentage, feed grade) and the actual volumetric flowrate entering to each cell. In this study feed pulp samples were taken in parallel from the rougher circuit and were simultaneously floated in the laboratory. The kinetic behaviour was then modelled at a laboratory batch scale in order to determine the time scale-up factor between laboratory batch flotation data and industrial size flotation. The time scale-up factor observed for large sized cells, 160 m3, was found to be reasonably similar to those previously determined for self-aerated mechanical cells, but of lower size, operating at similar recoveries. In addition, the relative effect of mixing, between laboratory batch and an industrial flotation bank, was quantified by the parameter, separating the impact that kinetic and mixing changes have on the time scale-up factor. In general, the rougher flotation operation was found to reach the predicted metallurgical target, and the optimal separability criterion was also respected. The diagnostic generates information about the internal state of the process and helps to identify potential improvements for design, operation and control of the circuit.

Jan 1, 2005

By A Kobzev, C Robben

Sensor-based particle sorting of gold ores is the masterclass of preconcentration. The technical challenges of a grade in ppm scale makes a direct detection with currently available technology in milliseconds impossible. Consequently, the detection and classification of particles into ore and waste classes relies on detectable proxies which are the foundation for the classification. These must be reliable and repeatable across the ore bodies processed in future. A sensor-based particle ore sorting equipment must therefore be calibrated systematically by understanding the gold deportation in different lithological groups. Also, it must be in best operational state to minimise possible misplacement. The technical challenges are met by a stringent financial regime governing the business case. Many gold ore sorting projects require a stable grade of gold in the rejected waste significantly below 1gr/t. Two examples are introduced in this paper:  The pilot results and operational experience of X-ray transmission (XRT)-based particle ore sorting for pebble sorting of sulphide associated ore;  Laser-based particle ore sorting for pebble circuit of an orogenic, quartz associated gold ore. Usually, sensor-based particle sorters are installed in the crushing section of a plant. However, for large capacity plants, the number of equipment required, and the associated material handling costs result in significant capital and operating expenses for plants with 1200tph run-of-mine capacity. As a conclusion, it was decided to investigate sensor-based particle ore sorting applied to the pebble stream of two existing semi autogenous mills.

Nov 10, 2020

By I Swane, R Rait, A Robertson

Geochemical assessment of mine waste materials prior to commencement of a proposed mining operation is a fundamental component of mine feasibility studies and the regulatory approvals process. Static and kinetic geochemical test methodologies are widely used to predict the geochemical nature of mine waste materials and to develop strategies for managing potentially æhostileÆ materials. These data can also be integrated with data from other fundamental studies such as hydrogeology to predict specific environmental outcomes and potential impacts at mine closure and post-closure.A case study is presented for a proposed open pit gold mine in Mongolia, which illustrates how geochemical, hydrogeological and groundwater quality data can be used as part of a geochemical modelling process to predict the final pit lake water quality over time. A series of static and kinetic test geochemical test programs were completed and acquired data integrated with hydrogeological and groundwater quality data provided by the proponent. A widely used geochemical modelling program (PHREEQC) was used to develop the geochemical model and predict water chemistry in the pit void after mine closure. Sensitivity analyses were completed to explore the effects on the model output of groundwater to leachate water ratio, pit wall rock type and climate.Modelling has indicated that pit void water should be pH circum-neutral at mine closure and should remain within Mongolian and World Bank water quality guideline limits under the modelled simulation most likely to occur in the field. Final void water salinity is expected to increase eight fold over 14 years after end of mine life due to a continuous flux of salts (particularly sulfate salts) into the pit lake whilst the pit lake volume will remain relatively constant due to evaporation and a slow recharge rate. Dissolved metal and sulfate salt concentrations in pit water are also predicted to increase over time and could be moderately elevated compared to applied water quality guideline values. Some of the metal concentrations, however, may be lower as these would be expected to precipitate at circum-neutral pH and greater. Recommended additional assessment work on the project when mining commences includes determining the magnitude of adsorption and co-precipitation of metals occurring in the pit void water/sludge system.CITATION:Robertson, A, Rait, R and Swane, I, 2013. Geochemical assessment of mine waste materials and prediction of final pit lake water quality at a proposed gold mine in Mongolia, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 165-170 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

By B Saunders, J Carpenter

PanAust’s Phu Kham copper-gold operation (Phu Kham) in Laos is currently limited by throughput in the Semi Autogenous Grinding (SAG) mill. The ability to accurately predict SAG mill throughput (throughput) is therefore critical to accurately forecast copper and gold production. During the fourth quarter of 2016 the proportion of hard unweathered rocks in the mill feed increased, resulting in a period of lower than expected throughput. These low throughput rates prompted a study with the aim of identifying a practical solution for throughput predictions. The study identified an empirical modelling approach based on actual SAG mill throughput rates. The empirical model was then optimised by linear programming to identify the ideal feed blend of unweathered rocks to achieve a maximum SAG mill throughput.Rock strength was the initial focus of the throughput study at Phu Kham because previous studies had identified a strong link between rock strength and throughput. It was determined that there was insufficient valid data to adequately model but sufficient data to qualitatively characterise rock strength. The data identified that the weathering and lithology had a controlling influence on the rock strength. Complicating throughput predictions were operational improvements (changes to blasting and mill settings) implemented in response to the lower than expected throughput. This created uncertainty with the throughput equations. A self-learning empirical modelling method was developed to predict the throughput by incorporating fundamental rock properties with operational practices and improvements. The method is based on the proportion of mill feed with similar weathering and lithology (a proxy for comminution performance) and the actual mill throughput using the SAG mill as the analytical instrument. The modelling method simultaneously incorporated the sum and interaction of unmodelled influences including blasting, crushing and mill settings. The empirical modelling method worked at Phu Kham because the lithology and weathering has an intuitive and observable controlling influence on SAG mill throughput. The modelling method is described along with a worked example of feed blend optimisation using linear programming.CITATION:Carpenter, J and Saunders, B, 2017. Empirical mill throughput modelling and linear programming for blend optimisation at the Phu Kham copper-gold operation, Laos, in Proceedings Tenth International Mining Geology Conference 2017, pp 291–296 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By MáAndrusiewicz, M M. Hilden, M S. Powell, P D. Kay, B Foggiatto

Circuits with unconventional and potentially more complex designs are predicted to become more common in the future as plant designers and operators look to process ores more efficiently. Ideas have been presented on how circuit design may be changed to utilise todayÆs technology to address tomorrowÆs challenges (Powell and Bye, 2009; Powell, Benzer and Mainza, 2011a). High pressure grinding roll (HPGR) installations in various configurations; application of preconcentration plants eg sorting, magnetic or gravity separation; and preweakening devices eg microwave processing; are all examples of technologies having the potential to deliver a significant reduction in comminution energy for ores amenable to these processes. Not only will future novel circuits contain equipment for which models are not as well developed (if at all), many will likely require the ability to respond to variations in feed, and interact with geometallurgical models requiring process adjustments when the ore characteristics change.In order to confidently simulate more complex circuits and accommodate variations in feed type, a significant advancement in modelling and simulation capability is required. This includes dealing with multiple components in the feed, accommodating different competencies of ore, utilising physical separation opportunities and tracking the grade reporting along the different potential processing routes. Developing the means to simulate complex circuits has been a key priority of a collaborative group of comminution researchers working to solve these challenges.Simulations are presented utilising a new configurable simulation interface called the model developers kit (MDK). The MDK is designed to accommodate multi-components and incorporate new models under development. These will be used to demonstrate the potential of flexible circuit design, based on measured ore properties and equipment performance.CITATION:Foggiatto, B, Hilden, M M, Powell, M S, Kay, P D and Andrusiewicz, M, 2012. Simulation of flexible circuits, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 291-298 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

Our modern cities are almost incapable of sustaining themselves without subsurface infrastructure, which is not identifiable at first glance. This very soon becomes evident when the chaotic conditions prevailing in some cases in the multi-million cities on the African, Asian and South American continents are taken into consideration. This does not simply apply to the hopelessly congested streets in the downtown areas. If anything, it is shown here too that a subsurface infrastructure represents an important prerequisite for public health right up to banishing the danger of disease. Even during the 1990s, this has been clearly underlined through examples of cholera and plague epidemics in parts of Central and South America as well as on the Indian subcontinent. The overriding significance of an inner urban subsurface infrastructure in order to create decent conditions in the major built-up areas was once again emphasised not all that long ago at the United Nations HABITAT-II Conference in Istanbul, Turkey, in June 1996. More than 15 000 delegates from all over the world mulled over and discussed the prerequisites for humane living conditions in human settlements taking the varying climatic, topographical and cultural marginal conditions in different regions of the globe into account. Apart from the built-up areas themselves, the utilisation of underground space is experiencing high and ever increasing significance in less densely populated regions. Attractive and fast transport links between industrial centres call for high- performance transport arteries for the economic, speedy and unhampered carriage of people and goods. Important impulses for the economic power of a region or nation are provided by transport development and links. As a consequence, tunnels for roads and railways are being built or planned to a great degree for crossing mountain ranges, rivers and straits.

Jan 1, 1999

By J Rutter, D La Rosa, P Walters, M Scott, L Keeney

Bulk ore sorting technologies, whether surfaced based or penetrative, have seen an increased uptake by the mining industry for preconcentration application. As with all technologies, going through the technology validation process is key to de-risking the operationalisation of the technologies and to demonstrate and confirm predicted value propositions. The ability to laboratory calibrate cross-belt bulk sensors is standard practise for sensor vendors, however transitioning the technology from laboratory to real-world application is a non-trivial process. The industry has taken two main approaches to trialling and validating bulk sensing technologies in operational environments, namely:  Construct an off-line pilot facility at scale, or  Install bulk sensing systems on production conveyors Each of these two approaches have significant advantages and disadvantages and require different experimental design programs and analysis methodologies. Consideration of material movement, heterogeneity degradation, logistical requirements, and financial investment all factor into which approach is most suitable for an evaluation scenario. CRC ORE in partnership with mining companies, have conducted several bulk sensor pilot trials utilising different sensor technologies employing each of the two main approaches outlined above. This paper describes the challenges faced, learnings obtained and outlines a position on how to transition bulk sensing technologies from the laboratory into the operating environment. The case studies presented cover a range of commodity types in both open pit and underground operations.

Nov 10, 2020

By M Watkinson

Tube bundle monitoring systems have come a long way from their first introduction to coal mining in the late 1960s/1970s. Early developments in the United Kingdom (UK) commenced with single gas analysers (carbon monoxide) and quickly moved towards introducing oxygen analysers and methane analysers for improved analysis, in particular the calculation of air-free results. Recommendations were made in the early days as to how and where to run tubes and on the matching of sample pump and purge pump pressures. Current Australian installations are commonly based on a four-gas multianalyser, infrared for carbon monoxide, carbon dioxide and methane, and paramagnetic for oxygen. These systems are controlled with programmable logic controllers (PLC), with component monitoring as an integral part of the software. This paper discusses the development of tube bundle systems from the 1960s to the current date and looks at the advantages and disadvantages of the installations, along with making operational recommendations to be considered with the siting of the analyser building, running of tubes and maintenance of the system.CITATION:Watkinson, M, 2015. Developments in tube bundle gas monitoring, in Proceedings The Australian Mine Ventilation Conference, pp 259–266 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By M D. Sussman

A large number of countries in the world now have some regulation for labelling the presence of genetically modified organisms (GMO) in food. For the last ten years, ISO/TC 34/SC 16 has been providing methods, guidelines and requirements concerning the evaluation of molecular biomarkers including GMOs. This activity makes sure that stakeholders on all sides of commercial transactions are satisfied and their marketing or regulatory needs are met. Developing and maintaining a transparent, science-based environment for users of horizontal methods for molecular biomarker analysis is a high priority. Sampling and analysis of molecular biomarkers has become critically important for food and agricultural organisations developing, producing, distributing and selling genetically engineered, non-genetically engineered, identity preserved and/or organic crops and their derived products and preventing their respective destructive diseases. To aid in international harmonisation, a new work item proposal to develop an ISO type A management system standard (MSS) for organisations including laboratories using molecular biomarker analysis and sampling has been submitted to ISO/TC 34/SC 16. The purpose of this MSS is ensuring that determination of the presence, absence or quantification of a particular biomarker with a relationship to a product quality determinant, a marketing claim, a regulation or a plant pathogen is carried out under a suitable quality assurance / quality control system. This MSS will provide an overarching system to apply and manage molecular biomarker analysis and sampling for any organisation large, medium or small in a private, government or academic setting.CITATION:Sussman, M D, 2017. ISO/TC 34/SC 16 horizontal methods for molecular biomarker analysis – molecular biomarker analysis and sampling management system, in Proceedings Eighth World Conference on Sampling and Blending , pp 295–302 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By F T. Suorineni

Empirical methods are deeply rooted in geomechanics. This is a consequence of the recognised complexity of the nature of the rock mass. The usual assumptions of material continuity, homogeneity, isotropicity and linear elasticity often assumed for soil, concrete and steel are difficult to justify in a rock mass except for mathematical convenience. These assumptions form the bases for most mechanistic, analytical and numerical methods in geomechanics. Believers in empirical methods argue that the complexity of the rock mass and its interaction with structures developed in it is adequately accounted for in empirical methods, which compensate for our ignorance.Franklin (1993) defines empirical design as quantified judgement based on experience. He further states that empirical methods often prove ‘closer’ to the ‘truth’ than the apparently more precise predictions of theoretical analysis, adding that based on real data empirical methods provide a standard against which theoretical predictions are measured and can be judged. This paper takes a critical look at the common empirical methods in geomechanics – rock mass classification systems (Bieniawski, 1973; Barton, Lien and Lunde, 1974; Hoek, 1994a), Laubscher block caving design rules (Laubscher, 1994), the stability graph (Mathews et al, 1981), pillar design equations (Salamon and Munro, 1967; Hedley and Grant, 1972; and their derivatives), pillar design chart (Lunder and Pakalnis, 1997) and failure criteria (Hoek and Brown, 1980; and its derivatives). The common thread in the application of these methods is that in most cases they are often applied blindly without an understanding of the underlying assumptions and database limits. This paper emphasises that users of these methods need to know the underlying assumptions, database limits and inherent hidden risks that are often unmentionable for their satisfactory use. Finally, suggestions are provided for the efficient use of empirical methods and how they can be improved.CITATION:Suorineni, F T, 2014. Reflections on empirical methods in geomechanics – the unmentionables and hidden risks, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 143–156 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

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

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

Jul 13, 2015

By J Krawcz, S Wasilewski, W Mironowicz

Barometric pressure and its variation in deep underground workings have a considerable effect on ventilation conditions. Pressure changes which create transient states of air flow and air parameters in workings are especially significant. Experiments have shown that pressure changes have a remarkable effect on air parameters at mine workings and hence, attempts to evaluate the scale of this phenomenon are of value. Continuous monitoring of the barometric pressure on the surface of mines allows for the detection of changes in pressure which undoubtedly influence alternations of pressure in the underground areas of mines. Very important factors are the internal disturbances of pressure within a mine ventilation system due to variable conditions of fan operation and the operation of a winding machine where a mine cage moving in a shaft causes piston like disturbances. Local transient disturbances caused by temporary opening/closing of air stoppings due to personnel or underground transport traffic are of importance. The results of over two years of observations of barometric pressure and its influence on pressure variation in underground mine workings are presented in this paper. The observations were possible through the installation of pressure sensors at selected points of the downcast shaft in a mine. Of interest are the observations of the transient states of pressure and other air parameters caused by emergency fan stoppage, movement of a mine cage and changes due to the opening of air stoppings. Data acquired during experiments of opening and closing air stoppings were used for the validation of a flow model in a long working.

Jan 1, 2005

By J E. Everett, F Grobler

This study considers realistic data for a planned open pit iron ore mine, but is applicable to any open pit situation. By interpolating drill hole data, grades are generated for a rectangular block model. Each blockÆs grade designation vector has components for each analyte (chemical element or compound) influencing ore value. Interpolation by means of geostatistical kriging leads to each block being assigned its expected value, and thus underestimates the overall grade variability. Alternatively, interpolation by means of conditional simulation is a method that implements random sampling from an infinite population of solutions. Each conditional simulation has appropriate overall grade variability, but estimating any blockÆs mean and variance requires sampling from multiple conditional simulations. For a block model, an ore/waste selection criterion maximises the expected tonnage at a target grade. This criterion is a linear composite of the grade components, with positive coefficients for the beneficial analyte (iron) and negative coefficients for the deleterious analytes (such as silica, alumina and phosphorus).Although conditional simulation gives the same expected grade as kriging for each block, the expected maximum tonnage of ore selectable at a target grade may differ from that obtainable from the kriged solution. We apply the linear composite selection criterion to each of 25 conditional simulations, as well as to the kriged block model. The resulting distribution of product tonnage is confirmed to have an expected tonnage that is over 20 per cent greater than that of the kriged model. The method also enables a selection probability to be computed for each block, and thus a probabilistic pit boundary distribution to be identified and used in mine planning. Proposed extensions will consider risk-based scheduling of the multiple selection solutions through minimisation of a derived æstress factorÆ and treating the mining process as an iterative system with actual or artificial ædepletionsÆ modelled in line with the mine plan, using the updated state (with new information) to re-evaluate the mine plan for subsequent periods.CITATION:Everett, J E and Grobler, F, 2013. Risk-based ore selection from conditionally simulated block models, in Proceedings Iron Ore 2013 , pp 149-156 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By E K. Chiw, S-M Jung, S M. Masuka, ika

The world reserves of high-grade iron ore have depleted necessitating the need to utilise any existing natural iron ore deposits to meet the demands of the world’s expanding economy using hydrogen in the reduction process to curb CO2 emission. These low-grade ores include iron ores with high phosphorus content. The thermodynamic conditions in the blast furnace allow for the reduction of phosphorus that readily dissolves into the molten iron. Phosphorus in the gaseous state readily dissolves into the molten iron and therefore must be removed due to its negative influence on the mechanical properties of steel. The removal of phosphorus from molten iron is difficult causing the phosphorus to concentrate in metallic iron. The aim of this study is to provide basic knowledge on the phosphorus distribution after reduction using the CO-H2 and possibly provide the optimum conditions for phosphorus partitioning into slag, increasing the probability of its removal by magnetic separation. Total porosity, pore size distribution and surface area of the pellets used were measured using a mercury pressure porosimeter. The reduction was carried out using thermogravimetric analyses (TGA). The reduction rate increased with increasing H2 and was highest when 100 per cent H2 was used. Metal elements distribution in the reduced pellet was clarified using electron probe microanalysis (EPMA) and showed that phosphorus was distributed in the same areas as Ca. More phosphorus was concentrated in slag when 50 per cent CO–50 per cent H2 was used, increasing the probability of dephosphorization using magnetic separation. The concentration of phosphorus into slag was related to the rate of reduction. Further investigations into the reduction kinetics of this ore by CO-H2 is suggested to validate these findings. Nevertheless, a comprehensive thermodynamic analysis of the reduction of phosphorus containing phases found in iron ore with carbon, CO and H2 was provided to assist in selecting the optimal reduction experimental conditions.

Sep 18, 2023

By Reichman J. P

Extensive use is made of a small scale computer (IBM 1130), in the calculations of ore reserves for Western Mining Corporation's nickel mine at Kambalda, W.A. All surface drilling data such as assays, density and location information, are stored on disk files at the Company's Technical Computing Centre at Perth, W.A. The computer is used to search through the data, select significant ore intersections, calculate the area of influence of each intersection and perform the necessary calculations to arrive at an estimate of the ore reserve. Comparing the computer-assisted ore reserve calculation with an entirely manual operation, it is estimated that a saving of 40 percent in time is achieved together with

Jan 1, 1973

ILZRO sights are locked securely on the targets of the expanded applications and ever-improving quality in the major market for zinc-coated steel. A wide range of ILZRO-sponsored research projects examine issues of formability, paintability, and corrosion resistance for traditional hot-dip galvanising, electrogalvanising, and ILZRO's own proprietary zinc coating, Galfan. Recent research has focussed on the on the interaction between Galfan and different substrate steels to determine optimum combinations for different applications. ILZRO enjoys an evolving role in providing the connection between research laboratories and marketing divisions through supporting research and services for the Galfan Technical Resource Centreò(GTRC) and the recently formed North American Galfan Development Authority (NAGDA). GTRC has just produced a new problem-solving manual that provides a comprehensive source of hands-on solutions for the many Galfan licensees throughout the world, and should contribute substantially to the reputation of Galfan as a consistently top-quality steel-coating product. Meanwhile, NAGDA is advancing the market with new advertising for Galfan based on superior corrosion-resistant qualities proven through ILZRO-sponsored research. Practical manufacturing issues remain at the forefront of ILZRO priorities, with research emphasis on cutting and welding zinc-coated steel to provide direct assistance towards improved product quality and a more secure market. Moving to the arena of die casting, when the specifier looks to zinc to fill a design need, ILZRO-sponsored research projects provide comprehensive documentation on metallurgical characteristics for every zinc alloy under almost any imaginable application. On-going ILZRO-sponsored research is integrating this wealth of data with sophisticated computer programs that model die-casting designs with ever-increasing accuracy, as other ILZRO projects lay the market groundwork for zinc in applications ranging from vibration damping to electromagnetic shielding.

Jan 1, 1993

Classification within the Inferred Resource category is based on geological judgement and the balance of extrapolation versus interpolation that the Competent Person is prepared to accept. These resources are typically drilled at spacings well in excess of the geostatistical range and at a density that is non-uniform. In many cases, a substantial proportion of the available data will be historical, and should be considered with more recent data sources. The provision of a robust geological model will increase the confidence in any resource estimate, and should be viewed as a critical component. The definition of Inferred Resources is of great importance to vein gold projects, since Indicated and Measured Resources generally require costly underground development for delineation. Indeed, many gold vein operations possess substantial quantities of Inferred Resources (>75 per cent) in their resource inventory both at project start-up and during production. This contribution explores a number of the key issues when using the Inferred Resource category and presents four recent case studies.

Jan 1, 2006

By D M. Silva, J C. Alves

According to the literature, material transportation represents 50 per cent of the operating costs for an open pit mine. In this context, this paper proposes a multistage approach for dynamic truck dispatching in real open pit mine environments, implemented in the commercial package SmartMine®, marketed by Devex SA. The first stage of this approach defines the optimal number of trucks that maximises the tonnage production by means of a robust linear programming model, which considers the operational constraints of a real mining process. The second stage uses a dynamic dispatching heuristic joining computational simulation and multicriterion optimisation techniques for decision making for truck dispatching. Another relevant contribution of this work is the publication of realistic instances collected from a dispatching system managing an iron mine, containing information about the hauling and loading fleet, the equipment situation when the working shift starts, cycle times, the time line of special occurrences (such as equipment stoppages and loading equipment reallocation in order to satisfy the mine planning) and the tonnage produced. These instances were generated with the purpose of submitting the method to the test of a real situation that considers the uncertainties existing in the process studied. The proposed approach was validated by means of a discrete event simulation model applied to the previously designated instances. Using this multistage approach as a mechanism for dispatch decision making, it is shown that the haulage fleet productivity increased when compared with the real values reported from the instances. These results are important because they show that the proposed approach generates efficient dispatch decisions for trucks operating in a real environment, reducing operating costs, increasing production and making the mine more competitive.

Sep 26, 2011

By R Tooher, S J. Oliver

The operation of copper flotation circuit is a challenging task for the site metallurgists and plant operators. To optimise the performance requires meeting both grade and recovery objectives. These plants have numerous pieces of equipment that are monitored by hundreds of sensors. The challenge is to review these sensors and adjust the numerous control inputs to maintain peak operational efficiency for extended periods. There is also a need to respond to equipment failure. These challenges lead to in operational inefficiencies and can result in a reduction in revenue.This paper details an overview of an operational assistance tool implemented at Newcrest's Telfer plant’s copper flotation circuit. This tool is based on a digital twin of the plant. A digital twin is a model of the plant that is simulated in parallel to the normal plant operation. It is fed with the plant data in real time to provide a prediction of plant operation. The model outputs directly generate the metrics that are used to assess the plant performance, and these are compared with the metrics calculated from the actual plant’s operation. Deviations between the model estimate and the plant’s actual performance are used to gather insight into plant health and alert the operator to poor performance. The operators gather more information regarding the root cause by reviewing the model’s inputs that have deviated outside their normal operating range. An evaluation of the plant performance, following the commissioning of the digital twin, showed an overall reduction of acid soluble copper in the tails.This paper discusses the implementation of a digital twin of the plant to monitor plant performance during live operation. It will include details on data collection and cleansing, data reduction techniques, model development, and real-time implementation. The results of the case study of an implementation of a digital twin at Newcrest's Telfer copper flotation plant will be used throughout the paper.CITATION:Oliver, S J and Tooher, R, 2018. Optimising flotation plant operation by using a digital twin in the control room, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 93–100 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018