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By J Gotte, C Morley, J Froud

Newcrest Mining LimitedÆs Telfer Mine is a world-class gold and copper producer, situated in the Great Sandy Desert, in the north west of Western Australia. The mine has a number of distinctive characteristics such as being one of AustraliaÆs most remote mine sites, being within 270 km of the hottest town in the southern hemisphere (Marble Bar) and having been shut down and reopened after a two-year feasibility study. The construction of a new plant and reopening of the mine gave Newcrest the opportunity to review their mining practices and systems including the opportunity to incorporate reconciliation as a core process. Telfer is now well on the way to being one of the largest gold and copper concentrate producers in Australia. When the mine reopened in June 2003, Telfer implemented SnowdenÆs Reconcilor software system to facilitate reconciliation of geological models, production data and plant measurements. The system was implemented on site in June 2004, as a web-based information management system, integrating other existing mining and plant software packages. It continues to provide an auditable process and consistency of data, providing ease of analysis with standard and customised reporting. This paper provides a case study of the reconciliation system implementation at Telfer. It outlines the consolidation of a number of management systems into one centralised system that can be used to compare and reconcile the tonnes and grades from the mine through to the mill. The authors outline the key estimates and measures that are used for reconciliation at Telfer, detailing the characteristics of the system used to capture the information and the benefits that have been gained through the use of a rigorous reconciliation process on a complex orebody.

Jan 1, 2007

By G D. Matthews, M E. Haylett, S Khosrowshahi, A Weeks

Effective domaining is fundamental to geostatistical modelling for grade control. Through analysis of lithological, structural and alteration logging data, effective groupings (domains) can be identified and employed for estimation or simulation purposes.The poor definition of domains can adversely affect the grade control model resulting in a misinterpretation of the optimal ore-waste boundary and ultimately reduces the quality of recovered ore. The implementation of an appropriate domaining strategy is therefore expected to improve recovery and reconciliation.A thorough understanding of the geology of the deposit and adequate sample data is required for selecting domains. For new deposits, a resource drill database and resource model may be the only information available. Where extension to a previous operation is taking place, historic grade control, mapping and exposed geology may be used to improve domain selection. Preconceptions about domains, should they exist, need to be re-evaluated and tested to ensure they are fit for the purposes of grade control.While mining progresses, the domain model is re-evaluated to ensure that the previous interpretation is still suitable for the present configuration and geology. The grade control process, being iterative, lends itself to regular review and continuous improvement as further data is collected during the grade control cycle. Regular updates to the geology model, mapping, geostatistical data analysis and review of variography will provide indications of a changing domaining environment.Narrow vein gold deposits, which may have several factors influencing mineralisation, present considerable domaining challenges. By scrutinising the data, sample populations can be grouped into domains, which not only improve ore recovery, but help assist in the development of a mine geology model.CITATION:Matthews, G D, Haylett, M E, Weeks, A and Khosrowshahi, S, 2014. Effective domain selection for grade control in narrow vein gold deposits, in Proceedings Ninth International Mining Geology Conference 2014 , pp 191–196 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

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

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

Sep 1, 2014

By B Laidens, D Souza, W Bielefeldt

The CaO-MgO-SiO2-Al2O3 system, characterised by its intricate phases and thermodynamic properties, plays a pivotal role in steel secondary refining processes, encompassing desulfurisation, non-metallic inclusion capture, and refractory protection. Accurate predictions for diverse industrial applications, including metallurgy, ceramics, and materials science, are imperative. To address this challenge, a combination of machine learning techniques will be specifically applied to model the liquid fraction of the slag and the solid fraction of MgO. The development of an artificial intelligence (AI) system, leveraging various machine learning techniques, has gained momentum in this project. The focus of this work is on constructing an AI model, based on machine learning techniques, within the CaO-MgO-SiO2-Al2O3 system, utilising simulation results from FactSage™, version 8.1 (by GTT Technologies). The primary objective is to train the AI model using these simulation outputs to predict the percentage of liquid fraction and MgO saturation based on chemical composition parameters. The AI model will undergo training with a comprehensive data set of simulations within the CaOMgO- SiO2-Al2O3 system, covering a diverse range of compositional at 1873 K. These simulations, conducted through FactSage™ 8.1 software, provide a robust foundation for AI model training, ensuring generalisability and precise predictions for the liquid fraction of the slag and the solid fraction of MgO, the solid fraction of MgO in this case is determined by the difference between the total MgO and the MgO in the liquid fraction, so it is not the objective of this study to determine which phase of MgO is in the solid state.. The predictive capabilities of this AI model hold significant implications for process optimisation, quality control, and decision-making in CaO-MgO-SiO2-Al2O3- dependent industries. Precise estimations of the liquid fraction and MgO saturation empower researchers and engineers to enhance operational efficiency and quality. This paper explores the methodologies employed for AI model creation and training, achieved results in terms of prediction accuracy, and potential applications in the field. The development of this AI system signifies a notable advancement in utilising machine learning for better comprehension and control of complex chemical systems. Furthermore, to align the study with real-world steel production, we introduce FeO and MnO at concentrations of 2 per cent and 1 per cent at 1873 K, respectively, following the validation of model results using the CaO-MgO-SiO2-Al2O3 system. This adjustment aims to bring the study closer to the observed reality in steel mills globally.

Jun 19, 2024

By M E. Karmis

Traditional coal mining planning seldom considers key æsustainability factorsÆ such as: societal impacts in the area; jobs (both created and lost); dislocation of towns and residences; impact on neighbouring communities and individuals; infrastructure concerns; post-mining land use (except when limited by law or other factors); habitat disruption and reconstruction; long-term economic impacts in the community; and net long-term community benefit. This paper presents a systems engineering approach based on the premise that systems can only be optimised if all factors are considered at one time. In theory, coal mine designs can be optimised for return on investment, environmental protection and sustainability. Using this approach, the permitting process may be quicker and less costly, relationships with neighbours, communities, environmental groups may be improved, the mining industry may be seen as a positive for the short-term and long-term and the mining industry may increase profits. This paper discusses geographic information system (GIS) tools that may be used to incorporate ecological and other sustainable development concerns into models of coal mine sustainability performance. Along with coal production cost and value information obtained from past and present coal mining operations, GIS data are used to develop mathematical cost and equation models. By analysis of on-the-ground data, the parameters to be included in these models are identified, the relationships between these parameters quantified and the models developed. The paper also discusses the next phases of the work to be completed once the data is obtained and the models are adjusted and validated. At that time, site-specific information will be input into the models and the approach to mining a particular property evaluated and optimised for financial rate-of-return and other desired outcomes, such as preservation or enhancement of sustainability values. Finally, the paper will examine how this approach can be combined with traditional mining engineering considerations in order to develop an optimised mine plan for a specific mining property.

Jan 1, 2009

By T D. Jolly, L A. Balzan, A R. Harris, Z Bauk

"The availability of real-time data in any process control system is critical for effective management of that system. At MMG LXML Sepon Copper Operation in Lao PDR, controlling the copper grade of the feed to the leaching circuit is paramount for maximising both productivity and copper recovery. Since 2008, real-time analysis data has been available to the process engineers from the Geoscan on-belt analyser installed on the Copper Mill feed conveyor, and highly accurate results on copper grade have allowed the process engineers to strictly control blending to overcome the variability in plant feed grade. The availability of real-time analysis data is crucial, as effective sampling of this stream is both difficult and error-prone, being only a snapshot in time of highly variable ore stockpiles, as well as having significant laboratory turnaround delays. Periodic sampling is used to verify the Geoscan data as accurate. Since its installation, the copper result has been the most critical output of the Geoscan. In recent times, the process engineers have sought to utilise other results from the Geoscan to further improve and control the process. One measurement of particular interest involves the real-time measurement of calcium and magnesium as a gauge of ore feed gangue acid consumption. To satisfy this end, accurate measurement of calcium and magnesium is becoming increasingly more important and has been the subject of ongoing collaboration between Sepon and Scantech, the manufacturer of the Geoscan. This paper discusses this work, describing the calibration process and results obtained, while also providing a basis for Geoscan use in operations to enable enhanced process control for all potential Geoscan users.Citation:Balzan, L A, Jolly, T D, Harris, A R and Bauk, Z, 2016. Greater Use of Geoscan On-belt Analysis for Process Control at Sepon Copper Operation, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 231–238 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By J Rutter, D Francois-Bongarcon, M Federov, N Odiar, M Scott

There are two fundamental methods for metalliferous sensing of primary crushed ore available for deployment at operations. These methods can be classed as surface measurement techniques (including XRF, LIBS, NIR, SWIR) or penetrative/semi-penetrative measurement techniques (including PGNAA, PFTNA, GAA, MR). While the individual sensing technologies exploit different physical phenomena to measure metal content, penetrative sensor measurements of grade are often regarded to be superior to surface measurement techniques due to the much larger sampling volume penetrative techniques provide. Surface sensing techniques often utilise simpler, established technologies that have considerable benefits in the speed of analysis, capital costs, ease of deployment, social license to operate and operational safety. This paper investigates whether surface sensing techniques achieve adequate sampling representativity of primary crushed rock mass to provide economic benefit over penetrative sensing technologies for bulk ore sorting applications. The paper details the methodology used to assess whether surface XRF measurements change throughout various stages of comminution, and increased surface exposure, from primary crushed ore (top size of -175mm) to finely crushed product for assay (top size -2mm). The methodology was applied to 2 ore mineralisation styles, across variable metals and grades, to identify any associated opportunities and limitations to surface sensing techniques. The results assist in developing a method to determine if surface sensing and measuring via XRF is an adequate representation of the rock mass for bulk ore sorting applications and identify any associated limitations in particle size distribution, mineralisation or natural deportment strength to guide suitable application of surface sensing techniques.

Nov 10, 2020

By Z Gao, D Liao, W Sun, S G. Pooley, J Wang, Z Shi, G Jing, S Ren, Q Chen

Yuanjing processing plant is a scheelite and wolframite plant in southern China. Water shortages and recent environmental regulations mean that the plant must reuse the wastewater that comes from the mining operation. This paper describes the efforts to reuse the mining and ore washing wastewater (MOW) in the processing plant. Initial attempts to reuse the MOW in the strong magnetic separation were unsuccessful because the magnetic media pack was seriously fouled by the micro-fine precipitate generated. The focus changed to reuse the MOW in the scheelite flotation circuit, which includes one roughing, one cleaning and three scavenging steps. Laboratory batch tests showed this would likely be successful because using MOW reliably improved the flotation performance in the laboratory tests. Then a 20 day industrial trial was run in the plant. The trial was very successful with the enrichment ratio of WO3 increasing from 17.4 to 23.6, while the recovery remained around 79.2 per cent. The industrial trial was so successful the company immediately adopted the new scheme, which has remained in use ever since. This technical solution not only alleviated serious water shortages, and satisfied environmental regulations but also improved the plant performance.

Aug 24, 2022

By J Karlovšek

Civil engineering infrastructures are often subjected to different types of natural and mechanical activities. These influences may result in serviceability or even in stability of structures due to material deformations, increased water content within the materials used or the formation of internal or adjacent cavities that may threaten the infrastructure. Construction practices can lead to development of such defects in the form of cavities. In civil engineering it is crucial to detect these variations in material properties and to detect the presence of defects. However, as they are often hidden from view, these attributes may be difficult or impossible to target with traditional testing methods. For these reasons rapid geophysical methods, such as ground penetrating radar (GPR), are increasingly being used. At the University of Queensland (UQ) GPR is used for detection of voids and cavities which have been caused by an over excavation of the earth pressure balance machine (EPB) operating in a closed mode.A variety of numerical simulations using the finite-difference time-domain (FDTD) methods and preliminary experiments have been carried out in order to specify information about the nature, type, size, location and other characteristics of targets to be detected by GPR. In doing this the difficulty of interpreting GPR data, which is mainly due to the complexity of the factors involved in multiple possible solutions of the observed features, can be overcome.

Mar 8, 2011

By R Goater, P Kirsch, S Goater, I Goater

With staff productivity and retention a crucial factor in the longevity of AustraliaÆs mining industry, some mining companies are increasing their focus on the health and well-being of their people, to minimise the risks of deteriorating health in an ageing workforce. Many of AustraliaÆs mining operations rely heavily on long distance commuter (LDC) rosters, which are argued to have a significant impact upon worker health, wellbeing and lifestyle choices. The potential impact of workforce health on mine safety performance, efficiency and operating practice is an interesting additional line of enquiry. Food choice, exercise and recreation initiatives offer living and working conditions that æempower healthy choicesÆ in the shift worker community, but do not guarantee improved worker wellbeing. This paper explores first-hand the experiences of one individual over two and a half years of employment at different mine sites, under different shift conditions and across different operating crews. Novel insights and recommendations concerning the LDC lifestyle are offered through integrating reflections on one individualÆs fly-in, fly-out (FIFO) experiences in open pit mining operations from personal, family, professional and academic perspectives.CITATION:Goater, S, Goater, R, Goater, I and Kirsch, P, 2012. This life of mine - Personal reflections on the well-being of the contracted fly-in, fly-out workforce, in Proceedings Eighth Open Pit OperatorsÆ Conference , pp 31-40 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 18, 2012

By Y Zhou, Y Liu, J-P Yang, P Wang, K Hu

"Large-scale mine reclamation has taken place recently in response to the implementation of mining regulations in China. Effective monitoring of the progress of reclaimed land is a critical procedure to assess the quality of reclamation program and to ensure that mining enterprises fulfill their reclamation responsibilities. The present paper reports a preliminary study that examines the situation of mine land reclamation monitoring. Based on the monitoring, some general requirements for mined land reclamation have been proposed, including: the monitoring should be systematic and comprehensive the monitoring should be adapted to specific local conditions the monitoring should be reasonably optimised via scientific methods and technology the monitoring should stick to a variety of national technical criteria.The aim of land reclamation monitoring is to evaluate changes of critical indicators closely reflecting the development trend of the reclaimed mined land, to develop or improve the criteria and technical parameters specific to the site, and to prevent secondary environmental degradation. Based on these requirements and aim, the monitoring should cover the progress of reclamation, establishment of vegetation and plant community development; and recovery of land and water quality in the reclamation area. Regulatory measures are proposed which would improve the work of mine reclamation monitoring in terms of regulation, organisation and financial support.CITATION :Wang, P, Yang, J-P, Zhou, Y, Hu, K and Liu, Y, 2012. The primary framework for the mechanism of the mine reclamation monitoring in China, in Proceedings Life-of-Mine 2012, pp 47-50 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 10, 2012

By Y S. Zhang

Natural phenomena and human engineering construction activities had great influence on the geosciences space. Natural disasters, particularly mine disaster and other geological disasters happened frequently, which brought great losses both in people’s lives and economics, therefore, to explore the essential causes and mechanisms of disaster by some useful approaches is the most important step in mine disaster prevention. In a variety of methods, building an aground-underground seamlessly integrated model, and then analysing the formation and development mechanism of mining disaster based on this model is a useful way. In this paper, we studied an aground-underground seamlessly Integrated modelling method, and correspondingly given an aground-underground seamlessly integrated 3D spatial model, CSG+CD-TIN+GTP-TTS, by which we can carry out analysis of surface subsidence and underground laneway distortion efficiently, finally preliminary applications verified the effectiveness of this method.

Nov 22, 2011

By S Warden, T Neville, P Leckie

At its simplest, the classification and characterisation of an orebody is a matter of Where, What and When. Where and with what spatial resolution are measurements taken, What properties are measured, and When are the data acquired, processed, and delivered to create the most value. This paper delves into how existing and near-term advances in measurement technologies, field automation, and whole-system-digitisation are combining to open new routes for mine and exploration productivity improvement. Commencing when the initial exploration hole is dug, the advancement in deployment of survey technology—from expert-operated, to driller-operated, to driller-integrated—is used to demonstrate a template for adoption of higher technology measurements. We then introduce and discuss the multi-use measurement as offering outsized returns from a single measurement run, highlighting two new technologies that acquire rock strength while drilling and downhole assay data as examples. For rock strength, we highlight a novel approach to determining Uniaxial Compressive Strength (UCS) while drilling, its relationship to and advantages over Mechanical Specific Energy (MSE), and how it offers utility to multiple downstream processes. For downhole assay, we detail how a back-tophysics approach to Pulsed Fast and Thermal Neutron Activation (PFTNA) analysis offers significant advantages over other measurement methods and earlier implementations of PFTNA, generating a rich data set that can significantly extend and improve the information on which mining decisions are made. Finally, we discuss the possibilities enabled via optimising data delivery, collection, and curation— noting a fundamental limitation of historical systems and exploring the possibilities that will be unlocked by soon-to-market solutions that better enable Orebody Characterisation data to (virtually) move in space and time with rock material post-blasting. Ultimately, the value of optimising the Where, What, and When from point of measurement to the moment it generates maximum value will create greater life-of-asset production for a lower cost and energy input.

Sep 1, 2024

By PáDeáBosscher, A Bruwier, M Weidenbach, C Philippe, T Ly, A Van Den Bosch

In the mining business the cost of grinding media represents up to 40 per cent of the total milling cost and therefore grinding media optimisation has a direct impact on the concentratorsÆ bottom line. In the process of optimising grinding media alloys, Magotteaux developed its own methodology which consists of a series of analyses, tests, calculations and evaluations and assist the concentrator in optimising their processes.This paper presents the Prominent Hill case study where this methodology has been applied on both the secondary ball mill and regrind IsaMill«.The analysis of the wear conditions in the secondary ball mill allows Magotteaux to select a series of grinding media alloys to be tested to reduce grinding media consumption. By marking these different grinding media types with a unique drilling pattern, one can quantify the relative wear performance and cost effectiveness of each grinding media type within the same milling environment. After selecting the most economical grinding media composition a full scale industrial trial, involving topping up the selected grinding media is carried out and the media wear performance closely monitored and analysed.For stirred grinding mills, suppliers propose different grinding media, mainly ceramic beads, with specific properties and cost. Therefore the concentratorsÆ choice is a compromise between grinding efficiency, wear resistance and cost. The selection of the correct grinding media for stirred milling and the assessment procedure will be presented in this paper. The test results of the new stirred grinding media type in the regrind IsaMill« at Prominent Hill are presented and analysed.CITATION:Weidenbach, M, Van Den Bosch, A, Bruwier, A, Ly, T, De Bosscher, P and Philippe, C, 2012. Forging ahead - A collaboration between the OZ Minerals Prominent Hill Concentrator and Magotteaux to improve plant performance, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 105-110 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By C C. Souza, S C. Amarante, A C. Arauj

All major companies now producing iron ore in Brazil currently employ or are planning to employ some sort of concentration method to upgrade their fine sized products (sinter feed fines and pellet feed fines). The criteria for the selection of the most suitable concentration method for each application include a series of parameters; the most important among them being related to ore mineralogy. This paper reviews the concentration operations currently employed in Brazil and shows how ore mineralogy plays a fundamental role in the selection of a given method. Examples involving gravity concentration (jigs and spirals), magnetic separation (Rare Earth wet drums, ferrous wheel, and Jones type magnetic separators) and flotation (especially column flotation) are discussed. Fundamentally important for the selection of a concentration method is the mineralogy of iron-bearing minerals and gangue minerals presented to the feed to the concentration unit operation. For instance, the presence of liberated quartz as the major gangue mineral for a pellet feed size stream generally indicates that flotation will be the best selection for the concentration of that stream. However, even if magnetite is present only in the form of crystal relicts within hematite grains, it may lead to the selection of either magnetic separation alone or a combination of magnetic separation and flotation for concentrating such material. Presence of gibbsite and/or kaolinite as the major phase containing alumina will also affect the selection of the concentration method in all cases. Again for the case of pellet feed size streams, kaolinite does not interfere with flotation whereas gibbsite tends to contaminate flotation concentrate (pellet feed fines) as it is depressed together with iron oxides and hydroxides during the reverse cationic flotation process.

Jan 1, 2002

By L Lachance, F Flament, D Leroux, S Gariépy

The pervasiveness of poor sampling practices in and around mineral processing plants could seem intriguing in view of the various documented evidences both for causes and consequences. To this extent, this paper revisits the well-documented but lesser-known fact that failure to care sufficiently about how samples are selected and managed is the mother source of almost all sampling biases. The authors believe that the potentially huge leverage between causes and consequences as well as the diversity of people involved in sampling call for a globally integrated solution rather than for a point solution. Such a globally integrated solution has already been put forward by the AMIRA P754 Metal accounting – code of practice and guidelines (AMIRA, 2007) that inherently requires accuracy to be targeted, measured, reported and managed. Furthermore, always in order to avoid a point solution, several layers of protection against biases must be put in place with each one involving a different ownership whenever possible. This is exactly the role intended by the supervisory bias detection method described in this publication. It is based on the continuous monitoring of the expected value of reduced residuals obtained from statistical data reconciliation conducted in a metal accounting context. This supervisory bias detection method is developed in full details after which Monte Carlo simulations are done on a mineral processing plant example for showing how it can be successfully applied for detecting hidden biases.CITATION:Lachance, L, Leroux, D, Gariépy, S and Flament, F, 2014. Detecting sampling biases in metal accounting, in Proceedings Sampling 2014 , pp 109–120 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 29, 2014

By M Lee, J F. Carswell, G Reitsema

"The increased costs of underground mining have continually challenged engineers to identify opportunities for alternatives to common approaches to underground development. Considerations to the design of horizontal and vertical development at the Dugald River mine targeted inclined raise boring to reduce horizontal development, not only to reduce cost, but to allow development activities to focus on other areas of the mine.The mine plan consists of 50 raise bored ventilation shafts, of which 17 have been mined to date with diameters ranging from 3.1 m to 5 m and lengths from 30 m to 200 m. The expected performance and stability of these shafts has been determined using methodologies proposed by McCracken and Stacey (1989) and further refined by Peck, Coombes and Lee (2011). Actual raise performances have been collated and compared to a database of raise bore performances across Australia as presented by Coombes, Lee and Peck (2011), and form a database of raise bore performance specific to Dugald River.Opportunities to further optimise the mine plan and reduce costs have seen the introduction of large diameter-inclined raise bored ventilation shafts to minimise the required lateral development to connect the ventilation circuits. Large diameter inclined shafts ranging between 3.1 m and 4.5 m in diameter have been successfully mined with dips down to 70°, reducing the cost of lateral development by more than $1 million over the next two years.Both technical and operational challenges were overcome in the mining of large diameter-inclined raise bores, including modification of: existing methodologies of assessing shaft wall stability for inclined raises. These included variations of the McCracken and Stacey method and the utilisation of the modified stability number (N’) previously developed for stope performance (Potvin, 1988). both the collar and toe development profiles, including the general set-up of the raise bore drill rig to reduce the operational risks associated with angled raises.Due to their success, inclined raises have been designed for subsequent stages of the life-of-mine ventilation system at Dugald River. This has resulted in significant capital cost savings for the mine.CITATION:Carswell, J F, Reitsema, G and Lee, M, 2017. Vertical and inclined raise bore performance at Dugald River mine, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 313–320 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 16, 2017

By P B. Schwann

The commonly accepted genetic theories of Pilbara iron ores and Woodie Woodie manganese ores have often presented them as quite unique. This apparent uniqueness is not confined to just iron and manganese, but is also seen in gold and copper deposits in Western Australia. The published material on iron and manganese ores would seem to have either a quite complicated genesis or none at all. An alternate theory for the origin of these deposits is presented which involves a protore with simple oxidation and pH controls with hydrothermal fluid sources from the diagenesis and dewatering of the underlying strata. This theory explains the distribution, thinning, cold dolerites and very high concentrations of deleterious minerals observed in these deposits. This genesis system is also related to the systems that deposit hydrothermal gold and copper in sediments in the region.This paper presents the author’s observations, sampling and mapping after several decades studying and exploring for the minerals in Australia and locations overseas. All of these theories were developed with (or in spite of!) the guidance of Mal Kneeshaw, but would never have seen the light of day without him and the others presenting here. It is not what I would call scientifically polished, and possibly deserves more detailed studies; it is, however, presented as a discussion paper.CITATION:Schwann, P B, 2015. Related genesis for iron, manganese and gold-copper ores in Western Australia, in Proceedings Iron Ore 2015, pp 327–336 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By P F. Hodkiewicz, J de Lacey, M Stewart, R Lane

"Implicit modelling is an approach to spatial modelling in which the distribution of a target variable is described by a unique mathematical function that is derived directly from the underlying data and high-level parametric controls specified by the user. This modelling approach may be applied to discrete variables such as lithology (after converting the discrete codes to numeric values) or to continuous variables such as geochemical grades. This paper discusses the estimation of continuous (grade) variables using implicit modelling.One of the underlying engines of implicit modelling for producing this mathematical function description is the radial basis function (RBF). In essence, the RBF is a weighted sum of functions positioned on each data point. A system of linear equations is solved to derive weights and the coefficients of any underlying drift model coefficients. Once derived, the RBF may be solved for any unsampled point or averaged over any volume to provide an estimate of grade. It is possible, for example, to query the RBF on a regular grid to derive an estimate of block grades. Given the ease of creation of an RBF, and its ability to predict grade, the question arises as to how the grades derived from the solution of an RBF compare with grade estimates derived from conventional geostatistical interpolation methods (eg ordinary kriging (OK)).The purpose of this paper is to describe in lay terms: the basic structure of an RBF the role of parametric choice in the solution of RBFs and how this influences the character of the solution the fundamental similarities and differences between RBFs and conventional geostatistical estimators.Using a high-resolution conditional simulation, we show that in many situations RBF and OK estimates are very similar.CITATION:Stewart, M, de Lacey, J, Hodkiewicz, P F and Lane, R, 2014. Grade estimation from radial basis functions – how does it compare with conventional geostatistical estimation?, in Proceedings Ninth International Mining Geology Conference 2014 , pp 129–140 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 18, 2014

Australia as a leading producer of mineral sands has also occupied a leading position in many areas of research'in the processing and applications of these minerals. Research in upgrading ilmenite to produce synthetic rutile has resulted in the develop- ment of many processes, e.g,., Becher, Murso, Chlorine Technology, and ICI processes. Studies on the reducibility of ilmenites, aqueous leaching of reduced ilmenites, Fe-Ti-O system, leachability of natural and treated ilmenites in hydrochloric acid and selective chlorination of iron from ilmenites have been carried out in order to develop and improve the efficiency of the above processes. While research on the processing of zircon sand to produce high purity (99.99% ZrO2 zirconia powder and zirconium chemicals started only recently, research by CSIRO in the early 1970s led to the discovery of the phenomenon of transformation toughening in partially stabilized zirconia (PSZ) ceramics. Australia, with very significant resources of lanthanide-containing ores, pro- duces substantial quantities of monazite each year but research in processing and appli- cations of rare earths was neglected in recent years in this country. However, research to improve processes for the recovery of rare earths is now under way and studies on the production and testing of Nd-B-Fe magnets which are 1.5-2 times stronger than the strongest magnets (Sm-Co) currently available, have also commenced.' An overview of the research in the pro- cessing and applications of mineral sands during the last two decades in Australia and its implications for the industry are pre- sented in the paper.

Jan 1, 1986