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Boring of a 7.5Km long tunnel under the city of Stockholm commenced in January, 1987. The 3.5m diameter tunnel will pass under the buildings and as no ground settlement is allowed, the regulation for water leakage into the tunnel is very strict. Probe drilling will be carried out continuously ahead of the boring and when water is encountered the rock has to be grouted before passing with the TBM. The tunnelling system enables probe drilling to be carried out during boring with the TBM. This has earlier been a capacity reducing factor as the whole operation has been stopped during probe drilling. The project is using a new generation TBM especially developed for hard rock formations which require higher thrust per cutter to get a high penetration rate.

Jan 1, 1987

By Siemon J. R

It is possible to use compacted anodes formed at low pressure for the direct electrowinning of lead from sulphide concentrates. An anode containing 5.5 per cent graphite, formed into a compact at 34 MN m-2, enables lead to be won at a current efficiency of about 80 per cent; the power consumption .at 150 A m-2 current density being 0.4 kWh per kg lead. It would be necessary to use diaphragm cells to obtain a sufficiently pure product. A conceptual design for a full-scale plant is presented, together with a cost estimate for the production of lead by a process based on direct electrolysis of compacted concentrates. It is unlikely that the proposed process will be economically competitive with the conventional lead smelting.

Jan 1, 1976

By Ogilvie M

South Bulli is the oldest and largest underground coal mine in Australia. Two longwall units are in operation and current production is 2.5 to 3 million tonnes of run of mine product per year with a workforce of 600. Prior to 1984 a workforce of around 1,200 produced 1.5 million tonnes. Advances in technology can. of course, account for some of this gain, but the changes made in the human resources area are also seen as playing a major role in South Bulli emerging as a reasonably stable operation.The human resources strategy adopted recognises the value of the workforce and is aimed at not only fostering cooperation as all levels, but also making employees aware of the direct contribution they can make to the success of the enterprise.

Jan 1, 1991

By Clark G

The latest addition to the grinding circuit at Bougainville Copper Limited is another 5.5m by 7.3m primary mill (No.13). The mill can operate in a primary or secondary mode. Its distinguishing feature is its capability for speed variation, by means of a cycloconverter-fed synchronous ring motor. The engineering and metallurgical reasons for selecting such a drive system are described together with aspects of the installation and commissioning. Results of investigations into the relationship between mill speed and grinding efficiency are presented. It is concluded that mill speed variation within the range 70 to 80% of critical speed has very little effect on grinding performance. Beyond this range, grinding performance deteriorates. The same conclusions were reached when mill speed was varied at reduced ball charge levels.

Jan 1, 1986

By C Rizos

Many of the ‘new paradigms in mining’ and notions of ‘sustainable mining’ have at their core the requirement for reliable, continuous centimetre-level positioning accuracy to enable increased automation of mining operations. The deployment of precision systems for navigating, controlling and monitoring machinery such as drills, dozers, draglines and shovels with real time position information increase their operational efficiency, and reduce the need for humans to be exposed to hazardous conditions. The Global Positioning System (GPS) is the best known, and only currently fully operational, Global Navigation Satellite System (GNSS) providing positioning capability anywhere in the globe, on a continuous 24/7 basis, with accuracies ranging from the dekametre-level to the sub-centimetre-level depending on hardware and operational configuration. Despite this versatility, GNSS cannot satisfy the high accuracy positioning requirements for many applications in mine surveying, and mine machine guidance and control. The reason is that increasingly open cut mines are getting deeper, resulting in a reduction of the ‘sky-view’ necessary for GNSS systems to operate satisfactorily. Yet, to date there have been no viable alternatives to GNSS that can be deployed in mine environments that can meet the challenging requirements in open cut mines.Locata Corporation, a Canberra-based company, has invented a terrestrial high accuracy positioning system known as ‘Locata’ that can augment GNSS with extra terrestrial signals to permit cm-level positioning accuracy even when there are insufficient GNSS satellite signals for reliable positioning and navigation. Locata relies on a network of synchronised ground-based transceivers that transmit positioning signals that can be tracked by suitably equipped user receivers. Hence Locata can be considered a new type of ‘local constellation’, able to provide high accuracy positioning coverage where GNSS fails. This paper introduces some of the technical aspects of this Australian technology and describes tests conducted by Leica Geosystems over the last few years at Newmont Boddington Gold in Western Australia. A recent news announcement by Leica Geosystems (12 January 2011) has confirmed that their new mine management system will have combined GNSS + Locata positioning capability – the first commercial product that integrates GNSS and Locata capabilities into a single high accuracy and high availability navigation device for open cut mine machine automation applications.

Nov 22, 2011

By D Lucato, B Haase, R Saha, S Limberger-Forte, J Lishman

Cadia East Mining operations have employed geometallurgical techniques to advance the understanding of the in situ rock hardness variability across existing Panel Caves (PC). Geometallurgy advances the understanding of variability across an orebody through the integration of geology, mineralogy and processing response and therefore enhances spatial mapping of comminution or separation properties. Spatially extensive geometallurgical measurements are necessary so that continuous rock properties can be generated and used for the development of comminution and processing domains using geostatistical modelling. Standard testing protocol across geological and mineralogical domains is vital to understand the variability in deposit wide comminution and separation properties. The high cost and large sample requirements associated with metallurgical test work typically results in insufficient data density and distribution, making it difficult to model and map deposit scale variability. Quantitative hardness proxy tools are useful to measure in situ rock hardness, however this data is typically either sparse or missing within advanced mining operations. In recent years, mineralogy and multi-element assay data has often been collected as part of the standard geological data set and is generally coincident with metallurgical test work. In this paper relationships between mineralogy and comminution parameters have been applied to multi-element assay data with coincident measured Bond Work Index (BWi) data to generate a predicted BWi using linear regression. The predicted BWi is intended to supplement existing measured BWi data to enable better extrapolation across the deposit. Geostatistical Conditional Simulation methods have then used the predicted and measured BWi data to produce a BWi variable as a new input to the resource model. The simulated BWi can be used as an input for specific energy models to predict required grinding energy consumption across a deposit.

Mar 22, 2022

By B P. Wrench, M J. Gowan, P J. Chapman

Embankment dams constructed mainly of sand or non-plastic fine soils are susceptible to liquefaction, particularly in high-rainfall, high-seismicity environments where there is sufficient water to saturate the materials and sufficient energy from an earthquake to cause liquefaction. This paper shows the process adopted to review the stability of an existing cross-valley, centreline-raised cyclone tailings sand embankment dam.The study showed that two-dimensional stability analyses did not sufficiently capture the potential for instability, overestimating the depth of the critical failure surface. Instead, three-dimensional modelling was required to provide a reasonable representation. Post-liquefaction stability analyses carried out using the three-dimensional model indicated an adequate factor of safety (FoS). The FoS under seismic conditions was still considered to be a concern based on pseudostatic analyses (but noting the limitations of the analysis method).Earthquake-induced settlements were estimated using an empirical approach based on case history records (Swaisgood, 2003). The post-earthquake event settlement was estimated to be in the order of 600 mm, which is considered to be acceptable for the embankment, taking account of the proposed long-term freeboard of more than 8 m under operating conditions and 2 m under the probable maximum flood condition.CITATION:Chapman, P J, Wrench, B P and Gowan, M J, 2015. Review of static and seismic stability of a cross-valley sand tailings embankment in a high-rainfall, high-seismicity setting, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 163–172 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

By G Sartor, A Rich, D Grimsey, R Forzatti, M White

An in-depth process model was developed for the pyrometallurgical, off-gas systems and water balance of the Kalgoorlie Nickel Smelter. This model was used to assess plant capacity with changing concentrate grades, increased throughput and tighter environmental emissions under a range of potential future operating conditions. Comparison of modelled results allowed for flow sheet optimisation across a range of metrics including sustainability, processing capacity and costs. Process modelling software, METSIM® (ver 2020.06 by METSIM International), was used to simulate the flash furnace, integrated electric slag cleaning furnace, Pierce-Smith converters, matte granulation, waste heat boiler, hot gas handling equipment, wet gas cleaning plant and acid plant. The METSIM® model was divided into three separate, yet interconnected models: metals, off-gas and water balancing. This allowed for improved modelling efficiency and traceability while minimising manual error. The METSIM® model was supported by inputs from other specialised software. Chemical thermodynamics software, FactSage™ (ver 8.2 by GTT Technologies), was used to establish relationships for the flash furnace fluxing strategy and determine the operating temperature. Arena® (ver 16.0 by Rockwell Automation), a discrete event modelling software, was used to simulate material movements within the aisle as well as Pierce-Smith converter operation, allowing for integration with upstream and downstream systems. A dynamic data exchange (DDE) was used to connect the results of each software package, interfacing through Excel® (version 4203 by Microsoft). The integration between models provided a streamlined approach to test capacity, bottlenecks, water consumption and emissions under a range of operating conditions, enabling a more robust process. Further downstream modelling techniques were used to assess mechanical equipment. METSIM® outputs provided key parameters for combustion assessments using computational fluid dynamics and finite element analysis for the furnace mechanical design.

Aug 21, 2024

By C Jenkins, J Jasper, Y Suryaputradinata, S Lozyk, M J. Hartmann

The primary objective of mining companies is to function as a profitable business by delivering products that fit customer requirements in a safe and sustainable manner. Optimum resource utilisation is a critical focus area to achieve this objective, and the long-term sustainable business performance of a mining company is determined by the extent to which this is achieved. Technology improvements and/or new technology development could improve resource utilisation. However, adding new projects to a Brownfield operation carries risk. Overall project schedules, tie-in schedules and safety risks normally receive adequate attention, but the introduction and integration of new technology to a Brownfield site also carries the significant risk of failure to achieve design performance (quality or throughput). This risk must be addressed via rigorous design phase risk assessments and piloting. Post commissioning, the effective metallurgical integration of any new technology/circuit/process plant into an existing process plant calls for critical assessment, through circuit performance testing, and optimisation to ensure alignment with design criteria. In addition, this approach provides clear focus areas for further optimisation of the new plant and additional opportunity for overall plant optimisation. Roy Hill recently navigated this process successfully, and this paper provides feedback on the journey that led to improved resource utilisation.

Nov 8, 2021

By P Edmondson, S Narendranathan, S Setchell

The complexities of mining in current economic conditions, where ore extraction schedules are varied on a weekly basis so as to ensure constant supply to the process plant, can result in a number of scenarios that pose geotechnical challenges. This paper presents a case study where alterations in the mining schedule of a particular mine resulted in the necessity to mine under a large uncompacted embankment, ie integrated tailings and mine waste landform. To effectively ensure that ore recovery was maximised, a well-designed slope monitoring system to evaluate design performance and to provide timely warning of impending failures was imperative. In order for an appropriate slope monitoring strategy to be developed, a thorough understanding of the potential slope failure mechanisms, capabilities and limitations of available monitoring techniques is required. Communication of the monitoring results and response strategy to alarms generated by monitoring systems must also be carefully considered to maximise effectiveness. The results of preliminary stability modelling can be used to guide the design of a monitoring system, which in turn can then generate data which can be used to iteratively refine the geotechnical model. This paper illustrates the development and implementation of a slope monitoring system and associated communication system, using a case study developed at a large iron ore open pit mine in the Pilbara region of Western Australia.CITATION:Narendranathan, S, Lee, E C, Setchell, S and Edmondson, P, 2015. Modelling of an integrated waste storage facility, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 183–190 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

By E Gabriel, J C. Koppe, A Gomes and P Crispim, R Schaarsdmit, I Pablos

Drill and blast (D&B) is one of the most important production operations in open pit mining. The resulting fragmentation of the D&B reflects in the downstream unit operation. Good fragmentation of the ore will minimise the cost of loading, hauling and crushing. The understanding of the geological model integrated with a software system for bench face surveying and planning of blast layouts based on three-dimensional images can help to achieve the fragmentation goals of the mine operation. A case study integrating these tools was carried out in a large iron mine in Brazil. The iron ore in the study area consists of hard and friable itabirites. More than three different ore types may occur on the same bench. Under these conditions, data integration becomes necessary to improve the results of blasting. A blasting plan was based on the generated geological model. The methodology helps understanding the factors that can interfere in the fragmentation process, allowing defining actions that can improve the blast design in those places that fragmentation wasn’t achieved. This condition is important for a continuous improvement of the drilling and blasting operation. In comparison with the previous blasting carried out at Itabira mine, which did not take into account the geological model, substantial improvements in fragmentation were observed, eliminating the need for secondary blasting.CITATION:Schaarsdmit, R, Pablos, I, Koppe, J C, Gabriel, E, Gomes, A and Crispim, P, 2015. Geological modelling and bench face survey to improve blasting fragmentation, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 401–406 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By P N. Duan, Z G. Liu, M S. Chu, X X. Xue, B Liu, G J. Cheng, T Jiang, J X. Liu

High-chromium vanadium-titanium magnetite has not been exploited and made full use of on a large scale so far due to the immature utilisation technology and the reality that the utilisation efficiency of valuable metals still urgently needs to be improved. In the present paper, the isothermal reduction kinetics and mechanism of high-chromium vanadium-titanium pellets were studied at 800–1100°C. The mineral composition transformation of pellets before and after reduction was analysed by means of X-ray diffraction (XRD), and the microstructures were examined by scanning electron microscope (SEM) equipped with energy dispersive X-ray (EDX) to reveal the elemental distributions. The effect of reduction temperature on the volumetric swelling degree and cold crushing strength was also studied. It was found that reduction temperature has a large effect on the reduction rate of pellets, and the increase in reduction rate is more obvious in the range 1000–1100°C than 800–1000°C. The volumetric swelling degree of pellets increased with increasing reduction temperature, while the cold crushing strength decreased. The transformation of mineral species can be expressed as Fe2O3 ? Fe3O4 ? FeO ? Fe, Fe2O3·3TiO2 ? Fe3O4· (2FeO·TiO2 ) ? 2FeO· TiO2 ? FeO·TiO2, (Fe0.6Cr0.4)2O3 ? FeO· Cr2O3 ? Cr2O3 , and Fe2O3· VO/V2O3 ? VO. The apparent activation energy of the reduction reaction was calculated to be 44.3 kJ/mol, and the reduction rate is controlled by the combined effect of interfacial chemical reaction and gas diffusion through the porous product layer. The rate controlling steps were further studied by calculating the resistance percentages. The interfacial chemical reaction was found to be predominant in the initial reduction stage, with the percentage effect of gas diffusion through the porous product layer gradually increasing during reduction.CITATION:Cheng, G J, Xue, X X, Liu, J X, Liu, Z G, Chu, M S, Jiang, T, Liu, B and Duan, P N, 2015. Reduction kinetics and mechanism of pellets prepared from high-chromium vanadium-titanium magnetite concentrate, in Proceedings Iron Ore 2015, pp 349–358 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By T Soares, P Esteves, C Senna, V Souto, E Dias

Steinert provides a wide portfolio of Sensor Based Sorting (SBS) technologies, including the possibility to combine different sensor data in the development of the separation applications. This multi sensor approach provides a larger applicability and extensive flexibility for the technology. This effect is emphasized for mining applications, once every ore body presents its own features that can also comprise a large material variability. In this sense, every sorting application is customized and comprises a personalized solution. This means each project development includes a test work stage that approaches from the project discussion, test definition, up to test outcomes and processing development. In relation to very complex and large projects, a sorting pilot scale plant has become a crescent tendency. By having a pilot plant stage can represent a chance to test larger amounts of material from different mining areas, different mining projects, such as to consider different processing targets and application approaches. Based on that, a better understanding about the technology application can guide a more assertive development of large and complex ore sorting projects. The aim of this paper is to provide information about the applicability of the Steinert multi sensor technology at different pilot plants in South America. It consists in a compilation of laboratory test results, plant design and operational results. For that, a chromite, an IOCG deposit and a sulphide gold ore projects are presented. Additionally, the paper discusses the application of different sensor technologies combinations such as various processing targets, thus providing a wider understanding about sorting applications and flexibility.

Nov 10, 2020

By S N. Donaldson, B L. Hollis, K Wynn, L Potts, M Evans

A real-time load-haul-dump (LHD) dispatch optimisation tool has been deployed at Panel Cave 1 and Panel Cave 2 at Newcrest’s Cadia Valley Operations. The tool, known as ORB, is the first known successful implementation of an optimisation-based, autonomous, real-time dispatch tool, custombuilt for underground mining operations. ORB can co-ordinate the optimal dispatch of LHD’s in a block cave to achieve a range of objectives while adhering to draw compliance and geotechnical constraints. It is an example of highly automated short-term interval control. This paper starts by outlining the pre-existing business planning process, detailing the simple logic that produced the daily draw order. Next, the motivations for a real-time dispatch tool are presented, drawing comparison to the limitations in existing planning processes and how these can be overcome through an optimisation-based, autonomous, real-time dispatch tool. Subsequently, the paper details the Ratio Bogging Draw Strategy, through which tonnes targets are expressed continuously on draw bells or draw points as a ratio of total cumulative cave draw. This signifies artificial planning boundaries are removed and that draw targets are linked within a cave; such that tonnes are unlocked by bogging other parts of the cave, instead of as a function of time. This creates incentive within the target mechanism for fixing and bogging struggling draw areas whilst allowing uncapped progress if all draw targets are progressing within compliance. Furthermore, the optimisation tool developed is outlined, including the data it uses and the objectives it optimises. Finally, detail on the improvements to operations the implementation of this tool has brought, and the business process change it has facilitated are presented using Newcrest’s Cadia Valley Operations as a case study.

Mar 15, 2021

By P Craig, I Canbulat, J Naylor, J Emery, A Sykes

Longwall mining is by far the most common method of underground coal extraction in Australia. Industry trends and expectations are placing increasing emphasis on the reliability and productivity of these operations. Longwalls are becoming wider and longer while retreat rates are continuously increasing due to significant improvements achieved in longwall equipment reliability and automation. This increased longwall productivity is placing significant emphasis on the reliability of longwall panel development.Although there have been significant improvements in the reliability of continuous miners and hydraulic drill rigs, the traditional resin-encapsulated bolt installation is still the principal method used in all major coal producing countries around the world. Anglo American realised that an opportunity existed to introduce an alternative roof bolt installation technique called ‘spin-to-stall’ (STS) into Australia. STS was first introduced by Anglo American Coal in South Africa, where it has been successfully used for over a decade, though implementation of South African STS resin in Australia has proven to be near impossible. Therefore, a new STS development project was initiated between Anglo American Coal and Jennmar Australia. This paper summarises the journey of this project, the results achieved and the successful implementation of STS at Grasstree mine.CITATION:Emery, J, Canbulat, I, Craig, P, Naylor, J and Sykes, A, 2014. Development and implementation of spin-to-stall resin at Anglo American’s Australian Underground Coal Operations, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 287–294 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

The Callie Underground Gold Mine (Callie) is owned by Newmont Asia Pacific and located 531 km north-west of Alice Springs in the Northern Territory. Historically, stopes have been mined utilising a primary and secondary stoping sequence with cemented aggregate fill and rock fill respectively. Current and near-future mining will employ long hole open stoping with rib pillars and rock fill with a paste fill system approved to allow a higher extraction ratio from mid-2011. The Callie rock mass is of good quality with little or no mining difficulties during development and stoping to a depth of 1140 m below surface. Development is currently occurring at depth of 1360 m below surface. Stress damage previously observed only in secondary stope accesses is now observed in development unaffected by stoping stresses. A change in rock mass properties is being experienced with depth, with more pronounced and frequent joint planes. Also, other structures are intersected more commonly, such as lithological boundaries and fault zones. The 'Callie rock factory' mentality that has persisted for years is challenged. This paper covers an appraisal of the stress and ground condition changes at Callie. The appraisal outlines the mine design criterion that was developed and examines the transition from a low stress environment to one where stress damage is observed. Discussion includes a judgement on the rock mass damage observed in development, the dominant geotechnical factors influencing the change in ground conditions, and if a correlation can be made between the observed rock mass damage with stress through the use of numerical modelling.

Nov 25, 2010

By J Webb

The mining industry is relatively niche and complex compared to other global industries in its safety and operating environment. Whilst some of the technology required to decarbonise the mining industry will emerge from the mass market (eg batteries, energy storage solutions and renewable power generation) where exogeneous external investment and innovation will drive supply, bespoke applications such as material movement will be constrained by industry limitations. Underground load and haul equipment burns the majority portion of underground mine diesel, and typically 25 per cent of scope one and two emissions. Transitioning away from incumbent diesel engines offers a considerable health benefit to all mine workers, as well as decarbonisation achievements, and through trials there is emerging evidence of more productive equipment and realistic expectations of lower operating costs of fleet. However, new equipment and material movement systems that support these industry goals are currently approached with caution due to the pivotal role they play in delivering productivity goals, and the lack of experiential data and certainty to mitigate the supplier development risk during this technology transition period, where all resources are required to meet a booming industry. A group of mining companies and suppliers have the aligned aim to accelerate the understanding and availability of heavy haulage mobile equipment through collaboratively piloting equipment and working with suppliers and each other to aggregate market demand, encourage investment and resolve the mine design and technology choices through their involvement in the Electric Mine Consortium (EMC). This paper will outline the major challenges the industry must overcome in sourcing and adopting a zero-diesel particulate and zero-emission mine, drawn from cases and insights across ten EMC mining company members.

Mar 29, 2023

By B Murphy, T Mattsson, R Crosbie, T Maksimainen

"An Outotec e500 TankCell, with 500 m³ of actual flotation volume, was commissioned at the Kevitsa Cu-Ni-PGE concentrator in northern Finland during 2014. This flotation cell was implemented at the head of the existing copper circuit as the first Cu rougher flotation cell. This was the first flotation cell of this size to be run under production conditions by any supplier anywhere in the world.The cell has been in continuous operation since start-up in October 2014 and has provided improvements in metallurgical performance at very low specific power consumption. On average, the cell has recovered 71 per cent of copper contained in the 0.37 per cent Cu flotation feed at a concentrate grade of 17 per cent Cu. The specific power consumption for the cell (excluding blower power) is typically around 0.4 kW/m³.After start-up, the impeller speed and superficial gas velocity were varied and the impact on metallurgical performance measured. In this paper a review of the cell operation at Kevitsa is given. Furthermore, the impact of mixing and gas dispersion on metallurgical performance is presented.Citation:Crosbie, R, Mattsson, T, Murphy, B and Maksimainen, T, 2016. Metallurgical Performance of Outotec's e500 TankCell at the Kevitsa Cu-Ni-PGE Concentrator, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 127–134 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By P Willems, J B. Crow, R Dale

Open pit mining commenced at Lihir Island in 1997 and is undertaken using a conventional drill, blast, load, haul methodology. Unique challenges at the operation include an active geothermal system, a well-developed advanced argillic blanket in the upper portions of the orebody and high rainfall. Grade control is effective utilising routine blast cone sampling. While this provides ‘just in time’ grade information for mill blending, there are opportunities to improve scheduling of mill feed, based on material classification of clay types and sulfur grades. The nature of the clay can impact on the handling properties while the sulfur grade is an important guide for autoclave blending, required for refractory gold. Drilling below the pit floor introduces hazards from the identified geothermal field. A trial Reverse Circulation (RC) program was implemented with the aim of defining four benches below the active mining bench. A comprehensive risk analysis, including the geothermal environment, was undertaken to design a drill collaring procedure with pressure diversion equipment. Operator exposure was minimised through ‘nil on foot’ principles with the driller located in an onboard cab, utilising remote rod handling. Sampling personnel operate in an elevated platform with access to protective covering. Samples from blastholes and the RC holes are processed at two site laboratories. One provides conventional Au fire assays with additional Infrared Combustion (Leco style) S analysis. The second laboratory collects material classification details from portable XRF (pXRF), near infra-red spectrometry (ASD) and Hardness Indicator Testing (HIT). An existing workflow was updated by the site to deal with the additional samples and ensure production ‘turn around times’ were retained for short-term planning. This required some changes to drying temperatures, compositing and screen sizing for the material classification. All results from the two laboratories are loaded into a centralised acQuire database for estimation into a single block model that informs the 13 week medium term planning (MTP) schedule. This paper describes some of the logistical issues faced when drilling in a geothermal area. It also discusses the selection and commissioning Quality Assurance of the sampling equipment and drill rig. Integration of the resulting assay data with existing resource models is also explained.

Mar 22, 2022

By A Rantala, J Timperi and J Kaartinen, T Maksimainen, O Haavisto

"X-ray fluorescence (XRF) is the most common technique used for online slurry assaying in base metal flotation applications. Typically, assays from feed, concentrate and tailings slurries are used to monitor and control the flotation circuit, with possible additional sampling locations in other main slurry flows inside the circuit. The elemental content detection from the XRF spectrum is relatively straightforward as the spectrum contains element-specific peaks whose height corresponds to the element concentration in the sample. However, centralised XRF analysers measure the elemental concentrations line-by-line, which may increase the sampling interval for an individual line and cause unnecessary response delays, especially in large flotation plants. Reflectance spectroscopy is an emerging technique that can be used to obtain more frequent measurements from slurries. The measurement is based on the mineral-specific absorbance of light in the visible and near-infrared (VNIR) wavelength range. Due to this relatively inexpensive and simple measurement system, it is possible to conduct the measurement simultaneously in several slurry lines. However, the information contained in the VNIR spectra is more difficult to interpret as concentrations of all the minerals in the sample contribute to the measured spectrum and changes in solids content, particle size and mineralogy disturb the elemental content estimation. Therefore, frequent calibration of the measurement is required. This study presents the application of combined reflectance spectrum and XRF measurements for rapid online slurry assaying in a copper-nickel flotation plant. The XRF assays are utilised as calibration samples for the reflectance spectrum measurement, keeping the calibration model up-to-date. The rapid reflectance spectrum analysis is then used to provide an almost continuous estimate of the slurry contents, enabling further improved process monitoring and control.Citation:Haavisto, O, Maksimainen, T, Rantala, A, Timperi, J and Kaartinen, J, 2016. Reflectance Spectroscopy with X-ray Fluorescence for Rapid Online Assaying in a Copper-nickel Flotation Plant, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 85–92 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016