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By A Batnasan, K Haga, A Shibayama, K Higuchi, H Takeuchi

High silica (SiO2), alumina (Al2O3), and phosphorus (P) contents in iron ore adversely affect the quality of iron products. The removal of those impurities from iron ore is an essential point in further iron ore processing. In this paper, the removal of P, SiO2 and Al2O3 impurities from iron ore by alkaline drying followed by reverse cationic flotation is discussed. The reverse cationic flotation experiments are performed using the iron ore samples without and with alkaline drying pretreatment. All other flotation conditions except pulp pH (4–12) and particle size distributions (-45 to -250 μm) are held constant. A typical collector and frother, such as dodecylamine acetate (DAA) and methylisobutylcarbinol (MIBC), are used in the flotation experiments. Alkaline treatment is conducted before flotation using sodium hydroxide at fixed conditions. The impact of alkaline drying on the performance of iron ore flotation is evaluated based on the removal rates of P and SiO2 + Al2O3, iron grade, and iron recovery compared with the iron ore flotation without alkaline drying (direct flotation). X-ray diffraction (XRD) analysis indicates hematite and goethite are the main minerals in the iron ore, which assays 62.8 mass per cent Fe, 0.232 mass per cent P, 7.1 mass per cent SiO2 + Al2O3 (total) determined by X-ray fluorescence analysis (XRF). Results indicate that a combined approach is more effective for removing P and SiO2 + Al2O3 impurities from iron ore than the direct processing technique because the maximum removal rates of P and SiO2 + Al2O3 are 48.2 per cent and 66.5 per cent from the alkaline dried iron ore when 8.4 per cent and 13.1 per cent from the non-alkaline dried iron ore.

Sep 18, 2023

By G McCullough, J Bassan, d P. Knights, C T. Farrelly

By 2045, carbon-neutral mines will be economically producing products that are vital for the world’s transition to renewable energy. After overcoming significant technical challenges (and the investment of significant capital), leaders have successfully eliminated the use of diesel and other fossil fuels by introducing a wide range of new decarbonisation technologies. These leaders will be reaping the benefits of lower production costs (resulting from elimination of diesel), stable and predictable operations, and easier access to capital for their future projects. This paper describes a future scenario of how a net zero carbon and zero-entry mine could operate by taking maximum advantage of technologies in development or already proven in other industries. Some miners have been unsuccessful in their efforts to reach decarbonisation targets. Instead, they have been forced to close or offload their assets to be acquired by operators with better sustainability credentials, or, in some cases, to indigenous or community-based enterprises with vested interest in making operations viable and sustainable. Regardless of ownership structure, all successful mining operations will have fostered strong and positive community relations that bring education, health, security and economic development opportunities to the communities while respecting their traditions, land-uses and culture. As shallow, easy to mine deposits have become scarce, the majority of new mines are underground. Advancements in electric underground technology and the feasibility of ‘zero entry mining’ (with no personnel in active mining zones) has made it increasingly possible to economically operate underground mines, even at shallow depths. The newest mines have a near zero footprint on the surface, produce no harmful by-products, and are employing in-place or in situ methods of extraction that are efficient and low impact. Surface land-uses, such as agriculture and renewable energy generation, continue in the immediate vicinity of the mine, with no significant ground disturbance, community impact or environmental footprint.

Sep 1, 2024

By H Indirawati, R Ayres, A Nur Kasnanto, S Konopa

As a project moves through the mine life cycle, the quantity of data available increases and the understanding of the orebody matures. Incorporating new information quickly and efficiently in current 3D models, is essential for adding value across the life-of-mine value chain. At the Martabe Gold Mine, the resource development group manages 14 drill rigs on six resource projects, including three operating mines. The Martabe deposits are geologically complex and the volume of new information that becomes available each day is substantial. It is imperative that new geological and assay information is integrated into the 3D models as soon as possible, so that drill planning and targeting can be modified accordingly. Martabe uses Leapfrog<sup>®</sup> 3D software to update and interrogate the 3D models on a dynamic basis as data becomes available. This results in faster and more effective changes to drill planning and schedules. The impact of this is better drill productivity and cost savings due to optimal drill targeting, and availability of up-to-date models incorporating the most current data. CITATION: Konopa, S, Ayres, R, Nur Kasnanto, A and Indirawati, H, 2018. Optimised drill targeting using dynamic 3D modelling, Martabe Gold Mine, Indonesia, in Proceedings Complex Orebodies Conference 2018, pp 99–101 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By B Wentzinger

This paper presents the results of state parameter estimates in an active coal boiler ash storage facility using the most recent methods currently in use for cone penetrometer interpretation. State parameters estimates are also compared with the critical yield stress ratio approach, which is proposed as an additional liquefaction potential screening method. Recommendations are provided regarding additional in situ tests and laboratory tests that may be undertaken to improve the state parameter assessment and data produced for use in subsequent stability or liquefaction studies.

Jul 1, 2021

Problems caused by water discharge from surface mine ventilation shafts can be significant and are usually unforseen. The discharged water is often hyper-saline or acidic and can cause environmental degradation over a wide radius. It can also lead to recurring power pole fires and primary fan breakdowns. A range of solutions to the water discharge problem has been implemented in many Australian mines. In most cases the solutions have been ad hoc, with the overall cost and effectiveness varying tremendously. This paper reviews and contrasts the practicality and effectiveness of the various available remedial options.

Jan 1, 2002

By M Angus, S Konopa, A Virisheff, S Crispin

A positive mill reconciliation at a mine is a double-edged-sword. Much back slapping happens. The bank and the board can’t get enough until the downside becomes apparent. Over a prolonged period, there becomes an issue with market perception and the potential for shareholders to be misinformed regarding the potential value of the project. In addition, there are impacts on mine scheduling, waste allocation (or lack thereof), government expectations, and the potential for misguided external assumptions regarding the ‘unexpected’ results. The PT Agincourt Resources Martabe Gold Mine has shown a significant under-call, in the order of 20% total gold metal, between the Mineral Resource (MR) estimates and Grade Control (GC) estimates since production commenced in 2012. Recently, the under-call has been reduced by incorporating the use of grade control drilling in the MR grade estimates. Despite recent improvements in reconciliation, drilling in 2017 at both Purnama and Barani open pits shows that infill reverse circulation (RC) drill holes often produce significantly higher grades than those predicted in the MR block model. CITATION: Angus, M, Virisheff, A, Konopa, S and Crispin, S, 2018. Martabe Gold Mine, Indonesia: a positive solution for positive reconciliation, in Proceedings Complex Orebodies Conference 2018, pp 76–78 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By J Pearce, B Miles, V de San Miguel

Incorporating industry best practice waste rock management methods can be a relatively straight forward task when preparing management documentation, such as an acid and metalliferous drainage management plan (AMDMP). However, a key difficulty is the incorporation of industry best practice methods that are practical and non-compromising on their purpose from a scientific standpoint. The second key difficulty is the implementation of these practical methods as various operational groups/departments are typically relied upon to execute and take ownership of different tasks or procedures.One approach to overcoming these difficulties is to develop an AMD Operations Manual (AMDOM) that:•Incorporates, where practicable and without compromising scientific merit, existing processes that those groups/departments ultimately responsible for the execution of the management action are familiar with; and•Provides standalone, simplistic, and easy to follow procedures for site personnel. The purpose of the standalone operations manual is to ensure site personnel who are responsible for undertaking specific procedures, have clear, step-by-step instructions for an individual procedure, without requiring interpretation and understanding of the more comprehensive AMDMP.In adopting a best practice approach to waste rock management for their iron ore mine in Western Australia’s Pilbara region, Roy Hill developed an AMD Management System that is comprised of both an AMDMP and an AMDOM that are connected through adaptive management processes. The Roy Hill iron ore mine, which has a mine life of 18 years, will require the management of more than three billion tonnes of waste rock.CITATION:de San Miguel, V, Miles, B and Pearce, J, 2018. Practical waste rock management at the Roy Hill iron ore mine, Western Australia, in Proceedings Life-of-Mine 2018, pp 80–82 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By C Pope, M Tannock

Mining exploration and development projects in Australia are being negatively affected by the highly complex regulatory and bureaucratic processes at all levels of government. These processes affect mining companies operating in Australia by impacting on timelines and the cost of developing a mining project. It is not uncommon for the granting of project approvals to take in excess of five years, meaning that mining companies struggle with productivity, efficiency, time frame and cost issues in respect to their projects in Australia. As the mining boom in Australia is moving from the investment to the production phase, it is now more important than ever to maintain a regulatory landscape that facilitates rather than discourages new investment.While one of our key arguments is that there is too much burdensome regulation and red tape in Australia, we are also strongly believe that regulatory intervention is necessary to ensure that appropriate checks and balances are in place to serve the public interest and manage environmental, health and safety, social and other development-related impacts that may arise from a mining project. However, the regulatory intervention in Australia has come to a point where it is excessive and starting to discourage valuable investment in mining projects for nominal return to the public. Excessive regulation or ‘red tape’ impedes productivity and competitiveness, deters investment and innovation and costs jobs, all of which ultimately impact on the growth of Australia and the standard of living of all Australians.This paper aims to examine and compare the federal, state and local regulations that govern mining projects in Australia. It will highlight how these regulations are unnecessarily complex, lengthy and duplicated and how they can be streamlined to reduce red tape. In doing so, the paper will evaluate the recommendations proposed by the Productivity Commission Report on Major Project Assessments released in 2013, which include the recommendation to move to a ‘one project, one assessment, one decision’ regulatory model.CITATION:Pope, C and Tannock, M, 2015. Project development and regulation red tape – a comparative analysis: does it need to be so complex?, in Proceedings Iron Ore 2015, pp 621–630 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By X Hu, Z Pokrajcic, R Embry, P C. Stewart, J Carpenter, E Jones

Whilst the value of Pit to Plant and Mine to Mill optimisation has been proven since the 1990s, sustaining the productivity and efficiency gains typically requires ongoing test work, blast trials, plant surveys, and model calibration services. In contrast, the input to digital twin Pit to Plant or Mine to Mill optimisation is tens to hundreds of millions of tonnes of standard mine operating data. This paper presents a series of digital twin case studies from across the mine value chain, including machine learning testing methodology, model accuracy statistics and the application of Shapley Additive Explanations (SHAP) for model interpretation. These case studies demonstrate how machine learning and data fusion ore tracking connects hundreds of millions of tonnes of downstream performance data to produce digital twin models (operating models that are continuously updated and integrated into the wider Mine to Mill/Pit to Plant ore tracking system). Digital twin modelling software has been used to add block model variables for dig-rate, crusher and mill throughput, recovery (tailings grade), lump yield, product grade and product quality, fines yield and fines in lump. Block-by-block predictions are added to the geological resource and grade control block models as new block model variables. These new block model variables are used across all mine planning time horizons from life-of-mine planning to daily schedules. In addition to the materials handling and geometallurgical prediction case studies, the paper also presents digital twin case studies for drill and blast simulation and plant set point optimisation. The case studies show how digital twin simulation enables drill and blast engineers to simulate the effect of different blast designs in different blast domains using the mines operating data. Plant set point optimisation applies mathematical optimisation algorithms to the machine learning model to provide live operational decision support to metallurgists and plant operators. The digital twin machine learning case studies demonstrate a digital and sustainable paradigm for Mine to Mill and Pit to Plant optimisation.

Jun 22, 2022

By S Munn

Today, it can be said that the majority of mines utilise communications equipment in one form or another. Either for communications between staff making their day-to-day operations more efficient, or for emergency communications, as well as linking computer based mine management systems, and providing remote control over complex mobile and fixed machinery. With the advances in technology now available, we are moving into the next generation of mine communications equipment, using digital communications in the underground mine environment. It is a proven fact that an efficient underground mine communications system can help maximise production, by providing major gains in areas such as equipment and manpower utilisation, staff and vehicle tracking, reaction times to break downs and emergencies. In this paper we will describe some of the facilities that are currently available, as well as what will soon be available to mining and tunnelling companies around the world.

Jan 1, 1999

By J-P Franzidis, M Esvelt, E V. Manla

The Floatability Characterisation Test Rig (FCTR) is a self-contained, highly instrumented, mobile pilot plant that is able to treat up to 2 tph solids. It consists of a bank of six 130 L WEMCO« SmartCells« and a bank of six 50 L WEMCO« SmartCells«. It was developed as part of the AMIRA P9 Project, primarily to determine ore floatability characteristics and to develop and validate flotation plant modelling, scale-up and simulation methodologies. However, it may also be used to carry out pilot-scale flotation test work. This paper briefly describes the circuit modelling, simulation and scale-up test work performed using the FCTR and the use of the FCTR in pilot-plant test work performed by the metallurgical staff at WMCÆs Kambalda Nickel Operations and Mount Keith Nickel Operation. At both Kambalda and Mount Keith the FCTR was found to be very flexible and straightforward to run, with an easily changeable circuit configuration and stable operation. Testwork was facilitated through having full stream sampling on all streams, and a high degree of instrumentation providing accurate measurement of process variables. The results obtained from the FCTR testwork were highly repeatable. As a consequence of using the FCTR, WMCÆs Kambalda Operation and Mt Keith Operation were able to complete a rigorous programme of pilot plant testwork more quickly than in the past, and with a high degree of confidence in the results.

Jan 1, 2003

By S Mitra, B J. Monaghan, T Honeyands, G Evans, R Chowdhury, D Scimone

Due to the harsh operating conditions, wearing of the inner refractory lining in a Basic Oxygen Steelmaking (BOS) furnace reduces the useful life of the refractories and incurs a significant cost component for relining. In this study, firstly, a combined compressible and incompressible computational fluid dynamics (CFD) model was developed to identify the potential wear prone zones in an industrial scale BOS system during the supersonic oxygen blowing phase by quantifying the wall shear stress distributions. Next, the retained slag splashing process was simulated by introducing an inert gas to residual slag mass to achieve a protective coating on the refractory walls. Effect of both design and operational parameters such as lance head configuration, lance position and the initial slag volume on the slag wall coating performance were quantified and most favourable conditions were determined.

Jun 19, 2024

By S Khadhraoui, T Yusuf, C Kirmse, E Hecker, R Degel, A Akouch, N Borowski, M Reuter

For an optimal design and control of metallurgical processes, a deep understanding of the thermodynamics of the governing reactions is required. Modelling the thermochemical behaviour of those reactions is complex, as it involves multi-component and multi-phase systems. For this purpose, thermodynamic computing systems such as FactSage™ (Bale et al, 2016), which combine Gibbs energy minimisation routines with large databases of optimised thermodynamic data of solutions and compounds, have been used within the SMS group GmbH. Recently, the successful integration of those thermodynamic computing systems into the digital platforms of SMS has been achieved through ChemApp, which made running complex thermochemical calculations in Python-integrated development environments possible. ChemApp is a programmer’s package for thermochemistry and incorporates the Gibbs energy minimiser of FactSage™ as reported by Petersen and Hack (2007) as well as by Zietsman and Petersen (2018). The digital platforms link the fundamental and the industrial aspects together and can be applied as a process advisor, or for the evaluation of the environmental footprint and the economic implications of different process routes, as discussed by Reuter (2023). Two examples illustrating the progress of the developments in this regard will be introduced: 1. The Tilting Refining Furnace (TRF) for copper scrap recycling and refining to anode copper (the BlueControlApp). 2. Dephosphorisation control for the oxygen steelmaking process (Basic Oxygen Furnace (BOF)).

Jun 19, 2024

By J Herrmann, J Richards, B Hutchison

An extensive trial of laser-based survey and monitoring systems at Hillgrove Resources Kanmantoo Copper Mine in the Adelaide Hills, South Australia, has proved the capabilities of the system in monitoring rock movements on open pit walls. Initially, the trial involved deploying a Maptek I-Site 8820 laser scanner and the proof-of-concept Maptek Sentry software in the Nugent Pit to monitor ductile rock movements located up to 260 m away. The system was proven to be capable of monitoring various rock movements from 1.5 tonne rockfalls up to a 40 m high toppling wall failure. Data collected from smaller rockfalls was used to help build a database for Hillgrove’s rockfall management program. As part of the trial, the laser scanner was deployed to monitor a ramp movement event, as well as the toppling failure, adjacent to an IBIS slope stability radar. Both devices monitored the slump and the slowly developing toppling movements, with similar results. Although the radar was used as the successful ‘critical alarm’ device for the toppling failure, post-failure analysis showed the laser-based system to be capable of performing a similar role in the ductile rock regime; albeit over much shorter distances than the radar capability. A second laser scanner was deployed to monitor Kanmantoo’s Emily Pit in early December 2014, where it successfully provided critical alarm warnings for a block topple event. Sentry software, which takes advantage of Maptek I-Site 3D spatial imaging technology, was first released in November 2014 to meet industry demand for a cost effective, flexible system to detect movement. Sentry has now been re-launched as a fully transportable monitoring system. Deployed in a custom trailer, the system offers a power and communications module, cellular and Wi-Fi networking and a stable bollard for the I-Site laser scanner and Sentry software. This paper will present rock wall movement data from the Sentry trial and a subsequent two years of monitoring of the open pit walls at the Kanmantoo Copper Mine, at distances out to 750m. In addition, examples of remote geological mapping and small rockfall detection, using the laser scans, will be described. The Sentry system has proven to be beneficial for the continual improvement of slope monitoring and risk management at hard rock mines. CITATION:Hutchison, B, Richards, J, Richards, J and Herrmann, J, 2018. Mine rockfall and rock wall failures – proven digital laser-based approach for monitoring slopes at the Kanmantoo Copper Mine, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 463–472 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By S Khosrowshahi, A Weeks, W J. Shaw

"To provide an indication of expected performance of the mine and mill, feasibility studies should include an assessment of the expected day-to-day variability in process plant feed. Attempts to do this based on conventional resource models will be flawed as such studies fail to consider and account for the in-built smoothing (averaging) of input data.This can lead to one of two situations: an expensive, over-engineered process plant that can cope with every possible situation, or operational strategies that fail to manage the natural variability within the orebody and the impact of day-to-day operational decision-making.In both cases the value of the project diminishes through excessive capital costs or reduced throughput or recovery during operations.Unlike conventional estimation techniques, the geostatistical method of conditional simulation can reproduce the inherent variability of the deposit. Once a valid model has been developed, it is possible to analyse the model using a transfer function that simulates the proposed mining processes and provides a representation of the likely variation of mill feed characteristics at any time scale.The case study demonstrates how the proposed mining strategy would result in mill feed being considerably more variable than expected, resulting in poor recovery, low throughput and potential breaches of environmental conditions. Mitigation measures included budgeting for additional mining equipment to enable greater flexibility during mining and revised stockpiling and crusher feed strategies.Awareness of the benefits of modelling the variability of geometallurgical parameters will increase the use of this approach in producing more realistic financial models of expected mine performance at the design stage.CITATION:Shaw, W J, Khosrowshahi, S and Weeks, A, 2013. Modelling geometallurgical variability - a case study in managing risk, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013, pp 247-252 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 29, 2013

By L H. G McClean

Environmental, social and governance (ESG) factors have always been important to the minerals industry and is now considered one of our most important opportunities (and risks). Getting it right from the beginning is critical for the minerals industry, and that starts with mineral exploration. Exploration, or the process of investigation of an economic mineral deposit, is generally low impact and short-term. Exploration operations vary in size and scale and often shift priority, focus and location relatively quickly. Australia is a highly regulated jurisdiction with different regulatory systems and requirements in every state and territory. Most mineral exploration is undertaken by junior exploration companies or ‘explorers’. Exploration companies are lean operations with limited staffing and resources, traditionally with no income apart from funds raised or work through partnerships. Funds are tight and administrative investment is minimised so that investment into activity on the ground is maximised. All these variables mean that understanding and implementation of ESG frameworks for an exploration company can be challenging. ESG is a fast-moving sector with currently multiple frameworks and reporting standards. Interest from community and government stakeholders as well as investors and off-take partners has been growing, with mandatory reporting soon to be implemented. The upcoming changes to the JORC Code will ensure that ESG considerations will be a key component of all public reporting. Resources have been developed to support explorers implement, manage and report on ESG considerations. Due to their scale, agility and direct importance of land access and social licence, many explorers are not the ‘cowboys’ (or ‘cowpersons’) of the industry, but industry leaders in ESG. Strong interest and leadership have led to innovative practices and strongly embedded vertical frameworks that directly contribute to social licence to operate.

Sep 1, 2024

By B McCarthy

Mining has been typified of late as a boom and bust, cyclical industry operating against a steady decline in the size and quality of mineral deposits. Decreasing deposit grades and increasing costs of traditional mining techniques, all in the face of another commodity downturn, are forcing mining companies more than ever before to seek out new and innovative ways to operate. New technologies are emerging to model, control and track resources through the mining value chain, to move material about mines more efficiently, and to identify and separate ore from gangue early in the extraction process.Discovering such technologies however is only the first challenge for mining companies. Actually implementing technological change successfully has proved to be an even bigger challenge. Like for many industries, fulfilling the promised benefits for the expense and timing envisioned, has not been easy when innovative technologies are introduced.Citing the author’s insights and experiences in a number of emerging technologies, this paper explores barriers to implementing technological change in the mining context. Key elements of a change management framework, first developed for implementing mine management systems, are described to give mining executives insight into how they and their organisations can succeed through technology-driven change.CITATION:McCarthy, B, 2016. Successfully implementing technology-driven change in the mining environment, in Proceedings International Mine Management Conference, pp 89-104 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 22, 2016

By E Widzyk-Capehart, P Vallejos, R Asenjo, J Ruiz-del-Solar

Throughout the minerals industry, it is evident that a new wave of technological innovation is needed as the mining sector looks for ways to achieve higher security and safety as well as higher production rates with less investment. Innovation has always been one of the key factors in achieving success within the mining industry. However, its importance will be especially relevant in the coming years if negative trends in commodity prices and new challenges facing the industry (lower grades, deeper mines and economy of scales) are to be overcome and the future sustainability and profitability of the sector ensured.The drive towards fully autonomous operations has begun, with the implementation of automated systems in both surface and underground operations. However, these automated systems are currently planned and realised with well-defined automated tasks within structured environments and isolated spaces. Currently, there is no interaction between automated systems, manned systems or humans, which creates physically isolated environments.For fully autonomous and continuous operations, the automated systems need to operate in environments that enable flexible interactions between automated machines, tele- and manually operated machines and humans.In this paper, we address the automation paradigm considering the synergistic collaboration between humans and automated systems. In this paradigm, humans and machines would interact in a flexible, collaborative and synergistic way without the need for isolation. The implementation of this concept within mining operations will have to be underpinned by science and technological developments and will require adaptation from many fields, including robotics, automation, distributed systems, communication, human factors, pattern recognition and mine design.The paper also presents the research and development work being undertaken at the University of Chile’s Advanced Mining Technology Center, in collaboration with the Chilean mining industry. This will provide the basis for flexible interactions between humans and technology-based systems towards a future of autonomous and continuous mining systems.CITATION:Ruiz-del-Solar, J, Widzyk-Capehart, E, Vallejos, P and Asenjo, R, 2015. Synergistic collaboration of humans and automated systems – innovative steps towards fully autonomous and continuous mining systems, in Proceedings Third International Future Mining Conference, pp 83–94 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

By A Boucher, M Baudin, P Androszczuk, I Minniakhmetov, A Rigby, P Machado, M Wright, B Van Dijken

IGO Ltd’s (IGO’s) Nova Operation (Nova), which is 160 km east-north-east of the town of Norseman in Western Australia (WA), mines and processes nickel-copper-cobalt (Ni-Cu-Co) sulfide ore from the magmatic Nova-Bollinger Deposit (Nova-Bollinger), which is hosted by the Mesoproterozoic age high-grade metamorphic rocks of the Albany Fraser Orogen. Over its 56-month life-of-mine (LOM) operations to 31 December 2020, Nova has processed 5.63 Mt of ore grading 2.04 per cent Ni, 0.86 per cent Cu and 0.07 per cent Co from its underground mine. At the end of 2020, both the Nova-Bollinger JORC Code reportable Mineral Resource estimate (MRE) and Ore Reserve estimate (ORE) were >90 per cent classified in the highest JORC Code confidence categories of Measured Mineral Resource and Proved Ore Reserve respectively. The high JORC Code classification confidences assigned to the Nova-Bollinger MRE and ORE results from the 386 km of surface and underground diamond drill testing of the deposit to a nominal 12.5 by 12.5 m pierce point spacing in mineralisation. The close spaced high-quality drilling and bulk mining method employed at Nova has effectively removed the need for any grade control modelling outside of the MRE process. Importantly, having only the one fully drilled out deposit being mined and only the one process plant, Nova’s reconciliation process is in the fortunate situation of not being confounded by issues such as external ore sources and constant updates as new grade control information becomes available. IGO’s Nova reconciliation processes are focused on reconciliation ratios that quantify operational period differences between the MRE and ORE head grade and tonnage forecasts and the process plant head actuals. These metrics have been used to identify key reconciliation issues and have initiated several studies into the causes for specific reconciliation results, which are discussed in the paper. In late 2020, a period of sustained poor reconciliation results led to the recognition that increasing the understanding of risk between the MRE and ORE should be investigated. To assist with modelling stope level risk within the mine plan and subsequent reconciliation, an attempt was made to develop a formula to quantify ‘stope risk’ from MRE metrics such as sample spacing, kriging efficiency and so on

Mar 22, 2022

By G Hill, D Grant, M Tyler

Located approximately 570km NNW of Adelaide in South Australia, the Olympic Dam mine (OD) is the world’s fourth largest remaining copper and gold resource and the largest uranium resource. Discovered in 1975 and going into production in 1988, the operation consists of a fully vertically integrated underground mine, mineral processing plant, copper smelter and refinery, as well as associated infrastructure. BHP achieved production of 203,000 tonnes of copper cathode plus associated by-products in financial year 2016. The immense size and high-grades of the Olympic Dam resource offer a range of growth pathways, making closure timing estimation and planning a challenge. Current estimates put the OD resource at approximately 79 million tonnes of copper. Major factors influencing the closure timing estimation, as a result of the large resource and grade tonnage profile, include the mining method that may be used and the downstream processing method, ultimately influencing such things as the total disturbance area and the extent of infrastructure to be demolished at the end of mine life. In addition, factors such as the mining and processing method and production rate have a direct impact on larger rehabilitation items such as the total number of tailings cells required.CITATION:Grant, D, Tyler, M and Hill, G, 2018. Olympic Dam mine closure planning process, in Proceedings Life-of-Mine 2018, pp 43–45 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018