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By P Clark

This paper discusses the challenges, solutions and lessons learnt as tunnelling work continues on the Melbourne Main Sewer Replacement (MMSR) project.The MMSR project is a $220 million dollar project for the Melbourne Water Corporation. It involves the construction of approximately 4.2 km of new sewer from the southern fringe of the CBD through the inner metropolitan suburbs of Port Melbourne and South Melbourne.Of the 4.2 km of sewer currently in construction approximately 2.2 km will be constructed using a 2.95 m diameter Lovat EPB tunnel boring machine (TBM) with approximately 1.9 km of small diameter (300 to 600 mm) reticulation sewers constructed using trenchless techniques.These sewers are being constructed in a dense urban environment, which means that the tunnels and shafts are often in close proximity to buildings and structures. The underground constructionof the sewer is further complicated by the variable geology of the ancient Yarra River delta which includes weathered basalts, the infamous Coode island silt formation and fine loose sands.Some of the key challenges and lessons learnt so far during construction include:· steering and alignment control of the TBM through very soft silt with little residual strength,· development and refinement of a monitoring and alarm system for leaving the machine dormant on a day works only project,· control and measurement of tunnel lining defl ection during ring build and grouting,· prediction and monitoring of surface settlements during tunnel excavation,· improved understanding of the geology and hydrogeology at this previously unchartered area of Melbourne,· consolidation settlement due to dewatering at shafts required careful construction controls, and· ground support and excavation in close proximity to the existing 110 year old sewer which requiredvery detailed risk control measures.

Mar 8, 2011

By H Bruyn, K Ehrig, V Liebezeit, A Robertson, M Smith, D Grant

"The Olympic Dam geometallurgy program has generated a large quantity of data that has been used to create a geometallurgically enabled block model. An ongoing challenge is to convert data into usable information and embed geometallurgical practices into resource model development and mine planning to assist with the identification of opportunities to maximise value.This paper will discuss the methods used to disseminate geometallurgical information throughout the planning life cycle including data extraction methods from the geometallurgy acQuire database, and the inclusion of a geometallurgy module in the Olympic Dam Stope Reserves database. The use of geometallurgical information in short-, medium- and long-term mine design and scheduling, including its use in grade descriptor development and stope value assessment tools will also be presented. The detail of development of specific geometallurgical models is outside the scope of this paper.At Olympic Dam, the incorporation of geometallurgical capability within the long-term planning team, traditionally the domain of mining engineers, has proved essential in broadening the base of geometallurgical knowledge as well as focusing geometallurgy resources on value-adding areas while providing a holistic risk based long-term plan.CITATION:Liebezeit, V, Ehrig, K, Robertson, A, Grant, D, Smith, M and Bruyn, H, 2016. Embedding Geometallurgy into Mine Planning Practices – Practical Examples at Olympic Dam, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 135–144 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By Will D

This presentation is to outline the current practice of mechanised stoping a one-metre wide, gold bearing ore body to optimise fragmentation, minimise dilution and reduce stoping costs.Coolgardie underground operations have historically been mined using traditional shrink stope methods, but in this recent economic environment (with falling gold prices and high costs of traditional methods) it was necessary to look for alternative methods in order to reduce costs and increase productivity.Although still in a learning and refinement phase, CGNL is satisfied that it is feasible, practical and more economic to use mechanised long up-hole stope and long-hole rising methods to significantly reduce the mining cost, reduce dilution, increase safety and increase productivity three-fold compared to traditional airleg methods used throughout the Fasten Goldfields.

Jan 1, 1993

By J Tibbett, A Colebourn, B Hebblewhite, F Suorineni

The concept of Big Data refers to data sets that are so large, variable and/or complex that traditional data processing applications struggle to integrate the data for effective investigation, analysis and value generation. With advances in sensor technology and smarter equipment, the mining industry is experiencing Big Data, and in a different way to how the intelligence and marketing communities experience Big Data. Future mining will bring larger, more complicated and diverse data sets increasing the strain on traditional data integration and investigation techniques. Block caving is an important mining method for the extraction of massive, low-grade ore deposits due to its low operating cost and high production potential, given the right orebody geometry and ground conditions. This paper focuses on block caving due to its increasing popularity and importance in the future economic extraction of multiple commodities. The block cave mining system (BCMS) is a complex interrelation of factors, and due to the reliance on natural processes within the system, it is one of the least understood mining methods. Obtaining information on the factors within the BCMS generates large, complex data sets on various time scales. Each sensor network within the BCMS combines spatial and temporal information with tens to hundreds of recorded parameters. Data sets are quickly moving from multidimensional to n-dimensional. Optimisation of the BCMS is only possible through a holistic analysis approach, thus involving the integration of multiple, diverse, n-dimensional data sets (Big Data). This paper presents a current example BCMS Big Data situation involving 12 sources of information with differences in volume, data format and frequency of data generation. This suitability of virtual reality scientific visualisation (VRSV) as a solution to BCMS Big Data interpretation difficulties is then discussed. These 12 data sets can be effectively integrated using VRSV for intuitive and accelerated investigation of the BCMS. Potential future Big Data within the BCMS is presented involving 20 sources of information resulting from our increased need for monitoring and advancements in technology. Current methods of defining queries may not be suitable within these future complex, multidimensional data sets, and the potential of artificial intelligence algorithms within this system is discussed. These advancements in technology and machine learning lead to the requirement of live data acquisition and analysis. VRSV is identified as a suitable technology to satisfy the needs of real-time insight into the performance of these future caves for optimised management and reduced risk.CITATION:Tibbett, J, Suorineni, F, Hebblewhite, B and Colebourn, A, 2015. Virtual reality scientific visualisation – a solution for big data analysis of the block cave mining system, in Proceedings Third International Future Mining Conference, pp 109–116 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

By J Bohm, B Csoke, I Tarjan

In process technology, especially in coal preparation, it is often necessary to have a continuous knowledge of the average density of granular material in order to achieve both quality control and process control. The paper presents a new method and means supported by laboratory measurements for the rapid, practically continuous, determination of the average density of continuously supplied granular material through frequent sampling.

Jan 1, 1993

By J P. Sykes, T C. McCuaig, J E. Vann

Resources added to the global metal inventory through exploration over the past 15 years have been generally of poor quality (declining grades, recoveries and lack of acceptable financial return). Similarly, companies opting for an acquisitions-based strategy have had to pick from a group of poorer quality resources left from previous exploration booms, and will struggle to deliver this metal to market economically. Increasing difficulty in obtaining sufficient social and community acceptance of mining projects and potentially an energy-constrained future may exacerbate this problem, redefining what is considered ‘ore’. There will need to be more focus on deposit quality, defined as sustainable margin in the future business environment.Traditionally there has been a lack of translation of ‘mineralisation quality’ back to mineral project design and mineral exploration. This disconnect is due to two main factors: the first is technical – inherent deposit variability; and the second is organisational and socio-psychological –the mindset of explorers and project managers themselves.There are four elements to value realisation for a mineral deposit: (1) social licence to operate; (2) geological factors (depth, geometry, water and geotechnical, and geometallurgy – influenced by texture, mineralogy, chemistry and grades); (3) financial engineering (capex, opex, future commodity prices, future energy prices), and (4) operating factors (production rate, recovery, energy consumption). These elements are strongly interdependent, and geology underpins and drives linkages between them. A quality deposit addresses all of these elements and thus can be developed in a time frame that allows acceptable returns to the owners of the invested capital.Geological drivers of the above elements can be measured and mapped throughout a deposit. Moreover, when viewed in the context of mineral systems, a predictive understanding of the common causative processes of quality (despite deposit-scale variability) is emerging, and with it the ability to target quality of mineralisation, not just quantity of mineralisation.The second factor is a ‘heuristic software problem’. Current lines of education (and consequently organisational and professional structures) are discipline-based, producing ‘silos’ that do not speak each other’s language and work with different ‘mental models’. People who effectively recognise systemic links between these silos are called ‘boundary spanners’, of which we propose two distinct types: outside-insiders and inside-outsiders. Outside-insiders are people who are within a community, but recognise advances in outside fields and effectively integrate them into the community. Inside-outsiders start outside of a community, and successfully bring new ideas into it. Common traits in boundary spanners are: they seek exposure to (and embrace) key ideas that are outside of the framework of their own specialisation; they have high mental processing ability (MPA) – the ability to connect systems that are currently not perceived to be connected; and they introduce ideas from outside a field into a new context in a way that re-frames the field.The challenge is to identify and nurture potential boundary spanners that can build critical links, in particular between the (largely geoscientific) mineral exploration mindset and the (largely non-geoscientific) project development mindset. Critical linkages to be built are between mineral system science, targeting science, and whole of value chain modelling.CITATION:McCuaig, T C, Vann, J E and Sykes, J P, 2014. Mines versus mineralisation – deposit quality, mineral exploration strategy and the role of ‘boundary spanners’, in Proceedings Ninth International Mining Geology Conference 2014 , pp 33–42 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By R Thompson, D Tulloch

"Wet-weather or 24×7 wet-trafficability is a commendable design objective for unpaved mine haul roads, but practically often difficult to achieve, due both to the road sheeting material selected, and also its breakdown under the action of traffic and environment. Accidents allied to wet-trafficability issues, either due to rain or often more commonly, over-watering of mine roads, is increasing and especially the loss of control or uncontrolled vehicle movements categorisation. The dominant system failure is that once vehicle control is lost, control cannot be regained.The friction supply, or ‘skid resistance’ of a mine haul road sheeting is critical to the safe operation of the road and data has to be collated concerning the variation of friction supply with sheeting material engineering or indicator properties. In the light of the paucity of data existing in this field, this paper presents the contributory research that informs the development of improved and validated unpaved mine road friction supply estimates, based on a number of mine site evaluations across a range of sheeting material types and characteristic parameters, leading to improved predictive models of friction supply.Results from this preliminary review will enable operators to assess their road sheeting materials, improve and validate unpaved mine road friction supply estimates. This will contribute to improved road design, management and 24×7 operability decisions and contribute to a reduction in heavy vehicle loss of control incidents on gravel-surfaced mine haulage roads.Citation:Thompson, R and Tulloch, D, 2016. What's Stopping You? The Role of Sheeting Material Selection in Safe Haulage Operations, in Proceedings Ninth AusIMM Open Pit Operators' Conference 2016, pp 253–264 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 15, 2016

By P Woodward, T Ly, N Muhamad

OZ Minerals' Prominent Hill copper-gold concentrator is located 650 km north-west of Adelaide in the Gawler Craton of South Australia. The concentrator was built in 2008 and commenced commercial production in early 2009. The Prominent Hill concentrator is comprised of a conventional grinding and flotation processing plant with a design capacity of 8 Mtpa. The flotation circuit includes six rougher cells, an IsaMill for regrinding the rougher concentrate and a Jameson cell preceding the three stage conventional cell cleaner circuit.Since its commissioning, the Prominent Hill flotation circuit has been the focus of a series of projects aimed at continual performance improvement. This has been achieved by a systematic approach of project identification, evaluation and implementation which has led to a progressive improvement in flotation performance. Innovations that have been successfully implemented include aspects of cell design and operation, and reagent suite optimisation.Improvements to the mechanical cells initially focused on the installation of a modified rotor-stator design in the rougher circuit, as recommended by Outotec. Isolated cells were fitted with this technology and proven to provide a benefit for copper recovery before the design was trialled in subsequent cells along the bank. Based on this success, further modifications were made to other aspects of the rougher and cleaner cells.Laboratory trials conducted at Prominent Hill involve a screening process identifying potential reagents from a list of products, which are then rigorously tested in the laboratory before one is selected for trial in the concentrator. Where these reagents have demonstrated a statistical improvement in performance they have typically been incorporated permanently into the flotation circuit. This paper discusses the process of continual improvement at the Prominent Hill flotation circuit and the optimisation achieved by the implementation of key initiatives.CITATION:Woodward, P, Muhamad, N and Ly, T, 2013. Optimisation of the Prominent Hill flotation circuit, in Proceedings MetPlant 2013 , pp 431-444 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

By S K. Panda, M A. Van Ende, S Chatterjee

Tata Steel Netherlands (TSN) aims to reduce its CO2 emissions by 35–40 per cent by 2030 and become CO2 neutral by 2045. A first step to reach these targets is via the utilisation of an Electric Arc Furnace (EAF), which will run on a mixture of high proportion of Direct Reduced Iron (DRI) and scrap. For an EAF operation, optimisation of slag chemistry is important to achieve the right mix of basicity (for refining especially dephosphorisation), foaming, volume (rate) and refractory life. Slag composition and rate can vary widely depending on the process variables like charge mix, charge composition, feeding rate, oxygen lancing, external carbon injection/addition, fluxing and refractory erosion/corrosion. Moreover, it is important to note that the slag composition and rate are ‘transient’ parameters and change throughout the heat. This makes all the dependent phenomena and/or outcomes transient as well. To describe all these effects simultaneously and be able to realistically simulate the EAF operations, a validated dynamic process model is important in the absence of real plant data. In this study, a validated dynamic EAF process model based on the concept of Effective Equilibrium Reaction Zone (EERZ) has been utilised to analyse the impact of high DRI industrial scale EAF operations on the transient slag characteristics – including slag volume (rate), composition, phases, solid fraction and viscosity. Simultaneously, the model is able to predict the impact on steel and offgas characteristics. Case studies were performed with 70 per cent DRI:30 per cent scrap mix considering both low and high-grade DRI. Both melting and refining aspects of the process including continuous feeding, arcing program, carbon addition, fluxing and oxy-lancing were considered.

Jun 19, 2024

By Kavanagh M. E, Henley R. W

The Meekatharra mining district lies in the northern pan of the Murchison Province of the Archaean Ynlgam block of Western Australia. Since dis- covery of the Paddy's Flat belt in the district in 1897 total gold production has been 67 tonnes and a further 33 tonnes in resources have been defined by drilling. The Paddy's Flat gold deposits occur within the Gabanintha Formation, a basal formation of the Murchison greenstone sequence containing komatiitic basalts, ultramafics and minor banded iron formations. The regional control on the distribution of deposits is an anastomosing shear belt which extends over 350 km and incorporates the Mt Magnet, Reedys and Meekatharra deposits. The following gold deposit styles may be recognized based on lithological association and alteration: Albite porphyry hosted, Carbonate-fuchsite- quartz alteration hosted deposits, Banded Iron Formation hosted sulphide replacement gold deposits and quartz vein deposits. With the exception of the banded iron formation hosted deposits, the Paddy's Flat alteration zone shows strong similarities to the alteration styles at Kerr-Addison (Ontario).

Jan 1, 1991

By S B. Fitch, S A. Wilson, A J. R Barr, P R. Searle

Improving the safety culture and performance of any operation is a fundamental goal of every mine operator. Methods of implementing, or changing a culture have developed from the early methods of operant conditioning, for example rewarding crews for achieving nominated safety milestones i.e. 3 months Lost Time Injury (LTI) free through to the current model of engaging a workforce through education and empowerment. As a large scale and mature operation with multiple contractors, Telfer has been exposed to numerous programs throughout its history. This has provided the opportunity to build on and complement these systems by integrating key elements from each. SAFE 360° is a new approach developed to engage the workforce in a holistic approach to encourage positive behaviours across all facets of an individual’s life which results in a focus on situational awareness at all times, rather than being workplace specific. It is based on three key modules: • Emotional Intelligence • Mindfulness • Situational Awareness Each module has a series of modules that help enhance the individual’s sense of self, leading to an ability to self-reflect and self-manage whilst empowering them with the moral courage to challenge their peers to raise standards. Since commencing this SAFE 360° behavioural safety risk management journey in November 2017, we have witnessed a change in the way our workforce engages with each other, their workplace and with management. There has been an increase in hazard perception, identification and ownership of issues, and we have seen a significant decrease in site TRIFR rate from 13.7 to 5.7 (as of April 2019). This paper will provide an overview of the program, how it has been implemented, case studies to demonstrate outcomes and KPIs used to measure effectiveness.

Mar 15, 2021

By D Andrew, G Stanway, P Mahoney, C Griebel

The iron ore mining industry is currently going through an adjustment from high to more moderate growth as China’s economy transitions from capital-intensive investment to a more services-oriented economy. We are now witnessing a renewed focus on productivity improvements and cost savings as planned expansions are completed. Despite the scale and importance that the mining industry plays in the global economy, innovation literature is generally more targeted at faster-moving industries with shorter innovation timeframes and lower capital requirements. To fill this gap, VCI set out to understand the state of innovation in the mining industry in 2014. This State of Play report aims to give an objective appraisal of the strengths and weaknesses of innovation in mining. The report has three sections covering both the structure and delivery of innovation in mining:Ecosystem – focused on understanding how the iron ore mining innovation ecosystem system works, including the roles of large and small miners, service companies, researchers and governments. Our recommendations focus on what is required for the system to work well and improve the level and quality of innovation in the industry.Strategy – how do companies define their innovation strategy in relation to their corporate strategy? How are these related to prevailing global and industry trends? How do they communicate this with their business? How successful are they? These are among the questions that this section attempts to answer. Our recommendations are pitched at the executive leadership of iron ore mining and service companies.Delivery – focused on how companies develop and deliver innovation, looking at the success of different structural options, leadership and culture, partnerships and the best approaches to change. Recommendations are aimed at improving outcomes within the iron ore mining value chain, including the role that suppliers play.CITATION:Stanway, G, Mahoney, P, Andrew, D and Griebel, C, 2015. Understanding the state of innovation in the iron ore industry, in Proceedings Iron Ore 2015, pp 631–646 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

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 Levett, O Rondon, I Glacken

Reporting Codes are not prescriptive on methodologies to report or classify Mineral Resource Estimation results, but the assessment of risk and uncertainty is required, and is likely to be increasingly important in future Code updates. The 2012 JORC Code indicates that relative confidence in tonnage-grade estimations should be considered for classification, and that there should be a discussion of relative accuracy and confidence levels in the Mineral Resource Estimate. These considerations are also relevant to the drill hole spacing required for various classification categories, along with other geological and data quality criteria. This paper summarises the theory, principles and current practice of various drill hole spacing analysis techniques for both achieving a desired level of resource categorisation and for optimising grade control or resource drill-out costs. The authors provide practitioners with a guide in their use to assess uncertainty and relative accuracy, as illustrated by a number of case studies. While all drill hole spacing studies rely on the assumption of consistency of the continuity model from current to future drilling, the range of methods available provide much more objective outcomes than previously adopted ‘rules-of-thumb’.

May 24, 2023

By D Kentwell

IGO Ltd’s (IGO) Nova Operation (Nova) is 160 km east-north-east of the town of Norseman in Western Australia (WA). Discovered by Sirius Resources NL (Sirius) in 2012 and acquired by IGO in 2015, the Nova-Bollinger Deposit (Nova-Bollinger) occurs within the Fraser Zone of the AlbanyFraser Orogen. Nova-Bollinger is a complex nickel-copper-cobalt (Ni-Cu-Co) magmatic intrusive sulfide deposit, which is characterised by high-grade folded and undulating breccia lodes that host the bulk of the payable metals. Significant sulfide mineralisation is also found in several magmatic intrusive styles including net-textured, disseminated and blebby styles. A smaller but material volume of sulfides has also been remobilised into the deposit’s footwall rocks as ‘stringer’ bands in metasediments, or as discrete massive sulfide lenses. When interpolating Mineral Resource estimate (MRE) block grades in the presence of locally varying grade connectivity trends, such as folds or undulations, the sample search neighbourhood, which is used to identify the composites subset that is used for each block estimate, should be oriented to match the local trends. In theory, the most robust method of estimation where locally varying angles (LVAs) are applied to search neighbourhoods, are techniques where the composites and the blocks to be estimated are transformed to an unfolded coordinate system (UCS). However, UCS methods can be tedious to implement and require subjective decisions to be made that cannot always be fully defended. An alternative LVA method commonly used in the industry is dynamic anisotropy (DA), which is much simpler to implement and is often assumed (but not that often demonstrated) to result in similar results to UCS-style estimation. In 2018, Nova’s Mine Geology team (MGT) estimated the grades and density of the Nova-Bollinger MRE using the UCS approach. For the 2020 MRE update, Nova’s MGT tested and compared the USC grade interpolation method with the DA approach. As applied to the Nova-Bollinger’s 2020 MRE, the comparison, advantages and disadvantages of the two estimation methods are the subject of this paper

Mar 22, 2022

By Smele J. S, Dawes W. D

In recent years there has been a trend among mining companies to diversify exploration and development away from the countries that have dominated mining activity for the latter half of this century. With some exceptions, this trend is accelerating and is a function of the recognition that many parts of the world, with no previous exposure to modern exploration, are endowed with considerable mineral potential. In addition coincident with changing political and economic circumstances, many countries have recognised the benefits of attracting international mining investment and have radically changed policies, fiscal and legal regimes so as to encourage exploration and mining. Some countries, however, have not readily accepted mining for cultural or social reasons and have yet to make effective changes to mining legislation. For historical reasons, other countries may have little or no direct experience of western economics, nor may they fully recognise the need for stability and competitive fiscal and legal systems to attract foreign investment. Not all ventures in new countries have been commercial successes and there have been some lamentable and recent lapses from grace. Company strategies, company standards and management objectives can also vary widely from company to company. What may be an acceptable risk or rate of return for one may be completely

Jan 1, 1997

By A Kleinitz, J Halilovic, K Trappitt

Mine operators use grade control to determine the destination of each block of material in the mine. In polymetallic mines, grades are best expressed in dollars: the Net Smelter Return, NSR, per tonne. To estimate NSRs, geologists working on grade control develop models for each geometallurgical domain in the mine. These models may incorporate observations on the mineralogy and grain sizes of the material being examined. The site’s mill operators contribute to the models by providing geologists with statistical analyses that relate assay results and mineralogical compositions to metallurgical parameters, such as the rates of recovery of each economic metal to each of the concentrates produced, and the compositions of those concentrates. The team responsible for sales and marketing of the site’s products contributes to the NSR models by providing details of the costs of shipping concentrates to smelters and refineries; and by providing figures that are specified in the smelter contracts, such as the payability of the metals in each concentrate and the fees charged by the smelter. The mill operators also provide, for the NSR models, equations to estimate the rates of recovery of deleterious materials to each concentrate. Deleterious materials comprise mostly halogens and amphoteric elements, both of which reduce the efficiency of smelters. Furthermore, deleterious materials such as antimony and arsenic may be poisonous to people and to the environment. The sales and marketing team provide specifics of the penalties that smelters impose upon deleterious materials. These penalties may reduce NSRs by tens of percent, possibly to levels below the cut-off grade. Thus, in the blocks that are subject to grade control, mine geologists monitor not only the concentrations of economic metals, but also the presence and abundance of deleterious materials. The preparation and maintenance of models, to estimate NSRs and to assess changes in the levels of potentially toxic materials to be mined, requires close and continuing consultation between corporate departments. There must be strong communication of mine geologists with the mill operators; with the people who market the mine’s concentrates; and, should there be a risk of encountering toxic levels of deleterious materials, with the mine’s health, safety and environmental officers. This co-operation could require radical changes in the structure of many organisations. However, experience suggests that such changes can significantly improve the profitability of a mine.

Mar 22, 2022

By P J. Handley

"Predicting how coal seams will be beneficiated through the coal handling processing plant (CHPP) has long been challenging within BHP Coal. Various coal seams from different areas are mined and stockpiled separately, often depending upon a deleterious coal quality parameter; high/low trace elements for example. These stockpiles are then fed in different ratios into the CHPP to produce the desired product/s. In understanding the washability characteristics of the feed source, mine geologists and process engineers work together to improve the beneficiation of different coal materials through the CHPP.For the majority of the BHP Coal deposits, the washability data is available for the coal seams across the deposits. However, no previous standardised modelling and prediction technique existed that could ensure the correct information was available for forecasting and refining CHPP processes. This paper will discuss the steps undertaken to implement a geometallurgical prediction tool that simplified and streamlined the washability modelling and yield estimation process. The value realised to the BHP Coal assets resulting from this process was: improved compliance to plan increased throughput increased CHPP recovery through improved efficiencies and increased revenues.CITATION:Handley, P J, 2017. Washability modelling and estimation techniques used to improve coal handling preparation plant beneficiation, in Proceedings Tenth International Mining Geology Conference 2017, pp 327–336 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 20, 2017

By R J. Butcher

Many deposits have been evaluated as potential block caves over the last 20 years due to the perceived benefit of low operating costs. However, block cave projects are typically capital intensive, with mass mining providing high throughput rates that required large investments in mining, processing and utilities infrastructure. While the key economic metrics in deciding to proceed with a caving project are typically net present value (NPV) or internal rate of return, these may not represent the best decision metrics for some companies. Where a caving project is competing for scarce capital amongst other projects in a company’s portfolio or where the caving project is the only project being evaluated by a company trying to raise capital, other metrics may be more appropriate. This paper explores the use of present value ratio and the minimising of maximum negative cash flow as suitable metrics in determining alternative strategies. Trade-offs between optimising for economic value and capital efficiency measures allow for decision-makers to evaluate potentially higher-risk, higher-capital and maximum NPV projects against lower-risk, lower-capital projects.CITATION:Stewart, C A and Butcher, R J, 2016. Block cave evaluation, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 809–816 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

The problem of manufacturing from sulphuric 'acid and Christmas Igland "A" phosphate, superphosphate of acceptable physical condition and agronomic phosphate availability, is directly related- to the crystallisation of a reac- tion product, monocalcium phosphate monohydrate. Two solutions to the problem, vacuum drying the superphosphate and calcination of the ore before reaction with acid, are discussed.

Jan 1, 1971