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Following a decline in direct and indirect employment in the minerals industry between 2000 and 2003, the situation reversed in 2004 and employment rose by 12 per cent. Furthermore, there are forecasts of continuing employment growth in the minerals industry in the immediate future. For those of us charged with promoting the virtues of a career in the minerals industry this is encouraging news, as it provides us with the evidence to promote the increasing employment opportunities of a healthy and vibrant industry. However, for many others û particularly the employers in this industry û the news is not so rosy. The jobs are there, and in increasing numbers, but the workers arenÆt! Employers right across the industry are finding it increasingly difficult to fill vacancies with suitably qualified and skilled employees and the competition is becoming fiercer. In the minerals and energy sector, questions are being asked and solutions sought on the industryÆs ability to attract and retain a skilled workforce. From many quarters û industry, government and the education sector, calls for urgent action are becoming louder. The reasons for this are well known û the nature of the work, the remote location, perceptions of the industry, an aging workforce, the gender imbalance, the shrinking demographic of school leavers. It is the latter I wish to focus on û the Generation Y demographic û those who have recently left school, those who are in higher education or have recently entered the workforce, or those who are still at secondary school. These young people are the next cohort of potential employees for the industry. But our need for them appears to be greater that their perceived need for us! How do we engage them so they are informed about the industry? How do we inform and advise them so they are prepared to consider further education and training in disciplines and skill areas relating to our industry? How do we guide and motivate them to give it their best shot and work in it û at least for part of their working life? These are fundamental questions that many within the industry have been grappling with for quite some time. Let me share with you some of the strategies that the Minerals Council is implementing to address this issue.

Jan 1, 2005

By J Langhans, Y Choi, Q Wang, J Y. Baron, P Kondos

Barrick has successfully developed the thiosulfate leaching process to treat sulfidic high preg-robbing ores. The process was developed through rigorous bench test programs and proved in pilot campaigns and demo plant operations. The process uses calcium thiosulfate as a leaching reagent, resin for gold recovery with sulfite/trithionate elution and reverse osmosis as a mean of reagent recovery. The thiosulfate leaching plant is under construction as a brownfield project and the start-up is planned in 2014 at Goldstrike, Nevada, USA, one of BarrickÆs operations.CITATION:Choi, Y, Baron, J Y, Wang, Q, Langhans, J and Kondos, P, 2013. Thiosulfate processing - from lab curiosity to commercial application, in Proceedings World Gold 2013 , pp 45-50 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By S G. Hagemann, M E. Barley

The Mt Tom Price deposit is a world-class high-grade hematite deposit in the Hamersley Province of Western Australia with an original resource of 900 Mt of almost pure hematite, averaging 63.9 wt per cent Fe. Petrological and geochemical studies at both the Southern Ridge and the North deposit at Mt Tom Price have identified three hypogene alteration zones between unmineralised BIF and high-grade iron ore: distal magnetite-siderite-stilpnomelane; intermediate hematite-magnetite-ankerite-talc-chlorite; and proximal martite-microplaty hematite-magnetite-apatite alteration zones.Fluid inclusions trapped in siderite within the distal magnetite-siderite- stilpnomelane alteration zone at the North deposit revealed primary high salinity (25.5 eq wt per cent NaCl-CaCl2) inclusions that homogenised between 107¦ and 142¦C into liquid. Fluid inclusions trapped in ankerite within ankerite-microplaty hematite veins in the intermediate hematite-ankerite-magnetite-talc-chlorite alteration zone at the North deposit revealed mostly H2O-CaCl2 pseudosecondary and secondary inclusions with salinities of 22.4 - 25.4 eq wt per cent and 22.9 - 25.9 eq wt per cent CaCl2, respectively. Pseudosecondary inclusions homogenised between 153¦ and 449¦C and secondary inclusions homogenised between 103¦ and 157¦C. Fluid inclusions trapped in apatite within talc-microplaty hematite veins in the intermediate hematite-magnetite-talc-chlorite-apatite alteration zone at Southern Ridge revealed that primary, medium salinity (7.0 - 9.0 eq wt per cent NaCl) inclusions homogenised between 181¦ and 257¦C and primary high salinity (22.8 - 25.9 eq wt per cent CaCl2) fluid inclusions homogenised between 118¦ and 257¦C into liquid. Microthermometric analysis of quartz from quartz-hematite veins from the Southern Batter Fault, Southern Ridge show a complex fluid inclusion history. Primary fluid inclusions consist of: low- and high-salinity H2O-NaCI inclusions trapped at temperatures of approximately 140¦ to 230¦C; vapour-rich inclusions of unknown compositions; and æcomplexÆ salt-rich (Ca, Mg, K and Na inclusions).Secondary inclusions consist of medium-salinity fluid inclusions trapped at temperatures of about 140¦ to 280¦C.A two-stage hydrothermal model is proposed for the formation of both the Southern Ridge and North deposits. Early 1a hypogene alteration involved the release of hydrothermal NaCl-CaCl2-rich (25.5 eq wt per cent) basinal brines (110¦ - 150¦C) from the underlying Wittenoom Formation and directed upward along normal faults and focused within the silica-rich rocks of the Dales Gorge Member, by the shales of the underlying Mt McRae Shale Member and overlying Whaleback Formation. Within the Dales Gorge Member hydrothermal basinal brines migrated laterally within large-scale folds with permeability controlled by shale bands and the NW trending dolerite dyke sets. Fluid rock reactions transformed unmineralised BIF to magnetite-siderite-iron silicate BIF, with subsequent desilification of the chert bands. Stage 1b hypogene involved an increase in temperature of the hydrothermal, CaCl2-rich saline (24 eq wt per cent) basinal brines (250¦ - 300¦C) resulting in formation of hematite-ankerite-magnetite-talc-chlorite alteration and the crystallisation of microplaty hematite. Late stage 1c hypogene alteration involved the interaction of low-temperature (~120¦C) basinal brines with the hematite-ankerite-magnetite mineral assemblage. At the Southern Ridge deposit this process was very intense (ie high fluid flux), therefore resulting in the almost total removal of ankerite and resulting in the increased porosity of the ore. Stage 2 supergene enrichment in the Tertiary resulted in the removal of residual ankerite and apatite and the weathering of the shale bands to clay.

Jan 1, 2005

By Blain CF

For all mineral resource-based companies, it is important to reach the right balance of investment between acquisition and exploration to allow the best chance of achieving long-term corporate goals. The Broken Hill Proprietary Company Limited (BHP) provides an excellent example of success from generative exploration and supports the belief that exploration can be justified, not only in terms of investment criteria, but also because it is essential to a company wishing to build a dynamic profitable growth path based on world-class deposits as cheaply as possible. BHP was incorporated in 1885 to mine a lead/zinc/silver discovery at Broken Hill. The Company has since gone through a steel development phase (1911-1965) and is now in a major phase of growth partly based on exploration success. This third phase was marked by decisions taken in the 1950's to search actively for mineral and energy resources above and beyond the requirements of the steel industry. The commercial successes of this period have been Bass Strait oil and gas, Groote Eylandt manganese, Deepdale iron ore, Gregory coal and Carnilya East nickel. In total at least 22 new resource discoveries have been made in the last 25 years, of which 11 have been developed and several are undergoing feasibility studies. A financial analysis shows that the real value of the returns seeded by discovery covers the real exploration cost many times over. Moreover, the major discoveries have had a spectacular impact on the growth and development of the Company. BHP's present exploration effort is directed towards geological targets which most frequently meet attractive financial criteria and also promote diversification from steel-related earnings.

Jan 1, 1986

By M I. Pownceby, S Hapugoda, H Han, E Donskoi, L Lu

Iron ore sinter mineralogy and its associated macro-/micro – structure has a strong impact on sinter quality. At a macroscopic scale, sinter ideally consists of a strong, porous matrix which bonds relict ore nuclei together. Microscopically, the sinter matrix (solidified from the melt part of the initial sinter mix) generally consists of complex calcium ferrites known as SFCA, secondary magnetite and hematite grains (precipitated from the primary sinter melt), glass and silicates. Depending on the conditions under which the sinter structure is formed, two major forms of SFCA with different morphologies are generally recognised, ie fine micro-platy SFCA (usually termed SFCA-I) and coarse columnar/prismatic SFCA. Detailed optical microscope observations of several pot grate and compact sinter samples revealed the presence of a variety of fine, coarse and dense forms of both types of SFCA. The controlled cooling tests revealed that cooling rate has an impact on the form and size of SFCA crystals. In this work, EPMA analysis of SFCA compositions from a variety of pot grate and compact sinter samples are presented. Results show that the SFCA types exhibit a broad range of complex compositions within the system Fe2O3/CaO/SiO2/Al2O3/MgO/TiO2/MnO2. Although SFCA-I and SFCA are known to be crystallographically distinct and with different, well-defined ranges in composition, there was considerable overlap in compositions of the experimental sinter samples. The development of SFCA textures depend on several parameters including the local chemistry and conditions including the maximum temperature attained and the cooling rate, within the sinter bed, thereby suggesting that SFCA identification based on morphology alone may be erroneous.

Nov 8, 2021

By J Tibbett, F T. Suorineni, B Hebblewhite

Block caving is an important mining method for the future economic exploitation of large, low-grade, steeply dipping orebodies. While block caving is not a new method, there are still many unknowns surrounding the mechanics driving the process, particularly as we are forced into deeper, higher-stressed and stronger ore deposits. The caving industry is desperate to provide some explanation behind the myths of caving geomechanics to better predict and manage current caves and caves of the future. Large amounts of data are collected to help understand caving, but it is not fully utilised and current approaches for analysing the data are capacity limited. The application of virtual reality and scientific visualisation (VRSV) technology to visualise and analyse block caving is a critical future component in the assessment toolbox. VRSV enables large, complex, multidimensional data sets to be analysed and the power of human visual problem solving processes to be utilised. Block caving is a complex system and needs to be analysed as a system, rather than looking at individual factors one at a time. A software module has been developed at UNSW Australia for use in the advanced visualisation interactive environment for analysis of the block cave mining system (BCMS). This fully immersive, 3D virtual assessment tool shows exciting potential and is used to analyse the BCMS with a close linkage to time (ie the chronological occurrence of data). This tool will enable a true investigation into the cause and effect relations within the BCMS. Current research is investigating Newcrest Mining Limited’s Ridgeway Deeps operation and is aiming to turn some of the cause/effect relationships into increased geomechanics understanding to provide improvements to ground control management. This paper outlines the methods of assessment used to analyse BCMS geomechanics with VRSV and shows the potential of the software module for BCMS analysis.CITATION:Tibbett, J, Suorineni, F T and Hebblewhite, B, 2014. The application of virtual reality technology and scientific visualisation to the understanding of block cave mining systems, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 195–200 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By M Gao

Six new IsaMills were installed for the George Fisher flowsheet in the Lead/Zinc Concentrator of Mount Isa Mines to produce a product P80 as fine as seven microns. The objective was better liberation of galena and sphalerite. The IsaMill commissioning was completed by the end of 1999. The six new IsaMills were running to the metallurgical specifications almost immediately after start-up. This paper reports the performance of the George Fisher IsaMills in the zinc circuits and some of the latest development in the IsaMill designs and maintenance during George Fisher commissioning.

Jan 1, 2000

The green field discovery of a two million ounce high-grade refractory gold ore deposit in the Indonesian Province of Sulawesi Utara, led Newmont to utilise its proven technical expertise in dry grinding and whole ore roasting to develop a 2000 tonne per day, 160 000 ounce per year operation in this remote and picturesque location.Located at an elevation of 250 in above sea level and ten kilometres to a deep water natural harbour, the hard rock open pit mine, process plant and infrastructure facilities were built to budget at a capital cost of US$132 million. The plant was commissioned with oxide ore, with the first gold poured in March 1996 and with refractory ore in January 1997. The operation rapidly met its production targets because of extensive forward planning and training programs developed for the local workforce. The presence of steep topography, fertile coastal plains, high rainfall, high seismicity of this location led to the decision to dispose of neutralised tailings in deep water off the coast instead of impounding tailings in a dam. This paper describes the development of the project and the challenges in developing a gold operation in a remote location which lacked infrastructure, the steps taken to ensure a smooth commissioning, and the selection of the workforce to operate a technically sophisticated facility.

Jan 1, 1997

By A Yáñez, P Vallejos, R Grau, J Yianatos

In flotation cells, especially in large flotation units, froth management is a crucial variable that should be considered during the design phase or optimised to improve the performance of existing flotation circuits. This paper presents a simulation evaluation of the effect of launder design on the metallurgical performance of an industrial flotation circuit consisting of five TankCell® e630 (630 m3 ) cells in a Cu rougher duty. This analysis was carried out using a new industrial simulator, which was built on a wide database collected from many industrial concentrators. This tool is currently incorporated into HSC Chemistry® software and allows evaluation of the effect of launder design on mineral froth recovery, water recovery, entrainment, and other variables to be quantified. The industrial flotation circuit was evaluated under different launder design scenarios, considering an actual flotation circuit that includes TankCell® e630 cells for calibration and as a reference (baseline). Firstly, two different designs were evaluated in the full circuit: a standard launder design and a new launder technology. It was found that the new launder technology enabled improvement of the mineral recovery along the circuit, mainly for coarse particles, due to the improvement in froth mineral recovery. Next, the partial upgrade of the launder design along the circuit was analysed. Thus, the new launder technology was evaluated in the first and the last two cells of the bank. The results showed that upgrading the launders in different cells along the circuit delivered an increase in the final recovery with respect to the baseline, with a partial impact on the concentrate grade. However, these changes are less than those when evaluating the full upgrade scenario. A partial launder upgrade either in the first or last two cells of the bank showed similar final recoveries, but the latter enabled a slightly higher concentrate grade (about 1 per cent higher) to be achieved. Finally, the evaluation of launder design using the industrial simulator made it possible to estimate its effect on variables that are not commonly obtained from plant surveys, including froth recovery per particle size, collection recovery per particle size and liberation, gangue entrainment and bubble loading grade.

Aug 24, 2022

By P Kirsch, P Jagals, D Viswanathan, J Shandro, R LaBouchardiere

The planning, design and operation of mines must include the development of positive environmental, community and land-use benefits if it is to achieve good corporate social responsibility and minimise detrimental impacts throughout the life of the mine. Life-of-mine (LOM) planning should, therefore, consider conducting mining activities in the best socially, environmentally and economically acceptable manner, from the commencement of exploration to post-closure of the mine. Current knowledge of LOM activities in relation to public health (life-of-community, or LOC) impacts neither fully captures the full suite of human health and well-being impacts, nor comprehensively informs society on these issues. This knowledge gap is becoming more apparent as public antipathy is increasing towards mining activities within Australia, Canada and globally. The purpose of this paper is to present preliminary and informative results of a literature review to gain insight into the extent of available public health and well-being knowledge associated with mining development. LOM development must also benefit the LOC, in that it must aim to minimise detrimental impacts, and maximise beneficial (including health) impacts on all associated communities. Health planning and programing for mitigation of potential adverse health impacts of mining should extend beyond the scope of work-related injury and illness (resulting from chronic exposure to harmful substances, infectious and lifestyle illnesses), to the health and well-being of workersÆ families and extended associated communities. By mapping the available but rather scarce literature on LOC areas to recognised LOM stages, this review found shortcomings and imbalances regarding research reporting on mining and its health-related impacts in the worker-to-community continuum.CITATION:Kirsch, P, Viswanathan, D, LaBouchardiere, R, Shandro, J and Jagals, P, 2012. Health impacts extend from the life of a mine to the life of a community - Knowledge gaps, in Proceedings Life-of-Mine 2012 , pp 161-168 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

Recovery of gold by smelting zinc dust concentrate has been carried on at Lake View and Star, Ltd., since July, 1930, when the Merrill-Crowe precipitation plant was first put into operation.Part I describes the development of current gold-room practice, commencing with the clean-up of the MerrillCrowe plant, a procedure that has not materially changed since its inception, and then shows how modifications to straight roasting and smelting became necessary, following a gradual increase in the copper content of the ore treated by the mill.Present smelting practice converts most of the copper into a mixed copper-lead matte, thE sulphur being supplied by the addition of flotation concentrates containing about 35% sulphur as pyrite. The process yields gold bullion of a sufficiently high grade to send to the Royal Mint, but until 1943, suffered from the disadvantage of giving matte and slag by-products high in gold and silver, that were not recovered directly but had to be sent to a smelter.Part Il gives details, of experimental work cnrried out since 1943 which led .to a process for the satisfactory and economic recovery of not only the gold and silver, but also the copper from these, hitherto, troublesome by-products. Nevertheless, incidence of matte in a smelt has always been considered undesirable, and it is hoped that eventually it will be obviated by removing most of the copper from the zinc slime before smelting.Part III indicates the methods by which this might be achieved, and outlines the experimental work that has been done up to the present.

Jan 1, 1948

By I Minniakhmetov, J Ashford

Orebodies constitute naturally occurring, commonly highly variable concentrations of minerals in the earth’s crust formed through varying and highly unpredictable processes. Orebody knowledge is a core foundation of a mining company’s asset base underpinning all decisions about Mineral Resource and Ore Reserves, future production, development and ultimately the profitability and competitiveness of a mining enterprise. The decision to invest in a mineral project is usually based upon a techno-economic evaluation of the project and having clear approval pathways to gain local community support and address social and environmental impacts. The main objective of the techno-economic evaluation is to determine the optimum development sequence for the particular orebody in question and to estimate the economic viability of the project and the future return on investment to its stakeholders, balancing the inherent value of the mineral in the ground against the costs of development and market pricing. With the exception of market-driven commodity prices, virtually all revenue and cost estimates fundamentally stem from the understanding and subsequent modelling of the orebody. A reliable estimate of the ore deposit grade and other geological value-drivers is the foundation upon which the business case for future mine development and operation is intricately dependent. Orebody knowledge is, therefore, the fundamental driver of the mineral project cycle, influencing the progression of studies and consequently, the resource company’s ability to declare Exploration Results, Mineral Resources or Ore Reserves which govern the source and cost of funding available to the project. Drilling provides a ‘vector’ to the true nature of the orebody and effectively buys time to manage the technical risk associated with the orebody. Despite its perceived high cost, in both time and money terms, drilling is the only available technology for acquiring the necessary orebody knowledge to support technical and economic studies and to minimise orebody-driven cash flow uncertainty and volatility. However, like all costs, pressure to minimise drilling budgets is ubiquitous across the minerals industry. Paired with inappropriate key performance indicators, drilling is often regarded as a cost to be minimised, rather than an investment to be optimised. Furthermore, as future deposits get deeper and more complex, the collection of orebody knowledge is increasingly on the critical path for project development. The increasing cost of data collection pertaining to these deposits increases the temptation to minimise orebody knowledge gathering at the cost of long-term value as the reduction or postponement of drilling results in greater orebody knowledge risk at all stages of the value chain. Indeed the true cost of the decision to drill less is rarely known until the mine is in operation, well after the mine project evaluation team has moved on. This paper aims to promote orebody knowledge as the fundamental source of endogenous project financial risk and, consequently, its critical importance in project financial evaluation. Furthermore, the report documents experimental research into the development of an econometric model for valuing orebody knowledge. Using the density of drilling data as a proxy measure of orebody knowledge, the proposed approach integrates well-established stochastic grade modelling techniques with the mathematical mechanics of Decoupled Net Present Value (DNPV) which, combined with stochastic grade modelling (conditional simulation), lends itself to the financial International Mining Geology Conference 2022 | Brisbane, Australia and Online | 22–23 March 2022 3 assessment of orebody knowledge risk. Based on this approach, a metric is formulated, representing the minimum value of the orebody knowledge added by additional drilling

Mar 22, 2022

By W R. Adamson

Cerro Vanguardia SA (CVSA), property of AngloGold Ashanti, mines gold and silver from a system of vetiforme orebodies located in the south of the Argentine Patagonia, in the Province of Santa Cruz.Surface mining techniques are applied to develop a series of narrow pits with an average waste to ore ratio of 26:1. This quite unique constraint brings into focus the need to maximise inter-ramp and final wall angles, leading to a strong need to optimise wall control drilling and blasting in order to reduce back-break damage to an absolute minimum.The paper describes a program of applied investigation and design modification implemented during?2008?and?2009 in?two?separate pits of Cerro Vanguardia. Three distinct yet complementary damage mechanisms were identified and observed during the field components of the work; vibration induced strain fracturing, surface cratering around blasthole collars and quasi-static loading and unloading of the surrounding rock mass as a consequence of poorly controlled confinement.With these mechanisms identified, a measurement, modelling and modification campaign was conducted in order to reduce the incidence of each source of damage. Interactive design analysis and modelling, near-field vibration measurement, video capture and the application of electronic initiation technology were supported by seed wave modelling and topographic evaluation of the achieved results.Results point to the usefulness of simulation techniques for determining optimum delay timing to reduce vibration impact, while the visualisation of explosive energy distribution produced by drilling and explosive loading decisions assists in reducing the probability of over-confinement.This paper presents relevant aspects of the two fieldwork campaigns:1) describing the application of the techniques, and2) summarising the results obtained.

Nov 8, 2011

By R Thompson, J Miedecke, D Handel, E Tomicek, D Tulloch

"The Mine Haul Road Optimisation Alliance (HROA) is a unique Australian industry–academia collaboration that has been developed to support mine haul road operators. The alliance integrates industry, end-user service providers and academic research expertise in mine haul road design, construction and operation to identify, quantify, implement and monitor the various equipment, materials and road management strategies and solutions required to drive haulage productivity improvements.Initially, a broad overview of the university–industry collaborative landscape is presented, following which the current situation in the Australian mining sector is reviewed both nationally, and on a country-wide basis internationally. This insight places into context the opportunity that strategic collaborations present, to drive productivity and efficiency in mining, while also delivering innovative technology solutions.Following an overview of the HROA collaborative structure, aims and objectives, it is shown how academia and industry collaborations can deliver a more robust and needs-driven solution to mine haul road design, performance and management, especially where integrated solutions are needed. Critically in this approach, implementation and monitoring data provided by industry and service providers alike form the foundation on which to develop research knowledge and innovation that is more responsive to the end-user requirements, typically represented by ‘early goals’ and practical, implementable solutions.The paper concludes with examples of how the alliance collaborations work in practice to deliver focused mine haul road research outcomes, together with the mechanisms used to ensure industry needs are met through end-user driven research solutions for enhanced operational performance.Citation:Handel, D, Miedecke, J, Thompson, R, Tomicek, E and Tulloch, D, 2016. Driving Haulage Productivity Improvements through Industry–Academia Collaboration, in Proceedings Ninth AusIMM Open Pit Operators' Conference 2016, pp 243–252 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 15, 2016

By S Morgan, D J. Bradshaw, S Schwarz

The characterisation of the flotation kinetic response in future mining deposits is important because the flotation response is affected by changes in ore mineralogy. Current methods for characterising the flotation response of different ore types, such as the JK floatability index test (JKFIT) methodology, require at least 10 kg of feed material. In geometallurgical applications, this material is taken from core samples. Core samples are generally obtained using specialised drills and are limited in nature. Thus, it would be beneficial to develop a laboratory technique that required less sample material but still characterised the flotation response of different ore types. The JK mineral separation index (JKMSi) is a small-scale flotation test that requires significantly less feed material (10 g of sample/data point). This study aims to investigate the JKMSi system kinetics and to validate this technique using the JKFIT proven methodology. The JKMSi flotation kinetics were manipulated by varying selected system parameters. The relationship between these parameters and mineral recovery was used to obtain floatability characteristics of the ore. For an ore sample containing chalcopyrite and pyrite, it was found that the chalcopyrite floatability parameters determined from both the JKMSi and JKFIT tests were of the same order of magnitude and the mass fractions of the fast, slow and non-floating components were similar. For pyrite, the floatability parameters were not of the same order of magnitude, but modifications to the test procedure have been identified, which may correct this.CITATION:Morgan, S, Bradshaw, D J and Schwarz, S, 2012. Julius Kruttschnitt Mineral Separation Index - Small-scale test to characterise the flotation response of an ore type, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 159-162 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By H Y. Niu

The coal left in the goaf is easily submerged by groundwater damage. During the mining process of the underlying coal seam, it is necessary to drain the water in the overlying goaf. The coal sample is prone to spontaneous combustion after being soaked in water and air-dried. To explore the effect of micro-functional group transformation of water-immersed coal samples on the spontaneous combustion characteristics of coal samples during the low-temperature oxidation process. Using the experimental method of infrared spectroscopy, the migration law of special functional groups under different oxygen concentrations of water-soaked coal samples was analysed. By means of thermal analysis, the endothermic and exothermic properties of the functional groups in the water-soaked coal samples were studied. The results show that: the higher the oxygen concentration, the more oxygen-containing functional groups in the water-soaked coal sample, compared with the 18 per cent oxygen concentration, the 14 per cent oxygen concentration has a small increase, and the chain length is shortened. The temperature increase together with the oxygen concentration content determines the functional group content, the pyrolysis process produces some functional groups. The lower the oxygen concentration, endothermic rate decreases and endothermic temperature increases, the higher the ignition temperature of coal oxy-combustion, the lower the total heat release, the higher the burnout temperature, and the faster the oxygen-absorbing weight gain and the conversion of functional groups. Below 14 per cent oxygen concentration, the oxidative combustion process will be greatly reduced. The results provide a theoretical basis for preventing long-term water-soaked coal body oxidative spontaneous combustion in shallow buried coal seams.

Oct 12, 2022

By M Jacobs

This abstract discusses a heap leach copper mine that was failing to perform and as a result was not meeting targeted production. The mine had numerous technical challenges including: high water inflows, low levels of geotechnical monitoring, performance issues with mining, resource model and grade control reconciliation issues, and unexplained low levels of performance from the heap leaching operations. A team from various organisations with specialist skill sets including: a forensic accountant, the owner’s representative and a mining engineer, was arranged to visit the site. The task was to investigate the situation and determine what could be done to turn the performance of the mine around. After an initial assessment in late 2018, efforts were directed to better understanding the operations and improving the performance of the site through preventative management. A key part included the creation of production forecasts that could be achieved that would help restore confidence in the operations. Uncertainty in the mine achieving production forecasts and the performance of the heap leaching operations were contributing to the decline of the operations. Investigations uncovered the fact that while the resource model could reliably predict total copper, a lack of sequential leach data meant the accurate prediction of soluble and insoluble copper species, both important for heap leaching, was difficult to do with any degree of certainty. The crushing and mining contractors also appeared to have suffered somewhat from a lack of management by the owner’s team and performance had affected the production of copper. Collaboration and management were used by the team to understand and stabilise the operations. Ongoing collaborative efforts by the management team, site personnel and contractors resulted in a positive outcome for the owners and their mine – and could at yours.

Jun 22, 2022

By J Westh, S Rashleigh, L Gallagher

Mining companies are moving towards automated haul trucks and other equipment. One reason for this is that if automated trucks can operate in a standard pattern over and over again without variation, then human error is reduced, if not eliminated.The challenge for mining production leaders/managers is to ensure operators follow standard operating procedures for load and dump operations, with each operator doing the same thing, every time. However, operators are only human and inconsistent performance is rife at every mine site. The finger may be pointed at the operators for not doing as instructed. The clarity and variability of trainer instructions may be considered causal to the problem. Herein lies the problem. Almost all operators believe they are following the procedure very closely; moreover, they all demonstrate a strong desire to conform to instruction.Using video analysis and feedback, each operator can be shown where and by how much they differ from the benchmark set by their company. Operators, often for the first time, can see definitively what they are doing, compared to industry best practice.The technology utilised by real-time video (RTV) crews measures time, distance and angles. It can overlay the video of the operator at the load site, with video of the perfect pass. Operators are amazed when they see how near to, or how far they are from best practice.The footage and data gathered by RTV assists operators in understanding exactly what adjustments are required to increase proficiency. It also assists load and dump superintendents to identify where in the process they are losing time. When translated to overburden removal or mineral/resource extraction, the result is large production economies without the need for large capital investment in new automated technology.CITATION:Westh, J, Gallagher, L and Rashleigh, S, 2012. Improving safety and mine productivity using real-time video technology, in Proceedings International Mine Management 2012, pp 173-188 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 20, 2012

By Kuganathan K, Potvin Y

Enterprise Mine at Mount Isa is to expand ore production from the current 1.4 to 3.5 mtpa by mining the 3500 Orebody, from which production is scheduled to start in February 1998 making this the deepest underground mine in Australia with its lowest mining horizon at nearly 1.6 km below surface. The following fill requirements were defined for the 3500 Orebody during the feasibility study: 1. a minimum filling rate of 250 ma/h, 2. a curing time of 28 days, and 3. minimum free fill water. This paper mainly describes the investigation of high density and paste fills for the 3500 Orebody. The investigation covered all the key issues relating to fill option selection, including design criteria, material supply and demand assessment, drainage modelling, tailing dewatering method, mix design and a pump loop test. Results of the investigation indicate that both high density fill and paste fill are technically feasible. The investigation has led to the selection of a blended tailing paste for the 3500 Orebody as the paste option has significant advantages over high density fill in stope filling rates and fill reticulation. The blended tailing for paste fill is finer than Isa deslimed tailing but coarser than full plant tailing. The paste fill selected has minimum binder and tailing dewatering requirements while a relatively high filling rate is achieved.

Jan 1, 1998

By S S. Kanchibotla, I Brunton

Most blast fragmentation models assume the rock mass properties, explosive properties and blast design variables to be constants and uniformly distributed within a blast. However, in reality all these input variables vary within a blast resulting in variation in the resulting fragmentation size distribution. A stochastic modelling approach is introduced in this paper to quantify this variation. This technique takes the input variables as statistical distributions rather than constants and through several thousand iterations, generates a statistical representation of the expected fragmentation resulting from a production blast. A case study of three production blasts from a large open pit mine are presented and the modelled fragmentation æenvelopeÆ shows good agreement with the fragmentation æenvelopeÆ estimated from Split image analysis. The various blast-related parameters influence different parts of the fragmentation distribution, eg rock strength and explosive velocity of detonation have most impact on the fines. The technique is used to identify the parameters that have the greatest influence on various size fractions. Such an analysis will be useful to direct resources to efficiently minimise the variation.

Jan 1, 2001