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By T Roberts

The transition of mechanical cooling refrigerants from their inception in the 1800s through to the current day has been driven by several factors. Original refrigerants such as sulfur and carbon dioxide, chloromethane and ammonia, whilst effective came with toxicity and/or flammability issues. In 1930 DuPont trademarked a new synthetic refrigerant known as Freon® 12, this development was the introduction of ‘chlorofluorocarbons’ (CFCs).Throughout the 1930s and 1940s additional synthetic refrigerants were developed, namely Freon® 11 and Freon® 22. Due to their non-toxic and non-flammable characteristics, synthetic refrigerants were extensively used for domestic, commercial and industrial applications for the next 60 years.In 1985, one of the first scientific papers suggested a potential mechanism linking CFCs and areduction in the density of the ozone layer. In 1987 the Montreal protocol is ratified; it is the first UN treaty to be ratified by every country on earth. Due to CFC’s ozone depletion potential (ODP), the treaty required the consumption of CFC’s to be reduced by 50 per cent over the next ten years. By 1996 the phase out of CFC’s (Freon® 12) is completed, the phase out of HCFC (Freon® 22) refrigerants comes into effect.On 1 January 2018 the phase down of HFC’s begins. Whilst having zero impact on the ozone layer HFC refrigerants have high global warming potential (GWP). As we transition through the HFC phase down (2018–2035) we are beginning to see the emergence of what some consider to be the fourth synthetic wave, hydrofluoro-olefins (HFO’s). HFO’s and their blends have zero ODP and low GWP’s, ranging from 150 to less than 1. The reduction in GWP with HFO’s typically comes at the expense of flammability, which is not ideal. Each refrigerant has its optimal application, therefor when considering refrigerant choices for mining systems, a complete assessment of the environmental, health and safety, efficiency and commercial impacts should be considered now more than ever.

Oct 12, 2022

By J Balzary, A Mohais

Dynamic market and operating conditions, coupled with an environment in which multiple objectives and trade-offs are common, pose major challenges for planners and schedulers working in any mining entity. Many mining companies recognise the need to shift from a siloed mining-focused push model to an integrated value chain, demand-driven approach, but there are still fundamental barriers in business process and the supporting technology preventing a consideration of end-to-end optimality.This paper presents some elements of experiences working with companies to adopt such advanced approaches. In addition to algorithmic elements, an approach to phased and gradual deployment of progressively more sophisticated optimisation models is described. From a practical software adoption perspective, it is believed that this last concern is also of primary importance. Next generation approaches to the optimisation of complex bulk commodity demand chains, namely iron ore and coal are presented, with case studies in the world’s largest integrated operations in Western Australia and Queensland from the raw material mined through to market. Utilising accurate simulation models supported by metaheuristic optimisation techniques, a range of ways to engineer a dynamic decision support framework that can adapt and change with the inevitable changes in commodity markets is explored. Objectives such as total revenue, margin, cost, NPV, throughput, asset utilisation, contractual penalties and bonuses, and energy consumption can be managed simultaneously across the mine, plant, logistics network, port operation, shipping and sales domains.CITATION:Balzary, J and Mohais, A, 2014. Consideration for multiobjective metaheuristic optimisation of large iron ore and coal supply chains, from resource to market, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014, pp 213–222 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By Singh DP, Singh TN

The present study attempts to critically review the pillar-design as required by Coal Mines Regulations of India vis-a-vis latest rockmechanics formulae. Equivalent material modelling was the approach adopted for testing the safety and stability of the pillar sizes predicted by various formulae. Two parameters, considered here for calculating pillar sizes was the stresses acting over the pillars and the strength of the pillars. Stresses acting on the pillars were calculated by the tributary area method. Based on the studies of Coates and Hustrulid, the stress obtained was reduced by 40 percent. For calculating the strength of the pillars, three formulae, namely Holland and Gaddy, Salamon and Munro and Central Mining Research Station, India, were used. The pillar widths were then determined by equating the product of recommended factor of safety and pillar stress with the pillar Strength.

Jan 1, 1992

By S McGregor, J Sharp, I Entezari, T Boulter

The piezocone penetration test (CPTu) is one of the primary screening tools used by the mining industry to evaluate whether tailings are susceptible to liquefaction (static or cyclic). Liquefaction analysis using the CPTu is influenced by the fines content of the soil, and most CPT screening tools empirically use the behaviour type index (Ic) to correct for fines. The issue with this approach is that such empirical relationships have been developed using data collected from natural soils and their applicability to different tailings deposits needs to be studied. In this paper, we explore the use of machine learning to develop a site-specific model to estimate fines content of tailings using gamma piezocone penetration testing (GCPTu) measurements. The results are then compared to the fines content derived from the soil behavior type index (Ic) proposed by Robertson and Wride (1998). A dataset of paired GCPTu and laboratory results were compiled and a support vector machine (SVM) algorithm was employed to calibrate a model to estimate tailings fines content from in-situ GCPTu data. We calibrated GCPTu data to geotechnical 75 μm fines content measured in the laboratory. The geotechnical fines content is the fines content as a percentage of solids. The development dataset was comprised of paired GCPTu-laboratory results collected in 2009-2019 from a mining area with predominately clay mineral and quartz sand tailings. Results show that the developed model predicts the geotechnical 75 μm fines content of the studied deposits with 7.8% error. The Ic based method estimates the fines content with 31% error. Evidently, the Ic method is not applicable to the studied tailings deposits. It is appreciated that many tailings fines do not contain clay, and that the success on this program may not be repeatable everywhere. However, the authors wish to point out that the application of site-specific machine learning algorithms may be used to significantly improve empirical geotechnical parameters.

Jul 1, 2021

By R H DAVIES

Peak Gold Mine is a new gold and base metal mining project being developed by Enterprise Metals (a 100 per cent subsidiary of CRA) at Cobar in the centre of New South Wales. The Cobar district has a long history of copper and gold mining operations stretching back to the 1870s. Extensive gold and base metal mineralisation was discovered at the Peak in 1981 below a series of gold mines which had been active around the turn of the century. Evaluation of the deposit through the 1980s led to CRA's decision to develop the project for production at a capacity of 450 000 tonnes per annum in late 1992. The project has been developed with a green fields approach despite the long history of mining in the local area. This approach has lead to several innovative ideas being trialed at the site which are expected to result in the operation being a low cost producer of gold and base metals.

Jan 1, 1992

The Devonian Mount Morgan gold-copper deposit was situated on the western margin of the Calliope Volcanic Are assemblage, in the northern New England Orogen. Recorded production from commencement of mining in 1882 to mine closure in 1989 stand

Jan 1, 1994

As students progress further into a degree, the decision of vocation selection, and even more importantly û securing employment in a particular industry sector, can become quite daunting. However, with a little initiative, students can overcome these issues by not only researching what employment opportunities exist, but by applying for summer vacation employment. Undergraduate vacation employment, especially with a world-leading hydrometallurgy research organisation such as the Parker Centre, can dramatically alter a studentÆs perspective of particular industries and possibly even alter their selection of vocation pursuits upon graduating. Students can also use vacation employment to enhance their networking capabilities, technical skills and knowledge by dealing with challenging new topics such as sulfur dioxide leaching, which is also discussed in this article.

Jan 1, 2005

As the mining industry looks to new technologies for a safe work environment and increased production rates, so should emergency response teams when dealing with organisational incidents. Implementation of technology has transformed the nature of incidents within the international mining community with lower frequency, high impact events replacing high frequency, low impact incidents of the past. In turn the approach to mines rescue response and preparation has naturally diversified. New rescue technologies when applied effectively can only further advance preparation and the response of mine rescues teams. This paper discusses some of the changes associated with mines rescue as the industry embraces technology. It highlights some recent rescue responses and their approach and gives examples of some of the new technologies being used for improved mines rescue.

Jan 1, 2004

By L Nienaber

Mines, after becoming operational, often retain the same support and reinforcement designs developed in the feasibility study. These designs are conceived from limited drilling data and regional experience, thus having an empirical flavour. Empirical designs are perceived to be conservative, catering for a variety of failure mechanisms, which are not always present in mine development drives.This begs the question: If you were to invest in the necessary resources to obtain sufficient data and complete the required analyses for the different development drives in the mine, to engineer a support and reinforcement scheme with the capacity to match the demand of the rock mass, what is the difference in cost when comparing an empirical design to an engineered design?To answer this question, mine tunnels with different geometries and orientations, where detailed structural data was available, were selected for a comparative design exercise. Material cost, development cost, cycle time and professional fees for engineered and empirical designs were estimated. The outcome is summarised in the following paper that discusses the process followed and the results of the design comparison.

Mar 8, 2011

By J Koshy, M Ralph, P Foley

Mining in the state of Western Australia (WA) formally commenced in the 1840s, and over the ensuing 180 years has evolved to be the epicentre of the Australian mining industry and a significant contributor to the national economy. The lithology of WA is replete with mineralisation that hosts uranium and ‘critical minerals’ required for the global renewable energy sector. The state’s first uranium mine is under development, and high levels of activity are occurring in the state’s nascent critical minerals sector, with 168 WA-based companies pursuing rare earth-bearing minerals, 51 of which are actively drilling on their tenements. WA’s mineral deposits typically contain levels of the naturally occurring radionuclides (NORs) thorium-232 and uranium-238 that are elevated above the global crustal average. Workers are exposed to NORs during the mining and mineral extraction processes, and radiation doses that exceed applicable exposure standards may eventuate. The research traces the history of worker radiation doses from 1977 to 2020, finding the maximum dose was 163.4 mSv, more than eight times the current derived annual dose limit. Whilst 93.5 per cent of all workers received doses of less than 5.0 mSv per annum, the potential for elevated doses is ever-present as witnessed by 10.3 mSv reported in 2009/2010. The increase in activity coincides with a revision of the dose coefficients (DCs) associated with the intake of radionuclides. The research evaluates the revised DCs and forecasts doses from inhalation of radioactive dusts will nearly double, and lead to workers receiving doses exceeding 5 mSv for the first time since 2009/2010. The research finds that the current regulatory framework is fit-for-purpose. However, inter-agency relationships, and the capacity of the regulator to effectively regulate the current and future number of mining operations is questioned. The mining industry is vulnerable to capability and capacity constraints – but has failed to respond to issues in relation to competent radiation safety officers first raised by the Winn Inquiry (Winn, Mathews and Tough, 1984). Disconcertingly, monitoring of worker exposures to NORs reached a nadir in 2021, raising questions as to the veracity of worker doses reported to the regulatory agency. The research recommends personal dust sampling be prioritised.

Apr 16, 2024

IN this paper an attempt is made to describe the sluicing operations on the tin fields of north-eastern Tasmania. No claim is made to completeness, for much of the ground has already been covered, and nothing is to be gained by needless repetition. On this account some portions of the subject have obviously received but scanty attention in order that others may be rather more fully dealt with; for instance, figures referring to the accuracy of various methods of valuing alluvial deposits, particulars of efficiencies, and water duties on both overburden and drift; also, the system of recording water distribution, &c.The plans of the tin-streaming shed, sluice and feed·race, and overburden tail-race represent types of the most modern design.The principal alluvial deposits being worked at the present time are situated either in the ancient or modern bed of the Ringarooma river or its tributaries. This river flowed in a north-easterly direction, receiving numerous tributaries on either bank, and finally emptying into Boobyalla harbour. The most important of these tributaries, from a mining point of view, are the Cascade, Main creek, Weld and Frome rivers (which unite just before joining the modern Ringarooma), Wyniford river, and Bradshaw's...

Jan 1, 1911

By P A. Kirsch, A Hine

Mining is a major global industry that requires the moving of considerable volumes of earth and rock (overburden) to win the valuable ore prior to mineral extraction and processing. As a result of this process, new landscapes are created, both extracted voids and overburden piles, as well as infrastructure for management of mine operations, wastewater, tailings, other raw materials, transportation and extreme rainfall events. Resource companies must develop and obtain regulatory approval for detailed plans that manage this displaced material through all phases of the life-of-mine and rehabilitate the site at the time of closure (including landform stability, revegetation and ongoing management).Individual mine sites operate in long time frames (ten to 50 years), with several mines often operating in the same region, generating cumulative overburden volumes and heavily altering the original landscape. These impacts are universally framed as a negative consequence of the industry, especially by modern society that values natural (and some agricultural) landscapes as pristine and almost sacred. Overburden and tailings are also seen as a problem, and are a significant business cost to mining practice.This paper looks to investigate perceptions of mining and post-mining landscapes, questioning the aesthetically driven emphasis on the ‘natural’. It proposes instead an opportunity to reframe the way we look at overburden and landscape impacts from mining, exploring the possibility of imagined post-mine landscapes unburdened by traditional aesthetic expectations. These landscapes, to be conceived by regional stakeholder roundtables, have the capacity to be built by regional mining consortia as a foundation for sustainable post-mining economies.Post-mine regeneration offers both the motivation and the basic materials to create an altogether new environment from a blank slate. Few circumstances allow the opportunity to truly explore a re-envisioning of the land on a huge scale, and the possibilities merit serious consideration.CITATION:Hine, A?and Kirsch, P?A, 2014. Dreams of futures past – curating post-mining landscapes, in Proceedings Life-of-Mine 2014 , pp 121–138 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By Bush P. R, Hale M, Dixon C. J, Wheatley M. R

Barium anomalies in drainage sediments can act as indicators of barite mineralization and path- finders for lead-zinc mineralization. Their detection in an arid climate has been investigated in two areas of Saudi Arabia. At Rabigh, 150 km north of Jeddah, barium anomalies found in wadi sediments reflect barite veins which occupy Tertiary faults in Precambrian metavolcanics and granodiorite. In the Wadi ad Dawasir area, 650 km east of Jeddah, the sediments of wadis draining the Jabal Tuwayq escarpment have been found to contain anomalous concentrations of barium derived from diagenetic barite in the Sudair formation siltstones and shales. Barium dispersion in these wadis is predominantly clastic. Near to the source rocks, barium occurs in relatively coarse grains of barite. Owing to the three well-developed cleavages of barite, its crystals readily break into cleavage flakes during fluvial transport in flash floods; as a result, the longest anomalous dispersion trains are found in the 250 to 600 um fraction. Wadi sediments finer than 250 um have relatively constant and low barium contents, being dominantly composed of windblown sand.

Jan 1, 1988

In seeking to improve the economic performance of mines, the management or human aspects are usually seen to be quite seperate from, and more significant than, the technical aspects. There are obvious aspects of industrial relations, man-management, skills training and supervision that are currently the focus of efforts to improve the productivity and quality of the mining process. However technology also has a lot to offer. Analysis of the costs involved suggests that innovations leading to improvement in the productivity of the excavation and transport of overburden and the recovery of coal (both in the mine and preperation plant) can lead to improvements in the economic performance of a mine that may outstrip the obvious non-technical or management opportunities for improvement. While there are some innovations currently being investigated within the industry that relate to the design of mining equipment, the type of machinery being used in open cut mines has not changed dramatically over the last twenty five years. It is also likely that mining equipment will remain essentially of the same form in the forseeable future. If significant improvements to mining performance are to be achieved other than by futher increases in the scale of machinery, then we need to seek ways to operate these same types of machines in a more productive and controlled manner. This paper discusses the identification of mining processes the improvement of which is likely to have a significant effect on mining costs and performance. Some areas of current research are discussed and potentially fruitful areas for future development are identified.

Jan 1, 1991

By D Kavanagh, C Michaud

"A continuous improvement initiative was identified at Kalgoorlie Consolidated Gold Mine’s (KCGM) Fimiston open pit with the goal of reducing bench turnover time and increasing shovel digability by improving fragmentation around previously mined-out stopes. In the past, a higher number of blasts than normal would be required to get through a single excavation area where stopes were present. This is due to the limited reach capability of the drilling fleet from safe ground into restricted areas requiring the drilling of the shot to be done in a staged manner. In addition, the holes that were able to be drilled in the area did not remain open long enough to be loaded with explosives as a result of the poor ground conditions surrounding the stopes.Over the last 18 months, KCGM has trialled drill additives to improve blasthole stability, as well as introducing a remote drill rig allowing holes to be drilled in areas previously inaccessible by manned drill rigs. This has resulted in improved penetration rates in bad ground conditions, improved drill hole stability, better shovel digability, and an overall reduction in bench turnover of at least ten days on the benchmarked 126 days average per bench. KCGM is now in the final stages of the improvement project with the installation of a drill monitoring system on the fleet to allow live data transfer back to the office for analysis, as well as providing improved accuracy on drill holes in restricted areas.Citation:Michaud, C and Kavanagh, D, 2016. Reducing Bench Turnover Time and Improving Shovel Digability, in Proceedings Ninth AusIMM Open Pit Operators' Conference 2016, pp 19–27 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 15, 2016

Throughout the study phases (scoping, prefeasibility and feasibility) of new mining projects one is forced to work with and make predictions based upon limited date obtained from diamond and reverse circulation drill holes. These data are extrapolated to determine how much of the valuable metal is present in the ground, how it can be recovered it and the efficiency of this recovery. Mining methods to extract the ore are investigated with forecasts made regarding excavation stoping stability and performance in an attempt to optimise production. Extraction and use of rock mass data for use in characterising the mechanical behaviour of the rock mass is no exception. One often relies heavily upon the use of empirical charts developed over many years on hundreds of case histories based upon rock mass characterisation schemes. This is largely successful and indicative of what one might expect. However specific site characteristics can always play a significant role, and are not necessarily apparent in diamond drill core. Feasibility studies for the Favona orebodies indicated that the rock mass was generally poor to extremely poor, and that stoping conditions would be difficult in all of the orebodies for various reasons. A range stope performances were achieved ranging from very good to very poor and in some cases unexpected results were achieved. A comparison is made between what was actually achieved and what was expected since stoping commenced in 2007. Explanations are attempted for differences in stoping performance and, in some cases, unexpected results at the Favona underground mine are attempted.

Nov 25, 2010

Gold rooms represent a high security area and preventing theft is a challenging task. Where gravity concentrates or high value unit intermediate products are present, particular and specific security procedures must be put in place. This paper describes the development and implementation which reflects best practice in gold room security. Procedures involving key holder systems, key locks, swipe cards and double locks preventing any one person having access to the gold room, including specific procedures for gravity gold concentrators, will be addressed. The use of monitoring and how to deal with alarms and potential hold ups will be reviewed. The use of cameras and archival DVD recorders is common in gold rooms. The use of electronic surveillance, movement detectors, seismic monitors and the two person policy and gold room entry procedures are described, including how to deal with visitors. The importance of confidentiality regarding smelting and gold pick-up days, plus strategies employed to minimise storing large quantities of gold on site will be presented. The role of metallurgical accounting in providing quality auditable information and the minimum standards of record keeping required is discussed. The role of the Gold Squad will be outlined. Regular auditing and risk analysis and several case studies are cited where security was deficient or improved.

Aug 1, 2010

Geological hazards such as faulting, basement ridges, and zones of "thin" (

Jan 1, 1998

By Y Li

An ilmenite ore from the Murray Basin was initially characterised using combined X-ray Fluorescence Spectroscopy (XRF), X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Electron Probe Microanalysis (EPMA) techniques. XRF analysis showed the ilmenite sample contained 58.7 wt per cent TiO2 and 26.2 wt per cent Fe2O3. Major impurities included: Cr2O3 (4.5 wt per cent), Al2O3 (2.7 wt per cent), SiO2 (1.9 wt per cent), Mn3O4 (1.5 wt per cent) and MgO (1.1 wt per cent). Manganese and magnesium were present as solid solution components within the ilmenite lattice while the elevated Al2O3 and SiO2 levels were due to separate aluminosilicate gangue minerals. Chromium was associated with discrete chrome spinel gangue phases of variable composition, (Fe,Mg)(Cr,Al)2O4. Quantitative XRD analysis of the sample identified rutile (12 per cent), ilmenite (11 per cent), and pseudorutile (67 per cent) as the main titanium-containing phases and chrome-rich spinels (seven per cent) as the major impurity phase. Minor quartz, aluminosilicates, zircon and monazite were also present. The ilmenite was mixed with synthetic graphite, pressed into pellets and reduced carbothermally in nitrogen at 1200 and 1400°C with C/O molar ratio of 1.2. Titanium oxide in the ilmenite was converted to titanium oxycarbonitride. Iron oxides were reduced to metallic iron. The Changes of impurities as a result of reduction was examined by SEM and EPMA analyses. Iron and chromium oxides within Fe-rich chromite were reduced to form a Fe-Cr-C alloy. Mg-rich chrome spinels were partly reduced at 1200°C. Zircon particles were not reduced at 1200°C, but were significantly reduced at 1400°C, with the particles becoming porous and the silicon being removed.

Oct 5, 2011

Two key elements in the design of a pastefill or high density hackfill system are the preparation of the backfill material and its distribution underground. This paper examines these two areas. Owing to the essentially impervious nature of total mill tailings, preparation of pastefill and high density fill from current tailings involves a physical dewatering process. There are currently three methods available for this process: I. Vacuum or pressure filters. These represent the 'traditional' approach to the preparation of pastefill. 2. Paste production storage mechanism. This is a thickening/storage mechanism developed with the specific objective of producing paste/high density backfills. 3. Fluidization. This system utilises silos fitted with simple dewatering devices and nozzles. Recently developed by CANMET, it provides the simplest and most economical approach. This paper describes and compares the three preparation methods, from a practical and an economic point of view. Once the pastefill/high density fill has been prepared and binder added, the backfill must be distributed underground into the stopes. A fundamental factor in the design of a distribution system is the rheology of the material- No two materials will exhibit the same properties, and a sequence of rheological and related testing is required prior to the completion of the design of the underground distribution system. This paper covers the testwork normally required and discusses the fundamental design parameters of pastefill distribution systems. The final section of this paper summarises the use of pastefill at three mincsin Canada.

Jan 1, 1998