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By O Haavisto, N Khajehzadeh, L Koresaar

Online analysis of metal content can be used to optimise the grade and recovery of a flotation circuit. Compared to conventional laboratory analyses, the benefit of an online analyser is the speed of the measurement, therefore disturbances (eg changes in feed grade and decrease in recovery) can be reacted to in real time by an operator or automatic process control system. In some cases traditional X-ray fluorescence analysers can be applied to silica analysis in iron ore when the SiO2 grades are high enough and have a negative correlation with iron; however, generally a laser-induced breakdown spectroscopy (LIBS) analyser is more suitable for low Z elements.The Outotec Courier 8® analyser is a LIBS based analyser able to measure elements starting from lithium (Z = 3), thus being able to measure impurities; eg silica and aluminium directly in iron ore slurries. Besides online elemental analysis, the analyser can be combined with optical measurements for rapid continuous measurement of each sample line. Laboratory testing has also shown potential for mineralogical analysis using the combination of LIBS and reflectance spectroscopy.CITATION:Koresaar, L, Khajehzadeh, N, Haavisto, O and Timperi, J, 2017. Online elemental and mineral measurement of slurries in iron ore beneficiation, in Proceedings Iron Ore 2017, pp 561–566 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

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

Once and for all, the debate on the exponent in Gy's formula is pushed to its limit. It is explained why an exponent of 2.5, obtained when using a square root of nominal size d to adapt the value of a calculated liberation factor to a different comminution size, will rarely be encountered in practice, if no arbitrary decisions are made.

Mar 1, 2010

By F M. Weir, M Fowler

A discrete fracture network (DFN) approach involves numerical modelling that explicitly represents how defects may be spatially distributed through a rock mass. A DFN is a 3D realisation of the ‘smaller scale’, non-deterministic defects; it is not an attempt to model larger, deterministic structures that should be identified as part of an engineering geology model. The approach utilises structural data in stochastic analyses to give a range of possible models that provides a tool for visualisation and analysis of a rock mass and indicates the potential large-scale slope or tunnel performance and stability.Stochastic fracture modelling for rock mass characterisation has significantly advanced over the past 25 years. With recent improvements to field data collection and computational power, it has become recognised internationally as a valuable tool for modelling some geomechanical problems encountered when designing excavations in fractured rock masses.This paper provides an introduction to the DFN approach, particularly the necessary input parameters and derivation of these from typical structural data sources, such as boreholes or scan line mapping. Of particular importance for engineering applications is validation of the simulated fracture network and techniques for doing so are discussed here.CITATION:Weir, F M and Fowler, M, 2014. An introduction to discrete fracture network modelling and its geotechnical applications, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 435–444 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By M Wortley, J McKay, D La Rosa, O Guyo

It has been a generally held concept that crushing operations were, by their nature, too simple to benefit from the implementation of advanced process control. The commissioning of an OCS¬ expert control system and image-based oversize detection system, VisioRock, at the Pilbara Iron Tom Price facility are dispelling these notions. A constraint-based OCS¬ expert control system has been designed and commissioned on the high-grade crushing and screening plant along with a vision-based oversize detection system functioning on six product conveyor belts. To date, the expert control has demonstrated the ability to increase production by maximising dynamic constraint utilisation. Dynamic constraint utilisation is a concept developed by Rio Tinto Technical Services for effectively evaluating constraint-based control logic performance. The VisioRock system has been installed and configured and has been operating for a period of several months. Currently, Tom Price and Metso personnel are working to define correct oversize detection thresholds. Details of the plant implementation are discussed.

Jan 1, 2006

By D François-Bongarçon

The theory of sampling (TOS), and therefore representative sampling, is based on three fundamental principles: sample correctness, which handles the search for non-bias; segregation, the effects of which must be eliminated or minimised; and variance control to help achieve the desired reproducibility. After briefly reviewing these very few, albeit essential first principles of Gy’s TOS, the state-of-the-art in TOS is examined through the prism of these principles and the prospects for the future are explored, with suggestions for further research where relevant. Regarding segregation, which is currently the focus of much research, new orientations are proposed. For correctness, which takes on a major importance when it comes to sampling devices, some new, important principles that have been put forth by recent research, are described in details.CITATION:François-Bongarçon, D, 2014. State of affairs and current research trends in theory of sampling fundamentals, including segregation and correctness, in Proceedings Sampling 2014 , pp 11–16 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 29, 2014

By P González, J Videla, E Córdova, I Gottreux

Currently, underground mining of deeper massive deposits with lower grades, harder rock conditions in high strength environments, entails difficulties in caving, fragmentation and seismicity of the orebody.So far, the use of preconditioning (PC) with hydraulic fracturing (HF) has shown positive results in terms of seismic response and caving performance, while PC combined with explosives aims to weaken the rock mass, causing an additional effect on fragmentation.In particular, mines commonly referred to as ‘supercaves’, operated by caving methods, have the need to integrate mine to plant processes, where rock fragmentation appears as a key tool. In fact, it implies making mining and comminution processes more efficient to the plant and for mines, it justifies the search of innovative solutions in drilling and blasting techniques to precondition the rock mass. The following paper aims to show the feasibility of numerical blast modelling to weaken the rock mass using explosives, mainly through sensitivity analysis applied to designs to minimise bias and uncertainty in the results. It is shown how the presence of structures, their geometry and in situ stresses influence or interfere with the PC method being used.From the work, it is concluded that better knowledge on the application of explosives weakening allows specialists to strengthen numerical models associated with every design and therefore previously validate their applicability, helping to understand complex phenomena such as the propagation of mechanical waves in non-elastic heterogeneous media. In this sense, it is understood that while there are studies (Sanchidrián, Segarra and López, 2006) showing that the transfer of energy in the rock mass could be even greater in a confined environment, the more competent rock mass and higher in situ stresses interfere mostly on the effectiveness of a technique using explosives.CITATION:Gottreux, I, Córdova, E, González, P and Videla, J, 2016. Preconditioning modelling and explosives effectiveness in block caving, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 683–688 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

This paper is an outline of the developmental practices now in use at North Broken Hill Limited, N.S.W. The description will be given under the following headings.I. General.......opening up of a new level.II. Driving.III. Winzing.IV. Rising.V. Auxiliary Ventilation.VI. Notes on the Introduction of Mechanical Appliances.VII. Office Records and Routine.I. GENERALThe lode, for purposes of description, may be said to be divided into two portions which are usually referred to as the Southern and Northern Orebodies.The southern ore-body is the larger and in places attains a width of 200 feet. The northern ore-body is, generally speaking, comparatively narrow. These ore-bodies have a northerly pitch of approximately 45' and a westerly dip of 60. In the southern ore-body a grid of ore chutes is provided at 31 ft. 8 in. (5 square set) intervals and this necessitates an elaborate arrangement of cross-cuts, portion of which have to be driven through the foot-wall. Crushed country rock adjacent to the foot-wall makes it necessary for drives to be placed at least 60 feet from the lode.In the northern ore-body the ore chutes are arranged along a longitudinal drive, thus making a much simpler layout. These layouts were described in detail by A. R. West (Proceedings A.I.M.M. No. 117). In opening up a new level from the shaft plat, a heading is extended in a westerly direction until a point approximately 60 feet from the footwall of the lode is reached.At this point the direction of the cross-cut is altered to a bearing approximately 90 to the general strike of the ore-body, and the cross-cut continued until the hanging-wall is intersected. From the information obtained together with that from diamond drilling, the outline of the ore-body is plotted as closely as possible, and this serves as a basis for the layout of the level. Drives south and north from the main cross-cut are made in order to determine the southern and northern extremity of the southern ore-body. The former is usually driven in the centre of the ore-body and serves as a permanent gangway and ventilation drive for the new level.From the northern extremity of the southern ore-body, the drive north is...

Jan 1, 1944

By D J. Hill

"Mining companies routinely invest in improvements to their processing operations, but often these enhancements do not work to full effect.Improvements can be ineffectual because underlying process problems are not identified or prioritised for correction or repair.This is frequently because ‘black box’ solutions deployed to implement process control improvements typically rely on instrumentation to provide data for algorithms to work effectively, and these solutions are often ineffective or disabled at mineral processing sites.There are three key reasons they can fail to deliver: vital instrumentation is not calibrated or functioning as required basic process control and loop tuning was not implemented correctly or is in need of tuning there is an inability to support the ‘black box’ solutions on-site.Many of these problems can be overcome by implementing operational analytics that identify where problems are occurring and prioritise where improvements need to be made.Incorporating operational analytics into process improvement is not a new methodology. It is more a back-to-basics approach to make more efficient use of capital and systems already deployed.Data collection systems, such as the OSIsoft PI System, provide real-time and historical process information for process control experts to analyse and identify areas for improvement. However, most systems are not used effectively. With some simple enabling, data collection systems can provide evidence for prioritising investments in improvements and determining an investment’s effectiveness.MIPAC advocates that the initial step, with analytical evidence, is that clients review the control strategies and implement small influential instrument repairs/calibrations and operator training. This can significantly boost process productivity without the need to spend large sums of money on new capital or employing expensive, difficult to maintain ‘black box’ solutions.A simple Stage-Gate®-style approach ensures that small investments in evidence-based process improvements deliver significant benefits to mining operations.CITATION:Hill, D J, 2014. How to prioritise process improvements, in Proceedings 12th AusIMM Mill Operators’ Conference 2014, pp 307–314 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 1, 2014

The distribution of tin and iron between slag and metal phases at about 1150°C was studied in pot scale experiments. The distribution coefficient k = (Sn/Fe) In metal X (Fe/Sn) in slag was found to vary from about 300 for metal corresponding to nearly pure tin, to about 100 for metal of about miscibility gap composition (17' 4 per cent Fe). Results conformed reasonably well to a straight line relationship between log k and (l-2NFe), as expected on theoretical grounds, and are consistent with thermodynamic data for the Fe-Sn phase diagram and the reaction Fe + SnO = FeO + Sn.Calculations are presented indicating the feasibility of smelting low-grade tin concentrates in a two-stage counter-current reduction process.

Jan 1, 1966

By A Hamanaka

EGAT Mae Moh Lignite Mine in Thailand produces about 16 Mt of lignite annually from open-cut mining. The coal is used to generate 2400 MW of electricity. In the near future, however, the coal must be extracted from underground at 400 - 500 m deep from the surface. The problem is the thickness of the coal seams. There are two coal seams that are about 25 m thick with 20 - 25 m of interburden between them.In order to investigate thick seam mining systems and propose a new mining system in ultra-thick coal seams in Thailand, a joint research group was established by Japanese and Thai researchers and mining engineers in early 2009. This paper describes conventional underground mining systems and underground coal gasification for thick coal seams and discusses the applicable coal mining systems to this mine. Then, this paper proposes an innovative underground coal mining system for thick coal seam, ‘eco-friendly underground coal mining system which consists of the utilisation of flyash and CO2 storage’.

Nov 22, 2011

By T Trott, M Lewis, G Lumley

The analysis of equipment trends in The AusIMMÆs revision of Monograph 19 - Australasian Mining and Metallurgical Operating Practices (AMMOP) (in prep) in the paper by Graham Lumley raised some interesting, and in parts disturbing, trends in the Australian open cut mining industry. According to the Australian Bureau of Statistics (2011) the productivity of the whole mining industry is down by 34 per cent since 2001. In terms of open cut equipment, median output for draglines is down by 15 per cent since 2003, electric rope shovels are down by 41 per cent since 2003, hydraulic excavators are down by 39 per cent since 2008, front-end loaders are down by 39 per cent since 2007 and trucks are down by 41 per cent since 2006. Clearly e boom has not been good for the efficiency of the mines. During this same time, best practice (defined as the average of the top ten per cent by annual output per unit of input) has declined, but not by as much as the median (eg shovels down by eight per cent, excavators down by 19 per cent and FELs down by five per cent). This paper will build on the analysis of AMMOP to understand the differences occurring between median and best practice and identify the factors contributing to the decline in performance. As the industry enters a period of potentially lower prices for commodities and reduced margins, pressure will be brought to bear on mine sites to start moving more with the equipment they have. An understanding of where efficiency has been lost will be a key component in that. The information contained in AMMOP, and the subsequent analysis of that information in papers such as this one, will be crucial to reversing the decline in open cut equipment performance.CITATION:Lumley, G, Trott, T and Lewis, M, 2012. Reversing the trend in open pit mining equipment output, in Proceedings Eighth Open Pit OperatorsÆ Conference , pp 75-82 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 18, 2012

By Y Ren

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Aug 12, 2013

By J Shandro

This paper stems from recent multidisciplinary research between mining engineering and health researchers at the University of British Columbia and the University of Victoria, Canada. It considers the implications of a future state of sustainable mining development that places more emphasis on consideration of mine community health and sustainability within the definition of mine planning best practice. It reviews recently completed research studies on mining and other resource communities in British Columbia, Canada and a process undertaken by the research team to share research findings. It then examines the outcomes of this knowledge sharing process placing emphasis on the development of a more collaborative and enhanced mine planning process that integrates community- level indicators of health and sustainability to more effectively address mine impact-benefits. The paper concludes by discussing current initiatives that aim to benefit the mining industry, communities, and governments as they plan future mineral development projects.

Nov 22, 2011

By Brotzmann K, Turner RE, Philp DK, Rusden RC

New approaches in the last decade have led to the supplemental use of raw coal as a direct energy source in several iron and steelmaking processes. The dependence on more expensive coke and electricity is being progressively reduced. The Technology Venture of Klockner Werke and CRA has pionered several of these developments and is pushing ahead to processes for scrap melting and direct smel- ting of iron where coal is the ONLY energy source. Such complex developments depend strong- ly on the experience gained in the simpler but related processes for coal use already in operation. The longer term implications of a successful coal-based direct smelting process for the world steel industry are substantial.

Jan 1, 1986

By Peeler P. K

The recent renewal of interest in hydrometallurgical routes for copper production has been brought about by the possible future reliance on mixed ores and lower grade deposits, environmental aspects, and energy considerations.A number of hydrometallurgical processes for the recovery of copper have recently been proposed. Flowsheets are developed for two processes which incorporate several treatment methods being experimentally studied in Australia.In the first process a cupric chloride leach is followed by electrowinning whilst the second is based on the formation of cuprous ions, stabuized by acetonitrile and subsequent disproportionation to cupric ions and metallic copper. For the purpose of comparison, flowsheets were also developed for the Arbiter and Cymet processes.Process economics are estimated for the four processes and the results are discussed in relation to competitive pyrometallurgy. None of the four hydrometallurgical processes, with possible exception of the Cymet process, appears to be competitive with established large scale and newly developed pyrometallurgical processes for chalcopyrite.However, because the economics of the individual hydrometallurgical processes depend strongly on specific conditions, a "tailored" process may be competitive with pyrometallurgy in particular circumstances.

Jan 1, 1977

By T N. Little

The grade control process undertaken at mines aims to maximise the value of the ore (valuable product) mined and fed downstream for processing or sale. The full range of grade control activities includes: reserve estimating, drilling/sampling, assaying, modelling, ore block design, blasting, ore mark out, excavating, stockpiling, processing and reconciling. Over the last 25 years, the grade control process has undergone significant improvements and this is in part due to the developments in grade control blasting. This paper discusses the development and classification of grade control blasting applications in surface mining. A review by the author in 1988 (Little and van Rooyen, 1988) is used as a benchmark for discussing the very significant progress that has been made.Two major technology initiatives have enabled this development. The first was the development of a method for the measurement and analysis of total displacement during the blasting process. Currently, the Blast Movement Monitor (BMM®) is a practical tool that has been used around the world to improve the industry’s understanding of three-dimensional blast movement dynamics. The second technological enabler was the development of electronic detonator systems. The unique aspects of electronic detonating systems are their higher accuracy and that all detonators are activated at time zero (initiation). From a grade control blasting perspective these features and other improvements allow experimentation and, ultimately, more complex, multiobjective blasts to be designed and implemented.This paper reports on a classification and review study undertaken by the author. In all, five selective blasting methods and nine bulk blasting methods are classified and reviewed. Five important observations are made: there is value in classifying the range of grade control blasting strategies, and the blasting objective framework presented is helpful in this regard the range of strategies available to designers is increasing as enabling technology develops, so too do the ambitions of blast designers and the expectations of downstream customersgrade control blasting and Mine to Mill concepts are merging, and this paper caters for this trend using multiple blasting objectiveshaving a technical primary blasting objectives framework, combined with the classification system presented here, should assist practitioners and stakeholders with lateral thinking in regards to future technological innovations, grade control blasting and Mine to Mill initiatives.CITATION:Little, T N, 2015. Classification and development in grade control blasting for surface mines, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 343–354 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

This paper presents the near-field rock damage owing to production blasting in limestone quarry in the western region of Japan. The study's purpose is to learn the mechanism of crack development due to blast vibration. In this study, blast vibration's magnitude was expressed with peak particle velocity (PPV) which was obtained based on seismographs recorded database. In attempt to pursue a research's purpose of this study, there were two considerable interests: near-field blast vibration propagation and prediction, and crack observed and prediction. Furthermore, with regards to considerable interest of the study, there were three essential aspects which were challenged, such as: monitoring and interpretation of seismic wave propagation in a rock mass near large explosive charge of production blast scale, measurement of blast rock damage in adjacent to blasthole, and determine critical value of PPV which may produce significant rock damage. In order to determine precision critical PPV, understanding correlation between rock damage with vibration level is firstly important to be done. This paper also discusses how to measure, detect and quantify near-field blast vibration and blast rock damage in adjacent to blasthole.

Dec 6, 2010

By G R. Ballantyne, A N. Mainza, M S. Powell, M Evertsson

Quantifying the performance of a comminution circuit relative to the potential that can be achieved is a standard requirement in justifying operating practice (the stick) and seeking operational upside (the carrot). Historic measures tend to focus on performance relative to laboratory design tests that provide a direct measure of specific grinding energy, such as the Bond Work index; or use dropweight breakage tests calibrated to a substantial database of operating sites, such as the SMC methodology. Although of value, such approaches are flawed in significant aspects. The assumption is that the laboratory prediction is correct and the single sample it is based on is representative. The database benchmarking methods are, by definition, locked into current average operating practice. These approaches do not illuminate upside; can ‘punish’ operations that are actually more efficient, such as grinding finer than standard operation; and reward poor operation that may comfortably produce a coarser grind than optimal for recovery or excess slimes that reduce recovery and increase water consumption and tailings volume. The authors present a set of established and easily applied measures, that draw together daily operation, highlight areas of opportunity and inefficiency, use simple samples and data, and can be used to provide the ‘size of the prize’ in pursuing specific areas of process improvement. These tools include size specific energy (SSE), overall operating effectiveness (OEE) which includes product quality, theory of constraints, and links this to the end objective – maximising the efficient production of valuable metals. Feeds into objective function driven by economics – financial return, energy, environment.

Aug 24, 2022

Shane is enjoying his new work. Six months ago, he was stocking shelves at his local supermarket and decided to make the big move to a job in mining with more challenge and, of course, more dollars. He's been through his inductions, received his training tickets and is now working in a crew of eight underground at a fly-in, fly-out (FIFO) operation. There are many more systems and processes here than in his retail job, and Shane's comfortable that his safety is being looked after. He is enjoying the continually changing work and conditions, it makes the job interesting. It's taking some time to get used to the roster and he is worn out by changeover, but he gets more time with friends and family during R & R.   Generally, the mining industry has a maturing safety culture and well developed systems. This sometimes lulls people into a false sense of security. Safety systems cannot anticipate every possible situation, nor can they replace people's perception, thinking and decision-making. To manage safety, it's critical to find the right balance between dependence on systems and a healthy fear and respect of risks we face.   As safety standards are raised, systems tend to get more thorough and complex. When a new person joins a mining crew, we induct and train them to provide the information they need. As labour availability again becomes short, and many new people join our industry, we shouldn't assume they know the fundamentals. We need to explain not only what they are expected to do, but why doing what we ask and expect will keep them safe. We must equip people to deal with both the routine and the unexpected.   This presentation explores the challenges of balancing a structured, systematic approach to safety with the need to also equip people to deal effectively with risks everyday in dynamic and extraordinary situations.   Session purpose Introduce participants to a way of looking at risk from a different perspective, as a force for change and progress, if managed well. Demonstrate that risk is something we need to engage with emotionally as well as physically, if we want our risk management efforts to be successful. This purpose will be achieved through an entertaining and engaging presentation, using photos and case studies. The session will initiate interest to explore new ways of thinking about risk and generate discussion about the balance between people and systems. What is the right balance and why getting it right enhances the safety culture, while getting it wrong can impact on safety, business performance and sustainability.

Jun 1, 2010