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Coal exploration and mine planning now use all the modem techniques to indicate geological hazards to a new or developing coal mine. Drilling, seismic and other sophisticated geophysical methods aim to increase the reliability of prediction of features which will inhibit mine development. But do they?. During the past 40 years, geological investigations for coal mines in New South Wales have ranged from the general observations of Eric Rudd, in the Southern Coalfield in the late 1940s to the very detailed examinations of roof strata by John Shepherd and others in the 1980s. Then, the large scale regional relationships between sedimentary and structural features often were ignored as the minute examination of seam roof strata became fashionable.

Jan 1, 1991

By D O’Dea, B Godel, T Honeyands, B Ellis, T Harvey

X-ray computed tomography (XCT) is a non-destructive technique that allows the exploration of the internal structure of solid objects in 3D. Over the past ten years, the combination of XCT with more conventional 2D techniques and quantitative 3D image processing and analysis (commonly referred to as digital rocks) has allowed us to address some of the most challenging problems in ore deposit studies. The range of X-ray energies used in XCT allows the X-rays to be transmitted through complex and dense materials including iron ores (eg sinters, lumps, granules). Recent high-resolution XCT scanners have the ability to generate multiscale (25 down to 0.3 µm voxel size) imaging of a given sample enabling the characterisation of 3D textures across a range of scales. This paper will focus on the application of digital rocks to iron ore sinter particles (using filtered polychromatic X-ray beam). The paper is divided into three parts and includes: i) details on the methodologies including their benefits and limitations and the effect of spatial resolution; (ii) the quantification of pore network topology and pore characteristics (eg open versus closed pores, pore size distribution and pore morphologies; degree of connectivity of the pore network and its tortuosity); and (iii) the evaluation of the technique to characterise various phases within the material and quantify 3D mineral textures.CITATION:Godel, B, Ellis, B, O’Dea, D, Honeyands, T and Harvey, T, 2017. Digital rocks for iron ore sinters – towards a D quantification of sinter textures, in Proceedings Iron Ore 2017, pp 529–534 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By A Radici, S Russell

The Dampier Port Upgrade was completed in 2007 and is the largest project in Rio Tinto Iron Ore's expansion program. The project doubled Dampier Port's iron ore shipping capacity over a five year period. Sinclair Knight Merz (SKM) was appointed by Rio Tinto as the Engineering, Procurement and Construction Management (EPCM) contractor to manage Phase A and Phase B of the Dampier Port Upgrade. The aim of the project was to increase the Dampier Port capacity from 74 to 140 million tonnes per annum (Mt/a). This increase in shipping capacity tripled the capacity of the Parker Point facility from 34 to 94 Mt/a, whilst the East Intercourse Island facility increased from 40 to 46 Mt/a. The Dampier port remained fully operational throughout construction and achieved record yearly export tonnages over the period of the project. The $US1.4B project was completed ahead of schedule, on budget and with an outstanding safety record. Significantly the project team set an industry benchmark by achieving five million man-hours Lost Time Injury (LTI) free. The project has been recognised by the Engineers Australia 2008 Western Australian Engineering Excellence awards as category winner in resources and the overall winner in WA, and went on to win a National Engineering Excellence award. This paper provides an overview of the EPCM project management and an insight into some of the key drivers that have delivered this outstanding project.

Jan 1, 2009

By M P. Schwarz

A major issue presently faced by companies producing and processing iron ore is the need to maximise throughput while minimising capital expenditure. While present high demand means this is of prime importance, the perennial issues of maintenance, operating costs, reliability, quality and environmental sustainability are also critical to profi tability. Attempts to address these issues generally require modifi cations to existing equipment, or trials of new equipment when designing plant for new projects.The risk involved can be substantially minimised by testing equipment improvements using advanced computational models prior to implementation. Examples of application of Computational Fluid Dynamics (CFD) and Discrete Element Method (DEM) modelling to sampling, cyclones, conveyor transfers, classifiers, dust control, banana screens, comminution and smelt-reduction will be given to illustrate the benefi ts of such an approach. *This is an abstract only. No paper was provided for this abstract.*

Jul 11, 2011

By S Udayakumar, S Biswal, N Sarmadi, V Sahajwalla, F Pahlevani

Recent times have witnessed a notable momentum in the interest surrounding technology dedicated to harnessing waste as valuable resources, prompted by the mounting challenges posed by waste accumulation and the swift depletion of natural resources. The carbon dissolution process within a molten iron bath stands as a pivotal reaction within the metal processing sector. The current study explores the utilisation of waste graphite electrodes (WGE) (obtained after being utilised in an electric arc furnace) as a secondary resource of carbon for dissolution into liquid iron. Experimental investigations were carried out at 1550°C using the sessile drop approach. High purity iron powder was used and the carbonaceous substrates were prepared from the ground WGE. The carbon pickup was determined using a suitable carbon analyser. Furthermore, an examination of the interfacial area between the molten iron and the WGE substrate was conducted beneath the metallic droplet, which effectively represents the iron/carbon interface. This interfacial analysis was carried out on two different samples obtained after a varying period of heat treatments at 1550°C. The interface layer was investigated using scanning electron microscopy (SEM) in conjunction with energy-dispersive X-ray spectroscopy (EDS).

Jun 19, 2024

By C J. Kruger, E le Roux

Anglo American Platinum has adopted a strategy of Best Practice Principles (BPP) for sampling, mass measurement, analysis and metal accounting for more than a decade now. When new plants are designed, the most suitable sampling equipment and sampling protocols are implemented and material flows and plant layouts are designed around sampling strategies. A few years ago, a crushing plant for a high-grade matte stream was commissioned.The design called for the high-grade material to be crushed to 95 per cent passing 2 mm and the design allowed for a single cutter primary Vezin sampler, increments taken from a gravity flowing stream at regular intervals, whilst filling a tanker for the pneumatic offload at our base metal refinery. This was a single point of sampling and analysis that would measure the wanted output from our smelting complex and the input to our refineries. In addition, the design incorporated the functionality to collect increments in an ‘interleaved’ fashion from the Vezin sampler for internal precision checks.The metal accounting strategy for Anglo Platinum is the ongoing measurement of all inputs, outputs and stock levels for all our operations for platinum group metal (PGM) and base metal (BM) content. Included are yearly stocktakes, usually done on 1 February every year, across the smelters and refineries (at least the base metal refinery). A trend was developing in the accounting period immediately following the introduction of the new crushing and sampling facility, whereby the absolute difference between the physical stock and theoretical stock (PGMs predominantly) increased for the two respective sites on an ongoing basis. The smelter (sender) showed an increase in physical stock compared to the theoretical stock and the base metal refinery (receiver) showed that their theoretical stock increased against their physical stock. Because of this anomaly, an additional stocktake was held in September for the period in question and it was confirmed through the physical stock measurement results, that the PGM accounting problem was indeed pointing towards the evaluation of the high-grade matte stream.This paper showcases parts of the process that took place to explain the poor accountabilities for the respective sites. Previous results from the sampler ratification process (of the interleaved sampling design) were analysed again, a physical inspection was carried out on the sampling system again and the sampler performance was monitored (quality control parameters) for the period.From these investigations, it was found that airflows present inside the Vezin introduced the sampling bias and a change in sampling protocol was introduced as well as physical changes to the sampling equipment were made to eliminate the airflow and thus the bias conditions significantly. The accounting period which followed, after a phased upgrading process, showed that the accounting between our smelter and base metal refinery had been restored to within statistical limits (difference between physical and theoretical stock below five per cent relative to theoretical stock).CITATION:Kruger, C J and le Roux, E, 2017. Pitfalls in Vezin sampling for finely crushed materials, in Proceedings Eighth World Conference on Sampling and Blending , pp 151–158 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By Hemingway J, Read T. A, Anderson V. G

IN the determination of very small amounts of lead, the usual analytical methods are far from being satisfactory. Small amounts of lead may be present in the reagents empioyed, and it is customary to run a blank experiment to correct the error arising in this way. When the correction is of small magnitude compared with the amount of lead in the sample, this procedure may be adopted; but when very small amounts of lead are being determined it may happen that the lead found in the blank is as much, or even more, than the lead actually present in the sample, and the analysis has to be rejected. Moreover, the blank experiment cannot check errors which are not common to the blank and the analysis itself eg, the apparatus used in the parallel experiments, etc. It seemed to be desirable, tl;l.erefore, to make an investigation of the problem to ascertain, as far as possible, the nature of the errors arising from the introduction or loss of lead during the analysis, and how far these could be eliminated or corrected for; also, to determine the limits of accuracy of the improved method and the minimum amount of lead that could be reliably estimated.In the investigation, reliability and sensitiveness were regarded as essential features. Speed of operation, on the other hand, was considered of less importance. The amounts of lead dealt with being usually less than 1 mg, there is no alternative to the use of a colorimetric method. The latter, depending as it does upon the development of a brown coloration when ammonium sulphide is added to a very dilute -solution of a lead salt, is far from being a characteristic test for lead. Indeed, it is well known that the salts of most of the commonly occurring metals interfere with this test. Hence it is of vital importance that the lead should be isolated in the form of a pure compound possessing quite definite and characteristic properties before the colorimetric estimation is proceeded with...

Jan 1, 1921

By Wood W, Bell A

Brown coal production in Victoria's Latrobe Valley Region (Figure 1) continues to rise and currently stands at around 50 Mt per annum. With the exception of around 2 Mt used to produce some 700 Kt of brown coal briquettes, this coal is mined by the State Electricity Commission to fuel large thermal power stations with a total installed capacity of just over 5 000 Megawatts. The moisture content of the coal as mined typically exceeds 60 per cent, making Latrobe Valley coal a markedly low rank fuel. The lack of heating value is, however, compensated for through power station design and by the fact that ash yield is very low, usually within the range of one per cent to four per cent on a dry basis. This means that compared with most other coals, the burning of Latrobe Valley brown coal produces relatively small quantities of waste products and discharges a minimal level of pollutants into the atmosphere. Even so, the inherent quality of Latrobe Valley coal does vary significantly from one area to another (Gloe, 1991; Barton et al, 1992) both on a local and a regional scale. Such variations need to be recognised and understood in order to not only realise efficiency gains in existing power stations but to properly assess resource potential for future utilisation and the application of new technologies. The principal aim of this paper is not to describe coal quality variation in detail or to speculate on the nature of and reasons for such variation. Rather, it is to simply underscore that significant differences do occur and that this is clearly a factor which needs to be considered in any evaluation of Latrobe Valley brown coal as a resource for the future.

Jan 1, 1992

By D Reid

The engineering properties of soils and tailings often exhibit significant anisotropy. One area where this has been well documents is undrained shear strength. Materials sheared in directions close to the principal stress direction in situ, i.e. triaxial compression, typically exhibit higher undrained strengths than those sheared in other directions such as simple shear. Importantly, along the most common critical failure surfaces relevant to tailings stability, whether primarily through tailings or a critical foundation layer, saturated materials are generally much closer to the simple shear loading direction than triaxial compression. Therefore, testing undrained shear strength of tailings or foundation soils in triaxial compression is likely to result in overestimation of the relevant strengths for design. Although these issues have repeatedly documented in the geotechnical literature for over three decades, they are not appreciated sufficiently across our industry. In an attempt to address and highlight these issues, a review is carried out of historical reference to the importance of simple shear loading. Attention is then drawn to the techniques applied in three recent post-failure investigations, where simple shear testing was applied. Finally, some relevant laboratory test results from a recent project in which the author was involved are outlined.CITATION:Reid, D, 2018. Importance of the simple shear loading direction to the stability of tailings storage facilities, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 274–284 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

The society in which we live is one of change, and we professionals are part of that society. The importance of this simple and obvious statement is often overlooked. My Presidential Address examines the question: can professionalism survive in our changing society?There is ample evidence to show that our society is changing, and that the rate of change is exponential. This rapid and accelerating rate of change is what Alvin Tomer refers to as "future shock". Rapid change means that we do not have time to become accustomed to what is happening around us and to feel comfortable with it; the greater the rate of change the greater the discomfort. The effect that this has on people is varied; the change may be either expected or totally unexpected.The rate and extent of change in society is not the same for all countries nor for all industries or occupations. Change is more rapid in Japan, Korea or Taiwan, than in Australia. It is more rapid in our cities than in the bush, more rapid for professional businessmen than for farmers. In our minerals and petroleum industries, we are still adjusting to the great changes that have taken place over the last fifteen years. In the past, products from our industries were sold on a free and open market. Today, mineral development and production in most undeveloped countries and some developed countries is manipulated for political, social and economic reasons. Changes of this nature have had a devastating effect on the operations of established mineral producers in the democracies.Because of the accelerating nature of change, we must recognise that the past is not a reliable guide to the future.Although extrapolation of the past into the future is a basic ingredient of commercial survival, extrapolation is less and less reliable.I borrow from others in quoting the Irish proverb: "The future is not what it was".The future is where our business lies and most of us at this Conference must endeavour to understand it and adjust to it. I believe in the old adage that:You can't know where you're going if you don't know where you've been and where you are at.There are a number of major factors which have created change within our social, economic, and industrial environment in recent years.

Jan 1, 1985

By Jiang G

The Chinese Central Government attaches great importance to the development of its coal industry. Besides carrying out the policy of simultaneous development of large, medium and small coalmines,the main strategy is to gradually modernize coal mining areas and coalmines and to increase the output from individual coalfaces. There are particular implications, processes and main experiences of coalmine modernisation in China.Ensuring a coal output of over one M tonne/yr from one coalface is a very complicated system-engineering project which deals with a wide range of problems. The most important measure used for achieving an output of over one M tonne/yr from a single coalface is the analysis of affecting factors on coalface production by means of the theory c reliability. Thus, as far as possible , the production stoppages caused by mechanical equipment failures and other factors are avoided, the equipment recovery rate is increased and the working hours of shearers are extended so as to ensure a high output and high efficiency.

Jan 1, 1991

By L Barrere, J P. Sykes, A Trench, R S. Davies

Western Australia (WA), alongside Brazil, has remained at the forefront of the global seaborne traded iron ore market for over 40 years. Despite this apparent stability and strong market position, WA continues to face strong external international supply-side competition, mainly from Brazil, but also periodically from often marginal, non-traditional sources of iron ore. Additionally, WA iron ore supply has undergone significant decadal change internally, both of an evolutionary (brownfields expansion) and revolutionary nature (major new greenfields projects). Since 2006, a new generation of WA-focused iron ore explorers, developers and producers have emerged.The majors, BHP Billiton and Rio Tinto, have expanded mine production to record levels and the Roy Hill project is now approaching nameplate capacity. Fortescue Metals Group (FMG) is, however, the largest new market entrant of the last decade, delivering upon their vision of becoming the ‘new force in iron ore’. Unlike most of the other new WA market entrants, FMG’s operations are substantive. Most of the other smaller, new WA iron ore miners have struggled during the period of falling prices, though it is worth noting that collectively they have made a material supply-side impact during the price boom – typical of marginal supply. Finally there have been some contributions from new magnetite projects, however, the delivery and economics of these projects have not met expectations.In this paper, we touch briefly upon the key global market changes of the last decade, namely China-driven demand growth and the changes to the pricing mechanisms for iron ores – before reviewing the rise in WA iron ore supply in response to these markets. We finish by focusing on the most significant WA-focused supply-side development of the last decade, the rise of FMG as a major new supplier and the strategic situation that facilitated its rise. The unprecedented China-led rise in iron ore prices felled many traditional barriers to market entry into an oligopolistic industry, allowing many new market entrants (in WA and around the world). However, the downturn in iron ore prices resurrected these barriers to entry, with only FMG (thus far) breaking the entry barrier with significant scale. Difficult corporate decisions have been forced upon the smaller WA iron ore miners who, in some cases, will now struggle to further expand, or indeed continue to operate in the longer run.The changes that have taken place over the last decade of WA iron ore production hold insights for other emergent mineral commodity exports from the state. Successful market entry, even when industry barriers are high, does not always require an immediate low-cost production assumption alongside a strong balance sheet. FMG could see a new market, within an established commodity market, target an appropriate and new product at it, overcome temporarily-felled barriers to entry in infrastructure and finance, then innovate and aggressively cut costs ensuring it was behind the barriers to entry when they rose again after the price boom.CITATION:Barrere, L, Trench, A, Sykes, J P and Davies, R S, 2017. New generation Western Australian iron ore – strategic insights far beyond the Pilbara?, in Proceedings Iron Ore 2017, pp 375–386 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

The United StatesÆ reporting standard for the mining industry for securities purposes is contained in the Security and Exchange CommissionÆs Industry Guide 7. It defines proven and probable Reserves using its own definitions, and prohibits the disclosure of quantitative estimates, for all mineralisation other than those two Reserve categories (though disclosure of Measured and Indicated Resources as quantitative mineralised material estimates is now informally allowed). Similarly, it restricts disclosure of value estimates to Reserves only, which SEC policy generally requires to be on an historic cost accounting basis. The SEC does not maintain a formal Competent or Qualified Person policy. In March 1999, the US-based Society of Mining, Metallurgy and Exploration (SME) released an update of its 1991 guidelines for definitions to be used in reporting of Mineral Resources, Reserves and Exploration Information, closely abiding by the 1997 CMMI recommendations. However, without SEC recognition, reporting under the SME and CMMI definitions is effectively barred for US companies. The SEC intends to adopt the International Financial Reporting Standards (IFRS) of the International Accounting Standards Board (IASB). This will occur within just a few years, when the convergence project for development of the IFRS has reached a satisfactory point. The US is the largest financial supporter and participator in IASB. The Extractive Industries Standard of the IFRS will likely terminate Industry Guide 7. However, the effect of this international replacement will likely be equally restrictive. This could possibly neutralise the benefit of a CMMI-based global reporting standard. SME, the US society encompassing the widest range of mining industry professionals, does not have a Code of Ethics. It has no mechanism for requiring members to abide by a professional standard. SME is presently looking into possible solutions for this deficiency. US-based professional societies that do have a binding Code of Ethics, generally cater to a single profession, and are not just mining industry related. The American Institute of Professional Geologists (AIPG) and the American Institute of Minerals Appraisers (AIMA) are examples. The SME is considering creating a subsidiary body with an enforceable Code of Ethics. To support a CMMI-based global reporting standard, competent persons will need to work across international borders. A standardised mechanism for qualifying and registering competent persons will be needed. National rules and laws must allow competent persons to easily enter countries to perform their work. State issued licenses are increasingly required for much of the work performed in the US mining industry by engineers, geologists and minerals appraisers (valuers). Such licenses are not required by the SEC for Reserve reporting in the US, may not be required for valuation of mineral properties under certain circumstances, and except for real property valuer licenses, they generally do not have a binding code of conduct. However, state licensing of professionals forms a substantial and increasing barrier to interstate trade in professional services, and can be a prohibitive barrier to professionals from outside the US. Any rationalisation of this confusing patchwork of regulations confronting US minerals industry practitioners will only occur as part of larger, national change, hopefully aimed at compliance with international standards and protocols. The US does not have a valuation standard aimed specifically at the mining industry. The Uniform Standards of Professional Appraisal Practice, the national valuation standards, often must be applied to mineral property valuation, but contains no specific instructions for minerals. The author has campaigned against development of minerals valuation standards proposed by US minerals institutes. Instead he encourages the mining industry worldwide to place its support behind the initiative of the International Valuation Standards Committee (IVSC) to include an extractive industries section in its International Valuation Standards (IVS). This should provide a global set of valuation standards for the mining and petroleum industry within two years. This addition to IVS will provide essential valuation standards reference support for the extractive industries financial reporting standard of the International Accounting Standards Board. The IVS has achieved a high level of acceptance in the developed and lesser developed countries of the world. It provides a comprehensive framework of Generally Accepted Valuation Principles for the valuation profession internationally, for valuation of all property or asset types. IVSC is effectively a sister organisation to IASB. The IASBÆs International Financial Reporting Standards (IFRS), previously known as the International Accounting Standards (IAS), reference and quote IVS in some instructions for determination of fair value. IVSC is a non-governmental organisation (NGO) member of the United Nations and maintains liaison with many important international economic, accounting and financial agencies, such as the OECD, IMF and WTO.

Jan 1, 2002

The Middleback Ranges are a series of parallel northsouth ridges on the eastern side of the Eyre Peninsula, South Australia, about 20 miles inland from the Spencer Gulf, as shown in Fig. 1. They extend for some 20 miles across the centre of the County of York. North of them, on the same line of strike, in, the County of Manchester, is a disconnected series of lesser which ends in the Iron Monarch-Iron Knob ridge, the principal iron ore locality. These ridges are referred to in the following pages as an integral part of the Middleback Ranges.The deposits of hematite which outcrop in these ranges (Fig. 1) form the most important group of iron ore bodies in Australia, and are exploited by the Broken Hill Proprietary Company. The largest of them is the Iron Monarch (Fig. 6) .H: The next largest are the Iron Duke, the Iron Prince and Iron Baron. The Iron Knob, Iron Duchess, the North and South Iron Knights, Iron Queen, and the small body south of it, the Kimba Lease, and the deposits in the Cook's and Ash Leases, are all smaller.Numerous small lens-like bodies of hematite occur throughout the ridges, but are not of sufficient size to be of commercial use. At present only the Iron Monarch and the Iron Prince bodies are being worked. The Iron Knob was quarried previously, but its remaining supply is held in reserve.*Published by permission of the Council for Scientific and Industrial Research.

Jan 1, 1936

By S J. Hawke, L A. Dominguez

In non-ferrous metal mining operations, it is generally necessary to crush and grind the ore to a very fine particle size to effectively liberate the contained mineral from the host rock. Fragmentation by blasting is the first stage of this comminution process.Numerous studies and independent modelling of the Mine to Mill process have demonstrated the potential for significant downstream productivity improvements from improved blast fragmentation. However, safety and environmental constraints associated with the blasting process usually limit the extent to which blast energy or powder factor can be increased.An effective blasting solution has been identified that enables the safe utilisation of powder factors several times higher than those used conventionally to provide significant improvements in fragmentation. The solution uses a static ‘blanket’ of broken rock overlying the blast to contain this increased blast energy and control rock movement. To produce this broken layer of rock, the subdrill in each blast is significantly increased to preblast (or precondition) the entire stemming region of subsequent blasts on the next mining bench.The solution has been evaluated at a large open cut poly-metallic mine in Mexico. Results from the application of this technique have shown significant improvement in run-of-mine fragmentation, with subsequent downstream productivity improvement indicated.CITATION:Hawke, S J and Dominguez, L A, 2015. A simple technique for using high energy in blasting, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 321–326 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

This talk was delivered in Kalgoorlie in April this year, to the Kalgoorlie Branch of The Institution of Engineers, Australia. We believe it is of such interest to members of our Institute and readers of this publication we believe it important to extend the audience who have the opportunity to read it. An edited version follows:"Why should we be so concerned about Mining Related Education; after all is said and done, the mining industry is not a great employer of persons?"The mining industry is capital rather than labour intensive. It employs only 2.7 per cent of the national workforce. However; the minerals industry is Australia's major exporter accounting for over 40 per cent of the nation's total export of goods.In Western Australia the value of minerals production in 1985 was about $5,000 million and consequently mineral exports accounted for about 53 per cent of the total value of overseas exports from the State. The diversity of the mining industry is also worthy of mention and produces iron ore, alumina, gold, nickel and mineral sands. That apart, our potential to become a major producer of diamonds, rare earths and petroleum products is considerable, not to mention base metals (copper, lead and zinc) and uranium.Our mining industry is of national importance and contributes in excess of 30 per cent of the total value of Australian overseas trade. Although the mining ind ustry does not employ many people, the people it employs contribute very much more, per capita, to the wealth of the nation than do employees in any other sector of our economy.No-one would deny that during the 20th century Australians have depended on the export earnings from the sale of relatively unprocessed agricultural products and more recently the sale of relatively unprocessed minerals for their standard of living.Not surprisingly, therefore, our economy is highly vulnerable to unstable world commodity market prices.The slump in trade we are currently experiencing (in first quarter 1987-Edition) was brought about by the over supply of the raw materials we produce. However, the recent downturn in world market prices is more serious than previous slumps because in part it is due to technological advances 'in other countries which could have a permanent effect on the world trade of primary products.

Jan 1, 1987

By A McEwan, J Masters, C A. Jackson, A Catanzano, V Sharp, M Millen, S Rainey, S J. Spencer, G Roberts

A passive acoustic emission (AE) monitoring system has been developed and trialled on two M10000 IsaMillsTM. The analyser detects AE stress waves generated by grinding media impacts with the mill liner during mill operation. Locally propagating stress waves can be detected on the exterior liner surface using strategically mounted broadband accelerometers.The analyser has been developed into a robust commercial prototype system, and has been designed, installed and commissioned with Xstrata Technology at two mineral processing plants.A six-month field trial showed large-scale variation in AE power signature with process conditions. Analysis of the enveloped AE power output demonstrated a strong correlation with mill process conditions – more specifically grinding media relative loading, feed pulp density, feed volumetric flow rate and feed type.Placement of accelerometers along the length of the mill body provided key information on the grinding media relative deportment. The enveloped AE power detected by the mill body, discharge pipe and bearing housing sensors all captured information strongly correlated with mill operating parameters and process state.The prototype analyser demonstrates suitability as a long-term online tool for stirred mill performance monitoring, and potentially for optimisation and control, in beneficiation plants.CITATION:Jackson, C A, Spencer, S J, Masters, J, Sharp, V, McEwan, A, Rainey, S, Catanzano, A, Roberts, G and Millen, M, 2014. Monitoring of M10000 IsaMill™ process performance by passive acoustic emissions, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 241–254 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By A Scott, I Onederra

A great deal of technical and research effort has been applied to the development of models to predict fragmentation from rock blasting. A number of quite useful empirical or engineering models are currently available to blasting engineers and consultants, while more sophisticated approaches using mechanistic and numerical descriptions of rock breakage continue to be developed and applied by researchers and explosives companies.The fragmentation resulting from any blast will be heavily dependent on the properties of the rock mass being blasted; however, most empirical models rely on ‘rock factors’ generated from simple rock mass properties to describe the influence of the rock on the blasting outcome. In contrast, mechanistic models need explicit rock mass properties that require sophisticated laboratory measurements and detailed structural data if realistic outcomes are to be generated. The fragmentation modeller is caught between excessively simple rock mass descriptions for the empirical models and excessively complex data requirements for the mechanistic models.This paper briefly reviews the basis of a range of fragmentation models and the rock mass properties on which they rely. Shortcomings in the way that the mining industry tends to characterise the blasting properties of rock are discussed and some practical approaches are described to quantify these properties in both operating and greenfield mining environments. Case studies are presented where specific additional breakage properties and modelling features have been needed to generate a useful description of the fragmentation achieved.CITATION:Scott, A and Onederra, I, 2015. Characterising rock mass properties for fragmentation modelling, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 149–160 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By B Muller

The disposal of tailings has become a greater issue due to the changing economics of mineral extraction. The processing of lower grade deposits and tougher environmental regulations has led to the selection process for tailings disposal options becoming more complicated. Current selection methods are too time consuming or too easily manipulated for inexperienced users to use successfully. This paper examines a different method for the initial selection of a tailings disposal system, using a numerical system that was introduced into the mining method selection field. The numerical method system was compiled by reviewing previous work done on the positive and negative aspects of the tailings disposal methods used by the coal and metallurgical mining industries. Assessing the common trends and design aspects of each of the methods was undertaken and a ranking was designed to explain how well suited the tailings disposal methods are to a situation. The tool successfully analysed sites using common data to indicate methods for disposal that would have provided minimal technical problems, low environmental risk and been practically possible. The tool also proved successful in identifying critical areas that would need further investigation. This new system was tested on some disaster case studies from around the world in order to show that it could have successfully selected a different method for tailings disposal that would have prevented the disaster.

Sep 26, 2011

By Smith F. A, Both R. A

The application of biogeochemical methods in mineral exploration in the semi-arid to and environment of Western Australia was investiga- ted in an area near Norseman. The reliability of these methods was evaluated by comparing trace element characteristics of rock, soil and plants in the vicinity of the Pioneer BB pros- pect. The prospect is located in the south- western part of the Pioneer Dome, where granite gneiss core is surrounded by a 'greenstone' sequence of ultrabasic, basic and sedimentary rocks. Nickel-iron sulphide mineralization occurs discontinuously along one of the basic- ultrabasic contacts. Analyses of unweathered and partly weath- ered rock from diamond drill cores show the ultrabasic rock to be highly variable with re- spect to nickel, copper, cobalt, zinc and manga- nese. Samples of weathered bedrock and over- lying soil were analysed both for total trace element contents and for the trace elements associated with secondary iron and manganese oxides. Approximately 30 per cent of the total nickel content of the weathered basic rock is associated with secondary iron and manganese oxides, compared to approximately 15 per cent in the weathered ultrabasic rock. The soil is partly transported but has a residual component sufficient to provide a reli- able indication of the underlying rock chemistry, although the trace element content of the soil is less variable than that of the rock. Total

Jan 1, 1973