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By C Dick

Over the past three decades, mining operations have seen a significant increase in the use of contractors for mining, camp management and catering, recruitment, maintenance, power management, and commissioning. More recently contractors have been engaged for stores and logistics, OH&S, environmental, exploration, training etc. In some countries, such as South Africa, the trend is towards total outsourcing of all aspects of a mining operation which is coordinated by the owners’ management team.During the Global Financial Crisis (GFC) more Australian companies considered and/or took on this approach to recruiting for both projects and operations as mining companies were forced to rethink their corporate strategies as commodity prices plummeted to low levels, pushing operations and projects into potentially financially unviable territory.This paper discusses the labour recruitment, commissioning and operating strategy of Western Areas NL (WSA), with the assistance of Independent Metallurgical Operations Pty Ltd (IMO), as it progressed construction, commissioning and operation of the Cosmic Boy nickel concentrator at the Forrestania Nickel Project during and post GFC. The use of IMO contractors allowed Western Areas to mitigate labour cost risk during the uncertainty caused by the GFC and let their management team focus on the task of bringing a new operation into viable and profitable production.

Aug 8, 2011

By J Euston

In the 1990s round flotation tanks were introduced as a result of the lower fabrication costs for larger cells. It was soon observed that round tanks held a number of further advantages over the traditional rectangular cells, such as better hydrodynamics, lower costs and reduced footprint per unit volume.In the last twenty years flotation cell sizes have increased almost exponentially and designs of 250 to 300m3 are a well established standard with plans for full scale pilot installations of 500m3. The option to install these large cells gives flexibility in circuit arrangements and allows efficient and economic matching of flotation lines with modern mill designs. The benefits of scale up are well known with reduced numbers of cells required, lower power costs per unit volume, etc. These benefits will be briefly reviewed with specific reference to the installation of 300m3 to 350m3 flotation cells at the Copperton Concentrator of Kennecott Copper in Utah, USA.The sophisticated techniques required to model these ‘supercells’ have led to a critical review of the fundamentals of flotation science and engineering. In addition to outlining the advantages of large flotation cells, this paper will review the science which supports, and occasionally challenges, the ongoing trend to larger flotation cells.

Aug 8, 2011

By R L. Brathwaite

The mesothermal quartz-scheelite lodes of the Wakamarina valley are one of twelve known mined or prospected gold-bearing areas in the Marlborough Schist. Recorded production was 556 kg gold, a little silver, and c. 390 t scheelite. 134 m of the 1800 m long Golden Bar reef are accessible in the No 2 level of the Golden Bar mine. The reef is a typical multi-banded mesothermal vein, mostly c. 1.75 m wide, enclosing narrow horses of schist country rock. Scheelite is sparsely distributed, and is more common in small veinlets in the hanging wall schist. The country rocks are textural zone I-1m schists of prehnite-pumpellyite to pumpellyite-actinolite metamorphic facies. Their geochemistry suggests they are part of the Caples Terrane, and of calc-alkaline volcanogenic arc origin. The associated Wakamarina Quartzite is strongly recumbent folded, and of the same metamorphic grade, with abundant pumpellyite, stilpnomelane, and garnet, presumably spessartine. Although it has geochemical signatures of a deep sea sediment, it is depleted in Cr and Cu, and greatly enhanced in K and Ti, when compared with a standard chert. It also has trace element characteristics of a calc-alkaline arc-related sediment. However, associated greenschist has MORB-like incompatible element chemistry. The Golden Bar reef lies within a steeply dipping, normal to transtensional dip-slip fault adjacent to a shallow-dipping mylonite shear zone, which, at least on the footwall side, is 040 m wide. The shear foliation has been severely dragged down to nearly parallel the Golden Bar reef within 1 m of the quartz lode. Preliminary structural analysis suggests that the shear zone is extensional. X-ray diffraction analyses of the wall rocks show a progressive depletion of amphibole, stilpnomelane, and pumpellyite towards the reef, and enhanced illite/muscovite and Kfeldspar adjacent to the lode, along with possible graphitic carbon within 10m. Two zones of intense quartz veining occur, one adjacent to the hanging wall for 12 m and one from 40 m outwards. Quartz vein systems in the country rock are complex and span from pre-schistosity to post-mylonite. They include multiple generations of quartz, actinolite, stilpnomelane, pumpellyite, albite, adularia, chlorites, illite/muscovite, calcite, and scheelite. Metal analyses across the Golden Bar reef showed gold values of 0.13.1 ppm, and low tungsten values, consistent with the observed sporadic scheelite occurrences. As and Sb are at background levels, but enhanced Cr (150 - 430 ppm) relative to the schists (30 - 41 ppm) suggests that the source hydrothermal fluids passed through and leached mafic to ultramafic rocks.

Jan 1, 1994

By Robson W. D, Irwin D. A

In November, 1932, an investigation of silicosis was undertaken at the, McIntyre Porcupine Mine, Schumacher, Ont., atfer a discussion of the problem with Sir Frederick Banting and his, staff. As a result it was decided to carry on dusting experiments with animals at the mine in a manner that would duplicate as far as possible actual industrial conditions.At that time 50, guinea pigs were placed in the crusher nouse tunnel of the mill where a considerable quantity of fine dust, containing approximately 35 per cent., of free silica, was being constantly produced. These animals lived in this atmosphere for periods up to one year, and, while on autopsy large amounts of dust were found in the lungs, not a single case of silicosis had developed. These negative results suggested, among other things, that the mine gases might be a predisposing factor in the production of silicosis, and the results of this investigation led us to undertake the study of the hydrogen-ion concentration of the condensate of the atmosphere, both in the mine and in various sections of the mill.The C02 combining power of blood serum on a series of 400 miners was also studied at this time. While these results were inconclusive, the variation in the hydrogen-ion concentration of the condensate between the surface and underground atmospheres encouraged us to investigate the effect of neutral, weak acid and alkaline solutions on the solubility of silicious materials. Gye and Purdy were the first to point out that the chemical reaction and not the physical presence of silicious material was responsible for the production of the fibrosis in silicosis. This work was investigated by Gardner and Cummings who showed that the tissue reaction to quartz was definitely proportional to the size of the particle. They found that 1-3 micron particles of quartz produced an acute proliferative fibrotic response while the 10-12 micron particles produced only a foreign body reaction up to a period of three years. It is accepted that the dangerous silica particles retained by the lung are under 5 microns in diameter. We assumed that if the solubility of the silicious material retained in the lung could be reduced sufficiently by the addition of some non-toxic element or compound the usual fibrotic respohse would be modified. We found that the addition of certain compounds to silica would reduce its solubility in the beaker to a slight extent. But these compounds, when mixed with quartz...

Jan 1, 1945

By F M. Weir, M Fowler

The design of excavations in rock must, implicitly or explicitly take into consideration the influence of small- and large-scale geological structures. For most sites the complexity of a fractured rock mass is best captured using a 3D fracture system model based on field data. A discrete fracture network (DFN) approach involves stochastic modelling of the ‘smaller scale’, nondeterministic structures. For slope stability or tunnelling projects DFN modelling provides a valuable geotechnical tool for characterisation of a rock mass and identification of likely failure mechanisms.This paper presents a suite of the DFN modelling undertaken for the design of a large open pit in Australia. The proposed pit is to encounter a 160?m thick, high strength, sheared shale unit, which overlies a crystalline basement. DFN modelling was undertaken separately for both the shale and basement units. While the model inputs and development for each unit are briefly presented, the focus of this paper is on the various applications of the DFN modelling.A key advantage of the DFN approach for design studies is its probabilistic application to structural analyses and results. Multiple realisations of the same model were generated for both the shale and basement units, with the stability analysis carried out on each iteration. The generation of a large number of DFN models and analyses allow assessment of wedge volume, factor of safety and proportion of unstable slope for a range of conditions. The DFN modelling at the case study site was also utilised for a number of other purposes. For example, investigation of likely fault lengths in the shale unit and combined rock mass and defect failure. The development of this tool has been influential in improving our understanding of fracture networks for excavation design.CITATION:Weir, F M and Fowler, M, 2014. Rock mass characterisation and analysis for excavation design – a discrete fracture network approach, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 445–456 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By N Belluz, L Johnson, N Wiwoho, P Manning

The Kucing Liar skarn deposit is located in the Ertsberg mining district, which also contains other skarn deposits and the Grasberg porphyry copper û gold deposit. The Ertsberg district is located in the province of Irian Jaya, IndonesiaÆs easternmost province. Mining development began in the Ertsberg district in 1972 with the mining of the Ertsberg deposit. Daily production in the district now averages about 230 000 tonnes of ore, with the bulk of the ore coming from the Grasberg open pit and the balance from underground mining of skarn deposits. During 1998, 45 218 additional metres of drilling were conducted to delineate and understand the Kucing Liar orebody. The deposit was first intersected in drill holes in 1994 and then was intersected in underground workings located about 1000 metres from the discovery drill hole in 1995. Initially, the two intersections were thought to be different orebodies but are now realised to be different parts of the same orebody. The Kucing Liar deposit consists of magnetite û copper û gold replacement and skarn mineralisation in favorable Tertiary and Cretaceous units. The deposit is approximately 2000 metres in length and averages about 200 to 250 metres in thickness. The width varies from 400 to 600 metres. Drilling in 1998 was directed towards delineating the deposit on its NW and SE ends and to determine its down dip extension. Reserves for the deposit at the end of 1998 stand at 320 million tonnes at 1.4 per cent copper, 1.4 g/t gold, and 5.3 g/t silver. Many important questions remain to be answered concerning the relationship of the Kucing Liar orebody to the major faults in the district and to the Grasberg intrusive complex which contains the Grasberg orebody. Continued exciting developments are anticipated as work to understand the deposit by drilling and geologic study continues.

Jan 1, 1999

By N L. Turner, D J. Robinson, A J. McFarlane, N M. Chapman, L L. Kuhar, R L. Meakin, R Martin

A number of geometallurgical tests have been developed within the AMIRA P843A Geometallurgical Mapping and Mine Modelling (GeMIII) project, an interdisciplinary collaborative research project involving four research groups and over 20 global mineral companies. Researchers at the Commonwealth Scientific and Industrial Research Organisation (CSIRO) have been focusing on the development of predictive hydrometallurgical indices for the GeMIII project via rapid, small-scale, cost-effective tests and protocols for comparative ranking of attributes relevant to leach performance. One of the focus areas has been the development of a leaching scheme for determination of the mineralogical deportment of copper in a large number of samples for geometallurgical applications.Various leaching schemes have been used over the last 20 years to identify the mineralogical deportment of copper. Typically, weak sulfuric acid and cyanide are used to target copper oxides and æsecondaryÆ copper sulfide minerals, covellite, chalcocite and bornite, respectively. Residual copper is assigned to chalcopyrite and/or bornite. Adaptations of this scheme have included the use of a weak organic acid to target oxides or ferric sulfate to target secondary copper sulfides. Testing of the weak acid/cyanide scheme in the GeMIII project using head and residue QEMSCAN mineralogical data analysed with a statistically reliable comparison method indicated that the inferred mineralogical deportment from various leaches could differ markedly from the theoretical or assumed value. Based on this initial work, test development and leach tests on samples from multiple sites has resulted in the development of a scheme to target copper oxides, chalcocite, covellite, bornite and chalcopyrite. This paper presents results from leach tests conducted on a large sample suite from two pits in a Cu-Au ore deposit with results calibrated using mineral liberation analyser (MLA) mineralogical analysis. This study has assisted in the development of a protocol for determining the mineralogical deportment of copper in a large number of samples for geometallurgical applications.CITATION:Kuhar, L L, McFarlane, A J, Chapman, N M, Meakin, R L, Martin, R, Turner, N L and Robinson, D J, 2013. Calibration and testing of a geometallurgical leaching protocol for determining copper mineralogical deportment, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 177-186 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

By J Andrina, D Richar, R Smart, A Neale

The Grasberg is a large copper and gold open pit mine operated by PT Freeport Indonesia and located in the high equatorial mountains of Papua Province, Indonesia. The climate is alpine/sub-alpine with little seasonal variation in temperature and rainfall. The annual precipitation varies from about 3000 to 5000 mm over short distances around the Grasberg, but in general, an average daily precipitation of 10 mm per day applies and leaching of the overburden is continuous throughout the year. Mining commenced in 1988, and almost all of the overburden mined up to 2003 was potentially acid forming. From 2003 to the end of the Grasberg pit operation in 2014, approximately 70 per cent of the overburden will be potentially acid forming and 30 per cent limestone. A major focus of the investigations is developing strategies to maximise the beneficial use of the limestone that will be mined. Laboratory columns and field test pad investigations have been ongoing for six years examining limestone blends. Trial dumps utilising truck placement and conveyor/stacker placement and blending of limestone and acid generating rock have recently been constructed. In addition, based on initial results, investigations aimed at further evaluating the performance of limestone covers in this high rainfall environment have commenced. A significant finding has been the identification of strong armouring layers on sulfide surfaces within well-blended material and under limestone covers. These layers effectively isolate sulfides and thus progressively slow the oxidation rate to a level where the alkalinity load from the limestone exceeds the rate of acid generating. ARD is controlled and neutral low metal drainage results. The results have demonstrated that although limestone blending is effective, it is necessary to ensure that all size fractions within the blend receive adequate acid neutralising capacity to buffer the potential acidity. Because the sulfur content generally increases and the acid neutralising capacity decreases with decreasing particle size in limestone blends, the amount of limestone required greatly exceeds the stoichiometric requirement. This paper describes the development of limestone blending specifications for potentially acid forming overburden and presents the results of the ongoing limestone cover trials at the Grasberg mine.

Jan 1, 2003

By J T. Woodcock

This paper discusses characterisation techniques that can be applied to complex waste products from metal production and processing operations with the aim of devising treatment methods for upgrading the metal content for recycling. Two waste streams were selected to illustrate the role of characterisation in adapting mineral processing techniques to provide an effective recycling strategy. Waste products chosen were:aluminium dross, which contains metallic aluminium particles in a coarse matrix of many components; and steel shredder sludge that contains copper wire and other metallics in a matrix of plastic and natural fibres, iron oxides, metallic iron, and other compounds. Characterisation methods discussed include chemical analysis (XRF, ICP-AES, and selected specialised techniques), phase analysis (XRD, SEM, TEM, and optical microscopy), morphology (IFESEM), sizing analysis (screening, Cyclosizing, Infrasizing, Malvern sizing), and general techniques such as particle shape, surface area, and porosity determinations. The applicability of these techniques to the waste products is considered in relation to their advantages and disadvantages, and sampling issues.Treatment techniques considered for the two waste products included comminution, screening, air or water classification, simple water leaching, gravity separation, magnetic separation, flotation, and eddy current separation.Tentative flow sheets were developed for the two wastes. For aluminium dross, it was proposed to use fine crushing followed by water washing to remove soluble chlorides and aluminium nitride, and then desliming followed by flotation of the granular fraction to give a metallic aluminium-rich concentrate. For shredder sludge, it was proposed to use wet screening, water classification, and gravity concentration to produce a copper-rich product and magnetic separation to produce a metallic iron-rich product.

Jan 1, 2004

By M A. Jardine, J A. Miller, M Becker, M Harris

"Although the role of texture has been increasingly recognised as a geometallurgical indicator of ore characteristics and their variability, the ability to appropriately quantify and correlate it with metallurgical performance remains an ongoing challenge. In this study, we propose the 3D characterisation and quantification of ore textures from drill core using X-ray computed tomography (XCT) with an appropriate image analysis methodology (grey level co-occurrence matrices, GLCM). This methodology has been specially customised for application of 3D XCT grey-scale volumes. This approach has potential as an online mine site analysis tool providing detailed 3D information on both quantitative texture and simple mineralogy.The approach is illustrated in this paper using drill core samples that were manually extracted from various rock types and textures representing the Nkomati Main Mineralized Zone (MMZ) sulfide nickel ore deposit. A preliminary classification of the samples was performed based on their particle size distribution after laboratory scale rod milling. Accompanying QEMSCAN analyses were also used to guide the interpretation of the grey-scale mineralogy and texture in the 3D XCT volumes. The resultant GLCM produced from quantitative 3D image analysis of the XCT volumes indicated sensitivity to ore variability and was able to capture a simple mineralogy and grain size distribution. The approach holds many possibilities for geometallurgy, of which the potential for automation is promising.CITATION:Becker, M, Jardine, M A, Miller, J A and Harris, M, 2016. X-ray Computed Tomography – a Geometallurgical Tool for 3D Textural Analysis of Drill Core?, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 231–240 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By J F. C L Costa, J C. Koppe

It is recognised by the major international codes that resource classification involves the interaction of numerous qualitative and quantitative criteria such as data quality, geological and grade continuity, etc. However, the difficulty in quantifying the degree of uncertainty associated with mineral resources estimation has led to the creation of a large suite of methodologies, terms and definitions, with almost every mining company having its own set of standards. It is also intuitively known that several traditionally used methods to evaluate resources do not take into account the spatial continuity of the grades, being unable to provide a reliable measure of the error associated with their estimates. Since they do not provide an error assessment, these methods are inappropriate to assess local or global uncertainty associated with an estimate. Faced with these problems, this work aims at developing a methodology for either quantitative or qualitative analysis of mineral resources estimation, through incorporation of uncertainty and the correct definition of the associated risk or error. The proposed methodology includes the development of a software code incorporating all the main classification techniques used by the mineral industry. A comprehensive study about each technique was conducted allowing a comparison of the parameters affecting mineral inventory assessment. A case study was conducted with a typical iron ore deposit data set from the Conceitpo mine of the Itabira Complex in the Iron Quadrangle, Brazil. The results showed the specific limitations of each classification system and the influence in selecting their key parameters, always based on subjective choices.

Jan 1, 2009

By T Blyth, D Holden, N Archibald, S Huffadi

The Morning Star mine is owned by Hill 50 Gold NL. Gold is hosted in quartz-carbonate ¦stibnite ¦molybdenite veins that occur in a series of deformed, altered and metamorphosed mafic volcanics with subordinate sediments and felsic intrusive rocks. The irregular gold distribution and its relationship to structure and alteration intensity makes the definition of stoping limits difficult. Understanding the structural evolution of the orebodies and the contemporaneous and later structures that affect the orebodies has been very useful in this context. This paper reports on a detailed mapping exercise (as part of a more extensive and on-going investigation) and the integration of this mapping with other geological and grade control data in a 3D modelling environment to provide an expanded basis for stope design. Three types of mineralised zones can be discriminated based on the morphology of the veins within. They are:those associated with strongly folded, thick veins (approximately 1 m thick eg 05 orebody); those comprising planar, boudinaged and some folded veins which consolidate to form tabular, steeply dipping bodies (eg 010 orebody); and zones containing the above vein types and thin, highly deformed veins within zones of intensely foliated country rock that result in localised, irregularly distributed high-grade gold zones (eg 02 orebody). The mineralised zones associated with thick folded veins are typically predictable over many tens of vertical metres. The second and third types of ore zone is generally less predictable. Detailed mapping and structural kinematic studies indicate all ore zone types are affected by progressive deformation involving strong strain partitioning. It is interpreted that high strain zones, recognisable by intense foliation development and highly deformed veins, are the latest stage of a progressive deformation which approximates bulk flattening. Structural controls on mineralisation can be defined at two different scales.Regional scale folding has deformed a sequence of mafic volcanics with interlayered sediments and felsic intrusives. Initial geometry of felsic bodies relative to orientation of the primary lithological layering and the bulk shortening direction is interpreted to be critical for initiation and development of strongly dilatant zones within this package of rocks, and Local scale dilation is evidenced by development of several vein sets whose range in orientations and opposed vergence relationships suggest a pre-folding origin comprising both extensional and hybrid shear-extensional types. Continued deformation resulted in folding of these veins with strong strain partitioning. Major vein packages are closely spatially associated with the felsic/mafic contact and an interpreted early structure which appears to have partitioned early dilation. This structure is now obscured by strong deformation but is currently represented by a zone of planar veins.

Jan 1, 2000

By M J. Gillespie, P D. Erskine

Mine site rehabilitation generally includes the re-shaping of overburden to create a final landform, manipulation of substrates and subsequent revegetation. Due to the wide range of environmental variables that influence rehabilitation progression, having clearly-stated final land-use goals and ongoing significant contributions to the planning process, from prefeasibility through to mine closure, is essential for achieving stable landforms and sustainable rehabilitated communities. Two examples of rehabilitation processes in the phosphate rich region of North West Queensland are used to illustrate some of the possible benefits of early planning and communication of rehabilitation requirements.Approximately 160 km south of Mount Isa, Incitec Pivot Limited operates a 35 year old open cut mine at Phosphate Hill. Monitoring of rehabilitation areas and selected analogue sites is undertaken annually, but the initial landform design, substrate management and species selection has created a difficult environment for revegetated areas to successfully establish. Constant management input (such as weed management, erosion control, supplementary seeding, etc) will, therefore, be required over a long time frame.The second example uses exploratory drilling and historic costean pits at Legend International HoldingÆs Paradise South site, 135 km north of Mount Isa, to determine the success of natural vegetation colonisation on waste rock and compacted soils, and the effects of cattle grazing on recolonisation. This information can be used by planners of the mine life to inform possible end-land use decisions and proposed completion criteria.In a semi-arid environment such as North West Queensland, the creation of a post-mine landscape suitable for nature conservation and/or grazing can be an arduous task. The input from environmental personnel at all stages of the mining process will positively impact upon the quality of the resulting rehabilitation and ensure undesirable legacy issues are minimised.CITATION:Gillespie, M J and Erskine, P D, 2012. Importance of early rehabilitation planning - Case studies from North West Queensland, in Proceedings Life-of-Mine 2012 , pp 187-196 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By L Smith, R Beckie

Controls on environmental loading from acid rock drainage (ARD) are not well understood in waste rock material. In particular, relationships between subsurface flow and the timing, duration, and intensity of leaching of metals and acidity from waste rock dumps remain ill defined. This study investigates field-scale relationships between subsurface flow processes and geochemical processes in unsaturated waste rock. A 12-metre tall, unsaturated waste rock pile, constructed in 1994, was deconstructed and sampled at Key Lake, Saskatchewan, Canada, during the summer of 2000. A detailed sampling methodology was developed to characterise physical and chemical properties of waste rock material within the waste rock pile. Physical properties were characterised by measuring soil-water suction, volumetric water content, and grain-size distribution at 60 random locations within the pile and grain-size distribution at 20 grid locations within the pile. Attempts to develop a field-based soil water characteristic curve from physical field-data failed due to spatial variability and hysteresis of waste rock properties. As a result, grain-size distribution was used as a relative measure of subsurface flow. Paste pH, pore-water geochemistry, mineralogy, and water-soluble extraction results were used to characterise geochemical processes and sulfide oxidation at each of the 20 grid locations. Geochemical characterisation results demonstrated the preferential weathering of marcasite relative to pyrite and chalcopyrite. Dolomite was the main buffering carbonate mineral. Gyspum, jarosite and iron oxyhydroxides were the main secondary minerals. Pore-waters contained up to 800, 11.7, and 6 mMolar (78 000, 690, 1400 mg/L, respectively) of sulfate, nickel, and uranium, respectively, suggesting significant weathering has occurred. Measures of weathering indicators show no discernable correlation with grain-size distribution nor do they show any spatial relationship within the sampled grid. Reasons for this may include limited duration of waste rock exposure to weathering and development of fluid flow-paths, and limitations of characterisation methods used. Indeed, six years may not be long enough for weathering patterns to develop due to fluid flow-paths in this unsaturated waste rock pile.

Jan 1, 2003

By A Buckley

Many policy issues facing the mining industry and affected communities are at a level of complexity that they can be called ‘wicked’ problems. The term ‘wicked’ in this context is used, not in the sense of iniquity, but rather as social and economic issues highly resistant to resolution. For the resource extraction sector and affected communities there are an array of challenges embedded in the industry’s production and profit paradigm, the remoteness of mineral reserves and affected communities’ expectations of economic benefit and a positive legacy. The mining industry as a whole is dominated by economic, political, legislative and market structures that influence and constrain interactions between mine operations and local communities. For communities, with particular reference to regional Western Australia, intractable problems include the uncertainty of, yet increasing dependence on, a mining economy. Questionable outcomes for local communities include the limited realisation of local employment and business development benefits, and low overall outcomes or low multiplier effects. ‘Wicked’ problems, according to the literature, are best addressed via collaboration. In the mid-west region of WA, with mining and infrastructure construction underway, alliances have formed between mining companies, the major port and rail infrastructure project (Oakajee Port and Rail) and regional and local governance stakeholders. The major impetus for these affiliations is to expedite planning and associated infrastructure development taking into account the lessons from other mineral-led regions. What has resulted is an array of innovative approaches to stubborn problems including planning well in advance of full-scale mining; regionally coordinated procurement; ‘mine ready’ local businesses; and strategic investments in social infrastructure; including community trust funds paid in advance of project delivery. This paper examines these innovative approaches/alliances and assesses their effectiveness in addressing long standing mining/community dilemmas.

Nov 22, 2011

By D Timms

The Kempfield deposit is located in the Hill End Trough, one of several intracratonic basins developed during Silurian–Devonian time, in the eastern province of the Lachlan Orogen, Eastern Australia.The deposit contains an oxide resource of 5.8 Mt @ 58 g/t Ag and a sulfide resource of 14.4 Mt @ 45 g/t Ag, 1.7 per cent Zn and 0.6 per cent Pb, classified and reported in compliance with the JORC Code. The deposit has been previously explored by a number of companies, including INCO, Shell, Jones Mining, Golden Cross Resources and recently Argent Minerals Ltd (Argent). Argent is currently completing a definitive feasibility study with a view to mining the deposit.The deposit is hosted at the boundary between the Molong High to the west, comprising Ordovician sediments and volcanic rocks and the Hill End Trough to the east, interpreted as a back-arc basin containing Silurian sediments and siliceous-feldspathic volcanic rocks. The boundary between these two strato tectonic units is an imbricate thrust fault zone known as the Copperhannia Thrust.The Kempfield deposit is hosted in felsic volcanic rocks known as the Kangaloolah Volcanics. These have been in-faulted and folded into the Middle Ordovician meta-sediments of the Coombing Formation of metasediments along the Copperhannia Thrust. The Kangaloolah Volcanics belong to the Late Silurian Mumbil Group, comprising submarine carbonate-shale facies interspersed with extensive felsic volcanic piles, which grade conformably upwards into turbiditic sandstone and siltstone sequences (interpreted to represent a deeper depositional environment). These turbiditic rocks are known as the Campbells Formation, comprising siltstone, sandstone and andesitic tuff. The rocks at Kempfield are metamorphosed to lower greenschist facies, reflected through the different type of schists.Silver, gold, lead, zinc mineralisation is hosted in barite-rich horizons, near the boundary to quartz-phyric tuffaceous rocks in submarine, immature, reworked felsic ash tuffs. Barite appears to be hosted in greatest concentrations by the coarser grained volcanoclastic sandstones and grits, whilst intercalated siltstones are volumetrically minor and tend to return low barite and silver. Mineralisation is hosted in stratiform and probably stratabound barite-rich horizons. A northeast-trending, steeply dipping, metamorphic cleavage (S1) occurs throughout the project area.

Aug 22, 2011

By H J. Dalstra

High-grade iron ore may be derived from banded iron formation (BIF) through four fundamentally different processes:1. syngenetic precipitation of chert free BIF,2. residual enrichment by removal of gangue minerals from BIF to form bedded (residual) ironore,3. mechanical erosion of iron oxide and chert from bedded iron ore or BIF and re-deposition andupgrading as detrital iron ore, and4. chemical removal of iron from BIF and precipitation elsewhere as a secondary (channel) irondeposit.Finally, the BIF itself may constitute iron ore if a high-grade concentrate utilised for pellets or sinters can be derived from it through mechanical (industrial) separation of iron oxide by means of crushing/milling and mineral separation.Historically, exploration for high-grade BIF hosted iron ores was focused on the residual (bedded) deposits and driven by supergene concepts. Exploration for detrital and channel type iron ores was mostly secondary to exploration for bedded deposits, but recently, a more focused exploration effort has led to the discovery of enormous moderate to low iron grade deposits in the Pilbara region of Western Australia. Exploration for high-grade iron ores using syngenetic concepts has been limited,but together with exploration using hypogene concepts offers the best hope of fi nding concealed deposits. Exploration for BIF sources suitable for concentrate ores commenced in the ‘old’ iron ore provinces after the high-grade resources were depleted and has only recently gained importance in Australian BIF provinces, mainly as a result of high iron ore prices in the last decade.

Jul 11, 2011

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 D Tanzil, H Jones

Every mine will close! Charting a profitable course through mine operations to acceptable mine completion requires that risk and opportunity management planning of the mine life begin as early as possible in the life cycle. Management targets and metrics are required to identify and navigate the course to successful mine completion based on economic, social and environmental criteria. This paper outlines the application of The Metrics NavigatorÖ principles to the life cycle of a mine site. In general, metrics are required to make key strategic ideas apparent, transforming those ideas into a manageable set of quantitative measures that guide communication and decision making. For example, the chemical industry has established metrics that focus on the life cycle impacts of its products and eco-efficiency of their processes. Other industry sectors have focused attention on workplace and community well-being outcomes. These management metrics are necessarily organisation-specific, aligned to stakeholdersÆ expectations and the strategic outcomes sought, as well as the cause-and-effect relationships underlying key issues. Recently, the Global Environmental Management Initiative (GEMI), a consortium of multi-national companies, developed The Metrics NavigatorÖ. The guidance document provides a structured process for assessing and developing metrics for key environmental, social, and economic issues based on business and stakeholder perspectives. It incorporates best practices learned from the chemical and other industry sectors and has since been applied to develop metrics that guide life cycle strategies. The paper examines how the life cycle of a mine site could benefit from experiences in other industry sectors where sustainability metrics have guided strategy. It considers the potential application of The Metrics NavigatorÖ process to the life cycle of a hypothetical Australian mine site using the processes that have been successful in other industry sectors.

Jan 1, 2009

By A Madera, R Watt

The Tampakan deposit is a strongly telescoped high-sulphidation-epithermal/ porphyry deposit pair which is hosted by a sequence of probable Pliocene age subaerial andesite flows. These host units lie on the western flank of a deeply dissected andesitic stratovolcano within the northernmost portion of the Sangihe Arc in southern Mindanao. The deposit was discovered by WMC geologists in 1992 and is currently undergoing resource evaluation. Preliminary resource estimations indicate a total inferred metal content of 12 million tonnes of copper metal and 16 million ounces of gold. Using a 0.2 per cent Cu cut-off grade, the deposit has a current mineral resource of approximately 2.5 billion tonnes with an estimated grade of 0.48 per cent copper. At a higher cut-off grade of 0.5 per cent Cu, the mineral resource is approximately 900 million tonnes with an estimated grade of 0.75 per cent copper. Mineralisation is open both to the west and at depth. The Tampakan district is centrally located with respect to a 100 km wide zone of left-lateral strike-slip deformation represented by the trans-Mindanao Cotabato Fault Zone. The district is transected by several WNW-striking wrench faults which represent strands of the regional Cotabato Fault Zone. High-sulphidation epithermal mineralisation within the Tampakan deposit is strongly controlled by NNE-trending faults which lie along a dilational orientation within the Pliocene stress field associated with the Cotabato strike-slip fault zone. The mineralisation is broadly hosted by a gently-dipping, tabular zone of partial to massive silicification which displays multi-phase brecciation, acid-leaching, related vuggy porosity and which is developed within a district-scale advanced-argillic and argillic lithocap exceeding 90 km 2 in area. High-sulphidation epithermal mineralisation is associated with a silica-pyrophyllite-dickite-alunite-diaspore¦sericite alteration assemblage which is transitional downward to sericite-chlorite alteration and relict potassic biotite-chlorite-magnetite-anhydrite alteration associated with pervasively developed but weakly mineralised porphyry quartz stockwork veins. The high-sulphidation mineralisation is dominated by disseminated, vein and vug-filling enargite-bornite-digenite-chalcocite-covellite ¦ molybdenite which has overprinted an earlier phase of porphyry copper stockwork veins associated with high-level porphyritic hornblende diorite stocks. The distribution of high-sulphidation alteration and mineralisation reflects strong stratigraphic and structural controls. The high-sulphidation mineralisation covers a surface area of approximately 1.6 km by 2.0 km and forms a tabular, flat-lying to gently-dipping body between 200 and 500 metres thick. It is intersected at RL-1200 m ASL (at surface) in the northern portion of the deposit and extends down to RL-600 m ASL at the southern end. The deposit has been diamond-drill tested to a depth of 400 - 500 metres where low-grade chalcopyrite-bornite-pyrite mineralisation is hosted by pervasive quartz stockwork veins. This deep-level mineralisation represents the outer portion of a porphyry Cu system hosted by both andesite flows and the uppermost portions of high-level hornblende diorite stocks. Deep drilling to test for higher tenor porphyry Cu mineralisation is planned.

Jan 1, 1999