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By L E. Krause

This paper discusses the considerations for optimum maintenance of critical ore handling infrastructure in order to minimise the cost to the business of maintenance periods. As maintenance periods are a direct interruption to production, time is of the essence and careful management of shutdown periods is essential. The ore pass systems currently in use at Xstrata Copper û Mount Isa Copper Operations are up to 30 years old and have had significant wear over the years. The maintenance of these passes and their brows and chutes in a production situation is a challenge as it can potentially expose personnel to high risk situations in addition to the production interruptions. Some alternatives for mitigating the risk of working in ore passes including plugging and ballooning are described. Criteria are included for selecting a method for the safe entry into a given ore pass. Experience in adapting the method of ore pass plugs and some lessons learnt in the process are also discussed.

Jan 1, 2005

By S M. Arndt, D Tyler, F Reusch

Although significant advances have been made in understanding the mechanics of pit slopes, numerical modelling hasnÆt significantly impacted on the reliability of the design process. It is well known that legacy modelling approaches donÆt simulate large slopes well. In recent times, the emergence of very large finite element (FE) models with more than ten million degrees of freedom and the ability to simulate a large number of discrete structures, has allowed a step change in the simulation precision for slopes. The model size allows global and local effects to be realistically simulated in one model for the first time and the process can be better integrated into normal open pit slope engineering processes. Some examples of simulation of very large open pits are shown that demonstrate the challenges and some recent advances in modelling large slope behaviour. Significant limitations in the current measurement and observation regimes of open pits have been identified.

Jan 1, 2007

The ore deposits investigated are composed primarily of hcmatite and can be grouped into three categories depending on the amount of leaching of silica and carbonate which has occurred from the original iron formation, and on the amount of recrystallization of the hematite. Minor constituents are magnetite. goethite, and quartz.Texturally. there are five different types of hematite, formed at different stages during the genesis of the ores.These are1. anhedral hematite grains formed by recrystallization of hematite already present in the original iron formation.2. hematite formed by martitization of euhedral magnetite, 3. massive aggregates of fine- to medium-grain hematite formed by recrystallization of (l) and (2).4. tabular or prismatic hematite grains occurring around the boundaries of the massive aggregates or martite euhedra. and in fractures and5. specular hematite. which is present in fractures in ore types (l) to (4).Minor and trace-element analyses, determined using an electron-probe microanalyser. indicated that only silica (less than 0·01 per cent) and cobalt (less than 0·002 per cent) were present in the magnetite and hematite from unaltered iron formation and in the hematite from the ores. Low concentrations of trace elements are typical of magnetite in ores formed as marine precipitates. On the basis of the analyses alone. it proved impossible to distinguish between the five hematite types. A determination of the variation in rare-earth trace element contents between iron oxides in the iron formation and iron oxides in the ores indicates that the rare earths were depleted during ore formation. A possible explanation is that they were removed in solution with silica as it was leached from the iron formation.

Jan 1, 1971

By A Whaanga, A Doecke

The internal stratigraphy of the Marillana Creek palaeochannel Tertiary channel iron deposits (CID) in the Hamersley Province of Western Australia was initially defined in the 1980s and redefined as the Marillana Formation in the early 2000s. Recent drilling, open pit mining and field observations in the Western deposits at BHP Billiton Iron OreÆs Marillana Creek tenements have revealed some additional details on the extent and detail of some units of the Marillana Formation stratigraphy in this area. The drill hole data at Western 1 South has identified a number of features either not previously documented in this area or whose significance has not been adequately recognised, including a denatured zone at the base of the Upper CID of the Barimunya Member, and variations in the lithology within the Munjina Member at the base of the channel. Additionally, the Western 4 pit walls show evidence of a significant near-surface clay horizon and overlying CID, which are suggested to be the equivalent of the Iowa Eastern Member in the Eastern deposits. The deposition of this unit was most likely driven by a regional climatic disruption rather than a change in sediment source area alone. The nature of the Weeli Wolli Formation-derived goethitic peloids in the Western deposits may explain the more extensive denaturing in the Western Lower CID of the Barimunya Member. In contrast, the more robust nature of the haematitic-cored pelletoids in the Central and Eastern deposits has resulted in a less denatured Lower CID in these areas. Such work reveals the value of and need for geologistsÆ ongoing face mapping observations and detailed drill hole logging, and cautions against not querying previously accepted interpretations.

Jan 1, 2007

The Broken Hill Proprietary Company Limited (BHP) started as a silver-lead-zinc mining company in Broken Hill, New South Wales, Australia in the 1880s. Since then it has diversified into the resource industries of steel, iron ore, coal, petroleum and copper. BHP World Minerals is a Business Group of BHP which is one of the worldÆs largest and most diverse mineral resource enterprises. BHP supplies raw materials for steelmaking, copper concentrate and other mineral commodities to customers in more than 45 countries. BHP World Minerals has operations spread throughout the world û in Australia, the United States, Brazil, Zimbabwe and Canada. Commodities produced by BHP World Minerals currently include silver, lead, zinc, titanium minerals, platinum group metals and coal. The BHP World Minerals Cannington silver-lead-zinc mine in Queensland, Australia is a return to the cradle of BHPÆs early silver-lead-zinc years. This paper compares the success factors and challenges at Broken Hill and Cannington.

Jan 1, 1998

By K Kinnunen

A strong correlation between the reduction degradation index (RDI) of production sinter and the titanium content of the sinter mix was identified at the Ruukki sintering plant between 2000 and 2004. The titanium distribution in different mineral phases was studied using samples from pot sintering tests. Titanium additions were made using two different materials: rutile and crushed titanium-bearing haematite pellets. While both titanium additions clearly increased the RDI, titanium seemed to favour secondary haematite. The study focused on the effect of titanium in haematite, because haematite is reduced to magnetite in the RDI test. During the haematite-magnetite reduction, reduction degradation was observed. To increase accuracy, the phenomenon was investigated first by sintering and then reducing synthetic minerals under controlled laboratory conditions at the University of Oulu. The effect of titanium oxide in solid solution in magnetite on the magnetite to haematite transformation rate was studied first in order to simulate the final stage of the sintering process. In other experiments, haematite samples doped with 0.5, 2.0 and 5.0 wt per cent titanium oxide were studied using thermogravimetry under a controlled gas atmosphere (CO/CO2/H2/N2). Sintered samples were reduced using the same gas composition as in the RDI test. Polished sections for optical microscopy and SEM-EDS analysis were prepared from both reduced and oxidised samples and unreduced sintered samples. The titanium oxide content of haematite had a clear effect on reduction degradation of the samples. Furthermore, increasing titanium oxide content in solid solution in magnetite radically accelerated the oxidation rate. Similar observations regarding the effects of titanium have been reported earlier, but this was the first time the effect of very small additions of titanium were shown to deteriorate blast furnace burden quality and a reason suggested behind the process.

Jan 1, 2007

Historical exploration of the Ballarat East goldfield defined two primary quartz vein lode types. Tracking the intersection of these lodes with vertical lines of enrichment (or so-called æindicatorsÆ) was the basic practice for historical mining. This strategy proved highly successful in terms of identifying quartz veins associated with mineralisation. However, it provides little understanding of the timing or processes involved in the formation of these veins, or the associated emplacement of gold. Current underground mapping shows the Ballarat East gold deposit can be subdivided into four stages of vein formation. The earliest veins (V1 and V2) strike north-south and formed during bedding flexural slip and limb thrust fault propagation in parasitic chevron folds. V3 veins are subhorizontal and relate to further fold tightening involving a transition from east-west compression to north-south extension that initiated re-shear of bedded slip surfaces and additional strike-slip faults. Sporadic V4 veins overprint the shallow-dipping sections of V2 and V3 veins and are associated with weak north-south compression. The V4 veins mineralogy is distinguished by a high carbonate content and sphalerite-galena sulfide assemblage. Vein sampling indicates a significant increase in gold mineralisation where overprinting by the later deformation/veining has occurred. As a result of these observations, a new model is emerging that identifies the chronology, structural control and spatial distribution of respective quartz vein types. This is a major advance in terms of exploration targeting, resource modelling and mine planning.

Jan 1, 2008

By Ormsby W. R, Farrar L

The stratigraphy of the central Pine Creek Geosyncline has been simplified into a three-fold subdivision comprising the Batchelor, Frances Creek and Finniss River Groups. The Batchelor Group consists of a sequence of shallow water coarse clastics and crystalline carbonates and is conformably overlain by the marine carbonaceous shale dominated Frances Creek Group. Interbedded within the carbonaceous shale are turbidites, iron formation, tuffs, carbonate and non carbonaceous shale. The Finniss River Group is a flysch sequence of greywacke and mudstone. The stratigraphic and structural evolution and igneous history are all interrelated. Although the Batchelor Group may have formed in a tensional regime, it is likely that regional compression and accompanying thin skinned deformation began during deposition of the Frances Creek Group. Continued compression resulted in D2 folding d6collement deformation, wrench faulting in compressional zones and thrust faulting. Occasional relaxation of compression is marked by a number of periods of basic intrusion and perhaps distal volcanism. The style of deformation within sediments varies away from granitic basement highs and is similar to that observed around salt domes and found in experimental diapiric models. Sedimentary facies changes also indicate local emergence of basement highs during sedimentation. As compression continued, the deposition of thick sequences of the Finniss River and El Sherana Groups brought about regional metamorphism. Relaxation of compression and waning of associated subsidence resulted in a relative increase in the rate of uplift and partial melting of diapiric sialic basement. In places, granitic magma moved upwards and crystallised forming grossly concordant bodies. Other masses moved laterally and formed extensive granitic sills. Later compression periods caused mainly brittle deformation which may have been strongly influenced by underlying basement fabric.

Jan 1, 1994

By C A Heinrich, Morse M. P, Cruickshank B. I, Pyke J. G, Whitaker A

Very little public domain information is available on the exploration signature of the Coronation Hill Au+Pd+Pt deposit. From 1987 to 1990 the BMR (now AGSO) carried out geological, geophysical and geochemical (whole-rock, stream, soil and rock chip) surveys within the South Alligator and Kakadu Conservation Zones and defined several key parameters useful for exploration programs. The essential geological ingredients for the style of Coronation Hill Au+Pd+Pt¦U deposit are oxidised, low pH fluids, dilatant fault structures, a thick neutral to oxidised cover sequence and chemical traps in the basement. In geophysical data, the areas surrounding the mineralisation can be detected by airborne magnetics as major lows in magnetite-rich rocks, whereas in airborne gamma-ray spectrometry data, imaged spectrometric channel ratios such as U2/I'h and U2/K highlighted alteration surrounding the deposits. Three types of stream-sediment and soil samples were taken from each site: (1) -1 mm mesh, 5 kg sample for bulk cyanide leach (BCL) analysis for Au, Pd, and Pt; (2) 1 kg sample of -1 mm mesh sediment for fire assay/ICPMS analysis for Au, Pt and Pd; and (3) 50 g - 180¦ mesh sample for a variety of trace element analyses, including Au, Pd and Pt. Techniques 2 and 3 gave similar results for Au, Pt and Pd, while the recovery rates for Pd and Pt from the BCL samples were considerably lower. Other trace elements did not define unique indicators for Pt or Pd mineralisation, as each sample reflected the dominant lithology in the drainage basin. Rock chip surveys were useful in determining which faults were associated with the ore fluid in regions of multiple fracturing. Results from these exploration-style surveys also confirmed that the Coronation Hill deposit is a variant of the unconformity-style of mineralisation, as all significant geochemical and/or geophysical results occur at or below the unconformity.

Jan 1, 1994

By S Sabanov

Supplementary sampling of particulate mass concentration, the number concentration and the average particle diameter of nanoparticles using a TSI Dust-Trak DRX Aerosol Monitor, Naneos Partector 2 has been conducted. The aim of this study was to evaluate suitability of the instrument for long-term monitoring of diesel particulate matter (DPM) at conditions of polymetallic mines. Sampling was conducted in an area of the active ore heading, requiring the use of a diesel-powered face haul-age loader R1700 and a mine truck Caterpillar AD-45. The sampling was done for 126 minutes at a distance of 30 metres from the mine face. Results of this field work can be used to expand the sampling program to other mines. Expected outcomes of this study are to develop costeffective DPM control strategies, improve mine ventilation, and protect mineworkers’ health.

Oct 12, 2022

By McConachy G. W, Wright J. V

During the 110 years since the discovery of the Broken Hill PbZnAg deposit six major mining companies have mined the ore body and explored the ore environment. Despite this activity, no new orebodies have been found at Broken Hill. The failure to discover large new resources cannot be attributed to a lack of activity because major companies have maintained substantial exploration commitments over many decades. This suggests that not only was a unique coincidence of conditions required to form the deposit but also that full recognition and definition of the critical parameters may not yet have been recognised. In an attempt to illuminate some of the more unusual and poorly studied characteristics of the ore environment some new areas of investigation are presented here which may contribute to understanding the ore deposit setting and focus exploration towards different and perhaps more productive targets. Sedimentological characteristics of the host succession of the Broken Hill deposit are apparently unique along the line of lode. An upward-coarsening megasequence reflected in the development of clastic psammites stratigraphically below the ore deposit is one important ingredient which has received little exploration focus. These psammites also host mineralisation and form part of a spectrum of quart-zrich rocks collectively referred to as gametiferous psammites, garnet quartzites and blue quartz lodes. Sedimentological data interpreted from outcrop, drill core and downhole geophysical well logs support a elastic origin for some of these rocks; an interpretation which is at variance with traditional interpretations favouring an exhalative origin. A clastic origin for many of the footwall psammites, and their close spatial association with the orebodies suggests their role in ore formation was important. It is interpreted as a critical part of the fluid flow architecture within the sedimentary basin, which focussed ore forming fluids into an unique environment favourable for trapping mineralisation. Detailed stratigraphic correlation near the deposit has also highlighted that quartzofeldspathic rocks (Potosi gneisses and lode pegmatites) have complex relationships with ore. Suites of stratabound quartzofeldspathic pegmatites have received limited study, but their distribution and voluminous development suggests they may be as important to ore formation as the psammitic lode rocks which host the orebodies. These associations are not in conflict with some recent ore forming models invoking deposition in a shallow water environments of deposition. The geochemistry of parts of the host sequence has been studied extensively in the past but this has not been merged with current stratigraphic subdivisions. A large drillhole data base now permits the geochemistry to be related to the sedimentary succession and reveals that a signature involving stratigraphic vectors best illustrated by changes in MnO, Na2O, Pb and Zn can be detected. This is interpreted to reflect sedimentary basin processes as opposed to a classical volcanic hydrothermal alteration pipe associated with seafloor venting. The stratigraphic setting together with characteristics of some of these poorly understood areas is discussed to emphasise that construction of sound models for exploration requires the total ore environment to be studied with attention directed to the geometry and setting of the full range of host rocks. Control of the greater portion of the line of lode by a single company, Pasminco Australia Limited, now permits disparate datasets and observations to be merged and presents new opportunities and encouragement for model refinement and exploration success.

Jan 1, 1993

By L Richards, R L. Brathwaite, C Mazenga

Underground mining of gold-silver bearing quartz lodes was carried out in the great mines at Martha Hill, Waihi over 70 years from 1882 until 1952. Shafts and stopes reached a total depth of 600 m on 16 levels, with workings extending laterally some 1.6 km, and as new reefs were discovered the workings extended beneath parts of the township. Over their long life the mines produced 1217 tonnes of gold-silver bullion from processing 12.2 million tonnes of mined ore. In the early-1980s drilling proved large reserves of gold and silver ore remaining in stock-work zones between the previously mined lodes. This led to a new era of mining at Waihi with the opening of the Martha Hill open pit in 1988. A series of three sink holes have formed above unfilled stopes of the Royal lode. In 1999 a sudden collapse crater 40 m in diameter occurred near an occupied part of Waihi, placing in danger several houses and a busy street. This crater formed close to a similar crater that occurred in 1961. The 1999 collapse resulted in subsurface investigations and risk assessment studies being commissioned by the local Hauraki District Council. However, a further 50 m diameter collapse crater in December 2001 formed in a residential area, swallowing and wrecking an occupied house, fortunately without injuring its five occupants. Two other houses were perched on the crater rim. The 2001 collapse led to an acceleration of the work being carried out by the Institute of Geological and Nuclear Sciences Ltd. (GNS) to identify the extent of the old underground workings at Waihi. For the risk assessment detailed rock mechanics analyses were made to consider the stability of the underground mine stopes, in terms of the stope back, hangingwall, footwall and crown pillar failure mechanisms, as well as void migration. The collapse crater areas were analysed using using several methods, including analysis to simulate the probability of void migration from unfilled stopes to the surface using the @Risk program. The analyses show that in the cases of the actual collapse craters, the voids have a high probability of migrating to the surface, thus providing a method of testing the void migration modelling. Modelling analysis applied to the remaining stopes of the old underground mines show there are further areas where void migration from unfilled stopes has a high, medium and low probability of reaching the surface as a collapse crater. The locations of these probabilistic hazard zones were outlined using the @Risk modelling and deterministically by using the dimensions of the historical collapses applied along the length of the stopes. Consideration of the æincubation periodÆ (the time interval between the cessation of mining and the occurrence of collapse) and comparisons with mine subsidence histories overseas, indicates that further collapses are likely to occur over the next 50 years. Risk assessment estimates made using property values and occupancy levels within the three hazard zones, were compared with Societal and Individual Risk criteria. Results indicate that safety within the high and medium zones may be unacceptable.

Jan 1, 2003

Remnants of Plio-Pleistocene hot spring systems in Northland, New Zealand contain sulfide minerals, principally pyrite, marcasite and cinnabar. The climate is warm temperate to subtropical, with up to 3 m of rainfall per annum, and rocks are deeply weathered. Decomposition of the iron sulfides in natural outcrops and human excavations results in acid rock drainage with pH typically between 2 and 5, and locally down to pH 1. Deeply weathered basement greywacke is clay-rich and has negligible neutralisation capacity. Some overlying volcanic flows have resisted weathering, and pH is kept near neutral by relict secondary calcite in small areas. Natural rainforest soils commonly have pH between 4 and 5 over mineralised and unmineralised greywacke. Mineralised zones are enriched in arsenic, which occurs in solid solution (up to 1 wt per cent) in sulfides and phosphate minerals. Mercury also occurs in solid solution in some of these minerals, as well as in cinnabar. Base metals are present in low (background) concentrations only. Decomposition of the iron sulfides and phosphates releases the solid solution arsenic and mercury into the acid rock drainage solutions. Arsenic is readily adsorbed on to iron oxyhydroxides formed in acid rock drainage situations, and can be effectively removed from the biosphere. However, this arsenic is released back into the environment if the pH rises, as adsorbed oxyanions become less strongly bound and are displaced by hydroxyl ions. Behaviour of dissolved mercury is similar to that of arsenic but less well understood in these settings. Both arsenic and mercury are readily leached into pH 6 solutions from solid material collected from acid rock drainage sites. These observations suggest that neutralisation of acid rock drainage sites is undesirable in this setting, as arsenic and mercury will become more mobile in the environment. The naturally low pH of 4 to 5 of the forest floor, or even lower pH of natural acid rock drainage, is a preferable management option.

Jan 1, 2003

By P Joyce, D R. Cooke

The Dinkidi Cu-Au porphyry deposit is situated in the Caraballo Range of North Luzon, Philippines. Although comparatively small, Dinkidi has unusually high gold grades with drilling by Climax-Arimco Mining Corporation delineating a 110 Mt orebody at 1.2 g/t gold and 0.5 per cent copper. The magmatic-hydrothermal evolution of Dinkidi records a distinctive switch in mineralisation from an early orthoclase-dominated Au-rich assemblage, typical of alkaline porphyry systems, to a later quartz stockwork Au-Cu rich assemblage typical of most calc-alkaline to shoshonitic porphyry systems. The early orthoclase-dominated stage is associated with the intrusion and crystallisation of a variably-textured clinopyroxene-syenite dyke that contains high-grade (5 - 20 g/t) gold mineralisation. We consider this dyke to be a Cu-Au porphyry analogue to the pegmatites found in granitic systems. Dinkidi is hosted within the Early Miocene Didipio Igneous Complex. This alkaline igneous complex is comprised of early unmineralised gabbros (pyroxene-plagioclase cumulates), clinopyroxenites (pyroxene cummulates), diorites and monzodiorites that have been intruded by a large, weakly mineralised monzonite pluton. The Dinkidi deposit is located at the southern margin of the monzonite pluton. Mineralisation is hosted within a composite monzonite stock. Within the stock, an 800 metres by ~200 metres (plan section) elongate monzonite stock (Tunja Monzonite) predates and hosts the bulk of the Au-Cu mineralisation. This has been intruded by the thin (10 to 30 m wide), highly mineralised variably-textured magnetite- and clinopyroxene- phyric syenite pegmatite (the Balut Dyke). The youngest phases of the composite stock are leucocratic quartz-monzonite porphyry (Quan Porphyry) that grades texturally, in its core, into a post-mineralisation crystal-crowded quartz-syenite (Bufu Felsite). The late-stage Bufu Felsite is inferred to be the source of much of the Cu-Au mineralisation. The Didipio Igneous Complex has intruded a sequence of Late Oligocene alkaline andesitic lavas and volcaniclastics and overlying potassic dacitic lavas. Whole rock geochemical analyses indicate that the intrusions and the potassic dacite lavas in the surrounding region are co-magmatic. Five main stages of hydrothermal activity are recorded at Dinkidi. An unmineralised K-silicate (biotite-magnetite) alteration assemblage formed during the intrusion of the Tunja Monzonite stock. The diorites surrounding the stock display intense selectively pervasive biotite and magnetite alteration and are cut by an extensive network of orthoclase veins and monzonite dykes. The orthoclase-dominated assemblages of Stage Two carry substantial high-grade Au mineralisation and are associated with the intrusion of the Balut Dyke. The emplacement of this unusual dyke is associated with emplacement of pegmatitic clinopyroxene-orthoclase-magnetite¦sulphide dykes, localised orthoclase flooding along the margins of the dyke, and subsequent emplacement of an extensive orthoclase-actinolite-bornite¦chalcopyrite-fluorite stock-work, and development of widespread selectively pervasive actinolite alteration. The main stage of Au-Cu mineralisation at Dinkidi is intimately associated with the intrusion and initial crystallisation of the leuco-monzonite porphyry (Quan Porphyry) and emplacement of a quartz stockwork followed by carbonate-sulphide deposition and intense vein-related sericite and carbonate alteration assemblages. The quartz stockwork formed synchronous with the deposition of the æBugoy QuartzoliteÆ, a very coarse grained mosaic of quartz-orthoclase-perthite along the walls and top of the crystallising intrusion. Stage 3 was terminated by crystallisation of the distinctively vuggy Bufu quartz-syenite phase in the core of the intrusive, with associated antiperthite veins, and the subsequent explosive brecciation of the roof of the intrusion, forming a quartz-fragment breccia from the Bugoy Quartzolite. Retrograde metasomatism during Stage Four was intimately associated with the emplacement of extensive, late-stage carbonate, silica and zeolite veins and widespread selectively pervasive carbonate alteration. The last hydrothermal stage at Dinkidi, Stage 5, is comprised of strong selectively pervasive clay alteration and is associated with fault-related brecciation of the Dinkidi stock.

Jan 1, 1999

The Mineral Research Centre is located at Perth in the suburb of Waterford, adjacent to Curtin University of Technology and within a Technology Precinct which includes Technology Park. The Centre, constructed by the WA Government at a cost of $16 million and occupied in late-1994, comprises three separate buildings housing the CSIRO Division of Minerals, Curtin University's School of Chemical Engineering and the Mineral Processing Laboratory of the Department of Minerals and Energy. The emphasis on R&D at the Centre is primarily in hydrometallurgy as a result of staff expertise, extensive bench and pilot-scale facilities, track record with the industry and, very importantly, two of the occupiers being partners in the AJ Parker Cooperative Research Centre for Hydrometallurgy. Staff in the Centre have a long involvement with R&D agencies such as AMIRA and MERIWA. The hydrometallurgical focus of the Centre complements that of pyrometallurgy at the GK Williams CRC in Melbourne and the Centre for Mining Technology and Equipment in Brisbane, to ensure that the mineral processing industry in Australia has access to a complete range of expertise and facilities to serve its needs.

Jan 1, 1996

Aspiring to be excellent makes you a good leader as it shows a capability for strategic thought, defining and implementing a vision, making a job easier, more efficient and effective. Every great business leader can generate additional revenue or cost savings for their company. Becoming excellent requires the desire and action to follow it through. There are many established methods of excellence: benchmarking, target setting, supply chain and market analysis, employee suggestions and knowledge sharing forums. In BHP Billiton, practices benchmarking is a key tool in generating improvements for functional areas such as processing, mine operations and mine planning. Practices Benchmarking involves organisational and technical questions that allow the site to self-assess their maturity and generate a prioritised improvement path. Not only does it benchmark and identify gaps, but the approach also facilitates networking, education and team building. For new leaders it is important to remember that you are not alone. Chances are your problem has been solved before. Networks û internal, external, formal and informal can get you started and often save you time and effort. Any leader can achieve success in excellence through a proper process of problem formulation, data and analysis. Again, using key players can make the process more effective. It is important to remember that the people side of the solution is the key to success and that monitoring will ensure the solution will work. In the words of BHP BillitionÆs CEO, Chip Goodyear: Excellence is a mind set. ItÆs something that comes when people get rewarded forthinking outside the box and applying their skill and knowledge. It happens, not in$50 million chunks, but in hundred thousand and million and $2 million chunks.When you get 35 000 people thinking that way, then youÆve really got somethinggoing.

Jan 1, 2005

By V A. Diemar

The Chatree Gold Project represents a greenfields discovery of metallurgically clean shallow gold mineralisation in a logistically simple terrain. Total Measured, Indicated and Inferred Resources are currently 31 tonnes of gold and 160 tonnes of silver. Gold occurs in an adularia-sericite epithermal system within quartz-calcite-adularia veins, breccias and stockworks. Host rocks are volcanic arc porphyritic latite-trachyte flows, their pyroclastic equivalents and volcaniclastics of upper Permian to upper Triassic age. The mineralisation was deposited in dilated zones during repeated reactivation of pre-existing structures. To-date five mineralised prospects have been defined by drilling with three reaching JORC Code Mineral Resources status. The project is in its definitive feasibility stage and is anticipated to be in construction during 2000.

Jan 1, 1999

By S Saydam

Professional engineers need to be able to apply university learning to practice. In particular, they have to take responsibility for interactions between technical systems and the complex social environments in which they operate. The most effective way of building this competency is through active experiential learning. We have been developing an advanced educational integrated simulation system to provide mining engineering students with an interactive and immersive learning experience that is not otherwise possible. This will give students an authentic experience in working with industry software packages, while also contextualising the learning in terms of the broader and longer-term impact of technical decisions. We have been piloting the system, in undergraduate courses in order to establish its effectiveness in building systems thinking competencies for mining engineering. For postgraduate students and professionals, the same tools and methods can support studies of more challenging and complex scenarios where mining engineers have to place their decisions within complex global industry contexts.

Nov 22, 2011

By O N. Antzutkin, W Forsling, K J. Pike an

The adsorption mechanism of three different O,OÆ-di-alkyl-dithiophosphate (dtp) collectors, K[S2P(OR)2] with R = Et, i-Bu and i-Amyl, on the surface of synthetic chalcocite (Cu2S) was studied by means of solid-state 31P CP/MAS NMR spectroscopy. The morphology changes on the conditioned Cu2S surfaces, in the collector concentration range 0.1 - 10 mM, were also monitored with scanning electron microscope (SEM). In order to assign Cu(I)-dtp species on the surface of Cu2S, the corresponding bulk Cu(I)-dtp compounds, which are clusters of the monovalent copper containing either Cu6(antiprismatic) or Cu8(cubic) cores, were synthesised, and characterised by means of solid-state 31P CP/MAS and static 65Cu NMR. Further investigations on the crystal habits of the bulk systems were carried out by powder x-ray diffraction and SEM. A comparative analysis of the 31P chemical shift and chemical shift anisotropy (CSA) data estimated from the experimental NMR spectra of the polycrystalline bulk Cu(I) dialkyldithiophosphate complexes was used for assigning the 31P resonance lines in the NMR spectra of the collector treated Cu2S powder samples. The species formed on the synthetic Cu2S surfaces were assigned to polycrystalline phases of: Cu6L6 with L = Et2dtpû, Cu6L6 and Cu8L6(S) with L = i-Bu2dtpû, and Cu8L6(S) with L = i-Amyl2dtpû. A heterophase autocatalytic step process of both formation and growth of solid CuxLy (L = R2dtp, x = 6 or 8 and y = 6) complexes on the collector treated Cu2S surface is proposed. A possible role of the oxidised form of dithiophosphate collectors, bis[di-alkyl-thiophosphoryl]-disulfane (disulfide), is discussed in terms of a specific self-redox reaction. The second order quadrupolar lineshapes in 65Cu NMR spectra were simulated and the interaction parameters, CQ and hQ, for the bulk dialkyldithiophosphato-copper(I) complexes were obtained.

Jan 1, 2005

By H Park, D J. Holland, L Wang, Y Matviychuk, Y Lee

Reuse of process water in mineral and coal flotation plants is widespread to effectively reduce freshwater consumption. However, the accumulation of the frother in the recycled process water is a growing problem as high remnant frother concentration often leads to undesirable overfrothing issues throughout the plants. Various approaches have been proposed by others to measure frother concentration, but none of them is used in flotation practice owing to the requirement of timeconsuming sample preparation steps and/or specialist training to operate and maintain. There is a pressing need for the development of a simple and fast frother concentration measuring technique to avoid overfrothing issues and to optimise the flotation process. The present paper presents two promising approaches to measuring frother concentration online. The first approach measures the concentration of alcohol type frothers based on the host-guest interactions between frother molecules and a formulated liquid. This method is simple and fast as it only requires mixing the formulated liquid with the water sample for up to one minute. The potential of this approach was demonstrated by determination of the residual MIBC concentrations at different locations across a coal flotation plant. The second approach measures frother concentration using a solid-phase extraction (SPE) process and a cryogen-free benchtop NMR spectrometer. Using this approach, both alcohol type and polyglycol type frother solutions can be analysed for concentration determination within 30 minutes. It has also been demonstrated that the concentration of individual frothers in a frother blend (ie MIBC and PPG425 in water) can be accurately analysed even in the presence of background chemicals. This technique has otential for real-time measurement of frother concentration as the whole process can be fully automated.

Aug 24, 2022