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By G W. Swana

Elastoplastic parameter is a parameter that describe how much materials behave elastically up to certain stress states and plastically thereafter (Hudson and Harrison, 1997). In the continuum analysis, two main parameters of the elastoplastic parameter are modulus elasticity and Poisson’s ratio. In the slope, elastoplastic parameter holds the main role for stability related to deformation in ductile type of rock. There’s a limitation to determine elastic or plastic deformation at the field for ductile rock type. Field manifestation commonly showed that there was no accumulation zone during and after the sliding failure mechanism, in other hand, at the research area, manifestation of deformation at the toe of slope only indicated by bulging shape. This paper will focus at the sliding failure occurred at Coal mining Pit Y owned by Arutmin Indonesia, which according to failure investigation report similar with the condition described above. This paper also will be based on two hypotheses, first hypothesis is claystone rock mass has not been reached plastic deformation yet and the second hypothesis is there is a chance that elastoplastic parameter of the rock mass has been changed during the deformation/sliding failure process. Research method of this paper are back analysis using probabilistic analysis in Finite Element Method (FEM), which conducted before and after failure. Then, the result of the displacement or deformation of the analysis will be checked with the actual deformation shape. Meanwhile, the change of the elastoplastic parameter will be analysed and interpreted. This paper hopefully able to be developed to study about elastoplastic behaviour of rock mass in actual condition and the influence of another uncertainty factor which determine the slope stability.

Nov 29, 2022

By E Niva

The IsaMillÖ is challenging the way that plants are designed and operated. This paper challenges existing designs of concentrator flow sheets, particularly focusing on magnetite circuits.   From what has started out as a small scale ultra fine grinding mill in the pharmaceutical and pigment industries, it has been redesigned and improved upon for mineral processing, and has been the mainstay of fine grinding applications for over ten years. These applications have required energy efficient grinding to succeed, and have been predominately in the base metals industry.   Further development of the IsaMillÖ has now resulted in the machines being able to treat larger tonnages, with higher capacity motors. This development, along with the introduction of purpose designed ceramic media, has allowed the mill to treat courser feed sizes. At the same time, the mill still offers highly efficient grinding, and has enabled it to be operated in coarser tertiary and secondary grinding applications.   The acceptance of the mill in coarser applications, predominately in base metals and PGM applications, has enabled the IsaMillÖ to be a serious contender for beneficiation in other minerals. One such application is the potential for IsaMillsÖ to be part of magnetite flow sheets, which are being considered in Australia to meet the growing iron demand of China. The high energy efficiency of the IsaMillÖ compared to conventional technologies, as well as the smaller infrastructure requirements, provides a great opportunity to reduce the power intensity of magnetite circuits.   This paper will examine the use of IsaMillÖ technology in conventional grinding applications, including recent testwork in a primary grinding base metal circuit, as well as testwork on magnetite ore comparing a lab scale IsaMillÖ with a lab scale Tower Mill.   The growing demand for minerals over the next decade, coupled with higher energy cost, will result in energy efficient technology, such as the IsaMillÖ, being included in standard circuit design.

Jan 1, 2008

By Snowden D. V, Standing C. A, Ryba A, Bywater A

McKinnons open pit gold mine, located within the Cobar Basin in New South Wales, is characterised by complex mineralisation controlled by the intersection of steep faults in the hinge zone of an anticline. Resource estimation using indicator variography and indicator kriging was based on RC drilling on 25 in sections together with grade control RC drilling on 12 in by 12 in and 6 m by 6 in patterns. Rigorous sampling and checking procedures were used to verify the reliability of the drill hole data. Blast hole data was used to assist grade control in defining ore block boundaries.

Jan 1, 1997

By P de Caritat, A Davidson, A Mann

Top outlet sediments from the National Geochemical Survey of Australia have been extracted by a partial extraction method for over 50 elements including gold. The partial extraction results from this low-density survey show discrete coherent anomalies for Au in the vicinity of many of AustraliaÆs known goldfields, and in the vicinity of some minor gold occurrences. In several instances catchment outlet anomalies for Au have been recorded from areas not known to contain significant economic gold. Several large economic goldfields are shown to not produce anomalies in catchment outlet samples. A survey of overbank samples in the Swan Avon catchment of Western Australia at double the sampling density shows that low level anomalies (>1 ppb) can be traced back to source using overbank sediments. Follow-up of one of the Au anomalies at Kent River in previously regarded non-auriferous terrain (western Albany-Fraser Belt) indicates a non-economic, but perhaps geochemically significant, Au anomaly with associated pathfinders including palladium. This may indicate that further exploration of the western part of Albany Fraser Belt for Au is warranted. The combination of catchment overbank samples and partial analysis technique has been shown to be effective at locating the source of gold anomalies from initial low-density continental and regional surveys.CITATION:Mann, A, Davidson, A and de Caritat, P, 2013. High resolution soil geochemistry for gold exploration at the continental, regional and prospect scale, in Proceedings World Gold 2013 , pp 167-174 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By D Frost, G Harbort, T Lipiec, N Deonarain

"The use of flotation columns has remained a contentious issue among mill operators. There are those who consider them an essential part of any mineral processing operation, while others consider them a necessary evil, which should only be installed if there is no alternative. Lastly, there are those who believe they should not be installed, no matter how great the perceived benefit.This paper provides an analysis of over 4000 installed flotation columns, contained in the Amec Foster Wheeler flotation database. Changing trends in column flotation use by type, commodity and geographical region are discussed. The effect of changing commodity prices and the China ‘phenomenon’ are reviewed. Special reference is made to the changing face of column flotation in Australia.Of note is the fact that after falling to a 20 year low in installed flotation column capacity in 2014, flotation columns during 2015 went through a resurgence in popularity. This resurgence was in direct contradiction to depressed metal prices and was driven by brownfield optimisations to reduce off-site costs, particularly in base metals. A case study is presented comparing the benefits of column flotation at high commodity prices with low commodity prices.Citation:Harbort, G, Deonarain, N, Frost, D, Lipiec, T and David, D, 2016. Changing Trends in Column Flotation Use - Their Impact for Australian Mill Operators, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 93–104 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By V Matousek, A Sellgren, R Visintainer, G McCall

A 4-component model for settling slurry pipe flow has been previously described by Wilson et al (2006) and Sellgren et al (2014) to predict pipeline friction loss (hydraulic pressure gradient) over a range of slurry compositions: from fine to coarse particle size, narrow to broad particle size distribution, and low to high solids concentration. The method applies a weighted average of established pipeline models for various settling slurry flow regimes, according to the volume fraction of solids falling within the applicable size range for each model. Further development of the model was undertaken by Visintainer et al (2017a, 2017b), based on a comprehensive set of laboratory tests in 203 mm (8 inch) and 103 mm (4 inch) pipelines, and it was also adapted to the modelling of slurry pump performance derates. However, this work was all performed with solids having a specific gravity near 2.65, as is typical for many mineral processing and dredging applications. The goal of the present work is to test the applicability of these models for settling slurries having a higher solids specific gravity, as may often be seen in the mineral processing of iron ore deposits. To that end, a test program was carried out in a 103 mm (4 inch) pipe loop using various compositions of an iron ore product having a solids specific gravity of 4.75 and containing both coarse and fine solids. By screening and flushing operations, a range of particle size distributions were created having different proportions of the coarse and fine elements. In all, 19 tests were performed with d50 particle sizes ranging from 50 μm to 3.2 mm and delivered solids concentrations from 10 per cent to 43 per cent by volume. Particle size distributions varied from very narrow to very broad, with d85/d50 ratios ranging from 1.75 to 26. Pipeline pressure gradient and pump performance data were collected and used to test the applicability of the previously developed 4- component models and to propose improvements to the models for the handling of high-density solids.

Nov 8, 2021

By S Bluhm, L van den Berg

In planning mine ventilation systems, heat issues are normally associated with deep-level mines where auto-compression and virgin rock temperatures play a major role. However, a number of mines suffer from high ambient temperatures and humidity, very steep virgin rock temperature gradients and an influx of hot groundwater. Mines in Australia and, particularly, South-East Asia have to deal with these environmental conditions, both in the operational and planning phases. These operations normally have to take heat into consideration during the planning stages at much shallower depths. In high rainfall regions, the water table is saturated and groundwater flow rates are particularly high, which add significant water heat load potential to the mine ventilation system.This paper considers the ventilation challenges associated with hot groundwater conditions in mechanised mines. The paper is based on specific project experience gained from a number of projects in the United States, Australia and South-East Asia and draws on data from mines that experience hot groundwater conditions. For one site, actual decline temperature survey measurements, modelling techniques, management strategies and design considerations are presented.CITATION:Van den Berg, L and Bluhm, S, 2015. Ventilation planning considerations when dealing with hot groundwater, in Proceedings The Australian Mine Ventilation Conference, pp 211–218 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By G Lumley

Gold miners have been underperforming the price of gold for a number of years. So why has the æmarketÆ undervalued our gold miners relative to what they have been mining? The low valuation ascribed to gold mining companies is largely attributable to their profit performance. In the period since 2006 the price of gold in A$ has risen about $900/oz, but the real cash margin (operating cash costs + cost of finding and/or acquiring deposits + the cost of bringing them into production) has only risen about A$100. Rising operating costs are a major part of this reduction in real margin. Energy and labour costs have risen more than the inflation rates across a number of countries as have taxes, royalties, etc. There are however, more significant contributors to the rising cost base. Firstly, in 2006 the average gold grade was 2.0 g/t; today it is 1.3 g/t. Secondly, strip ratios (for surface mines) have increased by 19 per cent during this time. Open cut mining equipment unit output across the world has dropped by 26 per cent during 2006 - 2012. Finally, costs have risen by 55 per cent during this time period. Consequently, there is now 3.8 times more mining cost required to produce an ounce of gold from surface mines compared with 2006. The decline in gold grade looks to be a permanent trend as does increasing strip ratio if output is to be maintained. Costs will continue to rise although cost control will be necessary. Reversing the decline in equipment performance and closing the gap between median and best practice provides the hope for a sustainable reversal of cost increases. The current gap between best practice and median performance has grown to 112 per cent for mining trucks, 168 per cent for excavators and 169 per cent for front end loaders. Closing this gap is the potential for a more profitable future. For most gold mining companies improving mining efficiency is not an option; it is an imperative.CITATION:Lumley, G, 2013. How many gold mines will inefficiency kill?, in Proceedings World Gold 2013 , pp 267-276 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By F van de Venter, J Monama, T Kale

For a multitude of years fine iron ore, -1 mm, across the world has been deposited as discard material in tailings facilities. This contributes to environmental problems, decreases plant yield and increases the cost of processing. Fine iron ore recovery processes are often deemed unfeasible or uneconomical, due to the complexity of the reclamation thereof in comparison with high-grade ores. However, recent advances in the recovery of fine iron ore using the Optima Classifier® has shown great promise. The Optima Classifier® is a new hindered settling separator that makes use of an upward current of water for density separation. It’s unique design combines three different separating zones for increased efficiency and recovery. In this study the potential of the Optima Classifier® to produce a +63 per cent Fe concentrate from -1 mm feed material was evaluated from a standalone and process perspective. It was found that a +63 per cent Fe product can be produced from a single stage, using the Optima Classifier®. Fine iron ore feed with an average head grade of 50 per cent Fe was upgraded to average concentrate grades of 63.2 per cent Fe. Displaying upgrade ratios of up to 1.26 in a single stage. A three-stage, rougher, cleaner and scavenger system did however show the best performance with recoveries of up to 70 per cent, yielding 56 per cent of a 63 per cent Fe product. Furthermore, the dewatering of the product and tailings was evaluated using the UltraG ultra-fine dewatering screen ensuring dry, stackable material. The tailings could be used in codisposal, while loads on thickeners and filter presses are significantly reduced. The high throughput of the Optima Classifier® ensures a small plant footprint, minimal civil and structural requirements and low operating utility consumption such as electricity, minimising the carbon footprint of a fines beneficiation plant. The Optima Classifier® in combination with the UltraG dewatering technology has provided a platform for economical recovery of fine iron ore, both current arising and historical. Providing opportunity to lower plant operating costs, reduce environmental liability of tailings facilities and increasing immediate process water recovery

Sep 18, 2023

By A D. Pradana, D R. Pradana, Y H. Putra, Z Zulhan, T Hidayat

The high temperature processing of nickel laterite ore is currently dominated by the Rotary Kiln- Electric Furnace (RKEF) technology. The ratio of SiO2/MgO (S/M) in the ore is one of the critical parameters that determines the success of the RKEF process. Incompatible S/M ratios in the ore can cause aggressive chemical interaction between the slag and MgO refractory. The slag-refractory interaction at conditions relevant to nickel laterite ore smelting was investigated in the present study. Synthetic mixtures representing the slag compositions of nickel laterite ore smelting were prepared by mixing MgO, SiO2, Al2O3, CaO, Fe2O3, and Fe and heating the mixtures in steel containers at 1300°C under an argon atmosphere for 3 hrs. Pure MgO crucible were used as containment material in the melting process of the mixtures to represent the MgO refractory. The kinetics of the slagrefractory reaction were investigated using samples with selected initial S/M ratios of 2.0 and 3.0 (wt/wt) (with constant CaO = 3 wt per cent, Al2O3 = 5 wt per cent, FeO = 10 wt per cent) by performing melting at 1500°C in MgO crucibles for 5, 30, and 120 mins under an argon atmosphere. The effect of the S/M ratio in slag on the slag-refractory interaction was also investigated by performing melting of mixtures with different initial S/M ratios of 1.75, 2.0, 2.5, and 3.0 (wt/wt) in MgO crucibles at 1500°C for 120 mins under an argon atmosphere. After the melting process, each sample was quenched in water, mounted in resin, ground, polished, and coated. The interaction between the slags and MgO refractory was then evaluated by analysing the polished samples using a scanning electron microscope equipped with an energy dispersive spectroscopy (SEM-EDS). Thermodynamic simulations using FactSage™ 8.0 thermochemical software were performed based on the experimental slag compositions, refractory, and conditions to support the evaluation process. The results show that a higher S/M ratio in slag leads to a higher tendency for the refractory component to dissolve into the slag. A higher S/M ratio in slag also leads to an increasing extent of solid-state diffusion of iron oxide into the remaining refractory grains. The dissolution of MgO into the slag is rapid; the MgO concentration in the final slag increased by 2.4 wt per cent and 5.7 wt per cent at initial S/M ratios of 2.0 and 3.0 wt/wt, respectively, within 5 and 30 mins of the melting process.

Aug 21, 2024

By M Z. Abzalov

Drilling mineral sand deposits has specific challenges, which are different from drilling hard rock deposits: Drilled sequences are represented by non-consolidated free-flowing sands to semi-consolidated clayey sands and indurated layers. Valuable heavy minerals (ilmenite, rutile, zircon, leucoxene) have an average density of 4.6 g/cm3, which is significantly heavier than the hosting sand matrix; mainly represented by quartz (density = 2.6 g/cm3). The large difference in the mineral densities can result in sample segregation in the drilling rods and capturing devices causing biased composition of the recovered samples. The drilled strata can contain beds of consolidated sediments, hard pan lenses and concretions. Therefore, chosen drilling equipment should be flexible and permit a switch from drilling the free-flowing sands to hard rock drilling. Thickness of the sand hosted mineralisation varies from several metres to more than 170 m. Mineralisation is distributed above and below the water table. Evaluation of the mineral sands deposits is based on hundreds of drill holes and many thousands of samples, therefore drilling methods should be fast and cost effective. The drilling methods commonly used for mineral sand deposit evaluation, include aircore, triple tube diamond and sonic; including its variants, such as vibrocore drilling technique. The ability of the studied drilling techniques to properly address the above listed challenges in mineral sand deposits, whilst maximising the quality of the obtained samples has been compared in three deposits: Corridor Sands (Mozambique), Richards Bay (Republic of South Africa) and Fort-Dauphin (Madagascar).This study has shown that aircore samples tend to be negatively grade biased, underestimating the heavy minerals content, in particular when drilled intervals are located below the water table. Triple tube diamond core method can produce non-biased samples. However, results can be marred by incorrectly chosen drilling mud. Sonic drilling is a relatively new technique based on a high frequency vibratory technology. It is the only production drilling technique that allows a continuous relatively undisturbed sample of unlithified sands to be obtained. The main limitations of this technology preventing its wider use for developing mineral sand resources are the relatively high drilling costs, in particular when the depth of drilling exceeds 100 m, and speed of drilling advance.

Oct 5, 2011

By V Shrotri L Muhmood, P Gandhre

The current work deals with the measurement of some thermophysical properties of Ca(NO3)2 based ternary nitrate molten salts as HTF (heat transfer fluid) / TES (Thermal Energy Storage) material for CSP (Concentrating solar power) plants. The density and viscosity of different compositions of the ternary salt mixture containing Ca(NO3)2, NaNO3 and KNO3 close to the liquidus has been experimentally measured. An attempt has also been made to measure the melting point of the salt using the cooling curve technique as well as Differential Scanning Calorimetry (DSC). Thermogravimetric analysis has also been performed to estimate the peak operating temperature of the salt. Compatibility of suitable pipe material (SS304) with molten salt has also been discussed. The salt mixture proves to be a viable alternative to the already existing HTFs like Therminol VP-1 (organic oil) or Solar Salt® in regards to its lower melting point, wider operating range, low cost, nontoxicity, sufficiently high density and comparable viscosity.

Jun 19, 2024

By S McKnight, L Koroznikova, S Hall

Mineral sands represent an important new resource being developed in the Murray Basin, including parts of western Victoria. This paper will outline a simple methodology for mineral sands characterisation, developed as part of the AMIRA-managed project P777 æThe Development of Heavy Suspension Techniques for High Density Separations (Replacement of ClericiÆs Solution)Æ. This project is currently sponsored by three multinational mining companies (De Beers Consolidated Mines, Iluka Resources Limited and Rio Tinto Limited) and is developing an innovative laboratory mineral characterisation procedure that will allow the replacement of the currently employed highly-toxic chemicals.Mineral sand resources almost always contain more than one valuable (and relatively heavy) mineral. Titanium minerals are found with a large range of titanium contents, giving rise to density variation and often subjective mineralogical descriptions. Companies tend to rely on laboratory heavy liquid separation in the evaluation of samples arising from exploration, mining or metallurgical processes. Unfortunately, there are only a limited number of high density (æheavyÆ) liquids and these tend to be more toxic as their density increases. Low-toxicity inorganic solutions, based on tungsten compounds, have been developed that can be utilised at relative densities (RD) up to 3.0. However, beyond this value currently only organic liquids can be used. Diiodomethane (methylene iodide) having a relative density of 3.31 is commonly used; however, this presents significant health and safety hazards. Mixtures of thallium formate and thallium malonate were found in the early 1900s by Clerici to provide liquids having specific gravities between 4.0 and 5.0, hence æClericiÆs solutionÆ. For the characterisation of the heavy components of mineral sand deposits (eg anatase sg 3.9, rutile sg 4.2, ilmenite sg 4.4 û 4.7 and zircon sg 4.6 û 4.8) there is currently no heavy liquid alternative to ClericiÆs solution. ClericiÆs solution is highly toxic and testing is now conducted by very few laboratories worldwide with costs reflecting the chemical costs (though extensive efforts are made to recover and reuse the liquid, plus the requirement of its removal from the mineral samples), the infrastructure costs and health and safety regimes (eg blood testing of exposed staff, inventory management). A simple laboratory technique of density fractionation is being developed, employing suspensions of fine tungsten carbide particles in lithium heteropolytungstate (LST) solutions, that can replace ClericiÆs solution in the evaluation of fine mineral sands samples (eg -250+150 microns). The developing methodology that can achieve low-cost, low-toxic separations at relative densities above 5.0 will be outlined and the comparison of results with ClericiÆs solution presented.

Jan 1, 2006

By S Hapugoda, J R. Manuel, X Cao, B D. McDonald, N A. Ware, L Lu

Roy Hill is a large iron ore mining, processing, railing and port operation in the Pilbara region of Western Australia. Since delivering its first shipments to customers in December 2015, Roy Hill has quickly achieved a 60 Mtpa production rate of lump and fines products. The process plant, principally consisting of wet scrubbing, screening and de-sanding unit processes, was expanded from early 2020 to include operation of a Wet High Intensity Magnetic Separation (WHIMS) Plant. The WHIMS Plant treats tailings to recover approximately 4 Mtpa of ultra-fine (nominally -150 μm) high-grade hematitic concentrate which, after dewatering, is blended into the fines product. Unlike typical hematite concentrates, which consist largely of dense particles with smooth surfaces, the WHIMS concentrate is characterised by very finely microporous hematitic/goethitic particles, reflecting the overall characteristics of the Roy Hill deposit. Detailed test work has been conducted in collaboration with CSIRO to characterise the WHIMS concentrate in terms of its physical and mineralogical properties, and to determine its influence on the granulation and sintering performance of Roy Hill fines – from fundamental/lab-scale and sinterpot perspectives. The results demonstrate that blending of the high-grade hematitic Roy Hill WHIMS concentrate into the fines product can maintain overall sinter quality and positively influence granulation and sinter melt formation, as well as Fe grade.

Nov 8, 2021

By L Lorenzen, H Muller, L Bernard

Australian companies and consultants are becoming ever more involved in projects in African, South American, East European and Middle Eastern countries. However, significant differences in culture and approach to projects sometimes make these projects challenging for reasons that are not purely technical. Often the challenges are rather related to how the project owner and local authorities perceive the reality. These perceptions and sometimes unrealistic expectations regarding project costs and potential outcomes need to be addressed by the æWesternÆ project developer and consultant.This paper will discuss the specific experience of Snowden in studies commissioned by companies from such countries for the development of very large, low-grade gold deposits in some of the most inhospitable areas in the world. The paper will further review similar projects undertaken in other ænew worldÆ countries and compare these to the initial Snowden experience.As the process operating costs of operations in many of these countries are extremely competitive when compared to the typical Australian operating costs, the paper will review the operating costs and the factors which may be pertinent to a large project of this nature, both in the Australian and the ænew worldÆ context. Will Australian-based operations be able to compete in the global gold market when the gold price softens again, as it will do at some stage in the possibly not-so-distant future?CITATION:Muller, H, Lorenzen, L and Bernard, L, 2013. Challenges of developing low-grade deposits in ænew worldÆ countries from a mining consultantÆs perspective, in Proceedings World Gold 2013 , pp 307-314 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By M Schaffer, T Kewe, N Moffatt

Porgera mine is 95 per cent owned by Barrick Gold Corporation. It is located at an altitude of 2200–2700 m above sea level in the Enga province of Papua New Guinea and produces approximately 460 000 oz per annum with a proven and probable reserve of 6.2 Moz. The refractory ore is ground in a conventional semi-autogenous grinding and ball mill circuit. After the gravity gold is recovered, the slurry is floated, oxidised in the autoclaves and then leached. This paper will focus on the flotation circuit and the recent upgrade of the control system. The five interdependent flotation circuits were challenging for operations to control as they dealt with variable grade, throughput and circulating loads, as well as the physical limitations of the equipment. With the installation of 18 Portage Froth Characterization® (PFC) cameras, the plant’s operation has been converted from a level-control based strategy that was focused on individual cells to one that targets grade and recovery control across the entire circuit. Variability in feed and the corresponding launder issues were addressed with a unique site initiative of deflector plates to indicate filling level. Non-linear closed loop control was implemented directly in the DeltaV Distributed Control System (DCS) using Portage Advantage Regulatory Control (PARC) algorithms and optimised with AwaRE advanced controllers. The most noticeable benefits achieved with the upgrade include improved flotation gold recovery, consistent flotation sulfur grade and autoclave performance. Correspondingly, there was a significant drop in boiler diesel fuel usage and launder overflow conditions.CITATION:Kewe, T, Moffatt, N and Schaffer, M, 2014. Porgera flotation circuit upgrade and expert system installation, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 345–356 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By M Castello, P Bouchard, M Sabsabi, A Blouin, B Nguegang Kamwa, M Constantin, K Fytas, M Laflamme, K Rifai, F Vidal

Canada’s Quebec province operates 26 metal mines, 19 of which are producing gold and generating over C$1.8 billion (US$1.3 billion) annually. In all those mines, numerous samples of rock are collected and analysed daily in laboratories in order to determine their gold content. However, laboratory results are generally available within 48 hours of sampling (depending on the number of samples received by the laboratory and the priority of the results), thus potentially slowing down mining activities. In an attempt to find a solution for delayed laboratory results, Laval University, in partnership with the National Research Council Canada (NRC), the National Institute for Scientific Research (INRS) and four mining companies (Agnico Eagle, Canadian Malartic, Hecla Québec and Iamgold) have launched the Laser-Induced Breakdown Spectroscopy (LIBS) project for in situ real-time mining sample analysis. This work aims to minimise the amount of LIBS point sampling necessary to be representative of a full scan of the analysed area. Eight sampling patterns are investigated. A statistical analysis of the data was performed by varying the pattern steps. Results show that two of the patterns, 1 and 5 (single diagonal crossing the stratification of the samples with opposite slopes) minimise the amount of point sampling while remaining representative. The most successful results are obtained from steps which are greater than 6. In terms of the type of material, pattern 5 and steps 9 are better for core sampling, while pattern 1 and steps 8 are better for rock sampling. The geological explanation for these results is the heterogeneous distribution of gold in the sample which seems to be more homogeneous in the rocks than in the core sample due to the small rock size. In terms of the mineralisation, pattern 5 is better for mixed sulfides and quartz veins, and steps 8 and 9 are better for quartz veins.CITATION:Nguegang Kamwa, B, Rifai, K, Laflamme, M, Constantin, M, Castello, M, Vidal, F, Bouchard, P, Fytas, K, Blouin, A and Sabsabi, M, 2017. Sampling strategy by statistical analyses of LIBS data in the context of a portable gold analyser, in Proceedings Tenth International Mining Geology Conference 2017, pp 221–232 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By F Carrick, W A. Ellis, D R. Mulligan, S I. FitzGibbon

"One of the major environmental impacts of mining is the destruction of habitat. The koala (Phascolarctos cinereus) is an iconic Australian marsupial that has been severely affected by land clearing and its decline is continuing. This has placed pressure upon mining companies and government agencies to ensure koalas are managed throughout the life-of-mines - from land clearing through to rehabilitation of post-mining landscapes. This paper reports on the æKoala VentureÆ research partnership between The University of Queensland and Rio Tinto. As part of the Koala Venture program we examined koala use of two types of restored environments: rehabilitated mined land (20 sites) natural regrowth forests (six sites), at Blair Athol Coal Mine in Central Queensland, Australia. Searches for koala scats revealed evidence of koalas in ten per cent of rehabilitated sites (2/20) and 33 per cent of natural regrowth sites (2/6). Two factors were identified as being of greatest importance in facilitating koala recolonisation of restored habitats. Firstly, all recolonised sites were located close to native forest occupied by koalas (mean 135 m ¦ 52). Proximity to source animals is considered crucial to recolonisation of suitably restored habitats. Secondly, three of the four recolonised sites were dominated by koala food trees, most of which were large enough to be utilised by koalas. Availability of suitably abundant food resources is, therefore, also considered crucial. The requirement for these two factors, in combination, is highlighted by the absence of koalas at several sites that contained abundant food trees, but that were distal to areas with source animals, and vice-versa.Our research demonstrates the enormous potential for restoration of wildlife habitat on post-mining lands, even for species with specific requirements such as the koala. Consideration of the ecological requirements of wildlife during rehabilitation planning is critical to enhancing the likelihood of recolonisation.CITATION:FitzGibbon, S I, Ellis, W A, Mulligan, D R and Carrick, F, 2012. Rehabilitating post-mining landscapes for wildlife - A case study from the Koala Venture research program in Central Queensland, in Proceedings Life-of-Mine 2012, pp 319-324 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 10, 2012

By A G. Tomkins

"Approximately 32 per cent of the worldÆs total gold production has come from greenstone belts (Frimmel, 2008). In these regions numerous small to large, quartz vein-associated gold deposits are hosted in metamorphic rocks ranging from lower greenschist to granulite facies. Historical exploration has focused its efforts on rocks of greenschist to lower amphibolite facies because these seem to contain the most deposits. Consequently, these regions are now reaching mature brownfield status, particularly in developed nations, and finding new deposits is becoming progressively more difficult. In comparison, regions of similar tectonic setting, but instead containing high-grade metamorphic rocks of mid-amphibolite to granulite facies, have received little attention because the first explorers found fewer deposits there.However, these regions certainly do contain some very significant gold deposits such as Hemlo in Canada (~684 t Au), Renco in Zimbabwe (~31 t Au mined since 1980), the very profitable Challenger deposit in South Australia (~36 t Au; recovered + reserve + resource), and the most recently discovered Tropicana deposit in Western Australia (~182 t Au; reserve + resource). High-grade metamorphic terrains therefore offer explorationists an excellent opportunity to move onto relatively green fields within developed nations, which carry less risk associated with development. However, explorationists have comparatively little knowledge of the geological controls on gold distribution in high-grade terranes because: industry experience lies in traditional lode-style gold deposits these gold deposits are geologically more complex there has simply been minimal research conducted on these deposits as a holistic group.Furthermore, research conducted in the last five years has shown us that the previous widely accepted model for gold genesis in these terranes, the crustal continuum model, is incorrect. Here, I discuss features from several gold deposits hosted in high-grade metamorphic rocks and use these to define two categories for explorationists to consider: deposits that formed prior to peak metamorphism (metamorphosed gold deposits) deposits that formed well after peak metamorphism (post-metamorphic gold deposits). There are none that have been convincingly shown to have formed during peak metamorphism.CITATION:Tomkins, A G, 2013. Gold deposits in highly metamorphosed terranes, in Proceedings World Gold 2013, pp 23-26 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 26, 2013

By M Scoble, A Ostry, J Shandro

Mining companies are not ill-informed on the topic of community health. There have been a number of research studies that have illuminated community health issues associated with mining, especially in the western Canadian province of British Columbia. However, what is missing amongst the literature is the perspective of mine managers and mining executives on this topic. This is important as mine managers and executives face a number of issues related to community health and are under pressure to consider the topic in more detail. This paper presents results from an exploratory qualitative investigation based on grounded theory research techniques into current community health considerations from the perspectives of mine executives and mine managers working in Western Canada. Interviews were conducted between February and May 2012 with 11 mining versus ten mining executives and managers who represented operating mines or mining umbrella organisations in Western Canada. Participants report on general community health issues that are perceived to be important, the perceived role that the mining sector should play?in contributing to community health and how this differs in Western Canada as compared to locations abroad, and?risks companyÆs face in making community health contributions. This paper concludes by drawing attention to pressing health needs that are present in Northern, rural and Aboriginal populations in Western Canada and provides a platform for future research initiatives focused on improving the health and well-being of communities associated with the mining industry. CITATION:Shandro, J, Scoble, M and Ostry, A, 2012. Community health considerations from mining executives and managers in western Canada, in Proceedings International Mine Management 2012, pp 97-104 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 20, 2012