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By M. Carvalho

The primary motivation underlying the proposal of polygeneration systems for mine sites is to increase the efficient use of natural resources by combining different technologies and energy resources while satisfying energy service demands. For many mineral producers, particularly in Canada?s mining extremes of climate and depth, energy in support of mineral production can be the second largest cost centre after labour. A generic methodology is proposed for the design of energy supply systems in mine sites, based on a search for the minimum discounted cost of energy supplied for all feasible different plant configurations. These configurations can be represented within a connectivity matrix which corresponds to a network representation. A Mixed Integer Programming formulation is set out for the multiperiod synthesis and operational planning problem. This is characterized by i) binary variables for the selection of technologies, ii) integer variables for the determination of the number of units installed, and iii) by continuous variables for the representation of energy and economic flows. Through the integration of particular energy supply strategies matching specific mine circumstances (on-grid, remote, degree days, etc) and consideration of technologies that improve energy efficiency, hitherto not considered new technologies and demand management systems or new perspectives on optimal mine site energy supply can be investigated. Some of these investigations identify the economic conditions through which biomass energy feedstocks should be used, for direct heat production, for gasification and providing for Fischer-Tropsch syndiesel manufacture. As well as integrating demand from mobile diesel-fuelled plant into an optimization procedure that hitherto has only been considered for static energy production and consumption plant, this analysis shows how the techniques can be used to explore economic conditions of threshold prices for biomass (purpose-grown biomass and peat are considered herein) and trucked-in diesel. The methodology also allows for electricity and syngas storage and diesel and biomass bunkering. Within the paper the energy demands for a remote, open pit mining operation located in Northern Ontario are considered as a case study to illustrate the technique and investigations. As expected, for mines close to electricity, natural gas, and diesel distribution infrastructures, the optimal choice is to connect. When a constraint is applied specifying that connection is not possible, as would be for the case exemplified, the optimal choice includes some of the more exotic options for mine site energy supply.

Aug 1, 2013

By R. E. Whitehead

"Abstract - Biotite from aplite that appears to have crystallized simultaneously with disseminated Cu-Mo mineralization at MacLeod Lake in northern Quebec yields K-Ar dates in the range 2032 ± 44 Ma to 2097 ± 47 Ma. The mean value, 2065 Ma, is some 400 Ma younger than the 2485 ± 64 Ma date obtained from a hornblende concentrate separated from a granodiorite sill that is spatially, but apparently not genetically, associated with the disseminated Cu-Mo deposit. The mean biotite date of 2065 Ma at MacLeod Lake, a K-Ar date of 2055 Ma reported from an area 50 km east of MacLeod Lake and published dates of about 2000 Ma for galenas from the Chibougamau Cu-Au ores, suggest a widespread thermal and mineralization event, in that part of the Superior Province east of James Bay, that differs from the common late Archean mineralization that is related to volcanism and metamorphic-intrusive activity.Sommaire - Les datations au K-Ar sur des biotites qui auraient cristallise en même temps que la minéralisation disséminée en Cu et Mo dans une aplite mise en place au Lac MacLeod, au nord du Québec, s'échelonnent entre 2032 ± 44 Ma et 2097 ± 47 Ma. La datation moyenne, soit 2065 Ma, est d'environ 400 Ma plus récente que la datation obtenue pour un concentre de hornblende extrait d'un filon-couche de granodiorite qui est spatialement mais ne serait pas génétiquement associée à la minéralisation disséminée en Cu et Mo. La datation moyenne de la minéralisation au Lac MacLeod, soit 2065 Ma, la dataion au K-Ar à 2055 Ma citée pour une région à 50 km à l'est du Lac MacLeod, de même que les datations d'environ 2000 Ma établies pour des galènes qui se trouvent dans le minerai aurifère et cuprifère à Chibougamau, suggèrent un phénomène thermique répandu qui aurait produit la minéralisation dans cette région à l'est de la Baie James, dans la province du lac Supérieur. Ce phénomène serait diffèrent de celui qui aurait produit la minéralisation répandue d’âge archéen tardif qui elle serait associée à l’activité volcanique et à l‘activité intrusive accompagnée de métamorphisme."

Jan 1, 1992

By Emile D. L. Rienks

We have studied the interaction of NO with the quasi-hexagonally reconstructed Au(100) surface. Using variable temperature scanning tunneling microscopy we have observed formation of the unreconstructed phase of Au(100) after NO exposure. This NO adsorption induced phase transition is observed in a window of temperatures around 170 K. Under the same conditions, CO and O2 cannot drive the phase transition, suggesting weaker interaction. Thermal desorption spectroscopy experiments provide an estimate for the strength of NO chemisorption on Au(100) of 57 ± 4 kJ mol-1.

Oct 1, 2003

Owner?s Team and EPCM ?Teams rolesmay vary to suit the skills available, however the tasksremain the same ?Ensure adequate level of capability in the team ?Large owner?s teams vssmall owner?s teams ?size of owner?s teams can reflect not only the individual level of capability but also the type ofrelationship with the EPCM contractor ?Wholly owned projects vsjoint ventures projects ?Both cases require clear accountabilities and authorities ?Project sponsor should be a senior executive with commercial andtechnical accountability of project outcome ?Project leader should be experienced and have solid leadership capabilities ?Attention should be paid to balancing personality types in an owner?s team

May 1, 2010

By G. Tozsin

A six-stage sequential leaching procedure was used to assess the leachability of heavy metals from waste rock in Antamina Mine. Sequential extractions procedure is well established for fine and small (? 1g) samples. However procedures for coarse and large test samples are lacking. This study presents results of the sequential leaches tests conducted on relatively coarse and large representative samples in terms of the availability and mobility of metals. Selective chemical reagents were used to extract metals from six different fractions where metals released with each subsequent extraction are believed to be bound tighter than those released in prior steps and therefore less likely to be leached.

Aug 1, 2013

By Lee Barbour

Waste-rock piles from metal mining operations are comprised of large surface deposits of unsaturated, coarse-grained soil and rock. The unsaturated condition and heterogeneous, coarsegrained nature of these deposits make them difficult to monitor or characterize. Key parameters that must be evaluated include; volume-mass relationships (e.g. water content, air content, porosity, density, degree of saturation, grain-size), transport properties (e.g. air-permeability, gas diffusion, hydraulic conductivity), geochemistry (e.g. solids, gas, and fluid phases) and soilatmospheric fluxes (water and gas). This paper describes some of the techniques that have been developed to characterize waste rock piles for uranium mines in Northern Saskatchewan. For each technique, the method of measurement is described, and preliminary field data are presented and discussed.

Nov 1, 2002

By J. Paraszczak

Application of teleoperated and automated (or ?autonomous?) mobile equipment in underground metal mines represents a promising avenue for overcoming some of the challenges facing the industry. This paper addresses the overall effectiveness of autonomous loading and haulage equipment compared with conventional human-operated machines. Factors affecting availability, utilization, and production rate are explored, and an emphasis is placed on some problems and risks not present in conventional human-operated systems, as well as on the character and criticality of autonomous equipment. The need for a more in-depth analysis of factors affecting overall autonomous equipment effectiveness is stressed; these factors should be taken into consideration at the stage of feasibility studies. The paper concludes with recommendations and directions for future research.

Aug 1, 2010

By Stuart M. Jones

This paper is derived from a document that compiles autogenous and semi-autogenous mill installations worldwide, through the end of 2010. Updates have been solicited from all major mill manufacturers and most have responded. A review of AG/SAG mills sold to date and in the last five years indicates that the AG/SAG mill market is very healthy and the trend is larger diameter mills with high diameter-to-length ratios. Ring motors (gearless) are the preferred drives for large mills even though the power transmitted through a gear drive is expected to near 11,000 kW per pinion in the near future.

Aug 1, 2010

By R. A. Nemchek

Over the years, concentrator plant design has evolved from a large number of small grinding mills to a small number of large mills. In many cases, all of the tonnage runs through a single mill (typically a large SAG mill), so that the plant’s performance hinges on the productivity of this one machine. Industry specifications attempt to address the critical nature of today’s grinding mills in a manner that is often overly complex, neglects economics, and is not clearly focused on the end user’s goals. This paper surveys current industry practices, and proposes an improved approach to standards writing recognizing that product design, procurement, manufacturing, and quality are all inter-related in contributing to a project’s success. The lessons learned here can be extended to specifications for all types of machinery.

Jan 1, 2012

By J. Paraszczak

ABSTRACT: Application of teleoperated and automated (or “autonomous”) mobile equipment in under-ground metal mines represents a promising avenue for overcoming some of the challenges facing the industry. This paper addresses the overall effectiveness of autonomous loading and haulage equipment compared with conventional human-operated machines. Factors affecting availability, utilization, and production rate are explored, and an emphasis is placed on some problems and risks not present in conventional human-operated systems, as well as on the character and criticality of autonomous equipment. The need for a more in-depth analysis of factors affecting overall autonomous equipment effectiveness is stressed; these factors should be taken into consideration at the stage of feasibility studies. The paper concludes with recommendations and directions for future research.

Jan 1, 2010

By R. D. MacEchern, M. C. Rockwell

"This paper describes the research and tests carried out to recover the readily available barite from the tailings produced by the Nystone Chemical Ltd. operation at Debert, N.S. The tailings comprised 70-80% of the original feed and contained about 20-25% Baso4 .The objective of the research, undertaken during 1982, was to produce a barite concentrate which would meet the American Petroleum Institute (API) barite requirements for use in drilling mud. Samples from the tailings pond were examined and analysed to determine the tailings characteristics.Preliminary test work was performed on the tailings samples using a Haultain Superpanner, Wilfley tables and Humphrey's spirals. The grade of the barite concentrate retrieved did not satisfy the API barite requirements.The fineness of the tailings and the fact that approximately 80% of the barite was contained in the -200 mesh (0.074 mm) size fractions, indicated that flotation of barite from the tailings might be successful."

Jan 1, 1984

By Lorna Ortiz-Soto

A series of titiania- and silica-supported Au, Pt and Pt-Au catalysts prepared through different synthetic routes have been investigated in terms of their structural properties, adsorption of CO, and catalytic activity for the selective catalytic reduction of NO by propylene and the oxidation of and CO. Catalysts prepared by incipient wetness impregnation from individual Pt and Au precursors, exhibited characteristics very similar to those of monometallic Pt catalysts. This behavior is consistent with a model in which the two metals remain segregated due to their miscibility gap, and only Pt participates in the adsorption of CO and the reactions under consideration. In contrast, catalysts prepared from a Pt2Au4(C=CtBu)8 organo-bimetallic cluster precursor exhibited different behavior both in terms of CO adsorption and their catalytic activity for the three reactions examined. The combination of the kinetic, spectroscopic and structural characterization data suggests that in this case Pt and Au remain intimately mixed in the form of Pt-Au bimetallic particles, and that the presence of Au modifies the behavior of Pt.

Oct 1, 2003

By Michael Samis

NOFLEX valuation results ? CF deviations and net CF risk discount factors ??Cash flow deviations indicate average cash flow variability. ??Net cash flow riskdiscount factors (NCFRDFs) indicate the size of the risk adjustment applied to a cash flow. NCFRDFs profile should change with variations in cash flow uncertainty since the risk adjustments applied to the project cash flow reflect investor sensitivity to uncertainty.?DCF and RO will often produce different NCFRDFs for the same project since they use different methods of risk-adjustment.

May 1, 2006

By Christopher H. Clement

The International Commission on Radiological Protection (ICRP) is an independent, international organization that advances for the public benefit the science of radiological protection, in particular by providing recommendations and guidance on all aspects of protection against ionizing radiation. This presentation touches on aspects of The 2007 Recommendations of the ICRP, a fundamental document that lays out the system of radiological protection for all exposure situations and types, and focuses on other recent publications relevant to the uranium industry. Of particular relevance are the 2009 ICRP Statement on Radon and the accompanying report on lung cancer risk from radon.

Aug 1, 2010

By T. I. Kunkel

The economic prosperity of many Canadian communities depends on resource extraction within the traditional territories of Indigenous people. The geographic sites where these resources are situated are also areas where these Indigenous people have sustained themselves for millennia through hunting, fishing, trapping, and gathering activities. These traditional activities provide not only sustenance, but also cultural and spiritual values, and the ability to transmit oral Indigenous cultures and customs from generation to generation. The multimillion dollar revenue mine project proposed within the Cariboo Chilcotin region of British Columbia is situated geographically in a location which has sustained the Tsilhqot?in people for millennia. However, this group of people have important social and cultural values nested within the traditional activities at this location. These values are typically not at the forefront of resource development. Using Indigenous research and grounded theory, this research paper briefly outlines Aboriginal values of the First Nations communities within the Cariboo Chilcotin region and some lessons learned from the Tsilhqot?in people during the environmental assessment of the mine proposal.

Aug 1, 2013

By M. R. P. Snow

"This paper outlines geotechnical conditions that commonly exist in underground, hardrock mines and the challenges posed for ground-support steel, specifically rockbolts, used in these environments. A model is proposed whereby the in-situ stress and rock-mass classifications (based on Bieniawski’s rock mass rating) form the basis of determining the desired steel properties of the rockbolts used. Based on the ASTM F432 bolting specification, recommended minimum steel properties are defined for three ranges of in-situ stress levels, each with their own six ranges of RMR values. Heat treatment for the steel can be specified once these minimum steel properties are known.RÉSUMÉ Le présent article décrit les conditions géotechniques qui existent fréquemment dans les mines souterraines de roches dures et les défis que cela pose pour le soutien de terrain en acier, plus spécifiquement les boulons d’ancrage utilisés dans ces environnements. Un modèle est proposé dans lequel les contraintes in situ et les classifications de la masse rocheuse (selon la classification de la masse rocheuse de Bieniawski) servent de base pour la détermination des propriétés désirées pour l’acier des boulons d’ancrage utilisés. En se basant sur les spécifications de boulonnage de l’ASTM F432, les propriétés minimales recommandées pour l’acier sont définies pour trois plages de niveaux de contraintes in situ, chacune avec sa propre plage de six valeurs de classification de la masse rocheuse (RMR). Un traitement thermique pour l’acier peut être spécifié une fois que ces propriétés minimales pour l’acier sont connues."

Jan 1, 2016

RISKGATE is an interactive online risk management system developed by the Minerals Industry Safety and Health Centre (MISHC; University of Queensland) to assist the mining industry in implementing continual improvement in management of major unwanted events, and so maximising health and safety performance. A comprehensive body of knowledge has been compiled from diverse mining industry experts for risk management of tyres, collisions, fires, isolation, strata underground, ground control open cut, explosions, explosives, manual tasks and slips/trips/falls. This paper presents an overview of the body of knowledge captured from diverse mining industry experts for the management of unwanted strata incidents, and explosions in the underground environment. This knowledge is divided into a series of initiating events within both topics (as listed) with further degrees of classification based on design, operation, and management concerns. Strata Underground Initiating Events: Explosions Initiating Events Loss of strata control at longwall face Fire or ignition in a sealed area Loss of strata control in outbye roadways Fire or ignition in an unsealed goaf area Loss of strata control in roadways under development Fire or ignition in an extraction face Loss of control of overburden and caving behavior Fire or ignition in outbye Loss of pillar system stability Loss of control of goaf edge in pillar extraction Fire or ignition in a development panel or first working Loss of strata control in shafts The system guides the user in generating substantive and leading edge controls to assist industry stakeholders in the design, management and reporting of organisational and regulatory compliance requirements. From a broader industry perspective, RISKGATE provides an environment for knowledge capture and knowledge exchange to drive innovation and best practice in the identification, assessment and management of risk. By capturing operational knowledge from industry experts, RISKGATE provides a cumulative corporate memory at a time of high personnel turnover in the coal industry.

Aug 1, 2013

By Réal Marcotte

L'industrie minière représente un apport économique important pour le Québec ; cette production est très diversifiée et répartie dans plusieurs régions. Hormis les forges du St- Maurice au XVIIe siècle, l'industrie minière québécoise commence en 1862 dans la Beauce avec l'exploitation de placers aurifères dans les affluents de la rivière Chaudière; à la même époque, on met en production les mines de cuivre Eustis, Albert et Capelton, près de Sherbrooke1; à partir de 1881, les mines d'amiante et de chromite au voisinage d'Asbestos et de Thetford commencent à voir le jour. Dans les années ?20, l'extraction de métaux précieux et usuels débute en Abitibi- Témiscamingue; durant les années '50, le fer et l'ilménite de la Côte Nord, ainsi que le cuivre de Murdochville et Chibougamau, commencèrent à être mis en valeur. Plus récemment, soit durant les années '80, le sel des Iles-de-la-Madeleine et le graphite des Hautes Laurentides s'ajoutèrent aux produits que nous commercialisons. Finalement, soit en 1998, le Québec devenait un important producteur de nickel avec le démarrage de la mine Raglan, au Nunavik. L'exploitation d'une mine peut nécessiter l'extraction de grandes quantités de roches stériles, particulièrement lorsque la production se fait à partir d'une fosse à ciel ouvert. De plus, étant donné que les minéraux et les métaux mis en marché ne constituent qu'une fraction du minerai extrait, il faut le concentrer : on se retrouve alors avec des proportions plus ou moins importantes de résidus finement broyés. Ces deux types de rejets totalisent bon an mal an environ 100 millions de tonnes. Lorsque cela est possible, ceux-ci sont, soit valorisés comme matériaux de construction ou retournés dans leur lieu d'origine afin de soutenir les murs des excavations. Toutefois, une bonne partie est accumulée en surface dans des aires aménagées spécifiquement à cette fin ; comme le montre la figure 1, la superficie utilisée à cette fin a progressé parallèlement aux booms miniers que nous venons de mentionner pour atteindre actuellement environ 15,600 hectares, dont environ la moitié sont situés sur des aires encore en activité.

Nov 1, 2002