Search Documents

By G. Viramontes-Gamboa

Approximately 70% of world copper reserves consist of the mineral chalcopyrite, and much international effort has focused on its study. Ultimate objectives include the development of environmentally friendly alternatives to smelting, and technologies to treat low-grade ores, for which concentration and smelting are economically unviable. Unfortunately, chalcopyrite leaching is inefficient in H2S04-Fe2(S04)3-FeS04 solutions, which is considered to be the most desirable oxidizing medium for leaching of copper sulfides, since the chemistry is well known, corrosion of industrial equipment is negligible, subsequent copper recovery by SXlEW is well established, and environmental impact is minimal. The main reason for this inefficiency is the self-passivation of chalcopyrite. We have devoted considerable effort in the understanding of this phenomenon, and have developed a predictive electrochemical methodology capable of establishing a priori the precise range of potentials within which chalcopyrite leaches and where it is passivated. Since potential control is a critical parameter in chalcopyrite leaching, this experimental methodology can be very useful for establishing the best conditions to leach chalcopyrite. In this paper, the scientific foundations of this predictive experimental technique are presented, and its practical application is demonstrated by comparing its predictions with leaching experiments from the literature.

Jan 1, 2007

By J. F. Shirley

"Very seldom, if ever, is a molybdenite by-product plant operated exactly the way the process design engineer visualizes it. The best thing the design engineer can do is provide a sound, basic circuit with enough room and flexibility in order that the operating staff can make the necessary modi fi cations to optimize the process. The plant, with minor modifications, should be capable of handling more than one process. This is especially true when the client is having the plant designed for a new process.The writer would like to propose the following ten ""rules-of thumb"" for designing by-product molybdenite plants where the molybdenite is floated out of a copper concentrate. The term rules-of-thumb is used, because there are probably valid reasons for not using one or more of them in a particular plant design. In fact it was 1980 before the writer was all owed to start up a plant where all of these rules were honored in the plant design. This was after 19 years of experience in the design of molybdenite by-product processes and plants. The main reasons for not following the rules are available capital, available space, and the client's experiences based on pilot plant and laboratory test results."

Jan 1, 1981

By D. R. Winchester

"I wish to thank you and your organizers for inviting me to address you at this point in time when we are all concerned for the future of the mineral industry in Canada.My topic ""Some Initiatives of Government Assistance to Industry Applicable to Mineral Processing"" is purposely limited in scope. To cover the entire range of initiatives in detail would take me all day, and at best, would be a mere recital of program titles, and a one sentence summary of the contents of the program. As you know, OREE or Regional Economic Expansion, is in the process of being amalgamated with elements of the Department of Industry, Trade and Commerce. We will become Regional Industrial Expansion or ORIE. If the name Canada Dry becomes popular, I don't think we will object as we hope to become a good mixer. The entire departmental thrust has been re-evaluated, and is in the process of being re-constituted to better serve the nation, and industry as a whole. Amalgamation of the industrial, trade promotion and marketing support skills of IT&C, with the regional development orientation and decentralization program delivery mechanisms of DREE, will, it is believed, provide better support to industry on a national and regional basis."

Jan 1, 1983

By P. Woo, N. Brodusch, R. Gauvin, H. Demers

The scanning electron microscope (SEM) was primary developed for imaging applications. With the introduction of the Si(Li) energy dispersive spectrometer (EDS), simultaneous imaging and x-ray microanalysis became possible. However, long working distance and high current were needed because the position and small solid angle of the EDS detector. The high spatial resolution is generally obtained at short working distance with a SEM. Unfortunately x-ray microanalysis is never performed in the best imaging conditions. The annular silicon drift detector system is inserted below the objective lens which gives a higher solid angle (up to 1.3 sr). In consequence, a lower working distance and probe current can be used. An improved spatial resolution becomes possible during x-ray microanalysis. With this x-ray detector installed on a cold-field emission scanning electron microscope, quantitative x-ray microanalysis with high spatial resolution at low beam energy and low current becomes possible with the possibility of using the various different type of imaging at the same time. Also, since the count rate can be as high as 1,500 kcps, which lowers significantly the detection limit of elements as well as the minimum feature sizes of different phases that can be distinguished.

Jan 1, 2014

By V. Itkin

"Three methods were tested for the beneficiation of aluminum scrap, generated by heavy medium separation of non-ferrous automobile scrap residue. These were: crushing in a shredder followed by screening; grinding in a ball miff followed by screening; and eddy current separation. The best results were obtained with the grinding-screening method. IntroductionThe usual method of aluminum alloy reclamation from non-ferrous automobile scrap residue consists of a two-step heavy medium separation to remove materials lighter than and heavier than aluminum. The resulting aluminum scrap still contains over 15% impurities such as stones and glass, heavy rubber, insulated copper wire , plastics and heavy metals entrapped by macerated aluminum piece s, composite fragments, etc.(2). Upon melting, these impurities create difficulties and yield a low ingot recovery-65% to 70%, hence small foundries avoid this material.There are a number of ways to improve the quality of aluminum scrap such as:(1 ) crushing of the scrap, which powders the brittle content , a major impurity component, followed by screening out of the dust(2) eddy current separation , which removes metals from the material flow, and(3) implement better methods for density separation.The eddy current separation and two variants of the comminution-screening technique were studied by Intermetco Ltd., Hamilton , Ontario."

Jan 1, 1986

By W. J. Adams

It is recognized that within life cycle assessment that the eco-toxicity potentials (TPs) derived for metals require additional research to improve their reliability. Current models used to develop TPs do not include important fate process for metals such as speciation and bioavailability. Toxicity potentials are standard values used in LCA to enable a comparison of potential toxic impacts between substances. Huijbrechts (2001) calculated toxicity potentials for 181 substances utilizing the USES model for six impact categories, i.e. freshwater aquatic ecotoxicity, marine aquatic ecotoxicity, freshwater sediment ecotoxicity, marine sediment ecotoxicity, terrestrial ecotoxicity and human toxicity (not considered here). Marine ecotox potential for metals is typically high using this approach, whereas most open ocean metal concentrations are very low. A sensitivity analysis of the USES-LCA model was undertaken using copper as an example. Results indicate: fate processes on the global scale are driving the marine water and sediment TPs for copper most; the second most important fate parameter is sedimentation from the water and burial in deep sediment layers; inclusion of speciation and bio-availability processes would be very beneficial; more accurate estimates of input parameters should be used, and the PNECwater and PNECsediment and all partition coefficients for metals should be updated in the model.

Jan 1, 2007

By N. Djilali

Many of the transport phenomena encountered in proton exchange membrane fuel cells occur intrinsically at the microscale level. Physically representative models that fully account for the salient physico-chemical and transport processes in PEM fuel cells are necessary to achieve truly predictive models that can be used with confidence to: (i) gain a better understanding of in-situ processes and couplings, (ii) explore new concepts, and (iii) support design and optimization. The development of more general, rationally based macroscale models requires use of knowledge on the microscale level to provide guidance, and to determine the required parameters and coefficients (model "constants"). In this paper we present a new membrane transport model, the binary friction membrane model (BFM2), recently developed to account for coupled protonic and water transport in polymer membranes. This general model is based on rational and physical consideration, removes several of the limitations of the empirical models used to date, and is formulated for all purfluoro-sulfonic acid membranes. The use of the BFM2 in a fuel cell model is illustrated highlighting significant performance predictions compared to existing empirical model. The second part of the paper addresses the fundamentals of two-phase transport in hydrophobic gad diffusion media. Computational and experimental visualizations resolving the microscale dynamics of water transport between the fibres of a GDL are presented, revealing transport mechanisms that are, contrary to assumptions used to date, dominated by fingering and channeling.

Jan 1, 2005

By S. B. Mishra

Ni-20Cr metallic coating was deposited on a Ni-based Superalloy (3Fe-19.5Cr¬0.3Ti-Balance Ni) by a shrouded plasma spray process; NiCrA1Y was used as a bond coat. Erosion studies were conducted on uncoated and plasma-spray coated superalloy specimens using an air-jet erosion test rig at a velocity of 40 m/s and impingement angles of 30° and 90°. The coating has been characterized for porosity, microhardness and microstructure and X-Ray Diffraction (XRD). An electron probe micro analyzer (EPMA) was used to obtain X-ray elemental mappings of the coating along the cross-section. Scanning electron microscope (SEM) with EDAX attachment was used to analyze the eroded surfaces.

Jan 1, 2005

Presentation Outline Introduction Deposit Characteristics Geology Grade, Value and Tonnage Estimates 2006 Advanced Program Drilling Bulk Sampling DMS Test Facility 2006 Exploration Summary

May 1, 2006

By Bryn Harris

Answer to the question is given as 42! Asked the wrong question So got the wrong answer How does this apply to the mining industry? And particularly to this session on Water? Water is just one aspect of mining/minerals/metals Should not be looked at in isolation Need to adopt a ?holistic? approach

May 1, 2013

By M. Bozorgtabar

Metal Matrix Composites (MMC) have a ductile matrix containing ceramic particles, Due to their improved wear properties, Al?SiC composites have economical applications in many industrial uses where wear is a problem, One of the most serious difficulties in manufacturing Al-SiC composites is obtaining adequate 'wetting' of the particles by the melt. In this research work, a stir casting system was designed for the improved manufacturing Al-SiC composites, The effect of some production variables such as the addition of SiC particles to the aluminum melt on wettability, was also studied. The results showed that the manual addition of particles would not be successful in manufacturing and that a system of adding silicon carbide particles through controlled temperature, atmosphere and improved mixing was needed.

Jan 1, 2005

By B. Panton, J. Carvalho, E. T. Brown

"A major consideration in the design of high capacity tiedown anchors for dam, bridge and tower foundations is the tensile resistance of the rock mass to pullout, typically as a result of overturning moments or hydrostatic uplift. Rock mass pullout capacity for installed anchors is developed from the tensile strength and fracture propagation properties of intact rock, the orientation and physical properties of the discontinuities and anchor confinement at depth. The typically assumed, but generally conservative, design approach is to calculate anchor pullout capacity using the dead weight of a uniformly shaped inverted “cone” with an assumed initiation point and breakout angle. In some cases, some tensile or shear strength is considered across the area of the assumed pullout cone, however, these strength estimates are based primarily on based on limited historic testing data, empirical relationships for rock mass strength developed for other applications, and engineering judgement.As an alternative to the current foundation anchor design method, this paper presents a new approach to the rock cone pullout problem using Discrete Fracture Networks (DFN) combined with numerical simulations. The simulations presented in the paper investigate the influence of fractures in a synthetic rock mass on ultimate anchor strength. In addition, the global influence on fracture network statistics on rock mass pullout failure is also discussed and it is contended that some of the aleatory and epistemic uncertainty inherent in the design of rock anchors can be reduced by considering fracture statistics in anchor design."

Jan 1, 2015

By D. Seo, P. Au, S. Yandt, N. Tsuno, A. Sato

Nickel-base single-crystal superalloys are used for gas turbine airfoil applications due to their excellent high temperature properties. A good understanding of the mechanical response of these alloys under different temperature and loading conditions is essential for modeling their behavior. In this study, the low cycle fatigue behavior of CMSX 2 oriented with the loading axis along [001] was investigated under zero-compression strain-controlled loading at 1100°C. The experiments were performed with or without a two-minute dwell (hold) in compression. The microstructure before and after testing was analyzed to understand the deformation characteristics including the effect of dwell.

Jan 1, 2010

By A. Allaire

The Goldex operation of Agnico-Eagle Mines (AEM) commenced operations in the spring of 2008. Following some months of initial operation, the grinding circuit capacity was under-performing according to the original design throughput. BBA Inc. (BBA) was commissioned, in February 2009, to study the different options and recommend the quickest and most cost-effective solution to increase the grinding circuit throughput rate. The mandate was to increase the throughput of the grinding circuit to beyond the original design of 7,000 tpd to 8,000 tpd or greater, while retaining the existing SAG and ball mills. The circuit was modelled using JKSimMet software to evaluate the different options, each with a number of different operating parameters. The option of secondary crushing of the SAG mill feed was retained. Comparison of the different options and simulation outcomes, design of the secondary crushing circuit, operating conditions, and initial adjustments in the design and operating results of the new grinding circuit are discussed in this paper.

Jan 1, 2012

By Ian Thomson

OBJECTIVES OF EXPLORATION ? Prove/Disprove presence of potentially economic mineralization ? Keep on budget ? Minimize negative environmental impacts ? Gain a ?Social License to Operate? (SLO) WHAT IS A ?SLO? ? Granted by the local community ? Intangible, informal, non-permanent ? Has to be earned and then maintained ? Defined as ? Ongoing Approval (BSR and AccountAbility) ? Ongoing Approval, broad social Acceptance (Joyce and Thomson) ? Ongoing Acceptance (Nelson, and many others) ?Expression of the quality of a ?relationship?

May 1, 2010

By H. C. Cooke

"The Part of the Eastern Townships dealt with in this paper is shown in the accompanying figure. Each rectangle represents one of the topographic maps published by the Department of National Defence on a scale of one mile to one inch. Each sheet covers an area approximately 24 miles long and 17 miles wide, or slightly more than 400 square miles. The north-western part of the area figured, comprising the Upton, Aston, Becancour, and the two unnamed sheets, (Three Rivers and Yamaska), together with most of the Lyster, Drummondville, and St. Hyacinthe sheets, is largely covered by clays and sands deposited in interglacial and post-glacial time in the Champlain estuary, so that outcrops are widely scattered and in-formation is correspondingly sketchy. In the remainder of the area figured, comprising more than 4,000 square miles, outcrops are reasonably numerous and have been mapped on a scale of one mile to one inch, and the structure is moderately well understood.The Eastern Townships was an area of intense orogenic disturbance, apparently beginning late in the Cambrian or early in the Ordovician, and continuing till well on in the Devonian period. During this long period, which may have lasted for a hundred million years or more, the area was subjected from time to time to intense thrusts from the east and southeast. Each of these caused folding of the rocks, accompanied by faulting, raised parts of the area above sea-level, and presumably created ranges of mountains. Long periods of erosion cut away the mountains and reduced the area nearly to sea-level after which subsidence carried it below sea-level, and permitted further sediments to accumulate before the next thrust initiated the next cycle.The first of these movements, as stated, appears to have been in late Cambrian or early Ordovician time. The group of rocks known as Caldwell was folded and, south and east of the town of Asbestos, was thrown into great drag-folds before deposition of the next overlying series, termed the Beauceville, began. Unfortunately, the date of this orogeny is very imperfectly known, because both series of rocks have been so crushed and sheared that almost all fossil remains have been destroyed. Graptolites, found in one place in slates generally considered Beauceville, give that series a tentative Middle Ordovician age. In the Caldwell rocks, which underlie the Beauceville with great unconformity, no fossils whatever have yet been found. Thus, if the Beauceville rocks are correctly dated as mid-Ordovician, the best that can be said of the movement folding the Caldwell is that it took place at some time before Middle Ordovician."

Jan 1, 1949

By Peter McGoldrick

This Talk ?Australian deposits in world context ?Geological setting: the importance of the basin fill ?Key deposit features using HYC (McArthur River) and Century as examples ?The difference between Aussies & Canuuks(that is between Australian & Canadian sedexdeposits!) ?Timing of mineralization ?Sources for metals and ore fluids ?What makes a super giant sedexdeposit?

May 1, 2006

By J. G. Ross

A DESCRIPTION of the block-caving system of mining as practised at the King mine of Asbestos Corporation, Limited, Thetford Mines, Que., was presented. at the Annual Meeting of the Institute held in Quebec city, in April, 1934. The paper was published in the Transactions of the Institute for 1934. There has now been recovered, by this method, one million tons of ore, and a review of experience indicates that the method was well planned and has been executed smoothly. In approaching the problem of selecting the type of mining best adapted to this deposit, the method had to be one which would be low in cost, use no wood, and not disturb the surface immediately bounding the ore-body on two sides. Prior to 1931, block-caving had been considered but rejected, as it en-tailed disturbance of the surface area which lay within a 45° angle of the lowest contemplated workings, if the practice of such mines as Ray, Miami, Inspiration, and Morency, where this type of mining has been used extensively, was followed. At these properties there have been mined large tannages at outstanding low costs, but an extensive surface area has been disturbed in each case. In some instances, townsites in the mining area have had to be abandoned, and dwellings, not considered worth moving, have been allowed to fall into the depression. A study was made of the principles involved in the various types of block-caving, the existing information on ground movement, subsidence, etc., also being carefully analysed. Toward the end of 1931, a plan was conceived whereby the country adjoining ground being caved might be held permanently in place and undisturbed. The success of such a scheme was essential to the application of block-caving at the King mine on account of property boundaries, the Quebec Central Railway right-of-way, and expense of moving buildings. Study of existing data on caving and movement of rock, caused by sub-surface excavations of sufficient unsupported area to result in failure of the backs, indicated, in practically every instance, that such movements followed certain definite laws of mechanics.

Jan 1, 1936

By Chris McBean

Due diligence mistakes ? lost opportunity ? High profile write-downs and cost overruns ? Result ? tight market for financing ? Implications for due diligence ? need to get it right ? maybe only one chance ? Where should focus be?

May 1, 2013

By José J. Suárez

Abstract: Globally, the mining industry is expected to face the following challenges through 2020: 1. Sustaining growth amidst fierce competition 2. Containing cost increases and managing through the cycle 3. Attracting and retaining talent 4. Managing environmental concerns and improving sustainability 5. Managing volatility risks in commodity markets Our experience and research reveals that the higher performing global miners are adopting many of the following strategies: (1) Adopt a Global, Agile Operating Model (2) Be the Developer of Choice (3) Drive Capital Efficiency (4) Be the Employer of Choice (5) Integrate the End-to-End Business Model (6) Move to the Virtual Mining Value Chain This paper/presentation will provide data obtained through research on five (5) challenges facing the mining industry, and on the six (6) strategies that high performing global miners are adopting.

May 1, 2013