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By R. A. McIvor, R. S. Rafuse

"INCO Limited purchased a custom designed mobile hoist rope winder/tensioner in 1988 from TimberLand Equipment Limited to handle Large hoist ropes and serve as an emergency hoist. This paper describes the operation of the winder/tensioner and some of the different applications that the machine has been used to handle large loads.IntroductionINCO Limited operates 24 mine hoists in the Ontario Division and has approximately 50 miles of mine hoist rope hanging in the shaft plus an equal amount on spare reels. The mine hoist ropes range in size from )( inch to 2.305 inches in diameter with the majority being 1 3/4 inches and above. Prior to the procurement of a new high powered winder/tensioner in 1988, the mine hoist ropes were handled with a variety of methods and equipment using hydraulic or pneumatic powered reel winders. The largest such reel winder has a pull rating of 8000 Ibs and travels approximately 40 ft/min. Head ropes for the tower mounted friction hoists were installed and removed using a magazine on the hoist drum to wind and unwind the rope because the loads were greater than the capacity of the existing machinery. It was recognized that a large high capacity machine would improve the productivity for handling the larger hoist ropes and a feasibility study was undertaken to determine the parameters for such a machine."

Jan 1, 1995

By Yves Pépin, Sylvain Lefebvre, Dimitrios Filippou, Guillaume Hudon

"Titanium dioxide pigment plants using the so-called “chloride process” produce considerable amounts of chloride waste, which contains predominantly iron chloride. In most cases, this waste is dissolved in a weak hydrochloric acid solution and then neutralised. The metal content of the waste is dumped as hydroxide sludge, while its chloride content is lost in an effluent.Rio Tinto Iron & Titanium has developed a new proprietary process whereby pure metallic iron and chlorine gas are recovered from chloride waste by electrolysis. This process uses a two compartment cell separated by an anion exchange membrane to prevent iron cycling between its trivalent and divalent valence. The cathode is made of titanium Grade 7, while the anode is a dimensionally stable one of the type “metal–mixed metal oxide” (MMO) for the evolution of chlorine gas. The catholyte is concentrated and pH-adjusted iron-rich chloride solution originating from chloride waste. The anolyte is recirculating solution containing alkali or alkali earth chlorides such as MgCl2, NaCl, etc. Current efficiencies above 90% can be achieved at temperatures about 80°C using catholyte solutions almost saturated in iron chloride and other chlorides.In this paper, we discuss the details of this process, and how this could be integrated within a chloride pigment plant for the treatment of chloride wastes."

Jan 1, 2016

By M. Sokoto, H. Hata, K. Nishina, K. Haiki

Fluoride ions in zinc electrolyte cause corrosion to aluminum cathode plates at zinc electrowinning process, so we have developed an iron compound as a fluoride ion adsorbent used in zinc sulfate solution. The iron compound is synthesized from FeC13 solution with a small amount of sulfate ion by neutralizing reaction with Na2CO3 solution. The fluoride ions adsorbed on the surface of the iron compound are desorbed in alkaline solution and the iron compound can be reuse as a fluoride ion adsorbent. Moreover, if adsorption capacity of the iron compound decreases, it can be dissolved in HCl solution and re-synthesized.

Jan 1, 2008

By F. Rosenblum, P. Spira

"Self-heating of broken sulphide ore or waste rock underground can lead to ignition and cause serious problems in a mine operation. An extensive study has demonstrated that it is caused by oxidation of certain species of pyrrhotite. Self-heating was found to take place in two stages, first progressing from ambient temperature to 1000C with exothermic formation of elemental sulphur in the presence of moisture and oxygen, and proceeding to a second stage in which the sulphur oxidizes to SO2. Ignition may eventually follow. An apparatus was developed to assess the propensity of sulphide rock to self-heating and the potential for hazardous behaviour. The effect of temperature, time, rock size, and surface treatment with chemicals is presented. On the basis of these results, possible approaches for preventing a runaway reaction are suggested for further investigation.IntroductionThe oxidation of sulphide ore, waste rock or tailings backfill, which may cause hazardous conditions underground through heating, oxygen depletion and, in some cases, fire, is well documented (Farnsworth, 1977; Ninteman, 1978; Rosenblum et al., 1982; Reimers, 1987). The self-heating mechanism, nevertheless, has not been satisfactorily explained. The onset of heating from ambient temperature, in particular, has not drawn the attention of researchers. In the course of a previous study (Rosenblum et al., 1982) aimed at finding a method to assess the hazard from using sulphide tailings as backfill, the authors developed an apparatus to measure self-heating rate under controlled, near ambient conditions. This has since provided decisive information in backfill investigations in the Noranda Group.The test methodology devised for tailings failed to predict self-heating in a broken waste rock known to be active. Upon repeated testing, however, a freshly crushed sample began to exhibit appreciable heating and oxygen uptake (Fig. I). After 14 tests, the self-heating rate reached a plateau of about 4O°C/h and then fell progressively to < 5°C/h after 30 tests. It was hypothesized that weathering in the presence of moisture and oxygen during testing had caused the onset of self-heating. Active tailings, on the other hand, are exposed to natural surface oxidation and need not be weathered to show heating. Based on this finding, a new apparatus was developed capable of simultaneously weathering a sample of rock and monitoring its self-heating behaviour."

Jan 1, 1995

By K. Chotruangprasert

This paper explores Global Reporting Initiative (GRI) reporting practices within the mining industry. Specifically, this paper investigates how and why a mining company makes voluntary reporting decisions to include the GRI indicators that may be considered ?negative? to the company?s reputation. Due to the voluntary nature of the GRI Guidelines, a GRI adopter is not legally obligated to report every GRI indicator. Not surprisingly, empirical studies that evaluated the extent to which companies? sustainability reports meet the GRI requirements (Guenther, Hoppe, & Poser, 2006; Morhardt, Baird, & Freeman, 2002; Samy, Odemilin, & Bampton, 2010; Skouloudis, Evangelinos, & Kourmousis, 2009) have found that reporting practices of the companies under their studies are well below the standards reflected in the GRI Guidelines. An influential study by Clarkson et al (2008) uses economic-based and socio-political theories to explain variation in companies? environmental disclosure. They have found that, as predicted by economic-based theory, superior environmental performers disclosed more ?hard? (i.e. verifiable) environmental information. Inferior environmental performers are found to disclose more ?soft? (i.e., not easily verifiable) claims, which is consistent with socio-political theories (Clarkson, Li, Richardson, & Vasvari, 2008). However, this study and the existing literature do not adequately explain why a company may act in a way that cannot be explained by economic-based and socio-political theories, for example, why it would report some negative soft data that it is not required to report. This paper intends to address this literature gap. GRI reporting by a Canadian mining company, which I would like to call ?Company C?, is used as a case study for this paper. Company C was selected for this research because in addition to ?positive? information, its GRI-based sustainability report also includes both hard and soft ?negative? information such as grievances. Research methods include interviewing Company C?s employees who are involved in preparing GRI reports and reviewing documents prepared both by the company and by external parties. I find that integrative social contracts theory (ISCT) offers a valuable explanation to Company C?s reporting practices. From the ISCT perspective, Company C?s management appears to feel that the company is obligated under social contracts to be transparent. Therefore, Company C disclosed both positive and negative social and environmental information to the public because the management appeared to think that it is the right thing to do. At the same time, being transparent about the bad news gave the company an opportunity to conclude that it had done something to avoid future occurrence of the negative incidents. Therefore, I propose that, in addition to the economic and socio-political theories that are more often used in literature, insights from ISCT are instrumental in improving our understanding of the corporate non-financial reporting practices phenomenon.

Aug 1, 2013

By John Emery, George Wang

Research and applied utilization activities for the increased use of ferrous and nonferrous slags in construction are presented. The overall use of blast furnace slag is relatively well known for a range of construction applications from aggregates to slag cements. In contrast to blast furnace slag, which is volumetrically stable and straightforward in its construction uses, steel slag contains hydratable oxides that can result in volumetric instability that must be dealt with through appropriate steel slag aging, testing and quality control to ensure its appropriate use. Particular care must be taken to prevent potential steel slag expansive behaviour in confined applications. Quality requirements and guidelines on steel slag expansivity to further the use of steel slags, with demonstrated acceptable performance, are outlined. There is a full range of proven construction uses - from aggregate to cementitious materials - for copper, nickel and phosphorus nonferrous slag. The use of air-cooled nickel slag is presented, based mainly on practical highway construction experience. It has been shown that air-cooled, crushed nickel slag can be an excellent aggregate in granular base, engineered fill and hot-mix asphalt. There is a good potential for increased ground, granulated copper and nickel slags use as supplementary cementitious materials that is being developed, which takes advantage of the &apos;latent energy&apos; content. The scope of a new technical text in preparation on the technology of slag utilization is reflected throughout to provide a practical context for the engineer.

Jan 1, 2004

By C. Pichler, J. Antrekowitsch

During the production process of steel and other metals a lot of different by products are generated in high amounts. Some of these residues are recycled to recover valuable metals like zinc, lead, copper and others. Especially the treatment of steel mill dust presents a great challenge. The need for new technologies can be seen in the wide range of available recycling concepts for steel mill dust treatment, however most of them have significant disadvantages. An example is the waelz process, which generates about 650 to 700 kg slag during the treatment of 1000 kg steel mill dust. This so called "waelz slag" must be dumped in the most cases. To avoid a landfilling all generated products must be able to get reused in another application. A so called "Zero Waste Process" can be reached with the "2SDR Process" (Two Step Dust Recycling Process), in which the dust is treated on an liquid iron bath generating cast iron, inert slag and zinc oxide. These products have a further usage and can also be sold. The paper focuses on the process development through trials in lab and technical scale up to planned pilot scales, with an accompanying characterisation of the generated products were done.

Jan 1, 2014

By F. Parada

During copper smelting and converting processes, slag generated is pyrometallurgically cleaned and then disposed, containing around 1 % of this metal. However, important amount of molybdenum initially contained in concentrates also goes to the slag phase. Research on molybdenum recovery from water granulated slags using acid leaching at low temperatures was conducted to find an efficient way for molybdenum extraction with lower magnetite in the slag. However because of the high fayalite content high acid consumption was found. Molybdenum can be recovered from solution using ionic exchange resins, but high silica content interferes with extraction. Some studies addressed to minimize silica extraction as well as alternatives of selective silica precipitation in order to develop a technically feasible process.

Jan 1, 2007

By J. A. Finch, M. Mimezami, M. S. Hashemi A.

The adsorption of magnesium and calcium ions on sphalerite and pyrite is discussed. These ions are common in process water and often considered be detrimental in sulphide flotation. The study attempts to characterize the adsorption mechanism, which has been less studied than the oxide system. Generally for oxides metal ion uptake occurs when cations are hydrolyzed. Our findings reveal that magnesium and calcium adsorb on sulphides at pH below hydrolysis, but adsorption is not chemical. At higher pH, charge reversal occurs that does correspond to presence of hydrolysis products. Advances

Jan 1, 2009

By Barton G. Stone

The mining and exploration industries have been using Geostatistics (Matheron, 1963) for the past forty years. It has been extensively incorporated into three dimensional block modeling software whose usage has reflected the growth in the use of personal computers since 1980. Because of the utility of geostatistical models in mining and production planning, much of the modern reserve and resource modeling is done by mining engineers, geostatisticians and geological engineers. Explorationists are initially less concerned with three dimensional models until such time as a deposit has been roughly delineated. However, the concept of regionalized variables in ore deposits deals with the effect of spatial correlations between data points in a three dimensional sample space and should be useful for optimizing the spacing of drill holes to allow maximum bang-for-the-buck in drilling programs. This paper examines three common deposit types (porphyry copper, VMS and intrusive gold) to examine whether geostatistical methods have been used to minimize drilling costs because of better understanding of spatial correlations. The three model types were chosen from publicly available corporate websites of Canadian based Junior Mining Companies. They include the Wolverine polymetallic zinc deposit of Yukon Zinc in Yukon, Canada; the El Morro Deposit in Chile (30 percent ownership by New Gold Mining Company, and the Fort Knox Gold deposit in Alaska and 50 percent ownership by Nova Gold Resources). Typically, individual mining corporations post their technical reports as CNI 43-101 reports on their corporate website as indications of the favorability or progress on their more exciting properties. Data considered for this paper was not collected or generated by the author, but the information was extracted from these publicly available sites and had a variety of authorship.

Oct 1, 2009

By Yuki Tsunazawa, Sho Fukui, Chiharu Tokoro

"A milling process is one of the important unit processes in mineral processing. In the milling process, the control of particle size distribution is necessary for the later physical separation process. Since the milling process is strongly affected by the equipment designs, operation conditions and raw materials, the control for particle size distribution of milling products is mainly based on empirical rules. Recently, the discrete element method (DEM) has been widely used as an effective tool to investigate the behavior of grinding media. Although the behavior of grinding media can be accurately simulated, it is not well-established the way to predict particle size distribution after milling by the DEM simulation.The objective of this study was to develop a new method to predict particle size distribution in ball milling using the DEM simulation. To predict particle size reduction, a correlation between experiments and the simulation was investigated in various operation conditions, that is, wide range of the rotation speed and the filling ratio of grinding media. In experiments, after lime stone was ground, the average and variance of particle size distribution were evaluated using some kinds of distribution equations. In the DEM simulation, direct simulation of particle disintegration in milling process is generally very difficult because of huge computational load. Therefore, collision energy between grinding media balls orgrinding media ball and wall was used as a factor of particle disintegration.As a result, a good correlation between experiments and simulation was obtained. In addition, the particle size distribution in ball milling could be predicted using this correlation. Therefore, these results indicated that the use of the correlation between experiments and the DEM simulation was an effective approach of predicting the particle size distribution in milling process."

Jan 1, 2016

By T. A. Apelt, B. J. Elliot

"In September 1993, the flash furnace at Kalgoorlie Nickel Smelter, KNS, was brought off line after almost 12 years of operation. This is a record campaign life for a flash furnace. The furnace was&apos; totally rebuilt and the capacity of the plant increased from 540 000 tpo to 750 000 tpa of concentrate throughput. The throughput increase was&apos; achieved through the construction of a 525 t/day oxygen plant and upgrading of various plant ancillaries. A number of significant design modifications were also built into the flash furnace and oxygen enrichment was implemented in the operation of the Peirce-Smith converters.This paper discusses the rebuilding of the flash furnace and design modifications made to furnace equipment and ancillary plant. Some preliminary post-startup operating data are presented.IntroductionIn September 1993, Campaign 6 of the flash furnace was concluded and the furnace brought off line for rebuilding. The campaign length was almost 12 years and set a new record for campaign length. Planning for the rebuild took place over the last five years of the campaign. A number of modifications to the design of the furnace and the ancillary plant were planned to coincide with the furnace rebuild. The furnace was rebuilt and recommissioned in 70 days. The increased plant capacity of 750000 tpa has been achieved by the construction of a 525 t/day oxygen plant and modifications made to ancillary plant which centred around increased p~ control, efficiency and hygiene. This paper examines the development and implementation of the modifications made to the furnace and ancillary plant. Preliminary post-shutdown performance data are presented."

Jan 1, 1995

By M. Phylli Bray

"Mining has the reputation of being a very ""macho"" industry. Recently, wider educational opportunities for women in nontraditional occupations and changes in mine technology have combined to make mining a viable career choice for women also. To benefit from this new resource, the mining industry faces the challenge of developing a different work environment from the one now burdened with sexism. Management supported initiatives are needed to facilitate such a transformation. The same rethinking of gender attitudes might also be extended to mining women in their traditional role as ""wife of"". The assumption that the male worker&apos;s wife is an unpaid adjunct is being questioned. It is suggested that women&apos;s separate concerns both as helpmate and as part of the mining workforce should be considered when planning for mining into the 21st century.IntroductionI must confess that, during the preparation of this paper, there have been many moments when I questioned my temerity. After all, I am not male, I am not an engineer, and I have never had a position in mine management. But as the wife of a mining engineer and a long-time resident of Northern Ontario mining towns, I do have an interest in the mining industry. This interest has had little to do with the technical and management aspects of the industry. Instead my research has been concerned with the impact the mining industry has on the people involved, particularly women, whether directly as employees or indirectly as wives. As I look toward the 21st century, I believe that the whole question of gender relations in the mining industry is one of the critical management issues smouldering below the surface."

Jan 1, 1995

By Neil Westoll

Extensive Global Network ?Working together, AECOM provides clients with a unique blend of global reach, local knowledge, innovation and technical excellence. ?43,000+ team members worldwide ?450+ offices ?100+ countries ?6 continents The Changing Climate ?Climate change is ?official??IPCC 2007 ?Climate change will create instability, change and opportunities ?Companies that are resilient and adapt will survive and evolve ?CO2/GHG emissions will be curbed by legislation ?How will this affect the mining industry? ?How can the mining industry adapt to the new realities?

May 1, 2009

By O. A. Ojo, O. A. Idowu, N. P. Wikstrom, M. C. Chaturvedi

Transient Liquid Phase Bonding (TLP) of a Nickel base superalloy, Inconel 738, was performed to study the influence of holding time, filler gap size, and temperature on the joint microstructure. Insufficient holding time for complete isothermal solidification of liquated insert caused formation of eutectic-type microconstituents along the joint centerline region. An increase in the eutectic thickness with increase in initial filler gap size was observed in joints prepared at a constant temperature and holding time. In agreement with prediction by conventional TLP diffusion models, an increase in bonding temperature for a constant gap size, resulted in decrease in the time, tf, required to form a eutectic-free joint by complete isothermal solidification. However, a significant deviation from these models was observed in specimens bonded at and above l 175°C. A reduction in isothermal solidification rate with increased temperature was observed in these specimens, such that a eutectic-free joint could not be achieved by holding for a time period that produced complete isothermal solidification at lower temperatures. Considerable enrichment of the liquated insert with base metal alloying elements at higher temperatures is suggested to be an important factor contributing to the observed departure from conventional TLP prediction.

Jan 1, 2006

By Gary Walters, Thomas Gonzales, David George, William Davenport, Andreas Siegmund, Suping Yao, Shijie Wang

The previous survey of world copper smelters was in 2016 (Copper, 2016). The copper smelting industry has grown and improved considerably since then, including continuing growth in China and modernization in Japan (Extraction, 2018). Outotec flash smelting and Outotec flash smelting/Kennecott - Outotec flash converting continue to be adopted while newer processes continue to be adopted in China. In addition, some of the world's original flash furnaces have been completely rebuilt (Extraction, 2018). This paper provides recent industrial production data and discusses these new developments. INTRODUCTION A world copper survey was redone in 2016 after a thirteen year lag since 2003. Some of the notable changes were the significant increases in production particularly from China. Since then, several smelters have gone through modernization processes and decommissioning of older technologies. This paper will review the notable changes since the last publication at Cu2016. In the last paper, Copper Smelting: 2016 World Copper Smelter Data, the author gave an audible sigh after observing that copper smelter sites as well as new and notable smelters have been spreading like wildfire in China since 2003. Indeed, seeing is believing. Figure 1 shows the Ningde Copper Smelter (double flashing, 400,000 MT Cu/Year capacity) that started up producing copper in 2018; Figure 2 shows the Nanguo Copper Smelter that is under construction with 300,000 MT Cu/Year capacity (first phase, side blown smelting and continuous top blown converting). We should not only admire the Chinese copper industry’s significant technological developments, but also the copper price support that it has provided throughout this century.

Jan 1, 2019

By P. J. Oakley, W. M. Thomas, S. W. Kallee, D. G. Staines

A Friction stir welding (FSW) is now extensively used in aluminium industries for joining and material processing applications. The (FSW) technology has gained increasing interest and importance since its invention at TWI almost 15 years ago. The basic principle, recent applications and the continuing development of the FSW technology are described. The paper will introduce some of the variants of FSW, such as Dual-rotation, Twin-stir(TM), and the Stir-lock(TM) technique.

Jan 1, 2006

By Q. Shi, Q. Feng

"The influence mechanism of chlorite on the flotation of pyrrhotite was investigated through flotation tests, Zeta potential measurements, optical microscope photos, solution ion measurements and absorption measurements. It is observed that, the addition of chlorite influences the flotation of pyrrhotite seriously. The IEP (isoelectric point) of pyrrhotite and chlorite is 7.6 and 4.3 respectively, in the condition of slight alkalinity, both pyrrhotite and chlorite are negatively charged, and the hetero-aggregation will not occur. With the existence of oxygen in solution, the iron ions are dissolved from pyrrhotite surface because of the oxidation of pyrrhotite during pulp conditioning. The dissolved iron ions adsorb onto the surface of chlorite in the forms of iron hydroxyl and iron hydroxide, and the adsorption results in the opposite charge of chlorite surface. As a result, the hetero-aggregation between pyrrhotite and chlorite occurs. The adsorption of chlorite changes the surface property of pyrrhotite and restricts the adsorption of amyl xanthate onto pyrrhotite surface, and then decreases the flotability of pyrrhotite.INTRODUCTIONIn sulfide ores processing, magnesium silicate bearing gangue minerals often report to the concentrate causing downstream processing problems as well as increased smelting costs. Talc,chlorite and serpentine are gangue minerals commonly encountered in complex sulfide ores (Engel, Middlebrook, & Jameson, 1997; Pietrobon et al., 1997; Witney & Yan, 1997; Chen, Grano, Sobieraj, & Ralston, 1999a, 1999b; Bremmell, Fornasiero & Ralston, 2005; Senior & Thomas, 2005; Wang, Somasundaran, & Nagaraj, 2005; WieseHarris & Bradshaw, 2007). All of them are characterized with uniform crystal structures consisting of silicon-oxygen tetrahedron and magnesium-oxygen octahedron. The magnesium-oxygen octahedron layers are broken during the liberation of serpentine to expose the magnesium-oxygen bonds with strong ionicity and hydration, which results in natural hydrophilicity of serpentine. In water, the hydroxyl on serpentine surface ruptures and dissolves into the aqueous phase while the Mg2+ remains, resulting in surface positive charge (Tao, 2012). As serpentine has a positive potential at alkaline condition, it is therefore likely that it will attach through electrostatic attraction to the negatively charged mineral surface and reduce both the flotation rate and recovery of target minerals (Lu et al., 2011). For talc, characterized as good natural hydrophobicity, the liberation comes from the interlaminar fracture to remain molecular bonds on surface with weak hydration. Being naturally hydrophobic, talc easily reports to flotation concentrates, thus reducing concentrate grade (Shortridge, Harris, Bradshaw, & Koopal, 2000; Beattie, Huynh, Kaggwa, & Ralston, 2006). Meanwhile, both molecular bonds and magnesium-oxygen bonds are exposed on chlorite surface when liberation occurs, resulting in moderate natural hydrophobicity between serpentine and talc (Tao, 2012). And thus the mechanisms of influence of chlorite on sulfide ores are more difficult to study."

Jan 1, 2016

By R. Kong, X. W. Zhang

"High pressure (up to 50 MPa) isotropic compression tests were performed on marble, gneiss and sandstone specimens, of which represents the typical rocks, to investigate isotropic compression deformation characterization at room temperature. Experimental data with respect to volume change in loading and unloading are presented. An apparent volume change inflection point (sensitive stress) was observed at a lower pressure range for porous sandstone, indicating that the elastic-plastic behaviour arising in the isotropic compression stage, but for tight crystalline rock, the sensitive stress is much higher, not probed prior to 50 MPa. The irrecoverable volumetric strain in the unloading can be seen for sandstone as well. The anisotropic deformation was discussed in terms of the axial and radial strain measurement. It was found that essential features of mechanical anisotropy are the irreversible in deformation range. The deformation feature in the isotropic compression tests is a very complex issue due to the factors concerning the stress history, unloading in sampling and in-situ stress. INTRODUCTIONThe isotropic or hydrostatic compression condition that stress is compressive and has the same magnitude for all direction, which is expressed as s1=s2=s3 in principal stress space. A yield locus of soils subjected to the isotropic and anisotropic compression was widely known, for instance Cam Clay model, which forms a closure cap model. However, the similar isotropic compression yield curves for rocks, especially for hard rock, was not established due to the geo-stress in the rock mass is much less than the socalled isotropic yield stress. And hence, the previous experimental studies on the hard rock have been made tend to on the stress-strain-strength relationship (Handin & Hager, 1957; Edmond & Paterson, 1972; Menéndez et al., 1996). Perhaps the yield curves related to an increasing in the hydrostatic pressure is not forced to construct for hard rocks, undoubtedly, the deformation data in this processing is valuable to assess the bulk module (Fabre & Gustkiewicz, 1997), anisotropy (Niandou et al., 1997), field stress (Hakala et al., 2007). Furthermore, many rocks store much elastic volume strain energy link to the hydrostatic pressure exerted, following a deviator stress applying, to drive the unstable brittle fracture for hard rock. Latter was studied to interpret the incentive of rock burst. However, volume change characteristic in the isotropic compression behaviour have been scarcely studied experimentally to our knowledge, less application related to the fracture in hard rock as well. The mechanical behaviour in the isotropic compression of hard rock is notably affected by the original structure anisotropy, stress history and stress condition before sampling, all of which need reasonably assess. It is also a useful understanding to study isotropic compression that elastic and plastic volume change in the isotropic loading and unloading, and the micro crack evolution throughout it."

Jan 1, 2015

By P. C. Sui

Numerical investigation and parametric simulations of the coupled electrical conduction and mass diffusion in the GDL of a PEMFC are reported. The coupled transport is solved using a 2D, "under-the-rib" computational domain for the cathode GDL. The current density on the GDL/catalyst layer interface, which constitutes one of the boundary conditions for the GDL domain and reflects the activation overpotential in the catalyst layer and the ohmic loss in the membrane, is solved iteratively using a novel numerical algorithm. A parametric study is performed to investigate the effects on current density distribution of various operating conditions such as oxygen concentration and membrane resistance, and of design factors such as GDL geometry, anisotropic transport properties, and deformation under the land area. The results show that the current density distribution under the land area can be dominated by either electron transport or mass transport, depending on the operating regime.

Jan 1, 2005