Search Documents

By L. Sun

Recently, micro-tubular solid oxide fuel cells (SOFCs) have attracted the attention of many researchers because of their numerous advantages over larger tubular and planar SOFCs. These include excellent thermal shock properties giving rapid startup/shutdown capability, a high volumetric power density compared to larger tubular SOFCs, and reduced sealing problem compared to planar SOFCs. In order to screen cathode materials for micro-tubular SOFCs, the perovskite cathodes were deposited, using a variety of methods, on 10.5 mol % yttria-stabilized zirconia (YSZ) tubes. Their electrochemical properties were then evaluated by using electrochemical impedance spectroscopy and steady-state polarization methods, based on a three electrode configuration, and with the reference electrode position carefully optimized. The oxygen reduction reaction kinetics at the cathode/electrolyte half cell were then investigated in detail.

Jan 1, 2005

By Bert S. Hall

"The purpose of this paper is to review the evidence at hand concerning the earliest centuries of cast iron in Europe, from roughly 1400 A.D. until the second half of the sixteenth century. For the most part it is concerned with the relationship between two technologies which emerged first in China and then later appear in Western lands, gunpowder weapons and iron founding. We should not assume, as I hope to show later in this discussion, that weapons constituted the only product for which the iron founder had any market, but it is clearly true that attempts to produce weapons constituted the most severe technical challenge for the early founder. Firearms appear for the first time in Europe in the 1320s and develop into significant weapons on the field of battle by the end of the century. Theirs is a complex history, subject neither to easy summary treatment nor to simplified models of development. I hope to be able, through the analysis of the evidence concerning cast iron, to show that one important strand in the fabric of gunpowder's history concerns the materials from which cannon could be made. This question is subject to a number of shades of meaning, because ""cannon"" can be made for many purposes under a profusion of different names, and under sharply varying conditions of use. As a result, the question of materials is frequently really a question of competing materials, and involves a complex set of factors, of which production costs and the ultimate safety of the user seem the most important. Judged in this manner cast iron was an important but unsatisfactory metal for weapons purposes until 1543, at which time English founders learned to make iron muzzle-loading cannon which could rival bronze ordnance in most important performance criteria, but which cost much less to produce. With that event, the history of cast iron and the history of weapons entered into the close relationship that persisted until the advent of rifled artillery made of steel in the middle of the nineteenth century."

Jan 1, 1999

By Michel Gauthier, Jacque Trottier

"ForewordA symposium on base metal deposits was held in Bathurst, New Brunswick, from June 10-13, 1990, sponsored jointly by the Geological Surveys Branch of the New Brunswick Department of Natural Resources and Energy, the New Brunswick Prospectors and Developers Association, and the Geology Division of the Canadian Institute of Mining, Metallurgy and Petroleum. Papers prepared for the symposuim are being published as a series of articles in the CIM Bulletin. This third paper (the first was by Fyffe, et al., in Vol. 83, No. 938, the second is in this issue) in the series presents an overview of the tectonic setting and geochemistry of base metal deposits in the Eastern Townships of Quebec.ABSTRACTIt is well known that the classification system of volcanogenic massive sulphides (VMS) is based upon their metal content. This metal content, the result of hydrothermal solutions circulating within strata underlying the deposits, is generally thought to be related directly to two parameters: (1) the nature of the underlying stratigraphic sequence; and (2) the physico-chemical conditions that existed at the time of the hydrothermal event. Furthermore, these two parameters are, in turn, related to the tectonic setting. One must bear in mind that these parameters are diachronous and evolve with time. These factors are considered in our analysis of the major VMS deposits of the southeastern Quebec Appalachians. This analysis will describe the time and environment of formation of these deposits and integrate them into an evolving paleotectonic model.VMS deposits in the southeastern Quebec Appalachians formed during three distinct metallogenic episodes. During the first episode, which involved early closing of the Iapetus Ocean and associated destruction of oceanic crust by subduction processes(Early Ordovician?), cupriferous VMS deposits hosted by pillowed, mafic (boninitic) lava flows were formed in immature island-arc systems (""Cyprus-type"", e.g. Huntingdon deposit).In the second episode, which also occurred during the closure of Iapetus but at a later stage (Early to Middle Ordovician), mature island-arcs formed and hosted polymetallic VMS deposits (""Kuroko-type"", e.g. Eustis deposit).Finally, during culmination of the Taconic and/or Acadian orogenies (Middle Ordovician and/or Devonian), transtensional basins, associated with tholeitic to transitional mafic volcanism began to develop. Major sedimentation occurred contemporaneous with volcanism, and within this framework polymetallic VMS deposits were formed (""Besshi-type"", e.g. the Memphremagog deposit).Although incomplete, the proposed paleotectonic model represents the sequence of the tectonic settings that prevailed during the formation of the VMS deposits of the southeastern Quebec Appalachians."

Jan 1, 1991

By Z. S. Abisheva

The Zhezkazgan copper sulfide ore deposit in Kazakhstan contains both rhenium and the rare osmium isotope "osmium-187" (187Os) in the high isotopic purity of 99.4 ± 0.2%. This isotope is believed to have originated as a result of the disintegration of one of the rhenium isotopes, according to the reaction: 187Re75 ?> 1870576 + B- + v~ (where B is a 13-particle, v~ is a 3-disintegration antineutrino). The distribution of osmium and rhenium in metallurgical byproducts produced during the recovery of copper from these ores has been studied and process flowsheets for the processing of rhenium and osmium-containing byproducts have been developed.

Jan 1, 2007

By K. Fujita, T. Kikuchi, Y. Sakamoto

Ceramic fibers were classified as a category 2 carcinogen by The European U legislation. Therefore we developed non-fibrous insulating castable which utilizes n porous aggregate, which is composed of Calciumhexaluminate. Although at beginning we applied alumina cement as binder for non-fibrous insulating castable, kind of formulation had a poor resistance to spalling. We developed non-fibrous insulating castable without alumina cement. This solved a problem which pre\ formulation had a poor resistance of spalling. We applied a new non-fibrous insub castable for reheat furnace in steelworks, then we could achieve good result which condition equivalent to ceramic fiber insulating castable.

Jan 1, 2004

By H. Kuboyama

The synergistic effects of polymer additives such as gelatin and polyethylene glycol) (PEG) and Cl- on Cu electrodeposition have been investigated by measuring the polarization curves for Cu deposition, by rotating ring-disk electrode technique and by AC impedance measurements. The cathode potential for Cu deposition was greatly polarized in solutions containing both Cl- and gelatin or PEG, showing evident synergistic effect of polymer additives and Cl- on Cu deposition. The cathode potential was shifted to the less noble direction with increasing the concentration of Cl- in solutions containing polymer additives and showed the maximum polarization at Cl- concentration range between 0.1 and 1 mmol/L. The rotating ring-disk electrode technique revealed that Cu deposition in solutions containing small amounts of Cl- proceeded with initial formation of adsorbed intermediate CuClad. The Cole-Cole plots obtained by AC impedance techniques suggest that the reduction of CuClad is suppressed by polymer additives. The morphology of Cu deposited from solutions containing both PEG and Cl- showed the compacted surface composed of smaller grains due to an increase in the overpotential for Cu deposition.

Jan 1, 2007

By Anne-Laure Bonnet

Les connaissances acquises au cours des dernières décennies sur les gîtes de métaux de base et précieux intensément métamorphisés (p. ex. Vokes, 1991; Cornell et al., 1992; Zaleski et Peterson, 1995) ont permis d?élaborer des guides d?exploration pour de tels gisements dans les terrains de haut-grade métamorphique (Spry et Scott, 1986; Rubin et al., 1993; Hand et al., 1994; Spry, 2000; Spry et al., 2000). Un transfert de ces connaissances à la cartographie des vastes terrains gneissiques non différentiés de la province de Grenville permet d?affiner l?approche cartographique nécessaire pour reconnaître les systèmes hydrothermaux métamorphisés en terrains vierges et peu diagnostiques puis d?en discriminer les divers halos d?altération (Corriveau et al.,1996, 1997, 1998, 2003; Williamson et al., ce volume). Cette approche prend en compte les « empreintes métamorphiques » observées sur le terrain, telles que les variations des assemblages minéralogiques, du mode et de la composition des minéraux métamorphiques, pour reconnaître des roches présentant une composition inhabituelle caractéristiques de protolites altérés par hydrothermalisme. Ces empreintes citées cidessus sont facilement reconnaissables dans les terrains de haut-grade où la recristallisation induit un grossissement des grains qui permet de déterminer la nature et le mode des minéraux dès les levés de terrain. Cette approche raffine la compréhension des terrains de haut-grade métamorphique et illustre que leur complexité (i.e. polyphasage de la déformation et du métamorphisme) n?est pas forcément une limite à leur exploration. Elle a donc été utilisée systématiquement lors des levés de terrain réalisés dans le cadre d?un projet de l?Initiative géoscientifique ciblée de RNCan. La zone cartographiée se situe le long de la marge sudest du Groupe de Wakeham dans le secteur est de la Province de Grenville. Deux régions ont été plus particulièrement étudiées, celle du lac Musquaro (SNRC 12K10, 11 et 14) et la région côtière comprise entre Kégashka, La Romaine et Baie des Loups (SNRC 12K1, 2, 3 et 7) (fig. 1).

May 1, 2003

By C. A. Rowland

"Plant owners and operators, plant designers and grinding mill manufacturers are giving much attention to the design and manufacture of autogenous and semi-autogenous grinding mills, particularly the mills that have large diameters and draw power up to 10,000 hp and greater. Reliable designs giving long operating lives are required in today 's ore processing plants.This paper reviews bench-scale and pilot-plant testing to determine first if the ore is suitable .to be ground by these methods and then reviews the data obtained from pilot-plant testing that is used to select the mills and the grinding circuit. The paper then discusses the use of the pilot-plant results to design the mills. The most important pilot-plant data used for mill design are power and the amount of ball charge to be used. The mill size selected is a combination of these factors. Pilot-plant data not only establish power requirements, but can be used in the selection of the type of drive, variable speed or fixed speed, and the operating procedure to be followed. This leads into the mill control circuit to be used. The total charge in the mill, the type of drive and mill discharge arrangements are needed in the calculation of stresses and bearing loads. Conclusions reached from pilot-plant work are used to obtain data for process design, and autogenous and semiautogenous mill design should be part of any test program incorporating either or both of these grinding methods."

Jan 1, 1981

By G. J. Desroches

"In order to improve zinc plant productivity, areas of low efficiency were identified. As a result, solution purification was improved, additional dust precipitator capacity was made available and a new zinc casting plant was installed. The effects of these and other changes are discussed and the expenditure and benefits reviewed. HistoryThe operation of the Flin Flon metallurgical complex including an electrolytic zinc plant commenced in October 1930. The design of the zinc plant was based on that of the Commonwealth Mining and Smelting Company at Trail, British Columbia, the Anaconda Great Falls Montana Plant and the Electrolytic Zinc Company plant at Risdon, Tasmania.The plant began with a design capacity of 60 tons per day and currently produces 255 tons per day. Since plant start-up, approximately 3.5 million ton s of zinc metal have been produced, most of it exceeding special high-grade specifications.IntroductionThe facility incorporates the basic process steps of roasting, leaching, purification, electrowinning and casting. Figure I details the flowsheet. During the late 1970s, management recognized that in order for the zinc plant to continue operating, it was necessary to introduce cost-effective practices.Study groups, consisting of design engineers and operations personnel, were formed to investigate the details of plant revisions.The objectives were to improve productivity by reducing manual labour, reducing energy usage, increasing zinc recovery, increasing metal output and reducing costs.This paper details the changes made during the period 1979to 1986 and shows how these changes have affected the productivity and economics of the zinc plant operation."

Jan 1, 1988

By A. W. Johnston, R. E. Barrett

"The Central Patricia mine is in the greenstone belt north of lake Sc. Joseph in northwestern Ontario. It is 90 miles north of Allanwater on the Canadian National railway and 220 miles east of the Manitoba boundary. The unusual feature of the ore of this mine is that the gold does not occur in quartz but in sulphide minerals filling fractures in iron formation.AREAL GEOLOGYThe rocks of the area in which the mine occurs belong to the Early Precambrian. They consist · of andesite lavas and tuff interbedded with greywacke-like sediments and iron formation . A siliceous phase of the sediments lying north and south of the greywacke enclosing the ore-bearing iron formation in places resembles a sheared and sericitized quartz porphyry. This is shown in the legend of Fig. 1 as quartz porphyry and quartzite, but it is possible that the quartz porphyry-like phase is sediment. A northwest- striking dyke of diabase crosses the property 3,000 feet east of the shaft ( Fig. 1).IRON FORMATIONAlthough there are numerous bands of iron formation in the v1cm1ty of the mine, ore has been found to date in only one main and two lesser zones. The iron formation bands range in width from a few inches to 60 feet, and are interrupted along their strike by gaps that are parallel and rake to the east at about 65°. The iron formation is definitely banded and laminated."

Jan 1, 1954

By Hani S. Mitri

Strainbursts in brittle rock are common to deep underground mines. The state of stress at the boundary of mine openings is dictated by a biaxial stress/loading condition. This paper reports the results of a series of biaxial compression tests carried out on 100 mm cubic samples of norite rock, under different horizontal-to-vertical stress ratios. The results indicate that the biaxial compressive strength is considerably higher than the uniaxial one. It is found that the norite sample behaviour under biaxial loading mirrors field behaviour where shearing and progressive spalling of the opening boundary are observed prior to strainbursting. Sample failure is initiated by rock spalling at the sample free faces, i.e. in the plane of biaxial loading. Finally, it?s the out-of-plane shear failure mechanism that causes the sample to collapse. Shear failure takes place violently and abruptly and is accompanied with considerable audible noise.

Apr 1, 2005

By E. Contestabile, T. R. Craig

"This report describes the development and effective use of shaped charges as part of the Elliot Lake Mine Roof Stability Project to remotely remove the heads from roof bolts. With a slight modification, these same shaped charges are being recommended f or use to the Brunswick Mining and Smelting Corporation Limited (Mining Division), to cut steel cable bolts.IntroductionThe Canadian Explosives Research Laboratory (CERL) often receives requests to cooperate in solving problems encountered in private industry or other sectors of the government. CERL is equipped to design and test explosive and pyrotechnic devices and the policy is to treat each case individually.The first case reported evolved from a request from a sister laboratory at Elliot Lake. The intent was to remotely remove the head s of roof bolts as part of a mine roof stability project. The device designed for this use was 1000,70 effective in the laboratory and 80% effective in the mine.The second case reported results from a request from a private mining company knowledgeable of the Elliot Lake Project. Their requirement was to remotely cut cable bolts. This request was first treated as presenting a new problem. The solution, however, proved to be very similar to the former."

Jan 1, 1985

By A. Galibois, R. Singhal

"This paper highlights some of the potential application areas of knowledge-based systems in the mining industry. The basic theoretical principles associated with knowledge-based systems are discussed and the justification for mining applications is given. The paper concludes with a brief description of a prototype knowledge-based system applied to scraper selection that was developed at Université Laval on a LISP machine. IntroductionThe beginning of Artificial Intelligence coincided with the conception and development of the first computer systems some thirty years ago. At that time researchers were euphoric about the possibility of modelling the human reasoning process. Soon, however, they discovered that the combinatorial aspect of the set of possible solutions to a particular problem did not permit an in-depth evaluation.In the mid-60s researchers started to look at the heuristic approach because it was more suited to human behaviour with its congnitive abilities (i.e. representing, reasoning, problem solving and advising). The heuristic approach allows possible results rather than exact solutions and it is more rapid and cost effective than the exhaustive combinatorial analysis. The heuristic approach did allow some noticeable progress in the seventies with the development of the first expert system called MYCIN with the objective of diagnosing blood infection diseases."

Jan 1, 1988

By S. E. El-Alfy, John Starkey

"The Iron Ore Company of Canada treats up to 125,000 t/d of iron ore at its Carol Concentrator in Labrador City, NF.A complete water balance study in the concentrator was done to show how to reduce the consumption of fresh water, to improve metallurgy in the magnetic separation (mag) plant, and to help reduce maintenance costs for the reclaim water and tailing pumping systems.The study showed that more than 60% of the water used in the mill was internally recycled dirty water from dewatering cyclone overflows, and that water reduction was closely tied to the effective use of these internal reclaim pumping systems. In addition, new operating parameters were set for the 4 -15,000 USGPM reclaim water pumps which should save over $100,000 per year in maintenance costs.IntroductionThe study described in this paper was set up for the purpose of lowering water usage in the concentrator, and to reduce tailing and process water pumping costs (operating and maintenance). Another benefit was also expected, namely, to improve magnetic separation efficiency through better water and density management of magnetic separator feed streams.The procedures selected to perform this work were: ( 1) to prepare accurate, as built flowsheets of the entire iron recovery process, including fresh and process water systems, (2) to calculate normal material balances in all circuits at full production, (3) to use the computer spreadsheet model so generated, to evaluate specific ways to reduce water consumption and (4) to re-evaluate metallurgical performance and operating parameters in the light of this information.Overall control of the 28 spiral iron recovery lines was found to be excellent because automated start up and shut down of the individual lines had been incorporated in the design from the start. Because production rates can vary due to sales requirements, mine and mill maintenance delays and hardness variance, the mag plant (which treats spiral tailings) must deal with a wide variety of operating conditions. Good water management therefore is a key item in achieving high recovery of the fine free magnetite which is too fine for recovery in the spirals.In order to make the study as accurate as possible, process data for major flows was reviewed by metallurgical staff and then by mill supervisors. The operating picture of the concentrator so generated was judged to be a good estimate of the mill at full production. By changing key inputs, the variance of process water demand and tailing slurry produced for several other operating conditions were studied.The usefulness of this exercise has prompted this present presentation to be made. Older plants by nature have undergone many revisions as operators have worked through ore changes, market changes, labour cost increases and the availability of new equipment, to improve their operation. Sometimes therefore it is necessary to stop and reassess what is happening in a plant in order to continue the never ending work of process optimization. The techniques used here were ideally suited to the gravity/magnetic concentration flowsheets used, but there is no reason why similar studies could not be done in other process plants.The authors of this paper hope that this experience at IOC will be helpful to others who face similar challenges in the pursuit of excellence in their processing plants."

Jan 1, 1995

By B. Szpunar

Structural and mechanical changes of urania are investigated when oxidized to U3O8. The CASTEP ab-initio quantum mechanical program, employing density functional theory is used. The total energy technique is implemented to investigate changes in the lattice constants. The ab-initio calculations predict a 36% increase in the volume per uranium atom when transforming from UO2 to U3O8, which agrees very well with experimental data. The implication of this prediction on the linear expansion and fuel fragmentation is discussed. The calculated elastic constants of urania are in good agreement with experiment. The predicted mechanical properties of UO2 and U3O8 are compared.

Aug 1, 2010

By Stanley Davidson

"The ore deposit mined by Falconbridge Nickel Mines, Limited, is one of the numerous nickel-copper sulphide bodies marginal to the large oystershaped mass of differentiated norite in the Sudbury district, famous as the world's most important nickel producing field. The unique character of the ore deposits of the district has resulted in its intensive geological study over a period of more than 50 years. The results of these studies have given rise to a voluminous geological literature and to a great deal of controversy as to the genesis of the ores. This description of the structural geology at the Falconbridge mine is presented in the hope that it may form a small part of the chain of evidence leading to a reasonably satisfactory explanation of the ore genesis.The mine, named after Falconbridge township in which the deposit occurs, lies along the southeast margin of the norite mass, which, however, is h::re concealed beneath a deep mantle of glacial sands and gravels averaging over 100 feet in thickness. As a consequence, the deposit was not discovered by the early prospectors, and it was not until 1916-17 that E. J. Longyear, of Minneapolis, located the ore by drilling(ll). The discovery was foreshadowed in 1899 by the work of Thomas A. Edison, who found indications of the deposit by what is believed to have been a combination of magnetic and electrical geophysical surveys. He sank a prospect shaft over what has to date proved to be the largest and richest ore section in the mine. A wet quicksand layer at the rock surface proved impenetrable, however, and the 'Edison' shaft never reached bed-rock.The Falconbridge property was acquired by the Lindsley interests in 1928, and ore output, since its inception in 1929, has gradually risen from a modest beginning to the present 2,000 tons and more daily. Total production in this period is 7,500,000 tons of ore averaging 1.72 per cent nickel and 0.89 per cent copper, together with a small but valuable content of precious metals, principally of the platinum group."

Jan 1, 1954

By Makhlouf Boubahziz

The HNIA field is part of the Tinrhert project which consists of developing 17 fields containing essentially gas with a few small rings of oil. It is considered as one of the main fields in this project in terms of its area and the number of geological structures that has formed it. It is a wide anticline of Cambro-Ordovician age, orientated NNE-SSW and located in the South-eastern part of Illizi basin. This structure extends from Alrar-center in the North, to the North of In Amenas in the South. The area is 1350 km2. The main reservoirs forming HNIA field are the Devonian (F2, F3 and F4), Siluro-Devonian (F6) and Cambro-Ordovician. These latest are formed by 4 sandy units alternated by layers of shale and shaly silt termed from the base to the top as follow: Unit II, Unit III-3U, Unit IV-2L and Unit IV3; these units are the subject of this study. The HNIA field is essentially gas, up to day this field is at the stage of appraisal and evaluation in order to establish a development plan; therefore the main target of this study is to contribute to this frame work. The following objectives are: ?To build a structural model of the study area. ?To integrate all the sedimentological, structural and petrophysical data in order to build a 3D geological model

Aug 1, 2013

Accurately modeling and predicting long term mill throughput is one of the challenges facing metallurgists, geologists and mine engineers in their quest to consistently deliver accurate life of mine business plans. Batu Hijau has systematically improved long and short term mill throughput predictions since feasibility and commissioning in 1999. This has been achieved through a combination of ongoing improvement to the geology ore hardness and grade characterisation model, drill and blast optimisation and, by application of these data to model mill throughput. Batu Hijau has demonstrated the ability to consistently estimate long term mill throughput within ±2% accuracy. Aside from reliably predicting expected production rates with the existing plant configuration, this predictive ability provides a solid foundation for identifying operating and design criteria for short term grinding circuit optimisation and future expansions. This paper discusses ongoing throughput prediction model development at Batu Hijau based on geo-metallurgical characterisation. Also discussed are tools used for day to day production performance management. This includes on line "Mine to Mill" variable monitoring to improve operations parameter ecision making and performance assessment.

Nov 1, 2011

By F. Wirfiyata

"Accurately modeling and predicting long term mill throughput is one of the challenges facing metallurgists, geologists and mine engineers in their quest to consistently deliver accurate life of mine business plans.Batu Hijau has systematically improved long and short term mill throughput predictions since feasibility and commissioning in 1999. This has been achieved through a combination of ongoing improvement to the geology ore hardness and grade characterisation model, drill and blast optimisation and, by application of these data to model mill throughput.Batu Hijau has demonstrated the ability to consistently estimate long term mill throughput within ±2% accuracy. Aside from reliably predicting expected production rates with the existing plant configuration, this predictive ability provides a solid foundation for identifying operating and design criteria for short term grinding circuit optimisation and future expansions.This paper discusses ongoing throughput prediction model development at Batu Hijau based on geo-metallurgical characterisation. Also discussed are tools used for day to day production performance management. This includes on line ""Mine to Mill"" variable monitoring to improve operations parameter decision making and performance assessment."

Jan 1, 2012

By M. Timberlake, A. J. Jonaitis

"The DENVER Tube Press is a simple, high pressure (1500 PSI (100 bar)) filtration unit, developed for processing difficult-to-dewater materials and to produce a handleable filter cake and clear filtrate product.Lab and Pilot testwork conducted in Australia on coal fines (55-70% -35 micron (400 mesh)) have shown that total moisture contents of less than 20% are consistently achieved in the final cake products from the Tube Press.currently, these coal super fines are sent to waste due to uneconomical mechanical dewatering methods, which were only able to reduce total moisture levels in excess of 30%. Calculated, throughput rates for the 500 series Tube Press exceeded 1700 kg/hr (3750 lbs/hr). Feed solids concentration requirements are between 45 and 50% to achieve these results.INTRODUCTIONThe DENVER Tube Press is an automatic membrane high pressure filter press, which operates at hydraulic water pressures up to 1500 PSI (100 bar). The Tube Press was developed in the late 1960's by Charlestown Engineering, st. Austell, Cornwall, England, formerly a division of English China Clays, Ltd., to address more effective methods of moisture reduction of micron-size china clays. The Tube Press reduced moisture sufficiently to produce a hard surface-dry, handleable cake and clear filtrate discharge, which was recycled into the process. This development work was conducted using a 200 Series Tube Press (200 mm diameter x 2500 mm long filter surface)."

Jan 1, 1993