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We report the studies of Proton-Exchange Membrane Fuel Cells (PEM FC) and hydrogen storage materials at McMaster University for the last 14 years. From the initial investigation of ionic conduction mechanism to the revelation of the origin of non-Arrhenius temperature dependence, as well as the synthesis and characterization of high temperature polymer electrolytes, both experimental and theoretical works have been compiled for the fuel cell membranes. In addition to the discovery of suppressed ionic conduction in Electrode-Membrane Assembly (EMA) and novel hydrocarbon PEMs based on micro-emulsion, the first evidence of hydrogen adsorption saturation by carbon nano-tubes was also achieved, which has been the bottleneck for the application of PEM FC. Prior to our study, a number of controversial publications have claimed the hydrogen capacity of these materials to be between 0.1 to 10.0 wt.%, and none demonstrated a plateau of adsorption with pressure that is consistent with monolayer saturation. Others suggested that the tube bundle structure is opened under high pressure to enable higher adsorption on newly uncovered surfaces, but received no confirmation. Using our home made high-pressure instrument with in-situ electrical probes, we found that a plateau is nearly achieved at about 300 atm in the room temperature isotherm, and that nanotube bundles actually compress with pressure instead of splitting, using in-situ electrical measurements.

Jan 1, 2005

By T. S. Smith, C. C. Rennie

"THE LEAD-ZINC and tungsten mines of Canadian Exploration Ltd are on Iron Mountain, 8 miles south of Salmo, B.C., in the Nelson mining division. Relative location of the mines is shown on the general plan.First recorded lead production was in 1908 from surface outcrops. Small amounts of high lead ore were mined intermittently until 1926. No major lead-zinc production occurred until 1949 when outcroppings on the south side of the mountain were mined and diamond drilling began to prove the existence of a large replacement orebody. Lead-zinc ore has been mined continuously from the Jersey orebodies since March 1949, with monthly tonnage as high as 50,000 tons per month, but currently averaging 30,000 tons per month.Schee1ite-bearing tungsten ore was found in 1942 by H. Lakes in an old adit and open cuts at the north end of the Emerald tungsten orebody. The Emerald tungsten mine was developed by the Federal Government as a Wartime Metals project and operated for eight weeks in the fall of 1943, when the poor demand for tungsten closed the mine. Canadian Exploration Ltd. purchased the mine in 1947 and mined in excess of 100,000 tons in 1947-48 until the demand for tungsten dropped again and interest was centred on lead-zinc. The Federal Government repurchased and reopened the Emerald Mine in 195 L and built a new concentrator. The mine and mill were sold back to Canadian Exploration Ltd. in 1952.Regional Geology and IntrusivesThe host rock for both the lead-zinc and tungsten mineralization is the Laib formation of Lower Cambrian age, which consists of 400 feet of crystalline limestone underlain by beds of argillite, and argillaceous limestone locally altered to ""skarn"" or ""tactite"". The Laib limestone is overlain by black argillite and underlain by the Reno quartzite of Pre- cambrian age. Repetition of folded beds has allowed the interpretation of the large isoclinal fold which repeats the limestone (see general cross-section). Dolomitization and the associated lead-zinc ore have been found only in the right-side-up limestone and are not known in the overturned limestone.Two elongated stocks of granite cut the sediments. The Emerald stock outcrops along the east side of the Emerald tungsten mine and again west of the Jersey workings, while the Dodger stock outcrops only at the north end of the Iron Mountain. The shape and attitude of these bodies are believed to have been governed partly by pre-granite faulting and partly by pre-granite folding of the sediments. Although some forceful intrusion may have occurred the detailed granite surface indicates a gentle stoping emplacement."

Jan 1, 1949

By S. R. Amos, N. O. Lotter, A. L. Hannaford, J. F. Oliveira, D. W. Broughton

"Ivanplats Ltd appointed Xstrata Process Support to perform the flowsheeting development work for their hypogene and supergene geomet units of the Kamoa Copper deposit, located in the Democratic Republic of the Congo. Through systematic flowsheet development using modern Process Mineralogy, the optimised milestone flowsheet delivered a saleable concentrate grade of 32.8% Cu at 85.4% recovery with hypogene ore, and a saleable concentrate grade of 45.1% Cu at a recovery of 83.4% for supergene ore. The significant value of this development is that a single flowsheet will treat both hypogene and supergene ores and produce saleable concentrates. Further work to advance the flowsheet performance has been identified for investigation in the near future.INTRODUCTIONLocation and Description of the Kamoa DepositThe Kamoa copper resource is located some 40 km west of the city of Kolwezi, in the south west of the Katanga Province of the Democratic Republic of the Congo, in the region of Central Africa. Drilling at Kamoa in 2008-2009 had discovered laterally continuous, sediment-hosted, high-grade stratiform copper mineralisation in a newly discovered copper district that forms a previously unrecognised western extension of the famous Central African Copperbelt – which hosts such world-class deposits as Kolwezi, Tenke-Fungurume, Konkola and Nchanga. This discovery showed that the western end of the Copperbelt in the Congo does not terminate at Kolwezi (Friedland & Broughton, 2009). The resource contains hypogene and supergene geomet units with a transitional zone located inbetween the (upper) supergene and the (lower) hypogene. In the hypogene unit, the major copper sulphides are bornite, chalcopyrite and chalcocite, whilst in the supergene, the sequence is led by chalcocite, then bornite, and finally chalcopyrite. Covellite is present in both units as a minor copper sulphide. Both geomet units will be mined and treated in one concentrator, either as blends or as campaigns."

Jan 1, 2013

By C. Sui, J. E. Nesset, M. Li, J. Y. Kim, S. L. Chryssoulis

"A plant study of zinc rougher flotation at Brunswick Mining was conducted using lime, soda ash and a combination of both as the pH modifiers in order to establish the effects on sphalerite and pyrite kinetics and mineral selectivity. The plant sampling and analysis was augmented by surface analysis using TOF-LIMS, SEM and XPS as well as fundamental precipitation and surface-charge studies in the sphalerite Ca/C03/S04 system.The results revealed the important role of carbonate ions in cleaning the sphalerite surface for effective activation by CuS04 to occur, and the beneficial role of combined soda ash and lime in increasing pyrite and galena depression.1.0 IntroductionThe studies reported in this paper were initiated as part of an investigation into the causes of a particularly pronounced seasonal deterioration in metallurgical performance at the Brunswick Mining concentrator during the summer of 1995. The concentrator treats a complex base metal ore having a typical feed composition of 9.0% Zn, 3.5% Pb, 0.4% Cu and 100g/t Ag at a current throughput of 9,000 TPD, although at the time of the problem in 1995, the average production rate was closer to 10,500 TPD. Zinc, lead, copper and bulk (zinc-lead) concentrates are produced with overall metal recoveries of 86% zinc, 63% lead, 60% copper and 60% silver; results which are typical of the lower recoveries associated with fine-grained, highly complex VMS and SEDEX type deposits. The main economic minerals of interest are an iron-containing (7% Fe) sphalerite, galena and chalcopyrite with the main diluent (about 60% wt) being pyrite.Figure 1 shows a simplified flowsheet of the Brunswick milling circuit while the seasonal decrease in summer metallurgy in 1995 is illustrated in Figure 2. Of significance is the rapid drop in copper and lead recovery in June while there is an apparent delay until late August-September before the zinc deterioration reaches its lowest point. A more typical seasonal effect within the experience of the authors is the reverse of the Brunswick situation, namely an improvement in summer performance thought to be associated with improved differential flotation kinetics during warmer weather leading to better mineral selectivity. The historical Brunswick experience was particularly severe during the summer of 1995 with estimated incremental losses of $10 Million for this period. The potential of the very significant economic benefits to be gained from understanding and hopefully improving the annual drop in performance led to an investigation involving the minesite metallurgical group, the Noranda Technology Centre (NTC) as well as researchers in Professor Jim Finch's group at McGill and the surface analytical services and interpretive skills of AMTEL."

Jan 1, 1998

By Rick Collins

Presentation Agenda 1.Sudbury Basin 2.Diamond Drilling 3.Planned Production 4.Safety 5.Timeline 6.Sustainable Development 7.Scope Elements 8.Progress 9.Delivery Approach 10.Owners and EPCM Roles 11.Contract Styles 12.Mine Systems & Technologies 13.Q & A

May 1, 2009

By Chuck Crowell

ISO Standards ?Provide Information to Address Commercial and Safety Needs for Standardization: ?Definitions and Terminology ?Test Methods ?Performance Criteria ?Conformity Assessment Process ?Developed by Global Experts ?Promote Global Harmonization

May 1, 2013

By André Desbiens, Jocelyn Bouchard, René del Villar

"The metallurgical performance of the column flotation process is determined by the concentrate grade and recovery. Although the former can be continuously measured using an on-stream analyzer, the latter must be estimated by a material balance calculation based on seldom verified steady-state assumptions. Consequently, the automatic control and optimization of flotation columns should be performed using secondary variables having a strong influence on the metallurgical performance, such as froth depth, gas hold-up or bubble surface area flux and bias. The aim of this paper is to present a model-based automatic control strategy using froth depth and bias measurements obtained from virtual sensors developed at Laval University. Preliminary pilot plant results on two-phase (water– air) and three-phase system (water – minerals – air) will be presented and eventual industrial implementation of such a strategy as well as the possibility of achieving effective real-time optimization from bias and froth depth measurements will also be discussed.INTRODUCTIONFlotation columns have been widely studied and used in mineral processing for about twenty years. Although a great deal of work has been accomplished to understand the influence of different variables such as froth depth (H), bubble surface area flux (Sb) and bias (Jb) on the metallurgical performance, the measurement of some of these variables is still difficult to be performed – except at the laboratory level – because in most cases, no commercial device yet exists.As a result of this, it is almost impossible to achieve neither efficient control nor optimization of the process at the industrial level, even in open-loop operation. This paper aims at presenting a simple control strategy of froth depth and bias. Description of the sensors used to achieved measurements, preliminary pilot plant results for froth depth control, eventual industrial applications and possibilities for process optimization are also treated."

Jan 1, 2003

By Rob Stewart

Acknowledgements ? Josef Macek(Manitoba Geological Services) ? Sally Goodman (SRK) ? Inco Geologists ? Rogerio Montiero ? Thompson Mine Geologists Introduction ? Regional Geology ? Thompson Geology ? Stratigraphy ? Sulphide Characteristics ? Conceptual Model ? Structural History ? Belt ? Thompson Mine ? 1D Deposit ? Ore Controlling Structures ? Using Structural Data to Guide Exploration ? Summary

May 1, 2006

By I. Zhitomirsky, X. Pang

The outstanding thermal and chemical stability, excellent mechanical properties and biocompatibility of zirconia have made this material an important candidate for fabrication of advanced protective coatings on metals, graphite, carbon fibers and biomedical implants. Nanostructured polymer-ceramic composite films containing zirconia were synthesized on metallic substrates by combining cathodic electrosynthesis of inorganic particles with electrophoretic deposition of cationic polyelectrolytes. Thick crack-free oxide and composite coatings were obtained using this newly developed technique. The deposits were studied by thermogravimetric analysis, X-ray diffraction analysis, scanning electron microscopy and atomic force microscopy. The mechanisms of deposition are discussed.

Jan 1, 2004

By W. K. Gowans

The Sullivan Concentrator treats a complex sulphide ore consisting mainly of galena, marmatite and pyrrhotite. The ore carried minor values in silver, antimony, bismuth, indium and tin. The products of the concentrator are lead, zinc, iron and tin concentrates. The minor metal values other than tin are recovered from the concentrates by the refining processes in the smelter at Trail.The concentrator was completed in 1923 and first operated with a capacity of 2,500 tons per day. In the years 1926 to 1929 changes to equipment and buildings brought the operation up to 5,500 tons per day and then, in the years 1935 to 1945, the daily tonnage was raised to 8,500 tons. After 1945, the rising insoluble content of the ore made it necessary to consider the construction of a Sink-Float plant. At this time consideration was also given to the construction of a new crushing plant underground to replace the rolls crushers and cone crushers located at the concentrator. By 1949, construction of the Sink-Float plant was completed along with a new underground crushing plant, and an electric haulage way between the underground crushing chamber and the Sink-Float plant. The ore was hauled in forty 14-ton car trains which discharged into a 3,000 ton receiving bin by means of an air operated five car rotary dumper. With the start up of the,Sink-Float plant, a 1 ½ ft. by 12 ft. Hardinge rod mill was also brought into operation. The Sink-Float plant made it possible to treat 12,000 tons/day of mine run ore with up to 40% of this being rejected as float.

Jan 1, 1975

By P. E. Weidmark

"Energy, Mines and Resources Canada has published the first in a new series of reports that will examine selected mineral products that are imported.""Vanadium - An Imported Mineral Commodity"" looks at one of the 32 raw materials for which Canada currently is totally dependent on foreign sources of supply. Vanadium is used in Canada mainly as an alloying element in the manufacture of high-strength, low-alloy (HSLA) steels.The series will examine the supply systems for various selected imported non-fuel minerals, as an aid to developing policies that might lead to reduced dependence on external sources. Each report in the series will address a numberof questions:What countries do the mineral and its principal sub-products come from?How do they get to Canada?What are they used for?How vulnerable is the supply chain to disruption?Are there alternative sources?Are substitute materials available?In summary - how serious is Canada's supply problem for the mineral in question, and what should be done about it?Mineral Bulletin MR 188, ""Vanadium - An Imported Mineral Commodity"", is available for $3.00 ($3.60 outside Canada) from authorized government bookstore agents and many other bookstores, or by mail from the Canadian Government Publishing Centre, Hull, Quebec, KIA OS9."

Jan 1, 1981

By T. Haubold, K. Ortner, T. Jung, D. Roth-Fagaraseanu, C. Mattern

Application of integrally bladed disks (blisks) is of increasing interest in compressors of aero engines. Blisks are preferred due to their potential for size and weight reduction, for increased performance and for reduced manufacturing costs compared to conventionally bladed disks. Erosion of the blisk aerofoils in service reduces engine performance, and can result in short shop visit cycles. This significantly increases the life cycle cost of these components, particular when considering that eroded aerofoils can't be exchanged easily for blisks during refurbishment. Shop visit cycle times can be extended and maintenance costs can be reduced through the application of an effective protective coating. The ongoing development of an erosion resistant coating and deposition process suitable for coating complex blisk geometries is described here. The coating is a multilayered W /TiB2 system exhibiting superior erosion resistance compared to known single- and other multilayer concepts. A modified sputter process is used to enable coating even of blisk geometries with shadowed surface to competitive recurring cost.

Jan 1, 2006

By S. A. Sadough vanini

In this paper the influence of temperature on the flow behavior and rheological characteristics of an A356 alloy in the semi-solid state using backward extrusion process are studied experimentally and numerically. Simulation process is done by dynamic explicit in ABAQUS software for each forming condition. A cooling slope treatment was employed in order to obtain a non-dendritic microstructure. Experiments were performed in 5 temperatures and 4 different wall thicknesses. In the low forming speeds, liquid fraction had time to escape from solid phase forward the samples? wall. This condition was the main reason for the segregation phenomenon seen in the base and walls. Viscosities were determined using the force-displacement graphs obtained form back-extrusion tests. As observed experimentally, in a constant temperature, increase of shear rate resulted in decrease of alloy viscosity exponentially. Raising the temperature increases the liquid fraction hence reduces the semi-solid alloy viscosity. The results of experimental and simulation are compared and there is a good adaptation.

Oct 1, 2011

By S. McCarthy, K. E. Waters, A. Jordens

The beneficiation of rare earth (RE) element bearing minerals has become an active area of research as applications for these elements grow while the supply to non-Chinese consumers is restricted by export quotas. One of the most interesting beneficiation techniques for RE minerals is froth flotation as their unique chemistry suggests that collectors with a specific affinity for RE cations should be able to selectively recover these minerals. Existing literature, focusing mainly on bastnäsite flotation, identifies hydroxamic acids as excellent collectors for RE minerals. The high stability of hydroxamate-RE cation complexes is the explanation most often offered for the observed selectivity of these reagents in bastnäsite flotation however some research has also suggested that mineral solubility plays a crucial role in the success of hydroxamic acid flotation of RE minerals. This work investigates the interaction of allanite, a relatively insoluble RE-silicate mineral, with benzohydroxamic acid using zeta potential measurements and microflotation. The effects of Fe(III) and Fe(II) ions as potential activating ions (cations that form stable hydroxamate complexes) on benzohydroxamic adsorption to the allanite surface are investigated as a potential solution to promote hydroxamic acid adsorption. The results indicate that the optimum conditions for separation of allanite from quartz occur at pH 4 using FeCl2 as an activator for benzohydroxamic acid adsorption.

Jan 1, 2014

By B. Tanda

A process has been developed at Curtin University whereby glycine is used in an alkaline environment to leach gold, silver and copper from their ores, concentrates, process intermediates and wastes. Copper mineralisation investigated includes various oxides, sulfides and native copper. The leach process utilises an oxidising environment such as oxygen. Glycine is a non-toxic, non-volatile, edible, low cost reagent which is produced in large industrial quantities for use in several industries. Glycine and its copper and precious metals complexes are stable over wide pH, Eh and temperature ranges. Other than losses in leach residues, the glycine is recovered and recycled for leaching. Iron dissolution is insignificant in the pregnant leach solution. Iron in pyrite remains unaffected, whereas iron associated with base metal sulfides (e.g. chalcopyrite and bornite) is converted to a readily filterable iron hydroxide. Efficient separation of copper by solvent extraction and conventional electrowinning has been shown to be feasible for a number of organic extractants, whereas gold and silver glycinates adsorb very well onto carbon allowing CIP/CIL/CIC (carbon-in-column) based processes. The process is ideal for ores containing acid-consuming gangue, concentrates with high arsenic or halide contents and for copper-gold ores with significant sulfide mineralisation. The process eliminates many of the problems associated with the processing of copper-gold-silver ores, such as elemental sulfur formation, silica gels, unwanted metal co-dissolution, and jarosite precipitation. The reagents used and process residues are much safer and environmentally benign than conventional process options. The processing technology can be applied to in-situ, heap and vat, or agitated tank leaching at temperatures ranging from ambient to below 100?C at atmospheric pressure and is currently being commercialised. This paper will focus on copper leaching and recovery and iron rejection from a chalcopyrite flotation concentrate.

Jan 1, 2016

By D. Satish Kumar, D. Mazumdar

"95% bulk mixing times in three different size water model ladles of a 140 T cylindrical shaped , dual plug ( located diametrically opposite at mid bath radius position) stirred, industrial ladle were determined experimentally with and without an upper buoyant phase. Based on dimensional analysis and a regression of the experimental data and, it was shown that in the inertial and gravitational force dominated flow regimes, 95% bulk mixing times for a slag-less situation can be described via:[equation]Parallel to this, a large number of experiments were also carried out in one of the water models (D=0.30m) to quantify the influence of an upper buoyant phase on mixing. These indicated that mixing time, operating variables and thermo-physical properties of the upper phase liquid can be correlated via a dimensionless relationship of the type:[equation]in which, Q is the ambient gas flow rate, L is the depth of liquid , (AL) is the slag layer thickness and 6 and t are respectively the surface tension and viscosity of the upper phase fluid The dimensional analysis, regression of experimental data as well as the adequacy of the proposed correlations are discussed in the text."

Jan 1, 2004

By M. Cai

A practical simple method is proposed to estimate the tensile strength (st) of strong brittle rocks from the strength ratio of R= sc/st = 8 sc/sci, where sc is the uniaxial compressive strength and sci is the crack initiation stress in an uniaxial compression test. 8 is the Griffith strength ratio and the term sc/sci accounts for the difference of crack growth or propagation in tension and compression in uniaxial compression tests. sci can be reliably obtained from volumetric strain measurement or acoustic emission (AE) monitoring. With the strength ratio R determined, the tensile strength can be indirectly obtained from the result of uniaxial compression tests. In addition, a practical estimate of the Hoek-Brown strength parameter mi is presented and it is suggested that mi = 12 sc/sci can be applied to strong, brittle rocks in high confinement zone and mi = 8 sc/sci can be applied to low confinement to tension zones. It is found that the predicted tensile strengths and Hoek-Brown strength parameter mi using this method are in good agreement with test data. The rock strength parameters like st and mi, which require specialty tests such as direct tensile (or Brazilian) and triaxial compression tests for their determination, can be reasonably estimated from uniaxial compression tests.

May 1, 2009

By Colin E. Dunn

Plants have a remarkable ability to select, use and store metals derived from the substrate. Each species is unique in its requirements for and tolerances to the full spectrum of chemical elements in the Periodic Table. Studies to define the chemical characteristics of common trees and shrubs of the temperate forest are providing insight to their use for exploration, i.e., biogeochemical exploration. Examples of surveys over gold deposits in British Columbia show the effectiveness of sampling various tissues from different species in a range of biogeoclimatic environments. At the Nickel Plate mine in the Montane-Spruce zone, outer bark of Lodgepole pine was effective in defining a large area of metal enrichment; at the Carolin mine in the zone of Coastal Mountain Hemlock, analysis of twigs of western hemlock and Pacific silver fir provided an exploration target considerably larger than that defined by lithogeochemistry; at the Mount Washington gold deposit in the Mountain Hemlock zone, twigs of mountain hemlock and rhododendron were used to outline the mineralization; and in the Interior Douglas-fir zone at the QR deposit analysis of Douglas-fir tops collected by helicopter provided a rapid and effective method of identifying a gold-rich area.

Jan 1, 1995

By R. C. Reed, A. Akhtar

Oxidation of the third generation cast single crystal, nickel-base superalloy CMSX-10 is examined using isothermal tests at 900°C and 1000°C for times ranging from 20 hours to 100 hours. X-ray diffraction, scanning electron microscopy and energy dispersive secondary X-ray analysis were used to characterize the microstructure. It was found that the external scale formed at 1000°C is made up of (Ni,Co)O and the spinel NiCo2O4. The (? + ? ') microstructure of the superalloy transforms into the intermetallic (3 phase prior to the onset of internal oxidation. Internal oxidation results in the formation of (Ni,Co)Ta2O6 and (Ni,Co)WO4. No evidence was found for the formation of alumina (Al203), and the spinels NiCr2O4 and NiAl2O4 in this third generation superalloy. Results of the laboratory investigation are compared with those of an aero-engine turbine blade removed from service and examined earlier.

Jan 1, 2004

By H. Wilhelm, W. I. van Drunick

The Anglogold Ashanti (AGA) Navachab single stage SAG mill has provided an excellent setting for incremental optimization. Over the past decades, several interventions have resulted in marked improvements in specific performance; including steel ball scat removal, re-design of the mill lifters, replacement the pebble crusher and cyclone cluster, as well as the use of a vibrating screen in place of a discharge trommel. Recent initiatives now include an operating fine DMS circuit, studies on pre-crushing of the ROM feed and also fine-screening as an alternative to hydrocyclone classification. The current optimized state of the Navachab mill allows it to operate at approximately 20% higher efficiency when compared to mills of similar shell dimensions in gold mining, treating similar ore. This paper describes the systematic improvement of the SAG circuit to its current state.

Jan 1, 2012