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By M. Xian, M. Jahazi, Y. L. Lin

The 2-mm butt joints of ZE41A-T5 sand castings were laser welded at different defocusing distances on two surface conditions (as-cast or machined) using a continuous wave 4 kW Nd:YAG laser system at a power of 2.5 kW and a welding speed of 6.0 m/min. Two welding modes (conduction or keyhole) have been observed. The adjustment of defocusing distance can greatly influence the establishment of conduction or keyhole modes. On the machined surface conditions conduction welding is obtained at a power density of 4.0 x 105 W/cm2. In contrast, keyhole welding is reached at a threshold irradiance of 1.5 x 106 W/cm2. Neither conduction nor stable keyhole modes have been established at a range of power density from 7.7 x 105 to 1.2 x 106 W/cm2 on the machined surface conditions. On the as-cast surface conditions keyhole is obtained at a power density as low as 4.0 x 105 W/cm2 but good surface quality is obtained at a defocusing of +2 mm. The as-cast surfaces require lower power irradiance for the formation of keyholes indicating that they have higher energy absorptivity for Nd:YAG laser beams probably due to coarse surface morphology.

Jan 1, 2004

By Rodolfo Zanella

Au/TiO2 catalysts were prepared by deposition-precipitation using NaOH (DPN) (~3 wt % Au) and urea (DPU) (~8 wt % Au), and calcined at various temperatures between 100 and 400 °C. They were characterized by UV-Visible, XANES, EXAFS and TEM. Their activity were tested in the reaction of CO oxidation at 5°C. After preparation, the gold species are in the oxidic state III. They begin to transform into metallic gold under air at ~100 °C for DPN and ~150 °C for DPU. At 200 °C, all the gold is metallic for the two preparation methods. The particle size increases from 1.5 to 3.5 nm with the calcination temperature. The catalytic activity for CO oxidation increases with the percentage of metallic gold, and it is maximum at 200°C for both types of samples. The activities (per mole of Au) are the same for the two types of catalysts. At higher temperatures, the catalytic activity drops. The decrease of activity is mainly due to a change of particle shape with the calcination temperature rather than to the increase of the particle size. At a calcination temperature of 200°C, the particles present small facets with rounded parts, and their outer surface contains a large proportion of low coordinated sites (steps and corners) while at high temperature of calcination, they are truncated octahedra with smooth facets.

Oct 1, 2003

By A. W. Jacobs

SHORTLY after Denny, Robson, and Irwin(l) published their first paper, in 1937, on the prevention of silicosis by metallic aluminium, experiments were begun on the practical application of the discovery. It was thought at that time that aluminium powder, to be effective in aluminium therapy, would have to be intimately admixed with siliceous dust at the latter's source. There followed several years of experimental work underground, during which the application of aluminium powder was tested in: (1) Shakers on machine columns, vibrated? by drills (2) Vials placed in drill holes to be blasted (3) Both homogeneous and heterogeneous. mixture with explosives ( 4) Packages with tamping (5) Compressed-air lines (6) Special compressed-air ejectors for use while drilling and after blasting (7) The discharge of ventilation fans (8) The filters of respirators It was concluded from this research that any adequate method of introducing aluminium powder into a mine atmosphere would require too much extra gear, supervision, and aluminium powder, and would interfere unduly with underground routine. Later, animal experiments by Denny, Robson, and Irwin(2) showed that aluminium powder provided effective therapy when inhaled independent of silica dust. Therefore, some means of surface treatment was deemed more practical.

Jan 1, 1944

By Hiwa Salimi, Foley. Stephen R, Loghman Moradi

Common water-miscible organic solvents including DMSO, DMF, methanol, ethanol, acetone and THF in combination with HCl and low concentrations of H2O2 were investigated for dissolution of gold. THF showed the best result demonstrating that gold powder could be completely dissolved in 1.5 hours in 1.0 mol/L HCl and 0.2 mol/L H2O2. No complete gold dissolution was observed for the rest of solvents even after 24 hours. The rate of gold dissolution was measured by dissolving gold wire in THF/HCl/H2O2 mixture. The rate of gold dissolution in optimised condition was 75 g m-2 h-1 at room temperature and significantly increased to 590 g m-2 h-1 by raising the temperature up to 60 oC. Although a THF/HCl/H2O2 mixture showed a slower dissolution rate in comparison with aqua regia, however the applied conditions are considerably milder which is highly promising for gold leaching in an industrial scale.

Jan 1, 2015

By Hämäläinen M., O. Hyvärinen, E. Jääskeläinen

HydroCopperTM is a new hydrometallurgical process for the treatment of copper sulphide concentrates, which has been developed by Outokumpu. The process includes chloride leaching of copper concentrate, solution purification and precipitation of copper(I) oxide, an intermediate product, which is reduced and cast into copper products. The reduction can be carried out by pyrometallurgical methods or hydrometallurgically in an autoclave. This paper discusses the thermodynamic and kinetic aspects of the hydrogen reduction of copper(I) oxide in an autoclave. The results of the laboratory tests are presented and discussed. Finally, the autoclave method is compared with other options.

Jan 1, 2004

By M. T. Ho, D. E. Wiley

The iron and steel industry accounts for almost 5 % of the total world CO2 emissions. Optimisation of the steelmaking process has led to significant reductions in the energy intensity to the point where it is now close to the thermodynamic limit. Further reductions are not likely to be achieved with efficiency improvement alone and will require the development of novel or breakthrough technologies. This paper will show the costs of implementing CO2 capture at direct atmospheric emission points for a number of iron and steel production processes. These include a conventional process, top gas recycling processes, the Corex and Hismelt smelt reduction processes and the Midrex direct reduction process. Depending on the point source emission, costs of capture with existing chemical absorption technology at iron and steel plants can be similar to capturing CO2 at pulverised coal fired power plants.

Jan 1, 2015

By P. C. Santos-Munguía, F. Nava-Alonso, O. Alonso-González

"The gold recovery of a Mexican cyanidation plant, in Sonora, has been decreasing due to the increasing presence of gold tellurides. This work presents the results of different processes aimed to recover the remaining gold from the cyanidation tailings of the operation. The cyanidation in the mine is performed at 0.1 g/L NaCN and pH = 10.3, adjusted with lime. The treatments studied in the laboratory with these tailings were: cyanidation at higher cyanide concentration than that used in the plant, cyanidation with oxygen injection, cyanidation with oxygen and lead nitrate addition, and thiourea leaching. The results obtained with each of these treatments are presented and discussed with the final objective of proposing a method to recover the gold associated with tellurium.INTRODUCTION It has been demonstrated that gold telluride is refractory to the conventional cyanidation process and, for this reason, some alternative methods to recover precious metals from tellurides have been proposed. (Zhang et al., 2010). These include cyanidation with modified conditions or the use of non-cyanide leaching agents. This work presents the gold leaching results of tests performed with a sample of cyanidation tailings obtained from a Mexican deposit containing telluride species. The mine exploits a mesothermal deposit with a molar Te/Au ratio of 1, containing also lead, molybdenum, bismuth and tungsten. Gold is recovered from the ore by standard cyanidation, however, lately the gold recovery has decreased, likely due to the tellurium content of the ore. The sample used in this work was the cyanidation tailings of this deposit. It was treated in the plant by cyanide heap leaching (0.1 g/L NaCN, pH = 10.3 adjusted with lime). Some gold remained after the cyanidation and it was thought that this gold was associated with tellurium. The objective of this work was the recovery of the remaining gold from the tailings by an alternative process."

Jan 1, 2017

By D. A. Barr

"Most of the lode and placer gold production in the Canadian Cordillera has been derived from mines and placers in the Intermontane and Omineca belts. Gold has been produced from rocks of Precambrian to Eocene age, but the preferred host environment contains Upper Paleozoic to Upper Jurassic eugeosynclinal or arc-type sedimentary and volcanic rocks adjacent to plutonic complexes which have a wide variety in both size and composition. Auriferous quartz lodes occur in fissures and shear zones which are commonly subsidiary to strong fault zones. In common with most vein-type deposits, structural complexities are an essential part of the mine environment.Gold production from the Canadian Cordillera to the end of 1978 totals 35.0 million ounces, of which 47 per cent has been produced from placer mining, principally in the Klondike and Cariboo districts. The balance has been derived from lode gold (80 per cent) and base metal (20 per cent) mines.Gold reserves in producing mines and deposits committed for production as of January 1, 1978 were 87.4 tons, or 21.6 per cent of total Canadian gold reserves contained in all types of deposits. Although more than 100 lode mines have operated in the Canadian Cordillera since the turn of the last century, over 75 per cent of the lode gold produced by 1978 was recovered from five mining camps, namely the Rossland, Hedley, Bridge River, Premier and Barkerville.The average grade of the principal producers in these camps was about 0.45 ounce of gold per ton. Individual camps yielded from 3 to 8 million tons during their operating lives, which varied from 28 to 43 years. The last of these mines ceased operating in 1971.Most of the total lode gold production has been derived from quartz veins, frequently with associated carbonate and ankerite, occupying fractured and faulted zones in Mesozoic volcanic and sedimentary rocks closely associated with a variety of intrusions. A review of the literature suggests that several deposits may have evolved by remobilization of ore constituents from earlier concordant gold-bearing formations. The principal metallic minerals in the deposits are native gold, electrum, tellurides, pyrite, arsenopyrite, pyrrhotite, sphalerite, galena and chalcopyrite.As the mineralogy suggests, many of the Cordilleran lode gold deposits have yielded important co-products or byproducts, including silver, copper, lead, zinc, cadmium and tungsten. Significant by-product gold production has also been derived from porphyry copper, volcanogenic, replacement and pyrometasomatic deposits, particularly in recent years.No major lode gold discovery has been made in the past 67 years, although little exploration activity for gold has taken place during the last 30 years. Several relatively small lode gold and gold replacement deposits have been discovered in recent years, either serendipitously (Chappelle) or on very low initial budgets (Northair and Carolin). Based on well-established precedents, one or more of these may eventually be developed into a large mine.A detailed study of the Canadian Cordillera gold deposits based on recent genetic models could prove rewarding, not only in up-dating information on their origin and depositional characteristics, but in stimulating the search for undiscovered gold deposits, in the Cordillera and other parts of Canada."

Jan 1, 1980

By J B. Magee

Sheep Creek Mines Limited has developed several operating techniques that have greatly assisted in keeping unit costs at reasonable levels. Some of the techniques, as described in this paper, include organization, accounting, warehousing, bonus and contracts. INTRODUCTION THIS paper is a non-technical report on operating techniques developed by Sheep Creek Mines Limited at their Mineral King mine, located near lnvermere, B.C. Depressed metal prices and continually rising labour and materials costs have necessitated a continuous search for method to keep operating costs down. The newly developed techniques and practices have greatly assisted in maintaining unit costs. Sheep Creek Mines Limited is a mining company incorporated under the laws of the Province of British Columbia. The Company's share capital is 3,500,000 common shares, witl1 a par value of 50 cents each, of which there are 1,875 000 shares is-sued. The Company has eight di-rectors. The administration, exploration and accounting offices are located in Nelson, B.C. The Company's working capital is approximately $1,500,000.

Jan 1, 1963

By L W. Morley

The Division is concerned with physical methods as applied to geo-logical research and mapping. An at-tempt is made to describe long-term goals, illustrated by examples of projects in the fields of aeromagnetic interpretation, palaeomagnetic re-search, Pleistocene and groundwater geophysics, seismic surveying, electromagnetic research and instrument development. Cooperative projects in surveys and research, with universities, private companies and provincial organizations, are frequently undertaken. An outstanding example of this is the recently approved Federal-Provincial Aeromagnetic Survey Plan, the purpose of which is discussed both from an economic and a scientific point of view. HISTORY OF THE DIVISION M AGNETIC, electrical, seismic and gravity methods, as a means of extending the geologist's sphere of observation beyond the head of his hammer, came into wide-spread use for the first time after World ?war I. Interest in these methods was aroused amongst geologists of the Geological Survey and, in 1928, a group of these geologists and university

Jan 1, 1963

By Francoi Robert, Andre J. Audet, Alex C. Brown

"The Sigma gold deposit is in a band of deformed metavolcanic rocks that are cut by an irregular mass of porphyritic diorite and by narrow undeformed feldspar porphyry dykes. The gold is in veins consisting mainly of quartz and tourmaline with minor pyrite, carbonate, chlorite, scheelite and free gold. The results presented here concern the structural setting of the ore and are based on a study of the mode of emplacement.Two principal types of veins have been recognized: subvertical and oblique veins. Both types are contemporaneous, mechanically linked and postdate regional deformation. The sub-vertical veins are composed of numerous mineralized lenses that occupy the central part of ductile shear zones of great lateral and vertical extent. Normally, several lenses occur in the same shear zone. The vein material seems to have resulted from incremental filling of openings by repeated vertical movement along rupture planes developed in the central part of the shear zones.The oblique veins are small elliptical lenses of ribboned vein material which formed essentially by progressive vertical opening of oblique fractures. Two types of oblique veins are known: one is restricted to feldspar porphyry dykes, within which they are arranged in an en-echelon fashion; the other is of greater extent and is not restricted to one rock type, but tends, however, to occur in the more competent porphyritic diorite.Vein orientation and mode of formation suggest that both sub-vertical and oblique veins developed during progressive deformation associated with the formation of the ductile shear zones. The latter probably formed in response to a compression that took place late in the tectonic history of the host rocks at Sigma."

Jan 1, 1983

By O. A. Ojo, E. Anisimov, A. K. Khan

Electro-spark deposition (ESD) has recently generated a great deal of interest in processing aerospace materials. This is due to its potential for joining and repairing difficult-to-weld precipitation strengthened nickel-based superalloys without having problems of welding cracking that often plaque these materials. The short duration of current pulses involved in the process combined with the intermittent contact results in extremely rapid thermal cycle that produces nearly no heat affected zone in the substrate material. The microstructure of electro-spark deposited superalloy was meticulously studied in this work by scanning electron microscopy (SEM) and analytical transmission electron microscopy (TEM). The results show that in contrast to general assumption, the extreme rapid cooling rates involved in the ESD process did not produce partition-less solidification that is devoid of second phase microconstituents in the material. The secondary microconstituents were found formed along the intercellular regions of the solidification microstructure. The nature of these particles and the possible implication of their formation on mechanical properties of ESD processed material are reported and discussed.

Jan 1, 2015

By Shintaro Takamiya, Kazunari Yoshida

"Recently, small sized micro-needles for medical are required more frequently by patients. The biggest reason is that it presents great burden on the patients, due to the size of the needle injection. People need to use a very small needle to lower the pain, but the downfall is that it makes them more expensive due to their complicated manufacturing method. Therefore, we need to fabricate a needle by wire-drawing to decrease its price. Tube-drawing is beneficial for its production value; however, in conventional tube-drawing it is difficult of control the wall thickness of the tube and makes it 1mmor lower in diameter. That is why, we propose fluid-mandrel drawing for new tube drawing. This method allows fabrication of a fine tube by using the pressure of the fluid in the tube. In this research, the goal is the fabrication of a fine tube by fluid-mandrel drawing and its evaluation. Finally, the fabrication of a fine tube by fluid-mandrel drawing was conducted and in result a tube with a diameter of 0.2mm, high strength and thin wall and fine inner surface was drawn, which can be used as a lesser pain micro-needle.INTRODUCTIONThe main manufacturing method of the current medical needles is roll forming. With this method, it is difficult to make a tube with a diameter lower than 1mm. Deep drawing has been proposed and used as method to further reduce the diameter, but this method is costly and the injection needle obtained by this method is several times more expensive.Therefore, we need to obtain a fine medical needle by drawing process that can be mass-produced and inexpensively manufactured. However, with the conventional drawing process, it is not possible to obtain a syringe needle with a reduced diameter easily, that is why, a fluid-mandrel drawing has been proposed which can reduce the diameter without damaging the inner surface. The methodology of the method is, a fluid is filled in the sealed tube and the pressure inside the tube during drawing is responsible for the good inner surface and wall thickness. It is also expected that the fluid can be easily discarded and that the tube can be manufactured on a long scale."

Jan 1, 2017

By Franc R. Joubin, Donald H. James

"THE PROPERTY of Rexspar Uranium and Metals Mining Co. Limited is situated within 3 miles of Birch Island, British Columbia, a village on the C.N.R. main line 80 miles north of Kamloops. The claims extend up the south slope of the North Thompson River valley.Prospecting in the area dates back many years. Fluorite was reported in 1918, lead showings in 1926, and bog manganese in 1929. Diamond drilling in 1942-43 indicated more than a million tons of material containing 20 per cent fluorite and 15 per cent celestite in what is known as the 'fluorite zone'. Marketing and beneficiation difficulties have delayed further development of this deposit.Systematic checking of specimens and drill core by the B.C. Department of Mines and the Geological Survey of Canada revealed low radio-activity in the fluorite zone material. Subsequent prospecting with Geiger counters revealed zones of higher radioactivity a few hundred feet distant from the fluorite zone. The property at this stage came under the development direction of Technical Mine Consultants Limited, who undertook a program of diamond drilling. Of the several radioactive zones located, two have so far rewarded development and appear to constitute low-grade uranium orebodies. These are referred to as the ""Black Diamond"" or ""BD"", and the ""A"" zones -see section. Open-pit mining of the thick, dip-slope orebodies appears possible.General GeologyWalker (1) describes the local rocks as metamorphosed sediments cut by granodioritic intrusives and by greens tone. At the property the sequence is:GreenstoneUnconformity or intrusive contact Trachytic member -tuffs, breccia, flows. Argillite -black, thin, not always present. Schist -thin-bedded sericitic quartzite and siltstone with some calcareous layers."

Jan 1, 1949

By Y. Nishida, Y. Nara, T. Ishida

Understanding time-dependent deformation and fracturing in rock is essential, because the information of the long-term stability of rock is required for many sub-surface structures excavated in a rock mass. Time-dependent fracture propagation has been invoked as a potential key mechanism responsible for the increase in seismicity preceding earthquake ruptures. In engineering projects and in preventing natural hazards, the study of time-dependent fracturing is necessary. Subcritical crack growth is one of the main causes of time-dependent fracturing in rock. For silicate rocks, subcritical crack growth has been investigated by various researchers. It has been clarified that surrounding environmental conditions (temperature, humidity, and existence of water) have strong influence on subcritical crack growth in silicate rocks. Therefore, the information of subcritical crack growth in silicate rocks has already been enough. On the other hand, information of subcritical crack growth in carbonate rocks is not enough. Especially, the influence of surrounding environment on subcritical crack growth in carbonate rock has not been clarified yet. In this study, we investigate subcritical crack growth in carbonate rock experimentally using a fracture mechanics testing method. Marble obtained in Skopje in Macedonia is used as a carbonate rock sample. The Double Torsion method is used to measure the crack velocity and stress intensity factor. Especially, influence of water on subcritical crack growth in Macedonian marble is investigated. It was shown that the crack velocity in water is much higher than that in air at the same temperature. Based on the results of subcritical crack growth measurements, the long-term strength is evaluated for marble. It was clarified that the long-term strength in water is lower than that in air in marble. It is concluded that water has a remarkable influence on subcritical crack growth in marble. It is also considered that the long-term stability of carbonate rock masses should be ensured in a dry environment.

Jan 1, 2015

By Francoi Robert, Andre J. Audet, Alex C. Brown

"The Sigma gold deposit is in a band of deformed metavolcanic rocks that are cut by an irregular mass of porphyritic diorite and by narrow undeformed feldspar porphyry dykes. The gold is in veins consisting mainly of quartz and tourmaline with minor pyrite, carbonate, chlorite, scheelite and free gold. The results presented here concern the structural setting of the ore and are based on a study of the mode of emplacement.Two principal types of veins have been recognized: subvertical and oblique veins. Both types are contemporaneous, mechanically linked and postdate regional deformation. The sub-vertical veins are composed of numerous mineralized lenses that occupy the central part of ductile shear zones of great lateral and vertical extent. Normally, several lenses occur in the same shear zone. The vein material seems to have resulted from incremental filling of openings by repeated vertical movement along rupture planes developed in the central part of the shear zones.The oblique veins are small elliptical lenses of ribboned vein material which formed essentially by progressive vertical opening of oblique fractures. Two types of oblique veins are known: one is restricted to feldspar porphyry dykes, within which they are arranged in an en-echelon fashion; the other is of greater extent and is not restricted to one rock type, but tends, however, to occur in the more competent porphyritic diorite.Vein orientation and mode of formation suggest that both sub-vertical and oblique veins developed during progressive deformation associated with the formation of the ductile shear zones. The latter probably formed in response to a compression that took place late in the tectonic history of the host rocks at Sigma."

Jan 1, 1983

By The Staff

Introduction It is the purpose of this paper to discuss a number of the metallurgical improvements in the technology of copper-nickel ore treatment which have been introduced during recent years in the plants of ?the International Nickel Company of Canada, Limited. In common with other ore treatment processes, the procedure for extracting nickel and copper is changing almost continuous! y. These changes are necessitated by reason of changes in ore grades and characteristics, rising material and labour charges, and the constant drive to maximize metal recovery and to minimize production costs. It is not possible to present a comprehensive list of all the changes made, and only a selected number of the improvements in the milling, smelting, and refining operations are covered. It should be clearly understood that some phases of the procedures described have been pioneered by others in kindred fields and due acknowledgment is given to their foresight and efforts. Articles have been published over the years describing the operations of the International Nickel Company plants and the reader is referred to the Engineering and Mining Journal, Vol. 130, No. 9, November 10th, 1930, and to the Canadian Mining Journal, Vol. 58, No. 11, November, 1937, and Vol. 67, No. 5, May, 1946. Other references are the Transactions of this Institute, 1932, 1938, and 1946; Metals Technology, American Institute of Mining and Metallurgical Engineers, February, 1938, and Canadian Chemistry and Process Industries, April, 1940.

Jan 1, 1948

By John F. Dougherty

Recently, there has been much debate as to the relevance of reporting financial results using the conventional accounting systems, which is based on historical costs, during a period of rapid inflation. In the following paragraphs , the symptoms, if not the causes, of inflation, its detrimental effect on the financial soundness of business in general and the financial reporting changes being advocated to overcome perceived weaknesses in the present financial reporting system in accounting for the effects of inflation will be reviewed. Finally, a course of action as a sound approach to the financial reporting problem will be recommended.

Jan 1, 1978

By H. Al-Kazzaz

The effects of laser power and joint gap on the welding quality of 2-mm butt joints of ZE41A-T5 sand castings were investigated using a continuous wave 4 kW Nd:YAG laser system and 1.6-mm EZ33A-T5 filler wire at a welding speed of 6 m/min and surface defocusing. The smooth weld profiles with the minor welding defects were obtained at a laser power of 4 kW and joint gap of 0.3-0.4 mm. The hardness values in the fusion zone are similar to those of the base metal but there is a drop in the heat-affected zone after a natural aging of 18 months.

Jan 1, 2006

By R. A. King, B. G. Hunt, C. E. T. White

"This paper reviews the history, occurrence, properties, and uses of indium, and describes the commercial production and fabrication of that metal by The Consolidated Mining and Smelting Company of Canada, Limited (Cominco), at Trail, B.C'. Indium is produced commercially at Trail from dross retreatment furnace D.R.F.) slag, a complex by-product of the lead smelting operations. Furnace feed prepared from this slag is smelted with coke and limerock in an electric furnace. The e1ectric furnace bullion is parted electrolytically, producing a market-able lead-tin alloy containing about 8 per cent tin, and leaving the indium in the anode slime. Recovery of indium from the anode slime involves roasting the slime with sulphuric acid, followed by leaching with water, purifying the leach solution, recovering the indium by sponging with zinc or aluminum, and re-fining electrolytically. This process yields standard grade (99.97+ per cent) indium which is either sold or refined •to high purity ( 99.999 per cent) indium for special uses requiring higher purity metal."

Jan 1, 1959