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By M. Piboule et J. M . Charbonneau, C. Picard

In the western part of the Chapais syncline (Abitibi-east, Quebec), the lava flows belonging to the Haliy Formation separate in two distinct sequences. The basal sequence contains prophyri tic metabasalts of calc-alkaline af f inity overlain by porphyritic metatrachyandesites and metatrachytes of alkaline to shoshonitic affinity. The upper sequence contains porphyritic metabasalts similar to those of the basal sequence along with highly potassic metaandesites trending to a subalkaline affinity. A geochemical study of trace and REE elements established that the composition of these lava flows results from a mixing or contamination process. The primitive tholeiitic liquids which are enriched in LREE were modified by the addition of a crustal contaminant enriched in Y, Zr, Th and K20. The magmatic liquids resulted from successive steps in the admixing process, evolved by fractionated crystallization. The mechanism of gradual admixing seems to be the major cause of the observed ea le-alkaline characteris ties and may also be the cause of the alkaline to shoshoni tic affinity in those lavas. The tendency to differentiation by fractional crystallization reveals the tholeiitic character of the primitive liquids.

Jan 1, 1984

By J. Laganiere

A considerable part of the sulphuric acid requirements of the Aluminum Company of Canada's Arvida smelter comes from the burning of 180-200 tons per day of zinc '"'sulphide concentrates in a 22-ft.-diam-eter fluidized bed roaster. The plant and its operation were fully de-scribed in a publication that appeared about ten year ago (1). A simplified flowsheet of the roasting and gas-cleaning sections of the plant is given in Figure 1. The wet zinc sulphide concentrates are un-loaded into a pug mixer, by means of a Pay loader, and mixed with water in a mixing tank to make a slurry of 80 per cent solids. The slurry is transferred to a .feed tank and then introduced into the roaster at a point four feet above the constriction plate, which is the height of the settled bed of zinc calcines. The roasting temperature is con-

Jan 1, 1963

By Bahaa Hussein

Considerable number of methods and procedures has been introduced for trending and progress reporting of engineering, procurement and construction projects. This paper introduces a novel method, designed to augment the set of indices for measuring schedule performance. The concept behind the developed method is to provide early warning by dynamically evaluating the schedule cumulative impact of construction projects. The proposed method is designed to highlight the gradual deterioration in schedule status resulting in a cumulative impact due to the aggregation of small delays encountered during the execution of non-critical activities, and can be used as an add-on utility to existing software systems that perform CPM scheduling. The proposed method is based on a developed formulation for quantification of the Schedule Compression Index, which takes into consideration the remaining project activities durations. The index is developed based on periodic comparisons of ?Current Schedules? and the project ?Baseline Schedule? using the summation of the remaining activities durations. A numerical example is presented to demonstrate the application and capabilities of the developed method. It is expected that the developed index together with other schedule performance indices would be of value to decision makers and members of project teams.

Aug 1, 2013

By François Robert

"The Eastern Abitibi Sub province (Quebec segment), contains two main types of gold deposits: the common quartz-vein type and the rare pyritic type. Both occur in areas dominated by volcanic rocks and are spatially associated with major fault zones.Quartz-vein gold deposits consist of simple to complex networks of quartz-carbonate-pyrite veins in reverse shear zones and extensional fractures. They occur in areas dominated by mafic volcanic rocks and are commonly associated with small syn- to late-tectonic porphyritic felsic intrusions. Associated alteration, which postdates peak metamorphism, is dominated by carbonatization, sericitization and pyritization of the wallrocks. These deposits formed late in the geologicalevolution of the Abitibi.Pyritic gold deposits range from deformed massive sulphide lenses to zones of syntectonic pyrite-rich veinlets and associated pyrite disseminations. These deposits occur in environments dominated by felsic volcanic rocks that are typically converted to sericite schists near the deposits. The associated pre-metamorphic aluminous alteration is now characterized by metamorphic sericite, andalusite, kyanite and chloritoid, overprinted by a late retrogression of alumino- silicates. These deposits probably represent deformed volcanogenic massive sulphide deposits, but the timing of gold introduction in these is not fully understood.The differences in geological attributes reflect significant differences in the genesis these deposits: the pyritic deposits probably have a multistage genesis, including a pre-tectonic stage, in contrast to a single stage late-tectonic genesis for the quartz-vein deposits.RESUMELa partie Est de la Sous-Province de l’Abitibi( segment québécois) renferme deux types de gites d' or: ceux de type ""veine de quartz"" et ceux, plus rares, de type ""pyriteux"". Ces deux types se trouvent dans des secteurs particulièrement riches en roches volcaniques et mantrent une association spatiale avec des zones de failles majeures.Les gites de type ""veine de quartz"" correspondent à des réseaux de complexité variable de veines de quartz-carbonate-pyrite se développant dans des zones de cisaillement inverse et des fractures de tension. Ils se concentrent dans les régions dominées par des roches volcaniques mafiques et s’associent fréquemment à de petites intrusions porphyriques felsiques syn- a tardi-tectoniques. L’altération associée ace type de glte est postérieure à la phase majeure du métamorphisme et consiste en une carbonatisation, une sericitisation et une pyritisation des épontes. La mise en place de ces gites est tardive par rapport à l'évolution géologique de l'Abitibi.Les gites d' or de type pyriteux consistent en des lentilles de sulfures massifs déformes, des zones d' abondantes veinules pyrite uses syntectoniques, et des zones de pyrite disséminée. Ces gites se retrouvent dans des empilements contenant surtout des roches volcaniques felsiques qui sont transformées en schiste à séricine pres des gisements. L’altération a l’umineuse pre-metamorphique associée a ce type de glte a donné naissance, lors du metamorphisme regional, a la sericite, a 'andal ousite, a Ia lcyanite et au chloritoi""de; par la suite, les alumino-silicates ont été affectes par une alteration retrograde tardive. Ces gites representent probablement des depOts de sulfures massifs volcan gènes déformes, mais la chronologie de la mise en place de l'or dans ceux-ci est encore mal comprise.Les caractéristiques géologiques propres à chacun de ces types de gites reflètent des conditions de formation différentes: le type ""pyriteux"" montre une histoire génétique polyphasée, incluant une étape pre-tectonique alors que le type ""veine de quartz"" s’est développe au cours d’une seule phase tardi-tectonique."

Jan 1, 1990

By A. G. Roach

HISTORY AND LOCATION SEAL HARBOR GOLD MINES, LIMITED, was incorporated in January, 1934, to take over 116 acres of mining lands in the Stormont gold district, Guysboro county, Nova Scotia. The nearby ten-stamp Mulgrave mill was also purchased, and since that time 974 acres of adjoining properties have been secured from the Government by direct lease. The property is served by a motor road and is about two miles from the village of Goldboro, situated on the shore of Isaac's harbour. The bulk of ?the supplies are brought in by coastal steamer from Halifax, a distance of about 100 miles, since the nearest railway connections are at Antigonish, some 40 miles distant. EARLYY WORK The Seal Harbor properties include the old Partington and Beaver Hat mines. A small tonnage of ore was mined from each and treated on the properties in stamp mills, which were later torn. down . A survey of old records shows that this ore averaged about $8.00 gold per ton. Development work by the present Company was confined to the 100-foot level until February, 1935, but after that rime the incline shaft was deepened to 425 feet and the 300-foot level was explored east and west of the shaft. Six belts of ore were intersected to the west of the shaft. The ore from these belts was hand sorted and the ore portion was put through the 10-stamp Mulgrave mill to defray operating expenses and to serve as a sample of the deposits. The average recovery per ton from this sorted ore was $6.10. Samples of the ore were sent to the testing laboratories of the Mines Branch, at Ottawa, and of Canadian Industries, Limited, at Toronto. Recommendations from both of these authorities were for removal of the coarse gold by concentration and barrel amalgamation, followed by cyanidation of the residue.

Jan 1, 1937

By B. W. Steele

"Dofasco began operations in 1912 as a steel foundry located in Hamilton, Ontario. Today, Dofasco is a fully integrated mill that manufactures hot rolled, cold rolled, galvanized and tinplate steels. Customers include the automotive, construction, tubular, manufacturing, appliance, packaging and steel ser-vice centre industries. Raw steel production and purchased semi-finished steel processed in1994 was 3.5 million net tonnes. Dofasco employs 7300 people at its Hamilton facility.Environmental management at Dofasco is guided by its environment policy and associated commitments. This paper discusses Dofasco’s responsibility for its products as it relates to these commitments. Dofasco is com-mitted to:n the principles of sustainable development that require that activities be conducted in a manner that provides for the present without compromising the ability of future generations to meet their needs. These principles will be integrated into product design, manufacturing and business planning;n managing renewable and non-renewable resources through the responsible application of reduce, reuse, and recycle principles;n minimizing any potential impact of its operations and products on the environment, employees, customers and the community;n continuous improvement of the effectiveness and integrity of our environmental management systems;n developing understanding among all employees about their responsibilities, and assigning the necessary authority; andn meeting the standards set by relevant legislation and international agreements through participation with governments and the diligent application of economically feasible and scientifically sound methods and technologies."

Jan 1, 1996

By A. M. Richmond

Introduction The apparent commonplace, and prosaic, nature of building-stones, lime, cement, gypsum, and clay products, and many other miscellaneous non-metallic minerals, such as abrasives, barite, diatomite, magnesite, mica, slate, salts, etc., and their everyday appearance and necessary in our lives, has removed much of the glamour, romance, and speculative attractiveness so frequently associated with our gold, silver, lead, zinc, and copper mining ventures. However, it will be readily appreciated, with but a brief study of the thirty-five or more non-metallic minerals and products which are mined, prepared, or are known to occur, in British Columbia, that the 'industrial minerals' industry in the Province has an abundance of interesting technical problems, is fraught with speculative possibilities, and, as such, fully deserves much more technical attention than it has hitherro received. The brief notes presented in this paper show, in summary form, the magnitude of the British Columbia industrial and non-metallic mineral industry; outline in synoptically form the principal deposits of non-metallic minerals presently known; and indicate in a general way a few of the possibilities which exist in the Province for the expansion of the industry. For convenience in presentation, the assembled material has been divided into four sections: 1.-Sraristical information 2.-Strucrural non-metallic minerals 3.-Miscellaneous non-metallic minerals 4.-Non-Metallic mineral possibilities in British Columbia 1. -Statistical Information The writer does not propose to dwell at length on the statistical comparisons and deductions which may be drawn from the four tables which have been compiled for this section of the paper, nor is it considered essential, as the figures present a most emphatic story in themselves.

Jan 1, 1935

By K. Svens, M. Lahtinen, L. Lehtinen

"Outotec's direct leaching process is an atmospheric leaching process for sulphidiczinc concentrates. The direct leaching process, based on special leaching reactors developed by Outokumpu and leaching know-how, is the most economical way to produce electrolytic zinc. The newest industrial-scale application of Outotec's direct leaching process will be started up in 2008 in China at Zhuzhou smelter. The process isintegrated to the existing production plant, replacing part of the old production facilities by modern technology and increasing the production capacity significantly. The process equipment supplied by Outotec includes also tailor-made reactors designed on the basisof the work and experience of Outotec Research Centre."

Jan 1, 2008

By Marcelle A. Hauseux

"The Turgeon Lake granite lies 5 miles north of Baie Johan Beetz, Quebec, at the eastern margin of the Grenville Province. The rocks are classed as granites, granulites, quartzites, biotite schists and gneisses, and amphibolites. The granite's uraniferous character is manifested by phosphuranylite, uraninite, and metamict .zircons associated with magnetite. Field anomalies occur in irregular pods, conformable with the tectonic foliation, in bands roughly paralleling sedimentary bedding. Associated features diagnostic of uraniferous granite are smoky quartz, brick-red feldspar, magnetite and a coarse to pegmatitic grain size. The granite is chemically and physically heterogeneous. Metasediment-granite contacts are diffuse or sharp, and usually conformable to bedding. The regional foliations within all rock types are coherent, and sedimentary structures are often preserved within both metasediments and granite. Autometasomatism probably was a strong granitization agent.A uranium reconcentration into fold-axial zones from original sediments which have been highly granitized during at least two phases of folding is suggested from the available data."

Jan 1, 1977

By Frank E. Lathe

During the war the National Research Council at Ottawa sent out questionnaires to the managers of nearly all the industrial plants in Canada. Inquiry was made as to the research equipment possessed, the number of research workers employed and the nature of the research problems which still remained unsolved. Practically all the companies reported that they had no special facilities for research, had no re-search workers and did not require the assistance of the National Research Council-because they had no research problems. Perhaps we have here one of the chief reasons why certain of our manufacturers find themselves unable to meet foreign competition. For hundreds of years the Indian tribes of northern Chile worked, in a small way, the copper deposits at Chuquicamata. They had no research problems and made no striking success of their mining operations. Then came an American company with a research problem, which they proceeded to solve. To-day the stock of that company has a market value of about $140,000,000.

Jan 1, 1926

By Franz Xaver Spachtholz

K+S Potash Canada GP (KSPC) is part of the K+S Group, one of the world's leading suppliers of standard and speciality fertilizers and the world?s leading salt producer. Globally, the K+S Group employs more than 14,000 people. The K+S share ? the only commodities stock on the German DAX index ? is listed on all German stock exchanges. Legacy, K+S Group?s most recent project, is a greenfield solution potash mine and production plant in the south of the Canadian province of Saskatchewan. Therefore K+S will invest 4.1 billion CAD. With the expected commissioning in summer 2016 the company projects to reach the two-million-tonnesmark of production capacity at the new location at the end of 2017. The gradual extension of the annual capacity to 2.86 million tonnes of potash products will occur afterwards. The Legacy Project will be Saskatchewan?s first new potash mine in nearly 40 years. It is one of the world?s most economically attractive potash projects. The project will contribute to Saskatchewan?s growth through employment, tax revenues, utilities, and local partnerships. Located in the southern part of Saskatchewan?s potash belt, the deposit is too deep to be mined conventionally due to rock mechanics and high temperatures. Legacy will therefore be a solution mine. Proximity to the urban centers of Regina and Moose Jaw is imperative, with their workforces and economy, as well as access to highways, railway carriers and, most importantly in the prairies, water. With this unique project setting and mining technique, we are convinced that Legacy will be one of the most efficient, economic, sustainable and safe potash facilities in the world.

Aug 1, 2013

By Frédéric Bélanger, George P. Demopoulos, Pascal Coursol, Thomas Feldmann

"The use of scandium in industrial applications is expected to rise in the coming years, in large part due to the expected adoption of new, clean energy technologies such as solid oxide fuel cells or Sccontaining high strength aluminium alloys. Given that the supply of Sc is currently dominated by only a few countries (Russia and China) other sources for scandium extraction need to be investigated. This paper looks at different options for the recovery of scandium from waste solutions generated during the production of TiO2 pigments via the chloride process route. In particular, a direct solvent extraction (SX) approach and possible options for concentrating scandium before the SX step were investigated. It was found that the presence of Ti during solvent extraction causes severe formation of stable emulsions, which can complicate the successful application. This was particularly a problem after multiple contacts of the organic phase with fresh aqueous phase. On the other hand it was noticed that the presence of certain elements in the solution, e.g., iron, could possibly be utilized to concentrate scandium in a solid precipitate.INTRODUCTIONMany newly developed high-tech products depend on the use of chemical elements that are only produced in very small quantities. This can result in high and fluctuating prices, as can be seen from Figure 1, which may cause substitution with inferior alternatives, if possible at all (Reck & Rotter, 2012; US Dept. of Defense, 2013; Whittaker, 2011). One example is scandium (Sc) a member of the extended rare earth element family. There are only a few scandium ore deposits, but most Sc is produced from the processing of by-products of other metallurgical processes (Melcher & Wilken, 2013). Increasing demand for scandium metal and oxide (Sc2O3, scandia) is coming from its increased use in applications such as ceramic lasers (Li, Ikegami, & Mori, 2005; Rainer et al., 1982), high strength aluminium alloys (Lathabai & Lloyd, 2002) as well as solid oxide fuel cells (SOFC) (Thijssen, 2011). Especially, the spread of climate friendly SOFC’s, which are a commercial product today (Bloom Energy, 2014), is expected to be a main driver for future Sc2O3 demand. However, the rate of market penetration of this green technology depends on the availability of high purity Sc2O3 (>99.999%), since it specifically contributes to longer life-time and better safety of the SOFC’s (Bloom Energy, 2014; Irvine, Politova, & Kruth, 2005)."

Jan 1, 2016

By A-A. Bogno, M. Rappaz, J. Valloton, H. Henein

"Rapid solidification of Al-Cu droplets of eutectic composition was carried out using Impulse Atomization in an argon atmosphere, to study the microstructures forming at different cooling rates and undercoolings. Two distinct morphologies were observed within the investigated Al-33wt%Cu droplets microstructures: (i) A regular lamellar morphology and (ii) an undulated morphology. The volume fraction of each type of morphology was measured as a function of the droplet size and the nucleation undercooling was deduced using the hypercooling limit equation. The scale of the microstructures was determined through measurements of inter-lamellar spacing across and along the growth direction. Growth velocity and undercooling were deduced using Jackson and Hunt (1966) eutectic growth theory. Finally, mechanical properties were estimated through micro-hardness analysis using a Vickers hardness tester, revealing exceptional properties for an aluminum-copper alloy. Indeed, the hardness values, increasing with growth rate and undercooling, were 3 times higher than the values obtained in hypo-eutectic Al-Cu alloys.INTRODUCTION Eutectic alloys are very attractive due to their good fluidity allowing ready shaping of parts in casting processes as well as in thermal spray deposition. In addition, they yield microstructures with high mechanical properties, by the virtue of their scale/size which is defined by the solidification parameters and the thermodynamic and thermophysical properties of the given alloy. Therefore, it is important to understand the relationship between the microstructures and the solidification parameters of eutectic alloys in order to control their solidification path and mechanical properties. The latter could be improved by either adding an appropriate strengthening component to a base eutectic material (Böyük, MaraslI, Kaya, ÇadIrlI, & Keslioglu, 2009) or by refining the microstructures for more effective dislocation pinning (Campbell & Campbell, 2003). Tailoring the microstructure can also be beneficial to chemical (Freitas, Osório, Spinelli, & Garcia, 2014; Osório, Freire, Caram, & Garcia, 2012) or electrical (Kaya, 2012) properties of the material. Eutectic-type microstructures, usually formed from liquid (eutectic transformation) or solid (eutectoid transformation), are made up of two or more different phases, generally of lamellar or fibrous (rod like) morphologies (Kurz & Fisher, 1998). In general, a binary eutectic structure can be regular (when both phases are non-faceted) or irregular (one of the two phases is faceted), the two solid phases having roughly the composition of the liquid from which they are formed."

Jan 1, 2017

By Egon Berger

"In recent years the trend in underground metal mining has been toward ever increasing blasts (often in excess of 100 000 tonnes per blast). The Canadian mining industry has been in the forefront of these developments (VRM, LBHand cable bolting to stabilize the surrounding rock /avoid dilution).In order to move these large tonnages, efficient loading systems have to be developed. This paper shows the technical and economic implications of various loading scenarios based on a predefined (however typical) stoping layout by:1 . discontinuous loading using scoop trams;2. discontinuous loading using scoop trams in combination with low profile dump trucks;3. continuous loading (based on loading performance/operating costs of the AL-60) in combination with low profile dumptrucks.The cost advantages of production concentration (loading large tonnages from one drawpoint}, made possible by continuous loading as opposed to sea tiered mining (small tonnages), using discontinuous loading in tunnelling will be presented, based on actual results obtained in a decline development project using the A L-60 continuous loader. At as pacing oj150m between turning bays, it was found that continuous loading was out performing discontinuous loading in approximately80% of the overall decline development.Fuel consumption and total cycle times are compared, and a cost assessment is presented.INTRODUCTIONThe subject of this paper deals with the introduction of continuous loading in underground metal mining and single heading tunnelingContinous mining has been widely introduced both in underground and surface coal mining. Mechanized longwall mining, utilizing moveable shield supports in combination with double drum- shearers, has resulted in a tremendous increase of coal production per working face.This has led to very concentrated mining operations. In a typical German coal mine two mechanized longwalls nowadays would produce the same amount of coal as 12 to 15 longwalls in the 1950s. One longwall in a South African coal mine has recently set a world record with 120 000 tonnes of coal in a single month.In underground metal mines-often due to the irregular nature of the ore body and the mining methods used-mining is far less concent rated. Ore is often produced from a large number of stopes and production sections. Sometimes, a substantial amount of ore may be obtained from development in the orebody (40070 at a German base metal mine)."

Jan 1, 1989

By Carl Edmunds

Talk Outline Deposit?s Vital Statistics and Economic Environment Regional Geologic Setting Deposit Geology UBC Research Search Model and Current Exploration Plans Kemess Operations Kemess South Mine Mining rate (2006) ?135,000 tonnes / day Mill throughput (2006) ?52,000 tonnes / day Average Annual Production ?300,000 oz gold and 75 million lbs copper ?Production until mid-2009 Kemess North > Open pit reserve 423.8 million tonnes @ 0.3 g/tgold and 0.18% copper > 4.1 million ounce gold reserve (127 tonnes) > 1.45 billion pound copper reserve (636,000 tonnes) > 0.75:1 Strip Ratio

May 1, 2006

By R. Llewellyn

"Wear damage is responsible for very high maintenance costs and significant production losses in the oil sands industry of northern Alberta.It affects all areas of operations and involves a panoply of wear mechanisms from low stress sliding abrasion at extremely frigid temperatures during winter mining, to elevated temperature erosion/corrosion in processes where bitumen is converted to lighter hydrocarbon products.There is no universal panacea to defend against such diverse attack and a wide selection of resistant materials and systems is employed. These range from relatively soft rubbers which rely on their elastic properties for their protective capability, to some of the hardest ceramics and cermets which are currently available commercially.Details are presented of the characteristics and forms of the variety of wear materials being used and how they relate to the requirements of their areas of application. The review focuses on the practices followed at Syncrude Canada Ltd., which is the larger of the two commercial oil sands plants."

Jan 1, 1997

By Maurice A. Roche

Introduction Most of the Flin Flon ore-body, like many others in northern Canada, was covered by water. The original discovery was made where the ore-body outcropped on a strip of land jutting out into Flin Flon lake. The outcrop could be traced for a distance of 600 feet across the strip of land, but disappeared under the lake on both sides of the peninsula. Following the discovery or location of the property, in 1915, and subsequent to its examination by the H.P. Whitney interests in 1925, an extensive diamond-drilling programme was completed, which proved the existence of an ore-body at least 2,600 feet long and 900 feet deep. In plan, the central part of the ore-body at surface attains an overall width of about 450 feet; including waste horses, and gradually becoming narrower to the south. To the north, it stretches out as a much narrower tongue. The main body is a solid sulphide ore containing gold, silver, copper, and zinc. Adjacent to, and on the footwall side of, the solid sulphide ore-body, there are considerable widths of talcy disseminated copper ore, particularly in the upper 300 feet of the deposit, where the maximum widths occur. The ore-body occurs in a greenstone area, the rock being quite hard on the hanging-wall side, with the footwall schisted, talcy, and much softer. The greater part of the ore-body was overlain by 12 to 15 feet of water and from 15 to 90 feet of mud and clay, this material requiring eventual removal, regardless of the system of mining adopted. The total of mud and clay overburden was estimated at 1,000,000 tons. After considerable study, it was decided to mine the upper 300 feet of the ore-body by open-pit methods; the balance of the ore to be recovered by underground mining . The present paper gives an account of the methods adopted in both operations, and of the problems encountered.

Jan 1, 1935

"Yara Siilinjärvi in Finland is the Western Europe's only apatite mine. Annually it produces one million tons of apatite concentrate, which creates 10 million tons of tailings. At the beginning of 2017, Yara replaced their conventional TSF with a new tailings treatment plant, which increased the solids content of the slurry from 45–48% to 66–68%, making it possible to deposit as a paste. This extended the life-span of the current TSF from 2020 to 2035. This paper presents the storyline of the Yara paste plant project. The project began with laboratory testing and then progressed to pilot-scale thickening and beaching trials. After successful pilot trials, the final process design was implemented. Process automation played a key role in the project. An advanced control system is needed to maintain process stability and the desired operation point in various operational circumstances. Since commissioning the paste plant has been running consistently with an underflow solids content of 66-68%, with average beach slope angles of 3.5 degrees in the tailings disposal area. Robust thickener operation also leads to the trouble-free high-density pumping and high availability of the plan. During first year of operation the plant’s availability has been very good, over 97%, and currently, the plant is operated remotely from the main concentrator plant.INTRODUCTION The Yara Siilinjärvi Plant is owned by Yara International, a Norwegian fertiliser company. Yara Siilinjärvi is Western Europe's only apatite mine, and it primarily produces apatite concentrate for its Siilinjärvi phosphoric acid plant. A portion of the concentrate is also dried and shipped to other Yara fertiliser plants. The site annually produces one million tons of apatite concentrate, which creates approximately 10 million tons of tailings. Extending the lifespan of the 1150-hectare tailings storage facility has been studied in Siilinjärvi for a long time. The aim has been to use the same tailings area footprint, without any new land purchases or major dam increases. An important part of the process has been to study the possibilities for using new technologies, especially thickened tailings technology (Ruhanen, 2014)."

Jan 1, 2019

By M. H. Fathi

The aim of this work was to prepare the metallic coatings on 316L stainless steel dental implant and evaluate the corrosion characteristics and thus the biocompatibility of the uncoated and metallic coated dental implants and comparison of the effect of the type of coatings on biocompatibility. Three types of metallic coatings including Tantalum, Niobium, and Titanium coatings were made using physical vapor deposition process on 316L stainless steel dental implant. Structural characterization techniques including; X-ray Diffraction, Scanning Electron Microscopy and Energy Dispersive X-ray Analysis were utilized to investigate the microstructure and morphology of the coatings. Electrochemical potentiodynamic tests were performed in two types of physiological solutions at 37±1 °C in order to determine and compare the corrosion characteristics. All three types of metallic coatings had a positive effect on improvement of the corrosion behavior so that the coatings could increase the corrosion resistance of 316L stainless steel and this trend was independent to the type of physiological environment. Biocompatible metallic coatings could decrease the corrosion current density that is a distinct advantage for prevention of ion release. This can improve the biocompatibility of the implant and, consequently prevention of tissue damages, inflammation and irritation and obtained desirable histopathological response.

Jan 1, 2007

By A. Romero

"Most underground mines require heating or cooling systems to meet health and safety standards in the working areas. In regions where daily or seasonal fluctuations of environmental conditions exist, these systems tend to be over-sized and operate at low average load factors, which increase both investment and operating costs. One possible approach to reduce the temperature variations of the fresh air supplied to the mine, and so reducing the investment in large heating or cooling systems, is to use rock as a thermal regenerator or thermal storage system. Packed rock beds act as thermal inertial units, damping the atmospheric temperature oscillations to provide a more constant fresh air temperature. However, although regenerators exist in some mines, and packed bed rocks have been studied in detail in solar thermal power applications, there is a lack of tools to design new and sufficiently large storage systems of this kind. This work fills the existing gap by presenting a methodology to design and evaluate the impact on the ventilation systems of these regenerators. The method is validated using existing rock bed systems found in the literature and illustrates possible designs for small and large size regenerators in both hot and cold climates.1 INTRODUCTION “ It is quite amazing how often answers to extremely complicated problems can be obtained in this way, by using greatly simplified models of the real situation for the purpose of calculation.” Whiller, A. in private communication to J. S. Stachulak (1989). Motivation Most underground mines located in regions with extreme climatic conditions require the thermal pre-treatment of the fresh ventilation airflows, whether for heating or cooling. Heating commonly is needed in sites with sub-zero temperatures and is usually effected by direct or indirect burning of natural gas or propane. Alternatively, cooling is required in areas with hot temperatures, or in mines with high underground thermal loads where the fresh air at ambient temperature cannot provide enough refrigeration. Thus, when the ambient air conditions cannot provide by itself enough thermal power to ensure safe underground working conditions, a heating or cooling plant is required, which involves a considerable equipment and operation cost."

Jan 1, 2019