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By Mostafa Benzaazoua, Emilie Ré, Raphaël Mermillod-Blondin, Hassan Bouzahzah, Jean-François Wilhelmy, University of Québec in Abitibi-Témiscamingue

"We analyzed two copper and lead flotation concentrates from the LaRonde mill using MLA technology (Mineral Liberation Analyzer) to identify the contaminants and to quantify their size and liberation. The MLA mineral quantification was compared with traditional mineralogical techniques (Scanning Electron Microscopy, Optical Microscopy, X-Ray Diffraction and Chemistry). The accuracy of MLA data was then quantify in application to metallurgical decision (mineral identification, mineral quantification, particle sizing and liberation quantification). We prepared five well-known materials from pure minerals and analysed them by MLA. MLA concentrates analyses showed the lead concentrate is mainly contaminated by pyrite and sphalerite. These minerals are liberated above 70 % and present a floatable size around 15 to 35 µm. Surface activation by dissolved lead from galena is therefore assumed for these contaminants. The analyses of the known samples show that mineral quantification and size distribution given by the MLA are consistent with the chemical analyses and the laser particle sizer. The liberation measurement is affected by the stereological effect. Modelling quantifies the overestimation of the particle liberation. Based on the modelling, the stereological shift on liberation should not impact metallurgical conclusions on the concentrate contaminations.INTRODUCTIONTo face the diversity of mineral processing challenges, the process mineralogy includes phase quantification, measurement of mineral size, liberation by exposure and by grade, association, surface contact proportion and texture. In the last decades, two SEM commercial tools emerged: MLA and QEMSCAN R. Both are based on specific combinations of backscattered electrons and X-ray images as well as image analysis routines developed at CANMET (Petruk & Pinard, 1976, Petruk, 1989), CSIRO (Frost, O'Hara, Suddaby, Grant, Reid, Wilson & Zuiderwyk, 1977, Reid, Gottlieb, MacDonald, & Miller, 1984) and JKMRC (Hall, 1977, Gu & Sugden, 1995). Recently, TIMA (TESCAN) and Mineralogic MiningR (ZEISS) supplied automated mineralogy for mining industry (Bouzahzah, Benzaazoua, Graham & Cropp, 2015, Gottlieb & Dosbaba, 2015a). In parallel, home-made routine were developped to resolve mineralogy challenges in mineral process but also in geometallurgy and mining environment (Kahn, Mano, & Tassinari, 2002, Knight, Klassen & Hunt, 2002, Mermillod-Blondin, Benzaazoua, Kongolo, de Donato, Bussiere & Marion, 2011, Hunt & Bradshaw, 2015). SEM mineralogy become essential to operation by setting units on mine sites (MacDonald, Latti, Adair, Bradshaw, & Dunn, 2011, Goergen et al., 2013, Dobbe et al., 2014, Gottlieb & Dosbaba, 2015b)."

Jan 1, 2016

By S. Vongpaisal, T. R. Yu

"A set of new blast damage criteria has been developed, with special reference to blasthole mining operations, for assessing damage by incorporating the vibration level, rock properties, site characteristics and the effects of ground support systems. The main objective of this work was to provide a database with reasonable accuracy for use in optimizing blast design, numerical analysis and ground control expert system module development.The new damage criteria allow one to estimate the degree of damage to rock structures in terms of a dimensionless parameter defined as Blast Damage Index (BDI). This allows for the description of blast damage in a unified form, and facilitates the development of codes for numerical modelling to express the degree of blast damage universally. A number of field investigations from several stope production and slot opening blasts at a large underground base metal mine were carried out to verify the developed index. The results show a good correlation between the observed damage and the type of damage predicted from the BDI values.Practical measures are also provided for minimizing blast damage in large underground blasthole mining operations"

Jan 1, 1996

By John Convey

This paper, a follow-up to an earlier study, gives the history of Canadian developments in mineral processing from 1921 to the fall of 1964. It deals extensively with comminution and flotation, and then goes on to cover the fields of gravity concentration, magnetic concentration, cyanidation, the processing of uranium ores, and instrumentation. Several outstanding examples of installations are given. The paper concludes with a discussion of present-day trends in mineral processing. Introduction T HE history of the developments in mineral processing in Canada from its earliest times to 1920 has already been published by one of the authors (1). The present paper is thus a logical follow-up to bring this history to date. From 1834 to 1920, mineral processing in Canada, as elsewhere in the world, was in its formative stage. This, however, prepared the ground for developments that have resulted in a mining empire from the Atlantic to the Pacific, a mining empire which could be said to be almost on par with that in the United States.

Jan 1, 1965

By Neil Campbell

"The Pine Point area is on the south shore of Great Slave Lake, 510 air miles north of Edmonton and J JO miles south of Yellowknife, N.W.T. The occurrence there of lead and zinc was reported in J 899 by R. Bell (5) of the Geological Survey of Canada, and in the following years several claims were staked and some prospecting was done. In 1928 Atlas Exploration Co. took over the property containing the discovery occurrences. In 1929 The Consolidated Mining and Smelting Company of Canada Ltd. (""Cominco"") and Ventures Ltd. participated with Atlas in forming the Northern Lead-Zinc Co., which, under the direction of J. M. Bell, carried out 24,499 feet of drilling in the discovery and surrounding areas. Two shafts and many surface pits were also sunk. This work showed that the discovery deposits contain about 500,000 tons of lead-zinc ore, but no new orebody was found.In 1936 D. F. Kidd (11) drew attention to the highly significant space relations between the base-metal discoveries at Pine Point and the projections of certain major Precambrian faults mapped earlier by C. H. Stockwell. Geological work by Cominco in 1940 and subsequent years suggested the presence of mineable deposits within a belt of land including part of the area of earlier field work and extending far beyond it. Between 1946 and 1954 exploration financed by Cominco and Ventures Ltd. included 182,950 feet of diamond drilling, 383 feet of sinking, and 240 feet of drifting, raising, and crosscutting. This work was successful in finding substantial quantities of new ore in places where bedrock is completely concealed.The topography is one of low relief, characterized in many places by swampy muskeg and shallow, marl-bottomed ponds. The area where ore has been found is generally higher ground which, though not well drained, is comparatively dry. It is also marked by raised beaches and a few sand dunes overgrown by small spruce and pine. Bedrock is generally overlain by a variable thickness of hard, glacial boulder clay. This in turn is covered by silt, sand, and gravel, probably deposited from the waters of Great Slave Lake, which formerly extended many miles beyond its present southern shore."

Jan 1, 1949

By S. Averill, B. Schreiner, V. Sopuck

The La Ronge. Kisseynew, Glennie Lake and Flin Flon domains. the main focu for gold exploration in the southeast part of the Saskatchewan Shield, were subject to continental glacial ice advances from the northeast during the Quaternary. Based on forty-four auger hole along with surficial mapping, the general Quaternary stratigraphy in this area is observed to be composed of a lower till unit , an overlying stratified unit of glaciofluvial sand and gravel and/or a glaciolacustrine silt-clay unit. an upper till. and an upper tratified unit. The lower till is commonly found throughout the geological domains except where it has been eroded in glaciofluvial or fluvial channels. Glacial Lake Agassiz fo rmerly covered most of these prospective domains. The lacustrine deposits associated with the lake impede surficial geochemical surveys including soil. lake sediment. and biogeochemical surveys. The approximate extent of clay cover can be predicted from beach elevations. For instance. in the Waddy Lake area. clay i not known to occur above about 1,400 feet (425 m) elevation. Exploration techniques are hampered by clay in at least one third of the volcanic belt. Thi s influence is indicated by the fact that nearly all gold prospect found to date are located above 1,400 feet (425 m) while the area of clay cover is vi rtually unexplored. The upper till i related to a minor ice readvance. This till is the medium often sampled during soil surveys in the area . lts value as a geochemical ampling medium is dependent on the extent of erosional contact with bedrock highs on the lower till. Those areas which are relatively free of lacustrine and fluvial deposits are those where surface geochemical methods work best. In the Waddy Lake volcanic belt approximately 25-50% of the area may be suitable for surficial surveys. The area of the Star Lake prospect occurs above the 1,500 foot (460 m) elevation and was not covered by Lake Agas iz. The effectivene of till sampling as a surface sampling medium was tested in those areas above the clay level. Till orientat ion surveys were carried out at the Star Lake property and the Tower Lake prospect (Waddy Lake area) within the La Ronge Domain . Gold grain counts and analy es of heavy mineral concent rate from 7 kg surface ti ll samples were used to delineate dispersion trains down-ice from mineralization. In addition, the clay fraction and a 30 g (-80 mesh) subsample from the same till sample, were analyzed for gold . In the Star Lake area, ice direction is subparallel to the strike of several narrow northeast trending auriferous structures. arrow dispersion trains down-ice from known

Jan 1, 1986

By K. Muehlenbachs, J. U. Stemler

"Abstract - The Boston deposit is a recently discovered Archean lode-gold deposit located approximately 700 km northeast of Yellowknife, in the southern portion of the Hope Bay volcanic belt. Primary H2O-CO2-NaCl fluid inclusions associated with gold mineralization at Boston are of low salinity (4.6 ± 1.4 eq. wt.% NaCl, n = 182) and contain pure CO2. Homogenization temperatures of liquid-phase inclusions average 270° ± 33°C (n = 141), but some fluid inclusion assemblages contain coexisting liquid- and vapor-phase inclusions that homogenize near critical conditions, suggesting phase separation. In these groups, liquid-phase inclusions homogenized at 299° ± 25°C (n = 24), and vapor-phase inclusions homogenized at 338° ± 28°C (n = 18). These temperatures overlap within error, and a median temperature of ~320°C is taken as representative of trapping conditions within the veins. An approximate pressure of 2-3 kbar was estimated from fluid inclusion isochores at this temperature. Stable isotopic compositions of carbonate minerals from the mineralized zones range from -4.7‰ to -3.1‰ in d13C, and from 11.2‰ to 12.8‰ in d18O; quartz ranges from d18O = 12.8‰ to 14.9‰; and pyrite ranges from d34S = 2.1‰ to 3.5‰. The d18OH2O, d13CCO2, and d34SH2S values of the fluid calculated from these minerals at 320°C are 6‰-9‰, -2.4‰ ± 0.6‰, and 1.5‰ ± 0.5‰, respectively, and are intermediate between metamorphic and magmatic compositions. A unique source for the fluids cannot, therefore, be constrained from these data. Petrographic and geochemical data for the Boston deposit are consistent with data from other Archean lode-gold deposits worldwide, implying that the Boston deposit formed in a similar environment and from similar types of fluids. These results suggest that the Hope Bay volcanic belt may represent a major new mesothermal gold belt in this part of Nunavut. Sommaire - Le gîte Boston a été récemment découvert à environ 700 km au nord-est de Yellowknife dans la partie sud de la ceinture volcanique de Hope Bay, il s’agit d’un gîte d’or filonien d’âge Archéen. Les inclusions fluides primaires de H2O-CO2-NaCl associées à la minéralisation aurifère du gîte Boston présentent une faible salinité (4.6 ± 1.4 eq. pds.% NaCl, n = 182) et contiennent du CO2 pur. La température d’homogénéisation des inclusions à phase liquide est en moyenne de 270° ± 33°C (n = 141), mais certains assemblages d’inclusions contiennent des phases liquides et gazeuses coexistantes qui s’homogénéisent dans des conditions quasi critiques, suggérant qu’elles résultent d’une séparation de phase. Dans ces groupes, les inclusions de phase liquide s’homogénéisent à 299° ± 25°C (n = 24) et les inclusions de phase gazeuse s’homogénéisent à 338° ± 28°C (n = 18). Ces températures se recoupent à l’intérieur des limites de l'erreur de mesure, et nous considérons qu’une température médiane de ~320°C est représentative des conditions de piégeage dans ces veines. Les isochores permettent d’estimer une pression d’environ 2-3 kbar à cette température. La composition des isotopes stables des carbonates dans les zones minéralisées s’étend de -4.7‰ to -3.1‰ pour d13C et pour de 11.2‰ à 12.8‰ pour d18O; les valeurs de d18O pour le quartz varient de 12.8‰ à 14.9; et les valeurs de d34S dans la pyrite vont de 2.1‰ à 3.5‰. Les valeurs de d18OH2O, d13CCO2, et d34SH2S du fluide calculé à partir de ces minéraux à une température de 320°C est de 6-9‰, -2.4‰ ± 0.6‰, et 1.5‰ ± 0.5‰ respectivement, reflétant des conditions intermédiaires entre des compositions métamorphiques et magmatiques. Il n’est donc pas possible d’identifier une source unique pour ces fluides à partir de ces données. Les données pétrographiques et géochimiques du gîte Boston sont similaires à celles d’autres gîtes d’or filoniens ailleurs dans le monde, ce qui implique que le gîte Boston s’est formé dans un environnement similaire à partir des mêmes types de fluides. Ces résultats suggèrent que la ceinture volcanique de Hope"

Jan 1, 2006

By Jason Mewis

Do you have it figured out? ? If so, I want to network with you! ? There?s a lot to learn as an industry The more we share the better we?ll all become at dealing with this subject If you don?t have it figured out ? You?re among the majority in the in0dustry ? Project Risk is a broad and complex issue that is dealt with through many processes ? And it?s not intuitive either ? And you don?t want to confuse one process with Another

Nov 1, 2011

By Washington Luiz Mafra

Every year the conventional direct reduction processes ? Midrex and HYL III ? increased their market share in the world steel production, even though they are only economically feasible in countries where natural gas is available at competitive prices. In this context, the new Midrex projects are based on large reactors (Megamod - 1.5 to 1.8 Mt/y of DRI), reduction temperatures of the metallic burden up to 850oC, with bustle gas temperatures between 960oC e 1050oC. Thus, the requirements of metallic burden performance, as well as the evaluating methods, usually based on ISO standards, need to be reviewed. It is well known that the standards usually applied to quality evaluation do not reflect the performance of metallic burden inside the reactors. This paper describes the different methods of evaluating the disintegration under reduction of DR pellets based on ISO 11257 standard. This is the most important method used by pellet producers and customers for evaluating DR feedstocks. The different methodologies tested to evaluate the disintegration under reduction had varying results, evidencing the relevance of the method and the quality of the pellet. Nevertheless, validating the method in an industrial reactor is still fundamental.

May 1, 2007

By G. A. Vissac

METHODS of coal preparation have been greatly developed and improved during the past few years. Under the pressing competition from substitutes that have been displacing coal as a source of heat or power, the coal industry has been able, in many cases, not only to hold its own but to regain much of the lost ground, by offering better products of a higher value. The purpose of this paper is to present, in a brief and simple form, the principles of the latest methods and machinery used in coal preparation, in order to enable the coal operator t0 select methods and equipment capable of solving his own problems in the most efficient and economical way. The paper will deal, in the main, .with coal cleaning. It must be emphasized, however, that a complete coal preparation study covers many other operations, such as handling, screening, de-dusting, dust-proofing, and ash-conditioning. Handling Coal From the producing face to the railway car, coal must be handled with great care, t0 prevent degradation, because the coarser sizes are not only easier to clean than fines but, for our markets, they are often the more valuable. Generally speaking, such care is less important or is unnecessary in the Old Country, where conditions are different. The best way to minimize breakage is to avoid gravity methods in coal transportation. All chutes in a preparation plant should be shaken mechanically, and cleaning processes requiring large surge bins must be avoided. De-Dusting De-dusting of coal is accomplished by the use of vibrating screens, fans, or classifiers, or by a combination of these. Fines below 1/32-in. (or coarser than this, with some coals) can very seldom be cleaned efficiently. Common practice is to discard them immediately, if the moisture content of the coal allows this to be done. Otherwise, they are liable to give unnecessary trouble, either in the form of dust or sludge, which are difficult to collect or to settle. Flotation is the only process which will effectively clean fines.

Jan 1, 1937

By Rowena Anderson

Mining companies are now looking for more effective ways to engage the community in public participation. Consensus-based approaches are becoming the most popularly applied way of achieving meaningful public participation. This paper introduces the principles surrounding consensus-building approaches and the processes for getting them started. The Healthy Communities Movement is one such consensus-based approach that offers a well-established holistic model for conceptualizing a healthy sustainable community. It also highlights the importance of public participation as an essential component of achieving a sustainable community. The paper concludes by illustrating how current company-community relations programs can utilize these models.

May 1, 2002

By Robert Hamilton

Aur Resources is Canada's leading copper mining company with producing mines and development projects in North, Central, and South America. Copper production from Louvicourt Mine in Quebec, Quebrada Blanca, and Andacollo Mines in Chile had a record of 245 million pounds in 2001. Located 600 km North of Montreal, Louvicourt Mine is a joint venture between Aur Resources (30%), Teck Cominco (45%), and Novicourt (45%). Aur Resources is the mine operator with 280 employees working to produce a copper and zinc concentrate. In operation since 1994, the mine has produced a total of 12,606,000 metric tonnes of ore grading 3.6 % Cu, 1.5 % Zn, 26gr./m.t Ag, 0.9gr.m.t Au. This highly mechanized mine reached full production in August 1995 at 4,000 tpd. From 1996 to 2001, the average mine production rate was more than 4,300 tpd. The Louvicourt Mine continued its record of solid performance in 2002 and is expected to continue to do so for the balance of its 2.5 years mine life.

May 1, 2003

By D. R. Keck

"SINCE the .Canadian Chemical Company has no direct connection with mining operations, and I have had no experience with mining, there is little I can tell you that you do not already know. However, we have had considerable experience with certain types of metallurgical problems and I would like to discuss with you some of these problems and their solutions by our metallurgists.In order to acquaint you with the type of plant and processes to be employed at Edmonton, I would like first to take a few .minutes to trace briefly the history -of the Canadian Chemical Company's affiliate, The Celanese Corporation of America. In the early •part of the twentieth century, two young Swiss brothers, Camille and Henri Dreyfus, received their P.h.D. degrees in chemistry. They were extremely interested in work which was being carried on at that time to find a suitable synthetic fiber that could compete with natural fibers, both quality and price-wise. Early man-made fibers were both coarse and hard to dye. The Doctors Dreyfus• poured all their earnings into research and ultimately developed cellulose acetate filament. During World War I, the Dreyfus brothers were invited to the United States to produce cellulose acetate 'dope' for airplane wing coverings. Dr. Camille Dreyfus built the first American plant for fiber production at Cumberland, Maryland, in 1924.Due to resistance of textile mills to the new fibers, Celanese was forced to set up its own dying, weaving, and finishing mills to prove the new materials. Through the years, however, this operation has •been retained primarily for fabric development purposes,.. with the majority of the acetate being sold to other textile mills."

Jan 1, 1953

By E. A. Rychkun

"For the last 700years of recorded economic history, man has been subjected to alternating inflationary and deflationary patterns. Through this period of time, a severe deflationary pattern has developed approximately every 55 years, creating 12recordable occurrences. Through the last two centuries, this severe deflationary phenomenon has come to be known as a depression. As these depressions have repeated themselves regularly, they are cyclic. This in turn leads to the question of whether the 13th cycle will also repeat itself in the form of a depression. As this cycle is now 51 years old, we must consider the possibility at about 1984.In analyzing a 700-year record of consumer prices in Southern England, the 55-year cycle appears to vary in shape and intensity. This varying phenomenon is due to the effect of longer cycles upon which each one ""rides "". Because each cycle effectively rides on the next largest, which in turn rides on the next largest and so on, the combined measured effect of all cycles together at any point in time is always unique. This means that anyone cycle can never repeat itself in an exact identical manner. The combined effect therefore is what we observe in the form of prices and, as cycles interact, variations in deflation are produced . The ""science"" of economics attempts to quantify and develop theory on situations which are never identical and hence can be conservatively classified as a useless predictive tool.This means that more unconventional approaches may be required to predict our economic future. In looking at previous depression cycles, it is possible to recognize similarities in human behaviour patterns and hence the resulting economic movements. These behaviour patterns create major events or influencing factors which set the scene for a major deflationary condition. The way in which these factors occur, however, is not predictable. As more and more of these similar events are identified in each cycle, we can increase our confidence on the probability of the last event occurring (a depression). By also unravelling the set of larger cycles, we can determine the potential combined effect at any point in the future.This paper presents a system of cycles ranging from 800 years to 3 years which appear to operate in our economic system. By so doing, a long-term projection into the next century can be made. Finally, the paper deals with the main controlling similarities within the depression cycle, to show that a comparison with our current cycle implies that a major deflationary collapse in the mid 1980's is virtualy inevitable."

Jan 1, 1980

By Pura Alfonso, Teresa Escobet, Hernan Anticoi, Eduard Guasch, Josep Oliva, Sarbast A. Hamid

"The liberation modelling of mineral particles using mineral liberation analysis have been used in the past to model comminution and concentration processes. In this work this concept has been taken a little further, using comminution and concentration for applying the mineralogical characteristics of particles. This approach is shown using the image analysis, mineral liberation analysis and the distribution density functions for liberation modelling. The work focused on the effect of comminution on mineral liberation for liberation modelling. To model this, effect the mineral liberation of the particles using distribution density and the cumulative distribution was linked to the image analysis of the ore particles. These properties have been estimated by statistical measures such as the distribution density and liberation grade, which were extracted from MLA data and images analysis, using proper image analysis and techniques based on MATLAB software. A comparison of different tungsten ores of liberated particles, has been introduced and evaluated by estimated results and image analysis.INTRODUCTION The chief economic minerals of tungsten are wolframite [(Fe,Mn) WO4] and scheelite(CaWO4), and approximately two-thirds of the world tungsten reserves consist of scheelite deposits (Lassner and Schubert, 1999). Tungsten has unique properties and is widely used in various industrial high strength and high temperature applications. It occurs coarsely aggregated in low grade ores. Most of tungsten ores, particularly scheelite, wolframite and ferberite, occur in deposits with very low content of WO3 (0.1–2.5%) that is not economically viable to apply directly metallurgical methods to extract tungsten (Martins, 2014). Tungsten is considered as a critical metal by the European Union by the economic importance and also the high supply risk (European Commission, 2014; Chakhmouradian et al., 2015).Currently, scheelite is playing an increasingly important role in tungsten industry because the mineral reserve of wolframite is getting depleted after gradual exploitation and utilization (Min et al., 2016). In mineral processing, the liberation of valuable mineral from the gangue determines the efficiency of subsequent separation processes. The liberation characteristics of an ore are primarily dependent on its texture, the association of mineral in the host matrix of gangue minerals, and to some extent on the grinding process (Zhang and Subasinghe; 2013)."

Jan 1, 2017

By G. P. Gu, B. Fang, R. W. Revie, M. Elboujdaini

Stress-corrosion cracking (SCC) tests were conducted in the near-neutral pH standard solution, NS4, and in an actual soil solution, using four-point bending at high a stress ratio and low frequency conditions very similar to those of operational pipelines. Pitting incubation appeared first and then pitting initiated and grew in both solutions although there were many more pits on the specimen tested in soil purged with 5% CO2 + 95% N2 than in the specimen tested in NS4 solution purged with the same gas. These observations show that samples in soil solution are more susceptible to pitting than those in NS4 solution. When the pit reached a critical size, the increased stress concentration around the pits, resulted in the transition to a crack.

Jan 1, 2005

By G. G. Bowser

THE time has come when, as your President, 1 turn the helm over to my worthy successor. When 1 was reminded by our Secretary that 1 had to prepare an address for this meeting, 1 was at a loss for a subject. In the hope of inspiration 1 perused the records of our Society for some years past. 1 found in these records that many problems in need of solution relative to industry in Nova Scotia were discursively dealt with and that sound thought was given to the solution of these problems, with a natural leaning, of course, to problems pertaining to the mining industry. 1 found also that some of the reasoning was remarkably prophetie. Some of these subjects and problems were: The use of pulverized coal to generate power instead of hydro-electric power; rural electrification; the importance of youth training for an efficient place in industry; the proper marketing of coal; the fuels competing with coal; the need for better in-dustrial relations between employer and employee; better education for success in the social field as applied to industry; and Canadian unity. The issue of some of these copies has been forced upon us by war. For instance, there appears to be no marketing problem for coal, nor does there ? seem to be a marketing problem for anything just at present. The problem of the coal producer just now is supply and transportation. Also, at present, coal fe.ars no competitors, such as oil-and not even hardwood. Many large companies now have an industrial Relations or Personnel Manager and department. Furthermore, we have been compelled of necessity to train our young men, and women also, for both industry and war. However, war does not solve these problems and, with the return to normal times, we may be faced with the same troubles in even greater measure. My reason for mentioning these copies is to point out that, as mining men, we are aU desirous of progress in every industry, not only the mining industry; and that mining men are able to see clearly ahead. In normal times, especially in matters not directly affecting the mining industry, we are inclined to let matters take their own good rime, or let the government do it. We do not seem to realize that these necessary and desirable changes can be made in times of peace-instead of being forced upon us by war or other social upheavals-by the method of sound thought and action to the desired end.

Jan 1, 1943

By Pizhi Zhao, Yingdong Li, Hailong Cao, Yingjuan Feng

"Three types of anodic films (unsealed, hot water sealed and agent sealed) were prepared to study the effects of anodizing pores structure on the adhesive bonding performance of AA5754 automotive sheets. The morphology of the anodic films was examined by using scanning electron microscope (SEM) and the composition was examined by glow discharge optical emission spectroscopy (GDOES). The adhesive bonding strength and durability in corrosive environment were investigated by using single lap shear test and salt spray corrosion test (SST), respectively. The results showed that the pores structure could significantly influence the adhesive bonding performance. The unsealed sample showed porous structure and provided high bonding strength, however, the durability was poor in corrosive environment. The hot water sealed sample showed fine and loose hydrated alumin a structure on the surface and provided high durability in corrosive environment, but the bonding strength was low. In contrast, the agent sealed sample provided both high bonding strength and durability in corrosive environment.INTRODUCTIONAdhesively bonded aluminum joints by using adhesives have been widely used for the realization of lightweight design in industrial applications like automotive and aerospace industry[1, 2]. Durable bonds which are capable of taking structural loads can be created due to a careful consideration of the way in which the joint is formed, the type of adhesive and the appropriate treatment of the adherend surfaces prior to bonding[3-6]. Experiences demonstrate that the surface treatment is the most critical step which could not be disregarded, since it is essential to achieve long-term service capability [7].In structural applications, a bonded assembly is expected to maintain a significant load and may be combined with exposure to harsh environmental conditions in its service life. For this purpose, the pretreatment for structural bonding of aluminum alloy must provide not only strong tensile strength and durability but also good corrosion resistance. Chromic acid anodizing (CAA) process provides an anodized layer which has good corrosion resistance while also exhibiting useful adhesion characteristics as well as lacquer coating retaining characteristics[8].However, the use of Cr (VI) is unadvised from a health and environmental point of view since it is toxic and carcinogenic, and this process is gradually limited even prohibited. Boeing's phosphoric acid anodizing(PAA) process provides a more open pore structure allowing penetration of high molecular primers/adhesives[8]and PAA process is the most widely used pre-surface treatment suitable for adhesive bonding between aluminum alloy components. Rahimi et al. demonstrated that nanostructure can be produced by PAA process and is affected by the time of pretreatment and anodizing parameters [9]. Xu et al.investigated the influence of surface energy and roughness on adhesive bonding through PAAprocess and provided improved adhesion performance under certain anodizing parameter[10]. However, PAA process is normally not recommended for a major concern of deterioration of the mechanical performance of the joints as a result of exposure to a wet and corrosive environment. Sulfuric acid anodizing(SAA)process, recently, has been widely used for corrosion protection and good base coating for the adhesion of lacquers in aerospace manufacturing[11]. The good performance is explained by properties such as the porous morphology and high adsorptive power of the oxide film, the chemical and electrical inertness of the anodized layer. Moreover, modified sulfuric acid could also used for adhesive bonding. Lunder et al. found that anodizing in hot sulfuric acid is promising as a simple, very rapid and environmentally friendly pre-treatment for adhesive bonding[12].Saeedikhani et al. studied the process of phosphoric/boric/sulfuric acids anodizing and found it was is a promising pre-treatment for adhesive bon"

Jan 1, 2018

By William Ferguson, Claude Deveau, Wade Hazel, Stephen R. Young, Allen Lussier, Robert Copeland

"LocationSometimes known as the Bernie Lake mine, the mine is located about 180 km east-northeast of Winnipeg on the northwestern shore of Bernie Lake, close to the Nopiming Provincial Park and the Manitoba-Ontario boundary. The mine is accessed from Lac du Bonnet which is linked to the provincial road system.Brief Description of OperationTantalum Mining Corporation of Canada Ltd. operates an underground mine employing ramp access, room and pillar mining, and shaft hoisting for the production of tantalum, lithium and cesium minerals. Daily campaigned crushing of the tantalum and lithium ores supply separate concentration circuits. Tantalum recovery employs conventional gravity equipment together with recently developed centrifugal concentration methods. All tantalum concentrates go to Cabot Performance Materials for the production of tantalum chemicals and metal. Lithium minerals are recovered using heavy medium separation and silicate flotation to produce spodumene and montebrasite/amblygonite concentrates. The lithium concentrates are shipped worldwide for use in ceramics, specialty glass and mold powders. Cesium processing involves the dry grinding of pollucite as feed stock for the recently built on-site chemical plant dedicated to tl1e production of cesium formate, a high-density drilling fluid for use in the oil industry."

Jan 1, 2000

By Delio J-J Tortosa, Fred F. Langford

"The Cenex orebody occurs at the intersection of northwest and northeast-trending fault zones that formed during post-Hudsonian uplift. The ore is localized in breccia zones, along faults, and in veins and adjacent wallrocks. The host rocks are Tazin quartzo-fe/dspathic mylonites and ultramylonites and chloritesericite- quartz-graphite-feldspar mylonite schist. The uraniumbearing minerals are finely disseminated pitchblende and uraniferous titanate.The earliest mineralization may have been associated with /ate-stage retrograde metamorphism in the mylonite schist. The main stages of mineralization were associated with brecciation, hematization, carbonatization, and chloritization of the mylonites and ultramylonites. Uranium mineralization was clearly much later than any igneous or metamorphic activity associated with the Hudsonian orogeny.Late post-orogenic uplift, erosion, and deposition of the Martin continental clastics in fault basins were coeval with uranium mineralization. The deposit is consistent with a meteoric-hydrologic system constituting a source for orebearing fluids, hence the close spatial relationship of the uranium deposits in the Beaverlodge area with the basal unconformity of the Martin Group."

Jan 1, 1986

By Peter Broad

"Extracting any metal, especially specialty metals and rare earth elements, requires an in-depth analysis of the costs and potential revenue as well as a due diligence study of other stakeholder interests. Rare earth projects are generally in the billion dollar US range or above, and thus failure to accurately predict any loss of revenue caused by impurities within the product or additional effluent treatment costs can destroy an otherwise viable study. Two prime sources of input impurity are considered: impurities in the material feed and from reagents. The effect of these impurities factor on both the product (in reduced revenue) and on residual “tailings” that may incur additional unforeseen costs.INTRODUCTION“Truth passes through three stages. First, it is ridiculed. Second, it is violently opposed. Third, it is accepted as being self-evident” – Arthur SchopenhauerThe era of unscoped, unbudgeted construction ended about 150 years ago. Today’s engineer must design with confidence; but do so amidst proprietary secrets and unfamiliar pollutants, which present a myriad of interesting challenges. Is it possible to build a viable rare earth plant to a realistic budget, without destroying that which we cherish? Some see this as contradictory but in reality it is the only viable option.WHEN GOOD PROJECTS FAILWithout rare earths the Copenhagen agreement might be null and void. Running a wind turbine with a 30 tonne conventional magnet requires some hefty engineering and prohibitive investment. Despite their ‘Green metal’ applications, production of rare earths have created environmental nightmares, as Folger stated in 2011 when visiting Baotou, or has Jaing Mainheng who has been quoted by Ambrose Evans-Pritchard 6 Jan 2013. This comment is not a criticism of China; the details are from a 2012 white paper published by the Chinese Government that initiated a $6 billion environmental clean-up. Nor is China unique; other plants have had problems as well. There were toxic leaks in the 1990s from Mountain Pass, and the Mitsubishi Bukit Merah Plant (built in Malaysia in 1958) required a $100 million clean-up."

Jan 1, 2016