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By D. Haraguchi, S. Izawa, C. Tokoro, S. Owada

"Arsenic is widely known as a toxic element for humans, animals and plants. Because of more stringent wastewater standards not only in Japan but also around the world, research for appropriate and efficient treatment method for arsenic is becoming increasingly important. Coprecipitation or adsorption process using ferrihydrite is widely implemented for dilute As(V) removal from wastewater. In this study, the sorption mechanism of dilute As(V) with ferrihydrite in coprecipitation or adsorption process was investigated. To accomplish this, we conducted batch experiments of coprecipitation or adsorption and compared these results for sorption isotherm and zeta potential. These experimental results showed that sorption mechanism in coprecipitation process depends on the initial As/Fe molar ratio; simple twodimensional adsorption onto the surface of ferrihydrite when the initial As/Fe molar ratio was < 0.4, and some three-dimensional uptake with ferrihydrite when it was = 0.4. We also evaluated the sorption mechanim by analysis of X-ray diffraction (XRD) and X-ray Absorption Fine Structure (XAFS). XRD or XAFS spectra showed that surface precipitation of amorphous ferric arsenate was formed when the initial as/Fe molar ratio was = 0.4, beyond the thermodynamic bulk precipitation range for ferric arsenate.INTRODUCTIONArsenic is toxic to animals, including humans, and long-term exposure to arsenic via drinkingwater causes cancer of the skin, lungs, urinary bladder, and kidneys, as well as other effects on the skin such as changes in pigmentation and thickening (Ghosha et al., 2008). Elevated levels of arsenic are often present in the environment as a result of the weathering and dissolution of minerals as well as in response to numerous anthropogenic sources including the discharge of mine wastes, coal fly ash and the use of pesticides that contain arsenic (Nriagu, 1994; Singh et al., 2007). Indeed, the potential for arsenic exposure affects many people, as evidenced by several million people in Bangladesh and India being at risk of exposure via drinking water obtained from contaminated groundwater sources (Ahmed, 2001).Acid mine drainage (AMD) containing arsenic is a global environmental problem (Dold, 2008; Liang and Thomson, 2008) that also affects Japan, which has many abandoned or closed mines that have been generating AMD for the last few decades (Masuda et al., 2008). Several such facilities in Japan produce AMD containing dilute concentrations of arsenic that exceed Japanese effluent standards (0.1 mg/dm3) (METI, 2006). For example, AMD from the abandoned Horobetsu sulfur mine, the largest AMD source in Japan, contains approximately 10 mg/dm3 arsenic."

Jan 1, 2012

By Peter N. Calder

The orientation of planes of inherent weakness (joints) with reference to an excavation in rock is the critical factor determining stability. The purely frictional 'residual' strength remaining following the breakdown of initial cohesion is the only strength which can be counted on to resist sliding for the long term. A simple method of resolving driving and resisting forces in three dimensions along joint intersections 'undercut' by the excavation is presented. Contrary to the case of slope failure in soils, it is shown how significant changes in the slope angle sometimes have no effect on the degree of stability pre-sent in rock slopes. Wall control by reorientation of the slope, the use of cable bolts and water diversion are briefly discussed.

Jan 1, 1970

By A. E. Flynn

Introduction The purpose of this paper is to record the results of researches on anhydrite that have been undertaken at the Nova Scotia Technical College during the last two or three years. The work was carried out in the Mining Department of the College, and several investigators were engaged on the work from time to time. Messrs. R. E. Hanson and K. M. Ed devoted their mining theses to the investigation, and Messrs. J. C. Hall and G. W. Baker were engaged on the work during the summers of 1928 and 1929, respectively. The writer was responsible for the initiation and direction of these researches, which were made possible by the financial assistance of the Department of Mines of the Province of Nova Scotia. Nova Scotia is the leading Province in Canada for gypsum production, its output being about a million tons per year, or over 80 percent of the production for the whole of Canada. The commanding position of Nova Scotia in this regard is due to the abundant supply of gypsum and its proximity to areas of intense utilization in the eastern United States. The resources of gypsum are contained in a total area of 627 square miles of gypsiferous rocks, so that an enormous reserve of this mineral is available. Present operations are confined to the highest grade and most easily worked deposits close to water transportation.

Jan 1, 1930

By R. A. Rabnett, G. Paget, Patrick Walsh

"Tumbler Ridge, Canada&apos;s newest resource community, has been developed differently than have been other resource communities.Since its conceptualization, emphasis has been placed on the establishment of a traditional municipal government at early a stage as possible.Planning f or the community goes back to 1977. By then, extensive study by provincial agencies had shown a new resource town would be required to exploit north east coal. The Ministry of Municipal Affairs, in conjunction with a consultant named R.A. Rabnett began the extensive Tumbler Ridge conceptual plan.The results of the conceptual plan are evident in the organizational and planning goals of Tumbler Ridge. In every aspect from the election of officials to some financial matters, the town functions as a normal municipality. With the resource companies of the North East Coal Development within its municipal boundaries. Tumbler Ridge has been able to debenture its capital projects against its municipal tax base.The town&apos;s ability to function as a normal municipality is enhanced by its control over Crown land it has purchased from the province. This gives it further control over the development of the community and helps in establishing agreements with the resource companies and the provincial government to ensure that housing and service needs are met. While resource company representatives sit on certain municipal committees, their roles are advisory in nature.The community continues to move toward full municipal status and will have a fully elected Council by 1986.BackgroundPlanning for the development of northeast British Columbia coal resources began in 1976 under the aegis of the provincial Cabinet Committee on Coal Development. A series of subcommittees were established including a Townsite/Community Development subcommittee. The Ministry of Municipal Affairs chaired this subcommittee and continued as the lead agency for the provincial settlement planning effort over the period 1976 to 1981."

Jan 1, 1983

By H. Watari

In 1998, a voluntary agreement was reached between the European Commission and the European Car Manufacturers Association (ACEA) to reduce average carbon dioxide emissions of new cars to 25% below 1995 levels by 2008, Agreements have also been reached between the European Commission and the Japanese Automobile Manufacturers Association (JAMA) and the Korean Automobile Manufacturers Association (KAMA), However, the target average of carbon dioxide emissions of less than 140g/km in 2008 is a very challenging goal, Therefore, total product weight reduction is an objective for many manufacturers, This can be achieved utilizing materials possessing high strength and low weight, One material that has recently attracted interest is magnesium alloys, The magnesium alloys are expected to play an important role as next-generation materials, which have possibilities of contributing to lighten the total product weight when magnesium products can be used to replace aluminum and mild steel products.

Jan 1, 2005

By W. G. Worcester

THE chief object in presenting this paper on bentonite is to attract general attention to one of the least known and most neglected industrial minerals of Canada, a mineral of extensive commercial possibilities, as evidenced by its development and exploitation in other countries, principally in the United States and Germany; countries upon which some of our most important Canadian industries are dependent for their supply of special clays, such as Fuller&apos;s earth and activated bentonite. It was in view of these conditions and the knowledge of the presence of large quantities of bentonite in the Canadian West that the work here reported on was under-taken. While the investigational studies have not been completed, the results indicate that among the many samples tested there are some of real merit and industrial importance. While it has been the author&apos;s privilege to examine deposits and samples of bentonite from all of the Western provinces, his chief activities in the field and in research studies have naturally been confined largely to Saskatchewan materials. Notwithstanding this, however, this paper is presented in the hope that it may stimulate a more general interest in, and study of, Canadian bentonites as a whole, a matter of such importance that provincial boundary lines should be overlooked. GENERAL CHARACTERISTICS OF BENTONITE According to Schurecht and Donda (1), bentonite is commonly composed of the mineral montmorillonite, (Mg,Ca)O.Al203 5SiO2 .nH2O, though some are known to consist of beidellite, Al2O3 3SiO2.nH2O: where n is approximately 4, and in certain cases the Al2O3 may in part be replaced by Fe2O3. For present purposes, however, it may be sufficient to state that, in general, bentonite is a "soapy&apos; clay-like mineral or group of minerals composed largely of hydrous aluminium silicate, but frequently carrying small percentages of the alkalies, alkaline earths, and free silica, as well as silicates, gypsum, and other admixed detritus such that purification is usually necessary.

Jan 1, 1937

By D. F. VanDine

The phases of a typical exploration program for sand and gravel resources include: (1) collection and assessment of existing information; (2) air photo interpretation and remote sensing; (3) ground investigation and mapping; (4) sampling and testing; and (5) data storage, retrieval, analysis and presentation. Depending on the purpose, time frame and funding available for the study, these phases, and the various techniques used within each phase, will vary. Once a sand and gravel deposit has been located, defined in size and quality, and found to be suitable for a given purpose, it can then be classified as a granular resource.

Jan 1, 1984

By F. Chiesa, Jeremy Carignan, B. Duchesne, D. Levasseur

"Aluminium A206 (AlCu4) is one of the strongest aluminium casting alloys with tensile properties approaching those of ferritic ductile iron. If the specification on the silicon content (< 0.05%) is easy to achieve during alloy ingot production, it is not the case in a foundry, where returns are used which are not perfectly cleaned from the silicate containing molding sand (Olivine). In alloy A206, the Si content is controlled in order to avoid the formation of a low melting point intermetallic phase (such as phase Q Al5Cu2Si6Mg2); these phases will melt during the solutionizing heat treatment to which alloy A206 must be subjected to develop its outstanding mechanical properties. This incipient melting may deteriorate the mechanical properties of Alloy A206 if the solutionizing treatment is applied at the standard temperature of 530°C.In the present study, a lower temperature solutionizing (520°C) was applied to a high Si content 206 alloy in order to reduce or eliminate the possible incipient melting. This was carried out on a complex shape industrial casting weighing 14 kg (31 lb) and 560x410x250 mm (22x16x10”) in size poured in aluminum 206 with a high silicon content (0.22% vs 0.05% max for alloy A206). Twenty ASTM E8 subsize tensile specimens were excised from two locations in the casting in order to compare the tensile properties for the two solutionizing temperature used (530 and 520°C). Optical and SEM microscopy allowed to investigate the causes of the differences in the properties observed between the 2 zones of the casting studied for 3 different heat treatments. INTRODUCTIONIn spite of their “textbook” outstanding mechanical properties (Up to twice the strength and elongation of the widely used A356 alloy), aluminum-copper alloys of the 2xx series are seldom used because of their propensity for hot tearing [Li, 2011], the segregation of copper [Cho, 2003], and their sensitivity to stress corrosion cracking [Jean, 2009, p. 113)]. Also, because of their wide freezing range and high thermal conductivity, a wide mushy zone makes feeding difficult, unless strong temperature gradients are created by liberal use of chills and risers in the critical zones of the part. Because they are prone to hot tearing, grain refining of Al-Cu alloys is particularly important, titanium playing a major role in the process [Sigworth, 2003]; grain refining has also been shown to be beneficial to fatigue strength [Jean, 2009, p. 103]. The practical basis of foundry practices pertaining to these alloys is outlined in an AFS webinar [Weiss, 2014]."

Jan 1, 2016

By Peter C. Jones, Wanda M. Carter, David H. Watkinson

"Abstract - Pyrrhotite, chalcopyrite, and pentlandite are the dominant sulfide minerals in the 740 zone of the Kelly Lake orebody (Inco Ltd.), Copper Cliff Offset, Sudbury. Petrographic and quantitative electron microprobe analyses of minerals, from sulfide assemblages and host quartz diorite, of the 740 deposit have revealed three processes that have affected sulfide mineralization and associated sulfarsenide and platinum-group-mineral (PGM) distribution: magmatic, hydrothermal, and tectonic. Accessory, zoned cobaltite, and gersdorffite occur in sulfides as a result of these three processes, and PGM occur dominantly in hydrothermally remobilized and deformed ores. Where PGM are present in sulfarsenides they provided nuclei for sulfarsenide growth. Solitary PGM are orders of magnitude larger than those PGM found within sulfarsenide minerals. Five varieties of PGM occur, michenerite and sperrylite being the most common, with lesser froodite, hollingworthite, and ruarsite.The effect of a deformation is a localized fabric in the ore, revealed by pyrrhotite and chalcopyrite bands; pentlandite porphyroblasts also partially define the foliation. The deformed ore is also characterized by alteration of the adjacent quartz diorite, which produced an alteration assemblage including almandine garnet, Fe-rich biotite, and chlorite."

Jan 1, 2001

By P. L. Claessens, S. Belisle, C. Bowen

"Use of zinc shot feed is a well-established procedure among North American electro-galvanizers. This form of zinc is easy to handle and relatively inexpensive when compared with zinc oxide. This paper reports results on the kinetics of zinc shot dissolution in traditional pure zinc solutions and in electrolytes used for the plating of nickel/zinc alloys. Despite the cementation of minor amounts of nickel in the latter solution, acceptable dissolution rates of the zinc shot can be achieved through proper adjustment of the solution velocity. Under these conditions, the nickel shell produced by cementation is continuously abraded, exposing the underlying zinc.IntroductionThe use of insoluble, noble metal-containing anodes rather than soluble zinc anodes for the operation of high current density electro-galvanizing lines has gained almost universal acceptance. Two major reasons for this trend are:• improved control of the process by virtue of constant inter-electrode distance; and• increased productivity because the operation of the lines does not require the relatively frequent interruptions for replacement of consumed anodes .The results of the principal anode and cathode reactions are, respectively, depletion of the zinc content of the electrolyte and the increase on its acidity;"

Jan 1, 1991

By F. Azgomi

A possible way to characterize (classify) frothers using gas holdup as a surrogate for bubble size was explored. Nine surfactants with a range in chemical structures were selected and tested in a bubble column instrumented to measure gas holdup and superficial gas velocity. A correlation between frother type and gas holdup was observed: for alcohols, gas holdup increases with hydrocarbon chain length and the effect is the same whether the chain is branched or straight; for polyglycols, gas holdup increased with number of propoxy groups. The ranking by gas holdup gave the same result as other frother characterization techniques.

Jan 1, 2006

By M. E. Holter

"Five main lignite seams occur in the Tertiary Ravenscrag Formation in the Eastevan area, at depths of 100 feet or less. They are named, in ascending order: the Boundary, Estevan, Souris, Roche Percee and Short Creek seams. A total sequence of approximately 250 feet is represented by the coal beds and interstratified clays, silts and sands. Strata dip to the southeast at 25 feet per mile or less and trike northeast. Large areas underlain by coal seams at shallow depths are delineated. Reserve calculations are dependent on detailed information on seam thicknesses and feasible stripmining depths. The stratigraphically higher seams are thinner on the average than lower seams and this, together with the increase in elastic size fractions in higher strata, suggests a retreat of a Tertiary marine margin to the south during the closing depositional history of coal seams and associated strata."

Jan 1, 1972

Applying DEM to prediction of tumbling mill performance is challenging because several different modes of breakage are active in the process. As our knowledge of breakage and computational capacity improve, it is worth revisiting previous simulation tasks which did not produce a satisfactorily realistic description of a measured process. At SAG 2006, we reported the simulated and measured outcomes of treating a well characterised ore in a 1.2 m diameter mill. This well instrumented, pilot scale mill at the University of KwaZulu-Natal has been combined with some new approaches to ore testing to allow different modes of breakage to be tested. The mill design allows the rate of generation of fine material to be measured in close to real time for autogenous and SAG mill charges. The updated simulation model estimates mass loss with particle evolution and embeds the cumulative damage and breakage. The simulated results are compared with the measured results. Issues such as relating modelling inputs to particle breakage characterisation data and the accuracy of the predictions of the models are discussed.

Jan 1, 2012

By Kevin Bell

About Beltek Inc. For more than a decade Beltek, Inc. has been working with national and international organizations to harness and deliver solutions which gain real ebusiness advantages in today&apos;s world. Our objectives are to partner with our customers to achieve maximum results, while reducing costs. At Beltek, we provide a commitment to you and your organization&apos;s needs. Whether that be delivered by ensuring our services and products are state of the art or by providing a level of personalized service, which makes you feel like the center of attention, Beltek is about adding value to every job we work on. The individuals who work at Beltek quickly become your friends because we share your passion and enthusiasm for the business we are in. That&apos;s why every person is a leader in his or her respective fields. Having these individuals as apart of our business ensures you get the best out of our equipment, receive the very latest in advise, problem solving and support. We also pride ourselves on our ability to remain flexible at all times because we know deadlines and schedules can change quickly, so we always go the extra mile to deliver exactly what you need.

May 1, 2004

By A. C. A. Howe, J. C. Rowntree

"The Bernie Lake pegmatite near Lac Du Bonnet in southern Manitoba is a complexly zoned pegmatite containing several lithium-bearing units in addition to the western world's largest known reserve of cesium. The pegmatite forms a flat-lying ellipsoidal body within an east-west-trending Precambrian amphibolite. The pegmatite enclosed by this vertically schistose amphibolite lies near the eastern tip of a granitic intrusive. The relationship of this intrusive to the pegmatite is obscured by Bernie lake. To date, the pegmatite body has been delineated aver an area of approximately 80 acres; it attains a maximum thickness of 280 feet. Several distinct zones, including three assemblages of economic importance, comprise the pegmatite itself. The combined spodumene and lepidolite assemblages provide a recoverable defined lithium ore reserve of almost 5 million tons averaging more than 2 per cent lithium oxide. The recoverable cesium ore of the pollucite assemblage provides 300,000 tons averaging more than 20 per cent cesium oxide; this represents more than half of the western world's pollucite reserve. The Bernie Lake pegmatite deposit, owned by Chemalloy Minerals Limited, is well located with respect to the growing United States markets, and its reserves of cesium are large enough to enable it, under favourable economic circumstances, to become the major producer of this metal in North America."

Jan 1, 1967

By M. Maleki-Moghaddam

At the concentration plant of the Gol-E-Gohar Iron Ore Company (Iran) three 9 m × 2.05 m AG mills (fixed speed) are used in parallel in a dry operation. The performance of AG mills has been lower than the target value indicated by an increase in the product size (P80) from 450 µm (target) to 515 µm and low power draw (50% of nominal). By simulation it was found that increasing the liner lifter face angle from 7 to 30o while keeping the original lifter height (i.e., 22.5 cm) could provide an appropriate charge trajectory. When the proposed liners installed in one of the AG mills, the throughput increased by 27%; when 5% (v/v) balls were added the throughput increased by 40%. The product size also decreased from 515 to 501 µm.

Jan 1, 2012

By François Robert, Rex Brommecker, Don S. Bubar

"The Orenada Zone 4 deposit is a small vein-type gold deposit occurring directly within the Cadillac Break southeast of Val d' Or in southeastern Abitibi Sub province. Mineralization is hosted by the Piche Group which, on the Orenada property, consists of talcchlorite- carbonate, chlorite-carbonate, and sericite-chlorite schists, derived from ultramafic volcanic, mafic igneous, and intermediate to felsic volcaniclastic rocks, respectively. All these rocks have been carbonatized.Rocks of the Pichi Group display a strong east-west, subvertical S1foliation, which is superimposed by asymmetric, intrafolial F2folds with shallow to moderate plunge to the east and to the west. F2folds are accompanied by an S2, subvertical axial planar cleavage, and are interpreted to result from dextral transcurrent shearing along sr.The Zone 4 deposit occurs within a large F2 fold, 60 m wide and plunging at 45 to the east, down to a depth of at least 300m. The auriferous zones consist essentially of zones of closely spaced, parallel quartz-tourmaline-albite-carbonate-arsenopyrite veins concordant to Sr these veins have been folded by the large F2fold and may pre-date the folding. A few discordant quartz-tourmaline-arsenopyrite veins, post- dating the F2 folding, also contain gold. Wallrocks adjacent to concordant veins have been carbonatized, albitized and contain significant amounts of tourmaline and arsenopyrite, with which gold is intimately associated.The Orenada Zone 4 deposit is a unique example of a deformed vein- type gold deposit, and exemplifies one of several types of association of lode gold deposits with folds."

Jan 1, 1990

By J. E. Dutrizac

The dissolution of low-iron sphalerite, (Zn,Fe)S containing 0.08% Fe, in ferric sulphate-sulphuric acid media was investigated using closely sized fractions of crushed sphalerite crystals and sintered disks made from the crushed crystals. Linear kinetics are observed, and the predominant reaction products are ZnSO4, FeSO4 and elemental sulphur. The leaching rate increases systematically with increasing temperature, and the calculated apparent activation energy is 56 kJ/mol for the sized sphalerite and 54 kJ/mol for the sintered disks. The relatively high apparent activation energy suggests that the rate is chemically controlled, a conclusion supported by the insensitivity of the rate to the disk rotation speed. The rate increases as the 0.22 power of the Fe(SO4)1.5 concentration, and as the 0.22 power of the H2SO4 concentration. However, in the absence of ferric ions, the rate increases more significantly with increasing H2SO4 concentrations, and relatively rapid rates are observed in solutions containing >0.5 M H2SO4. In 0.1 M Fe(SO4)1.5-0.3 M H2SO4 media, the measured rate decreases with increasing sulphate concentrations, added as Li2SO4. The rate of dissolution of low-iron sphalerite is promoted by dissolved copper concentrations as high as 800 mg/L. In contrast, dissolved silver, even in the 0-2 mg/L concentration range, significantly retards the dissolution of the low-iron sphalerite.

Jan 1, 2008

By A. Koning, P. Lauzon

Pressure hydrometallurgy operations require vessels to be lined with an impermeable membrane for corrosion protection and one or more courses of refractory or ceramic brick. Examples of unit operations that utilize composite lining systems include pressure oxidation autoclaves, sulphide precipitation autoclaves, chloride leach reactors, flash vessels, cyclone separators, and direct contact condensers (heater vessels and quench vessels). The refractory lining must satisfy multiple requirements: it must thermally insulate the membrane from process fluid, be structurally stable, provide erosion resistance, be chemically compatible with process fluid, and provide an economic service life. New hydrometallurgical processes are pushing the pressure, and temperature, with each new generation of plants. A fundamental understanding of all factors affecting the mechanical stability of the lining system is essential as lining designs move further away from the industry&apos;s experience base. The impact of irreversible chemical swell, operating factors, design factors, and installation factors are presented based on modifications to the traditional one-dimensional mechanical stress model. A new stability criterion - that the brick lining remain in contact with the steel shell membrane - is presented. This new stability criterion imposes new restrictions on the lining design.The effect of geometry and adding additional degrees of freedom to the analysis is explored using two-dimensional and three-dimensional Finite Element Analysis (FEA). The effect of these additional degrees of freedom on the results of the one-dimensional model are discussed.

Jan 1, 2004

By L. Haavanlammi

Iron is a significant component of all copper concentrates leached in the HydroCopperTM process. The metals in the concentrate are leached in a chloride solution by oxidation with cupric ions. Copper enters into the solution as a cuprous chloro¬complex. Iron dissolves at the same time in the ferrous form, but it is immediately oxidized to the ferric state. Oxidation is effected by sparging air or oxygen into the leaching reactors. Because the pH is 1 - 2.5, ferric ion precipitates as akaganeite (T<90°C) or hematite (T> 90°C). Arsenic, antimony and the main part of the bismuth co-precipitate with iron and report to the leach residue. Cupric leaching is faster than iron oxidation; thus, leaching of low-iron concentrates (secondary copper minerals) is quicker than leaching high iron concentrates (chalcopyrite). Pyrite does not dissolve during copper leaching, but is oxidized slowly at higher redox-potentials after the copper has been leached.

Jan 1, 2006