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By Davood Moradkhani, Maryam Rasouli

"The present study reports solvent extraction and separation of zinc from concentrated nickel sulfate solution. In our previous study, Zn and Cd in cold filter cake (CFC, 45-55% Zn, 11-16% Cd, and 2.5-4% Ni) were extracted by alkaline leaching followed by electrowinning processes respectively. The strip solution from electrowinning process, was a pregnant liquor solution (PLS) containing 16.8 g/l Ni and 4.2 g/l Zn. In this work, PLS is subjected to the solvent extraction process for separation of traces of Zn from high grade nickel. The zinc free raffinate containing 16.6 g/l Ni sulfate solution will flow to nickel electrowinning plant for cathode production. Di-(2-ethylhexyl) phosphoric acid (D2EHPA) is the organic phase used in this study. The effects of various parameters such as organic phase concentration (10- 40 % v/v), pH (1.5-3), and temperature (25 and 45°) are investigated. Zinc over nickel separation factor increases by increasing pH from1.5 to 3. The results show that 98.7% of Zn was loaded at25°C O/A ratio of 1, pH 3, and 10% vol. D2EHPA. A 10 M NaOH is used for pH control. However, replacement of pH controlling agent with ammonia solution (25%. v/v) results in interesting observations. Ammonia addition, reduces the solubility of Ni2+ cations in solution. Nickel starts to precipitate from raffinate in a crystalline bluish-green form. The obtained crystals are characterized by XRF and identified to be nickel-bearing analog of boussingaultite, a rare sulfate mineral of nickel with chemical formula of Ni (NH4)2(SO4)2.6H2O. The crystallization rate of crystals is studied. It is a slow precipitation process with 75% in 4 days.INTRODUCTION Annually, many hydrometallurgical processes such as electrowinning, solvent extraction and leaching are applied to waste filter cakes in Zanjan, Iran. These additional processes on filter cakes are critical from both environmental and economic points of view. CFC (cold filter cake) is a toxic but valuable filter cake (45-55% Zn, 11-16% Cd, 2.5-4% Ni, and 0.2-1.5% Cu) produced in many zinc production plants. Our research group at Research and Engineering Company for Non-ferrous Metals (ReCo.), developed a series of hydrometallurgical methods for extraction of zinc, cadmium and nickel from CFC (Moradkhani, & Rasouli 2012). The recovery of zinc and cadmium with alkaline leaching and electrowinning was successfully studied. The strip sulfate solution from cadmium electrowinning unit, contains high concentration of nickel with some traces of zinc impurity. This pregnant liquor solution (PLS) was analyzed and reported to contain 16.8 g/l Ni and 4.2 g/l Zn. In this work, PLS is subjected to the solvent extraction process to separate Zn from nickel (Fig. 1). The organic phase stripping solution containing 4.2 g/l zinc and 200 ppm nickel can be circulated and used in the acidic leaching step. This generates nickel solution with high purity suitable for nickel cathode production."

Jan 1, 2017

By David Thomas, Charles Harper, Brian Watters

The Star-Waddy Lakes area lies withjn the northeasterly-trending early- to mjd-Proterozoic volcanoseilimentary-pl utoruc belt referred to as the La Range Domllin. In the area investigated the domajn is composed of the Central Metavolcaruc Belt which is bordered by metasedimentary belts of the Crew Lake and MacLean Lake Belts to the northwest and southeast respectively. The boundaries between the Central Metavolcanic Belt and the flanking belts are generally marked by prominent zones of shearing. The volcanosed imentary succession is intruded by a variety of ultramafic to felsic plutons which, on the basis of lithology, field relations and geochronology, can be broadly subdivided into three groups or episodes. These are: a) an 'early' (ea. 1866 Ma), possibly subvolcanic, episode marked by composite intrusions ranging from gabbro-diorite to granite, b) an 'intermediate' (ea. 1854 Ma) plutonic event distinguished by more homogeneous felsic intru ions ; and c) a 'later' (ea. 1835 Ma) event characterized by leucocratic quartz-rich grani te intrusions. The La Range Domain has undergone polyphase deformation with a strongly developed northeast-trending structural grain. Large scale folding is manjfested by large regional sy nforms, arcuate and triangular patterns associated with many of the plutons and by tight to isoclinal folds within the adjacent metasedimentary belts. Inhomogeneous strain characterizes much of the Star-Waddy Lakes area. With strain gradients being typically very steep, zones of high strain consisting of zones of extreme extensional fabrics, discrete shearing, as well as broader zones of cataclasis and structural slicing, are often juxtaposed with areas of relatively minimal deformation . Dilation structures tend to favour these zones of highly contrasting strain. Late, brittle fractures, faults and shear zones are widespread and appear to be particularly important as loci for gold mineralization. Metan1orphic mineral assemblages indicate that upper greenschist to middle amphibolite facies conditions were attained. Geological and geochenucal evidence indicates that the Central Metavolcanic Belt evolved in an island arc environment. Metavolcanic rocks from both the Waddy and Star Lakes areas display similar characteristics on variation diagrams (e.g. AFM and the Jensen cation plot) in that the dominant trend is calc-alkaline with some basic to intermediate types having a mildly tholeiitic character. A few samples from the southern end of Lower Waddy lake display komatiitic to basaltic-komatiitic afl'injties. The relatively immobile minor and trace elements (e.g. Ti , Zr, Nb, Y, Cr) provide reliable characterization of the metavolcanics, particularly of the basalts, which have highly distinctive trace element properties. Geochemical patterns for the basalts are similar to those for modem volcanic arc basalts. Low initial 87Sr/86Sr ratios (0.7017 - 0.7019) are consistent with a subduction-related origin for the volcanics. The major plutons have chemical properties typical of volcanic arc granites and are largely calc-alkaline in character, showing little chemical variation from the volcanics.

Jan 1, 1986

By Réjean Lévesque

SIDBEC-NORMINES a été incorporée en 1976. Depuis la fin de 1977, ses activités comprennent outre la concentration au lac Jeannine, près de Gagnon, du minerai de fer extrait du gisement du lac Fire, I'exploitation d'un atelier d 'enrichissement secondaire et une usine de bouletage à Port Cartier. L 'objectif principal de SIDBEC-NORMINES est de produire six millions de tonnes de boulettes d'oxyde de fer par année, dont trois millions auront une faible teneur en silice afin de répondre aux exigences de la réduction directe. Les installations de SIDBEC-NORMINES sont adjacentes aux installations portuaires de la Compagnie Minière Québec Cartier, à l'est de la ville de Port-Cartier. L 'ensemble est conçu pour produire les deux types de boulettes avec deux circuits d'agglomération installes en parallèle. La production de concentré enrichi (68% Fe et plus) est obtenue dans une usine d'enrichissement utilisant le precédé de séparation magnétique hum ide ahaute intensite (separateurs Jones). À l'usine de bouletage proprement dite, on effectue Ie broyage du concentré et sa mise en boulettes sur disques; l'in duration des deux types de boulettes est obtenue sur deux chaînes d'agglomération Dravo dont chacune a une capacité annuelle nominale de trois millions de tonnes.

Jan 1, 1979

By G. E. Wittur

"The twenty-one members of the Organization for Economic Cooperation and Development, comprising eighteen western European nations plus Canada, the United States and Japan. account for two-thirds of world steel production. The Special Committee for Iron and Steel was formed by the OECD to study trends and problems in the steel industries of member countries. The paper begins with a summary on the Organization, including an historical sketch, its structure, member-ship and objectives. The steel industry of the entire OECD is briefly described before proceeding to a more detailed discussion of various aspects of the steel industries of European OECD members, emphasizing practices and conditions that differ from those in North America. Benefits to Canada of representation at meetings of the OECD Special Committee for Iron and Steel are described."

Jan 1, 1967

By H. F. Zurbrigg

"The Frood-Stobie Mine is by far the largest metal producer in the Sudbury area. Its efficient development was made possible by the consolidation of three mining properties that covered parts of the same ore body. They were known as the Frood Mine, the Frood Extension, and the Stobie Mine.The southwest or Frood portion of the orebody was discovered by Thomas Frood and A. J. Cockburn in 1884. Cockburn's interest was acquired by J. H. Metcalf and W. B. McAllister and patents were issued to Frood, Metcalf, and McAllister in 1884. The property was purchased by the Canadian Copper Company (lnco) in 1886.James Stobie discovered the northeast or Stobie part of the orebody in 1885. In 1886 Stobie and Rinaldo McConnell applied for the location and patent was issued in 1886. They sold the property to the Canadian Copper Company (lnco) the same year.The Frood Extension property included very little of the ore zone at surface but it covered ore down the dip from Frood. Frank Cochrane was granted title to the property in 1908 and sold it to the Mond Nickel Company in 1910. The title was transferred to the International Nickel Company in 1929 at the time of the Inco-Mond merger.Prior to 1930 the three properties produced a total of about 1 ,000,000 tons of ore from mining done during the periods 1887-1903, 1913-1915 and 1925-1929. Since 1929 the Frood-Stobie operation has produced more than 120,000,000 tons of ore, about half from open pits and half from square set and blast hole stoping. The current production rate is in excess of 6,000,000 tons per year.The principal products from the ore are nickel and copper. The by-products are iron ore, cobalt, platinum, palladium, rhodium, ruthenium, iridium, gold, silver, selenium, tellurium, and sulphuric acid."

Jan 1, 1949

By Fred G. Hewett

Cassiar Mine in northern British Columbia began development in 1952. The deposir is found on rhe west limb of rhe McDame Synclinorium in a Mississippian serpentinite body. The serpenltntte, one of the McDame l ntrusives, imrudes Sylvester Group . rocks, which comprise a Lare Devonian to Early M1ss1ss1pptan eugeosync/inal sequence of argillites, quarrzires and volcanics. The foorwall conracr berween Sylvester Group rocks and rhe serpenrinire is a marked zone of broken and incomperent argillite and graphitic schist. The less marked hang- 111gwall contacr 1s a band of indurated argillite. The JurassicCretaceous emplacemenr of the Cassiar Graniric Barholilh is responsible for mosr of the numerous )aims, faulrs and shear zones found in the serpentinite body. Faulting occurred borh before and after asbestos formation. Asbestos is mined from an open pit ar rhe rate of 4,535 ronnes daily. It passes from the pir along a rramline to the mill, where it is concen/rared into nine direcr milling grades. Packaged fibres travel ro over 40 counrries around rhe world for use in the texrile, cemenr and other industries.

Jan 1, 1984

By Douglas R. Schmitt

In general, knowledge of the state of stress within the Antarctic lithosphere remains largely unconstrained due in part to Antarctica?s inaccessibility and because of the paucity of seismic focal mechanism solutions. As such, an important component of the ANDRILL project was to acquire new information on the stress directions and magnitudes within the upper crust. Extensive fracture mapping of the core and oriented ultrasonic televiewer logging were carried out to provide strong constraints on both stress orientations and the faulting regime. The first hydraulic fracturing stress determinations in Antarctica were also carried out to provide complimentary stress magnitudes. These measurements were accomplished using a wire-line transported hydraulic fracturing system consisting, essentially, of two synthetic polymer packers that were inflated to isolate the 1-m long pressurization interval. The tests were conducted at the end of the drilling and logging in a ~130-m section specially drilled below 1000 mbsf (nearly 1500 m from the rig floor) for hydraulic fractures. This zone was drilled primarily through competent, dense, and low permeability diamicts. The core fracture and televiewer logging information was used to site twenty separate measurements. Classic hydraulic fracturing pressurization records with unambiguous breakdown and fracture closure pressures were obtained in about half of the measurements. The remaining tests provided fracture propagation and closure pressures that are consistent with the classic breakdown curves, but they did not include a clear breakdown pressure and are indicative of the reopening of either natural or drilling induced fractures in the wellbore wall. The preliminary analysis of the results are in generally good agreement with the stress directions indicated by the core fracture logging and the stress regime suggested by the character of the drilling induced core fractures.

Jun 1, 2012

By Janice Zinck

?Past? Images of Mining ?Historic practices have been poor ?Mining still widely perceived as environmental ?spoiler? ?Public only hears the bad news stories. Lessons Learned from the Past ?Sustainability matters ?Recognition of social and environmental responsibilities ?Recognition of importance of public concerns and perceptions ?Community engagement

May 1, 2009

By SANDVIK WHITE

The mining industry produces approximately 4-7% of global greenhouse gas (GHG) emissions. It is fundamental for mining operations to take immediate sustainable action to actively contribute to an emissions-free future for the next generations. The mining industry has traditionally relied heavily on diesel technology and transitioning to more sustainable solutions requires change management to drive cultural acceptance and new product development. Sandvik was interested to find out the lifetime emissions of a single drill rig and to compare similar application diesel and BEV drill rigs with same use profile to each other. That led the calculation and pondering towards comparing different countries and mine sites as well

Jan 1, 2023

By A. H. Mumin, A. K. Somarin, K. S. Oran

"Synvolcanic structures played a fundamental role in the genesis, morphology, and siting of volcanogenic massive sulfide ores and associated hydrothermal alteration in the Archean South Sturgeon Lake caldera complex. The most voluminous and persistent hydrothermal venting and massive sulfide deposition occurred along synvolcanic rifts and grabens associated with faults and tectonic fissures that created permeable fracture zones deep enough to access the underlying hydrothermal reservoir. The type of fracturing is highly variable and changes with the composition, competency, degree of consolidation, and alteration of host rocks. Synvolcanic structures and fracture styles also vary according to the amount and type of tectonic movement, including extension-related collapse, shearing and faulting perpendicular to the principal direction of extension, and orthogonal faulting and shearing. Permeable conduits were created by tension fracturing along fault zones, brittle deformation at the intersections of orthogonal faults, and by extensional fractures in stockworks. In texturally uniform footwall rocks, the distribution of alteration zones was controlled by the morphology of the structural conduit. In rocks with vertical and/or lateral facies, permeability, and competency changes (e.g., Lyon Lake graben), there was an additional stratigraphic control over fluid migration. Some crosscutting synvolcanic structures, alteration zones, and intrusions appear as stratiform units at the present erosion surface due to regional deformation and the present attitude of the volcanic stratigraphy.Hydrothermal mineral assemblages (e.g., quartz, carbonates, chlorite, pyrite, chalcopyrite) infilling structurally induced fractures provide good evidence of fluid migration pathways. However, mineralogy can vary significantly according to the fluid characteristics, host rock geochemistry, and subsequent metamorphic history of the area.Clearly, one of the best methods for locating volcanogenic massive sulfide deposits is to delineate the attitudes of synvolcanic structures, and explore those that show evidence of associated high-temperature hydrothermal mineral assemblages. Excellent exploration targets occur where synvolcanic structures with hydrothermal alteration intersect paleo-seafloor horizons."

Jan 1, 2007

By X. Yuan

"The processing behaviours of ores such as their liberation characteristics in comminution and their response in separation processes are affected by their mineralogical characteristics. Key ore characteristics which are relevant to processing, such as mineral proportions, mineral grain size, grain shape and mineral associations are routinely measured at the micro-scale in polished section using optical microscopes and SEM-based automated mineralogy systems. The application of X-ray micro-tomography to mineral processing provides the means to quantify these important micro-textural characteristics in three dimensions, removing the stereological issues encountered when measuring volumetric information in two-dimensional polished sections. In this paper we present several examples of ore textures to illustrate where X-ray micro-tomography can be applied successfully to obtain quantitative measures of ore characteristics which are useful in a variety of process modelling applications.INTRODUCTION X-ray tomography has been used as a tool in medicine for some years and is being applied in a wider range of fields including geology, palaeontology and mineralogy. In this paper we present some applications of X-ray tomography in mineral processing applications being developed at JKMRC. The availability of SEM-based automated mineralogy systems such as MLA and QEMSCAN has seen the increased use of quantitative mineralogical data measured in two dimensions in the design, operation and simulation of mineral processing plants. When the ore is amenable to measurement by X-ray tomography this technique can provide quantitative data for characteristics such as mineral grain size, shape, mineral associations and liberation in three-dimensions. The advantage of measuring these characteristics in three-dimensions is that the stereological issues which bias measurements made on polished sections are removed. X-ray tomography also quantifies the location of mineral grains relative to one another in space - a useful descriptor of ore texture. Like many measurement techniques X-ray tomography has advantages and disadvantages when compared to other techniques. One limitation is that the ability of the X-ray tomography system to discriminate between minerals is a function of the X-ray attenuation of those minerals. While the X-ray attenuation of many common minerals is sufficiently different for X-ray tomography to distinguish between them, there are some where the overlap in X-ray attenuation makes discrimination on the basis of this characteristic alone impossible. An example of this would be chalcopyrite and magnetite. However where the ore mineralogy is suitable to apply X-ray tomography, the technique provides some exciting opportunities to explore the relationship between texture and ore processability."

Jan 1, 2012

By T. Billotte, G. Tirand, J. Zollinger, V. Robin, B. Rouat, D. Daloz

The grain structure prediction of metallic alloys during a welding process is often an issue. In addition to the welding parameters and the alloy nominal composition and properties, the base metal grain structure and chemical homogeneity also play an important role in the formation of the final microstructure. In this paper intensive characterisation of solidification structure in gas tungsten arc welding of Ni base alloy 600 are described. It is shown that in transverse section of the weld, while the grain structure shows some texture following constrained solidification growth, grain density in the weld is similar or greater than grain density in the heat affected zone. This suggests that simulation of the welding structure needs, in order to be predictive, to take into account : epitaxial growth, secondary nucleation events and 3D growth inside the weld pool.

Jan 1, 2015

By T. A. Lazier, C. S. Longley

"Paymaster Consolidated Mines, Limited, owns several groups of claims in various parts of the Porcupine district. The area in which mining has been carried on includes parts of lots 5, 6, and 7, con. 1, Tisdale township, and twelve adjoining claims in Deloro township to the south. Highway No. 67A between South Porcupine and Timmins crosses the property.The discovery of the Dome mine in 1909 caused a rush of prospectors to the district and in a few weeks practically all territory adjacent to the Dome was staked. At that time work was started on the West Dome, West Dome Lake, Apex, and Standard properties. These were consolidated in 1930 to form the present Company. Gold was produced from the West Dome Lake from 1915 to 1930, and from the Standard-Paymaster from 1922 to 1928. The total production of the previous and present companies from 1915 to November 30, 1946, has been 487,170 oz. gold and 149,342 oz. silver from 2,337,554 tons of ore."

Jan 1, 1954

By C. K. Wilton

"The Agnew Lake uranium deposits were discovered in 1953 following the discovery of the Elliot Lake deposits to the west. The original property was optioned to Kerr Addison Mines Limited who added additional claims by staking. Agnew Lake Mines Limited was incorporated in 1967 to develop the property and a shaft was sunk to 1040 metres and five levels developed before work was suspended due to low uranium prices at the end of1970.In 1974-75 the mine was dewatered and production started in 1977. By 1978 reserves were estimated at 10,000,000 tonnes averaging 0.35 kg. U10 , per tonne. Underground operations were terminated in 1980 although a uranium leaching operation was continued until early 1983.The deposits lie near the contact of Huronian metasediments with underlying Algoman granite. The sediments consist of arkose, conglomerate, argillite and quartzite with the uranium mineralogy mainly confined to oligomictic quartz pebble conglomerate. The higher uranium values are related to conglomerate with highest percentage of pebbles. The chief uranium minerals are uranothorite and monazite. It is of interest that the uranium thorium ratio differs appreciably from that of the Elliot Lake deposits. This fact along with the fact that the Elliot Lake sediments were deposited by paleocurrents from the northwest whereas the Agnew Lake sediments were deposited by paleocurrents from the northeast indicates widely separate sources for the deposits. It is suggested that the Agnew Lake uranium deposits are syngenetic placers deposited under anoxygenic atmospheric conditions."

Jan 1, 1986

By W. F. James

"The property of Siscoe Gold Mines, Limited, comprises about 1,600 acres, including Siscoe island and adjacent claims under water in Montigny lake, in Dubuisson and Vassan townships, Quebec.For many years the property was reached by way of Harricana river and its chain of lakes from Amos, Quebec, about 45 miles distant. In later years a highway has been built from Noranda east through Val d'Or, about 5 miles distant.Gold was discovered on one of the claims on the north shore of Montigny lake as early as 1911, but these gold discoveries have never been economically important. Several years later gold was discovered on Siscoe island and considerable surface work was carried out. Still later, iscoe Gold Mines, Limited, was formed and carried out further work, some of it through shallow shafts. In 1928, larger scale operations were undertaken and a 100-ton mill was constructed. In the years following, production· was on a larger scale with lower grade, until finally a milling rate of over 1,000 tons a day was attained. Approximately 1,500,000 tons were treated between the end of 1940 and mid-year 1945. At present the milling rate is down to about 200 tons a day and work is confined chiefly to some of the less important veins that have been recently developed.The following is a summary of production up to December 31st, 1946:"

Jan 1, 1954

By T. R. Stanley

Introduction The purpose of this paper is to interest mining men in the economic possibilities of sand deposits suitable for modern foundry work. Many members of the profession are constantly travelling over the country and it is felt that some knowledge of the necessary properties of foundry sands will enable these men t0 recognize such deposits. It is the experience of the writer that good sands suitable for the varied work of a foundry, such as that of the Consolidated Mining and Smelting Company, at Trail, are almost impossible to obtain from western Canadian sources. It is hoped that the following discussion may arouse some interest in the search for such sands. Sands are used in foundries for two purposes. The main use is for making moulds suitable for receiving hot metal. The mould must retain the? required shape until the metal has solidified. The second use of sand in the foundry is as an abrasive in sand blasting. This is a relatively minor use, and consequently will not be dealt with in detail. Any coarse sand with a high content of quartz will serve this purpose, but round-grained sands are superior to angular types, because they have not the same tendency to shatter on impact with the casting. Sand plays an extremely important part in the successful production of sound castings. This is more evident today than ever before, due to the greater variety of castings and alloys, each of which requires special sand characteristics. Poor sand is responsible for a great many foundry troubles which formerly were attributed to bad? metal; in fact, one investigator goes so far as to say that ninety per cent of bad castings can be traced directly to the sand. Very little of the vast amount of sand distributed over the earth's surface is suitable for moulding. It is the purpose of this paper to describe briefly the properties which are essential in good moulding sand. Sand for this work must be able to withstand the wash and hydrostatic pressure of molten metal, and yet be sufficiently porous to allow the gases generated in the mould to escape.

Jan 1, 1935

By Chris Twigge-Molecey

"Over the last 50 years there has been a dramatic evolution in the metallurgical engineering field in Canada. In the 60s the field was dominated by large American and UK groups, often selling major process and equipment packages. The local content was limited to wrap around facilities and the civil and structural work. The mining and metallurgical companies had strong internal teams to lead these projects. Over the decades and business down cycles the large foreign contractors disappeared or re-structured and the mining companies largely shed their engineering and project management groups. The resulting gap was filled by a cadre of local specialist engineering companies, some of whom have grown to be world leaders in the field. The paper traces this evolution and examines the underlying causes and consequences."

Jan 1, 2015

By K. Bullock, M. Levesque, G. Lyle, D. L. Millar

ABSTRACT The options for reducing the carbon footprint of energy use in mining fall into three categories of activity: i) reducing demand, ii) improving energy utilization, and iii) adopting low carbon energy technologies. In addition to the environmental imperative, the economic case for these activities gains higher priority as the prices of electricity, gas, and liquid fuels increase. Low-carbon, energy-saving technology options that are available to mining industry companies lead to projects with return rates that must compete alongside other capital-intensive projects considered by mining company boards. Energy projects frequently involve longer payback periods and lower rates of return than those of competing bids for capital, such as new mineral property developments. For energy services companies that specialize in the financing, construction, efficient operation, and maintenance of energy projects, the same returns and payback periods can be considered acceptable or even attractive.

Jan 1, 2012

By Robert Maquil, Gilles Didier, Walter Steiner

"The 1580 m long dual-tube motorway tunnel Markusberg near Schengen, Luxembourg experiences strong swelling phenomena in each tube related to a 35 m wide diagonally crossing rock layer, some150 to 200m from the east portals. Overburden over the roadway is 26 to 30 meters. Tunnel construction started in 1998 and the tunnel was opened in 2003. The tunnel was driven downgrade from the West, the heave phenomenon started to occur as the tunnel approached completion. No indications of the presence of anhydrite and dissolved sulphates were known prior to tunnelling. Water samples had been taken from the beginning of construction and the concentration of anions and cat ions determined. Sulfate content was substantial, in one well it reached 22 mg/l, this high concentration requires the presence of other ions, in particular sodium and chlorine. Based on the knowledge at the time of construction heaving ground was removed from the tunnel invert and a free space was left below the roadway that is covered by a transversely spanned slab. In addition a series of posttensioned tiebacks were installed below the sidewalls. The void left in 2003 was 1.7m high and closed to less than 0.5 meters in 2007 then it became necessary to widen the free space. A central trench was dug with a height of about 2.5 meters and the benches were lowered.Level surveying had been carried out since 2002. In 2006 two extensometers were installed, one in the zone of strongest heave, the second at the edge of the swelling zone. The extensometer in the center of the swelling zone indicated heave with an essential constant rate with seasonal variations, the heave is concentrated in layer from 2 to 5 meters that heaved by nearly 300 millimeters within 5 years or 60 mm/year, which equals to approx. 1% extension per year. At the abutments heave rates of 20 mm/year where the support resistance is higher were observed. With data from other case histories a relation of heave rate with support resistance was established. Based on the numerous field observations hypotheses for the complex in-situ swelling processes, involving rock mechanics, mineralogical, soil mechanics and hydrogeological aspects were developed"

Jan 1, 2015

By V. S. Sastri, M. Elboujdaïni

"Corrosion rates of silicon brasses, highzinc yellow brass, low-zinc yellow brass, leadedtin bronze and silicon bronzes in both permanent-mold and sand-cast conditions were determined in soft water of pH 3, 5 and 8, and hard water of pH 8 at 70°C by electrochemical polarization technique. The alloys in permanent- mold condition showed greater corrosion resistance than sand-cast condition. Corrosion rates obtained from weight loss measurements showed no observable trend of a difference between permanent-mold and sand-cast alloys.The corrosion rates decreased with increasing pH of the medium. Silicon bronze and silicon brass showed high corrosion resistance while leaded-tin bronze showed the least resistance. Addition of small amounts of aluminum improved the corrosion resistance of silicon bronzes and silicon brasses. Alloys in permanent- mold condition showed greater resistance to dezincification than sand-cast alloys when average pit depth parameter is considered."

Jan 1, 1997