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By S. Joshi, E. Asselin

An electrochemical quartz crystal microbalance (EQCM) was used to study the leaching of pure gold in deaerated 1 M Na2S solution. Multiple cyclic voltammograms were measured between -0.76 and 1.242 V (SHE) at 20 mV/sec and 2 mV/sec and the frequency shift of the quartz crystal was simultaneously measured. Both the forward and reverse scans showed oxidation occurred between -0.40 to 0.20V. The frequency shift increased during both the forward and reverse scans in the potential range of -0.40 to -0.06 V indicating electrode mass decreased. Since at -0.40 to 0.20 V oxidation peaks were also observed, part of the oxidation was due to oxidation of gold. Eh-pH diagrams were constructed and showed soluble Au(I)-S(IV) species formed between -0.30 and 0.10 V (SHE). Atomic absorption spectroscopy of the test solutions and the mass change recorded by EQCM both showed about 0.015 mg of gold leached. Since the majority of the frequency shift increase corresponding to gold oxidation occurred at -0.40 to -0.06 V during multiple cyclic voltammogram measurement, the total leaching of gold could be approximated to occur at this potential interval to give a leaching rate of ca. 6.4x10-5 mg/s-cm2.

Jan 1, 2011

By A. T. GRIFFIS, R. J. GRIFFIS

A large magnesite-talc body is locared in Delora Township, 11 km sourh-southeasr of Timmins, Onrario. The deposit occurs in part of an Archean greensrone belt dominated by volcanic and sedimenrary rocks and large bodies of ultramafic intrusions. The magnesite-talc zane is abour 1800 m long, has a maximum width of 300 m and has been drilled ro 120 m below surface. Chemical analyses of rhe main carbonate zane average 20 ro 28% soluble MgO (magnesia), 5 ro 6% rota/ iron oxide and less rhan 0.1 % CaO (lime). Mineralogically, the zane consists of approximately 54% magnesite, 28% rate, /5% quartz and 3% hematire. Perrographic srudies suggest that rhe various assemblages of magnesite, rate, quartz and serpentine were derived from a parenr serpenrinire (after dunire). An early carbonitization stage, which produced a high-magnesite, low-talc assemblage, preceded a farer decarbonitizarion stage, which formed rhe main magnesite-talc assemblage. Despite a favourably low calcium oxide content of rhe magnesite-talc rock, considerable iron in the magnesire /at rice has limited the quality of the beneficiared product: rhe besr flotation concentrate to dare yields 92 to 94% dead-burned MgO. Experimen- I L t r i i c:~:.•-4- -------- ? -_;> ,•----1---- ta/ work continues on finding a process whereby high-purity magnesia can be produced on a commercial scale.

Jan 1, 1984

By H. Nakano

The codeposition behavior of impurities such as Ag, Bi, Fe, Ni, Pb and Sb with Cu was investigated galvanostatically at 5-3000 A/m2 using a Pt cathode at 60 °C in acidic copper (I) chloride (cuprous chloride) solution at pH1-2 containing 1.0 mol/L of Cu+ and 4.9 mol/L of Cl-. The impurities were classified into two groups: Group I (Ag, Bi) which codeposits with Cu as a metal, and Group II (Fe, Ni, Pb, Sb) which is slightly involved in the deposited Cu in nonmetal form from the electrolyte. Silver and Bi in Group I behaved as more noble metals than Cu, and significantly codeposited with Cu, showing typical features of regular-type codeposition. When Cu was deposited dendritically, the Ag and Bi content in the deposit increased with increased duration of electrolysis as a result of decreased net current density caused by increased cathode area. The current efficiency for Cu deposition in impurity-free solution was 95-100% over 100-1000 A/m2, but it abruptly decreased at above 1000 A/m2 when the limiting current density of Cu was attained. Although Fe, Ni, Pb and Sb in Group II were involved to 0.01-0.02 mass% in the deposit, they had no influence on the current efficiency or morphology of Cu.

Jan 1, 2007

By M. Peshko, J. C. Gingerich, L. W. Matthews

"Noranda has successfully developed and implemented two leading-edge mineral exploration technologies — hyperspectral remote sensing and 3-D seismic surveying. Airborne hyperspectral imaging provides detailed geological and mineralogical mapping capability at both a regional and project scale that facilitates improved selection of prospective terrain and an accelerated exploration cycle. Noranda, in partnership with Falconbridge, has licensed the exclusive use of the Earth Search Sciences Inc. (ESSI) Probe-1 hyperspectral scanners (128- channel, 0.43 µm to 2.5 µm spectral range) that are capable of mapping in excess of 3500 km2 per day at 10 m pixel resolution. The technology has been successfully deployed on four continents over a broad range of terrain from desert to boreal forest and the high Arctic.To augment the company’s deep search initiatives, Noranda has successfully modified and implemented existing 3-D seismic technology to help targeting massive sulphides located at depths ranging from 500 m to 2000 m. In the fall of 1998 and early 1999, Noranda completed an 18 km2, 3-D seismic program in eastern Canada by successfully drill testing acoustic impedance anomalies locating massive sulphides at depths in excess of 1100 m."

Jan 1, 2002

By P. West-Sells, B. Wassink, N. Fisher

Gold leaching from a commercial cyanide-amenable gold ore was studied at 25°C using sodium bisulfide-hydrogen sulfide solutions containing elemental sulfur. Gold extraction from the ore using 0.55 M NaSH, 4.1 atm (60 PSI) H2S, 1 g/L S8 and 26% solids by weight was about as good as the best extraction obtained by cyanidation. Maximum extraction was achieved in roughly 48 hours. Sulfur dissolves in the bisulfide solutions to form a mixture of polysulfides. Simple speciation calculations indicate that gold solubility as bisulfide complexes should be roughly ten times higher than in the absence of added zerovalent sulfur. The principal bisulfide complex is believed to be [Au(HS)2]-. Gold dissolution is favoured by increasing HS- concentration and by increasing H25 pressure. Polysulfide complexes of gold are also likely to be formed, and may contribute substantially to gold leaching. Two experiments using pure gold were also performed. Up to 100 mg/L gold was dissolved in 140 hours using 0.55 M NaSH, 1 g/L added elemental sulfur and 6.2 atm H2S.

Jan 1, 2005

By R. Ghomashchi

Wear, fatigue and corrosion are the most widely encountered modes of failure in materials used in engineering applications, including aero-gas turbines. Although wear is distinctly classified as adhesive, abrasive, erosive, fretting and so on, there are usually more than one wear mechanism involved in the failure of components in service because there are many systems and materials variables active in materials wear that makes it more difficult to study. This is further complicated by the discrepancies between the results of laboratory tests and field data. The present investigation was set up to examine the wear characteristics of M50 and T1 high-speed steels at both room and elevated temperatures to draw a thorough understanding of the wear behavior of this class of high-speed steels. This article focuses on the mechanical and microstructural characterization of wear for T1 and M50 high-speed steels using a pin-on-disk wear machine.

Jan 1, 2005

By J. Mizera, J. Zdunek, K. J. Kurzydlowski, A. Dobkowska

This work concerns comparison of corrosion resistance of the aircraft aluminum alloy composed of Al - 2.3%Li - 0.1% Zr. The alloy was hot rolled (HR) from 13 mm to a thickness of 4 mm (e = 2.4) and 1 mm (e = 5.2). Corrosion resistance was investigated by Potentiodynamic Polarization Test. The investigation relied on exposure samples in two different corroding medium: 0.5 M NaCl solution and 0.01 M Na2SO4 solution with added 0.01% of Cl- at room temperature. Furthermore, the microstructure was analyzed using the optical microscope with polarized beam. The hardness was measured on lengthwise profile. It was stated that alloy after the largest deformation (equivalent total strain e = 5.2) is characterized by the best mechanical properties and the best corrosion resistance. The alloys in initial state and after deformation to 4 mm (e = 2.4) are characterized by worse corrosion resistance. It is associated with microstructure and density of dislocation in analyzing material.

Jan 1, 2015

By E. T. C. Spooner, Ioannou S. E.

"Abstract- The Dixie Zone Au-Ag deposit is a low sulfidation (adularia-sericite) epithermal system located 1.4 km from the producing Ken Snyder mine (7.0 M oz Au equivalent reserve/resource), Midas Mining District, north-central Nevada. This WNW striking, steep south dipping, fault system is hosted by mid-Miocene (17 Ma to 14 Ma) felsic volcanic rocks that were erupted from a vent(s) to the northeast. The system was mineralized by approximately 250 ± 20°C (n = 86), near-neutral pH, ascending fluids of predominantly meteoric origin [volatile corrected salinity = 0.52 ± 0.35 eq.wt% NaCl (n = 86)]. Bulk analytical fluid inclusion gas chromatography identified a mineralizing fluid volatile composition of 99.68 ± 0.18 mole % H2O, 0.16 ± 0.09 mole % CO2, 0.11 ± 0.05 mole percent N2, 0.05 ± 0.04 mole % CH4, and 0.01 ± 0.01 mole % CnHn+i (n = 7). Sulfur species were not analyzed due to absorption within the chromatography system; however, a H2S concentration of 16 ppm to 160 ppm molar is estimated. The volatile content contributes approximately 50% of the microthermometrically measured freezing point depression. Cl- concentrations up to approximately 9000 ppm suggest an additional, probably magmatic, fluid component.Ascending fluids were channelled along approximately NW striking faults related to the same primary extension (17 Ma to 14 Ma) responsible for Nevada basin and range physiography. Boiling induced by CO2 effervescence led to precipitation of Au and Ag over a 150 m vertical interval. At the time, this interval was about 460 m below the water table (approximately 38 bars), but because of erosion, it is now within 90 m of the surface. A Ag:Au ratio of 25:1 has been calculated for the Dixie Zone."

Jan 1, 2000

By E. Ghali, N. Sorour, G. Houlachi

"The binary Fe53Mo47 and ternary Fe54Mo30P16 coatings have been electrodeposited from citrate-based electrolyte on mild steel (MS) substrates. The electrodeposition has been conducted for 6 hours at 20 mA cm-2 and 30°C. The electrochemical tests were carried out in chlorate solutions containing 300 g L-1 NaCl and 4 g L-1 K2Cr2O7 at pH 6.4 and 80°C. A number of surface characterization techniques such as SEM-EDS, XRD and EMP were used to study the microstructure of the alloys. The electrocatalytic activity of these coatings was investigated using steady-state polarization and galvanostatic technique. This study revealed that the Fe-Mo-P coating could be considered as a promising cathode material for the hydrogen evolution reaction (HER). The results showed an important decrease of hydrogen overpotential for Fe-Mo-P alloy as compared to that of Fe-Mo and especially MS which is a traditional cathode in chlorate industry. The HER overpotential for Fe54Mo30P16 at current density of 250 mA cm-2 was decreased by 30% in comparison to that of MS (1029 mV), and by 16.5% to that of Fe53Mo47 coating (857 mV).INTRODUCTIONSodium chlorate is used for manufacturing of several daily consumption products. This chemical is mainly employed for the production of chlorine dioxide (ClO2) that is a bleaching agent used in the pulp and paper industry. The ClO2 is also consumed for generation of perchlorates, chlorites and other chlorates, as an herbicide and in uranium processing (Cornell, 2002). Sodium chlorate is produced industrially via following overall formula in un-divided electrochemical cell (Nylén & Cornell, 2009):"

Jan 1, 2016

By C. W. Hancher, B. D. Patton, W. W. Pitt

"There are a number of nitrate-containing wastewater sources, as concentrated as 30 wt % NO3 and as large as 2000 m3/day, in the nuclear fuel cycle. The biological reduction of nitrate in waste water to gaseous nitrogen, accompanied by the oxidation of a nutrient carbon source to gaseous carbon dioxide, is an ecologically sound and cost-effective method of nitrate waste disposal. These nitrate-containing wastewater sources can be successfully biologically denitrified to meet discharge standards in the range of 10 to 20 g N(NO3-)/m3 by the use of a fluidized bed bioreactor. The denitrification bacteria are a mixed culture derived from garden soil; the major strain is Pseudomonas. In the fluidized-bed bioreactor, the bacteria are allowed to attach to 0.25- to 0.50-mm-diam. coal fluidization particles, which are then fluidized by the upward flow of influent wastewater. Maintaining the bacteria-to-coal weight ratio at approximately 1:10 results in a bioreactor bacteria loading of greater than 20,000 g/m3,This paper describes the results of a bio denitrification R&D program based on the use of fluidized bioreactors capable of operating at nitrate levels of up to 7000 g/m3 and achieving denitrification rates as high as 80 g N(N03-) per day per litre of empty bioreactor volume. IntroductionThe discharge of wastewater containing nitrate at concentrations greater than stipulated by the Environmental Protection Agency (EPA) creates an environmental hazard and constitutes a civil and/ or criminal legal liability.(I.2) At present, we have three options: (1) recycle and reuse of nitrate streams the total economic and technical balance should be Closely examined; (2) use of an alternative acid, which may pose an entirely different set of problems ; or (3) disposal of nonreusable nitrate sources by an environmentally acceptable procedure."

Jan 1, 1980

By D. A. Peterson, R. Pakalnis, G. Peter Mah

"Laboratory and trial installations have been completed to determine the potential of composite cable bolt reinforcement in Canadian underground mines. Several prototypes of glass fibre cable bolts have been developed and tested, two of which are currently available to the mining industry. Their evalualtion consisted of lab testing in Canada and the United States, along with trial installations in several underground mines throughout Canada. The objective was to develop a cost competitive composite cable bolt equivalent in strength to that of a 16 mm (Ys in.) diameter steel cable bolt. In addition to achieving equal or superior load carrying characteristics in tension, the glass fibre cables generally experienced an increase in the rate of installation due to their lighter weight. Unlike conventional steel cables, composite cables may be installed within mines which utilize continuous excavation and which require cuttable support. A market analysis of cable bolt usage in Canada has been completed. Glass fibre cable bolts are an effective means of rock reinforcement in mining applications. They prove to be a viable alternative to conventional steel cable bolting. IntroductionCurrent cable bolting practice consists of cement grouting one or more steel cables within a drill hole in order to support the surrounding rock mass. Cable bolts are a form of internal support and are generally used as pre-support in open stope and cut-and fill mining methods. They can be either tensioned (active support) or untensioned (passive support) and may be of any length, though for underground mining applications, are generally less than 20 m (65.6 ft) and are untensioned. A major advantage of cable bolts is that they are flexible and can be coiled to approximately 1 m (3.3 ft) diameter coils. This allows relatively long lengths (>20 m, [65.6 ft]) to be installed in areas with limited head room (1.8 m)."

Jan 1, 1994

By Richard J. Haslinger, C. Mark Rebagliati, James L. Oliver

Abstract - Exploration at the Specogna gold deposit has identified a geological resource of 65.0 Mt grading 1.63 g/t Au, which equates to 3 million ounces of contained gold. This resource is hosted in a low-sulfidation epithermal deposit of Miocene age that is localized along the northwesterlytrending Sandspit fault. The fault has juxtaposed Late Cretaceous mudstone of the Haida Formation to the west, with Late Tertiary coarse clastic sediments and lesser andesitic volcanic rocks of the Skonun Formation to the east. A plagioclase porphyritic dacite dike intrudes the Haida mudstone and Skonun sediments along the fault. Gold mineralization, in hydrothermal breccias, veins and stockworks developed mainly in Skonun sediments and dacite. These are formed in an 800 m long zone that roughly parallels the Sandspit fault. The gold zone is funnel-shaped in cross-section, approximately 300 m wide at surface, 220 m above sea level, and narrows to approximately 50 m, at sea level. The deposit lies within an elongate zone of moderate to intense hydrothermal alteration that, at surface, extends over a known area of approximately 2 km2. Its western extent is bounded by the Sandspit fault. There is an asymmetric alteration zonation, with a core of silicic-potassic (adularia) and smectite-illite clay alteration that is bounded to the east by argillic alteration. Similar zoning defined by the distribution of metals reflects the position of the main feeder conduit. Mineralization of altered wallrock is dominated by 1% to 4% auriferous pyrite and marcasite. Gold and silver occur as electrum; individual silver minerals have not been identified. Other sulfides are rare, and are identified only microscopically. The mineral suite is typical of low-sulfidation epithermal systems. Gold occurs in early, multi-phase, variably bladed and banded quartz veins and breccias, which are cut by barren, single phase, drusy quartz veins.

Jan 1, 1998

By Paul L. Broughton

"IntroductionThe coal deposits, all of lignite rank, of economic interest in Saskatchewan are associated with the Ravenscrag Formation (Paleocene). Several Cretaceous formations have less significant lignite accumulations (Broughton, Irvine and W'hitaker, 1974). The Swan River Group (lower Cretaceous) and Judith River Formation (upper Cretaceous) have the only coalbearing strata in the shallow subsurface of central Saskatchewan. The Swan River Group coalfield is relatively small and underlies only 15 sq km of the surface approximately 40 km south of La Ronge, Saskatchewan. An estimated 36 billion short tons are within 45 m of the surface. No reserve estimates are known to have been calculated for the coal-bearing Judith River Formation exposed at the surface in the vicinity of the South Saskatchewan River valley in west-central Saskatchewan. Although no coalfields have been delineated, lignite beds up to 1.8 m thick have been intersected in test holes. The coal-bearing upper Cretaceous and lower Tertiary strata of the northern Williston Basin extends the full width of southern Saskatchewan for 650 km, and from the United States border 120 km north to 50° latitude (Fig. 1). Only the coalfields of the Ravenscrag Formation, because of their economic interest, will be considered further. There are four major coalfields. They are, from east to west: Estevan, Willow Bunch, Wood Mountain and Shaunavon (Cypress) coalfields. Cumulative lignite seam thickness for each basin is 10 -15 m (Figs. 2 and 3). The origin of each coal basin, resource calculations, seam stratigraphy, and mining activity are discussed. Regional Setting The Williston Basin is an ellipsoidal depression in the Precambrian basement, centered in western North Dakota and marginal to the exposed craton of northern Saskatchewan and central Manitoba (Fig. 1). The sediments of the basin range from Cambrian to Pleistocene in age and have a maximum known thickness of 4614 min western North Dakota. A maximum of 3200 m is recorded in southern Saskatchewan. Most structural deformation is late Cretaceous to early Tertiary (Paleocene) in age, coinciding with the Laramide Orogeny. The pre-Laramide Williston Basin, with a depocenter near Williston, North Dakota, began developing during the middle Ordovician, or possibly earlier."

Jan 1, 1985

By G. Graves, J. A. Walker

"Abstract - The Mount Fronsac North volcanogenic massive sulfide deposit is the most recently discovered massive sulfide body in the Bathurst Mining Camp. The deposit occurs within a sequence of intercalated fine-grained felsic tuff and sedimentary rocks (Little Falls member), at the top of the Nepisiguit Falls Formation. Aphyric to sparsely feldspar-phyric rhyolite and related volcanic rocks of the Flat Landing Brook Formation overlie the host sequence. The massive and semimassive parts of the deposit have a north-south strike length of 525 m and a dip of ~45°E; the deposit is continuous downdip for 600 m, and thickness varies from 2 to 20 m. The deposit contains an estimated geologic resource of 14 Mt of low-grade, semimassive (>60%) to locally massive sulfides, and includes a high-grade zone of 1.26 Mt grading 7.65% Zn, 2.18% Pb, 0.14% Cu, 40.3 g/t Ag, and 0.40 g/t Au. The semimassive to massive sulfide intersections occur in an envelope of quartz-sericite±chlorite schist, which is interpreted to be intensely deformed felsic tuff. This sequence has a maximum thickness of 140 m and contains significant (up to 50%) fine- to coarse-grained disseminated pyrite. The pyritic envelope has a strike length of 900 m and extends over 1000 m downdip. Massive sulfides are found throughout this alteration envelope, but more commonly occur at or near the upper contact. The significance of the discovery of this deposit is that it represents a near surface discovery of a large tonnage sulfide body in a mature mining camp, one in which the possibility of discovery of a new shallow deposit had been all but discounted. This opens the possibility for future discoveries in this part of the Bathurst Mining Camp. Sommaire - Le gîte de sulfures massifs volcanogènes du Mont Fronsac Nord est la découverte de sulfures massifs la plus récente dans le Camp Minier de Bathurst. Le gisement est situé dans une séquence de tufs felsiques à grains fins interlités de roches sédimentaires (membre de Little Falls, au sommet de la Formation de Nepisiguit Falls. La partie massive et la semimassive s’étendent du nord au sud sur 525 m et ont un pendage de ~45°E; le gisement est continu sur 600 m en angle de chute et son épaisseur varie de 2 à 20 m. Le gisement contient une ressource géologique évaluée à 14 Mt de sulfures semimassifs (>60%) localement massifs à basse teneur, incluant une zone à haute teneur de 1.26 Mt titrant 7.65% Zn, 2.18% Pb, 0.14% Cu, 40.3 g/t Ag, et 0.40 g/t Au. Les intersections de sulfures semimassifs à massifs se situent dans une enveloppe de schiste à quartz-sericite ± chlorite interprétée comme un tuf felsique intensément déformé. Cette séquence contient une quantité importante (jusqu’à 50%) de pyrite disséminée dont le grain varie de fin à grossier et son épaisseur maximale est de 140 m. L’enveloppe pyriteuse s’étend latéralement sur 900 m et a été tracée jusqu’à 1000 m en angle de chute. Des sulfures massifs sont trouvés partout à l’intérieur de cette enveloppe d’altération, mais ils sont plus fréquents près du contact supérieur. L’importance de cette découverte tient à ce qu’elle est un exemple d’un gisement à fort tonnage nouvellement découvert à une faible profondeur dans un camp minier mature, i.e., un camp ou l’on ne croyait plus qu’il était possible de trouver un gisement près de la surface. Ceci ouvre la porte à la possibilité d’autres découvertes dans cette partie du Camp Minier de Bathurst."

Jan 1, 2006

By O. Rabeau, M. Legault, A. Cheilletz, L. Z. Cheng, J. J. Royer, M. Jébrak

"By compiling geological, structural, geophysical, and geochemical information into a 3D geological model, we evaluated the orogenic gold potential in the vicinity of a hidden segment of an important Archean fault zone, the Cadillac-Larder Lake fault (CLLF) in the region of Rouyn-Noranda. The segment of CLLF in the present study is partly covered by Proterozoic sedimentary rocks. Because more than 2000 t Au have been extracted along the CLLF to date, our objective is to evaluate the gold potential at depth along a poorly known segment of this fault. A 3D geological model (50 km × 9 km × 1.5 km) including the covered segment was built through the compilation and homogenization of available geological data and the construction of 23 cross sections. The geology under the Proterozoic cover was evaluated using geophysical inversions, drill holes (42 in total), and surrounding geology. All available assays were filtered and upscaled to a 250 m × 250 m × 250 m regular cell grid to determine and quantify spatial relationships between geological features and mineralized occurrences using the weights of evidence method. Structural features, such as E-W-trending faults and fault intersections, and certain lithologies with a high primary porosity such as volcanoclastic rocks of the Blake River Group and Timiskaming sedimentary rocks, proved to be very prospective, yielding favourable factors with a weight of evidence index W+ > 0.24. These salient features were then assigned a combination index for ultimately evaluating the orogenic gold potential under the sedimentary cover. The zones resulting in an optimization of exploration targeting were attributed the highest probability, representing ~1% of the initial volume. La compilation des données géologiques, géophysiques, structurales, et géochimiques et leur intégration au sein d’un modèle géologique 3D a permis d’évaluer le potentiel aurifère dans les environs d’une importante zone de faille archéenne sous couverture protérozoïque. Cette méthodologie a été développée en utilisant le cas de la Faille Cadillac-Larder Lake (FCLL) dans la région de Rouyn-Noranda. Puisque plus de 2000 t d’Or ont été extrait à proximité de la FCLL, l’objectifs des travaux est l’évaluation du potentiel aurifère en profondeur de ce segment. Un modèle géologique 3D (50 km × 9 km × 1.5 km) incluant le segment sous couverture de la FCLL a été construit en utilisant l’ensemble des données géologiques disponibles et 23 coupes géologiques. La géologie du socle archéen sous la couverture protérozoïque a été interprétée avec des inversions géophysiques, des forages (42 au total) et les contacts géologiques exposés. Les teneurs aurifères dans le secteur ont été filtrées et ajusté à une grille régulière de 250 m × 250 m × 250 m afin d’évaluer et de quantifier les relations spatiales existantes entre certaines entités géologiques et les emplacements minéralisés en utilisant la méthode du poids de la preuve. Les failles de direction Est-Ouest, les intersections de failles ainsi que certaines lithologies possédant une porosité primaire importantes comme les certains tuf du Groupe de Blake River et les sédiments du Timiskaming se sont montrés très prospectifs avec des valeurs de W+ > 0.24. Ces entités géologiques ont ensuite été utilisées par le biais d’un indice de combinaison pour évaluer le potentiel en or de type orogénique sous le couvert sédimentaire. Cette méthodologie permet une optimisation des campagnes d’exploration puisque les zones pour lesquelles la probabilité de minéralisations a été évaluée à la plus haute valeur représentent 1% du volume initial."

Jan 1, 2009

By A. Mehinrad, F. Rafia

"The Dez River flows from the Zagros Mountains into the great Khuzestan plain, Southwest of Iran. The 203 m high Dez Dam is a double curvature thin concrete arch dam, with a Pulvino, founded on thick bedded to massive conglomerate of Bakhtiary Formation, mainly horizontal and very less jointed at the dam site. Construction work was completed in 1963, creating a reservoir with a total storage volume of 3’315 million m3. The dam body, with some 350’000 m3 volume and (W/H=1.1/1.0), is the dominant feature of the project.Geological and geotechnical studies at the dam site started in 1957 and continued during the whole period of dam construction. Simultaneously, two extensive programs of laboratory testing were carried out in New York and Milan.Most of the results were recorded in the project design documents and in two very well-known papers of Talobre et. al. (1964) and Dodds (1966), however, no detail results are available for most of tests.In order to estimate geomechanical parameters of the rock mass foundation for numerical modeling of the dam body and its foundation, reassessment of the in-situ and laboratory test results using the recent rock mechanics methods was required.This paper explains how the outcomes of those tests, performed more than 50 years ago, were reevaluated and how the definitions and parameters presented in the project reports were re-interpreted using the recent rock mechanics concepts and definitions. Also, the results of classification of Bakhtiary conglomerate using GSI system and application of Hoek & Brown failure criterion for estimating rock mass parameters have been described.INTRODUCTIONThe Dez River flows from its headwaters in the Zagros Mountains into the great Khuzestan plain. Just before entering the plane, the river passes through a narrow, steep gorge that is about 17 km long. The Dez Dam is located at the entrance to this gorge, some25-km upstream of the city of Dezful and 150-km upstream from the provincial capital Ahwaz (Figure 1)."

Jan 1, 2015

By A. L. Rutledge, R. S. Nichols

"Waste dump development at the Fording River Operation s in British Columbia began in 1971. In 1981, several unique as well as unplanned situations provided an opportunity to study water flows through waste dumps.The key to the drainage is naturally segregated rock sizes .created by end dumping from the crest of a pile. The largest size material accumulates at the toe. Flow rates along the base of the studied dumps varied from 2,800 to 13,500 m3/day or 0.032 to 0. 156 m3/s (1.2-5.5 cfs}. Sediment concentrations in the water ranged from 1 to 1,800 mg/I.This paper describes water flows through dumps of varied lithology and maturity. The results suggest that neither long-term water flow nor contained sediments in small streams are jeopardized when crossed by end-dumped fills.IntroductionThe Fording River Operations are located in southeastern British Columbia approximately 115 km north of the United State s and 10 km west of Alberta, within the medial range of the Rocky Mountains. All production is carried out at elevations ranging between 1,600 and 2,200 m above sea level.The property is within a continental climatic zone, with temperature extremes of - 40°C in January to +35°C in July. The average annual precipitation of 335 mm of rainfall and 390 cm of snowfall feeds the numerous seasonal, small drainage courses along the Fording River valley.Since start-up in 1971, 149 million bank cubic met res of waste from truck-shovel and dragline mining have been placed in numerous dumps or ""spoils"". The dumps were developed to the point that several unique situations could be studied. During the peak run-off period of May-June 1981, water flow studies were performed on dumps of varied lithology and maturity. This paper describes the results of the study."

Jan 1, 1982

By Stephen Mullowney

Outline ? Setting the stage ? Deal activity ? Q1 2013 update ? Key deal sectors ? Deals by geography ? Outlook for 2013 Key Observations 2012 ? Major retreat in M&A activity ? Glencore-Xstrata deal dwarfs all other deals ? Gold & copper dominate deal activity

May 1, 2013

By A. Torkian

Process water from production of concentrates in Meydook copper sulfide mine is transferred to the 8.3 million m3 tailings dam and a water retention pond after initial thickening. Elevated concentrations of heavy metals, sulfate, and TDS and decrease in pH as well as seepage into the aquifers have been the concern of the regulatory agencies since the start of activities. In this paper the results of a 6-month monitoring program from 4 wells are presented. The wells were located approximately 1.5 km from downstream of tailing dam (0.4 km from water retention pond) as well as upstream background well (2.28 km from water retention pond and 1.27 km from tailings dam). The objective was to study possible effect of accumulated tailings on the groundwater resources. Water levels in sampled wells were on average between 20 and 40 m. Results showed high levels of lead (5 ppb), copper (0.17-0.46 ppm) and selenium (73.1- 29.1 ppb). High levels of selenium and lead were partly due to natural geological settings of the area with high levels present in unaffected soils in the vicinity including water wells of villages upstream of mining operations. High copper levels were attributed to both mining operations as well as deposition from particulate air deposition onto the soil and transport to ground water by rain.

Aug 1, 2013

By S. Shimaya, T. Maejima, M. Shimo

"The authors conducted the in-situ gas-tightness tests in a fractured rock at the Namikata underground LPG storage site in Ehime prefecture, Japan. The test consisted of two independent setups, a gas-tightness test that used boreholes, and a chamber-scale test that used a horizontal drift sealed with a concrete plug. In each test, the gas pressure was increased up to the onset of the measurable gas flow to obtain the maximum containment pressure. This paper discusses the hydraulic conditions for gas leakage initiation and the importance of the pore pressure measurement for monitoring the gas-tightness of the LPG storage cavern based on the test results.INTRODUCTIONJapanese first underground LPG storage plant was constructed by JOGMEC, the Japan Oil, Gas and Metals National Corporation, at Namikata in Ehime prefecture in granitic rocks (Kato et al., 2007). The “hydraulic sealing principle” (Åberg, 1977) that utilizes groundwater flow into an unlined cavern to prevent the leakage of gas through fractures in the surrounding rock mass was employed for storage of LPG. This paper describes the results of the in-situ tests performed at the Namikata Site to obtain information on fundamental gas-tightness characteristics of fractured rock. Two types of in-situ tests, a borehole gas-tightness test and a chamber gas-tightness test, were carried out near the storage caverns. Figure 1 shows the cavern layout of the Namikata underground storage plant and the test locations. The storage facilities consist of three caverns (W26m×H30m×L485m). The cavern crown lies at a depth of 150m below the sea level in Cretaceous granitic rock (Figure 1). Water curtain boreholes excavated from the water gallery tunnel at EL-125m level are located above and side of the caverns to prevent water drainage from fractures during the construction stage as well as during operation. The borehole tests were performed from a drilling adit excavated from the eastern end water gallery tunnel, while the chamber test was conducted at the southern edge of an exploratory drift extending from the central water gallery tunnel."

Jan 1, 2015