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By Fernando Canales

In the last decade a great dealt of attention has been paid to the chemistry of polynuclear gold derivatives with a central heteroatom, not only from the experimental and structural but also from the theoretical standpoint (1). Interesting hypercoordinated species of the type [C(AuPR3)5]+, [C(AuPR3)6]2+, [N(AuPR3)5]2+, [P(AuPR3)5]2+ and [P(AuPR3)6]3+ have been described (2), apart from other complexes with more conventional stoichiometry, and all have in common the presence of gold-gold interactions of ca. 3 Å. Usually, the chemistry of the first row elements of the p-block is known to follow classical rules of bonding, and only in cases of extreme electron-deficiency has the traditional electron count to be reconsidered to account for special types of molecular or solid state structures. Many of these heteroatomcentered complexes are electron-deficient and the gold-gold interactions provide a significant contribution to their stability. The attraction between these closed-shell systems has recently captured the attention in inorganic and organometallic chemistry (1). P. Pyykkö has summarized the available theoretical and experimental evidence of intra- and inter-molecular interactions between heavy metal atoms, such as Au(I) (3). In general, when heavy metals are involved in such interaction, the closed-shell attractions are of metallophilic or van der Waals type, as has been found for d8, d10 coinage-metals, and d10s2 centers. Experimental evidence for the aurophilic Au(I)???Au(I) attraction is available from crystallography, NMR and Raman spectroscopies, and optical spectroscopic measurements of the interaction strength (4). It is manifested in molecular conformations with relatively close Au???Au interactions of ca. 3 Å, whose strength has been estimated at ca. 25-50 kJ/mol (5). These attractions are weaker than most covalent or ionic bonds, but stronger than other van der Waals bonds and comparable in strength to typical hydrogen bonds. The phenomenon cannot be satisfactorily explained by classical theories such as hybridization (3). From a theoretical point of view, the attractions close to equilibrium distances are caused by dispersive interactions together with relativistic effects (6). The attractive contributions are dominated by pair-excitations from the heavy metal, such as gold, strengthened by relativistic effects. In all the cases where there are inter- or intramolecular metal-metal attractions, the correlation effects are essential; if they are omitted, at the Hartree-Fock (HF) level, repulsive interactions are obtained (6). Hence, it is necessary to use at least second-order Møller-Plesset level (MP2) methods for the dispersive forces, which are included in the electronic correlation effects (7).

Oct 1, 2003

By G. W. Neumann, J. R. Schnarr

The lead-zinc-copper-silver ores mined by Brunswick Mining and Smelting Corporation Limited at their No. 12 underground mine and No. 6 open-pit operation, and treated by distinct concentration processes in separate plants, present difficult metallurgical problems because of the extremely fine dissemination of the valuable minerals with pyrite and pyrrhotite. The problem of concentration is further complicated, in the No. 12 ore, by the presence of a varying content of graphitic carbon. This paper describes the milling of No. 12 ore and the production of copper, lead and zinc concentrates by differential flotation.

Jan 1, 1971

En quoi consistent les études de suivi des effets sur l?environnement (ESEE)? Les ESEE constituent une méthode de suivi scientifique que l?on peut employer pour déterminer la santé des écosystèmes aquatiques (qui peuvent être touchés par l?activité humaine) et l?efficacité des mesures de protection de l?environnement. Les ESEE sont des évaluations scientifiques itératives du poisson, de l?habitat du poisson et des ressources halieutiques. Le programme comporte des phases séquentielles de deux à six ans de suivi, d?interprétation et de compte rendu au cours desquelles la fréquence et le type de suivi dépendent des résultats des études précédentes. Le programme des ESEE pour les mines de métaux est fondé sur un accord conclu à l?unanimité entre les intervenants. Les exigences du programme et les guides techniques connexes ont été élaborés à la suite d?une consultation multilatérale à laquelle ont participé les représentants du secteur privé, du gouvernement et des collectivités. Toutes les mines assujetties au Règlement sur les effluents des mines de métaux (REMM), aux termes de la Loi sur les pê ches, doivent procéder à une ESEE dans le cadre de l?autorisation qu?ils ont reç ue de rejeter des effluents. Le REMM a été enregistré le 6 juin 2002 et publié dans la Partie II de la Gazette du Canada le 19 juin 2002 (SOR/DORS/2002-222).

Nov 1, 2002

By K. S. Coley, G. A. Irons, T. Kaneyasu

"It is very important to reveal the lime dissolution mechanism in steelmaking slag, to promote its dissolution without calcium fluoride, which is now almost forbidden for use in most industrialized countries. In this research, the purpose was focused on the development of an experimental method to measure the mutual diffusivity of Ca2+ under the condition of lime dissolution into slag. By forming diffusion couples using a ""vacuum slag aspirating technique"", the method was established. The following mutual diffusivities of Ca2+, in CaO-SiO2-FeO slag systems, imitating oxygen steelmaking slag, were determined using this method:4.1*10-10 m2/s at 1400°C for 27wt.%CaO-53wt.%SiO2-20wt.%FeO slag,4.3* 10-10 m2/s and at 1400°C for 20wt.%CaO-40wt.%SiO2-40wt.%FeO slag, and 1.3*10-10 m2/s at 1250°C for 20wt.%CaO-40wt.%SiO2-40wt.%FeO slag.It was also verified that, if the basicity and ferrite content of the bulk slag are low, then a calcium silicate film forms on the lime surface, and drastically deters the lime dissolution."

Jan 1, 2004

?Hydrothermal breccias-genetic models ?Deep drilling-underground potential ?Deposit variety-test new ideas Exploration Summary

May 1, 2006

By A. D. Misener, L. G. D. Thompson

"IntroductionIt was shown by work previously reported that reliable geothermal gradients representative of various regions of the earth's, surface could he obtained from extended surveys of the rock temperatures in operating mines. These surveys showed the presence of anomalies in the isothermal levels and the existence of regions of regular behaviour. Below about 3,000 feet the temperature gradients became quite regular over the areas stud1ed. It is these regular gradients which are taken as representative of the region, wherever possible.The present paper describes the extension of this work which was undertaken to obtain further temperature gradients with a view to correlating them to other geophysical properties determined for the same regions. The additional data obtained have indicated possible reasons for the temperature anomalies. The experimental procedure was similar to that already described and was again made possible through the wholehearted co-operation of the management and the assistance of the personnel of the mines concerned. The research was entirely supported by a grant from the Research Council of Ontario.The equipment was a distinct improvement over that previously used and made it possible to take many more accurate temperature readings in a given time. Thermistor resistance thermometers were used, encased in silver sheaths and protected against damage by heavy copper casings. These were calibrated with a standard platinum resistance thermometer.The bridge used with these thermometers was one of a number designed and built by the Meteorological Service and designated M.S.C. Thermometer Indicator Type C-3. This very convenient and portable instrument operated from batteries in the instrument case. Multiple thermometer connections were provided so that rapid readings• of a number of thermometers was possible to accuracy of the order of 0.1°F. All electrical connections on the panel are covered with Dow-Corning ignition compound to prevent; electrical leakage due to moisture condensation. This, together with the high resistance of the thermometers and components of the bridge, gave much more reliable results than previously obtainable."

Jan 1, 1950

By Y. Long

The deep-hole surface blasting technique is a prime method of iron ore mining. Blasting fragmentation is one of the important economic indicators that measures the blast method to obtain the iron ore. To improve the efficiency of the blasting method and further reduce the cost of the subsequent processing of iron ore, this paper summarizes measured data gained from a certain amount of blasting test conducted in an iron ore mine in Guangdong province, China. According to the data analysis, there are differences on iron ore blasting fragmentation by different indicators of deep-hole blasting, such as decoupling coefficient of charge, contact state between charge and borehole wall, and change of detonation position in charge. These factors were compared in terms of relevance and impact. Research shows: under certain rock conditions, the decoupling coefficient of the charge has a best range related to blasting fragmentation. Since the detonation position in charge determines the direction of propagation of the explosion stress wave through ore and rock, bottom initiation and mid initiation will help to improve the iron ore blasting fragmentation in joints fractured rock and ore. The research conclusions have important application value for program design of iron ore surface blasting and to guide other types of rock surface blasting.

Aug 1, 2013

By James A. Robertson

"This paper is the result of a continuing investigation begun in 1953 by government geologists and mining companies. Previous work is reviewed and the development of several stratigraphic nomenclatures and correlation schemes is traced, culminating with the interim report of the Federal-Provincial Committee on Huronian Stratigraphy formed in 1966.The stratigraphy, structure and correlation of the Huronian rocks of the Blind River area and the region between Sault Ste. Marie and Sudbury are reviewed. The area is underlain by three Precambrian units: (1) the Archean greenstones and granites, (2) the Huronian sedimentary and volcanic rocks and (3) the post-Huronian intrusive rocks. The Huronian rocks, largely quartzite and conglomerate with greywackes, argillites and carbonates, were laid down in shallow water transgressing over the eroded Archean basement. Thickness and facies changes indicate a northwesterly source, northerly overlap and deposition controlled by basement topography. Polymictic conglomerates, occurring at least at three horizons, represent tillites and are associated with varvites with dropped clasts. These are best developed in the Gowganda formation, which varies from a continental glacial environment in the north to a marine glacial environment in the southeast.There were at least three phases of post-Huronian igneous activity, probably related to several periods or phases of late Precambrian deformation and metamorphism: (1) sills of Nipissing diabase and rather younger diabase dikes; (2) the Cutler Granite and Croker Island Complex; and (3) dikes of Keweenawan olivine diabase.Copper mineralization is associated with the Nipissing diabase. The uranium ores are found in pyritic quartz-pebble conglomerate near the Huronian Archean unconformity, particularly in ancient valleys; they are considered to be placer deposits modified by later events. Uranium production from the Blind River camp to the end of 1966 was 128,160,096 pounds U308 valued at $1,203,840,848 derived from 56,077,179 tons of ore grading 0.11 per cent U308.Within the Blind River and adjacent areas, future discoveries will probably be the result of costly systematic deep-drilling programs accompanied by detailed geologic studies of the type carried out by oil companies and probably computer-oriented."

Jan 1, 1969

By R. Pelton, Z. Dai, S. Yang

ABSTRACT Hydrophobic polystyrene nanoparticles were evaluated as potential flotation collectors for pentlandite. The flotation of hydrophilic glass beads demonstrated the nanoparticles’ ability to induce flotation. Deposition of nanoparticles on glass surfaces increased the contact angle and enhanced adhesion of the beads to air bubbles. High flotation recoveries were achieved when 5–10% of the bead surfaces were covered with nanoparticles. Surface functionalization—the addition of vinylimidazole to polystyrene nanoparticle surfaces—caused the nanoparticles to selectively deposit onto pentlandite surfaces in the presence of Mg-Si slimes. Ongoing work includes attempts to identify specific applications where nanoparticle collectors might be cost effective. _ KEYWORDS Flotation, Nanoparticle collector, Coverage

Jan 1, 2014

By W. H. Patterson

The history and experience of early companies in the Islands is illustrated by the typical transactions of Trans-Western from 1959 to date. Trans-Western had entered into farmout agreements with companies strong enough to carry out at least the required minimum exploratory work and then such development as might be warranted. The farmee companies were required to make deposits to guarantee work performance during the first period of validity, i.e. the first 3 years of the 12-year life of the permits, and at the rate of 5 cents per acre. At that time, a good deal of geology was available, as a result of extensive exploration that had been carried on by the Geological Survey of Canada and other geological enterprises, with field parties travelling over and camping on all of those Islands. Trans-Western's farmees then selected, from Trans-Western's priority on 13.5 million acres, what they believed were the lands most prospective of producing large oil and gas discoveries, and, having the right to trim off acreage which they considered less prospective, thereby reducing the acreage of Trans-Western and its farmees to in excess of 5.5 million acres. The farmees then commenced a 3-year program carrying out geological exploration to the required minimum of 5 cents per acre, and with some permanent and many mobile camps.

Jan 1, 1969

By E. Allen

Quebec Cartier Mining Company operates approximately two hundred and fifty pieces of equipment in a climate with a temperature that has averaged 27.5°F during the last seven years. The use of special-purpose lubricants, fuels, antifreeze, rubber compounds, and alloy steels have reduced the cold-weather hazards. In some areas, high-cost cold-weather protective heating devices are being eliminated with experience.

Jan 1, 1966

By Dao Dac Tao

The Vietnam coal industry in recent years has achieved the rapid growth. However, in the process of industrialization and modernization of the country, the demand for coal for energy is constantly increasing. This paper presents the Vietnam coal industry in the last stage: the opportunities and challenges facing the coal industry as it strives to become modern, highly effective and capable of meeting the demands of national energy security, all in harmony with socio-economic and environmental needs.

Aug 1, 2013

By Jean-Marc Simard, Richard Genest

"La mine Agnico-Eagle, localisée près de Joutel, a été découverte en 1962 par le forage d'anomalies électromagnétiques. Exploitée à partir de 1974, elle a déjà produit près de 30 tonnes d’or à partir de 2 puits, le puits Eagle et le puits Telbel, distants de 1,3 km.Le gisement est situé entre le sommet du complexe volcanique de Joutel, à dominante felsique, et la base de l'ensemble sédimentaire de la rivière Harricana. Ces deux unités ont une extension régionale; elles sont orientées NW-SE avec une polarité NE et des pendages subverticaux. Une faille majeure, la faille Harricana, passe de façon subconcordante au contact de ces deux ensembles.La minéralisation aurifère, de 2 à 5 m d’épaisseur moyenne, est liée a une zone carbonatée, comprise entre des tufs felsiques, argilites et sédiments chimiques (éponte inferieure) et des argilites carbonatées (éponte supérieure). Le minerai est constitué habituellement de 20% de fine pyrite disséminée. L’or est en fines particules associées directement à ces grains de pyrite de texture cataclastique.Deux modelés ont été for mules jusqu' a présent pour expliquer la genèse du gisement: une thèse syngenetique (Barnett et a/.1982) et une thèse épigénétique (Wyman et al. 1986). Cette dernière apparalt comme la plus probable du fait de la présence de la minéralisation dans les zones cisaillées a carbonates secondaires et pyrite cataclastique."

Jan 1, 1990

By W. Petruk

Mineralogical studies and concentration tests were conducted on samples from an oolitic iron deposit from the Peace River district in Alberta to determine what concentrate grades and metal recoveries could be obtained. The samples assayed 32 to 37 wt. % Fe, and consisted of goethite, nontronite, ferruginous opal, siderite , quartz, amorphous phosphate and illite . Flotation with fatty acids yielded the best over-all results. A flotation concentrate from a composite sample of the iron horizon assayed, by weight, 43.0% Fe, 12.3% SiO2 , 1.9% CaD, 0.9% MgO, 4.5% Al2O3 and 2.0% P2O5 and lost 17.2% on ignition, for an iron recovery of 48.8% and a silica rejection of 80%. When heated to drive off the water, the concentrate assayed 52 w t. % Fe and 14. 8% w t. % SiO2

Jan 1, 1977

By Paul Bedard, Réal Daigneault, Guy Perrault

"La mine Lamaque est située a Val d'Or, Québec; les roches hônes appartiennent au groupe de Malartic, partie supérieure, et sont des andésites et des pyroclastites. On y retrouve deux formes d'intrusifs; des petites cheminées (ca. 150 m D) et des dykes (ca. 10 m d'epaisseur). Les petit es cheminées contiennent:1 - des diorites et des tonalites (cheminées principale, est et ouest) d'affinité calco-alcaline: Zr 140 ppm, Sr 761 ppm, P2O5 0.31% et (La/Sm)n 3.0;2 - des diorites (cheminée 4) d'affinités tholéiitique: Zr 32 ppm, Sr 181 ppm, P2O5 0.27% et (La/SM)n 1.5.La diorite de la cheminée no 5 contient deux fractions, une de chacune de ces deux affinités. Les dykes tant de porphyre feldspathique quartzifére que ceux de prophyre feldspathique sont d'affinité calco-alcaline: Zr 83 ppm, Sr 500 ppm et P2O5j 0.10%.Le gisement de 10 mine 2 est filonien: veines subhorizontales (""flats "") surtout et veines sub-verticales dans des zones de cisaillement. Le dernier réajustement structural de direction de compression nord-sud a broyé le quartz des veines existant es et rendu possible leur minéralisation. Les veines minéralisées contiennent du quartz, de la tourmaline, de la calcite avec des traces de scheelite, de pyrite et d'or; elles sont bordées par de minces (2 à 20 cm) bordures d'altération où l'on retrouve un enrichissement en carbonate, paragonite, apatite, rutile, saphène et zircon et où les phases ferromagnésiennes sont disparues. On a documenté le migrations géochimiques suivantes:I - de la bordure d'altération vers l'éponte, K2O, Rb et MgO;2 - de l'éponte vers la bordure d'altération, Na2O;3 - de l'éponte vers la veine, SiO2.P2O5, TiO2, Zr, Y, Nb et CaO sont enrichis dans la bordure d'altération."

Jan 1, 1983

By Patrick Wong, Gareth Hatch, M. A. Halim, V. I. Lakshmanan, Darcy Tait

"This paper describes development of an integrated chloride process for separation and purification of REEs. The process includes atmospheric leaching of ore/concentrate with mixed chloride lixiviant containing HCl and MgCl2 followed by bulk recovery of REEs, dissolution of the bulk intermediate product, and separation of individual REEs by solvent extraction (SX) process steps. Mixed chloride leaching technology provides the opportunity to regenerate the lixiviant, while the addition of MgCl2 in HCl enhances the hydrogen ion activity by orders of magnitude increasing REE extraction efficiency at a lower concentration of HCl. An individual REE separation process developed by Innovation Metals Corp. is being piloted at a state-of-the-art facility at Process Research ORTECH Inc. in Mississauga, Ontario, Canada. The SX process includes the separation of light REEs (La – Nd), medium REEs (Sm – Gd) and heavy REEs (Tb – Lu plus Y) from leach liquor followed by individual REE separation. Each SX circuit proceeds by multistage extraction followed by scrubbing and stripping. The process is chloride based and reagents are recycled, reducing waste generation and optimizing water usage to reduce environmental impact.INTRODUCTIONRare earth elements (La to Lu plus Y) exhibit a range of unique magnetic, electronic, catalytic and optical properties. Due to these special properties, the application of REEs is increasing and they are found in components for wind power generation, hybrid electric cars, catalytic converters, and many electronic devices.Rare earth elements (REEs) are commonly divided in two groups: light rare earth elements (LREEs) and heavy rare earth elements (HREEs). Light rare earth elements include elements from lanthanum (La) to neodymium (Nd). Although promethium (Pm) is considered an LREE it is unstable and scarcely occurs in nature and is generally excluded. Heavy rare earth elements include elements from samarium (Sm) to lutetium (Lu) plus yttrium. Although rare earth elements are not rare and the rare earth oxides are scattered around the globe, over 95% of REEs+Y are currently produced in China (Pitts, 2011). On one hand the Chinese government is restricting the export of rare earth elements and on the other hand the demand for REEs+Y is increasing in the rest of the world. This has created an imbalance in the supply and demand of rare earth elements and has led to a rush for developing new rare earth projects."

Jan 1, 2016

By David Morrison

Our present longwall problems in Cape Breton can be grouped under five main classifications. These are: (1) Roof control on the face and on the main roadways leading thereto. (2) Transportation of coal along face and levels. (3) Mechanical loading at the face. (4) Safe method of conducting and applying power at the working faces. (5) Dust nuisance. The usual layout for longwall operation in Cape Breton is to have three, and sometimes four, faces in line with each other, the length of face being from 400 feet to 500 feet (see Figure 1), and producing between 425 and 500 tons per face. Each wall is serviced by a well constructed roadway for transportation of coal, men, and materials, and is operated as an independent unit. Each wall works under a regular cycle of operations: first, cutting and boring; second, drawing hardwood chocks, building midwalls, and shifting panlines; and third, loading. The present method of roof control and operation of longwall faces has developed through trial and error since the commencement of longwall miring in Cape Breton. The basic method of roof control in all longwalls in Cape Breton is: rigid support of the roof in the immediate vicinity of the working faces by hardwood blocks, as shown in Figure 2, accompanied by a cushion support furnished by continuous midwalls, 12 feet wide, constructed of stone obtained from the waste and spaced at 50-foot centres. These midwalls are kept forward to within 4 feet to 10 feet of the working face and allow a gradual subsidence of overhead strata, thus preventing any sudden break at the working face.

Jan 1, 1947

By Raymond D. Potts

"Minntac is a taconite mining, concentrating and pelletizing operation located near the town of Mountain Iron, Minnesota, U.S.A. It is totally owned and operated by USX Corporation and represents its largest source of domestic iron units. Minntac began producing fluxed pellets in 1988 and has produced both acid and fluxed pellets since then. This paper compares the acid and fluxed pellets produced at Minntac. It reviews modifications that have been made to the plant flowsheet and discusses areas recognized for improvement since the beginning of fluxed pellet production. It also comments briefly on the performance of Minntac fluxed pellets in USX blast furnaces and the future of fluxed pellets at Minntac.IntroductionMinntac was built in three steps with each step designed to produce 6 million long tons of acid pellets per year. The actual production has varied though. Figure I shows the production by year at Mirmtac. Step I began production in 1967, Step 2 in 1972 and Step 3 in 1978. Mirmtac produced 16.5 million tons in 1979 but only 3.5 million tons in 1982 when the facility was shut down for six months because of the lack of demand for pellets. Since the initial start up, Mirmtac has produced over 200 million long tons of pellets. Until 1987, all the pellets produced were ""acid"" pellets. In 1987, equipment to produce ""fluxed"" pellets was installed and tested. In 1988, full scale production of fluxed pellets began."

Jan 1, 1991

By J. Gebhardt, D. McBride, C. R. Bennett, Croft. N., M. Cross

A comprehensive model of solution flow through heap leach systems requires a numerical solution with the ability to predict variably saturated-unsaturated flow through porous media domains that contain materials with spatially variable properties. The types of flow associated with stockpile leach processes lead to flow problems, such as infiltration into dry soil, drainage, perched water tables and flow through heterogeneous materials. Computational methods for modelling this class of flow behaviour are conventionally based on the classical Richards' equation. However, the governing equations are highly non-linear, difficult to solve, and require iterative numerical solution methods. The pressure-based form of the Richards' equation suffers from poor mass balance, while the mixed form can possess convergence difficulties. An adaptive transformed mixed algorithm is described, which reduces the non-linearity of the problem, optimizes the time step size, and provides a fast, numerically robust scheme that significantly reduces computation (or CPU) time. This method is shown to give fast, accurate solutions on a number of complex flow problems. The utility of this algorithm is illustrated through its implementation within the PHYSICA computational modelling software, which incidentally, provides a framework for a comprehensive heap leach model.

Jan 1, 2005

By W. A. Jones

"The Hollinger gold mine is in the Porcupine area, Cochrane district, in northern Ontario. The adjacent town of Timmins, which has a population of 25,856, lies 490 miles by railway north of the city of Toronto.The property was staked in the late summer of 1909. The original four claims were staked by Benjamin Hollinger, after whom the mine was named. Development commenced in the autumn of 1909 and mill construction in the winter of 1910. A catastrophic forest fire swept the district in 19ll, destroying the surface plant, so that the original 300-ton mill was not completed until June 1912. From that date up to December 31, 1945, 44,280,750 tons of ore have yielded 13,636,796 oz. gold and 2,613,354 oz. silver. The total value of the production has been $363,638,315.0REBODIES AND MINERALIZATIONThe orebodies consist of quartz veins, stringer lodes, and scockworks, with associated pyritized wall-rocks. The width of individual orebodies, as exposed by mining operations, ranges from 1 to 70 feet and averaged approximately 10 feet in 1942. The vein system forms a complex pattern in a favourable zone, which in places is 6,000 feet long and 4,000 feet wide. The deepest level being developed is 5,150 feet below the surface. Few veins are persistent for long distances, although some are continuous for more than 1,000 feet longitudinally and vertically.The host rocks consist of a closely folded series of Precambrian lava flows of Keewatin age. These are schistose and hydrothermally altered, but are believed to have originally been of intermediate to basic composition. The schistosity strikes N.70°E. and dips to the south at 75° to 80°. The structure of the formations is complex, but in the principal ore-bearing zone the general dip of the flows is to the south at a slightly flatter attitude than the schistosity."

Jan 1, 1954