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By N. E. Chaouai, M. Lavigne

"Indicator kriging is one of the non-parametric geostatistical techniques, ideal for estimating the reserves of irregular mineralizations (e.g. gold, uranium, platinum, diamonds, etc.). Such mineralizations are characterized by variograms which are very sensitive to extreme values (outliers) and very difficult to model.The classical approach to this problem in the industry is to trim off these high grades using arbitrary empirical upper limits established either from practice or subjectively. Contrary to this simplistic approach, indicator kriging discretizes the histogram of the grades (usually log normal) in several classes and carries out interpolation separately for each class. This paper gives an overview of the differences between ordinary and indicator kriging along with the steps required to carry out indicator kriging. The paper concludes with a case study involving a gold deposit estimation.IntroductionParametric geostatistics (ordinary kriging) has given us satisfactory results over the years in estimating the reserves of well behaved deposits with coefficients of variation close to 1 (e.g. sedimentary and porphyry type deposits). However, numerous problems have been encountered in estimating irregular mineralizations (e.g. small vein deposits of precious metals) with high coefficients of variation in the range of 2 to 5. Such deposits are characterized by a very small proportion of extreme values (outliers) which create distortions on the variograms (pure nugget effect) and render them useless(1,2).The solution often followed by the mining industry today is to trim off these values based on empirical limits. These limits are derived either by comparison with production results (or bulk samples) or by geological interpretations. Needless to say that such manipulations can lead to serious errors in estimating ore reserves (usually underestimation of total metal quantity), especially when production results or bulk samples are absent.On the other hand, the solution followed by the geostatisticians in the past was to smooth out the data using transforms (e.g. normal-score or natural logarithms). Such transforms are nonlinear and they required non-linear estimation techniques such as disjunctive kriging (DK) or multivariate gaussian kriging (MG) which require normal related hypotheses, not necessarily true in geology.Nonparametric geostatistics (indicator and probability kriging) have been -developed in order to handle these problems related to highly skewed distributions."

Jan 1, 1990

By Ferri P. Hassani, Riadh Bouzaïene

"Selected methods of pressure loss predictions in horizontal slurry flow in pipelines are presented. For a given combination of flow velocity, solids concentration and particle size, the slurry and its flow conditions are described, and an appropriate method of pressure loss prediction is outlined. The wide range of conditions treated in this paper may be found in practice in areas varying from the hydraulic transport of low concentration slurries to dense-phase conveying of paste backfill in underground mines.IntroductionThe hydraulic conveying of solid particles in pipelines is a major component of the mining and mineral processing industry. Whether the objective is to transport ore to the processing plant or to make use of mill tailing as backfill material; the need for well designed, economical hydraulic conveying systems is recognized.The contribution of this paper is part of an on-going research program at McGill University involved in optimizing and developing techniques for total mine waste disposal. One of the main concerns in the conveying of solid-liquid mixtures is the prior knowledge of the pumping power input required. This energy requirement is directly proportional to the pressure losses incurred in the pipeline system. Understanding the sources of such pressure losses and predicting their magnitudes should enable the system designer to make informed decisions regarding the optimum mode of hydraulic transportation commensurate with the over-all requirements of the operation.This paper is an attempt to classify pressure loss prediction methods encountered in the literature for solid-liquid mixtures. In spite of the large number of publications spanning thirty years of research in the field of slurry transportation, it is sometimes difficult to correctly identify the appropriate methods applicable to a given situation. This is partly due to the inherent complexity of the mechanics of slurry flow and the ensuing uncertainty about the nature of the flow regime under investigation.Our approach is to use three fundamental parameters, namely: flow velocity, solids concentration and particle size (for solid particles with a given density) to characterize the slurry and the flow conditions, and to match them with an adequate pressure loss prediction method. For each combination of flow velocity, solids concentration and particle size, a description of the most likely prevalent flow conditions and some known methods of dealing with them will be presented. Qualitative definitions of ""high"" and ""low"" magnitudes of the aforementioned parameters will be given as a general guide to the classification scheme presented in this paper."

Jan 1, 1992

By John De La Vergne, Morri Medd

"This paper describes the sinking of a circular concrete ventilation shaft through 110feet of water-bearing overburden. The brine circulation freezing method was used to stabilize the walls during excavation. In order to take advantage of the cold winter weather, a custom-built heat exchanger (natural radiator) was installed in place of the standard mechanical refrigeration plant.IntroductionIn the late fall of 1979, Les Mines Selbaie awarded a contract to the firm of 1.S. Redpath Limited to sink a ventilation shaft on its property in northwestern Quebec. The shaft was to be sunk through 110 feet of water-bearing overburden and approximately 90 feet of rock to a final depth of 200 feet below surface. The water table was measured at 16 feet below the surface elevation.After examining the soils report and diamond drill core from the shaft area, Redpath came to the conclusion that freezing was the best way to stabilize the overburden for sinking. LocationThe mine site is 420 statute miles due north of Toronto, just east of the Ontario/Quebec border (Fig. 1). Access to the site is provided by a development road built by the Quebec government from the Matagami/lames Bay Highway. History of Ground Freezing In the Mining IndustryIn 1862, shortly after the development of mechanical refrigeration, a mine shaft was sunk through an artificially frozen water-bearing formation in the United Kingdom. The first application of ground freezing in North America was for a Michigan iron ore shaft in 1888. Since that time, the freezing method has been used to sink hundreds of shafts throughout the world. Its best known application was to sink sixteen shafts through the Blairmore Formation in Saskatchewan.The same method has been used in every case. It involves chilling a calcium chloride brine solution and circulating the brine in concentric pipes, spaced between 3 and 6 feet around the shaft perimeter and usually 4 to 5 feet from the limits of the proposed shaft excavation."

Jan 1, 1982

By Kurt D. Mitchell

"This paper discusses general application for A C variable frequency drives in the mining industry. A review of induction motors characteristics, adjustable frequency controller fundamentals, and three commonly used controllers is presented. General application guidelines for the three different types of controllers; variable voltage input , current source input and pulse width modulated are then reviewed in detail, and an example of the economic benefit of this technology is discussed. IntroductionSoon after static DC variable speed drives were well established in industry, a need for static AC variable speed drives was seen. The first technical papers describing possible systems appeared in the mid-1960s, with commercially available units arriving in the early 1970s. Without exception, static AC drives are substantially more complex than their DC counterparts, but they have some very desirable properties. As compared to DC motors, AC motors are less costly, physically smaller, more reliable, require less maintenance , easily sealed, have good load regulation, are able to run at higher operating voltages, and have little danger of over-speed runaway . These properties are particularly desirable in explosion-proof, submersible or difficult accessibility applications.Variable speed AC drives are now a proven technology. available in packages from Sub-horsepower to hundreds of horsepower, from 115VAC to 4160 VAC. This paper covers the principles of operation of three common types of controllers, application criteria, motor consideration and finally an example of how an AC variable speed drive can pay for itself in terms of energy savings."

Jan 1, 1986

By K. Enns, J. J. Byerley

"While thiocyanate (SCN-) is used in a number of industrial processes (production of polyacrylonitrile filaments, synthesis of agricultural chemicals and certain metallurgical solvent extraction and flotation circuits) it is recognized more as an undesirable by-product associated with ' the metallurgical industry. Thiocyanate is present at low concentrations in some waste streams from the iron and steel industry. Of particular significance is the formation of thiocyanate during cyanidation of gold and silver ores, concentrates, tailing s and residues. The thiocyanate levels present in the resulting effluents may range from a few mg/I to several thousand mg/I.At present, thiocyanate does not appear to be as hazardous in the environment as cyanide (CN-) at the same concentration although its interaction with other species and resulting decomposition of products may be unacceptable. Of course the presence of thiocyanate in the leaching circuit and ultimately in the effluent streams may add considerably to the oxidative requirments of any non-selective treatment process for cyanidation wastes.With respect to the thiocyanate as it relates to the cyanidation process, two aspects are evident. Thiocyanate forms and persists in the cyanidation circuit resulting in a ""fouling"" condition with subsequent loss of leaching activity. In order to reduce or control this problem, it is common practice for some mills to discharge daily as much as 20% of the barren leach liquor. Besides contributing to fouling of the leach liquor the formation of thiocyanate represents an irreversible loss of reagent cyanide. It is noteworthy that in some present or proposed mill practice reagent cyanide loss through thiocyanate formation may reach 50%(1). The purpose of this paper is to discus s the application of controlled electrooxidation of thiocyanate with the view of suggesting a process for regenerating cyanide from waste thiocyanate(2). The paper describes the important theoretical aspects and presents experimental data obtained for thiocyanate electrooxidation using both small and large scale electrochemical reactors. Some economic conclusions are presented."

Jan 1, 1984

By J. Béland, C. Giguère

"The auriferous mineralization at the Sigma-2 gold mine occurs in quartz-carbonate-tourmaline veins emplaced in a fractured granaphyre layer in the upper part of a differentiated gabbro-diorite sill. Kinematic indicators show that fracture planes were active as strike slip, dip-slip (reverse) and tensional faults.Measurements of attitudes of fractures and movement vectors indicate eight different sets that can be grouped into three systems: (I) an east-west oriented system includes a subvertical set and two other sets dipping north and south respectively; (2) a subhorizontal system of two conjugate sets bisected by a third tensional set; and (3)a system of sub vertical conjugate northeast and north-northwest trending sets.Kinematic analysis indicates that the subvertical set of the east west system was subjected to dextral strike-slip movement activated by a northwest-southeast compressive stress whereas the bulk deformation resulting from the remaining and subsequent seven sets can be explained by a protracted subhorizontal north-south compressive stress.The valuable gold mineralization is found principally in the fracture-filling veins of the subhorizontal system and subordinately in the other sets; among these other sets, the NE trending subvertical one is slightly more favourable.The over-all tectonic picture is that of an early mild dextral strike slip faulting in a ductile-brittle medium followed by a general flattening involving, first, a vertical and, later, a lateral extension by fracturing in a medium that had become brittle.The structural features are such that the differentiated sill could not be the source of the auriferous hydrothermal solutions."

Jan 1, 1990

By A. B. Luz, A. Middea

Kaolin clay is heavily used in the paper industry as a coating and a filler, however to attend the specifications required by the industry it has to be processed. Kaolin is also used as a filler and pigment in various materials, such as paint, plastic, rubber etc. Some crude kaolins as mined in Northern Brazil, contain colored impurities such as iron oxide and rutile/anatase. These minerals normally are stained by iron and as a result vary from yellow to dark brown in color. The kaolin beneficiation process used in that region consists mainly of degritting, fractionation by centrifuge, high gradient magnetic separation, bleaching with sodium dithionite, filtering and drying. In some kaolin clays from that region, titanium oxide mineral occurs in fine fraction, lower than 2 µm, and so making the industrial process more difficult. The conventional method of classification and bleaching with sodium dithionite, markedly improves kaolin brightness, but has little effect on anatase removal. In fact, the fine fractions resulting from centrifugation, in many cases contain more TiO2 minerals than the original whole clay or the coarse fraction. The present work is related to purification of Brasilian kaolin clay using selective flocculation for removing its colored impurities such as rutile and anatase. This study was conducted in bench scale and it consisted of: blunging, screening, conditioning and decantation. Overflow and underflow resulting from settling of the flocculated material were then dried and submitted to TiO2 and brightness analyses. Sodium polyacrylate and sodium silicate were added to kaolin clay suspension as dispersant and ammonium hydroxide was also added to adjust pH. After degritting, the minus 44 µm fraction was conditioned with hydroxamate surfactant and then polymers of different anionic charge were added. The influence of pH and type of polymer on efficiency of TiO2 removal, as well as kaolin mass recovery were studied. The results obtained in the present study are quite promising. It was possible to diminish TiO2 content and increase kaolin brightness (ISO) from 82 to 88%.

Jan 1, 2004

By D. Raicevic

After more than 93% of the uranium is extracted from Elliot Lake uranium ores by a sulphuric acid leaching process, the leach residue (tailings) contains small amounts of uranium and radioactive isotopes, particularly radium-226, which is the most serious health hazard. Heavy metal components and pyrite are also present, along with the gangue minerals. Currently, over /000 acres of the Elliot Lake area are covered with these tailings, which contain over five million tons of pyrite. Because of constant oxidation of the pyrite by bacteria (thiobacillus) and the presence of moisture, pyrite slowly generates sulphuric acid, which steadily leaches the metal-bearing constituents from the tailings. The seepage-flows of the dissolved contaminants, although often quite low in volume, have an environmental impact on the Elliot Lake area. Although these seepages are treated and most of the contaminants removed and impounded, a small amount of the radioactive contaminants reaches Lake Huron via the Serpent River. This paper describes a flotation approach for treatment of the Elliot Lake uranium tailings to produce new, decontaminated tailings practically free of pyrite, with radium, thorium and uranium contents considerably reduced. The decontaminated tailing produced, which comprises about 75% by weight of the current uranium tailings, appears to be suitable for mine backfill. Because mine backfilling normally uses about 50% of the plant tailings, the surface storage of about half of the uranium tailings, therefore, would be eliminated by this process. Mine backfilling would also increase the mine production and thus enlarge the over-all uranium resources due to recovery of the ore from pillars. The pyrite concentrate produced from the current uranium tailings would be suitable for sulphuric acid production. The possibility of uranium recovery, and disposal of radium and thorium from the concentrates produced, is now being studied at CANMET.

Jan 1, 1979

By G. M. Ritcey, K. E. Haque

"Laboratory-scale sulphuric acid leach tests were conducted on Elliot Lake and Rabbit Lake ores in the presence of various oxidants, namely: Fe2(SO4)3, CI2, H2O2, NaClO3, MnO2, H2SO5, HNO3, Oxon e, K2Cr2O7, KMnO4, O3 and O2. Uranium extraction is significantly accelerated when an oxidant is present in the leach slurry. Uranium extraction of 96-99% can be achieved by maintaining the oxidation potential of the leach slurry in the range of400 to 500 m V (S.H.E.). A rough cost comparison of all the oxidant s indicates that the use of Fe2(SO4)3, 02, O3, C12, HNO3 or MnO2 is far less expensive than NaClO3 and the uranium extraction rates are similar to or better than with NaCIO3. For uranium extraction, it is concluded that gaseous oxygen (i.e., air or oxygen) would be the most effective and economical oxidant for the 24- to 36-hour leach of Elliot Lake ore; whereas for the 8- to I2-hour leach of Rabbit Lake ore, a strong chemical oxidant (e.g. NaCIO3, H202, 03, K2Cr2O7, H2SO5 or HNO3) would be a logical choice.IntroductionThe common practice for the treatment of uranium o res is leaching with sulphuric acid or with a carbonate-bicarbonate mixture. Generally, the latter process is ad opted when an excess (> 18%) of acid-consuming components (e.g., carbonate) is present in the ore. Irrespective of the nature of the leachant, the addition of an oxidant to the leach mixture is necessary to obtain a high uranium extraction.The maximum extraction of uranium can only take place when all the uranium is in the highest oxidation state (i.e.,U +6-uranic ion) . Because a certain percentage of uranium present in the ore is invariably in the lower oxidation state (i.e.,U+4-uranous ion) , the addition of an oxidant to the leach slurry is necessary to oxidize uranous ion to the uranic state."

Jan 1, 1982

By J. G. Schofield, R. C. Francki, K. M. Donaldson, F. E. Ham

"Developments in pyrometallurgical technology have led to larger furnaces operating under more intense process conditions. In order to maintain the reliability of these furnaces, which are frequently single-line units, the design of the refractories, cooling systems and bindings has become more critical. Traditional thermal and chemical requirements for the refractory to resist slag attack must still be carefully determined. The larger, modem furnaces have placed a new emphasis on the structural properties of the refractories as well as their thermal properties to suit the extensive cooling systems. Based on operating experience, supported by computer models, the refractories and bindings are designed to work together to accommodate the thermal expansions and contractions in order to minimize permanent furnace growth and the risks of leaks. IntroductionElectric furnaces are used extensively in smelting copper and nickel ores and concentrates. Laterite nickel ores and high-magnesia copper, nickel and platinum sulphide concentrates are smelted virtually exclusively in electric furnaces to accommodate the high melting point of the slags produced. Although a number of smelting processes using oxygen-enriched and/or preheated air have been developed to replace reverberatory furnace smelting of conventional copper and copper-nickel concentrates, (lnco, Noranda, Outokumpu, Mitsubishi) electric matte furnaces remain a strong process alternative for these concentrates, either as the primary smelting vessel or for cleaning the slags produced from these processes.The development of large, high-powered furnaces has been an important factor in the growth of electric smelting technology, as evidenced by the list of operating matte and ferronickel furnaces shown in Table I. Because the compressive forces required to maintain a tight, leak-free furnace increase with furnace dimensions, the selection and design of the furnace refractories, cooling systems and bindings require increased attention."

Jan 1, 1993

By Tim J. Carew, Dennis C. Martin

"One approach to stabilization of rock slopes is to place a buttress at the toe of the slope to provide additional resisting forces and increase the length and strength properties along the failure surface. This paper describes the rock mechanics and mine planning aspects of incorporating a buttress of intact rock in the lower part of the slope as part of the slope design for the south wall of the final pit at Cassiar Mine. Stability analysis techniques and results are described. Analyses results have indicated that, in order to maintain steep over-all slopes in the final pit, a buttress of intact rock shoud be incorporated into the lower section of the slope until late in mine life. The effect of the buttress is to flatten the slope and reduce the slope height thereby improving slope stability. The mining plans would be such that the buttress would be mined out during the last four months of mining when the consequences of instability would be least severe.IntroductionThe concept of using a buttress to stabilize slopes has been used in mining and civil engineering construction in may locations (Richards and Stimpson, 1977). Most buttresses involve placement of coarse rock fill timber cribs or other material as a load at the toe of an already unstable slope to provide forces which resist failure by counteracting driving forces and increasing the length and strength of the failure path.This paper describes the geotechnical and mine planning aspects of incorporating a buttress of intact rock in the design of the south wall of Cassiar Mine. The effect of an intact rock buttress is to flatten the slope and reduce the slope height, thereby improving slope stability. No actual construction is required other than normal excavation of the slope. The ""mine plans would be such that the buttress would be mined out at the end of mine life when the impact of instability would be less severe and additional ore might possibly be recovered from the slopes. Mining of the buttress could induce instability at the very end of mine life at a time when maximum ore extraction has been achieved."

Jan 1, 1986

By P. R. A. Andrews, I. Jackman

"A mineral processing investigation to recover chromite was performed at Lakefield Research, under the guidance of CANMET personnel, on a 70 tonne ore sample from the Bird River deposit in Manitoba. In the laboratory phase a flowsheet was developed which involved grinding, gravity separation and flotation. The gravity concentrates were upgraded by magnetic separation and the flotation concentrates by gravity concentration . Pre-concentration by electronic ore sorting, magnetic separation and heavy media separation also was examined.The developed flowsheet was applied on a pilot-plant scale in the second phase of the testwork to the ore as received, and to ore pre-concentrated by electronic ore sorting and magnetic separation. Ore pre-concentrated by heavy-media separation was treated on a laboratory scale based on the pilot-plant flowsheet ,Processing the are as received resulted I n 77% recovery of chromite in a concentrate analyzing 30% Cr20 J; processing are pre-concentrated by electronic are sorting resulted in 64% recovery of chromite in a concentrate analyzing 30.5% Cr20J."

Jan 1, 1988

By Pierre Giasson

"Les avantages de l'électricitéLe thème de la réunion 1982 de l'ICM District No. 2: "" Le défi des années 80 pour l'industrie minière de la Côte-Nord"" exprime trè s bien la réalité . En effet, la récession économique qui touche présentement tout le monde industrialisé, frappe de façon particulièrement sévère le marché du fer et de l'acier. Il est donc primordial pour les industries minières de la CôteNord de minimiser leurs coûts de production. Comme on sait, une bonne part des coûts de production est directement reliée à la consommation d'énergie.Si on retourne en arrière de quelques années, les prix des produits pétroliers étaient beaucoup moins élevé s que maintenant . Par exemple: A Philadelphie, en janvier 1930, le prix de l'huile no. 6 (bunker C) était de 1.22$ le baril. En 1940, le prix mondial du pétrole brut se situait aux environs de 1.80$ le baril et augmentait très lentement jusqu'en 1973. A la mi-octobre 1973, l'organisation des pays exportateurs de pétrole (O.P.E.P.) surprend le reste du monde en annonçant que le prix du brut grimpe à S.12$ le baril. .. on connaît la suite.On sait qu'au point de vue énergétique, le nord du Québec est l'une des régions les plus avantagées au monde. Malgré le fait que notre climat soit plutôt défavorable, nous sommes assurés d'une alimentation électrique à toute fin pratique éternelle, contrairement aux autres régions du globe. En effet, l' hydro-électricité ne représente que 2.S070 de toute l'électricité produite dans le monde.Une bonne partie de l'énergie consommée dans les industries minières de la Côte-Nord est utilisée pour produire la vapeur. Or, il y a plusieurs avantages à produire de la vapeur à partir de l'électricité:1. Le prix d'achat d'une chaudière électrique peut être moins de la moitié de celui d'une chaudière à carburant fo ssile.2. Le prix de l'électricité est plus bas que celu i des autres sources d'énergie disponibles dans notre région.3. Hydro-Québec offre un programme spéci al de subventions et un prix garanti de l'électricité, inférieur de 10070 à celui de tout autre combustible (1982).4. Souvent il est possible d'utiliser l'énergie hors pointe à un coût minime.S. L'espace requis pour un chaudière électrique est beaucoup moindre. Par exemple: une chaudière d'une capacité de 120000 Ibs/hre ne demande que SO pi? de plancher, c'est-à-dire un cercle de 8 pieds de diamètre comparativement à environ 600 à 700 pi2 pour une chaudière au ma zout.6. Aucun espace n'est requis pour l'entreposage du carburant.7. Aucun espace n'est requis pour la cheminée.8. Il n' y a que très peu de pièce s mécaniques, donc ces chaudières demandent très peu d 'entretien .9. Les chaudières électriques ne génèrent aucune pollution, donc on n'a pas besoin d'équipement coûteux de contrôle de la pollution.10. Ces chaudières sont extrêmement rapides. En effet, on peut passer de zéro à la production maximum en moins d'une heure si la chaudière est froide et en quelques secondes seulement si la chaudière est à sa température d'opération.11. L'efficacité de ces appareils est au moins de 9S% par rapport à 80-8S% pour les chaudières au ma zout. De plus, cette efficacité demeure la même quel que soit le niveau de production de la chaudière. Il faut faire attention ici: les manufacturiers proposent des rendements de 99% et plus, mais ceci ne tient compte que des pertes de chaleur à travers l'enveloppe, et de l'énergie nécessaire au fonctionnement de la pompe de circulation. Il faut ajouter à cela l'énergie perdue à cause de la vidange qui varie selon le type de chaudière et selon la qualité de l'eau d'alimentation.12. Ajoutons simplement que ces appareils sont très facile à opérer du fait qu'il n'y a aucun système complexe à manipuler.Cependant, il y a un inconvénient non négligeable à utiliser l'électricité comme source d'énergie: comme on ne peut pas emmagasiner l'énergie électrique, nous sommes à la merci du fournisseur."

Jan 1, 1985

By C. A. Godden, T. N. Atkinson

Metallographic techniques developed from studies of corrosion films and electroplated coatings on aluminum alloys, are discussed. These methods, the result of work at the Naval Research Establishment, give extremely flat fields at the interface despite the large difference in hardness, in cases where electrolytic polishing could not be used. Techniques to overcome the similarity in refractive index of immersion oil, aluminum ox1d~, and mounting plastic are also considered, as are methods for improving visual and photographic contrast in areas of interest. A device for marking specimens is also de-scribed. ELE•CTROLYTIC polishing is inapplicable in the study of surface films on aluminum, whether corrosion films or electrodeposits. Mechanical procedures must there-fore be followed. Sample flatness and edge retention are of paramount importance. Special measures are required in the study of oxide films, because of the close proximity of the refractive indices of aluminum oxide, mounting plastic, and immersion oil.

Jan 1, 1962

By P. R. A. Andrews, I. Jackman

"A mineral processing investigation to recover chromite was performed at Lakefield Research, under the guidance of CANMET personnel, on a 70 tonne ore sample from the Bird River deposit in Manitoba. In the laboratory phase a flowsheet was developed which involved grinding, gravity separation and flotation. The gravity concentrates were upgraded by magnetic separation and the flotation concentrates by gravity concentration. Pre-concentration by electronic ore sorting, magnetic separation and heavy media separation also was examined.The developed flowsheet was applied on a pilot-plant scale in the second phase of the testwork to the ore as received, and to ore pre-concentrated by electronic ore sorting and magnetic separation. Ore pre-concentrated by heavy-media separation was treated on a laboratory scale based on the pilot-plant flowsheet.Processing the are as received resulted in 77% recovery of chromite in a concentrate analyzing 30% Cr20 J; processing are pre-concentrated by electronic are sorting resulted in 64% recovery of chromite in a concentrate analyzing 30.5% Cr20J.IntroductionA five-year mineral development sub-agreement was signed between the federal government and the province of Manitoba in 1984. The purpose of the agreement was to establish a work program which would strengthen and diversify the mineral resource industry of Manitoba. Basically, the agreement covers three sectors: Sector A, geoscience; Sector B, mining and minerals technology research; and Sector C, development studies.Project selection involved input from industry, federal and provincial representatives. In the case of industrial mineral s, the selection was initiated at a meeting held at the offices of the Department of Mines and Energy, Winnipeg, Manitoba, in October 1985. One such project was the evaluation of the chromite ore deposits at Bird River, Manitoba."

Jan 1, 1988

By M. R. Shadnam

This contribution provides an assessment of research and development efforts to optimize SOx, NOx and mercury capture in flue gas. Coa, characteristics and combustion conditions in a power plant have an impact on the types and concentration of flue gas pollutants. These factors can also affect the amount of pollutant removed. This contribution would also provide a comparative study of the technologies that holistically aim remova, of SOx, NOx and mercury altogether in coal-fired power plants. A portion of this contribution provides background information on regulatory drivers.

Jan 1, 2010

By S. C. Tadolini

"Roof bolts are the primary means of roof support in underground mines in the United States. Presently, post installation loads are measured on about 10% of the expansion anchor and combination bolts by using standard torque wrenches that Unit the accuracy of the measurements to about ±30%. No system has been available for measuring the loads generated on full-column resin grouted bolts. Mine roof bolts are long, slender, non-uniformly sized, roughly forged, and placed in a corrosive environment, creating obstacles for researchers trying to utilize ultrasonic reflection techniques to measure strain. A complete measurement system has now been developed by the U.S. Bureau of Mines, Denver Research Center. This system is being used successfully in determining loads measured on expansion anchor and combination bolting systems, examining the transfer mechanics of full-column, resin-grouted bolts, and measuring loads generated on bolts in an underground roadway support system.IntroductionMillions of roof bolts are used each year to provide structural support in underground U.S. metal, non-metal, and coal mines. Approximately 45% of the bolts used are expansion anchor, 45% are resin-assisted combination or full-column resin-grouted, and 10% are friction anchored. The effectiveness of these bolting types is dependent on a number of factors including rock density, bolt length, in situ stresses, rock properties, bolt pattern, installation tension, etc. When implementing expansion anchor and resin assisted combination bolts , installation and post-installation tension, or load, is a major determinant of support quality and subsequent behaviour of the reinforced roof. The method by which these systems carry roof loads is well understood and documented(1,2).The importance of these installation and long-term bolt tension measurements is well recognized and are required in the federal government regulations(3). A statistical sample of the bolts, lout of 4 during installation and lout of 10 inby the last open crosscut, is required to be measured using current torque wrench technology. The disadvantages of this system are the disturbance and weakening of the anchorage and limitations of accuracy to approximately ± 30%. The method by which resin-grouted bolting systems carry roof loads is much less understood, mainly because testing procedures used to evaluate point-anchor systems are not effective on resin-grouted bolts.Due to these problems, the U.S. Bureau of Mines designed a measurement technique that provided a highly accurate, low cost-per- bolt system that led to the development of ultrasonic pulse echo instrumentation. The original system was designed to measure the tension only on expansion anchor bolts. Recent developments and system modifications have permitted measurements on resin-assisted and full-column resin-grouted bolts. The use of these types of support systems has been increasing steadily in underground coal mines.The development of this instrumentation has provided laboratory and field results that help to explain the mechanics and relationships between the applied loads and the interaction between the grouted bolt system consisting of the bolt tendon, grout, and rock."

Jan 1, 1990

By S. Dallaire

"RÉSUMÉLes revêtements céramiques ont une moins grande visibilité que les revêtements métallurgiques. Ils ont cependant jour un role significatif dans noire développement technologique. Les procédés de revêtement ont permis de s'affranchir de barrières technologiques importantes dans le domaine de l'optique, de l'électronique, de l'usure, des hautes temperatures. L'introduction de nouvelles technologies ou la mise en service de nouveaux matériaux peut nécessiter l'adaptation de certain procédés actuels ou le recours a des procédés qui ont peu percé jusqu’ à maintenant.ABSTRACTApplications concerned with ceramic coatings are not as well known as those with metallic coatings. However, ceramic coatings have played a tremendous role in the development of technology. Ceramic coating processes made it possible to overcome technological barriers in the areas of optics, electronics, wear resistance and high temperature applications. Ceramic coatings can provide new properties to materials never considered for demanding applications. They can also open new frontiers and revitalize materials which are maturing or in decline."

Jan 1, 1990

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

By A. G. Pronk, D. M. Burton

"A regional till sampling program in the Upsalquitch Forks-Tetagouche Lakes area, centred some 70km west of the city of Bathurst, has proven an effective method for gold exploration in the heavily glaciated interior of northern New Brunswick. Prospecting activities within this area over the past three years, have led to the discovery of several gold occurences associated with quartz-carbonate alteration in a variety of intrusive rock types emplaced along major fault zonesQuaternary mapping shows that the glacial history is complex. However, the displacement of material is uniform in distance and direction, and the till is generally thin (0.5 m to 2.0 m) and locally derived, making the interpretation of till geochemical patterns relatively simple for the explorationist. Previous studies have shown the the fin e-grained gold is best detected in the -250 mesh (-0.063 mm) till fraction (clay plus silt) and that the C-horizon is the preferred medium for analyses.Samples were collected on a 2 km grid and analyzed f or Cu, Pb, Zn, Au, Ag, As, Sb, Mn, Fe, Ni, Co, and Cd. Results indicate that concentrations of 10 to 20 ppb Au can effectively delineate areas of anomalous gold in bedrock associated with fault structures, and that a good potential for discoveries exists to the west of the known occurrences, where up to 678 ppb A u has been detected in tills. IntroductionThis paper reports on the result s of surficial geological investigations conducted over the past two field seasons in north-central New Brunswick. The stud y area is located in the Upsalquitch Forks-Tetagouche Lakes map area s (N.T.S. 21 0 19 and 21 0 (10) 70 km west of the city of Bathurst (Fig. I). The area is situated on the margin of the New Brunswick Highlands and has a maximum elevation of 640 m (for a detailed description of the physiography, see Rampton et al. 1984).Historically, exploration in northern New Brunswick has concentrated on base metals within the Cambro-Ordovician Tetagouche Group, resulting in the discovery of man y significant massive sulphide deposits (Brunswick No.6 and No. 12, Heath Steele, Caribou, Armstrong Brook, Orvan Brook, McMaster, Murray Brook, and Restigouche). Auriferous base metal occurrences along the Rocky Brook-Millstream Fault have also been previously investigated."

Jan 1, 1988