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By J. J. Benitez

MIBC (methyl-isobuthyl carbinol) was previously shown to enhance significantly sylvite flotation when used at the stage of preparation of amine dispersions. In this paper Atomic Force Microscopy (AFM) is used to study the effect of MIBC on deposition of octadecylamine (ODA) on the surface of mica. The AFM images indicate that amino terminated, and therefore hydrophilic, deposits of ODA are observed on the mica surface in the ODA dispersions free of MIBC. In the presence of MIBC a methyl terminated (hydrophobic) monolayer is obtained on the mica surface. The transition between the monolayer and bilayer phases is due to the presence of MIBC. Experiments carried out in distilled water reproduced the results obtained from the brine. Working in pure water instead of brine simplifies the preparation conditions and the analysis by AFM.

Jan 1, 2006

By B. R. Boardman

Project Environmental Approval is a multi-faceted issue. From a mining perspective, it is a costly item because of avoidable time delay. The government perspective is that the approvals are a necessary part of meeting departmental requirements to ensure that the wellbeing of other uses of the environment is maintained. This paper outlines some of the problems inherent in the environmental approvals process and makes recommendations to both the proponent and government about improving the efficiency of the process.

Jan 1, 1978

By Frédéric Bélanger, George P. Demopoulos, Pascal Coursol, Thomas Feldmann

"The use of scandium in industrial applications is expected to rise in the coming years, in large part due to the expected adoption of new, clean energy technologies such as solid oxide fuel cells or Sccontaining high strength aluminium alloys. Given that the supply of Sc is currently dominated by only a few countries (Russia and China) other sources for scandium extraction need to be investigated. This paper looks at different options for the recovery of scandium from waste solutions generated during the production of TiO2 pigments via the chloride process route. In particular, a direct solvent extraction (SX) approach and possible options for concentrating scandium before the SX step were investigated. It was found that the presence of Ti during solvent extraction causes severe formation of stable emulsions, which can complicate the successful application. This was particularly a problem after multiple contacts of the organic phase with fresh aqueous phase. On the other hand it was noticed that the presence of certain elements in the solution, e.g., iron, could possibly be utilized to concentrate scandium in a solid precipitate.INTRODUCTIONMany newly developed high-tech products depend on the use of chemical elements that are only produced in very small quantities. This can result in high and fluctuating prices, as can be seen from Figure 1, which may cause substitution with inferior alternatives, if possible at all (Reck & Rotter, 2012; US Dept. of Defense, 2013; Whittaker, 2011). One example is scandium (Sc) a member of the extended rare earth element family. There are only a few scandium ore deposits, but most Sc is produced from the processing of by-products of other metallurgical processes (Melcher & Wilken, 2013). Increasing demand for scandium metal and oxide (Sc2O3, scandia) is coming from its increased use in applications such as ceramic lasers (Li, Ikegami, & Mori, 2005; Rainer et al., 1982), high strength aluminium alloys (Lathabai & Lloyd, 2002) as well as solid oxide fuel cells (SOFC) (Thijssen, 2011). Especially, the spread of climate friendly SOFC’s, which are a commercial product today (Bloom Energy, 2014), is expected to be a main driver for future Sc2O3 demand. However, the rate of market penetration of this green technology depends on the availability of high purity Sc2O3 (>99.999%), since it specifically contributes to longer life-time and better safety of the SOFC’s (Bloom Energy, 2014; Irvine, Politova, & Kruth, 2005)."

Jan 1, 2016

By Donald F. MacDonald

THE cement plant nearest to Nova Scotia is not far from Montreal. Cement is a heavy product which, because of its relatively low value, cannot stand a high freight charge without unduly enhancing its cost. This is one reason why cement costs are high in Nova Scotia. The regular retail price per bag (8772 lb.) in Antigonish is 85 cents, which would be $3.40 per Canadian barrel of 350 pounds, or $3.65 per American barrel of 376 pounds.It is said that the lowest wholesale price in Halifax is 65 cents per sack, which would be $2.60 per Canadian barrel or about $2.80 per American barrel. According to U.S. Bureau of Mines statistics, the average factory price for cement in 1937 was $1.48 per American barrel, which is practically the same as the value per barrel indicated in Dominion statistics for the Canadian output during that year. The difference between $3.40 and $1.48 is $1.92. It is evident that the average user of cement in the Mari-times pays a stiff premium because Maritime cement raw materials have not been developed. Rock-wool, the manufacture of which is rapidly increasing in Ontario and the United States, is much needed for building insulation in the cold climate of Nova Scotia.

Jan 1, 1939

By David R. Skuse, Jacek A. Kostuch, Steven M. Fortier

"Particulate ground calcium carbonate (GCC) is used as a filler and coating pigment in a wide range of applications including papers, paints, plastics and films. In this paper we will overview the requirements for GCC used in both filling and coating applications in the paper industry and highlight the processes used in the production of these materials.INTRODUCTIONCalcium carbonate is both abundant and very widely distributed occurring most commonly as limestone, marble and chalk (Harben 2002). Given, the high purity, whiteness and relative inertness of these materials it is not surprising that they are heavily utilised in a range of industrial applications. Worldwide ground calcium carbonate (GCC) capacity is estimated at 50.5 million tonnes per year (Roskill, 2002). This usage is divided between relatively coarse materials that are used in applications such as landscaping, cultured marble and carpet backing and finer grades that find application in plastics, rubbers, inks, paints and paper. Given the usage of calcium carbonate products across a very wide range of consumer products, the outlook for GCC is very promising with growth expected in many markets. Growth is anticipated across many applications in the emerging nations and more specifically in paper applications on a global basis.Over the last several decades the GCC processing industry has evolved to be well adapted to both the cost effective production and delivery of standard products and the production of high performance speciality products. Many of the standard unit operations found in the metaliferous raw material processing industry are also used, albeit in some cases in modified form, in the processing of GCC. Coarse products (diameter > 3 - 10 µm) are typically produced by dry processing routes. Whereas, the finer products are typically produced by a combination of wet and dry processing."

Jan 1, 2004

By Xing Jin, Dan Graffi, Glenn MacPherson, Dan Rioux

"The complexity of a modern flotation circuit makes it susceptible to disturbances such as changes in feed, ore mineralogy, equipment degradation, poor measurements and faulty instruments. Good measurements and a robust control system are critical to create and maintain a stable and optimum flotation process.This paper focuses on the development and implementation of process control applications in the flotation circuits at Xstrata Nickel’s Strathcona Mill ( referred to as the mill hereafter ) in Sudbury, Ontario. Following the path of ‘stabilize-improve-optimize’, basic controls to stabilize process variables such as flotation cell pulp level, air and reagent addition rates, cleaning-column feed and wash-water rates have been established. Factors such as best practice in pulp level and valve position measurement, feedforward control and the application of an appropriate control philosophy, have contributed to the significant reduction in process variability. For instance, standard deviation reduction of 79% for the Ni impurity in the column Cu concentrate grade was experienced and is shown. The variability reduction of the flotation circuits’ key process-variables paves the way to further improve and optimize flotation performance. A grams-per-metal unit reagent addition control scheme has been improved upon, particularly for different operating scenarios and better robustness. In addition, following significant stabilization of the primary controls and columns feedrates, Cu/Ni separation cleaning-column bias-control (cascaded to the wash-water rate) and hold-up control (cascaded to air flowrate) have been developed and tested. This strategy – from stabilization to optimization - is expected to achieve a more consistent control of final concentrate grades and improve recoveries.INTRODUCTIONFlotation is considered the most important and value-added process in the milling metallurgical plant and is still undergoing continuous evolution to treat greater tonnage and different ores (Wills, 2006). Starting over three decades ago, with the advent of on-line slurry content analysis devices, flotation automatic control has received persistent interest and a large number of applications have been reported (Thwaites, 1983, 1986 ; Mckee, 1991). Bergh and Yianatos (2011) reviewed different aspects of process control in flotation circuits and have evaluated the applicability of model predictive control to the process. Mckee (1991) analyzed the difficulty in developing lasting/robust process control applications for flotation circuits and stated that the path of stabilization-refinement-optimization would more likely lead to successful flotation circuit process control. Best practice on column process control was discussed by Bouchard, etc. where a multi-layered approach was proposed, provided that the measurement of column process variables ( i.e. bias, froth depth, hold-up, etc. ) are measured reliably (Bouchard & Thwaites, 2008). Wills (2006) stated that the best practice for flotation automatic control starts with fulfilling basic control objectives, such as stabilized flotation cell level, air flow, pH, reagent flow etc., before considering more advanced, or even optimal, control of metallurgical targets, which are more closely linked to economic performance."

Jan 1, 2013

By F. Andrieux

"Extruded aluminum profiles are increasingly used for lightweight vehicle construction. Since fracture strains of aluminum profiles are relatively low, damage modeling is crucial for reliable crash simulation. For aluminum profiles, not only the stress state but also the orientation influenced both the deformation and damage behavior. For the material characterization smooth tensile tests were performed in six orientations, both stress-strain curves and r-values were registered. Moreover notched tensile and shear-tension tests were performed in three directions. Finally punch specimens were tested to investigate biaxial loading. Digital image correlation (DIC) analyses were performed to determine local strain values such as critical values at failure. Numerical investigations were conducted with the strain based damage model GISSMO, which is well suited and widely applied for crash simulation. For a strain based failure model the choice of the deformation model is crucial. Deformation models with increasing complexity were investigated to find the best compromise over all experiments. It was found that there is still a great requirement on development of a material model which describes the orientation dependence of the hardening behavior over all stress states in order to be able to use a strain based failure model reliably.INTRODUCTION Weight reduction is an important step for less energy consumption and as a consequence aluminium is increasingly used in automotive parts. An important field of application is the well-established aluminium extrusion which allows the realisation of quite complex shapes of profiles required for an innovative lightweight design with integrated functions. Typical applications are chassis parts, bumpers, crash elements, air bags, etc. Especially the Al–Mg–Si medium strength alloys of the 6000 series can be easily extruded to form complex profiles and prevail for extrusion. Since fracture strains of aluminum profiles are relatively low, damage modeling is crucial for reliable crash simulation. For aluminum profiles not only the influence of the stress state but also the orientation with respect to the extrusion direction have an influence on both the deformation and damage behavior and need to be characterized. The effect of orientation on deformation behavior has been intensively investigated in the last decades and material models haves been proposed (e.g. Barlat & Lian, 1989; Barlat, Lege, & Brem, 1991; Barlat et al., 2003) to describe accurately anisotropic behavior. However it can be noticed that the parameters of anisotropic material models often rely on the yield stress in different directions, which means that the effect of strain hardening is not automatically accounted for. The accuracy of the models at large deformation is not guaranteed and has to be verified. In contrast to deformation models both the characterisation and the modeling of anisotropic damage behavior are not systematically studied. Isotropic failure models based on a critical strain as function of stress triaxiality (ratio of the hydrostatic stress to von Mises equivalent stress) are widely used for crash application (e.g., Bai & Wierzbicki, 2010; Sun, Andrieux & Feucht, 2009; Sun et al., 2013). The mechanisms of failure are manifold and not fully understood; to develop an anisotropic failure model it is mandatory to also have experimental data in different orientations for loading scenarios other than uniaxial tension, e. g. shear, biaxial tension, which implies an extensive experiment plan. This makes the development of failure models more challenging than deformation models for which it is possible to develop a reasonable anisotropic model using the framework of yield function and calibrate the material parameters based on results of tensile tests in different directions. Moreover the development of deformation and failure models are intricate as the variables governing the damage evolution are predicted by the def"

Jan 1, 2018

By J. R. Rau

While refuge chambers are common place in most underground mining projects, there are different philosophies as to what life support systems are to be considered and how these systems are to be applied. Case studies in the underground mining industry have examples of emergencies where the external compressed air and power supply to the refuge chamber were compromised due to proximity of services to the fire location. In 2005, The Department of Industry and Resources, Western Australia, drafted guidelines that listed specific requirements for refuge chambers which included a secondary life support system that would operate independently of external sources. The objective of this document is to examine what critical life support systems are essential for safe entrapment in the event of an emergency and to examine considerations for their application.

Aug 1, 2013

By G. Clarkson, M. Hitch, R. Clarkson

"A novel reagent-free method of extracting gold from gravity middling concentrates in the Yukon placer fields is presented in this paper. This method exploits the malleability of gold by submitting concentrates to grinding in a rod mill. Brittle waste minerals are effectively reduced, whereas malleable gold particles are flattened and are then extracted by classification through sieves. Recoveries in the field using a laboratory-sized rod mill regularly exceeded 90%, whereas correlation laboratory tests indicated recovery to be most sensitive to the mill charge size. This method has broad potential, including application to the gravity circuits of large hard-rock processing circuits.RÉSUMÉ Cet article présente une nouvelle méthode sans agents réactifs d’extraction de l’or dans les concentrés gravimétriques mixtes que l’on trouve dans les districts placériens du Yukon. Cette méthode exploite la malléabilité de l’or en broyant des concentrés dans un broyeur à barres. Les déchets miniers cassants sont bien réduits, alors que les particules d’or malléables sont écrasées puis extraites par classification au travers de cribles. Si les récupérations sur le site à l’aide d’un broyeur à barres de laboratoire excèdent 90 %, les essais de concordance en laboratoire indiquent que la récupération est très sensible à la taille de la charge du broyeur. Cette méthode présente un grand potentiel, notamment une application possible aux circuits gravimétriques des grands circuits de traitement des roches dures.INTRODUCTIONExploiting the high density of gold to separate it from waste materials is the oldest known mineral processing technique. This basic technique is still widely used in gravity concentration circuits today; however, gravity processing invariably results in high-value middlings, especially in the Yukon placer gold fields. In addition to having a uniquely high density, gold is also the most malleable metal. This unique malleability can be exploited to extract gold from otherwise inaccessible gravity middlings.The Yukon placer gold industry has been continuously ongoing since the 1860s, and today produces approximately 60,000 oz t (1.87 million grams) of crude gold annually, most of which is from the Klondike region near Dawson City (Van Loon & Bond, 2014). It is important to note that Yukon placer miners do not use any chemical extraction methods; rather, gravity upgrading methods are the sole processing techniques used. Placer deposits are typically coarse, well liberated, and naturally gravity concentrated and recoverable, thus making more expensive chemical extraction unnecessary (Mitchell, Evans, & Styles, 1997). Furthermore, a strict permitting regime, environmental concerns, lack of expertise, and fear of repercussions from regulators prevent miners from attempting more advanced processing methods, such as flotation or cyanidation. Even simple chemical extractions like mercury amalgamation have not been implemented for decades, with one observer noting that, as many as 30 years ago, “the art of mercury for amalgamating appear[ed] to be dying [in the Yukon]” (Osler, 1983)."

Jan 1, 2017

By Stephen Hardcastle

Personnel Heat Exposure Issues In Canada?s Deep Mechanized Mines ?Project developed in 2004 ?Base/precious metal industry identified heat stress/management as a major challenge affecting productivity and operating costs ?Project started in 2005 ?Current research nearing completion ?Guidelines, further data analysis and ?Communicating the Science? will continue into 2011 Managing Heat Exposure Control?. The cost implications ?Controlling the environment ?Ventilation already a major expenses/energy user ?Large Canadian mines are currently delivering massive volumes of air 15-20 tons of air/ton ore ?Large investments in ventilation upgrades, mechanical cooling

May 1, 2010

By B. Holaday, H. McLaughlin

Orano Canada Inc. (Orano) operates the McClean Lake mill, located in the Athabasca Basin region of northern Saskatchewan. It processes high concentration uranium ore, delivered in slurry form from the Cameco Corporation operated Cigar Lake mine. After the ore slurry is leached at the McClean Lake mill, the leach residue solids are washed in a process known as counter-current decantation (CCD). This process uses six thickeners to facilitate counter-current washing of solids with diluted acid, flocculation and settling, as well as pumping the washed leach residue to the tailings neutralization circuit (TN), and the uranium laden aqueous to the solvent extraction circuit (SX). Challenges in settling the slurry in CCD started in early 2017. This is largely due to the variation in fines content of the slurry (D80≤75μm), and clay content. There are several changes that have allowed the mill to adapt to the evolving challenges of settling leached Cigar Lake leach residue. Flocculant selection and mixing, temperature effects, bed level management philosophy, and centre-well feed density are key parameters that have been explored as part of adapting to changes in Cigar Lake ore quality.

Jan 1, 2020

By J. Stiksma, K. Buban, J. Oftsie, R. Kalanchey, S. Sadykov, E. McConaghy

The Kazakhmys zinc refinery in Balkhash, Kazakhstan, which employs the Dynatec Zinc Pressure Leach Process, officially launched autoclave operations on December 27, 2003. The Kazakhmys plant is the world's first greenfields zinc refinery based on Dynatec's two-stage pressure leach technology. Production of zinc was realized on February 9, 2004, when the first cathode was stripped. Currently the plant start-up is ongoing, with progression to two-stage zinc pressure leach operation and ramp-up to full design capacity continuing through 2004.

Jan 1, 2004

By Shek N. Lau, Nicola Samman

"Enclosed gear cases on board heavy mining equipment have traditionally been lubricated with regular heavy duty gear oils. However, equipment manufacturers, have recommended the use of an ISO-1000 gear oil for this application to ensure adequate lubricant film strength, especially at the higher end of the working temperature range. The majority of these ISO-1000 gear oils are based either on residual/asphaltic oil or synthetics, primarily higher viscosity polyalphaolefins. Although the performance of these lubricants has been satisfactory, they suffered other shortcomings that equipment users have lived with over the years.The major requirement at the user’s mine was to provide lubrication for the shovel Hoist gear case. Within such a gear case design, the gears and the roller bearings, that have different lubrication requirements, are lubricated with the same lubricant. Several lubricants were used, light gear oils as well as the recommended ISO-1000 heavy gear oils. On the one hand, the lighter oils performed adequately for the lubrication of the bearings that formed part of the enclosed gear system. These lighter oils did not perform as well for the lubrication of the gears due to their lower viscosities, resulting in shorter gear servicelives.On the other hand, the ISO-1000 gear oils performed well for the lubrication of the gears, but were too viscous to creep into the bearing elements to lubricate them adequately, especially during the cold northern Canadian winters. This resulted in catastrophic bearing failures and secondary damages to the gears.The challenge, then, was to formulate a lubricant which met the 1000 cSt at 40°C viscosity requirement as stipulated by the equipment manufacturer, while satisfactorily lubricating the bearings at the full working temperature range. This was achieved by the development of a semi-fluid grease lubricant, which has proven in field trials to give adequate performance in this application for the lubrication of both the bearings and gears down to -40°C.This product met the equipment manufacturer’s performance criteria and resolved, to a large extent, leakage of the lubricant through seals experienced with the use of conventional and synthetic gear oils.Although the main performance criteria of the fluid was its capability to lubricate the “Hoist” gear case, it was also used during the field trial in other gear cases on board the shovel to test its full capabilities.This unusual alternative lubricant was field tested and evaluated for more than two years. Based on this assessment, the product was reformulated to improve its fluidity, slumpability and the settling of debris/wear metals to the bottom of the gear cases. This reformulated softer grade, a semi-fluid grease, has been performing satisfactorily for more than eight months and is still undergoing longer term assessment."

Jan 1, 1996

By W. B. Paton

Introduction For several reasons the accident history of Flin Flon has been quite unlike that of any other mine in northern Canada, and very much unlike that of the average American metal mine. Towards the end of 1928, the mining project that is now Flin Flon, and that is now in the very: forefront of Canada's big producers was launched; but, metaphorically, it was launched in a tempest of mining troubles. Each branch of the mammoth enterprise was beset with extraordinary difficulties, and the Safety Department had its relative share. Difficulties in Accident Prevention The unusually rugged contour of the plant site made roads, and even moderately safe pathways, out of the immediate question. The project established an industrial outlet for depression-stricken areas which hitherto had been essentially agricultural; but through that outlet poured labour whose working atmosphere had been the bald prairie, labour that knew nothing of safety consciousness, labour that had to be moulded to industrialism, labour in the raw. A considerable length of the ore-body lay under the eastern section of Flin Flon lake. Open-pit methods were adopted to work the upper limits of the ore-body, and consequently the eastern section of the lake had to be dammed and pumped dry. The subsequent difficulties and hazards created by silt deposit cannot be fully visualized. And, finally, there was a geographical hindrance: the ore-body was partly in the Province of Manitoba and partly in the Province of Saskatchewan. The workmen's compensation problem became intricate. Insofar as accident prevention is concerned, Flin Flon's young industrial life may be conveniently divided into three distinct periods, namely: (a) Construction (Nov. 1928-June 1930) (b) Tuning up, and production till the strike (June 1930-June 1934) (c) Production from the strike till the present time At the peak of construction, due to the usual labour fluctuations of big jobs, there was a weekly turnover of about a hundred men. A very large percentage were Central Europeans, most of whom could neither read nor write English. Consequently, an organized safety programme was out of the question.

Jan 1, 1935

By Horace Freeman

Introduction In the aggregate, directly and ?indirectly, the pulp and paper industry ? consumes very large quantities of a variety of minerals, or compounds prepared from minerals. This is especially true in the manufacture of news-print, but fine papers, also, account for some of this consumption, in the processes of loading, coating, and otherwise improving the finish. The more important of the minerals used in the industry in Canada are briefly dealt with in the following pages. The list is by no means exhaustive, however. Thus, barite, lithopone, zinc oxide, zinc sulphide, and titanium oxide are used in small quantities in Canada in filling and coating paper. Up to the present time, however, the quantities of these materials used in the paper industry have not sufficed to encourage their manufacture in Canada. In the case of barite (barium sulphate)-or of witherite (barium carbonate)-it may be said that, should deposits of commercial size be discovered in Canada, the ore would have considerable export value, for use in the paper and other industries. China-Clay (Kaolin) Considerable quantities of china-clay are used for brightening and improving the finish of paper, and there is a growing tendency to use larger amounts of this material in newsprint manufacture. No china-clay suitable for paper manufacture is at present produced in Canada, but samples have been forthcoming recently from a deposit near St. Remi d'Amherst, Labelle county, Que., about thirty miles north of the Ottawa river and approximately midway between Montreal and Ottawa, and plans are under way to conduct large-scale tests with this material. Present sources of supply are the United States, England, and Russia.

Jan 1, 1934

By N. Schreithofer

The deposition of octadecylamine (ODA) at the KCI crystal/NaCI-KCI brine interface was investigated using atomic force microscopy (AFM). The AFM images of freshly cleaved KCI specimens immersed in KCI-NaCI saturated brine at room temperature reveal disappearance with time of the atomic steps and formation of cubic NaC1 crystals. These crystals were found to form when the specimen was withdrawn from the saturated solution. Depending on the way of contacting the specimens with the octadecylamine dispersion, the AFM images show huge differences in the deposition patterns of ODA on KCI crystals. Adequate dispersion was found to help the formation of quite even ODA coverage. The coverage was several monolayers thicker when air/brine/solid contact took place, suggesting that in the potash flotation the collector is likely to be carried to the solid surfaces by air bubbles. The presence of methyl-isobutyl carbinol (M IBC) enhanced the dispersion of ODA in brine, thus helping the spreading of the surfactant on the KCI crystal surface.

Jan 1, 2006

By G. M. Brownell

Introduction The Flin Flon mine is located on the boundary line between the provinces of Manitoba and Saskatchewan at a point about four hundred miles northwest of Winnipeg. A branch of the Canadian National railway provides the town of Flin Flon with direct transportation facilities. The property was staked in 1914 and, after a considerable amount of exploration; the Hudson Bay Mining & Smelting Company was organized and brought the property into production in November, 1930 (1). Mining is carried on by open pit and underground methods at the rate of about 4,400 tons per day. Production for the year 1934 was: 99,334 ounces of gold; 1,335,319 ounces of silver; 37,486,054~pounds of copper; and 49,427,280 pounds of zinc; in addition to small amounts of cadmium and selenium. The Flin Flon deposit is one of the largest low-grade ore deposits in Canada with complete hydro-electric and metallurgical plants for the production of blister copper and electrolytic zinc. Previous Work The development of the Flin Flon mine into one of the major mining operations in Canada has created a need for a more detailed geological study of the area. Practically all of the information published to date concerns the general surface features. It is the purpose of this paper to deal more specifically with the ore-body and its relationship to the enclosing rock as revealed by studies made possible through recent underground development. The earliest published report on the area is by E. L. Bruce (2), who made a reconnaissance geological investigation of the region for the Geo-logical Survey of Canada in 1914 and established the main. petrological units. Several years later the area immediately around Flm Flon was mapped in greater detail by F. J. Alcock (3). In the summer of 1934, the area of Missi sediments to the north and east of the mine was studied by J. W. Ambrose. His report has not yet appeared in print but his findings are of importance.

Jan 1, 1935

By F. K. McKean

Introduction The present paper may be considered as a sequel to a paper, A Process for Cleaning Molybdenite .Concentrate, which was presented by the author at the annual meeting of the Institute last year. In that paper, a description was given of the laboratory work leading up to the adoption of a new process for treating complex molybdenite ores of the Molybdenite Corporation of Canada. A bare outline of mill performance with the new flow-sheet was included. With this writing, the purpose is to describe the highly interesting work of translating laboratory experience into mill practice, to show what changes were required in design to put the scheme on an operational basis, and to point out the gratifying improvements in mill products which resulted from the new procedure. The process has been placed in operation at the La Corne mine of the Molybdenite Corporation of Canada. This mine was operated during the war by Wartime Metals Corporation, and, earlier, by the Molybdenite Reduction Company, which installed a small plant. The property is situated on the highway from Amos to Val d'Or, Quebec. The claims held by the Company are at the boundary between La Corne and Vassan townships.

Jan 1, 1947

By B. Dubé, R. Friedman, J. Oliver, R. Aubertin, M. Burson, G. Panneton, M. Hamilton, J. Ayer

"Abstract — The Detour Lake gold deposit is located within the northwestern limit of the Archean Abitibi Subprovince of the Superior Province. Mineralized zones are hosted by a sequence of pillowed and massive flows, hyaloclastite units, and altered ultramafic rocks, and are commonly oriented parallel to a series of high-strain zones that are co-planar to the regional-scale Sunday Lake Deformation Zone. Early in its kinematic history, the Sunday Lake Deformation Zone placed older (2.72 Ga) volcanic rocks of the Detour Lake Formation over younger (2.70 Ga) sedimentary rocks of the Caopatina assemblage. Gold mineralization is also parallel to the position of a laterally persistent siliceous rock unit, the 2.725 Ga ‘Chert Marker Horizon.’ The Chert Marker Horizon coincides with the boundary between the mafic-dominated upper Detour Lake Formation and the ultramafic-dominated lower Detour Lake Formation. Stratigraphic and geochronological data suggest that the Chert Marker Horizon is a deformed felsic volcaniclastic unit. At a cut-off of 0.6 g/t Au, the Detour Lake deposit contains 17.26 million ounces of Au within 445.9 million tonnes of rock grading 1.20 g/t Au. Gold occurs in shear-hosted and extensional vein arrays within rocks of the upper and lower Detour Lake Formation and within the Chert Marker Horizon. The Detour Lake deposit has many of the characteristics of a greenstone-hosted, quartz-carbonate vein deposit; its very large size may be attributed to large-scale rheological controls resulting in the formation of dilatant sites in permissive rock units. © 2012 Canadian Institute of Mining, Metallurgy and Petroleum. All rights reserved."

Jan 1, 2012

By Neil Campbell

Abstract Following discovery on the Giant property of very promising gold deposits, some of which terminate against the steeply-dipping West Bay fault, a geological study was initiated co locate possible faulted extensions of the ore. Geological mapping revealed that the ore and the shear zones to which the ore is confined are older than the fault and therefore subject co displacement by it. It also disclosed several diabase dykes which seem co provide the best basis for determining the fault movement. After applying various techniques co determine their strikes and dips, the dykes were used as structural markers and it was estimated that, subject co certain possible errors, the movement on the fault was 16,140 feet (3.06 miles) south and 1,570 feet (0.297 miles) down on the west side relative co the ease. Evidence supporting this conclusion was obtained when subsequent deep diamond-drill holes intended to test the hypothesis cut an ore-bearing major shear zone which, so far as can be determined, is nearly identical with its present correlative on the Giant property. Introduction The fault under consideration follows a northerly trend past the west side of the original settlement of Yellowknife, which is situated 600 miles north of Edmonton and 400 miles from the Northern Alberta Railway terminus at Waterways, Alberta. The mining properties chiefly concerned include the southern part of the Giant claims, on the east side of the fault, and the Con-Rycon-Demelt claims, on the west side, 3Y2 miles to the south. Geological data were also obtained from the eastern part of the A. Y.E. property, which lies south of the Giant claims, and from the Negus, Meg, Yellorex, and Kam properties, which are south and southeast of the Con-Rycon-Demelt claims. Recognition of the major faults in the Yellowknife Bay area, including the West Bay fault which appears to be the greatest, resulted from the work of Dr. A. W. Jolliffe (McGill University, formerly of the Geological Survey of Canada) in 1935 and subsequent years. It has been stated with little exaggeration that these faults rank with the largest known steeply-dipping dislocations of the earth's crust. In the winter of 1939, a mineralized shear zone named the Creek Vein was found on the Giant property. It was noticed that the space relationship between the new shear zone and a body of quartz-feldspar porphyry is roughly the same as that between the Con C-4 shear zone and a body of acidic flows lying north of the Con property. Coupling this relation with the assumption that the movement along the fault is dominantly horizontal, it was postulated that the Giant shear zone represented the faulted extension of the Con C-4 shear.

Jan 1, 1947