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By H. Craig Boyle, Craig H. B. Leitch

"The Trout Lake stockwork molybdenum deposit is located in the Selkirk Mountains of British Columbia, 50 km southeast of Revelstoke. The property is being explored by a joint venture between Newmont Exploration of Canada and Esso Minerals Canada.The deposit is associated with a small granodiorite stock of Upper Cretaceous age (76 Ma) which has variably altered the surrounding schists, argillites and marbles of the lower Paleozoic Lardeau Group to hornjelsic biotite schists and skarn. The intrusive is composed of a small stock and an intersecting network of northeast- and northwest-trending dykes at surface that coalesce downward into a larger stock. There are two main phases of intrusion, with an earlier quartz porphyritic granodiorite cut by an intra-mineral ""quartz diorite"" porphyry. A strong sub-vertical north-trending fault controls the distribution of the mineralized stock work and displays post-mineral movement.Molybdenite, accompanied by pyrite and pyrrhotite, is mainly present along the margins of veins in a well-developed quartz stock work, but occasionally is strongly disseminated in microfractured intrusives. The stock work is strongest in and around the contacts of the intrusive and its apophyses, and occurs over a vertical range of more than 1,000 m. As defined by the 0.10% MoS] contour, the main mineralized zone is up to 300 m long by 200m wide. Preliminary drill-indicated reserves, currently being revised, are approximately 50 million tonnes of 0.23% MoS2, within which are several zones of higher-grade material. Hydrothermal alteration, as defined by quantitative X-ray diffraction studies on composite core sections, is composed of a central quartz/K-feldspar/albite/minor biotite zone coincident with molybdenum mineralization, which is overlapped by a slightly later, antipathetic quartz/ sericite/pyrite zone. Ankeritic carbonate is also a common alteration mineral, but only traces of fluorite, and no topaz or sulfosalts, have been observed. Analysis for trace elements such as Sn, W, Bi, Sb, As, Hg, U, Ag, Au, Mn, Cu, Pb, Zn and F has been limited except for Sn and W, which appear to be zoned inside and outside the Mo zone respectively; the other elements do not show detectable patterns thus far."

Jan 1, 1983

By A. Galip Ulsoy, K. V. S. Sastry

"This review paper is intended to provide, the mineral process engineer with an introduction to the concepts, terminology. and practice of mineral process control. It also provides an extensive sampling of the vast body of literature relevant to this topic. The topics discussed include the principles of automatic control, instrumentation, mineral processing unit operations, process modeling and simulation, and process and plant control. IntroductionEconomically accessible higher-grade ores are being rapidly depleted, and at the same time the demand for mineral raw materials continues to increase. Mineral recovery from the remaining low-grade or finely dispersed ores requires grinding for liberation. High energy consumption during grinding and poor efficiency associated with the beneficiation of fine minerals are two important problems facing the mineral industry . These problems, coupled with advances over the last 10 to 15 years in the areas of process modeling, instrumentation, computer technology and control theory, have made automatic control of mineral processing systems an important research area(23,52,66,67,120,129,152)."

Jan 1, 1981

By R. G. Rosehart, S. Y. Lee

"The current investigation concerns the removal of arsenic from waste waters using ion-exchange resin and activated carbon as sorption media. Use of certain weak and strong base anion exchange resins permits the removal of arsenic. Arsenic may be loaded on the weak base resin in the pH range of 2 to 3 and on the strong base resin above pH 5. The elution of arsenic is successfully achieved using 0.5 M NaCl or a mixture of NaCl and NaOH. The activated carbon investigated was less effective on loading arsenic, but the arsenic loaded was easily eluted by simple pH adjustments."

Jan 1, 1972

By R. A. L. Drew, G. Mendoza-Suarez, J. Filipi, R. Vintila, J. A. Kozinski

Economics and environmental considerations along with the increasing demand of hydrogen encourage development of novel technologies such as plasma processing of hydrocarbons and thermal cracking of natural gas. Plasma discharges, either in thermal or non-thermal regimes are expected to allow low temperature and fuel flexible on-site hydrogen generation. The main drawback of thermal plasma reformers is the high-energy consumption resulting from high-temperature operation. On the other hand, non-thermal plasma, generated by dielectric barrier discharge (DBD), is able to simulate the chemical reactions employing much lower energies than those required by thermal treatment processes. The non-thermal plasma process allows for instance, a direct conversion of methane into hydrogen and carbon black with no CO2 release. The focus of this research was on the GHG-free method of H2 generation in compact non-thermal plasma reactors using low, medium and high permittivity dielectric ceramics. A stable, non-thermal plasma was generated by placing a dielectric ceramic between two electrodes with a 25 thou gap and applying an alternating current of 1-5kHz and voltages of 4-8kV. In order to ensure energetic efficient plasmas, experiments were conducted to analyze the behaviour of different permittivity ceramics. It was found that the dielectric properties of a ceramic, when used in a DBD reactor, have a strong influence on the discharge characteristics, which in turn influence the power consumption. Higher dielectric constant resulted in higher conversion rates of methane (higher yield of hydrogen and carbon). At the same time, the mechanical properties of the dielectric material, which are closely associated with its processability, influenced its resistance to electron bombardment, as well as thermal and mechanical damage. Therefore a reliable ceramic should have good dielectric properties, in addition to good thermo-mechanical stability.

Jan 1, 2004

By E. L. Chanturiya

The research and characterisation for compositional, physicochemical, structural, electrical and flotation properties of various pyrite samples for a copper-zinc sulfide ore was carried out. Various methods were used during the research, such as optical microscopy, X-ray diffraction, electron probe micro-analysis (EPMA), phase emission analysis, routine chemical analysis, auger electron spectroscopy (AES), scanning electron microscopy (SEM), back-scattered electron images (BSE), potentiometry, and instrumental neutron-activation analysis, flotation. Analysis of obtained results established the interrelation between impurity structures and concentration of electric charge carriers in minerals, Butyl xanthate sorption and flotation yield of pyrite. The research concluded that pyrite samples differ by morphology, micro defects of structure, concentration of donor and acceptor impurities (Co, As, Sb, etc.) and conductivity parameters (thermo-electrical force, specific resistance and concentration of charge carriers The peculiarity of pentagon-dodecahedral pyrite is the high concentration of electric charge carriers (electrons) and the more negative surface potential (by 25–75 mV) in comparison to cubic pyrite. The surface of cubic varieties is more active, therefore it is oxidized in alkaline lime medium much faster, than the surface of pentagon-dodecahedral varieties. This phenomenon is caused by high reaction ability, irregular jointing and defects of cubic pyrite. This promotes the increase of calcium ion sorption on its surface and the decrease of Butyl xanthate sorption. According to this, an increase in alkalinity (lime medium) from a pH of 10.0–11.5 leads to an increase of gold content reporting to the tail of bulk flotation. Gold content is increased from 0.58 g/t (?? 9.5) to 1.9 g/t (?? 11.6), which represents an increase in gold recovery of 24.68 to 79%, respectively.

Jan 1, 2016

By J. George Gregr

"This paper gives a brief review of grinding mills installation procedures with special emphasis on future maintenance. The importance of cooperation between the customer, construction contractor and manufacturer's representative is discussed, as well as the imparlance of complying with standards, specifications and the keeping comprehensive installation records.Fundamentals of mill maintenance are explained with the aim being to maximize the equipment availability and to minimize unscheduled downtime. The paper also includes development of wear items design, based on operating conditions, drive components and bearings, and how to keep large gears healthy thus eliminating surprise failures.Experience with installation of a large gear on a 34-foot diameter mill in Lornex and successful application of a computer program for the gear alignment on the mill are given.IntroductionSuccessful operation of a concentrator begins with the engineering of the project and continues through selecting the right equipment, its installation , start-up period, and ends with final tuning of the process. machinery and the human factor into an efficient and viable industrial complex.The following is a brief review of grinding mill installation procedures with special emphasis on future maintenance. Fundamentals of mill maintenance are discussed with the aim being to maximize the equipment availability and to minimize unscheduled downtime, with some specific points on key grinding mill components such as bearings and drives.Finally, the experience is recounted with the installation of a large ring gear on a 34-foot diameter mill at Lornex, and the successful application of a computer program for the gear alignment on the mill."

Jan 1, 1985

By John W. Bell

A FEW years ago the writer had the privilege of examining a piece of apparatus in the Forest Products Laboratory of McGill University which engaged his attention. The Forest Products Laboratory has an excellent installation of wood-grinding machinery, and the officials in charge were naturally interested in acquiring means for estimating the fineness of various wood grinds. The problem was referred to Dr. O. Maass ( l ). Dr. Maass designed a piece of equipment to measure the surface of a wood grind and derived an equation applicable in calculating its value, as follows : After inspecting this apparatus, the writer was disposed to believe that, with some modifications, Dr. Maass' ingenious idea might be utilized to measure the surface of mineral powders. Obviously, some difficulty would be found in maintaining an even suspension of mineral particles of high specific gravity compared to that of wood pulp. The writer will not bore the reader with a description of the various machines built and tried out. Some of these were satisfactory enough to obtain some valuable information, and to bring to light a difficulty which threatened to bring the investigation to an abrupt ending. For the mineral quartz, it was found that Kin the formula above stated was not a constant.

Jan 1, 1944

By Dale A. Walters

The thermal recovery of bitumen reservoirs by steam assisted gravity drainage (SAGD) is often designed to maximize the operating pressure. In general, the benefits of higher operating pressures are higher steam temperatures that maximize the reduction of oil viscosity, potential permeability enhancement associated with lower effective stress and shear dilation, and a larger pressure window to allow flexible control of the producer. This is especially important for shallow reservoirs where the pressure window for injection and production is smaller. Higher operating pressure can reduce thermal efficiency (due to heat losses), but the other benefits usually compensate. The limitation of the maximum operating pressure is then based on maintaining caprock integrity. Thus, shear and tensile failure mechanisms must be quantified and managed. This paper presents a geomechanical analysis of caprock integrity for SAGD operation. Both analytical and numerical approaches are used to investigate the modes of caprock failure. Main factors in the analysis are the knowledge of the initial stress state and proper representation of the complexity of the geomaterials. Typical initial stress states for northern Alberta are presented showing the potential for low initial minimum total stress and elevated initial shear stress levels. The stress-strain behavior for the sand and caprock materials is discussed focusing on the potential for shear dilation in the sand and shear strength behavior in the caprock. Elasto-plastic constitutive models used to represent the sand and caprock are presented and compared using numerical analysis. The increase in pressure and temperature alter the stress state and disturb the soil matrix. This disturbance results in shear dilation of the sand matrix creating regions of enhanced permeability and porosity. Also, the transfer of stress and strain to the caprock causes dynamic stress changes and, therefore, dynamic behavior of shear and tensile failure conditions. Calculations are presented showing the stress paths associated with SAGD operations, suggesting better design of lab testing programs and the implications for shear dilation in the sand and shear failure in the caprock.

Jun 1, 2012

By M. Cossette, V. H. Tran

"How can the durability of asphalt pavement be doubled without increasing highway budgets? Asphalt containing asbestos can provide the desired performance with additional costs being made up by longer life. The addition of a low percentage of asbestos to an asphalt mix permits a higher asphalt content without any consequent loss in stability. It is mainly the higher asphalt content that provides improved performance and durability, although the fibrous reinforcement plays a key role in preventing the propagation of micro-fissures. As well, several international studies show that, thanks to the latest production techniques, no environmental hazards need be incurred.RésuméComment doubler la durée des chaussées d'asphalte sans augmenter les budgets de voirie? L’asphalte contenant de l'amiante peut offrir les performances souhaitées et l'augmentation des couts initiaux peut être rapidement compensée par une durée prolongée. L’addition d'une faible teneur en amiante courte il l'enrobe de bitume permet des teneurs en bitume plus élevées sans subir une perte de stabilité en conséquence. C'est principalement la teneur accrue en bitume qui assure un améliorations propriétés physiques et une augmentation des performances mécaniques, ainsi qu'on prolongement de la durée. Cependant, le renforcement fibreux joue un rôle clef en prévenant la propagation éventuelles micro-fissures. Les nouvelles techniques évitent tous risques environnementaux"

Jan 1, 1991

By L. Rosato

In the past decade, as a result of increasing iron loads, Canadian Electrolytic Zinc (CEZinc) has become a pioneer in understanding the critical factors that affect the roasting of concentrates with high pyrite contents as well as those factors governing the effects of high iron loads on the leaching circuit. De-bottlenecking efforts in the roaster and acid plant section of CEZinc have given rise to a better appreciation of the impact of iron on roaster productivity. High standards for impure solution quality, zinc recoveries and residue disposal have all led to an increased comprehension of the limits of the leaching circuit and the optimization potentials with respect to iron and ferrites. In this paper, the impact of iron on the roasting and leaching circuits of CEZinc will be reviewed and special emphasis will be given to some of the more recent process optimization and improvement activities.

Jan 1, 2006

By Akihiko Nishiyama

Unmanned construction technology used for remote control operation of construction machines has some problems to solve compared with manned operation of construction machines, such as fatigue due to long-term operation or decreases in operational efficiency. To solve these problems, we recorded the viewpoints of operators in both manned and remote control operation and analyzed the differences. This paper reports on our discussion of improving the operability of remote control operation based on the analysis results.

Aug 1, 2013

By B. Rivard, D. Francis

A layered Archean magma chamber is exposed at the base of the Yasinski segment of the La Grande greenstone belt. This intrusive complex lies beneath a sequence of mafic volcanics and is underlain by granitoid basement which is crosscut by a swarm of gabbroic dykes. The gabbros of both this complex and the dyke swarm of gabbroic dykes. The gabbros of both this complex and the dyke swarm define a pronounced Fe-enrichment trend. The volcanic patterns of the La Grande and Eas tmain greens tone belts, however, define a series of iron depletion trends which originate in the iron enrichment trend of the gabbroic intrusives. These patterns suggest that the gabbros produced in the intrusive complex may serve as parental liquids for some of the lava suites of the James Bay greens tone belts.

Jan 1, 1984

By M. Moats, J. A. Gonzalez

A review of operating practices in zinc electrowinning plants is presented in this paper. Surveys were sent to several zinc electrowinning plants and data provided by some of these plants was compiled in a database. Information about anodes and cathodes, electrolyte composition, stripping methods, cells, electrical systems, and additives was compiled and analyzed. From the data analysis, correlations between operating variables are presented. Recent trends in operational practices are also highlighted.

Jan 1, 2008

By K. Hambrice, E. Fauveau

"When it comes to measuring the level of bulk solids, liquids, and everything in between, guided-wave radar technology now offers more level-detection capabilities than ever before. For an ever-widening range of previously hard-tomeasure products such as molten sulphur, liquid ammonia and petrochemicals, guided-wave radar transmitters provide accurate level measurements even under harsh chemical environments, wide variations in operating temperatures and pressures, and low dielectric constants.Great strides have been achieved in making these units easier to configure to a variety of process applications coupled with the simplicity of integrating these devices with most digital communication protocols. These improvements come as welcome relief to process engineers within an expanded range of level applications across several different industries that seek solutions to measuring the contents of tanks, silos, hoppers, bins, mixing basins, and vessels.Because radar transmitters have no moving parts, radar has already established a dominant niche in level measuring that quickly distances itself from mechanical means, which do not hold up as well in dirty service. Radar achieves its nonmechanical level detection capability by measuring the time of flight of the transmitted signal.Known more accurately as time domain reflectometry (TDR), the process involves sending microwave energy down into a vessel. When the pulse of radar energy reaches the product (indicated by a change in impedance), part of the pulse is reflected back toward the transmitter.A receiver measures the exact duration of time between the transmitted and reflected signal — the “time of flight.” The device analyzes this time and ultimately displays the level of the product as a distance in feet, metres, or other engineering units."

Jan 1, 2003

By E. W. Mountjoy

THE Exshaw formation is a thin but very persistent black shale unit generally well exposed along the easterly scarp faces of the fault blocks comprising tl1e front ranges of the Rocky mountains. It is over lain by the Mississippian Banff shales and silty shales and underlain by the massive Palliser Limestone formation of late Devonian age. The Exshaw continues eastward under the plains of Alberta and on into Saskatchewan, with little change until it reaches the surface of the Palaeozoic-Mesozoic unconformity. During the summer of 1953, the writer was working- with a field party under Dr. J. L. Usher in the front ranges of the Alberta Rocky mountains. This party, sent out by the Mobiloil Company, conducted a geological survey of Devonian rocks between the towns of Banff and Jasper. The writer helped to describe and map these Devonian rocks and obtained first-hand information concerning the Exshaw shale and its relationship to the underlying and overlying sediments. Additional information was obtained from reference material and from a number of geologists whom the writer has consulted. Grateful acknowledgment is offered to them, to the Mobiloil Company for releasing field information, and to F. W. Beales and W. P. Hancock who helped edit the original paper for publication. Information from areas north and smith of that studied and from bore holes on the prairies is referred to. Localities mentioned may be found in Figure 1.

Jan 1, 1956

By N. Tounsi

The use of analytical modeling of continuous chip formation in conjunction with orthogonal cutting experiments was presented in the open literature to identify the coefficients of material constitutive equation within the practical range of stress, strain, strain rate, and temperature encountered in metal cutting. Identification of reliable constitutive data was hampered by a lack of a reliable model for the prediction of the primary shear zone thickness that affects directly the effective strain rate field. An original analytical model to determine the primary shear zone thickness is proposed in this paper. It is based on the mechanics governing the material flow in the primary shear zone. Based on the distribution of the hydrostatic pressure and the forces measured from orthogonal cutting tests, the model that describes the thickness of the primary shear zone is derived. To validate the model, FE simulations of chip formation using DEFORM3D were carried out for different materials and cutting conditions. The results of the analytical model are in reasonable agreement with FEM results.

Jan 1, 2006

By D. B. Stewart

This paper reports on an investigation undertaken to determine the exhaust gas temperatures of operating underground mining equipment. The effectiveness of platinum catalytic purifiers is discussed. From exhaust temperatures, it is concluded that LHD engines are highly loaded, haulage truck engines are moderately loaded and utility vehicle engines are lightly loaded.

Jan 1, 1979

Open pit production planning is a procedure consisting of multiple stages. Although all the planning stages rely on the geostatistical block models, long- to short-term plans each require their appropriate resolutions and levels of details. The main motives behind using different resolutions are the tractability of the models and the practicality of the generated schedules. The current approach in the mining industry is to use nested pits generated by Lerchs-Grossman as the basis for long-term planning and to use manually generated polygons, within those pushbacks, as the units of production control in mid- and short-term planning. However, the nested pits generated by Lerchs-Grossman algorithm and the polygons drawn by mining engineer do not provide control over the value and tonnage of ore and waste inside the planning units and therefore cannot lead to optimum solutions. In this paper, we first present a pushback determination approach which maximizes the profit of the mine with control over the tonnage of ore and waste within each pushback. We then propose a clustering approach with size and shape control that determines aggregates within those pushbacks; and finally, we introduce a mathematical programming model which uses the generated pushbacks and aggregates as the planning basis and generates production schedules that maximize the net present value of the operation and are practical from the operation?s point of view.

Aug 1, 2013

By W. J. Jenner

"Introduction The Saskatchewan Power Corporation is a provincial crown corporation which operates under a mandate to supply all customers within Saskatchewan with electricity and natural gas. The Saskatchewan Power Corporation operates two coal mines within the province of Saskatchewan. The Souris Valley Mine is located a few miles south of the city of Estevan and produces approximately 300 000 Mg of lignite per year. The lignite is shipped about four kilometres by truck and burned at the 882 MW Boundary Dam Power Station, also owned by the Saskatchewan Power Corporation. The Poplar River Mine is located just south-west of the town of Coronach, Saskatchewan which is some 190 kilo metres west of Estevan. This mine produces approximately 1 675 000 Mg of lignite per year. The lignite is shipped seven miles by rail to the Saskatchewan Power Corporation's Poplar River Power Station. The Poplar River Mine is the sole sup plier of fuel to the Poplar River Power Station, which generates some 300 MW of electrical power. A second 300 MW unit is due to be commissioned at the Poplar River Power Station in mid-1983 and the Poplar River Mine will have doubled its capacity to approximately 3 350 000 Mg per year by that time: Souris Valley Mine Geology The Souris Valley Mine extracts lignite from the Estevan seam of the Ravenscrag Formation. This formation is of Tertiary age and was deposited during the Paleocene Epoch. The Ravenscrag Formation outcrops throughout southern Saskatachewan and all coal mined in the province occurs in this formation. Ravenscrag sediments are deltaic in origin and are composed of a series of fine sands, silts, clay and lignite deposits."

Jan 1, 1985

By B. Karnath, K. Guha, S. Tandon

At Jhagadia Copper Ltd (India), Copper is produced through secondary route using Top Blown Rotary Converter (Kaldo Furnace). The basic raw material being treated includes Matte-slag Reverts, Copper Cakes, dross & Cement, Oxide Ore, Low S bearing Concentrates & various metallics along with high grade copper scraps. The plant has capability to refine & produce Blister grade copper from Kaldo furnace as well as PS Converter . Blister is fire refined in Anode furnace & electro refined in Refinery to produce cathode copper. Our product , Copper Cathode , has already been established in the market as its quality is better than 'LME Gr'. The paper deals with the experiences encountered during commissioning & stabilization of the plant.

Jan 1, 2007