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By James Stenhouse

Abstract The aqueous oxidation of pyrite in caustic solutions under oxygen pressure was investigated by measuring that effect of reaction variable on oxygen consumption by the reactions. From the results of this investigation, a model for the process has been proposed. In this model, sulphur diffuses as a positive ion through an oxide layer which forms on the sulphide particles and is then oxidized to sulphate ion. Iron is oxidized by substitutional diffusion of oxygen atoms into the oxide layer. The effect of most reaction variables on the rate of oxygen consumption can be explained with this model. Introduction Recent investigations (1,2,3) have shown that certain sulphide ores can be readily leached by agitating the ore in the form of a pulp under pressure in the presence of oxygen. Since very little was known of the mechanism of this oxidation, a programme of investigation was inaugurated in 1949 in the laboratories of the Department of Mining and Metallurgy of the University of British Columbia. Financial support for the investigation was received from the National Research Council in the form of student grants and bursaries, from the Canadian Liquid Air Company, Limited, and from the Consolidated Mining and Smelting Company of Canada, Limited. The first objective was to devise a technique to study the primary oxidation reactions in aqueous solutions and to apply the technique to a detailed study of the oxidation of pyrite in caustic solutions.

Jan 1, 1952

By J. Mullins

Coal was first banked by the Dominion Coal Company, Limited, in 1898, near No. 2 Colliery, the same site as is presently used for that purpose. Though today there are banks at Glace Bay, Sydney, and Sydney Mines, these notes, except when otherwise desirable, will be confined to describing the practice as developed at the No. 2 Banking Station, Glace Bay, as being typical of methods obtaining at all sites. Storing The manner in which the coal was piled is illustrated diagrammatically in the accompanying sketch. A train of coal was brought on the main trestle, which extended the full length of the banking ground at a height of 22 to 39 feet above the natural surface, and dumped into bins which were integral with the trestle work. Chutes from these bins permitted the coal to be fed into 3-ton cars, which were horse drawn laterally on narrow gauge tracks laid about 10 ft. centres, to a maximum distance of 400ft. from the trestle. These cars were end-dump and as the pile extended laterally the narrow gauge tracks were lengthened by shorter or longer filling pieces, so that their ends were always kept at the brow of the bank. Much coal, however, had to be dumped directly on the tracks and hand trimmed to fill the valleys, and level off, between the tracks.

Jan 1, 1931

By Jean Descarreaux

"The Rexspar uranium deposits are located near Birch Island in central British Columbia. The property lies within the Omineca crystalline belt of the Cordilleran Orogen. Gneiss, schist, tuffaceous and porphyritic trachyte are the main rock types encountered on the property. These rocks are of pre-Late Triassic or probable Mississippian age.Lenticular bodies of mica and pyrite-rich rock are the host of three closely spaced uranium deposits and are found close to a fluorite deposit. The altered trachytic rock as well as the fluorite and uranium deposits are found in the upper part of the trachyte unit. The latest tonnage estimates are 1,441,820 tonnes averaging 23.46% CaF, for the fluorite deposit, 490,966 tonnes of 0.084% U10afor the 'W' deposit, 164,290 tonnes of 0.074% UP8 for the ""B"" deposit and 459,124 tonnes of 0. 071 o/o UP8 for the ""BD"" deposit.A hydrothermal replacement origin was first proposed for the fluorite and uranium deposits. The mineralizing and altering solutions would have been genetically related to a felsic batholith outcropping a few kilometres south of the property. Another hypothesis has been proposed more recently. A volcanic centre has been tentatively identified in the upper part of the trachyte unit, close to the mineral deposits. The fluorite and uranium deposits could possibly be volcanogenic, rather than related to the Cretaceous felsic batholith.IntroductionFluorite and uranium mineralization occur on the property of Consolidated Rexspar Minerals and Chemicals Ltd. in central British Columbia. The exploration and development works executed over the years are summarized in this paper. The deposits and their geological environment are described but the origin of the mineralization has not been definitely established."

Jan 1, 1986

By G. Simard, D. Boudeville, A. Leclerc, A. Boivin

"The objective of this work is to study the various parameters that affect the overflow clarity of gravity settlers used in the precipitation circuit of alumina hydrate from the Bayer process. A mathematical model incorporating the size distribution of the feed suspension (Multi Size Group model), its diphasic nature (Schiller Naumann model) and the presence of turbulence (Shear Stress Transport model) has been solved numerically using ANSYS-CFX software. Preliminary results indicate that the overflow clarity is mainly controlled by lateral diffusion of fine particles (~20µm) from the exit of the feed well and by their upward transport from the sediment bed interface. Also the turbulence pattern in the settling zone seems to play a significant role in this vertical transportation. The validity of the model has been verified by comparing the measured solid concentrations from a pilot classifier with the calculated ones. This model could provide mineral processing plant operators and designers with a tool to optimize the configuration of classifiers with respect to the overflow clarity.INTRODUCTIONProblemIn the Bayer process, alumina hydrate precipitation from the saturated liquor is initiated in settler by adding crystallization seeds. Most of the precipitated alumina settles to the bottom of the tank while the liquor and the remaining alumina rise to the top, where they are removed at the overflow. Ideally the overflow clarity, which depends on the operational mode of the classifier, should be controlled within targeted limits."

Jan 1, 2016

By R. C. Gilmore, J. McMack, G. E. Bogin, J. F. Brune, C. DeRosa

"Researchers at the Colorado School of Mines are designing and building a 1:40 scaled physical model of a fully operational longwall coal mine. The purpose of the model is to minimize the occurrence of methane explosion hazards by testing various ventilation strategies and determining optimal methane sensor placement throughout the longwall face. Fluid scaling factors were analyzed using Computational Fluid Dynamics software Ansys FLUENT™ at both full and 1/40th scales. Researchers were able to identify key scaling factors and subsequently developed suitable flow parameters that would maintain full scale accuracy of flow patterns in the 1/40th model. KEYWORDS Coal, Longwall, Methane, Explosion, Scale Model, Ventilation, Fluid Dynamics, Richardson, Gob, Porous INTRODUCTION Mine ventilation systems are a key component for ensuring a safe working environment by introducing fresh air from the surface and diluting explosive gases and hazardous contaminants. This holds true for longwall coal mines where the emission of flammable methane gas from the longwall face as well as the gob can create explosive mixtures of methane and air. Therefore, an effective ventilation strategy can help mitigate the potential for accidents within a mine. Developing an effective mine ventilation system (MVS) requires a detailed understanding of the physics of gas transport and how this relates to specific geometries and obstructions in the face. Researching this phenomenon requires the development of computational fluid dynamics models capable of simulating fluid flow and methane species transport that can be validated through physical experimentation. Unique site conditions determine ventilation layouts for every coal mine. Researchers have designed a 1/40th scaled physical model of a longwall coal face and adjacent gob that includes movable shield supports and a movable shearer with rotating cutter drums that can be adjusted to a variety of ventilation conditions. The proposed work will address the need for an improved Mine-wide Atmospheric Monitoring System (AMS), and provide the ability to link existing MVS models with AMS in real time. By accurately representing the coal face, the gob area and the mining equipment, gate roads and bleeder entries, the scaled model accurately represents all relevant structures, geometry, and dynamic conditions. A Plexiglas cover allows full optical access for sensor equipment as well as visual inspection of the fluid flow and species transport."

Jan 1, 2019

By Adrian White

Agenda Overview of pastefill at Kidd Mine Pipeline wear and the need to monitor Steel Loop monitoring Steel Borehole monitoring Monitoring pipe linings

May 1, 2013

By Allan R. Punkkinen

Safe extraction of the valued ore resource in the deep levels of VALE Creighton Mine has progressed in a pillar-less fashion using vertical retreat, slot-slash and uppers retreat methods since the cessation of ?cut and fill? mining in the late 1980?s. Sequencing of the panel extraction and filling has been the key to successful exploitation of high stress orebodies at depth. In late 2010, discussions between the Operating Department and Creighton Ground Control revealed an opportunity to evaluate a trial primarysecondary sequence in the west end of the 400 Orebody at the 2340m horizon. To manage the trial primarysecondary project, a high level risk analysis and management of change was carried out to mitigate potential danger. As part of the requirements, an instrumentation project was conducted in the hanging wall and footwall bottomsills of the secondary panel and within the secondary panel itself. The extraction sequence was modeled with Map3D® software, confirming high stress levels with the advance of the primary panel. Enhanced ground support was installed based on modelling results. A key objective of the instrumentation project was to verify support system response to mining and to obtain knowledge in regards to the behavior of the stope. This paper describes the first time that this type of new innovative instrumented rockbolt technology had been used in a hard rock mining environment. Understanding of the physical deformation mechanisms of ground support in response to high stress conditions is the basis for an effective ground control strategy. The data played an important role in subsequent enhanced ground support system design at the mine and importantly, established the fact that the secondary pillar had not totally failed. Subsequent cavity monitor results helped establish that fact.

Jun 1, 2012

By C. J. Hall

This paper presents a basic motive column analysis of natural ventilation and shaft resistance, using the density depth diagram. The method makes use of tables showing the state of the air as determined by thermodynamic analysis. Several theoretical examples are given.

Jan 1, 1968

By D. Sbarbaro

In many modem concentrators the use of supervisory systems in their grinding circuits has meant more consistent operations and increases in capacity. These systems rely on a series of specific algorithms that uses different pieces of information and drives actions over the process. One of these algorithms is the ball mill overload detection, which plays an important role in any supervisory strategy designed to maximize ore feed rate in wet grinding circuits. This paper introduces different overload detection algorithms, and compares them in terms of the time taken to detect the overload condition. This comparative analysis is based on highly noisy power draw measurements obtained in an industrial plant.

Jan 1, 2007

By V. Polotski

This paper describes a platform for autonomous operations in open pit mining environments. A typical operation consists of: (1) Initial locomotion toward a remote worksite; (2) Pattern navigation within the worksite; (3) Worksite manipulations and (4) Return locomotion to the start location. The platform includes precise localization module based upon the fusion of odometry, inertial and GPS measurements. The guidance module starts from a set of way points specified on a GPSreferenced map and plans and executes the mission. A typical mission includes specified manipulative tasks along the navigation path. During motion execution the on-board system continuously verifies that the path is free of obstacles and that the hardware is not overloaded. Momentary losses of external positioning measurements does not adversely affect the performance, owing to the redundancy in position and heading estimation. A rehearsal phase follows planning and allows the supervisor to examine the kinematic behavior of the platform during motion, thus reducing the need for continuous monitoring during execution and providing protection against potential losses of communication.

May 1, 2003

By E. L. Martheleur

A general expression for the electric power generated or consumed in a direct-current circuit is obtained by multiplying the reading of a suitable voltmeter connected across the terminals by the reading of an ammeter connected in the circuit. by the reading of an ammeter connected in the circuit. When alternating currents are considered, the product of the volts and amperes as obtained for direct currents does not generally represent the true energy involved; it is greater than this true energy and should be multiplied by a certain factor which may have any value between zero and unity, according to the conditions of the circuit. This factor is called the power-factor of the system, and expresses the ratio of the true energy over the apparent energy. For a three-phase system the expression of the apparent energy is [\/ 3 x E x I; ] while the expression of the true energy, that is, energy suitable for mechanical work, is [v? 3 x E x I x cos A.] The total current of a circuit corresponds to the reading of an ammeter connected in the circuit; it is the resultant of two currents. The first of these is in phase with the voltage, and is that portion which really produces mechanical work; the second is always in quadrature with the voltage, that is it may lead or lag the voltage by 90° according to the condition of the circuit. This second current does not produce any sensible work, and for this reason is sometimes called wattless current or reactive current.

Jan 1, 1924

By Walker. P. W. A.

Abstract -The Riviera tungsten occurrence in the Cape Province of South Africa was discovered in October 1979 as a result of stream-sediment panned concentrate sampling. The Cape age granite and late Precambrian Malmesbury Group carbonates and chlorite schists which it intrudes and which host the mineralization are covered by between 10 m and 30 m of Tertiary/Recent alluvium and clay. The scheelite/powellite and molybdenite mineralization occurs in a greisenized granite cupola with an overprint of porphyry-type alteration as well as in minor skarns. The ore reserve is estimated to be 46 million tonnes at an average grade of 0.2160Jo W03 and 0.020% Mo. The deposit is uneconomic at current tungsten prices.

Jan 1, 1994

By J. D. Stewart

One of the first important questions that should be settled on the opening of a mine or the development of a new deep is the system of haulage to be used, since the layout of the haulage-ways at the pit bottom, or, in case of a slope mine, the arrangement of the surface works, depends largely upon the type selected. Should it later become desirable to install a system of haulage of a type other than that for which the mine roadways were originally laid out, considerable difficulty would likely be encountered in its installation and with the result that it would in all probability be most unsatisfactory and expensive in its operations. It therefore becomes very necessary that full consideration be given the haulage problem at an early date in order that the type best suited to the mine conditions and the required outputs can be intelligently planned for. It is sometimes found, however, that no matter how well the mining engineer explores the seam to be developed, or how accurately he anticipates its eccentricities, there will still remain some unrevealed or unsuspected conditions, or shall we say obstacles, placed by Nature to prevent the too easy winning of her treasures and incidentally to frustrate or modify the application of the plan so painstakingly laid down on paper, and to adversely affect the cost estimate.

Jan 1, 1928

By T. C. WEBB

In New Brunswick, significant potash deposits are intimately associated with rocks of the Lower Carboniferous Windsor Group. To date, two deposits high in sylvinite, up to 20 m thick, have been confirmed at depths between 490 and 1,035 m below surface near Plumweseep and Salt Springs. These areas are currently under development by the Potash Company of America and the Denison-Potacan Potash Company respectively. A third area, near Lower Millstream, is also known to contain potash-bearing evaporites and is now being explored by BP Exploration Canada Ltd. All three areas are situated in the western half of the Moncion Subbasin and are within 25 km of Sussex. Numerous similarities in stratigraphy, thickness, mineralogy and structure suggest that deposition of evaporites throughout much of southern New Brunswick was contemporaneous and extended over a considerable area. Future opportunities for potash exploration in the province thus seem excellent. A number of large unexplored areas remain in the Moncion and Cumberland Subbasins and in parts

Jan 1, 1984

By Charles S. Ney

"ZINC-LEAD REPLACEMENT deposits straddle the steep-sided valley of Kicking Horse River at a point three miles east of Field, B.c., in Yoho National Park. The Monarch orebodies extend into Mt. Stephen on the south side of the valley, and outcrop at two points, 1,000 and 1,200 feet above the valley floor. The Kicking Horse deposits are in Mt. Field, on the north side of the valley, and they outcrop 200 feet lower.The East Monarch outcrop is said to have been discovered in 1884 during construction of the Canadian Pacific Railway. The larger West Monarch outcrop, 700 feet west of the original discovery, was not reached till 1917 because of its nearly inaccessible location on the cliff face.The Kicking Horse mine was staked in 1906. Little development was done for several decades, and mining was not commenced till 1935.At the East Monarch, mining was commenced soon after location, and several thousand tons of ore were shipped prior to 1912. At this time a gravity concentrator was installed. This was operated till 1924, and a total of 42,000 tons of ore were mined, including about 10,000 tons from the West Monarch. The period from 1928 to 1935 featured flotation milling and the mining of 265,000 tons of ore, mostly from the West Monarch orebody. Intensive exploratory development was carried out in both Monarch and Kicking Horse from 1935 to 1946. Production from both mines in this period totalled 380,000 tons. From 1947 to the time of closure in 1952, considerable new ore was found in both mines and 185,000 tons were milled. Immediate possibilities for finding ore in the Monarch were considered exhausted. Kicking Horse orebodies are known to persist with a low grade of zinc. Total production from the two mines amounts to 842,500 tons grading approximately 7 per cent lead, 10 per cent zinc, and 1.2 ounces per ton silver."

Jan 1, 1949

By A. Gakwaya, P. Vachon-Joannette, P. Gagnon, J. Lévesque

"Predictive numerical methods are essential tools for reduced development cost and improved high performance designs of modern aircrafts. Their use leads to savings in terms of design cycle time and experimental trials. Composite materials subjected to impact loadings demonstrate various damage modes such as matrix cracking, fiber breakage, delamination and, ultimately, fabric fracture. Composite laminates are extensively used in the aerospace industry, and their damage modeling is complex due to their inhomogeneity and anisotropic behavior. Damage evolution affects both in-service properties and performance of these composites. In this work, the drop-weight impact test has been simulated. Using a material model that accounts for both delamination and intralaminar damage, laminates response is analysed using numerical simulations based on 3-D finite-element models of the commercial code Abaqus/Explicit. Experimental and simulation results are compared, in terms of energy absorption and contact force. The obtained numerical results show good agreement with experimental data.INTRODUCTIONAs primary aircraft structures are increasingly being made from advanced fiber-reinforced polymer matrix composites and are in general exposed to a variety of impact scenarios (bird, hail, debris etc.), an understanding of the impact event and the performance of composite materials during impact is important in the development of new structures. This work is focussed on low velocity impacts that typically occur when foreign objects hit the aircraft during maintenance or other on-the-ground operations. These impacts can cause non visible damage that affect the structural integrity of the composite components. While for metallic structures, damaging impact events typically leave noticeable dents due to plastic deformation, in contrast, for high strength carbon fiber reinforced composites, they can deform elastically to strain levels exceeding 1% and the internal damage can often occur without the formation of a visible dent. The identification and effect of impact damage on the performance of the structure is thus of great concern to the aircraft industry as the durability and damage tolerance of these composite structures are strongly influenced by the size of detectable internal damage."

Jan 1, 2016

The quality of refractory bricks and castables could be determined by direct measurements of their material properties such as elastic properties, porosity, density, etc. using conventional static or non-destructive testing (NDT) dynamic techniques. Quality monitoring of refractory linings is much more challenging and complicated. The static methods require undesirable drilling and sample extractions from the furnace structure. A more desirable alternative is the use of NDT techniques for material quality estimation. The Acousto Ultrasonic-Echo (AU-E) technique is a new stress wave propagation approach for monitoring the quality of refractory linings in operating furnaces. In this paper, the conceptual methodology for the AU-E technique is described, the capabilities and limitations are expanded, and the results from two case studies are discussed.

Jan 1, 2005

By L. Shasko, M. Hurlbert

As climate change is increasingly perceived as a problem, and fossil fuel based power production options are increasingly limited through regulatory restrictions and public distaste, future options become constricted. Reflexivity and social learning elicited through qualitative and mixed research methods offer important insight into what future power production pathways might be. Given factors of cost, baseload requirements, and energy density, options such as nuclear may be increasingly accepted. This paper explores this literature and possible methods of pursuing the reluctant acceptance of nuclear energy.

Jan 1, 2020

By Y. M. Shneerson, E. E. Zhmarin, E. M. Vigdorchik

One of the Gipronickel Institute activities is research and development of customized leaching technologies. The work is performed in several steps. Leaching kinetics are studied on a lab-scale according to a special procedure. Experimental data are processed using mathematical models of batch and continuous processes. Reliability of kinetic data and preliminary calculations is verified experimentally in laboratory reactors of various capacities. If necessary, certain parameters of the mathematical model are adjusted after pilot plant tests in continuous mode ( 4-reactor train, each with 25 L capacity). The specified kinetic characteristics along with the mathematical model are used for further development of industrial leaching technology.

Jan 1, 2005

By Chas. L. Emery

"The laws of rock mechanics apply equally well to all rock structures, and open pits are not exceptions. The concepts and some arguments about the emphasis to be placed on various aspects of open-pit design are discussed in this article.RocksROCK can be described as a granular material consisting of grains and glue. The grains may be fragments of other rocks or polycrystalline aggregates. The glue may be ferruginous, calcareous, argillaceous, siliceous or other material connecting the grains. In a crystal intergrowth, the outer layers of the crystals in contact with each other may be considered to act as a glue. Water may be a glue in clay or a grain in a crystal structure. Air and other fluids or gases are grains if they occupy spaces in a granular mass. Such grains are functional either chemically or mechanically or both."

Jan 1, 1966