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By James D. Bittner

Separation Technologies, LLC (ST) has developed a processing system based on triboelectric charging and electrostatic separation that provides the mineral processing industry a means to beneficiate fine materials with an entirely dry technology. The environmentally friendly process can eliminate wet processing and required drying of the final material. The process requires little if any pre-treatment of the material other than grinding and operates at high capacity ? up to 40 tonnes per hour by a compact machine. Energy consumption is low, approximately 1 kWh/tonne of material processed. Since the only potential emission of the process is dust, permitting is typically relatively easy. In contrast to the other available electrostatic separation processes that are typically limited to particles greater than 75 µm in size, the ST belt separator is ideally suited for separation of very fine (<1 µm) to moderately coarse (300 µm) materials with very high throughputs. The triboelectric particle charging is effective for a wide range of materials and only requires particle ? particle contact. The small gap, high electric field, counter current flow, vigorous particle-particle agitation and self-cleaning action of the belt on the electrodes are the critical features of the ST separator. The high efficiency multi-stage separation through charging / recharging and internal recycle results in far superior separations and is effective on fine materials that cannot be separated at all by the conventional electrostatic techniques. Since 1995, this triboelectric process has been extensively used for the beneficiation of coal fly ash with eighteen separators in place and over 130 machine-years of operation at locations in North America and Europe. ST has also installed separators for the beneficiation of industrial minerals in North America and Europe. The technology has been successfully applied to the beneficiation of a variety of minerals including calcium carbonates, talc, barite, and potash.

Aug 1, 2013

By Shuai-Jun Li, Xia-Ting Feng, Xian-Jie Hao

"The anisotropy of rock is of great importance to the rock engineering. To investigate the anisotropic character of slate, the rock samples of slate under different confining pressures and bedding plane angles was conducted on the MTS. The results indicated that the relationship between bedding plane angle and elasticity modulus, friction angle, cohesion and strength was shown as U pattern. The minimum value of them is located from 30°to 45°.In addition, the elasticity modulus and Poisson's ratio increase with the increasing confining pressure. The slate behaves brittle failure both in the uniaxial and triaxial compression. The failure pattern of uniaxial compression is generally tension failure, and triaxial test usually shows shear failure. The failure angle decrease with the increasing of confining pressure.INTRODUCTIONThe anisotropy of rock is that loading in different orientations the rock has different mechanical properties. The anisotropic property of rock is always an important problem in rock engineering (Hoek E. & Brown E. T., 1980). J. C. Jaeger (1960) first presented that transverse strength criterion for sliding fracture on joint surface. Later he revised rock parameters to anisotropy empirically for isotropic Mohr- Coulomb criterion. His main idea is revising cohesion according to loading direction (J. C. Jaeger, 1971). Then, many scholars study a lot on transverse strength criterion. E. Z. Lajtai (1969) considered the influence of connecting rate in all directions in joint groups for shear strength in intact rock; R. Mclamore and K. E. Gray (1967) referenced the theory of J. C. Jaeger. They not only revised cohesion also revised friction coefficient. Y. M. Tien (2000, 2001) made further study on the influence of connecting rate in joint group to transverse strength. R. Nova (1980) studied on the variation of strength when rock specimens in triaxial pressure and complex stress paths. O. Cazacu(1998) put forwards a new anisotropic strength criterion for analyzing rock strength. S. Pietruszczak(2000) introduced fabric tensor for characterizing inner seismic structure and he built an anisotropic strength criterion containing the invariants of stress tensor and seismic fabric tensor."

Jan 1, 2015

By P. Personnet, D. Wheaton, E. Couzinie, V. Demetriou, Brooks. W., G. Girault, M. Meyer, L. Charbonnel

A common problem in Gas Treatment Centers (GTC) from primary aluminium smelters is the temperature of the gas to be treated : above a threshold, filtering media are irreversibly damaged. The traditional way of dealing with high gas temperature is to dilute with fresh air, which implies over sizing - and therefore higher cost for - the GTC in order to have the capacity to treat this dilution air without compromising on pot suction. A system was developed which decreases gas temperature without having to use dilution air. This system is based on water pulverization in gas collectors. The water vaporization leads to a temperature decrease of the gas. A pilot system was trialed in our R&D unit. Satisfactory results led to the development of an industrial system based on Envirocare equipment (partnership), which was trialed in our production plant in Tomago (NSW, Australia). This patented system was then generalized in this plant, which is now using it with success during austral summer.

Jan 1, 2006

By John Steele

The goal of this project is to detect the presence of objects behind haul trucks and to provide an alarm to the driver if such objects are detected. Objects of interest include people, pickups, other equipment, and large rocks. Another goal is to see if the system can identify the existence of a berm and determine the distance from the truck to that berm, so a safe backup distance can be computed and used as a reference. This paper presents results that demonstrate that such a system is feasible and includes results from work at a local quarry. Architecture of the system is provided and the various subsystems are discussed. Details of the algorthims are included and discussion of the issues involved in developing a fieldable system are also included.

May 1, 2003

By O. F. Carter

"Coniaurum Mines, Limited, hold nineteen claims in Tisdale township, in the Porcupine district, adjoining the McIntyre mine on the east. They extend for over a mile along the strike of the Hollinger-McIntyre 'break'. The property has been explored extensively along the ore zone both laterally and vertically. Workings have been carried to a depth of 5,500 feet, and nearly 50 miles of lateral workings (drifting and cross-cutting) have been driven to date in development and in gaining access to the orebodies.Production started at the Coniaurum in June 1928 and has continued without interruption. To the end of 1946 the plant has treated 2,695,725 tons of ore, yielding gold having a value of $21,989,918.The Coniaurum is controlled by Ventures Limited of Toronto. Mr. John Redington, who has guided all operations since work began on the property in 1922, is Managing Director.GENERAL GEOLOGYAge and Types of RocksKeweenawan- Quartz diabase dykes.Algoman - Quartz porphyry intrusive; the veins are probably late Algoman.Keewatin - Lava flows.Brief Description of Rock Types.Diabase DykesTwo quartz diabase dykes traverse the property in a north-south direction, cutting all formations, including veins.Porphyry IntrusivePetrographically all porphyries in the Coniaurum are of the usual Porcupine type- quartz-feldspar with alteration advanced in most instances to the stage where the feldspars are completely dissolved, leaving a wellsheared carbonate and sericite matrix with embedded rounded quartz 'eyes'. Alteration is most extensive in the smaller bodies and in the narrow protuberances from the larger masses; the cores of the larger masses are generally much fresher, with more or less well defined feldspar phenocrysts."

Jan 1, 1954

By K. E. Waters, N. Brodusch, R. Gauvin, H. Demers

"Rare earth elements are becoming increasingly in demand, due to their prevalence in both renewable energy devices and high-end electronics. The characterization of the composition, morphology and volume fraction of the various phases that have valuable rare earths in the ores are needed to find the optimal industrial process to extract the ores containing the rare earths. Rare earth-bearing minerals contain many elements with the M-and L-lines overlap, requiring a high degree of resolution, pushing the boundaries of scanning electron microscopy quantitative analysis. Enhanced microscopy at a high spatial resolution with improved x-ray quantitative analysis enables the accurate determination of the distribution of the desired rare earths in various mineral phases. INTRODUCTIONRare earth elements are becoming increasingly in demand, due to their prevalence in both renewable energy devices and high-end electronics. From batteries (lanthanum and cerium), to magnets (dysprosium and neodymium) and lighting (yttrium), the rare earth elements are crucial to the advancement of technology, and to energy saving devices (Crow, 2011). The goal of this project is to characterize the composition, morphology and volume fraction of the various phases that have valuable rare earths in the ores in order to estimate the economical VALUES (of the ores and to find the optimal industrial process to extract the ores containing the rare earths. High spatial resolution imaging and x-ray microanalysis are needed to reach this goal. In this work, the results obtained with a cold-field-emission scanning electron microscope (FE-SEM) and a silicon drift detector (SDD) energy dispersive spectrometry (EDS) detector at low accelerating voltage are compared to experimental conditions typically used with electron probe microanalysis (EPMA) instrument.With this improvement, a detailed scientific analysis of the composition of these, and other, ores will become possible with a SEM/EDS system. This will help to better understand how such ores were formed, hence assisting in finding them, and to better understand how to process them in preparation for high end industrial applications, namely through mineral processing."

Jan 1, 2012

By Yin Wang, Lin Li, Zhongwei Bi, Like Wei, Wen Li, Shaogang Li, Bin Zhang, Hongjie Li

Presently,Many long-wall fully-mechanized faces in shallow depth coal seams are below room and pillar goaf in Shendong mining area. When the working face is advanced out of concentrated coal pillar in upper room and pillar goaf, strong strata behaviors often cause support crushing accident. Aiming at a support crushing accident which happened in Shigetai coal mine of Shenhua group in Shendong mining area, this paper analyses the stress transfer process while mining out of concentrated coal pillar by numerical simulation software FLAC3D. According to the feature, simplifying the roof of upper room and pillar goaf as supporting-beam structure explains mechanism of large area collapse in room and pillar goaf roof. Based on the feature of supporting-beam structure, deep-hole blasting concentrated coal pillar technology is proposed to control the strong strata behaviors in Shigetai coal mine. The blasting control effect is confirmed through characteristics of strata behaviors, growth circumstance of ground crack and multi-point extensometer monitoring results. By using control technology, Shigetai coal mine has been successfully avoided support crushing accident.

Jan 1, 2015

By C. H. Sleeman

"The Iron Ore Company of Canada constructed a beneficiation complex in Sept-Iles, Quebec, to concentrate and pelletize earthy red hematite iron ores from the Knob Lake area. The plants were scheduled for initial production during the first quarter of 1973.Many problems have been experienced to date. Difficulties in controlling the process, excessive mechanical failures, design deficiencies and manpower-staffing problems have caused an extended start-up. The problems are now essentially solved and, with the completion of some additional minor modifications, it is expected that the plants will be producing premium iron ore pellets at or near rated capacity within the next immediate period."

Jan 1, 1976

By A. C. Stevenson

"The most common theory is that, since thyristors, diodes, and insulated gate bipolar transistors (IGBTs) are “solid state” they will live forever. This is not so. They have wear-out mechanisms (e.g. insulation) and other mechanical parts such as motor bearings. These wear-out phenomena can be easily calculated. In this paper we will look at some of the failures and the failure rate of thyristors in power converters to see what affects them and to see what improvements can be made. If converter failures do occur, some simple forensic engineering steps will show if this is the root cause of the problem.IntroductionLook at the general failure rate curve for thyristors, diodes, gate turn off devices (GTOs) and IGBTs shown in Figure 1. We see that there is an initial high failure rate due to manufacturing defects, application problems, and drive start-up stresses that lasts for a few weeks. This is followed by a long period of (hopefully) several years with a relatively low but very slowly rising failure rate. At the end of this period, the devices start to wear out and the failure rate suddenly starts to increase rapidly over a few months. This signals the end of life for the devices in the system. We will start by looking at this end of life area."

Jan 1, 2000

By Samuel O. Akande

"Gold occurs as native metal, in electrum, and in a telluride mineral in quartz carbonate veinlets of three vein systems at the Ross Mine, northern Ontario. The 14 Vein System is made up predominantly of concordant veinlets within layered ankeritic dolomite stratabound by, and conformable with, andesite tuff Individual veinlets contain pyrite, sphalerite, galena, chalcopyrite, tennantite, pearceite, proustite, native gold and electrum in a matrix of quartz, dolomite, ankerite and calcite. The 2B Vein System is made up of both concordant and discordant veinlets within andesite tuffs. The veinlets contain pyrite, chalcopyrite, sphalerite, bornite, tennantite and free gold in quartz, calcite and dolomite. The 18 Vein System is comprised of stockwork veinlets in and around intrusive syenite which has both sharp and gradational contacts with enclosing andesite tuff The veinlets contain pyrite, chalcopyrite, bornite, chalcocite, native gold and calaverite. Sulphide and silicate minerals in veinlets and wall rocks are stable assemblages for the regional metamorphism of greenschist rank. ,The 14 Vein System is interpreted as a metalliferous siliceous carbonate chemical sediment, the components of which were leached from the underlying volcanic rocks by convecting sea water and subsequently deposited on the sea floor between the extrusion of flows and pyroclastic rocks. Subsequent regional metamorphism and intrusions remobilized and redistributed the syngenetic stratabound material into dilatant fractures in adjacent tuff, as in the 2B and the 18 vein systems."

Jan 1, 1982

By S. Harshaw, C. Doyle, A. E. M. Warner, D. Stremlaw

"In the Utility Nickel furnaces, the hearth and sidewalls are lined with high-Al2O3 bricks. During charging and thermal cycling (more so as the linings on these reverberatory furnaces age), pieces of brick spall or abrade from the refractory and collect on the top of the bath. These pieces are removed using a non-corrosive slag toward the end of the heat when the bath temperature is ~1600°C.This benign liquid can be generated by two methods. First and most obvious, suitable ingredients can be pre-mixed so that the flux (flux A) is isochemical with the non-corrosive slag. All that is needed to produce this targetted slag is heat. Second, in other proportions (flux B), the pre-mixed ingredients generate a corrosive slag that melts completely at -1200 °C and corrodes some but not all of the brick particles on the bath surface. As the reaction progresses, the slag changes composition eventually attaining the targetted benign composition. Using this option, additions are monitored to avoid overfluxing. In both cases, the generated slag/brick mixture can then be rabbled from the furnace. This practice has been successfully used for over two years and has been a factor in extending Utility Nickel furnace life to its current levels (about25% increase)."

Jan 1, 1993

By JOHN DUNFIELD

Good quality sphagnum peat bogs occur across Canada in areas of ample rainfall and cool, temperate climates. Early peat production techniques were restricted primarily to hand digging blocks of peat and piling them up to be dried by sun and wind. Suburban de velopment in the 1950s and the concomitant spread of home gardening triggered a dramatic growth in peat demand; labour costs rose in the same period. Peat production techniques had to alter accordingly. The three mechanical inno vations attempted were hydraulic mining, mechanical block digging and vacuum harvesting. Of these, the last method pro ved the most successful in Canada and is used to harvest 80% of Canadian peat production. Escalating transportation costs are the most important feature affecting future development of the Canadian peat industry.

Jan 1, 1984

By G. S. Barry

INVESTIGATIONS to date have shown that, should there be the need or the appropriate economic stimulus, Canada&apos;s mineral resources are sufficiently extensive to allow considerable expansion of its non-fuel mineral industry, during the remaining part of this century and possibly beyond (1, 2). The availability of sufficient capital will be one of the critical factors which will determine whether this potential will be fulfilled. The following analysis centers on the capital requirements of the Canadian non-fuel mineral industry under one set of basic assumptions of capacity growth, cost of new and replacement capacity, rates of depletion and depreciation of mines and plant, and the cost of exploration and infrastructure. Mindful of the fact that exploration and development will not thrive in Canada unless a very positive approach is taken, the writers make no apologies for being "optimistic" about long-term production prospects. Furthermore, in the event that world demand does escalate as anticipated and the forecast realistically attainable levels of Canadian production are not reached, then Canada will not have reaped the full range of economic benefits available, and opportunities will have been lost. Projections for Canadian production between 1976 and 2000 are essentially based on the forecast published in the 1974 paper, "Towards a Mineral Policy for Canada - Opportunities for Choice (3), with some updating on the basis of recent developments.

Jan 1, 1977

This paper outlines the position and capabilities of Western Canada&apos;s bituminous coal industry, and indicates the increasing importance of Japan as an export market. The use of coal in Japan is reviewed, especially as regards future trends, and an appraisal is made of Canadian coal in comparison with domestic Japanese coal and imports from other countries. The importance of maintaining a solid nucleous within the Canadian bituminous coal industry is emphasized. I N RECENT years, Japan has emerged as a valuable market for Canadian exports. The first major product exported in volume to Japan was wheat, which has become very successfully established in Japanese markets. Following this, iron ore gradually found a market in Japan, with exports usually based on long-term contracts. This iron ore was produced entirely in British Columbia In 1958, the Western Canadian bituminous coal industry -jointly with the Dominion Coal Board -sent an official mission to Japan to investigate the

Jan 1, 1964

By Lin-fang Shen, Shao-jun Li, Zhi-liang Wang

"The meso-structure of real soil consists of numerous particles with different sizes, while the traditional reconstruction method of quartet structure generation set (QSGS) produce relatively uniform soil particles resulting in significant discrepancy between the actual structure and reconfiguration model. In order to remedy the deficiency, the QSGS is improved by considering the influence of porosity and autocorrelative function of soil, which make the models closer to the real soil. Based on the reconfiguration model, Lattice Boltzmann method is combined in the algorithm to conduct further simulation of fluid flow in soil pores. The D2Q9 model is applied to construct the two dimensional model for simulating mesoscopic seepage field of saturated soil by setting the non-equilibrium extrapolation scheme at the inlet and outlet boundary, and the bounce-back scheme at the soil particles boundary as well as the left and right boundary. According to the case study, the proposed program is realized to simulate mesoscopic seepage field of reconstructed soil with constant inlet seepage velocity. The results show that the seepage direction of soil is along the passage with good connectivity, therefore the permeability is controlled by these passages. The seepage velocity in such channels is faster than in bad connectivity channels. Even if the channel has larger pores, the seepage velocity is still small. INTRODUCTIONUnderstanding the seepage mechanism in porous materials is significant in both theoretical and engineering problems. As a typical porous media, soil consists of solid particles and voids, which form connected channels allowing water to flow through. Such seepage in soil exists widely among geotechnical project of slope, foundation pit, and tunnel, etc. Meanwhile, a number of engineering accidents are caused by limited knowledge of seepage characters in soil (Huang, 2006; Liu, 2013). The conventional method in describing seepage features mostly based on the parameter of permeability, which is a macro statistic mean evaluating the whole connectivity of soil. Obviously, this parameter cannot exactly reflect the details of how water flows through the inner soil structure, especially the flow velocity in local mesoscopic area, hence is unable to represent the actual seepage properties. Therefore, it is necessary to develop mesoscopic approaches to fully study the seepage mechanisms."

Jan 1, 2015

By P. Cavanagh

Summary This paper discusses the fundamental principles which allow the development of a new method for studying the deformation and failure of metals in terms of &apos;internal microstrains&apos;. Internal microstrains mechanical and magnetic properties are defined and their influence on of metals is outlined. A research programme at present in progress will determine whether magnetic measurements of internal microstrains give sufficiently accurate values for predicting the performance of metals under service conditions. These magnetic test techniques are also being used to detect the beginning of plastic deformation and to trace the development of deformation processes and failure. Results of the experimental work in each field will be published. Introduction Any attempts are being made to develop a complete theory embracing the mechanical behaviour of metals. In spite of the amount of experimental data available, the theoretical approach is rather difficult, since most of the mechanical properties of a metal are determined by deviations from the pure chemical composition or the perfect crystal. Both types of deviation are difficult to reproduce experimentally and to describe theoretically. In general, there are three main avenues of approach to the problem being followed today.

Jan 1, 1950

By R. P. Charbonnier

"To understand the operation of jigs and other separating processes based on differences in gravity, it is desirable to analyse the motion of various particles in given media under specific conditions. A summary of the earlier theories shows that they lead to unsatisfactory or excessively complicated formulae in cases such as coal jigging. By adopting a simplified theory of the motion of particles in a fluid, the size and duration of the initial accelerated motion of a particle falling in hindered settling can be calculated. Based on this mathematical analysis, examples referring to actual coal jigging practice show that it is desirable to prolong and/or repeat, as frequently as possible, the optimum conditions corresponding to an effective acceleration of the particles. The separation is then obtained according to gravity rather than to particle dimensions, as would be the case if the velocity of the particles• were allowed to approach its terminal value. To achieve this gravity separation, it is suggested that the suction phase of the jigging cycle be artificially prolonged and the frequency of pulsations increased as much as possible for washing the coals of smaller sizes."

Jan 1, 1959

By M. Kowalczyk

The successful application of color sorting machines has established sensor-based sorting in the mineral industry in recent years and is considered today as a significant innovation in processing technology. However, we are only at the beginning of the (market) introduction. New sensor systems have been developed, which exploit material properties such as electrical conductivity, magnetization, molecular structure, thermal conductivity etc. This opens up new exciting pre-concentration and upgrading possibilities for many applications such as nickel, gold, copper and other ores as well as for industrial minerals, diamonds and other gemstones.

Jan 1, 2009

By H. A. Steane

THIS PAPER describes the re-grind section in the 2,000-ton per day, lead-zinc flotation mill of Canadian Exploration Limited, near Salmo, B.C. There are two re-grind units in operation, one in the lead circuit, and one in the zinc circuit. In each unit, the rougher concentrate is re-ground ahead of the cleaning circuit. These re-grind units have made valuable improvements in the concentrate grade, and with no loss in recovery by over-grinding galena or sphalerite. Since the initial installation of this re-grind section, the plant throughput has been increased gradually from 1,600 tons to 2,000 tons per twenty-four hours, and, as shown by the screen analysis of mill tailing, a coarser overall grind has been accepted, from 55 per cent to 45 per ?cent minus 200 mesh. There has been no increase in grinding capacity, but two mills have been taken from the main grinding circuit and used for the re-grind circuit.

Jan 1, 1958

By Daniel Torres Espinoza, Jose Pinedo

"Ventilation is a vital service in underground mines, required to provide fresh air to the work force and dilute diesel equipment gases (CO, NOx) and diesel particulate matters (DPM). At a Mexican precious metal mine in the state of Chihuahua there is a VOD system implemented using Howden’s control and monitoring system and a state of the art tagging and tracking technology. The JM zone of the mine is ventilated using a push and pull system, using automated regulators on each level to control the air going in and out of the levels. The implementation of advanced control strategies using Howden’s VentSim™CONTROL allows the mine to generate significant savings and increase health and safety of the workers.INTRODUCTIONIn underground mines, ventilation is a requirement in order to maintain the fresh air needed for personnel and equipment. Ventilation regulations dictate the amount of air required underground to carry out day to day operations by limiting the exposure that workers have to toxic gases and other pollutants. Regulations for required airflow in underground operations for diesel pollutants are generally provided on vehicle rated brake horsepower, in Mexico the requirement is 75 cfm/bhp. In underground mines, ventilation services can account to up to 75% of the mine’s energy consumption, and it is very common for fans to operate all the time because of a lack of control infrastructure for the ventilation system. By the implementation of a Ventilation On Demand (VOD) system a mine can reduce this consumption with different control strategies. The main infrastructure required to implement this system consists of remote control of ventilation infrastructure (fans and regulators), a communication network between throughout the mine with the surface and a tracking system for personnel and diesel equipment. Software is required to determine fresh air requirements based on the tracking system data and then send the control commands to the different ventilation infrastructure. In 2015, San Julian Mine acquired Howden’s VentSim™CONTROL (formally SmartEXEC) and the hardware solution to deploy a VOD system at their operation. The VOD system and Fresnillo plc’s San Julian Mine in Chihuahua, Mexico, consists of control of 10 surface exhaust fans, 2 surface intake fans, and 12 underground automated regulators. It also includes the monitoring of 46 flow sensors, 28 CO sensors, 28 NO?? sensors and 42 temperature and humidity sensors, approximately 500 personnel tags, approximately 220 vehicle tracking tags with diesel status (ON or OFF) and approximately 250 tracking zones. This paper discusses the control strategies that have been implemented at San Julian Mine since the system was commissioned and the next steps that will be taken at the mine with the system as they test different level on VOD."

Jan 1, 2019