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By Michael D. Justason

"In January 2009, long-time competitors, Anchor Shoring & Caissons Ltd. of Toronto and Bermingham Foundation Solutions of Hamilton, joined forces to tackle one of the Greater Toronto area’s largest deep foundation projects: the West Toronto Diamond Rail Grade Separation. The two companies formed the “West Diamond JV” and succeeded in winning the contract from the Canadian National Railways. This deep foundations work was the first and most significant part of the $300-million-plus rail grade separation project. A big part of the job turned out to be dealing with local government regulations and citizens’ concerns with noise and vibration.The project is approximately 10 km (6 mi) northwest of downtown Toronto in an area of mixed-zoning including light industrial, commercial and residential buildings. The area is commonly called the “The Junction,” because of the heavy rail- traffic. The “West Toronto Diamond” refers more specifically to the railway junction where the North-South tracks of Canadian National (CN) Railway meet at a level crossing with the East-West tracks of the Canadian Pacific (CP) Railway. The goal for this part of the project was to convert the West Toronto Diamond into a grade-separated junction by depressing the CN lines under the CP lines, thus allowing commuter rail carrier, called GO Transit, intercity carrier VIA Rail, and CN freight trains to pass through the new underpass.Dawn Tattle, president of Anchor Shoring & Caissons says, “not only is the site in a densely populated area adjacent to homes and businesses, the crews worked adjacent to active rail lines with numerous trains passing daily. During the 7-hour working day, approximately 60 trains passed through the site in very close proximity to working crews.” Safety was paramount. While trains were passing through the site, it was a railroad requirement that all equipment and men stop working. In addition, at those times, all personnel were required to stay 6 m (20 ft) from the tracks and were required to face the tracks. For the faster commuter trains, this work interruption could last as little as 2-3 minutes, while interruptions caused by the slower freight trains could last as long as 25 minutes. The most disruption to the site occurred during the morning commute between 7 to 9 a.m., so work did not really get underway until after that time. Once work finally commenced the race was on to finish as much as possible before the afternoon commute – hence the shortened work day. The amount of disruption caused by the trains was a big unknown faced by the JV going into the project, but crews adapted quickly to the very unusual work environment"

Jan 1, 2012

By Yi Luo

Multiple-seam mining operations induce surface subsidence basins different from those caused by mining in a single coal seam, and also disturb the mining operations in the other coal seams. A computer program, CISPM-MS (Comprehensive and Integrated Subsidence Prediction Model for Multiple Seam Mining), has been developed to predict the final surface movements and deformations as well as the interactions associated with multi-seam coal mining operations. The program applies a newly developed subsurface subsidence prediction model that is able to consider the geological stratification variations. In predicting surface subsidence, the surface movements and deformations caused by the individual mining operations as well as the interactive effects are all considered. A case study is conducted in this paper for validating the program.

Jan 1, 2012

By E. Bakhtavar

All parameters influencing the decision for selection of a suitable extraction method were first selected as the base of this study. Then these parameters were categorized in two main groups. The first group of the parameters includes ?geomechanical and inherent characteristics of the dimension stones? such as hardness, RQD, compressive strength, joints plane orientation and spacing, and water content. The second group was named ?technical and economical parameters associated with the investor?s objectives? like for example extraction capacity (production rate), blocks recovery, mechanization, capital investment and operational costs. Finally, the influences of all mentioned parameters on the selection of the most applicable extraction methods have been assessed and discussed.

Jan 1, 2012

By Alejandro R. Alonso, Lizet Alvarado, Gretchen T. Lapidus

"Cobalt and lithium recovery from spent Li-ion secondary batteries has been increasingly studied in recent years due to the high value of both metals and the low proven reserves for lithium. The standard method employed until now has been the deactivation and crushing of the batteries, followed by leaching of the L1C0O2 spinel from the battery cathode using acid solutions, such as 1.5 to 2.0 M HC1 or H2SO4, in a temperature range from 120°C to 250°C. Once leached, the cobalt is separated by electrodeposition and the lithium by precipitation, using large amounts of carbonate to bring the solution to alkaline pH values. In the present work, citric-thiosulfate solutions are used for the spinel leach at room temperature, favoring a reductive environment at room temperature, which stabilizes the cobalt(II) as cobalt citrate and lithium(I) at pH 5, and recovers approximately 99% of both metals.IntroductionThe Li-ion batteries industry has become an important economic sector in recent years. This type of battery is the most promising system for energy storage, because of its high efficiency in charge-discharge cycles, and its adaptability to many configurations. The demand will probably increase because of the need for mobile energy sources in many types of devices ranging from cell phones, tablets, and laptops to medical, navigation and sophisticated communication equipment and even in automobiles.One major problem related to the use of these batteries is the method employed for recycling the components, mostly cobalt and lithium. Currently, there are two processes employed on an industrial scale: the Sony/Sumimoto process, used since 1990 [1] and the Toxco Process [2]. In the first case, incineration is used to open the batteries and at same time volatilize the organic solvents. After that, the metals (copper, iron and aluminum) are physically separated. The cobalt and lithium are recovered as oxides and then thermally treated in order to recycle them for new batteries manufacture."

Jan 1, 2012

By J. R. Kish, J. Dabrowski

"The susceptibility to intergranular corrosion modes is a major technical issue preventing widespread utilization of higher strength welded AA7xxx extruded beam profiles, in the peak-aged T6 condition, in automotive bumper assemblies. A study was undertaken to evaluate the relative exfoliation corrosion resistance (ASTM G85-A2) as a function of joint design parameters, namely the base alloy composition, heat-treated condition and beam orientation after exposure to a cyclic acidified salt spray test. This paper documents the major findings extracted from this study.INTRODUCTIONBumper systems play a predominant role in the passive safety of an automobile, since they are one of the main structures for absorbing the collision energy in the event of an automobile crash. Heattreatable AA6xxx-series (Al-Mg-Si) and AA7xxx-series (Al-Zn-Mg) Al alloys, with relatively high strength, toughness, energy absorption, weldability and formability, make it possible to design costcompetitive bumper systems to crush in a controlled fashion. In this context, Cu-lean AA7xxx extrusions, such as AA7003 and AA7108, which exhibit higher strength than AA6xxx extrusion, such as AA6082, represent an attractive light weight material from which to fabricate bumper assemblies (Clausen et al., 2000; Pedersen et al., 2008; Chen et al., 2009).Arc welding is a key joining process for AA7xxx alloys within the transportation industry. A major technological issue preventing widespread utilization of arc-welded AA7xxx joints is the susceptibility to severe localized corrosion (Kent, 1970, Reboul et al., 1985; Holroyd et al., 1987). It generally occurs as exfoliation corrosion within a heat affected zone (HAZ) a few millimeters from the weld bead, or a type of stress corrosion cracking (weld-toe cracking), which initiates at the weld toe and propagates into the interfacial region between the weld bead and the HAZ (so called “white zone”). In addition to the micro-galvanic cell activity induced by the intermetallic compound constituent and strengthening particles present, there is strong evidence that macro-galvanic cell activity between the weld bead and base AA7xxx alloy may be playing a controlling role. Electrochemical profiles taken across fusion welded joints, in cross-section, during exposure to saline solutions suggest that a significant potential difference exists across the AA7xxx arc-welded joint (Shumaker et al., 1967; Grauer and Wiedmer, 1980; Tuck, 1985, Onoro and Ranninger, 1993). These studies consistently show that the HAZ and base alloy are more electronegative with respect to the weld bead (arc-welded with AA5xxx filler wire). Despite this initial important work, the majority of the recent corrosion research effort on welded AA7xxx alloys has focused on the performance of friction stir welds (Lumsden et al., 1999; Wadeson et al., 2006; Hatamleh et al., 2009)."

Jan 1, 2012

By Takahiko Okura, Satoshi Okano, Hiromichi Takebe

"Fine zinc concentrates tend to become sticky when roasted in a fluidized-bed reactor. The oxidation of high-purity ZnS powders and ZnS concentrates with different particle sizes were studied in terms of phase changes and particle morphologies. The sample materials were directly oxidized to ZnO in a roasting process performed over 700°C. Zinc oxide particles with diameters less than 0.5 ìðé formed at 700°C; the particle size increased by grain growth at 900°C. The coarse ZnS concentrate formed the oxysulfate ZnO2ZnS04 when roasted at 700°C; the sulfate transformed to ZnO at higher temperature.1. IntroductionRoasting is an important step in zinc extractive metallurgy because more than 80% of the world's zinc is produced from zinc sulfide concentrates using the roast-leach-electrowinning [1,2]. Currently, zinc concentrates with a finer particle size distribution are used to enhance recovery rate. However, the finer zinc concentrates tend to produce a sticky calcine in a fluidized-bed roaster [3].The factors that affect products in a fluidized-bed roaster include particle size, contaminant, O2 and SO2 partial pressures, and the feeding method of ore to the roaster. This study examined roasting behavior of high-purity ZnS powders and ZnS concentrates with different particle sizes. The phase changes and particle morphologies of the calcine samples producted from theZnS powders were studied."

Jan 1, 2012

By Anand Kumar, Pradeep kumar Jha, Suman Kant, Pradeep Kumar

"It has been a major challenge to reduce the intermixed grade formation during ladle change-over operation in continuous casting process of tundish steelmaking. The F-curve generated by step input of the tracer (new grade steel) tells about the intermixed grade amount for different grade specifications. Use of flow modifiers is beneficial in reducing the intermixed grade because of the change in slope (in different time zones) and position of the F-curve due to their placement at tundish bottom. Present study aims at investigating the role of dam placed before the outlet in a multi-strand tundish with reference to the slope behavior of F-curve in different time zones during the teeming operation plays an important role in determining the intermixed amount.Introduction In Continuous casting process, the old grade steel remaining in the tundish (reservoir between ladle and mould) from the old ladle gets mixed with new grade steel from new ladle and leads to intermixed grade which is considered to be of inferior quality. Although formation of intermixed grade is inevitable with the sequential method of casting, its amount can be controlled by changing the flow behavior of steel inside the steel. Intermixing in a slab caster tundish was simulated using 3-D numerical model based on k-å turbulence equation and compared their result with that of water model experiment Yeh and Hwang [1]. Huang and Thomas [2] reported that quantity of residual fluid in tundish affects the composition distribution in the transitional slab and thus the intermixed length. Huang and Thomas [3] developed three sub models to predict mixing in tundish, liquid core of strand and solidification. Thomas [4] developed a one dimensional model to simulate the final composition distributions in slab caster of continuous casting and investigated the effect of process variables on the intermixing. Alizadeh mehdi et al., [5] simulated of the intermixing phenomenon for slab casting for three different sub models. Goldschmidt et al. [6] developed a numerical model that predicted the location of the intermixed steel in a four line round caster. Lan and Khodadadi [7] studied for the transient fluid flow of liquid steel, heat transfer and solidification during the flying tundish change process. Cho and Kim [8] developed a mixing model to predict the outlet concentration of the tundish during grade transition. Most of the work reported in the literature has dealt with intermixing in slab caster tundish. Billet caster units are more often being used by steel industries due to growing demand of billets. The multiple outlets lead to varying degree of intermixing with time owing to their different distance (location) from the inlet. Use of flow modifier to minimize the intermixed amount, however has also not been discussed in detail so far. Further no work has been reported regarding effect of slope of F-curves obtained through different outlets on intermixing. Hence keeping these objectives in mind attempt has been made by authors to analyze the slope of Fcurves after dividing them into three different time zones and the effect of these time zones on intermixing."

Jan 1, 2012

By D. Sanguinetti, A. Consigny, M. Nodwell

"Alkali precipitation of dissolved metals is an inexpensive but non-selective means of treating mine wastewater. Alternatively, sulphide precipitation can treat to below parts-per-million concentrations while selectively recovering valuable metals. While technically feasible, sulphide treatment of dilute waste streams increases the size and cost of the plant relative to the metals loading. Ion exchange has been applied at two separate sites to pre-concentrate nickel containing wastewater prior to recovery in smaller and more cost effective sulphide precipitation circuits. The result is a dual-circuit system that can maintain high selectivity and reduce overall facility cost while meeting strict effluent regulations.INTRODUCTIONAlkali precipitation using lime is the most common method of treating mining effluents for dissolved metals removal. This method is generally sufficient for waste streams containing mixed metals of little value, and for meeting modest metal concentration limits in the final effluent. Due to the non-selective nature of the lime process, the produced metal hydroxide sludge is of little value. All metals are removed together in a sludge product which cannot be re-processed for further value recovery.By contrast, sulphide precipitation can be used to selectively remove and recover valuable base metals (such as copper, zinc, nickel and cobalt), since the sulphide will preferentially target these metals without reacting with less valuable metals (such as iron and aluminum). The low solubility of the metal sulphide solids also supports the removal of base metals to lower concentrations than can be achieved with alkali precipitation in addition to other benefits discussed more fully in a prior paper (Bratty, Lawrence, Kratochvil & Marchant, 2006). The corollary to this solubility feature is that sulphide precipitation can function on influent streams containing low (< 10 mg/L) metals concentrations to meet very low parts-perbillion final effluent concentrations. Reagent overdosing is also minimized when compared to alkali precipitation."

Jan 1, 2012

The global mining industry will always face significant challenges. Some, though, are bigger than others. What do you consider the major challenges facing the mining industry as a whole and SME in particular? Without a doubt, the major issue in both coal and metal/nonmetal mining industries is the ?graying? of the workforce in all aspects of mining. As the baby boomers continue to age, valuable experience is being lost by industry, government and academia. And there is the potential for SME to lose some of its membership. Now with that said, I should note that, despite the aging of the workforce, SME membership continued to grow by 7.1 percent during 2011.

Jan 1, 2012

By Fabio Mielli

Encompassing between 20 and 40 percent of the typical mining operational costs, energy in mining operations is a growing concern for the industry. However, this concern is a complex, multi-faceted variable that involves government regulations, societal pressures, cost and competitiveness. Managing energy efficiency is becoming a keystone of successful companies. The suggested energy strategy in mining and mineral processing operations must follow a well-structured approach to include the following: ? Understanding where energy is being used and why. ? Recommending and implementing energy conservation measures. ? Driving visibility to targets and results. ? Leveraging the energy spent across the enterprise. ? Developing a robust energy and sustainability strategy. Additionally, it must ensure that all decisions support the financial and operational integrity of the business.

Jan 1, 2012

By Björn Hinzel, Joachim Rösler

"The most important characteristic of open-pored metals is porosity, since it enables all of their functional applications as filters or sound absorbers. Due to the notch effect of the pores, mechanical properties of porous metals are better than the ones of comparable structures made of polymers or ceramics. Consequently, only open-pored metals can be used in aircrafts to reduce flow noise or noise resulting from the core engine by acoustic absorption. Absorption properties depend highly on pore size and porosity of the material, which must be characterized as precisely as possible in order to analyze the correlation between morphology and noise reduction performance. Here, a line segmenting method is explained in order to characterize pore size and porosity of absorber materials using image processing based on two dimensional microscopy images, including sample preparation and specification of the set-up. Then, the influence of the pore structure on the measured absorption behavior is discussed. Finally, the correlation of acoustic behavior, pore morphology, and porosity is outlined.IntroductionSignificant noise loads affect everyone causing anxiety, depression, insomnia and other effects which impair health and productivity [1],[2]. Due to the rising number of flights and aircrafts, air traffic noise increases dramatically. To counter this development, various approaches have been developed to reduce the different noise sources resulting from airframe, jet or engine [3],[4],[5],[6]. One approach to reduce this noise is the application of noise reducing liners in the hot gas path [7]. This is especially important, since the engine is becoming the dominant noise source of modern airplanes during take-off [8]. Due to the elevated temperatures and high fatigue loading in this part of the aero-engine, conventional passive absorber materials cannot be used. Polymers would not be able to bear the heat and ceramic fibers would crack under the mechanical loading due to the notch effect. Consequently, this study focuses on metals with open pores, which can resist elevated temperatures and fatigue loading and additionally resemble geometrically conventional passive absorbers. Based on the production processes, e.g. sintering of metal fibers [7], powder processing using a foaming agent [9], coating of polymer foams [10], or using melt infiltration techniques [11], the characteristic dimension of the porosity is usually in the range of 0.01-10mm. In this work, sintered metals and metal sponges are analyzed after the theory of sound absorption is briefly outlined. Then, measurements of the acoustic absorption of metal sponges and sintered metals in an impedance tube are performed. To understand and predict the acoustic properties of metals with open porosity, it is necessary to characterize the materials as precisely as possible. This is explained in detail using a line segmenting technique, followed by a discussion of the connection of pore characteristics and acoustic absorption. Finally, a conclusion is given."

Jan 1, 2012

By C. T. Morley

The steadily increasing interest in high pressure grinding rolls (HPGR) as a legitimate alternative comminution technology for hard rock applications has led to a proportional increase in the demand for trade-off studies comparing HPGR with more established approaches, typically SAG-based but including AG and stage-crushing designs. The primary trade-off is between a) the higher capital cost typically incurred with HPGR-based designs and b) the higher operating costs of the more traditional technologies. However, if, through circuit design innovation, the capital cost penalty of HPGR circuits could be eliminated or reversed, then the need for trade-off studies would diminish.

Jan 1, 2012

Slurry flow, including flow through the charge, through the discharge grates, along the pulp lifters and its discharge from the mill is an important contributor to the efficiency of the grinding process within a SAG mill. Poor transport of finer ground material can adversely affect grinding leading to excess energy consumption and over-grinding of fine material. This paper extends a 1-way coupled DEM-SPH method to three dimensions and applies it to a 1.8 m diameter by 0.6 m long AG/SAG pilot mill. This provides detailed information on the internal flow of slurry within a SAG mill, including the prediction of dry regions and of slurry pooling. Full 3D analysis also allows the pulp flow patterns into and out of the mill via pulp lifter chamber to be investigated.

Jan 1, 2012

By F. J. Hrach, S. A. Gasiorowski, J. 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. 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 (500 µm) materials with very high throughputs.. The technology has been also successfully applied to the beneficiation of a variety of minerals including calcium carbonates, talc, and potash. TECHNOLOGY OVERVIEWThe ST separator utilizes electrical charge differences between materials produced by surface contact or triboelectric charging. When two materials are in contact, material with a higher affinity for electrons gains electrons and thus charges negative, while material with lower electron affinity charges positive. This contact exchange of charge is universally observed for all materials, at times causing electrostatic nuisances that are a problem in some industries. Electron affinity is dependent on the chemical composition of the particle surface and will result in substantial differential charging of materials in a mixture of discrete particles of different composition.In the ST separator (Figures 1 and 2), material is fed into the thin gap 0.9 – 1.5 cm (0.35 -0.6 in.) between two parallel planar electrodes. The particles are triboelectrically charged by interparticle contact. For example, in the case of coal combustion fly ash, a mixture of carbon particles and mineral particles, the positively charged carbon and the negatively charged mineral are attracted to opposite electrodes. The particles are then swept up by a continuous moving open-mesh belt and conveyed in opposite directions. The belt moves the particles adjacent to each electrode toward opposite ends of the separator. The electric field need only move the particles a tiny fraction of a centimeter to move a particle from a left-moving to a right-moving stream. The counter current flow of the separating particles and continual triboelectric charging by carbon-mineral collisions provides for a multistage separation and results in excellent purity and recovery in a single-pass unit. The high belt speed also enables very high throughputs, up to 40 tonnes per hour on a single separator. By controlling various process parameters, such as belt speed, feed point, electrode gap and feed rate, the ST process produces low carbon fly ash at carbon contents of 2 % ± 0.5% from feed fly ashes ranging in carbon from 4% to over 30%."

Jan 1, 2012

By Nils Eivind Kamfjord, Halvard Tveit, Ingeborg Solheim

"Because of its negative environmental effect the attention towards NO emissions increases. This again leads to new demands from the authorities for better surveillance and control of emissions. Earlier and recent industrial measurements towards FeSi- and Si-metal furnaces reveal quite high NO-emission. The NO is believed to be produced in the combustion zone above the furnace surface, mainly as thermal NO.In order to expand the knowledge on NO-formation in silicon metal production, a pilot scale experiment in a 440 kVA silicon furnace has been carried out. The experimental set-up was designed with a view to be able to copy and manipulate the formation mechanisms for NO by controlling the flow of false air into the off-gas system.The resulting NO-values corresponding to the different air inlet to the furnace top, show significantly differences between the different air inlet geometries.IntroductionNOx is the common notion for the two gases nitric oxide (NO) and nitrogen dioxide (NO2). Since combustion of fuels, such as gasoline, diesel, bio diesel, propane, coal, and ethanol, forms NOx the dominating contributors to NOx emissions are the on-/offshore transportation industry and power generation based on fossil fuels [1]."

Jan 1, 2012

Advanced process and equipment analytics have been around for a while. However, with accessible IT infrastructure and site maturity, it is possible to analyse, monitor, and control processing plants and equipment easily. These various disparate systems provide different reports requiring the involvement of various personnel and attention to different reporting platforms. For efficient harnessing of the systems? capabilities, as well as effective improvement and monitoring of process and equipment, a single point of entry is required. A process and equipment optimization solution was required at a concentrator in South Africa, focussing on the product stream of platinum group metal (PGM) concentrate from the UG2 Reef. The investigation of data to identify strategies for optimization was required to allow visibility into plant operations to guide operators, an easier method to identify process loop problems, identification of imminent equipment failures, and advanced process control to optimize throughput and stability. A collaborative effort between the client and General Electric Intelligent Platforms (GEIP) investigated data-driven solutions to each of the problems. With the focus on process optimization and asset monitoring, as well as equipment monitoring, a combination of approaches was utilized to address the various problem areas that were identified. Each was implemented separately in the control layer of the plant IT infrastructure. The integration was done in a centralized web-based reporting tool that integrated the detailed results from the various solutions. On the process control side, monitoring of control loops was included by calculating performance statistics that were reported daily to identify sub-optimally performing control loops and indicating potential problems. The advanced process control solution for this site includes a surge tank controller, stabilizing flow through the flotation banks, and preventing the surge tank from overflowing or running empty. Equipment monitoring was investigated, for preventative maintenance, by making use of statistical data models to indicate imminent equipment failure. These predicted alarm events included the cause for failure, drilling down, and allowing focus on a specific variable for preventative action. The results included a more stable flow through the mill, with fewer stoppages due to surge tank overflows or running empty. The causes for process drift could be identified and operators could react early. Alarms warning of equipment failure 2½ and 4 months in advance were identified in an offline analysis.

Jan 1, 2012

By S. Özgen

In this study, the possibility of beneficiation of chromite tailings in the Uckopru/Fethiye-Turkey region by a combination of hydrocyclone and multigravity separator (MGS) was investigated. The two significant operational parameters of hydrocyclone, which were diameter of the apex and diameter of the vortex, and the three significant operational parameters of the MGS, which were drum speed, tilt angle, and wash water, were varied and the results were evaluated with the central composite rotatable design. In order to produce a chromite concentrate by hydrocyclone and MGS, mathematical model equations were derived by computer simulation programming, applying the least-squares method using Minitab 15. Second-order response functions were produced for the grade and recovery of chromite concentrates.

Jan 1, 2012

By M. Tanaka, H. Narita, K. Morisaku

"The selective separation of palladium (Pd), platinum (Pt), and rhodium (Rh) from a hydrochloric acid solution by solvent extraction was investigated using amide-type extractants, i.e., N,N,N’,N’-tetra-n-octyl-thiodiglycolamide (TDGA) and N-n-hexyl-bis(N-methyl-N-n-octyl-ethylamide) amine (BisAA). The separation experiments employed two separation schemes: (1) extraction of Pd with TDGA and that of Rh and Pt with BisAA; and (2) extraction of Rh, Pd, and Pt with BisAA. Separation scheme 1 achieved the highly selective separation of each metal. For separation scheme 2, Rh can be recovered prior to Pd and Pt, despite having a lower selectivity for Pd/Pt than separation scheme 1. INTRODUCTIONThe recent increase in the use of platinum group metals (PGMs) in industry (especially auto catalysts containing palladium (Pd), platinum (Pt), and rhodium (Rh)) has lead to their increasing waste; therefore, improvements in the recovery techniques for PGM have received significant attention. In metal refineries, PGMs are mainly separated and purified by solvent extraction (Cox, 2004). The extraction process used in INCO’s Acton precious metal refinery is one of the most famous commercial processes and is utilized worldwide. In this process, silver is first removed as a residue (AgCl), and then gold, Pd and Pt are extracted from hydrochloric acid (HCl) solutions using dibutylcarbitol (DBC), dialkylsulfide (DAS), and tri-n-butylphosphate (TBP), respectively. Finally, Rh remains in the raffinate (Barns & Edwards, 1982).The development of a successful solvent extraction process depends on the choice of the appropriate extractants. We have studied the extraction of PGM using N,N-disubstituted amide compounds (Narita, Tanaka, Morisaku, & Abe, 2004; Narita, Tanaka, Morisaku, & Tamura, 2006; Narita, Tanaka, & Morisaku, 2008a, 2008b). They are relatively stable against acids, and their metal extractability can be improved by changing the side chain length and/or introducing additional donor atoms like sulfur and nitrogen. We have recently found that thiodiglycolamide and an amide-containing tertiary amine have good extractabilities for Pd and Rh, respectively."

Jan 1, 2012

By Ting Lu, Gerard Laman

"This document compares the systems of coal classification described under ASTM standards used in Canada to GB standards used in China. A preliminary connection of metallurgical coal classes was set up between the two classifications. In GB classification system, there are nine metallurgical coal groups, namely PS, SM, JM, FM, ½ ZN, RN, 1/3 JM, and QM used in coal blending for coke production. PS coal is almost equivalent to the Low Volatile Bituminous coal; SM, JM, and FM coal groups fall into Low to Medium Volatile Bituminous range; ½ ZN, RN, 1/3 JM, and QM are equivalent to bituminous coal with medium to high volatile matters; QF contains higher volatile bituminous coal compared with High Volatile Bituminous coal. The caking properties commonly used in respective country are also compared in this document. These properties include free swelling index (FSI) and maximum fluidity used in Canada, as well as caking index (GR.I.), and the maximum plastic layer thickness (Y) mainly employed in China. It has been observed that the log of the maximum fluidity has a stronger correlation with the caking index than the Y values. Metallurgical coal processing strategy and typical coking coal product qualities are briefly discussed in the last section of this paper. Currently there is a trend to use heavy medium cyclone in both countries. In Canada the conventional two-product cyclone technology is the preferred practice; whereas in China the three-product heavy medium cyclone arrangement is widely used.INTRODUCTION Coal can be simply classified by applications into two categories: i) thermal coal used to provide heat energy in combustion, and ii) metallurgical coal which is converted to coke, in a carbonization process, and used mainly in the iron and steel industry. Metallurgical coal contains even higher heating values than thermal coal. In addition, it presents unique plastic properties during carbonization which in turn produces a porous solid, high in carbon referred to as coke. Coke is one of the most important raw materials in the iron and steel industry."

Jan 1, 2012

By Antonio Mendoza

El presente texto describe el sistema de manejo de agua y aire, las actividades integradoras, preventivas, de análisis y ejecución realizadas para describir la respuesta a los retos del futuro inmediato para alcanzar los objetivos ambientales en la mina Antamina.

Jan 1, 2012