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By Wm. D. Jr. Sheldon

THIS paper presents practical data to aid in the selection of a mine ventilating fan, and outlines considerations to be made to ensure satisfactory operation and optimum efficiency of the fan. Much has been published on the general subject of mine ventilation, but the writer has found few specific data on factors and considerations which govern the selection of a fan-data which should be available to the operator if his fan is to give satisfactory service within the range of the high-efficiency portion of its performance curve and deliver the specified air capacity when operating against the anticipated range of resistance of the mine. The total quantity of fresh air furnished by the ventilation system must be adequate to provide, and to ensure at all times, safe and healthful working conditions in the mine. It is assumed that the mine operator is able to determine the air quantities required for the various parts of the mine.

Jan 1, 1941

By T. Plikas, T. Porretta, M. Al-Dojayli, B. Pretorius, J. Woloshyn, H. Ghorbani

"Water-cooled ducts represent an integral part of high temperature off-gas systems in metallurgical processes. Typically, off-gas enters these ducts at significantly elevated temperatures; therefore, water cooling may be required to maintain the duct skin temperature within allowable design limits. These off-gases are typically of high mineral content that could lead to dust buildup, and there is a possibility of slag buildup / molten metal splashing. Therefore, dust cleaning provisions may be necessary in order to remove or minimize accretion on the duct wall, which could otherwise impact the water cooling and the system process efficiency. These ducts may have complex geometry and experience a wide range of loading, including gravity loads, water and gas pressures, cyclic thermal loading and dynamic impact forces. Consequently, the thermo-mechanical assessment of such water-cooled ducts is critical and requires consideration phenomena such as high temperature gradients, potential nucleate boiling, thermal ratcheting and fatigue failures. Such assessment is not comprehensively covered by design-by-rule design codes and guidelines due to its complexity. This paper presents a successful implementation example of design-by-analysis methodology to improve the design and extend the life of a water-cooled furnace transition duct using Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA).INTRODUCTION Water-cooling represents an important part of high temperature off-gas systems in metallurgical processes. Typical temperatures of the off-gas in the furnace uptake are in excess of 1400°C, and thus there is a need to maintain the water-cooled duct and jacket skin temperatures within their material allowable design limits. Water-cooled channels have been used effectively in arc furnace roof design (Sosonkin et al., 1972; Smolyarenko and Khainson, 1988) and other furnaces as well as in furnace fuming jackets (Scholey et al., 1994). The design of these systems was based on one-dimensional analysis to ensure sufficient cooling is available under extreme furnace conditions (Smolyarenko and Khainson, 1988; Scholey et al., 1994). With advancement in furnace and fuming system designs, water-cooled duct designs have become more complicated in geometry. Numerical techniques, such as three-dimensional fluid flow and heat transfer modeling, are therefore needed to more accurately calculate water velocity, temperature and convective heat transfer coefficients in the water-cooled channels (Haywood et al., 2002; Henning et al., 2010). This is of particular importance around geometric corners where stagnant water flow may lead to local nucleate boiling at the critical heat flux, causing hot spots (Bergman et al., 2011). High wall skin temperatures increase the risk of failures due to thermal stresses as well as increasing corrosion rates (Gelfi et al., 2012), leading to costly equipment downtime and potential safety risks."

Jan 1, 2017

By M. J. Nicol, T. Moyo

Ammoniacal solutions are an effective lixiviant for the oxidative dissolution of some mineral sulphides. A detailed study of the anodic dissolution of chalcopyrite in ammonium sulphate-ammonium hydroxide solutions has been carried out using cyclic voltammetry, chrono-amperometry and rest potential measurements. The role of the copper(II)/copper(I) redox couple in the oxidation process has been evaluated. Rest potentials have been found not to be affected by oxygen but to increase with an increase in initial copper(II) concentration. Pseudo-steady-state anodic current densities measured in the absence of copper(II) ions at the rest potentials obtained in the presence of copper(II) ions increase with increasing concentration of copper(II) ions, confirming the positive effect of copper(II) ions on the rate of dissolution of the mineral. Cyclic voltametric and chrono-amperometric data show that in the absence of initial copper(II) ions, the rate of dissolution in the presence of dissolved oxygen is significantly lower. These results confirm that the effective oxidant for the mineral under the conditions of the study is copper(II) and not dissolved oxygen. Coulometric measurements have been used to establish the stoichiometry of the anodic reaction at different potentials.

Jan 1, 2014

By Peter C. Jones, Wanda M. Carter, David H. Watkinson

"Abstract - Pyrrhotite, chalcopyrite, and pentlandite are the dominant sulfide minerals in the 740 zone of the Kelly Lake orebody (Inco Ltd.), Copper Cliff Offset, Sudbury. Petrographic and quantitative electron microprobe analyses of minerals, from sulfide assemblages and host quartz diorite, of the 740 deposit have revealed three processes that have affected sulfide mineralization and associated sulfarsenide and platinum-group-mineral (PGM) distribution: magmatic, hydrothermal, and tectonic. Accessory, zoned cobaltite, and gersdorffite occur in sulfides as a result of these three processes, and PGM occur dominantly in hydrothermally remobilized and deformed ores. Where PGM are present in sulfarsenides they provided nuclei for sulfarsenide growth. Solitary PGM are orders of magnitude larger than those PGM found within sulfarsenide minerals. Five varieties of PGM occur, michenerite and sperrylite being the most common, with lesser froodite, hollingworthite, and ruarsite.The effect of a deformation is a localized fabric in the ore, revealed by pyrrhotite and chalcopyrite bands; pentlandite porphyroblasts also partially define the foliation. The deformed ore is also characterized by alteration of the adjacent quartz diorite, which produced an alteration assemblage including almandine garnet, Fe-rich biotite, and chlorite."

Jan 1, 2001

By Greg Gosson, Larry B. Smith

"These are heady times for the mining industry, with strong metal prices, investor enthusiasm for the junior explorer and ready access to finance for mineral projects. Many projects were shelved in the past because of technical deficiencies — insufficient tonnes or grade, metallurgical problems, the deposit was too deep or too narrow, or the project was physically or economically under water. With the possibility of sustained metal prices, now is the time for those previously “challenged” projects to be re-evaluated and financing sought for continued development. The question is, do these deposits have reasonable prospects for economic extraction, as required by all mineral resource reporting codes? NI 43-101 defines a mineral resource as that portion of the mineral inventory that has reasonable prospects for economic extraction. However, a mineral resource is not simply an inventory of all blocks above a given cut-off grade. The spatial distribution and geological and grade continuity must also be considered. The qualified person (QP) must consider factors significant to project economics at the mineral resource estimation stage, and not just when qualifying mineral reserves. CIM Best Practice Guidelines for estimating mineral resources require the factors significant to project economics be current, reasonably developed and based on generally accepted industry practice and experience. In establishing the cut-off grade, it must realistically reflect the location, deposit scale, continuity, assumed mining method, metallurgical processes, costs and reasonable long-term metal prices appropriate for the deposit. Variations within the resource model (rock characteristics, metallurgy, mining methods, etc.) may necessitate more than one cut-off grade or economic limit in different parts of the deposit model. There must be sufficient knowledge of the metallurgical characteristics of the deposit, which should be supported by preliminary metallurgical test results."

Jan 1, 2003

By I. Lackey

In 2004, Zinifex Budel Zink commenced testing with the objective to increase the precipitation of aluminium in the iron purification stage of its hydrometallurgical zinc circuit, without the use of expensive reagents. Findings from the literature applied to the leach circuit at Zinifex Budel Zink demonstrated that aluminium removal from the leach circuit could be increased by lowering the ferric concentration and acidity in the vessels where jarosite precipitation occurs. An associated increase in copper precipitation was mitigated by limiting the extent to which the ferric concentration was lowered in the vessels where jarosite forms and lowering the ratio of copper to aluminium in the solutions entering these vessels.

Jan 1, 2006

By Georges Houlachi, Raynald Labrecque, Jean-Noël Cloutier

"Electrodialysis (ED) is an electro-membrane technology based on electrochemical process using electrical energy for the production of chemicals. The process can be used for concentrating, extracting, separating products, modifying molecules, purifying solutions, pH adjustment and regenerating salts into their base and acid. This paper reviews the principle of ED, present some of the different options and discuss applications that are relevant to the hydrometallurgy and mining industries for the treatment of effluents focusing on recovery of chemicals (acid and metals) and recycling of water minimizing the environmental footprint.INTRODUCTIONElectrodialysis (ED) is usually defined as an electrochemical separation process in which electrically charged membranes and an electrical potential difference are used to separate ionic species from an aqueous solution and other uncharged components [1]. ED technology consists of an electro-membrane technology based on an electrochemical process using electrical energy for the production of chemicals. It is a method combining electrolysis and dialysis was proposed for the first time in 1890 by Maigrot and Sabates [2]. In the late 1930s Teorell, Meyer and Sievers discussed membrane phenomena, revealed membrane potential, electric conductivity, transport number [3]. Meyers and Strauss introduced a multi-compartment ED apparatus consisting of two electrodes and a stack of ion-exchange membranes between them [1]. They succeeded to double the concentration of a KCL solution [3- Tarleton]. In general, ED consumes less energy than electrolysis to perform salt splitting. In that regard, one can expect an energy reduction of about 30% [4–5]. ED offers a great versatility in the domain of separation processes. Indeed, it can be used for concentrating, extracting, separating products, purifying by desalination, pH adjustment and regenerating a salt to acid and base components. This paper reviews the principle of ED, presents various options available and discusses potential applications relevant to the mining and metallurgy industries with economics of some successful industrial applications."

Jan 1, 2016

By M. Mirnezami, J. A. Finch, S. Uddin

A fast, reliable and practical way of measuring zeta potential using sedimentation potential method is proposed. A cell was designed along with the instrument control software to determine the required variables simultaneously i.e. sedimentation potential, specific conductivity, volume fraction of solid as well as pH. High purity alumina and silica powders were used as test samples. Measured zeta potential using the proposed technique was comparable with the results by electrophoresis.

Jan 1, 2009

By A. Hekmat-Ardakan

Conventional hypereutectic Al-Si alloys such as A390 are used principally for the casting of components used in wear applications requiring abrasive resistance such as in engine or compressor blocks. A comprehensive study was undertaken to investigate the potential of improving the mechanical properties of these alloys by the addition of magnesium. A thorough thermodynamic study of the effect of the addition of Mg to the conventional A390 alloy showed that Mg2Si starts to form as a primary phase at 4.2% Mg as well as in the products of the binary and ternary eutectic reactions forming the matrix. Experiments were carried out in producing castings with different cooling and solidification rates of alloys with up to 10% Mg. Mg additions were found to increase the hardness over the as cast alloy due to solid solution strengthening. Also, T6 heat treatment greatly improved the tensile properties of these alloy compositions due to the strengthening effect of the theta-Al2Cu phase. The elongation of these alloys generally decreases marginally with Mg content. The most significant property improvement of the alloys with higher Mg content is the substantial increase in wear resistance. This is attributed to the dispersion of smaller particles of Mg2Si and their coherence with the matrix as compared to the large Si particles in the conventional alloy. A new rheoforming process for A390 is presented that improves the processing of the semi-solid slurry. Structure modification elements were also added to refine the primary and eutectic silicon greatly improving the processing of the semi-solid slurry.

Jan 1, 2011

By L Munholand, G. Soucy, P. Quintal

This work presents early results from the first study to optimize the hydrodynamics of a Plasma Lift Reactor (PLR). The PLR is designed to break down organic contaminants in aqueous solutions. New experimental results are presented for air/water tests and for plasma degradation of organic contaminants in Bayer liquor. In addition, a multiphase Computational Fluid Dynamics (CFD) model has been developed which predicts the hydrodynamic behavior in the PLR. These results of this work suggest the PLR is effective at reducing contaminants in the Bayer liquor and that the CFD model adequately describes the hydrodynamic flow.

Jan 1, 2005

By R. I. Kraydenko, A. N. Dyachenko

"The possibility of SiO2 5N production by staged purification of ammonium hexafluosilicate (NH4)2SiF6 is discussed. High-purity silicon dioxide can be obtained with fluoridation of quartz concentrate by solid NH4F at 100 °C, with further sublimation of the product at 320 °C, its dissolution, ammonia hydrolysis, filtration and drying of SiO2•nH2O. This is accompanied by regeneration of the processing reagent - NH4F.INTRODUCTIONProduction of high-purity silica-5N (SiO2 content over 99.999%) is an important and urgent task of the modern chemical industry. This material is used in the manufacture of optical glass, optical fibers for internet cables, silicon for solar power and electronics.Quartz concentrate is raw material for the production of silicon dioxide. The existing technologies of synthetic silicon dioxide were introduced in the mid-twentieth century. These methods are energy-consuming, multi-step and do not meet stringent environmental requirements. In fact, as some conventional technologies became obsolete; it became necessary to develop new methods for the production of synthetic silica. We believe that the fluoride technology of processing of quartz materials by ammonium fluoride is the most promising direction.In industry, silicon dioxide marked ""Silica White"" is obtained by liquid-phase method. The method consists of the precipitation of amorphous silica from sodium silicate solutions with acids. The resulting product is filtered, washed and dried. Depending on the deposition conditions and nature of the coagulant the ""Silica White"" is acidic, neutral or alkaline. The dry product is subjected to grinding. The degree of dispersion and porosity of the particles of Silica White depends on the nature of decomposition agent (a substance that decomposes the silicate) and coagulant, conditions of sedimentation, filtration and drying. During the drying process the silica particles are sintered into aggregates of a few millimeters."

Jan 1, 2012

"Successive seismic waves may cause progressive weakening of a fault zone, which has been recognized as the mechanism of earthquake aftershocks. However, it is unclear that how a fault zone slips under each wave cycle and how slip displacement accumulates under continuous wave cycles. This laboratory study provides direct evidences on the slip process of a simulated granular fault zone dynamically induced by an incident wave without the effects of late-arriving and reflected waves. The experimental observations show forward and backward slip paths of the fault zone and partially recovered slip displacement after a wave incidence. The unrecovered slip displacement after each wave cycle can be accumulated until it reaches a critical slip distance for seismic faulting, which may reinterpret delayed triggering in earthquake dynamics. The limited interseismic period restricts fault self-healing in strength. The experimental results also indicate that the dynamically induced frictional slip on the fault zone is associated with a complex frictional system, including seismic wave radiation, frictional slip initiation and normal stress vibration. Different from the dynamically induced frictional slip on the fault zone, the statically induced frictional slip causes a permanent increase of slip displacement along the shear loading direction. INTRODUCTIONAn earthquake mainshock may induce aftershocks by suddenly changing external stresses applied to another fault zone in the near field (Kilb et al., 2000) and by slightly perturbing a fault zone from a critical steady state to stick-slip faulting in the far field (Gomberg and Davis, 1996). The dynamically induced frictional slip on a fault zone has been recognized as the mechanism of earthquake aftershocks (Marsan and Lengliné, 2008; van der Elst and Brodsky, 2010). Although earthquake aftershocks have been extensively studied by many seismological methods, a simplified laboratory fault zone can provide possible interpretation on real faulting and detailed analysis on a friction process (Dieterich, 1979; Nielsen at al., 2010). According to a few laboratory experiments related to the dynamically induced frictional slip on a simulated fault zone (e.g., Uenishi et al., 1999; Johnson et al., 2012), the slip process induced by successive seismic waves exhibits continuous motions. However, it is unclear that fault slip response under each wave cycle and slip displacement accumulation under continuous wave cycles."

Jan 1, 2015

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 M. S. Millman

Close monitoring of performance at each process stage, from raw material through to finished product, is vital for operational consistency and the production of high quality steel. However, many of the integrated iron and steelmaking process route stages operate under such severe conditions of temperature, dust, water, thermal radiation, vibration, pressure, vacuum, extreme dynamic events, high material flows, corrosion, erosion, electrical-noise, electromagnetic-noise, or audio-noise that, in general, it is a very difficult challenge to obtain useful information for control. Thus, state-of-the-art non-contact and remote sensors are applied to help monitor and control specific process operations. Often, these sensor systems have been developed especially for the steel industry and they are based on four principal technologies: Laser, Microwave, Electro-Magnetics and Thermal Imaging with supporting technologies such as: X-ray Fluorescence, Audiometry, Digital Image Processing, Radio Telemetry, GPS and many others. These advanced sensor technologies are reviewed with respect to their application at various stages along the integrated process route.

Jan 1, 2004

By Kurt Tischler

This paper presents the field experience of Siemens with regard to Gearless Drives in the mining industry ? We consider the elapsed production hours of Siemens Gearless Drives to be extensive enough to provide a reliable estimation of availability calculated on the basis of data representing repair time, downtime, and operating time. The users of Siemens Gearless Drives confirm an availability of more than 98% after exclusion of some major issues. The paper addresses all of these major issues of Siemens Gearless Drives, describes successfully applied corrective measures, explains the influences on the design of the drives, and lists the downtimes associated with each of these issues.

Jan 1, 2012

By Ma Yuxin, Niu Fusheng, Yuan Zhitao, Bai Limei, Han Yuexin

"Using batch flotation experiment, contact angle measurement, particle size analysis, and scanning electron microscope (SEM), the influence and difference of pH value on the flotation rate of talc and chalcopyrite were investigate without collector at the pH range of 3~11. The results showed that, the flotation rate of talc decrease with the increasing of flotation time, while that of chalcopyrite hardly affect by flotation time, besides, the flotation rate of chalcopyrite is much less than that of talc, so the laws of flotation rate of the two minerals are independent of pH value. The flotation test data of two minerals are simulated with first order and multi-rate flotation kinetic model respectively. The simulation results showed that flotation of talc only meet the first order kinetic model, while chalcopyrite’s meet the both. In addition, According to test results of talc and chalcopyrite by the particle size distribution, SEM photographs and the contact angle measurement, the reason why talc did not conform to the first order kinetic model is not because of particle size distribution, but of particle shape. That is to say, because of sheet structure of talc, the contact angle of layers and sections are 74°and 52°respectively. At the same time, the contact angle of layers and sections are different between the particles. So flotation rates between talc particles are difference.INTRODUCTIONPossessing superior self-induced, collector-induced and sulfur-induced floatability, chalcopyrite exhibits good floatability at a wide range of pH values and potentials. Serpentine are regarded as the most difficult selected type in various chalcopyrite ore, and the predominant reason is that it contains talc. Talc, as a nonpolar layered silicate mineral, is one kind of common associated mineral in sulfide ores (Lu, 2010). Concentrate quality and flotation process of chalcopyrite are influenced as a result from the presence of talc. It is because that talc has inherent floatability which makes it readily mixed with the floated mineral and talc is easy to slime causing the slime coating of the valuable mineral (Beattie et al., 2006). Thus in order to improve the flotation effect of chalcopyrite, methods can be introduced from two respects. One method is that fast-floating talc mineral is floated preferentially, and the other is that sulfide mineral is floated prior to talc by depressing the flotation of talc mineral (Beattie et al., 2006), nevertheless, no matter with which the flotation effect of fine-sized chalcopyrite is not positive. Therefore, in order to realize the flotation separation of talc and chalcopyrite, the difference between the inherent floatability of fine-sized chalcopyrite and talc is researched and analyzed in terms of flotation dynamics in the absence of collector and frother."

Jan 1, 2016

By J. Duby

"A description is given of a series of tests performed to determine the comparative effects which dynamic and static straining, in compression, have on the physical strength properties of mild steel and an aluminum alloy. The dynamic deformation was imposed during the passage of single stress pulses of about 100 micro-second duration. These pulses were recorded with strain gauges mounted near both ends of the specimen. The resulting records were analysed using a simple wave theory; there from the dynamic stress-strain curves for the respective metals were deter-mined and were then compared with the static stress-strain relation. The respective hardnesses of the metals after deformation are evaluates by means of static stress-strain curves in compression. The micro-structures of the metals before and after deformation are also shown. It is observed that dynamic de-formation considerably modifies the rate of strain hardening. This modified hardening appears to be persistent. The observed differences in physical strength properties and micro-structures are discussed in the light of the accepted dislocation theory for metals."

Jan 1, 1960

By E. Gaucher, D. C. Gagnon

"The paper refers to methods and concepts used in the computer treatment of banks of geophysical, geochemical and geological data, relating to the exploration of massive sulphides. In particular, a data bank of 400 drill holes on independent conductors can be used to calculate probability levels of intersecting a certain quantity of sulphides according to the characteristics of the conductor. Inversely one can, using the data bank and some cost assumptions, simulate and optimize the cost of intersecting a certain quantity of sulphides by selecting drill targets among conductors according to conductivity, magnetism or gravity. Problems of noise, inherent in any simulation, are illustrated in this paper by the results of a study of the nomenclature of volcanic rocks of 27 drill holes by forty geologists. Compilations of data banks are long and timeconsuming, and it would help to standardize to allow exchange of data. We believe that such efforts may result in the discovery of more mineral deposits and at a lower cost. The present study is supported jointly by SOQUEM The New Jersey Zinc Co. and Cominco Ltd."

Jan 1, 1973

By R. Lodha, C. Oprea, G. Oprea, H. Zargar, T. Troczynski

"The basic refractories used in non-ferrous industry contain chrome ore for improving the thermal shock resistance, thus reducing the penetration of molten metal and fayalite-type slags into the lining. The current study aims to replace chrome ore with Me4+ ions along with Fe3+ ions in order to form MgO-Al2O3- FeOx-Me4+O2 based complex spinel systems that could perform similar to the complex chromia-bearing spinel in the magnesia-chrome refractories. This system allows for lower temperatures of synthesis and sintering. In our study, compositions with 60% MgO were fired below 1500°C and resulted in complete formation of complex spinel, and open porosity less than 5%. The in-situ formation of the complex spinel from the fine mix of oxides in the MgO-Al2O3-FeOx-Me4+O2 system offers a suitable alternative of binding system to produce basic refractories at lower temperatures and of similar physical and mechanical properties with magnesia-chrome bricks fired above 1750ºC. INTRODUCTIONThe synthesis of magnesium aluminate spinel (MgAl2O4) (Maschio, Fabbri, & Fiori, 1988) or magnesium chromate spinel (MgCr2O4) from their respective oxides is diffusion controlled resulting in a sluggish reaction even at high temperatures. For instance, the diffusion of Mg2+ and Al3+ ions in the intermediate spinel layer during reaction is slower than the diffusion of Mg2+ in corundum and Al3+ in periclase. The interfacial layer of spinel formed during the reaction increases the diffusion path for the spinel forming cations. This accompanied by ~8% volume expansion retards further reaction resulting in incomplete spinel forming reaction during sintering and hence densification during the reaction cannot be achieved. In order to assess sintering studies with fine particulate oxides that would result in a lower diffusion path, a mechanical mixture of the hydroxides of aluminium and magnesium calcined at 1400ºC to 1600ºC for 1 hour does not result in complete spinel formation (Sarkar, Das, & Banerjee, 2003), which indicates that reaction sintering of stoichiometric magnesium aluminate spinel is retarded by initial reaction forming the interfacial spinel layer. The basic bricks used as linings in non-ferrous pyro-metallurgical convertors are manufactured using magnesia and chrome ore, the sintering of which produce spinel solid solution. This solid solution is a mix of both normal and inverse spinel structures that sinters at temperatures in excess of 1800ºC in air."

Jan 1, 2012

By T. G. Joseph, E. Lampard

ABSTRACT: Surface mining operations must manage variability from within their operations as well as variability imposed upon them by external forces. A framework to manage both internal and external variability through the continuous review and adjustment of a mine plan during active mining lifetime operation is introduced, to minimize lost production and maintain operational safety. The observational approach of “observe, evaluate, interpret, predict, and adapt” is employed as the backbone of this approach. Although written with a surface mining operation in mind, the framework outlined in this paper would be equally applicable to any mining or processing operation.

Jan 1, 2011