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By A Smirnov

The problem of thin and very thin coal seam extraction is examined in a long perspective of Ukraine?s fuel and energy industry development. The technical and economic benefits of the coal seam selective mining technique are described, including beneficial environmental impact.

Aug 1, 2013

By D. J. Sapsford

This paper details results from laboratory simulation of an innovative underground bioleaching process. The underground reactors are periodic flushed with recycled leachate to remove uranium that accumulates within the reactor water. This leaching cycle has been recreated within the laboratory. This study examines the influence of varying cycle protocol on uranium leaching. Protocol variants examined include variation of flushing frequency, flush volume, leachate recycle, nutrient solution (NPK) addition to reactors and Fe(III) sulphate addition to reactors. The presented data highlight the dramatic improvements in uranium recovery that might be achievable by varying the operating protocol for the actual underground reactors.

Aug 1, 2010

By M. Timberlake, A. J. Jonaitis

"The DENVER Tube Press is a simple, high pressure (1500 PSI (100 bar)) filtration unit, developed for processing difficult-to-dewater materials and to produce a handleable filter cake and clear filtrate product.Lab and Pilot testwork conducted in Australia on coal fines (55-70% -35 micron (400 mesh)) have shown that total moisture contents of less than 20% are consistently achieved in the final cake products from the Tube Press.currently, these coal super fines are sent to waste due to uneconomical mechanical dewatering methods, which were only able to reduce total moisture levels in excess of 30%. Calculated, throughput rates for the 500 series Tube Press exceeded 1700 kg/hr (3750 lbs/hr). Feed solids concentration requirements are between 45 and 50% to achieve these results.INTRODUCTIONThe DENVER Tube Press is an automatic membrane high pressure filter press, which operates at hydraulic water pressures up to 1500 PSI (100 bar). The Tube Press was developed in the late 1960's by Charlestown Engineering, st. Austell, Cornwall, England, formerly a division of English China Clays, Ltd., to address more effective methods of moisture reduction of micron-size china clays. The Tube Press reduced moisture sufficiently to produce a hard surface-dry, handleable cake and clear filtrate discharge, which was recycled into the process. This development work was conducted using a 200 Series Tube Press (200 mm diameter x 2500 mm long filter surface)."

Jan 1, 1993

By A. F. Banks

"IntroductionThe typical potash processing plant recovers and/ or upgrades from 10% to 20% of its production through the recrystallization process. The feed to the recrystallization section consists of preconcentrated slurries of fine crystal size that cannot be raised to the required product grade by flotation and fine dusts also of low grade and too fine for compaction feed. It produces high grade white potash crystals that can be marketed as a high grade product or blended into the flotation products to raise their grade. In this chapter, a typical leaching (dissolving) and recrystallization operation will be discussed.The crystallization process makes use of the three phase system chemistry of NaCl, KCl, and H,O. The normal potash process operates on a temperature range of 75°F to 95 °F. A three phase slurry feed to the dissolving circuits will be within that range. The potash (KCl) is dissolved by heating the slurry in the presence of sufficient brine to a temperature of 190°F to 200°F. As the slurry is heated, the potash (KCI) dissolves and the salt (NaCI) precipitates. The potash rich brine is then clarified and the salt and other undissolved solids removed by thickening. Clarified brine becomes the crystallizer feed.The hot brine is cooled in evaporative cooling crystallizers. In cooling, the potash precipitates as a high grade white crystal. Crystallization is done in multiple effects to permit energy recovery and control of the process. In a four effect crystallizer the cooling is done by recycling mother liquor counter currently through the first two effect condensors and using brine pond brine for the cooling of the last two.The crystallizer product is removed from the last effect as a slurry at normal process temperature and is fed either to its own centrifuging and drying circuit or blended with the flotation product for centrifuging and drying."

Jan 1, 1989

Polymer electrolyte membrane (PEM) fuel cell has increasingly become the potential choice of zero-emission power source for portable, mobile and stationary co¬generation applications. However, technical barriers need to be overcome before its widespread commercialization; cost reduction and performance improvement including reliability are the two key areas, that can be realized through better cell/stack design and improved understanding of the transport processes occurring inside the individual cells and stacks. In this presentation, we will provide an overview of various cell/stack models that are available in the literature, their strength and weakness, and then present a comprehensive multi-species, multi-phase and multi-dimensional formulation of a single PEM fuel cell, with consistent and systematic formulation for all the regions involved, including the solid bipolar plates, gas flow channels, the electrode backing layers, the catalyst layers and the electrolyte membrane. Such a detailed approach allows us to extract sufficient information to the analysis of a stack of PEM fuel cells. Stack model will be presented that investigates the various stack designs and flow configurations, and the optimal stack design based on the present study will be described. Also some innovative cell/stack designs will be featured.

Jan 1, 2005

By Aimee Williamson

Bio-mining is a cost-effective, energy efficient and potentially environmentally protective method of exploiting a variety of ore deposits, from high-grade base metal deposits of nickel to lower-grade uranium deposits such as are found in the uraniferous quartz-pebble conglomerate beds of the Quirke Syncline, Elliot Lake, Ontario, using bacterial metabolic processes are used to enhance the solubilization of the metal(s) of interest. The cost effectiveness of bio-mining in Elliot Lake depends on the bacterially-influenced dissolution metals of economic importance, as well as on the ability to suppress microbiological activity following the release to solution of the economically important elements. This poster provides an overview of elemental recovery results and release kinetics for more than 50 elements. The data is obtained using a combination of advanced spectroscopic tools (ICPAES and ICP-MS) to analyze solutions obtained from a series of environmentally controlled biologically mediated uranium ore extraction experiments. The focus will be on rare earth elements, potential environmentally toxic elements, and metals of economic importance. Furthermore, the importance of these findings will be put into an economic and geologic context for the re-development of the mining industry of the Elliot Lake Camp.

Aug 1, 2010

By John S. Stevenson

"Although we have no uranium- producing mines as yet in British Columbia, uranium, associated with gold and cobalt, has been found in two deposits in amounts such that the combined value of the metals not only warrants the further exploration of these deposits, but also encourages the search elsewhere in the Province for other similar deposits.Where uranium-bearing veins have been found in British Columbia, the uranium mineral is the crystalline variety of uranium oxide, uraninite, rather than the massive, non-crystalline variety, pitchblende, such as found in the Great Bear Lake deposit and in other similar deposits along the southwestern margin of the Precambrian shield.The principal occurrences of uranium known so far in British Columbia are associated with bodies of granodiorite and quartz diorite along the eastern side of the Coast Range belt of batholiths. In this part of the Province, interesting amounts of uranium occur on the Gem property in the Bridge River area and on the Victoria property south of Hazelton; and smaller amounts occur on the Red Rose, Rocher Debouze, Delta, and Ohio properties, also south of Hazelton. At the Gem and the Victoria, the uranium mineral, identified as uraninite, occurs in deposits that also contain abundant cobalt-nickel sulpharsenides, and molybdenite.At these properties, the uraninite occurs as clusters of small black crystals of sub-metallic lustre that may be seen upon careful -searching of a highly radioactive specimen with a hand lens. Under the microscope, the uraninite is seen to be in the form of cubes or modifications of cubes that may occur as individual grains widely scattered throughout the gangue or may be gathered into clusters of several grains. The grain size of the uraninite is in general small. Although a few clusters of grains are up to about 10 mesh in diameter, the individual grains, whether in clusters or widely disseminated, are rarely more than 400 mesh in diameter."

Jan 1, 1950

By H. Saari, M. Pates, P. C. Patnaik, A. Merati

Single crystal nickel-base superalloys such as PWA1484 exhibit superior performance compared to conventional superalloys, and are used extensively in turbine blade applications requiring good high temperature properties. The life of these blades is typically limited by cracks and erosion. Due to the high cost of these blades, welding techniques are being considered to weld/repair worn components, extending their useful lives and delaying the need for expensive replacement components. However, the sensitivities for solidification cracking and post weld heat treatment cracking are relatively high in these alloys. Electron beam (EB) welding can deliver concentrated heat sources and has the potential to address these issues. Numerous welding trials and structural tests must be conducted to identify the optimum method and welding parameters. Weldability is studied over a range of material conditions, welding parameters, and directions. The influence of welding parameters on the fusion zone microstructure and resultant weldability is investigated using combination of microscopic examination and micro-hardness testing. This paper summarizes some of the results of a feasibility study conducted to understand the effects of welding parameters on localized microstructural features, cracking sensitivity, and mechanical properties of autogenously EB welded coupons of single crystal PWA1484.

Jan 1, 2004

By K. Yoo

Chalcopyrite is the most abundant copper sulfide mineral, which is normally processed using pyrometallurgical methods (i.e., smelting) to produce copper metal. Smelting has several major disadvantages, such as high gas-handling costs, high capital costs, saturation of sulfuric acid market, and inability to treat low-grade concentrates and to recover some by-products, such as zinc, nickel and cobalt. The development of hydrometallurgical processes for chalcopyrite is desirable to overcome the problems of smelting. Because chalcopyrite is refractory, the leaching rate for chalcopyrite is very low. Therefore, increasing the leaching rate has been extensively investigated, both in sulfate and chloride media, as well as in the presence of bacteria. Chloride leaching processes have shown relatively high leaching rates. The mechanism of the chloride leaching process has been investigated, but the behavior of chalcopyrite leaching in chloride solution is not clear. Therefore, the effect of the solution redox potential on the leaching rate of chalcopyrite in chloride solution was investigated. In the present study, leaching experiments were carried out using 0.1 M chloride solutions and the results indicate that high leaching rates of chalcopyrite can be achieved at relatively low solution redox potentials.

Jan 1, 2007

By Bryn Harris

Answer to the question is given as 42! Asked the wrong question So got the wrong answer How does this apply to the mining industry? And particularly to this session on Water? Water is just one aspect of mining/minerals/metals Should not be looked at in isolation Need to adopt a ?holistic? approach

May 1, 2013

By D. R. Griffiths

"Oxidation of pyrrhotite prcxiuces sulphuric acid which in turn leaches out heavy metals, resulting in acidic contaminated seepages. The establishment of a marsh on top of the pyrrhotite would result in an anaerobic sediment, which should prevent further oxidation of the pyrrhotite. Initial data indicates that concentrations of sulphates and heavy metals in the seepage water are greatly reduced. Further hydrogeological studies are required however, to determine if metal and acidic loadings to the environment have increased.L'oxidation du sulfure de fer produit de l'acide sulfurique qui a son tour attaque les métaux ayant pour resultat une contamination d'acide et de métal des eaux d'infiltration. L'etablissement d'une couverture faite de boue et de vase au-dessus du depot du sulfure de fer réduit les effets de l'oxidation.Les données initiales indiquent que les concentrations de souffre et de métaux dans les eaux d'infiltration sent grandernent réduites.Des études plus poussées sent nécessaires pour déterminer si les quantités de souffre et de métaux dans les eaux d'infiltration ont augmentées.INTRODUCITONPyrrhotite tailings are readily oxidized through a combination of precipitation and atmospheric oxygen causing acidification of the unsaturated zone above the water table. This reaction is usually catalyzed by the bacteria, Thiobacillus ferooxidans. As the pH decreases, heavy metals become more soluble resulting in contaminated seepages to ground and surface waters.By creating a marshland on top of the pyrrhotite, an anaerobic intermediate layer should form between the organic covering and the tailings, preventing the oxidation process from progressing.In September 1986, Falconbridge Limited implemented a tailing reclamation project that involved creating a marshland on top of pyrrhotite tailings. The following paper will discuss and illustrate the preliminary results obtained during the sampling period of May to September 1987."

Jan 1, 1988

By J. B. De Hart

In the September issue of the Bulletin, 1923, there is a paper by J. A. H. Church on "The Spontaneous Combustion of Coal in Mines", which is more or less a general discussion of the subject. Mr. Church gives a list of mine fires which have occurred in Alberta. Of the total of thirteen fires, six are attributed to spontaneous combustion. Of these six fires, it will be noted that five are in thick pitching seams. These fires occurred in the following mines during the years shown, at Frank in 1909; at Lovett in 1916; at Cadomin in 1920; at Yellowhead in 1922, and at Cadomin in 1923. Every one of these fires has occurred, as Mr. Church points out, in a seam of over 12 feet in thickness, and furthermore not one of these fires has been extinguished, although in every case large sums of money were expended and considerable risks . taken in fire fighting. Now it is quite evident from these facts that mines working seams of this nature are faced with a very grave danger and it behooves us to study the matter and endeavor to arrive at some practical method of preventing the loss of our coal mines from this cause.

Jan 1, 1924

By Paul Stothart

Context ? Industry is active in urban, rural, and remote regions ? Faces a range of environmental challenges and ?social license? issues ? There are also Aboriginal and northern issues ? Also very active internationally, with associated challenges ? Environmental/social groups often target the industry ? The important contribution of the industry should not be overlooked Useful Minerals and Metals Minerals are intrinsic to the residential, municipal, communications, and transportation infrastructure of modern life. Examples: Hybrid motors - nickel hydride batteries Water purification systems ? nickel, rare earth elements Catalytic converters - cerium Screens and monitors - several rare earth elements Clean electricity - uranium Circuitry - gold, copper, aluminium, lithium, titanium, silver, cobalt, zinc Instruments - copper, silver, nickel, cobalt, copper, brass Protective products ? zinc, calcium carbonate, sulphur

May 1, 2008

By B. Galy, L. Giraud

"This paper compares Canadian provincial mining safety regulations addressing hoist safety, automatic hoisting, and shaft obstruction. The regulations are quite similar among provinces, with only slight differences. Risk-mitigation strategies used in other industries are discussed, including their applicability to mine hoists. The specific case of software safety is introduced through examples. The mitigation of software failure is based on the use of the software lifecycle as recommended by the International Electrotechnical Commission (IEC) 61508 standard. Finally, ways to improve hoist safety are proposed.RÉSUMÉ Le présent article compare entre elles les diverses réglementations provinciales canadiennes concernant la sécurité des machines d'extraction, le levage automatisé et les obstructions dans les puits. Les réglementations sont assez semblables entre les provinces, mais elles comportent de légères différences. Les stratégies d’atténuation des risques utilisées dans d’autres industries sont abordées, incluant la possibilité de les appliquer aux treuils de mines. Le cas spécifique de sûreté des logiciels est abordé par des exemples. L’atténuation de la défaillance des logiciels est basée sur l’utilisation du cycle de vie du logiciel, comme cela est recommandé par la norme 61508 de la Commission électrotechnique internationale (CEI). Des moyens d’améliorer la sécurité des treuils sont également proposés."

Jan 1, 2016

By Arnaud Faucher, Amar Sabih, Sudarshan Martins, Tristan Martin, Sami Makni, Peter Radziszewski, Poorya Hosseini, Francois-Raymond Boyer

The measurement of acoustic signals produced by a tumbling mill has been previously used to determine the operating state of the mill and correlate the variations of the sound intensity with the operating conditions of the mill. Separately, the discrete element model (DEM), a software simulation of the mill, was developed to provide insight into the operation of the mill. Presently, there has not been much work reconciling the DEM simulation of the mill with the acoustic signal. Working from basic principles of linear, time-invariant systems, agreement between an acoustic DEM simulation and the measured signal is sought. First, the impulse response function of the mill is measured. The DEM provides the forces applied to the mill shell as a function of time. A convolution of these simulated shell forces and the transfer function gives the simulated acoustic signal. This signal is compared to the measured acoustic signal, both in the time domain and the frequency domain. Finally, a discussion of the results is given.

Jan 1, 2012

By Jorge Loredo, Jesús Garía Iglesias

"Abstract - The Asturian fluorspar district consists of vein and stratiform deposits where mineralization is controlled by a combination of lithological and tectonic factors.It is postulated that these fluorspar deposits have been formed under disequilibrium conditions created during circulation of ascending hydrothermal solutions along faults and other high permeability conduits. Mixing of solutions is inferred from fluid inclusion studies. Cavity filing and replacement processes are very important in localizing the ore deposits and in determining their morphology.Permian volcanic rocks in the area yield a regional positive geochemical anomaly in fluorine implying that Permian vulcanism may be a possible primary source of fluorine.On a regional scale a relationship can be established between some of the ore deposits and important tectonic lineaments. The stratiform deposits preferentially occur within a calcareous-detrital facies located at the margins of basins. These basin margins are related to important synsedimentaryfaults.Fluorite is the only economic mineral in these deposits. Quartz, carbonates, barite and pyrite are comnmon minerals accompanying fluorite. Other minerals that may occasionally be present as minor components are: marcasite, chalcopyrite, fahlore, sphalerite, galena and related supergene minerals."

Jan 1, 1994

By Robert B. Parsons

"The Canadian tax treatment of mining operations outside Canada is not as attractive as the treatment of Canadian operations. Further, the Canadian company that invests abroad a host of complex rules. This month, Tax Notes examines some of the major Canadian tax considerations confronting the Canadian company that wants to invest abroad. IntroductionCanadian-based mining companies are investing abroad more than ever before. These foreign investments trigger a complex set of tax rules that are distinct from the rules that apply to Canadian investments. In most cases, careful tax planning is mandatory if the company's tax liabilities are to be minimized. This article summarizes the main tax considerations that need to be taken into account with respect to a mining investment outside Canada.Branch Versus SubsidiaryOne of the first questions that arises in connection with a prospective foreign investment is ""Should we invest directly (that is, in a branch operation), or should we invest through a foreign subsidiary?"". In the case of a branch operation, the Canadian company owns and operates the business directly - that is, the foreign business assets are part of the Canadian legal entity. In the case of a foreign subsidiary, the foreign business operation is owned and managed by that subsidiary. The tax treatment of a branch and a subsidiary can be quite different."

Jan 1, 1994

By Malcolm Scoble

School Values ?? Each other; ?? Students, & helping them develop intellectually, personally & professionally; ?? Freedom to pursue educational & research opportunities; ?? Home-work-life balance; ?? The geographic-business community in which we operate ; ?? The pursuit of excellence; ?? Our contribution to society; ?? Creativity & innovation; ?? Teamwork & collaboration; ?? Career development, achievement & reward.

May 1, 2008

By J. R. Shore, F. G. M. Gillett, E. J. Zickar

"The addition of fines to rod mill feed has been employed at Inco Metals' Frood-Stobie Mill since 1973. The fines, which act as a ""lubricant"", causes an increase in the pulp fluidity and assists the flow of feed through the rod mill. Fines addition was one of the main factors which led to improved rod mill performance and the elimination of rod mill tangles.This paper outlines the testwork performed in evaluating the addition of fines, and summarizes the beneficial effects on rod mill grinding efficiency, throughput rates, power consumption and noise level. INTRODUCTIONFrood-Stobie Mill is situated within the Frood-Stobie mining complex, on the southern rim of the Sudbury Basin. The Mill commenced operations in November, 1967, and has since processed in excess of sixty-five million tons of ore. Minus 8-inch ore is delivered to the Mill's coarse ore bin by two surface conveyor belts from the Frood and Stobie Mines, while Little Stobie ore is transferred by underground conveyor and hoisted directly into the coarse ore bin a long with additional Stobie Mine ore."

Jan 1, 1981

By Yongteng Dong, John P. Quinn, Bradford Wesstrom, Guikuan Yue

With increasingly low-grade copper ores being mined, it is difficult to handle growing concentrations of As, Sb, Bi and/or Fe in the whole flowsheet, especially during copper electrorefining. To better elucidate the effects of those impurities on the quality of cathode deposit and/or current efficiency, a detailed speciation study of the electrolyte under industrial conditions is required to quantitatively describe their distribution in the solution, thereby facilitating their effective control and removal. In the present study, a thermodynamic model of complicated iron-arsenic-copper-sulfuric acid electrolyte under industrial conditions was developed. The main species of those elements involved in the electrolyte were first identified, and their thermodynamic data were collected and critically assessed. Those data were then used to estimate the activity coefficients of species, and to calculate the equilibrium constants from 25°C to 70°C. The developed model provides a mathematical tool that is capable of quantifying the concentrations of free ions and complexes in terms of temperature and solution composition. Finally, oxidation-reduction potential measurements were employed to validate the model. INTRODUCTION In copper electrorefining, impurities like arsenic, antimony, bismuth and/or iron can partially dissolve in the electrolyte and accumulate gradually, and eventually cause problems such as bad cathode deposit (co-deposition with copper or mechanical inclusion from the floating slime), lower current efficiency, etc., which eventually increases the operating costs. The presence of impurities may substantially reduce properties of copper products such as conductivity, corrosion resistance, mechanical properties, and leads to more energy consumption (Schlesinger et al., 2011; Jafari et al., 2017). To remove these impurities, various methods have already been proposed and applied in industrial copper production, such as solvent extraction, ion exchange, chemical precipitation, absorption by activated carbon, etc. (Cunningham et al., 1997; Navarro et al., 1999; Toyabe et al., 1987). In addition, adding reducing agents such as sulfur dioxide and trivalent arsenic could also precipitate arsenic, antimony and bismuth from copper electrolyte, by changing the distribution of impurities with various valence (Braun et al., 1976; Xiao et al., 2007). The disadvantages of those methods include high energy consumption, serious contamination, lower selectivity and efficiency, and so on.

Jan 1, 2019