Internal structure of coal seams and mechanical stability

Abstract The syngenetic and epigenetic mechanics of sedimentation and deformation of coal seams resulted in various types of internal structure, as listed below:TYPE I—massive structure with evenly distributed coal constituencies of integrated mechanical properties. TYPE II—broad-banded structure, with bright and dull coal bands of differential mechanical properties. TYPE III—heterogeneous structure, with sheared coal bands and partings of sectional mechanical properties. TYPE IV—contortional structure, with refolded coal layers and deteriorated mechanical properties. TYPE V—porous structure of orogenically crushed and pulverized coal, with disintegrated mechanical properties.The study suggests criteria for the estimation of coal seam internal structure (gamma-gamma density log and cracks density log), which might be related to the evaluation of strata stability and coal mineability.
Keywords: Coal structure, Coal seams, Mechanical stability, Rock mechanics, Sedimentation, Deformation, Density logs, Fractures, Pillar deformation, Strata control.
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Publication: CIM Bulletin
Author(s): S.V. BURR
Issue: 841
Volume: 75
Year: 1982
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Summary: This paper provides a detailed account of longwall face mining at the National Coal Board's Thoresby Colliery in England. It illustrates the actual operations and procedures for installing equipment in a successful longwall operation.
Publication: CIM Bulletin
Author(s): T.E. WHEATLEY
Keywords: Coal mining, Parkgate seam, Longwall mining, Face mining, National Coal Board, Thoresby Colliery, Powered supports, Conveyors, Roof support.
Issue: 841
Volume: 75
Year: 1982
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Summary: The purpose of this paper is to determine the best techno-economic alternative for the treatment of tin ores, when comparing the various mining and metallurgical methods of pre-concentration, concentration, volatilization (fuming) and up to the final stage of selling to the smelter. The study of the influence of the different parameters of cost, recovery and quoted prices has motivated the paper, which aims at determining the best process of ore treatment in terms of its techno-economic...
Publication: CIM Bulletin
Author(s): JORGE LEMA RATING
Keywords: Metallurgy, Tin ores, Gravity separation, Flotation, Concentration, Smelting, Fuming, Non-ferrous metallurgy.
Issue: 841
Volume: 75
Year: 1982
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Summary: The need for grinding mills of ever increasing capacity and greater feed openings has tended toward mill trunnion diameters being beyond the size limits for roller bearings.Hydrodynamic plain bearings need to be wide enough to achieve the necessary bearing pressure in order to obtain an oil film with sufficient carrying capacity at low rotational speeds. This greater width increases edge loading resulting from the deflection of the mill under load.Because of the high surface pressure...
Publication: CIM Bulletin
Author(s): BO TRYGG, BRIAN MclNTYRE
Keywords: Bearings, Hydrostatic bearings, Shoe bearings, Mills, Trunnions, Grinding mills, Girth rings, Lubrication, Safety devices.
Issue: 841
Volume: 75
Year: 1982
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Summary: Full-scale sections of three different types of Grade 483 line pipe have been evaluated extensively. The variations in chemical composition, optical microstructure, tensile properties, hardness and Charpy impact toughness with specimen orientation and location were determined. Significant variations in several properties, notably Charpy shelf energy, impact transition temperature, inclusion content andferrite grain size, were observed for different locations in the pipes. The results indicate...
Publication: CIM Bulletin
Author(s): D.R. BELL
Keywords: Physical metallurgy, Line pipe, Steel, Pipeline steels, Microstructure, Tensile properties, Hardness, Charpy impact toughness, Foothills Pipelines Ltd., Alaska Highway Pipeline
Issue: 841
Volume: 75
Year: 1982
Text
Summary: Laboratory-scale sulphuric acid leach tests were conducted on Elliot Lake and Rabbit Lake ores in the presence of various oxidants, namely: Fe2(SO4)3, Cl2, H2O2, NaClO3, MnO2, H2SO5, HNO3, Oxone, K2Cr2O7, KMnO4, O3 and O2. Uranium extraction is significantly accelerated when an oxidant is present in the leach slurry. Uranium extraction of 96-99% can be achieved by maintaining the oxidation potential of the leach slurry in the range of 400 to 500 mV (S.H.E.). A rough cost comparison of all the...
Publication: CIM Bulletin
Author(s): K.E. HAQUE, G.M. RITCEY
Keywords: Hydrometallurgy, Oxidants, Leaching, Uranium ores, Sulphuric acid, Elliot Lake, Rabbit Lake, Acid leaching.
Issue: 841
Volume: 75
Year: 1982
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Summary: Extensive deposits of tectonically sheared coal of the Mist Mountain Formation occur in the southeastern Canadian Cordillera. The quality of the coal varies markedly; it is commonly partially oxidized even far from the present weathering horizon and locally has a disproportionately large amount of ash and poor washability characteristics.Oxidation of the sheared coal has been promoted by its fine grain-size and by fractures in adjacent rocks which have facilitated penetration of atmospheric...
Publication: CIM Bulletin
Author(s): P.M. BUSTIN
Keywords: Coal structure, Shearing, Cordillera, Mist Mountain Formation, Comminution, Eagle Mountain, Tent Mountain, Washability, Coal petrography, Vitrinite reflectance.
Issue: 841
Volume: 75
Year: 1982
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Summary: The Fond-du-Lac uranium deposit is located on the northern rim of the Athabasca Basin. The uranium mineralization is, for the most part, confined to the Athabasca Group, which is underlain by pre-Helikian metamorphic rocks of the Western Craton.The deposit is characterized by a remarkable train of mineralized glacial erratics which led to the original discovery. The mineralization is present as a "high-grade" core and a diffuse "low-grade" aureole. The "high-grade&quo...
Publication: CIM Bulletin
Author(s): LA. HOMENIUK, R.J. McH. CLARK, R. BONNAR
Keywords: Geology, Uranium deposits, Fond-du-Lac deposit, Athabasca Basin, Boulder trains, Pitchblende, Alteration, Ore genesis, Exploration, Mineralogy.
Issue: 841
Volume: 75
Year: 1982
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Summary: The orebodies of the Campbell and Dickenson mines are localized within an anomalously fissile and deformed zone that transects the eastern margin of a dominantly mafic volcanic complex, close to its contact with a synchronously formed sedimentary basin containing clastic and chemical sedimentary rocks. The ore zones are mainly quartz-carbonate fissure veins and siliceous replacement zones formed during deformation and metamorphism, although there are some syn-volcanic ex-halative ore zones in...
Publication: CIM Bulletin
Author(s): RJ. MacGEEHAN, T. SANDERS, C. JAY HODGSON
Keywords: Mineral exploration, Mine geology, Alteration, Wall-rock alteration, Campbell Red Lake mine, Dickenson mine, Red Lake district, Gold mines, Hydrothermal alteration, Spilitic alteration, Feldspar-destructive alteration, Lithogeochemistry, Geochemical anomalies, Peraluminosity index.
Issue: 841
Volume: 75
Year: 1982
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