Rank variation, coalification pattern and coal quality in the Crowsnest coalfield, British Columbia

Abstract A rank-map of Crowsnest coalfield, showing the distribution of the bituminous coal measures and the locations of major structures, has been produced from vitrinite reflectance measurements on over 600 coal samples. The timing of coalification in relation to these major structures has also been determined.
In the west-central portion of the coalfield a complete stratigraphic succession of coal measures which rides on major thrust surfaces is all of high-volatile bituminous rank, but despite the structural discordance no break in rank is discernible across these structures. The thrust faults therefore predate much of the coalification.
Three major valleys expose cross sections of the folded coal measures and in each an increase in vitrinite reflectance is demonstrable as individual seams are traced from ridge crest to valley floor. Thus, in these sections, a significant amount of coalification post-dates folding. The proportion of this post-folding coalification is found to increase toward the south of the coalfield.
A late gravity-fault, exposed along the east crop of the coalfield, places high-volatile coal-bearing successions in contact with low-volatile coal and demonstrably is a reactivated thrust fault. Coalification at this locality occurred between these two different ages of faulting.
The variations in rank and the subtleties of the coalification pattern have, together with systematic changes in the maceral composition of coal seams, had a profound effect on coal quality in the coalfield. Coking coals with a variety of properties occur together with some coals that have no caking capacity.
Keywords: Coal preparation, Coalification, Rank gradients, Stratigraphy, Coal quality, Structural setting, Crowsnest coalfield.
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Summary: The methods generally applied to predict performance and financially evaluate beneficiation options are reviewed.
Typical costs for a western Canadian thermal coal operation are examined. Preparation—from truck dump to loadout— frequently amounts to over a quarter of total minesite costs. Failure to achieve projected yield—whether caused by mine or plant problems—substantially increases production costs because more coal has to be mined to meet a specific market...
Publication: CIM Bulletin
Author(s): STANLEY G. BUTCHER
Keywords: Coal preparation, Economics, Thermal coal, Washability data, Coal cleaning, Coal beneficiation, Plant performance.
Issue: 881
Volume: 78
Year: 1985
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Summary: The Coal Research Laboratory (CRL) of CANMET along with other research organizations in coal-producing countries envisage major benefits from computer applications in coal preparation. Some of these benefits are greater system flexibility, improved coal preparation plant performance efficiency and efficient utilization of manpower, all of which result in economic benefits. Computers can be applied for both on-line and off-line purposes; this paper focuses on the on-line applications from the...
Publication: CIM Bulletin
Author(s): A.I.A. SALAMA, M.W. MIKHAIL, R.J. MIKULA
Keywords: Coal preparation, Computer applications, Process control, Instrumentation, Automation, Coal flotation, Ash monitoring.
Issue: 881
Volume: 78
Year: 1985
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Summary: A very conductive zone was revealed in 1977 and 1978 by magnetotelluric (MT) measurements carried out near Ste-Mathilde, 6 km northeast of La Malbaie. In order to identify the structure causing the anomaly, thirty-five MT soundings were recorded in 1980 and 1981 on and around the conductor within a radius of 4 km. Results confirmed that the conductor is of limited extent (less than 2 km by 0.4 km). The proposed model is a highly conductive vertical slab, the top of which is within 200 m from...
Publication: CIM Bulletin
Author(s): MICHEL CHOUTEAU
Keywords: Mineral exploration, Technology, Magnetotelluric measurement, Electrical resistivity, Conductivity, Metallic mineralization, Electrolytic solution, Graphite veins.
Issue: 881
Volume: 78
Year: 1985
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Summary: Refractoriness in Carlin-type gold ores results mostly from fine locking of gold in pyrite, locking in various gangue phases, notably quartz, and a "preg robbing" condition attributed to organic carbon. All three conditions may occur in any given deposit, including Newmont's Carlin and Gold Quarry deposits in Nevada, where types of refractoriness occur locally in minor amounts.
Measurements of specific gravity, water absorption and screen size distributions of gold in alteration...
Publication: CIM Bulletin
Author(s): D.M. HAUSEN
Keywords: Mineralogy, Process mineralogy, Refractory ores, Gold mineralization, Gold, Water absorption, Specific gravity, Screen-size distribution, Metallurgy.
Issue: 881
Volume: 78
Year: 1985
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Summary: The paper describes current 'tools' available to the coal preparation engineer for carrying out the evaluation of data, process design, selection of equipment and layout and design of coal preparation plants.Laboratory and pilot-scale equipment is widely available and test data can be used to provide valuable design information regarding capacities and sizing for specific applications. Pilot plants, unless they fit closely to the basic design envisaged for the eventual commercial plant, can...
Publication: CIM Bulletin
Author(s): D.G. OSBORNE
Keywords: Coal preparation, Process Design, Computer Modelling, Plant design, Coal cleaning, Washability data.
Issue: 881
Volume: 78
Year: 1985
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Summary: A program of sampling in Canadian washeries was carried out by the Coal Research Laboratory (CRL) over a period of two years to evaluate the performance of various density separators in these operations "'. Operating data on quality and recovery of products, separation efficiencies and cutpoints for each separator type are compared with data predicted using computer models developed from previously existing data.The Heavy Medium Cyclone (HMC), Heavy Medium Bath (HMB) and jig models give...
Publication: CIM Bulletin
Author(s): A.I.A. SALAMA, M.W. MIKHAIL, LC. BIRD
Keywords: Coal preparation, Density separators, Coal washing, Washeries, Computer models.
Issue: 881
Volume: 78
Year: 1985
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