Instantaneous outbursts in underground coal mines: An overview and association with coal type

Beamish, BB and Crosdale, PJ (1998) Instantaneous outbursts in underground coal mines: An overview and association with coal type. International Journal of Coal Geology, 35 1-4: 27-55. doi:10.1016/S0166-5162(97)00036-0


Author Beamish, BB
Crosdale, PJ
Title Instantaneous outbursts in underground coal mines: An overview and association with coal type
Journal name International Journal of Coal Geology   Check publisher's open access policy
ISSN 0166-5162
Publication date 1998-01-01
Sub-type Article (original research)
DOI 10.1016/S0166-5162(97)00036-0
Open Access Status Not yet assessed
Volume 35
Issue 1-4
Start page 27
End page 55
Total pages 29
Language eng
Abstract Instantaneous outbursts in underground coal mines have occurred in at least 16 countries, involving both methane (CH4) and carbon dioxide (CO2). The precise mechanisms of an instantaneous outburst are still unresolved but must consider the effects of stress, gas content and physico-mechanical properties of the coal. Other factors such as mining methods (e.g., development heading into the coal seam) and geological features (e.g., coal seam disruptions from faulting) can combine to exacerbate the problem. Prediction techniques continue to be unreliable and unexpected outburst incidents resulting in fatalities are a major concern for underground coal operations. Gas content thresholds of 9 m(3)/t for CH4 and 6 m(3)/t for CO2 are used in the Sydney Basin, to indicate outburst-prone conditions, but are reviewed on an individual mine basis and in mixed as situations. Data on the sorption behaviour of Bowen Basin coals from Australia have provided an explanation for the conflicting results obtained by coal face desorption indices used for outburst-proneness assessment. A key factor appears to be different desorption rates displayed by banded coals, which is supported by both laboratory and mine-site investigations. Dull coal bands with high fusinite and semifusinite contents tend to display rapid desorption from solid coal, for a given pressure drop. The opposite is true for bright coal bands with high vitrinite contents and dull coal bands with high inertodetrinite contents. Consequently, when face samples of dull, fusinite-or semifusinite-rich coal of small particle size are taken for desorption testing, much gas has already escaped and low readings result. The converse applies for samples taken from coal bands with high vitrinite and/or inertodetrinite contents. In terms of outburst potential, it is the bright, vitrinite-rich and the dull, inertodetrinite-rich sections of a coal seam that appear to be more outburst-prone. This is due to the ability of the solid coal to retain gas, even after pressure reduction, creating a gas content gradient across the coal face sufficient to initiate an outburst. Once the particle size of the coal is reduced, rapid gas desorption can then take place. (C) 1998 Elsevier Science.
Keyword Energy & Fuels
Geosciences, Multidisciplinary
Instantaneous Outbursts
Coal Mine
Gas Emission
Coal Lithotype
Differential Desorption
Gas Content Gradient
Gas
Model
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Mechanical & Mining Engineering Publications
 
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Created: Mon, 13 Aug 2007, 20:29:24 EST