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Abstract In general，a coal bump refers to a sudden and violent failure of a coal seam that releases contained elastic energy and expels a large amount of coal and rock into the roadway or working face where men and machinery are present. Coal bumps occur more frequently in an island longwall panel，which is surrounded by previously mined panels，than in other longwall panels because of its high-stress concentration. Based on the geological conditions of island longwall panel in the Tangshan coal mine in Tangshan，China，numerical simulations were conducted to investigate the dynamical character of elastic strain energy relief and to understand the mechanism of energy explosion during periodic weighting of the island longwall panel. The advance of mining will cause continuously increasing of the goaf space because of the constant collapse of immediate roof. The accumulated elastic strain energy in main roof will abruptly release when the periodic weighting occurs. At this moment，the coal bumps occur more frequently. Numerical results suggest that elastic strain energy explosion of main roof and coal seam during periodic weighting is considered to be an important precursor of coal bump occurrence during the extraction of an island longwall panel. Therefore，it can be revealed that the one of significant reason of occurrence of coal bump is the suddenly elastic strain energy explosion during the periodic weighting of main roof. Based on these analyses，microseismic observation can be chosen to forecast the occurrence of coal bumps. Additionally，technology of forced roof caving and stress relief in coal seam is effective method to prevent the coal bump of island longwall panel.
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Received: 20 May 2013
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2013, Vol. 32 
