Static and dynamic distribution characteristics and migration law of gas in goaf of short distance coal seams

Abstract

In order to prevent and control the emission of toxic and harmful gases in the goaf of close coal seams, it is of great significance to study its distribution and migration behavior. Taking 1818 working face of Jinshen Shaping Coal Mine in Shanxi Province as an example, the gas composition and volume fraction of equal interval measuring points in goaf and working face are obtained by arranging beam tube monitoring system and manual sampling method. By studying the spatial distribution of the gas in the upper and lower coal seams before and after the solid coal mining of the lower coal seam, the static and dynamic distribution laws of the gas in the upper and lower goafs within the range of 90 m in front of the goaf and 180 m behind the goaf are obtained respectively. Based on the spatial and temporal distribution characteristics of the gas in the upper and lower goafs, the four aspects of the migration mechanism of the gas in the goaf of the close-distance coal seam mining are discussed. It is found that during the mining process, the toxic and harmful gases in the close-distance goaf show a significant spatial and temporal distribution law of agglomeration to the return air side due to the multiple effects of air leakage diffusion, gas migration effect in the upper and lower goaf and coal-oxygen reaction.

Keywords

• close coal seams
• gas prevention and control
• static distribution
• dynamic distribution
• gas migration law