Study on the influence law of gangue filling structure on the gas emission in adjacent coal seams

Abstract

Gangue filling affects the emission and migration of gas in adjacent coal seams by altering the distribution of mine pressure in the stope. In engineering practice, the filling rate of gangue in the goaf fluctuates under the influence of external factors, leading to the formation of filling structures. However, the relationship between different filling structures and the gas emission law of adjacent coal seams remains unclear. The parameters affecting the gangue filling structure can be controlled or optimized in field practice. Meanwhile, these parameters are not independent of but correlated with each other. This study aims to control gas emission and improve the gas extraction of adjacent coal seams. Therefore, the gangue filling structure index ξ was proposed, and the permeability evolution of adjacent coal seams under different ξ and parameters was analyzed. The respective and coupling effects of the parameters composing ξ were further investigated by response surface methodology. The results revealed the parameters that have dominant effects on pressure relief and permeability increase of adjacent coal seams and their sequence of importance. Finally, the study proposed a technology that combines targeted gas extraction with geophysical prospecting methodologies. The research results provide a theoretical reference for engineering practice.