LAUSR

Abstract The spatio-temporal distribution and gas conductivity of overburden fissures in the mining of shallow thick coal seams are investigated to understand the correlation between the dynamic growth of overburden fissures in the mining of shallow thick coal seams and their gas conductivity. Theoretical analysis, numerical simulation and on-site measurements were combined for the mining of shallow thick coal seams in the Chuancao Gedan Mine. The results revealed that ground fissures with dynamic changes were observed periodically as the coalface moved forward. Dynamic changes of the horizontal fissure opening and vertical deformation related to the instability motion of the loading key stratum in the overburden were observed. The coalface mined-out area was divided into the fissure initiation, fissure propagation and fissure closure zones based on the changes in the horizontal opening and the vertical deformation of adjacent rocks in the overburden.