Study on the mining dust release behavior under the top coal continuous caving coupling the dynamic hydraulic support advancing

Abstract

To elucidate the mining dust release rule at the synchronous sequence of hydraulic support advancing and top coal caving, a full-size mining face is constructed based on the discrete element model (DEM). Research results indicate that the caved coals integrate the original chaotic flow pattern into a cluster downstream high velocity field in the goaf. The goaf particles driven by the high velocity field mix with roof particles. The dust pollution length displays an increase trend and accumulates in the goaf, top beam and roof. The high concentration dust tends to accumulate at an upper location and the pollution area proportion increases from 0.03 % to 22.70 % with height for concentration exceeding 200 mg/m³. The dust pollution area at the stand breathing zone surges in the advancing event, while the dust outbreak persists for the longer duration and larger scale downwind. In the crouch operation, the mean dust concentration peaks at eight positions ranging from 16.875 m to 41.375 m in the X direction with the maximum of 116.57 mg/m³. The identification of the dust release path and pollution scope delineation contributes to the precise mining dust prevention at the top coal continuous caving coupling the dynamic hydraulic support advancing.