Carbon dioxide blasting method and its application for surface coal bunkers

Ground coal bunker blockage hinders production at a coal mine in Yulin City, Shaanxi Province, with wall adhesion and arching as two main types of blockage. This study proposes a carbon dioxide (CO2) blasting method as a solution to this problem. Force analysis revealed that the upper part of the adhesive coal mass and the center of the arch feature lower viscous friction, thus becoming key positions for unblocking. Comparative analysis showed that in dealing with wall adhesion blockage, the average number of air cannons required for unblocking was approximately 3.3 times that of the carbon dioxide blasting method. Coal drop was 0.97 t less, indicating the limited effect of the equipment's energy release pressure on unblocking. For arching blockage, air cannon usage was 3.0 times higher, with 5.83 t less coal drop than CO2 blasting. This demonstrates that CO2 blasting outperforms air cannons. The energy dissipation head of CO2 device should be as close as possible to the center of the arch bridge during unblocking. This CO2 blasting method proves to be a feasible technical approach for unblocking ground coal bunkers.