Abstract: According to the running away accident occurred in the downward transportation process of the belt conveyor in the underground mine, the electric and hydraulic thruster in the previous belt conveyor system was replaced with a self cooling disk type brake .After the technical reconstruction with the self cooling disk type brake, the braking system could provide a smooth and no high impact braking torque, reduce the dynamic stress of the equipment and improve the stressed status of th e driving section structure component at the end of the belt conveyor. Under the sudden power failure or other emergency condition, the brake system would be automat ically in emergent braking and could ensure the smooth and reliable braking.In comparison with the technical reconstruction conducted before, the downward operation performances of the belt conveyor were obviously improved and there were no running away, belt broken, conveyor end buried with coal, vibration on the driving section structure component at the conveyor end, downward sliding after braking and other accident phenomenon occurred.