In the progress of tunnelling of track dip in No.9 coal of Kangda mine at Xingtai,defective sectors such as abandoned old goaf are possible to be encountered.

• 邢台康达煤矿9煤轨道下山掘进过程中,可能会遇到废弃老空区等不良地段,将面临松散破碎围岩条件下的支护难题。