Secure zone, dangerous zone, critical zone of No.9 coal s eam menaced by pressure water is defined, purpose is to offer precious firsthand datum for the safe production of Xiyu coal mine.

• 用隔水系数法,对受承压水的威胁的9号煤层的安全区、危险区、临界区进行了确定,目的是为西峪煤矿的安全生产提供宝贵的第一手资料。