Large deformation control technology of gateway based on stress weakened hard roof

According to the dynamic pressure occurred by roof breaking during the mining period,a serious Large deformation failure phenomenon caused in the gatew ay of No. 7521 coal mining face in Yaoqiao Mine. The paper analyzed the features and causes of the Large deformation failure occurred. The paper pointed out that deep d epth and dynamic pressure occurred from hard roof breaking were two main factors to cause Large deformation failure. A hydraulic fracturing technology was provided to th e stress weakening of hard roof above gateway and to reduce pressure of surrounding rock. An engineering test was conducted in the mine site under condition not to incre ase the support intensity of the surrounding rock. The results showed that the application of the hydraulic fracturing technology could make the stress weakening of hard ro of and could well control stability of surrounding rock along gateway. The feasbility of new technology applied to large deformation control of gateway was approved.