Abstract: According to the engineering geological conditions of a shaft in Gushan coalmine(Inner Mongolia) and the technical difficulties of grouting into media with micro pores,suitable materials and technology were applied to a 300m section. The hydraulic discharge was reduced from 37 m 3/h to less than 5 m 3/h. Samples of shaftwall and rocks were collected before and after grouting. The pore structure of the samples was analyzed by SEM and mercury penetrometer. The reason why the latest grouting is successful and preceding ones were unsuccessful is explained.