Abstract: In order to solve the problem of roof and rib controlling of large mining height and island working face in three-soft coal seam in Xiaokang mine, the difference of roof controlling between island and normal working face were analyzed and contrasted based on the method of theoretical analysis and numerical modeling. The hydraulic support parameters were optimized. The results show that the stress, displacement, failure zone in island working face were more than the normal working face due to the influence of the both sides of the gob, which leaded to the difficult controlling of roof and rib. Based on the curve of supporting intensity and roof subside displacement, the supporting intensity of hydraulic support should not less than 1.3MPa. The setting load of hydraulic support should more than 1.0MPa through analyzing the curve of the setting load and rib horizontal displacement. The hydraulic support’s type is ZY13500/31/65, which adopted the telescopic girder and face guard structure. The height of the face guard is 3m. The structure of raising the base was designed to improve the adaptation to the floor.

Key words: three-soft coal seam, island working face, numerical modeling, supporting intensity, protection to help institutions.