Research on technique of forming roadway by advanced roof cutting and pressure releasing in depth buried coal seam with broken roof

In order to solve the waste of resources caused by the reserved coal pillars, based on the special conditions of deep burial and broken roof in Chengjiao Coal Mine, the feasibility of gob-side entry retaining by roof cutting and pressure releasing was studied based on the special conditions of broken roofs in Chengjiao Co al Mine. According to the geological condition of 21304 mining face, the directional pre-splitting blasting technology of the working face was supplemented by the const ant deformation and large deformation anchor, and the retaining road was supported along the working face coal wall 200 mm at the depth of 8 m, spacing 600 mm, and the vertical direction into a 15° pre-split hole for directional blasting; in the roof construction of two rows of 10 m long and away from the slit hole 300 mm, spacing400 mm, row spacing 700 mm and preload was not less than 280 k N constant resistance anchor for permanent support. The test section of the retaining roadway showed t hat gob-side entry retaining by roof cutting effectively reduced the influence of the large burial broken roof on the roof retaining stability, and the technology of gob-side entry retaining in large buried depth was achieved, which provided invaluable experience for the similar roadway.