Prevention and control technology for spalling and failing of high inclined broken roof in fully mechanized mining face

The seam roof of No.311 fully mechanized coal mining face in Wutongzhuang Mine was broken and the inclination of the mining seam was upto 20 ~ 30°.The accidents of serious spalling of coal wall and roof falling of the coal mining face were often occurred.With the chemical grouting and reinforced technology for the coal and rock masses,the stability of the coal and rock mass was improved and the roof accidents due to the coal wall spalling was eliminated,which had ensured the successful mining operation of the coal mining face.