Patent ID: 11959383
Assignee: TAIYUAN UNIVERSITY OF TECHNOLOGY
Field: Civil engineering (Other fields)
Classification: CPC E | IPC E

Claim 2:
3. The method of claim 1, wherein four grouting holes are arranged in each row on a floor of the return air gateroad; the four grouting holes in each row are respectively a first grouting hole, a second grouting hole, a third grouting hole and a fourth grouting hole from a first side of the floor of the return air gateroad to a second side of the floor of the return air gateroad; the first grouting hole is at an angle of 30° to the floor of the return air gateroad, and is inclined downward towards the first side of the floor of the return air gateroad, so as to extend into the stoping coal seam on the first side of the floor of the inlet air gateroad; the second grouting hole is at an angle of 30° to the floor of the return air gateroad, and is inclined downward towards the first side of the floor of the return air gateroad, so as to extend into the stoping coal seam above a roof of the inlet air gateroad; the fourth grouting hole is at an angle of 45° to the stoping coal seam at the floor of the return air gateroad, and is inclined downward towards the second side of the floor of the return air gateroad; and the third grouting hole is perpendicular to the stoping coal seam at the floor of the return air gateroad.