Adopting gob_side entry and packing wall in the middle road at double_unit face in thin seam are introduced, and the economic benefit is analyzed.

 
  • 薄煤层对拉工作面中巷采用沿空留巷、砌充填墙的维护方法,并进行了经济效益分析。
今日热词
目录 附录 查词历史