According to the criteria, natural fracture zones of No.3 coal seam are divided into four grades and then the permeability distribution of No.3 coal seam is preestimated.
According to the criteria, natural fracture zones of No.3 coal seam are divided into four grades and then the permeability distribution of No.3 coal seam is preestimated.
依据该标准将3号煤层天然裂隙划分为4级发育区，进而预测出3号煤层渗透率的分布概况。