Under gassy coal seam condition, the full-heading development is employed. Because of the fast heading a high rate of gas emission arises.
在瓦斯含量较大的煤层采用综掘掘进巷道，由于掘进速度快，出现了瓦斯涌出量过大的现象。
2
Gas drainage in high gassy coal seam with low gas permeability is always an hard solved significant technology problem in the process of safety production.