There was an inverse"C"shape crack zone ahead of mining face where methane was active.

认为工作面前方煤体存在反的＂C＂形裂隙发育带，是瓦斯流动活跃区域。

youdao

There was an inverse"C"shape crack zone ahead of mining face where methane was active.

认为工作面前方煤体存在反的＂C＂形裂隙发育带，是瓦斯流动活跃区域。

youdao