Coal mining, which liberates the stuff from coal seams, is the second-biggest source of Chinese methane after agriculture.

开采从层中释放出物质，是中国仅次于农业的第二大甲烷来源。

Then, to reach the buried coal seams, explosives are used to remove up to 800 feet of mountain elevation.

然， 为了到达埋藏的层，使用炸药移除高达 800 英尺的山体高度。

You will then walk along the low passages cut in the coal seam, and you will see men with pick-axes breaking down and cutting out great blocks of the coal.

然你就可层中开凿的巷道走一走，会看见们拿镐头，把大块的砍下来，挖出来。