被保护煤层
The research shows that long distance relief gas does not swarm into the working face in protective coal seam, but the permeability of protected coal seam increases thousands of times because of mining long distance nether protective coal seam.
研究表明:远距离下保护层开采后,远程卸压瓦斯基本上不会窜入保护层回采工作面,但被保护煤层的透气性系数得到数千倍的增大。
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