Precaution technology of gas in upper corner in 8919 fully mechanized mining work face in 11 coal seam in west second panel in Xinzhouyao coal mine是什么意思_Precaution technology of gas in upper corner in 8919 fully mechanized mining work face in 11 coal seam in west second panel in Xinzhouyao coal mine在线翻译_英语_读音_用法_例句