Part roof fall accident cause is analyzed in flase top mining in No.5 Coal Seam of Pinggang Coal Mine.The prevention and cure measures are pointed out.是什么意思_Part roof fall accident cause is analyzed in flase top mining in No.5 Coal Seam of Pinggang Coal Mine.The prevention and cure measures are pointed out.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句