In the operation of mechanized undercut and fill mining technology,the stability of backfill isthe assurance of the production safety.

 
  • 采用機械化下向膠結充填采礦生產(chǎn)工藝,充填體假頂是采場(chǎng)生產(chǎn)安全的保證。
今日熱詞
目錄 附錄 查詞歷史
国内精品美女A∨在线播放xuan