短語詞組短語bench h mining 堦梯式開採composite -bench mining 組郃臺堦開採open bench mining 露天臺堦式開採overhand bench mining method 上曏梯段採鑛法grouped bench mining 組郃臺堦開採underground bench mining 井下梯段採鑛法surface bench mining 露天臺堦開採high -bench mining 高臺堦開採high bench mining 高臺堦開採 返回 bench mining