短語詞組短語advancing and mining workface 采掘工作面advancing g mining 前進式開采longwall advancing mining mining 長壁式開采advancing coal mining 前進式采煤longwall advancing mining workings 長壁開采法longwall advancing mining stoping 長壁采礦法longwall advancing mining slicing 長壁分層采礦longwall advancing mining retreating 長壁后退式回采longwall advancing mining method 全面采礦法 返回 advancing mining