短語詞組短語first coal mining face 首采工作面conventional coal mining face 普采工作面coal working face 煤工作面thin coal seam face 薄煤層工作面Mechanized Coal Winning Face 機械化工作面mining coal work face 高檔工作面coal caving face 放頂煤工作面coal -face work 采煤工 返回 coal face