exposed coal seam meaning in Chinese

裸露的煤层

Reducing operation period of exposing coal seams in a crosscut by non - uniform hole layout
非均匀布孔缩短石门揭煤工期
Application of deep - hole pre - splitting blast and coal body reinforcement technique by metal skeleton and grouting in a face by crosscut for exposing coal seam
深孔控制预裂爆破与金属骨架注浆加固煤体技术在石门揭煤工作面的应用