开拓巷道 meaning in English

developement openings
developement workings
developing butt
development road
opening

Applied study of secondary support technique for development roadway in soft coal seam
软煤层开拓巷道二次支护技术的研究
Application on bolting with wire mesh technology of development roadway in district dip of
三软煤层采区下山开拓巷道锚网支护应用
The air amount calculation of long distance ventilation at one times blast in drifting big section rock roadway
大断面全岩开拓巷道一次起爆长距离通风风量计算
Application on bolting with wire mesh technology of development roadway in district dip of quot; three soft quot; coal seam
三软煤层采区下山开拓巷道锚网支护应用