下向分层进路回采
access-way stoping in the course of downward slicing
进路分层分条回采
slice drift and strip stoping
下向分层充填采矿法
Underhand cutting and filling method
下向进路采矿
underhand drift cut and-fill stopping
下向进路胶结充填采矿法
underhand drift cut-and-fill stoping
进路分层干式充填法
drift stoping method with dry backfill
空分下塔
Lower section of an air separation tower