Abstract: The sublevel open stoping with subsequent backfilling is adopted in Hemushan Mine.Since some mined-out areas are formed after the room is mined to be a certain stage, the roof caving and pillar collapse happened, resulting in high ore dilution rate and low the recovery rate.Through analysis, poor ore-rock stability is the main factor of causing the roof caving and pillar collapse.The upward horizontal stoping with backfill can effectively reduce ore dilution and improve ore recovery.

Key words: Upward horizontal drift stoping with backfill, Ore-rock stability, Caving, Collapse