The RB #10 mine was on retreat mining. The continuous miner was in the 2nd lift in the 3 entry left pillar about 30 feet into the pillar. A piece of rock fell onto the Emico miner that was 5 feet thick on the miner cutter head and 3 feet thick on the miner tail. The measurement was 5' to 3' thick, 12' wide and 25' long. The rock did not fall into the entry or pull any bolts.