EE was attempting to remove some draw rock off top of cont. miner. EE grabbed a piece of rock measuring 30""L x 24""W x 5"" thick & pulled it toward body. When rock reached edge of machine EE lost grip, rock dropped down & caught front part of ring finger on rt hand against edge of machine severing most of the flesh toward the bone. EE was working in no. 6 entry w/2 co-workers.