A 2 1/4"" 3/4 drive socket was being used to tighten down lid bolts on primary crusher. The socket was being used with a 3/4 drive air ratchet. Miner was using his right hand to hold socket in place and his left hand to separate impact. Socket had a piece of chrome sliver peeling off of socket. It was about 1 1/2 inches long. The sliver went into the miners right hand.