Mechanic was injured while attempting to adjust a propeller on a barge pump propeller shaft in the shop for repair. 2 employees were using a 6' pipe on a pipe wrench to turn the propeller shaft of the pump. There was a burr on the end of the pipe. Wrench slipped & burr on the pipe cut EE's forearm. He was taken to ER-received 8 stitches to close the wound. full duty return.