THE EMPLOYEE AND HIS CO-WORKER COMPLETED BOLTING A CUT AND WERE WAITING ON THE MECHANIC TO CHANGE A HOSE ON THEIR MACHINE. THE EMPLOYEE WAS STANDING ON THE OPERATOR'S SIDE OF THE MACHINE AND A ROCK (12 IN X 8 IN X 2 IN THICK) FELL FROM THE TOP AND STRUCK HIS RIGHT SHOULDER. X-RAY NEGATIVE, BRUISE AND RESTRICTED DUTY.