WHILE SHOVELING CRUSHED STONE FROM A CONVEYOR BELT, WHICH HAD STALLED AND BECOME OVERLOADED, IN PREPARATION FOR RESTARTING THE CONVEYOR, EE STATES THAT HE TURNED TO DISPOSE OF A SHOVEFUL OF ST ONE AND FELT A PAIN INHIS BACK WHICH SUBSIDED. STIFFNESS AND PAIN SET IN THAT EVENING. HESOUGHT MEDICAL ATTENTION THE FOLLOWING DAY AND WAS OFF WORK A TOTAL OF 3 DAYS.