EMPLOYEES WERE REPLACING LINERS FOR THE FEEDER. EE WAS EXITING THE SURGE POCKET OF THE FEEDER BELT CRAWLING ON HIS HANDS AND KNEES WHEN SOME MATERIAL DISLODGED COMING DOWN AND COVERING BOTH HI S LEGS APPROXIMATELY TO MID-THIGH. THE FORCE OF THE MATERIAL CAUSED EMPLOYEE TO FALL FORWARD. HIS LEFT HAND SLID, CAUGHT ON THE BELT RUBBER SURFACE & THEN ROLLED UNDER HIS WRIST CAUSING INJUR