EMPLOYEE WAS FILLING BLASTING HOLES WITH ANFO FROM A CONVERTED READYMIX TRUCK. WHILE MONITORING THE FLOW OF ANFO DOWN THE CHUTE, THE SPRING LOADED CHUTE BECAME UNLATCHED AND PREMATURELY TRIED TO FOLD ITSELF UP. THE CHUTE HIT EMPLOYEE ON THELIP AND CHIN CUTTING HIM. STITCHES REQUIRED.