THE INJURED EE WAS CLEANING THE #1 RAW MILL SAND TABLE DISCHARGE SHUTE WITH A PUNCH ROD. WHEN THE EE TURNED TO STEP DOWN OFF OF THE WEIGH BELT STRUCTURE HE STUMBLED OVER SOME MATERIAL CHUNKS L AYING ON THE PLATFORM AND FELL DOWN ABOUT 2 1/2 FEET TO THE FLOOR TWISTING HIS LEFT LEG AND FOOT. THE EE DIDN'T REPORT THIS INCIDENT UNTIL 7/5/00.