EE STATED THAT HE WAS GETTING ON THE DOZER TO WORK. HE STEPPED UP ONTO PUSH BEAM STEP WHERE COAL WAS PILED ON TOP OF IT. HIS FOOT SLIPPED OFF CAUSING HIM TO HIT HIS LEFT KNEE AGAINST THE STEP. KNEE STARTED SWELL8ING ABOUT 3 WEEKS LATER. WENT TO DR. ON 1-3-2001. NOT REPORTABLE UNTIL LOST TIME INCURRED ON 1-31-2001.