TWO EE'S WERE MOVING A 8"" PLASTIC PIPE WHEN ONE HAD TRACKHOE OPERATOR ROLL BUCKET OUT AND BUCKET HIT INJURED'S RIGHT KNEE CAUSING SWELLING. EE WENT TO THE DOCTOR ON 10/3/00. DR SAID NO DAMAGE WAS DO, THAT THE SWELLING WOULD GO DOWN IN A FEW DAYS. EE RETURNED TO WORK.