INJURED STATED THAT HE WAS HELPING REMOVE A LARGE SULFUR BALL FROM THE FEEDER ON #1 UNIT WHEN HE FELT A PULL IN HIS GROIN AREA ON THE LEFT SIDE. INJURED CONTINUED WORKING AND WENT TO THE DR ON 10-29-01. HE RETURNED TO WORK THE NEXT DAY. HE WENT TO THE DR AGAIN ON 11-01-01. HE RETURNED TO WORK THE NEXT DAY.