EE WAS SUPERVISING REHABILITATION WORK IN THE MAIN EAST RETURNS. HE WAS OBSERVING THE ROOF BOLTER OPERATOR INSTALL A ROOF BOLT WHEN A LOOSE ROCK ROLLED OFF THE RIB AREA, STRIKING INJURED EE ON THE LEFT LEG & ANKLE. EE WAS TREATED IN THE HOSPITAL FOR A POSSIBLE BLOOD CLOT. HE STARTED MISSING TIME ON 02/06/04 & IS STILL UNDER THE DR.'S CARE AT THIS TIME. EE SHOULD ALWAYS CHECK AREA.