THE INJURED EE WAS WALKING FROM THE SECTION TRANSFORMER TO THE ROOF BOLTING MACHINE. AS HE WAS WALKING HE DISLODGED A 2' BY 2' SLAB OF COAL FROM THE RIB WHICH STRUCK HIS KNEE. NO CUTS OR BRU ISING OR SWELLING WAS VISIBLE. X-RAYS SHOWED NODAMAGE TO THE KNEE JOINT.