A CENTER BOLTER WAS BEING TRAMMED UNDER LINE CURTAIN. EMPLOYEE WAS ON THE OTHER SIDE OF THE CURTAIN ATTEMPTING TO PULL FREE A PIECE OF CURTAIN THAT WAS CAUGHT BY THE BOLTER. HIS LEFT LOWER LE G GOT PINCHED BETWEEN THE BUMPER OF THE CENTER BOLTER AND BUNDLE OF ROOF BOLTS PLACED AGAINST THE RIB.