EE was bldg kennedy stopping with 2nd ee. He was holding angle iron while other ee was driving into the rib. Rib fell knocking ee to the ground. He reported to have broken ribs and puncture lung. The area was in 13W, between sharline and x cut 18 1/2 in the #1 entry. Rib measured 13'L, 4'-6' wide and 9 1/2 high.