TO INSTALL A TUNNEL LINER, ROOF BOLTS HAD TO BE CUT TO REMOVE A HEADER. GAS TESTS WERE CONDUCTEDUP TO A HEIGHT OF 6 1/2' IN #5 ENTRY OF SECTION 003. THERE WAS A CAVITY 11 1/2' ABOVE HEADER WER E GAS HAD ACCUMULATED. WHEN OXY/ACET. TORCH CUT THROUGH ROOF BOLT IT IGNITED GAS. ONE EMPLOYEE HAD SOME 1ST & 2ND DEGREE BURNS ON FACE.