FALL OF ROOF OR BACK at Mammoth Coal Co.
Unplanned roof fall occurred at bottom of slope #4 entry at spad #206 track entry. The fall was approximately 30 ft. long x 18-19 ft. wide x 15 ft. high. No injuries or entrapment or equipment involved. No ventilation involved. Secondary escapeway blocked and it was changed around the fall.
U.S. Mine Safety and Health Administration