FALL OF ROOF OR BACK at Mammoth Coal Co.
An unplanned roof fall occurred on the north east mains, #2 belt break #27, #4 to 5 entry survey station #02978. Area of fall was developed 1-4-11, and supported with 48"" resign bolts, it is 6600' from active section. Fall measured 75' wide x 19'L x 4-8'H. Passage of persons was affected, ventilation was not affected, fall area will be rehabilitated.
U.S. Mine Safety and Health Administration