The Federal Mine Safety and Health Administration issued an advisory to its 11 District Offices to check for any missing stoppings in other mines . Inspectors were advised that two such walls — each long and high — were missing in the Alma mine when investigators arrived . If the wall sections had been in place , they would have prevented any exchange of air between the conveyor belt and the fresh air intake , the primary source of air for workers inside the mine . Instead , investigators now believe , smoke flooded into the air intake , which also serves as an escape route , disorienting two of the miners , who became lost and died in the fire . The accident followed national media attention of the Sago Mine disaster , which occurred earlier in the month
Sago Mine disaster
Sago Mine disaster
Aracoma Alma Mine accident