Coal mine operators will have to store extra oxygen supplies underground and more quickly notify the federal Mine Safety and Health Administration of accidents under emergency rules the agency announced Tuesday.

Miners currently wear oxygen packs containing about one hour's worth of air. However, the emergency rule calls on companies to store extra packs in a readily accessible area for every miner.

The new emergency rule also says MSHA must get that call within 15 minutes of an accident.

Coal companies are supposed to call the agency immediately after an accident occurs. However, it took about two hours for MSHA to be notified of the Jan. 2 accident at the Sago mine in West Virginia.

The rule will require companies to make sure miners have "lifelines" along all primary and alternate escape routes. Those are guides, such as ropes with reflective tape, that help steer miners toward the surface during an explosion that leaves a mine dark.

David Dye, acting assistant secretary of labor for mine safety and health, said the emergency rule, a step the agency rarely takes, will better protect miners and help them safely evacuate during emergencies.