All mines involved were owned by miner Massey Energy which was bought by Alpha Natural Resources last year.

The Mine Safety and Health Administration has not yet posted results from the surprise inspections, but indicated a safety incident at an Alpha operation earlier this month prompted the blitz.

On May 18, a smoking conveyor belt at Alpha’s Road Fork No. 51 mine in West Virginia resulted in an imminent danger but no injuries or further citation.

Withdrawal of miners was ordered at the site and the required foremen remained underground to locate the source of the smoke, though no fire was discovered.

Alpha subsequently terminated the order from MSHA on May 21.

An MSHA spokesperson told the Associated Press no violations in last week’s flurry of inspections was as serious as the Road Fork incident, but an official report was still pending government review.

West Virginia, Virginia and Kentucky have been identified as the three states targeted by the one-day inspection blitz, but reports regarding specific operations are not yet available.

The mines targeted by MSHA represent some 30% of Alpha’s operating coal mines.