Alpha Natural Resources confirmed late Wednesday in a US Securities and Exchange Commission filing that an imminent danger order was given to its Sidney Coal subsidiary by the US Mine Safety and Health Administration for a hazardous condition at the Progress Energy mine.

The order alleged, officials said, that a worker was observed August 16 working in the red zone of a continuous miner at the complex near Sidney.

No injuries occurred as a result of the cited condition, and Alpha subsequently conducted additional training for its staff on red zone awareness.

Alpha did not release any further comment on the incident beyond the filing.

Imminent danger orders are issued by MSHA under section 107(a) of the Federal Mine Safety and Health Act, also known as the Mine Act.

Section 1503 of the Dodd-Frank Wall Street and Consumer Protection Act, amended last July, requires disclosure of all imminent danger incidents as part of reporting requirements regarding mine safety.

The last month has been a busy time for imminent danger orders at US operations resulting from especially worrying conditions. Last week Cliffs Natural Resources revealed a methane leak August 13 at its Pinnacle mine in West Virginia that forced the evacuation of its underground crews.

August began on a negative note with an August 3 announcement by Consol Energy that an ignition occurred at its Robinson Run longwall in West Virginia.

The producer did not indicate at the time the specific actions taken following the incident, but said the MSHA order was subsequently abat0ed.

No injuries were reported from that ignition.

The Sidney complex is among the properties Alpha received in its June 2011 takeover of Massey Energy. The producer announced layoffs from three Sidney mines and several other locations in late June, though Progress was not among the group.