The US Mine Safety and Health Administration (MSHA) said it inspected three mines owned by Massey Energy for hazardous conditions in response to anonymous complaints.

MSHA inspectors issued multiple citations for serious violations after making surprise visits to the Massey Energy mines in West Virginia.

The agency seized telephone lines to prevent employees from alerting colleagues and ordered workers out of designated areas.

The MSHA said it received complaints about the West Virginia mines owned by Massey and run by Spartan Mining in Wyoming County and Inman Energy and Independence Coal in Boone County.

Spartan and Inman have received citations for inadequate ventilation while Independence Coal was cited for illegally cutting into the coal face.

The agency added that roof bolts at the Independence mine were sheared off and damaged, raising the risk of a collapse.

The Randolph mine’s operator, according to the MSHA, had not been providing an adequate amount of fresh air or taking effort to decrease coal mine dust enough to reduce the risk of explosion.

Meanwhile, Massey said it fired eight employees and another quit following the agency’s actions.

The disciplinary action has been taken against employees accused by the mine of going against its accountability and safety policies.