According to a filing by Alpha with the US Securities and Exchange Commission, the alleged violation occurred at the company’s Madison underground mine in Cambria County, Pennsylvania.

While an Alpha spokesperson did not respond to an ILN request for more details by press time, the SEC filing confirmed that the safety policy for its Amfire Mining subsidiary – operator of the 75-employee Madison mine – prohibits workers from entering such areas.

Alpha said in the documentation that it would appeal the citation before the Federal Mine Safety and Health Review Commission.

Madison, a room and pillar operation, produces about 500,000 tons per year.