Although UBB is never directly mentioned in the document filed in U.S. District Court in Beckley, U.S. Attorney Booth Goodwin told The Associated Press the charges come from his team’s continuing and wide-ranging investigation of the April 2010 explosion that killed 29 men at the southern West Virginia mine. Hughart is the highest-ranking official yet to be charged, and his cooperation suggests that federal officials are aiming their sights even higher in the former Massey leadership.

The court document accuses Hughart of working with “known and unknown” co-conspirators to ensure that miners underground at White Buck and other, unidentified Massey-owned operations received advance warning about surprise federal inspections “on many occasions and various dates” between 2000 and March 2010. Four investigations have concluded that Massey systematically covered up problems at the mine through an elaborate scheme that included sanitized safety-inspection books and an advance-warning system.

Hughart could be the link prosecutors need to go up the Massey food chain. He’s been president of at least 10 Massey subsidiaries throughout his career and was known to be a confidant of Blankenship. Hughart has agreed to plead guilty to two charges: felony conspiracy to defraud the federal government by impeding the actions of MSHA, and misdemeanor conspiracy to violate mandatory health and safety standards. The felony charge carries a possible sentence of five years in prison, Goodwin said. The misdemeanor carries up to one year. Goodwin said his investigation is continuing, “and it’s clear from the information that there are co-conspirators, both known and unknown to us.”