Paradoxically, Mr. Blankenship’s own political influence has played out on an epic scale. His manipulation of West Virginia’s highest court in a civil case against him was rebuked by the United States Supreme Court in 2009, and inspired the John Grisham novel “The Appeal.”

Image Donald L. Blankenship Credit... Carolyn Kaster/Associated Press

Many family members of Upper Big Branch victims feared, in the nearly five years since the explosion, that Mr. Blankenship would never be held accountable because of his power and money.

As the United States attorney pursuing the case, R. Booth Goodwin II, won convictions of four lower-ranking Massey executives, miners’ families and others saw them as scapegoats. “Don Blankenship is a very powerful person; he won’t see a day in prison, I promise you that,” Jonathan Hughart, the son of David Hughart, a Blankenship lieutenant convicted last year, said at the time.

But all along, prosecutors were pressuring top executives to cooperate and establishing a paper trail tying Mr. Blankenship to daily decisions at Upper Big Branch. It is meant to refute any claim that he was too senior to have been involved in the disaster, which a state investigation traced to a corporate “culture in which wrongdoing became acceptable, where deviation was the norm.”

The 43-page grand jury indictment paints a portrait of Mr. Blankenship, 64, as a mine boss out of Dickens. He demanded a report every 30 minutes — including by fax to his home on nights and weekends — tallying up coal production in a section of Upper Big Branch that was one of the most profitable, producing $600,000 of coal a day.

Mr. Blankenship overrode managers who sought to strengthen roofs to prevent cave-ins or install ventilation systems to prevent explosions, ordering them to ignore “construction jobs” and instead to “run coal.”