This kind of micromanaging is key to understanding Mr. Blankenship’s legal peril.

“One reason that Blankenship is being prosecuted is that he was different than other top coal executives,” said Patrick McGinley, an author of the state’s report on the disaster and a professor at West Virginia University College of Law. “Most C.E.O.s don’t get production records every half-hour by fax. That places him right in the mine, hands on. That makes him vulnerable.”

Mr. Blankenship is also the reason regulators were unable to improve safety at Upper Big Branch, according to prosecutors. As they dryly noted in the indictment, none of those hurry-up memos made any reference to safety, even though the mine was cited about 500 times by the federal Mine Safety and Health Administration in the year before the disaster. Many of the citations were for “significant and substantial” violations, defined by the agency as “reasonably likely to result in serious injury or illness.” The ventilation system was a consistent target, yielding 61 citations in the two years before the explosion.

Mr. Blankenship states in the “Never Again” video that the ventilation system at Upper Big Branch was the only one that the agency would approve, and that it was far inferior to the one that he and his engineers had wanted to install. M.S.H.A. vehemently denies this. Records filed in court in early May suggest that Mr. Blankenship was privately relieved that the agency was trying to impose its will. The filings revealed that Mr. Blankenship had secretly recorded hundreds of hours of conversations in his office. During one of those conversations, in November 2009, he told Massey’s chief operating officer: “Sometimes I’m torn with what I see about the craziness we do. Maybe if it weren’t for M.S.H.A., we’d blow ourselves up.”

No matter what caused the disaster, the details of it left experts stupefied. It sounded to them like a fiasco from another era.

“We haven’t had a coal dust explosion in 20 years,” said Celeste Monforton, a former M.S.H.A. policy adviser who now teaches at George Washington University. “They are completely preventable, and everybody knows it. Coal dust explosions happen in the Ukraine and China. Not the United States.”

‘Massey’s Way’

Mr. Blankenship was raised in Delorme, W.Va, an unincorporated railroad-depot town straddling the Tug Fork river. His mother, Nancy McCoy, conceived him while her husband was at war in Korea and he never met his biological father, according to an account in “The Price of Justice: A True Story of Greed and Corruption,” a book by Laurence Leamer about an epic lawsuit against Massey. The couple split, and Ms. McCoy used money from the divorce settlement to buy a small gas station and convenience store. Don and his siblings were raised in an unfinished cinder-block home so close to the railroad tracks that he could almost touch the trains.

“As the saying goes, we were poor and we didn’t know it,” Mr. Blankenship wrote on an autobiographical website. “We had an outhouse that was nicer than the one most of our neighbors had. We always had shoes.”