Former Massey Energy chief executive Don Blankenship, left, makes his way out of the Robert C. Byrd U.S. Courthouse on Dec. 1, 2015 in Charleston, W.Va. Blankenship was charged with conspiring to break safety laws and defrauding mine regulators at West Virginia’s Upper Big Branch Mine, which exploded in 2010, killing 29 men. (Tyler Evert/Associated Press)

The unrepentant onetime Massey Energy chief executive Don Blankenship completed a one-year prison sentence this week and immediately took to Twitter and cable television to lambaste the people he says unfairly blamed him for the accident that killed 29 miners in April 2010.

Blankenship was convicted of conspiring to violate mine safety and health standards at Massey’s Upper Big Branch Mine, where the accident took place. He received the maximum jail sentence and was fined $250,000.

But Massey’s tweet storm since his release on Wednesday illustrates that even in the coal patch, bitter disputes and personal enmities can last a long time.

Blankenship was not charged with directly causing the disaster, but he was accused of violating a long list of safety standards including mine ventilation, roof support and dust control, measures that have been effective in preventing mine explosions.

And while a jury acquitted Blankenship of felony charges, several investigations into Upper Big Branch — including one by the Mine Safety and Health Administration and one by an independent panel set up by the governor — concluded that Massey’s pattern of safety lapses led to the accident.

Blankenship, however, blames the regulators. “Again one or the other lied. MSHA or prosecution witnesses. Which one is it?” he tweeted on May 11, referring to the Mine Safety and Health Administration, formerly headed by the former safety chief of the miners’ union Joe Main.

And Blankenship has aimed several tweets at Sen. Joe Manchin III (D-W.Va), who told ABC News in 2014 that Blankenship “has blood on his hands.” On Thursday, Blankenship tweeted that Manchin “said I conspired to commit safety violations that caused the death of 29 miners. Not true. He needs to apologize now.”

In another missive he added, “Chemistry and forensic science make the UBB truth clear. Political science made it necessary that the Joes – Manchin and Main hide truth.”

“A U.S. Senator who says I have ‘blood on my hands’ should be man enough to face me in public,” he said in another, challenging Manchin to a debate.

The feud with Manchin goes back 15 years. Blankenship opposed a bond offering that Manchin backed when he was governor. They also tangled over a film Blankenship produced about the mine disaster after he left the company.

Manchin’s office did not return a call or an email asking for comment.

“Don hasn’t changed one bit in his explanation of what actually happened or in the bias that went into this investigation and prosecution from the beginning,” said William Taylor, a partner at the law firm Zuckerman Spaeder who represented Blankenship. “And he’s right.”

“I think to Don’s credit he has not been cowed and he continues to believe that the truth has not really been told or if it has been it’s been obscured by the constant chorus that Massey was a dangerous place to work,” Taylor added.

Taylor noted that President Obama called the disaster a failure of management before investigators could even get inside the mine.

Blankenship has also responded to critics by saying that MSHA rules led to the mine explosion.

But the independent investigative panel blamed both the company and MSHA. It said that Massey “did not live up to that charge” to run a mine safely and the mine safety administration failed to crack down on violations.

In March 2010, one month before the accident, the Upper Big Branch mine received 50 citations — for poor ventilation of dust and methane, failure to maintain proper escape ways, and the accumulation of combustible materials.

The U.S. Mine Safety and Health Administration cited the mine for 1,342 safety violations from 2005 through the accident for a total of $1.89 million in proposed fines, according to federal records. The company has contested 422 of those violations, totaling $742,830 in proposed penalties, according to federal officials.

In sentencing Blankenship, a West Virginia judge cited the chief executive’s hard life story and said: “Instead of being able to tout you as one of West Virginia’s success stories, however, we are here as a result of your part in a dangerous conspiracy.”

An earlier version of this story mistakenly said that Joe Main was head of the mineworkers’ union. He was the head of safety for the union.