Blankenship was sent to jail after being convicted last December on one misdemeanour count following a five-year investigation into the 2010 explosion at Massey’s Upper Big Branch mine that killed 29 workers.

According to The Wall Street Journal, Blankenship has released a 67-page booklet calling himself a political prisoner and professing his innocence.

“The story is a little complex and telling it from prison without a computer and without much documentation has not been easy,” the WSJ quotes him saying.

“”But it is a story Americans need to know.

“You can be sure I am fully innocent. The real conspiracies were the government’s cover-up of the UBB truth and my prosecution.”

According to the WSJ a section of the booklet attributed to Blankenship’s lawyers argues that prosecutors manufactured the case against him despite a lack of evidence linking him to any criminal misconduct at Massey.

Blankenship has long argued that the UBB explosion was the result of an unforeseeable inundation of natural gas.

Federal and state investigators found the explosion to have been caused by a spark from a poorly maintained longwall shearer that ignited methane, which in turn set off an explosion fuelled by coal dust the company had not cleaned up.

A 2012 report by the Governor’s Independent Investigation Panel, headed by investigator Davitt  found the UBB mine tragedy could have been avoided.

“The tragedy at the Upper Big Branch Mine was entirely preventable, and basic safety practices were not followed by Massey Energy,” assistant secretary of labor for mine safety and health Joseph Main said.

Main said the major findings of the GIIP report matched up with much of the evidence analysed by the Mine Health and Safety Administration to date.

The GIIP report found Massey failed to properly examine the mine to find and fix hazards and violations; control the accumulation of coal dust in the mine by adequately rock dusting; maintain water spray systems on the longwall cutting shearer; submit an effective mine ventilation plan; and comply with approved plans.

“Massey promoted a culture that ‘prized production over safety’ and where ‘wrongdoing became acceptable’,” Main said.

“As such, it violated the law and disregarded basic safety practices

“As part of this culture, the GIIP report found that Massey employed tactics to intimidate miners from speaking out about unsafe conditions.”