Former coal executive Don Blankenship – who spent a year in a federal prison over safety violations after 29 workers died in an explosion at his West Virginia mine in 2010 – has filed paperwork to seek the U.S. presidency in 2020 as a third-party candidate.

Blankenship will seek the nomination of the Constitution Party when it convenes next spring, Ballot Access News reported this week. He reportedly disclosed his plans in October at the party’s national committee meeting in Pittsburgh.

TRUMP COMES OUT AGAINST BLANKENSHIP IN WEST VIRGINIA SENATE RACE, SAYS HE 'CAN'T WIN'

Massey Energy Company Chief Executive Officer Don Blankenship pauses as he testifies on Capitol Hill in Washington, May 20, 2010. (Associated Press)

The 69-year-old Kentucky native has long been a Republican and contributed to conservative candidates. But The Intelligencer in Charleston, W.Va., notes that he was registered as a Democrat back in May – likely in hopes of challenging U.S. Sen. Joe Manchin, D-W.Va., who was thought at the time to be considering a run for governor.

Blankenship had previously run as a Republican for a U.S. Senate seat in West Virginia, but after losing in the GOP primary he was blocked from representing the Constitution Party in the general election under the state’s “Sore Loser Law,” which prevents candidates from switching parties to get on a general election ballot after losing a primary.

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The coal executive later blamed his GOP defeat in part on Donald Trump Jr., who reportedly incorrectly called Blankenship an “ex-felon,” prompting Blankenship to sue the president’s son. A trial date has been set for October 2020, The Intelligencer reported.

The Associated Press contributed to this story.