CHARLESTON, W.Va. (AP) — Former coal executive Don Blankenship has filed paperwork to run in West Virginia's U.S. Senate race as the Constitution Party's nominee.

The Charleston Gazette-Mail reports Blankenship filed the documents at the secretary of state's office Tuesday with signatures of an estimated 11,000 registered voters.

Blankenship's campaign has said it will "vigorously challenge" any denial of his efforts to be on the ballot.

It's unclear whether the bid violates West Virginia's "sore loser" law, which prohibits major party primary candidates who lose from switching to a minor party.

Blankenship finished third in the Republican primary. He wants to join Republican Patrick Morrisey and incumbent Democratic Sen. Joe Manchin on the November ballot.

Blankenship is a former CEO of Massey Energy, which owned a mine where a 2010 explosion killed 29 miners. He spent a year in federal prison for violating safety regulations.