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

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

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

Blankenship's campaign vows to "vigorously challenge" any denial of efforts to be on the ballot.

Blankenship, who finished third in the Republican primary, 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.