Shares of Ramaco Resources declined after the company disclosed that former U.S. Senator Joe Manchin had stepped down from its board.

Class A shares of the company were down 5.2% to $11.64 in Thursday afternoon trading, having shed 35% this year. Class B shares were off 3.2% at $6.34, down 45% year-to-date.

The Kentucky-based coal producer said Thursday that Manchin, who represented West Virginia in the Senate until 2025, left the board to focus more on his independent leadership council movement with his daughter. His last day was Sept. 4, according to a Thursday regulatory filing.

"Senator Manchin's insight, experience and commitment to American energy, industry and economic security added tremendous value to our work," Chief Executive Randall Atkins said.

Manchin, a registered Independent who had been a Democrat for most of his career, said he will continue to support Ramaco and help the company succeed despite leaving the board.