Blankenship has led Massey Energy as Chairman and CEO since 1992, and he’s been with the company since 1982.

“After almost three decades at Massey it is time for me to move on,” Blankenship said.

An outspoken U.S. coal industry executive, Blankenship routinely went toe-to-toe with environmental activists and organized labor. He used his clout (and his money) to affect change in regional politics.

Earlier this year, an explosion at Massey Energy’s Upper Big Branch mine killed 29 miners—the worst U.S. mining accident in 40 years. The results of the investigation from the tragedy and the eventually hearings have the potential to become a showdown between Massey Energy, the United Mine Workers of America, and the Mine Safety and Health Administration.