ST. CLAIRSVILLE, Ohio (AP) – Robert Murray, who as a leader of the largest privately owned U.S. coal operator long fought federal regulations to reduce black lung disease, has died. A lawyer tells The Intelligencer/Wheeling News-Register that Murray died Sunday at age 80 at his home in St. Clairsville, Ohio. He had announced his retirement Oct. 19 from American Consolidated Natural Resource Holdings Inc. as board chairman. The company sued unsuccessfully in 2014 over regulations to cut coal dust in mines to reduce black lung disease. No official cause of death was given. But recent reports stated Murray had applied for black lung benefits with the U.S. Labor Department.