One of the Kentucky mine workers charged in a coal dust fraud case last year wants to change his “not guilty” plea to “guilty,” a possible indication that the defendant will cooperate with prosecutors in the case. Court documents show defendant Ron Ivy, a former employee of Armstrong Coal, is scheduled to change his plea on April 1. Ivy pleaded guilty last year along with eight others charged in an indictment. Western Kentucky District U.S. Attorney Russell Coleman says the case remains open and active. “Cooperation is very useful and is welcomed and it certainly will be beneficial to many of those that are, that know something, that have information as to this criminal conduct,” Coleman said. Earlier this week Coleman unsealed a new indictment against the former manager of all of the western Kentucky mines belonging to the now-bankrupt Armstrong Energy coal company. Glendal “Buddy” Hardison is charged with conspiring to defraud the United States and the Mine Safety and Health Administration. The indictment alleges Hardison met with Ron Ivy and ordered agents of Armstrong Coal to make sure the air monitoring pumps showed acceptable levels of coal dust even though the pumps were not properly used. Controlling coal dust is important both to prevent the potential for explosions in mines and to limit miners’ exposure to dust, which causes lung disease. The case comes amid a surge in cases of black lung disease.