A former superintendent of the Upper Big Branch mine says his lawyer was ineffective, had conflicts of interest and made him a scapegoat for the disaster that killed 29 men in 2010.

Gary May wants U.S. District Judge Irene Berger to set aside or change the 21-month sentence he's serving at the Federal Correctional Institution at Morgantown.

May says defense attorney Tim Carrico refused to let him testify that illegal advance warning of inspections was common practice at Massey Energy operations now owned by Virginia-based Alpha Natural Resources.

Carrico didn't immediately return a phone message Tuesday.

May says he was muzzled to protect Massey executives from prosecution, and that longtime Massey general counsel Shane Harvey directed Carrico's actions.

Harvey denied that and said he was not involved in May's case.