Coal producer Alpha Natural Resources says the chairman of its board of directors is stepping down.

The Bristol, Va.-based company said Tuesday that Michael J. Quillen has chosen not to stand for re-election at the company's 2012 annual meeting.

The 63-year-old Quillen formed Alpha Natural Resources in 2002. He led the company through its initial public offering in 2005 and more than a dozen mergers and acquisitions. Quillen has served as chairman since 2006 and as a board member since 2004.

The board has selected CEO Kevin S. Crutchfield to succeed Quillen as chairman immediately following the May 17 annual meeting.

Alpha Natural Resources Inc. has more than 180 mines and processing plants in Kentucky, Pennsylvania, Virginia, West Virginia and Wyoming. It employs about 14,000 people through its affiliates.