Black Hills Corp. announced changes in the composition of its board of directors. Warren L. Robinson, director since 2007, informed the board that, for personal health-related reasons, he will resign from the board effective with the annual meeting of shareholders on April 28, 2015.

Steven R. Mills, a current member of the audit committee, has been appointed audit committee chairman to be effective with Robinson's resignation. The board elected Linda K. Massman to the company's board of directors, effective immediately. She will serve on the compensation committee.

Since 2013, Massman has held the positions of president and chief executive officer of Clearwater Paper Corporation. The board also temporarily increased the size of the board from 10 to 11 directors until the effective date of Robinson's resignation to allow for a smooth transition in directors.