The principal office of the board shall be at the state capital, but it may sit or hold hearings at any other place in the state. A majority of the board shall constitute a quorum for making orders or decisions, promulgating rules and regulations necessary for the conduct of its powers and duties, or transacting other official business, and may act though one position on the board be vacant. One or more members may hold hearings and take testimony to be reported for action by the board when authorized by rule or order of the board. The board shall perform all the powers and duties specified in this chapter or as otherwise provided by law.