The board shall give public notice, in the official county newspaper or newspapers in the area of the state reasonably expected to be affected by operations conducted under a permit, that it is considering an application for such permit, and, if objection to the issuance of the permit is received by the board within twenty days, the board may hold a public hearing for the purpose of obtaining information from the public concerning the effects of issuing the permit. The board may also hold such hearings upon its own motion.