The practice and procedure of the board with respect to any investigation by the board authorized by this chapter must be in accordance with rules and regulations to be promulgated by the board, which must provide for at least twenty days’ notice in writing to all persons affected by orders to be made by the board after such investigation, and an opportunity to be heard either in person or by counsel and to introduce testimony in their behalf at a public hearing to be held for that purpose. Notice of any such investigation or hearing must be given to all persons to be directly affected thereby in the manner and form provided in section 43-04-41. For the purposes of such investigation or any hearing which the board is authorized or required to conduct, the board or any members thereof, and its secretary, may conduct such hearing, administer oaths, take depositions, issue subpoenas, and compel the attendance of witnesses and the production of books, papers, documents, and testimony. In case of failure of any person to comply with any order of the board or a subpoena issued by the board, or by any of its members, or its secretary, or on the refusal of a witness to testify to any matter regarding which the witness may be lawfully interrogated, the district judge of the county in which the person resides, on application of any member of the board, or its secretary, by order duly entered, may require the compliance of such person with any such order, and may enforce such compliance as in the case of disobedience of the requirements of a subpoena issued from such court, or of a refusal to testify therein. Each officer who serves a subpoena shall receive the same fees as a sheriff, and each witness who appears in obedience to a subpoena, before the board or a member, or its secretary, shall receive for attendance the fees and mileage provided for witnesses in civil cases in the courts of this state, which must be audited and paid in the same manner as other expenses are audited and paid, upon the presentation of proper vouchers approved by any two members of the board. No witnesses subpoenaed at the instance of a party other than the board, or one of its members, or its secretary shall be entitled to compensation unless the board certifies that this testimony was material to the matter investigated.