If the funds available for use by the board are inadequate to enable it to undertake the expense of any proceeding under this chapter or if in its judgment reimbursement for the expense of any such proceeding is not reasonably certain, it may refuse to proceed with its investigation and to undertake the proceeding, unless and until such provision is made by persons interested as may be satisfactory to the board and deemed by it sufficient to secure reimbursement or payment to it for its expenses.