(a) Each payment shall be accompanied by an affidavit of the lessee or his authorized agent indicating:
(1) the amount of minerals produced and marketed during the month;
(2) the person to whom the minerals were sold; and
(3) the selling price for the minerals as shown by copies of the smelter, mint, mill, refinery, or other returns or documents attached to the affidavit.
(b) Books, accounts, weights, wage contracts, correspondence, and other documents or papers relating to production under this subchapter are open at all times to inspection by the commissioner or his authorized representatives.