subparagraph (C). (B) Underpayment In the case of an underpayment, interest shall be computed and charged only on the amount of the deficiency and not on the total amount, at the rate specified under subparagraph (C). (C) Interest rate In the case of nonpayment or underpayment, interest shall be charged at the rate applicable under section 6621(a)(2) of the Internal Revenue Code of 1986. (g) Expanded royalty obligations Each person liable for royalty payments under this section shall be jointly and severally liable for royalty on all locatable minerals lost or wasted from a mining claim located under the general mining laws and maintained in compliance with this Act if the loss or waste is due to negligence on the part of any such person or due to the failure to comply with any rule, regulation, or order issued under this section. (h) Hearings and investigations In carrying out this title and section 403, the Secretary may— (1) conduct any investigation or other inquiry necessary and appropriate