Section 971.415 - Duration of a permit(a) Unless suspended or revoked pursuant to §§ 971.406 and 971.417 , each commercial recovery permit will be issued for a period of 20 years and for so long thereafter as hard mineral resources are recovered annually in commercial quantities from the area listed in the permit.(b) If the permittee has substantially complied with the permit and its associated recovery plan and requests an extension of the permit, the Administrator will extend the permit with appropriate TCRs, consistent with the Act, for so long thereafter as hard mineral resources are recovered annually in commercial quantities from the area to which the recovery plan associated with the permit applies. The Administrator may make allowance for deviation from the recovery plan for good cause, such as significantly changed market conditions. However, a request for extension must be accompanied by an amended recovery plan to govern the activities by the permittee during the extended period.(c) Successive extensions may be requested, and will be granted by the Administrator, based on the criteria specified in paragraphs (a) and (b).