43 C.F.R. § 3207.10
What is the primary term of my lease?
(a) Leases have a primary term of 10 years.
(b) BLM will extend the primary term for 5 years if:
(1) By the end of the 10th year of the primary term in paragraph (a), you have satisfied the requirements in § 3207.11; and
(2) At the end of each year after the 10th year of the lease, you have satisfied the requirements in § 3207.12(a) or (d) for that year.
(c) BLM will extend the primary term for 5 additional years if:
(1) You satisfied the requirements of § 3207.12(b) or (d); and
(2) At the end of each year of the second 5-year extension you satisfy the requirements in § 3207.12(c) or (d) for that year.
(d) If you do not satisfy the annual requirements during the initial or additional extension of your primary term, your lease terminates or expires.