30 CFR § 761.12 - Exception for existing operations.
The prohibitions and limitations of § 761.11 do not apply to:
(a) Surface coal mining operations for which a valid permit, issued under Subchapter G of this chapter or an approved State regulatory program, exists when the land comes under the protection of § 761.11. This exception applies only to lands within the permit area as it exists when the land comes under the protection of § 761.11.
(b) With respect to operations subject to Subchapter B of this chapter, lands upon which validly authorized surface coal mining operations exist when the land comes under the protection of 30 U.S.C. 1272(e) or § 761.11.