43 CFR § 3483.6
Special logical mining unit rules
June 11, 2020
(a) Production anywhere within the LMU, of either Federal or non-Federal recoverable coal reserves or a combination thereof, shall be applied toward satisfaction of the requirements of the rules of this part for achievement of diligent development and continued operation for the LMU.
(b) The dates for submission of a resource recovery and protection plan and achievement of diligent development shall not be changed by any enlargement or diminution of the LMU.