50 C.F.R. § 37.24
Each approved exploration plan shall be supplemented by a written plan of operation for each fiscal year, or portions thereof, covered by the exploration plan. Each plan of operation shall specify the field operations for implementing that exploration plan during the year, or portions thereof, covered by the plan of operation. Each plan of operation shall be submitted to the Regional Director at least 30 days before field operations are to be commenced thereunder, except that any plan of operation supplementing a portion of an exploration plan that received expedited review and approval pursuant to § 37.21(c) shall be submitted 10 days before field operations are to be commenced thereunder. A plan of operation shall set forth such specific information as is required by the Regional Director in determining whether the plan is consistent with the exploration plan to which it pertains and with this part. The permittee shall make such modifications in its plan of operation as are deemed at any time by the Regional Director to be necessary and appropriate to ensure such consistency. Reconsideration of the Regional Director's actions under this section may be obtained by employing the procedures described in § 37.22(c) .
50 C.F.R. §37.24