43 CFR §3809.334

1. (a)If you stop conducting operations for any period of time, you must—
   1. (1)Maintain public lands within the project area, including structures, in a safe and clean condition;
   2. (2)Take all steps necessary to prevent unnecessary or undue degradation; and
   3. (3)Maintain an adequate financial guarantee.
2. (b)If the period of non-operation is likely to cause unnecessary or undue degradation, BLM, in writing, will—
   1. (1)Require you to take all steps necessary to prevent unnecessary or undue degradation; and
   2. (2)Require you, after an extended period of non-operation for other than seasonal operations, to remove all structures, equipment, and other facilities and reclaim the project area.