43 CFR §3207.14

1. (a)BLM will extend your lease for 5 years under a drilling extension if at the end of the 10th year or any subsequent year of the initial or additional extension of the primary term you:
   1. (1)Have not met the requirements that you must satisfy for BLM to grant or to continue the initial or additional extensions of your primary lease term under § 3207.12, or your lease is in its 20th year;
   2. (2)Commenced drilling a well before the end of such year for the purposes of testing or producing a geothermal reservoir; and
   3. (3)Are diligently drilling to a target that BLM determines is adequate, based on the local geology and type of development you propose.
2. (b)The drilling extension is effective on the first day following the expiration or termination of the primary term.
3. (c)At the end of your drilling extension, your lease will expire unless you qualify for a production extension under § 3207.15.