43 C.F.R. § 3250.13

BLM may issue the following types of orders or instructions:

(a) Geothermal resource operational orders that contain detailed requirements of nationwide applicability;

(b) Notices to lessees that contain detailed requirements on a statewide or regional basis;

(c) Other orders and instructions specific to a field or area;

(d) Conditions of approval contained in an approved Notice of Intent; and

(e) Verbal orders that BLM will confirm in writing.