43 C.F.R. § 3270.12

BLM may issue:

(a) Geothermal resource operational orders, for detailed requirements that apply nationwide;

(b) Notices to lessees, for detailed requirements on a statewide or regional basis;

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

(d) Permit conditions of approval; and

(e) Oral orders, which BLM will confirm in writing.