Code of Federal Regulations Title 43. Public Lands:  Interior § 43.3802.1–1 When required

(a) Any mining operations which involve construction of means of access, including bridges, landing areas for aircraft, or improving or maintaining such access facilities in a way that alters the alignment, width, gradient size, or character of such facilities;

(b) Any mining operations which destroy trees 2 or more inches in diameter at the base;

(c) Mining operations using tracked vehicles or mechanized earth moving equipment, such as bulldozers or backhoes;

(d) Any operations using motorized vehicles over other than open use areas and trails as defined in subpart 6292 of this title, off-road vehicles, unless the use of a motorized vehicle can be covered by a temporary use permit issued under part 2930 of this chapter;

(e) The construction or placing of any mobile, portable or fixed structure on public land for more than 30 days;

(f) On mining operations requiring the use of explosives;  or

(g) Any operation which may cause changes in a water course.