43 CFR 3832.33 - How do I locate a mill site?
(a) You may locate a mill site in the same manner as a lode or placer mining claim, except that -
(1) It must be on land that is not mineral-in-character; and
(2) You must use or occupy each two and a half acre portion of a mill site in order for that portion of the mill site to be valid.
(b) If the United States does not own the surface estate of a particular parcel of land, you may not locate a mill site on that land under the General Mining Law or the Stockraising Homestead Act (see part 3838 of this chapter).