30 U.S.C. § 43 : US Code - Section 43: Conditions of sale by local legislature

Search 30 U.S.C. § 43 : US Code - Section 43: Conditions of sale by local legislature

As a condition of sale, in the absence of necessary legislation
by Congress, the local legislature of any State or Territory may
provide rules for working mines, involving easements, drainage, and
other necessary means to their complete development; and those
conditions shall be fully expressed in the patent.