Colo. Rev. Stat. § 36-1-140
Location of mineral claims, other than claims for coal and oil shale, may be made upon unleased mineral lands belonging to the state. The discoverer of a body of mineral in either a lead, lode, ledge, deposit, vein, or contact shall immediately post conspicuously a notice declaring that he has made such a discovery on the date attached to the notice. Within ten days after posting said notice, the discoverer must notify the state board of land commissioners of said discovery and arrange for a permit to explore the extent of the discovery. Within sixty days from date of discovery, the locator shall be required to take a lease upon such terms as may be agreed upon by the state board of land commissioners or apply for an extension of the permit.
C.R.S. § 36-1-140
For lode claims, see article 43 of title 34 .