Oregon Revised Statutes Public Lands § 275.294

(1) Nothing contained in this chapter shall prohibit the governing body of a county, whenever it appears to the best interest of the county, from making or executing a lease or conveyance granting rights to explore or prospect for valuable minerals or oil and gas and for the mining and removal of the same from any lands acquired by such county through foreclosure of tax liens or otherwise.

(2) Except as provided in subsection (3) of this section, any lease or conveyance of minerals or oil and gas or interest in such lands shall be granted to the highest bidder, after an opportunity for competitive bidding is given by advertisement of the proposed sale or lease for not less than once a week for two successive weeks by publication in one or more newspapers having general circulation in the county, and under such terms, conditions and regulations as the governing body of the county provides under ORS 275.300.

(3) The governing body of the county, as to any land which is owned by the county or whereon the mineral rights are reserved by the county, may execute leases and contracts, other than for gas or oil, upon a royalty basis without requiring bids for the mining of gold, silver, copper, lead, cinnabar and valuable minerals or mineral materials from such lands upon terms and conditions agreed upon by the governing body of the county and the lessee.