The secretary has the power to grant concessions in [the] state parks and recreation areas upon such rentals, fees or percentage of income or profits as he may prescribe, but not for a longer period than thirty years. All concessions shall be evidenced by a written contract, the faithful performance of which shall be secured by such bond as the secretary may prescribe. No contract granting a concession shall be effective until it has been approved by the state board of finance.
NMS § 16-2-9