Mont. Code Ann. § 50-73-205

The original or true copies of all maps must be kept in the office at the mine, and true copies must also be furnished to the department upon request. The maps delivered to the department become the property of the state. The maps must be kept at the office of the department and are open to inspection by all persons interested in them. An examination may only be made in the presence of a department inspector, and the inspector may not permit any copies of the maps to be made without the written consent of the operator or owner of the property, under penalty of removal from office.