Mont. Code § 77-2-304
All coal, oil, oil shale, gas, phosphate, sodium, and other mineral deposits in state land, except sand, gravel, building stone, and brick clay, which were not reserved by the United States before July 1, 1927, are reserved to the state. Those deposits are reserved from sale except upon a rental and royalty basis as provided by law. A purchaser of state land acquires no right, title, or interest in or to any of those deposits. The state also reserves for itself and its lessees the right to enter upon state land to prospect for, develop, mine, and remove mineral deposits and to occupy and use so much of the surface of the land as may be required for all purposes reasonably extending to the exploring for, mining, and removal of the deposits from the land, but the lessee shall make just payment to the purchaser for all damage done by reason of entry upon the land and the use and occupancy of the surface of the land.
§ 77-2-304, MCA