Montana Mineral Conveyance Act - (Sec. 4) Requires the Secretary of the Interior, if Great Northern Properties Limited Partnership (the Great Northern Properties) conveys to the Northern Cheyenne Indian Tribe all its mineral interests underlying specified aggregate tracts of land in Montana within the Tribe's reservation (the Cheyenne tracts), to convey to Great Northern Properties all interest of the United States in and to the coal underlying specified unleased federal tracts in Montana outside of the Tribe's reservation.
Prohibits the mineral interests underlying the Cheyenne tracts conveyed to the Tribe from being subject to taxation by the state of Montana.
(Sec. 5) Requires the Northern Cheyenne Tribe to waive all legal claims arising from the continuing failure of the United States to acquire for the Tribe the mineral rights underlying the Cheyenne tracts as part
Instructs the Northern Cheyenne Tribe and Great Northern Properties to jointly notify the Secretary in writing when they have agreed on a formula for the sharing of revenue from the coal produced from the federal tracts. Requires, after such condition is satisfied and within 90 days of the Secretary receiving such written notification, the completion of the mineral conveyances under this Act in a single transaction.
Allows the Secretary or Great Northern Properties, if any part of such conveyances is invalidated by a federal district court and the court's judgment is not vacated or reversed on appeal, to rescind each such conveyance. Requires, if such a rescission is carried out, the Tribe's waiver to be considered as being rescinded.
(Sec. 6) Specifies this Act's effect on the eligibility of the Tribe or its members to receive other federal benefits or services.