Montana Mineral Conveyance Act - 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.
Requires the Northern Cheyenne Tribe to waive each legal claim relating to the failure of the United States to acquire in trust for the Tribe the private mineral interests underlying the Cheyenne tracts as part of the Tribe's reservation.
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.