25 CFR 225.20: Authority to contract.

(a) Any Indian tribe, subject to the approval of the Secretary and any limitation or provision contained in its constitution or charter, may enter into a minerals agreement with respect to mineral resources in which the tribe owns a beneficial or restricted interest.

(b) Any individual Indian owning a beneficial or restricted interest in mineral resources may include those resources in a tribal minerals agreement subject to the concurrence of the parties and a finding by the Secretary that inclusion of the resources is in the best interest of the individual Indian mineral owner.