Illinois Statutes Chapter 765. Property § 515/4. Initiation of proceedings

(a) Vested in fee simple with the whole or undivided interest in the surface estate overlying the particular mineral sought to be developed;

(b) Vested in fee simple with an undivided interest in all or part of the particular minerals sought to be developed;

(c) Vested in fee simple with the entire interest in the particular minerals sought to be developed under lands immediately adjacent and contiguous to those lands under which the same minerals are vested in unknown or missing owners; or

(d) Vested with a valid and subsisting mineral lease, the lessor of which is a person defined under either paragraph (b) or (c) of this Section.