(225 ILCS 720/4.04) (from Ch. 96 1/2, par. 7904.04)
    Sec. 4.04. Exploratory Holes. All exploratory holes no longer necessary for underground mining shall be filled or sealed, maximizing to the extent technologically and economically feasible return of mine and processing waste, tailings, and any other waste incident to the underground mining operation, to the mine workings or excavations.
(Source: P.A. 81-1015.)