All portals, entryways, drifts, shafts, or other openings between the surface and underground mine working shall be sealed when no longer needed for the conduct of the underground mining operations.
225 ILCS 720/4.03
Sealing Openings
P.A. 81-1015.
Official source: Illinois General Assembly. Reproduced from public-domain Illinois statutes; confirm against the official source for the current text. Not legal advice.