225 ILCS 720/4.02

Each operator shall adopt measures consistent with known technology in order to prevent subsidence causing material damage to the extent technologically and economically feasible, maximize mine stability, and maintain the value and reasonably foreseeable use of surface lands, except in those instances where the mining technology used requires planned subsidence in a predictable and controlled manner. Nothing in this Section shall be construed to prohibit the standard method of room and pillar mining.