225 ILCS 720/6.03

(a) Liability under the bond shall be for the duration of the mining operations and reclamation, and for a period coincident with the operator's responsibility for revegetation requirements under the permit, this Act and rules under this Act. (b) Liability under the bond for areas used for the disposal of slurry and gob shall continue for the longer of the period specified in subsection (a) or while such areas are in active use.