225 ILCS 730/2
The Department of Natural Resources shall notify the permittee, at the time a permit is issued, either to collect or not to collect for the Geological Survey, drill cuttings representing each 5 feet of the distance drilled in cable tool wells and each 10 feet of the distance drilled in rotary wells based upon information supplied by the Geological Survey. Information as to the approved method of collecting drill cuttings shall be obtained from the Geological Survey by the person or persons responsible for the drilling of the well.
Intervals for which drill cuttings are required may be core drilled, in which case representative samples of the core as determined by the Geological Survey shall be submitted to the Geological Survey in lieu of drill cuttings. Cores of intervals for which drill cuttings are not required, and which are not submitted to the Geological Survey, shall be available, in their entirety, as recovered, to authorized representatives of the Geological Survey for inspection and sampling; provided that the sampling shall not involve the removal of any complete section of the core unless complete removal is authorized by the permittee.
225 ILCS 730/2