77 Ill. Adm. Code 920.ILLUSTRATION A
A Unconsolidated Formations: Oversized Drill Hole
Section 920.ILLUSTRATION AÂ Â Unconsolidated
Formations:Â Oversized Drill Hole
1. Diameter of drill hole must be 3" larger than the outer
diameter of the casing or coupling, whichever is greater.
2. Casing must extend a minimum of 20'.
3. Annular space that exists between hole and casing must be filled
with bentonite grout or neat cement grout within a maximum of 10 feet of the
top of the screen to finished ground surface.
.