225 ILCS 705/31.30
In mines worked by the so-called "enclosed panel system" where rooms are driven off of both sides of the panel entries and ventilated by one side of the panel as the intake airway and the other side as the return, the following shall govern the method of working this type of panel: When the top end or inby end of the panel begins to squeeze, work or more as the result of extraction of coal and the area cannot be examined, men working in the said panel and rooms shall be removed until movement has abated and the presence of gas cannot be detected with a multi-gas detector . However, if in such panels fire, barrier or cutoff pillars are left in the center of the panel of adequate thickness and the entries have been sealed in line with the pillars with adequate roof support on the inby side of the seals isolating the worked out area from the live works, then mining operations may be resumed. This shall not apply to panels worked with rooms on the intake side only, or panels with bleeder entry system whereby the gas released in the squeezed area will not contaminate the ventilating air current used to ventilate active workings within the panel.
225 ILCS 705/31.30