Inlet and Return Air Passages Separated by Pillar of Stone or Coal

Section 510. Inlet and Return Air Passages Separated by Pillar of Stone or Coal.--The inlet and return air passages for any particular district must be separated by a pillar of coal or stone, if the thickness and dip of the vein will permit, except where it is necessary to cut through said dividing pillar for the purposes of ventilation, traffic or drainage.