§ 33.122. Ventilating current.

 The ventilating current shall be circulated to and along the face of each working place throughout the entire mine in sufficient quantities to dilute, render harmless, and sweep away all smoke or noxious or dangerous gases so that all working places and traveling roads shall be in a safe and fit state in which to work and travel. The minimum quantity of air that is provided shall be not less than 100 cubic feet per minute for each employe in the mine and not less than 200 cubic feet per minute for each animal used underground. The Department, in its opinion, may require as much additional air as individual mine conditions warrant. If at any time it is found that the amount of air required by this subchapter is creating a dangerous roof condition in clay mines, the Department or its authorized representative, may reduce the amount required.