§ 33.129. Determination and record of air supply.

 (a)  Measurement of air supply. Once each working day or more frequently, if specific conditions indicate the necessity therefore, the mine superintendent, foreman, or other competent person shall measure the quantity of air in circulation in the mine by means of an anemometer or other efficient instrument. Each measurement shall be made at the inlet and outlet airways, and at the crossheading nearest the working areas. During working periods, air measurements shall be made while men are working in the mines. The results of such measurements shall be entered in the mine ventilation report book.

 (b)  Ventilation report book. The superintendent of each mine shall be responsible for insuring that a mine ventilation report book is provided and that the measurements of air required in subsection (a) are taken and recorded in such book. The mine ventilation report book shall always be kept available for inspection by the duly authorized representative of the Department.