Pennsylvania Statutes Title 52 P.S. Mines and Mining § 70-521. Quantities of air measured weekly with anemometer by mine foreman recorded in report book; report of measurement sent to inspectors before twelfth of the month for preceding month

The quantities of air in circulation shall be ascertained with an anemometer or other efficient instrument; such measurements shall be made by the inside foreman or his assistant once every week at the intake and return airways, also at or near the face of each gangway and at the nearest crosscut to the face of the inside and outside chamber or breast where men are employed. The quantities of air in circulation shall be entered in the colliery report book. A report of these air measurements shall be sent to the inspector before the twelfth day of each month, for the preceding month, together with a statement of the number of persons employed in each district.