225 ILCS 705/6.06

He shall see that the air current is traveling in its proper course and in proper quantity; and measure with an anemometer the amount of air passing in the last cross-cut or break-through of each pair of entries, or in the last room of each division in long-wall mines, and at all other points where he may deem it necessary; and note the result of such measurements in the mine examiner's book kept for that purpose.