Coal Mining Occupational Health and Safety Regulations (SOR/90-97)

121 (1) Immediately before the beginning of every shift and at least once every day, the barometric pressure and temperature out of doors above ground at a coal mine shall be measured and recorded by a qualified person or by mechanical means.

(2) The mine manager shall, within 24 hours after the making of a record referred to in subsection (1), countersign the record or a copy thereof.