Paragraph 9
The manager of every mine shall make and secure the efficient carrying out of arrangements whereby the quantity of air passing each of the points hereinafter mentioned is measured at intervals not exceeding thirty days.
The points at which such measurements are to be taken are—
in every intake airway starting at an entrance to a shaft or outlet, a point as near as is practicable to that entrance;
in every split by which air leaves an air current except a split at a longwall face, a point as near as is practicable to the junction;
in any part of the mine in which determinations of firedamp content are required to be made, the points at which those determinations are made, excluding any point at which determinations are made because it has been specified in a notice served on the manager by an inspector; and
in any part of the mine containing a working face, being a part in which determinations of firedamp content are not required to be made under these regulations, a point in each road, which as regards a working face is an intake airway and the air in which has not previously ventilated a working face, as nearly as practicable four hundred and fifty feet from the nearest part of the said working face with respect to which that road is an intake airway, unless that point would be within three hundred feet of a point at which measurements are taken under sub-paragraph (a) or (b).
A measurement of the quantity of air at a point specified in sub-paragraph (c) of the last preceding paragraph shall be taken on an occasion when a determination of firedamp content is made thereat.
Notwithstanding anything in paragraph (1) of this regulation, whenever any alteration is made in the arrangements for ventilating a mine which affects or may affect substantially the quantity of air passing any point at which measurements thereof have to be taken, a measurement of the quantity at each such point shall be taken as soon as any substantial effect of the alteration would be apparent.
Particulars of every measurement taken in accordance with this regulation shall be recorded forthwith in a book provided for the purpose by the owner of the mine together with any other information incidental thereto for which provision is made in that book.