Paragraph 26

Two or more auxiliary fans shall not be installed in any section of narrow or panel workings so as to draw air from the same air current unless there is kept at the mine an accurate plan showing the general system of ventilation in that section and the quantity of air in each air current therein.

Upon the preparation of such a plan the manager of the mine shall send a copy thereof to the inspector for the district, and if any change in the system of ventilation or any substantial variation in the quantity of air in any air current thus shown is made, the manager shall send an amended plan or otherwise give notice of the change or variation to that inspector as soon as the effect thereof can be ascertained.