.-There shall be kept at a belowground mine, more than three legible tracings of the working of the mine upto a date not before three preceding months. The tracing shall show the system of ventilation in the mine, and in particular, the general direction of air current, every point where the quantity of air is measured, every air-crossing, ventilation-door stopping, booster fan and any other principal device for regulation and distribution of air, fire-dams, preparatory stoppings, every fire-fighting equipment, every water-dam with dimensions and other particulars of construction, every pumping, telephone and ambulance station, every room used for storing inflammable material, reserve stations and every haulage and travelling roadway. The signs specified in Schedule V shall be used in the said tracings.
