Section 166(3) in The Coal Mines Regulations, 2011
(3)The covering of every shaft sealed off or covered for ventilation purposes, every fan drift, duct or casing and every part of a mechanical ventilator or fan within such drift, duct or casing, and every air-crossing and ventilation door shall be constructed of fire-proof material:Provided that this regulation shall not apply to the small lid of a shaft-covering operated by the rope cappel.
