(7)(a)At the top of the shaft or at the landing where the bucket or other means of conveyance is normally landed, suitable covering with door shall be provided:Provided that, except as may be required for the passage of the bucket or other means of conveyance, the covering and doors shall always be kept closed.(b)Where the shaft exceeds 45 meters in depth, the persons working at the bottom of the shaft shall also be protected by an adequate protective covering, extending over the whole area of the shaft which shall be provided with a door for the passage of the bucket or other means of conveyance, to be kept lowered to within 22.5 metres of the bottom of the shaft at all times when sinking is in progress:Provided that where special circumstances exist, the Chief Inspector may, by an order in writing and subject to such conditions, as he may specify therein, grant an exemption from the provisions of this clause.
