Section 143(13)(d) in The Coal Mines Regulations, 2017
(d)no plant for the screening or sorting of coal and as far as practicable, no heap of cinder, cement, sand, mortar or other dry and fine material shall be placed within 80 meters of the top of down-cast shaft or intake airway nor shall any such material be so handled as to make it air-borne and drawn into such shaft or such airway;