Section 179(4) in The Coal Mines Regulations, 2011
(4)Where electric lighting is used, an addition light or lamp having no connection with electric supply shall be kept continuously burning -(i)belowground, in every shaft bottom or landing in regular, use and in every engine room;(ii)on the surface, after dark, at the top of every working shaft and in every engine room; and(iii)in travelling roadway and escape routes.