Section 104(5) in The Coal Mines Regulations, 2011
(5)All corners and bends in road shall be made in such a way that the operators and drivers of vehicles have a clear view upto a distance not less than 30 metres along the road.Provided that where it is not possible to ensure visibility upto a distance of not less than 30 metres, there shall be provided two roads for the incoming and outgoing traffic or an alternative system:Provided further that adoption of an alternative system shall be intimated to the Regional Inspector in writing.