Section 148(4) in The Coal Mines Regulations, 2011
(4)Every zone shall be given a distinct number and every section, the code letters a, b or c in a systematic manner and such zones and sections, with their numbers and code-letters, shall be clearly marked on a plan prepared on a scale having a representative factor of not less than 2000: 1 hereinafter called the sampling plan, clearly showing the areas of the mine that are naturally wet throughout.
