Section 146(12)(h) in The Coal Mines Regulations, 2011
(h)every device used for the prevention and suppression of dust produced by any machinery, equipment or process as also for the filtering of the exhausted air and every dust respirator shall be inspected once at least in every seven days and shall be thoroughly examined and tested at least once in every month and reports of the results of every such inspection, examination and test shall be recorded in the register kept for the purpose: