; and (ii) identifying any limitations or impediments for such use in underground coal mines. (B) Authority If the Secretary determines that such direct reading monitor is sufficiently reliable and accurate for the enforcement of mandatory health and safety standards under this Act following such report or any update thereto, the Secretary shall promulgate a final rule authorizing the use of such direct reading monitor for purposes of compliance and enforcement, in addition to other methods for determining total incombustible content. Such rule shall specify mandatory operator sampling locations, methods, and intervals. . (b) Rock dust recordkeeping Section 304 is further amended— (1) by redesignating subsection (e) as subsection (f) and inserting after subsection (d) the following: (e) Rock dust recordkeeping Each coal mine shall be required to maintain and continuously update a record of the amount of rock dust purchased. ; and (2) in subsection (f) (as so redesignated), by striking Subsection (b) through (d) and inserting Subsections (b) through (e) . 503. Atmospheric monitoring systems Section 317 ( 30 U.S.C. 877 ) is amended by adding at the end the following: (u) Atmospheric monitoring systems (1) Regulations required Not later than 1 year after the date of enactment of the Robert C. Byrd Mine Safety Protection Act of 2017 , the Secretary shall, following consultation with the National Institute for Occupational Safety and Health, promulgate regulations requiring that each operator of an underground coal mine install atmospheric monitoring systems that— (A) protect miners where the miners normally work and travel; (B) will assist in mine emergency response and the conduct of accident investigations; (C) provide real-time information regarding methane, oxygen, and carbon monoxide levels, and airflow direction, as appropriate, with sensing, annunciating, and recording capabilities