; and (ii) identifying any limitations or impediments for such use in underground coal mines. (B) Authority If the Secretary determines, following a report under subparagraph (A) (or an update to such report), that any direct reading monitor described in paragraph (2)(B) is sufficiently reliable and accurate for the enforcement of mandatory health or safety standards under this Act, the Secretary shall, after the submission of such report or update, promulgate a final rule authorizing the use of such direct reading monitor for purposes of compliance with, and enforcement of, such standards and authorizing the use of other methods for determining total incombustible content. Such final rule shall specify mandatory operator sampling locations, methods, and intervals. . (b) Rock dust recordkeeping Section 304 ( 30 U.S.C. 864 ) is further amended— (1) by redesignating subsection (e) as subsection (f); (2) by inserting after subsection (d) the following: (e) Rock dust recordkeeping The operator of each coal mine shall maintain and continuously update a record of the amount of rock dust purchased for each such mine. ; and (3) in subsection (f), as so redesignated, by striking Subsections (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) General regulations 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 Director of 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) assist in mine emergency response and the conduct of accident investigations