The rule would establish approval criteria for new continuous personal dust monitor (CPDM) technology, which would report dust levels in real time throughout a shift.

It would also update the application requirements for existing coal mine dust personal sampler units (CMDPSU) to reflect the technology’s improvements in the past 15 years.

The US Mine Safety and Health Administration and the National Institute for Occupational Safety and Health have put the rule together.

“Existing 30 CFR part 74 specifies requirements by which MSHA and NIOSH jointly approve the design, construction, performance, and manufacturing quality of the CMDPSU.

“These regulatory requirements, which were issued in 1972, are design-specific and do not permit the approval of any other sampling device of a different design,” the two groups said.

The CMDPSU is currently the only permitted design.

“MSHA and NIOSH recognize that the ability to directly measure in real time the amount of respirable coal mine dust to which a miner is exposed offers the best solution for protecting miners from disabling occupational lung disease,” it added.

MSHA and NIOSH officials said the rulemaking was limited only to the requirements for the approval of units, not to how sampling products should be used to be deemed compliant.

Among the proposed rule sections:

Section 74.7(d) – Regarding dust concentration ranges, it would require that the CPDM provide accurate measurements of respirable coal mine dust concentrations for an end-of-shift average measurement within the range of 10% to two times the permissible exposure limit (PEL) for respirable coal mine dust;

Section 74.7(f) – Regarding 74.7(f)(2) on electromagnetic interference, it would require that the CPDM meet standards for the control of, and protection from, electromagnetic interference established by the American National Standards Institute (ANSI), the Federal Communications Commission (FCC), and the International Electrotechnical Commission (IEC);

Section 74.7(h) – Regarding 74.7(h)(1) and (2) on the reporting of monitoring results, it would require adequate legibility or audibility of monitoring results; computer recording of results in a form compatible with widely available computer technology; and reporting of results as cumulative mass concentration in units of mass per volume of air, such as milligrams per cubic meter (mg/m3);

Section 74.7(i) – Regarding power requirements, it would require that the power source for the CPDM has sufficient capacity to enable continuous sampling for 12 hours in a coal mine dust atmosphere of two times the PEL and that a CPDM powered by a rechargeable battery must be recharged using the standard power supplies in mines (110 VAC);

Section 74.7(m) – Regarding tampering safeguards or indicators, it would specify performance requirements that would help assure that CPDMs are designed to prevent intentional tampering and limit inadvertent altering of monitoring results, and that CPDMs have a safeguard or indicator that either prevents altering the measuring or reporting function of the device or indicates if these functions have been altered; and

Section 74.10(a) – Regarding operating instructions and maintenance and service life plan, the section is new and would require the manufacturer to include operating instructions and a maintenance and service life plan with each new CPDM sold.

The mining community may submit comments on the proposed rules until midnight EDST on August 14 via MSHA’s Federal e-Rulemaking Portal, e-mail, fax, regular mail or hand delivery.

MSHA and NIOSH will also host a public hearing on the matter on July 8, from 9am local time, at the agency’s main office in Arlington, Virginia.

Parties wishing to speak at the event are asked to submit a request at least five days in advance of the meeting. If time allows, same-day requests will be accommodated.

The transcript of the meeting, along with all comments and data, will be made available to the public on the MSHA website.