National Academies Calls for Improvements in Coal Mine Dust Sampling, Monitoring

Published July 11, 2018

The use of personal coal dust monitors in coal mines should be expanded to obtain accurate information about exposures to respirable coal dust, according to a report released in June by the National Academies of Science, Engineering, and Medicine. The report discusses an MSHA rule issued in 2014 that requires use of a device called a continuous personal dust monitor—a piece of wearable technology that provides real-time measurements of accumulated and full-shift exposures to respirable coal mine dust.

The rule, which went into effect in 2016, requires mine operators to take corrective action whenever a full-shift measurement exceeds the MSHA exposure limit for coal mine dust of 1.5 mg/m3. MSHA later reported that approximately 99 percent of the respirable coal mine dust samples collected during April, May, and June 2016 were in compliance.

But the National Academies report suggests those early results may be misleading. Because the rule requires only a few coal miners to wear a CPDM, monitoring based solely on results obtained from those devices might overlook higher exposures among miners who are not wearing CPDMs. In addition, miners wearing CPDMs receive near real-time feedback on their exposures, and high readings might induce them to alter their work—for example, by moving to a different location. Such changes might result in readings that aren’t representative of the miners with the highest exposures.

The National Academies report calls for NIOSH and MSHA to evaluate exposures to miners who are not wearing CPDMs and to examine the content and implementation of training programs on exposures to respirable coal mine dust. The report also recommends that NIOSH develop a cheaper, lighter version of the CPDM as well as a real-time crystalline silica monitor.

This week, MSHA issued a request for information that would help the agency develop the framework for a retrospective study to assess the health effects of its 2014 rule.