In 2014, the Mine Safety and Health Administration (MSHA) raised the standard for respirable coal dust to 1.5 milligrams per cubic meter (mg/m3) from the 2 mg/m3 standard established in the 1970s. Coal Age readers might recall Assistant Secretary of Labor Joseph Main announcing that 99% of the mining industry had complied with the new rule. Between August 1, 2014, when the new final rule took effect, through December 31, more than 23,600 dust samples were collected and about 99% of them were in compliance. Main was excited about the results.

    In February 2016, MSHA’s respirable dust campaign entered a second phase. The agency required underground coal operators to monitor respirable coal dust with continuous personal dust monitors, or CPDMs. The new devices would be used to provide real-time data on dust concentrations. The logic was straightforward. If the dust was higher than allowable limits, the miners could move to fresh air until the situation was mitigated.

Only one device, the PDM3700, was approved as intrinsically safe (IS) for use underground. An IS approval from MSHA means that the device is permissible for use past the last open crosscut. A permissible device will not create a spark. A spark beyond the last open crosscut, an area which might be gassy, could create an ignition, which in a worst-case scenario would kick up coal dust and create a full blown mine explosion.

On May 7, 2024, Chad Huntley, an MSHA investigatory team lead approached Coal Age with evidence of what he considered to be a cover-up by the agency (see Faulty CPDMs, p. 14). In August 2021, a PDM3700 had caught fire underground at a Warrior Met mine in Alabama. No one knew about this except Warrior Met, the agency and the manufacturer (Thermo Fisher Scientific). My primary concern in publishing this story was to warn the industry of a hazard that could seriously injure miners and potentially cause a catastrophic situation.

While I was writing the story, checking the facts, and vetting the whistleblower, a second unit caught fire underground at undisclosed coal mine and MSHA finally issued a Safety Alert. To the best of my knowledge,
I had never met Huntley before he reached out. He provided documents to Coal Age that he and his representative, Jeff Darby, had obtained through a Freedom of Information Act request. Both MSHA and Thermo were offered a chance to respond to questions and as of press time they had not.