The report outlined the results from PDM testing undertaken during the spring and summer of 2003. The introduction of a Mine Safety and Health Administration (MSHA) dust rule had been postponed pending results of this testing.

The PDM is a respirable dust sampler and a gravimetric analysis instrument that is part of a belt-worn mine cap lamp battery. It was developed by NIOSH and Rupprecht & Patashnick (R&P) to measure respirable coal dust to give accurate exposure data at the end of a work shift and show near-real-time dust exposure levels during the shift.

“Laboratory results with different coal types and size distributions showed that there is a 95% confidence that the individual PDM measurements were within ±25% of the reference measurements,” the NIOSH report stated.

“Mine test results indicate that data taken with adjacent PDM and reference samplers are

indistinguishable. The technology proved durable enough to successfully measure 108

shifts of data out of 115 attempts in the mines.

“Under these specific test conditions the PDM demonstrated that it was convenient to wear, robust, provided accurate data, provide timely data that could be used to prevent overexposure, and was easy to use,” NIOSH said.

Initially four Rupprecht & Patashnick (R&P) PDM dust monitors were made available for laboratory evaluation and two additional units were provided for the in-mine

testing.

Six PDM units were then made available for mine testing at mines in Pennsylvania's Pittsburgh seam, Central Appalachian's Eagle coal seam, Central Utah's Hiawatha seam, and Alabama's Blue Creek and Mary Lee seams.

During mine testing NIOSH found the real-time data resulted in quicker recognition of the failure of engineering dust controls, enabling both miners and management to prevent overexposure to coal mine dust. The information also demonstrated how actions and equipment effect a miner’s dust exposure.

“Miners can quickly learn how to better reduce their dust exposures by minimizing certain actions and by better positioning themselves during given activities,” NIOSH said.

R&P business development director Erich Rupprecht said the delivery of the first 25 R&P commercial PDMs to NIOSH and MSHA was slated to take place in the coming months.

These PDM’s will be used for a more-extensive underground mine testing phase that is set to begin in the third quarter of 2004. NIOSH, MSHA, and stakeholders from labor and industry have been convening to develop the testing protocol for this next round of testing.

The full NIOSH report “Performance of a New Personal Respirable Dust Monitor for Mine Use” is available at http://www.cdc.gov/niosh/mining/ under the heading “Mining Spotlights”