Effectiveness of the CPDM in Reducing Overexposures to Coal Mine Dust

Abstract

The Mine Safety and Health Administration (MSHA) promulgated a rule in 2014 that required numerous changes in compliance dust sampling requirements for coal mine operators. Two key parts of this rule were the lowering of the respirable coal mine dust standard from 2.0 mg/m³ to 1.5 mg/m³ and requiring operators of underground coal mines to use a continuous personal dust monitor (CPDM) for compliance sampling. The CPDM currently approved for compliance sampling is equipped with a display that provides miners with in-shift information on their respirable dust exposure. The goal is to provide an indication of a potential overexposure and empower the miner and mine operator to implement changes in controls and/or operating practices to prevent an overexposure from occurring. Compliance sampling data for four occupations that have historically had elevated dust exposures were downloaded from the MSHA website and analyzed to assess the impact of the CPDM on overexposures. These occupations include continuous miner operator, roof bolter operator, tailgate-side shearer operator, and jacksetter. MSHA inspector and mine operator sampling data from five years before the rule became effective was compared to sampling results for five years after the dust standard was lowered and CPDM use was required. The analysis indicates that use of the CPDM has resulted in substantially lower percentages of samples exceeding the applicable respirable dust standard for these four occupations. A discussion of key dust rule changes, the CPDM, and compliance sampling results are provided.