Mining Project: Investigating Mining Practices and Respirable Crystalline Silica Exposures in Underground Coal Mines

Research Summary

Coal miners continue to suffer negative health outcomes due to overexposure to respirable coal mine dust. Despite historically high rates of compliance with respirable dust standards, coal mine workers are experiencing increased rates of coal workers’ pneumoconiosis (CWP). Research hypothesizes that these illnesses are due to excessive respirable crystalline silica (RCS) exposure from changes in coal mining practices, especially related to increased rock extraction.

These concerns are reflected in a 2018 publication from the National Academies of Sciences, Engineering, and Medicine (NAS), “Monitoring and Sampling Approaches to Assess Underground Coal Mine Dust Exposures.” The committee recommended that NIOSH conduct a systematic evaluation of trends in coal mining practices “to determine the extent to which those changes [in mining practices] have caused increased extraction of rock and the extent to which past rock extraction has been co-located with disease hot spots.” This research attempted to fill this and other knowledge gaps through evaluations of historic and current Mine Safety and Health Administration (MSHA) and NIOSH records and in-mine surveys of mining practices and associated exposures.

To address these issues, this project had three research aims, which were undertaken as follows:

1. To review historical and current mining conditions and RCS exposure records. This review systematically accessed, aggregated, and analyzed governmental records using existing and new data-sharing/data-use agreements. Sources of data included MSHA compliance data (dust citations), MSHA health inspection reports, and MSHA-approved mine ventilation plans. These data were synthesized into a database to support queries of several potential factors and variables—geological conditions, operating conditions, geographical information, regulatory compliance history, and rates of interstitial lung disease.
2. To investigate potential health links between rock extraction and miner lung disease. Using historic and current coal miner lung disease data from the NIOSH Coal Workers’ Health Surveillance Program (CWHSP), researchers sought to determine the extent to which the factors identified in the first research aim are linked with rates of CWP across the U.S. This task additionally examined the potential role that documented mining practices may have on CWP in mine workers. Using NIOSH-generated surveillance data, this project worked to associate rates of disease in certain demographic and geographic categories to historic and regional work practices.
3. To benchmark current mining conditions and characterize dust exposures in coal mines. Researchers performed a review of ventilation plans and MSHA health inspection reports to establish a baseline of RCS exposures and collect benchmark information about mining conditions, ventilation, and dust control practices. Based on these key factors, mines exhibiting those same or similar characteristics were selected for underground sampling and observation in the future.

This project’s impact could be assessed by the degree to which the findings and recommendations are integrated into future intramural and extramural research activities to reduce associated RCS exposures and the incidence of miner lung disease. This project provided important insights to researchers, MSHA, and mine operators on trends in mining conditions and approaches to reduce associated RCS exposures. Cleaner mine atmospheres will minimize the personal, societal, and economic burdens of miner lung disease.