Mining Contract: Respirable Crystalline Silica Characteristics and Sources in U.S. Underground Coal Mines

Contract Status & Impact

This contract is complete. To receive a copy of the final report, send a request to mining@cdc.gov.

Respirable crystalline silica (RCS), which generally occurs as quartz in coal mines, has long been recognized as an occupational health hazard. For decades, the mass content of quartz in respirable dust has been measured in U.S. mines as a means of monitoring RCS exposures. However, a recent surge of severe and rapidly progressive disease linked to RCS suggests that conventional monitoring might not yield sufficient understanding of health risks. In turn, conventional dust control strategies might not be effectively focused. A better understanding of the relative toxicity and contribution of RCS from specific dust sources is urgently needed.

This research seeks to address this need by investigating toxicity-relevant RCS characteristics (particle size and surface characteristics) in real coal mine dust samples and in samples representative of major dust sources (i.e., mined coal and rock strata, and rock dusting products). This project is directly related to Recommendation 9 in the 2018 National Academies Study Report on “Monitoring and Sampling Approaches to Assess Underground Coal Mine Dust Exposures.”

Researchers will characterize the particle size distribution and presence or absence of particle surface occlusion in RCS from real coal mine dust samples and will evaluate major source contributions by comparison of these characteristics between mine dust and source-dust samples. The primary outcome of this work is expected to be a more complete understanding of where and how toxicity-relevant RCS characteristics occur and vary within and between various mine environments.