WASHINGTON, July 29 -- The U.S. Department of Labor Mine Safety and Health Administration has issued a notice, published in the Federal Register on July 26, 2023 entitled "Lowering Miners' Exposure to Respirable Crystalline Silica and Improving Respiratory Protection." The notice was issued by Assistant Secretary Christopher J. Williamson. COMMENT DEADLINE: August 28, 2023 * * * SUMMARY: The Mine Safety and Health Administration (MSHA) will hold three public hearings on the proposed rule, L  more