F1a: Silica in Mining New Standard and Sampling Issues

Ernest N. Morial New Orleans Convention Center 

The Mine Safety and Health Administration (MSHA) finalized a rule to enhance protections for miners against respirable crystalline silica, a known health hazard linked to severe illnesses. The rule, titled "Lowering Miners' Exposure to Respirable Crystalline Silica and Improving Respiratory Protection," updates outdated standards to align with current occupational health practices and the OSHA requirements for General Industry and Construction. The MSHA silica rule introduces a uniform permissible exposure limit (PEL) of 50 micrograms per cubic meter (µg/m³) for an 8-hour time-weighted average across all mining sectors, replacing varied limits based on mine type. An action level of 25 µg/m³ triggers additional monitoring. Operators must implement feasible engineering controls, supplemented by administrative controls, to maintain exposures below the PEL or provide miners with respiratory protection if that is infeasible. The rule addresses a critical health issue, as silica exposure contributes to a 400% increase in lung transplants for black lung disease since 2016, with 1 in 5 Appalachian miners affected.

This study discusses the sampling issues with methods that provide an acceptable ISO compliant respirable sample, appropriate choice of sampling train, the affects of humidity and the interference of other materials not covered by the standard in the ore body. We will also cover some logistical issues with mining overloading analytic labs to comply with the standard.

K. Bosch, Stantec Consulting, Minneapolis, MN, USA, A. Birkbeck, Stantec Consulting, Denver, CO, USA, Scott Maxey, Stantec Consulting , Denver, CO, USA 

None 

Aerosol and airborne particulate monitoring

Exposure Assessment

Regulatory compliance

Respiratory protection