Table 2-14. Respirable coal mine dust: Geometric mean exposures and percent exceeding designated occupational exposure limits by type of mine, MSHA inspector and mine operator samples, 1979–2003
- indicates incalculable field.PEL - permissible exposure limit REL - recommended exposure limit GM - geometric meanmg/m3 - milligrams per cubic meterMRE - Mining research EstablishmentMSHA - Mine Safety and Health Administration
Note: In coal mining, for respirable dust containing less than or equal to 5% quartz, the MSHA PEL is 2 mg/m3 MRE; for respirable dust containing greater than 5% quartz, the MSHA PEL is [(10 mg/m3 MRE) / (% quartz)]. The NIOSH REL of 1 mg/m3 MRE for respirabl
Source: MSHA coal mine inspector and mine operator dust data.
