Page 228 - Advanced Mine Ventilation
P. 228
208 Advanced Mine Ventilation
Table 12.10 ACGIH Threshold Limit Values for Some In-Mine Dusts [21]
Substance TLVdTWA Comments
Arsenic, elemental 0.01 mg/m 3 Confirmed carcinogen
3 a
Asbestos, amosite (0.5 fiber/cm ) Confirmed carcinogen, applies to fibers >5 m
long
3 a
Asbestos, (2.0 fibers/cm ) Confirmed carcinogen, applies to fibers >5 m
chrysotile long
Asbestos, 0.2 fiber/cm 3 Confirmed carcinogen, applies to fibers >5 m
crocidolite long
3 a
Asbestos, other (2.0 fibers/cm ) Confirmed carcinogen, applies to fibers >5 m
forms long
Calcium carbonate 10 mg/m 3 If no asbestos and <1% silica present
Coal dust, 2 mg/m 3 For coal dust with <5% silica; otherwise silica
respirable limit applies
DPM 0.12 mg/m 3 Only in West Virginia and Pennsylvania (United
States)
Graphite (natural) 2 mg/m 3 All forms except fibers; respirable fraction only
Kaolin, respirable 2 mg/m 3
Magnesite 10 mg/m 3 For total dust with no asbestos and <1% silica
Mica, respirable 3 mg/m 3
Nuisance dusts 10 mg/m 3 For total dust with no asbestos and <1% silica
Oil mist, mineral 5 mg/m 3 Excludes vapor; TLV-STEL is 10 mg/m 3
Perlite 10 mg/m 3 For total dust with no asbestos and 1% silica
Portland cement 10 mg/m 3 For total dust with no asbestos and 1% silica
Silica, crystalline
Cristobalite 0.05 mg/m 3 Respirable fraction
Quartz 0.1 mg/m 3 Respirable fraction
Tridymite 0.05 mg/m 3 Respirable fraction
Soapstone, 3 mg/m 3 With no asbestos and <1% silica
respirable dust
Soapstone, total 6 mg/m 3 With no asbestos and <1% silica
dust
Talc 2 mg/m 3 With no asbestos; otherwise use asbestos values
Welding fumes 5 mg/m 3 Composition of welding fumes varies; may be
subject to other TLVs
ACGIH, American Congress of Governmental Industrial Hygienists; STEL, short-term exposure limit; TLV, threshold limit
value; TWA, time-weighted average.
a 3
Proposed for change to 0.2 fiber/cm .