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 .
   223   224   225   226   227   228   229   230   231   232   233