Interim Baseline Radiological Investigation Report
November 14, 2012
Bear Lodge Project, for Rare Element Resources, Ltd.
Rev.1
45
Table 8.5. Summary Statistics for Lanthanide Concentrations in Air
Lanthanide Concentration (µg/m
3
)
Average
Standard
Deviation
Minimum
Maximum
Location
Ce
La
Ce
La
Ce
La
Ce
La
AMS-01
6.4E-04
3.3E-04
4.0E-04 2.2E-04 3.1E-04 1.5E-04 1.6E-03 8.7E-04
AMS-02
2.6E-03
1.5E-03
6.6E-03 3.8E-03 1.2E-04 5.9E-05 2.0E-02 1.2E-02
AMS-03
4.0E-04
2.0E-04
1.3E-04 6.5E-05 2.3E-04 1.2E-04 6.4E-04 3.4E-04
AMS-04
1.1E-03
5.7E-04
1.1E-03 9.1E-04 2.6E-04 1.4E-04 5.6E-03 2.8E-03
Site-Wide 1.2E-03
6.5E-04
3.4E-03 1.9E-03 1.2E-04 5.9E-05 2.0E-02 1.2E-02
Notes:
Ce = cerium
La = lanthanum
µg/m
3
= micrograms per cubic meter
8.2 Particulate Matter Fractions
RER conducted Particulate Matter 2.5 (PM
2.5
: particles with a nominal diameter less than 2.5
microns) and Particulate Matter 10 (PM
10
: particles with a nominal diameter less than 10
microns) measurements for 24 hours at each of the four AMS locations, to further characterize
particulates in air.
Tables 8.6 and 8.7 list the individual concentrations of the PM
10
and PM
10
filters, respectively.
PM
2.5
and PM
10
concentrations were determined by dividing the laboratory-reported mass by the
volume of air sampled in the 24-hr period. The concentrations are compared to their respective
40 CFR 50 24-hr standards, which are 15 µg/m
3
(PM
2.5
) and 150 µg/m
3
(PM
10
).
For the purpose of reference, the PM
2.5
standard is met when:
•
The annual arithmetic mean concentration (averaged over three years) is less than or
equal to 15 µg/m
3
, or
•
The 98
th
percentile 24-hr concentration is less than or equal to 65 µg/m
3
.
The 98
th
percentile is defined in 40 CFR 50 Appendix N as the daily value out of a year of PM
2.5
monitoring data below which 98 percent of all daily values fall.
The PM
10
standard is met when the expected number of days per calendar year with a 24-hr
average concentration above 150 µg/m
3
is equal to or less than one.
