Interim Baseline Radiological Investigation Report
November 14, 2012
Bear Lodge Project, for Rare Element Resources, Ltd.
Rev.1
35
8.0
AIRBORNE PARTICULATES
RER collected samples of airborne particulates at four locations (AMS-01 through AMS04)
using high volume air samplers. The samplers were operated at various intervals, depending on
the parameter of interest and field or sampler conditions. The samples were analyzed for total
particulates (long-lived radionuclides and lanthanides) and particle size fractions.
8.1 Total Particulates
The samplers were used periodically, from November 2011 to July 2012 to collect total
particulates. The locations of the air samplers are shown on Figure 7.1.
Each high volume air sampler was equipped with an 8-in. by 10-in. 0.8 micron glass fiber filter
paper. The air filters were collected at various intervals, prior to saturation. Sample collection
periods lasted from 5 to 40 days, averaging 22 days. Flow rate and total flow data were recorded
at the time of sample collection.
The filters were sent to and digested by the external analytical laboratory. The samples were
analyzed for cerium, lanthanum; natural thorium and uranium, thorium-230, and radium-226
using EPA Methods 200.8 (cerium, lanthanum, natural thorium and uranium), 908.0 (thorium-
230) and 903.0 (radium-226).
The laboratory data were reported in units of picocuries per filter (pCi/f) or micrograms per filter
(µg/f, for natural thorium and uranium; cerium, and lanthanum), as listed in Tables 8-1
(radionuclides) and 8.4 (lanthanides). The data were converted to units of micocuries per
milliliter (µCi/ml), as follows:
) 101(
/
,
12
−
=
x
Flow Total
ion
Concentrat
Filter
ml
Ci
ion
Concentrat
µ
The units of total flow and filter concentration in the equation are cubic meters (m
3
) and pCi/f,
respectively. The laboratory-reported concentrations of natural thorium and uranium were
converted to pCi/g by multiplying the value in µg/f by their respective specific activities
(2.22x10
-7
and 6.77x10
-7
Ci/g, respectively) and 1x10
6
.
Airborne concentrations of cerium and lanthanum were determined by dividing the laboratory
reported concentration (in µg/f) by the volume of air sampled (in standard cubic meters).
Appendix E presents the laboratory analytical reports for particulates.
