Interim Baseline Radiological Investigation Report
November 14, 2012
Bear Lodge Project, for Rare Element Resources, Ltd.
Rev.1
51
•
Site-wide, radon concentrations ranged from to 6.0x10
-11
to 1.3x10
-8
and averaged
1.5x10
-9
µCi/ml. Higher concentrations occur in the vicinity of Bull Hill Mine. In terms
of effluent concentrations, some of the measured values exceed the 10 CFR 20 limit of
1.0 x10
-10
µCi/L for radon-222 with daughters present. However, on average the
measured values are within the range of reported worldwide ambient background radon
concentrations, 2.7x10
-11
to 2.7x10
-9
µCi/ml.
•
Particulate radionuclide concentrations in air across the site are consistently low and at
levels at least 92 % below their respective 10 CFR 20 effluent levels.
•
Site-wide cerium and lanthanum particulate concentrations in air are 1.2x10
-3
and 6.5x10
-
4
µg/m
3
, respectively. The range of cerium concentrations is 1.2x10
-4
to 2.0x10
-2
µg/m
3
.
The range of lanthanum concentrations is 5.9x10
-5
to 1.2x10
-2
µg/m
3
.
•
PM
2.5
and PM
10
measurements continue to be collected at the Bear Lodge Project. One
year of data is needed to compare site measurements to applicable standards.
•
Radiological impacts incurred during the development and operation of the mine, if any,
will be determined by comparing the data sets of this baseline and future surveys.
