Interim Baseline Radiological Investigation Report
November 14, 2012
Bear Lodge Project, for Rare Element Resources, Ltd.
Rev.1
49
The exposure rates determined above are similar to average worldwide exposures to natural
radiation sources comprised of cosmic radiation, cosmogenic radionuclides, and external
terrestrial radiation reported in the United Nations Scientific Committee on the Effects of Atomic
Radiation (UNSCEAR) Report to the General Assembly, Sources and Effects of Ionizing
Radiation, Annex B (UNSCEAR, 2006). The typical ranges of average worldwide exposures
reported in this reference document are to 60 to160 mrem/yr. With the exception of AMS-02, all
other AMS locations are within or near the upper range estimate of 160 mrem/yr. AMS-02 is
significantly higher than the remaining AMS locations but agrees well with the estimated gamma
exposure rate near 50 μR/hr observed in the gamma survey of the property (Figure 3.3). It is
likely that the relatively high exposure rate at AMS-02 is from naturally occurring radioactive
materials associated with a rare earth element mineralization.
Appendix F presents the laboratory analytical reports for ambient gamma exposure rates.
