Interim Baseline Radiological Investigation Report
November 14, 2012
Bear Lodge Project, for Rare Element Resources, Ltd.
Rev.1
24
4.4
Surface Soil Ra-226 Estimates Based on Gamma-Soil Radium Correlation
To estimate Ra-226 concentrations corresponding to each of the gamma survey points shown in
Figure 3.3, a gamma-soil radium correlation was established using the surface soil analytical
results documented in Section 4.2 for all random soil sample locations where integrated gamma
measurements were taken (n=23). One-minute integrated direct radiation measurements were
collected at each of these 23 locations, using the same radiation detection equipment used in the
GPS gamma survey. These measurements then were correlated to soil Ra-226 concentrations as
discussed below. Table 4.4 lists the observations.
Table 4.4. Radium-226 Concentrations and Integrated Gamma Count Rates
Sample Location
Radium-226
(pCi/g)
Gamma Count Rate
(cpm)
SS-01-SS-081211
1.2
18,067
SS-02-SS-081211
1.2
21,908
SS-03-SS-081211
1.0
15,552
SS-04-SS-081211
2.0
26,466
SS-05-SS-081211
1.2
18,646
SS-06-SS-081211
1.0
15,868
SS-07-SS-081211
2.5
30,247
SS-08-SS-081211
a
1.5
20,706
SS-10-SS-081211
1.7
20,648
SS-11-SS-081211
1.5
19,619
SS-12-SS-081311
1.3
23,939
SS-13-SS-081311
0.9
18,397
SS-14-SS-081311
0.3
c
9,193
SS-15-SS-081311
1.4
14,803
SS-24-SS-081411
1.4
14,888
SS-25-SS-081311
1.3
29,122
SS-26-SS-081311
1.3
13,785
SS-27-SS-081311
0.3
c
20,031
SS-28-SS-081311
a
0.3
c
14,529
SS-30-SS-081311
0.3
c
17,490
SS-31-SS-081311
1.1
17,954
SS-32-SS-081311
1.7
34,813
SS-33-SS-081311
a
3.3
53,388
SS-35-SS-081311
b
9.8
192,332
Notes:
a
Duplicate sample collected at this location. Ra-226 concentrations average for the calculation.
b
Biased sample not included in the linear regression analysis.
c
Reporting limit of 0.3 pCi/g used, in lieu of the reported result (0.0 pCi/g).
cpm = counts per minute
pCi/g = picocuries per gram
