Interim Baseline Radiological Investigation Report
November 14, 2012
Bear Lodge Project, for Rare Element Resources, Ltd.
Rev.1
27
5.0
DATA QUALITY ASSESSMENT FOR SOIL
This section briefly summarizes the results of the quality control (QC) samples collected for the
baseline soil sampling program. As indicated in Table 4.2, 10 percent of the soil samples
collected was duplicated for QC purposes. The results of this QC effort are documented in Table
5.1, which lists the analytical results for each duplicate pair along with corresponding errors and
reporting limits (RLs). Table 5.2 documents associated comparisons, presenting the
corresponding Replicate Error Ratio (RER) or Relative Percent Difference (RPD), in the case of
U-nat) for each QC pair. These tables are provided at the end of this section.
Examination of the results provided in Table 5.1 indicates that, in general, there is close
agreement in the analytical results reported for each duplicate pair collected for all parameters.
An apparent anomalous result was reported for Ra-228 for one sample pair (SS-08-SS-081211
and SS-09-SS-081211); the results are highlighted in Table 5.1. Because duplicate results are
generally comparable for the majority of QC samples collected and the other parameters for this
pair of soil samples were within acceptable ranges, no request to re-analyze the samples were
made.
Table 5.2 presents the corresponding RER and, in the case of U-nat, RPDs calculated for each
duplicate pair. The calculation of RER and RPDs is a standard technique used to evaluate QC
samples. Typically, an RER of < 2 and an RPD of <20 percent is used as a guideline in many
data quality objective evaluations. This data set shows two cases (highlighted in Table 5.2)
where either the RER or RPD was greater than 2 and 20, respectively. Considering the low levels
of radioactivity observed in most of the QC pairs, the laboratory performance on blind duplicates
is satisfactory.
