Pierre River Mine Project

AIR AENV SIRS 6 – 14
Section 11.1
Request 10b What might the range of new values be if the model was to be re-run, and how
are these estimates are arrived at?
Response 10b As discussed in AENV SIR 10a, the effect of the incorrect location of the Stony
Plain upper air station in the 1995 CALMET data set was negligible; therefore,
the CALPUFF predictions would not be measurably affected.
Request 10c What is the statistical level of confidence that supports the estimated change in
any of the expected outcomes?
Response 10c As discussed in AENV SIR 10a, only a few hours of the 1995 CALMET data set
were affected by the incorrect location of the Stony Plain upper air station. While
it is not possible to determine the statistical confidence, professional judgment
suggests that the CALPUFF predictions would not be measurably affected.
Question No. 11
Request Volume 2, SIR 249, Page 20-40.
In concert with the concerns raised with SIR 247, Shell provides a data
validation of MM5 with two supporting figures. Figure 249-2 in particular
compares the upper air results for a particular sounding in 1995. As can be seen
in this figure, at lower altitudes the MM5 and Fort Smith data are comparable
while the Stony Plain data are different. All three data sources show good
agreement at higher altitudes.
Given the problem with the easting coordinate for Stony Plain in 1995 as
previously noted, any errors in the projected wind field will be more prevalent at
lower altitudes as opposed to the higher levels. Such errors would have a much
greater effect on dispersion of air pollutant emissions at the lower altitudes,
meaning that the concurrence of the data at the higher altitudes is largely
irrelevant.
11a Verify that the displacement of the Stony Plain upper air station does not affect
the rawinsonde data used in the modeling, and as such did not affect the
predicted dispersion modeling results.
Response 11a The displacement of the Stony Plain upper air station does not affect the
rawinsonde data used in the modelling and the CALPUFF predictions would not
be measurably affected.
The effects of the displacement of the Stony Plain upper air station in the 1995
CALMET data set were assessed in AENV SIR 10a. The vertical profiles of
temperature, wind speed and wind direction for the grid cell containing the Pierre
April 2010 Shell Canada Limited 11-11
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