Pierre River Mine Project

WATER AENV SIRS 15 – 43
Section 12.1
Response 33c The data to support the position presented in the May 2009 Pierre River Mine,
Supplemental Information, Volume 2, SIR 306b, that the sinkholes do not
exacerbate or attenuate effects of the project, were described in SIR 306a. These
data included:
Reference
• local geology and hydrogeology (Section 5.4.3 and Figures 29, 32 to 38 of
the Hydrogeology ESR, WorleyParsons Komex, 2007)
• groundwater levels in shallow and deeper Quaternary deposits (Figures 37
and 38; WorleyParsons Komex, 2007)
• bathymetry data for Sinkhole Lakes 1 and 2 (EIA, Section 8.4.5.2, pp 8-77)
• water chemistry for Sinkhole Lakes 1 and 2
• groundwater chemistry for Quaternary deposits, McMurray Formation, Basal
aquifer and Devonian Formation (Table 11, WorleyParsons Komex, 2007)
• major ion characterization for Sinkhole Lake, Basal aquifer and Devonian
Formation waters (Figure 306-1, May 2009 Pierre River Mine, Supplemental
Information, Volume 2)
Based on these data, the following conclusions were reached:
• the shallow groundwater flow direction is not altered by the sinkholes
• the hydrochemical signature of the sinkhole lakes is calcium-bicarbonate
(Ca-HCO3) type, indicative of freshwater
• the hydrochemical signature of the basal aquifer near the sinkholes is
sodium-bicarbonate-chloride (Na- HCO3-Cl) type, indicative of an older,
deeper, regional groundwater flow system
• the difference in hydrochemical signatures indicates a lack of hydraulic
connection between the sinkholes and deeper deposits
WorleyParsons Komex. 2007. Hydrogeology Environmental Setting Report for
the Jackpine Mine Expansion and Pierre River Mine Project. Prepared
for Shell Canada Limited, Calgary, AB. Submitted December 2007.
Request 33d In Shell’s discussion of Karst, a reference is made to Figure 8.4-6 in Volume 5 of
the EIA, the Terrestrial Section. Figure 8.4-6 illustrates the locations of three
sinkholes, while Figure 8.4-7 shows there to be four. Clarify this discrepancy.
Response 33d Figure 8.4-7 is based on the surficial geology map by Bayrock (1971) and shows
four sinkhole locations near the border of the Eymundson ESA and a fifth
12-48 Shell Canada Limited April 2010
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