Pierre River Mine Project

WATER ERCB SIRS 46 – 79
References
Question No. 79
Section 7.1
Therefore, a hydraulic conductivity value of 1 x 10 -6 m/s was assigned to the
fluid cells.
The overburden cap hydraulic conductivity (1 x 10 -7 m/s) listed by Shell (2002;
2005) is similar to the value (5 x 10 -7 m/s) listed in EIA, Volume 4B, Appendix
4-1, Table 8, which was adjusted to reflect an average hydraulic conductivity
value for overburden materials local to the Pierre River Mine area.
EIA, Volume 4B, Appendix 4-1, Section 1.2.4.7, indicates that extensive
prediction confidence simulations were conducted for the Pierre River Mine local
model by varying the hydraulic conductivity values of mine pit backfill, fluid
tailings and overburden capping by factors of 10 from calibrated values. This
factor of 10 addresses the uncertainty in the expected properties of these
engineered materials.
Shell (Shell Canada Limited). 2002. Application for Approval of the Jackpine
Mine – Phase 1. Submitted to the Alberta Energy and Utilities Board and
Alberta Environment. May 2002.
Shell Canada Limited. 2005. Application for Approval of the Muskeg River
Mine Expansion Project. Submitted to the Alberta Energy and Utilities
Board and Alberta Environment, April 2005.
Request Appendix 4-1, Section 1.3.2, Page 102.
Shell states, “The substances considered in this assessment represent a range of
dissolved compound behaviors, including conservative (non-retarded and nondegradable),
retarded and degradable constituents.”
79a Discuss the chemical behavior pattern for non conservative constituents
(Naphthenic acids and polycyclic aromatic hydrocarbons (PAHs)) in
groundwater aquifers in terms of their adsorption tendency, fractionation
(daughter products), organic carbon partitioning and oxidation-reduction
potential.
Response 79a The chemical behaviour of the indicator constituents included in the solute
transport model, in terms of adsorption tendency (Kd) and anaerobic decay (halflife),
are listed in EIA, Volume 4B, Appendix 4-1, Table 12. Organic carbon
partitioning coefficients (Koc) for naphthenic acids, PAH Group 2 and PAH
Group 8 were included in the distribution coefficients (Kd) by applying an
organic carbon content fraction of 0.006 in the function Kd = Koc*foc. In the
surface water quality assessment, retardation of PAH groups that were not
April 2010 Shell Canada Limited 7-37
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