Pierre River Mine Project

WATER ERCB SIRS 46 – 79
Section 7.1
Response 68a The basal aquifer is separated from the external tailings disposal area (ETDA) by
overburden and oil sand deposits. Therefore, as there is no direct contact with the
ETDA, it was not considered in the model.
Request 68b Most of the anticipated results are based on the model simulation only. Due to
proximity of the mine and EDTA to the Athabasca River, has Shell considered
any other seepage prevention measures at the source? If so, discuss these
measures and identify the reasons for omitting them.
Response 68b See the response to AENV SIR 17a for the ETDA seepage management
measures that Shell has considered.
Question No. 69
Request Volume 4A, Section 6.1.2, Page 6-229.
Shell states, “Because of its low permeability, the buffer zone will be an effective
barrier to eastward seepage.”
69a Were seismic surveys performed to assess other geological features such as
conduit paths, faults and deep channels which might enhance contaminant flow?
What are the contingency plans in case such features exist?
Response 69a Seismic surveys have not been conducted but it is unlikely that a large-scale
geological feature exists in the mining area if it has not already been identified by
core hole drilling in the mining area.
Question No. 70
If such geological features are identified in future detailed drilling programs for
the Pierre River Mine area, Shell will assess the effects of such features on the
low-permeability buffer zone and implement mitigation measures as appropriate.
One such measure includes installing low permeability barriers, as described in
EIA, Volume 4A, Section 6.3.6.2, page 6-237.
Request Volume 4A, Section 6.1.4, Page 6-350.
Shell states, “Therefore, the general water quality issues and potential mitigation
for the Project were scoped with reference to past EIAs and experience gained by
the assessment team in undertaking those assessments and participating in the
public hearings for the corresponding projects.”
April 2010 Shell Canada Limited 7-23
CR029