Pierre River Mine Project

WATER AENV SIRS 15 – 43
Question No. 30
Request Volume 2, SIR 298a – d, Page 21-53.
Section 12.1
It is likely that the polishing pond temperatures for Jackpine and Pierre River
will be within close range of each other. Similarly, the Muskeg and Pierre River
streams also exhibit comparable water temperature regimes. On this basis, the
four questions (i.e., SIR 298 a – d) are applicable to Pierre River.
30a Provide answers to the four questions posed, in terms of polishing pond
temperatures of the Pierre River project and the streams of the Pierre River
project that flow to the Athabasca River.
Response 30a The following are responses to the May 2009 Pierre River Mine, Supplemental
Information, Volume 2, SIR 298 a to d, in terms of polishing pond temperatures
of the Pierre River Mine Project and the streams of the Pierre River Mine Project
that flow to the Athabasca River:
Original SIR 298a
Clarify the first sentence of the pre-amble since most of the polishing pond
temperatures presented in Figure 6.5-2 (Page 6-380) are above the seventy-fifth
percentile of the Muskeg River, and not within the range of monthly background
temperatures.
Figure 6.5-2 shows that the range of polishing pond temperatures (0.0 to 20.6ºC)
is within the range of background temperatures for the Muskeg River (-0.6 to
23.3ºC). Episodic periods of warmer temperature for polishing ponds have been
observed before ice-cover from August to December, and a few were outside of
monthly background ranges (e.g., October 25, 2002). These periods corresponded
to short-term periods of high solar radiation and air temperatures, when bottom
heat flux from the shallow polishing ponds can appreciably affect water
temperature.
Original SIR 298b
How will higher temperatures quantitatively influence downstream temperatures
in the Muskeg River; that is, what will be the new downstream water
temperatures at different times of the year under a range of river stages?
A conservative temperature balance of a “worst-case” scenario for thermal
impacts from polishing ponds releases was calculated as part of the EIA and is
discussed in EIA, Volume 4A, Section 6.5.5.1, page 6-382. It was based on:
• mean September and October streamflows and water temperature for the
Muskeg River
• high flow from the polishing ponds
12-42 Shell Canada Limited April 2010
CR029