Pierre River Mine Project

MINING AND PROCESSING ERCB SIRS 3 – 38
Section 4.1
Response 34e If fines captured in the NST are lower than targeted, a number of options may be
evaluated to address the potentially reduced fines sequestration, including:
Question No. 35
• amending NST production and placement practices to enhance fines capture
• marginal increases in fines content of the NST slurry delivered to the DDA
for deposition to accommodate for fines losses during deposition (i.e.
overshoot fines target)
• supplemental offsets using alternative technologies, such as atmospheric
fines drying of MFT or thickened tailings deposits
Request Volume 1, Section 10.1, Page 10-145, Supplemental Information Responses.
Shell states, “non-segregating tailings deposits will be managed to meet the
requirements of ERCB Directive 074, i.e., NST deposits will be targeted to have a
minimum undrained shear strength of 5 kPa for the material deposited in the
previous year, and they will be ready for reclamation within five years after
active deposition has stopped. The planning basis for final NST deposits will be
to have the strength, stability and structure necessary to establish a trafficable
surface with minimum undrained shear strength of 10 kPa for the surface layer.”
35a Elaborate on Shell’s plan to manage the NST deposit to comply with ERCB
Directive 074.
Response 35a Shell’s plan to manage the NST deposit to comply with ERCB Directive 074 is
based on its current understanding of the technology derived from field-scale
NST performance tests at its Muskeg River Mine tailings test facility. These tests
also form the basis for the tailings management plans filed in accordance with
Directive 074 for the Muskeg River Mine and the Jackpine Mine. Shell expects
that commercial-scale demonstration of these field-scale predictions will be
available before the Pierre River Mine NST operations start up, and that this
commercial experience will be incorporated into the Pierre River Mine design.
Request 35b What is the contingency plan if non-segregating tailings deposits do not comply
with ERCB Directive 074?
Response 35b Shell is confident that the non-segregating tailings deposits will meet the
objectives of Directive 074, i.e. will meet the strength criteria, reduce fluid fine
tailings production, and produce trafficable deposits. See the response to
ERCB SIR 34e for contingencies if fines capture falls below target. If the NST
deposit has a lower undrained shear strength than predicted, adaptive measures
will be taken to enhance the rate of excess pore-pressure dissipation, such as
April 2010 Shell Canada Limited 4-37
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