Pierre River Mine Project

PIERRE RIVER MINE
SUPPLEMENTAL INFORMATION
PART 2: ERCB SIRS – ROUND 2
Question No. 40
AIR
ERCB SIRS 40 – 45
Section 6.1
Request Volume 1, Section 11.1, Page 11-30, Supplemental Information Responses.
In relation to redundant SO2 pollution control equipment Shell states,“The
current design has an estimated component availability of above 99%.”
40a Provide the overall annual Wet Flue Gas Desulphurizer (WFGD) unit
availability when all the component availabilities are factored in.
Response 40a Each section of the wet flue gas desulphurizer (WFGD) includes spare major
equipment that is critical to ensuring sustained operation of the unit. Sparing the
critical equipment results in a high on-stream factor for the WFGD. The current
design has an estimated component availability of above 99%. The overall
WFGD on-stream availability is expected to be at least the same.
Request 40b Discuss implications to the air assessment if the availability is less than 99%.
Response 40b EIA, Volume 3, Appendix 3-8, Section 4.3, provides the air quality and health
risk assessment for an upset scenario in which the asphaltene-fired cogeneration
unit pollution control equipment malfunctions. Additional information on this
scenario is also provided in the response to SIR 250 in the May 2009 Pierre River
Mine, Supplemental Information, Volume 2, Section 20.
In summary, the predicted maximum 1-hour sulphur dioxide (SO2)
concentrations for this upset scenario are greater than the Alberta Ambient Air
Quality Objective (AAAQO) of 450 µg/m³. The likelihood of exceeding the
AAAQO outside developed areas during an event is 3.8%. This does not take
into account the likelihood of the event actually occurring. The maximum
predicted 1-hour SO2 concentrations are above the AAAQO at Cabins H and K
with a likelihood of exceedance of 0.07% and 0.06%, respectively. While these
concentrations are high and could result in adverse health effects, the likelihood
of this upset event occurring is low, as Shell has committed to redundant SO2
pollution control equipment. In addition, the duration of these impacts is
expected to be brief, because if the pollution control equipment were to fail,
operations personnel would react quickly and switch the fuel for the asphaltenefired
cogeneration unit to natural gas within 15 minutes.
April 2010 Shell Canada Limited 6-1
CR029