Mr. Brian Kynoch reports
IMPERIAL METALS CORPORATION: MOUNT POLLEY REMEDIATION UPDATE
Imperial Metals Corp. has provided an update on the recovery efforts related to the Aug. 4 tailings impoundment breach at its Mount Polley mine. The initial response and recovery phase have been substantially completed, and crews have commenced rehabilitation and restoration activities.
Response and recovery phase
The initial response to the tailings impoundment breach included a program to secure the remaining tailings within the impoundment, reduce the water level in Polley Lake and clean up woody debris deposited in Quesnel Lake:
- Tailings security: A rock berm was constructed upstream of the breach
area to secure the remaining tailings. Additional rock berms were also
placed inside the tailings impoundment to further secure the remaining
tailings and establish sumps to collect water.
- Polley Lake water level reduction: Approximately six million cubic metres
of water flowed into Polley Lake from the breach and was trapped when
the outlet to the lake was plugged. The resulting lake level was 1.7
metres higher than it had been prior to the breach. Eight pumps were
installed to pump water out of Polley Lake, around the plug and into
Hazeltine Creek through two pipelines. Polley Lake has now been returned
to near prebreach level and is now only pumped as required to maintain
the level.
- Quesnel Lake wood recovery: The flow path of the water and tailings
dislodged and deposited trees and bushes in Quesnel Lake, posing a
navigational hazard. On Aug. 4, a team was formed, led by local
contractors working with two boom boats, a barge and four smaller
support craft. Floating wood was secured, following which crews began
the cleanup of beached debris. The wood recovery cleanup is expected to
be completed by mid-November.
These recovery efforts and related safety issues, which are now largely complete, were required to be conducted prior to Imperial proceeding with the rehabilitation and restoration phase. Where possible, Imperial initiated some restoration work concurrent to the recovery efforts.
Environmental monitoring
The Mount Polley environmental monitoring program has been continuing since the tailings impoundment breach. The data collection program includes water chemistry at sampling stations at multiple water depths in Quesnel Lake, and has confirmed the water is safe to drink and is not toxic to aquatic life. Water quality information has been communicated to the local community and stakeholders on a regular basis. The program also includes geochemical, physical limnology and biological testing. This program will continue for the foreseeable future.
Causation review
Geotechnical work is currently under way to determine the root cause of the tailings impoundment breach. This work program includes mapping, geophysical surveys, drilling, test pitting, and testing and analysis of samples from these field activities. The data collection phase of the review is expected to continue until mid-November. The government-appointed panel is to deliver a report on its findings by Jan. 31, 2015.
Rehabilitation and restoration phase
Imperial has assembled a group of experts with global experience to carry out a program of rehabilitation and restoration in the areas affected by the breach:
- Hazeltine Creek: The Gavin Lake Road and Ditch Road bridges over
Hazeltine Creek have both been repaired. Rehabilitation of Hazeltine
Creek will include reconstruction of the channel and restoration of
riparian habitat along the creek banks. Construction of a set of
sedimentation ponds has commenced in the lower reaches of Hazeltine
Creek to remove suspended solids from the water before it enters into
Quesnel Lake. A revegetation program will be implemented to reestablish
a productive ecosystem and for water management to control
sedimentation. An initial seeding of fast-germinating grasses was
completed on all exposed areas in Hazeltine Creek. The rehabilitation
will include the establishment of spawning and rearing habitat for fish.
- Polley Lake: The outlet of Polley Lake will also be restored to
reconnect Polley Lake to Hazeltine Creek. This will be completed by
building a new channel with consideration for access by fish from Polley
Lake to spawn in the upper reaches of Hazeltine Creek.
Communications
Imperial's stakeholder communications outreach has resulted in seven public meetings in the community of Likely and four first nation community meetings to date. In addition, Imperial has hosted tours of the mine and surrounding area for stakeholders, and has met one-on-one with impacted residents and other local groups. The Williams Lake Indian Band and Soda Creek Indian Band have provided an invaluable partnership during this time, supplying workers and contracting partners on a timely basis. Communication with stakeholders is continuing.
General
Imperial maintains its resolve to mitigate the effects of the breach and restore the tailings impoundment at Polley Lake and Hazeltine Creek. Imperial continues to work closely with regulators, the community and first nation partners to facilitate these plans. The matter of operations resumption will not be addressed until after the results of the geotechnical investigations are received.
Additional information on the Mount Polley remediation progress is available at the Imperial Metals website.
We seek Safe Harbor.
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