7.6 km of newly-excavated tunnel
250,000 m3 volume of rock to be excavated
Remote site accessible only by air or sea
Mountainous terrain with high avalanche risk
- BC Works' Kitimat aluminium smelter relies on the guaranteed availability of a stable supply of hydroelectric power that the Kemano Powerhouse provides.
- Located 75 km southeast of Kitimat, British Columbia, Kemano is only accessible by air or sea.
- The 960 MW Kemano Powerhouse receives water from the Nechako Reservoir through a single 16-km tunnel that is over 60-years-old.
- Rio Tinto recognized that a second 16-km tunnel was needed to ensure the long-term reliability of renewable power to the smelter in Kitimat.
- To connect the powerhouse to the reservoir, the new tunnel must be bored through the mountains in a high avalanche risk environment.
- Project construction will occur between 2018 and 2020—through two winter seasons where temperatures sit around minus -10 degrees Celsius and avalanches are common.
- Hatch has been selected by Rio Tinto to provide the engineering, project, and construction management (EPCM) services for the project.
- The project involves excavating a new 7.6 km portion of tunnel and refurbishing an existing 8.4 km portion of the second tunnel to complete the 16 km-long tunnel to the existing penstocks.
- The second tunnel will allow Rio Tinto to conduct repairs and maintenance on the original tunnel without impacting power supply to Kitimat operations.
- The 1,300 t tl'ughus tunnel boring machine (TBM) was purpose-built for the specific ground conditions of the project.
- A mechanical gate will be installed at the existing T2 intake at Tahtsa Lake, which will also have a lower environmental footprint than building a new intake.
- An avalanche control system (Gazex) will be implemented at critical points on the mountains to mitigate avalanche risk during project construction.
- Rio Tinto has involved the Haisla First Nation and the Cheslatta Carrier Nation to ensure that indigenous cultures and traditions are respected.
- The Cheslatta Carrier Nation selected the name for the TBM—tl’ughus—after the legend of the giant monster snake that bored through the mountains, a story that shares many parallels with the T2 project. Students from the Haisla Nation participated in a contest to the design the artwork on the cutterhead of the TBM.
- Once complete, the upgrade is expected to take the 60-year-old Kemano generating station well beyond 100 years.
- The environmental team is introducing a number of controls to safeguard protected species in the area, including fish, amphibians, bears, and mountain goats.
- BC Works' Kitimat smelter produces aluminium with one of the lowest carbon footprints in the world.
- CDN$600M project
- 300-person workforce at peak construction
- 7.6 km length of newly-excavated portion of second tunnel by TBM
- 190 m length of the TBM
- 3 worker camps
- 8.4 km refurbished portion of 1990s second tunnel
- 16 km length of completed second tunnel
- 250,000 m3 volume of rock to be excavated
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