Breakthrough for Rio Tinto’s smelter hydropower project in British Columbia

MINING.com Editor | October 12, 2021 

Kemano T2 Break through. Image from Rio Tinto.

In a major milestone for Rio Tinto’s Kemano T2 hydropower project in British Columbia, the tunnel boring machine has broken through to the other side.


The Kemano T2 Project is completing a second tunnel to carry water into the Kemano Powerhouse, to ensure the long-term reliability of the power supply for Rio Tinto’s BC Works smelter in Kitimat.

The tunnel boring machine cut 7.6 kilometres through the rock in remote mountains over 30 months, completing the route for a 16 kilometre tunnel that was started in the early 1990s.

“This is a significant milestone towards finishing the second tunnel and securing the long term reliability of hydropower for Rio Tinto’s smelter in Kitimat, which produces some of the world’s lowest carbon aluminium,” said Kemano T2 Project Manager Alex Jones in a media release.

“Boring this tunnel is a highly-skilled and technical feat that has been achieved in an extremely remote location that is only accessible by air or sea. We thank all of our partners who are supporting this important project – from our employees, to contractors, First Nations, government and community members,” said Jones.

The 1,300 tonne Herrenknecht tunnel boring machine is named tl’ughus by the Cheslatta Carrier Nation after a legendary giant monster snake and is decorated with artwork by Haisla Nation students. It is 190 metres long and more than six metres in diameter.

The tunnel will be filled up with water in the middle of next year, with the project expected to be complete in the second half of 2022.