Lower Mattagami River

The Lower Mattagami River Project is a $1.7 billion investment into clean, renewable energy. It is the largest hydroelectric power generation initiative in nearly 40 years in Northern Ontario. Ontario Power Generation (OPG) selected Kiewit-Alarie, a Partnership (KAP) to administer the design-build project on the Mattagami River. 

This project will see the retirement of the old 52 MW Smoky Falls Generating Station, and the construction of a new 271-MW station immediately adjacent to the existing plant. In addition, a new generating unit will be added to three other power generating stations along the Mattagami River: Little Long, Kipling and Harmon. In total, OPG aims to increase Ontario’s energy generation capacity by over 440 MW, enough electricity to power 330,000 to 400,000 homes. 

The project required the excavation of 650,000 m3 of overburden and over 700,000 m3 of rock, as well as the placement of over 190,000 m3 of concrete over five years. 

The project is expected to have minimal environmental impact since no vegetation removal or right-of-way widening is required and construction crews will use existing access roads. It also provides an opportunity for employment and specialized training to First Nations.