Canadian Projects


Ragged Chute hydro project

Owner TransAlta Corporation
Project Hydro Plant / Weir Rehabilitation
Location Cobalt, ON
Size 6.6 MW
Maximum Height 6.9 m
Constructed 1910

The Ragged Chute generating station is located on the site of the historic Ragged Chute air plant, approximately 25 km south of New Liskeard, northern Ontario on the Montreal River. The site was originally developed as a compressed air plant which supplied compressed air to the local mining operations in nearby Cobalt. It was later converted to a hydro generating facility in 1990 by Cobalt Power.

The forebay is impounded by the free overflow spillway, the air plant intake and retaining wall, the intake to the powerhouse, and the earthfill dyke abutment.

The free overflow spillway is an ogee shaped concrete structure that is arched upstream with its right abutment founded in bedrock and its left abutment against the air plant intake structure. The spillway is approximately 91 m long and 6.8 m high at its highest point.

The air plant is a reinforced concrete structure with five timber gate controlled openings that allow water to enter the 107 m deep intake shaft and the tunnel chamber.

The retaining wall extends from the air plant to the left abutment. The retaining wall is a concrete gravity section that relies on the downstream fill for its stability. The intake for the existing 6.6 MW hydro plant is incorporated into the retaining wall. Canadian Projects Limited undertook a dam safety review, provided annual inspections, and carried out dam safety-related rehabilitation work. This included replacement of the original spillway with a new labyrinth spillway.