Ontario Power Generation

LOWER STURGEON FALLS GENERATING STATION

PLANT GROUP: Northeast Plant Group

DRAINAGE BASIN: Hudson/James Bay

RIVER: Mattagami

NEAREST POPULATION CENTRE: Timmins (48 KM (30 Miles) Southeast)

ORIGINAL IN SERVICE DATE: 1923, Re- development 2010

ACQUIRED BY HYDRO-ELECTRIC POWER COMMISSION OF ONTARIO: November 1, 1944

FROM: Northern Ontario Power Company
Asset Transferred to Ontario Power Generation: April 1, 1999

NUMBER OF UNITS: 2 – vertical, double regulated (Kaplan), axial flow directly coupled to air cooled generators operating at 4.16 Kv.

CONTROL: Remote from North East Control Centre (NECC) via a dedicated telecommunication tower.

POWERHOUSE:The building is of pre-engineered structural steel framework, steel clad, insulated walls and sloped roof. The dimensions are 30.9 m (101.4 ft) by 17.9 m (58.7 ft) and is located at the east end of the dam on the footprint of the original station.

FOREBAY AND HEADWORKS: The headworks and powerhouse are an integral part of the concrete dam. Both turbine/generator units are equipped with dedicated trashracks and cable hoist operated 2 piece headgates

DAM(S): The dam is of concrete, combination ogee and pier type. The dam has a total length of 165 m and contains 5505 m3 (7,200 yds3) of concrete. The Main dam has 15 log sluice ways and 1 remote operated sluice gate. In addition to the powerhouse construction, the spillway was rehabilitated to meet current dam safety standards. This work included post tensioned anchors for pier stability and concrete resurfacing of both the upstream and downstream surfaces. A new log lifter was fabricated by OPG and installed on the main dam

SITE: The Lower Sturgeon Falls station is located 37 km (23 miles) below the Sandy Falls station. The total drainage area for this development is 7899 km2 (3,050 miles2).

CONSTRUCTION: The station was designed by RSW Inc, consulting engineering of Montreal and constructed by KAP (Kiewit Alarie Partnership) via a Design Build Contract. Alternate locations for the new powerhouse were explored but sub-surface investigations revealed the original footprint was optimal.

The original powerhouse was de-commissioned and demolished beginning in July 2008, all metals were recycled, concrete rubble crushed and buried on-site, wood debris was disposed of in a landfill.

Construction began with the downstream cofferdam and tower crane installation in the fall of 2008. Powerhouse excavation, drill and blast operation continued throughout the winter of 2008/2009. The upstream cofferdam was constructed in the summer of 2009. As the plant was comparatively isolated, the transportation of batched concrete from the Timmins plant was not practical. Custom Concrete installed a local batch plant on the site access road 6Km from Lower Sturgeon. Total concrete poured was 5500Cubic Metres. The building superstructure was assembled and closed in beginning in January 2010.

Commissioning of auxiliary systems and test operation of the water to wire equipment continued throughout the fall of 2010 with the station beginning commercial operation November 21, 2010.