Muskrat Falls Hydroelectric Generating Facility
One of the first major construction activities at Muskrat Falls was establishing necessary infrastructure at the site. This included building access roads on the south side of the river, installation of an accommodations complex and supporting utilities (water, waste management, communications, etc.), office facilities, and establishing power at the construction site.
Clearing activities in the reservoir area involves removing trees in the planned reservoir area that could impact operation of the generating facility or affect navigation in the reservoir. Work initially started on the north side of the river, with operations progressing on the south side.
Bulk excavation of rock for the intakes, powerhouse and spillway structures was carried out on the south side of the river. Construction cofferdams were temporarily built around these facilities, allowing them to be constructed in a dry environment. When the spillway was ready in 2016, the river was diverted through the spillway. This will allow the north dam to be constructed in the dry river bed.
Two dams will be constructed at Muskrat Falls: the north dam and the south dam. The north dam will be constructed using a special high-density concrete, known as roller-compacted concrete (RCC). The concrete mix is spread by bulldozers, and then compacted by compaction rollers into a series of horizontal layers. The south dam will be a conventional rock-filled dam that will be constructed by building up layers of rock and till material on the underlying bedrock, which will serve as a foundation for the dam. A road will also be built at the top of the dam to provide access. Once both dams have been constructed, impoundment (flooding) of the reservoir will begin.
The area north of the river forms a natural dam. This area, known as the North Spur, is being stabilized as part of the work undertaken at Muskrat Falls. Stabilization activities include installing a cut-off wall to reduce water migration, upgrades to the system of pumps currently at the spur, re-grading steep slopes on the spur, and installing a layer of rock to protect the shoreline on both the upstream and downstream sides of the spur. This work began in 2014 and will be completed prior to impoundment.
The powerhouse will consist of four units, each housing a turbine and generator. When the concrete substructure and steel superstructure for the powerhouse have been constructed, a powerhouse crane will be erected and the four turbines and generators will be installed in sequence.
During construction, work will take place seven days/week, using two, 10-hour shifts each day. An accommodation complex that can house 1,500 workers has been established on the south side of the river.
When construction of the generating facility is complete, the construction accommodations complex and associated administration buildings will be decommissioned.