Muskrat Falls North and South Dams
Newfoundland and Labrador, Canada
Owner Muskrat Falls Corp.
Design Firm & Structural Engineer SNC Lavalin
Contractor Barnard Pennecon LP
Consultants Keller Foundations; Mike Pauletto Associates; Kleinfelder; Tim Dolan Associates
One of the bright spots in an incredibly controversial and expensive project in Canada is the work Barnard Pennecon performed to build two dams for the Muskrat Falls hydroelectric power project.
Hired to construct a roller-compacted concrete dam in a region where temperatures fall below freezing eight months out of the year, the Barnard Pennecon team built a 39-meter-tall, 450-m-long, roller-compacted concrete gravity dam as part of its work on the complex. The team also built a 325-m-long earthfill dam connecting the powerhouse to a transition dam.
To construct the dams in the dry, Barnard Pennecon built the powerhouse intake cofferdam as well as upstream and downstream Churchill River cofferdams, totaling approximately 650,000 cu m in size.
Construction of the concrete North Dam required diversion of the Churchill River through the spillway. The team used a slope-layer method to place the concrete, which minimized the area of fresh roller-compacted material that had to be protected from the cold and rain at any given time.
The project is in central Labrador on the lower Churchill River. It is a three-day drive from any major city and required an on-site resident camp for 650 workers. All materials and equipment were shipped and stored on-site to minimize weather delays.
The cost of the $9.9-billion project in sparsely populated Newfoundland and Labrador could have to be borne completely by the region’s 530,000 residents if the power from the 824-MW plant isn’t sold elsewhere, or if the Canadian federal government doesn’t follow through with promises to help the province with the cost.
The provincial government conducted a yearlong investigation into the project, and the findings have led the current state-owned Nalcor utility head to call the project “a boondoggle.” The project’s problems were further compounded last October when Astaldi Canada was ordered off the job because of its bankruptcy. Nalcor is now trying to complete the remaining work on its own.