EXP completes concrete gravity dam for Vale in Sudbury

Photo courtesy EXP.

Consulting engineering firm EXP’s earth, environmental and infrastructure groups recently partnered with general contractor Cecchetto & Sons to provide detailed design engineering services and construction quality assurance for the design-build of a new concrete gravity dam to replace mining company Vale’s Wabagishik Side Dams A and B in Sudbury, Ont.

Several independent reviews had determined the dams—located on a topographic low point on a separate bay upstream of the reservoir for Vale’s Wabagishik Power Plant on Ella Lake (Vermillion River)—were in poor to severe condition, with inadequate freeboards for future head pond operations. Vale’s preferred rehabilitation option was to build a new concrete gravity dam downstream from the existing dams, which were used as cofferdams during the construction. With the new dam completed, these cofferdams were removed last month.

“The structural stability of a gravity dam is achieved mainly by its weight from the concrete mass,” explains project manager and EXP water resources and dam engineer Mauricio Del Olmo Gil. “The Wabagishik Dam was entirely founded on bedrock and needed more than 6,700 m³ of concrete to give stability. Our team collected 191 sets of five concrete cylinders for the entire dam, which were tested for compressive strength at the our materials laboratory in Sudbury.”

As the project’s designer of record, EXP provided dam, structural, geotechnical and environmental engineering services and provided ‘issued for construction’ (IFC) drawings for the access roads, crane pads, dam foundation slab and rock treatment, concrete gravity dam and details, sediment and erosion control plans, water management during construction and final demolition activities.

During construction and demolition, EXP provided full-time supervision, quality assurance and engineering support. To close out the project, the firm submitted the as-built report and corresponding drawings.