July 2012
Niagara tunnel nears completion
Big Becky, the world's largest hard rock tunnel boring machine, with the Hatch and HMM team in Niagara Falls, Canada. Photograph courtesy of Ontario Power Generation.

Big Becky, the world's largest hard rock tunnel boring machine, with the Hatch and HMM team in Niagara Falls, Canada
Photograph courtesy of Ontario Power Generation

The Niagara tunnel project involved the design and construction of a 10.2-kilometre water diversion tunnel from the Niagara River above the Horseshoe Falls to the Sir Adam Beck generating stations, along with the associated intake and outlet structures.

The world's largest tunnel boring machine (TBM) – named Big Becky by children from Port Weller Public School in a local competition – is a 150-metre long, 14.44-metre diameter Robbins open gripper TBM.

Big Becky began tunneling under the city of Niagara Falls in September 2006 and, with an average daily advance of 6.1 metres and, finished the job in March 2011. Approximately 1.7 million cubic metres of material was excavated and stored on OPG property between the two existing power canals.

Upon project completion in December 2013, the new tunnel will deliver an additional 500 cubic metres per second of water to the Sir Adam Beck hydroelectric stations to increase their average annual energy production by 14%, or 1,600 gigawatt-hours.

A combined team of Hatch and Hatch Mott MacDonald personnel is providing Owner's Representative services to Ontario Power Generation, and has worked alongside OPG and the construction contractor since early 2006. Hatch's scope includes preparation of design/build contract documents, design review, construction monitoring and contract administration.

For further information, please contact Paul Moorhouse, PMoorhouse@hatch.ca