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National Grid's tunnel vision: Digging below the Buffalo River

A machine that operates like a coffee grinder will dig a tunnel under the Buffalo River, allowing National Grid to run electrical cables to support the city's emerging power needs.

National Grid on Tuesday showcased the $11 million project, which will extend beneath the river from Ohio Street to Ganson Street.

A cylinder-shaped machine will bore a tunnel 422 feet long — about one and a half football fields — and 6 feet in diameter. The tunnel will be made of steel-reinforced concrete, 18 feet below the riverbed.

Carving a tunnel was considered a better idea than trying to support cables across a section of the river that is 320 feet wide. There's also an aesthetic benefit, since boaters and Ohio Street residents won't have to look at power lines strung overhead, said project engineer Cillian Cotter.

The tunnel boring was scheduled to start Tuesday. A crane will lower the machine to the bottom of a 53-foot deep shaft, next to the Bison City Rod and Gun Club.

The remote-controlled machine, measuring 14 feet long and weighing 29 tons, will carve the tunnel in about 20 days. The front is equipped with knives and discs on its cutter head. As its head rotates, soil, stone and other obstructions pass through the machine, and are crushed and granulated, according to National Grid. The granules are mixed with slurry that is pumped to a separation plant on the worksite's surface.

The tunnel-boring machine will be lowered into this shaft, which extends 53 feet below ground. (John Hickey/Buffalo News)

Workers are finishing another concrete shaft on the opposite side of the river, where the tunnel will connect to Ganson Street. Once the machine completes its work, it will be lifted out on that side.

"This is an exciting project for National Grid, as we look to serve new [electricity] load, new growth that the city of Buffalo is seeing here in the Ohio Street area, the RiverBend area, and ultimately out on the Outer Harbor," said Ken Kujawa, National Grid's regional director.

Kujawa said the tunnel will help the utility address future power needs. "What we don't want to do is be an impediment," he said. "If a new project wants to come and locate in this area, we don't want to tell them, 'Well, it's going to be a few months before we can get you service.' We want to be able to meet the needs of our customers."

National Grid has used similar machines on overseas projects, but never before in the United States. The machine was made in Germany and belongs to Ward & Burke Tunneling.

Cotter, an engineer with Ward & Burke, said carving a tunnel beneath the Buffalo River is "slightly more challenging than the usual project" because of the strength of the rock.

"The local formation of limestone you have here is up there, it's close enough to the strength of granite, it's extremely hard rock," Cotter said. So the machine was outfitted with special equipment on its head to handle that task, he said.

The project started last November and is expected to be completed in July.

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