Deep below the Earth’s surface, up a 45-degree slope of unstable mud and rock, weighed down with 37 tons (34 t) of materials, one articulated hauler makes the climb — the Volvo. In the challenging conditions of the Niagara Falls tunnel project, Volvo haulers have been more than pulling their weight.
Situated on the border of New York state and Ontario province, the mighty Niagara River has been providing clean-energy to American and Canadian homes since the 1950s. The 36 mi. (58 km) long river runs north from Lake Erie to Lake Ontario and roughly halfway along are the majestic falls, over which more than 3 million cu. ft. (85,000 cu m) of water cascades every minute — and twice that amount when it is not being diverted to the two Sir Adam Beck power stations 5 mi. (8 km) downstream. It is this immense force of nature that a new generation of engineers is trying to capture as a source of renewable energy for hundreds of years to come.
Launched in 2005 and headed up by Ontario Power Generation (OPG), the project aims to provide enough hydropower to generate a further 1.6 billion kilowatt-hours of electricity every year, a 27 percent increase and enough to meet the demands of 160,000 homes. To do this, they must build a third tunnel through which the excess water can flow at a rate of 17,700 cu. ft. (500 cu m) per second. But not just any old tunnel — this one is a hard-rock tunnel with the largest diameter in the world.
Way Out in Front
Such an extraordinary project needs extraordinary machines and at Niagara Falls they have them in abundance.
At 492 ft. (150 m) long, 47 ft. (14.4 m) high and weighing 4,850 tons (4,400 t), the world’s largest hard-rock tunnel boring machine (TBM), “Big Becky”, as she has been nicknamed, is a true behemoth of a machine. By the time she has finished, “Becky” will have tunneled 6.3 mi. (10.2 km) to a depth of 459 ft. (140 m) and dug out enough rock to fill 100,000 haulers. Her cutting head alone weighs more than 440 tons (399 t), features 85 disc cutters and delivers torque that ranges from 9,025 kNm (high speed) to 18,800 kNm (low speed).
As “Big Becky” grinds her way towards them and with the Niagara River kept at bay by a temporary cofferdam above them, Volvo A35E and A35D articulated haulers are hard at work at the tunnel intake area. Each hauler descends the steep slope in reverse, receives its fill of blasted and excavated limestone rock and heads back up the steep, main climb. Close to the top, the operator has to make a complete right turn and go up a shorter but even steeper incline at a 48-degree angle.
Volvos Make the Grade
“We needed a solution. Strongco told us it would be Volvo. It was,” said Dave Infanti, foreman of Dufferin Construction Company, the subcontractors tasked with site preparation.
Strongco is the largest Volvo Construction Equipment dealership across Canada with more than 25 branches. Anna Sgro, the company’s vice president, Multi-Line Division, explained how the Volvos are able to achieve the feat.
“It’s the Volvo transmission, engine and torque converter,” she said. “The drivetrain is optimized with every part having been developed by Volvo to work together, to get the maximum rimpull and get you in and out of where you need to go.”
Hitching a ride up the 45-degree slope inside the Volvo cab alongside Dufferin operator Wayne O’Hagan, he described the comfort in which he works.
“The Volvos are really nice. I’ve got good visibility, a rear camera, air conditioning — even a stereo.”
O’Hagan and the other Volvo articulated hauler operators at the Niagara Tunnel also have enjoyed the benefit of the powerful dump hydraulics, 9-speed transmission for smooth shifting and heavy-duty axles with 100 percent dog clutch type differential lock. No daily or weekly service intervals mean they can get straight to work.
In for the Long Haul
Trip after trip, day after day, 365 days a year, the Volvos make their journeys into the bowels of the earth — and it’s likely they will be on site for some time to come after the project completion date was pushed back from late 2009 to 2013 following unforeseen problems below ground. “Big Becky” the TBM, was designed to bore through hard rock, but as the geology is quite varied, some of the softer stone has been a challenge to excavate. Overbreak in the tunnel crown has slowed production. When the TBM advances forward, wire mesh, rock bolts and steel ribs are installed to support the crown. Shotcrete is then sprayed in up to 12 in. (30 cm) thick to reinforce the tunnel perimeter. Later, a cast-in-place final concrete lining will be installed to arrive at a final inside diameter of 42 ft. (12.8 m).
Job Well Done
Whichever end of the tunnel they are working at, everyone in the workforce — machine operators, foremen, managers and engineers — all agree that they are involved in something special at Niagara.
“It’s a job unlike any you’ll ever work on again,” said Dave Pimpinella, Dufferin project superintendent. “It’s exciting to be in on this one.”
When “Big Becky” does break through to link up the two openings and there is, finally, light at the end of the Niagara tunnel, all the operators, including the Volvo hauler drivers, can drive into the sun setting through the spray from the giant falls below in the knowledge that they have been asked to dig that little bit deeper and, in the case of the Volvos, risen to the challenge with capacity to spare.
This story was reprinted with permission from Volvo Spirit Magazine, 02/2010 Issue 35.
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