Strongco Equipment has been working with Dufferin since 1985. Just like the requirements for the machines, trust is a big part of their dealer relationship. Dufferin wants and needs both to be ready to go at all times - whether it's turning the key to start the day or picking up the phone to find a new equipment solution.
Dufferin had one Volvo A35E and two A35D articulated haulers so the comfort level was already there. While hitching a ride up the 45-degree-inlet slope inside the Volvo cab with Dufferin operator Wayne O'Hagan, we hear how easy it is. "The Volvo's are really nice. A lot more comfortable than other haulers I've run. I've got good visibility, a rear camera, air conditioning - even a stereo." After making the climb, O'Hagan wheeled around, backed up and dumped his rock payload onto a large mound that is quickly providing a new bird's eye view of nearby iconic Niagara Falls.
O'Hagan and the other Volvo hauler operators at the Niagara Tunnel also get more out 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 right to work - whether it's up the steep grade or traveling growing distances to unload excavated material at maximum speeds up to 57 km/h (35.4 mph).
A 'boring' process.
"A great deal of the TBM was assembled on site," recounted Pimpinella. "This saved transport time and cost. It took four months of assembly and preparation before Big Becky was ready to start cutting away." She's electric powered and armed with a cutting head that weighs more than 440 tons, features 85 disc cutters and delivers torque that ranges from 9,025 kNm (high speed) to 18,800 kNm (low speed).
The TBM was designed for hard rock, but the geology is quite varied, consisting of limestone, dolostone, sandstone, shale and mudstone. Most of the rock is Queenston shale. The softer stone has been a challenge to safely excavate and support with resultant overbreak in the tunnel crown, slowing production. "The TBM was designed to basically thrust itself against the hard, side tunnel walls and drive forward while cutting," illustrated Infanti. "When the side walls are soft or brittle, the TBM doesn't get optimum cutting thrust." This is one of the reasons the project completion date has been pushed to 2013. The projected price tag has risen from $1 billion (CAD) to $1.6 billion.
As of September 2009, the TBM has bored 5,400 m (3.4 miles) toward the 10,160 m (6.35 miles) finish line. TBM progress to date has averaged about 5 m (16 ft) per day. On average the tunnel is 90 m (300 ft) below the City of Niagara Falls.
When the TBM advances forward, wire mesh, rock bolts and steel ribs are installed to support the tunnel crown. Shotcrete is then sprayed in up to 30 cm (12 in) 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 12.8 m (42 ft).
That's a lot of by-product.
What do they do with all the material cast aside by Big Becky? There is a continuous conveyor system that reaches from the TBM cutter head all the way back out to where she entered the tunnel. Conveyor belt extensions are added every 300 m (1,000 ft).
The conveyors transport the estimated 2.4 million m3 (3.14 million yd3) of bulked material and dump it into a pile that is now surrounded by a drop tent structure, erected after production began due to dust issues involving a nearby butterfly conservatory. Apparently the dust was feared to interfere with the mating patterns of the butterflies. Material is moved by the Volvo haulers to the rising 2 km (1.25 mile) long storage area located adjacent to the jobsite on OPG property.
A unique opportunity.
For Dufferin Construction this isn't the biggest job they've done. Several years ago they completed projects where their share exceeded $150 million for the Highway 407 Express Toll Route (ETR) in Ontario and sections of the heavily traveled, 6-lane Queen Elizabeth Way (QEW). But according to Pimpinella, guys are talking about how unique this project is. "It's a job unlike any you'll ever work on again. It's exciting to be in on this one. We do concrete in all types of conditions and areas from highway to municipal, but a tunnel like this is really interesting."
The work goes on around the clock, 365 days a year. The TBM churns 20 hours a day, from 11 a.m. to 7 a.m. Downtime is filled with maintenance for replacement of disc cutters, greasing and conveyor repairs. And despite all that time on the job and in working in a space over four stories high, is claustrophobia ever an issue? "No," said Foreman Infanti. "These are tunnel guys. It's what they do."
Moving it - whatever it is. That's what Volvo articulated haulers do. Here in Niagara Falls, Canada and for nearly 50 years around the globe. Up the steepest of slopes - separating it by a measureable degree from the other haulers. And when they do see the light at the end of the Niagara Tunnel, everyone on this job will step back, smile and then move on to the next job. Because that is what they all do.