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📅 Tue November 17, 2009 - Southeast Edition
Officials with the North Carolina Department of Transportation (NCDOT) believe that a large rock slide blocking both directions of Interstate 40 just east of the Tennessee line could take as long as six months to clear.
The slide happened in the early morning hours of Oct. 25 at mile marker 2.6 in a rugged mountainous area of Haywood County.
As a result, one of the Southeast’s major thoroughfares is closed from Exit 20 in North Carolina west to Exit 451 in Tennessee, forcing a detour that will take motorists many miles out of their way.
Several hours after the 200-ft.-wide (60.9 m) landslide occurred, NCDOT had rushed a crew on site to assess the situation and begin a preliminary cleanup. Initially, it was announced that the cleanup would take about three months to complete and get traffic moving again.
Despite their public stances, though, some NCDOT officials are now privately warning that the slide is larger than first thought. In addition, the weather and the dangerous work of removing loose rock still on a hillside above the roadway will contribute to the total project lasting an extra two to three months.
The cost of the cleanup is estimated to be as much as $10 million, according to the NCDOT.
The state agency has brought in Phillips & Jordan Inc. (P&J), based in Knoxville, Tenn., and Robbinsville, N.C., as the project’s primary contractor. In turn, P&J has hired Janod Inc., of Champlain, N.Y., a specialist in rock clearing and stabilization for more than 40 years, to assist in the work.
What they are dealing with is rock that local geologists say is 600 million-year-old schist, a heavy, close-grained rock that is extremely weathered and very hard, although not as hard as granite.
Officials are not sure what caused the slide, although slides are fairly common along that stretch of I-40, which runs through the Pigeon River Gorge.
A landslide in 1997 just 2 mi. west of the current slide closed the interstate for three months and involved more dirt than rock. The NCDOT said that 98 percent of the 2009 slide is made up of rock.
Recent rains in the area could have caused the slide, as well as the continuous freezing and thawing that occurs over many decades.
“I have seen quite a few rock slides, landslides and mudslides, and although this is by no means the biggest one I’ve seen, it may be the most dangerous,” said Rick Styles, the NCDOT’s resident engineer on the cleanup.
“A lot of rock slid as much as 500 feet down that slope, but it didn’t all come down at once. Some of it lodged against a rock formation that is still way up the slope where we are having a bit of trouble getting it loose and all the way down to the road level where we can manage it.”
Styles said that by the middle of the week after the slide, Janod had men rappelling down the slope and using large crowbars and handheld equipment that uses compressed air to dislodge unstable rock and send it crashing down the hillside.
“At some point in the next few days those crews are actually going to wench a small drill up the steep rock face and drill some holes in the rock in order to set explosive charges to get that stuff off that slope,” Styles said on Oct. 29. “Once all that is done, then we can get up there with a dozer or two and a couple of track hoes and clear rock from the top down.”
In order to get heavy equipment to the top of the slope, crews will use the fallen rock itself to build a ramp up the hillside. The plan is unusual in that the NCDOT usually builds access roads around landslides to move equipment into place, but after careful consideration, it was decided a ramp would work better at this site.
“I would say that there has already been a few thousand cubic yards of material that has fallen off the hillside and there is about the same amount that needs to fall off,” Styles explained. “Once it does, we can then use that material to build a ramp.
He said that the rock will not have to be crushed, but simply moved or rolled into place to make a temporary incline.
Crews have already been able to move some large boulders off the eastbound lanes of I-40 and have broken them up with tractor-mounted hammer drills.
“Right now we have a Caterpillar 330 excavator and a D7 dozer at the site, with another track hoe with a rock breaker on it,” Styles said Oct. 29. “We haven’t been able to use them much just yet because we still have the threat of rocks falling on top of us.”
Styles expected the work to really ramp up by the weekend of Nov. 7-8 and after that as many as 20 people will work seven days a week to clear the roadway.
That means that crews will be working right through the area’s brutal winter months, a factor that is sure to slow down the cleanup efforts, Styles said.
“Winter will definitely be a wild card in all of this,” Styles cautioned. “The slide happened in a rugged area that will get snow and ice when other parts of Haywood County won’t get any.”
North Carolina Governor Beverly Perdue toured the site of the rock slide on Oct. 28 and pledged to reopen I-40 as soon as possible. She also took steps to request federal money to help pay for the work by signing an emergency declaration.
On that same day, the NCDOT announced that the original estimate of having the road open in three months was probably unrealistic. CEG