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Barnwell

By Debbie Griffith

Students get an up-close geology lesson at the I-40 rockslide

“You are now standing on a landslide.” Two dozen, hard-hat wearing Earth Science students immediately looked at their shoes and waited for the earth to move.

But there was no rumbling rock. Instead, Rick Wooten, a geologist from the N.C. Geological Survey, showed the students geological maps of the “massive creep” in the Hunters Crossing neighborhood near Waynesville, where they were standing.

While not as dramatic as an active landslide, the slowly moving neighborhood gave the class of budding geology students a view of how geology can have real-world applications.

Barnwell

UNC Asheville students get a first-hand look at the geology of the massive I-40 rockslide that closed a main thoroughfare between North Carolina and Tennessee for seven months.

As Wooten explained, the neighborhood is slowly slipping downhill at the glacial speed of one or two millimeters a year, carrying with it at least four homes, one of which already has been condemned due to compromised structural supports.

“We’re continuing to monitor this site with wells that measure the movement underground. It could be that this slide will stabilize, but we won’t know that without a lot more research. We want to be able to predict whether this is a safety issue for residents. That’s what geologists do; that’s what you will do as future geologists,” Wooten told the students.

The slowly slipping neighborhood was in stark contrast to the site of a massive landslide further west near the Tennessee state line that the students visited earlier in the day. The sudden, catastrophic landslide at 2 a.m. on October 25, 2009, shut down Interstate 40 in Madison County and created national news. The 50-mile detour for travelers caused business losses of up to $1 million a day for almost seven months while the highway was closed.

Professors Bill Miller and Jeff Wilcox, who teach Earth Science and Geology, looked at the landslide catastrophe and saw a teaching moment. They pulled some strings with their geological colleagues in the N.C. Department of Transportation and arranged a special tour of the site for their students on a cold February day.

About 30 UNC Asheville students were joined by fellow students from East Tennessee State and Western Carolina universities to experience the engineering marvel of cleaning up a landslide that was initially 150 feet high and 200 feet long and that buried four lanes of I-40 beneath tons of 600-million-year-old schist.

No doubt, there will be more slides in the future. As geologists, it’s our job to see the threat and to try to avert it.”

Even though most of the massive boulders had been cleared from the roadway when the class visited the site, the rugged cliff face, criss-crossed with climbing ropes and stabilization mesh left the students amazed.

“In case nobody’s paying attention, this is awesome,” exclaimed UNC Asheville student J.D. Jorgensen of Black Mountain, whose face was beaming in the cold sunshine. “This is exactly what I want to be doing with my career— studying geology and using it to help people. If they’d hire me, I’d be right here working on this. It’s just awesome.”

Miller, who has taught Earth Science at UNC Asheville for the past 20 years, explained some geological factors that contributed to the massive slide.

According to Miller, the section of I-40 near the slide was blasted into the mountainside near the Pigeon River in the 1950s after a political fight over whether the route from North Carolina to Tennessee should follow the Pigeon River through Haywood County or the French Broad River through Madison County. Despite the geological challenges, the Pigeon River route was chosen. Since 1972, there have been more than 10 slides that have closed down the highway through the rugged gorge area.

“It’s just not a good place for a road because of the fractured rocks and the foliation planes in that area. It was a wedge failure that just took a chunk out of the mountain like you would cut a wedge out of a cake,” Miller said. “No doubt, there will be more slides in the future. As geologists, it’s our job to see the threat and to try to avert it.”

Jody Kuhne, a highway department geological engineer, held the students’ attention at the slide site as he described the cleanup process. “There are bigger slides, yes, but I don’t know of any that have been more dangerous to clear.”

He said that after months of drilling, crushing and hauling away the 200,000 tons of rock that fell from the mountain, the dangerous process of installing 90-foot-long bolts to stabilize the remaining rock has been done by highly skilled workers who are accomplished mountain climbers accustomed to dangling from ropes as they maneuver huge drills.

“I wish we could see them actually installing those bolts, but I appreciate the fact that they stopped work for safety reasons so that we could see this,” said Jorgensen. “You don’t get this kind of information in a classroom. You need to see it, feel it, taste it, and it really helps us connect our classroom work with the real world. We were just studying gravity process in class last week. This is what it’s all about.”

Miller has a well-established reputation at UNC Asheville for bringing geology to life both in the classroom and through field trips. “Last semester we went to the emerald mine in Hiddenite, where they mine the biggest and most valuable emeralds in North America. The emeralds are valued more for in situ mineral specimens rather than as jewelry, with some sold for more than $1 million. We’re the only school that is allowed to go there. These kinds of trips really light a fire in these students.”

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