So how do you get rocks as big as houses of the Interstate? The North Carolina Department of Transportation says it'll take three months and three phases.

The Oct. 25 rock slide closed the Interstate at Exit 20 in North Carolina and at Exit 451 in Tennessee.

Phase 1

· Rock in the lower and middle sections of the slide that is still unstable will be removed.

· Large boulders that fell will be blasted into smaller pieces.

Phase 2

· The rocks removed from the side of the mountain and the pieces of blasted boulders will be used to construct a ramp that will enable specialty equipment to

"climb" to the top of the slide area using a pulley system. Specialty equipment is en route from New York (for photos, please visit the Newsroom section of www.ncdot.gov and click on this release).

Phase 3

· Crews will begin removing rock from the top down to the bottom and stabilizing the slope. This work involves chiseling off rock (on a smaller scale, this is like using a hammer and pry bar) and blasting to stabilize the area. As crews work down the slope, experts will analyze each boulder to determine whether it is secure or should be removed. The area above the top of the slide will also be stabilized.

Once all debris is cleared, temporary asphalt will be laid on the highway so that traffic can be restored until permanent asphalt can be laid in the spring.

The slide is about 150 feet high and 200-300 feet wide and the majority of debris is rock. Because of safety concerns while work is taking place, travel lanes will likely not open until all work is completed, which is expected to take about three months. Estimated cost is $2 million to $10 million. Time and cost estimates will be revised throughout the work.

Gov. Beverly Perdue is expected to make an emergency declaration, which will enable the state to ask the Federal Highway Administration for federal funding.

Geotechnical scientists and engineers do not know the exact cause of the slide, but are looking at several potential factors, including possible tremors; freezing and thawing of water in cracks in a wedge in the slope, causing expansion and contraction of the rock plates.

TRAFFIC ALERT:
Travelers can still reach Western North Carolina via a number of routes. An official detour has been set up for inter-state traffic. Motorists traveling west to Tennessee should take I-40 West to I-240 West (Exit 53b) in Asheville to I-26 West (Exit 4a). Follow I-26 West from Asheville to I-81 South (Exit 8a) in Tennessee, back to I-40. Eastbound motorists will follow the reverse directions. A map is attached.

Related Links

1. Map of Rock Slide Area
2. DOT Traffic Information
3. DOT Twitter Account