Tennessee Department of Transportation officials knew there was danger on the Polk County mountainside that dissolved in a rock slide last week, but they say a convergence of problems prevented them from stopping it.
"You can always say there may be a problem here some day," said Vanessa Bateman, Tennessee Department of Transportation geologist. "But is that next week, next year or is that 50 years from now?"
The U.S. Highway 64 rock slide has completely blocked the winding scenic route along the Ocoee River and will continue to do so for at least two more months, officials said Monday. It will cost $2.1 million to clear.
TDOT tries to prevent slides and has even worked on loose rock on the same highway this year, but there are hundreds of other problem sites across the state, said spokeswoman Julie Oaks. Though all problem zones are monitored, it's too costly to prevent all rock slides, she said.
"It's difficult to get in here and do a lot of mitigation," Ms. Oaks said.
The fact that the U.S. Forest Service owns the mountain, the state controls the road and the Tennessee Valley Authority has a dam just a few yards away is another layer of snarl. Working on the loose rock would require getting approval from all three agencies, she said.
"It's a difficult situation," she said. "But our rock-fall mitigation program is pretty aggressive."
It's not very difficult to spot problem areas, said Dr. Ann Holmes, a geologist at the University of Tennessee at Chattanooga, but stopping every potential slide would be an exercise in futility.
"Where the layering in the rock tilts to the road ... those rocks have an inherent weakness," Dr. Holmes said.
The rocks are like very large tiles that are stacked and then tilted, she explained. Once water is added -- as it was during recent rains -- the moisture acts as a lubricant and allows the rocks to slip and slide to the road.
"They are going to slide at some point," Dr. Holmes said. "It's just a hazard you have to deal with."
On Monday, TDOT announced it had awarded a $2.1 million contract to get U.S. 64 repairs under way, but officials say there's no precise way to know how long it will take. First the mountain must be stabilized so another pile of rocks doesn't fall onto the road, then the already fallen rock must be removed, then the road must be repaired.
The eight-week estimate "is a guess at this point," TDOT Commissioner Gerald Nicely said while speaking at the site Monday. "That's what we are shooting for. ... These things are usually very unpredictable, and we are trying to be cautious and conservative."
The rock slide tumbled across the road on Nov. 10 as video cameras recorded the action.
But the rocks at the top of the mountain are still very unstable and must be dealt with first, officials said.
Sevierville, Tenn., contractor Charles Blalock and Sons Inc., will first haul large rocks out with a crane, then use small explosives to loosen others. Large, 40-foot poles will be driven into some of the rocks in an attempt to prevent those from moving in the future.
The final portion of the project will be to remove the rocks on the road and then repair the roadway.
"This is dangerous work," said Paul Degges, TDOT's chief engineer. "The material can continue to move, so we are going to have to continue to work with our geotechnical staff to make sure we are doing this in a safe manner."
Thompson Engineering, which has an office in Chattanooga, will provide daily safety analysis, officials said.
Until the slide is cleared, traffic is being rerouted along state Route 68 through Tellico Plains and Sweetwater, Tenn. The detour more than doubles the trip time between Copperhill and Cleveland.
The rock slide adds fuel to an already heated push for an alternate route in the area. The so-called Corridor K project -- a safer, four-lane road to replace the curvy two-lane one -- is necessary for the area, said Denny Mobbs, a Polk County lawyer who sits on the committee lobbying for the new road.
He says TDOT officials have told him there are more than 160 potential rock slides in the Ocoee Gorge alone, and he fears for the safety of motorists.
"My wife drove that route for many years, and it's only fortuitous that she was not involved in a horrible accident," Mr. Mobbs said. "On top of that, this road closure means multiple wasted hours round-trip for many residents."
Mr. Nicely signaled some support for the project Monday.
"I think we need to start looking at the money we've got for Corridor K," Mr. Nicely said. "We are still in the environmental (study) phase right now, and that's a long and arduous ordeal, but I am hopeful we can expedite that process and work with the funds we have available."
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BY THE NUMBERS
* 30,000 -- Cubic yards of material needs to be removed from the road
* 3,000 -- Truckloads of debris will be transported
* 3 -- State and federal agencies working on the site
* 15 to 20 -- Workers to help stabilize the mountain and clear the road
TDOT's recommended detour route from Chattanooga and Cleveland toward the Copper Basin or McCaysville, Ga., is north on Interstate 75 to Exit 60 at Sweetwater, Tenn., then south on state Route 68 to Ducktown. From North Carolina, take U.S. 74 to Ducktown and go north on SR 68.