Crews began clearing the 23,000 tons of rock Sunday night that crashed onto State Route 108 between Viola and Altamont in Grundy County.
The rockslide, which happened around midnight Sunday morning, should take about three weeks to clear.
Detour signs will soon be posted along the curvy two-lane mountain road, costing those that use the now entirely blocked roadway - mostly locals going to and from work - "a little bit of time," according to Tennessee Department of Transportation spokesperson Jennifer Flynn.
"The whole face of the bluff just tipped forward, it just fell into the road and broke into several pieces," she said. "It's basically a hillside and it fell off a bluff."
A Nashville geologist on the scene estimated a single rock to weigh about 2,000 tons, and Flynn said crews are going to need to drill and blast some rocks multiple times before they're moveable.
Geologists don't predict another rockslide soon, but like predicting earthquakes, it's not an exact science.
"You know it's gonna happen," Flynn said. "It might be 50 years from now, but eventually some of the rocks are gonna come down."