Tennessee Department of Transportation crews brought in heavy equipment to clear the road. Williamson County Sheriff's deputies were on scene to help with traffic control. Officials said the cause of the rockslide was the increased amounts of rain across the mid-state this past week.
When the rocks fell they landed on the front end of a tractor trailer driven by Dan Rogers. When his cab was hit, he went across the median, and the truck had spilled some fuel on the roadway.
"I saw a little dust falling from the top of that hill over there and I didn't think it was much coming down and then all of a sudden a whole wall of rocks just fell down on me," said Rogers.
Both westbound and eastbound lanes re-opened around 2 p.m.
Officials with the Tennessee Department of Transportation said that this type of rockslide is rare for middle Tennessee but it does happen, especially when the rocks become loose from heavy rain.
"Water, over time, can get in there and in the winter freeze. Then in the summer the extreme heat can cause those rocks to split open," explained Deanna Lambert from TDOT.
Many of Tennessee's roadways are cut into the state's famous rocky top. TDOT keeps track of the many rock walls you drive by everyday.
"Anywhere in Middle Tennessee where we have gone through and built a road we have what we call a rock fall hazard data base and we keep track of anywhere where we've cut through rock to build a road," Lambert said.
In many areas TDOT has installed metal netting alongside the road to prevent the falling rock from reaching the roadway. But that is a costly prevention method.
"At the end of the day a rock slide is very unpredictable, it's an act of nature," Lambert said.
A TDOT geologist inspected the area of Interstate 840 where the rock slide occurred Tuesday afternoon. He found another section of loose rock about 75 feet east of the spot where the rock fell.