LEADVILLE, Colo. (CBS4) – Highway 24 over Tennessee Pass opened to single-lane traffic on Monday for the first time since a sinkhole shut it down.
The 100-foot deep hole formed over an abandoned railroad tunnel on July 9. That meant a long detour for people trying to get between Leadville and Minturn.
Just a few weeks ago, there was nothing to stop the hole from expanding. It’s a chimney coming up from a 19th century railroad tunnel.
“As we were in here working we lost asphalt all the way to the center line of the road,” Colorado Department of Transportation Project Engineer Matt Figgs said. “It had been growing two or three feet every day.”
After stabilizing the hole, crews started filling it in with 1,000 cubic yards of flowable fill, similar to cement.
“Those cement trucks, the big mixer trucks that you see, it would basically be 100 of those to fill in that flow-fill,” Figgs said.
Now crews are drilling into the earth and filling the area with a kind of grout.
“Ten-thousand years from now, when the road, when the dirt washes out underneath, we’ll still have a road because all the grout columns.”
There’s still a concern because the railroad tunnel crosses Highway 24 two more times on the other side of Tennessee Pass. On Monday CDOT got funding to use high-tech lasers to map that area.
“Like a 3-D ultrasound basically of what’s down there, and we’ll go back down there with picture cameras to verify what the lasers have shot.”
That won’t happen for a few more weeks, but CDOT says they hope to have the work done and both lanes open by Aug. 8.
While two bicycle races have not been able to go past the highway, it should be about two weeks ahead of time when the USA Pro Cycling Challenge is supposed to come and crest Tennessee Pass.