07/18/2012 04:56 pm ET Updated Dec 06, 2017

Giant Sinkhole That Opened Up On Colorado Highway Expected To Be Repaired By August (PHOTOS, VIDEO)

"Say goodbye to the giant sinkhole!" a post on the Colorado Department of Transportation's (CDOT) Facebook page read on Tuesday.

CDOT announced this week that repairs to US-24 will begin Wednesday and are estimated to take a month at a cost of about $1.5 million. The highway is expected to reopen the week of August 6.

"We're doing everything we can to get the highway reopened as soon as possible," Joe Elsen, CDOT Program Engineer said in a press statement. "The contractor is already mobilizing equipment today and will be provided incentives to finish the project ahead of schedule."

In the coming weeks, crews will stabilize the void under the highway, fill it with a grout material and then mill and pave a new layer of asphalt over the former sinkhole site.

The giant sinkhole that opened up alongside Highway 24 near the top of Tennessee Pass last week grew to 30 feet by 30 feet wide and 100 feet deep. Pieces of asphalt from the highway started to crumble and fall into the sinkhole toward the end of last week.

CDOT issued a statement last Thursday saying that the "sinkhole" isn't really a sinkhole at all, rather it's just a hole caused by the soil giving way above an abandoned railroad tunnel.

After several engineers, maintenance supervisors and geological experts examined the sinkhole, it was determined that it is actually a century-old railroad tunnel that collapsed decades ago.

CDOT is also working with state historians and is referencing archival materials to build a full history of the tunnel and roadway and will continue to do so during the repair effort.

The depth of the hole is estimated to be about 100 feet, and since the depths reach so far into the earth, much of the soil was still frozen until very recently -- when the soil thawed, the hole was exposed.


The collapsed tunnel was reportedly once part of the old Denver and Rio Grande Western's Tennessee Pass Route. It was constructed as part of the Royal Gorge Railroad route in the 1880s, The Denver Post reports.

According to 9News, Union Pacific now owns it and said the tunnel has been abandoned since the 1950s.

All of US-24 is not closed between Red Cliff and Leadville, however it is closed at the section near the sinkhole from mile marker 166 to 162. Crews remain on-site to enforce the closure 24 hours a day, seven days a week. Access to all local roads and businesses remain open. CDOT is recommending using State Highway 91 as an alternative route.

The Colorado Department of Transportation (CDOT) posted photos of the giant sinkhole on their Facebook page.

LOOK: Giant sinkhole alongside US-24 near Leadville, via CDOT:
colorado sinkhole

Additional photos of the US-24 sinkhole and more giant sinkholes from around the world: