Major Blasting in Eastbound Tunnel Near Idaho Springs Complete

July 29, 2013 - Central Eastern Colorado/CDOT Region 1 - Lane restrictions, construction to continue through end of year.

IDAHO SPRINGSAfter more than three months of closing eastbound and westbound I-70 for up to 30 minutes, the Colorado Department of Transportation has completed blasting operations in the eastbound Twin Tunnel near Idaho Springs.

The Twin Tunnels project is one of the first projects underway to improve the safety and mobility along the I-70 mountain corridor. The project includes adding one eastbound lane between East Idaho Springs and US 6 and expanding the eastbound bore of the Twin Tunnels.

An estimated 19,700 cubic yards of rock has been removed from the 635-foot-long tunnel. Blasting operations began on April 19 to remove the rock from the tunnel bore, and crews performed an average of six blasts per week – totaling 70 blasts this year. Blasting occurred at various times of day depending on the traffic volumes and rock conditions in the area. The final blast on the eastbound tunnel occurred today but crews anticipate a few periodic blasts through the end of the year to clear any additional rock that may inhibit construction activities.

“The completion of blasting at the Twin Tunnels is a significant milestone and has been one of the largest challenges we have faced so far in the corridor,” said Jim Bemelen, CDOT I-70 Mountain Corridor Program Manager. “We still have a lot of work on the Twin Tunnels project and on other projects throughout the area to improve the safety and decrease congestion on I-70.”

Although daily blasting is complete, construction near the Twin Tunnels will continue through the end of the year, which may include a periodic blast. In addition to widening the eastbound tunnel bore and adding a third lane, the project will reconstruct the eastbound I-70 bridge over Clear Creek to help flatten the roadway curve at Hidden Valley. With an estimated 300 accidents occurring in this area each year, this part of the project is designed to enhance safety while facilitating better traffic flow.

The remaining construction will require lane restrictions during non-peak travel times in both directions to complete the work. Through the end of the year, crews will complete the tunnel liner, reconstruct the eastbound I-70 bridge over Clear Creek and add the third eastbound lane from Idaho Springs to Floyd Hill. The Twin Tunnels Project is scheduled to be complete in the summer of 2014, with three lanes of traffic open on eastbound I-70 by the end of 2013 and is the first of several projects designed to improve safety and mobility along the I-70 mountain corridor.

For addition project information, visit For current road and weather conditions, you can also call 511, text CDOT to 25827 or download the CDOT mobile application to your smartphone from your App store.