Transportation officials say the final blast needed to widen the westbound bore of the Twin Tunnels on Interstate 70 in Idaho Springs is scheduled for Monday morning.
The Colorado Department of Transportation says since the first week of April, crews have detonated 85 blasts to widen the bore to a width of 53 feet. Another blast is scheduled later in the week to remove the structure's rock base floor.
The expansion is part of a $55 million project to ease congestion on the heavily traveled interstate, which links Denver with some of the state's largest ski areas. The new tunnel is set to open to traffic by the end of the year, and the project is expected to be completed next summer.
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