Lanes on Interstate-70 are open today after engineers uncovered an old vertical mine shaft under the median just west of Idaho Springs.
The shaft is about 15 feet wide and 100 feet deep.
Engineers estimated yesterday that it's about five to 10 feet below the surface of the median.
Colorado Department of Transportation workers were stabilizing the area yesterday.
They closed one lane of I-70 each direction, but the westbound lanes were shifted to the north, so all lanes could be open today.
CDOT region director Jeff Kullman says it's interesting to find a vertical shaft so large.
He says the majority of mine shafts they find are horizontal and don't require this type of mitigation.
CDOT estimates repairs would take about two weeks, but have NO estimated cost.