SWEETWATER COUNTY – Forty-eight years ago today was the opening of the Green River I-80 marginal route, better known as the Twin Tunnels. The opening was delayed by early winter weather and scheduling conflicts with the UW Homecoming Game. According to the media reports in 1966, traffic would be open the next morning through the 1,135-foot tunnels.
The construction of the tunnels was reported as being some of the most complex done on the route in Wyoming. The drilling of the tunnels required rock mechanics instrumentation which measured the “…stress, strain and movement of the rock adjacent to the tunnels during the excavation and after completion of the bore.”
Photos from the collection of the Sweetwater County Museum show the drilling of the holes in approximately 1964 and the unpaved road bed leading up to the completed tunnels in 1966.