Permafrost Expansion
The south adit of theEngineerCold Regions Research and Engineering Laboratory's Permafrost Tunnel Research Facility in Fox, Alaska, is clear after the refrigeration evaporator units and safety walkways were removed and more than 50-feet of its interior was improved. The improvements were part of phase four of the expansion of the permafrost tunnel, which excavated a 300 foot tunnel and improved 200 feet of pre-existing tunnel.

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Photo by: Kevin Bjella |  VIRIN: 100420-A-LI860-004.JPG