Harrison Western rehabilitated the Spiro Tunnel portal and 5,400 LF of tunnel. The portal entrance was widened during excavation to make room for a historical display cataloging the tunnel’s unique Park City history. HW removed the failed existing support structures throughout the tunnel and replaced them with steel sets, resin and grouted bolts, timber lagging, and shotcrete. As increasingly unstable ground was encountered, HW implemented an innovative structural support strategy while minimizing impact to the project cost.