Speaker: Ryan Marsters, Lithos Engineering

Topic: The Spiro Mine Tunnel Water Supply System Rehabilitation

The Spiro Mine Tunnel was constructed from 1916 to 1924 to drain water levels for a honeycomb complex of mines near Park City, Utah. Historical usage has transitioned from mining support to a skier subway, laboratory, and now as a key water supply component. Early construction relied on drill and blast techniques to excavate layered sedimentary rocks. Early support used timber lagging, which subsequently failed and required periodic replacement with steel sets, split sets, chain link, and more timber. To secure long-term water supply, a multi-faceted approach was taken to rehabilitate the failing initial 400 LF of tunnel with modern support techniques and retain the architectural flavor of the area. Not only was the tunnel support rehabilitated, but the water delivery system beneath the tunnel was replaced as well. This presentation will discuss the design elements, construction issues, and ongoing work.