This project was part of the Mayo Clinic’s plan for West tower expansion in Phoenix, Arizona. Drill Tech was contracted to build the new tunnel from the proposed excavation under the Mayo Clinic, adjacent to the existing utility room and directly under the active Emergency Room. Tight site conditions and proximity to the hospital’s active operations required a minimal job-site footprint from where Blount performed portal shoring prior to tunnel excavation. SEM roadheader excavation was utilized to construct the 13′ diameter 193′ long tunnel. Ground support consisted of lattice girder and shotcrete. During excavation, Drill Tech was required to excavate adjacent to existing hospital foundation piles and protect them in place. Lastly, Drill Tech installed tunnel water proofing and a reinforced shotcrete final liner. During the project, excessive desert temperatures required night only operations and hospital operations were not impacted by our operations. The project was a great success in the overall hospital expansion project and allowed for future passageways under the hospital for future hospital activities.