In the wee morning hours of Dec. 16, a giant boring machine completed a 12-foot tunnel spanning about three miles along Military Drive from Old Pearsall Road to U.S. Highway 90. It’s the longest tunnel segment of SAWS’ massive sewer replacement project near Joint Base San Antonio-Lackland. Only half a mile of tunneling — more than 100 feet underground to avoid disrupting traffic and military activity — remains on the project, which is expected to be completed in 2023.