Friday, October 14, 2011
Tunnel crews are grinding their way forward on the New Irvington Tunnel Project. Miners excavate in four directions using road headers (tracked tunneling machines) and controlled detonations when necessary to dig out the 18,600-foot (3.5 mile) tunnel.
Over 2000 feet of tunnel has been excavated with approximately 16,600 feet remaining. Last Friday tunnel crews dug out a new daily record of 50 feet for the project. As the crews become more familiar with and how to deal with the variable ground conditions, the mining production has steadily improved each week. Tunnel excavation is estimated for completion in mid-2013 with project completion in mid-2014. Check out www.sfwater.org/nit for weekly updates of tunnel progress.
The New Irvington Tunnel will provide a seismically-designed connection between water supplies from the Sierra Nevada Mountains and the Alameda Watershed to Bay Area water distribution systems. The new tunnel will lay parallel to the existing tunnel between the Sunol Valley south of Highway I-680 and Fremont, California.