Wednesday, February 15, 2012
Miracle Mile is a slight exaggeration but the New Irvington Tunnel Project surpassed the one mile mark last week with help of two record setting days of tunneling. Miners typically average 22.5 feet of excavation per day but ideal ground conditions allowed crews to tunnel a daily project record of 70 feet. Two days later miners set a new record and grinded out 83 feet on their way past this significant mile-stone!.
The new 18,600-foot (3.5 miles) tunnel is currently being excavated from three headings using road headers (tracked tunneling machines) and controlled detonations when necessary. Tunneling is estimated for completion in late-2013 with project completion in late-2014.
Check out www.sfwater.org/nit for weekly updates of tunnel progress.