The giant, 130-ton Wirth roadheader made news when it first arrived in 2010 from Europe to begin the tunneling for the Caldecott Tunnel Fourth Bore through the East Bay hills. Over the ensuing two years, the spiked roadheader chewed through several geological formations, including rock dating back to the Miocene period 5 to 23 million years ago, wearing away a total of 4,000 drill teeth in the process. In October of this year, contractors dismantled the massive machine, signaling the completion of the excavation. The bore is now nearly 50 feet wide and 40 feet tall for its entire 3,389-foot length from Oakland to Orinda, and work is shifting from excavation to final concrete work, with the opening scheduled for late 2013. Stay on top of progress at the project’s newly revamped website. And watch a video of the final stages of tunneling.
While the digging is done, the story of the men who moved mountain and earth to drill the Caldecott Fourth Bore lives on in a collection of gritty photos by Caltrans photographer John Huseby and MTC photographer Karl Nielsen. The “Tunnel Vision” photo exhibit debuted at MTC earlier this year is now traveling to various locations around the East Bay. For a schedule and/or to view the photos, go to the project site.