What a difference a year makes! The Fourth Bore project has been underway for a year, and make some incredible progress.
On the way, we found fossils, saw some stunning pictures, and learned about the ancient geology of our community. Now, only 109.5 meters remain, and the project is on schedule to open in late 2013.
As you can see from the graphic, miners are only 109.5 meters from connecting the two sides of the tunnel. Crews have already begun expanding the first tunnel from the Oakland side. The first round is called “topheading” and the second round is called “benching”. Workers line the tunnel with support (shotcrete, lattice girders, bolts, etc.) throughout both rounds.
For more on the ins and outs of the new tunnel, check out the Caldecott project site.
