Pleasant Hill is the first stop on a roving exhibition of photographs depicting rare excavation views of the Caldecott Tunnel's $402 million fourth bore project.

"We can't bring the public to the project," said Ivy Morrison, Caltrans public information officer, "but we can take the project to the public."

The Caldecott Tunnel fourth bore project is a partnership of the Federal Highway Administration, the Metropolitan Transportation Commission, the Contra Costa Transportation Authority, and the Alameda County Transportation Commission to build the two-lane fourth bore north of the existing three tunnels.

The exhibit left the Metropolitan Transportation Commission headquarters in Oakland where it's been on display and headed to Pleasant Hill at the beginning of September and will remain at City Hall until the end of the month when it will travel to another city requesting the display, said Morrison.

The photographs present rare views of work inside the tunnel beginning in August 2010, said Martin Nelis, Pleasant Hill public information officer in a news release.

The exhibition pictures taken by Karl Nielsen of the MTC and John Huseby of Caltrans show the primary portion of excavation, including a colossal custom-made 130-ton drill and a now-historic photo of the breakthrough from the Contra Costa County side of the hill where digging began to the Alameda County side.

Proposition 1B passed in 2006 added to the coffers. The