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Near Experimental Hall—Dig This!

In mid-November, workers began excavating the underground facility by digging a pit layer by layer. A drilling rig gouges out rows of 40-foot-deep angled holes into the walls of each layer.


Steel anchoring rods are cemented into these holes to support the structure. Shot-crete—a sprayable concrete—is then applied over a welded-wire mesh to form a solid wall.


Excavators then dig the next layer and the process begins again. When complete, the open pit will be four stories deep.  

—Brad Plummer
    SLAC Today, December 1, 2006

Images courtesy of Bob Law.