The Seattle Times

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Mike Siegel / The Seattle Times

Saturday, July 20, 2013

Highway 99 tunnel machine Seattle’s biggest grind

The giant tunnel drill, nicknamed "Bertha," is seen nestled in its launch pit. The white structure at left is a covered conveyor belt to transport excavated dirt to a barge at Terminal 46. At lower right, the white crane will lower thousands of arc-shaped concrete segments that will become the tunnel tube.