Digging work for tunnel machine Bertha’s repair access vault was stopped Thursday after archaeologists monitoring the excavation found a deposit containing shell material.
The discovery may indicate the presence of cultural materials and requires further evaluation, according to the Washington State Department of Transportation. Though no artifacts or human remains were found, the department follows a strict protocol when any archaeological material is found.
The transportation department is coordinating with the Federal Highway Administration, tribal governments and the state Department of Archeology and Historic Preservation.
Crews had dug down nearly 20 feet of 120 feet as of Wednesday afternoon for a vault where Bertha’s front end can be opened for repairs. The digging started late last week and was expected to continue through November
The $2 billion toll tunnel was supposed to open at the start of 2016 but has fallen close to a year behind schedule.