SEATTLE — Contractors who built the repair vault for the Bertha the tunnel machine two years ago have filed a lawsuit seeking $11 million in extra pay.

The Seattle Times reports that the contractors contend that their efforts working with tough soil conditions cost more than originally anticipated.

Malcolm Drilling Company, which created the 120-foot deep access vault, filed the lawsuit against Seattle Tunnel Partners earlier this year.

Seattle Tunnel Partners is the prime contractors for the future State Route 99 Alaskan Wat Viaduct.

According to the lawsuit, Malcolm contractors had to fend off sloppy soils and groundwater much than expected to access the damaged machine.

The Seattle tunnel was the preferred choice to replace the viaduct when it was damaged in a 2001 earthquake. But the tunnel boring machine broke down in late 2013, leading to a more than two-year delay while it was fixed.