SEATTLE -- Sound Transit is marking a major milestone on the University Link Light Rail project.
Sound Transit contractors finished boring through a two-mile stretch under Capitol Hill early Wednesday morning, considered the “riskiest” portion of the $1.9 billion project.
"It's a sense of relief when you finish a mining drive like this, especially when you've been underground for two miles," said Sound Transit spokesman Bruce Gray. "To see the face of this machine again, it's a great day."
The giant drill - about 21 feet in diameter - has been digging since May when the project first began. Gray said the drill finished the job three months ahead of schedule.
The tunnel is 300-feet below the surface near Volunteer Park and only 15 feet from the surface near the Montlake Cut. Sound Transit said it hasn't had major complaints about ground instability, as it did during boring through Beacon Hill. Gray said the agency learned hard lessons from that project and is using a different contractor for this tunnel.
This is Sound Transit's largest mining project to date. A second boring machine will begin tunneling through Capitol Hill for the northbound link tunnel and is expected to finish next month.
The new rail route will allow riders to travel underground from the University of Washington to Capitol Hill. It is an extension of the rail route already in place between Sea-Tac Airport and Westlake Center. Sound Transit plans to open the University Link Light Rail in 2016.
KING 5's Jake Whittenberg and Chris Daniels contributed to this report.