(WSDOT video from last week, showing road-building in the tunnel section dug so far)

Just announced by WSDOT – the Highway 99 tunneling machine is back in action after “a month of routine and hyperbaric maintenance” that started June 23rd and ended yesterday. WSDOT says, “The maintenance period included more than 40 shifts of work under hyperbaric conditions, changing cutting tools and performing other maintenance in the space behind the cutterhead.” The tunneling machine is one-third of the way – 3,108 feet – along the route, now “located approximately 120 feet beneath Spring Street, tunneling north toward First Avenue.” Two more stops like this are expected, WSDOT says.