Project managers are struggling with how to remove “Rainier,” a tunnel-boring machine that is stuck 330 ft underground since last year. Until the rig is moved, the area’s $1.8-billion Brightwater treatment plant can’t be finished. + Image Source: King County Original contractor and owner parted ways after TBM bogged down. The parties are negotiating a claim while a replacement team drills ahead. Related Links: Seattle Membrane Plant Treats to Higher Levels “As of May 1, we have no way to remove it and are still working on a plan,” says Gunars Sreibers, project manager with King County, Wash. The tunnel,
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.