The National Labor Relations Board is taking aim at newly adopted constitutional amendments that bar a federally recognized path for workers to unionize: signing cards authorizing a union. The NLRB has threatened to file lawsuits against Arizona, South Carolina, South Dakota and Utah to block the amendments. The board contends the measures conflict with the National Labor Relations Act and are pre-empted by the U.S. Constitution. The amendments all were approved on Nov. 2. South Dakota’s took effect on that date; Utah’s took effect on Jan. 1. The North Dakota and South Carolina measures are to take effect soon. In
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.