Three U.S. companies showcased their engineering expertise as the world watched the dramatic rescue of 33 Chilean gold and copper miners trapped nearly a half-mile underground for more than two months. The miners miraculously survived an Aug. 5 shaft collapse at the San Jose mine in the Atacama desert about 500 miles north of Santiago. Photo: Courtesy Of Center Rock, Inc., Berlin, Pa. American operators used U.S.-made rig and drill bits to bore an escape shaft to miners trapped underground since Aug. 5. Layne Christensen Co., a Mission Woods, Kan.-based firm ranked 18th on ENR’s Top 200 Environmental Firms list,
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.