Products 01/05/2011 Tunnel Construction: Custom Multi-Armed Rig Drills Deep In a brief follow-up to the Atlas Copco Boomer XL3 D featured in ENR’s Nov. 3, 2010, issue, a custom-built Atlas Copco Boomer XE4 C drill rig currently is being used to dig a rail tunnel near Gothenburg, Sweden. Tunneling contractor Veidekke, Oslo, Norway, is employing the fully computerized unit to drill all the pre-grout holes as well as blast holes in the tunnel. The machine’s four booms were equipped with COP 3038 rock drills and feature the new Auto RHS E rod-handling system for drilling up to 30-meter-deep grout holes
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.