Products 11/17/2010 Tunnel-Digging Rig: Direct-Control System The Boomer XL3 D is a tunnel-digging rig that features direct control by the operator. Intended for large tunnels in civil projects, it can be fitted with a wide range of powerful rock drills for different rock conditions. The rig features a Tier 3 engine and a redesigned operator cabin that blocks lower overall noise levels. Atlas Copco; 413-746-0020; www.atlascopco.com Drill Driver: Subcompact Size The M12 Hammer Drill Driver is 75/8 in. long, weighs only 2.8 lb and is able to deliver 22.9-ft-lb of torque. The tool is powered by a 12V lithium-ion battery
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.