BP began conducting the first pressure and diagnostic tests on a five-story blowout preventer (BOP) atop its Macando well bore on May 25 in preparation for a “top kill” attempt to stop the oil that has been gushing from the well and into the Gulf of Mexico since the April 20 explosion. In the “top kill” operation, a vessel will pump drilling mud at a rate of 40 barrels to 50 barrels a minute into two 3-in. choke-and-kill lines at the bottom of the BOP. If the mud stops the oil from coming up the well, concrete then would be
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.