On February 17, the Port Authority of New York and New Jersey finished excavating the land for two new towers at Ground Zero. It worked for more than a year to build 80-foot-deep foundations for two towers that developer Larry Silverstein will build, removing nearly 400,000 tons of concrete, soil and rock. Silverstein had said that construction would begin on the towers within weeks after the land was turned over. The agency paid $14.4 million in late fees to the developer for being 48 days behind a deadline it set for itself. The agency agreed to excavate the eastern half of the lower Manhattan site for Silverstein's towers by set deadlines. It has until June to excavate space for a third tower. The skyscrapers, all at least as tall as the Empire State Building, are expected to be built in the next four years.