A costly setback for P.A. on two Trade Center towers Tuesday, January 01, 2008 The excavation work for the foundation of two new towers at the World Trade Center has fallen behind schedule by about a month, officials at the Port Authority of New York and New Jersey announced yesterday. The Port Authority was supposed to complete the work on Towers 3 and 4 by today, but expect the work to take another four to six weeks, officials said. Under its contract, the agency will have to pay the project's developer, Silverstein Properties, $300,000 per day for every day beyond today's deadline that the excavation work continues. Port Authority officials said they would recoup that money by taking back a $10 million incentive that had been set aside for Phoenix Contractors, the company doing the digging for the agency. Officials at the Port Authority and Silverstein Properties said the delays -- attributed to a variety of factors -- were not a significant setback. At one building, for example, an extra layer of rock was discovered last week. Also, officials said, scheduling of the work was complicated because of the site's proximity to a the city subway. "You're talking about a gigantic project, the digging and construction of the foundation for two buildings the size of the Empire State Building," said Port Authority spokesman Steve Sigmund. "It's a very ambitious and difficult project. Of course, we would want it to be on time, but you're only talking about a few weeks." "We appreciate how much the Port Authority has accomplished this year, and a few extra weeks to complete everything is a minor bump in the road in the context of this entire project," said Janno Lieber, director of World Trade Center Development for the Silverstein organization. The work required the removal of nearly 300,000 tons of concrete, soil and rock, or enough to fill Giants Stadium, officials said. The material filled enough trucks to form a convoy fifty miles long. Towers 3 and 4, which would both be about 80 stories tall, are being built at the corner of Liberty and Church streets, where the World Trade Center plaza previously had been. Officials said Towers 3 and 4 are supposed to be completed by 2011. Silverstein Properties spokesman Dara McQuillan said the company is preparing to start construction as soon as possible. "Our team of architects, engineers and builders has been preparing for more than a year, and we will advance procurement and other pre-construction activities, so we can hit the ground running as soon as the site preparation work is completed," said McQuillan. The excavation is about 90 percent complete, according to the Port Authority. The foundations are being dug to a level of about 80 feet below street level. The price-tag for the entire World Trade Center redevelopment, including the Freedom Tower and a transit hub, is $16 billion. More than 700 construction workers using 100 pieces of heavy equipment are at the site, officials said. Construction on the Freedom Tower began in mid-2006. Its foundation is complete and the steel frame will begin to rise above street-level in the first part of 2008, officials said.