NEW YORK (AP) – Seventy trucks rolled into ground zero Saturday to pour the concrete base of the signature skyscraper at the new World Trade Center, creating the first visible signs of the long-delayed tower.

The concrete mixers began by dropping 520 cubic yards of concrete near thin steel bars jutting from the bottom of ground zero. The base will anchor the 1,776-foot Freedom Tower’s concrete core. Next month, the first steel beams for the tower are scheduled to rise.

The site has been bustling in recent months, with work on half a dozen projects under way after years of disputes about designs and authority over the redevelopment.

“We’ve really turned this site around,” said Steve Plate, director of priority capital programs for the Port Authority of New York and New Jersey, which owned the trade center.

The work continued despite calls from some family members of victims to halt construction. A search for human remains is ongoing in the area after more than 200 bones were found in manholes on the site’s western edge. A search on the rooftop of the Millennium Hilton continued Saturday.

Gov. George Pataki’s chief of staff John Cahill said the city needs to be sensitive to families’ needs, but “it is time to build this site.”

For visitors who peer through distant metal fences for a look into the 70-feet-deep pit, it may take time to see the buildings take shape on Manhattan’s skyline. Project manager Mel Ruffini said it would take nearly two years for the Freedom Tower to reach street level.

Work on the Freedom Tower got under way earlier this year after the Port Authority renegotiated developer Larry Silverstein’s lease to rebuild on the site. It is scheduled to open in 2011.

The agency is preparing the eastern end of the site for three more office towers, and earlier this week poured part of the concrete foundation for a permanent transit hub.

Construction of the memorial to the Sept. 11, 2001, terrorist attacks began this spring. This week workers began drilling into parts of the south tower’s footprint to begin building columns that will support the twin reflecting pools meant to symbolize the lost towers.

AP-ES-11-18-06 1935EST

Only subscribers are eligible to post comments. Please subscribe or to participate in the conversation. Here’s why.

Use the form below to reset your password. When you've submitted your account email, we will send an email with a reset code.