Victims' relatives this weekend called for a halt to all construction and demanded that state Attorney General Eliot Spitzer investigate why the remains had gone undiscovered for so long. New York mayor Michael Bloomberg has ordered officials to open and search all manholes on the site.

"Oh my God, is that more of Matthew?" said Diane Horning, 59, whose son's remains were located not far from where bones were recovered over the past two days. "It's been sitting there for over five years."

But this week's discovery, which included large arm and leg bones, did not stop workers from continuing to lay the foundation for the 1,776-foot Freedom Tower. Spitzer, who is running for governor, said rebuilding should not halt at the 16-acre site.

Bloomberg, meanwhile, called an emergency meeting at City Hall, ordering a deputy mayor to get all the city's department heads and "put 'em all together in a room" to find out what happened.

A few hours later, deputy mayor Edward Skyler announced all the manholes would be searched, but insisted "established protocols had been followed." The Fire Department, which supervised the vast recovery operation after the 9/11 attacks, refused to comment.

But the 52-year-old machine operator who uncovered the new batch of remains Thursday morning and alerted authorities told the New York Daily News: "It was like a mother lode."

"If a person who has been praying for closure, their prayers could get answered with what was found, " said the worker, who asked to remain anonymous.

Of the 2,749 people killed in the attacks, the remains of about 1,150 victims still have not been identified.

Police sources confirmed more than 80 fragments had been found amid the dirt and muck that Con Edison workers removed from a manhole and utility vault at the northwest corner of Ground Zero. The manhole and vault had sat dormant since the twin towers' collapse.

The machine operator said he spotted the bones after Con Ed workers tore up the temporary road and began "encountering things too big to suck out" with their vacuum trucks.

"I get out of the machine and I saw what looked like what might be bones, " he said. "It was muddy stuff, so I couldn't tell for sure."

The medical examiner quickly determined the bones were human and investigators found more remains, as well as two wallets, at a Con Ed yard on W 29th St to where the trucks had brought the dirt.