New York ? The crews at Ground Zero are finally at the bottom of the World Trade Center’s vast basement, sifting through the last heaps of debris.

And now, with less than a month to go, many workers are pausing for the first time to reflect not only on the attacks, but on the accomplishments of 242 days at Ground Zero.

The total hours, roster of workers, tally of injuries and other startling statistics related to the unprecedented recovery and cleanup effort detail a story that is tragic but also inspiring.

“Obviously, no one anticipated prior to 8:46 on the morning of the 11th that the entire city would be focused on the collapsed World Trade Center,” said Kenneth Holden, commissioner of the city Design and Construction Department, which oversees the disaster site. “We have achieved what many thought was impossible on the afternoon of the 11th. That is, namely, that by Memorial Day, all the debris at the Trade Center will be cleaned out from Lower Manhattan.”

Mayor Michael Bloomberg announced last week that the relentless recovery effort will be declared over in three to four weeks. He said he expected to reveal the date of the official closing ceremony in a few days.

A meeting of victims’ families and state and city officials is to take place this week to complete details of the last solemn day.

Since Sept. 11, 19,435 body parts have been pulled from the ruined 16 acres. The search promises to be meticulous to the end.

“Most of the debris has been gone through once, but they continue to find more remains,” said retired firefighter Lee Ielpi, whose firefighter son died in the attacks. “Until all the debris has been removed, it will continue to be a recovery effort not a construction site.”

Ielpi has been at Ground Zero nearly every day since the terrorist-piloted jets hit the twin towers. At the peak of the operation, 3,500 uniformed and civilian workers toiled daily amid the smoldering wreckage; an equal number labored on the immediate perimeter.

“Every able body in the Fire Department has worked down there, whether it be for an hour, a day or longer,” said FDNY spokesman David Billig.

The mountains of mangled steel and pulverized concrete have been reduced to piles that can be combed for the smallest body parts. Some 1,590,227 tons of steel and debris have been carted away.

About 700 workers, police and firefighters are now at Ground Zero each day.

This month, 110 body parts have been recovered. No bodies have been found since late April, and 1,796 victims remain lost.

“Everything’s gone amazingly fast,” said glazier James Healy as he helped rebuild the Winter Garden atrium Saturday. “It doesn’t look anything like it did on the first day. We all worked very hard and did the best job we could.”