When rescue workers pause and gather together still-smoking rubble at the site of the World Trade Centre it usually means the discovery of bodies.
But for the last two days, a big concentration of police and FBI officials seen amid the ruins of the No 4 building on the south-east side has signified an event of a different kind - the recovery of some 1,000 tons of bullion worth more than $320 million.
In a just-opened basement beneath the wreckage, dozens of armed FBI and Secret Service personnel are overseeing the transfer of thousands of gold and silver ingots into white Brinks armoured trucks.
Most of the buried treasure belongs to the Bank of Nova Scotia, one of the world's largest precious metals dealers, which was custodian of 379,036 ounces of gold and 29,942,619 ounces of silver at the time of the attacks on September 11th.
A temporary ramp was built to gain access to a service tunnel and a small bulldozer was brought in to break through a wall. The bullion extracted was held in part of a 16-acre basement complex which goes 65 ft below the twin towers. There too lies property belonging to a number of federal bodies, including Secret Service archives, contraband narcotics, dozens of vehicles and some 400 confiscated weapons.
Ms Pam Agnew, a Bank of Nova Scotia spokesperson, told The Irish Times that from the day of the attacks they had known the vault was intact and the bullion safe but had not sought its transfer because of the urgency to search for survivors and bodies.
"The removal of the contents in the vault hadn't been a priority with us because, obviously, the people came first," she said. "All I can tell you is that the vault remained safe, intact and secure from day one."
The New York Times reported yesterday that officials found suspicious new scorch marks on a basement door leading to the bank vaults, and that a video camera was installed to thwart any attempt to steal the precious contents.
The Canadian bank, whose eight security employees escaped unharmed from the collapsing buildings, placed its own guards near the vaults after the attacks. The vaults are owned by Comex, a division of the New York Mercantile Exchange, where five big metals dealers, including ScotiaMocatta, the metals trading arm of the Bank of Nova Scotia, cleared their trades.
Comex, which used the bullion to guarantee delivery against futures contracts traded at the exchange, said it held 792,170 ounces of gold in inventory with a value of about $220 million and 102 million ounces of silver reserves worth about $430 million at several locations in the World Trade Centre area.
It held bullion for Chase Manhattan Bank, the Bank of New York and Hong Kong and Shanghai Bank.
The Mayor of New York, Mr Rudolph Giuliani, told a news conference on Wednesday that most of the bullion had been moved. "I think we have most of it. I'm not sure we have all of it yet."
A safe containing about $2.7 billion in stocks and bonds belonging to Morgan Stanley Dean Witter, the trade centre's biggest tenant, has also reportedly been recovered It was said to be unlocked when the buildings collapsed and some certificates were burned.
A wrecked Brinks armoured truck was also in the basement but Brinks has denied newspaper reports that it contained as much as $14 million in cash and bonds.
One of the saddest of the discoveries made by rescue workers has been of giant safes containing human remains which fell from offices high in the Twin Towers. A number of employees of financial companies had reportedly taken refuge inside them from the fires caused when the planes struck.