It was a second unveiling, of sorts, for the 142-year-old Alexandria Canal.

Instead of cheering crowds, with canal company officials talking about a bright future of barges laden with wheat, oats and coal as in 1843, yesterday featured city officials and waterfront developers speaking of mutual cooperation and the significance of Alexandria's latest and largest archeological dig.

Lift Lock Number One, the terminus of the Alexandria Canal that linked the city to the C&O Canal in Georgetown from 1843 to 1886, had been buried under 17 feet of earth until recently.

As part of an agreement with the city, developers Savage/Fogarty Companies Inc. unearthed part of the canal and will restore it as the centerpiece of a $125 million office complex: the TransPotomac Canal Center, at the foot of Montgomery Street on the waterfront.

"I'd like to point this out as a most marvelous situation where city fathers, developers and citizen activists cooperated," said Ben Brenman, chairman of the Alexandria Archaeological Commission. "This is the largest urban archeological program in the U.S."

City archeologists and experts employed by the developer expressed surprise that the canal lock and three wooden gates were so well preserved.

"A lock with the gates intact is an example of the technology of the time," said Steven Shephard, an assistant archeologist for the city. "That the gates are in place is . . .unusual."

The excavated canal lock is estimated to be 140 feet long, 16 feet deep and 18 feet across at its widest point. Three wooden gates allowed barges to pass through the canal to the river, where cargo was unloaded onto sailing vessels. Smaller metal wicket gates in the bottom half of the lock gates allowed the water level to be raised or lowered 38 feet.

Competition from the railroads cut short the commercial life of the canal and in 1866 the Alexandria City Council leased the money-losing operation to a private company. The canal was abandoned in 1886.

The city government will be responsible for preserving the massive wooden gates, which were buried beneath the water table.

"One gate is estimated to weigh five tons, mainly because they are so waterlogged," Shephard said. "We're looking for interested parties in the city where they can store gates."

Preserving the gates could be a costly and lengthy process, he said. The city does not have the money to begin the preservation process, which could take as long as two years, but hopes to raise funds from government or private organizations, Shephard explained.

Thomas Swiftwater Hahn, an industrial archeologist hired by Savage/Fogarty, is overseeing the excavation and preservation of the canal, which company officials estimate will cost $350,000.

Replicas of the gates will be installed in the canal and the original gates are to be placed in a 3,000-square-foot Waterfront Museum that the city will operate in space donated by the developer.

The company also will donate a four-acre park at the site.