Developers Mull Uses for Rare Rock Excavated for Tunnels

Construction on the Second Avenue subway line is kicking into gear this week, prompting developers, contractors, and architects to consider various uses for the rare rock that will be excavated from Manhattan's East Side. Some say the expensive rock, known as "Manhattan Schist," could be used for the construction of a grand project in the region.

The Cathedral of St. John the Divine in Morningside Heights was built from rock recovered when the no. 1 subway line was excavated in 1904. Ellis Island was also expanded during the 1930s when rock and dirt from quarrying the lettered subway tunnels was used as landfill to expand the island to 32 acres from about five acres. The landfill under Battery Park City was built partly with rock excavated from the former site of the World Trade Center.

"I'm hoping that with all the tunnels we're doing, 10 years from now someone is going to be talking about some nice buildings that came out of this," the president of Capital Construction at the Metropolitan Transportation Authority, Mysore Nagaraja, said in an interview. "You're talking about two 22-feet diameter tunnels going almost three miles," Mr. Nagaraja, who keeps a sample of the rock in his office, said. "That's a lot of rock."

His hope, Mr. Nagaraja said, is that a developer would buy the rock from the MTA's contractor, S3 Tunnel Constructors, and use it for construction in New York City.

"We won't know for a couple of months what we have," Mr. Nagaraja said. "If it comes out in a powder form, there's not much you can do. If it comes out in big pieces, that's something."

The first section of the Second Avenue subway line, which would stretch between 63rd and 96th Streets and is expected to open in 2013, marks the first expansion of the subway system in more than 50 years. It raises the long forgotten question of where truckloads of the rare rock could end up.

"Recycling this rock would be a great environmental move," a senior vice president for Tishman Construction Corporation, Richard Kielar, said.

Manhattan Schist, when polished, appears charcoal black, with veins that resemble thick corduroy, according to stone experts. "Developers would be very excited to work with Manhattan Schist if it comes out in a usable form," the vice president of the stone distributor Stonesource, Mark Shedrofsky, said. "It's rich with a lot of depth and a shimmery, almost metallic, veining," Manhattan Schist sells for about $100 a square foot, according to Mr. Shedrofsky. Average granite sells for about $15 a square foot, in comparison.

Developers and architects in the city are making an environmental push to build with materials quarried within 500 miles of the construction site, they said. "If we can work with local materials, that's our preference," a principle for the architecture firm Ehrenkrantz, Eckstut, & Kuhn, Stanton Eckstut, said.

The commercial resale of the rock was not taken into account in the $337 million contract, the project director for Skanksa USA Civil Northeast, Rory Neubauer, said.