New Delhi, Sept. 26: India has acquired on lease real estate the size of Goa and Sikkim put together on the central Indian Ocean seabed to launch an exploratory research programme to search and extract rocky undersea volcanic material for useful metals.

The Union earth sciences ministry today signed a 15-year contract with the International Seabed Authority to acquire exclusive exploration and research rights for 10,000sqkm of area in the central Indian Ocean, along the Central Indian Ridge and the Southwest Indian Ridge.

The programme will look for polymetallic sulfides, materials that precipitate from fluids emerging from upwelling magma from the deep interior of the oceanic crust discharged through chimney-like structures on the seafloor, senior Indian scientists associated with seabed exploration said.

Such polymetallic sulfides are expected to be rich in copper, gold, silver, platinum and zinc among other metals and are viewed as future sources of industrially useful metals.

"This is another step - we're preparing for a future where seabed mining becomes viable," said Madhavan Rajeevan, earth sciences secretary, who signed the agreement with Nii Allotey Oduntun, the secretary general of the International Seabed Authority, an agency set up under global sea law.

This is the second time India has invested in real estate in the central Indian Ocean. India's department of ocean development had in 1987 acquired similar exploration and research rights for a 75,000sqkm area in the central Indian Ocean basin to look for polymetallic nodules, potato-shaped and rich in cobalt and nickel.

The National Institute of Oceanography (NIO), Goa, and the Institute for Minerals and Metals Technology (IMMT), Bhubaneswar, both laboratories under the Council of Scientific and Industrial Research, have been involved in experimental extraction and processing of polymetallic nodules from the earlier site.

"We've established the technology to process 500kg per day nodules to extract cobalt and nickel," Kali Sanjay, project coordinator for the polymetallic nodules programme at IMMT, told The Telegraph. "But the extraction of the nodules from the seabed itself is challenging and not economic yet."

India has very little land-based resources of nickel and cobalt, metals that are used in steel and other industries to make key alloys. "Seabed mining is a long-term goal, but it needs years and years of preparatory activities to reach the seabed, mine the nodules and process them," another scientist said.

The NIO has during experimental extractions used "boomerang grabs" or freefall grabs - devices dropped to the bottom of the sea - to collect the polymetallic nodules. Seabed surveys by the NIO suggest that the abundance of nodules varies from traces to about 25kg per sqm of the seabed.

China, South Korea, and Germany are also engaged in similar seabed exploration in the central Indian Ocean.