Top grade limestone deposit found under Arabian Sea

Kolkata: India's dependence on limestone import for use in various industries is likely to get substantially reduced as a huge under-sea deposit in the Arabian Sea has been found to be of top grade, a top Geological Survey of India (GSI) official said on Thursday.

The depost was discovered off Gujarat-Maharastra coast in India's Exclusive Economic Zone (EEZ), GSI Director General Dinesh Gupta said here on Thursday.

During tests at the Indian Bureau of Mines's (IBM) Bangalore facility, it has been found that Calcium Oxide content is of 46 to 52 per cent in the limemud in that deposit, Gupta and senior scientists of GSI's Marine and Coastal Survey division at Mangalore told newspersons.

The 72,000 million tonne limemud found in the Arabian Sea, 80 to 100 km from the coast and at about 55 to 120 metre water depth, is of the best category given the high content of Calcium Oxide in it, they said.

The limemud, spread over 6,603 square km, has been found to be suitable for use in blast furnaces of steel plants and steel melting shops, pharmaceutical industries, apart from the cement industry, Gupta said.

Stating that the country is short of chemical grade limestone, he said the finding would mean that the nation's dependence on import will reduce substantially once extraction begins following auction of the blocks.

"Mining will be easy given the location and depth of the find," the GSI DG said.

He said following tests at Regional Mineral Processing Laboratory, impurity percentage in the limemud has been found to be very less with almost zero wastage.

Silica and alumina content have been found to be within limit. The GSI has also discovered huge deposits of construction grade sand blocks off Kerala coast in the Arabian Sea, he said.

"The 457 million cubic metre of sand discovered about 10 to 12 km from the coast at a depth of 30 metre have been found in four blocks off Ponnani, Chavakkad, Aleppey and Kollam," Gupta said.

This will go a long way in solving the crisis of construction grade sand in Kerala, he said. The scientists said extracting the sand from the sea will not cause any erosion of coastline since the blocks are situated around 10 to 12 km from the shore.