Visakhapatnam: Marine areas off the coast of Andhra Pradesh have a treasure of rare earth elements. This fact came to light as a result of a survey done by the Geological Survey of India (GSI) for mapping and mineral resource evaluation along India’s coast.
Heavy mineral resources up to 1-1.5m thick are available on the sea floor in the middle shelf over an area of 764 sq km with a proven reserve of 108 million tonnes. The survey established that one fourth of the reserves are off Andhra coast.
It has been established that extraction of rare earth elements and Yttrium (REY) is environmentally safe and sustainable due to the absence of radioactive thorium in the host sediments of marine origin.
A reconnaissance survey in the Exclusive Economic Zone (EEZ) for 19,81,478 sq. km. out of 20,14,500 sq. km. has been covered on board three vessels, RV Samudra Ma-nthan, RV Saudhikama and RV Kaustubh that involved over 700 cruises from 1983 to 2014.
The detailed exploration cruises have generated a wealth of data on minerals available including marine sand, silt, and clay. In the light of these surveys, sampling was conducted on 40 km x 20 km grid and laboratory analyses carried out.
The survey managed to gather regional reconnaissance-level geo-scientific information on the nature of surface seabed sediments and potential areas of mineral occurrences.
The outputs are represented in the form of seabed maps. There are a total of 63 maps covering EEZ and 143 covering territorial waters that have been compiled.
“Depletion of terrestrial mineral resources has forced us to turn our attention to mining potential within the offshore areas,” said GSI former director Suresh Kumar Wadhawan in a paper submitted to Indian National Science Academy recently.
“The main purpose of the marine and coastal survey is not only to discover the undersea treasure of minerals but also to unravel the evolutionary history of the formation of seabed morphology and its continuous transformation under the influence of various dynamic processes still operative on different scales in different parts of the globe,” added Mr Wadhawan.
Out of the 764 sq km of potential area, 46 blocks have been notified in the Gazette of India for further exploration and exploitation by interested entrepreneurs. Of them, 14 blocks are off north Andhra coast bordering Odisha.