Kolkata, Aug 23 : The Geological Survey of India (GSI) has delineated 72,000 million tonnes of high grade limemud off the Gujarat and Maharashtra coasts, which can work as an alternative of chemical grade limestone, scarcely available in the country so far, an official said here on Thursday.
The offshore limemud has been located in an area covering 6,603 sq.km at a water depth of 55-120 meters in the Arabian Sea, around 80-100 km off the coastline, and contains significant amount of chemical compounds that have high requirement in the glass and steel smelting industries.
"It is a significant discovery by the GSI's marine and coastal survey division as the values of 'Calcium-Oxide' (CaO), which is accounted for the quality of limestone, is reasonably high in the found limemud (46-52 per cent).
Also the material is light, free flowing and situated at a minable depth. So the mining would be easy. It has the potential to become an alternative of high grade limestone that is scarcely available in India," Dinesh Gupta, Director General of GSI, told the reporters here.
"The total consumption of limestone was 242.45 million tonnes in India during the year 2016-17.
About 97 per cent of the total production of lime stone in India is cement grade, while just two per cent of it is iron and steel grade and one per cent is of chemical grade.
So India's industrial requirement for steel, blast furnace and chemical grade limestone are met from imports so far," he pointed out.
The official revealed that though the quantum of the limemud deposit was assessed before, the chemical content found in the deposit has been identified recently.
"It has also been found during testing that the quantity of hazardous materials like Silica and Alumina in the limemud is within permissible limits of around one per cent.
So the entire material of limemud can be utilised as it would generate zero waste," Gupta said.
He said 12 blocks of limemud, discovered within the Indian Exclusive Economic Zone (EEZ) is within the mining limits and the cement and iron industries can take the lease and mine the region to use the material.