New deposits of graphite, lignite found in Tamil Nadu

The Geological Survey of India (GSI) has recently found occurrences of lignite, graphite, molybdenite and low-grade limestone in the state. This is in addition to the discovery of platinum deposits in the region, said director-general of GSI A Sundaramoorthy on Monday. He was speaking on the mineral scenario in Tamil Nadu during the inauguration of the refurbished economic geology gallery at the government museum in Egmore.

The GSI has established the presence of a 130-km long and 5- to 10-km wide lignite belt between Mannargudi and Bahur in Puducherry. Neyveli and Jayamkondan are located in this belt. "Recently we discovered the occurrence of lignite deposits in Ramanathapuram district. Our team will continue the investigation for another five or six years, and drilling is in progress in Misal area in Boalur panchayat. Lignite in this area occurs at a depth of 325 to 400 m in Neyveli formation, which lies below the Cuddalore formation. We have submitted a report in this regard to Coal India, who will take over the work from here. The GSI has established the occurrence of 1,100 million tonnes of lignite in Misal area," Sundaramoorthy said.

He said the platinum group of elements occurring in Sittampundi and Mettupalayam area are under investigation by the GSI. India imports about six tonnes of platinum annually. The GSI has estimated a reserve of 0.252 million tones of platinum ore in Karungalpatti, Chettiyampalayam, Tasampatti blocks of Sittampundi area and Solavanur, Mallanaikanpalayam and Karappadi blocks in Mettupalayam area. Drilling is going on in both the areas.

The GSI has established an additional graphite reserve of 0.72 million tonnes from Sivaganga area, where it is being mined and processed for some timenow. About 7.91 million tones of graphite reserve with 13% of fixed carbon occurs there, Sundaramoorthy said. GSI has also established resources of molybdenite in Dharmapuri district. "This is the only source of primary ore of molybdenum in the country. A 23-km long belt from Harur to Uttankari has been extensively explored and reserve of 9.96 million tones has been proved. Tamil Nadu Minerals has taken up further work in this belt. GSI will continue to explore this prospect," he said.

Recently, the GSI established the occurrence of about three million tones of low-grade limestone in Sengurichi area in Villupuram district. This is expected to supplement the large deposits of limestone mainly around Ariyalur, which is not able to meet the demand. The state's reserve of limestone has been estimated at 1,282 million tonnes. The recently discovered low grade limestone can be blended with high grade limestone and used in cement industries. After mapping the entire nation geologically, the GSI is concentrating on locating metallic minerals, industrial minerals and coal. A national project for collecting and analysing geochemical samples at 1-km grids is in progress.

The economic geology gallery at the Egmore museum, refurbished at a cost of Rs 1.5 lakh, includes exhibits on paleontology, climatology, environmental geology and planetary geology, said curator of the geology section R D Thulasi Brinda.