It produced 536.51 MT (million tonne) coal during FY2015-16.[25] Coal India operates through 81 mining areas in eight states in India. As on 1 April 2015, it has 430 coal mines out of which 175 are open cast, 227 are underground and 28 are mixed mines.[2] Production from open cast mines during 2014-15 was 92.91% of total production of 494.24 MT.[5] Underground mines contributed to 7.09% of production.