The company said “global demand for tin and tungsten, a metalcommonly used for light bulb filament, was rising fast”.
A piece of tungsten was uncovered in 1867 at Hemerdon but commercial mining ended there in 1944 because of cheaper imports.
The tungsten mine will be 2,624 ft long, 1,476ft wide and 754ft deep.
Humphrey Hale, managing director, said: “The environment is important to all of us.
“We are controlled by Devon County Council and the Environment Agency.”
