West Perth-based Greenland Minerals and Energy says its Kvanefjeld project could rival the world's largest rare earths mine in China after a prefeasibility study estimated capital costs at $US2.3 billion ($A2.6 billion).

West Perth-based Greenland Minerals and Energy says its Kvanefjeld project could rival the world's largest rare earths mine in China after a prefeasibility study estimated capital costs at $US2.3 billion ($A2.6 billion).