Earth: Dig a hole in Australia/China and process it to get rare-earth metals.

Moon: Use multiple rocket launches to boost equipment and people to the Moon. Dig a hole and process it to get rare-earth metals. Send people and metals back to earth.

Hard to see how the Moon version could ever be price competitive. Even if you could pick up rocks of pure rare-earths I do not think it would be cheaper. Still, makes for an easy headline for a NASA chief I suppose.