In the very near future aliens show up near the Earth. After winning the trust of most right-thinking people they exchange some knowledge and goods.
Among the trades the aliens offer a reasonable amount of some other commodity in exchange for the mineral rights to a 1 km x 1 km stretch of land out in a desert somewhere. The land has a few trace amounts of minerals with some value, but nothing humans have the technology to extract in a profitable way at the moment. Agreements are signed and the aliens get the mineral rights.
The aliens create a cylindrical force field about a kilometer in diameter and start extracting the entire volume of earth as one huge core which is slowly and constantly streamed up through the atmosphere to where a giant mothership waits in geosynchronous orbit to collect it. The mothership never seems to increase in size or actually store this tremendous volume of rock anywhere so it’s speculated that there must be a wormhole on board which is transporting the rock elsewhere for processing.