The company's decision to stockpile Neodymium Praseodymium (NdPr), used in industrial magnets, was to help it consolidate its position as a preferred supplier to customers outside China.
Washington has grown concerned about its dependence on imports of rare earth minerals from China after Beijing suggested using them as leverage in their trade war.
A group of Chinese firms have jointly established a rare earths innovation centre in the country's Hebei province as part of a plan to develop a manufacturing base in the region.
The Malaysian environment ministry has said it wants to discuss ways to manage the low-level radioactive residue produced by Lynas at its rare earth processing plant.
Numerous reports from state-run Chinese media have raised the prospect that China may limit its supplies of the minerals to gain leverage in its trade dispute with the US.
Romania is re-opening mines for rare Earth minerals to lure investments in electric battery plants, joining a Europe-wide initiative that aims for a bigger share of the global market.