Under the contract, a contribution of about $258 million by the U.S. government is currently allocated to the project, higher than the $120 million contribution announced last year, Lynas said.
Lynas, the world's largest producer of rare-earths outside of China, said the updated contract follows detailed design work and cost updates for the project.
Lynas' Texas facility will serve both the DoD and commercial customers, and is targeted to be operational in the financial year 2026.
"Lynas is the only commercial scale source of separated rare earths outside of China and our expertise makes us the ideal partner for the DoD as it addresses supply chain vulnerabilities and strengthens national security," CEO Amanda Lacaze said in a statement.
Feedstock for the facility will be sourced from the company's Mt Weld deposit and Kalgoorlie facility in Western Australia, the miner added.
Shares of the company rose as much as 6.5% by 0052 GMT. Lynas was also among the top gainers on benchmark ASX 200 index (.AXJO).
