The American Exploration & Mining Association was joined by a coalition in filing a challenge last Friday in the Wyoming district court.
Portugal already has the largest copper mine in the European Union, operated by Lundin Mining.
Oversupply and weak prices of materials such as lithium, cobalt and rare earths are dampening cash flows of Western start-ups.
Meeting is considered pivotal for the UN body, expected to finalize its decade-long effort to enact regulations by 2025.
