Uranium seemingly dominated responses - of the 933 comments posted to date, many "fully support removing uranium" from the list.

Uranium, which was on the 2018 list of 35 commodities, was not evaluated for inclusion after being deemed a fuel, with the Energy Act of 2020 explicitly excluding fuel minerals from the definition of critical minerals, the USGS said.

The proposed list increased to 50 this year after rare earth elements and platinum group elements were split into individual entries rather than being included as groups.

The Department of the Interior is required to review and update the list "at least" every three years.

More time requested

The Copper Development Association has requested a 30-day extension to the comment deadline.

"We appreciate the time and effort that went into preparing the report, but feel that a thorough and complete review will take more time," it said.

"The methodology and technical input for the 2021 review and revision of the US Critical Minerals List states that it sets out a transparent methodology for prioritising commodities based on objective measures, yet it is not possible to replicate the findings of the study even after reviewing the 42-page methodology.

"It is also not possible even after reviewing the 12-page academic paper that the methodology is based on.

"It is further not possible after reviewing the 97-page supplementary materials to that academic paper."

Potash plea

Helium, potash, rhenium and strontium were also removed from the proposed list, although the Michigan Potash & Salt Company has asked for potash to be reconsidered.

"We strongly recommend that potash not be excluded from the 2021 list and believe that its exclusion would represent a threat to US food security as it relates to the lack of domestic supply, supply chain challenges and dependency on foreign imports," founder and CEO Theodore Pagano said.

Lithium support

US-focused, ASX-listed Piedmont Lithium said the Department of the Interior had once again highlighted the importance of lithium in the new draft list.

"Today, the US remains heavily dependent on imports of lithium, creating supply chain and national security uncertainty," it said.

"It is critical for the US to establish its lithium resources for the burgeoning domestic EV market."

Assistant Secretary of the Interior for Water and Science Tanya Trujillo said the USGS's critical minerals list provided vital information for industry, policymakers, economists and scientists on the most important minerals when it came to US supply chains.

"The statistics and information are crucial to understanding America's vulnerability to disruptions in the supply of critical minerals, including data on the worldwide supply and demand for minerals and materials essential to the US economy and national security," she said.

Comments must be submitted before December 9.