US stockpiles of the rare earth minerals it would need to fight a war against an adversary like China are a mystery, and experts warn it's a problem

• Rare earth minerals are critical for national defense and industry.
• National stockpile levels are a mystery, though.
• And there are indications that the stockpile is insufficient, worrying experts.

Rare earth minerals are needed to make all sorts of things, from F-35 stealth fighters and night-vision goggles to internet fiber-optic cables and MRI machines.

They are a subset of the critical minerals deemed essential for national security. If the supply chain for these minerals is disrupted, the negative impact on the US could be considerable. Stockpile sizes are unclear, yet there are indications that levels aren't where they need to be.

Part of the military's mission at home is to keep stockpiles of goods like critical minerals on hand for emergency wartime use. Recent government research suggests that Congress knows that the stockpile levels are insufficient, but the numbers aren't made available to the public. That opacity is troubling to some experts.

In the dark on the stockpile

Although the name suggests otherwise, rare earth minerals are not exactly rare — in fact, they're relatively plentiful. But finding them in large enough deposits to mine is difficult, and the refining process, separating the minerals while they're bound up in chunks of ore, is expensive.

China dominates global markets for mining critical earth minerals and the labor-intensive refining process, a challenge for the US given its rivalry with China and dependence on the minerals.

The Biden administration began cutting American imports of Chinese rare earth minerals a few years ago in an effort to decrease US reliance on China for critical minerals. More recently, the White House initiated a push to forge new partnerships with allies for mining and to boost mining investments within the US.

Some experts say the lack of transparency on mineral stockpile levels within the US leaves the public in the dark about what's actually being done to curb American dependence on what the Pentagon calls its "pacing challenge" for the critical minerals it would need in a great-power conflict.

Gregory Wischer, who serves as a mineral consultant for Dei Gratia Minerals and has written extensively about critical minerals, suspects national stockpile levels are well below where they should be given the available information.

"Congress has broad authority to dictate to the Defense Logistics Agency how much minerals they should stockpile and which minerals they should be stockpiling," he said.

But the Department of Defense's consumption rates of critical minerals aren't publicly available either, Wischer added, explaining that it's hard to ensure critical mineral stockpiling is happening correctly if people do not know exactly how many minerals are used in an average year.

Releasing that kind of data, he said, would increase public reassurance concerning wartime preparation. "You need to have ten-times that stockpile amount for a potential conflict because we would be going through munitions so quickly," he said.

Why the stockpile matters

The Department of Defense released its first-ever National Defense Industrial Strategy in January to improve the resilience of the American military supply chain, in part by increasing stockpiles of critical minerals. Submarines, fighter aircraft, magnets used in missiles, radar systems, and drones all require critical earth minerals for manufacturing.

A past report for Congress on rare earth minerals for national defense, for instance, noted that a single Virginia-class submarine requires 9,200 pounds of REM, while an Arleigh Burke-class destroyer requires 5,200 pounds.

US partnerships with Pacific allies for mineral mining and processing are options for decreasing US reliance on China during peacetime, but Wischer argued that relying on safe ocean supply lines to move processed or raw minerals might not make a lot of sense when preparing for and waging a war in the Pacific.

"We're relying heavily on Japan and South Korea for these refined elements," Wischer said. "And if we get into a potential conflict [in the Pacific], those supply chains are in no way guaranteed to have safe transport to the United States." That makes the stockpile even more important.

A congressional report released late last year noted the 2023 stockpile report to Congress, which is not public, "discovered net shortfalls in 88 materials, valued at $14.83 billion."

Necessary for more than just defense

The US military has said that it aims to have "a sustainable, mine-to-magnet supply chain capable of supporting all US defense requirements by 2027."

As part of the "mine-to-magnet" effort — the naming for which is based on the military logistics phrase from "factory to foxhole" — the DoD awarded $20 million to a company called MP Materials to start processing and refining REM at the company's mine in California, the largest REM operation in the US, and the Australian-based mining company Lynas USA has been awarded nearly $260 million from the DoD to build a rare earth processing facility in Texas.

It's unknown when US-based mining operations might be able to operate at a high enough capacity to offset Chinese imports. For now, US-based mining operations can't produce enough minerals to replace Chinese imports.

Fabian Villalobos, an engineer and defense supply chain expert with the RAND Corporation, said that compared to some other industries, the US military is a relatively minor consumer of critical minerals. Industries such as healthcare, petroleum, transportation, and consumer electronics, as well as the Biden administration's push toward green energy, all depend heavily on these minerals.

"The National Defense Stockpile, or the NDS, is the Nation's stockpile for strategic and critical materials," said DoD's Deputy Assistant Secretary for Industrial Base Resilience Halimah Najieb-Locke in a congressional hearing last year. The stockpiles serve "as an important buffer during emergencies. Stockpile reserves allow us to release materials to keep key production lines operating until long-term supply chains are restored."

But in the same testimony, Najieb-Locke also argued that research has indicated that there are shortfalls within defense stockpiles of critical minerals.

"Recent disruptions and adversarial actions have underscored what we have long recognized," she said. "It is more urgent now than ever to build our capability, resilience, and environmentally friendly supply chains for critical minerals."