REEx challenges Wall Street to value entire rare earth supply chains, not just mines, ranking MP Materials and Lynas as top picks while flagging USA Rare
Project Profile
Round Top (Sierra Blanca)
Operator
USA Rare Earth
Country
United States
Ore type
Polymetallic / Other
Key Facts
- Operator
- USA Rare Earth
- Country
- United States
- Ore type
- Polymetallic / Other
- Status
- Exploration
- Target year
- 2028
- Location
- 31.2766, -105.4742
- Target elements
Overview
About Round Top (Sierra Blanca)
Round Top is a heavy rare earth deposit in a rhyolite mountain near Sierra Blanca, in Hudspeth County, West Texas. USA Rare Earth owns and runs the project, which its latest quarterly report still describes as exploration stage. The Round Top rare earth deposit matters because researchers report it is unusually rich in yttrium and the heavy rare earths (Pingitore et al.). USA Rare Earth names dysprosium and terbium among them and plans to feed them into its own magnet supply chain.
Where is the Round Top rare earth project?
Round Top Mountain sits about eight miles from the town of Sierra Blanca and three miles north of Interstate 10 (2025 annual report). The deposit is on state land owned by the Texas General Land Office (GLO). It is held under two renewable GLO mining leases covering about 950 acres. Both expire in 2030 unless extended (10-K).
Who owns Round Top (as of October 2026)
In May 2021, USA Rare Earth bought 80% of Round Top Mountain Development, LLC, the company that holds the mining rights. Texas Mineral Resources Corp. (TMRC) kept the rest (Q2 2026 10-Q). TMRC's share shrank to 18.7% by the end of 2025 as USA Rare Earth covered its capital calls (10-K).
USA Rare Earth bought out TMRC, paying in stock, in a deal that closed on August 7, 2026. TMRC is now a wholly owned subsidiary (8-K, August 2026). USA Rare Earth says it is now the sole operator and 100% economic beneficiary of Round Top (10-Q).
What kind of deposit is Round Top?
Round Top Mountain is a rhyolite laccolith, an intrusion of magma that spread between older rock layers and was later exposed by erosion (Pingitore et al., 2018). The rock is peraluminous and high in silica, and a 2018 study in Minerals states that it is not peralkaline. It formed about 36 million years ago (Piccione et al., 2019).
Much of the yttrium and heavy rare earths sits in yttrofluorite, a form of the mineral fluorite in which those elements take the place of some calcium. In 2018, Pingitore and colleagues called Round Top the only known deposit of yttrium and heavy rare earths hosted in yttrofluorite. They report that yttrium and the heavy rare earths make up about 72% of the rock's total rare earth content, a level rarely seen in igneous rock. The Texas Bureau of Economic Geology has put the rhyolite's total rock mass at about 1.6 billion metric tons (Pingitore et al., 2018). Alongside the rare earths, the rhyolite is enriched in beryllium, lithium, uranium, niobium and other metals, a polymetallic mix (Pingitore et al.).
USA Rare Earth says it does not plan to recover the light rare earths at Round Top. Its planned flowsheet is mining, crushing, heap leaching with dilute sulfuric acid, and solvent extraction, skipping the grinding and flotation steps used at most hard-rock rare earth operations (10-K).
Stage and timeline (as of October 2026)
No mine construction has started, and as of its 2025 annual report the company had no declared mineral resources under SEC rules (10-K). In December 2025 it announced an accelerated plan targeting commercial production in late 2028, two years earlier than before (10-K).
The company's Wheat Ridge, Colorado demonstration plant began operating on June 15, 2026, in part to test Round Top ore (10-Q). USA Rare Earth expects to complete a definitive feasibility study in the fourth quarter of 2026 and publish it in the first quarter of 2027 (August 2026 earnings release).
Funding tied to Round Top (as of October 2026)
In January 2026, USA Rare Earth announced a non-binding letter of intent with the U.S. Department of Commerce for $1.6 billion in CHIPS Act funding and loans. Under the letter, the money would be released in phases against milestones, four of them at Round Top (8-K, January 2026). The company signed definitive agreements on June 3, 2026, for up to $277 million in direct funding and a $1.3 billion loan guarantee covering its projects as a whole. As of June 30, 2026, nothing had been paid out (10-Q).
Texas agreed in May 2026 to reimburse up to $14.2 million of Round Top costs through its Semiconductor Innovation Fund (10-Q). REEx argued the grant leaves processing and permitting questions open. None of the company's 2026 filings discloses an offtake agreement for Round Top output. In September 2026, USA Rare Earth said its magnet business had no definitive offtake or sales agreements with customers in place (8-K, September 2026).
Why Round Top matters for heavy rare earth supply
USA Rare Earth describes its business as a mine-to-magnet chain anchored in the United States (March 2026 release), and Round Top is meant to feed it. Until Round Top can meet its feedstock needs, if ever, the company says its Stillwater, Oklahoma magnet plant depends on outside oxide and metal (10-Q). REEx's view is that Round Top is not expected to supply commercial feedstock in the near term. The next public test is the definitive feasibility study, due for publication in early 2027.
Who owns the Round Top rare earth project?
USA Rare Earth. It held about 81% of the project company at the end of 2025, with Texas Mineral Resources Corp. holding the rest, and it completed its acquisition of TMRC on August 7, 2026. USA Rare Earth says it is now the sole operator and 100% economic beneficiary.
Where is Round Top located?
Round Top Mountain is about eight miles from Sierra Blanca in Hudspeth County, West Texas, about three miles north of Interstate 10. The deposit is on state land leased from the Texas General Land Office.
What kind of rare earth deposit is Round Top?
It is a peraluminous rhyolite laccolith. Much of its yttrium and heavy rare earths sits in yttrofluorite, a rare earth-bearing form of fluorite, and researchers report that yttrium and the heavy rare earths make up about 72% of its total rare earth content.
When will Round Top start production?
USA Rare Earth targets commercial production in late 2028. As of October 2026 the project was at exploration stage, with no construction started, and the company expected to publish a definitive feasibility study in the first quarter of 2027.
Is Round Top funded by the U.S. government?
No Commerce Department money had been disbursed as of June 30, 2026. In June 2026, USA Rare Earth signed Commerce Department agreements for up to $277 million in direct funding and a $1.3 billion loan guarantee covering its projects as a whole. The money is released against milestones, and the January letter of intent listed four of them at Round Top. Texas also agreed to reimburse up to $14.2 million of Round Top costs.
Related
Project Data
Resource estimates, grades and rankings for Round Top (Sierra Blanca) are in REEx Insights, along with data on every project REEx tracks.
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