Stibnite Hill comeback: U.S. Antimony reopens Montana mine amid rising demand for defense metals

United States Antimony Corporation (NYSE: UAMY) has officially restarted mining operations at its Stibnite Hill property near Thompson Falls, Montana, marking one of the most significant revivals of domestic critical-mineral production in recent memory. The move positions the company at the intersection of industrial strategy and national security, as Washington intensifies efforts to secure reliable supplies of key inputs for energy storage, munitions, and electronics.

The company announced that it had received authorization under Montana’s Small Miners Exclusion Statement to begin immediate extraction over roughly five acres of patented claims. Trucks have begun transporting bulk ore to its nearby flotation mill and smelter complex for testing and refining. Early results reportedly confirmed encouraging ore quality, prompting the company to pursue a second permit that would expand the mining footprint in the months ahead.

This reopening marks the first time in more than four decades that the Stibnite Hill site has produced ore. Operations originally ceased in 1983 amid collapsing prices, but with global supply chains tightening and Chinese export restrictions reshaping the market, the strategic calculus has changed dramatically.

Why the Stibnite Hill restart could reshape the U.S. critical minerals ecosystem and policy landscape

Antimony has re-emerged as a geopolitical metal of consequence. It is essential in flame retardants, semiconductor alloys, ammunition, and next-generation batteries. The U.S. Geological Survey has designated antimony a critical mineral since 2018, but domestic mining capacity has remained virtually nonexistent. For decades, the U.S. imported over 80 percent of its supply, with China, Russia, and Tajikistan dominating global refining.

That dependency became a policy liability when Beijing curtailed antimony exports in 2024. The resulting price surge exposed how fragile Western sourcing had become. Against this backdrop, United States Antimony Corporation’s restart of Stibnite Hill represents a symbolic and material response. The Montana site is adjacent to the company’s Thompson Falls smelter — the only operational antimony smelter in the U.S. — allowing a vertically integrated operation from mine to metal.

The company’s stated plan to scale smelter capacity from roughly 50 tonnes per month to over 300 tonnes by late 2025 underlines an ambition far beyond pilot production. Management estimates that expansion costs will remain below $15 million and that work can proceed without interrupting existing output. That investment, though modest compared to large copper or lithium projects, could make United States Antimony Corporation the first end-to-end domestic supplier of refined antimony in the Western Hemisphere.

Government alignment is also a tailwind. The Defense Logistics Agency awarded the company a five-year, $245 million contract in September 2025 to deliver ingots for the U.S. strategic stockpile. This federal linkage gives the project political protection and revenue visibility, while signaling to investors that UAMY is now viewed as part of the nation’s critical-materials security apparatus.

How investor sentiment toward UAMY evolved alongside its defense positioning and policy momentum

Investor reaction to the Montana restart has been cautiously optimistic. UAMY’s share price rose about 4 percent after the announcement, while daily trading volumes tripled compared to the previous quarter. Market capitalization now stands near $260 million, a sharp recovery from mid-2024 levels when the company’s valuation lingered below $150 million.

Market sentiment data show an uptick in favorable coverage, with news analytics platforms rating the company’s sentiment index well above the broader materials sector average. Analysts highlight that few micro-cap miners hold both a domestic production site and a long-term federal contract, an unusual combination that mitigates some commercial risk.

Still, caution persists. Fair-value models place the stock’s intrinsic range between $4 and $7 per share — below recent trading peaks — implying that optimism about expansion may already be embedded in the price. Institutional flows have been mixed, with energy-transition ETFs increasing exposure while some hedge funds trimmed holdings to lock in profits from earlier gains. Short interest has fallen slightly, suggesting less skepticism but continued watchfulness over execution.

UAMY’s inclusion in several critical-minerals indexes has improved liquidity and visibility, yet its thin free float still magnifies volatility. The stock’s low put-to-call ratio indicates bullish positioning among retail traders, many of whom view the antimony narrative as an overlooked complement to the lithium and rare-earth investment cycle. Whether that enthusiasm endures depends on the company’s ability to sustain production growth and maintain regulatory compliance as environmental oversight tightens.

What operational and environmental challenges could test the long-term viability of United States Antimony Corporation’s restart

The company’s progress at Stibnite Hill will depend on its capacity to balance expansion with environmental responsibility. While the initial five-acre permit allows a quick start, the small scale limits ore throughput and requires sequential permitting to grow. Future approvals will hinge on comprehensive environmental-impact statements addressing tailings management, arsenic mitigation, and water-use recycling — areas of heightened scrutiny from both state regulators and community stakeholders.

Montana’s evolving environmental framework adds another layer of complexity. Recent amendments to the state’s Hard Rock Mining Act have strengthened requirements for financial assurance and reclamation bonding, meaning USAC must demonstrate not only profitability but also credible closure planning. This regulatory landscape contrasts with looser oversight decades ago when the mine first operated, implying that compliance costs will be materially higher this time.

Operationally, antimony’s metallurgical processing presents unique challenges. The element often occurs with arsenic and sulfur, making safe smelting and waste handling capital-intensive. United States Antimony Corporation has stated that it will employ closed-loop water systems and advanced emission-control technologies at Thompson Falls, leveraging lessons learned from previous production campaigns. Nonetheless, environmental groups are expected to monitor emissions closely as the site ramps up output.

Commodity volatility remains another variable. The global antimony price has surged more than 40 percent since early 2024 but remains historically cyclical. Any downturn before USAC achieves full-scale production could compress margins, especially if energy costs rise or recovery grades disappoint. The company’s ability to hedge effectively or secure fixed-price supply contracts through the DLA will be crucial in managing that exposure.

How antimony’s strategic relevance in batteries and defense systems could drive long-term valuation growth

Antimony’s importance extends beyond defense. It is increasingly used in liquid-metal batteries, grid-storage alloys, and as a stabilizing agent in high-voltage lithium-ion chemistries. With U.S. policy now emphasizing domestic energy-storage manufacturing, demand for antimony-based materials is expected to rise sharply through 2030. Analysts forecast that global consumption for antimony in energy-related applications could double within five years, driven by renewable-grid integration and electric-vehicle supply chains.

For United States Antimony Corporation, these macro trends translate into optionality. By refining high-purity metal domestically, it can supply both defense and commercial sectors, giving it access to higher-margin specialty markets. Partnerships with energy-storage manufacturers could further enhance pricing leverage and secure offtake agreements that stabilize cash flow.

From a policy standpoint, the project aligns with the Biden administration’s broader reshoring and decarbonization objectives. Recent amendments to the Defense Production Act and the Inflation Reduction Act explicitly include antimony among minerals eligible for grant and loan guarantees. This eligibility could make USAC a candidate for low-interest federal financing to accelerate its smelter expansion and exploration drilling on adjacent claims.

Internationally, Western governments are also racing to establish non-Chinese supply chains. Canada and Australia have begun exploration programs, while the European Union has designated antimony as one of its highest-risk critical raw materials. This alignment of global policy focus ensures that UAMY’s Montana operations will continue to attract strategic attention even as production scales gradually.

What the Stibnite Hill restart signals for investors and the broader U.S. resource-security narrative

The relaunch of mining at Stibnite Hill represents more than a local industrial revival — it symbolizes the return of a domestic capability long considered lost. For investors, the development encapsulates a broader shift in market psychology: critical-minerals equities once viewed as speculative are now being reevaluated as instruments of national strategy.

Yet the path ahead is not without hazards. The company must convert early operational momentum into sustained, compliant output. Execution discipline, transparent reporting, and continued cooperation with regulators will determine whether United States Antimony Corporation can transition from a policy-driven story to a consistently profitable producer. If successful, it could serve as a model for how small-cap miners leverage federal alignment to rebuild strategic industries once outsourced abroad.

As the geopolitical competition for resources intensifies, the U.S. government’s focus on antimony — alongside lithium, nickel, and rare earths — underscores an emerging doctrine of mineral sovereignty. United States Antimony Corporation’s restart at Stibnite Hill gives that doctrine a tangible anchor, transforming an overlooked patch of Montana into a potential cornerstone of the American defense and clean-energy supply chain.