US Antimony Doubles Its Mining Pace at Stibnite Hill as America Rebuilds a Critical Mineral Supply Chain

United States Antimony Corporation (NYSE, NYSE Texas: UAMY), the only fully integrated antimony producer outside China and Russia, announced on August 25, 2026 that mining operations at its Stibnite Hill property in Thompson Falls, Montana are running at more than double the daily pace of its 2025 campaign. Since resuming mining in April, USAC has transported 42 truckloads, approximately 576 tons of stibnite ore averaging 10% antimony content, at a current rate of roughly three truckloads and 42 tons per operating day. The update lands as the U.S. government leans on USAC to help rebuild a domestic antimony supply chain for defense and critical mineral applications.

Why Antimony Has Become a National Security Priority

Antimony is a critical input in flame retardants, infrared sensors, ammunition primers, and nuclear weapons components, and China has tightened export controls on the metal in recent years as part of broader critical minerals leverage over Western supply chains. That dynamic has pushed antimony from an obscure industrial metalloid into a defense policy priority, and USAC, as the only integrated U.S. producer capable of mining, milling, and smelting antimony domestically, has become a direct beneficiary. The company has committed to supplying $75 million worth of antimony to the U.S. government in 2026, and Montana Public Radio reported that USAC has effectively become “the only game in town” for domestic stockpile replenishment. Reduced dependence on Chinese antimony carries direct relevance to munitions production, night-vision and infrared equipment manufacturing, and other defense-industrial base priorities the Trump administration has emphasized.

A Vertically Integrated Build-Out Backed by Federal Capital

USAC has spent 2026 assembling the infrastructure needed to convert Stibnite Hill’s ore into finished antimony products domestically. The company completed a $4.8 million cash acquisition of a fully operational flotation and concentration facility in Radersburg, Montana in January 2026, giving it in-house midstream processing capacity rather than relying on third-party toll processing. In March 2026, USAC received approval for three project milestones tied to $12.8 million in committed federal funding for its Thompson Falls smelter expansion, with the associated cash proceeds received in April. Ore mined at Stibnite Hill now moves through a fully domestic chain: extraction, trucking to the Radersburg flotation mill, concentration, and final smelting at either Thompson Falls or the company’s Madero, Mexico facility. That vertical integration is central to USAC’s economics, as management has said mining its own ore rather than purchasing third-party material can improve profit margins by roughly three times.

A Guidance Cut Complicates the Volume Story

Today’s mining update extends a trend USAC flagged when it raised full-year 2026 revenue guidance by $25 million to $125 million, citing new antimony source material from Stibnite Hill alongside international procurement already arriving at its Mexican facilities. That guidance has since been withdrawn: on August 11, 2026, alongside second-quarter revenue of $7.9 million and an operating loss of $7.0 million, management cut full-year 2026 revenue guidance to $60 million to $75 million, attributing the revision primarily to a 52% year-over-year decline in realized antimony prices rather than to delivery shortfalls. USAC also holds a 49% interest in a joint venture with Americas Gold and Silver Corporation (which holds 51%) to build an antimony processing facility at the Galena Complex in Idaho’s Silver Valley, where Americas produced approximately 561,000 pounds of antimony contained in concentrate in 2025 as a byproduct of high-grade silver-copper-antimony tetrahedrite ore. Beyond antimony, USAC operates a zeolite business through its Bear River Zeolite subsidiary, serving agricultural, water filtration, and industrial applications, giving the company a secondary revenue stream alongside its core critical minerals push.

Strategic Investment Summary

• Mining Pace Update: US Antimony (NYSE, NYSE Texas: UAMY) reported on August 25, 2026 that Stibnite Hill mining is running at more than double its 2025 daily rate, with 42 truckloads (approximately 576 tons of ore) transported since resuming operations in April.
• Only Integrated U.S. Producer: USAC is the only company outside China and Russia that mines, mills, and smelts antimony domestically, positioning it as a direct beneficiary of U.S. efforts to reduce dependence on Chinese critical mineral supply chains.
• Government Commitment: USAC has committed to supplying $75 million worth of antimony to the U.S. government in 2026, reflecting its expanding role in domestic defense stockpile replenishment.
• Federal Funding Secured: The company received $12.8 million in committed federal funding for its Thompson Falls smelter expansion in March 2026, alongside a $4.8 million cash acquisition of the Radersburg flotation facility completed in January 2026.
• Vertical Integration Economics: Management estimates mining its own antimony ore rather than purchasing third-party material can improve profit margins by approximately three times, underpinning the strategic rationale for the Stibnite Hill ramp.
• Guidance Since Reduced: USAC previously raised full-year 2026 revenue guidance by $25 million to $125 million on the strength of new Stibnite Hill material and international antimony procurement, but cut that outlook to $60 million to $75 million on August 11, 2026 on a 52% decline in realized antimony prices, making the Stibnite Hill ramp a volume story rather than a near-term revenue upgrade.

Find out more about the latest corporate developments and financial reports at the US Antimony investor portal.