US Antimony Moves 42 Tons a Day Off Stibnite Hill

United States Antimony (NYSE American: UAMY) said it has more than doubled the daily extraction rate at its Stibnite Hill mine near Thompson Falls, Montana, to 42 tons of ore per day, with 576 tons of high-grade stibnite ore mined since operations resumed in April.

United States Antimony Corp. (NYSE American: UAMY) says it is now pulling 42 tons of ore a day out of Stibnite Hill in western Montana, more than double the pace of last year's short mining campaign. The company frames the gain not as a geological surprise but as a logistics one: three truckloads a day are coming off the mountain, and the trucks are the constraint that matters.

Since work restarted at the property in April, after the winter shutdown, US Antimony has extracted 576 tons of high-grade stibnite ore. Stibnite is antimony sulfide, the principal ore mineral for antimony, and the company puts the grade of the hauled material at roughly 10 percent antimony. Forty-two truckloads have moved so far, averaging 14 tons each.

What the numbers say about the pace change

The comparison point is the 2025 campaign, when the company moved 800 tons over a 45-day window before November weather closed the mountain. Averaged across those days, that works out to roughly 17.8 tons a day — so the current 42-ton rate is about 2.4 times last year's pace on an illustrative like-for-like basis. Those two figures are the ones management is implicitly netting when it talks about moving rock "twice as fast."

"We continue to improve our operations on Stibnite Hill by moving rock off the mountain over twice as fast as we did last year," EVP and Chief Mining Engineer Joseph Bardswich said in the announcement, reported by INN Precious Metals. "Our contractors are becoming more efficient."

Contractor efficiency is the operative phrase. Stibnite Hill is not a large-scale mechanized operation feeding a conveyor; it is a narrow, high-grade deposit being worked and trucked. When the bottleneck is haulage cycles rather than the rock face, gains come from scheduling, road condition and driver hours — cheap improvements relative to buying new equipment. That is a useful characteristic for a company at this stage: the throughput went up without a headline capital number attached to it.

Applying the stated 10 percent grade to the 576 tons hauled implies on the order of 58 tons of contained antimony mined since April. That is an illustrative calculation, not a company disclosure, and it describes metal in ore rather than metal recovered — flotation and smelting losses sit between the two.

The chain from mountain to finished product

What separates US Antimony from a typical junior developer is that the material has somewhere to go. Ore from Stibnite Hill is trucked to the company's flotation mill at Radersburg, Montana, where the stibnite is upgraded into a concentrate. The concentrate then moves to one of two smelters the company controls: Thompson Falls, Montana, or Madero, Mexico, where it is processed into finished antimony products.

Owning mill and smelter capacity changes the arithmetic of a small mining operation. A developer with 576 tons of high-grade ore and no processing route has an inventory problem. A company with its own flotation circuit and smelters has a feedstock question instead — how much of the plant's capacity domestic ore can fill, versus purchased or imported material. Every additional ton off Stibnite Hill is a ton that does not have to be sourced from a third party, and the trucking distance from Radersburg to Thompson Falls is measured in hours, not ocean freight weeks.

That vertical structure is also why the daily extraction rate is a more meaningful metric here than it would be for a pure explorer. It maps directly onto smelter feed rather than onto a future feasibility study.

Why antimony supply has Washington's attention

Antimony sits on the US critical minerals list, and for reasons that are not subtle. It goes into flame retardants, lead-acid battery alloys, ammunition primers, and hardening agents in military applications — and domestic production has been minimal for decades, with refining concentrated overseas. Any tonnage that can be mined, milled and smelted entirely inside the United States carries strategic weight out of proportion to its size.

That is the backdrop against which a jump from three truckloads a day gets a press release. US Antimony is one of a very short list of companies with an operating antimony smelter on US soil. The Madero facility in Mexico adds capacity but sits across a border, which in the current trade environment is a variable rather than a constant. The Thompson Falls smelter, fed by Montana ore through a Montana mill, is the part of the chain that looks cleanest to a defense or industrial buyer writing a domestic-content requirement into a contract.

The stock, and the seasonal clock

UAMY finished the most recent session at 5.20, up 1.96% on the day, having traded between 5.04 and 5.27 against a previous close of 5.10. It outpaced the broad market: the S&P 500 tracker closed at $765.91, up 0.32%, the Nasdaq 100 proxy at $710.72, up 0.62%, and the Dow tracker at $535.24, up 0.30%, all as of the last trade at 20:00 GMT on Aug. 25, 2026. Markets are closed; those are last prices, not live ones.

The more important calendar for this operation is not the trading week but the season. Last year's campaign ended in November when winter weather stopped work, and the mine did not restart until April. That is a mining window of roughly seven months if the same pattern holds — meaning the current 42-ton-per-day rate has a finite runway before the mountain closes again. Investors watching this story should be counting the weeks of haulage left as much as the tons per day.

What to watch from here

• Whether the 42-ton daily rate is sustained or was a peak-week figure, and whether truckloads per day rise beyond three.
• Grade consistency — the roughly 10 percent antimony content is what makes small tonnages economically interesting. A drop in grade would blunt the throughput gain.
• How much of Radersburg's mill capacity and the Thompson Falls smelter's feed the Stibnite Hill ore actually covers.
• The date work stops for winter this year, compared with last November, as a measure of how much operational slack the contractors have found.
• Any disclosure tying domestic antimony output to government or defense-linked offtake, which is where the strategic premium would show up in revenue rather than in rhetoric.

None of this makes Stibnite Hill a large mine. Doubling a small number leaves a small number. But the company has demonstrated something narrower and more useful than scale: that it can move high-grade domestic antimony ore from a Montana hillside into a US smelter, faster this year than last, without waiting for a permit or a plant to be built.

Key facts

• UAMY last close: 5.20, +1.96% (as of Aug. 25, 2026, 20:00 GMT)
• Daily extraction rate: 42 tons of ore per day, three truckloads
• Ore mined since April: 576 tons at approximately 10% antimony
• 2025 comparison: 800 tons over 45 days before November shutdown

Frequently asked questions

How much ore is US Antimony now mining at Stibnite Hill?

The company says the Stibnite Hill mine near Thompson Falls, Montana, is producing 42 tons of ore per day, equivalent to three truckloads. Since operations resumed in April following the winter shutdown, 576 tons of high-grade stibnite ore have been extracted across 42 truckloads averaging 14 tons each.

What grade is the ore?

US Antimony puts the antimony content of the hauled material at approximately 10 percent. The ore mineral is stibnite, or antimony sulfide, which is the principal commercial source of antimony worldwide. Grade consistency matters more than tonnage at this scale, because high grade is what makes small volumes economically worthwhile.

Where does the ore go after it leaves the mine?

Material is trucked to the company's flotation mill at Radersburg, Montana, where it is upgraded into antimony concentrate. That concentrate is then shipped to one of two US Antimony smelters — Thompson Falls in Montana or Madero in Mexico — to be processed into finished antimony products.

How does this compare with last year's production?

During the 2025 campaign, the company moved 800 tons over a 45-day period before winter weather halted work in November. Averaged across that window, that is roughly 17.8 tons a day, so the current 42-ton rate represents about 2.4 times last year's pace on an illustrative basis.

Why is antimony considered a critical mineral?

Antimony is used in flame retardants, lead-acid battery alloys, ammunition primers and as a hardening agent in military applications. US domestic mining and refining capacity has been limited for decades, with processing concentrated overseas, which is why tonnage mined, milled and smelted entirely within the United States carries strategic significance.

Where did UAMY shares last trade?

United States Antimony closed at 5.20, up 1.96% from a previous close of 5.10, with a session range of 5.04 to 5.27, as of the last trade at 20:00 GMT on Aug. 25, 2026. That outpaced the broad market, where the S&P 500 tracker gained 0.32% and the Nasdaq 100 proxy 0.62%.

Sources

• US Antimony Doubles Ore Extraction at Stibnite Hill — INN Precious Metals

Photo: Robert So · Pexels Licence — source