United States Antimony restarts mining in Montana

United States Antimony (NYSE: UAMY) said Thursday milder temperatures and snowfall than expected allowed it to resume mining at its Stibnite Hill property in Montana after an almost five-month halt.

In November, the company said it had stopped work due to weather, just weeks after beginning to mine raw ore from Stibnite Hill for test processing at a flotation facility in Radersburg, about 55 km southeast of state capital Helena, following Montana state approval.

The plan is to process the material into antimony concentrates. Those will be shipped to the company’s smelter in Thompson Falls in northwestern Montana, about 190 km west-northwest of Helena, for making finished products sold to customers.

Shares of United States Antimony advanced 5.6% on Thursday afternoon, more than erasing its losses for the week. The company, which recently uplisted to the NYSE, has a market capitalization of $1.26 billion.

Defence metal

Antimony has several key industrial uses, among which are defence applications such as flame retardant fabrics, communication equipment, night vision goggles, ammunition hardening and laser sighting. The U.S. has no mined production of antimony, and therefore relies on foreign suppliers such as China for the critical mineral that its military uses.

The Thompson Falls plant is currently the only antimony smelter in the U.S. The company also holds the only other smelter in North America: the Madero smelter in Mexico.

With the start of operations at Stibnite Hill — a former mine that operated for 15 years from the late 1960s to early 80s — the company is looking to establish itself as the only fully integrated antimony operation outside of China and Russia.

United States Antimony says its Thompson Falls smelter can produce about 15 million lb. of antimony oxide or 5 million lb. of antimony metal per year. It’s expanding the plant to boost that production capacity.

Mining program

During last year’s mining period, some 800 tons (726 tonnes) of antimony ore were brought from the mountain to the Radersburg facility, the company has noted. The material could be upgraded to meet military specifications, the company said back in October.

This year, the company plans to place GPS transmitters at stations on adjacent mountain tops. Field crews will be able to use portable data collectors for more accurate mapping and recording of antimony vein intercepts, enabling the projection of antimony veins on strike and down dip.

It’s also using a chipper for smaller brush and branches to produce a mulch for a reclamation program. It aims to quicken vegetation re-growth while providing better access to existing roads and trails where 2026 mining activities are commencing, it said.