US Antimony Furnace Ramp-Up Targets Higher Thompson Falls Output

US Antimony

US Antimony furnace ramp-up is accelerating at the company’s newly commissioned Thompson Falls smelter, with all nine furnaces expected to be operating by the end of June. The expansion is intended to raise domestic antimony processing capacity as US demand remains firm.

US Antimony furnace ramp-up began with the first new furnace starting in May. Five furnaces are expected to be operating by the end of this week, while additional heat exchangers and components are scheduled to arrive in the coming weeks.

US Antimony furnace ramp-up is strategically significant because antimony remains an important input for flame retardants, lead alloys, batteries and defence-related applications. Increasing domestic smelting capacity can reduce exposure to constrained overseas supply chains.

The company has also decided to delay maintenance at its older smelter until 2027, allowing both existing and expanded capacity to contribute more output this year.

Thompson Falls Expansion Raises Domestic Processing Capacity

The Thompson Falls expansion has nameplate capacity of 230 t/month, significantly increasing USAC’s processing potential when fully operational.

The company had previously targeted reaching nearly 80% of that capacity by the end of July. Bringing all nine furnaces online by the end of June suggests the physical ramp-up is progressing faster than that earlier operating milestone implied.

However, commissioning remains dependent on supporting equipment. Delayed delivery of heat exchangers and other components has already affected the project schedule.

The expansion was originally expected to be completed in January. Supplier delays, building construction and other third-party issues pushed the project behind schedule.

These delays illustrate a broader challenge for critical minerals projects. Adding processing capacity often depends on specialised equipment, construction contractors and technical commissioning rather than simply installing furnace shells.

For USAC, the immediate priority is converting installed furnace capacity into reliable sustained production.

Older Smelter Stays Online to Maximise 2026 Antimony Supply

USAC had planned to shut its older 75 t/month smelter for four to eight weeks once the expansion was operating. The maintenance work was intended to bring the facility into compliance with updated emissions requirements.

That shutdown has now been postponed until 2027.

The decision reflects strong product demand and the company’s desire to maximise total production during 2026. Keeping the older unit operating alongside the new furnaces could materially increase near-term output.

This strategy also highlights the value of existing processing assets. In tight specialty metal markets, even older capacity can remain commercially important when new production is still ramping up.

For the US antimony supply chain, the combined operation of both facilities could provide greater short-term resilience.

The longer-term challenge will be maintaining higher production while completing emissions-related upgrades and ensuring stable raw material supply.

The Metalnomist Commentary

USAC’s decision to run both old and new capacity shows how tight antimony supply remains. The key test now is whether Thompson Falls can sustain higher output without creating new bottlenecks in equipment, feedstock or compliance.