Resolution Minerals Produces High-Purity Antimony Trioxide from Idaho Project

Metallurgical test work advances at Antimony Ridge as company progresses U.S.-based processing strategy for critical minerals

Resolution Minerals Ltd (OTCQB:RLMLF)

IDAHO, ID, UNITED STATES, April 13, 2026 /EINPresswire.com/ -- Resolution Minerals Ltd (ASX: RML; OTCQB: RLMLF) is pleased to announce the successful production of high-purity antimony trioxide from its Antimony Ridge project in Idaho, USA, marking a key milestone in advancing domestic supply of a strategically critical mineral.

The antimony trioxide was produced from large samples of stibnite sourced from historical open pits at Antimony Ridge, using conventional pyrometallurgical processing. Initial results returned an intermediate product grading 99.38% antimony trioxide (Sb₂O₃), demonstrating the high-quality nature of the mineralisation and the effectiveness of established processing methods.

Metallurgical test work is ongoing, with further refining of the antimony trioxide product underway and final results expected in the coming weeks. In parallel, Resolution is progressing additional processing pathways, including hydrometallurgical testing at ANSTO in Australia and concentrate optimisation at IMO laboratories in Perth.

The Company is advancing a dual-track development strategy, with conventional pyrometallurgy forming the base-case processing option, while also evaluating hydrometallurgical solutions to support a planned U.S.-based processing hub. This strategy is designed to address the current lack of modern antimony processing infrastructure in the United States.

Adam Roper, PhD, Resolution’s In-house Senior Metallurgist, stated:
“The initial pyrometallurgical results from processing Antimony Ridge samples are very encouraging with few impurities. This is a great start and I’m looking forward to discussing the final results in the coming weeks.

“Resolution’s goal is to develop a processing hub in Idaho for stibnite and I’m relishing the opportunity to bring this to fruition, from mine to product.

“The Johnson Creek Mill site, at the base of Antimony Ridge, is being considered as a fast track option for potential development of a local processing site, given it has the necessary infrastructure on site, with power and water, and is on 10 acres of private land owned 100% by RML.”

Ari Zaetz, RML’s Managing Director, stated:
“With the recent US Government Permitting Council provided via FAST-41 Coverage to accelerate permits, Resolution is in parallel developing further local processing plans to enable antimony and tungsten supply for US demand. Our unique combination of critical minerals assets makes us well placed to deliver.”

Antimony Ridge forms part of Resolution’s broader Horse Heaven Antimony-Tungsten-Gold-Silver Project in Idaho, which has recently been granted FAST-41 Transparency Coverage by the U.S. Permitting Council, highlighting its strategic importance as a potential domestic source of antimony supply.

The project hosts extensive high-grade stibnite mineralisation, with recent results consistently returning antimony grades above 30% and up to 50%. Historical mining at Antimony Ridge dates back to World War I, World War II and the Korean War, when the region was a major supplier of antimony for U.S. military applications.

Recent 3D modelling of the project area has identified multiple antimony- and silver-bearing vein systems across a large footprint, indicating significant scale potential and supporting the Company’s plans for bulk sampling and an extensive drilling program of up to 250 holes.

Resolution is also preparing to commence a major Phase 2 drilling campaign at the Golden Gate Project in May 2026, targeting up to 45,000 feet of diamond drilling to further define gold and tungsten mineralisation within the broader Horse Heaven project area.

Antimony is classified as a critical mineral in the United States due to its essential role in defense systems, energy storage, and industrial applications. Resolution’s strategy to establish an integrated mine-to-processing solution in Idaho positions the Company to contribute to strengthening domestic supply chains for this vital commodity.

About Resolution Minerals Ltd (ASX: RML; OTCQB: RLMLF) is a mineral exploration company currently developing the Horse Heaven Gold-Antimony-Tungsten Project in Idaho, USA with the aim of providing an end-to-end solution for domestic critical minerals supply to US defense industry.

Jane Morgan
Investor and Media Relations
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