American Tungsten Corp. has released an initial Mineral Resource Estimate for the past-producing IMA Mine in Lemhi County, Idaho, establishing an underground tungsten vein system alongside a surface tailings resource on fee-simple land controlled by the company.

The underground tungsten vein system contains 316,000 tonnes of Indicated Mineral Resources grading 0.55% WO₃, holding 1,747 tonnes of WO₃ and 404,000 ounces of silver, alongside 2,178,000 tonnes of Inferred Mineral Resources grading 0.55% WO₃, containing 11,933 tonnes of WO₃ and 1,848,000 ounces of silver.

In addition, American Tungsten defined 267,000 tonnes of Indicated Mineral Resources within surface tailings, grading 0.15% WO₃ and containing 413 tonnes of WO₃ and 79,000 ounces of silver.

The MRE incorporates historical data and over 17,000 feet of drilling completed by American Tungsten since December 2025, contributing to a project dataset exceeding 50,000 feet. Minetech, LLC prepared the estimate under NI 43-101 standards using a cut-off grade of 0.20% WO₃, based on a tungsten price of $1,300 per metric tonne unit, site operating costs of $165 per tonne, and 80% recovery and payability assumptions. Mineral resources are not mineral reserves and lack demonstrated economic viability.

The resource basis incorporates the company’s interpretation of extralateral rights under U.S. mining law, including vein systems that apex on patented claims and extend at depth. While supported by geological studies and historical operations since 1911, these rights have not been adjudicated and remain subject to potential challenge.

The IMA Mine is an underground operation located on 22 patented claims with historical production recorded between 1945 and 1957. To fund ongoing exploration, American Tungsten completed a C$40 million bought deal private placement in March 2026.

“This mineral resource is a transformational milestone for American Tungsten and validates our view that IMA Mine hosts a high-grade tungsten system with meaningful scale and growth potential,” said Ali Haji, Chief Executive Officer of American Tungsten.

— Ali Haji, Chief Executive Officer of American Tungsten

The company plans to file a supporting NI 43-101 Technical Report on SEDAR+ within 45 days of the August 20, 2026 announcement. American Tungsten also intends to advance a Preliminary Economic Assessment to evaluate its phased development strategy, which contemplates processing surface tailings as an initial phase prior to rehabilitating the historic underground mine.

Read the full announcement: American Tungsten Defines High-Grade Tungsten Mineral Resource in the United States at IMA Mine