EXHIBIT 21.1

Subsidiaries of Registrant as of December 31, 2025

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Name | ​ ​ ​ | Jurisdiction
Bear River Zeolite Company | ​ | Idaho
Antimonio de Mexico, S.A. de C.V. | ​ | Mexico
US Antimony de Mexico, S.A. de C.V. | ​ | Mexico
Stibnite Holding Company US Inc. | ​ | Montana
Antimony Mining and Milling US LLC | ​ | Montana
AGAU Mines, Inc. | ​ | Montana
Lanxess Laurel de Mexico, S.A. de C.V. | ​ | Mexico
Great Land Minerals, LLC | ​ | Delaware
Denali Minerals, LLC | ​ | Delaware
Alaska Antimony LLC | ​ | Alaska
UAMY Cobalt Corporation | ​ | Ontario, Canada
TFRE Holdings LLC | ​ | Montana
TFPROP LLC | ​ | Montana

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