EXHIBIT 5.1

September 17, 2025

United States Antimony Corporation

4438 W. Lovers Lane, Unit 100

Dallas, TX 75209

Ladies and Gentlemen:

We have acted as special counsel to United States Antimony Corporation, a Texas corporation (the “Company”), in connection with the preparation and filing of the Registration Statement on Form S-3 (File No. 333-284057) (as amended or supplemented, the “Registration Statement”) filed with the Securities and Exchange Commission (the “Commission”) pursuant to the Securities Act of 1933, as amended (the “Securities Act”), relating to the registration of the offering by the Company of up to $100,000,000 of any combination of securities of the types specified therein. The Registration Statement was declared effective by the Commission on April 24, 2025. We are delivering this opinion letter in connection with the prospectus supplement (the “Prospectus”) filed on September 17, 2025 by the Company pursuant to Rule 424(b) under the Securities Act, which replaces, updates, amends and supplements the prospectus supplement to the Registration Statement, dated April 24, 2025. The Prospectus relates to the offering by the Company of up to $65,000,000 in aggregate of shares (the “Shares”) of the Company’s common stock, par value $0.01 per share, covered by the Registration Statement. The Shares are being offered and sold by the sales agents named in, and pursuant to, that certain Sales Agreement, dated November 12, 2024, as amended and restated on September 17, 2025 (the “Agreement”), among the Company and the sales agents named therein. This opinion is being rendered in accordance with the requirements of Item 601(b)(5) of Regulation S-K under the Securities Act.

For purposes of rendering this opinion, we have examined originals or copies (certified or otherwise identified to our satisfaction) of (i) the Registration Statement, (ii) the Prospectus, (iii) the Agreement, (iv) the Company’s Certificate of Formation and Bylaws, (v) certain resolutions of the Company’s Board of Directors approving the Registration Statement, the Prospectus, and the issuance of the Shares pursuant to the Agreement and (vi) such corporate records, agreements, documents and other instruments, and such certificates or comparable documents of public officials and of officers and representatives of the Company, and have made such inquiries of such officers and representatives, as we have deemed relevant and necessary as a basis for the opinions hereinafter set forth.

United States Antimony Corporation 

September 17, 2025

Page 2

In such examination, we have assumed (i) the genuineness of all signatures, (ii) the legal capacity and competency of all natural persons, (iii) the authenticity of all documents submitted to us as originals, (iv) the conformity to original documents of all documents submitted to us as facsimile, electronic, certified, conformed or other copies and the authenticity of the originals of such documents, (v) that all records and other information made available to us by the Company on which we have relied are true, accurate and complete in all material respects, (vi) that each person signing in a representative capacity (other than on behalf of the Company) any document reviewed by us had authority to sign in such capacity, (vii) that the Registration Statement, and any amendments thereto (including, as applicable, all necessary post-effective amendments thereto), will remain effective under the Securities Act and comply with all applicable laws, (viii) that all Shares will be sold in compliance with federal and state securities laws and in the manner stated in the Registration Statement or any amendment thereto (including post-effective amendments) and the Prospectus, and that all applicable provisions of the securities laws of the various jurisdictions in which the Shares may be offered and sold will have been complied with, and (ix) that each certificate from governmental officials reviewed by us is accurate, complete and authentic, and all official public records are accurate and complete.

As to all questions of fact material to these opinions, we have relied solely upon the above-referenced certificates or comparable documents and have not performed or had performed any independent research or investigation of public records as to the facts set forth therein and have assumed that certificates of or other comparable documents from public officials dated prior to the date hereof remain accurate as of the date hereof.

Based on the foregoing, and subject to the limitations, assumptions and qualifications set forth herein, we are of the opinion that the Shares, when issued and delivered by the Company in accordance with the terms of the Agreement and upon receipt by the Company of the consideration therefor as provided therein, will be validly issued, fully paid and nonassessable.

The opinions expressed herein are limited to the Texas Business Organizations Code (collectively, the “Applicable Laws”). No opinion is expressed as to the effect on the matters covered by this letter of the laws of (i) the State of Texas other than the Applicable Laws or (ii) any jurisdiction other than the State of Texas, whether in any such case applicable directly or through the Applicable Laws. We express no opinion regarding any federal or state securities laws or regulations or as to whether, or the extent to which, the laws of any particular jurisdiction apply to the subject matter hereof.

The opinions expressed herein are rendered as of the date hereof and are based on existing law, which is subject to change. Where our opinions expressed herein refer to events to occur at a future date, we have assumed that there will have been no changes in the relevant law or facts between the date hereof and such future date. We do not undertake to advise you of any changes in the opinions expressed herein from matters that may hereafter arise or be brought to our attention or to revise or supplement such opinions should the present laws of any jurisdiction be changed by legislative action, judicial decision or otherwise. These opinions are expressed as of the date hereof unless otherwise expressly stated, and we disclaim any undertaking to advise you of any subsequent changes in the facts stated or assumed herein or of any subsequent changes in applicable laws.

United States Antimony Corporation

September 17, 2025

Page 3

Our opinions expressed herein are limited to the matters expressly stated herein and no opinion is implied or may be inferred beyond the matters expressly stated.

This letter may be relied upon by the Company and by persons entitled to rely upon it pursuant to the applicable provisions of the Securities Act and cannot be relied upon for any other purpose. We hereby consent to the use of this letter as an exhibit to the Registration Statement and to any and all references to our firm under the heading “Legal Matters” in the Prospectus. In giving this consent, we do not imply or admit that we are within the category of persons whose consent is required under Section 7 of the Securities Act or the rules and regulations of the Commission promulgated thereunder.

 

	Very truly yours,
	/s/ Duane Morris LLP