Exhibit 5.1

February 24, 2023

Alliance Resources Partners LP

1717 South Boulder Avenue, Suite 400

Tulsa, Oklahoma 74119

Ladies and Gentlemen:

We have acted as counsel for Alliance Resources Partners LP, a Delaware limited partnership (the “Company”), in connection with the Company’s registration under the Securities Act of 1933, as amended (the “Act”), of the offer and sale of an aggregate of up to 8,300,000 units of the Company’s common units, which represent limited partnership interests (the “Units”), pursuant to the Company’s registration statement on Form S-8 (the “Registration Statement”) to be filed with the Securities and Exchange Commission (the “Commission”) on February 24, 2023, which Units may be issued from time to time in accordance with the terms of the Amended and Restated Alliance Coal, LLC 2000 Long-Term Incentive Plan of Alliance Coal, LLC (as amended, the “Plan”).

In reaching the opinions set forth herein, we have examined and are familiar with originals or copies, certified or otherwise identified to our satisfaction, of such documents and records of the Company and such statutes, regulations and other instruments as we deemed necessary or advisable for purposes of this opinion, including (i) the Registration Statement, (ii) certain resolutions adopted by the board of directors of the Company, (iii) the Plan, and (iv) such other certificates, instruments, and documents as we have considered necessary for purposes of this opinion letter. As to any facts material to our opinions, we have made no independent investigation or verification of such facts and have relied, to the extent that we deem such reliance proper, upon certificates of public officials and officers or other representatives of the Company.

We have assumed (i) the legal capacity of all natural persons, (ii) the genuineness of all signatures, (iii) the authority of all persons signing all documents submitted to us on behalf of the parties to such documents, (iv) the authenticity of all documents submitted to us as originals, (v) the conformity to authentic original documents of all documents submitted to us as copies, and (vi) that all information contained in all documents reviewed by us is true, correct and complete. In addition, we have assumed that Units will be issued in accordance with the terms of the Plan.

Based on the foregoing and subject to the limitations set forth herein, and having due regard for the legal considerations we deem relevant, we are of the opinion that the Units have been duly authorized and, when the Units are issued by the Company in accordance with the terms of the Plan and the instruments executed pursuant to the Plan, as applicable, which govern the awards to which any Unit relates, will be validly issued, fully paid (to the extent required by the Company’s partnership agreement) and non-assessable, except as such nonassessability may be limited by Sections 17-303, 17-607 and 17-804 of the Delaware Revised Uniform Limited Partnership Act or within the Company’s partnership agreement.

This opinion is limited in all respects to the Delaware Revised Uniform Limited Partnership Act. We express no opinion as to any matter other than as expressly set forth above, and no opinion on any other matter may be inferred or implied herefrom. The opinions expressed herein are rendered as of the date hereof and we expressly disclaim any obligation to update this letter or advise you of any change in any matter after the date hereof.

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Vinson & Elkins LLP Attorneys at Law

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