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Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 FORM 10 - K ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE FISCAL YEAR ENDED DECEMBER 31 , 2020 OR □ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 TO FOR THE TRANSITION PERIOD FROM COMMISSION FILE NO .: 0-26823 ALLIANCE RESOURCE PARTNERS , L.P. ( EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER ) 73-1564280 Delaware ( State or Other Jurisdiction of Incorporation or Organization ) Title of Each Class Common Units representing limited partner interests 1717 South Boulder Avenue , Suite 400 , Tulsa , Oklahoma 74119 ( Address of Principal Executive Offices and Zip Code ) ( 918 ) 295-7600 ( Registrant's Telephone Number , Including Area Code ) Securities registered pursuant to Section 12 ( b ) of the Act : Trading Symbol ARLP Securities registered pursuant to Section 12 ( g ) of the Act : None ( IRS Employer Identification No. ) Indicate by check mark if the registrant is a well - known seasoned issuer , as defined in Rule 405 of the Securities Act . Yes No Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15 ( d ) of the Act . Yes No Name of Each Exchange On Which Registered The NASDAQ Stock Market LLC Indicate by check mark whether the registrant ( 1 ) has filed all reports required to be filed by Section 13 or 15 ( d ) of the Securities Exchange Act of 1934 during the preceding 12 months ( or for such shorter period that the registrant was required to file such reports ) , and ( 2 ) has been subject to such filing requirements for the past 90 days . Yes No Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S - T ( §232.405 of this chapter ) during the preceding 12 months ( or for such shorter period that the registrant was required to submit such files ) . < Yes No Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S - K is not contained herein , and will not be contained , to the best of registrant's knowledge , in definitive proxy or information statements incorporated by reference in Part III of this Form 10 - K or any amendment to this Form 10 - K . > Accelerated Filer > Indicate by check mark whether the registrant is a large accelerated filer , an accelerated filer , a non - accelerated filer , a smaller reporting company , or an emerging growth company . See the definitions of " large accelerated filer , " " accelerated filer , " " smaller reporting company " and " emerging growth company " in Rule 12b - 2 of the Exchange Act . Large Accelerated Filer Non - Accelerated Filer ( Do not check if smaller reporting company ) Smaller Reporting Company As of February 23 , 2021 , 127,195,219 common units were outstanding . DOCUMENTS INCORPORATED BY REFERENCE : None Emerging Growth Company If an emerging growth company , indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13 ( a ) of the Exchange Act . Indicate by check mark whether the registrant has filed a report on and attestation to its management's assessment of the effectiveness of its internal control over financial reporting under Section 404 ( b ) of the Sarbanes - Oxley Act ( 15 U.S.C. 726 ( b ) ) by the registered public accounting firm that prepared or issued its audit report . Indicate by check mark whether the registrant is a shell company ( as defined in Rule 12b - 2 of the Exchange Act ) . Yes - No The aggregate value of the common units held by non - affiliates of the registrant ( treating all executive officers and directors of the registrant , for this purpose , as if they may be affiliates of the registrant ) was approximately $ 343,214,355 as of June 30 , 2020 , the last business day of the registrant's most recently completed second fiscal quarter , based on the reported closing price of the common units as reported on The NASDAQ Stock Market LLC on such date .