Alliance Resource Partners (ARLP) 10-Q 7 Nov 24 2024 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2024	Nov. 07, 2024
Document and Entity Information
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Sep. 30, 2024
Securities Act File Number	0-26823
Entity Registrant Name	ALLIANCE RESOURCE PARTNERS LP
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	73-1564280
Entity Address, Address Line One	1717 South Boulder Avenue, Suite 400
Entity Address, City or Town	Tulsa
Entity Address, State or Province	OK
Entity Address, Postal Zip Code	74119
City Area Code	918
Local Phone Number	295-7600
Title of 12(b) Security	Common units
Trading Symbol	ARLP
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Units Outstanding		128,061,981
Entity Central Index Key	0001086600
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q3
Amendment Flag	false

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
CURRENT ASSETS:
Cash and cash equivalents	$ 195,429	$ 59,813
Trade receivables	198,647	282,622
Other receivables	10,015	9,678
Inventories, net	177,503	127,556
Advance royalties	6,170	7,780
Digital assets	28,959	9,579
Prepaid expenses and other assets	9,785	19,093
Total current assets	626,508	516,121
PROPERTY, PLANT AND EQUIPMENT:
Property, plant and equipment, at cost	4,451,796	4,172,544
Less accumulated depreciation, depletion and amortization	(2,290,205)	(2,149,881)
Total property, plant and equipment, net	2,161,591	2,022,663
OTHER ASSETS:
Advance royalties	76,295	71,125
Equity method investments	36,902	46,503
Equity securities	92,541	92,541
Operating lease right-of-use assets	16,092	16,569
Other long-term assets	22,244	22,904
Total other assets	244,074	249,642
TOTAL ASSETS	3,032,173	2,788,426
CURRENT LIABILITIES:
Accounts payable	115,719	108,269
Accrued taxes other than income taxes	21,336	21,007
Accrued payroll and related expenses	32,733	29,884
Accrued interest	10,637	3,558
Workers' compensation and pneumoconiosis benefits	15,790	15,913
Other current liabilities	46,662	28,498
Current maturities, long-term debt, net	22,275	20,338
Total current liabilities	265,152	227,467
LONG-TERM LIABILITIES:
Long-term debt, excluding current maturities, net	456,316	316,821
Pneumoconiosis benefits	131,727	127,249
Accrued pension benefit	7,005	8,618
Workers' compensation	36,981	37,257
Asset retirement obligations	148,849	146,925
Long-term operating lease obligations	13,838	13,661
Deferred income tax liabilities	32,019	33,450
Other liabilities	15,176	18,381
Total long-term liabilities	841,911	702,362
Total liabilities	1,107,063	929,829
COMMITMENTS AND CONTINGENCIES - (NOTE 4)
ARLP Partners' Capital:
Limited Partners - Common Unitholders 128,061,981 and 127,125,437 units outstanding, respectively	1,961,977	1,896,027
Accumulated other comprehensive loss	(58,623)	(61,525)
Total ARLP Partners' Capital	1,903,354	1,834,502
Noncontrolling interest	21,756	24,095
Total Partners' Capital	1,925,110	1,858,597
TOTAL LIABILITIES AND PARTNERS' CAPITAL	$ 3,032,173	$ 2,788,426

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - shares	Sep. 30, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Common units outstanding	128,061,981	127,125,437

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
SALES AND OPERATING REVENUES:
Revenues	$ 613,569	$ 636,521	$ 1,858,616	$ 1,941,279
EXPENSES:
Outside coal purchases	8,192	11,530	27,912	15,739
General and administrative	21,878	20,097	64,569	61,312
Depreciation, depletion and amortization	72,971	65,393	204,974	199,582
Total operating expenses	512,502	471,083	1,479,834	1,384,586
INCOME FROM OPERATIONS	101,067	165,438	378,782	556,693
Interest expense	(9,527)	(7,736)	(26,553)	(29,845)
Interest income	2,175	2,669	5,535	8,084
Equity method investment loss	(2,327)	(1,842)	(3,032)	(3,784)
Change in fair value of digital assets	332		8,437
Other income (expense)	(681)	223	(2,245)	(173)
INCOME BEFORE INCOME TAXES	91,039	158,752	360,924	530,975
INCOME TAX EXPENSE	4,123	3,401	12,932	11,641
NET INCOME	86,916	155,351	347,992	519,334
LESS: NET INCOME ATTRIBUTABLE TO NONCONTROLLING INTEREST	(635)	(1,652)	(3,467)	(4,660)
NET INCOME ATTRIBUTABLE TO ARLP	86,281	153,699	344,525	514,674
NET INCOME ATTRIBUTABLE TO ARLP
GENERAL PARTNER				1,384
LIMITED PARTNERS	$ 86,281	$ 153,699	$ 344,525	$ 513,290
EARNINGS PER LIMITED PARTNER UNIT - BASIC (in dollars per unit)	$ 0.66	$ 1.18	$ 2.64	$ 3.93
EARNINGS PER LIMITED PARTNER UNIT - DILUTED (in dollars per unit)	$ 0.66	$ 1.18	$ 2.64	$ 3.93
WEIGHTED-AVERAGE NUMBER OF UNITS OUTSTANDING - BASIC (in units)	128,061,981	127,125,437	127,932,095	127,198,805
WEIGHTED-AVERAGE NUMBER OF UNITS OUTSTANDING - DILUTED (in units)	128,062,000	127,125,000	127,932,000	127,199,000
Product
EXPENSES:
Operating expenses (excluding depreciation, depletion and amortization)	$ 384,844	$ 339,099	$ 1,100,308	$ 1,012,224
Coal sales
SALES AND OPERATING REVENUES:
Revenues	532,647	549,123	1,607,185	1,688,238
Oil & gas royalties
SALES AND OPERATING REVENUES:
Revenues	34,448	34,125	107,907	101,709
Transportation
SALES AND OPERATING REVENUES:
Revenues	24,617	34,964	82,071	95,729
EXPENSES:
Operating expenses (excluding depreciation, depletion and amortization)	24,617	34,964	82,071	95,729
Other revenues
SALES AND OPERATING REVENUES:
Revenues	$ 21,857	$ 18,309	$ 61,453	$ 55,603

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
CONDENSED CONSOLIDATED STATEMENTS OF INCOME
Interest expense, interest capitalized	$ 3,521	$ 1,809	$ 8,605	$ 4,432

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
NET INCOME	$ 86,916	$ 155,351	$ 347,992	$ 519,334
OTHER COMPREHENSIVE INCOME:
OTHER COMPREHENSIVE INCOME	1,022	561	2,902	1,689
COMPREHENSIVE INCOME	87,938	155,912	350,894	521,023
Less: Comprehensive income attributable to noncontrolling interest	(635)	(1,652)	(3,467)	(4,660)
COMPREHENSIVE INCOME ATTRIBUTABLE TO ARLP	87,303	154,260	347,427	516,363
Defined benefit pension plan
OTHER COMPREHENSIVE INCOME:
Amortization of prior service cost	47	47	140	140
Amortization of net actuarial loss	136	169	245	513
Total recognized in accumulated other comprehensive Income	183	216	385	653
Pneumoconiosis benefits
OTHER COMPREHENSIVE INCOME:
Amortization of net actuarial loss	839	345	2,517	1,036
Total recognized in accumulated other comprehensive Income	$ 839	$ 345	$ 2,517	$ 1,036

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
CASH FLOWS FROM OPERATING ACTIVITIES:
CASH FLOWS FROM OPERATING ACTIVITIES	$ 634,711	$ 730,298
Property, plant and equipment:
Capital expenditures	(335,586)	(295,356)
Change in accounts payable and accrued liabilities	9,191	(23,006)
Proceeds from sale of property, plant and equipment	1,385	3,436
Contributions to equity method investments	(1,398)	(2,257)
Purchase of equity securities		(49,560)
JC Resources acquisition		(64,999)
Oil & gas reserve asset acquisitions	(15,176)	(13,902)
Other	4,151	6,273
Net cash used in investing activities	(337,433)	(439,371)
CASH FLOWS FROM FINANCING ACTIVITIES:
Borrowings under securitization facility	75,000
Payments under securitization facility	(75,000)
Proceeds from equipment financings	54,626
Payments on equipment financings	(8,926)	(11,421)
Borrowings under revolving credit facilities	20,000
Payments under revolving credit facilities	(20,000)
Borrowing under long-term debt	400,000	75,000
Payments on long-term debt	(296,327)	(120,080)
Payment of debt issuance costs	(11,442)	(11,744)
Payments for purchases of units under unit repurchase program		(19,432)
Payments for tax withholdings related to settlements under deferred compensation plans	(15,544)	(10,334)
Excess purchase price over the contributed basis from JC Resources acquisition		(7,251)
Cash retained by JC Resources in acquisition		(2,933)
Distributions paid to Partners	(272,707)	(273,767)	$ (364,579)
Other	(11,342)	(7,745)
Net cash used in financing activities	(161,662)	(389,707)
NET CHANGE IN CASH AND CASH EQUIVALENTS	135,616	(98,780)
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	59,813	296,023	296,023
CASH AND CASH EQUIVALENTS AT END OF PERIOD	195,429	197,243	$ 59,813
SUPPLEMENTAL CASH FLOW INFORMATION:
Cash paid for interest	24,263	22,411
Cash paid for income taxes	16,509	10,420
SUPPLEMENTAL NON-CASH ACTIVITY:
Accounts payable for purchase of property, plant and equipment	23,777	21,275
Right-of-use assets acquired by operating lease	716	2,596
Market value of common units issued under deferred compensation plans before tax withholding requirements	$ 34,880	$ 28,906

ORGANIZATION AND PRESENTATION

ORGANIZATION AND PRESENTATION	9 Months Ended
	Sep. 30, 2024
ORGANIZATION AND PRESENTATION
ORGANIZATION AND PRESENTATION	1. ORGANIZATION AND PRESENTATION ​ Significant Relationships Referenced in Notes to Condensed Consolidated Financial Statements ​ ● References to "we," "us," "our" or "ARLP Partnership" mean the business and operations of Alliance Resource Partners, L.P., the parent company, as well as its consolidated subsidiaries. ● References to "ARLP" mean Alliance Resource Partners, L.P., individually as the parent company, and not on a consolidated basis. ● References to "MGP" mean Alliance Resource Management GP, LLC, ARLP's general partner. ● References to "Intermediate Partnership" mean Alliance Resource Operating Partners, L.P., the intermediate partnership of Alliance Resource Partners, L.P. ● References to "Alliance Coal" mean Alliance Coal, LLC, an indirect wholly owned subsidiary of ARLP. ● References to "Alliance Minerals" mean Alliance Minerals, LLC, an indirect wholly owned subsidiary of ARLP. ● References to "Alliance Resource Properties" mean Alliance Resource Properties, LLC, an indirect wholly owned subsidiary of ARLP. ​ Organization ​ ARLP is a Delaware limited partnership listed on the NASDAQ Global Select Market under the ticker symbol "ARLP." ARLP was formed in May 1999 and completed its initial public offering on August 19, 1999 when it acquired substantially all of the coal production and marketing assets of Alliance Resource Holdings, Inc., a Delaware corporation, and its subsidiaries. We are managed by our general partner, MGP, a Delaware limited liability company which holds a non-economic general partner interest in ARLP. ​ Basis of Presentation ​ The accompanying condensed consolidated financial statements include the accounts and operations of the ARLP Partnership and present our financial position as of September 30, 2024 and December 31, 2023, the results of our operations and comprehensive income for the three and nine months ended September 30, 2024 and 2023 and cash flows for the nine months ended September 30, 2024 and 2023. All intercompany transactions and accounts have been eliminated. Certain immaterial amounts in the prior period have been reclassified to conform to the current period presentation. ​ These condensed consolidated financial statements and notes are prepared pursuant to the rules and regulations of the Securities and Exchange Commission for interim reporting and do not include all the information normally included with financial statements prepared in accordance with generally accepted accounting principles ("GAAP") of the United States. These financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2023. ​ These condensed consolidated financial statements and notes are unaudited. However, in the opinion of management, these condensed consolidated financial statements reflect all normal recurring adjustments necessary for a fair presentation of the results for the periods presented. Results for interim periods are not necessarily indicative of results to be expected for the full year ending December 31, 2024. ​ Use of Estimates ​ The preparation of the ARLP Partnership's condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts and disclosures in our condensed consolidated financial statements. Actual results could differ from those estimates. ​ Digital Assets ​ We began our crypto-mining activities during the second half of 2020 as we started mining bitcoin as a pilot project to monetize already paid for, yet underutilized, electricity load. We continue to periodically be awarded digital assets through our crypto-mining activities. The awards are accounted for as revenue and valued at the exchange quoted price at the time they are awarded. Beginning January 1, 2024, with our adoption of the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2023-08, Intangibles - Goodwill and Other - Crypto Assets (Subtopic 350-60) Digital assets Change in fair value of digital assets

NEW ACCOUNTING STANDARDS

NEW ACCOUNTING STANDARDS	9 Months Ended
	Sep. 30, 2024
NEW ACCOUNTING STANDARDS
NEW ACCOUNTING STANDARDS	2. NEW ACCOUNTING STANDARDS ​ New Accounting Standards Issued and Adopted ​ In December 2023, the FASB issued ASU 2023-08, Intangibles - Goodwill and Other - Crypto Assets (Subtopic 350-60) ​ New Accounting Standards Issued and Not Yet Adopted ​ In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures ​ In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures

ACQUISITIONS

ACQUISITIONS	9 Months Ended
	Sep. 30, 2024
ACQUISITIONS
ACQUISITIONS	3. ACQUISITION S ​ Acquisition Agreement ​ On January 27, 2023, we entered into a one-year collaborative agreement with a third party, effective January 1, 2023, committing up to $35.0 million for the acquisition of oil & gas mineral interests in the Midland and Delaware Basins. On February 19, 2024, we renewed this agreement for an additional one-year term, committing up to $25.0 million. Under the agreement, the third party assists us in the identification, evaluation, and acquisition of target oil & gas mineral interests. In exchange for these services, the third party receives a participation share, partially funded by the third party, and is paid a periodic management fee. During the nine months ended September 30, 2024, we purchased $5.1 million and $7.8 million of oil & gas mineral interests in proved and unproved properties, respectively, pursuant to this agreement. Management fees ​ Miscellaneous Acquisitions ​ In addition to the acquisitions under the collaborative agreement discussed above, we purchased $0.7 million and $1.6 million of oil & gas mineral interests in proved and unproved properties, respectively, during the nine months ended September 30, 2024. ​

CONTINGENCIES

CONTINGENCIES	9 Months Ended
	Sep. 30, 2024
CONTINGENCIES
CONTINGENCIES	4. CONTINGENCIES ​ Certain of our subsidiaries are party to litigation in which the plaintiffs allege violations of the Fair Labor Standards Act and state law due to alleged failure to compensate for time "donning" and "doffing" equipment and to account for certain bonuses in the calculation of overtime rates and pay. In April 2024, we entered into a settlement agreement with the plaintiffs pursuant to which we agreed to settle such litigation for $15.3 million. As a result of reaching this settlement, which is subject to court approval, we have accrued $15.3 million as of September 30, 2024. Our $15.3 million accrual is included in the Other current liabilities ​ We also have various other lawsuits, claims and regulatory proceedings incidental to our business that are pending against the ARLP Partnership. We record an accrual for a potential loss related to these matters when, in management's opinion, such loss is probable and reasonably estimable. Based on known facts and circumstances, we believe the ultimate outcome of these outstanding lawsuits, claims and regulatory proceedings will not have a material adverse effect on our financial condition, results of operations or liquidity. However, if the results of these matters are different from management's current expectations and in amounts greater than our accruals (if any), such matters could have a material adverse effect on our business and operations.

INVENTORIES

INVENTORIES	9 Months Ended
	Sep. 30, 2024
INVENTORIES
INVENTORIES	5. INVENTORIES ​ Inventories consist of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ ​ ​ 2024 2023 ​ ​ (in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ Coal ​ $ 95,333 ​ $ 56,549 ​ Finished goods (net of reserve for obsolescence of $723 and $728, respectively) ​ ​ 3,812 ​ ​ 3,908 ​ Work in process ​ ​ 580 ​ ​ 791 ​ Raw materials ​ ​ 1,838 ​ ​ 2,144 ​ ​ ​ ​ 101,563 ​ ​ 63,392 ​ Supplies (net of reserve for obsolescence of $8,036 and $7,439, respectively) ​ 75,940 ​ 64,164 ​ Total inventories, net ​ $ 177,503 ​ $ 127,556 ​ ​ ​ Certain of our subsidiaries, primarily consisting of Matrix Design Group, LLC, its subsidiaries, and Alliance Design Group, LLC (collectively referred to as "Matrix Group"), manufacture a variety of products for our mining operations and third parties. These products are primarily consumed internally by our mining operations with associated inventory historically presented as supplies inventory. Recently Matrix Group has been increasing its production of products with the intention to increase third-party sales. We have therefore presented our manufactured goods inventories in the table above separately from our historical presentation of supplies inventory.

DIGITAL ASSETS

DIGITAL ASSETS	9 Months Ended
	Sep. 30, 2024
DIGITAL ASSETS
DIGITAL ASSETS	6. DIGITAL ASSETS ​ The following table sets forth our digital assets as shown on the condensed consolidated balance sheet: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2024 ​ ​ ​ Units ​ Cost Basis ​ Fair Value ​ Digital assets: ​ (in thousands, except unit data) ​ Bitcoin ​ ​ 457.24 ​ $ 16,327 ​ $ 28,959 ​ Total ​ ​ ​ ​ $ 16,327 ​ $ 28,959 ​ ​ The following table represents a reconciliation of the fair values of our digital assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ 2024 2024 ​ Digital assets: ​ (in thousands) ​ Beginning balance ​ $ 28,335 ​ $ 15,811 ​ Additions ​ ​ 1,709 ​ ​ 7,848 ​ Dispositions ​ ​ (1,417) ​ ​ (3,137) ​ Fair value gains ​ ​ 332 ​ ​ 8,437 ​ Ending balance ​ $ 28,959 ​ $ 28,959 ​ ​ As discussed in Note 2 – New Accounting Standards, our beginning balance is inclusive of a cumulative-effect adjustment of $6.2 million as of January 1, 2024. Additions are the result of awarded digital assets received from our crypto-mining activities, while dispositions are the result of sales and payments for services. During the three and nine months ended September 30, 2024, we had digital asset dispositions of $1.4 million and $3.1 million, respectively, inclusive of realized gains of $1.0 million and $2.1 million, respectively.

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	9 Months Ended
	Sep. 30, 2024
FAIR VALUE MEASUREMENTS
FAIR VALUE MEASUREMENTS	7. FAIR VALUE MEASUREMENTS ​ The following table summarizes certain fair value measurements within the hierarchy not included elsewhere in these notes: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value ​ ​ Carrying Value Level 1 Level 2 Level 3 ​ ​ (in thousands) ​ September 30, 2024 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Recorded on a recurring basis: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Digital assets (1) ​ $ 28,959 ​ $ 28,959 ​ $ — ​ $ — ​ Additional disclosures: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Long-term debt ​ $ 496,958 ​ $ — ​ $ 528,540 ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2023 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Additional disclosures: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Long-term debt ​ $ 347,584 ​ $ — ​ $ 347,116 ​ $ — ​ (1) As discussed in Note 2 – New Accounting Standards, we adopted ASU 2023-08 effective January 1, 2024. Prior to our adoption, our digital assets were not recorded at fair value on a recurring basis. ​ The carrying amounts for cash equivalents, accounts receivable, accounts payable, accrued and other liabilities approximate fair value due to the short maturity of those instruments. ​ The fair value of our digital assets is based on an exchange quoted price. See Note 6 – Digital Assets for more information on our digital assets. ​ The estimated fair value of our long-term debt, including current maturities, is based on interest rates that we believe are currently available to us in active markets for issuance of debt with similar terms and remaining maturities. See Note 8 – Long-Term Debt for additional information on our long-term debt.

LONG-TERM DEBT

LONG-TERM DEBT	9 Months Ended
	Sep. 30, 2024
LONG-TERM DEBT
LONG-TERM DEBT	8. LONG-TERM DEBT ​ Long-term debt consists of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Unamortized Discount and ​ ​ ​ Principal ​ Debt Issuance Costs ​ ​ ​ September 30, ​ December 31, ​ September 30, ​ December 31, ​ ​ 2024 2023 2024 2023 ​ ​ (in thousands) ​ Revolving credit facility ​ $ — ​ $ — ​ $ (7,788) ​ $ (8,118) ​ Term loan ​ 49,219 ​ 60,938 ​ (1,375) ​ (1,416) ​ 8.625% Senior notes due 2029 ​ ​ 400,000 ​ ​ — ​ ​ (9,204) ​ ​ — ​ 7.5% Senior notes due 2025 ​ — ​ 284,607 ​ — ​ (891) ​ Securitization facility ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ June 2020 equipment financing ​ ​ — ​ ​ 2,039 ​ ​ — ​ ​ — ​ February 2024 equipment financing ​ ​ 47,739 ​ ​ — ​ ​ — ​ ​ — ​ ​ ​ 496,958 ​ 347,584 ​ (18,367) ​ (10,425) ​ Less current maturities ​ (26,669) ​ (20,789) ​ 4,394 ​ 451 ​ Total long-term debt ​ $ 470,289 ​ $ 326,795 ​ $ (13,973) ​ $ (9,974) ​ ​ Credit Facility ​ On January 13, 2023, Alliance Coal, as borrower, entered into a Credit Agreement with various financial institutions which was amended on June 12, 2024 (the "Credit Agreement"). The Credit Agreement provides for a $425 million revolving credit facility which includes a sublimit of $15.0 million for swingline borrowings and permits the issuance of letters of credit up to the full amount of the Credit Facility (the "Revolving Credit Facility"), and for a term loan in an aggregate principal amount of $75 million (the "Term Loan"). The Revolving Credit Facility also includes an incremental facility providing for an increase of $100.0 million at our option subject to lenders agreeing to participate in such incremental facility. The Credit Agreement matures on March 9, 2028, at which time the aggregate outstanding principal amount of all Revolving Credit Facility advances and all Term Loan advances are required to be repaid in full. Interest is payable quarterly, with principal on the Term Loan due in quarterly installments equal to 6.25% of the outstanding balance of the Term Loan on the Credit Agreement amendment date ​ The Revolving Credit Facility is underwritten by a syndicate of several financial institutions and the obligations of the lenders are individual obligations, which means the failure of one or more lenders to be able to fund its obligation does not relieve the remaining lenders from funding their obligations. Based on our diligence, including discussions with representatives of certain of these financial institutions, as of September 30, 2024 we have no reason to believe that the banks within our syndicate are facing financial difficulties, defaults or limited liquidity situations that would cause them to be unable to fund their obligations under the Credit Agreement. However, should any of the banks in our syndicate experience conditions in the future that limit their ability to fund their obligations, the amount available under the Revolving Credit Facility could be reduced. ​ The Credit Agreement is guaranteed by ARLP and certain of its subsidiaries, including the Intermediate Partnership and most of the direct and indirect subsidiaries of Alliance Coal (the "Subsidiary Guarantors"). The Credit Agreement also is secured by substantially all of the assets of the Subsidiary Guarantors and Alliance Coal. Borrowings under the Credit Agreement bear interest, at our option, at either (i) an adjusted one-month, three-month or six-month term rate based on the secured overnight financing rate published by the Federal Reserve Bank of New York, plus the applicable margin or (ii) the base rate plus the applicable margin. The base rate is the highest of (i) the Overnight Bank Funding Rate plus 0.50%, (ii) the Administrative Agent's prime rate, and (iii) the Daily Simple Secured Overnight Financing Rate plus 100 basis points. The applicable margin for borrowings under the Credit Agreement are determined by reference to the Consolidated Debt to Consolidated Cash Flow Ratio. For borrowings under the Term Loan, we elected the one-month term rate, with applicable margin, which was 8.2% as of September 30, 2024. At September 30, 2024, we had $41.0 million of letters of credit outstanding with $384.0 million available for borrowing under the Revolving Credit Facility. We incur an annual commitment fee of 0.50% on the undrawn portion of the Revolving Credit Facility. We utilize the Credit Agreement, as appropriate, for working capital requirements, capital expenditures and investments, scheduled debt payments and distribution payments. ​ The Credit Agreement contains various restrictions affecting Alliance Coal and its subsidiaries, including, among other things, restrictions on incurrence of additional indebtedness and liens, sale of assets, investments, mergers and consolidations and transactions with affiliates. In each case, these restrictions are subject to various exceptions. In addition, restrictions apply to cash distributions by Alliance Coal to the Intermediate Partnership if such distribution would result in exceeding the debt of Alliance Coal to cash flow ratio (as determined in the Credit Agreement) being more than 1.0 to 1.0 or in Alliance Coal having liquidity of less than $200 million. The Credit Agreement requires us to maintain (a) a debt of Alliance Coal to cash flow ratio of not more than 1.5 to 1.0 , (b) a consolidated debt of Alliance Coal and the Intermediate Partnership to cash flow ratio of not more than 2.5 to 1.0 and (c) an interest coverage ratio of not less than 3.0 to 1.0 , in each case, during the four most recently ended fiscal quarters. The debt of Alliance Coal to cash flow ratio, consolidated debt of Alliance Coal and the Intermediate Partnership to cash flow ratio, and interest coverage ratio were 0.17 to 1.0 , 0.84 to 1.0 and 43.19 to 1.0 , respectively, for the trailing twelve months ended September 30, 2024. We were in compliance with the covenants of the Credit Agreement as of September 30, 2024 and anticipate remaining in compliance with the covenants. ​ 8.625% Senior Notes due 2029 ​ On June 12, 2024, the Intermediate Partnership and Alliance Resource Finance Corporation (as co-issuer), a wholly owned subsidiary of the Intermediate Partnership ("Alliance Finance"), issued an aggregate principal amount of $400.0 million of senior unsecured notes due 2029 (the "2029 Senior Notes") in a private placement to qualified institutional buyers. The 2029 Senior Notes have a term of five years , maturing on June 15, 2029 and accrue interest at an annual rate of 8.625% . Interest is payable semi-annually in arrears on each June 15 and December 15. The 2029 Senior Notes are guaranteed, jointly and severally, on a senior unsecured basis by ARLP, certain of ARLP's wholly owned oil and gas and coal royalties subsidiaries and each of ARLP's subsidiaries that guarantee obligations under the Credit Agreement. The indenture governing the 2029 Senior Notes contains customary terms, events of default and covenants relating to, among other things, the incurrence of debt, the payment of distributions or similar restricted payments, undertaking transactions with affiliates and limitations on asset sales. ​ At any time prior to June 15, 2026, the issuers may redeem up to 35% of the aggregate principal amount of the 2029 Senior Notes at a redemption price equal to 108.625% of the principal amount redeemed, plus accrued and unpaid interest, if any, to, but excluding, the redemption date, with an amount of cash not greater than the net proceeds from one or more equity offerings. The issuers may also redeem all or a part of the 2029 Senior Notes at any time on or after June 15, 2026, at the redemption prices set forth in the indenture, plus accrued and unpaid interest, if any, to, but excluding, the redemption date. At any time prior to June 15, 2026, the issuers may redeem the 2029 Senior Notes at a redemption price equal to the principal amount plus a "make-whole" premium, plus accrued and unpaid interest, if any, to, but excluding, the redemption date. ​ In addition, if prior to June 15, 2026, a Specified Minerals Disposition (as defined in the indenture governing the 2029 Senior Notes and which involves oil and gas mineral interests) occurs, the issuers will be required to make an offer to purchase up to 40% of the aggregate principal amount of 2029 Senior Notes then outstanding at an offer price in cash in an amount equal to 108.625% of the principal amount thereof, plus accrued and unpaid interest, if any, to the date of purchase. ​ 7.5% Senior Notes due 2025 ​ On April 24, 2017, the Intermediate Partnership and Alliance Finance (as co-issuer) issued an aggregate principal amount of $400.0 million of senior unsecured notes due 2025 in a private placement to qualified institutional buyers. The 7.5% Senior Notes due 2025 had a term of eight years , maturing on May 1, 2025 and accrued interest at an annual rate of 7.5% . In June 2024, we used a portion of the net proceeds from the offering of the 2029 Senior Notes to redeem the outstanding balance of the 7.5% Senior Notes due 2025. ​ Accounts Receivable Securitization ​ Certain direct and indirect wholly owned subsidiaries of our Intermediate Partnership are party to a $90.0 million accounts receivable securitization facility ("Securitization Facility") which matures in January 2025. Under the Securitization Facility, certain subsidiaries sell certain trade receivables on an ongoing basis to our Intermediate Partnership, which then sells the trade receivables to AROP Funding, LLC ("AROP Funding"), a wholly owned bankruptcy-remote special purpose subsidiary of our Intermediate Partnership, which in turn borrows on a revolving basis up to $90.0 million secured by the trade receivables. After the sale, Alliance Coal, as servicer of the assets, collects the receivables on behalf of AROP Funding. The Securitization Facility bears interest based on a short-term bank yield index. On September 30, 2024, we had $11.7 million of letters of credit outstanding with $78.3 million available for borrowing under the Securitization Facility. The agreement governing the Securitization Facility contains customary terms and conditions, including limitations with regards to certain customer credit ratings. ​ June 2020 Equipment Financing ​ On June 5, 2020, the Intermediate Partnership entered into an equipment financing arrangement accounted for as debt, wherein the Intermediate Partnership received $14.7 million in exchange for conveying its interest in certain equipment owned indirectly by the Intermediate Partnership and entering into a master lease agreement for that equipment (the "June 2020 Equipment Financing"). The June 2020 Equipment Financing contained customary terms and events of default and provided for forty-eight monthly payments with an implicit interest rate of 6.1% . The June 2020 Equipment Financing matured on June 5, 2024 and the equipment reverted back to the Intermediate Partnership. ​ February 2024 Equipment Financing ​ On February 28, 2024, Alliance Coal entered into an equipment financing arrangement accounted for as debt, wherein Alliance Coal received $54.6 million in exchange for conveying its interest in certain equipment owned indirectly by Alliance Coal and entering into a master lease agreement for that equipment (the "February 2024 Equipment Financing"). The February 2024 Equipment Financing contains customary terms and events of default and provides for forty-eight monthly payments with an implicit interest rate of 8.29% , maturing on February 28, 2028. Upon maturity, the equipment will revert to Alliance Coal.

INCOME TAXES

INCOME TAXES	9 Months Ended
	Sep. 30, 2024
INCOME TAXES
INCOME TAXES	9. INCOME TAXES ​ Components of income tax expense are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ ​ 2024 2023 2024 2023 ​ ​ (in thousands) ​ Current: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Federal ​ $ 4,567 ​ $ 5,429 ​ $ 13,791 ​ $ 13,676 ​ State ​ 320 ​ 373 ​ 975 ​ 946 ​ ​ ​ 4,887 ​ 5,802 ​ 14,766 ​ 14,622 ​ Deferred: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Federal ​ (712) ​ (2,077) ​ (1,678) ​ (2,598) ​ State ​ (52) ​ (324) ​ (156) ​ (383) ​ ​ ​ (764) ​ (2,401) ​ (1,834) ​ (2,981) ​ Income tax expense ​ $ 4,123 ​ $ 3,401 ​ $ 12,932 ​ $ 11,641 ​ ​ The effective income tax rates for our income tax expense for the three and nine months ended September 30, 2024 and 2023 are less than the federal statutory rate, primarily due to the portion of income not subject to income taxes. ​ Our 2020 through 2023 tax years remain open to examination by tax authorities, and certain lower-tier partnership income tax returns for the tax years ended December 31, 2020 and 2021 are being audited by the Internal Revenue Service.

VARIABLE INTEREST ENTITIES

VARIABLE INTEREST ENTITIES	9 Months Ended
	Sep. 30, 2024
VARIABLE INTEREST ENTITIES
VARIABLE INTEREST ENTITIES	10. VARIABLE INTEREST ENTITIES ​ AllDale I & II and Cavalier Minerals ​ We own the general partner interests and, including the limited partner interests we hold through our ownership in Cavalier Minerals JV, LLC ("Cavalier Minerals"), approximately 97% of the limited partner interests in AllDale Minerals LP ("AllDale I") and AllDale Minerals II, LP ("AllDale II", and collectively with AllDale I, "AllDale I & II"). As the general partner of AllDale I & II, we are entitled to receive 20.0% of all distributions from AllDale I & II with the remaining 80.0% allocated to limited partners based upon ownership percentages. ​ Cavalier Minerals owns approximately 72% of the limited partner interests in AllDale I & II. We own the managing member interest and a 96% member interest in Cavalier Minerals. Bluegrass Minerals Management, LLC ("Bluegrass Minerals") owns a 4% member interest in Cavalier Minerals and a profits interest which entitles it to receive distributions equal to 25% of all distributions (including in liquidation) after all members have recovered their investment. All members have recovered their investment and Bluegrass Minerals began receiving its profits interest distributions in late 2022. ​ We have concluded that AllDale I, AllDale II and Cavalier Minerals are variable interest entities ("VIEs") which we consolidate as the primary beneficiary because we have the power to direct the activities that most significantly impact the economic performance of AllDale I, AllDale II and Cavalier Minerals in addition to having substantial equity ownership. ​ Our share of Cavalier Minerals' investment in AllDale I & II is eliminated in consolidation and Bluegrass Minerals' investment in Cavalier Minerals is accounted for as noncontrolling ownership interest on our condensed consolidated balance sheets. Additionally, earnings attributable to Bluegrass Minerals are recognized as noncontrolling interest in our condensed consolidated statements of income. ​ The following table presents the carrying amounts and classification of AllDale I & II's assets and liabilities included in our condensed consolidated balance sheets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ ​ ​ 2024 2023 ​ Assets (liabilities): (in thousands) Cash and cash equivalents ​ $ 6,040 ​ $ 4,690 ​ Trade receivables ​ 12,581 ​ 16,058 ​ Total property, plant and equipment, net ​ 377,236 ​ 389,767 ​ Accounts payable ​ ​ (253) ​ ​ (175) ​ Accrued taxes other than income taxes ​ (682) ​ ​ (958) ​ ​ AllDale III ​ AllDale Minerals III, LP ("AllDale III") owns oil & gas mineral interests in areas around the oil & gas mineral interests we own. Alliance Minerals owns a 13.9% limited partner interest in AllDale III. Alliance Minerals' investment in AllDale III is subject to a 25% profits interest for the general partner that is subject to a return hurdle equal to the greater of 125% of cumulative capital contributions and a 10% internal rate of return, and following an 80/20 "catch-up" provision for the general partner. ​ We have concluded that AllDale III is a VIE that we do not consolidate. AllDale III is structured as a limited partnership with the limited partners (1) not having the ability to remove the general partner and (2) not participating significantly in the operational decisions. We are not the primary beneficiary of AllDale III because we do not have the power to direct the activities that most significantly impact AllDale III's economic performance. See Note 11 – Equity Investments for more information about the accounting for our investment in AllDale III. ​ Francis ​ On April 5, 2022, we invested $20 million in Francis Renewable Energy, LLC ("Francis"), in the form of a convertible note. Our convertible note matured on April 1, 2023 and was converted into a preferred equity interest in Francis. Prior to conversion, we had determined the note more closely represented equity as opposed to debt. Therefore, we accounted for the convertible note as an equity contribution even though we did not participate in Francis' earnings or losses and were not eligible to receive distributions during the term of the note. Subsequent to the conversion on April 1, 2023, we participate in earnings and losses and are eligible to receive distributions. As of September 30, 2024, we held approximately 16.7% of Francis' equity. ​ We have concluded that Francis is a VIE that we do not consolidate. Francis' management structure is similar to a limited partnership with the non-managing members (i) not having the ability to remove the managing member and (ii) not participating significantly in the operational decisions. We are not the primary beneficiary of Francis because we do not have the power to direct the activities that most significantly impact Francis's economic performance. See Note 11 – Equity Investments for more information about the accounting for our investment in Francis. ​ NGP ET IV ​ On June 2, 2022, we committed to purchase $25.0 million of limited partner interests in NGP Energy Transition, L.P. ("NGP ET IV"), a private equity fund sponsored by NGP and focused on investments that are part of the global transition toward a lower carbon economy. This commitment represents a 3.6% interest in NGP ET IV. As of September 30, 2024, we have funded $8.0 million of this commitment. ​

EQUITY INVESTMENTS

EQUITY INVESTMENTS	9 Months Ended
	Sep. 30, 2024
EQUITY INVESTMENTS
EQUITY INVESTMENTS	11. EQUITY INVESTMENT S ​ AllDale III ​ We account for our ownership interest in the income or loss of AllDale III as an equity method investment. We record equity income or loss based on AllDale III's distribution structure. The changes in our equity method investment in AllDale III were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ 2024 2023 2024 2023 ​ ​ ​ (in thousands) ​ Beginning balance ​ $ 23,218 ​ $ 24,451 ​ $ 23,933 ​ $ 25,284 ​ Equity method investment income ​ ​ 496 ​ ​ 578 ​ ​ 1,781 ​ ​ 1,719 ​ Distributions received ​ ​ (849) ​ ​ (904) ​ ​ (2,849) ​ ​ (2,878) ​ Ending balance ​ $ 22,865 ​ $ 24,125 ​ $ 22,865 ​ $ 24,125 ​ ​ Francis ​ We account for our ownership interest in the income or loss of Francis as an equity method investment. Prior to the conversion of our convertible note, we did not participate in Francis' earnings or losses; however, upon conversion on April 1, 2023 we began participating. As a development stage company, Francis depends primarily on capital contributions to meet its operating and debt obligations. The changes in our equity method investment in Francis were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ 2024 2023 2024 2023 ​ ​ (in thousands) ​ Beginning balance ​ $ 14,518 ​ $ 17,380 ​ $ 16,487 ​ $ 20,000 ​ Equity method investment loss ​ ​ (2,487) ​ ​ (2,435) ​ ​ (4,456) ​ ​ (5,055) ​ Change in our share of Francis' net assets ​ ​ (5,118) ​ ​ — ​ ​ (5,118) ​ ​ — ​ Ending balance ​ $ 6,913 ​ $ 14,945 ​ $ 6,913 ​ $ 14,945 ​ ​ We have not impaired our initial investment and currently believe that the carrying value of our investment is recoverable. ​ NGP ET IV ​ We account for our ownership interest in the income or loss of NGP ET IV as an equity method investment. The changes in our equity method investment in NGP ET IV were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ 2024 2023 2024 2023 ​ ​ ​ (in thousands) ​ Beginning balance ​ $ 7,352 ​ $ 4,958 ​ $ 6,083 ​ $ 4,087 ​ Contributions ​ ​ 108 ​ ​ 923 ​ ​ 1,398 ​ ​ 2,257 ​ Equity method investment income (loss) ​ ​ (336) ​ ​ 15 ​ ​ (357) ​ ​ (448) ​ Ending balance ​ $ 7,124 ​ $ 5,896 ​ $ 7,124 ​ $ 5,896 ​ ​ Infinitum ​ During 2022, we purchased $42.0 million of Series D Preferred Stock ("Series D Preferred Stock") in Infinitum Electric, Inc. ("Infinitum"), a Texas-based startup developer and manufacturer of electric motors featuring printed circuit board stators. On September 8, 2023, ​ Ascend ​ On August 22, 2023, we purchased $25.0 million of Series D Preferred Stock (the "Ascend Preferred Stock") in Ascend Elements, Inc. ("Ascend"), a U.S.-based manufacturer and recycler of sustainable, engineered battery materials for electric vehicles. The Ascend Preferred Stock provides for non-cumulative dividends when and if declared by Ascend's board of directors. Each share is convertible, at any time, at our option, into shares of common stock of Ascend. We account for our ownership interest in Ascend as an equity investment without a readily determinable fair value. Absent an observable price change, it is not practicable to estimate the fair value of our investment in Ascend because of the lack of a quoted market price for our ownership interests. Therefore, we use a measurement alternative other than fair value to account for our investment.

PARTNERS' CAPITAL

PARTNERS' CAPITAL	9 Months Ended
	Sep. 30, 2024
PARTNERS' CAPITAL.
PARTNERS' CAPITAL	12. PARTNERS' CAPITAL ​ Distributions ​ Distributions paid or declared during 2023 and 2024 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Payment Date Per Unit Cash Distribution Total Cash Distribution ​ ​ ​ ​ ​ (in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ February 14, 2023 ​ $ 0.70 ​ $ 91,938 ​ May 15, 2023 ​ ​ 0.70 ​ ​ 90,930 ​ August 14, 2023 ​ ​ 0.70 ​ ​ 90,899 ​ November 14, 2023 ​ ​ 0.70 ​ ​ 90,812 ​ Total ​ $ 2.80 ​ $ 364,579 ​ ​ ​ ​ ​ ​ ​ ​ ​ February 14, 2024 ​ $ 0.70 ​ $ 91,246 ​ May 15, 2024 ​ ​ 0.70 ​ ​ 90,736 ​ August 14, 2024 ​ ​ 0.70 ​ ​ 90,725 ​ November 14, 2024 (1) ​ ​ 0.70 ​ ​ ​ ​ Total ​ $ 2.80 ​ $ 272,707 ​ (1) On October 28, 2024, we declared this quarterly distribution payable on November 14, 2024 to all unitholders of record as of November 7, 2024. ​ Unit Repurchase Program ​ In January 2023, the board of directors of MGP authorized a $93.5 million increase to the unit repurchase program authorizing us to be able to repurchase up to a total of $100.0 million of ARLP common units from that date. No units were repurchased during the nine months ended September 30, 2024. During the nine months ended September 30, 2023, we repurchased and retired 929,842 units at an average unit price of $20.90 for an aggregate purchase price of $19.4 million. Since inception of the unit repurchase program, we have repurchased and retired 6,390,446 units at an average unit price of $17.67 for an aggregate purchase price of $112.9 million. ​ Change in Partners' Capital ​ The following tables present the quarterly change in Partners' Capital for the three and nine months ended September 30, 2024 and 2023: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accumulated ​ ​ ​ ​ ​ ​ ​ ​ ​ Number of ​ Limited ​ Other ​ ​ ​ ​ ​ ​ ​ ​ ​ Limited Partner ​ Partners' ​ Comprehensive ​ Noncontrolling ​ Total Partners' ​ ​ Units Capital Income (Loss) Interest Capital ​ ​ (in thousands, except unit data) ​ Balance at January 1, 2024 127,125,437 ​ $ 1,896,027 ​ $ (61,525) ​ $ 24,095 ​ $ 1,858,597 ​ Cumulative-effect adjustment (see Note 2) ​ — ​ ​ 6,232 ​ ​ — ​ ​ — ​ ​ 6,232 ​ Comprehensive income: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income — ​ 158,057 ​ — ​ ​ 1,510 159,567 ​ Actuarially determined long-term liability adjustments — ​ — ​ 923 ​ — 923 ​ Total comprehensive income ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 160,490 ​ Settlement of deferred compensation plans ​ 936,544 ​ ​ (13,292) ​ ​ — ​ ​ — ​ ​ (13,292) ​ Common unit-based compensation — ​ 2,604 ​ ​ — ​ ​ — ​ ​ 2,604 ​ Distributions on deferred common unit-based compensation — ​ (2,261) ​ ​ — ​ ​ — ​ ​ (2,261) ​ Distributions from consolidated company to noncontrolling interest ​ — ​ ​ — ​ ​ — ​ ​ (1,981) ​ ​ (1,981) ​ Distributions to Partners — ​ ​ (88,985) ​ ​ — ​ ​ — ​ ​ (88,985) ​ Balance at March 31, 2024 ​ 128,061,981 ​ ​ 1,958,382 ​ ​ (60,602) ​ ​ 23,624 ​ ​ 1,921,404 ​ Comprehensive income: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income — ​ 100,187 ​ — ​ ​ 1,322 101,509 ​ Actuarially determined long-term liability adjustments — ​ — ​ 957 ​ — 957 ​ Total comprehensive income ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 102,466 ​ Common unit-based compensation — ​ 2,926 ​ ​ — ​ ​ — ​ ​ 2,926 ​ Distributions on deferred common unit-based compensation — ​ (1,091) ​ ​ — ​ ​ — ​ ​ (1,091) ​ Distributions from consolidated company to noncontrolling interest ​ — ​ ​ — ​ ​ — ​ ​ (1,942) ​ ​ (1,942) ​ Distributions to Partners — ​ ​ (89,645) ​ ​ — ​ ​ — ​ ​ (89,645) ​ Balance at June 30, 2024 ​ 128,061,981 ​ ​ 1,970,759 ​ ​ (59,645) ​ ​ 23,004 ​ ​ 1,934,118 ​ Comprehensive income: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income — ​ 86,281 ​ — ​ ​ 635 86,916 ​ Actuarially determined long-term liability adjustments — ​ — ​ 1,022 ​ — 1,022 ​ Total comprehensive income ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 87,938 ​ Settlement of deferred compensation plans ​ — ​ ​ (2,252) ​ ​ — ​ ​ — ​ ​ (2,252) ​ Common unit-based compensation — ​ 3,032 ​ ​ — ​ ​ — ​ ​ 3,032 ​ Distributions on deferred common unit-based compensation — ​ (1,082) ​ ​ — ​ ​ — ​ ​ (1,082) ​ Distributions from consolidated company to noncontrolling interest ​ — ​ ​ — ​ ​ — ​ ​ (1,883) ​ ​ (1,883) ​ Distributions to Partners — ​ ​ (89,643) ​ ​ — ​ ​ — ​ ​ (89,643) ​ Other ​ — ​ ​ (5,118) ​ ​ — ​ ​ — ​ ​ (5,118) ​ Balance at September 30, 2024 128,061,981 ​ $ 1,961,977 ​ $ (58,623) ​ $ 21,756 ​ $ 1,925,110 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accumulated ​ ​ ​ ​ ​ ​ ​ ​ ​ Number of ​ Limited ​ General ​ Other ​ ​ ​ ​ ​ ​ ​ ​ ​ Limited Partner ​ Partners' ​ Partner's ​ Comprehensive ​ Noncontrolling ​ Total Partners' ​ ​ Units Capital Capital Income (Loss) Interest Capital ​ ​ (in thousands, except unit data) ​ Balance at January 1, 2023 127,195,219 ​ $ 1,656,025 ​ $ 66,548 ​ $ (41,054) ​ $ 26,507 ​ $ 1,708,026 ​ Comprehensive income: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income — ​ 189,801 ​ 1,384 ​ — ​ ​ 1,493 192,678 ​ Actuarially determined long-term liability adjustments — ​ — ​ — ​ 565 ​ — 565 ​ Total comprehensive income ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 193,243 ​ Settlement of deferred compensation plans ​ 860,060 ​ ​ (9,320) ​ ​ — ​ ​ — ​ ​ — ​ ​ (9,320) ​ Purchase of units under unit repurchase program ​ (860,060) ​ ​ (18,209) ​ ​ — ​ ​ — ​ ​ — ​ ​ (18,209) ​ Common unit-based compensation — ​ 2,830 ​ ​ — ​ ​ — ​ ​ — ​ ​ 2,830 ​ Distributions on deferred common unit-based compensation — ​ (2,901) ​ ​ — ​ ​ — ​ ​ — ​ ​ (2,901) ​ Distributions from consolidated company to affiliate noncontrolling interest ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ (2,288) ​ ​ (2,288) ​ JC Resources acquisition ​ ​ ​ ​ (7,251) ​ ​ (64,999) ​ ​ ​ ​ ​ ​ ​ ​ (72,250) ​ Cash retained by JC Resources in acquisition ​ — ​ ​ — ​ ​ (2,933) ​ ​ — ​ ​ — ​ ​ (2,933) ​ Distributions to Partners — ​ ​ (89,037) ​ ​ — ​ ​ — ​ ​ — ​ ​ (89,037) ​ Balance at March 31, 2023 127,195,219 ​ ​ 1,721,938 ​ ​ — ​ ​ (40,489) ​ ​ 25,712 ​ ​ 1,707,161 ​ Comprehensive income: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income — ​ 169,790 ​ — ​ — ​ ​ 1,515 171,305 ​ Actuarially determined long-term liability adjustments — ​ — ​ — ​ 563 ​ — 563 ​ Total comprehensive income ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 171,868 ​ Settlement of deferred compensation plans ​ — ​ ​ (1,014) ​ ​ — ​ ​ — ​ ​ — ​ ​ (1,014) ​ Purchase of units under unit repurchase program ​ (69,782) ​ ​ (1,223) ​ ​ — ​ ​ — ​ ​ — ​ ​ (1,223) ​ Common unit-based compensation — ​ 3,121 ​ ​ — ​ ​ — ​ ​ — ​ ​ 3,121 ​ Distributions on deferred common unit-based compensation — ​ (1,895) ​ ​ — ​ ​ — ​ ​ — ​ ​ (1,895) ​ Distributions from consolidated company to noncontrolling interest ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ (2,226) ​ ​ (2,226) ​ Distributions to Partners — ​ ​ (89,035) ​ ​ — ​ ​ — ​ ​ — ​ ​ (89,035) ​ Balance at June 30, 2023 127,125,437 ​ ​ 1,801,682 ​ ​ — ​ ​ (39,926) ​ ​ 25,001 ​ ​ 1,786,757 ​ Comprehensive income: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income — ​ 153,699 ​ — ​ — ​ ​ 1,652 155,351 ​ Actuarially determined long-term liability adjustments — ​ — ​ — ​ 561 ​ — 561 ​ Total comprehensive income ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 155,912 ​ Common unit-based compensation — ​ 3,239 ​ ​ — ​ ​ — ​ ​ — ​ ​ 3,239 ​ Distributions on deferred common unit-based compensation — ​ (1,911) ​ ​ — ​ ​ — ​ ​ — ​ ​ (1,911) ​ Distributions from consolidated company to noncontrolling interest ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ (2,081) ​ ​ (2,081) ​ Distributions to Partners — ​ ​ (88,988) ​ ​ — ​ ​ — ​ ​ — ​ ​ (88,988) ​ Balance at September 30, 2023 127,125,437 ​ $ 1,867,721 ​ $ — ​ $ (39,365) ​ $ 24,572 ​ $ 1,852,928 ​ ​

REVENUE FROM CONTRACTS WITH CUS

REVENUE FROM CONTRACTS WITH CUSTOMERS	9 Months Ended
	Sep. 30, 2024
REVENUE FROM CONTRACTS WITH CUSTOMERS
REVENUE FROM CONTRACTS WITH CUSTOMERS	13. REVENUE FROM CONTRACTS WITH CUSTOMERS ​ The following table illustrates the disaggregation of our revenues by type, including a reconciliation to our segment presentation as presented in Note 18 – Segment Information. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Coal Operations ​ Royalties ​ Other, ​ ​ ​ ​ ​ ​ Illinois ​ ​ ​ ​ Corporate and ​ ​ ​ ​ Basin Appalachia Oil & Gas Coal Elimination Consolidated ​ ​ ​ (in thousands) ​ Three Months Ended September 30, 2024 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Coal sales ​ $ 337,816 ​ $ 194,831 ​ $ — ​ $ — ​ $ — ​ $ 532,647 ​ Oil & gas royalties ​ ​ — ​ ​ — ​ ​ 34,448 ​ ​ — ​ ​ — ​ ​ 34,448 ​ Coal royalties ​ ​ — ​ ​ — ​ ​ — ​ ​ 16,647 ​ ​ (16,647) ​ ​ — ​ Transportation revenues ​ ​ 16,764 ​ ​ 7,853 ​ ​ — ​ ​ — ​ ​ — ​ ​ 24,617 ​ Other revenues ​ ​ 2,331 ​ ​ 480 ​ ​ 240 ​ ​ — ​ ​ 18,806 ​ ​ 21,857 ​ Total revenues ​ $ 356,911 ​ $ 203,164 ​ $ 34,688 ​ $ 16,647 ​ $ 2,159 ​ $ 613,569 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, 2023 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Coal sales ​ $ 342,744 ​ $ 206,379 ​ $ — ​ $ — ​ $ — ​ $ 549,123 ​ Oil & gas royalties ​ ​ — ​ ​ — ​ ​ 34,125 ​ ​ — ​ ​ — ​ ​ 34,125 ​ Coal royalties ​ ​ — ​ ​ — ​ ​ — ​ ​ 16,763 ​ ​ (16,763) ​ ​ — ​ Transportation revenues ​ ​ 25,992 ​ ​ 8,972 ​ ​ — ​ ​ — ​ ​ — ​ ​ 34,964 ​ Other revenues ​ ​ 2,897 ​ ​ 449 ​ ​ 2,186 ​ ​ — ​ ​ 12,777 ​ ​ 18,309 ​ Total revenues ​ $ 371,633 ​ $ 215,800 ​ $ 36,311 ​ $ 16,763 ​ $ (3,986) ​ $ 636,521 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2024 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Coal sales ​ $ 1,040,419 ​ $ 566,766 ​ $ — ​ $ — ​ $ — ​ $ 1,607,185 ​ Oil & gas royalties ​ ​ — ​ ​ — ​ ​ 107,907 ​ ​ — ​ ​ — ​ ​ 107,907 ​ Coal royalties ​ ​ — ​ ​ — ​ ​ — ​ ​ 51,933 ​ ​ (51,933) ​ ​ — ​ Transportation revenues ​ ​ 61,810 ​ ​ 20,261 ​ ​ — ​ ​ — ​ ​ — ​ ​ 82,071 ​ Other revenues ​ ​ 7,284 ​ ​ 2,363 ​ ​ 563 ​ ​ 10 ​ ​ 51,233 ​ ​ 61,453 ​ Total revenues ​ $ 1,109,513 ​ $ 589,390 ​ $ 108,470 ​ $ 51,943 ​ $ (700) ​ $ 1,858,616 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2023 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Coal sales ​ $ 1,011,467 ​ $ 676,771 ​ $ — ​ $ — ​ $ — ​ $ 1,688,238 ​ Oil & gas royalties ​ ​ — ​ ​ — ​ ​ 101,709 ​ ​ — ​ ​ — ​ ​ 101,709 ​ Coal royalties ​ ​ — ​ ​ — ​ ​ — ​ ​ 48,843 ​ ​ (48,843) ​ ​ — ​ Transportation revenues ​ ​ 68,498 ​ ​ 27,231 ​ ​ — ​ ​ — ​ ​ — ​ ​ 95,729 ​ Other revenues ​ ​ 7,466 ​ ​ 1,299 ​ ​ 3,551 ​ ​ — ​ ​ 43,287 ​ ​ 55,603 ​ Total revenues ​ $ 1,087,431 ​ $ 705,301 ​ $ 105,260 ​ $ 48,843 ​ $ (5,556) ​ $ 1,941,279 ​ ​ The following table illustrates the amount of our transaction price for all current coal supply contracts allocated to performance obligations that are unsatisfied or partially unsatisfied as of September 30, 2024 and disaggregated by segment and contract duration. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2027 and ​ ​ ​ 2024 2025 2026 Thereafter Total ​ ​ (in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Illinois Basin Coal Operations coal revenues ​ $ 361,441 ​ $ 668,579 ​ $ 415,415 ​ $ 355,100 ​ $ 1,800,535 Appalachia Coal Operations coal revenues ​ ​ 202,928 ​ ​ 431,993 ​ ​ 100,010 ​ ​ 30,105 ​ ​ 765,036 Total coal revenues (1) ​ $ 564,369 ​ $ 1,100,572 ​ $ 515,425 ​ $ 385,205 ​ $ 2,565,571 (1) Coal revenues generally consists of consolidated revenues excluding our Oil & Gas Royalties segment as well as intercompany revenues from our Coal Royalties segment .

EARNINGS PER LIMITED PARTNER UN

EARNINGS PER LIMITED PARTNER UNIT	9 Months Ended
	Sep. 30, 2024
EARNINGS PER LIMITED PARTNER UNIT
EARNINGS PER LIMITED PARTNER UNIT	14 . EARNINGS PER LIMITED PARTNER UNIT ​ We utilize the two-class method in calculating basic and diluted earnings per limited partner unit ("EPU"). Subsequent to the acquisition of oil & gas net royalty acres from JC Resources LP on February 22, 2023 (the "JC Resources Acquisition"), net income attributable to ARLP is allocated to limited partners and participating securities with nonforfeitable distributions or distribution equivalents, while net losses attributable to ARLP are allocated only to limited partners but not to participating securities. Prior to the JC Resources Acquisition, in addition to limited partners and participating securities allocations, amounts were also allocated to our general partner for historical earnings from the mineral interests acquired in the JC Resources Acquisition. ​ Our participating securities are outstanding restricted unit awards under our Long-Term Incentive Plan ("LTIP") and phantom units in notional accounts under our Supplemental Executive Retirement Plan ("SERP") and the MGP Amended and Restated Deferred Compensation Plan for Directors ("Directors' Deferred Compensation Plan"). ​ The following is a reconciliation of net income attributable to ARLP used for calculating basic and diluted earnings per unit and the weighted-average units used in computing EPU: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ 2024 2023 2024 2023 ​ ​ (in thousands, except per unit data) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income attributable to ARLP ​ $ 86,281 ​ $ 153,699 ​ $ 344,525 ​ $ 514,674 ​ Less: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ General partner's interest in net income attributable to ARLP ​ — ​ — ​ — ​ (1,384) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Limited partners' interest in net income attributable to ARLP ​ 86,281 ​ 153,699 ​ 344,525 ​ 513,290 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Less: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Distributions to participating securities ​ (1,616) ​ (2,414) ​ (4,984) ​ (7,242) ​ Undistributed earnings attributable to participating securities ​ — ​ (1,652) ​ (1,378) ​ (6,596) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income attributable to ARLP available to limited partners ​ $ 84,665 ​ $ 149,633 ​ $ 338,163 ​ $ 499,452 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted-average limited partner units outstanding – basic and diluted ​ 128,062 ​ 127,125 ​ 127,932 ​ 127,199 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Earnings per limited partner unit - basic and diluted (1) ​ $ 0.66 ​ $ 1.18 ​ $ 2.64 ​ $ 3.93 ​ (1) Diluted EPU gives effect to all potentially dilutive common units outstanding during the period using the treasury stock method. Diluted EPU excludes all potentially dilutive units calculated under the treasury stock method if their effect is anti-dilutive. The combined total of LTIP, SERP and Directors' Deferred Compensation Plan units of 1,863 and 1,915 for the three and nine months ended September 30, 2024, respectively, and 2,759 and 2,878 for the three and nine months ended September 30, 2023, respectively, were considered anti-dilutive under the treasury stock method .

WORKERS' COMPENSATION AND PNEUM

WORKERS' COMPENSATION AND PNEUMOCONIOSIS	9 Months Ended
	Sep. 30, 2024
WORKERS' COMPENSATION AND PNEUMOCONIOSIS
WORKERS' COMPENSATION AND PNEUMOCONIOSIS	15. WORKERS' COMPENSATION AND PNEUMOCONIOSIS ​ The changes in the workers' compensation liability, including current and long-term liability balances, for each of the periods presented were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, ​ September 30, ​ ​ ​ 2024 2023 2024 2023 ​ ​ ​ (in thousands) ​ Beginning balance ​ $ 47,194 ​ $ 51,108 ​ $ 47,975 ​ $ 49,452 ​ Changes in accruals ​ 3,658 ​ 3,001 ​ 10,148 ​ 9,071 ​ Payments ​ (3,784) ​ (3,503) ​ (11,278) ​ (10,008) ​ Interest accretion ​ 509 ​ 551 ​ 1,527 ​ 1,652 ​ Valuation loss (gain) (1) ​ — ​ — ​ (795) ​ 990 ​ Ending balance ​ $ 47,577 ​ $ 51,157 ​ $ 47,577 ​ $ 51,157 ​ (1) Our estimate of the liability for the present value of current workers′ compensation benefits is based on our actuarial calculations. Our actuarial calculations are based on a blend of actuarial projection methods and numerous assumptions including claims development patterns, mortality, medical costs and interest rates. The valuation gain in 2024 is due to an increase in the discount rate from 4.66% on December 31, 2023 to 5.18% on June 30, 2024. The valuation loss in 2023 is due to adverse claims development. ​ We limit our exposure to traumatic injury claims by purchasing a high deductible insurance policy that starts paying benefits after deductibles for a claim have been met. The deductible level may vary by claim year. Our workers' compensation liability above is presented on a gross basis and does not include our expected receivables from our insurance policy. Our receivables for traumatic injury claims under this policy as of September 30, 2024 are $4.1 million and are included in Other long-term assets ​ Certain of our mine operating entities are liable under state statutes and the Federal Coal Mine Health and Safety Act of 1969, as amended, to pay pneumoconiosis, or black lung, benefits to eligible employees and former employees and their dependents. Components of the net periodic benefit cost for each of the periods presented are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ ​ 2024 2023 2024 2023 ​ ​ (in thousands) ​ Service cost ​ $ 864 ​ $ 678 ​ $ 2,583 ​ $ 2,022 Interest cost (1) ​ 1,558 ​ 1,237 ​ 4,674 ​ 3,713 ​ Net amortization (1) ​ 839 ​ 345 ​ 2,517 ​ 1,036 ​ Net periodic benefit cost ​ $ 3,261 ​ $ 2,260 ​ $ 9,774 ​ $ 6,771 ​ (1) Interest cost and net amortization are included in the Other income (expense) line item within our condensed consolidated statements of income.

COMMON UNIT-BASED COMPENSATION

COMMON UNIT-BASED COMPENSATION PLANS	9 Months Ended
	Sep. 30, 2024
COMMON UNIT-BASED COMPENSATION PLANS
COMMON UNIT-BASED COMPENSATION PLANS	16. COMMON UNIT-BASED COMPENSATION PLANS ​ Long-Term Incentive Plan ​ A summary of non-vested LTIP grants of restricted units is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number of units Weighted average grant date fair value per unit Intrinsic value ​ ​ ​ ​ ​ ​ ​ (in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Non-vested grants at January 1, 2024 ​ 2,710,344 ​ $ 10.91 ​ ​ 51,405 ​ Granted (1) 455,574 ​ ​ 19.69 ​ ​ ​ ​ Vested (2) (1,582,422) ​ 6.53 ​ ​ ​ ​ Forfeited (38,204) ​ 16.08 ​ ​ ​ ​ Non-vested grants at September 30, 2024 1,545,292 ​ 17.87 ​ ​ 38,632 ​ (1) The restricted units granted during 2024 have certain minimum-value guarantees per unit, regardless of whether the awards vest. (2) During the nine months ended September 30, 2024, we issued 936,544 unrestricted common units to the LTIP participants. The remaining vested units were settled in cash to satisfy tax withholding. ​ LTIP expense for grants of restricted units was $2.4 million and $ 2.7 million for the three months ended September 30, 2024 and 2023, respectively, and $6.8 million and $7.7 million for the nine months ended September 30, 2024 and 2023, respectively. The total obligation associated with LTIP grants of restricted units as of September 30, 2024 was $ 15.9 million and is included in the partners' capital Limited partners-common unitholders line item on our condensed consolidated balance sheets. As of September 30, 2024, there was $11.7 million in total unrecognized compensation expense related to the non-vested LTIP restricted unit grants that are expected to vest. That expense is expected to be recognized over a weighted-average period of 1.1 years. ​ Supplemental Executive Retirement Plan and Directors' Deferred Compensation Plan ​ A summary of SERP and Directors' Deferred Compensation Plan activity is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number of units Weighted average fair value per unit Intrinsic value ​ ​ ​ ​ ​ ​ ​ (in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Phantom units outstanding as of January 1, 2024 ​ 811,946 ​ $ 20.44 ​ $ 17,197 ​ Granted ​ 79,695 ​ ​ 21.85 ​ ​ ​ ​ Settled (1) (96,873) ​ ​ 23.89 ​ ​ ​ ​ Phantom units outstanding as of September 30, 2024 794,768 ​ 20.78 ​ ​ 19,869 ​ (1) During the nine months ended September 30, 2024, we purchased 54,152 ARLP common units on the open market to settle the account of a participant under the SERP. Units purchased and delivered to the participant were net of units settled in cash to satisfy tax withholding obligations. ​ Total SERP and Directors' Deferred Compensation Plan expense was $0.7 million and $0.6 million for the three months ended September 30, 2024 and 2023, respectively, and $2.0 million and $1.8 million for the nine months ended September 30, 2024 and 2023, respectively. As of September 30, 2024, the total obligation associated with the SERP and Directors' Deferred Compensation Plan was $16.5 million and is included in the partners' capital Limited partners-common unitholders

COMPONENTS OF PENSION PLAN NET

COMPONENTS OF PENSION PLAN NET PERIODIC BENEFIT COSTS	9 Months Ended
	Sep. 30, 2024
COMPONENTS OF PENSION PLAN NET PERIODIC BENEFIT COSTS
COMPONENTS OF PENSION PLAN NET PERIODIC BENEFIT COSTS	17. COMPONENTS OF PENSION PLAN NET PERIODIC BENEFIT COSTS ​ Eligible employees at certain of our mining operations participate in a defined benefit plan (the "Pension Plan") that we sponsor. The Pension Plan is currently closed to new applicants and participants in the Pension Plan are no longer receiving benefit accruals for service. The benefit formula for the Pension Plan is a fixed dollar unit based on years of service. Components of the net periodic benefit credit for each of the periods presented are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ ​ 2024 2023 2024 2023 ​ ​ (in thousands) ​ Interest cost ​ $ 1,289 ​ $ 1,294 ​ $ 3,817 ​ $ 3,885 ​ Expected return on plan assets ​ (1,752) ​ (1,553) ​ (5,278) ​ (4,668) ​ Amortization of prior service cost ​ ​ 47 ​ ​ 47 ​ ​ 140 ​ ​ 140 ​ Amortization of net loss ​ 136 ​ 169 ​ 245 ​ 513 ​ Net periodic benefit credit (1) ​ $ (280) ​ $ (43) ​ $ (1,076) ​ $ (130) ​ (1) Net periodic benefit credit for the Pension Plan is included in the Other income (expense) line item within our condensed consolidated statements of income. ​ We do not expect to make material contributions to the Pension Plan during 2024.

SEGMENT INFORMATION

SEGMENT INFORMATION	9 Months Ended
	Sep. 30, 2024
SEGMENT INFORMATION
SEGMENT INFORMATION	18. SEGMENT INFORMATION ​ We operate in the United States as a diversified natural resource company that generates operating and royalty income from the production and marketing of coal to major domestic and international utilities, and industrial users as well as royalty income from oil & gas mineral interests. We aggregate multiple operating segments into four reportable segments, Illinois Basin Coal Operations, Appalachia Coal Operations, Oil & Gas Royalties and Coal Royalties. We also have an "all other" category referred to as Other, Corporate and Elimination. Our two coal operations reportable segments correspond to major coal producing regions in the eastern United States with similar economic characteristics including coal quality, geology, coal marketing opportunities, mining and transportation methods and regulatory issues. The two coal operations reportable segments include seven mining complexes operating in Illinois, Indiana, Kentucky, Maryland, Pennsylvania, and West Virginia and a coal loading terminal in Indiana on the Ohio River. Our Oil & Gas Royalties reportable segment includes our oil & gas mineral interests which are located primarily in the Permian (Delaware and Midland), Anadarko (SCOOP/STACK) and Williston (Bakken) basins. The operations within our Oil & Gas Royalties reportable segment primarily include receiving royalties and lease bonuses for our oil & gas mineral interests. Our Coal Royalties reportable segment includes coal mineral reserves and resources owned or leased by Alliance Resource Properties, which are either (a) leased to our mining complexes or (b) near our coal mining operations but not yet leased. ​ The Illinois Basin Coal Operations reportable segment includes (a) the Gibson County Coal, LLC's mining complex, (b) the Warrior Coal, LLC mining complex, (c) the River View Coal, LLC mining complex and (d) the Hamilton County Coal, LLC mining complex. The segment also includes our Mt. Vernon Transfer Terminal, LLC ("Mt. Vernon") coal loading terminal in Indiana which operates on the Ohio River, Mid-America Carbonates, LLC and other support services, and our non-operating mining complexes. ​ The Appalachia Coal Operations reportable segment includes (a) the Mettiki mining complex, (b) the Tunnel Ridge, LLC mining complex and (c) the MC Mining complex. ​ The Oil & Gas Royalties reportable segment includes oil & gas mineral interests held by Alliance Minerals through its consolidated subsidiaries as well as equity interests held in AllDale III (Note 11 – Equity Investments). ​ The Coal Royalties reportable segment includes coal mineral reserves and resources owned or leased by Alliance Resource Properties that are (a) leased to certain of our mining complexes in both the Illinois Basin Coal Operations and Appalachia Coal Operations reportable segments or (b) located near our operations and external mining operations. Approximately 63% of the coal sold by our mines is leased from our Coal Royalties entities. ​ Other, Corporate and Elimination includes marketing and administrative activities, the Matrix Group, our investments in Francis, Infinitum, NGP ET IV, and Ascend (see Note 11 – Equity Investments), Wildcat Insurance, LLC which assists the ARLP Partnership with its insurance requirements, AROP Funding and Alliance Finance (both discussed in Note 8 – Long-Term Debt) and our crypto-mining activities. The eliminations included in Other, Corporate and Elimination primarily represent the intercompany coal royalty transactions described above between our Coal Royalties reportable segment and our coal operations' mines. ​ Reportable segment results are presented below. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Coal Operations ​ Royalties ​ Other, ​ ​ ​ ​ ​ Illinois ​ ​ ​ ​ ​ Corporate and ​ ​ ​ ​ Basin Appalachia Oil & Gas Coal ​ Elimination Consolidated ​ ​ (in thousands) Three Months Ended September 30, 2024 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Revenues - Outside (1) ​ $ 356,911 ​ $ 203,164 ​ $ 34,688 ​ $ — ​ $ 18,806 ​ $ 613,569 ​ Revenues - Intercompany ​ ​ — ​ ​ — ​ ​ — ​ ​ 16,647 ​ ​ (16,647) ​ ​ — ​ Total revenues (1) ​ ​ 356,911 ​ ​ 203,164 ​ ​ 34,688 ​ ​ 16,647 ​ ​ 2,159 ​ ​ 613,569 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Segment Adjusted EBITDA Expense (2) ​ 225,498 ​ 157,792 ​ 5,844 ​ 5,589 ​ (1,006) ​ 393,717 ​ Segment Adjusted EBITDA (3) ​ 114,649 ​ 37,518 ​ 28,706 ​ 11,058 ​ 342 ​ 192,273 ​ Capital expenditures (4) ​ 68,512 ​ 32,471 ​ — ​ — ​ 9,315 ​ 110,298 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, 2023 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Revenues - Outside (1) ​ $ 371,633 ​ $ 215,800 ​ $ 36,311 ​ $ — ​ $ 12,777 ​ $ 636,521 ​ Revenues - Intercompany ​ ​ — ​ ​ — ​ ​ — ​ ​ 16,763 ​ ​ (16,763) ​ ​ — ​ Total revenues (1) ​ ​ 371,633 ​ ​ 215,800 ​ ​ 36,311 ​ ​ 16,763 ​ ​ (3,986) ​ ​ 636,521 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Segment Adjusted EBITDA Expense (2) ​ 213,209 ​ 131,997 ​ 3,873 ​ 6,851 ​ (5,524) ​ 350,406 ​ Segment Adjusted EBITDA (3) ​ 132,428 ​ ​ 74,832 ​ ​ 31,366 ​ ​ 9,912 ​ ​ (881) ​ 247,657 ​ Capital expenditures (4) ​ 59,833 ​ 30,304 ​ — ​ — ​ 20,202 ​ 110,339 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2024 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Revenues - Outside (1) ​ $ 1,109,513 ​ $ 589,390 ​ $ 108,470 ​ $ 10 ​ $ 51,233 ​ $ 1,858,616 ​ Revenues - Intercompany ​ ​ — ​ ​ — ​ ​ — ​ ​ 51,933 ​ ​ (51,933) ​ ​ — ​ Total revenues (1) ​ ​ 1,109,513 ​ ​ 589,390 ​ ​ 108,470 ​ ​ 51,943 ​ ​ (700) ​ ​ 1,858,616 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Segment Adjusted EBITDA Expense (2) ​ 674,753 ​ ​ 412,056 ​ ​ 15,419 ​ ​ 18,485 ​ ​ (5,498) ​ 1,115,215 ​ Segment Adjusted EBITDA (3) ​ 372,950 ​ ​ 157,072 ​ ​ 91,366 ​ ​ 33,457 ​ ​ (14) ​ 654,831 ​ Total assets ​ 1,029,389 ​ ​ 534,449 ​ ​ 806,332 ​ ​ 313,044 ​ ​ 348,959 ​ 3,032,173 ​ Capital expenditures (4) ​ 230,618 ​ ​ 91,715 ​ ​ — ​ ​ — ​ ​ 13,253 ​ 335,586 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2023 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Revenues - Outside (1) ​ $ 1,087,431 ​ $ 705,301 ​ $ 105,260 ​ $ — ​ $ 43,287 ​ $ 1,941,279 ​ Revenues - Intercompany ​ ​ — ​ ​ — ​ ​ — ​ ​ 48,843 ​ ​ (48,843) ​ ​ — ​ Total revenues (1) ​ ​ 1,087,431 ​ ​ 705,301 ​ ​ 105,260 ​ ​ 48,843 ​ ​ (5,556) ​ ​ 1,941,279 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Segment Adjusted EBITDA Expense (2) ​ 634,944 ​ ​ 377,115 ​ ​ 11,859 ​ ​ 17,836 ​ ​ (13,618) ​ 1,028,136 ​ Segment Adjusted EBITDA (3) ​ 383,987 ​ ​ 300,955 ​ ​ 90,461 ​ ​ 31,007 ​ ​ 2,560 ​ 808,970 ​ Total assets ​ 882,943 ​ ​ 459,742 ​ ​ 767,415 ​ ​ 319,930 ​ ​ 384,011 ​ 2,814,041 ​ Capital expenditures (4) ​ 179,284 ​ ​ 94,119 ​ ​ — ​ ​ 400 ​ ​ 21,553 ​ 295,356 ​ (1) Revenues included in the Other, Corporate and Elimination column are attributable to intercompany eliminations, which are primarily intercompany coal royalty eliminations, outside revenues at the Matrix Group and awarded digital assets received for our crypto-mining activities. ​ (2) Segment Adjusted EBITDA Expense (a non-GAAP financial measure) includes operating expenses, coal purchases, if applicable, and other income or expense as adjusted to remove certain items from operating expenses that we characterize as unrepresentative of our ongoing operations. Transportation expenses are excluded as these expenses are passed through to our customers and, consequently, we do not realize any gain or loss on transportation revenues. Segment Adjusted EBITDA Expense is used as a supplemental financial measure by our management to assess the operating performance of our segments. Segment Adjusted EBITDA Expense is a key component of Segment Adjusted EBITDA in addition to coal sales, royalty revenues and other revenues. The exclusion of corporate general and administrative expenses from Segment Adjusted EBITDA Expense allows management to focus solely on the evaluation of segment operating performance as it primarily relates to our operating expenses. ​ The following is a reconciliation of Operating expenses (excluding depreciation, depletion and amortization), ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ ​ 2024 2023 2024 2023 ​ ​ (in thousands) ​ Operating expenses (excluding depreciation, depletion and amortization) ​ $ 384,844 ​ $ 339,099 ​ $ 1,100,308 ​ $ 1,012,224 ​ Litigation expense accrual ​ ​ — ​ ​ — ​ ​ (15,250) ​ — ​ Outside coal purchases ​ 8,192 ​ 11,530 ​ 27,912 ​ 15,739 ​ Other expense (income) ​ ​ 681 ​ ​ (223) ​ ​ 2,245 ​ ​ 173 ​ Segment Adjusted EBITDA Expense ​ $ 393,717 ​ $ 350,406 ​ $ 1,115,215 ​ $ 1,028,136 ​ ​ (3) Segment Adjusted EBITDA (a non-GAAP financial measure) is defined as net income attributable to ARLP before net interest expense, income taxes, depreciation, depletion and amortization and general and administrative expenses adjusted for certain items that we characterize as unrepresentative of our ongoing operations. Segment Adjusted EBITDA is a key component of consolidated EBITDA, which is used as a supplemental financial measure by management and by external users of our financial statements such as investors, commercial banks, research analysts and others. We believe that the presentation of EBITDA provides useful information to investors regarding our performance and results of operations because EBITDA, when used in conjunction with related GAAP financial measures, (i) provides additional information about our core operating performance and ability to generate and distribute cash flow, (ii) provides investors with the financial analytical framework upon which we base financial, operational, compensation and planning decisions and (iii) presents a measurement that investors, rating agencies and debt holders have indicated is useful in assessing us and our results of operations. ​ Segment Adjusted EBITDA is also used as a supplemental financial measure by our management for reasons similar to those stated in the previous explanation of EBITDA. In addition, the exclusion of corporate general and administrative expenses from consolidated Segment Adjusted EBITDA allows management to focus solely on the evaluation of segment operating profitability as it relates to our revenues and operating expenses, which are primarily controlled by our segments. ​ The following is a reconciliation of Net income ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ ​ 2024 2023 2024 2023 ​ ​ (in thousands) ​ Net income ​ $ 86,916 ​ $ 155,351 ​ $ 347,992 ​ $ 519,334 ​ Noncontrolling interest ​ ​ (635) ​ ​ (1,652) ​ ​ (3,467) ​ ​ (4,660) ​ Net income attributable to ARLP ​ $ 86,281 ​ $ 153,699 ​ $ 344,525 ​ $ 514,674 ​ General and administrative ​ 21,878 ​ 20,097 ​ 64,569 ​ 61,312 ​ Depreciation, depletion and amortization ​ 72,971 ​ 65,393 ​ 204,974 ​ 199,582 ​ Interest expense, net ​ 7,352 ​ 5,067 ​ 21,018 ​ 21,761 ​ Change in fair value of digital assets ​ ​ (332) ​ ​ — ​ ​ (8,437) ​ ​ — ​ Litigation expense accrual ​ ​ — ​ ​ — ​ ​ 15,250 ​ ​ — ​ Income tax expense ​ 4,123 ​ 3,401 ​ 12,932 ​ 11,641 ​ Consolidated Segment Adjusted EBITDA ​ $ 192,273 ​ $ 247,657 ​ $ 654,831 ​ $ 808,970 ​ ​ (4) Capital expenditures exclude $72.3 million paid for the JC Resources Acquisition for the nine months ended September 30, 2023, $10.5 million and $10.0 million paid towards oil & gas reserve acquisitions for the three months ended September 30, 2024 and 2023, respectively, and $15.2 million and $13.9 million paid towards oil & gas reserve acquisitions for the nine months ended September 30, 2024 and 2023, respectively (See Note 3 – Acquisitions) .

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ 86,281	$ 153,699	$ 344,525	$ 514,674

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Sep. 30, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

ORGANIZATION AND PRESENTATION (

ORGANIZATION AND PRESENTATION (Policies)	9 Months Ended
	Sep. 30, 2024
ORGANIZATION AND PRESENTATION
Consolidation	Significant Relationships Referenced in Notes to Condensed Consolidated Financial Statements ​ ● References to "we," "us," "our" or "ARLP Partnership" mean the business and operations of Alliance Resource Partners, L.P., the parent company, as well as its consolidated subsidiaries. ● References to "ARLP" mean Alliance Resource Partners, L.P., individually as the parent company, and not on a consolidated basis. ● References to "MGP" mean Alliance Resource Management GP, LLC, ARLP's general partner. ● References to "Intermediate Partnership" mean Alliance Resource Operating Partners, L.P., the intermediate partnership of Alliance Resource Partners, L.P. ● References to "Alliance Coal" mean Alliance Coal, LLC, an indirect wholly owned subsidiary of ARLP. ● References to "Alliance Minerals" mean Alliance Minerals, LLC, an indirect wholly owned subsidiary of ARLP. ● References to "Alliance Resource Properties" mean Alliance Resource Properties, LLC, an indirect wholly owned subsidiary of ARLP. ​ Organization ​ ARLP is a Delaware limited partnership listed on the NASDAQ Global Select Market under the ticker symbol "ARLP." ARLP was formed in May 1999 and completed its initial public offering on August 19, 1999 when it acquired substantially all of the coal production and marketing assets of Alliance Resource Holdings, Inc., a Delaware corporation, and its subsidiaries. We are managed by our general partner, MGP, a Delaware limited liability company which holds a non-economic general partner interest in ARLP.
Basis of Presentation	Basis of Presentation ​ The accompanying condensed consolidated financial statements include the accounts and operations of the ARLP Partnership and present our financial position as of September 30, 2024 and December 31, 2023, the results of our operations and comprehensive income for the three and nine months ended September 30, 2024 and 2023 and cash flows for the nine months ended September 30, 2024 and 2023. All intercompany transactions and accounts have been eliminated. Certain immaterial amounts in the prior period have been reclassified to conform to the current period presentation. ​ These condensed consolidated financial statements and notes are prepared pursuant to the rules and regulations of the Securities and Exchange Commission for interim reporting and do not include all the information normally included with financial statements prepared in accordance with generally accepted accounting principles ("GAAP") of the United States. These financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2023. ​ These condensed consolidated financial statements and notes are unaudited. However, in the opinion of management, these condensed consolidated financial statements reflect all normal recurring adjustments necessary for a fair presentation of the results for the periods presented. Results for interim periods are not necessarily indicative of results to be expected for the full year ending December 31, 2024.
Use of Estimates	Use of Estimates ​ The preparation of the ARLP Partnership's condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts and disclosures in our condensed consolidated financial statements. Actual results could differ from those estimates.
Digital Assets	Digital Assets ​ We began our crypto-mining activities during the second half of 2020 as we started mining bitcoin as a pilot project to monetize already paid for, yet underutilized, electricity load. We continue to periodically be awarded digital assets through our crypto-mining activities. The awards are accounted for as revenue and valued at the exchange quoted price at the time they are awarded. Beginning January 1, 2024, with our adoption of the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2023-08, Intangibles - Goodwill and Other - Crypto Assets (Subtopic 350-60) Digital assets Change in fair value of digital assets
New Accounting Standards	New Accounting Standards Issued and Adopted ​ In December 2023, the FASB issued ASU 2023-08, Intangibles - Goodwill and Other - Crypto Assets (Subtopic 350-60) ​ New Accounting Standards Issued and Not Yet Adopted ​ In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures ​ In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures

INVENTORIES (Tables)

INVENTORIES (Tables)	9 Months Ended
	Sep. 30, 2024
INVENTORIES
Schedule of inventories	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ ​ ​ 2024 2023 ​ ​ (in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ Coal ​ $ 95,333 ​ $ 56,549 ​ Finished goods (net of reserve for obsolescence of $723 and $728, respectively) ​ ​ 3,812 ​ ​ 3,908 ​ Work in process ​ ​ 580 ​ ​ 791 ​ Raw materials ​ ​ 1,838 ​ ​ 2,144 ​ ​ ​ ​ 101,563 ​ ​ 63,392 ​ Supplies (net of reserve for obsolescence of $8,036 and $7,439, respectively) ​ 75,940 ​ 64,164 ​ Total inventories, net ​ $ 177,503 ​ $ 127,556 ​

DIGITAL ASSETS (Tables)

DIGITAL ASSETS (Tables)	9 Months Ended
	Sep. 30, 2024
DIGITAL ASSETS
Schedule of digital assets	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2024 ​ ​ ​ Units ​ Cost Basis ​ Fair Value ​ Digital assets: ​ (in thousands, except unit data) ​ Bitcoin ​ ​ 457.24 ​ $ 16,327 ​ $ 28,959 ​ Total ​ ​ ​ ​ $ 16,327 ​ $ 28,959 ​
Schedule of digital assets fair value reconciliation	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ 2024 2024 ​ Digital assets: ​ (in thousands) ​ Beginning balance ​ $ 28,335 ​ $ 15,811 ​ Additions ​ ​ 1,709 ​ ​ 7,848 ​ Dispositions ​ ​ (1,417) ​ ​ (3,137) ​ Fair value gains ​ ​ 332 ​ ​ 8,437 ​ Ending balance ​ $ 28,959 ​ $ 28,959 ​

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	9 Months Ended
	Sep. 30, 2024
FAIR VALUE MEASUREMENTS
Summary of fair value measurements within the hierarchy	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value ​ ​ Carrying Value Level 1 Level 2 Level 3 ​ ​ (in thousands) ​ September 30, 2024 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Recorded on a recurring basis: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Digital assets (1) ​ $ 28,959 ​ $ 28,959 ​ $ — ​ $ — ​ Additional disclosures: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Long-term debt ​ $ 496,958 ​ $ — ​ $ 528,540 ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2023 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Additional disclosures: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Long-term debt ​ $ 347,584 ​ $ — ​ $ 347,116 ​ $ — ​ (1) As discussed in Note 2 – New Accounting Standards, we adopted ASU 2023-08 effective January 1, 2024. Prior to our adoption, our digital assets were not recorded at fair value on a recurring basis.

LONG-TERM DEBT (Tables)

LONG-TERM DEBT (Tables)	9 Months Ended
	Sep. 30, 2024
LONG-TERM DEBT
Schedule of long-term debt	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Unamortized Discount and ​ ​ ​ Principal ​ Debt Issuance Costs ​ ​ ​ September 30, ​ December 31, ​ September 30, ​ December 31, ​ ​ 2024 2023 2024 2023 ​ ​ (in thousands) ​ Revolving credit facility ​ $ — ​ $ — ​ $ (7,788) ​ $ (8,118) ​ Term loan ​ 49,219 ​ 60,938 ​ (1,375) ​ (1,416) ​ 8.625% Senior notes due 2029 ​ ​ 400,000 ​ ​ — ​ ​ (9,204) ​ ​ — ​ 7.5% Senior notes due 2025 ​ — ​ 284,607 ​ — ​ (891) ​ Securitization facility ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ June 2020 equipment financing ​ ​ — ​ ​ 2,039 ​ ​ — ​ ​ — ​ February 2024 equipment financing ​ ​ 47,739 ​ ​ — ​ ​ — ​ ​ — ​ ​ ​ 496,958 ​ 347,584 ​ (18,367) ​ (10,425) ​ Less current maturities ​ (26,669) ​ (20,789) ​ 4,394 ​ 451 ​ Total long-term debt ​ $ 470,289 ​ $ 326,795 ​ $ (13,973) ​ $ (9,974) ​

INCOME TAXES (Tables)

INCOME TAXES (Tables)	9 Months Ended
	Sep. 30, 2024
INCOME TAXES
Components of income tax expense	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ ​ 2024 2023 2024 2023 ​ ​ (in thousands) ​ Current: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Federal ​ $ 4,567 ​ $ 5,429 ​ $ 13,791 ​ $ 13,676 ​ State ​ 320 ​ 373 ​ 975 ​ 946 ​ ​ ​ 4,887 ​ 5,802 ​ 14,766 ​ 14,622 ​ Deferred: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Federal ​ (712) ​ (2,077) ​ (1,678) ​ (2,598) ​ State ​ (52) ​ (324) ​ (156) ​ (383) ​ ​ ​ (764) ​ (2,401) ​ (1,834) ​ (2,981) ​ Income tax expense ​ $ 4,123 ​ $ 3,401 ​ $ 12,932 ​ $ 11,641 ​

VARIABLE INTEREST ENTITIES (Tab

VARIABLE INTEREST ENTITIES (Tables)	9 Months Ended
	Sep. 30, 2024
VARIABLE INTEREST ENTITIES
Schedule of assets and liabilities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ ​ ​ 2024 2023 ​ Assets (liabilities): (in thousands) Cash and cash equivalents ​ $ 6,040 ​ $ 4,690 ​ Trade receivables ​ 12,581 ​ 16,058 ​ Total property, plant and equipment, net ​ 377,236 ​ 389,767 ​ Accounts payable ​ ​ (253) ​ ​ (175) ​ Accrued taxes other than income taxes ​ (682) ​ ​ (958) ​

EQUITY INVESTMENTS (Tables)

EQUITY INVESTMENTS (Tables)	9 Months Ended
	Sep. 30, 2024
AllDale III
Investments
Schedule of changes in equity method investments	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ 2024 2023 2024 2023 ​ ​ ​ (in thousands) ​ Beginning balance ​ $ 23,218 ​ $ 24,451 ​ $ 23,933 ​ $ 25,284 ​ Equity method investment income ​ ​ 496 ​ ​ 578 ​ ​ 1,781 ​ ​ 1,719 ​ Distributions received ​ ​ (849) ​ ​ (904) ​ ​ (2,849) ​ ​ (2,878) ​ Ending balance ​ $ 22,865 ​ $ 24,125 ​ $ 22,865 ​ $ 24,125 ​
Francis Renewable Energy
Investments
Schedule of changes in equity method investments	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ 2024 2023 2024 2023 ​ ​ (in thousands) ​ Beginning balance ​ $ 14,518 ​ $ 17,380 ​ $ 16,487 ​ $ 20,000 ​ Equity method investment loss ​ ​ (2,487) ​ ​ (2,435) ​ ​ (4,456) ​ ​ (5,055) ​ Change in our share of Francis' net assets ​ ​ (5,118) ​ ​ — ​ ​ (5,118) ​ ​ — ​ Ending balance ​ $ 6,913 ​ $ 14,945 ​ $ 6,913 ​ $ 14,945 ​
NGP ET IV
Investments
Schedule of changes in equity method investments	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ 2024 2023 2024 2023 ​ ​ ​ (in thousands) ​ Beginning balance ​ $ 7,352 ​ $ 4,958 ​ $ 6,083 ​ $ 4,087 ​ Contributions ​ ​ 108 ​ ​ 923 ​ ​ 1,398 ​ ​ 2,257 ​ Equity method investment income (loss) ​ ​ (336) ​ ​ 15 ​ ​ (357) ​ ​ (448) ​ Ending balance ​ $ 7,124 ​ $ 5,896 ​ $ 7,124 ​ $ 5,896 ​

PARTNERS' CAPITAL (Tables)

PARTNERS' CAPITAL (Tables)	9 Months Ended
	Sep. 30, 2024
PARTNERS' CAPITAL.
Summary of quarterly per unit distribution paid	​ ​ ​ ​ ​ ​ ​ ​ Payment Date Per Unit Cash Distribution Total Cash Distribution ​ ​ ​ ​ ​ (in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ February 14, 2023 ​ $ 0.70 ​ $ 91,938 ​ May 15, 2023 ​ ​ 0.70 ​ ​ 90,930 ​ August 14, 2023 ​ ​ 0.70 ​ ​ 90,899 ​ November 14, 2023 ​ ​ 0.70 ​ ​ 90,812 ​ Total ​ $ 2.80 ​ $ 364,579 ​ ​ ​ ​ ​ ​ ​ ​ ​ February 14, 2024 ​ $ 0.70 ​ $ 91,246 ​ May 15, 2024 ​ ​ 0.70 ​ ​ 90,736 ​ August 14, 2024 ​ ​ 0.70 ​ ​ 90,725 ​ November 14, 2024 (1) ​ ​ 0.70 ​ ​ ​ ​ Total ​ $ 2.80 ​ $ 272,707 ​ (1) On October 28, 2024, we declared this quarterly distribution payable on November 14, 2024 to all unitholders of record as of November 7, 2024.
Summary of changes to Partners' Capital	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accumulated ​ ​ ​ ​ ​ ​ ​ ​ ​ Number of ​ Limited ​ Other ​ ​ ​ ​ ​ ​ ​ ​ ​ Limited Partner ​ Partners' ​ Comprehensive ​ Noncontrolling ​ Total Partners' ​ ​ Units Capital Income (Loss) Interest Capital ​ ​ (in thousands, except unit data) ​ Balance at January 1, 2024 127,125,437 ​ $ 1,896,027 ​ $ (61,525) ​ $ 24,095 ​ $ 1,858,597 ​ Cumulative-effect adjustment (see Note 2) ​ — ​ ​ 6,232 ​ ​ — ​ ​ — ​ ​ 6,232 ​ Comprehensive income: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income — ​ 158,057 ​ — ​ ​ 1,510 159,567 ​ Actuarially determined long-term liability adjustments — ​ — ​ 923 ​ — 923 ​ Total comprehensive income ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 160,490 ​ Settlement of deferred compensation plans ​ 936,544 ​ ​ (13,292) ​ ​ — ​ ​ — ​ ​ (13,292) ​ Common unit-based compensation — ​ 2,604 ​ ​ — ​ ​ — ​ ​ 2,604 ​ Distributions on deferred common unit-based compensation — ​ (2,261) ​ ​ — ​ ​ — ​ ​ (2,261) ​ Distributions from consolidated company to noncontrolling interest ​ — ​ ​ — ​ ​ — ​ ​ (1,981) ​ ​ (1,981) ​ Distributions to Partners — ​ ​ (88,985) ​ ​ — ​ ​ — ​ ​ (88,985) ​ Balance at March 31, 2024 ​ 128,061,981 ​ ​ 1,958,382 ​ ​ (60,602) ​ ​ 23,624 ​ ​ 1,921,404 ​ Comprehensive income: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income — ​ 100,187 ​ — ​ ​ 1,322 101,509 ​ Actuarially determined long-term liability adjustments — ​ — ​ 957 ​ — 957 ​ Total comprehensive income ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 102,466 ​ Common unit-based compensation — ​ 2,926 ​ ​ — ​ ​ — ​ ​ 2,926 ​ Distributions on deferred common unit-based compensation — ​ (1,091) ​ ​ — ​ ​ — ​ ​ (1,091) ​ Distributions from consolidated company to noncontrolling interest ​ — ​ ​ — ​ ​ — ​ ​ (1,942) ​ ​ (1,942) ​ Distributions to Partners — ​ ​ (89,645) ​ ​ — ​ ​ — ​ ​ (89,645) ​ Balance at June 30, 2024 ​ 128,061,981 ​ ​ 1,970,759 ​ ​ (59,645) ​ ​ 23,004 ​ ​ 1,934,118 ​ Comprehensive income: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income — ​ 86,281 ​ — ​ ​ 635 86,916 ​ Actuarially determined long-term liability adjustments — ​ — ​ 1,022 ​ — 1,022 ​ Total comprehensive income ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 87,938 ​ Settlement of deferred compensation plans ​ — ​ ​ (2,252) ​ ​ — ​ ​ — ​ ​ (2,252) ​ Common unit-based compensation — ​ 3,032 ​ ​ — ​ ​ — ​ ​ 3,032 ​ Distributions on deferred common unit-based compensation — ​ (1,082) ​ ​ — ​ ​ — ​ ​ (1,082) ​ Distributions from consolidated company to noncontrolling interest ​ — ​ ​ — ​ ​ — ​ ​ (1,883) ​ ​ (1,883) ​ Distributions to Partners — ​ ​ (89,643) ​ ​ — ​ ​ — ​ ​ (89,643) ​ Other ​ — ​ ​ (5,118) ​ ​ — ​ ​ — ​ ​ (5,118) ​ Balance at September 30, 2024 128,061,981 ​ $ 1,961,977 ​ $ (58,623) ​ $ 21,756 ​ $ 1,925,110 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accumulated ​ ​ ​ ​ ​ ​ ​ ​ ​ Number of ​ Limited ​ General ​ Other ​ ​ ​ ​ ​ ​ ​ ​ ​ Limited Partner ​ Partners' ​ Partner's ​ Comprehensive ​ Noncontrolling ​ Total Partners' ​ ​ Units Capital Capital Income (Loss) Interest Capital ​ ​ (in thousands, except unit data) ​ Balance at January 1, 2023 127,195,219 ​ $ 1,656,025 ​ $ 66,548 ​ $ (41,054) ​ $ 26,507 ​ $ 1,708,026 ​ Comprehensive income: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income — ​ 189,801 ​ 1,384 ​ — ​ ​ 1,493 192,678 ​ Actuarially determined long-term liability adjustments — ​ — ​ — ​ 565 ​ — 565 ​ Total comprehensive income ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 193,243 ​ Settlement of deferred compensation plans ​ 860,060 ​ ​ (9,320) ​ ​ — ​ ​ — ​ ​ — ​ ​ (9,320) ​ Purchase of units under unit repurchase program ​ (860,060) ​ ​ (18,209) ​ ​ — ​ ​ — ​ ​ — ​ ​ (18,209) ​ Common unit-based compensation — ​ 2,830 ​ ​ — ​ ​ — ​ ​ — ​ ​ 2,830 ​ Distributions on deferred common unit-based compensation — ​ (2,901) ​ ​ — ​ ​ — ​ ​ — ​ ​ (2,901) ​ Distributions from consolidated company to affiliate noncontrolling interest ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ (2,288) ​ ​ (2,288) ​ JC Resources acquisition ​ ​ ​ ​ (7,251) ​ ​ (64,999) ​ ​ ​ ​ ​ ​ ​ ​ (72,250) ​ Cash retained by JC Resources in acquisition ​ — ​ ​ — ​ ​ (2,933) ​ ​ — ​ ​ — ​ ​ (2,933) ​ Distributions to Partners — ​ ​ (89,037) ​ ​ — ​ ​ — ​ ​ — ​ ​ (89,037) ​ Balance at March 31, 2023 127,195,219 ​ ​ 1,721,938 ​ ​ — ​ ​ (40,489) ​ ​ 25,712 ​ ​ 1,707,161 ​ Comprehensive income: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income — ​ 169,790 ​ — ​ — ​ ​ 1,515 171,305 ​ Actuarially determined long-term liability adjustments — ​ — ​ — ​ 563 ​ — 563 ​ Total comprehensive income ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 171,868 ​ Settlement of deferred compensation plans ​ — ​ ​ (1,014) ​ ​ — ​ ​ — ​ ​ — ​ ​ (1,014) ​ Purchase of units under unit repurchase program ​ (69,782) ​ ​ (1,223) ​ ​ — ​ ​ — ​ ​ — ​ ​ (1,223) ​ Common unit-based compensation — ​ 3,121 ​ ​ — ​ ​ — ​ ​ — ​ ​ 3,121 ​ Distributions on deferred common unit-based compensation — ​ (1,895) ​ ​ — ​ ​ — ​ ​ — ​ ​ (1,895) ​ Distributions from consolidated company to noncontrolling interest ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ (2,226) ​ ​ (2,226) ​ Distributions to Partners — ​ ​ (89,035) ​ ​ — ​ ​ — ​ ​ — ​ ​ (89,035) ​ Balance at June 30, 2023 127,125,437 ​ ​ 1,801,682 ​ ​ — ​ ​ (39,926) ​ ​ 25,001 ​ ​ 1,786,757 ​ Comprehensive income: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income — ​ 153,699 ​ — ​ — ​ ​ 1,652 155,351 ​ Actuarially determined long-term liability adjustments — ​ — ​ — ​ 561 ​ — 561 ​ Total comprehensive income ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 155,912 ​ Common unit-based compensation — ​ 3,239 ​ ​ — ​ ​ — ​ ​ — ​ ​ 3,239 ​ Distributions on deferred common unit-based compensation — ​ (1,911) ​ ​ — ​ ​ — ​ ​ — ​ ​ (1,911) ​ Distributions from consolidated company to noncontrolling interest ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ (2,081) ​ ​ (2,081) ​ Distributions to Partners — ​ ​ (88,988) ​ ​ — ​ ​ — ​ ​ — ​ ​ (88,988) ​ Balance at September 30, 2023 127,125,437 ​ $ 1,867,721 ​ $ — ​ $ (39,365) ​ $ 24,572 ​ $ 1,852,928 ​ ​

REVENUE FROM CONTRACTS WITH C_2

REVENUE FROM CONTRACTS WITH CUSTOMERS (Tables)	9 Months Ended
	Sep. 30, 2024
REVENUE FROM CONTRACTS WITH CUSTOMERS
Schedule of disaggregation of revenues by type	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Coal Operations ​ Royalties ​ Other, ​ ​ ​ ​ ​ ​ Illinois ​ ​ ​ ​ Corporate and ​ ​ ​ ​ Basin Appalachia Oil & Gas Coal Elimination Consolidated ​ ​ ​ (in thousands) ​ Three Months Ended September 30, 2024 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Coal sales ​ $ 337,816 ​ $ 194,831 ​ $ — ​ $ — ​ $ — ​ $ 532,647 ​ Oil & gas royalties ​ ​ — ​ ​ — ​ ​ 34,448 ​ ​ — ​ ​ — ​ ​ 34,448 ​ Coal royalties ​ ​ — ​ ​ — ​ ​ — ​ ​ 16,647 ​ ​ (16,647) ​ ​ — ​ Transportation revenues ​ ​ 16,764 ​ ​ 7,853 ​ ​ — ​ ​ — ​ ​ — ​ ​ 24,617 ​ Other revenues ​ ​ 2,331 ​ ​ 480 ​ ​ 240 ​ ​ — ​ ​ 18,806 ​ ​ 21,857 ​ Total revenues ​ $ 356,911 ​ $ 203,164 ​ $ 34,688 ​ $ 16,647 ​ $ 2,159 ​ $ 613,569 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, 2023 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Coal sales ​ $ 342,744 ​ $ 206,379 ​ $ — ​ $ — ​ $ — ​ $ 549,123 ​ Oil & gas royalties ​ ​ — ​ ​ — ​ ​ 34,125 ​ ​ — ​ ​ — ​ ​ 34,125 ​ Coal royalties ​ ​ — ​ ​ — ​ ​ — ​ ​ 16,763 ​ ​ (16,763) ​ ​ — ​ Transportation revenues ​ ​ 25,992 ​ ​ 8,972 ​ ​ — ​ ​ — ​ ​ — ​ ​ 34,964 ​ Other revenues ​ ​ 2,897 ​ ​ 449 ​ ​ 2,186 ​ ​ — ​ ​ 12,777 ​ ​ 18,309 ​ Total revenues ​ $ 371,633 ​ $ 215,800 ​ $ 36,311 ​ $ 16,763 ​ $ (3,986) ​ $ 636,521 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2024 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Coal sales ​ $ 1,040,419 ​ $ 566,766 ​ $ — ​ $ — ​ $ — ​ $ 1,607,185 ​ Oil & gas royalties ​ ​ — ​ ​ — ​ ​ 107,907 ​ ​ — ​ ​ — ​ ​ 107,907 ​ Coal royalties ​ ​ — ​ ​ — ​ ​ — ​ ​ 51,933 ​ ​ (51,933) ​ ​ — ​ Transportation revenues ​ ​ 61,810 ​ ​ 20,261 ​ ​ — ​ ​ — ​ ​ — ​ ​ 82,071 ​ Other revenues ​ ​ 7,284 ​ ​ 2,363 ​ ​ 563 ​ ​ 10 ​ ​ 51,233 ​ ​ 61,453 ​ Total revenues ​ $ 1,109,513 ​ $ 589,390 ​ $ 108,470 ​ $ 51,943 ​ $ (700) ​ $ 1,858,616 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2023 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Coal sales ​ $ 1,011,467 ​ $ 676,771 ​ $ — ​ $ — ​ $ — ​ $ 1,688,238 ​ Oil & gas royalties ​ ​ — ​ ​ — ​ ​ 101,709 ​ ​ — ​ ​ — ​ ​ 101,709 ​ Coal royalties ​ ​ — ​ ​ — ​ ​ — ​ ​ 48,843 ​ ​ (48,843) ​ ​ — ​ Transportation revenues ​ ​ 68,498 ​ ​ 27,231 ​ ​ — ​ ​ — ​ ​ — ​ ​ 95,729 ​ Other revenues ​ ​ 7,466 ​ ​ 1,299 ​ ​ 3,551 ​ ​ — ​ ​ 43,287 ​ ​ 55,603 ​ Total revenues ​ $ 1,087,431 ​ $ 705,301 ​ $ 105,260 ​ $ 48,843 ​ $ (5,556) ​ $ 1,941,279 ​
Schedule of current coal supply contracts	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2027 and ​ ​ ​ 2024 2025 2026 Thereafter Total ​ ​ (in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Illinois Basin Coal Operations coal revenues ​ $ 361,441 ​ $ 668,579 ​ $ 415,415 ​ $ 355,100 ​ $ 1,800,535 Appalachia Coal Operations coal revenues ​ ​ 202,928 ​ ​ 431,993 ​ ​ 100,010 ​ ​ 30,105 ​ ​ 765,036 Total coal revenues (1) ​ $ 564,369 ​ $ 1,100,572 ​ $ 515,425 ​ $ 385,205 ​ $ 2,565,571 (1) Coal revenues generally consists of consolidated revenues excluding our Oil & Gas Royalties segment as well as intercompany revenues from our Coal Royalties segment .

EARNINGS PER LIMITED PARTNER _2

EARNINGS PER LIMITED PARTNER UNIT (Tables)	9 Months Ended
	Sep. 30, 2024
EARNINGS PER LIMITED PARTNER UNIT
Reconciliation of net income (loss) and EPU calculations	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ 2024 2023 2024 2023 ​ ​ (in thousands, except per unit data) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income attributable to ARLP ​ $ 86,281 ​ $ 153,699 ​ $ 344,525 ​ $ 514,674 ​ Less: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ General partner's interest in net income attributable to ARLP ​ — ​ — ​ — ​ (1,384) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Limited partners' interest in net income attributable to ARLP ​ 86,281 ​ 153,699 ​ 344,525 ​ 513,290 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Less: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Distributions to participating securities ​ (1,616) ​ (2,414) ​ (4,984) ​ (7,242) ​ Undistributed earnings attributable to participating securities ​ — ​ (1,652) ​ (1,378) ​ (6,596) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income attributable to ARLP available to limited partners ​ $ 84,665 ​ $ 149,633 ​ $ 338,163 ​ $ 499,452 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted-average limited partner units outstanding – basic and diluted ​ 128,062 ​ 127,125 ​ 127,932 ​ 127,199 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Earnings per limited partner unit - basic and diluted (1) ​ $ 0.66 ​ $ 1.18 ​ $ 2.64 ​ $ 3.93 ​ (1) Diluted EPU gives effect to all potentially dilutive common units outstanding during the period using the treasury stock method. Diluted EPU excludes all potentially dilutive units calculated under the treasury stock method if their effect is anti-dilutive. The combined total of LTIP, SERP and Directors' Deferred Compensation Plan units of 1,863 and 1,915 for the three and nine months ended September 30, 2024, respectively, and 2,759 and 2,878 for the three and nine months ended September 30, 2023, respectively, were considered anti-dilutive under the treasury stock method .

WORKERS' COMPENSATION AND PNE_2

WORKERS' COMPENSATION AND PNEUMOCONIOSIS (Tables)	9 Months Ended
	Sep. 30, 2024
Black lung benefits:
Reconciliation of changes in workers' compensation liability	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, ​ September 30, ​ ​ ​ 2024 2023 2024 2023 ​ ​ ​ (in thousands) ​ Beginning balance ​ $ 47,194 ​ $ 51,108 ​ $ 47,975 ​ $ 49,452 ​ Changes in accruals ​ 3,658 ​ 3,001 ​ 10,148 ​ 9,071 ​ Payments ​ (3,784) ​ (3,503) ​ (11,278) ​ (10,008) ​ Interest accretion ​ 509 ​ 551 ​ 1,527 ​ 1,652 ​ Valuation loss (gain) (1) ​ — ​ — ​ (795) ​ 990 ​ Ending balance ​ $ 47,577 ​ $ 51,157 ​ $ 47,577 ​ $ 51,157 ​ (1) Our estimate of the liability for the present value of current workers′ compensation benefits is based on our actuarial calculations. Our actuarial calculations are based on a blend of actuarial projection methods and numerous assumptions including claims development patterns, mortality, medical costs and interest rates. The valuation gain in 2024 is due to an increase in the discount rate from 4.66% on December 31, 2023 to 5.18% on June 30, 2024. The valuation loss in 2023 is due to adverse claims development.
Pneumoconiosis benefits
Black lung benefits:
Components of net periodic benefit cost	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ ​ 2024 2023 2024 2023 ​ ​ (in thousands) ​ Service cost ​ $ 864 ​ $ 678 ​ $ 2,583 ​ $ 2,022 Interest cost (1) ​ 1,558 ​ 1,237 ​ 4,674 ​ 3,713 ​ Net amortization (1) ​ 839 ​ 345 ​ 2,517 ​ 1,036 ​ Net periodic benefit cost ​ $ 3,261 ​ $ 2,260 ​ $ 9,774 ​ $ 6,771 ​ (1) Interest cost and net amortization are included in the Other income (expense) line item within our condensed consolidated statements of income.

COMMON UNIT-BASED COMPENSATIO_2

COMMON UNIT-BASED COMPENSATION PLANS (Tables)	9 Months Ended
	Sep. 30, 2024
ARLP LTIP
COMMON UNIT-BASED COMPENSATION PLANS
Summary of non-vested share activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number of units Weighted average grant date fair value per unit Intrinsic value ​ ​ ​ ​ ​ ​ ​ (in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Non-vested grants at January 1, 2024 ​ 2,710,344 ​ $ 10.91 ​ ​ 51,405 ​ Granted (1) 455,574 ​ ​ 19.69 ​ ​ ​ ​ Vested (2) (1,582,422) ​ 6.53 ​ ​ ​ ​ Forfeited (38,204) ​ 16.08 ​ ​ ​ ​ Non-vested grants at September 30, 2024 1,545,292 ​ 17.87 ​ ​ 38,632 ​ (1) The restricted units granted during 2024 have certain minimum-value guarantees per unit, regardless of whether the awards vest. (2) During the nine months ended September 30, 2024, we issued 936,544 unrestricted common units to the LTIP participants. The remaining vested units were settled in cash to satisfy tax withholding.
SERP and Deferred Compensation Plans
COMMON UNIT-BASED COMPENSATION PLANS
Summary of activity in share-based plans	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Number of units Weighted average fair value per unit Intrinsic value ​ ​ ​ ​ ​ ​ ​ (in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Phantom units outstanding as of January 1, 2024 ​ 811,946 ​ $ 20.44 ​ $ 17,197 ​ Granted ​ 79,695 ​ ​ 21.85 ​ ​ ​ ​ Settled (1) (96,873) ​ ​ 23.89 ​ ​ ​ ​ Phantom units outstanding as of September 30, 2024 794,768 ​ 20.78 ​ ​ 19,869 ​ (1) During the nine months ended September 30, 2024, we purchased 54,152 ARLP common units on the open market to settle the account of a participant under the SERP. Units purchased and delivered to the participant were net of units settled in cash to satisfy tax withholding obligations. ​

COMPONENTS OF PENSION PLAN NE_2

COMPONENTS OF PENSION PLAN NET PERIODIC BENEFIT COSTS (Tables)	9 Months Ended
	Sep. 30, 2024
Defined benefit pension plan
Compensation And Pneumoconiosis Benefits
Components of net periodic benefit cost	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ ​ 2024 2023 2024 2023 ​ ​ (in thousands) ​ Interest cost ​ $ 1,289 ​ $ 1,294 ​ $ 3,817 ​ $ 3,885 ​ Expected return on plan assets ​ (1,752) ​ (1,553) ​ (5,278) ​ (4,668) ​ Amortization of prior service cost ​ ​ 47 ​ ​ 47 ​ ​ 140 ​ ​ 140 ​ Amortization of net loss ​ 136 ​ 169 ​ 245 ​ 513 ​ Net periodic benefit credit (1) ​ $ (280) ​ $ (43) ​ $ (1,076) ​ $ (130) ​ (1) Net periodic benefit credit for the Pension Plan is included in the Other income (expense) line item within our condensed consolidated statements of income.

SEGMENT INFORMATION (Tables)

SEGMENT INFORMATION (Tables)	9 Months Ended
	Sep. 30, 2024
SEGMENT INFORMATION
Schedule of reportable segment results	Reportable segment results are presented below. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Coal Operations ​ Royalties ​ Other, ​ ​ ​ ​ ​ Illinois ​ ​ ​ ​ ​ Corporate and ​ ​ ​ ​ Basin Appalachia Oil & Gas Coal ​ Elimination Consolidated ​ ​ (in thousands) Three Months Ended September 30, 2024 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Revenues - Outside (1) ​ $ 356,911 ​ $ 203,164 ​ $ 34,688 ​ $ — ​ $ 18,806 ​ $ 613,569 ​ Revenues - Intercompany ​ ​ — ​ ​ — ​ ​ — ​ ​ 16,647 ​ ​ (16,647) ​ ​ — ​ Total revenues (1) ​ ​ 356,911 ​ ​ 203,164 ​ ​ 34,688 ​ ​ 16,647 ​ ​ 2,159 ​ ​ 613,569 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Segment Adjusted EBITDA Expense (2) ​ 225,498 ​ 157,792 ​ 5,844 ​ 5,589 ​ (1,006) ​ 393,717 ​ Segment Adjusted EBITDA (3) ​ 114,649 ​ 37,518 ​ 28,706 ​ 11,058 ​ 342 ​ 192,273 ​ Capital expenditures (4) ​ 68,512 ​ 32,471 ​ — ​ — ​ 9,315 ​ 110,298 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, 2023 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Revenues - Outside (1) ​ $ 371,633 ​ $ 215,800 ​ $ 36,311 ​ $ — ​ $ 12,777 ​ $ 636,521 ​ Revenues - Intercompany ​ ​ — ​ ​ — ​ ​ — ​ ​ 16,763 ​ ​ (16,763) ​ ​ — ​ Total revenues (1) ​ ​ 371,633 ​ ​ 215,800 ​ ​ 36,311 ​ ​ 16,763 ​ ​ (3,986) ​ ​ 636,521 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Segment Adjusted EBITDA Expense (2) ​ 213,209 ​ 131,997 ​ 3,873 ​ 6,851 ​ (5,524) ​ 350,406 ​ Segment Adjusted EBITDA (3) ​ 132,428 ​ ​ 74,832 ​ ​ 31,366 ​ ​ 9,912 ​ ​ (881) ​ 247,657 ​ Capital expenditures (4) ​ 59,833 ​ 30,304 ​ — ​ — ​ 20,202 ​ 110,339 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2024 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Revenues - Outside (1) ​ $ 1,109,513 ​ $ 589,390 ​ $ 108,470 ​ $ 10 ​ $ 51,233 ​ $ 1,858,616 ​ Revenues - Intercompany ​ ​ — ​ ​ — ​ ​ — ​ ​ 51,933 ​ ​ (51,933) ​ ​ — ​ Total revenues (1) ​ ​ 1,109,513 ​ ​ 589,390 ​ ​ 108,470 ​ ​ 51,943 ​ ​ (700) ​ ​ 1,858,616 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Segment Adjusted EBITDA Expense (2) ​ 674,753 ​ ​ 412,056 ​ ​ 15,419 ​ ​ 18,485 ​ ​ (5,498) ​ 1,115,215 ​ Segment Adjusted EBITDA (3) ​ 372,950 ​ ​ 157,072 ​ ​ 91,366 ​ ​ 33,457 ​ ​ (14) ​ 654,831 ​ Total assets ​ 1,029,389 ​ ​ 534,449 ​ ​ 806,332 ​ ​ 313,044 ​ ​ 348,959 ​ 3,032,173 ​ Capital expenditures (4) ​ 230,618 ​ ​ 91,715 ​ ​ — ​ ​ — ​ ​ 13,253 ​ 335,586 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2023 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Revenues - Outside (1) ​ $ 1,087,431 ​ $ 705,301 ​ $ 105,260 ​ $ — ​ $ 43,287 ​ $ 1,941,279 ​ Revenues - Intercompany ​ ​ — ​ ​ — ​ ​ — ​ ​ 48,843 ​ ​ (48,843) ​ ​ — ​ Total revenues (1) ​ ​ 1,087,431 ​ ​ 705,301 ​ ​ 105,260 ​ ​ 48,843 ​ ​ (5,556) ​ ​ 1,941,279 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Segment Adjusted EBITDA Expense (2) ​ 634,944 ​ ​ 377,115 ​ ​ 11,859 ​ ​ 17,836 ​ ​ (13,618) ​ 1,028,136 ​ Segment Adjusted EBITDA (3) ​ 383,987 ​ ​ 300,955 ​ ​ 90,461 ​ ​ 31,007 ​ ​ 2,560 ​ 808,970 ​ Total assets ​ 882,943 ​ ​ 459,742 ​ ​ 767,415 ​ ​ 319,930 ​ ​ 384,011 ​ 2,814,041 ​ Capital expenditures (4) ​ 179,284 ​ ​ 94,119 ​ ​ — ​ ​ 400 ​ ​ 21,553 ​ 295,356 ​ (1) Revenues included in the Other, Corporate and Elimination column are attributable to intercompany eliminations, which are primarily intercompany coal royalty eliminations, outside revenues at the Matrix Group and awarded digital assets received for our crypto-mining activities. ​ (2) Segment Adjusted EBITDA Expense (a non-GAAP financial measure) includes operating expenses, coal purchases, if applicable, and other income or expense as adjusted to remove certain items from operating expenses that we characterize as unrepresentative of our ongoing operations. Transportation expenses are excluded as these expenses are passed through to our customers and, consequently, we do not realize any gain or loss on transportation revenues. Segment Adjusted EBITDA Expense is used as a supplemental financial measure by our management to assess the operating performance of our segments. Segment Adjusted EBITDA Expense is a key component of Segment Adjusted EBITDA in addition to coal sales, royalty revenues and other revenues. The exclusion of corporate general and administrative expenses from Segment Adjusted EBITDA Expense allows management to focus solely on the evaluation of segment operating performance as it primarily relates to our operating expenses. ​ The following is a reconciliation of Operating expenses (excluding depreciation, depletion and amortization), ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ ​ 2024 2023 2024 2023 ​ ​ (in thousands) ​ Operating expenses (excluding depreciation, depletion and amortization) ​ $ 384,844 ​ $ 339,099 ​ $ 1,100,308 ​ $ 1,012,224 ​ Litigation expense accrual ​ ​ — ​ ​ — ​ ​ (15,250) ​ — ​ Outside coal purchases ​ 8,192 ​ 11,530 ​ 27,912 ​ 15,739 ​ Other expense (income) ​ ​ 681 ​ ​ (223) ​ ​ 2,245 ​ ​ 173 ​ Segment Adjusted EBITDA Expense ​ $ 393,717 ​ $ 350,406 ​ $ 1,115,215 ​ $ 1,028,136 ​ ​ (3) Segment Adjusted EBITDA (a non-GAAP financial measure) is defined as net income attributable to ARLP before net interest expense, income taxes, depreciation, depletion and amortization and general and administrative expenses adjusted for certain items that we characterize as unrepresentative of our ongoing operations. Segment Adjusted EBITDA is a key component of consolidated EBITDA, which is used as a supplemental financial measure by management and by external users of our financial statements such as investors, commercial banks, research analysts and others. We believe that the presentation of EBITDA provides useful information to investors regarding our performance and results of operations because EBITDA, when used in conjunction with related GAAP financial measures, (i) provides additional information about our core operating performance and ability to generate and distribute cash flow, (ii) provides investors with the financial analytical framework upon which we base financial, operational, compensation and planning decisions and (iii) presents a measurement that investors, rating agencies and debt holders have indicated is useful in assessing us and our results of operations. ​ Segment Adjusted EBITDA is also used as a supplemental financial measure by our management for reasons similar to those stated in the previous explanation of EBITDA. In addition, the exclusion of corporate general and administrative expenses from consolidated Segment Adjusted EBITDA allows management to focus solely on the evaluation of segment operating profitability as it relates to our revenues and operating expenses, which are primarily controlled by our segments. ​ The following is a reconciliation of Net income ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ ​ 2024 2023 2024 2023 ​ ​ (in thousands) ​ Net income ​ $ 86,916 ​ $ 155,351 ​ $ 347,992 ​ $ 519,334 ​ Noncontrolling interest ​ ​ (635) ​ ​ (1,652) ​ ​ (3,467) ​ ​ (4,660) ​ Net income attributable to ARLP ​ $ 86,281 ​ $ 153,699 ​ $ 344,525 ​ $ 514,674 ​ General and administrative ​ 21,878 ​ 20,097 ​ 64,569 ​ 61,312 ​ Depreciation, depletion and amortization ​ 72,971 ​ 65,393 ​ 204,974 ​ 199,582 ​ Interest expense, net ​ 7,352 ​ 5,067 ​ 21,018 ​ 21,761 ​ Change in fair value of digital assets ​ ​ (332) ​ ​ — ​ ​ (8,437) ​ ​ — ​ Litigation expense accrual ​ ​ — ​ ​ — ​ ​ 15,250 ​ ​ — ​ Income tax expense ​ 4,123 ​ 3,401 ​ 12,932 ​ 11,641 ​ Consolidated Segment Adjusted EBITDA ​ $ 192,273 ​ $ 247,657 ​ $ 654,831 ​ $ 808,970 ​ ​ (4) Capital expenditures exclude $72.3 million paid for the JC Resources Acquisition for the nine months ended September 30, 2023, $10.5 million and $10.0 million paid towards oil & gas reserve acquisitions for the three months ended September 30, 2024 and 2023, respectively, and $15.2 million and $13.9 million paid towards oil & gas reserve acquisitions for the nine months ended September 30, 2024 and 2023, respectively (See Note 3 – Acquisitions) .
Reconciliation of consolidated Segment Adjusted EBITDA Expense to operating expenses (excluding depreciation, depletion and amortization)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ ​ 2024 2023 2024 2023 ​ ​ (in thousands) ​ Operating expenses (excluding depreciation, depletion and amortization) ​ $ 384,844 ​ $ 339,099 ​ $ 1,100,308 ​ $ 1,012,224 ​ Litigation expense accrual ​ ​ — ​ ​ — ​ ​ (15,250) ​ — ​ Outside coal purchases ​ 8,192 ​ 11,530 ​ 27,912 ​ 15,739 ​ Other expense (income) ​ ​ 681 ​ ​ (223) ​ ​ 2,245 ​ ​ 173 ​ Segment Adjusted EBITDA Expense ​ $ 393,717 ​ $ 350,406 ​ $ 1,115,215 ​ $ 1,028,136 ​
Reconciliation of consolidated Segment Adjusted EBITDA to net income	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ ​ 2024 2023 2024 2023 ​ ​ (in thousands) ​ Net income ​ $ 86,916 ​ $ 155,351 ​ $ 347,992 ​ $ 519,334 ​ Noncontrolling interest ​ ​ (635) ​ ​ (1,652) ​ ​ (3,467) ​ ​ (4,660) ​ Net income attributable to ARLP ​ $ 86,281 ​ $ 153,699 ​ $ 344,525 ​ $ 514,674 ​ General and administrative ​ 21,878 ​ 20,097 ​ 64,569 ​ 61,312 ​ Depreciation, depletion and amortization ​ 72,971 ​ 65,393 ​ 204,974 ​ 199,582 ​ Interest expense, net ​ 7,352 ​ 5,067 ​ 21,018 ​ 21,761 ​ Change in fair value of digital assets ​ ​ (332) ​ ​ — ​ ​ (8,437) ​ ​ — ​ Litigation expense accrual ​ ​ — ​ ​ — ​ ​ 15,250 ​ ​ — ​ Income tax expense ​ 4,123 ​ 3,401 ​ 12,932 ​ 11,641 ​ Consolidated Segment Adjusted EBITDA ​ $ 192,273 ​ $ 247,657 ​ $ 654,831 ​ $ 808,970 ​

NEW ACCOUNTING STANDARDS (Detai

NEW ACCOUNTING STANDARDS (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Jun. 30, 2024	Dec. 31, 2023
New accounting pronouncements
Fair value digital asset	$ 28,959	$ 28,335	$ 15,811
ASU 2023-08 - Crypto Assets | Cumulative Effect, Period of Adoption, Adjustment
New accounting pronouncements
Fair value digital asset			$ 6,200

ACQUISITIONS - Asset acquisitio

ACQUISITIONS - Asset acquisition (Details) - USD ($) $ in Millions	Sep. 30, 2024	Feb. 19, 2024	Jan. 27, 2023
Acquisition Agreement
Asset acquisition
Funding commitment		$ 25	$ 35
Mineral interests in proved properties	$ 5.1
Mineral interests in unproved properties	7.8
Miscellaneous Acquisitions
Asset acquisition
Mineral interests in proved properties	0.7
Mineral interests in unproved properties	$ 1.6

CONTINGENCIES (Details)

CONTINGENCIES (Details) - USD ($) $ in Millions	1 Months Ended
	Apr. 30, 2024	Sep. 30, 2024
CONTINGENCIES
Settlement awarded to other party	$ 15.3
Settlement accrual		$ 15.3

INVENTORIES (Details)

INVENTORIES (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Inventory
Coal	$ 95,333	$ 56,549
Finished goods (net of reserve for obsolescence)	3,812	3,908
Work in process	580	791
Raw materials	1,838	2,144
Total operating inventories, net	101,563	63,392
Supplies (net of reserve for obsolescence)	75,940	64,164
Total inventories, net	177,503	127,556
Reduce inventory carrying value to market	5,900
Manufactured goods
Inventory
Reserve for obsolescence	723	728
Supplies
Inventory
Reserve for obsolescence	$ 8,036	$ 7,439

DIGITAL ASSETS - Balance sheet

DIGITAL ASSETS - Balance sheet (Details) $ in Thousands	Sep. 30, 2024 USD ($) instrument	Jun. 30, 2024 USD ($)	Dec. 31, 2023 USD ($)
Crypto Assets
Cost Basis	$ 16,327
Fair Value	$ 28,959	$ 28,335	$ 15,811
Bitcoin
Crypto Assets
Units | instrument	457
Cost Basis	$ 16,327
Fair Value	$ 28,959

DIGITAL ASSETS - Reconciliation

DIGITAL ASSETS - Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2024
Digital assets reconciliation
Digital asset, Beginning Balance	$ 28,335	$ 15,811
Additions	1,709	7,848
Dispositions	(1,417)	(3,137)
Fair value gains (losses)	332	8,437
Digital asset, Ending Balance	28,959	28,959
Realized gains on disposal of digital assets	$ 1,000	$ 2,100

DIGITAL ASSETS - Adoption (Deta

DIGITAL ASSETS - Adoption (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Jun. 30, 2024	Dec. 31, 2023
New accounting pronouncements
Fair value digital asset	$ 28,959	$ 28,335	$ 15,811
ASU 2023-08 - Crypto Assets | Cumulative Effect, Period of Adoption, Adjustment
New accounting pronouncements
Fair value digital asset			$ 6,200

FAIR VALUE MEASUREMENTS (Detail

FAIR VALUE MEASUREMENTS (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Jun. 30, 2024	Dec. 31, 2023
FAIR VALUE MEASUREMENTS
Fair Value	$ 28,959	$ 28,335	$ 15,811
Estimated fair value | Level 2
FAIR VALUE MEASUREMENTS
Long-term debt	528,540		347,116
Estimated fair value | Recurring | Level 1
FAIR VALUE MEASUREMENTS
Fair Value	28,959
Carrying Value
FAIR VALUE MEASUREMENTS
Long-term debt	496,958		$ 347,584
Carrying Value | Recurring
FAIR VALUE MEASUREMENTS
Fair Value	$ 28,959

LONG-TERM DEBT - Components (De

LONG-TERM DEBT - Components (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Jun. 12, 2024	Dec. 31, 2023	Jan. 13, 2023	Apr. 24, 2017
Principal
Aggregate maturities of long-term debt	$ 496,958		$ 347,584
Less current maturities	(26,669)		(20,789)
Total long-term debt	470,289		326,795
Unamortized Discount and Debt Issuance Costs
Unamortized debt issuance costs including current and non-current	(18,367)		(10,425)
Less current maturities	4,394		451
Total unamortized debt issuance costs	(13,973)		(9,974)
Revolving credit facility
Unamortized Discount and Debt Issuance Costs
Unamortized debt issuance costs including current and non-current	(7,788)		(8,118)
Term loan
Principal
Aggregate maturities of long-term debt	49,219		60,938
Unamortized Discount and Debt Issuance Costs
Unamortized debt issuance costs including current and non-current	(1,375)		(1,416)
Interest rate (as a percent)				6.25%
2029 Senior Notes
Principal
Aggregate maturities of long-term debt	400,000
Unamortized Discount and Debt Issuance Costs
Unamortized debt issuance costs including current and non-current	$ (9,204)
Interest rate (as a percent)	8.625%	8.625%
7.5% Senior notes due 2025
Principal
Aggregate maturities of long-term debt			284,607
Unamortized Discount and Debt Issuance Costs
Unamortized debt issuance costs including current and non-current			(891)
Interest rate (as a percent)	7.50%				7.50%
June 2020 equipment financing
Principal
Aggregate maturities of long-term debt			$ 2,039
February 2024 equipment financing
Principal
Aggregate maturities of long-term debt	$ 47,739

LONG-TERM DEBT - Credit Facilit

LONG-TERM DEBT - Credit Facility (Details) - USD ($) $ in Millions		9 Months Ended
	Jan. 13, 2023	Sep. 30, 2024	Jun. 12, 2024
Credit Agreement
Long-Term Debt
Maximum borrowing capacity	$ 425
Increase of maximum borrowing capacity	100
Minimum liquidity to extend maturity	$ 200
Letters of credit outstanding		$ 41
Debt available for borrowing		$ 384
Annual commitment fee percentage, undrawn portion		0.50%
Minimum debt to cash flow ratio for restriction to apply on cash distribution	1
ARLP debt arrangements requirements, period over which the ratios are required to be maintained		12 months
Credit Agreement | Minimum
Long-Term Debt
Interest coverage ratio	1
Actual cash flow to interest expense ratio for trailing twelve months		1
Credit Agreement | Maximum
Long-Term Debt
Interest coverage ratio	3
Actual cash flow to interest expense ratio for trailing twelve months		43.19
Credit Agreement | Overnight Bank Funding Rate
Long-Term Debt
Basis spread for variable interest rate (as a percent)	0.50%
Credit Agreement | Daily Simple Secured Overnight Financing Rate
Long-Term Debt
Basis spread for variable interest rate (as a percent)	1%
Credit Agreement | Alliance Coal | Minimum
Long-Term Debt
ARLP debt arrangements requirements, debt to cash flow ratio	1
Actual debt to cash flow ratio for trailing twelve months		0.17
Credit Agreement | Alliance Coal | Maximum
Long-Term Debt
ARLP debt arrangements requirements, debt to cash flow ratio	1.5	1
Credit Agreement | Alliance Coal and Intermediate Partnership | Minimum
Long-Term Debt
ARLP debt arrangements requirements, debt to cash flow ratio	1
Actual debt to cash flow ratio for trailing twelve months		0.84
Credit Agreement | Alliance Coal and Intermediate Partnership | Maximum
Long-Term Debt
ARLP debt arrangements requirements, debt to cash flow ratio	2.5
Actual debt to cash flow ratio for trailing twelve months		1
Swingline subfacility
Long-Term Debt
Maximum borrowing capacity	$ 15
Term loan
Long-Term Debt
Maximum borrowing term loan	$ 75
Interest rate (as a percent)	6.25%
Effective interest rate (as a percent)		8.20%
2029 Senior Notes
Long-Term Debt
Interest rate (as a percent)		8.625%	8.625%

LONG-TERM DEBT - Senior Notes (

LONG-TERM DEBT - Senior Notes (Details) - USD ($) $ in Millions	Jun. 12, 2024	Apr. 24, 2017	Sep. 30, 2024
2029 Senior Notes
Issuance of Senior Notes
Principal amount	$ 400
Term	5 years
Interest rate (as a percent)	8.625%		8.625%
2029 Senior Notes | Scenario One
Issuance of Senior Notes
Maximum redeemable debt (as a percent)	35%
Redemption price to principal (as a percent)	108.625%
2029 Senior Notes | Scenario Two
Issuance of Senior Notes
Maximum redeemable debt (as a percent)	40%
Redemption price to principal (as a percent)	108.625%
7.5% Senior notes due 2025
Issuance of Senior Notes
Principal amount		$ 400
Term		8 years
Interest rate (as a percent)		7.50%	7.50%

LONG-TERM DEBT - Securitization

LONG-TERM DEBT - Securitization Facility (Details) - Securitization facility $ in Millions	Sep. 30, 2024 USD ($)
Long-Term Debt
Maximum borrowing capacity	$ 90
Letters of credit outstanding	11.7
Debt available for borrowing	$ 78.3

LONG-TERM DEBT - Equipment fina

LONG-TERM DEBT - Equipment financing and other (Details) - USD ($) $ in Millions	Feb. 28, 2024	Jun. 05, 2020
June 2020 equipment financing
Long-Term Debt
Principal amount		$ 14.7
Term		48 months
Effective interest rate (as a percent)		6.10%
February 2024 equipment financing
Long-Term Debt
Principal amount	$ 54.6
Term	48 months
Effective interest rate (as a percent)	8.29%

INCOME TAXES - Components (Deta

INCOME TAXES - Components (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Current:
Federal	$ 4,567	$ 5,429	$ 13,791	$ 13,676
State	320	373	975	946
Total current income tax expense	4,887	5,802	14,766	14,622
Deferred:
Federal	(712)	(2,077)	(1,678)	(2,598)
State	(52)	(324)	(156)	(383)
Total deferred income tax expense	(764)	(2,401)	(1,834)	(2,981)
Income tax expense	$ 4,123	$ 3,401	$ 12,932	$ 11,641

VARIABLE INTEREST ENTITIES - Al

VARIABLE INTEREST ENTITIES - AllDale (Detail)	9 Months Ended
	Sep. 30, 2024
Cavalier Minerals
Equity Investments
Ownership interest in VIE (as a percent)	96%
Cavalier Minerals | Bluegrass Minerals
Equity Investments
Distributions to be received (as a percent)	25%
Noncontrolling ownership interest (as a percent)	4%
AllDale III | Cavalier Minerals
Equity Investments
Ownership percentage by limited partners	72%
AllDale III
Equity Investments
Distribution after hurdles (as a percent)	25%
Specified internal rate of return (as a percent)	10%
Percentage of available cash distributed	125%
VIE, Primary Beneficiary | AllDale I and II | AllDale III
Equity Investments
Ownership percentage by limited partners	97%
VIE, Primary Beneficiary | AllDale I and II | General Partners' Capital
Equity Investments
Distributions to be received (as a percent)	20%
VIE, Primary Beneficiary | AllDale I and II | Limited Partners' Capital
Equity Investments
Distributions to be received (as a percent)	80%
VIE, Not Primary Beneficiary | AllDale III | AllDale III
Equity Investments
Ownership percentage by limited partners	13.90%

VARIABLE INTEREST ENTITIES - Ba

VARIABLE INTEREST ENTITIES - Bal Sheet (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Balance Sheet Related Disclosures
Cash and cash equivalents	$ 195,429	$ 59,813
Trade receivables	198,647	282,622
Total property, plant and equipment, net	2,161,591	2,022,663
Accounts payable	(115,719)	(108,269)
Accrued taxes other than income taxes	(21,336)	(21,007)
AllDale I and II
Balance Sheet Related Disclosures
Cash and cash equivalents	6,040	4,690
Trade receivables	12,581	16,058
Total property, plant and equipment, net	377,236	389,767
Accounts payable	(253)	(175)
Accrued taxes other than income taxes	$ (682)	$ (958)

VARIABLE INTEREST ENTITIES - In

VARIABLE INTEREST ENTITIES - Investments (Detail) - USD ($) $ in Thousands			3 Months Ended		9 Months Ended
	Jun. 02, 2022	Apr. 05, 2022	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Equity Investments
Contributions to equity method investments					$ 1,398	$ 2,257
Francis Renewable Energy
Equity Investments
Contributions to equity method investments		$ 20,000
Francis Renewable Energy | Francis Renewable Energy
Equity Investments
Ownership percentage by limited partners					16.70%
NGP ET IV
Equity Investments
Contributions to equity method investments			$ 108	$ 923	$ 1,398	$ 2,257
Funding commitment	$ 25,000
Contributions to investee to date			$ 8,000		$ 8,000
NGP ET IV | NGP ET IV
Equity Investments
Ownership percentage by limited partners	3.60%

EQUITY INVESTMENTS - Equity met

EQUITY INVESTMENTS - Equity method (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	Apr. 05, 2022	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Equity Investments
Beginning balance				$ 46,503
Contributions				1,398	$ 2,257
Equity method investment income (loss)		$ (2,327)	$ (1,842)	(3,032)	(3,784)
Other income (expense)		(681)	223	(2,245)	(173)
Ending balance		36,902		36,902
AllDale III
Equity Investments
Beginning balance		23,218	24,451	23,933	25,284
Equity method investment income (loss)		496	578	1,781	1,719
Distributions received		(849)	(904)	(2,849)	(2,878)
Ending balance		22,865	24,125	22,865	24,125
Francis Renewable Energy
Equity Investments
Beginning balance		14,518	17,380	16,487	20,000
Contributions	$ 20,000
Equity method investment income (loss)		(2,487)	(2,435)	(4,456)	(5,055)
Change in our share of Francis' net assets		(5,118)		(5,118)
Ending balance		6,913	14,945	6,913	14,945
NGP ET IV
Equity Investments
Beginning balance		7,352	4,958	6,083	4,087
Contributions		108	923	1,398	2,257
Equity method investment income (loss)		(336)	15	(357)	(448)
Ending balance		$ 7,124	$ 5,896	$ 7,124	$ 5,896

EQUITY INVESTMENTS - Non-equity

EQUITY INVESTMENTS - Non-equity method (Details) - USD ($) $ in Thousands		9 Months Ended	12 Months Ended
	Sep. 08, 2023	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2024	Dec. 31, 2023	Aug. 22, 2023
Equity securities without readily determinable fair value
Equity securities				$ 92,541	$ 92,541
Contributions		$ 49,560
Infinitum
Equity securities without readily determinable fair value
Contributions	$ 24,600		$ 42,000
Ascend
Equity securities without readily determinable fair value
Equity securities						$ 25,000

PARTNERS' CAPITAL - Distributio

PARTNERS' CAPITAL - Distributions (Details) - USD ($) $ / shares in Units, $ in Thousands									9 Months Ended		12 Months Ended
	Nov. 14, 2024	Aug. 14, 2024	May 15, 2024	Feb. 14, 2024	Nov. 14, 2023	Aug. 14, 2023	May 15, 2023	Feb. 14, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
PARTNERS' CAPITAL.
Quarterly distribution paid (in dollars per unit)	$ 0.70	$ 0.70	$ 0.70	$ 0.70	$ 0.70	$ 0.70	$ 0.70	$ 0.70	$ 2.80		$ 2.80
Total Cash Distribution		$ 90,725	$ 90,736	$ 91,246	$ 90,812	$ 90,899	$ 90,930	$ 91,938	$ 272,707	$ 273,767	$ 364,579

PARTNERS' CAPITAL - Narrative (

PARTNERS' CAPITAL - Narrative (Details) - Limited Partners' Capital - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	9 Months Ended
	Jan. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
Partners' capital
Increase in authorization amount	$ 93.5
Repurchase and retire authorization	$ 100
Number of units retired		0	929,842
Treasury units retired			$ 19.4
Repurchase price (in dollars per unit)			$ 20.90
Aggregate
Partners' capital
Number of units retired		6,390,446
Treasury units retired		$ 112.9
Repurchase price (in dollars per unit)		$ 17.67

PARTNERS' CAPITAL - Change (Det

PARTNERS' CAPITAL - Change (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
Increase (decrease) in Partners' Capital
Balance at beginning of period	$ 1,934,118	$ 1,921,404	$ 1,858,597	$ 1,786,757	$ 1,707,161	$ 1,708,026	$ 1,858,597	$ 1,708,026
Balance at beginning of period (in units)			127,125,437				127,125,437
Comprehensive income (loss):
Net income	86,916	101,509	$ 159,567	155,351	171,305	192,678	$ 347,992	519,334
Actuarially determined long-term liability adjustments	1,022	957	923	561	563	565	2,902	1,689
COMPREHENSIVE INCOME	87,938	102,466	160,490	155,912	171,868	193,243	350,894	521,023
Settlement of deferred compensation plans	(2,252)		(13,292)		(1,014)	(9,320)
Purchase of units under unit repurchase program					(1,223)	(18,209)
Common unit-based compensation	3,032	2,926	2,604	3,239	3,121	2,830
Distributions on deferred common unit-based compensation	(1,082)	(1,091)	(2,261)	(1,911)	(1,895)	(2,901)
Distributions from consolidated company to noncontrolling interest	(1,883)	(1,942)	(1,981)	(2,081)	(2,226)	(2,288)
JC Resources acquisition						(72,250)
Cash retained by JC Resources in acquisition						(2,933)
Other	(5,118)
Distributions to Partners	(89,643)	(89,645)	(88,985)	(88,988)	(89,035)	(89,037)
Balance at end of period	$ 1,925,110	1,934,118	1,921,404	1,852,928	1,786,757	1,707,161	$ 1,925,110	1,852,928
Balance at end of period (in units)	128,061,981						128,061,981
Cumulative Effect, Period of Adoption, Adjustment
Increase (decrease) in Partners' Capital
Balance at beginning of period			6,232				$ 6,232
Accumulated Other Comprehensive Income (Loss)
Increase (decrease) in Partners' Capital
Balance at beginning of period	$ (59,645)	(60,602)	(61,525)	(39,926)	(40,489)	(41,054)	(61,525)	(41,054)
Comprehensive income (loss):
Actuarially determined long-term liability adjustments	1,022	957	923	561	563	565
Balance at end of period	(58,623)	(59,645)	(60,602)	(39,365)	(39,926)	(40,489)	(58,623)	(39,365)
Noncontrolling Interest
Increase (decrease) in Partners' Capital
Balance at beginning of period	23,004	23,624	24,095	25,001	25,712	26,507	24,095	26,507
Comprehensive income (loss):
Net income	635	1,322	1,510	1,652	1,515	1,493
Distributions from consolidated company to noncontrolling interest	(1,883)	(1,942)	(1,981)	(2,081)	(2,226)	(2,288)
Balance at end of period	21,756	23,004	23,624	24,572	25,001	25,712	21,756	24,572
Limited Partners' Capital
Increase (decrease) in Partners' Capital
Balance at beginning of period	$ 1,970,759	$ 1,958,382	$ 1,896,027	$ 1,801,682	$ 1,721,938	$ 1,656,025	$ 1,896,027	$ 1,656,025
Balance at beginning of period (in units)	128,061,981	128,061,981	127,125,437	127,125,437	127,195,219	127,195,219	127,125,437	127,195,219
Comprehensive income (loss):
Net income	$ 86,281	$ 100,187	$ 158,057	$ 153,699	$ 169,790	$ 189,801
Settlement of deferred compensation plans	(2,252)		$ (13,292)		(1,014)	$ (9,320)
Settlement of deferred common unit- based compensation plans (in units)			936,544			860,060
Purchase of units under unit repurchase program					$ (1,223)	$ (18,209)
Purchase of units under unit repurchase program (in units)					(69,782)	(860,060)
Common unit-based compensation	3,032	2,926	$ 2,604	3,239	$ 3,121	$ 2,830
Distributions on deferred common unit-based compensation	(1,082)	(1,091)	(2,261)	(1,911)	(1,895)	(2,901)
JC Resources acquisition						(7,251)
Other	(5,118)
Distributions to Partners	(89,643)	(89,645)	(88,985)	(88,988)	(89,035)	(89,037)
Balance at end of period	$ 1,961,977	$ 1,970,759	$ 1,958,382	$ 1,867,721	$ 1,801,682	$ 1,721,938	$ 1,961,977	$ 1,867,721
Balance at end of period (in units)	128,061,981	128,061,981	128,061,981	127,125,437	127,125,437	127,195,219	128,061,981	127,125,437
Limited Partners' Capital | Cumulative Effect, Period of Adoption, Adjustment
Increase (decrease) in Partners' Capital
Balance at beginning of period			$ 6,232				$ 6,232
General Partners' Capital
Increase (decrease) in Partners' Capital
Balance at beginning of period						$ 66,548		$ 66,548
Comprehensive income (loss):
Net income						1,384
JC Resources acquisition						(64,999)
Cash retained by JC Resources in acquisition						$ (2,933)

REVENUE FROM CONTRACTS WITH C_3

REVENUE FROM CONTRACTS WITH CUSTOMERS - Disaggregation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Disaggregation of revenues
Revenues	$ 613,569	$ 636,521	$ 1,858,616	$ 1,941,279
Coal sales
Disaggregation of revenues
Revenues	532,647	549,123	1,607,185	1,688,238
Oil & gas royalties
Disaggregation of revenues
Revenues	34,448	34,125	107,907	101,709
Transportation
Disaggregation of revenues
Revenues	24,617	34,964	82,071	95,729
Other revenues
Disaggregation of revenues
Revenues	21,857	18,309	61,453	55,603
Coal Royalties
Disaggregation of revenues
Revenues	16,647	16,763	51,943	48,843
Coal Royalties | Coal royalties
Disaggregation of revenues
Revenues	16,647
Operating segments | Illinois Basin Coal
Disaggregation of revenues
Revenues	356,911	371,633	1,109,513	1,087,431
Operating segments | Illinois Basin Coal | Coal sales
Disaggregation of revenues
Revenues	337,816	342,744	1,040,419	1,011,467
Operating segments | Illinois Basin Coal | Transportation
Disaggregation of revenues
Revenues	16,764	25,992	61,810	68,498
Operating segments | Illinois Basin Coal | Other revenues
Disaggregation of revenues
Revenues	2,331	2,897	7,284	7,466
Operating segments | Appalachia Coal
Disaggregation of revenues
Revenues	203,164	215,800	589,390	705,301
Operating segments | Appalachia Coal | Coal sales
Disaggregation of revenues
Revenues	194,831	206,379	566,766	676,771
Operating segments | Appalachia Coal | Transportation
Disaggregation of revenues
Revenues	7,853	8,972	20,261	27,231
Operating segments | Appalachia Coal | Other revenues
Disaggregation of revenues
Revenues	480	449	2,363	1,299
Operating segments | Oil & Gas Royalties
Disaggregation of revenues
Revenues	34,688	36,311	108,470	105,260
Operating segments | Oil & Gas Royalties | Oil & gas royalties
Disaggregation of revenues
Revenues	34,448	34,125	107,907	101,709
Operating segments | Oil & Gas Royalties | Other revenues
Disaggregation of revenues
Revenues	240	2,186	563	3,551
Operating segments | Coal Royalties
Disaggregation of revenues
Revenues			10
Operating segments | Coal Royalties | Coal royalties
Disaggregation of revenues
Revenues		16,763	51,933	48,843
Operating segments | Coal Royalties | Other revenues
Disaggregation of revenues
Revenues			10
Other, Corporate and Elimination
Disaggregation of revenues
Revenues	2,159	(3,986)	(700)	(5,556)
Other, Corporate and Elimination | Coal royalties
Disaggregation of revenues
Revenues	(16,647)	(16,763)	(51,933)	(48,843)
Other, Corporate and Elimination | Other revenues
Disaggregation of revenues
Revenues	18,806	12,777	51,233	43,287
Elimination
Disaggregation of revenues
Revenues	(16,647)	(16,763)	(51,933)	(48,843)
Elimination | Coal Royalties
Disaggregation of revenues
Revenues	$ 16,647	$ 16,763	$ 51,933	$ 48,843

REVENUE FROM CONTRACTS WITH C_4

REVENUE FROM CONTRACTS WITH CUSTOMERS - Supply contracts (Details) $ in Thousands	Sep. 30, 2024 USD ($)
Performance obligations unsatisfied or partially unsatisfied
Total	$ 2,565,571
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-10-01
Performance obligations unsatisfied or partially unsatisfied
Total	$ 564,369
Expected timing of satisfaction period	3 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Performance obligations unsatisfied or partially unsatisfied
Total	$ 1,100,572
Expected timing of satisfaction period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Performance obligations unsatisfied or partially unsatisfied
Total	$ 515,425
Expected timing of satisfaction period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01
Performance obligations unsatisfied or partially unsatisfied
Total	$ 385,205
Expected timing of satisfaction period	1 year
Illinois Basin Coal
Performance obligations unsatisfied or partially unsatisfied
Total	$ 1,800,535
Illinois Basin Coal | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-10-01
Performance obligations unsatisfied or partially unsatisfied
Total	$ 361,441
Expected timing of satisfaction period	3 months
Illinois Basin Coal | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Performance obligations unsatisfied or partially unsatisfied
Total	$ 668,579
Expected timing of satisfaction period	1 year
Illinois Basin Coal | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Performance obligations unsatisfied or partially unsatisfied
Total	$ 415,415
Expected timing of satisfaction period	1 year
Illinois Basin Coal | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01
Performance obligations unsatisfied or partially unsatisfied
Total	$ 355,100
Expected timing of satisfaction period	1 year
Appalachia Coal
Performance obligations unsatisfied or partially unsatisfied
Total	$ 765,036
Appalachia Coal | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-10-01
Performance obligations unsatisfied or partially unsatisfied
Total	$ 202,928
Expected timing of satisfaction period	3 months
Appalachia Coal | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Performance obligations unsatisfied or partially unsatisfied
Total	$ 431,993
Expected timing of satisfaction period	1 year
Appalachia Coal | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Performance obligations unsatisfied or partially unsatisfied
Total	$ 100,010
Expected timing of satisfaction period	1 year
Appalachia Coal | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01
Performance obligations unsatisfied or partially unsatisfied
Total	$ 30,105
Expected timing of satisfaction period	1 year

EARNINGS PER LIMITED PARTNER _3

EARNINGS PER LIMITED PARTNER UNIT (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
EARNINGS PER LIMITED PARTNER UNIT
NET INCOME ATTRIBUTABLE TO ARLP	$ 86,281	$ 153,699	$ 344,525	$ 514,674
General partner's interest in net income attributable to ARLP				(1,384)
Limited partners' interest in net income attributable to ARLP	86,281	153,699	344,525	513,290
Distributions to participating securities	(1,616)	(2,414)	(4,984)	(7,242)
Undistributed earnings attributable to participating securities		(1,652)	(1,378)	(6,596)
Net income (loss) attributable to ARLP available to limited partners	$ 84,665	$ 149,633	$ 338,163	$ 499,452
Weighted-average limited partner units outstanding - basic (in units)	128,061,981	127,125,437	127,932,095	127,198,805
Weighted-average limited partner units outstanding - diluted (in units)	128,062,000	127,125,000	127,932,000	127,199,000
Earnings per limited partner unit - basic (in dollars per unit)	$ 0.66	$ 1.18	$ 2.64	$ 3.93
Earnings per limited partner unit - diluted (in dollars per unit)	$ 0.66	$ 1.18	$ 2.64	$ 3.93
Anti-dilutive under the treasury stock method (in units)	1,863,000	2,759,000	1,915,000	2,878,000

WORKERS' COMPENSATION AND PNE_3

WORKERS' COMPENSATION AND PNEUMOCONIOSIS - Roll forward (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Reconciliation of changes in the workers' compensation liability
Beginning balance	$ 47,194	$ 51,108	$ 47,975	$ 49,452	$ 49,452
Changes in accruals	3,658	3,001	10,148	9,071
Payments	(3,784)	(3,503)	(11,278)	(10,008)
Interest accretion	509	551	1,527	1,652
Valuation loss			(795)	990
Ending balance	47,577	$ 51,157	$ 47,577	$ 51,157	$ 47,975
Estimated present value of future obligations and other information
Workers' compensation discount rate			5.18%		4.66%
Other long-term assets
Estimated present value of future obligations and other information
Receivables for traumatic injury claims	$ 4,100		$ 4,100

WORKERS' COMPENSATION AND PNE_4

WORKERS' COMPENSATION AND PNEUMOCONIOSIS - Benefit cost (Details) - Pneumoconiosis benefits - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Black lung benefits:
Service cost	$ 864	$ 678	$ 2,583	$ 2,022
Interest cost	$ 1,558	$ 1,237	$ 4,674	$ 3,713
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Interest Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)
Net amortization	$ 839	$ 345	$ 2,517	$ 1,036
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Amortization of Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)
Net periodic benefit cost	$ 3,261	$ 2,260	$ 9,774	$ 6,771

COMMON UNIT-BASED COMPENSATIO_3

COMMON UNIT-BASED COMPENSATION PLANS - LTIP Grants (Details) - ARLP LTIP - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Number of units
Balance at the beginning of the period (in units)	2,710,344
Granted (in units)	455,574
Vested (in units)	(1,582,422)
Forfeited (in units)	(38,204)
Balance at the end of the period (in units)	1,545,292
Weighted average grant date fair value per unit
Balance at the beginning of the period (in dollars per unit)	$ 10.91
Granted (in dollars per unit)	19.69
Vested (in dollars per unit)	6.53
Forfeited (in dollars per unit)	16.08
Balance at the end of the period (in dollars per unit)	$ 17.87
Intrinsic value (in dollars)
Intrinsic value of outstanding grants (in dollars)	$ 38,632	$ 51,405
Other information
Common units issued	936,544

COMMON UNIT-BASED COMPENSATIO_4

COMMON UNIT-BASED COMPENSATION PLANS - LTIP Other (Details) - ARLP LTIP - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Other information
Unit-based compensation expense	$ 2.4	$ 2.7	$ 6.8	$ 7.7
Total unit-based obligation recorded	15.9		15.9
Unrecognized compensation expense (in dollars)	$ 11.7		$ 11.7
Weighted-average period for recognition of expense			1 year 1 month 6 days

COMMON UNIT-BASED COMPENSATIO_5

COMMON UNIT-BASED COMPENSATION PLANS - SERP and Directors (Details) - SERP and Deferred Compensation Plans - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Number of units
Balance at the beginning of the period (in units)			811,946
Granted (in units)			79,695
Settled (in units)			(96,873)
Balance at the end of the period (in units)	794,768		794,768
Weighted average grant date fair value per unit
Balance at the beginning of the period (in dollars per unit)			$ 20.44
Granted (in dollars per unit)			21.85
Settled (in dollars per unit)			23.89
Balance at the end of the period (in dollars per unit)	$ 20.78		$ 20.78
Intrinsic value (in dollars)
Intrinsic value of outstanding grants (in dollars)	$ 19,869		$ 19,869		$ 17,197
Other information
Purchased for awards (in shares)			54,152
Unit-based compensation expense	700	$ 600	$ 2,000	$ 1,800
Total unit-based obligation recorded	$ 16,500		$ 16,500

COMPONENTS OF PENSION PLAN NE_3

COMPONENTS OF PENSION PLAN NET PERIODIC BENEFIT COSTS (Details) - Pension Plan - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Components of net periodic benefit cost:
Interest cost	$ 1,289	$ 1,294	$ 3,817	$ 3,885
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Interest Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)
Expected return on plan assets	$ (1,752)	$ (1,553)	$ (5,278)	$ (4,668)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Expected Return (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)
Amortization of prior service cost	$ 47	$ 47	$ 140	$ 140
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Amortization of Prior Service Cost (Credit), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)
Amortization of net loss	$ 136	$ 169	$ 245	$ 513
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Amortization of Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)	Other Nonoperating Income (Expense)
Net periodic benefit cost	$ (280)	$ (43)	$ (1,076)	$ (130)

SEGMENT INFORMATION - General (

SEGMENT INFORMATION - General (Details)	9 Months Ended
	Sep. 30, 2024 segment
SEGMENT INFORMATION
Number of reportable segments	4
Number of coal reportable segments	2
Number of mining complex	7
Percentage of coal sold by coal operations' mines leased from coal royalties entities	63%

SEGMENT INFORMATION - Segment R

SEGMENT INFORMATION - Segment Results (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Reportable segment results
Revenues	$ 613,569	$ 636,521	$ 1,858,616	$ 1,941,279
Segment Adjusted EBITDA Expense	393,717	350,406	1,115,215	1,028,136
Segment Adjusted EBITDA	192,273	247,657	654,831	808,970
Total assets	3,032,173	2,814,041	3,032,173	2,814,041	$ 2,788,426
Capital expenditures	110,298	110,339	335,586	295,356
Other revenues
Reportable segment results
Revenues	21,857	18,309	61,453	55,603
Coal Royalties
Reportable segment results
Revenues	16,647	16,763	51,943	48,843
Operating segments | Illinois Basin Coal
Reportable segment results
Revenues	356,911	371,633	1,109,513	1,087,431
Segment Adjusted EBITDA Expense	225,498	213,209	674,753	634,944
Segment Adjusted EBITDA	114,649	132,428	372,950	383,987
Total assets	1,029,389	882,943	1,029,389	882,943
Capital expenditures	68,512	59,833	230,618	179,284
Operating segments | Illinois Basin Coal | Other revenues
Reportable segment results
Revenues	2,331	2,897	7,284	7,466
Operating segments | Appalachia Coal
Reportable segment results
Revenues	203,164	215,800	589,390	705,301
Segment Adjusted EBITDA Expense	157,792	131,997	412,056	377,115
Segment Adjusted EBITDA	37,518	74,832	157,072	300,955
Total assets	534,449	459,742	534,449	459,742
Capital expenditures	32,471	30,304	91,715	94,119
Operating segments | Appalachia Coal | Other revenues
Reportable segment results
Revenues	480	449	2,363	1,299
Operating segments | Oil & Gas Royalties
Reportable segment results
Revenues	34,688	36,311	108,470	105,260
Segment Adjusted EBITDA Expense	5,844	3,873	15,419	11,859
Segment Adjusted EBITDA	28,706	31,366	91,366	90,461
Total assets	806,332	767,415	806,332	767,415
Operating segments | Oil & Gas Royalties | Other revenues
Reportable segment results
Revenues	240	2,186	563	3,551
Operating segments | Coal Royalties
Reportable segment results
Revenues			10
Segment Adjusted EBITDA Expense	5,589	6,851	18,485	17,836
Segment Adjusted EBITDA	11,058	9,912	33,457	31,007
Total assets	313,044	319,930	313,044	319,930
Capital expenditures				400
Operating segments | Coal Royalties | Other revenues
Reportable segment results
Revenues			10
Other, Corporate and Elimination
Reportable segment results
Revenues	2,159	(3,986)	(700)	(5,556)
Segment Adjusted EBITDA Expense	(1,006)	(5,524)	(5,498)	(13,618)
Segment Adjusted EBITDA	342	(881)	(14)	2,560
Total assets	348,959	384,011	348,959	384,011
Capital expenditures	9,315	20,202	13,253	21,553
Other, Corporate and Elimination | Other revenues
Reportable segment results
Revenues	18,806	12,777	51,233	43,287
Elimination
Reportable segment results
Revenues	(16,647)	(16,763)	(51,933)	(48,843)
Elimination | Coal Royalties
Reportable segment results
Revenues	$ 16,647	$ 16,763	$ 51,933	$ 48,843

SEGMENT INFORMATION - EBITDA Ex

SEGMENT INFORMATION - EBITDA Expense Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Reconciliation of consolidated Segment Adjusted EBITDA Expense
Litigation expense accrual			$ (15,250)
Outside coal purchases	$ 8,192	$ 11,530	27,912	$ 15,739
Other expense (income)	681	(223)	2,245	173
Segment Adjusted EBITDA Expense	393,717	350,406	1,115,215	1,028,136
Product
Reconciliation of consolidated Segment Adjusted EBITDA Expense
Operating expenses (excluding depreciation, depletion and amortization)	$ 384,844	$ 339,099	$ 1,100,308	$ 1,012,224

SEGMENT INFORMATION - EBITDA Re

SEGMENT INFORMATION - EBITDA Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
Reconciliation of consolidated Segment Adjusted EBITDA to net income
Net income	$ 86,916	$ 101,509	$ 159,567	$ 155,351	$ 171,305	$ 192,678	$ 347,992	$ 519,334
Noncontrolling interest	(635)			(1,652)			(3,467)	(4,660)
NET INCOME ATTRIBUTABLE TO ARLP	86,281			153,699			344,525	514,674
General and administrative	21,878			20,097			64,569	61,312
Depreciation, depletion and amortization	72,971			65,393			204,974	199,582
Interest expense, net	7,352			5,067			21,018	21,761
Change in fair value of digital assets	(332)						(8,437)
Litigation expense accrual							15,250
Income tax expense	4,123			3,401			12,932	11,641
Consolidated Segment Adjusted EBITDA	192,273			247,657			654,831	808,970
JC Resources acquisition						$ (72,250)
Oil and gas acquisitions total	$ 10,500			$ 10,000			$ 15,200	13,900
JC Resources
Reconciliation of consolidated Segment Adjusted EBITDA to net income
JC Resources acquisition								$ 72,300