Arch Resources (ARCH) 10-Q 25 Apr 24 2024 Q1 Quarterly report Financial data

Cover Page

Cover Page - shares	3 Months Ended
	Mar. 31, 2024	Apr. 23, 2024
Cover page.
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
Document Transition Report	false
Entity File Number	1-13105
Entity Registrant Name	Arch Resources, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	43-0921172
Entity Address, Address Line One	One CityPlace Drive
Entity Address, Address Line Two	Suite 300
Entity Address, City or Town	St. Louis
Entity Address, State or Province	MO
Entity Address, Postal Zip Code	63141
City Area Code	314
Local Phone Number	994-2700
Title of 12(b) Security	Common stock, $.01 par value
Trading Symbol	ARCH
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business Company	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		18,116,434
Entity Central Index Key	0001037676
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Amendment Flag	false

Condensed Consolidated Income S

Condensed Consolidated Income Statements - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Condensed Consolidated Income Statements
Revenues	$ 680,190	$ 869,931
Costs, expenses and other operating
Cost of sales (exclusive of items shown separately below)	567,723	571,737
Depreciation, depletion and amortization	38,820	35,479
Accretion on asset retirement obligations	5,869	5,292
Selling, general and administrative expenses	25,587	26,022
Other operating income, net	(15,983)	(5,169)
Costs, expenses and other operating	622,016	633,361
Income from operations	58,174	236,570
Interest expense, net
Interest expense	(4,316)	(4,126)
Interest and investment income	6,100	3,336
Interest expense, net	1,784	(790)
Income before nonoperating expenses	59,958	235,780
Nonoperating expense
Non-service related pension and postretirement benefit (costs) credits	(286)	592
Net loss resulting from early retirement of debt		(1,126)
Nonoperating expenses	(286)	(534)
Income before income taxes	59,672	235,246
Provision for income taxes	3,719	37,138
Net income	$ 55,953	$ 198,108
Net income per common share
Basic earnings per share (in dollars per share)	$ 3.05	$ 11.05
Diluted earnings per share (in dollars per share)	$ 2.98	$ 10.02
Weighted average shares outstanding
Basic weighted average shares outstanding (in shares)	18,347	17,924
Diluted weighted average shares outstanding (in shares)	18,775	19,784
Dividends declared per common share (in dollars per share)	$ 1.65	$ 3.11

Condensed Consolidated Statemen

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Condensed Consolidated Statements of Comprehensive Income
Net Income (Loss)	$ 55,953	$ 198,108
Pension, postretirement and other post-employment benefits
Comprehensive loss before tax	(2,006)	(2,895)
Provision for income taxes	427	636
Other comprehensive loss, pension, postretirement and other post-employment benefits, net of tax	(1,579)	(2,259)
Available-for-sale securities
Comprehensive loss before tax	(4)	(15)
Provision for income taxes	1	3
Other comprehensive (loss) income, available-for-sale securities, net of tax	(3)	(12)
Total other comprehensive loss	(1,582)	(2,271)
Total comprehensive income	$ 54,371	$ 195,837

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Current assets
Cash and cash equivalents	$ 285,531	$ 287,807
Short-term investments	34,252	32,724
Restricted cash	1,100	1,100
Trade accounts receivable (net of $0 allowance at March 31, 2024 and December 31, 2023)	224,084	273,522
Other receivables	10,519	13,700
Inventories	243,690	244,261
Other current assets	63,393	64,653
Total current assets	862,569	917,767
Property, plant and equipment, net	1,235,775	1,228,891
Other assets
Deferred income taxes	120,792	124,024
Equity investments	24,053	22,815
Fund for asset retirement obligations	144,146	142,266
Other noncurrent assets	47,351	48,410
Total other assets	336,342	337,515
Total assets	2,434,686	2,484,173
Current Liabilities
Accounts payable	178,119	205,001
Accrued expenses and other current liabilities	113,360	127,617
Current maturities of debt	35,341	35,343
Total current liabilities	326,820	367,961
Long-term debt	107,959	105,252
Asset retirement obligations	260,252	255,740
Accrued pension benefits	861	878
Accrued postretirement benefits other than pension	47,384	47,494
Accrued workers' compensation	155,838	154,650
Other noncurrent liabilities	68,124	72,742
Total liabilities	967,238	1,004,717
Stockholders' equity
Common stock, $0.01 par value, authorized 300,000 shares, issued 30,785 and 30,557 shares at March 31, 2024 and December 31, 2023, respectively	308	306
Paid-in capital	754,054	720,029
Retained earnings	1,854,621	1,830,018
Treasury stock, 12,607 and 12,197 shares at March 31, 2024 and December 31, 2023, respectively, at cost	(1,178,735)	(1,109,679)
Accumulated other comprehensive income	37,200	38,782
Total stockholders' equity	1,467,448	1,479,456
Total liabilities and stockholders' equity	$ 2,434,686	$ 2,484,173

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Condensed Consolidated Balance Sheets
Trade accounts receivable, allowance	$ 0	$ 0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	300,000	300,000
Common stock, shares issued (in shares)	30,785	30,557
Treasury stock, shares (in shares)	12,607	12,197

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Operating activities
Net income	$ 55,953	$ 198,108
Adjustments to reconcile to cash from operating activities:
Depreciation, depletion and amortization	38,820	35,479
Accretion on asset retirement obligations	5,869	5,292
Deferred income taxes	3,660	35,548
Employee stock-based compensation expense	5,588	6,767
Amortization relating to financing activities	658	450
Gain on disposals and divestitures, net	(24)	(279)
Reclamation work completed	(1,355)	(3,887)
Contribution to fund for asset retirement obligations	(1,881)	(1,141)
Changes in:
Receivables	52,618	(57,968)
Inventories	571	(48,140)
Accounts payable, accrued expenses and other current liabilities	(33,481)	(63,508)
Income taxes, net	30	1,491
Other	1,240	17,909
Cash provided by operating activities	128,266	126,121
Investing activities
Capital expenditures	(45,446)	(30,541)
Minimum royalty payments	(50)	(113)
Proceeds from disposals and divestitures	90	343
Purchases of short-term investments	(11,332)	(2,930)
Proceeds from sales of short-term investments	9,867	8,000
Investments in and advances to affiliates, net	(4,203)	(4,329)
Cash used in investing activities	(51,074)	(29,570)
Financing activities
Proceeds from issuance of term loan due 2025	20,000
Payments on term loan due 2024	(3,502)	(750)
Payments on convertible debt		(58,430)
Net payments on other debt	(12,796)	(12,647)
Debt financing costs	(1,500)
Purchases of treasury stock	(13,749)	(20,806)
Dividends paid	(43,662)	(66,902)
Payments for taxes related to net share settlement of equity awards	(24,259)	(27,055)
Proceeds from warrants exercised		43,719
Cash used in financing activities	(79,468)	(142,871)
Decrease in cash and cash equivalents, including restricted cash	(2,276)	(46,320)
Cash and cash equivalents, including restricted cash, beginning of period	288,907	237,159
Cash and cash equivalents, including restricted cash, end of period	286,631	190,839
SUPPLEMENTAL CASH FLOW INFORMATION
Cash and cash equivalents	285,531	189,739
Restricted Cash	$ 1,100	$ 1,100

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock	Paid-in Capital	Treasury Stock, at cost	Retained Earnings	Accumulated Other Comprehensive Income	Total
Beginning Balance at Dec. 31, 2022	$ 288	$ 724,660	$ (986,171)	$ 1,565,374	$ 61,429	$ 1,365,580
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends on common shares				(55,140)		(55,140)
Dividend Equivalents earned on RSU grants		120		(2,354)		(2,234)
Purchase of common stock under share repurchase program		(13)	(18,994)			(19,007)
Employee stock-based compensation		6,767				6,767
Cash paid for convertible debt repurchased		(44,486)				(44,486)
Issuance of shares of common stock under long-term incentive plan	3					3
Common stock withheld related to net share settlement of equity awards		(27,055)				(27,055)
Issuance of shares of common stock for warrants exercised	10	43,719				43,729
Total comprehensive income (loss)				198,108	(2,271)	195,837
Ending Balance at Mar. 31, 2023	301	703,712	(1,005,165)	1,705,988	59,158	1,463,994
Beginning Balance at Dec. 31, 2023	306	720,029	(1,109,679)	1,830,018	38,782	1,479,456
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends on common shares				(30,671)		(30,671)
Dividend Equivalents earned on RSU grants		72		(679)		(607)
Purchase of common stock under share repurchase program			(16,432)			(16,432)
Employee stock-based compensation		5,588				5,588
Receipt of shares from exercise of capped call, value		52,624	(52,624)
Common stock withheld related to net share settlement of equity awards		(24,259)				(24,259)
Issuance of shares of common stock for warrants exercised	2					2
Total comprehensive income (loss)				55,953	(1,582)	54,371
Ending Balance at Mar. 31, 2024	$ 308	$ 754,054	$ (1,178,735)	$ 1,854,621	$ 37,200	$ 1,467,448

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Stockholders' Equity (Parenthetical) - shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Condensed Consolidated Statements of Stockholders' Equity
Purchase of shares of common stock under share repurchase program	94,701	131,156
Issuance of shares of common stock under long-term incentive plan		275,053
Issuance of shares of common stock for warrants exercised	227,981	1,037,679
Receipt of shares from the exercise of capped call	315,721

Basis of Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2024
Basis of Presentation
Basis of Presentation	1. The accompanying unaudited condensed consolidated financial statements include the accounts of Arch Resources, Inc. (“Arch Resources”) and its subsidiaries and controlled entities (“Arch” or the “Company”). Unless the context indicates otherwise, the terms “Arch” and the “Company” are used interchangeably in this Quarterly Report on Form 10-Q. The Company’s primary business is the production of metallurgical and thermal coal from underground and surface mines located throughout the United States, for sale to steel producers, utility companies, and industrial accounts both in the United States and around the world. The Company currently operates mining complexes in West Virginia, Wyoming and Colorado. All subsidiaries are wholly owned. Intercompany transactions and accounts have been eliminated in consolidation. The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States for interim financial reporting and U.S. Securities and Exchange Commission regulations. In the opinion of management, all adjustments, consisting of normal, recurring accruals considered necessary for a fair presentation, have been included. Results of operations for the three months ended March 31, 2024 are not necessarily indicative of results to be expected for the year ending December 31, 2024. These financial statements should be read in conjunction with the audited financial statements and related notes as of and for the year ended December 31, 2023 included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023 filed with the U.S. Securities and Exchange Commission. Certain amounts have been reclassified to conform to the current period's presentation.

Accounting Policies

Accounting Policies	3 Months Ended
	Mar. 31, 2024
Accounting Policies
Accounting Policies	2. Recently Adopted Accounting Guidance There is no recently issued accounting guidance effective that is expected to have a material impact on the Company’s financial position, results of operations, or liquidity. ​ Recent Accounting Guidance Issued Not Yet Effective ​ In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which includes amendments that further enhance income tax disclosures, primarily through standardization and disaggregation of rate reconciliation categories and income taxes paid by jurisdiction. The amendments are effective for the Company’s annual periods beginning June 1, 2025, with early adoption permitted, and should be applied either prospectively or retrospectively. The Company is currently evaluating the ASU to determine its impact on the Company’s disclosures. ​

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	3 Months Ended
	Mar. 31, 2024
Accumulated Other Comprehensive Income (Loss).
Accumulated Other Comprehensive Income (Loss)	3. The following items are included in accumulated other comprehensive income (loss) (“AOCI”), net of tax: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pension, ​ ​ ​ ​ ​ ​ Postretirement ​ ​ ​ ​ Accumulated ​ ​ and Other Post- ​ ​ ​ ​ Other ​ ​ Employment ​ Available-for- ​ Comprehensive ​ ​ Benefits ​ Sale Securities ​ Income (loss) ​ ​ ​ ​ ​ ​ ​ ​ ​ Balances at December 31, 2023 ​ $ 38,783 ​ $ (1) $ 38,782 Unrealized gains ​ — ​ 5 5 Amounts reclassified from accumulated other comprehensive income ​ (2,006) ​ (9) (2,015) Tax effect ​ ​ 427 ​ ​ 1 ​ ​ 428 Balances at March 31, 2024 ​ $ 37,204 ​ $ (4) $ 37,200 ​ The following amounts were reclassified out of AOCI: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, Line Item in the Condensed Consolidated Details About AOCI Components 2024 2023 Income Statements ​ ​ (In thousands) ​ ​ Pension, postretirement and other post-employment benefits ​ ​ ​ ​ ​ ​ ​ ​ Amortization of actuarial gains, net 1 ​ $ 2,006 ​ $ 2,858 Non-service related pension and postretirement benefit credits Amortization of prior service credits ​ ​ — ​ ​ 37 ​ Non-service related pension and postretirement benefit credits ​ ​ (427) ​ (636) Provision for income taxes ​ ​ $ 1,579 ​ $ 2,259 Net of tax ​ ​ ​ ​ ​ ​ ​ ​ ​ Available-for-sale securities 2 ​ $ 9 ​ $ (22) Interest and investment income ​ ​ (1) ​ 5 Provision for income taxes ​ ​ $ 8 ​ $ (17) Net of tax 1 2

Inventories

Inventories	3 Months Ended
	Mar. 31, 2024
Inventories
Inventories	4. Inventories consist of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, December 31, ​ 2024 2023 ​ ​ (In thousands) Coal ​ $ 95,492 ​ $ 99,174 Repair parts and supplies ​ 148,198 ​ 145,087 ​ ​ $ 243,690 ​ $ 244,261 ​ The repair parts and supplies are stated net of an allowance for slow-moving and obsolete inventories of $1.6 million at March 31, 2024 and $1.6 million at December 31, 2023.

Investments in Available-for-Sa

Investments in Available-for-Sale Securities	3 Months Ended
	Mar. 31, 2024
Investments in Available-for-Sale Securities
Investments in Available-for-Sale Securities	5. The Company has invested in marketable debt securities, primarily highly liquid U.S. Treasury securities and investment grade corporate bonds. These investments are held in the custody of a major financial institution. These securities are classified as available-for-sale securities and, accordingly, the unrealized gains and losses are recorded through other comprehensive income. The Company’s investments in available-for-sale marketable securities are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2024 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross ​ ​ Allowance ​ ​ ​ ​ ​ ​ ​ ​ Unrealized ​ ​ for - Credit ​ Fair ​ Cost Basis Gains Losses ​ ​ Losses Value ​ ​ (In thousands) Available-for-sale: ​ ​ ​ ​ ​ ​ ​ U.S. government and agency securities ​ $ 31,291 ​ $ 12 ​ $ (7) ​ $ — ​ $ 31,296 Corporate notes and bonds ​ 2,956 ​ 4 ​ (4) ​ — ​ 2,956 Total Investments ​ $ 34,247 ​ $ 16 ​ $ (11) ​ $ — ​ $ 34,252 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2023 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross ​ ​ Allowance ​ ​ ​ ​ ​ ​ ​ ​ Unrealized ​ ​ for - Credit ​ Fair ​ Cost Basis Gains ​ Losses ​ ​ Losses Value ​ (In thousands) Available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. government and agency securities ​ $ 28,764 ​ $ 14 ​ $ (5) ​ $ — ​ $ 28,773 Corporate notes and bonds ​ 3,951 ​ 1 ​ (1) ​ — ​ 3,951 Total Investments ​ $ 32,715 ​ $ 15 ​ $ (6) ​ $ — ​ $ 32,724 ​ The aggregate fair value of investments with unrealized losses that had been owned for less than a year was $5.6 million and $2.2 million at March 31, 2024 and December 31, 2023, respectively. The aggregate fair value of investments with unrealized losses that were owned for over a year was million at March 31, 2024 and December 31, 2023, respectively. The unrealized losses in the Company’s portfolio at March 31, 2024 are the result of normal market fluctuations. The Company does not intend to sell these investments before recovery of their amortized cost base. The debt securities outstanding at March 31, 2024 have maturity dates ranging from the second quarter of 2024 through the second quarter of 2025. The Company classifies its investments as current based on the nature of the investments and their availability to provide cash for use in current operations, if needed.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	3 Months Ended
	Mar. 31, 2024
Accrued Expenses and Other Current Liabilities.
Accrued Expenses and Other Current Liabilities	6. Accrued expenses and other current liabilities consist of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, December 31, ​ ​ 2024 ​ 2023 ​ ​ (In thousands) Payroll and employee benefits ​ $ 30,832 ​ $ 37,259 Taxes other than income taxes ​ 44,063 ​ 51,155 Interest ​ 1,372 ​ 2,395 Workers’ compensation ​ 17,775 ​ 18,724 Asset retirement obligations ​ 6,091 ​ 6,089 Other ​ 13,227 ​ 11,995 ​ ​ $ 113,360 ​ $ 127,617 ​ ​

Debt and Financing Arrangements

Debt and Financing Arrangements	3 Months Ended
	Mar. 31, 2024
Debt and Financing Arrangements
Debt and Financing Arrangements	7. ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, December 31, ​ ​ 2024 ​ 2023 ​ (In thousands) Term loan due 2025 ($20.0 million face value) ​ $ 20,000 ​ $ — Term loan due 2024 ​ ​ — ​ ​ 3,502 Tax Exempt Bonds ($98.1 million face value) ​ ​ 98,075 ​ ​ 98,075 Other ​ 27,733 ​ 40,529 Debt issuance costs ​ (2,508) ​ (1,511) ​ ​ ​ 143,300 ​ ​ 140,595 Less: current maturities of debt ​ 35,341 ​ 35,343 Long-term debt ​ $ 107,959 ​ $ 105,252 ​ Term Loan Facility On February 8, 2024, the Company entered into a new senior secured term loan credit agreement in the principal amount of $20.0 million (the “Term Loan”) with PNC Bank, National Association, as administrative and collateral agent. The Term Loan requires quarterly principal amortization payments of $3.3 million and matures on June 30, 2025. The interest rate on the facility is, at the option of Arch Resources, either (i) Secured Overnight Financing Rate (“SOFR”) plus a SOFR adjustment of .10% plus an applicable margin of 3.00%, subject to a SOFR floor of 0.00%, or (ii) a base rate plus an applicable margin of 2.00%. ​ The Term Loan is guaranteed by substantially all of the domestic subsidiaries of the Company. Additionally, the Term Loan is secured by substantially all the assets of the Company and the guarantors, subject to customary exceptions (including an exclusion for owned and leased real property). ​ The Term Loan contains the following financial maintenance covenants: (i) total net leverage not to exceed 2.00 to 1.00 for the trailing four four ​ The Term Loan is subject to certain usual and customary mandatory prepayment events, including 100% of net cash proceeds of debt issuances (other than debt permitted to be incurred under the terms of the Term Loan). ​ The Term Loan contains customary affirmative and negative covenants and representations; and customary events of default, subject to customary thresholds and exceptions. As of March 31, 2024, the Company was in compliance with the Term Loan debt covenants. ​ The proceeds from the Term Loan were used to pay off the $3.5 million balance of the existing term loan debt facility. Additionally, the Company incurred approximately $1.5 million in debt issuance costs related to the Term Loan. ​ Accounts Receivable Securitization Facility On August 3, 2022, the Company amended and extended its existing trade accounts receivable securitization facility provided to Arch Receivable Company, LLC, a special-purpose entity that is a wholly owned subsidiary of Arch Resources (“Arch Receivable”) (the “Securitization Facility”), which supports the issuance of letters of credit and requests for cash advances. The amendment to the Securitization Facility increased the size of the facility from $110 million to $150 million of borrowing capacity and extended the maturity date to August 1, 2025. Under the Securitization Facility, Arch Receivable, Arch Resources and certain of Arch Resources’ subsidiaries party to the Securitization Facility have granted to the administrator of the Securitization Facility a first priority security interest in eligible trade accounts receivable generated by such parties from the sale of coal and all proceeds thereof. As of March 31, 2024, letters of credit totaling Inventory-Based Revolving Credit Facility On August 3, 2022, Arch Resources amended the senior secured inventory-based revolving credit facility in an aggregate principal amount of $50 million (the “Inventory Facility”). Availability under the Inventory Facility is subject to a borrowing base consisting of (i) 85% of the net orderly liquidation value of eligible coal inventory, plus (ii) the lesser of (x) 85% of the net orderly liquidation value of eligible parts and supplies inventory and (y) 35% of the amount determined pursuant to clause (i), plus (iii) 100% of Arch Resources’ Eligible Cash (defined in the Inventory Facility), subject to reduction for reserves imposed by Regions. The amendment of the Inventory Facility extended the maturity of the facility to August 3, 2025; maintained the minimum liquidity requirement of $100 million and included provisions that reduce the advance rates for coal inventory and parts and supplies, depending on liquidity, as defined in the agreement. The Inventory Facility contains certain customary affirmative and negative covenants; events of default, subject to customary thresholds and exceptions; and representations, including certain cash management and reporting requirements that are customary for asset-based credit facilities. The Inventory Facility also includes a requirement to maintain liquidity equal to or exceeding $100 million at all times. As of March 31, 2024, letters of credit totaling $26.2 million were outstanding under the facility with $23.8 million available for borrowings. Equipment Financing On July 29, 2021, the Company entered into an equipment financing arrangement accounted for as debt. The Company received maturing on February 1, 2025. Upon maturity, the Company will have the option to purchase the equipment. Tax Exempt Bonds On July 2, 2020, the West Virginia Economic Development Authority (the “Issuer”) issued $53.1 million aggregate principal amount of Solid Waste Disposal Facility Revenue Bonds (Arch Resources Project), Series 2020 (the “Tax Exempt Bonds”) pursuant to an Indenture of Trust dated as of June 1, 2020 (the “Indenture of Trust”) between the Issuer and Citibank, N.A., as trustee (the “Trustee”). On March 4, 2021, the Issuer issued an additional million of Series 2021 Tax Exempt Bonds. The proceeds of the Tax Exempt Bonds were loaned to the Company pursuant to a Loan Agreement dated as of June 1, as supplemented by a First Amendment to Loan Agreement dated as of March 1, 2021 (collectively, the “Loan Agreement”), each between the Issuer and the Company. The Tax Exempt Bonds are payable solely from payments to be made by the Company under the Loan Agreement as evidenced by a Note from the Company to the Trustee. The proceeds of the Tax Exempt Bonds have been used to finance certain costs of the acquisition, construction, reconstruction, and equipping of solid waste disposal facilities at the Company’s Leer South development, and for capitalized interest and certain costs related to issuance of the Tax Exempt Bonds. The Tax Exempt Bonds bear interest payable each January 1 and July 1, commencing January 1, 2021 for the Series 2020 and July 1, 2021 for the Series 2021, and have a final maturity of July 1, 2045; however, the Tax Exempt Bonds are subject to mandatory tender on July 1, 2025 at a purchase price equal to 100% of the principal amount of the Tax Exempt Bonds, plus accrued interest to July 1, 2025. The Series 2020 and Series 2021 Tax Exempt Bonds bear interest of Convertible Debt On November 3, 2020, the Company issued $155.3 million in aggregate principal amount of 5.25% convertible senior notes due 2025 (“Convertible Notes ” or “Convertible Debt”). The net proceeds from the issuance of the Convertible Notes, after deducting offering related costs of $5.1 million and cost of a “Capped Call Transaction” as defined below of $17.5 million, were approximately $132.7 million. ​ For the three months ended March 31, 2023, the Company repurchased the remaining Convertible Notes with a principal amount of $13.2 million for aggregate consideration consisting of $58.4 million in cash. In connection with the repurchase, the Company recognized a loss of $1.1 million. This amount is included as “Net loss resulting from early retirement of debt” in the accompanying Condensed Consolidated Income Statements. ​ Capped Call Transactions ​ On February 16, 2024, Arch Resources, Inc. (the “Company”) agreed with each of Bank of Montreal, Goldman Sachs & Co. LLC and Jefferies International Limited (each a “Counterparty” and collectively, the “Counterparties”) to terminate and unwind certain capped call transactions by and between the Company and each Counterparty (such transactions, the “Capped Calls”). The Company entered into the Capped Calls in connection with the offering of its now-retired Convertible Notes, in order to reduce the potential dilution upon conversion of the notes. The Company retired

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2024
Income Taxes
Income Taxes	8. The Company's effective tax rate for three months ended March 31, 2024 is based on its estimated full year effective tax rate, adjusted for discrete items. The effective tax rate for the three months ended March 31, 2024 was ​ For the three months ended March 31, 2023, the Company's effective tax rate was 15.8%. The effective tax rate for the three months ended March 31, 2023 differed from the U.S. federal statutory rate of 21%, primarily due to the income tax benefit for excess percentage depletion and discrete tax benefits related to equity compensation. ​ ​

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2024
Fair Value Measurements
Fair Value Measurements	9. The hierarchy of fair value measurements assigns a level to fair value measurements based on the inputs used in the respective valuation techniques. The levels of the hierarchy, as defined below, give the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities and the lowest priority to unobservable inputs. ● Level 1 is defined as observable inputs such as quoted prices in active markets for identical assets. Level 1 assets include U.S. Treasury securities, and coal swaps and futures that are submitted for clearing on the New York Mercantile Exchange. ● Level 2 is defined as observable inputs other than Level 1 prices. These include quoted prices for similar assets or liabilities in an active market, quoted prices for identical assets and liabilities in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. The Company’s Level 2 assets and liabilities include U.S. government agency securities, coal commodity contracts, and interest rate swaps with fair values derived from quoted prices in over-the-counter markets or from prices received from direct broker quotes. ● Level 3 is defined as unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions. These include the Company’s commodity option contracts (heating oil) valued using modeling techniques, such as Black-Scholes, that require the use of inputs, particularly volatility, that are rarely observable. The table below sets forth, by level, the Company’s financial assets and liabilities that are recorded at fair value in the accompanying Condensed Consolidated Balance Sheet: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2024 ​ Total Level 1 Level 2 Level 3 ​ ​ (In thousands) Assets: ​ ​ ​ ​ Investments in marketable securities ​ $ 34,252 ​ $ 31,296 ​ $ 2,956 ​ $ — Fund for asset retirement obligations ​ ​ 144,146 ​ ​ 144,146 ​ ​ — ​ ​ — Total assets ​ $ 178,398 ​ $ 175,442 ​ $ 2,956 ​ $ — ​ The Company’s contracts with its counterparties allow for the settlement of contracts in an asset position with contracts in a liability position in the event of default or termination. For classification purposes, the Company records the net fair value of all the positions with these counterparties as a net asset or liability. Each level in the table above displays the underlying contracts according to their classification in the accompanying Condensed Consolidated Balance Sheet, based on this counterparty netting. Fair Value of Long-Term Debt At March 31, 2024 and December 31, 2023, the fair value of the Company’s debt, including amounts classified as current, was $145.8 million and $142.1 million, respectively. Fair values are based upon observed prices in an active market, when available, or from valuation models using market information, which fall into Level 2 in the fair value hierarchy.

Earnings per Common Share

Earnings per Common Share	3 Months Ended
	Mar. 31, 2024
Earnings per Common Share
Earnings per Common Share	10. The Company computes basic net income per share using the weighted average number of common shares outstanding during the period. Diluted net income per share is computed using the weighted average number of common shares and the effect of potentially dilutive securities outstanding during the period. Potentially dilutive securities may consist of warrants, restricted stock units, and convertible debt. The dilutive effect of outstanding warrants and restricted stock units is reflected in diluted earnings per share by application of the treasury stock method whereas the Convertible Debt uses the if converted method. The following table provides the basic and diluted earnings per share by reconciling the numerators and denominators of the computations: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ ​ 2024 ​ 2023 (In Thousands) ​ ​ ​ Net income attributable to common shares $ 55,953 $ 198,108 Adjustment of interest expense attributable to Convertible Notes ​ ​ — ​ ​ 108 Diluted net income attributable to common stockholders ​ ​ 55,953 ​ ​ 198,216 ​ ​ ​ ​ ​ ​ ​ Basic weighted average shares outstanding ​ ​ 18,347 ​ ​ 17,924 Effect of dilutive securities ​ ​ 428 ​ ​ 1,524 Convertible Notes (a) ​ ​ — ​ ​ 336 Diluted weighted average shares outstanding ​ 18,775 ​ 19,784 (a) Diluted weighted average common shares outstanding includes the dilutive effect had the Company's Convertible Notes been converted at the beginning of the year ended December 31, 2023. If converted by the holder, the Company may settle in cash, shares of the Company's common stock or a combination thereof, at the Company's election. The Capped Call Transaction is anti-dilutive and is excluded from the calculation of diluted earnings per share. ​

Workers Compensation Expense

Workers Compensation Expense	3 Months Ended
	Mar. 31, 2024
Workers Compensation Expense
Workers' Compensation Expense	11. The Company is liable under the Federal Mine Safety and Health Act of 1969, as subsequently amended, to provide for pneumoconiosis (occupational disease) benefits to eligible employees, former employees and dependents. The Company currently provides for federal claims principally through a self-insurance program. The Company is also liable under various state workers’ compensation statutes for occupational disease benefits. The occupational disease benefit obligation represents the present value of the actuarially computed present and future liabilities for such benefits over the employees’ applicable years of service. In October 2019, the Company filed an application with the Office of Workers’ Compensation Programs (“OWCP”) within the Department of Labor for reauthorization to self-insure federal black lung benefits. In February 2020, the Company received a reply from the OWCP confirming its status to remain self-insured contingent upon posting additional collateral of of receipt of the letter. The Company is currently appealing the ruling from the OWCP and has received an extension to self-insure during the appeal process. On January 18, 2023, the OWCP proposed revisions to regulations under the Black Lung Benefits Act governing authorization of self-insurers. The revisions seek to codify the practice of basing a self-insured operator’s security requirement on an actuarial assessment of its total present and future black lung liability. A material change to the regulations is the requirement that all self-insured operators must post security equal to The proposed regulations were posted to the Federal Register on January 19, 2023 with written comments to be accepted within 60 days of this date. A subsequent extended comment period expired on April 19, 2023; however, the final regulations have not yet been published. ​ If the above regulation is codified into law, the Company will be required to post additional collateral to maintain its self-insured status. The Company is evaluating alternatives to self-insurance, including the purchase of commercial insurance to cover these claims. Additionally, the Company is assessing additional sources of liquidity, and other items to satisfy the proposed regulations. ​ In addition, the Company is liable for workers’ compensation benefits for traumatic injuries which are calculated using actuarially-based loss rates, loss development factors and discounted based on a risk free rate. Traumatic workers’ compensation claims are insured with varying retentions/deductibles, or through state-sponsored workers’ compensation programs. Workers’ compensation expense consists of the following components: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ ​ 2024 2023 ​ ​ (In thousands) ​ Self-insured occupational disease benefits: ​ ​ Service cost ​ $ 1,278 ​ $ 993 ​ Interest cost (1) ​ 1,565 ​ 1,511 ​ Net amortization (1) ​ (3) ​ (241) ​ Total occupational disease ​ $ 2,840 ​ $ 2,263 ​ Traumatic injury claims and assessments ​ 2,484 ​ 1,690 ​ Total workers’ compensation expense ​ $ 5,324 ​ $ 3,953 ​ (1) In accordance with the adoption of ASU 2017-07, “Compensation-Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost,” these costs are recorded within Nonoperating expenses in the Condensed Consolidated Income Statements on the line item “Non-service related pension and postretirement benefit (credits) costs.”

Employee Benefit Plans

Employee Benefit Plans	3 Months Ended
	Mar. 31, 2024
Employee Benefit Plans
Employee Benefit Plans	12. Employee Benefit Plans The following table details the components of pension benefit credit: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ ​ 2024 2023 ​ ​ (In thousands) Interest cost (1) ​ $ 11 ​ $ 1,534 ​ Expected return on plan assets (1) ​ — ​ ​ (1,518) ​ Amortization of prior service credits (1) ​ — ​ (37) ​ Amortization of other actuarial (gains) (1) ​ (22) ​ (195) ​ Net benefit credit ​ $ (11) ​ $ (216) ​ ​ ​ The following table details the components of other postretirement benefit credit: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ ​ 2024 2023 ​ ​ (In thousands) Service cost ​ $ 49 ​ $ 58 ​ Interest cost (1) ​ 605 ​ 674 ​ Amortization of other actuarial gains (1) ​ (1,981) ​ (2,422) ​ Net benefit credit ​ $ (1,327) ​ $ (1,690) ​ (1) In accordance with the adoption of ASU 2017-07, “Compensation-Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost,” these costs are recorded within Nonoperating expenses in the Condensed Consolidated Income Statements on the line item “Non-service related pension and postretirement benefit credits (costs).” ​ In February 2022, the Board of Directors approved the termination of the Company’s Cash Balance Pension Plan. The Company has executed plan amendments regarding the termination and filed an Application for Determination for Terminating Pension Plan with the Internal Revenue Service (“IRS”), which was approved by the IRS during the first quarter of 2023. The Company also prepared and filed appropriate notices and documents related to the Pension Plan's termination and wind-down with the Pension Benefit Guaranty Corporation (“PBGC”). The Company no longer administers or pays the retirement benefits of the Cash Balance Pension Plan.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2024
Commitments and Contingencies
Commitments and Contingencies	13. Commitments and Contingencies The Company accrues for costs related to contingencies when a loss is probable and the amount is reasonably determinable. Disclosure of contingencies is included in the financial statements when it is at least reasonably possible that a material loss or an additional material loss in excess of amounts already accrued may be incurred. The Company is a party to numerous claims and lawsuits with respect to various matters. The ultimate resolution of any such legal matter could result in outcomes that may be materially different from amounts the Company has accrued for such matters. The Company believes it has recorded adequate reserves for these matters. In the normal course of business, the Company is a party to certain financial instruments with off-balance sheet risk, such as bank letters of credit, performance or surety bonds, and other guarantees and indemnities related to the obligations of affiliated entities which are not reflected in the Company’s Condensed Consolidated Balance Sheets. However, the underlying liabilities that they secure, such as asset retirement obligations, workers’ compensation liabilities, and other obligations, are reflected in the Company’s Condensed Consolidated Balance Sheets. As of March 31, 2024, the Company had outstanding surety bonds with a face amount of $500.1 million to secure various obligations and commitments and $78.1 million of letters of credit under its Securitization and Inventory Facilities used to collateralize certain obligations. The Company posted million in cash collateral related to various obligations; this amount is recorded within “Other noncurrent assets” on the Condensed Consolidated Balance Sheets. As of March 31, 2024, the Company’s reclamation-related obligations of $266.3 million were supported by surety bonds of $403.2 million. The Company has posted million in cash collateral related to reclamation surety bonds. Additionally, in the first quarter of 2024, the Company contributed an additional million as of March 31, 2024. This amount is recorded as “Fund for asset retirement obligations” on the Condensed Consolidated Balance Sheets.

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 2024
Segment Information
Segment Information	14. The Company’s reportable business segments are based on two distinct lines of business, metallurgical and thermal, and may include a number of mine complexes. The Company manages its coal sales by market and coal quality, not by individual mining complex. Geology, coal transportation routes to customers, and regulatory environments also have a significant impact on the Company’s marketing and operations management. Mining operations are evaluated based on Adjusted EBITDA, per-ton cash operating costs (defined as including all mining costs except depreciation, depletion, amortization, accretion on asset retirement obligations, and pass-through transportation expenses, divided by segment tons sold), and on other non-financial measures, such as safety and environmental performance. Adjusted EBITDA is not a measure of financial performance in accordance with generally accepted accounting principles, and items excluded from Adjusted EBITDA are significant in understanding and assessing the Company’s financial condition. Therefore, Adjusted EBITDA should not be considered in isolation, nor as an alternative to net income, income from operations, cash flows from operations or as a measure of our profitability, liquidity or performance under generally accepted accounting principles. The Company uses Adjusted EBITDA to measure the operating performance of its segments and allocate resources to the segments. Furthermore, analogous measures are used by industry analysts and investors to evaluate the Company’s operating performance. Investors should be aware that the Company’s presentation of Adjusted EBITDA may not be comparable to similarly titled measures used by other companies. The Company reports its results of operations primarily through the following reportable segments: Metallurgical (MET) segment, containing the Company’s metallurgical operations in West Virginia, and the Thermal segment containing the Company’s thermal operations in Wyoming and Colorado. Reporting segment results for the three months ended March 31, 2024 and 2023 are presented below. The Corporate, Other, and Eliminations grouping includes these charges: idle operations; equity investments; change in fair value of coal derivatives, net; corporate overhead; land management activities; certain miscellaneous revenue; and the elimination of intercompany transactions. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other and ​ ​ ​ (In thousands) ​ MET ​ Thermal ​ Eliminations ​ Consolidated ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2024 ​ ​ ​ ​ ​ ​ ​ ​ Revenues ​ $ 417,065 ​ $ 263,125 ​ $ — $ 680,190 Adjusted EBITDA ​ 129,536 ​ 930 ​ (27,603) 102,863 Depreciation, depletion and amortization ​ 31,390 ​ 7,168 ​ 262 38,820 Accretion on asset retirement obligation ​ 647 ​ 4,810 ​ 412 5,869 Capital expenditures ​ 37,033 ​ 7,544 ​ 869 45,446 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2023 ​ ​ ​ ​ ​ ​ ​ Revenues ​ $ 536,172 ​ $ 333,759 ​ $ — ​ $ 869,931 Adjusted EBITDA ​ 263,057 ​ 46,255 ​ (31,971) ​ 277,341 Depreciation, depletion and amortization ​ 27,853 ​ 7,408 ​ 218 ​ 35,479 Accretion on asset retirement obligation ​ 615 ​ 4,314 ​ 363 ​ 5,292 Capital expenditures ​ 24,761 ​ 5,493 ​ 287 ​ 30,541 ​ A reconciliation of net income to Adjusted EBITDA and segment Adjusted EBITDA from coal operations follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, (In thousands) 2024 2023 Net income ​ $ 55,953 ​ $ 198,108 Provision for income taxes ​ ​ 3,719 ​ ​ 37,138 Interest expense, net ​ (1,784) ​ 790 Depreciation, depletion and amortization ​ 38,820 ​ 35,479 Accretion on asset retirement obligations ​ 5,869 ​ 5,292 Non-service related pension and postretirement benefit costs (credits) ​ ​ 286 ​ ​ (592) Net loss resulting from early retirement of debt ​ — ​ 1,126 Adjusted EBITDA ​ $ 102,863 ​ $ 277,341 EBITDA from idled or otherwise disposed operations ​ ​ 3,697 ​ ​ 4,032 Selling, general and administrative expenses ​ ​ 25,587 ​ ​ 26,022 Other ​ ​ (1,681) ​ ​ 1,917 Segment Adjusted EBITDA from coal operations ​ $ 130,466 ​ $ 309,312 ​

Revenue Recognition

Revenue Recognition	3 Months Ended
	Mar. 31, 2024
Revenue Recognition
Revenue Recognition	15. ASC 606-10-50-5 requires that entities disclose disaggregated revenue information in categories (such as type of goods or services, geography, market, type of contract, etc.) that depict how the nature, amount, timing, and uncertainty of revenue and cash flow are affected by economic factors. ASC 606-10-55-89 explains that the extent to which an entity’s revenue is disaggregated depends on the facts and circumstances that pertain to the entity’s contracts with customers and that some entities may need to use more than one type of category to meet the objective for disaggregating revenue. In general, the Company’s business segmentation is aligned according to the nature and economic characteristics of its coal and customer relationships and provides meaningful disaggregation of each segment’s results. The Company has further disaggregated revenue between North America and Seaborne revenues which depicts the pricing and contract differences between the two. North America revenue is characterized by contracts with a term of one year or longer and typically the pricing is fixed; whereas Seaborne revenue generally is derived from spot or short term contracts with an index-based pricing mechanism. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other and ​ ​ ​ ​ ​ MET ​ Thermal ​ Eliminations ​ Consolidated ​ (in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2024 ​ ​ ​ ​ ​ ​ ​ ​ North America revenues ​ $ 35,584 ​ $ 205,663 ​ $ — ​ $ 241,247 Seaborne revenues ​ 381,481 ​ 57,462 ​ — ​ 438,943 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total revenues ​ $ 417,065 ​ $ 263,125 ​ $ — ​ $ 680,190 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2023 ​ ​ ​ ​ ​ ​ ​ ​ North America revenues ​ $ 71,407 ​ $ 287,259 ​ $ — ​ $ 358,666 Seaborne revenues ​ 464,765 ​ 46,500 ​ — ​ 511,265 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total revenues ​ $ 536,172 ​ $ 333,759 ​ $ — ​ $ 869,931 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of March 31, 2024, the Company has outstanding performance obligations for the remainder of 2024 of 40.9 million tons of fixed price contracts and 5.2 million tons of variable price contracts. Additionally, the Company has outstanding performance obligations beyond 2024 of approximately 66.5 million tons of fixed price contracts and 1.7 million tons of variable price contracts. ​

Leases

Leases	3 Months Ended
	Mar. 31, 2024
Leases
Leases	16. The Company has operating and financing leases for mining equipment, office equipment, office space and transloading terminals with remaining lease terms ranging from less than one year to approximately three years. Some of these leases include both lease and non-lease components which are accounted for as a single lease component as the Company has elected the practical expedient to combine these components for all leases. As most of the leases do not provide an implicit rate, the Company calculated the “right-of-use” (“ROU”) assets and lease liabilities using its secured incremental borrowing rate at the lease commencement date. As of March 31, 2024 and December 31, 2023, the Company had the following ROU assets and lease liabilities within its Condensed Consolidated Balance Sheets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, December 31, ​ ​ ​ ​ 2024 ​ 2023 Assets Balance Sheet Classification ​ ​ Operating lease right-of-use assets Other noncurrent assets ​ $ 8,960 ​ $ 9,626 Financing lease right-of-use assets Other noncurrent assets ​ ​ 1,297 ​ ​ 1,621 Total Lease Assets ​ ​ ​ $ 10,257 ​ $ 11,247 ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities ​ Balance Sheet Classification ​ ​ ​ ​ ​ ​ Financing lease liabilities - current ​ Accrued expenses and other current liabilities ​ $ 2,866 ​ $ 1,041 Operating lease liabilities - current ​ Accrued expenses and other current liabilities ​ ​ 2,807 ​ ​ 2,789 Financing lease liabilities - long-term ​ Other noncurrent liabilities ​ ​ - ​ ​ 2,079 Operating lease liabilities - long-term ​ Other noncurrent liabilities ​ ​ 6,604 ​ ​ 7,351 ​ ​ ​ ​ $ 12,277 ​ $ 13,260 ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average remaining lease term in years ​ ​ ​ ​ ​ ​ ​ ​ Operating leases ​ ​ ​ ​ 3.07 ​ ​ 3.32 Finance leases ​ ​ ​ ​ 1.00 ​ ​ 1.25 ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average discount rate ​ ​ ​ ​ ​ ​ ​ ​ Operating leases ​ ​ ​ ​ 5.5% ​ ​ 5.5% Finance leases ​ ​ ​ ​ 6.4% ​ ​ 6.4% ​ Information related to leases was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ ​ ​ 2024 ​ 2023 ​ ​ ​ ​ ​ ​ ​ ​ Operating lease information: ​ ​ ​ ​ ​ ​ Operating lease cost ​ ​ $ 803 ​ ​ $ 831 Operating cash flows from operating leases ​ 866 ​ ​ ​ 876 ​ ​ ​ ​ ​ ​ ​ ​ ​ Financing lease information: ​ ​ ​ ​ ​ ​ Financing lease cost ​ ​ $ 393 ​ ​ $ 393 Operating cash flows from financing leases ​ ​ 303 ​ ​ ​ 303 ​ ​ ​ Future minimum lease payments under non-cancellable leases as of March 31, 2024 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating ​ ​ Finance Year ​ Leases ​ ​ Leases ​ (In thousands) 2024 ​ $ 2,415 ​ ​ $ 908 2025 ​ 3,266 ​ ​ 2,111 2026 ​ 3,080 ​ ​ — 2027 ​ 1,533 ​ ​ — 2028 ​ — ​ ​ — Thereafter ​ — ​ ​ — Total minimum lease payments ​ $ 10,294 ​ ​ $ 3,019 Less imputed interest ​ (883) ​ ​ (153) ​ ​ ​ ​ ​ ​ ​ ​ Total lease liabilities ​ $ 9,411 ​ ​ $ 2,866 ​

Subsequent Event

Subsequent Event	3 Months Ended
	Mar. 31, 2024
Subsequent Event.
Subsequent Event	​ 17. Subsequent Event ​ On April 25, 2024, the Company announced the board approval of a quarterly dividend of $1.11 per share for stockholders of record on May 31, 2024, with a payment date of June 14, 2024. The dividend consists of a fixed component of ​ ​

Accounting Policies (Policies)

Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2024
Accounting Policies
Basis of Presentation	The accompanying unaudited condensed consolidated financial statements include the accounts of Arch Resources, Inc. (“Arch Resources”) and its subsidiaries and controlled entities (“Arch” or the “Company”). Unless the context indicates otherwise, the terms “Arch” and the “Company” are used interchangeably in this Quarterly Report on Form 10-Q. The Company’s primary business is the production of metallurgical and thermal coal from underground and surface mines located throughout the United States, for sale to steel producers, utility companies, and industrial accounts both in the United States and around the world. The Company currently operates mining complexes in West Virginia, Wyoming and Colorado. All subsidiaries are wholly owned. Intercompany transactions and accounts have been eliminated in consolidation. The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States for interim financial reporting and U.S. Securities and Exchange Commission regulations. In the opinion of management, all adjustments, consisting of normal, recurring accruals considered necessary for a fair presentation, have been included. Results of operations for the three months ended March 31, 2024 are not necessarily indicative of results to be expected for the year ending December 31, 2024. These financial statements should be read in conjunction with the audited financial statements and related notes as of and for the year ended December 31, 2023 included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023 filed with the U.S. Securities and Exchange Commission. Certain amounts have been reclassified to conform to the current period's presentation.
Recently Adopted Accounting Guidance	Recently Adopted Accounting Guidance There is no recently issued accounting guidance effective that is expected to have a material impact on the Company’s financial position, results of operations, or liquidity. ​ Recent Accounting Guidance Issued Not Yet Effective ​ In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which includes amendments that further enhance income tax disclosures, primarily through standardization and disaggregation of rate reconciliation categories and income taxes paid by jurisdiction. The amendments are effective for the Company’s annual periods beginning June 1, 2025, with early adoption permitted, and should be applied either prospectively or retrospectively. The Company is currently evaluating the ASU to determine its impact on the Company’s disclosures. ​

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Loss) (Tables)	3 Months Ended
	Mar. 31, 2024
Accumulated Other Comprehensive Income (Loss).
Schedule of Accumulated Other Comprehensive Income (Loss)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pension, ​ ​ ​ ​ ​ ​ Postretirement ​ ​ ​ ​ Accumulated ​ ​ and Other Post- ​ ​ ​ ​ Other ​ ​ Employment ​ Available-for- ​ Comprehensive ​ ​ Benefits ​ Sale Securities ​ Income (loss) ​ ​ ​ ​ ​ ​ ​ ​ ​ Balances at December 31, 2023 ​ $ 38,783 ​ $ (1) $ 38,782 Unrealized gains ​ — ​ 5 5 Amounts reclassified from accumulated other comprehensive income ​ (2,006) ​ (9) (2,015) Tax effect ​ ​ 427 ​ ​ 1 ​ ​ 428 Balances at March 31, 2024 ​ $ 37,204 ​ $ (4) $ 37,200
Schedule of Comprehensive Income Reclassifications	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, Line Item in the Condensed Consolidated Details About AOCI Components 2024 2023 Income Statements ​ ​ (In thousands) ​ ​ Pension, postretirement and other post-employment benefits ​ ​ ​ ​ ​ ​ ​ ​ Amortization of actuarial gains, net 1 ​ $ 2,006 ​ $ 2,858 Non-service related pension and postretirement benefit credits Amortization of prior service credits ​ ​ — ​ ​ 37 ​ Non-service related pension and postretirement benefit credits ​ ​ (427) ​ (636) Provision for income taxes ​ ​ $ 1,579 ​ $ 2,259 Net of tax ​ ​ ​ ​ ​ ​ ​ ​ ​ Available-for-sale securities 2 ​ $ 9 ​ $ (22) Interest and investment income ​ ​ (1) ​ 5 Provision for income taxes ​ ​ $ 8 ​ $ (17) Net of tax 1 2

Inventories (Tables)

Inventories (Tables)	3 Months Ended
	Mar. 31, 2024
Inventories
Inventories	​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, December 31, ​ 2024 2023 ​ ​ (In thousands) Coal ​ $ 95,492 ​ $ 99,174 Repair parts and supplies ​ 148,198 ​ 145,087 ​ ​ $ 243,690 ​ $ 244,261

Investments in Available-for-_2

Investments in Available-for-Sale Securities (Tables)	3 Months Ended
	Mar. 31, 2024
Investments in Available-for-Sale Securities
Available-for-sale Securities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2024 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross ​ ​ Allowance ​ ​ ​ ​ ​ ​ ​ ​ Unrealized ​ ​ for - Credit ​ Fair ​ Cost Basis Gains Losses ​ ​ Losses Value ​ ​ (In thousands) Available-for-sale: ​ ​ ​ ​ ​ ​ ​ U.S. government and agency securities ​ $ 31,291 ​ $ 12 ​ $ (7) ​ $ — ​ $ 31,296 Corporate notes and bonds ​ 2,956 ​ 4 ​ (4) ​ — ​ 2,956 Total Investments ​ $ 34,247 ​ $ 16 ​ $ (11) ​ $ — ​ $ 34,252 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2023 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross ​ ​ Allowance ​ ​ ​ ​ ​ ​ ​ ​ Unrealized ​ ​ for - Credit ​ Fair ​ Cost Basis Gains ​ Losses ​ ​ Losses Value ​ (In thousands) Available-for-sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. government and agency securities ​ $ 28,764 ​ $ 14 ​ $ (5) ​ $ — ​ $ 28,773 Corporate notes and bonds ​ 3,951 ​ 1 ​ (1) ​ — ​ 3,951 Total Investments ​ $ 32,715 ​ $ 15 ​ $ (6) ​ $ — ​ $ 32,724

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	3 Months Ended
	Mar. 31, 2024
Accrued Expenses and Other Current Liabilities.
Schedule of Accrued Expenses and Other Current Liabilities	​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, December 31, ​ ​ 2024 ​ 2023 ​ ​ (In thousands) Payroll and employee benefits ​ $ 30,832 ​ $ 37,259 Taxes other than income taxes ​ 44,063 ​ 51,155 Interest ​ 1,372 ​ 2,395 Workers’ compensation ​ 17,775 ​ 18,724 Asset retirement obligations ​ 6,091 ​ 6,089 Other ​ 13,227 ​ 11,995 ​ ​ $ 113,360 ​ $ 127,617

Debt and Financing Arrangemen_2

Debt and Financing Arrangements (Tables)	3 Months Ended
	Mar. 31, 2024
Debt and Financing Arrangements
Schedule of Long-term debt	​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, December 31, ​ ​ 2024 ​ 2023 ​ (In thousands) Term loan due 2025 ($20.0 million face value) ​ $ 20,000 ​ $ — Term loan due 2024 ​ ​ — ​ ​ 3,502 Tax Exempt Bonds ($98.1 million face value) ​ ​ 98,075 ​ ​ 98,075 Other ​ 27,733 ​ 40,529 Debt issuance costs ​ (2,508) ​ (1,511) ​ ​ ​ 143,300 ​ ​ 140,595 Less: current maturities of debt ​ 35,341 ​ 35,343 Long-term debt ​ $ 107,959 ​ $ 105,252

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2024
Fair Value Measurements
Summary of Financial Assets and Liabilities Accounted for at Fair Value	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2024 ​ Total Level 1 Level 2 Level 3 ​ ​ (In thousands) Assets: ​ ​ ​ ​ Investments in marketable securities ​ $ 34,252 ​ $ 31,296 ​ $ 2,956 ​ $ — Fund for asset retirement obligations ​ ​ 144,146 ​ ​ 144,146 ​ ​ — ​ ​ — Total assets ​ $ 178,398 ​ $ 175,442 ​ $ 2,956 ​ $ —

Earnings per Common Share (Tabl

Earnings per Common Share (Tables)	3 Months Ended
	Mar. 31, 2024
Earnings per Common Share
Schedule of Weighted Average Number of Shares	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ ​ 2024 ​ 2023 (In Thousands) ​ ​ ​ Net income attributable to common shares $ 55,953 $ 198,108 Adjustment of interest expense attributable to Convertible Notes ​ ​ — ​ ​ 108 Diluted net income attributable to common stockholders ​ ​ 55,953 ​ ​ 198,216 ​ ​ ​ ​ ​ ​ ​ Basic weighted average shares outstanding ​ ​ 18,347 ​ ​ 17,924 Effect of dilutive securities ​ ​ 428 ​ ​ 1,524 Convertible Notes (a) ​ ​ — ​ ​ 336 Diluted weighted average shares outstanding ​ 18,775 ​ 19,784 (a) Diluted weighted average common shares outstanding includes the dilutive effect had the Company's Convertible Notes been converted at the beginning of the year ended December 31, 2023. If converted by the holder, the Company may settle in cash, shares of the Company's common stock or a combination thereof, at the Company's election. The Capped Call Transaction is anti-dilutive and is excluded from the calculation of diluted earnings per share.

Workers Compensation Expense (T

Workers Compensation Expense (Tables)	3 Months Ended
	Mar. 31, 2024
Workers Compensation Expense
Workers' compensation expense	Workers’ compensation expense consists of the following components: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ ​ 2024 2023 ​ ​ (In thousands) ​ Self-insured occupational disease benefits: ​ ​ Service cost ​ $ 1,278 ​ $ 993 ​ Interest cost (1) ​ 1,565 ​ 1,511 ​ Net amortization (1) ​ (3) ​ (241) ​ Total occupational disease ​ $ 2,840 ​ $ 2,263 ​ Traumatic injury claims and assessments ​ 2,484 ​ 1,690 ​ Total workers’ compensation expense ​ $ 5,324 ​ $ 3,953 ​ (1) In accordance with the adoption of ASU 2017-07, “Compensation-Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost,” these costs are recorded within Nonoperating expenses in the Condensed Consolidated Income Statements on the line item “Non-service related pension and postretirement benefit (credits) costs.”

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	3 Months Ended
	Mar. 31, 2024
Employee Benefit Plans
Schedule of Pension Benefit Costs (Credits)	The following table details the components of pension benefit credit: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ ​ 2024 2023 ​ ​ (In thousands) Interest cost (1) ​ $ 11 ​ $ 1,534 ​ Expected return on plan assets (1) ​ — ​ ​ (1,518) ​ Amortization of prior service credits (1) ​ — ​ (37) ​ Amortization of other actuarial (gains) (1) ​ (22) ​ (195) ​ Net benefit credit ​ $ (11) ​ $ (216) ​ ​ ​ The following table details the components of other postretirement benefit credit: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ ​ 2024 2023 ​ ​ (In thousands) Service cost ​ $ 49 ​ $ 58 ​ Interest cost (1) ​ 605 ​ 674 ​ Amortization of other actuarial gains (1) ​ (1,981) ​ (2,422) ​ Net benefit credit ​ $ (1,327) ​ $ (1,690) ​ (1) In accordance with the adoption of ASU 2017-07, “Compensation-Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost,” these costs are recorded within Nonoperating expenses in the Condensed Consolidated Income Statements on the line item “Non-service related pension and postretirement benefit credits (costs).”

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2024
Segment Information
Schedule of Operating Segment Results	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other and ​ ​ ​ (In thousands) ​ MET ​ Thermal ​ Eliminations ​ Consolidated ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2024 ​ ​ ​ ​ ​ ​ ​ ​ Revenues ​ $ 417,065 ​ $ 263,125 ​ $ — $ 680,190 Adjusted EBITDA ​ 129,536 ​ 930 ​ (27,603) 102,863 Depreciation, depletion and amortization ​ 31,390 ​ 7,168 ​ 262 38,820 Accretion on asset retirement obligation ​ 647 ​ 4,810 ​ 412 5,869 Capital expenditures ​ 37,033 ​ 7,544 ​ 869 45,446 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2023 ​ ​ ​ ​ ​ ​ ​ Revenues ​ $ 536,172 ​ $ 333,759 ​ $ — ​ $ 869,931 Adjusted EBITDA ​ 263,057 ​ 46,255 ​ (31,971) ​ 277,341 Depreciation, depletion and amortization ​ 27,853 ​ 7,408 ​ 218 ​ 35,479 Accretion on asset retirement obligation ​ 615 ​ 4,314 ​ 363 ​ 5,292 Capital expenditures ​ 24,761 ​ 5,493 ​ 287 ​ 30,541
Schedule of Reconciliation of Net Income to Adjusted EBITDA	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, (In thousands) 2024 2023 Net income ​ $ 55,953 ​ $ 198,108 Provision for income taxes ​ ​ 3,719 ​ ​ 37,138 Interest expense, net ​ (1,784) ​ 790 Depreciation, depletion and amortization ​ 38,820 ​ 35,479 Accretion on asset retirement obligations ​ 5,869 ​ 5,292 Non-service related pension and postretirement benefit costs (credits) ​ ​ 286 ​ ​ (592) Net loss resulting from early retirement of debt ​ — ​ 1,126 Adjusted EBITDA ​ $ 102,863 ​ $ 277,341 EBITDA from idled or otherwise disposed operations ​ ​ 3,697 ​ ​ 4,032 Selling, general and administrative expenses ​ ​ 25,587 ​ ​ 26,022 Other ​ ​ (1,681) ​ ​ 1,917 Segment Adjusted EBITDA from coal operations ​ $ 130,466 ​ $ 309,312 ​

Revenue Recognition (Tables)

Revenue Recognition (Tables)	3 Months Ended
	Mar. 31, 2024
Revenue Recognition
Schedule of effects of revenue recognition	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other and ​ ​ ​ ​ ​ MET ​ Thermal ​ Eliminations ​ Consolidated ​ (in thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2024 ​ ​ ​ ​ ​ ​ ​ ​ North America revenues ​ $ 35,584 ​ $ 205,663 ​ $ — ​ $ 241,247 Seaborne revenues ​ 381,481 ​ 57,462 ​ — ​ 438,943 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total revenues ​ $ 417,065 ​ $ 263,125 ​ $ — ​ $ 680,190 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2023 ​ ​ ​ ​ ​ ​ ​ ​ North America revenues ​ $ 71,407 ​ $ 287,259 ​ $ — ​ $ 358,666 Seaborne revenues ​ 464,765 ​ 46,500 ​ — ​ 511,265 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total revenues ​ $ 536,172 ​ $ 333,759 ​ $ — ​ $ 869,931 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2024
Leases
Schedule of right-of-use assets and lease liabilities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, December 31, ​ ​ ​ ​ 2024 ​ 2023 Assets Balance Sheet Classification ​ ​ Operating lease right-of-use assets Other noncurrent assets ​ $ 8,960 ​ $ 9,626 Financing lease right-of-use assets Other noncurrent assets ​ ​ 1,297 ​ ​ 1,621 Total Lease Assets ​ ​ ​ $ 10,257 ​ $ 11,247 ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities ​ Balance Sheet Classification ​ ​ ​ ​ ​ ​ Financing lease liabilities - current ​ Accrued expenses and other current liabilities ​ $ 2,866 ​ $ 1,041 Operating lease liabilities - current ​ Accrued expenses and other current liabilities ​ ​ 2,807 ​ ​ 2,789 Financing lease liabilities - long-term ​ Other noncurrent liabilities ​ ​ - ​ ​ 2,079 Operating lease liabilities - long-term ​ Other noncurrent liabilities ​ ​ 6,604 ​ ​ 7,351 ​ ​ ​ ​ $ 12,277 ​ $ 13,260 ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average remaining lease term in years ​ ​ ​ ​ ​ ​ ​ ​ Operating leases ​ ​ ​ ​ 3.07 ​ ​ 3.32 Finance leases ​ ​ ​ ​ 1.00 ​ ​ 1.25 ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average discount rate ​ ​ ​ ​ ​ ​ ​ ​ Operating leases ​ ​ ​ ​ 5.5% ​ ​ 5.5% Finance leases ​ ​ ​ ​ 6.4% ​ ​ 6.4%
Schedule of Information Related to Leases	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ ​ ​ 2024 ​ 2023 ​ ​ ​ ​ ​ ​ ​ ​ Operating lease information: ​ ​ ​ ​ ​ ​ Operating lease cost ​ ​ $ 803 ​ ​ $ 831 Operating cash flows from operating leases ​ 866 ​ ​ ​ 876 ​ ​ ​ ​ ​ ​ ​ ​ ​ Financing lease information: ​ ​ ​ ​ ​ ​ Financing lease cost ​ ​ $ 393 ​ ​ $ 393 Operating cash flows from financing leases ​ ​ 303 ​ ​ ​ 303
Schedule of Future Minimum Lease Payments	Future minimum lease payments under non-cancellable leases as of March 31, 2024 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating ​ ​ Finance Year ​ Leases ​ ​ Leases ​ (In thousands) 2024 ​ $ 2,415 ​ ​ $ 908 2025 ​ 3,266 ​ ​ 2,111 2026 ​ 3,080 ​ ​ — 2027 ​ 1,533 ​ ​ — 2028 ​ — ​ ​ — Thereafter ​ — ​ ​ — Total minimum lease payments ​ $ 10,294 ​ ​ $ 3,019 Less imputed interest ​ (883) ​ ​ (153) ​ ​ ​ ​ ​ ​ ​ ​ Total lease liabilities ​ $ 9,411 ​ ​ $ 2,866 ​

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Loss) - Schedule of accumulated other comprehensive income (loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Accumulated Other Comprehensive Income (Loss)
Beginning Balance	$ 1,479,456	$ 1,365,580
Tax effect	3,719	37,138
Ending Balance	1,467,448	1,463,994
Accumulated Other Comprehensive Income (loss)
Accumulated Other Comprehensive Income (Loss)
Beginning Balance	38,782	61,429
Unrealized gains	5
Amounts reclassified from accumulated other comprehensive income	(2,015)
Tax effect	428
Ending Balance	37,200	$ 59,158
Pension, Postretirement and Other Post-Employment Benefits
Accumulated Other Comprehensive Income (Loss)
Beginning Balance	38,783
Amounts reclassified from accumulated other comprehensive income	(2,006)
Tax effect	427
Ending Balance	37,204
Available-for-Sale Securities
Accumulated Other Comprehensive Income (Loss)
Beginning Balance	(1)
Unrealized gains	5
Amounts reclassified from accumulated other comprehensive income	(9)
Tax effect	1
Ending Balance	$ (4)

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Income (Loss) - Schedule of reclassifications (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Accumulated Other Comprehensive Income (Loss)
Interest expense	$ (4,316)	$ (4,126)
Net loss resulting from early retirement of debt		1,126
Interest and investment income	6,100	3,336
Total before tax	59,672	235,246
Provision for income taxes	3,719	37,138
Net Income (Loss)	55,953	198,108
Pension, postretirement and other post-employment benefits
Accumulated Other Comprehensive Income (Loss)
Provision for income taxes	427
Available-for-sale securities
Accumulated Other Comprehensive Income (Loss)
Provision for income taxes	1
Reclassification out of Accumulated Other Comprehensive Income | Pension, postretirement and other post-employment benefits
Accumulated Other Comprehensive Income (Loss)
Amortization of actuarial gains, net 1	2,006	2,858
Amortization of prior service credits		37
Provision for income taxes	427	636
Net Income (Loss)	1,579	2,259
Reclassification out of Accumulated Other Comprehensive Income | Available-for-sale securities
Accumulated Other Comprehensive Income (Loss)
Interest and investment income	9	(22)
Provision for income taxes	1	(5)
Net Income (Loss)	$ 8	$ (17)

Inventories (Details)

Inventories (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Inventories
Coal	$ 95,492	$ 99,174
Repair parts and supplies	148,198	145,087
Inventories	243,690	244,261
Allowance for slow-moving and obsolete inventories	$ 1,600	$ 1,600

Investments in Available-for-_3

Investments in Available-for-Sale Securities - Schedule of investments (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Debt Securities, Available-for-sale [Line Items]
Available-for-sale, Cost Basis	$ 34,247	$ 32,715
Available-for-sale, Gross Unrealized Gains	16	15
Available-for-sale, Gross Unrealized Losses	(11)	(6)
Available-for-sale, Fair Value	34,252	32,724
U.S. government and agency securities
Debt Securities, Available-for-sale [Line Items]
Available-for-sale, Cost Basis	31,291	28,764
Available-for-sale, Gross Unrealized Gains	12	14
Available-for-sale, Gross Unrealized Losses	(7)	(5)
Available-for-sale, Fair Value	31,296	28,773
Corporate notes and bonds
Debt Securities, Available-for-sale [Line Items]
Available-for-sale, Cost Basis	2,956	3,951
Available-for-sale, Gross Unrealized Gains	4	1
Available-for-sale, Gross Unrealized Losses	(4)	(1)
Available-for-sale, Fair Value	$ 2,956	$ 3,951

Investments in Available-for-_4

Investments in Available-for-Sale securities (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Investments in Available-for-Sale Securities
Unrealized losses owned for less than 12 months	$ 5.6	$ 2.2
Unrealized losses owed for over a year	$ 0	$ 2.3

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Accrued Expenses and Other Current Liabilities.
Payroll and employee benefits	$ 30,832	$ 37,259
Taxes other than income taxes	44,063	51,155
Interest	1,372	2,395
Workers' compensation	17,775	18,724
Asset retirement obligations	6,091	6,089
Other	13,227	11,995
Accrued expenses and other current liabilities	$ 113,360	$ 127,617

Debt and Financing Arrangemen_3

Debt and Financing Arrangements - Long term debt (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Debt issuance costs	$ (2,508)	$ (1,511)
Total	143,300	140,595
Less: current maturities of debt	35,341	35,343
Long-term debt	107,959	105,252
Term loan due 2025
Debt Instrument [Line Items]
Long-term debt	20,000
Debt instrument, face amount	20,000
Term loan due 2024
Debt Instrument [Line Items]
Long-term debt		3,502
Tax Exempt Bonds
Debt Instrument [Line Items]
Long-term debt	98,075	98,075
Debt instrument, face amount	98,100
Other Debt
Debt Instrument [Line Items]
Long-term debt	$ 27,733	$ 40,529

Debt and Financing Arrangemen_4

Debt and Financing Arrangements (Details) $ in Thousands							3 Months Ended
	Feb. 16, 2024 shares	Feb. 08, 2024 USD ($)	Aug. 03, 2022 USD ($)	Jul. 29, 2021 USD ($) M	Nov. 03, 2020 USD ($)	Jul. 02, 2020 USD ($)	Mar. 31, 2024 USD ($) shares	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($)	Aug. 02, 2022 USD ($)	Mar. 04, 2021 USD ($)
Debt Instrument [Line Items]
Payments on term loan							$ 3,502	$ 750
Receipt of shares from the exercise of capped call | shares	315,721						315,721
Proceeds from issuance of debt							$ 20,000
Restricted cash							1,100	$ 1,100	$ 1,100
Debt financing costs		$ 1,500					1,500
Outstanding debt							143,300		$ 140,595
New Term Loan Debt Facility | Secured Debt
Debt Instrument [Line Items]
Term loan, face value		20,000
Amortization payments		$ 3,300
Term loan due 2025
Debt Instrument [Line Items]
Term loan, face value							20,000
Total net leverage		2
Term of financial maintenance covenants, maximum total net leverage ratio		12 months
Maximum consolidated EBITDA to consolidated interest expense ratio		3.50
Term of financial maintenance covenants on consolidated EBITDA		12 months
Customary mandatory prepayment events		100%
Term loan due 2025 | Minimum
Debt Instrument [Line Items]
Financial maintenance covenant for liquidity		$ 100,000
Term loan due 2025 | SOFR
Debt Instrument [Line Items]
Applicable margin on interest rate		3%
Adjustment to basis spread on variable rate		10%
Floor, basis spread on variable rate		0%
Term loan due 2025 | Base Rate
Debt Instrument [Line Items]
Applicable margin on interest rate		2%
Term loan due 2024
Debt Instrument [Line Items]
Payments on term loan		$ 3,500
Accounts Receivable Securitization Facility | Line of Credit | Secured Debt
Debt Instrument [Line Items]
Current borrowing capacity							98,100
Letters of credit outstanding							51,900
Accounts Receivable Securitization Facility | Regions Bank | Line of Credit | Secured Debt
Debt Instrument [Line Items]
Current borrowing capacity			$ 150,000							$ 110,000
Inventory-Based Revolving Credit Facility
Debt Instrument [Line Items]
Covenant amount							23,800
Inventory-Based Revolving Credit Facility | Regions Bank | Line of Credit | Secured Debt
Debt Instrument [Line Items]
Term loan, face value			$ 50,000
Letters of credit outstanding							26,200
Borrowing base percentage, coal inventory			85
Borrowing base percentage, parts and supplies inventory			85
Borrowing base, percentage of clause			35
Percent of eligible cash			100%
Covenant amount			$ 100,000
Equipment financing arrangement | Secured Debt
Debt Instrument [Line Items]
Term loan, face value				$ 23,500
Number of monthly payments | M				42
Interest rate				7.35%
Tax Exempt Bonds
Debt Instrument [Line Items]
Term loan, face value							98,100
Series 2020 Tax Exempt Bonds
Debt Instrument [Line Items]
Term loan, face value						$ 53,100
Interest rate						5%
Mandatory tender percentage						100%
Series 2021 Tax Exempt Bonds
Debt Instrument [Line Items]
Term loan, face value											$ 45,000
Interest rate											4.125%
Convertible Notes
Debt Instrument [Line Items]
Term loan, face value					$ 155,300
Interest rate					5.25%
Net proceeds of convertible debt					$ 132,700
Principal amount of convertible notes							13,200
Cash on convertible notes							58,400
Deferred Offering Costs					5,100
Loss on debt conversion							$ 1,100
Capped Call Transactions
Debt Instrument [Line Items]
Capped call, transaction cost					$ 17,500

Income Taxes (Details)

Income Taxes (Details)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Taxes
Effective income tax rate (as a percent)	6.20%	15.80%
U.S. federal statutory rate (as percent)	21%	21%

Fair Value Measurements - Finan

Fair Value Measurements - Financial assets and liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Assets:
Investments in marketable securities	$ 34,252	$ 32,724
Fund for asset retirement obligations	144,146
Total assets	178,398
Level 1
Assets:
Investments in marketable securities	31,296
Fund for asset retirement obligations	144,146
Total assets	175,442
Level 2
Assets:
Investments in marketable securities	2,956
Fund for asset retirement obligations	0
Total assets	2,956
Level 3
Assets:
Investments in marketable securities	0
Fund for asset retirement obligations	0
Total assets	$ 0

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Contribution to fund asset retirement obligations	$ 1,881	$ 1,141
Fair value of debt, including amounts classified as current	145,800		$ 142,100
Asset retirement obligations
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Contribution to fund asset retirement obligations	$ 1,900

Earnings per Common Share (Deta

Earnings per Common Share (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Earnings per Common Share
Net income attributable to common shares	$ 55,953	$ 198,108
Adjustment of interest expense attributable to Convertible Notes		108
Diluted net income attributable to common shareholders	$ 55,953	$ 198,216
Weighted average shares outstanding:
Basic weighted average shares outstanding (in shares)	18,347	17,924
Effect of dilutive securities (in shares)	428	1,524
Convertible Notes (in shares)		336
Diluted weighted average shares outstanding (in shares)	18,775	19,784

Workers Compensation Expense (D

Workers Compensation Expense (Details) - USD ($) $ in Millions		1 Months Ended
	Jan. 18, 2023	Feb. 29, 2020
Workers Compensation Expense
Self-insured operators must post security percent	120%
Additional collateral amount		$ 71.1
Number of days required to submit additional collateral to retain self-insurance status		30 days

Workers Compensation Expense -

Workers Compensation Expense - Worker's compensation expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Total workers' compensation expense
Accrued Workers' Compensation [Line Items]
Total workers' compensation expense	$ 5,324	$ 3,953
Occupational disease
Accrued Workers' Compensation [Line Items]
Service cost	1,278	993
Interest cost	1,565	1,511
Amortization of other actuarial (gains)	(3)	(241)
Net benefit credit	2,840	2,263
Traumatic injury claims and assessments
Accrued Workers' Compensation [Line Items]
Traumatic injury claims and assessments	$ 2,484	$ 1,690

Employee Benefit Plans - Schedu

Employee Benefit Plans - Schedule of net benefit credit (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 11	$ 1,534
Expected return on plan assets	0	(1,518)
Amortization of prior service credits	0	$ (37)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Amortization of Prior Service Cost (Credit), Statement of Income or Comprehensive Income [Extensible Enumeration]		Pension and Other Postretirement Benefits Cost (Reversal of Cost)
Amortization of other actuarial (gains)	(22)	$ (195)
Net benefit credit	(11)	(216)
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	49	58
Interest cost	605	674
Amortization of other actuarial (gains)	$ (1,981)	$ (2,422)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Amortization of Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Pension and Other Postretirement Benefits Cost (Reversal of Cost)	Pension and Other Postretirement Benefits Cost (Reversal of Cost)
Net benefit credit	$ (1,327)	$ (1,690)

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Loss Contingencies [Line Items]
Surety Bonds Outstanding	$ 500,100
Cash collateral for surety bond	5,600
Contribution to fund asset retirement obligations	1,881	$ 1,141
Fund for asset retirement obligations	144,146		$ 142,266
Securitization and Inventory Facilities
Loss Contingencies [Line Items]
Letters of credit outstanding	78,100
Asset retirement obligations
Loss Contingencies [Line Items]
Surety Bonds Outstanding	403,200
Cash collateral for surety bond	600
Reclamation-related obligations	266,300
Contribution to fund asset retirement obligations	1,900
Fund for asset retirement obligations	$ 144,100

Segment Information - Schedule

Segment Information - Schedule of operating segment results (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($) item	Mar. 31, 2023 USD ($)
Segment Reporting Information [Line Items]
Number of distinct lines of business | item	2
Revenues	$ 680,190	$ 869,931
Adjusted EBITDA	102,863	277,341
Depreciation, depletion and amortization	38,820	35,479
Accretion on asset retirement obligation	5,869	5,292
Capital expenditures	45,446	30,541
Operating Segments | MET
Segment Reporting Information [Line Items]
Revenues	417,065	536,172
Adjusted EBITDA	129,536	263,057
Depreciation, depletion and amortization	31,390	27,853
Accretion on asset retirement obligation	647	615
Capital expenditures	37,033	24,761
Operating Segments | Thermal
Segment Reporting Information [Line Items]
Revenues	263,125	333,759
Adjusted EBITDA	930	46,255
Depreciation, depletion and amortization	7,168	7,408
Accretion on asset retirement obligation	4,810	4,314
Capital expenditures	7,544	5,493
Corporate, Other and Eliminations
Segment Reporting Information [Line Items]
Revenues	0	0
Adjusted EBITDA	(27,603)	(31,971)
Depreciation, depletion and amortization	262	218
Accretion on asset retirement obligation	412	363
Capital expenditures	$ 869	$ 287

Segment Information - Reconcili

Segment Information - Reconciliation segment income to net income (loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment Information
Net Income (Loss)	$ 55,953	$ 198,108
Provision for income taxes	3,719	37,138
Interest expense, net	(1,784)	790
Depreciation, depletion and amortization	38,820	35,479
Accretion on asset retirement obligation	5,869	5,292
Non-service related pension and postretirement benefit costs (credits)	286	(592)
Net loss resulting from early retirement of debt		1,126
Adjusted EBITDA	102,863	277,341
EBITDA from idled or otherwise disposed operations	3,697	4,032
Selling, general and administrative expenses	25,587	26,022
Other	(1,681)	1,917
Segment Adjusted EBITDA from coal operations	$ 130,466	$ 309,312

Revenue Recognition - Schedule

Revenue Recognition - Schedule of revenues (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disaggregation of Revenue [Line Items]
Revenues	$ 680,190	$ 869,931
North America revenues
Disaggregation of Revenue [Line Items]
Revenues	241,247	358,666
Seaborne revenues
Disaggregation of Revenue [Line Items]
Revenues	438,943	511,265
Operating Segments | MET
Disaggregation of Revenue [Line Items]
Revenues	417,065	536,172
Operating Segments | MET | North America revenues
Disaggregation of Revenue [Line Items]
Revenues	35,584	71,407
Operating Segments | MET | Seaborne revenues
Disaggregation of Revenue [Line Items]
Revenues	381,481	464,765
Operating Segments | Thermal
Disaggregation of Revenue [Line Items]
Revenues	263,125	333,759
Operating Segments | Thermal | North America revenues
Disaggregation of Revenue [Line Items]
Revenues	205,663	287,259
Operating Segments | Thermal | Seaborne revenues
Disaggregation of Revenue [Line Items]
Revenues	57,462	46,500
Corporate, Other and Eliminations
Disaggregation of Revenue [Line Items]
Revenues	0	0
Corporate, Other and Eliminations | North America revenues
Disaggregation of Revenue [Line Items]
Revenues	0	0
Corporate, Other and Eliminations | Seaborne revenues
Disaggregation of Revenue [Line Items]
Revenues	$ 0	$ 0

Revenue Recognition (Details)

Revenue Recognition (Details) T in Millions	Mar. 31, 2024 T
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation (in tons)	40.9
Remaining performance obligation, variable price contracts (in tons)	5.2
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations, fixed price contracts (in tons)	66.5
Remaining performance obligation, variable price contracts (in tons)	1.7

Leases (Narrative) (Details)

Leases (Narrative) (Details)	Mar. 31, 2024
Minimum
Lessee, Lease, Description [Line Items]
Operating lease, remaining lease terms	1 year
Maximum
Lessee, Lease, Description [Line Items]
Operating lease, remaining lease terms	3 years

Leases - Lease assets and liabi

Leases - Lease assets and liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Assets
Operating lease right-of-use assets	$ 8,960	$ 9,626
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Other Assets, Noncurrent	Other Assets, Noncurrent
Financing lease right-of-use assets	$ 1,297	$ 1,621
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Other Assets, Noncurrent	Other Assets, Noncurrent
Total Lease Assets	$ 10,257	$ 11,247
Liabilities
Financing lease liabilities - current	$ 2,866	$ 1,041
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	Accrued Liabilities, Current	Accrued Liabilities, Current
Operating lease liabilities - current	$ 2,807	$ 2,789
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Accrued Liabilities, Current	Accrued Liabilities, Current
Financing lease liabilities - long-term		$ 2,079
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]		Other Liabilities, Noncurrent
Operating lease liabilities - long-term	$ 6,604	$ 7,351
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Other Liabilities, Noncurrent	Other Liabilities, Noncurrent
Total Lease Liabilities	$ 12,277	$ 13,260

Leases - Weighted average lease

Leases - Weighted average lease term and discount rate (Details)	Mar. 31, 2024	Dec. 31, 2023
Leases
Weighted average remaining lease term in years - Operating leases	3 years 25 days	3 years 3 months 25 days
Weighted average remaining lease term in years - Finance leases	1 year	1 year 3 months
Weighted average discount rate - Operating leases	5.50%	5.50%
Weighted average discount rate - Finance leases	6.40%	6.40%

Leases - Other information rela

Leases - Other information related to leases (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Lease information:
Operating lease cost	$ 803	$ 831
Operating cash flows from operating leases	866	876
Financing lease cost	393	393
Operating cash flows from financing leases	$ 303	$ 303

Leases - Future minimum lease p

Leases - Future minimum lease payments (Details) $ in Thousands	Mar. 31, 2024 USD ($)
Operating Leases
2024	$ 2,415
2025	3,266
2026	3,080
2027	1,533
Total minimum lease payments	10,294
Less imputed interest	(883)
Total operating lease liabilities	9,411
Finance Leases
2024	908
2025	2,111
Total minimum lease payments	3,019
Less imputed interest	(153)
Total finance lease liabilities	$ 2,866

Subsequent Event (Details)

Subsequent Event (Details) - Subsequent Event	Apr. 25, 2024 $ / shares
Subsequent Event [Line Items]
Quarterly dividend	$ 1.11
Fixed dividend	0.25
Variable dividend	$ 0.86

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ 55,953	$ 198,108

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Mar. 31, 2024 shares
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	During the three months ended March 31, 2024, the following officers of the Company adopted “Rule 10b5-1 trading arrangements” as defined in Item 408 of Regulation S-K, as described in the table below: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Type of ​ ​ ​ Expiration ​ ​ ​ ​ Total Shares Name and Title ​ Trading Agreement ​ Date Adopted ​ Date ​ Duration 1 ​ To be Sold 2 Rosemary L. Klein , Senior Vice President - Law, General Counsel and Secretary Rule 10b5-1 Trading Arrangement ​ ​ 3/12/2024 1/31/2025 ​ 326 days ​ ​ Up to 8,100 ​ ​ 1. Each Rule 10b5-1 trading arrangement permits transactions through and including the earlier to occur of (a) the completion of all sales or (b) the expiration date listed in the table. ​ 2. Represents the maximum number of shares that could potentially be sold pursuant to the Rule 10b5-1 trading arrangement, including sales made in connection with the vesting of future equity awards. Accordingly, in calculating this amount, we have not considered any potential reductions in shares available to be sold due to tax withholdings at the time such equity awards vest, and, for performance-based awards, we have assumed such awards will vest at maximum value. ​ Other than as discussed above, during the three months ended March 31, 2024, no director or officer of the Company adopted or terminated a “Rule 10b5-1 trading arrangement” or “non-Rule 10b5-1 trading arrangement,” as each term is defined in Item 408 of Regulation S-K.
Rosemary L. Klein
Trading Arrangements, by Individual
Name	Rosemary L. Klein
Title	Senior Vice President - Law, General Counsel and Secretary
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	3/12/2024
Arrangement Duration	326 days
Aggregate Available	8,100
Expiration Date	1/31/2025