Alpha Metallurgical Resources (AMR) 10-Q 5 Nov 21 2021 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2021	Oct. 31, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
Document Transition Report	false
Entity File Number	001-38735
Entity Registrant Name	ALPHA METALLURGICAL RESOURCES, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	81-3015061
Entity Address, Address Line One	340 Martin Luther King Jr. Blvd.
Entity Address, City or Town	Bristol
Entity Address, State or Province	TN
Entity Address, Postal Zip Code	37620
City Area Code	423
Local Phone Number	573-0300
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Title of 12(b) Security	Common Stock
Trading Symbol	AMR
Security Exchange Name	NYSE
Entity Common Stock, Shares Outstanding		18,400,443
Entity Central Index Key	0001704715
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Amendment Flag	false

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenues:
Coal revenues	$ 647,129	$ 335,189	$ 1,426,039	$ 1,089,764
Other revenues	1,712	403	4,330	2,572
Total revenues	648,841	335,592	1,430,369	1,092,336
Costs and expenses:
Cost of coal sales (exclusive of items shown separately below)	488,169	309,693	1,182,360	979,180
Depreciation, depletion and amortization	24,519	49,236	80,261	143,921
Accretion on asset retirement obligations	6,674	6,737	19,970	19,945
Amortization of acquired intangibles, net	2,980	2,074	9,402	4,466
Asset impairment and restructuring	0	(226)	(561)	53,981
Selling, general and administrative expenses (exclusive of depreciation, depletion and amortization shown separately above)	15,264	14,501	44,891	42,010
Total other operating loss (income):
Mark-to-market adjustment for acquisition-related obligations	11,676	3,624	18,009	(13,425)
Other income	(457)	(1,310)	(5,290)	(2,023)
Total costs and expenses	548,825	384,329	1,349,042	1,228,055
Income (loss) from operations	100,016	(48,737)	81,327	(135,719)
Other (expense) income:
Interest expense	(17,338)	(18,746)	(53,290)	(56,238)
Interest income	54	376	322	6,874
Equity loss in affiliates	(643)	(1,295)	(1,161)	(3,085)
Miscellaneous income (loss), net	1,812	(131)	5,425	(452)
Total other expense, net	(16,115)	(19,796)	(48,704)	(52,901)
Income (loss) from continuing operations before income taxes	83,901	(68,533)	32,623	(188,620)
Income tax (expense) benefit	(208)	45	(211)	2,200
Net income (loss) from continuing operations	83,693	(68,488)	32,412	(186,420)
Discontinued operations:
Loss from discontinued operations before income taxes	(429)	(149)	(1,067)	(160,326)
Loss from discontinued operations	(429)	(149)	(1,067)	(160,326)
Net income (loss)	$ 83,264	$ (68,637)	$ 31,345	$ (346,746)
Basic income (loss) per common share:
Income (loss) from continuing operations (in dollars per share)	$ 4.54	$ (3.74)	$ 1.76	$ (10.19)
Loss from discontinued operations (in dollars per share)	(0.03)	(0.01)	(0.06)	(8.77)
Net income (loss) (in dollars per share)	4.51	(3.75)	1.70	(18.96)
Diluted income (loss) per common share:
Income (loss) from continuing operations (in dollars per share)	4.43	(3.74)	1.73	(10.19)
Loss from discontinued operations (in dollars per share)	(0.03)	(0.01)	(0.06)	(8.77)
Net income (loss) (in dollars per share)	$ 4.40	$ (3.75)	$ 1.67	$ (18.96)
Weighted average shares - basic (in shares)	18,445,709	18,319,947	18,426,639	18,290,346
Weighted average shares - diluted (in shares)	18,913,352	18,319,947	18,783,643	18,290,346

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Other Comprehensive Income [Abstract]
Net income (loss)	$ 83,264	$ (68,637)	$ 31,345	$ (346,746)
Employee benefit plans:
Amortization of and adjustments to employee benefit costs	1,413	1,133	13,077	(9,998)
Income tax expense	0	0	0	0
Total other comprehensive income (loss), net of tax	1,413	1,133	13,077	(9,998)
Total comprehensive income (loss)	$ 84,677	$ (67,504)	$ 44,422	$ (356,744)

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 78,283	$ 139,227
Trade accounts receivable, net of allowance for doubtful accounts of $325 and $293 as of September 30, 2021 and December 31, 2020	335,287	145,670
Inventories, net	124,534	108,051
Prepaid expenses and other current assets	31,723	106,252
Current assets - discontinued operations	1,391	10,935
Total current assets	571,218	510,135
Property, plant, and equipment, net of accumulated depreciation and amortization of $436,205 and $382,423 as of September 30, 2021 and December 31, 2020	356,305	363,620
Owned and leased mineral rights, net of accumulated depletion and amortization of $48,968 and $35,143 as of September 30, 2021 and December 31, 2020	449,901	463,250
Other acquired intangibles, net of accumulated amortization of $31,349 and $25,700 as of September 30, 2021 and December 31, 2020	78,547	88,196
Long-term restricted cash	84,001	96,033
Other non-current assets	126,502	149,382
Non-current assets - discontinued operations	9,477	9,473
Total assets	1,675,951	1,680,089
Current liabilities:
Current portion of long-term debt	7,976	28,830
Trade accounts payable	90,335	58,413
Acquisition-related obligations – current	26,266	19,099
Accrued expenses and other current liabilities	160,732	140,406
Current liabilities - discontinued operations	7,095	12,306
Total current liabilities	292,404	259,054
Long-term debt	497,191	553,697
Acquisition-related obligations - long-term	18,966	20,768
Workers’ compensation and black lung obligations	228,858	230,081
Pension obligations	191,888	218,671
Asset retirement obligations	141,925	140,074
Deferred income taxes	479	480
Other non-current liabilities	29,403	28,072
Non-current liabilities - discontinued operations	26,740	29,090
Total liabilities	1,427,854	1,479,987
Commitments and Contingencies (Note 16)
Stockholders’ Equity
Preferred stock - par value $0.01, 5.0 million shares authorized, none issued	0	0
Common stock - par value $0.01, 50.0 million shares authorized, 20.8 million issued and 18.4 million outstanding at September 30, 2021 and 20.6 million issued and 18.3 million outstanding at December 31, 2020	208	206
Additional paid-in capital	783,781	779,424
Accumulated other comprehensive loss	(98,908)	(111,985)
Treasury stock, at cost: 2.4 million shares at September 30, 2021 and 2.3 million shares at December 31, 2020	(107,800)	(107,014)
Accumulated deficit	(329,184)	(360,529)
Total stockholders’ equity	248,097	200,102
Total liabilities and stockholders’ equity	$ 1,675,951	$ 1,680,089

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - Parenthetical - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 325	$ 293
Property, plant and equipment, accumulated amortization, depreciation and amortization	436,205	382,423
Owned and lease mineral rights, accumulated depletion and amortization	48,968	35,143
Other acquired intangibles, accumulated amortization	$ 31,349	$ 25,700
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	50,000,000	50,000,000
Common stock, shares issued (in shares)	20,800,000	20,600,000
Common stock, shares outstanding (in shares)	18,400,000	18,300,000
Treasury stock, shares at cost (in shares)	2,400,000	2,300,000

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Operating activities:
Net income (loss)	$ 31,345	$ (346,746)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, depletion and amortization	80,261	154,466
Amortization of acquired intangibles, net	9,402	5,180
Accretion of acquisition-related obligations discount	1,004	2,882
Amortization of debt issuance costs and accretion of debt discount	9,351	11,087
Mark-to-market adjustment for acquisition-related obligations	18,009	(13,425)
Gain on disposal of assets	(5,342)	(2,179)
Asset impairment and restructuring	(561)	221,453
Accretion on asset retirement obligations	19,970	23,806
Employee benefit plans, net	6,685	15,135
Deferred income taxes	(1)	33,011
Stock-based compensation	4,351	4,200
Equity loss in affiliates	1,161	3,085
Other, net	(4,381)	(5,356)
Changes in operating assets and liabilities	(100,681)	(33,566)
Net cash provided by operating activities	70,573	73,033
Investing activities:
Capital expenditures	(60,386)	(118,896)
Proceeds on disposal of assets	7,471	3,131
Purchases of investment securities	(15,474)	(18,618)
Maturity of investment securities	10,508	12,678
Capital contributions to equity affiliates	(4,473)	(3,196)
Other, net	52	68
Net cash used in investing activities	(62,302)	(124,833)
Financing activities:
Proceeds from borrowings on long-term debt	0	57,500
Repurchases of long-term debt	(18,415)	0
Principal repayments of long-term debt	(61,869)	(58,315)
Principal repayments of financing lease obligations	(1,527)	(2,291)
Debt issuance costs	(319)	0
Common stock repurchases and related expenses	(786)	(171)
Net cash used in financing activities	(82,916)	(3,277)
Net decrease in cash and cash equivalents and restricted cash	(74,645)	(55,077)
Cash and cash equivalents and restricted cash at beginning of period	244,571	347,680
Cash and cash equivalents and restricted cash at end of period	169,926	292,603
Reconciliation of Cash and Cash Equivalents and Restricted Cash
Cash and cash equivalents	78,283	161,434
Short-term restricted cash (included in prepaid expenses and other current assets)	7,642	7,104
Long-term restricted cash	84,001	124,065
Total cash and cash equivalents and restricted cash shown in the Condensed Consolidated Statements of Cash Flows	$ 169,926	$ 292,603

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Cumulative effect	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Treasury Stock at Cost	Retained Earnings (Deficit)	Retained Earnings (Deficit)Cumulative effect
Beginning balance at Dec. 31, 2019	$ 696,122	$ (440)	$ 205	$ 775,707	$ (58,616)	$ (107,984)	$ 86,810	$ (440)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(39,808)						(39,808)
Other comprehensive income (loss), net	(4,010)				(4,010)
Stock-based compensation and net issuance of common stock for share vesting	900			900
Common stock reissuances, repurchases and related expenses	1,071					1,071
Ending balance at Mar. 31, 2020	653,835		205	776,607	(62,626)	(106,913)	46,562
Beginning balance at Dec. 31, 2019	696,122	$ (440)	205	775,707	(58,616)	(107,984)	86,810	$ (440)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(346,746)
Other comprehensive income (loss), net	(9,998)
Ending balance at Sep. 30, 2020	342,968		206	778,728	(68,614)	(106,976)	(260,376)
Beginning balance at Mar. 31, 2020	653,835		205	776,607	(62,626)	(106,913)	46,562
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(238,301)						(238,301)
Other comprehensive income (loss), net	(7,121)				(7,121)
Stock-based compensation and net issuance of common stock for share vesting	1,044		1	1,043
Common stock reissuances, repurchases and related expenses	(42)					(42)
Ending balance at Jun. 30, 2020	409,415		206	777,650	(69,747)	(106,955)	(191,739)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(68,637)						(68,637)
Other comprehensive income (loss), net	1,133				1,133
Stock-based compensation and net issuance of common stock for share vesting	1,078			1,078
Common stock reissuances, repurchases and related expenses	(21)					(21)
Ending balance at Sep. 30, 2020	342,968		206	778,728	(68,614)	(106,976)	(260,376)
Beginning balance at Dec. 31, 2020	200,102		206	779,424	(111,985)	(107,014)	(360,529)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(32,928)						(32,928)
Other comprehensive income (loss), net	1,484				1,484
Stock-based compensation and net issuance of common stock for share vesting	2,183		1	2,182
Common stock reissuances, repurchases and related expenses	(680)					(680)
Ending balance at Mar. 31, 2021	170,161		207	781,606	(110,501)	(107,694)	(393,457)
Beginning balance at Dec. 31, 2020	200,102		206	779,424	(111,985)	(107,014)	(360,529)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	31,345
Other comprehensive income (loss), net	13,077
Ending balance at Sep. 30, 2021	248,097		208	783,781	(98,908)	(107,800)	(329,184)
Beginning balance at Mar. 31, 2021	170,161		207	781,606	(110,501)	(107,694)	(393,457)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(18,991)						(18,991)
Other comprehensive income (loss), net	10,180				10,180
Stock-based compensation and net issuance of common stock for share vesting	981		1	980
Ending balance at Jun. 30, 2021	162,331		208	782,586	(100,321)	(107,694)	(412,448)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	83,264						83,264
Other comprehensive income (loss), net	1,413				1,413
Stock-based compensation and net issuance of common stock for share vesting	1,189			1,189
Common stock reissuances, repurchases and related expenses	(106)					(106)
Warrant exercises	6			6
Ending balance at Sep. 30, 2021	$ 248,097		$ 208	$ 783,781	$ (98,908)	$ (107,800)	$ (329,184)

Business and Basis of Presentat

Business and Basis of Presentation	9 Months Ended
	Sep. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business and Basis of Presentation	Business and Basis of Presentation Business Alpha Metallurgical Resources, Inc. (“Alpha” or the “Company”) is a Tennessee-based mining company with operations across Virginia and West Virginia. With customers across the globe, high-quality reserves and significant port capacity, Alpha is a leading U.S. supplier of metallurgical products for the steel industry. Basis of Presentation Together, the condensed consolidated statements of operations, comprehensive loss, balance sheets, cash flows and stockholders’ equity for the Company are referred to as the “Condensed Consolidated Financial Statements.” The Condensed Consolidated Financial Statements are also referenced across periods as “Condensed Consolidated Statements of Operations,” “Condensed Consolidated Statements of Comprehensive Loss,” “Condensed Consolidated Balance Sheets,” “Condensed Consolidated Statements of Cash Flows,” and “Condensed Consolidated Statements of Stockholders’ Equity.” The Company’s former Northern Appalachia (“NAPP”) operations results of operations and financial position are reported as discontinued operations in the Condensed Consolidated Financial Statements. The historical information in the accompanying Notes to the Condensed Consolidated Financial Statements has been restated to reflect the effects of the Company’s former NAPP operations being reported as discontinued operations in the Condensed Consolidated Financial Statements. Refer to Note 2 for further information on discontinued operations. The Condensed Consolidated Financial Statements include all wholly-owned subsidiaries’ results of operations for the three and nine months ended September 30, 2021 and 2020. All significant intercompany transactions have been eliminated in consolidation. The accompanying interim Condensed Consolidated Financial Statements are unaudited and have been prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”) and in accordance with the rules and regulations of the United States Securities and Exchange Commission (“SEC”) for Form 10-Q. Such rules and regulations allow the omission of certain information and footnote disclosures normally included in the financial statements prepared in accordance with U.S. GAAP as long as the financial statements are not misleading. In the opinion of management, these interim Condensed Consolidated Financial Statements reflect all normal and recurring adjustments necessary for a fair presentation of the results for the periods presented. Results of operations for the three and nine months ended September 30, 2021 are not necessarily indicative of the results to be expected for the year ending December 31, 2021 or any other period. These interim Condensed Consolidated Financial Statements should be read in conjunction with the Company’s Consolidated Financial Statements and related notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020. Reclassifications Certain amounts in the prior year Condensed Consolidated Statements of Cash Flows have been reclassified to conform to the current year presentation. Liquidity Risks and Uncertainties The Company believes it will have sufficient liquidity to meet its working capital requirements, anticipated capital expenditures, debt service requirements, acquisition-related obligations, and reclamation obligations for the 12 months subsequent to the issuance of these financial statements. However, the Company may need to raise additional funds if market conditions deteriorate and may not be able to do so in a timely fashion, or at all. The Company relies on a number of assumptions in budgeting for future activities. These include the costs for mine development to sustain capacity of its operating mines, cash flows from operations, effects of regulation and taxes by governmental agencies, mining technology improvements and reclamation costs. These assumptions are inherently subject to significant business, political, economic, regulatory, environmental and competitive uncertainties, pending and existing climate-related initiatives, contingencies and risks, all of which are difficult to predict and many of which are beyond the Company’s control. Therefore, the Company’s cash on hand and from future operations will be subject to any significant changes in these assumptions. COVID-19 Pandemic In the first quarter of 2020, the COVID-19 virus was declared a pandemic by the World Health Organization. The COVID-19 pandemic has had negative impacts on the Company’s business, results of operations, financial condition and cash flows. The full extent of the impact of the COVID-19 pandemic on the Company’s operational and financial performance will depend on certain developments, including the duration and spread of the outbreak, its impact on its customers and suppliers and the range of governmental and community reactions to the pandemic, which are still uncertain and still cannot be fully predicted. Recently Adopted Accounting Guidance Presentation of Financial Statements : In August 2021, the FASB issued ASU 2021-06 , Presentation of Financial Statements (Topic 205), Financial Services—Depository and Lending (Topic 942), and Financial Services—Investment Companies (Topic 946) (“ASU 2021-06”). This update amends certain SEC paragraphs from the Codification in response to the issuance of SEC Final Rule Nos. 33-10786, Amendments to Financial Disclosures About Acquired and Disposed Businesses, and 33-10835, Update of Statistical Disclosures for Bank and Savings and Loan Registrants. For all entities, the update is effective immediately. The Company adopted ASU 2021-06 during the third quarter of 2021. The adoption of this ASU did not have a material impact on the Company's Condensed Consolidated Financial Statements and related disclosures. Leases : In July 2021, the FASB issued ASU 2021-05, Leases (Topic 842) Lessors—Certain Leases with Variable Lease Payments (“ASU 2021-05”). The amendments in this update affect lessors with lease contracts that (1) have variable lease payments that do not depend on a reference index or a rate (“variable payments”) and (2) would have resulted in the recognition of a selling loss at lease commencement if classified as sales-type or direct financing. The amendments in this update address stakeholders’ concerns by amending the lease classification requirements for lessors to align them with practice under Topic 840 by requiring a lessor to classify a lease with variable payments as an operating lease on the commencement date of the lease if specified criteria are met. The amendments are effective for fiscal years beginning after December 15, 2021, for all entities, and interim periods within those fiscal years for public business entities with early application permitted. The Company adopted ASU 2021-05 during the third quarter of 2021. The adoption of this ASU did not have a material impact on the Company's Condensed Consolidated Financial Statements and related disclosures. Certain Modifications or Exchanges of Freestanding Equity-Classified Written Call Options: In May 2021, the FASB issued ASU 2021-04, Earnings Per Share (Topic 260), Debt—Modifications and Extinguishments (Subtopic 470-50), Compensation—Stock Compensation (Topic 718), and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40) (“ASU 2021-04”). The amendments in this update provide final guidance that requires issuers to account for modifications or exchanges of freestanding equity-classified written call options, such as the Company’s outstanding Series A warrants, that remain equity classified after the modification or exchange based on the economic substance of the modification or exchange. This ASU addresses the diversity in practice in issuers’ accounting by providing a principles-based framework to determine whether an issuer should recognize the modification or exchange as 1) an adjustment to equity and, if so, the related earnings per share effects, if any, or 2) an expense and, if so, the manner and pattern of recognition. For all entities, the standard is effective for fiscal years beginning after December 15, 2021, with early adoption permitted. The Company adopted ASU 2021-04 during the second quarter of 2021. The adoption of this ASU did not have a material impact on the Company's Condensed Consolidated Financial Statements and related disclosures. Reference Rate Reform : In January 2021, the FASB issued ASU 2021-01, Reference Rate Reform (Topic 848) (“ASU 2021-01”). The amendments in this update clarify that certain optional expedients and exceptions in Topic 848 for contract modifications and hedge accounting apply to derivatives that are affected by the discounting transition. For all entities, the standard is effective immediately. The Company adopted ASU 2021-01 during the first quarter of 2021. The adoption of this ASU did not have a material impact on the Company's Condensed Consolidated Financial Statements and related disclosures. Convertible Debt and Contracts in Entity’s Own Equity : In August 2020, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40)

Discontinued Operations

Discontinued Operations	9 Months Ended
	Sep. 30, 2021
Discontinued Operations and Disposal Groups [Abstract]
Discontinued Operations	Discontinued Operations Discontinued operations consist of activity related to the Company’s former NAPP operations. On December 10, 2020, the Company closed on a transaction to sell its thermal coal mining operations located in Pennsylvania consisting primarily of its Cumberland mining complex and related property to a third party purchaser, Iron Senergy Holdings, LLC (“Iron Senergy”). The mining permits associated with the Cumberland operations were obtained by Iron Senergy at closing. During the second quarter of 2021, nearly all of the Company’s remaining surety bonds were released and Iron Senergy’s replacement bonds were accepted through the administrative process with only $30 remaining as of September 30, 2021, which are expected to be released in the short-term. Major Financial Statement Components of Discontinued Operations The loss from discontinued operations before income taxes for the three and nine months ended September 30, 2021 was $429 and $1,067, respectively. The major components of loss from discontinued operations before income taxes in the Condensed Consolidated Statements of Operations for the three and nine months ended September 30, 2020 are as follows: Three Months Ended September 30, 2020 Nine Months Ended September 30, 2020 (1) Revenues: Total revenues $ 65,100 $ 190,654 Costs and expenses: Cost of coal sales (exclusive of items shown separately below) 57,398 167,663 Depreciation, depletion and amortization 1,503 10,545 Accretion on asset retirement obligations 2,390 3,861 Selling, general and administrative expenses (2) 186 1,573 Asset impairment and restructuring (3) 3,797 167,472 Other non-major income items, net (25) (134) Loss from discontinued operations before income taxes $ (149) $ (160,326) (1) Includes minor residual activity related to the Company’s former Powder River Basin (“PRB”) operations. (2) Represents professional and legal fees. (3) Refer to Note 7 for additional information on asset impairment and restructuring during the periods. Refer to the Condensed Consolidated Statements of Operations and Note 5 for loss per share information related to discontinued operations. The major components of assets and liabilities that are classified as discontinued operations in the Condensed Consolidated Balance Sheets are as follows: September 30, 2021 December 31, 2020 Assets: Trade accounts receivable, net of allowance for doubtful accounts $ — $ 7,504 Prepaid expenses and other current assets $ 1,391 $ 3,431 Other non-current assets (1) $ 9,477 $ 9,473 Liabilities: Trade accounts payable, accrued expenses and other current liabilities $ 7,095 $ 12,306 Workers’ compensation and black lung obligations, non-current $ 25,449 $ 27,799 Other non-current liabilities $ 1,291 $ 1,291 (1) Primarily comprised of workers’ compensation insurance receivable and long-term restricted investments collateralizing workers’ compensation obligations. The major components of cash flows related to discontinued operations are as follows: Nine Months Ended September 30, 2020 Depreciation, depletion and amortization $ 10,545 Capital expenditures $ 28,468 Other significant operating non-cash items related to discontinued operations: Accretion on asset retirement obligations $ 3,861 Asset impairment and restructuring $ 167,472

Revenue

Revenue	9 Months Ended
	Sep. 30, 2021
Revenue from Contract with Customer [Abstract]
Revenue	Revenue Disaggregation of Revenue from Contracts with Customers The Company earns revenues primarily through the sale of coal produced at Company operations and coal purchased from third parties. The Company extracts, processes and markets met and thermal coal from deep and surface mines for sale to steel and coke producers, industrial customers, and electric utilities. The Company has disaggregated revenue between met coal and thermal coal and export and domestic revenues which depicts the pricing and contract differences between the two. Export revenue generally is derived by spot or short term contracts with pricing determined at the time of shipment or based on a market index; whereas domestic revenue is characterized by contracts that typically have a term of one year or longer and typically the pricing is fixed. The following tables disaggregate the Company’s coal revenues by product category and by market to depict how the nature, amount, timing, and uncertainty of the Company’s coal revenues and cash flows are affected by economic factors: Three Months Ended September 30, 2021 Met Coal Thermal Coal Total Export coal revenues $ 503,566 $ 13,311 $ 516,877 Domestic coal revenues 92,115 38,137 130,252 Total coal revenues $ 595,681 $ 51,448 $ 647,129 Three Months Ended September 30, 2020 Met Coal Thermal Coal Total Export coal revenues $ 198,869 $ 6,707 $ 205,576 Domestic coal revenues 84,675 44,938 129,613 Total coal revenues $ 283,544 $ 51,645 $ 335,189 Nine Months Ended September 30, 2021 Met Thermal Total Export coal revenues $ 996,642 $ 20,035 $ 1,016,677 Domestic coal revenues 297,592 111,770 409,362 Total coal revenues $ 1,294,234 $ 131,805 $ 1,426,039 Nine Months Ended September 30, 2020 Met Thermal Total Export coal revenues $ 673,233 $ 24,459 $ 697,692 Domestic coal revenues 282,266 109,806 392,072 Total coal revenues $ 955,499 $ 134,265 $ 1,089,764 Performance Obligations The following table includes estimated revenue expected to be recognized in the future related to performance obligations that are unsatisfied as of September 30, 2021: Remainder of 2021 2022 2023 2024 2025 Total Estimated coal revenues $ 35,932 $ 53,500 $ 10,413 $ — $ — $ 99,845

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	9 Months Ended
	Sep. 30, 2021
Equity [Abstract]
Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Loss The following tables summarize the changes to accumulated other comprehensive loss during the nine months ended September 30, 2021 and 2020: Balance January 1, 2021 Other comprehensive income before reclassifications Amounts reclassified from accumulated other comprehensive loss Balance September 30, 2021 Employee benefit costs $ (111,985) $ 8,838 $ 4,239 $ (98,908) Balance January 1, 2020 Other comprehensive loss before reclassifications Amounts reclassified from accumulated other comprehensive loss Balance September 30, 2020 Employee benefit costs $ (58,616) $ (14,154) $ 4,156 $ (68,614) The following table summarizes the amounts reclassified from accumulated other comprehensive loss and the Condensed Consolidated Statements of Operations line items affected by the reclassification during the three and nine months ended September 30, 2021 and 2020: Details about accumulated other comprehensive loss components Amounts reclassified from accumulated other comprehensive loss Affected line item in the Condensed Consolidated Statements of Operations Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Employee benefit costs: Amortization of net actuarial loss (1) $ 1,413 $ 1,101 $ 4,239 $ 2,829 Miscellaneous income (loss), net Settlement (1) — 32 — 1,327 Miscellaneous income (loss), net Total before income tax $ 1,413 $ 1,133 $ 4,239 $ 4,156 Income tax — — — — Income tax (expense) benefit Total, net of income tax $ 1,413 $ 1,133 $ 4,239 $ 4,156 (1) These accumulated other comprehensive loss components are included in the computation of net periodic benefit costs for certain employee benefit plans. Refer to Note 14.

Net Income (Loss) Per Share

Net Income (Loss) Per Share	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Net Income (Loss) Per Share	Net Income (Loss) Per Share The number of shares used to calculate basic net income (loss) per common share is based on the weighted average number of the Company’s outstanding common shares during the respective period. The number of shares used to calculate diluted net income (loss) per common share is based on the number of common shares used to calculate basic net income (loss) per common share plus the dilutive effect of stock options and other stock-based instruments held by the Company’s employees and directors during the period, and the Company’s outstanding Series A warrants. The dilutive effect of outstanding stock-based instruments is determined by application of the treasury stock method. The warrants become dilutive for diluted net income (loss) per common share calculations when the market price of the Company’s common stock exceeds the exercise price. As discussed below, dilutive securities are not included in the computation of diluted net loss per common share for the three and nine months ended September 30, 2020 as the impact would be anti-dilutive. For the three months ended September 30, 2021 and 2020, 942,408 and 1,243,866 warrants, stock options, and other stock-based instruments, respectively, were excluded from the computation of dilutive net income (loss) per common share because they would have been anti-dilutive. For the nine months ended September 30, 2021 and 2020, 948,351 and 1,380,076 warrants, stock options, and other stock-based instruments, respectively, were excluded from the computation of dilutive net income (loss) per common share because they would have been anti-dilutive. When applying the treasury stock method, anti-dilution generally occurs when the exercise prices or unrecognized compensation cost per share are higher than the Company’s average stock price during an applicable period. Anti-dilution also occurs in periods of a net loss, and the dilutive impact of all share-based compensation awards are excluded. For the three months ended September 30, 2020 the weighted average share impact of other stock-based instruments that were excluded from the calculation of diluted shares due to the Company incurring a net loss for the period was 31,665. For the nine months ended September 30, 2020, the weighted average share impact of stock options and other stock-based instruments that were excluded from the calculation of diluted shares due to the Company incurring a net loss for the period was 38,648. The following table presents the net income (loss) per common share for the three and nine months ended September 30, 2021 and 2020: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Net income (loss) Income (loss) from continuing operations $ 83,693 $ (68,488) $ 32,412 $ (186,420) Loss from discontinued operations (429) (149) (1,067) (160,326) Net income (loss) $ 83,264 $ (68,637) $ 31,345 $ (346,746) Basic Weighted average common shares outstanding - basic 18,445,709 18,319,947 18,426,639 18,290,346 Basic income (loss) per common share: Income (loss) from continuing operations $ 4.54 $ (3.74) $ 1.76 $ (10.19) Loss from discontinued operations (0.03) (0.01) (0.06) (8.77) Net income (loss) $ 4.51 $ (3.75) $ 1.70 $ (18.96) Diluted Weighted average common shares outstanding - basic 18,445,709 18,319,947 18,426,639 18,290,346 Diluted effect of stock options 1,938 — 1,654 — Diluted effect of other stock-based instruments 465,705 — 355,350 — Weighted average common shares outstanding - diluted 18,913,352 18,319,947 18,783,643 18,290,346 Diluted income (loss) per common share: Income (loss) from continuing operations $ 4.43 $ (3.74) $ 1.73 $ (10.19) Loss from discontinued operations (0.03) (0.01) (0.06) (8.77) Net income (loss) $ 4.40 $ (3.75) $ 1.67 $ (18.96)

Inventories, net

Inventories, net	9 Months Ended
	Sep. 30, 2021
Inventory Disclosure [Abstract]
Inventories, net	Inventories, net Inventories, net consisted of the following: September 30, 2021 December 31, 2020 Raw coal $ 21,025 $ 15,084 Saleable coal 74,948 69,262 Materials, supplies and other, net 28,561 23,705 Total inventories, net $ 124,534 $ 108,051

Asset Impairment and Restructur

Asset Impairment and Restructuring	9 Months Ended
	Sep. 30, 2021
Restructuring and Related Activities [Abstract]
Asset Impairment and Restructuring	Asset Impairment and Restructuring Long-lived Asset Impairment During the nine months ended September 30, 2021, long-lived asset impairment of $60 was recorded in the All Other category to reduce the carrying value of property, plant, and equipment, net, due to capital spending during the period at previously impaired locations requiring the impairment of certain additional assets not considered recoverable. In connection with the preparation of the Company’s financial statements for the quarter ended September 30, 2020, the Company determined forecasted margins at certain locations continued to fall below amounts necessary for full recoverability and therefore indicators of impairment were present for three long-lived asset groups within its Met reporting segment and four long-lived asset groups within its All Other reporting segment. The Company therefore performed impairment testing on these assets and determined that, as of August 31, 2020, the carrying amounts of the asset groups exceeded both their undiscounted cash flows and their estimated fair values. The Company estimated the fair value of these asset groups generally using a discounted cash flow analysis utilizing market-participant assumptions. During the second quarter of 2020, as a result of the weakening coal market conditions due in part to the impact of the global COVID-19 pandemic, the Company announced that it would take certain strategic actions with respect to two of its thermal coal mining complexes in an effort to strengthen its financial performance and improve forecasted liquidity. The Company announced that an underground mine and preparation plant located in West Virginia would be idled during the third quarter of 2020. In addition, the Company decided not to move forward with the construction of a new refuse impoundment at its Cumberland mine in Pennsylvania and would therefore no longer spend the significant capital required in connection with the project. As a result, the Cumberland mine was expected to cease production by the end of 2022. On December 10, 2020, the Company sold its Cumberland mining operations. Refer to Note 2 for further details. In connection with the preparation of the Company’s financial statements for the quarter ended June 30, 2020, the Company determined that the strategic actions taken by the Company during the three months ended June 30, 2020, discussed above, shortened the lives of two mining complexes, and that continued weakening in metallurgical and thermal coal pricing had resulted in forecasted margins at certain locations falling below amounts necessary for full recoverability. As a result of these determinations, the Company assessed that indicators of impairment were present for three long-lived asset groups within its Met reporting segment and four long-lived asset groups within its All Other category. The Company therefore performed impairment testing on these assets and determined that, as of May 31, 2020, the carrying amounts of the asset groups exceeded both their undiscounted cash flows and their estimated fair values. The Company estimated the fair value of these asset groups generally using a discounted cash flow analysis utilizing market-participant assumptions. During the first quarter of 2020, due to declines in metallurgical and thermal coal pricing which reduced forecasted margins at certain locations to amounts below those required for full recoverability, the Company determined that indicators of impairment were present for four long-lived asset groups within its Met reporting segment and three long-lived asset groups within its All Other category and performed impairment testing as of February 29, 2020. At February 29, 2020, the Company determined that the carrying amounts of the asset groups exceeded both their undiscounted cash flows and their estimated fair values. The Company estimated the fair value of these asset groups generally using a discounted cash flow analysis utilizing market-participant assumptions. The following tables present the details of the long-lived asset impairment during the three and nine months ended September 30, 2020: Three Months Ended September 30, 2020 Nine Months Ended September 30, 2020 Continuing operations: Met $ — $ 32,951 All Other 219 18,367 Total from continuing operations $ 219 $ 51,318 Discontinued operations: $ 3,297 $ 147,645 Total long-lived asset impairment: $ 3,516 $ 198,963 Three Months Ended September 30, 2020 Nine Months Ended September 30, 2020 Continuing operations: Mineral rights, net $ — $ 24,066 Property, plant, and equipment, net 219 12,781 Acquired mine permits, net — 14,471 Total from continuing operations $ 219 $ 51,318 Discontinued operations: Mineral rights, net $ — $ 16,364 Property, plant, and equipment, net 3,297 131,281 Total from discontinued operations $ 3,297 $ 147,645 Total long-lived asset impairment: Mineral rights, net $ — $ 40,430 Property, plant, and equipment, net 3,516 144,062 Acquired mine permits, net — 14,471 Total long-lived asset impairment $ 3,516 $ 198,963 Restructuring As a result of the strategic actions announced in the second quarter of 2020 and subsequent changes to severance and employee-related benefits, the Company recorded restructuring expense of ($621) in the All Other category during the nine months ended September 30, 2021. As a result of the strategic actions discussed above, the Company recorded restructuring expense during the three and nine months ended September 30, 2020 as follows: Three Months Ended September 30, 2020 Total Restructuring Continuing Operations (2) Discontinued Operations Severance and employee-related benefits (1) $ 55 $ (445) $ 500 Total restructuring expense $ 55 $ (445) $ 500 Nine Months Ended September 30, 2020 Total Restructuring Continuing Operations (4) Discontinued Operations Severance and employee-related benefits (1) $ 20,608 $ 1,856 $ 18,752 Other costs (3) 1,882 807 1,075 Total restructuring expense $ 22,490 $ 2,663 $ 19,827 (1) Severance and employee-related benefits were considered probable and estimable based on provisions of contractual agreements and existing employee benefit plans. (2) Total restructuring expense from continuing operations of ($445) was recorded within the All Other category and affected Accrued expenses and other current liabilities. (3) Includes accelerated amortization of deferred longwall move expenses of $668, allowance for advanced mining royalties of $407, and allowance for obsolete materials and supplies inventory of $807. (4) Total restructuring expense from continuing operations of $2,663 was recorded within the All Other category and affected Accrued expenses and other current liabilities, Other non-current liabilities, and Inventories, net.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	9 Months Ended
	Sep. 30, 2021
Payables and Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consisted of the following: September 30, 2021 December 31, 2020 Wages and benefits $ 53,746 $ 40,330 Workers’ compensation 10,355 10,355 Black lung 6,784 6,784 Taxes other than income taxes 24,202 21,540 Current portion of asset retirement obligations 30,735 24,990 Accrued interest and fees 16,102 15,902 Deferred revenue 942 13,197 Freight accrual 13,231 2,610 Other 4,635 4,698 Total accrued expenses and other current liabilities $ 160,732 $ 140,406

Long-Term Debt

Long-Term Debt	9 Months Ended
	Sep. 30, 2021
Debt Disclosure [Abstract]
Long-Term Debt	Long-Term Debt Long-term debt consisted of the following: September 30, 2021 December 31, 2020 Term Loan Credit Facility - due June 2024 $ 499,435 $ 553,373 ABL Facility - due April 2022 — 3,350 LCC Note Payable 2,300 27,500 LCC Water Treatment Obligation 5,625 6,875 Other (1) 6,083 8,475 Debt discount and issuance costs (8,276) (17,046) Total long-term debt 505,167 582,527 Less current portion (7,976) (28,830) Long-term debt, net of current portion $ 497,191 $ 553,697 (1) Includes financing leases. Term Loan Credit Facility - due June 2024 As of September 30, 2021, the borrowings made under the senior secured term loan facility with a maturity date of June 14, 2024 (the “Term Loan Credit Facility”) were comprised of Eurocurrency Rate Loans (as defined therein) with an interest rate of 10.00%, calculated as the Eurocurrency rate during the period plus an applicable rate of 8.00%. As of September 30, 2021, the carrying value of the Term Loan Credit Facility was $492,092, all of which was classified as long-term within the Condensed Consolidated Balance Sheets. As of December 31, 2020, the carrying value of the Term Loan Credit Facility was $540,643, with $5,618 classified as current within the Condensed Consolidated Balance Sheets. During the three months ending September 30, 2021, the Company repurchased and permanently retired, through privately negotiated transactions, $18,724 of outstanding principal borrowings under the Term Loan Credit Facility. These borrowings were repurchased at a discount resulting in an aggregate purchase price of $18,415. As the participating lenders were existing shareholders (related parties) of the Company as of the repurchase date, the Company analyzed various factors regarding each of the transactions and concluded such repurchases were at a reasonable market rate and reflected the terms of an arm’s length transaction per the requirements of the Term Loan Credit Facility. Additionally, on September 30, 2021, the Company made a voluntary prepayment of $31,000 of outstanding principal borrowings under the Term Loan Credit Facility. As a result of the prepayment, no further amortization payments under the Term Loan Credit Facility are required prior to maturity. All obligations under the Term Loan Credit Facility are guaranteed by substantially all of Alpha’s direct and indirect subsidiaries. Certain obligations under the Term Loan Facility are secured by a senior lien, subject to certain exceptions (including the ABL Priority Collateral described below), by substantially all of Alpha’s assets and the assets of Alpha’s subsidiary guarantors (“Term Loan Priority Collateral”), in each case subject to exceptions. The obligations under the Term Loan Credit Facility are also secured by a junior lien, again subject to certain exceptions, against the ABL Priority Collateral. The Term Loan Facility contains negative and affirmative covenants including certain financial covenants that are more flexible than the covenants in the Amended and Restated Credit Agreement dated November 9, 2018. The Company was in compliance with all covenants under this agreement as of September 30, 2021. Amended and Restated Asset-Based Revolving Credit Agreement The Amended and Restated Asset-Based Revolving Credit Agreement includes a senior secured asset-based revolving credit facility (the “ABL Facility”). Under the ABL Facility, the Company may borrow cash or obtain letters of credit, on a revolving basis with any borrowings having a maturity date of April 3, 2022. As of September 30, 2021, the Company is in the process of refinancing the ABL Facility and expects that process to be completed prior to the maturity date. The Company anticipates a reduction in the size of the ABL Facility with borrowing capacity expected to be approximately $150,000 for the new facility. The Company expects the new facility to have sufficient availability to support the Company’s outstanding letters of credit under the current ABL Facility; however, there can be no assurance that the Company will be able to refinance the ABL Facility in a timely manner, or at all. As of September 30, 2021, there were no outstanding borrowings under the ABL Facility. As of December 31, 2020, the carrying value of the ABL Facility was $3,350, all of which was classified as long-term within the Condensed Consolidated Balance Sheets. As of September 30, 2021 and December 31, 2020, the Company had $120,037 and $123,108 letters of credit outstanding under the ABL Facility, respectively. The Amended and Restated Asset-Based Revolving Credit Agreement provides that a specified percentage of billed, unbilled and approved foreign receivables and raw and clean inventory meeting certain criteria are eligible to be counted for purposes of collateralizing the amount of financing available, subject to certain terms and conditions. Availability under the ABL Facility is calculated on a monthly basis and fluctuates based on qualifying amounts of coal inventory and trade accounts receivable (the “Borrowing Base”) and the facility's covenant limitations related to the Fixed Charge Coverage Ratio (as defined therein). In accordance with terms of the ABL Facility, the Company may be required to collateralize the ABL Facility to the extent outstanding borrowings and letters of credit under the ABL Facility exceed the Borrowing Base after considering covenant limitations. The ABL Facility is guaranteed by substantially all of Alpha’s direct and indirect subsidiaries (together with Alpha, the “Loan Parties”) and secured by all or substantially all assets of the Loan Parties, including equity in Alpha’s direct domestic subsidiaries and first-tier foreign subsidiaries, as collateral for the obligations under the ABL Facility. The ABL Facility has a first lien on ABL Priority Collateral (as defined therein) and a second lien on Term Loan Priority Collateral. The Amended and Restated Asset-Based Revolving Credit Agreement, as amended, and related documents contain negative and affirmative covenants including certain financial covenants. The Company is in compliance with all covenants under these agreements as of September 30, 2021. LCC Note Payable As a result of the Merger, the Company assumed a note payable to Lexington Coal Company (“LCC”) in the aggregate amount of $62,500 (the “LCC Note Payable”) and with a maturity date of July 26, 2022. The LCC Note Payable has no stated interest rate and an imputed interest rate of 12.45%. Principal repayments of $17,500 were due each July during 2019, 2020 and 2021, with the final principal payment of $10,000 due on the maturity date. On July 26, 2021, the Company prepaid $7,700 of the final principal payment. As a result of the prepayment, $13,982 of surety collateral was returned. As of September 30, 2021, the remaining $2,300 was expected to be paid in July of 2022. The carrying value of the LCC Note Payable was $2,066 and $24,423, with $2,066 and $17,500 reported within the current portion of long-term debt as of September 30, 2021 and December 31, 2020, respectively.

Acquisition-Related Obligations

Acquisition-Related Obligations	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Acquisition-Related Obligations	Acquisition-Related ObligationsAcquisition-related obligations consisted of the following: September 30, 2021 December 31, 2020 Contingent Revenue Obligation $ 35,580 $ 28,967 Environmental Settlement Obligations 8,139 10,391 UMWA Funds Settlement Liability 2,000 2,000 Discount (487) (1,491) Total acquisition-related obligations 45,232 39,867 Less current portion (26,266) (19,099) Acquisition-related obligations, net of current portion $ 18,966 $ 20,768 Contingent Revenue Obligation As of September 30, 2021 and December 31, 2020, the carrying value of the Contingent Revenue Obligation was $35,580 and $28,967, with $16,614 and $11,393 classified as current, respectively, classified as an acquisition-related obligation in the Condensed Consolidated Balance Sheets. Refer to Note 12 for further disclosures related to the fair value assignment and methods used. During the second quarter of 2021, the Company paid $11,396 pursuant to the terms of the Contingent Revenue Obligation.

Asset Retirement Obligations

Asset Retirement Obligations	9 Months Ended
	Sep. 30, 2021
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligations	Asset Retirement Obligations The following table summarizes the changes in asset retirement obligations for the nine months ended September 30, 2021: Total asset retirement obligations at December 31, 2020 $ 165,064 Accretion for the period 19,970 Sites added during the period 756 Revisions in estimated cash flows (500) Expenditures for the period (12,630) Total asset retirement obligations at September 30, 2021 172,660 Less current portion (1) (30,735) Long-term portion $ 141,925 (1) Included within accrued expenses and other current liabilities on the Company’s Condensed Consolidated Balance Sheets. Refer to Note 8.

Fair Value of Financial Instrum

Fair Value of Financial Instruments and Fair Value Measurements	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments and Fair Value Measurements	Fair Value of Financial Instruments and Fair Value Measurements The estimated fair values of financial instruments are determined based on relevant market information. These estimates involve uncertainty and cannot be determined with precision. The carrying amounts for cash and cash equivalents, trade accounts receivable, net, prepaid expenses and other current assets, short-term and long-term restricted cash, short-term and long-term deposits, trade accounts payable, and accrued expenses and other current liabilities approximate fair value as of September 30, 2021 and December 31, 2020 due to the short maturity of these instruments. The following tables set forth by level, within the fair value hierarchy, the Company’s long-term debt at fair value as of September 30, 2021 and December 31, 2020: September 30, 2021 Carrying Amount (1) Total Fair Value Quoted Prices in Active Markets Significant Other Observable Inputs Significant Unobservable Inputs Term Loan Credit Facility - due June 2024 $ 492,092 $ 494,753 $ — $ 494,753 $ — LCC Note Payable 2,066 2,054 — — 2,054 LCC Water Treatment Obligation 4,926 4,902 — — 4,902 Total long-term debt $ 499,084 $ 501,709 $ — $ 494,753 $ 6,956 December 31, 2020 Carrying Amount (1) Total Fair Value Quoted Prices in Active Markets Significant Other Observable Inputs Significant Unobservable Inputs Term Loan Credit Facility - due June 2024 $ 540,643 $ 379,614 $ — $ 379,614 $ — ABL Facility - due April 2022 3,350 3,057 — — 3,057 LCC Note Payable 24,423 20,328 — — 20,328 LCC Water Treatment Obligation 5,636 4,281 — — 4,281 Total long-term debt $ 574,052 $ 407,280 $ — $ 379,614 $ 27,666 (1) Net of debt discounts and debt issuance costs. The following tables set forth by level, within the fair value hierarchy, the Company’s acquisition-related obligations at fair value as of September 30, 2021 and December 31, 2020: September 30, 2021 Carrying Amount (1) Total Fair Value Quoted Prices in Active Markets Significant Other Observable Inputs Significant Unobservable Inputs UMWA Funds Settlement Liability $ 1,910 $ 1,934 $ — $ — $ 1,934 Environmental Settlement Obligations 7,742 7,723 — — 7,723 Total acquisition-related obligations $ 9,652 $ 9,657 $ — $ — $ 9,657 December 31, 2020 Carrying Amount (1) Total Fair Value Quoted Prices in Active Markets Significant Other Observable Inputs Significant Unobservable Inputs UMWA Funds Settlement Liability $ 1,662 $ 1,426 $ — $ — $ 1,426 Environmental Settlement Obligations 9,237 7,760 — — 7,760 Total acquisition-related obligations $ 10,899 $ 9,186 $ — $ — $ 9,186 (1) Net of discounts. The following table sets forth by level, within the fair value hierarchy, the Company’s financial and non-financial assets and liabilities that were accounted for at fair value on a recurring basis as of September 30, 2021 and December 31, 2020. Financial and non-financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company’s assessment of the significance of a particular input to the fair value measurement requires judgment, and may affect the determination of fair value for assets and liabilities and their placement within the fair value hierarchy levels. September 30, 2021 Total Fair Value Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Contingent Revenue Obligation $ 35,580 $ — $ — $ 35,580 Trading securities $ 28,695 $ 27,074 $ 1,621 $ — December 31, 2020 Total Fair Value Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Contingent Revenue Obligation $ 28,967 $ — $ — $ 28,967 Trading securities $ 22,498 $ 20,092 $ 2,406 $ — The following tables present a reconciliation of the financial and non-financial assets and liabilities that were accounted for at fair value on a recurring basis and that were categorized within Level 3 of the fair value hierarchy: December 31, 2020 Payments Loss (Gain) Recognized in Earnings (1) Transfer In (Out) of Level 3 Fair Value Hierarchy September 30, 2021 Contingent Revenue Obligation $ 28,967 $ (11,396) $ 18,009 $ — $ 35,580 (1) The loss recognized in earnings resulted primarily from an increase in forecasted future revenue as of September 30, 2021. December 31, 2019 Payments Loss (Gain) Recognized in Earnings (1) Transfer In (Out) of Level 3 Fair Value Hierarchy September 30, 2020 Contingent Revenue Obligation $ 52,427 $ (14,710) $ (13,425) $ — $ 24,292 (1) The gain recognized in earnings resulted primarily from a change in the forecasted future revenue associated with this obligation and an increase in annualized volatility as of September 30, 2020. The following methods and assumptions were used to estimate the fair values of the assets and liabilities in the tables above: Level 1 Fair Value Measurements Trading Securities - Includes money market funds and other cash equivalents. The fair value is based on observable market data. Level 2 Fair Value Measurements Term Loan Credit Facility - due June 2024 - The fair value is based on the average between bid and ask prices provided by a third-party. As the fair value is based on observable market inputs and due to limited trading volume in the Term Loan Credit Facility, the Company has classified the fair value within Level 2 of the fair value hierarchy. Trading Securities - Includes certificates of deposit, mutual funds, corporate debt securities and U.S. treasury and agency securities. The fair values of the Company’s trading securities are obtained from a third-party pricing service provider. The fair values provided by the pricing service provider are based on observable market inputs including credit spreads and broker-dealer quotes, among other inputs. The Company classifies the prices obtained from the pricing services within Level 2 of the fair value hierarchy because the underlying inputs are directly observable from active markets. However, the pricing models used entail a certain amount of subjectivity and therefore differing judgments in how the underlying inputs are modeled could result in different estimates of fair value. Level 3 Fair Value Measurements ABL Facility - due April 2022 - Observable transactions are not available to aid in determining the fair value of this item. Therefore, the fair value was derived by using the expected present value approach in which estimated cash flows are discounted using a risk-free interest rate adjusted for credit risk (discount rate of approximately 9% as of December 31, 2020). LCC Note Payable, LCC Water Treatment Obligation, UMWA Funds Settlement Liability and Environmental Settlement Obligations - Observable transactions are not available to aid in determining the fair value of these items. Therefore, the fair value was derived by using the expected present value approach in which estimated cash flows are discounted using a risk-free interest rate adjusted for credit risk (discount rates of approximately 14% and 34% as of September 30, 2021 and December 31, 2020, respectively). Contingent Revenue Obligation - The fair value of the contingent revenue obligation was estimated using a Black-Scholes pricing model and is marked to market at each reporting period with changes in value reflected in earnings. The inputs included in the Black-Scholes pricing model are the Company's forecasted future revenue, the stated royalty rate, the remaining periods in the obligation, annual risk-free interest rate based on the U.S. Constant Maturity Treasury Curve and annualized volatility. The annualized volatility was calculated by observing volatilities for comparable companies with adjustments for the Company's size and leverage. The range of significant unobservable inputs used to value the contingent revenue obligation as of September 30, 2021 and December 31, 2020, are set forth in the following table: September 30, 2021 December 31, 2020 Forecasted future revenue $1.4 - $2.0 billion $0.9 - $1.1 billion Stated royalty rate 1.0% - 1.5% 1.0% - 1.5% Annualized volatility 19.6% - 37.9% (34.2%) 19.4% - 52.1% (28.0%)

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes For the nine months ended September 30, 2021, the Company recorded income tax expense of $211 on income from continuing operations before income taxes of $32,623. The income tax expense differs from the expected statutory amount primarily due to the decrease in the valuation allowance and the permanent impact of percentage depletion deductions, partially offset by the impact of state income taxes, net of federal impact. As of September 30, 2021, the Company anticipates that no current federal income tax liability will be generated in 2021. For the nine months ended September 30, 2020, the Company recorded income tax benefit of $2,200 on a loss from continuing operations before income taxes of $188,620. The income tax benefit differs from the expected statutory amount primarily due to the increase in valuation allowance, partially offset by the permanent impact of percentage depletion deductions, the impact of state income taxes, net of federal tax impact, and the recording of a discrete tax benefit related to the refundability of previously sequestered AMT Credits. As a result of generating income before income taxes during the nine months ended September 30, 2021, the Company recorded a decrease of $12,701 to its deferred tax asset valuation allowance recorded as of September 30, 2021. The decrease in the valuation allowance results from a decrease in deferred tax assets since the prior reporting date of December 31, 2020. The valuation allowance associated with those deferred tax assets was released during the nine months ended September 30, 2021. The Company currently is relying primarily on the reversal of taxable temporary differences, along with consideration of taxable income via carryback to prior years and tax planning strategies, to support the realization of deferred tax assets. For each reporting period, the Company updates its assessment regarding the realizability of its deferred tax assets, including scheduling the reversal of its deferred tax assets and liabilities, to determine the amount of valuation allowance needed. Scheduling the reversal of deferred tax asset and liability balances requires judgment and estimation. The Company believes the deferred tax liabilities relied upon as future taxable income in its assessment will reverse in the same period and jurisdiction and are of the same character as the temporary differences giving rise to the deferred tax assets that will be realized. The valuation allowance recorded represents the portion of deferred tax assets for which the Company is unable to support realization through the methods described above. During the quarter ended September 30, 2021, the Internal Revenue Service (“IRS”) concluded its audit of the Company’s 2016 federal income tax return and associated net operating loss (“NOL”) carryback claim. The audit conclusion did not result in any material impact to the financial statements or related disclosures. Following the conclusion of the audit, the Company received the $64,160 carryback claim tax refund and $5,425 of accrued interest. The tax refund and accrued interest were

Employee Benefit Plans

Employee Benefit Plans	9 Months Ended
	Sep. 30, 2021
Compensation Related Costs [Abstract]
Employee Benefit Plans	Employee Benefit Plans The components of net periodic (benefit) expense other than the service cost component for the employee benefit plan obligations below are included in the line item miscellaneous income (loss), net in the Condensed Consolidated Statements of Operations. Pension The following table details the components of the net periodic benefit for pension obligations: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Interest cost $ 3,392 $ 4,670 $ 10,176 $ 14,061 Expected return on plan assets (7,183) (6,752) (21,549) (20,312) Amortization of net actuarial loss 804 511 2,413 1,501 Settlement — — — 1,230 Net periodic benefit $ (2,987) $ (1,571) $ (8,960) $ (3,520) During the three months ended June 30, 2021, an annual census data actuarial revaluation of pension obligations was performed, which resulted in a decrease in the liability for pension obligations of approximately $8,838 with the offset to accumulated other comprehensive gain and a slight increase in net periodic benefit to be recognized subsequent to the revaluation date. As a result of the recent funding relief granted under the American Rescue Plan Act, estimated contributions requirements to the pension plans were reduced relative to the Company’s previous estimates. The Company contributed $6,571 to the pension plans during the nine months ended September 30, 2021 and is not required to make additional contributions in the remainder of 2021. Black Lung The following table details the components of the net periodic expense for black lung obligations: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Service cost $ 739 $ 499 $ 2,217 $ 1,479 Interest cost 607 678 1,821 2,275 Expected return on plan assets (14) (13) (42) (40) Amortization of net actuarial loss 522 426 1,566 927 Net periodic expense $ 1,854 $ 1,590 $ 5,562 $ 4,641 Defined Contribution and Profit-Sharing Plans

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2021
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions During the three months ending September 30, 2021, the Company repurchased at a discount certain outstanding principal borrowings made under the Term Loan Credit Facility from existing shareholders through privately negotiated transactions. Refer to Note 9 for additional disclosures on long-term debt.There were no other material related party transactions for the nine months ended September 30, 2021 or 2020.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies (a) General Estimated losses from loss contingencies are accrued by a charge to income when information available indicates that it is probable that an asset has been impaired or a liability has been incurred and the amount of the loss can be reasonably estimated. If a loss contingency is not probable or reasonably estimable, disclosure of the loss contingency is made in the Condensed Consolidated Financial Statements when it is at least reasonably possible that a loss may be incurred and that the loss could be material. (b) Commitments and Contingencies Commitments The Company leases coal mining and other equipment under long-term financing and operating leases with varying terms. In addition, the Company leases mineral interests and surface rights from landowners under various terms and royalty rates. Other Commitments As of September 30, 2021, the Company has obligations under certain coal transportation agreements that contain minimum quantities to be shipped during contract periods from 2021 through 2022 with estimated obligations based on remaining tons to be shipped totaling $14,905 in 2022. The Company also has obligations under certain coal purchase agreements that contain minimum quantities to be purchased in the remainder of 2021 totaling an estimated $22,647, which includes an estimated $3,016 related to contractually committed fixed priced tons from vendors with historical performance resulting in less than 20% of the committed tonnage being delivered. Contingencies Extensive regulation of the impacts of mining on the environment and of maintaining workplace safety has had, and is expected to continue to have, a significant effect on the Company’s costs of production and results of operations. Further regulations, legislation or litigation in these areas may also cause the Company’s sales or profitability to decline by increasing costs or by hindering the Company’s ability to continue mining at existing operations or to permit new operations. During the normal course of business, contract-related matters arise between the Company and its customers. When a loss related to such matters is considered probable and can reasonably be estimated, the Company records a liability. As of September 30, 2021, per terms of the Cumberland Back-to-Back Coal Supply Agreements, the Company is required to purchase and sell 722 and 2,581 tons of coal in the remainder of 2021 and 2022 totaling $28,207 and $100,619, respectively. For the three and nine months ended September 30, 2021, the Company purchased and sold 514 and 1,974 tons, respectively, totaling $19,948 and $76,501, respectively, under the Cumberland Back-to-Back Coal Supply Agreements. Cumberland Back-to-Back Coal Supply Agreements are scheduled to be fully performed by December 31, 2022. (c) Guarantees and Financial Instruments with Off-Balance Sheet Risk In the normal course of business, the Company is a party to certain guarantees and 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 royalty obligations, are reflected in the Company’s Condensed Consolidated Balance Sheets. The Company is required to provide financial assurance in order to perform the post-mining reclamation required by its mining permits, pay workers’ compensation claims under workers’ compensation laws in various states, pay federal black lung benefits, and perform certain other obligations. In order to provide the required financial assurance, the Company generally uses surety bonds for post-mining reclamation and workers’ compensation obligations. The Company can also use bank letters of credit to collateralize certain obligations. As of September 30, 2021, the Company had $120,037 letters of credit outstanding under the Amended and Restated Asset-Based Revolving Credit Agreement. Additionally, as of September 30, 2021, the Company had $613 letters of credit outstanding under the Credit and Security Agreement dated June 30, 2017, and related amendments, between ANR, Inc. and First Tennessee Bank National Association. On March 31, 2021, the Amended and Restated Letter of Credit Agreement dated November 9, 2018 between ANR, Inc. and Citibank, N.A. was terminated. As of September 30, 2021, the Company had outstanding surety bonds with a total face amount of $176,909 to secure various obligations and commitments, including $30 attributable to discontinued operations. To secure the Company’s reclamation-related obligations, the Company has $37,164 of collateral supporting these obligations as of September 30, 2021. The Company meets frequently with its surety providers and has discussions with certain providers regarding the extent of and the terms of their participation in the program. These discussions may cause the Company to shift surety bonds between providers or to alter the terms of their participation in our program. To the extent that surety bonds become unavailable or the Company’s surety bond providers require additional collateral, the Company would seek to secure its obligations with letters of credit, cash deposits or other suitable forms of collateral. The Company’s failure to maintain, or inability to acquire, surety bonds or to provide a suitable alternative would have a material adverse effect on its liquidity. These failures could result from a variety of factors including lack of availability, higher cost or unfavorable market terms of new surety bonds, and the exercise by third-party surety bond issuers of their right to refuse to renew the surety. Amounts included in restricted cash represent cash deposits primarily invested in interest bearing accounts that are restricted as to withdrawal as required by certain agreements entered into by the Company and provide collateral to secure the following obligations which have been written on the Company’s behalf: September 30, 2021 December 31, 2020 Workers' compensation and black lung obligations $ 66,488 $ 69,725 Reclamation-related obligations 10,580 8,445 Financial payments and other performance obligations 6,933 17,863 Contingent revenue obligation escrow 7,642 9,311 Total restricted cash 91,643 105,344 Less current portion (1) (7,642) (9,311) Restricted cash, net of current portion $ 84,001 $ 96,033 (1) Included within prepaid expenses and other current assets on the Company’s Condensed Consolidated Balance Sheets. Restricted investments consist of Federal Deposit Insurance Company (“FDIC”) insured certificates of deposit, mutual funds, and U.S. treasury bills that are restricted as to withdrawal as required by certain agreements entered into by the Company and provide collateral to secure the following obligations which have been written on the Company’s behalf: September 30, 2021 December 31, 2020 Workers' compensation obligations $ 211 $ 51 Reclamation-related obligations 26,467 22,233 Financial payments and other performance obligations 2,017 1,484 Total restricted investments (1), (2) $ 28,695 $ 23,768 (1) Included within other non-current assets on the Company’s Condensed Consolidated Balance Sheets. (2) As of September 30, 2021 and December 31, 2020, respectively, $28,695 and $22,498 are classified as trading securities and $0 and $1,270 are classified as held-to-maturity securities. Deposits represent cash deposits held at third parties as required by certain agreements entered into by the Company to provide cash collateral to secure the following obligations which have been written on the Company’s behalf: September 30, 2021 December 31, 2020 Reclamation-related obligations $ 117 $ 25,633 Financial payments and other performance obligations 403 1,596 Other operating agreements 881 1,018 Total deposits (1) $ 1,401 $ 28,247 (1) Included within prepaid expenses and other current assets and other non-current assets on the Company’s Condensed Consolidated Balance Sheets. DCMWC Reauthorization Process In July 2019, the U.S. Department of Labor (Division of Coal Mine Workers’ Compensation or “DCMWC”) began implementing a new authorization process for all self-insured coal mine operators. As requested by the DCMWC, the Company filed an application and supporting documentation for reauthorization to self-insure certain of its black lung obligations in October 2019. As a result of this application, the DCMWC notified the Company in a letter dated February 21, 2020 that the Company was reauthorized to self-insure certain of its black lung obligations for a period of one-year from February 21, 2020. The DCMWC reauthorization is contingent, however, upon the Company’s providing collateral of $65,700 to secure certain of its black lung obligations. This proposed collateral requirement is an increase from the approximate $2,600 in collateral that the Company currently provides to secure these self-insured black lung obligations. The reauthorization process provided the Company with the right to appeal the security determination in writing within 30 days of the date of the notification, which appeal period the DCMWC agreed to extend to May 22, 2020. The Company exercised this right of appeal in connection with the substantial increase in the amount of required collateral. However, there has been no substantive activity under the appeal since its filing. In February 2021, the U.S. Department of Labor withdrew its Federal Register notice seeking comments on its bulletin describing its new method of calculating collateral requirements. The Department removed the bulletin from its website in May 2021. If the Company’s appeal is unsuccessful, the Company may be required to provide additional letters of credit to receive the self-insurance reauthorization from the DCMWC or alternatively insure these black lung obligations through a third party provider that would likely also require the Company to provide additional collateral. Either of these outcomes could potentially reduce the Company’s liquidity. (d) Legal Proceedings The Company is party to legal proceedings from time to time. These proceedings, as well as governmental examinations, could involve various business units and a variety of claims including, but not limited to, contract disputes, personal injury claims, property damage claims (including those resulting from blasting, trucking and flooding), environmental and safety issues, securities-related matters and employment matters. While some legal matters may specify the damages claimed by the plaintiffs, many seek an unquantified amount of damages. Even when the amount of damages claimed against the Company or its subsidiaries is stated, (i) the claimed amount may be exaggerated or unsupported; (ii) the claim may be based on a novel legal theory or involve a large number of parties; (iii) there may be uncertainty as to the likelihood of a class being certified or the ultimate size of the class; (iv) there may be uncertainty as to the outcome of pending appeals or motions; and/or (v) there may be significant factual issues to be resolved. As a result, if such legal matters arise in the future, the Company may be unable to estimate a range of possible loss for matters that have not yet progressed sufficiently through discovery and development of important factual information and legal issues. The Company records accruals based on an estimate of the ultimate outcome of these matters, but these estimates can be difficult to determine and involve significant judgment.

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 2021
Segment Reporting [Abstract]
Segment Information	Segment Information The Company extracts, processes and markets met and thermal coal from deep and surface mines for sale to steel and coke producers, industrial customers, and electric utilities. The Company conducts mining operations only in the United States with mines in Central Appalachia (“CAPP”). The Company has one reportable segment: Met, which consists of five active mines and two preparation plants in Virginia, thirteen active mines and five preparation plants in West Virginia, as well as expenses associated with certain idled/closed mines. Prior to the first quarter of 2021, the Company had two reportable segments: CAPP - Met and CAPP - Thermal. As a result of the Company’s continued strategic focus on the production of metallurgical coal and the reduction of thermal mining operations, the Company re-evaluated its previous conclusions with respect to its segment reporting during the first quarter of 2021. To conform to the current period reportable segments presentation, the prior periods have been restated to reflect the change in reportable segments. In addition to the one reportable segment, the All Other category includes general corporate overhead and corporate assets and liabilities, the former CAPP - Thermal operations consisting of one active mine and one preparation plant in West Virginia, and the elimination of certain intercompany activity, as well as expenses associated with certain idled/closed mines. Reportable segment operating results are regularly reviewed by the Chief Operating Decision Maker (“CODM”), who is the Chief Executive Officer of the Company. Segment operating results and capital expenditures for the three months ended September 30, 2021 and 2020 were as follows: Three Months Ended September 30, 2021 Met All Other Consolidated Total revenues $ 626,103 $ 22,738 $ 648,841 Depreciation, depletion, and amortization $ 23,181 $ 1,338 $ 24,519 Amortization of acquired intangibles, net $ 3,063 $ (83) $ 2,980 Adjusted EBITDA $ 155,456 $ (7,234) $ 148,222 Capital expenditures $ 21,882 $ 465 $ 22,347 Three Months Ended September 30, 2020 Met All Other Consolidated Total revenues $ 295,381 $ 40,211 $ 335,592 Depreciation, depletion, and amortization $ 41,178 $ 8,058 $ 49,236 Amortization of acquired intangibles, net $ 2,535 $ (461) $ 2,074 Adjusted EBITDA $ 17,772 $ (5,412) $ 12,360 Capital expenditures $ 22,668 $ 839 $ 23,507 Segment operating results and capital expenditures for the nine months ended September 30, 2021 and 2020 were as follows: Nine Months Ended September 30, 2021 Met All Other Consolidated Total revenues $ 1,363,918 $ 66,451 $ 1,430,369 Depreciation, depletion, and amortization $ 75,403 $ 4,858 $ 80,261 Amortization of acquired intangibles, net $ 9,749 $ (347) $ 9,402 Adjusted EBITDA $ 234,824 $ (17,801) $ 217,023 Capital expenditures $ 59,408 $ 978 $ 60,386 Nine Months Ended September 30, 2020 Met All Other Consolidated Total revenues $ 974,674 $ 117,662 $ 1,092,336 Depreciation, depletion, and amortization $ 121,679 $ 22,242 $ 143,921 Amortization of acquired intangibles, net $ 7,875 $ (3,409) $ 4,466 Adjusted EBITDA $ 104,408 $ (28,406) $ 76,002 Capital expenditures $ 83,449 $ 6,979 $ 90,428 The following tables present a reconciliation of net income (loss) to Adjusted EBITDA for the three months ended September 30, 2021 and 2020: Three Months Ended September 30, 2021 Met All Other Consolidated Net income (loss) from continuing operations $ 125,750 $ (42,057) $ 83,693 Interest expense 49 17,289 17,338 Interest income (1) (53) (54) Income tax expense — 208 208 Depreciation, depletion and amortization 23,181 1,338 24,519 Non-cash stock compensation expense 6 1,182 1,188 Mark-to-market adjustment - acquisition-related obligations — 11,676 11,676 Accretion on asset retirement obligations 3,408 3,266 6,674 Amortization of acquired intangibles, net 3,063 (83) 2,980 Adjusted EBITDA $ 155,456 $ (7,234) $ 148,222 Three Months Ended September 30, 2020 Met All Other Consolidated Net loss from continuing operations $ (29,656) $ (38,832) $ (68,488) Interest expense (188) 18,934 18,746 Interest income (2) (374) (376) Income tax benefit — (45) (45) Depreciation, depletion and amortization 41,178 8,058 49,236 Non-cash stock compensation expense 105 973 1,078 Mark-to-market adjustment - acquisition-related obligations — 3,624 3,624 Accretion on asset retirement obligations 3,800 2,937 6,737 Asset impairment and restructuring (1) — (226) (226) Amortization of acquired intangibles, net 2,535 (461) 2,074 Adjusted EBITDA $ 17,772 $ (5,412) $ 12,360 (1) Refer to Note 7 for additional information on asset impairment and restructuring during the period. The following tables present a reconciliation of net income (loss) to Adjusted EBITDA for the nine months ended September 30, 2021 and 2020: Nine Months Ended September 30, 2021 Met All Other Consolidated Net income (loss) from continuing operations $ 139,354 $ (106,942) $ 32,412 Interest expense 132 53,158 53,290 Interest income (6) (316) (322) Income tax expense — 211 211 Depreciation, depletion and amortization 75,403 4,858 80,261 Non-cash stock compensation expense 22 4,329 4,351 Mark-to-market adjustment - acquisition-related obligations — 18,009 18,009 Accretion on asset retirement obligations 10,170 9,800 19,970 Asset impairment and restructuring (1) — (561) (561) Amortization of acquired intangibles, net 9,749 (347) 9,402 Adjusted EBITDA $ 234,824 $ (17,801) $ 217,023 (1) Refer to Note 7 for additional information on asset impairment and restructuring during the period. Nine Months Ended September 30, 2020 Met All Other Consolidated Net loss from continuing operations $ (68,338) $ (118,082) $ (186,420) Interest expense (1,494) 57,732 56,238 Interest income (63) (6,811) (6,874) Income tax benefit — (2,200) (2,200) Depreciation, depletion and amortization 121,679 22,242 143,921 Non-cash stock compensation expense 410 3,790 4,200 Mark-to-market adjustment - acquisition-related obligations — (13,425) (13,425) Accretion on asset retirement obligations 10,887 9,058 19,945 Asset impairment and restructuring (1) 32,951 21,030 53,981 Management restructuring costs (2) 501 439 940 Loss on partial settlement of benefit obligations — 1,230 1,230 Amortization of acquired intangibles, net 7,875 (3,409) 4,466 Adjusted EBITDA $ 104,408 $ (28,406) $ 76,002 (1) Refer to Note 7 for additional information on asset impairment and restructuring during the period. (2) Management restructuring costs are related to severance expense associated with senior management changes in the three months ended March 31, 2020. No asset information has been disclosed as the CODM does not regularly review asset information by reportable segment. The Company markets produced, processed and purchased coal to customers in the United States and in international markets, primarily China, India, and Brazil. Revenue is tracked within the Company’s accounting records based on the product destination. Export coal revenues were the following: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Total coal revenues $ 647,129 $ 335,189 $ 1,426,039 $ 1,089,764 Export coal revenues $ 516,877 $ 205,576 $ 1,016,677 $ 697,692 Export coal revenues as % of total coal revenues 80 % 61 % 71 % 64 % Countries with export coal revenue exceeding 10% of total revenue China, India India China, India, Brazil India, Brazil

Business and Basis of Present_2

Business and Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation Together, the condensed consolidated statements of operations, comprehensive loss, balance sheets, cash flows and stockholders’ equity for the Company are referred to as the “Condensed Consolidated Financial Statements.” The Condensed Consolidated Financial Statements are also referenced across periods as “Condensed Consolidated Statements of Operations,” “Condensed Consolidated Statements of Comprehensive Loss,” “Condensed Consolidated Balance Sheets,” “Condensed Consolidated Statements of Cash Flows,” and “Condensed Consolidated Statements of Stockholders’ Equity.” The Company’s former Northern Appalachia (“NAPP”) operations results of operations and financial position are reported as discontinued operations in the Condensed Consolidated Financial Statements. The historical information in the accompanying Notes to the Condensed Consolidated Financial Statements has been restated to reflect the effects of the Company’s former NAPP operations being reported as discontinued operations in the Condensed Consolidated Financial Statements. Refer to Note 2 for further information on discontinued operations. The Condensed Consolidated Financial Statements include all wholly-owned subsidiaries’ results of operations for the three and nine months ended September 30, 2021 and 2020. All significant intercompany transactions have been eliminated in consolidation.
Reclassifications	ReclassificationsCertain amounts in the prior year Condensed Consolidated Statements of Cash Flows have been reclassified to conform to the current year presentation.
Liquidity Risk and Uncertainties	Liquidity Risks and UncertaintiesThe Company believes it will have sufficient liquidity to meet its working capital requirements, anticipated capital expenditures, debt service requirements, acquisition-related obligations, and reclamation obligations for the 12 months subsequent to the issuance of these financial statements. However, the Company may need to raise additional funds if market conditions deteriorate and may not be able to do so in a timely fashion, or at all. The Company relies on a number of assumptions in budgeting for future activities. These include the costs for mine development to sustain capacity of its operating mines, cash flows from operations, effects of regulation and taxes by governmental agencies, mining technology improvements and reclamation costs. These assumptions are inherently subject to significant business, political, economic, regulatory, environmental and competitive uncertainties, pending and existing climate-related initiatives, contingencies and risks, all of which are difficult to predict and many of which are beyond the Company’s control. Therefore, the Company’s cash on hand and from future operations will be subject to any significant changes in these assumptions.
Recently Adopted Accounting Guidance	Recently Adopted Accounting Guidance Presentation of Financial Statements : In August 2021, the FASB issued ASU 2021-06 , Presentation of Financial Statements (Topic 205), Financial Services—Depository and Lending (Topic 942), and Financial Services—Investment Companies (Topic 946) (“ASU 2021-06”). This update amends certain SEC paragraphs from the Codification in response to the issuance of SEC Final Rule Nos. 33-10786, Amendments to Financial Disclosures About Acquired and Disposed Businesses, and 33-10835, Update of Statistical Disclosures for Bank and Savings and Loan Registrants. For all entities, the update is effective immediately. The Company adopted ASU 2021-06 during the third quarter of 2021. The adoption of this ASU did not have a material impact on the Company's Condensed Consolidated Financial Statements and related disclosures. Leases : In July 2021, the FASB issued ASU 2021-05, Leases (Topic 842) Lessors—Certain Leases with Variable Lease Payments (“ASU 2021-05”). The amendments in this update affect lessors with lease contracts that (1) have variable lease payments that do not depend on a reference index or a rate (“variable payments”) and (2) would have resulted in the recognition of a selling loss at lease commencement if classified as sales-type or direct financing. The amendments in this update address stakeholders’ concerns by amending the lease classification requirements for lessors to align them with practice under Topic 840 by requiring a lessor to classify a lease with variable payments as an operating lease on the commencement date of the lease if specified criteria are met. The amendments are effective for fiscal years beginning after December 15, 2021, for all entities, and interim periods within those fiscal years for public business entities with early application permitted. The Company adopted ASU 2021-05 during the third quarter of 2021. The adoption of this ASU did not have a material impact on the Company's Condensed Consolidated Financial Statements and related disclosures. Certain Modifications or Exchanges of Freestanding Equity-Classified Written Call Options: In May 2021, the FASB issued ASU 2021-04, Earnings Per Share (Topic 260), Debt—Modifications and Extinguishments (Subtopic 470-50), Compensation—Stock Compensation (Topic 718), and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40) (“ASU 2021-04”). The amendments in this update provide final guidance that requires issuers to account for modifications or exchanges of freestanding equity-classified written call options, such as the Company’s outstanding Series A warrants, that remain equity classified after the modification or exchange based on the economic substance of the modification or exchange. This ASU addresses the diversity in practice in issuers’ accounting by providing a principles-based framework to determine whether an issuer should recognize the modification or exchange as 1) an adjustment to equity and, if so, the related earnings per share effects, if any, or 2) an expense and, if so, the manner and pattern of recognition. For all entities, the standard is effective for fiscal years beginning after December 15, 2021, with early adoption permitted. The Company adopted ASU 2021-04 during the second quarter of 2021. The adoption of this ASU did not have a material impact on the Company's Condensed Consolidated Financial Statements and related disclosures. Reference Rate Reform : In January 2021, the FASB issued ASU 2021-01, Reference Rate Reform (Topic 848) (“ASU 2021-01”). The amendments in this update clarify that certain optional expedients and exceptions in Topic 848 for contract modifications and hedge accounting apply to derivatives that are affected by the discounting transition. For all entities, the standard is effective immediately. The Company adopted ASU 2021-01 during the first quarter of 2021. The adoption of this ASU did not have a material impact on the Company's Condensed Consolidated Financial Statements and related disclosures. Convertible Debt and Contracts in Entity’s Own Equity : In August 2020, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40)

Discontinued Operations (Tables

Discontinued Operations (Tables)	9 Months Ended
	Sep. 30, 2021
Discontinued Operations and Disposal Groups [Abstract]
Discontinued Operations	The major components of loss from discontinued operations before income taxes in the Condensed Consolidated Statements of Operations for the three and nine months ended September 30, 2020 are as follows: Three Months Ended September 30, 2020 Nine Months Ended September 30, 2020 (1) Revenues: Total revenues $ 65,100 $ 190,654 Costs and expenses: Cost of coal sales (exclusive of items shown separately below) 57,398 167,663 Depreciation, depletion and amortization 1,503 10,545 Accretion on asset retirement obligations 2,390 3,861 Selling, general and administrative expenses (2) 186 1,573 Asset impairment and restructuring (3) 3,797 167,472 Other non-major income items, net (25) (134) Loss from discontinued operations before income taxes $ (149) $ (160,326) (1) Includes minor residual activity related to the Company’s former Powder River Basin (“PRB”) operations. (2) Represents professional and legal fees. (3) Refer to Note 7 for additional information on asset impairment and restructuring during the periods. The major components of assets and liabilities that are classified as discontinued operations in the Condensed Consolidated Balance Sheets are as follows: September 30, 2021 December 31, 2020 Assets: Trade accounts receivable, net of allowance for doubtful accounts $ — $ 7,504 Prepaid expenses and other current assets $ 1,391 $ 3,431 Other non-current assets (1) $ 9,477 $ 9,473 Liabilities: Trade accounts payable, accrued expenses and other current liabilities $ 7,095 $ 12,306 Workers’ compensation and black lung obligations, non-current $ 25,449 $ 27,799 Other non-current liabilities $ 1,291 $ 1,291 (1) Primarily comprised of workers’ compensation insurance receivable and long-term restricted investments collateralizing workers’ compensation obligations. The major components of cash flows related to discontinued operations are as follows: Nine Months Ended September 30, 2020 Depreciation, depletion and amortization $ 10,545 Capital expenditures $ 28,468 Other significant operating non-cash items related to discontinued operations: Accretion on asset retirement obligations $ 3,861 Asset impairment and restructuring $ 167,472

Revenue (Tables)

Revenue (Tables)	9 Months Ended
	Sep. 30, 2021
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following tables disaggregate the Company’s coal revenues by product category and by market to depict how the nature, amount, timing, and uncertainty of the Company’s coal revenues and cash flows are affected by economic factors: Three Months Ended September 30, 2021 Met Coal Thermal Coal Total Export coal revenues $ 503,566 $ 13,311 $ 516,877 Domestic coal revenues 92,115 38,137 130,252 Total coal revenues $ 595,681 $ 51,448 $ 647,129 Three Months Ended September 30, 2020 Met Coal Thermal Coal Total Export coal revenues $ 198,869 $ 6,707 $ 205,576 Domestic coal revenues 84,675 44,938 129,613 Total coal revenues $ 283,544 $ 51,645 $ 335,189 Nine Months Ended September 30, 2021 Met Thermal Total Export coal revenues $ 996,642 $ 20,035 $ 1,016,677 Domestic coal revenues 297,592 111,770 409,362 Total coal revenues $ 1,294,234 $ 131,805 $ 1,426,039 Nine Months Ended September 30, 2020 Met Thermal Total Export coal revenues $ 673,233 $ 24,459 $ 697,692 Domestic coal revenues 282,266 109,806 392,072 Total coal revenues $ 955,499 $ 134,265 $ 1,089,764
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction	The following table includes estimated revenue expected to be recognized in the future related to performance obligations that are unsatisfied as of September 30, 2021: Remainder of 2021 2022 2023 2024 2025 Total Estimated coal revenues $ 35,932 $ 53,500 $ 10,413 $ — $ — $ 99,845

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Loss (Tables)	9 Months Ended
	Sep. 30, 2021
Equity [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	The following tables summarize the changes to accumulated other comprehensive loss during the nine months ended September 30, 2021 and 2020: Balance January 1, 2021 Other comprehensive income before reclassifications Amounts reclassified from accumulated other comprehensive loss Balance September 30, 2021 Employee benefit costs $ (111,985) $ 8,838 $ 4,239 $ (98,908) Balance January 1, 2020 Other comprehensive loss before reclassifications Amounts reclassified from accumulated other comprehensive loss Balance September 30, 2020 Employee benefit costs $ (58,616) $ (14,154) $ 4,156 $ (68,614) The following table summarizes the amounts reclassified from accumulated other comprehensive loss and the Condensed Consolidated Statements of Operations line items affected by the reclassification during the three and nine months ended September 30, 2021 and 2020: Details about accumulated other comprehensive loss components Amounts reclassified from accumulated other comprehensive loss Affected line item in the Condensed Consolidated Statements of Operations Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Employee benefit costs: Amortization of net actuarial loss (1) $ 1,413 $ 1,101 $ 4,239 $ 2,829 Miscellaneous income (loss), net Settlement (1) — 32 — 1,327 Miscellaneous income (loss), net Total before income tax $ 1,413 $ 1,133 $ 4,239 $ 4,156 Income tax — — — — Income tax (expense) benefit Total, net of income tax $ 1,413 $ 1,133 $ 4,239 $ 4,156 (1) These accumulated other comprehensive loss components are included in the computation of net periodic benefit costs for certain employee benefit plans. Refer to Note 14.

Net Income (Loss) Per Share (Ta

Net Income (Loss) Per Share (Tables)	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Schedule of Net (Loss) Income Per Common Share, Basic and Diluted	The following table presents the net income (loss) per common share for the three and nine months ended September 30, 2021 and 2020: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Net income (loss) Income (loss) from continuing operations $ 83,693 $ (68,488) $ 32,412 $ (186,420) Loss from discontinued operations (429) (149) (1,067) (160,326) Net income (loss) $ 83,264 $ (68,637) $ 31,345 $ (346,746) Basic Weighted average common shares outstanding - basic 18,445,709 18,319,947 18,426,639 18,290,346 Basic income (loss) per common share: Income (loss) from continuing operations $ 4.54 $ (3.74) $ 1.76 $ (10.19) Loss from discontinued operations (0.03) (0.01) (0.06) (8.77) Net income (loss) $ 4.51 $ (3.75) $ 1.70 $ (18.96) Diluted Weighted average common shares outstanding - basic 18,445,709 18,319,947 18,426,639 18,290,346 Diluted effect of stock options 1,938 — 1,654 — Diluted effect of other stock-based instruments 465,705 — 355,350 — Weighted average common shares outstanding - diluted 18,913,352 18,319,947 18,783,643 18,290,346 Diluted income (loss) per common share: Income (loss) from continuing operations $ 4.43 $ (3.74) $ 1.73 $ (10.19) Loss from discontinued operations (0.03) (0.01) (0.06) (8.77) Net income (loss) $ 4.40 $ (3.75) $ 1.67 $ (18.96)

Inventories, net (Tables)

Inventories, net (Tables)	9 Months Ended
	Sep. 30, 2021
Inventory Disclosure [Abstract]
Schedule of Inventory	Inventories, net consisted of the following: September 30, 2021 December 31, 2020 Raw coal $ 21,025 $ 15,084 Saleable coal 74,948 69,262 Materials, supplies and other, net 28,561 23,705 Total inventories, net $ 124,534 $ 108,051

Asset Impairment and Restruct_2

Asset Impairment and Restructuring (Tables)	9 Months Ended
	Sep. 30, 2021
Restructuring and Related Activities [Abstract]
Details of Impairment of Long-Lived Assets Held and Used by Asset	The following tables present the details of the long-lived asset impairment during the three and nine months ended September 30, 2020: Three Months Ended September 30, 2020 Nine Months Ended September 30, 2020 Continuing operations: Met $ — $ 32,951 All Other 219 18,367 Total from continuing operations $ 219 $ 51,318 Discontinued operations: $ 3,297 $ 147,645 Total long-lived asset impairment: $ 3,516 $ 198,963 Three Months Ended September 30, 2020 Nine Months Ended September 30, 2020 Continuing operations: Mineral rights, net $ — $ 24,066 Property, plant, and equipment, net 219 12,781 Acquired mine permits, net — 14,471 Total from continuing operations $ 219 $ 51,318 Discontinued operations: Mineral rights, net $ — $ 16,364 Property, plant, and equipment, net 3,297 131,281 Total from discontinued operations $ 3,297 $ 147,645 Total long-lived asset impairment: Mineral rights, net $ — $ 40,430 Property, plant, and equipment, net 3,516 144,062 Acquired mine permits, net — 14,471 Total long-lived asset impairment $ 3,516 $ 198,963
Schedule of Restructuring Expense	As a result of the strategic actions discussed above, the Company recorded restructuring expense during the three and nine months ended September 30, 2020 as follows: Three Months Ended September 30, 2020 Total Restructuring Continuing Operations (2) Discontinued Operations Severance and employee-related benefits (1) $ 55 $ (445) $ 500 Total restructuring expense $ 55 $ (445) $ 500 Nine Months Ended September 30, 2020 Total Restructuring Continuing Operations (4) Discontinued Operations Severance and employee-related benefits (1) $ 20,608 $ 1,856 $ 18,752 Other costs (3) 1,882 807 1,075 Total restructuring expense $ 22,490 $ 2,663 $ 19,827 (1) Severance and employee-related benefits were considered probable and estimable based on provisions of contractual agreements and existing employee benefit plans. (2) Total restructuring expense from continuing operations of ($445) was recorded within the All Other category and affected Accrued expenses and other current liabilities. (3) Includes accelerated amortization of deferred longwall move expenses of $668, allowance for advanced mining royalties of $407, and allowance for obsolete materials and supplies inventory of $807. (4) Total restructuring expense from continuing operations of $2,663 was recorded within the All Other category and affected Accrued expenses and other current liabilities, Other non-current liabilities, and Inventories, net.

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	9 Months Ended
	Sep. 30, 2021
Payables and Accruals [Abstract]
Schedule of Accounts Payable and Accrued Liabilities	Accrued expenses and other current liabilities consisted of the following: September 30, 2021 December 31, 2020 Wages and benefits $ 53,746 $ 40,330 Workers’ compensation 10,355 10,355 Black lung 6,784 6,784 Taxes other than income taxes 24,202 21,540 Current portion of asset retirement obligations 30,735 24,990 Accrued interest and fees 16,102 15,902 Deferred revenue 942 13,197 Freight accrual 13,231 2,610 Other 4,635 4,698 Total accrued expenses and other current liabilities $ 160,732 $ 140,406

Long-Term Debt (Tables)

Long-Term Debt (Tables)	9 Months Ended
	Sep. 30, 2021
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	Long-term debt consisted of the following: September 30, 2021 December 31, 2020 Term Loan Credit Facility - due June 2024 $ 499,435 $ 553,373 ABL Facility - due April 2022 — 3,350 LCC Note Payable 2,300 27,500 LCC Water Treatment Obligation 5,625 6,875 Other (1) 6,083 8,475 Debt discount and issuance costs (8,276) (17,046) Total long-term debt 505,167 582,527 Less current portion (7,976) (28,830) Long-term debt, net of current portion $ 497,191 $ 553,697 (1) Includes financing leases.

Acquisition-Related Obligatio_2

Acquisition-Related Obligations (Tables)	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Schedule of Acquisition-Related Obligations	Acquisition-related obligations consisted of the following: September 30, 2021 December 31, 2020 Contingent Revenue Obligation $ 35,580 $ 28,967 Environmental Settlement Obligations 8,139 10,391 UMWA Funds Settlement Liability 2,000 2,000 Discount (487) (1,491) Total acquisition-related obligations 45,232 39,867 Less current portion (26,266) (19,099) Acquisition-related obligations, net of current portion $ 18,966 $ 20,768

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	9 Months Ended
	Sep. 30, 2021
Asset Retirement Obligation Disclosure [Abstract]
Summary of Changes in Asset Retirement Obligations	The following table summarizes the changes in asset retirement obligations for the nine months ended September 30, 2021: Total asset retirement obligations at December 31, 2020 $ 165,064 Accretion for the period 19,970 Sites added during the period 756 Revisions in estimated cash flows (500) Expenditures for the period (12,630) Total asset retirement obligations at September 30, 2021 172,660 Less current portion (1) (30,735) Long-term portion $ 141,925 (1) Included within accrued expenses and other current liabilities on the Company’s Condensed Consolidated Balance Sheets. Refer to Note 8.

Fair Value of Financial Instr_2

Fair Value of Financial Instruments and Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements, Nonrecurring	The following tables set forth by level, within the fair value hierarchy, the Company’s long-term debt at fair value as of September 30, 2021 and December 31, 2020: September 30, 2021 Carrying Amount (1) Total Fair Value Quoted Prices in Active Markets Significant Other Observable Inputs Significant Unobservable Inputs Term Loan Credit Facility - due June 2024 $ 492,092 $ 494,753 $ — $ 494,753 $ — LCC Note Payable 2,066 2,054 — — 2,054 LCC Water Treatment Obligation 4,926 4,902 — — 4,902 Total long-term debt $ 499,084 $ 501,709 $ — $ 494,753 $ 6,956 December 31, 2020 Carrying Amount (1) Total Fair Value Quoted Prices in Active Markets Significant Other Observable Inputs Significant Unobservable Inputs Term Loan Credit Facility - due June 2024 $ 540,643 $ 379,614 $ — $ 379,614 $ — ABL Facility - due April 2022 3,350 3,057 — — 3,057 LCC Note Payable 24,423 20,328 — — 20,328 LCC Water Treatment Obligation 5,636 4,281 — — 4,281 Total long-term debt $ 574,052 $ 407,280 $ — $ 379,614 $ 27,666 (1) Net of debt discounts and debt issuance costs. The following tables set forth by level, within the fair value hierarchy, the Company’s acquisition-related obligations at fair value as of September 30, 2021 and December 31, 2020: September 30, 2021 Carrying Amount (1) Total Fair Value Quoted Prices in Active Markets Significant Other Observable Inputs Significant Unobservable Inputs UMWA Funds Settlement Liability $ 1,910 $ 1,934 $ — $ — $ 1,934 Environmental Settlement Obligations 7,742 7,723 — — 7,723 Total acquisition-related obligations $ 9,652 $ 9,657 $ — $ — $ 9,657 December 31, 2020 Carrying Amount (1) Total Fair Value Quoted Prices in Active Markets Significant Other Observable Inputs Significant Unobservable Inputs UMWA Funds Settlement Liability $ 1,662 $ 1,426 $ — $ — $ 1,426 Environmental Settlement Obligations 9,237 7,760 — — 7,760 Total acquisition-related obligations $ 10,899 $ 9,186 $ — $ — $ 9,186 (1) Net of discounts.
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The following table sets forth by level, within the fair value hierarchy, the Company’s financial and non-financial assets and liabilities that were accounted for at fair value on a recurring basis as of September 30, 2021 and December 31, 2020. Financial and non-financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company’s assessment of the significance of a particular input to the fair value measurement requires judgment, and may affect the determination of fair value for assets and liabilities and their placement within the fair value hierarchy levels. September 30, 2021 Total Fair Value Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Contingent Revenue Obligation $ 35,580 $ — $ — $ 35,580 Trading securities $ 28,695 $ 27,074 $ 1,621 $ — December 31, 2020 Total Fair Value Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Contingent Revenue Obligation $ 28,967 $ — $ — $ 28,967 Trading securities $ 22,498 $ 20,092 $ 2,406 $ — The following tables present a reconciliation of the financial and non-financial assets and liabilities that were accounted for at fair value on a recurring basis and that were categorized within Level 3 of the fair value hierarchy: December 31, 2020 Payments Loss (Gain) Recognized in Earnings (1) Transfer In (Out) of Level 3 Fair Value Hierarchy September 30, 2021 Contingent Revenue Obligation $ 28,967 $ (11,396) $ 18,009 $ — $ 35,580 (1) The loss recognized in earnings resulted primarily from an increase in forecasted future revenue as of September 30, 2021. December 31, 2019 Payments Loss (Gain) Recognized in Earnings (1) Transfer In (Out) of Level 3 Fair Value Hierarchy September 30, 2020 Contingent Revenue Obligation $ 52,427 $ (14,710) $ (13,425) $ — $ 24,292 (1) The gain recognized in earnings resulted primarily from a change in the forecasted future revenue associated with this obligation and an increase in annualized volatility as of September 30, 2020.
Range of Significant Unobservable Inputs	The range of significant unobservable inputs used to value the contingent revenue obligation as of September 30, 2021 and December 31, 2020, are set forth in the following table: September 30, 2021 December 31, 2020 Forecasted future revenue $1.4 - $2.0 billion $0.9 - $1.1 billion Stated royalty rate 1.0% - 1.5% 1.0% - 1.5% Annualized volatility 19.6% - 37.9% (34.2%) 19.4% - 52.1% (28.0%)

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	9 Months Ended
	Sep. 30, 2021
Compensation Related Costs [Abstract]
Schedule of Net Periodic Benefit Cost	The following table details the components of the net periodic benefit for pension obligations: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Interest cost $ 3,392 $ 4,670 $ 10,176 $ 14,061 Expected return on plan assets (7,183) (6,752) (21,549) (20,312) Amortization of net actuarial loss 804 511 2,413 1,501 Settlement — — — 1,230 Net periodic benefit $ (2,987) $ (1,571) $ (8,960) $ (3,520) The following table details the components of the net periodic expense for black lung obligations: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Service cost $ 739 $ 499 $ 2,217 $ 1,479 Interest cost 607 678 1,821 2,275 Expected return on plan assets (14) (13) (42) (40) Amortization of net actuarial loss 522 426 1,566 927 Net periodic expense $ 1,854 $ 1,590 $ 5,562 $ 4,641

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Schedule of Restricted Cash Deposits	Amounts included in restricted cash represent cash deposits primarily invested in interest bearing accounts that are restricted as to withdrawal as required by certain agreements entered into by the Company and provide collateral to secure the following obligations which have been written on the Company’s behalf: September 30, 2021 December 31, 2020 Workers' compensation and black lung obligations $ 66,488 $ 69,725 Reclamation-related obligations 10,580 8,445 Financial payments and other performance obligations 6,933 17,863 Contingent revenue obligation escrow 7,642 9,311 Total restricted cash 91,643 105,344 Less current portion (1) (7,642) (9,311) Restricted cash, net of current portion $ 84,001 $ 96,033 (1) Included within prepaid expenses and other current assets on the Company’s Condensed Consolidated Balance Sheets.
Schedule of Restricted Investments and Deposit Assets	Restricted investments consist of Federal Deposit Insurance Company (“FDIC”) insured certificates of deposit, mutual funds, and U.S. treasury bills that are restricted as to withdrawal as required by certain agreements entered into by the Company and provide collateral to secure the following obligations which have been written on the Company’s behalf: September 30, 2021 December 31, 2020 Workers' compensation obligations $ 211 $ 51 Reclamation-related obligations 26,467 22,233 Financial payments and other performance obligations 2,017 1,484 Total restricted investments (1), (2) $ 28,695 $ 23,768 (1) Included within other non-current assets on the Company’s Condensed Consolidated Balance Sheets. (2) As of September 30, 2021 and December 31, 2020, respectively, $28,695 and $22,498 are classified as trading securities and $0 and $1,270 are classified as held-to-maturity securities. Deposits represent cash deposits held at third parties as required by certain agreements entered into by the Company to provide cash collateral to secure the following obligations which have been written on the Company’s behalf: September 30, 2021 December 31, 2020 Reclamation-related obligations $ 117 $ 25,633 Financial payments and other performance obligations 403 1,596 Other operating agreements 881 1,018 Total deposits (1) $ 1,401 $ 28,247 (1) Included within prepaid expenses and other current assets and other non-current assets on the Company’s Condensed Consolidated Balance Sheets.

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2021
Segment Reporting [Abstract]
Schedule of Segment Operating Results and Capital Expenditures	Segment operating results and capital expenditures for the three months ended September 30, 2021 and 2020 were as follows: Three Months Ended September 30, 2021 Met All Other Consolidated Total revenues $ 626,103 $ 22,738 $ 648,841 Depreciation, depletion, and amortization $ 23,181 $ 1,338 $ 24,519 Amortization of acquired intangibles, net $ 3,063 $ (83) $ 2,980 Adjusted EBITDA $ 155,456 $ (7,234) $ 148,222 Capital expenditures $ 21,882 $ 465 $ 22,347 Three Months Ended September 30, 2020 Met All Other Consolidated Total revenues $ 295,381 $ 40,211 $ 335,592 Depreciation, depletion, and amortization $ 41,178 $ 8,058 $ 49,236 Amortization of acquired intangibles, net $ 2,535 $ (461) $ 2,074 Adjusted EBITDA $ 17,772 $ (5,412) $ 12,360 Capital expenditures $ 22,668 $ 839 $ 23,507 Segment operating results and capital expenditures for the nine months ended September 30, 2021 and 2020 were as follows: Nine Months Ended September 30, 2021 Met All Other Consolidated Total revenues $ 1,363,918 $ 66,451 $ 1,430,369 Depreciation, depletion, and amortization $ 75,403 $ 4,858 $ 80,261 Amortization of acquired intangibles, net $ 9,749 $ (347) $ 9,402 Adjusted EBITDA $ 234,824 $ (17,801) $ 217,023 Capital expenditures $ 59,408 $ 978 $ 60,386 Nine Months Ended September 30, 2020 Met All Other Consolidated Total revenues $ 974,674 $ 117,662 $ 1,092,336 Depreciation, depletion, and amortization $ 121,679 $ 22,242 $ 143,921 Amortization of acquired intangibles, net $ 7,875 $ (3,409) $ 4,466 Adjusted EBITDA $ 104,408 $ (28,406) $ 76,002 Capital expenditures $ 83,449 $ 6,979 $ 90,428 Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Total coal revenues $ 647,129 $ 335,189 $ 1,426,039 $ 1,089,764 Export coal revenues $ 516,877 $ 205,576 $ 1,016,677 $ 697,692 Export coal revenues as % of total coal revenues 80 % 61 % 71 % 64 % Countries with export coal revenue exceeding 10% of total revenue China, India India China, India, Brazil India, Brazil
Reconciliation of Net Income (Loss) to Adjusted EBITDA	The following tables present a reconciliation of net income (loss) to Adjusted EBITDA for the three months ended September 30, 2021 and 2020: Three Months Ended September 30, 2021 Met All Other Consolidated Net income (loss) from continuing operations $ 125,750 $ (42,057) $ 83,693 Interest expense 49 17,289 17,338 Interest income (1) (53) (54) Income tax expense — 208 208 Depreciation, depletion and amortization 23,181 1,338 24,519 Non-cash stock compensation expense 6 1,182 1,188 Mark-to-market adjustment - acquisition-related obligations — 11,676 11,676 Accretion on asset retirement obligations 3,408 3,266 6,674 Amortization of acquired intangibles, net 3,063 (83) 2,980 Adjusted EBITDA $ 155,456 $ (7,234) $ 148,222 Three Months Ended September 30, 2020 Met All Other Consolidated Net loss from continuing operations $ (29,656) $ (38,832) $ (68,488) Interest expense (188) 18,934 18,746 Interest income (2) (374) (376) Income tax benefit — (45) (45) Depreciation, depletion and amortization 41,178 8,058 49,236 Non-cash stock compensation expense 105 973 1,078 Mark-to-market adjustment - acquisition-related obligations — 3,624 3,624 Accretion on asset retirement obligations 3,800 2,937 6,737 Asset impairment and restructuring (1) — (226) (226) Amortization of acquired intangibles, net 2,535 (461) 2,074 Adjusted EBITDA $ 17,772 $ (5,412) $ 12,360 (1) Refer to Note 7 for additional information on asset impairment and restructuring during the period. The following tables present a reconciliation of net income (loss) to Adjusted EBITDA for the nine months ended September 30, 2021 and 2020: Nine Months Ended September 30, 2021 Met All Other Consolidated Net income (loss) from continuing operations $ 139,354 $ (106,942) $ 32,412 Interest expense 132 53,158 53,290 Interest income (6) (316) (322) Income tax expense — 211 211 Depreciation, depletion and amortization 75,403 4,858 80,261 Non-cash stock compensation expense 22 4,329 4,351 Mark-to-market adjustment - acquisition-related obligations — 18,009 18,009 Accretion on asset retirement obligations 10,170 9,800 19,970 Asset impairment and restructuring (1) — (561) (561) Amortization of acquired intangibles, net 9,749 (347) 9,402 Adjusted EBITDA $ 234,824 $ (17,801) $ 217,023 (1) Refer to Note 7 for additional information on asset impairment and restructuring during the period. Nine Months Ended September 30, 2020 Met All Other Consolidated Net loss from continuing operations $ (68,338) $ (118,082) $ (186,420) Interest expense (1,494) 57,732 56,238 Interest income (63) (6,811) (6,874) Income tax benefit — (2,200) (2,200) Depreciation, depletion and amortization 121,679 22,242 143,921 Non-cash stock compensation expense 410 3,790 4,200 Mark-to-market adjustment - acquisition-related obligations — (13,425) (13,425) Accretion on asset retirement obligations 10,887 9,058 19,945 Asset impairment and restructuring (1) 32,951 21,030 53,981 Management restructuring costs (2) 501 439 940 Loss on partial settlement of benefit obligations — 1,230 1,230 Amortization of acquired intangibles, net 7,875 (3,409) 4,466 Adjusted EBITDA $ 104,408 $ (28,406) $ 76,002 (1) Refer to Note 7 for additional information on asset impairment and restructuring during the period. (2) Management restructuring costs are related to severance expense associated with senior management changes in the three months ended March 31, 2020.

Discontinued Operations - Narra

Discontinued Operations - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Guarantor Obligations [Line Items]
Loss from discontinued operations before income taxes	$ (429)	$ (149)	$ (1,067)	$ (160,326)
Discontinued Operations, Disposed of by Sale | Cumberland Transaction
Guarantor Obligations [Line Items]
Remaining surety bond and expected to be released in short-term	$ 30		$ 30

Discontinued Operations - Major

Discontinued Operations - Major Components of Net Income (Loss) (Details) - Cumberland and PRB Transaction - Discontinued Operations - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020
Revenues:
Total revenues	$ 65,100	$ 190,654
Costs and expenses:
Cost of coal sales (exclusive of items shown separately below)	57,398	167,663
Depreciation, depletion and amortization	1,503	10,545
Accretion on asset retirement obligations	2,390	3,861
Selling, general and administrative expenses	186	1,573
Asset impairment and restructuring	3,797	167,472
Other non-major income items, net	(25)	(134)
Loss from discontinued operations before income taxes	$ (149)	$ (160,326)

Discontinued Operations - Maj_2

Discontinued Operations - Major Components of Asset and Liabilities (Details) - Cumberland and PRB Transaction - Discontinued Operations - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Assets:
Trade accounts receivable, net of allowance for doubtful accounts	$ 0	$ 7,504
Prepaid expenses and other current assets	1,391	3,431
Other non-current assets	9,477	9,473
Liabilities:
Trade accounts payable, accrued expenses and other current liabilities	7,095	12,306
Workers’ compensation and black lung obligations, non-current	25,449	27,799
Other non-current liabilities	$ 1,291	$ 1,291

Discontinued Operations - Maj_3

Discontinued Operations - Major Components of Cash Flows (Details) - Cumberland and PRB Transaction - Discontinued Operations - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Depreciation, depletion and amortization		$ 10,545
Capital expenditures		28,468
Other significant operating non-cash items related to discontinued operations:
Accretion on asset retirement obligations	$ 2,390	3,861
Asset impairment and restructuring		$ 167,472

Revenue - Disaggregation of Rev

Revenue - Disaggregation of Revenue by Segment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Revenues	$ 647,129	$ 335,189	$ 1,426,039	$ 1,089,764
Coal
Disaggregation of Revenue [Line Items]
Revenues	647,129	335,189	1,426,039	1,089,764
Met Coal
Disaggregation of Revenue [Line Items]
Revenues	595,681	283,544	1,294,234	955,499
Thermal Coal
Disaggregation of Revenue [Line Items]
Revenues	51,448	51,645	131,805	134,265
Non-US
Disaggregation of Revenue [Line Items]
Revenues	516,877	205,576	1,016,677	697,692
Non-US | Coal
Disaggregation of Revenue [Line Items]
Revenues	516,877	205,576	1,016,677	697,692
Non-US | Met Coal
Disaggregation of Revenue [Line Items]
Revenues	503,566	198,869	996,642	673,233
Non-US | Thermal Coal
Disaggregation of Revenue [Line Items]
Revenues	13,311	6,707	20,035	24,459
Domestic coal revenues | Coal
Disaggregation of Revenue [Line Items]
Revenues	130,252	129,613	409,362	392,072
Domestic coal revenues | Met Coal
Disaggregation of Revenue [Line Items]
Revenues	92,115	84,675	297,592	282,266
Domestic coal revenues | Thermal Coal
Disaggregation of Revenue [Line Items]
Revenues	$ 38,137	$ 44,938	$ 111,770	$ 109,806

Revenue - Performance Obligatio

Revenue - Performance Obligations (Details) $ in Thousands	Sep. 30, 2021USD ($)
Disaggregation of Revenue [Line Items]
Estimated coal revenues	$ 99,845
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-10-01
Disaggregation of Revenue [Line Items]
Estimated coal revenues	$ 35,932
Revenue, remaining performance obligation, period	3 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Disaggregation of Revenue [Line Items]
Estimated coal revenues	$ 53,500
Revenue, remaining performance obligation, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Disaggregation of Revenue [Line Items]
Estimated coal revenues	$ 10,413
Revenue, remaining performance obligation, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Disaggregation of Revenue [Line Items]
Estimated coal revenues	$ 0
Revenue, remaining performance obligation, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Disaggregation of Revenue [Line Items]
Estimated coal revenues	$ 0
Revenue, remaining performance obligation, period	1 year

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Loss - Changes to Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 200,102	$ 696,122
Ending balance	248,097	342,968
Employee benefit costs
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(111,985)	(58,616)
Other comprehensive income before reclassifications	8,838	(14,154)
Amounts reclassified from accumulated other comprehensive loss	4,239	4,156
Ending balance	$ (98,908)	$ (68,614)

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Loss - Summary of Amounts Reclassified (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Employee benefit costs:
Miscellaneous income (loss), net	$ (1,812)			$ 131			$ (5,425)	$ 452
Total before income tax	(83,901)			68,533			(32,623)	188,620
Income tax	(208)			45			(211)	2,200
Total, net of income tax	(83,264)	$ 18,991	$ 32,928	68,637	$ 238,301	$ 39,808	(31,345)	346,746
Amounts reclassified from accumulated other comprehensive loss | Amortization of actuarial loss
Employee benefit costs:
Miscellaneous income (loss), net	1,413			1,101			4,239	2,829
Amounts reclassified from accumulated other comprehensive loss | Settlement
Employee benefit costs:
Miscellaneous income (loss), net	0			32			0	1,327
Amounts reclassified from accumulated other comprehensive loss | Employee benefit costs
Employee benefit costs:
Total before income tax	1,413			1,133			4,239	4,156
Income tax	0			0			0	0
Total, net of income tax	$ 1,413			$ 1,133			$ 4,239	$ 4,156

Net Income (Loss) Per Share - N

Net Income (Loss) Per Share - Narrative (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share [Abstract]
Antidilutive securities excluded from computation of earnings per share (in shares)	942,408	1,243,866	948,351	1,380,076
Weighted-average antidilutive securities excluded from computation of earnings per share (in shares)		31,665		38,648

Net Income (Loss) Per Share - S

Net Income (Loss) Per Share - Schedule of Net (Loss) Income Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Net income (loss)
Income (loss) from continuing operations	$ 83,693			$ (68,488)			$ 32,412	$ (186,420)
Loss from discontinued operations	(429)			(149)			(1,067)	(160,326)
Net income (loss)	$ 83,264	$ (18,991)	$ (32,928)	$ (68,637)	$ (238,301)	$ (39,808)	$ 31,345	$ (346,746)
Basic
Weighted average common shares outstanding - basic (in shares)	18,445,709			18,319,947			18,426,639	18,290,346
Basic income (loss) per common share:
Income (loss) from continuing operations (in dollars per share)	$ 4.54			$ (3.74)			$ 1.76	$ (10.19)
Loss from discontinued operations (in dollars per share)	(0.03)			(0.01)			(0.06)	(8.77)
Net income (loss) (in dollars per share)	$ 4.51			$ (3.75)			$ 1.70	$ (18.96)
Diluted
Weighted average common shares outstanding - basic (in shares)	18,445,709			18,319,947			18,426,639	18,290,346
Weighted average common shares outstanding - diluted (in shares)	18,913,352			18,319,947			18,783,643	18,290,346
Diluted income (loss) per common share:
Income (loss) from continuing operations (in dollars per share)	$ 4.43			$ (3.74)			$ 1.73	$ (10.19)
Loss from discontinued operations (in dollars per share)	(0.03)			(0.01)			(0.06)	(8.77)
Net income (loss) (in dollars per share)	$ 4.40			$ (3.75)			$ 1.67	$ (18.96)
Stock Options
Diluted
Dilutive effect of share-based payment awards (in shares)	1,938			0			1,654	0
Other Stock-Based Instruments
Diluted
Dilutive effect of share-based payment awards (in shares)	465,705			0			355,350	0

Inventories, net (Details)

Inventories, net (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Inventory [Line Items]
Total inventories, net	$ 124,534	$ 108,051
Coal
Inventory [Line Items]
Raw coal	21,025	15,084
Saleable coal	74,948	69,262
Material, supplies and other, net
Inventory [Line Items]
Materials, supplies and other, net	$ 28,561	$ 23,705

Asset Impairment and Restruct_3

Asset Impairment and Restructuring - Long-Lived Asset Impairment (Details) $ in Thousands	Aug. 31, 2020assetGroup	May 31, 2020assetGroup	Feb. 29, 2020assetGroup	Sep. 30, 2020USD ($)	Jun. 30, 2020mine	Sep. 30, 2021USD ($)	Sep. 30, 2020USD ($)
Impaired Long-Lived Assets Held and Used [Line Items]
Number of coal mining complexes evaluated | mine					2
Total from continuing operations				$ 219			$ 51,318
Asset impairment related to write-off of prepaid purchase coal				3,297			147,645
Total long-lived asset impairment				3,516			198,963
Mineral rights, net
Impaired Long-Lived Assets Held and Used [Line Items]
Total from continuing operations				0			24,066
Asset impairment related to write-off of prepaid purchase coal				0			16,364
Total long-lived asset impairment				0			40,430
Property, plant, and equipment, net
Impaired Long-Lived Assets Held and Used [Line Items]
Total from continuing operations				219			12,781
Asset impairment related to write-off of prepaid purchase coal				3,297			131,281
Total long-lived asset impairment				3,516			144,062
Acquired mine permits, net
Impaired Long-Lived Assets Held and Used [Line Items]
Total from continuing operations				0			14,471
Total long-lived asset impairment				0			14,471
Met
Impaired Long-Lived Assets Held and Used [Line Items]
Total from continuing operations				0			32,951
All Other
Impaired Long-Lived Assets Held and Used [Line Items]
Number of assets impaired | assetGroup	4	4	3
Total from continuing operations				$ 219			$ 18,367
Total long-lived asset impairment						$ 60
Operating Segments | Met
Impaired Long-Lived Assets Held and Used [Line Items]
Number of assets impaired | assetGroup	3	3	4

Asset Impairment and Restruct_4

Asset Impairment and Restructuring - Restructuring Expense (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Restructuring Cost and Reserve [Line Items]
Severance and employee-related benefits			$ 940
Strategic Actions with Respect to Two Thermal Coal Mining Complexes
Restructuring Cost and Reserve [Line Items]
Severance and employee-related benefits	$ 55		20,608
Other costs			1,882
Restructuring expense	55		22,490
Deferred longwall move expenses			668
Allowance for advanced mining royalties			407
Allowance for obsolete materials and supplies inventory			807
Strategic Actions with Respect to Two Thermal Coal Mining Complexes | Continuing operations
Restructuring Cost and Reserve [Line Items]
Severance and employee-related benefits	(445)		1,856
Other costs			807
Restructuring expense	(445)		2,663
Strategic Actions with Respect to Two Thermal Coal Mining Complexes | Discontinued Operations
Restructuring Cost and Reserve [Line Items]
Severance and employee-related benefits	500		18,752
Other costs			1,075
Restructuring expense	500		19,827
All Other
Restructuring Cost and Reserve [Line Items]
Severance and employee-related benefits			439
All Other | Strategic Actions with Respect to Two Thermal Coal Mining Complexes
Restructuring Cost and Reserve [Line Items]
Restructuring expense		$ (621)
All Other | Strategic Actions with Respect to Two Thermal Coal Mining Complexes | Continuing operations
Restructuring Cost and Reserve [Line Items]
Restructuring expense	$ (445)		$ 2,663

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Payables and Accruals [Abstract]
Wages and benefits	$ 53,746	$ 40,330
Workers’ compensation	10,355	10,355
Black lung	6,784	6,784
Taxes other than income taxes	24,202	21,540
Current portion of asset retirement obligations	30,735	24,990
Accrued interest and fees	16,102	15,902
Deferred revenue	942	13,197
Freight accrual	13,231	2,610
Other	4,635	4,698
Accrued expenses and other current liabilities	$ 160,732	$ 140,406

Long-Term Debt - Schedule of Lo

Long-Term Debt - Schedule of Long-Term Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Debt discount and issuance costs	$ (8,276)	$ (17,046)
Total long-term debt	505,167	582,527
Less current portion	(7,976)	(28,830)
Long-term debt, net of current portion	497,191	553,697
Term Loan Credit Facility | Term Loan Credit Facility - due June 2024
Debt Instrument [Line Items]
Long-term debt	499,435	553,373
Line of Credit | ABL Facility - due April 2022
Debt Instrument [Line Items]
Long-term debt	0	3,350
Note Payable | LCC Note Payable
Debt Instrument [Line Items]
Long-term debt	2,300	27,500
Less current portion	(2,066)	(17,500)
Note Payable | LCC Water Treatment Obligation
Debt Instrument [Line Items]
Long-term debt	5,625	6,875
Other
Debt Instrument [Line Items]
Long-term debt	$ 6,083	$ 8,475

Long-Term Debt - Term Loan and

Long-Term Debt - Term Loan and Revolving Credit (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Debt Instrument [Line Items]
Repurchase of debt, net of discount		$ 18,415	$ 0
Term Loan Credit Facility - due June 2024
Debt Instrument [Line Items]
Payment of borrowings	$ 31
Term Loan Credit Facility | Term Loan Credit Facility - due June 2024
Debt Instrument [Line Items]
Outstanding borrowings	492,092	492,092		$ 540,643
Current portion of long-term debt				5,618
Repurchased amount	18,724	$ 18,724
Repurchase of debt, net of discount	$ 18,415
Term Loan Credit Facility | Term Loan Credit Facility - due June 2024 | Eurocurrency
Debt Instrument [Line Items]
Interest rate at period end (as a percent)	10.00%	10.00%
Basis spread on variable rate (as a percent)		8.00%
Line of Credit | ABL Facility - due April 2022 | Revolving Credit Facility
Debt Instrument [Line Items]
Outstanding borrowings	$ 0	$ 0		3,350
Expected borrowing capacity	150,000	150,000
Letters of credit outstanding	$ 120,037	$ 120,037		$ 123,108

Long-Term Debt - LCC Note Payab

Long-Term Debt - LCC Note Payable (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Jul. 26, 2021	Dec. 31, 2020	Nov. 09, 2018
Business Acquisition, Contingent Consideration [Line Items]
Current portion of long-term debt	$ 7,976		$ 28,830
Notes Payable, Other Payables | LCC Note Payable
Business Acquisition, Contingent Consideration [Line Items]
Aggregate amount of debt				$ 62,500
Stated interest rate				0.00%
Imputed interest rate (as a percent)				12.45%
Principle repayment year one				$ 17,500
Principle repayment year two				17,500
Principle repayment year three				17,500
Final principal payment				$ 10,000
Outstanding borrowings	2,066		24,423
Current portion of long-term debt	2,066		$ 17,500
Notes Payable, Other Payables | LCC Note Payable | West Virginia
Business Acquisition, Contingent Consideration [Line Items]
Final principal payment		$ 7,700
Surety collateral returned		$ 13,982
Notes Payable, Other Payables | LCC Note Payable | Kentucky
Business Acquisition, Contingent Consideration [Line Items]
Outstanding borrowings	$ 2,300

Acquisition-Related Obligatio_3

Acquisition-Related Obligations - Summary of Acquisition-Related Obligations (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Fair Value, Option, Quantitative Disclosures [Line Items]
Discount	$ (487)	$ (1,491)
Total acquisition-related obligations	45,232	39,867
Less current portion	(26,266)	(19,099)
Acquisition-related obligations, net of current portion	18,966	20,768
Contingent Revenue Obligation
Fair Value, Option, Quantitative Disclosures [Line Items]
Total acquisition-related obligations - long-term, gross	35,580	28,967
Total acquisition-related obligations	35,580	28,967
Less current portion	(16,614)	(11,393)
Environmental Settlement Obligations
Fair Value, Option, Quantitative Disclosures [Line Items]
Total acquisition-related obligations - long-term, gross	8,139	10,391
UMWA Funds Settlement Liability
Fair Value, Option, Quantitative Disclosures [Line Items]
Total acquisition-related obligations - long-term, gross	$ 2,000	$ 2,000

Acquisition-Related Obligatio_4

Acquisition-Related Obligations - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2021	Sep. 30, 2021	Dec. 31, 2020
Business Acquisition, Contingent Consideration [Line Items]
Acquisition related obligations		$ 45,232	$ 39,867
Acquisition related obligations, current		26,266	19,099
Contingent Revenue Obligation
Business Acquisition, Contingent Consideration [Line Items]
Acquisition related obligations		35,580	28,967
Acquisition related obligations, current		$ 16,614	$ 11,393
Payments for acquisition-related obligations	$ 11,396

Asset Retirement Obligations (D

Asset Retirement Obligations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Total asset retirement obligations at December 31, 2020			$ 165,064
Accretion for the period	$ 6,674	$ 6,737	19,970	$ 19,945
Sites added during the period			756
Revisions in estimated cash flows			(500)
Expenditures for the period			(12,630)
Total asset retirement obligations at September 30, 2021	172,660		172,660		$ 165,064
Less current portion	(30,735)		(30,735)		(24,990)
Long-term portion	$ 141,925		$ 141,925		$ 140,074

Fair Value of Financial Instr_3

Fair Value of Financial Instruments and Fair Value Measurements - Summary of Long-Term Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	$ 499,084	$ 574,052
Carrying Amount | Term Loan Agreement | Term Loan Credit Facility - due June 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	492,092	540,643
Carrying Amount | Line of Credit | ABL Facility - due April 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt		3,350
Carrying Amount | Note Payable | LCC Note Payable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	2,066	24,423
Carrying Amount | Note Payable | LCC Water Treatment Obligation
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	4,926	5,636
Fair Value, Measurements, Nonrecurring | Total Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	501,709	407,280
Fair Value, Measurements, Nonrecurring | Total Fair Value | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	0	0
Fair Value, Measurements, Nonrecurring | Total Fair Value | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	494,753	379,614
Fair Value, Measurements, Nonrecurring | Total Fair Value | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	6,956	27,666
Fair Value, Measurements, Nonrecurring | Total Fair Value | Term Loan Agreement | Term Loan Credit Facility - due June 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	494,753	379,614
Fair Value, Measurements, Nonrecurring | Total Fair Value | Term Loan Agreement | Term Loan Credit Facility - due June 2024 | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	0	0
Fair Value, Measurements, Nonrecurring | Total Fair Value | Term Loan Agreement | Term Loan Credit Facility - due June 2024 | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	494,753	379,614
Fair Value, Measurements, Nonrecurring | Total Fair Value | Term Loan Agreement | Term Loan Credit Facility - due June 2024 | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	0	0
Fair Value, Measurements, Nonrecurring | Total Fair Value | Line of Credit | ABL Facility - due April 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt		3,057
Fair Value, Measurements, Nonrecurring | Total Fair Value | Line of Credit | ABL Facility - due April 2022 | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt		0
Fair Value, Measurements, Nonrecurring | Total Fair Value | Line of Credit | ABL Facility - due April 2022 | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt		0
Fair Value, Measurements, Nonrecurring | Total Fair Value | Line of Credit | ABL Facility - due April 2022 | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt		3,057
Fair Value, Measurements, Nonrecurring | Total Fair Value | Note Payable | LCC Note Payable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	2,054	20,328
Fair Value, Measurements, Nonrecurring | Total Fair Value | Note Payable | LCC Note Payable | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	0	0
Fair Value, Measurements, Nonrecurring | Total Fair Value | Note Payable | LCC Note Payable | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	0	0
Fair Value, Measurements, Nonrecurring | Total Fair Value | Note Payable | LCC Note Payable | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	2,054	20,328
Fair Value, Measurements, Nonrecurring | Total Fair Value | Note Payable | LCC Water Treatment Obligation
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	4,902	4,281
Fair Value, Measurements, Nonrecurring | Total Fair Value | Note Payable | LCC Water Treatment Obligation | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	0	0
Fair Value, Measurements, Nonrecurring | Total Fair Value | Note Payable | LCC Water Treatment Obligation | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	0	0
Fair Value, Measurements, Nonrecurring | Total Fair Value | Note Payable | LCC Water Treatment Obligation | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	$ 4,902	$ 4,281

Fair Value of Financial Instr_4

Fair Value of Financial Instruments and Fair Value Measurements - Acquisition-related Obligations at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Acquisition-related obligations	$ 9,652	$ 10,899
Carrying Amount | UMWA Funds Settlement Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Acquisition-related obligations	1,910	1,662
Carrying Amount | Environmental Settlement Obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Acquisition-related obligations	7,742	9,237
Fair Value, Measurements, Nonrecurring | Total Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Acquisition-related obligations	9,657	9,186
Fair Value, Measurements, Nonrecurring | Total Fair Value | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Acquisition-related obligations	0	0
Fair Value, Measurements, Nonrecurring | Total Fair Value | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Acquisition-related obligations	0	0
Fair Value, Measurements, Nonrecurring | Total Fair Value | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Acquisition-related obligations	9,657	9,186
Fair Value, Measurements, Nonrecurring | Total Fair Value | UMWA Funds Settlement Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Acquisition-related obligations	1,934	1,426
Fair Value, Measurements, Nonrecurring | Total Fair Value | UMWA Funds Settlement Liability | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Acquisition-related obligations	0	0
Fair Value, Measurements, Nonrecurring | Total Fair Value | UMWA Funds Settlement Liability | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Acquisition-related obligations	0	0
Fair Value, Measurements, Nonrecurring | Total Fair Value | UMWA Funds Settlement Liability | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Acquisition-related obligations	1,934	1,426
Fair Value, Measurements, Nonrecurring | Total Fair Value | Environmental Settlement Obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Acquisition-related obligations	7,723	7,760
Fair Value, Measurements, Nonrecurring | Total Fair Value | Environmental Settlement Obligations | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Acquisition-related obligations	0	0
Fair Value, Measurements, Nonrecurring | Total Fair Value | Environmental Settlement Obligations | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Acquisition-related obligations	0	0
Fair Value, Measurements, Nonrecurring | Total Fair Value | Environmental Settlement Obligations | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Acquisition-related obligations	$ 7,723	$ 7,760

Fair Value of Financial Instr_5

Fair Value of Financial Instruments and Fair Value Measurements - Schedule of Fair Value on Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Contingent Revenue Obligation	$ 35,580	$ 28,967
Trading securities	28,695	22,498
Quoted Prices in Active Markets (Level 1)
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Contingent Revenue Obligation	0	0
Trading securities	27,074	20,092
Significant Other Observable Inputs (Level 2)
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Contingent Revenue Obligation	0	0
Trading securities	1,621	2,406
Significant Unobservable Inputs (Level 3)
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Contingent Revenue Obligation	35,580	28,967
Trading securities	$ 0	$ 0

Fair Value of Financial Instr_6

Fair Value of Financial Instruments and Fair Value Measurements - Level 3 of the Fair Value Hierarchy (Details) - Significant Unobservable Inputs (Level 3) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	$ 28,967	$ 52,427
Payments	(11,396)	(14,710)
Loss (Gain) Recognized in Earnings	18,009	(13,425)
Transfer In (Out) of Level 3 Fair Value Hierarchy	0	0
Ending balance	$ 35,580	$ 24,292

Fair Value of Financial Instr_7

Fair Value of Financial Instruments and Fair Value Measurements - Level 3 Fair Value Measurements (Details) $ in Billions	Sep. 30, 2021USD ($)	Dec. 31, 2020USD ($)
Black Scholes | Forecasted future revenue | Minimum | Contingent Revenue Obligation
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Acquisition-related obligation, measurement input	1.4	0.9
Black Scholes | Forecasted future revenue | Maximum | Contingent Revenue Obligation
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Acquisition-related obligation, measurement input	2	1.1
Black Scholes | Stated royalty rate | Minimum | Contingent Revenue Obligation
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Acquisition-related obligation, measurement input	0.010	0.010
Black Scholes | Stated royalty rate | Maximum | Contingent Revenue Obligation
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Acquisition-related obligation, measurement input	0.015	0.015
Black Scholes | Annualized volatility | Minimum | Contingent Revenue Obligation
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Acquisition-related obligation, measurement input	0.196	0.194
Black Scholes | Annualized volatility | Maximum | Contingent Revenue Obligation
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Acquisition-related obligation, measurement input	0.379	0.521
Black Scholes | Annualized volatility | Weighted Average | Contingent Revenue Obligation
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Acquisition-related obligation, measurement input	0.342	0.280
Fair Value, Measurements, Recurring | Discounted cash flow | Significant Unobservable Inputs (Level 3) | Discount rate | Notes Payable, UMWA Funds Settlement Liability, Enviromental Settlement Obligations, and Reclaimation Funding Liability,
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Debt and acquisition-related obligation, measurement input	0.14	0.34
Line of Credit | Fair Value, Measurements, Recurring | Discounted cash flow | ABL Facility - due April 2022 | Significant Unobservable Inputs (Level 3) | Discount rate
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Debt, measurement input		0.09

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Income tax expense (benefit)	$ 208	$ (45)	$ 211	$ (2,200)
Income (loss) from continuing operations before income taxes	83,901	$ (68,533)	32,623	$ (188,620)
Current estimated federal income tax liability	0		0
Decrease in deferred tax asset valuation allowance			12,701
Tax Year 2016
Income Tax Examination [Line Items]
Refund from carryback claim	64,160		64,160
Accrued interest	$ 5,425		$ 5,425

Employee Benefit Plans - Schedu

Employee Benefit Plans - Schedule of Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost	$ 3,392	$ 4,670	$ 10,176	$ 14,061
Expected return on plan assets	(7,183)	(6,752)	(21,549)	(20,312)
Amortization of net actuarial loss	804	511	2,413	1,501
Settlement	0	0	0	1,230
Net periodic benefit	(2,987)	(1,571)	(8,960)	(3,520)
Black Lung
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	739	499	2,217	1,479
Interest cost	607	678	1,821	2,275
Expected return on plan assets	(14)	(13)	(42)	(40)
Amortization of net actuarial loss	522	426	1,566	927
Net periodic benefit	$ 1,854	$ 1,590	$ 5,562	$ 4,641

Employee Benefit Plans - Narrat

Employee Benefit Plans - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Jun. 30, 2021	Sep. 30, 2021
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Decrease in liability for pension obligations	$ 8,838
Pension | American Rescue Plan Act
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Pension plan, employer contributions		$ 6,571

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details) T in Thousands, $ in Thousands	3 Months Ended		9 Months Ended	12 Months Ended
	Dec. 31, 2021USD ($)T	Sep. 30, 2021USD ($)T	Sep. 30, 2021USD ($)T	Dec. 31, 2022USD ($)T	Dec. 31, 2020USD ($)	Feb. 21, 2020USD ($)	Feb. 20, 2020USD ($)
Black Lung
Long-term Purchase Commitment [Line Items]
Collateral for self insurance black lunch obligations						$ 65,700	$ 2,600
Surety Bond
Long-term Purchase Commitment [Line Items]
Guarantees		$ 176,909	$ 176,909
Guarantor obligations attributable to discontinued operations		30	30
Reclamation-related obligations
Long-term Purchase Commitment [Line Items]
Collateral supporting guarantees		37,164	37,164
Revolving Credit Facility | Line of Credit | ABL Facility - due April 2022
Long-term Purchase Commitment [Line Items]
Letters of credit outstanding		120,037	120,037		$ 123,108
Revolving Credit Facility | Line of Credit | Credit and Security Agreement
Long-term Purchase Commitment [Line Items]
Letters of credit outstanding		$ 613	$ 613
Cumberland Back-to-Back Coal Supply Agreements
Long-term Purchase Commitment [Line Items]
Purchase and sale contingency, mass purchased and sold (in tons) | T		514	1,974
Purchase and sale contingency, mass purchased and sold, amount		$ 19,948	$ 76,501
Cumberland Back-to-Back Coal Supply Agreements | Forecast
Long-term Purchase Commitment [Line Items]
Purchase and sale contingency, mass purchased and sold (in tons) | T	722			2,581
Purchase and sale contingency, mass purchased and sold, amount	$ 28,207			$ 100,619
Commitment of Fixed Priced Tons from Vendors with Historical Performance Resulting in Less Than 20% of Committed Tonnage Being Delivered
Long-term Purchase Commitment [Line Items]
Minimum quantities to be purchased, 2021		3,016	3,016
Coal Purchase Agreements
Long-term Purchase Commitment [Line Items]
Minimum quantities to be purchased, 2021		22,647	22,647
Shipping
Long-term Purchase Commitment [Line Items]
Minimum quantities to be shipped, 2022		$ 14,905	$ 14,905

Commitments and Contingencies_2

Commitments and Contingencies - Schedule of Restricted Cash Deposits (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020
Long-term Purchase Commitment [Line Items]
Total restricted cash	$ 91,643	$ 105,344
Less current portion	(7,642)	(9,311)	$ (7,104)
Long-term restricted cash	84,001	96,033	$ 124,065
Workers' compensation and black lung obligations
Long-term Purchase Commitment [Line Items]
Total restricted cash	66,488	69,725
Reclamation-related obligations
Long-term Purchase Commitment [Line Items]
Total restricted cash	10,580	8,445
Financial payments and other performance obligations
Long-term Purchase Commitment [Line Items]
Total restricted cash	6,933	17,863
Contingent revenue obligation escrow
Long-term Purchase Commitment [Line Items]
Total restricted cash	$ 7,642	$ 9,311

Commitments and Contingencies_3

Commitments and Contingencies - Schedule of Restricted Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Long-term Purchase Commitment [Line Items]
Total restricted investments	$ 28,695	$ 23,768
Restricted investments, trading	28,695	22,498
Restricted investments, held-to-maturity	0	1,270
Workers' compensation and black lung obligations
Long-term Purchase Commitment [Line Items]
Total restricted investments	211	51
Reclamation-related obligations
Long-term Purchase Commitment [Line Items]
Total restricted investments	26,467	22,233
Financial payments and other performance obligations
Long-term Purchase Commitment [Line Items]
Total restricted investments	$ 2,017	$ 1,484

Commitments and Contingencies_4

Commitments and Contingencies - Cash Deposits Held by Third Parties (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Long-term Purchase Commitment [Line Items]
Total deposits	$ 1,401	$ 28,247
Reclamation-related obligations
Long-term Purchase Commitment [Line Items]
Total deposits	117	25,633
Financial payments and other performance obligations
Long-term Purchase Commitment [Line Items]
Total deposits	403	1,596
Other operating agreements
Long-term Purchase Commitment [Line Items]
Total deposits	$ 881	$ 1,018

Segment Information - Schedule

Segment Information - Schedule of Operating Results and Capital Expenditures (Details) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2021USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2021USD ($)mineplantsegment	Sep. 30, 2020USD ($)	Dec. 31, 2020segment
Segment Reporting Information [Line Items]
Number of reportable segments | segment			1		2
Total revenues	$ 648,841	$ 335,592	$ 1,430,369	$ 1,092,336
Depreciation, depletion and amortization	24,519	49,236	80,261	143,921
Amortization of acquired intangibles, net	2,980	2,074	9,402	4,466
Adjusted EBITDA	148,222	12,360	217,023	76,002
Capital expenditures	22,347	23,507	60,386	90,428
Operating Segments | Met
Segment Reporting Information [Line Items]
Total revenues	626,103	295,381	1,363,918	974,674
Depreciation, depletion and amortization	23,181	41,178	75,403	121,679
Amortization of acquired intangibles, net	3,063	2,535	9,749	7,875
Adjusted EBITDA	155,456	17,772	234,824	104,408
Capital expenditures	21,882	22,668	$ 59,408	83,449
Operating Segments | Met | Virginia
Segment Reporting Information [Line Items]
Number of active mines | mine			5
Number of preparation plants | plant			2
Operating Segments | Met | West Virginia
Segment Reporting Information [Line Items]
Number of active mines | mine			13
Number of preparation plants | plant			5
All Other
Segment Reporting Information [Line Items]
Total revenues	22,738	40,211	$ 66,451	117,662
Depreciation, depletion and amortization	1,338	8,058	4,858	22,242
Amortization of acquired intangibles, net	(83)	(461)	(347)	(3,409)
Adjusted EBITDA	(7,234)	(5,412)	(17,801)	(28,406)
Capital expenditures	$ 465	$ 839	$ 978	$ 6,979
All Other | West Virginia
Segment Reporting Information [Line Items]
Number of active mines | mine			1
Number of preparation plants | plant			1

Segment Information - Reconcili

Segment Information - Reconciliation of Net Income (Loss) to Adjusted EBITDA (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting, Other Significant Reconciling Item [Line Items]
Net income (loss) from continuing operations	$ 83,693	$ (68,488)	$ 32,412	$ (186,420)
Interest expense	17,338	18,746	53,290	56,238
Interest income	(54)	(376)	(322)	(6,874)
Income tax expense	208	(45)	211	(2,200)
Depreciation, depletion and amortization	24,519	49,236	80,261	143,921
Non-cash stock compensation expense	1,188	1,078	4,351	4,200
Mark-to-market adjustment for acquisition-related obligations	11,676	3,624	18,009	(13,425)
Accretion on asset retirement obligations	6,674	6,737	19,970	19,945
Asset impairment and restructuring	0	(226)	(561)	53,981
Management restructuring costs				940
Loss on partial settlement of benefit obligations				1,230
Amortization of acquired intangibles, net	2,980	2,074	9,402	4,466
Adjusted EBITDA	148,222	12,360	217,023	76,002
Operating Segments | Met
Segment Reporting, Other Significant Reconciling Item [Line Items]
Net income (loss) from continuing operations	125,750	(29,656)	139,354	(68,338)
Interest expense	49	(188)	132	(1,494)
Interest income	(1)	(2)	(6)	(63)
Income tax expense	0	0	0	0
Depreciation, depletion and amortization	23,181	41,178	75,403	121,679
Non-cash stock compensation expense	6	105	22	410
Mark-to-market adjustment for acquisition-related obligations	0	0	0	0
Accretion on asset retirement obligations	3,408	3,800	10,170	10,887
Asset impairment and restructuring		0	0	32,951
Management restructuring costs				501
Loss on partial settlement of benefit obligations				0
Amortization of acquired intangibles, net	3,063	2,535	9,749	7,875
Adjusted EBITDA	155,456	17,772	234,824	104,408
All Other
Segment Reporting, Other Significant Reconciling Item [Line Items]
Net income (loss) from continuing operations	(42,057)	(38,832)	(106,942)	(118,082)
Interest expense	17,289	18,934	53,158	57,732
Interest income	(53)	(374)	(316)	(6,811)
Income tax expense	208	(45)	211	(2,200)
Depreciation, depletion and amortization	1,338	8,058	4,858	22,242
Non-cash stock compensation expense	1,182	973	4,329	3,790
Mark-to-market adjustment for acquisition-related obligations	11,676	3,624	18,009	(13,425)
Accretion on asset retirement obligations	3,266	2,937	9,800	9,058
Asset impairment and restructuring		(226)	(561)	21,030
Management restructuring costs				439
Loss on partial settlement of benefit obligations				1,230
Amortization of acquired intangibles, net	(83)	(461)	(347)	(3,409)
Adjusted EBITDA	$ (7,234)	$ (5,412)	$ (17,801)	$ (28,406)

Segment Information - Revenue f

Segment Information - Revenue from External Customers (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenues from External Customers and Long-Lived Assets [Line Items]
Coal revenues	$ 647,129	$ 335,189	$ 1,426,039	$ 1,089,764
Non-US
Revenues from External Customers and Long-Lived Assets [Line Items]
Coal revenues	$ 516,877	$ 205,576	$ 1,016,677	$ 697,692
Non-US | Geographic Concentration Risk | Export Coal Revenue
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk percentage	80.00%	61.00%	71.00%	64.00%

Uncategorized Items - amr-20210

Label	Element	Value
Accounting Standards Update [Extensible Enumeration]	us-gaap_AccountingStandardsUpdateExtensibleList	Accounting Standards Update 2016-13 [Member]