Arq (ARQ) 10-Q 8 Nov 23 2023 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2023	Nov. 02, 2023
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2023
Document Transition Report	false
Entity File Number	001-37822
Entity Registrant Name	Advanced Emissions Solutions, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	27-5472457
Entity Address, Address Line One	8051 E. Maplewood Ave
Entity Address, Address Line Two	Suite 210
Entity Address, City or Town	Greenwood Village
Entity Address, State or Province	CO
Entity Address, Postal Zip Code	80111
City Area Code	720
Local Phone Number	598-3500
Title of 12(b) Security	Common stock, par value $0.001 per share
Trading Symbol	ADES
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		33,180,907
Entity Central Index Key	0001515156
Current Fiscal Year End Date	--12-31
Amendment Flag	false
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q3

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Current assets:
Cash	$ 52,529	$ 66,432
Receivables, net	14,225	13,864
Inventories, net	18,549	17,828
Prepaid expenses and other current assets	6,171	7,538
Total current assets	91,474	105,662
Restricted cash, long-term	8,792	10,000
Property, plant and equipment, net of accumulated depreciation of $17,110 and $11,897, respectively	85,709	34,855
Other long-term assets, net	44,629	30,647
Total Assets	230,604	181,164
Current liabilities:
Accounts payable and accrued expenses	13,972	16,108
Current portion of debt obligations	1,991	1,131
Other current liabilities	6,061	6,645
Total current liabilities	22,024	23,884
Long-term debt obligations, net of current portion	19,179	3,450
Other long-term liabilities	15,107	13,851
Total Liabilities	56,310	41,185
Commitments and contingencies (Note 8)
Stockholders’ equity:
Preferred stock: par value of $0.001 per share, 50,000,000 shares authorized including Series A Convertible Preferred Stock: par value $0.001 per share, 8,900,000 shares authorized, none issued and outstanding	0	0
Common stock: par value of $0.001 per share, 100,000,000 shares authorized, 37,799,053 and 23,788,319 shares issued, and 33,180,907 and 19,170,173 shares outstanding at September 30, 2023 and December 31, 2022, respectively	38	24
Treasury stock, at cost: 4,618,146 and 4,618,146 shares as of September 30, 2023 and December 31, 2022, respectively	(47,692)	(47,692)
Additional paid-in capital	153,695	103,698
Retained earnings	68,253	83,949
Total Stockholders’ Equity	174,294	139,979
Total Liabilities and Stockholders’ Equity	$ 230,604	$ 181,164

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2023	Feb. 01, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Accumulated depreciation	$ 17,110		$ 11,897
Preferred stock par value (in dollars per share)	$ 0.001		$ 0.001
Preferred stock, shares authorized (in shares)	50,000,000		50,000,000
Temporary equity, par value (in dollars per share)	$ 0.001	$ 0.001	$ 0.001
Temporary equity, shares authorized (in shares)	8,900,000		8,900,000
Temporary equity, shares issued (in shares)	0		0
Temporary equity, shares outstanding (in shares)	0		0
Preferred stock, shares issued (in shares)	0		0
Preferred stock, shares outstanding (in shares)	0		0
Common stock par value (in dollars per share)	$ 0.001	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	100,000,000		100,000,000
Common stock, shares issued (in shares)	37,799,053		23,788,319
Common stock, shares outstanding (in shares)	33,180,907		19,170,173
Treasury stock (in shares)	4,618,146		4,618,146

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Revenues:
Revenue from Contract with Customer, Product and Service [Extensible Enumeration]	Product [Member]	Product [Member]	Product [Member]	Product [Member]
Total revenues	$ 29,829	$ 28,437	$ 71,079	$ 79,578
Operating expenses:
Consumables cost of revenue, exclusive of depreciation and amortization	20,707	21,575	53,218	62,992
Payroll and benefits	4,228	2,313	12,482	7,458
Legal and professional fees	1,654	3,668	8,060	7,395
General and administrative	3,054	1,833	9,177	5,662
Depreciation, amortization, depletion and accretion	2,711	1,671	7,276	4,765
Gain on sale of Marshall Mine, LLC	0	0	(2,695)	0
Total operating expenses	32,354	31,060	87,518	88,272
Operating loss	(2,525)	(2,623)	(16,439)	(8,694)
Other income (expense):
Earnings from equity method investments	412	0	1,512	3,222
Interest expense	(787)	(83)	(2,155)	(259)
Other	725	315	1,510	(19)
Total other income	350	232	867	2,944
Loss before income taxes	(2,175)	(2,391)	(15,572)	(5,750)
Income tax benefit	0	0	33	0
Net loss	$ (2,175)	$ (2,391)	$ (15,539)	$ (5,750)
Loss per common share (Note 1):
Basic (in dollars per share)	$ (0.07)	$ (0.13)	$ (0.56)	$ (0.31)
Diluted (in dollars per share)	$ (0.07)	$ (0.13)	$ (0.56)	$ (0.31)
Weighted-average number of common shares outstanding:
Basic (in shares)	31,807	18,487	27,894	18,435
Diluted (in shares)	31,807	18,487	27,894	18,435

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid-in Capital	Retained Earnings
Beginning balance (in shares) at Dec. 31, 2021		23,460,212
Beginning balance at Dec. 31, 2021	$ 147,301	$ 23	$ (47,692)	$ 102,106	$ 92,864
Beginning balance (in shares) at Dec. 31, 2021			(4,618,146)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation (in shares)		323,742
Stock-based compensation	464	$ 1		463
Repurchase of common shares to satisfy minimum tax withholdings (in shares)		(59,736)
Repurchase of common shares to satisfy minimum tax withholdings	(382)			(382)
Net loss	(3,033)				(3,033)
Ending balance (in shares) at Mar. 31, 2022		23,724,218
Ending balance at Mar. 31, 2022	144,350	$ 24	$ (47,692)	102,187	89,831
Ending balance (in shares) at Mar. 31, 2022			(4,618,146)
Beginning balance (in shares) at Dec. 31, 2021		23,460,212
Beginning balance at Dec. 31, 2021	147,301	$ 23	$ (47,692)	102,106	92,864
Beginning balance (in shares) at Dec. 31, 2021			(4,618,146)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(5,750)
Ending balance (in shares) at Sep. 30, 2022		23,730,499
Ending balance at Sep. 30, 2022	142,623	$ 24	$ (47,692)	103,175	87,116
Ending balance (in shares) at Sep. 30, 2022			(4,618,146)
Beginning balance (in shares) at Mar. 31, 2022		23,724,218
Beginning balance at Mar. 31, 2022	144,350	$ 24	$ (47,692)	102,187	89,831
Beginning balance (in shares) at Mar. 31, 2022			(4,618,146)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation (in shares)		(30,459)
Stock-based compensation	484			484
Repurchase of common shares to satisfy minimum tax withholdings (in shares)		(551)
Repurchase of common shares to satisfy minimum tax withholdings	(3)			(3)
Net loss	(326)				(326)
Ending balance (in shares) at Jun. 30, 2022		23,693,208
Ending balance at Jun. 30, 2022	144,505	$ 24	$ (47,692)	102,668	89,505
Ending balance (in shares) at Jun. 30, 2022			(4,618,146)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation (in shares)		37,291
Stock-based compensation	507			507
Net loss	(2,391)
Cash dividends canceled on common stock	2				2
Ending balance (in shares) at Sep. 30, 2022		23,730,499
Ending balance at Sep. 30, 2022	142,623	$ 24	$ (47,692)	103,175	87,116
Ending balance (in shares) at Sep. 30, 2022			(4,618,146)
Beginning balance (in shares) at Dec. 31, 2022		23,788,319
Beginning balance at Dec. 31, 2022	$ 139,979	$ 24	$ (47,692)	103,698	83,949
Beginning balance (in shares) at Dec. 31, 2022	(4,618,146)		(4,618,146)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation (in shares)		483,242
Stock-based compensation	$ 563			563
Issuance of common stock pursuant to Arq Acquisition, net of offering costs (in shares)		3,814,864
Issuance of common stock pursuant to Arq Acquisition, net of offering costs	12,437	$ 4		12,433
Issuance of common stock related to PIPE Investment, net of offering costs (in shares)		3,842,315
Issuance of common stock related to PIPE Investment, net of offering costs	15,220	$ 4		15,216
Issuance of warrant	826			826
Repurchase of common shares to satisfy minimum tax withholdings (in shares)		(74,104)
Repurchase of common shares to satisfy minimum tax withholdings	(146)			(146)
Preferred stock dividends declared on redeemable preferred stock	(157)				(157)
Net loss	(7,508)				(7,508)
Ending balance (in shares) at Mar. 31, 2023		31,854,636
Ending balance at Mar. 31, 2023	161,214	$ 32	$ (47,692)	132,590	76,284
Ending balance (in shares) at Mar. 31, 2023			(4,618,146)
Beginning balance (in shares) at Dec. 31, 2022		23,788,319
Beginning balance at Dec. 31, 2022	$ 139,979	$ 24	$ (47,692)	103,698	83,949
Beginning balance (in shares) at Dec. 31, 2022	(4,618,146)		(4,618,146)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ (15,539)
Ending balance (in shares) at Sep. 30, 2023		37,799,053
Ending balance at Sep. 30, 2023	$ 174,294	$ 38	$ (47,692)	153,695	68,253
Ending balance (in shares) at Sep. 30, 2023	(4,618,146)		(4,618,146)
Beginning balance (in shares) at Mar. 31, 2023		31,854,636
Beginning balance at Mar. 31, 2023	$ 161,214	$ 32	$ (47,692)	132,590	76,284
Beginning balance (in shares) at Mar. 31, 2023			(4,618,146)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation (in shares)		(16,430)
Stock-based compensation	545			545
Repurchase of common shares to satisfy minimum tax withholdings (in shares)		(6,973)
Repurchase of common shares to satisfy minimum tax withholdings	(14)			(14)
Net loss	(5,856)				(5,856)
Issuance of common stock upon conversion of preferred stock (in shares)		5,362,926
Issuance of common stock upon conversion of preferred stock	18,926	$ 5		18,921
Ending balance (in shares) at Jun. 30, 2023		37,194,159
Ending balance at Jun. 30, 2023	174,815	$ 37	$ (47,692)	152,042	70,428
Ending balance (in shares) at Jun. 30, 2023			(4,618,146)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation (in shares)		105,244
Stock-based compensation	702			702
Repurchase of common shares to satisfy minimum tax withholdings (in shares)		(28,129)
Repurchase of common shares to satisfy minimum tax withholdings	(48)			(48)
Net loss	(2,175)				(2,175)
Issuance of common stock to related party (in shares)		527,779
Issuance of common stock to related party	1,000	$ 1		999
Ending balance (in shares) at Sep. 30, 2023		37,799,053
Ending balance at Sep. 30, 2023	$ 174,294	$ 38	$ (47,692)	$ 153,695	$ 68,253
Ending balance (in shares) at Sep. 30, 2023	(4,618,146)		(4,618,146)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Cash flows from operating activities
Net loss	$ (15,539)	$ (5,750)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Depreciation, amortization, depletion and accretion	7,276	4,765
Gain on sale of Marshall Mine, LLC	(2,695)	0
Operating lease expense	2,061	1,953
Stock-based compensation expense	1,810	1,455
Earnings from equity method investments	(1,512)	(3,222)
Amortization of debt discount and debt issuance costs	395	0
Other non-cash items, net	0	438
Changes in operating assets and liabilities:
Receivables and related party receivables	(359)	1,199
Prepaid expenses and other assets	3,595	(991)
Inventories, net	(811)	(7,222)
Other long-term assets, net	(3,646)	2,136
Accounts payable and accrued expenses	(12,033)	1,827
Other current liabilities	148	(184)
Operating lease liabilities	(140)	1,445
Other long-term liabilities	305	206
Distributions from equity method investees, return on investment	0	2,297
Net cash (used in) provided by operating activities	(21,145)	352
Cash flows from investing activities
Acquisition of property, plant, equipment, and intangible assets, net	(17,008)	(6,178)
Cash and restricted cash acquired in business acquisition	2,225	0
Payment for disposal of Marshall Mine, LLC	(2,177)	0
Acquisition of mine development costs	(1,856)	(345)
Distributions from equity method investees in excess of cumulative earnings	1,512	3,316
Proceeds from sale of property and equipment	0	1,241
Net cash used in investing activities	(17,304)	(1,966)
Cash flows from financing activities
Net proceeds from Term Loan, related party, net of discount and issuance costs	8,522	0
Principal payments on finance lease obligations	(855)	(913)
Principal payments on Arq Loan	(341)	0
Repurchase of common stock to satisfy tax withholdings	(208)	(385)
Dividends paid on common stock	0	(45)
Net cash provided by (used) in financing activities	23,338	(1,343)
Decrease in Cash and Restricted Cash	(15,111)	(2,957)
Cash and Restricted Cash, beginning of period	76,432	88,780
Cash and Restricted Cash, end of period	61,321	85,823
Supplemental disclosure of non-cash investing and financing activities:
Equity issued as consideration for acquisition of business	31,206	0
Change in accrued purchases for property and equipment	255	339
Paid-in-kind dividend on Series A Preferred Stock	157	0
Acquisition of property and equipment under finance lease	0	1,641
Nonrelated Party
Cash flows from financing activities
Net proceeds from common stock	15,220	0
Related Party
Cash flows from financing activities
Net proceeds from common stock	$ 1,000	$ 0

Organization and Basis of Prese

Organization and Basis of Presentation	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Organization and Basis of Presentation	Organization and Basis of Presentation Advanced Emissions Solutions, Inc. ("ADES" or the "Company") is a Delaware corporation with its principal office located in Greenwood Village, Colorado, manufacturing and logistics operations located in Louisiana and a manufacturing facility located in Kentucky. The Company is an environmental technology company and has been principally engaged in the sale of consumable air and water treatment solutions including activated carbon ("AC") and chemical technologies. The Company's proprietary technologies in the advanced purification technologies ("APT") market enable customers to reduce air and water contaminants, including mercury and other pollutants, to maximize utilization levels and to improve operating efficiencies to meet the challenges of existing and pending air quality and water regulations. The Company manufactures and sells AC and other chemicals used to capture and remove contaminants for coal-fired power generation and for industrial, municipal and remediation water treatment markets. The Company also owns an associated lignite mine ("Five Forks Mine") that currently supplies the primary raw material for manufacturing AC. Basis of Presentation The accompanying Condensed Consolidated Financial Statements of ADES are unaudited and have been prepared in conformity with accounting principles generally accepted in the United States ("U.S. GAAP") and with Article 10 of Regulation S-X of the Securities and Exchange Commission. In compliance with those instructions, certain information and footnote disclosures normally included in annual consolidated financial statements prepared in accordance with U.S. GAAP have been condensed or omitted. The unaudited Condensed Consolidated Financial Statements of ADES in this quarterly report ("Quarterly Report") are presented on a consolidated basis and include ADES and its wholly-owned subsidiaries (collectively, the "Company"). Also included within the unaudited Condensed Consolidated Financial Statements are the Company's unconsolidated equity investments, Tinuum Group and Tinuum Services, which are accounted for under the equity method of accounting, and Highview Enterprises Limited (the "Highview Investment"), which is accounted for in accordance with U.S. GAAP applicable to equity investments that do not qualify for the equity method of accounting. Results of operations and cash flows for the interim periods are not necessarily indicative of the results that may be expected for the entire year. All significant intercompany transactions and accounts were eliminated in consolidation for all periods presented in this Quarterly Report. In the opinion of management, these Condensed Consolidated Financial Statements include all normal and recurring adjustments considered necessary for a fair presentation of the results of operations, financial position, stockholders' equity and cash flows for the interim periods presented. These Condensed Consolidated Financial Statements should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2022 (the "2022 Form 10-K"). Significant accounting policies disclosed therein have not changed. Earnings (Loss) Per Share Basic earnings (loss) per share is computed using the weighted-average number of shares of common stock outstanding during the reporting period. Diluted earnings (loss) per share is computed in a manner consistent with that of basic earnings per share, while considering other potentially dilutive securities. For the three and nine months ended September 30, 2023 and 2022, potentially dilutive securities consist of unvested restricted stock awards ("RSAs"), stock options and contingent performance stock units ("PSUs"). The following table sets forth the calculations of basic and diluted loss per share: Three Months Ended September 30, Nine Months Ended September 30, (in thousands, except per share amounts) 2023 2022 2023 2022 Net loss $ (2,175) $ (2,391) $ (15,539) $ (5,750) Less: Dividends declared on redeemable preferred stock — — 157 — Loss attributable to common stockholders $ (2,175) $ (2,391) $ (15,696) $ (5,750) Basic weighted-average common shares outstanding 31,807 18,487 27,894 18,435 Add: dilutive effect of equity instruments — — — — Diluted weighted-average shares outstanding 31,807 18,487 27,894 18,435 Loss per share - basic $ (0.07) $ (0.13) $ (0.56) $ (0.31) Loss per share - diluted $ (0.07) $ (0.13) $ (0.56) $ (0.31) For the three and nine months ended September 30, 2023 and 2022, potentially dilutive securities of 2.3 million and 0.8 million and 1.4 million and 0.7 million shares of common stock, respectively, are outstanding but are not included in the calculation of diluted net loss per share because the effect would be anti-dilutive. Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. There have been no changes in the Company's critical accounting estimates from those that were disclosed in the 2022 Form 10-K. Actual results could differ from these estimates. Risks and Uncertainties The Company is principally dependent on the operations of its APT business and its cash on hand to provide liquidity over the near and long term. The Company's revenues, sales volumes, earnings and cash flows are significantly affected by prices of competing power generation sources such as natural gas and renewable energy. During periods of low natural gas prices, natural gas provides a competitive alternative to coal-fired power generation and therefore, coal consumption for purposes of power generation may be reduced, which in turn reduces the demand for the Company's products. However, during periods of higher prices for competing power generation sources, there is an increase in coal consumption and thus demand for the Company's products also increases. In addition, coal consumption for purposes of power generation and demand for the Company's products are affected by the demand for electricity, which is higher in the warmer and colder months of the year. As a result, the Company's interim period results are subject to seasonal variations whereby its revenues and cost of revenues tend to be higher in its first and third fiscal quarters compared to its second and fourth fiscal quarters. Abnormal temperatures during the summer and winter months may significantly affect coal consumption and impurities within various municipalities' water sources, and thus impact the demand for the Company's products. As of September 30, 2023, the Company holds cash at two financial institutions that exceed the Federal Deposit Insurance Corporation ("FDIC") limits (currently $250 thousand). If a financial institution was unable to perform its obligations, the Company would be at risk regarding the amount of cash held in excess of the FDIC limits. Concentration of credit risk The Company is exposed to concentrations of credit risk primarily related to its customer accounts receivable. The Company regularly monitors its credit risk to mitigate the possibility of current and future exposures resulting in a loss. Historically, the losses related to credit risk have been immaterial. The Company evaluates the creditworthiness of its customers prior to entering into agreements to sell its products and, as necessary, throughout the life of the customer relationship. Reclassifications Certain balances have been reclassified from the prior year to conform to the current year presentation. Such reclassifications had no effect on the Company’s results of operations or financial position in any of the periods presented.

Arq Acquisition

Arq Acquisition	9 Months Ended
	Sep. 30, 2023
Business Combination and Asset Acquisition [Abstract]
Arq Acquisition	Arq Acquisition On February 1, 2023 (the "Acquisition Date"), the Company entered into a Securities Purchase Agreement (the "Purchase Agreement") with Arq Limited ("Arq Ltd."), a company incorporated under the laws of Jersey, pursuant to which the Company acquired all of the direct and indirect equity interests of Arq Ltd.'s subsidiaries (the "Arq Acquisition," and hereafter referred to as "Arq") in exchange for consideration (the "Purchase Consideration") totaling $31.2 million, and consisting of (i) 3,814,864 shares of the Company's common stock, par value $0.001 per share (the "Common Stock") and (ii) 5,294,462 preferred shares (the "Preferred Shares") of the Company's Series A Convertible Preferred Stock, par value $0.001 per share (the "Series A Preferred Stock"). Arq's principal office is located in Corbin, Kentucky near its production facility ("the Corbin Facility"). The Corbin location consists of bituminous coal reserves and a manufacturing facility used to recover and purify the bituminous coal fines for sale or further conversion to value-added specialty chemicals. Arq is a pre-revenue, environmental technology company that has developed a process for transforming coal waste into a purified, microfine carbon powder, known as Arq powder TM ("Arq Powder"). The Company expects to begin using Arq Powder to produce granular activated carbon products in the second half of 2024. The Company accounted for the Arq Acquisition as an acquisition of a business. The total Purchase Consideration was $31.2 million and was allocated to the acquired assets and assumed liabilities of Arq based on their estimated fair values as of the Acquisition Date. The Purchase Consideration was comprised of the fair values as of the Acquisition Date of 3,814,864 shares of Common Stock, valued at $12.4 million, and 5,294,462 Preferred Shares, valued at $18.8 million. The Company also incurred $8.7 million in acquisition-related costs, which were expensed as incurred and included in the "General and administrative" and "Legal and professional fees" line items in the Statements of Operations. The following table provides the final purchase price allocation to the assets acquired and liabilities assumed as of the Acquisition Date: (in thousands) Purchase Price Allocation Fair value of assets acquired: Cash $ 1,411 Prepaid expenses and other current assets 2,229 Restricted cash, long-term 814 Property, plant and equipment, net 39,159 Other long-term assets, net 11,717 Amount attributable to assets acquired 55,330 Fair Value of liabilities assumed: Accounts payable and accrued expenses 9,806 Current portion of long-term debt 494 Other current liabilities 103 Long-term debt, net of current portion 9,199 Other long-term liabilities 4,523 Amount attributable to liabilities assumed 24,125 Net assets acquired $ 31,205 The following represents the intangible asset identified as part of the Arq Acquisition and which is included in "Other long-term-assets, net" in the table above: (in thousands) Amount Weighted Average Useful Life (years) Developed technology $ 7,700 20 Series A Preferred Stock In connection with the issuance of the Series A Preferred Stock pursuant to the Purchase Agreement, the Company filed the Certificate of Designations of Preferred Stock for the Series A Preferred Stock (the "Certificate of Designations") with the Secretary of State of the State of Delaware. Under the Certificate of Designations, 8.9 million preferred shares were designated as Series A Preferred Stock. On June 13, 2023 (the "Conversion Date"), the Company's stockholders approved the conversion of all of the outstanding shares of Series A Preferred Stock, including the "Escrow Shares," as defined below, and the corresponding issuance of shares of Common Stock. Upon such approval, each outstanding share of Series A Preferred Stock was automatically converted into the number of shares of Common Stock described below. Each share of Series A Preferred Stock was deemed to have an original issue price of $4.00 per share (the "Original Issue Amount"). The number of shares of Common Stock issued upon conversion of each share of Series A Preferred Stock was equal to the product of (i) the sum of (A) the Original Issue Amount plus (B) an amount equal to the cumulative amount of the accrued and unpaid dividends on such share at such time divided by (ii) the Original Issue Amount, subject to adjustment. Holders of the Series A Preferred Stock were entitled to receive cumulative dividends, which accrued quarterly on the last day of each applicable quarter (whether or not declared or funds for their payment are lawfully available) and were payable quarterly, in arrears, on the earlier to occur of (a) the date any dividend is paid to holders of Common Stock with respect to such quarter and (b) 30 days after the end of each quarter (the "Series A Quarterly Dividend") at the rate per share of Series A Preferred Stock equal to the greater of (i) if the Company declared a cash dividend on the Common Stock with respect to such quarter, the amount of the cash dividend that would be received by a holder of Common Stock in which such share of Series A Preferred Stock would be convertible on the record date for such cash dividend and (ii) an annual rate (the "Rate") of 8.0% of the Original Issue Amount compounded quarterly with respect to such quarter. On March 31, 2023, the Company declared a dividend of 68,464 Series A PIK Shares with respect to the accrued dividends on the Preferred Shares for the first quarter of 2023 (the "First Quarter PIK Dividend"). The First Quarter PIK Dividend was recorded at the estimated fair value of $0.2 million as of March 31, 2023 and was paid on April 21, 2023. Under the terms of the Purchase Agreement, a total of 833,914 Preferred Shares, were held in escrow (the "Preferred Escrow Shares") based on a contingent redemption feature, (the "Contingent Redemption Feature," as defined below). The fair value of the Preferred Shares issued was determined to be $3.46 per Preferred Share on the Acquisition Date (the "Preferred Share Price") plus the value of the Contingent Redemption Feature related to the Escrow Shares. The Escrow Shares were converted into shares of Common Stock on the Conversion Date and continue to be held in escrow (the "Escrow Common Shares"). The Escrow Common Shares are being withheld pending a determination by the IRS that no tax withholding is required on the Purchase Consideration issued to Arq Ltd. (the "Arq Ltd. Tax Liability"). The Company estimated the fair value of the potential Arq Ltd. Tax Liability at $3.3 million. In the event that the IRS determines that no withholding is required by Arq Ltd. in connection with the Purchase Consideration received by Arq Ltd., all of the Escrow Common Shares will be released and delivered to Arq Ltd. In the event that the IRS determines that any amount of withholding is required by Arq Ltd., the Company has agreed to redeem a sufficient number of Escrow Common Shares to fund the required payment to the IRS, and that number of Escrow Common Shares will be returned to the Company. The number of Escrow Common Shares to be returned to the Company is equal to the required withholding amount divided by the Original Issue Amount, not to exceed a maximum of 833,914 Escrow Common Shares, and is equal to $3.3 million based on the Original Issue Amount (the "Maximum Contingent Redemption Amount"). The fair value of the Preferred Escrow Shares was determined on the Acquisition Date and was comprised of the Maximum Contingent Redemption Amount and the fair value of the non-escrowed Preferred Shares ("Non-Preferred Escrow Shares"). The Series A Preferred Stock contained a mandatory redemption feature in the event the Preferred Shares, including future issuances of Series A Preferred Stock issued under dividend requirements, were not converted into shares of Common Stock prior to February 1, 2028. The Company concluded that both the Escrow Shares and the Non Escrow Shares did not meet the definition of mandatorily redeemable financial instruments as there was not a substantive conversion feature, and were therefore not classified as liabilities. As both the Escrow Shares and Non Escrow Shares represented financial instruments that were redeemable for cash, SEC guidance mandates that preferred securities which are redeemable upon the occurrence of an event that is not solely within the control of the issuer be classified outside of permanent equity as "temporary equity." Accordingly, the Company classified and reported the Series A Preferred Stock as temporary equity and in the Consolidated Balance Sheet as of as of March 31, 2023. On the Conversion Date, all shares of Series A Preferred Stock were converted into 5,362,926 shares of Common Stock, and the Company reclassified all of the Series A Preferred Stock to Common Stock as of June 30, 2023. Other The amounts of year to date revenues and net loss for Arq for the period from the Acquisition Date to September 30, 2023 are as follows: Nine Months Ended September 30, (in thousands) 2023 Revenues $ — Net loss $ (9,199) The following represents the pro forma effects of the Arq Acquisition as if it had occurred on January 1, 2022. The pro forma net loss for each of the two periods presented has been calculated after applying the Company’s accounting policies in effect for those periods. In addition, pro forma net loss includes: (1) for the nine months ended September 30, 2022, an increase in Payroll and benefits for compensation expense of $1.9 million payable to certain Arq employees, triggered by change in control provisions in employment agreements and employee severance agreements that has not been recognized in the historical financial statements, assuming such amounts will be paid in cash; (2) for the nine months ended September 30, 2023 and 2022, a decrease in depreciation and amortization of $0.2 million and $1.2 million, respectively, resulting from fair value adjustments to Property, plant, equipment; (3) for the nine months ended September 30, 2023 and 2022, an increase in amortization of $0.1 million and $0.3 million, respectively, resulting from fair value adjustments to intangible assets; (4) for the nine months ended September 30, 2023 and 2022, increases to Interest expense of $0.2 million and $1.4 million, respectively, for: (a) the issuance of the Term Loan (as defined below) including stated interest and the amortization of the Term Loan's discount and issuance costs and (b) amortization of debt discount related to a fair value adjustment to an assumed term loan of Arq; and (5) the removal of $3.8 million of transaction costs incurred for the period from October 1, 2022 to September 30, 2023 but included as additional transaction costs for the nine months ended September 30, 2022, together with the income tax effects on (1) through (5). Since Arq had no revenues for the nine months ended September 30, 2023 or 2022, pro forma revenues are the same as the Company's reported revenues for those periods. Nine Months Ended September 30, (in thousands) 2023 2022 Revenues $ 71,079 $ 79,578 Net loss $ (12,100) $ (53,752)

Marshall Mine

Marshall Mine	9 Months Ended
	Sep. 30, 2023
Business Combination and Asset Acquisition [Abstract]
Marshall Mine	Marshall MineOn March 27, 2023, (the "MM Closing Date"), the Company completed the sale of all of its membership interests in Marshall Mine, LLC to a third party (the "Buyer") in exchange for cash payment of $2.2 million (the "MM Purchase Price") made by the Company to the Buyer and the assumption by the Buyer of certain liabilities of Marshall Mine, LLC. As of the MM Closing Date, Marshall Mine, LLC had outstanding liabilities of approximately $4.9 million that were discharged upon payment of the MM Purchase Price by the Company, and the Company recognized a gain of approximately $2.7 million in the Statement of Operations for the nine months ended September 30, 2023.

Revenues

Revenues	9 Months Ended
	Sep. 30, 2023
Revenue from Contract with Customer [Abstract]
Revenues	Revenues Trade receivables represent an unconditional right to consideration in exchange for goods or services transferred to a customer. The Company invoices its customers in accordance with the terms of the contract. Credit terms are generally net 30 - 45 days from the date of invoice. The timing between the satisfaction of performance obligations and when payment is due from the customer is generally not significant. Contract liabilities are comprised of deferred revenue, which represents an obligation to transfer goods or services to a customer for which the Company has received consideration from the customer and, if deliverable within one year or less, is included in "Other current liabilities" in the Condensed Consolidated Balance Sheets and, if deliverable outside of one year, is included in "Other long-term liabilities" in the Condensed Consolidated Balance Sheets. The following table shows the components of the Company's Receivables, net: As of (in thousands) September 30, 2023 December 31, 2022 Trade receivables, net $ 14,138 $ 13,789 Other receivables 87 75 Receivables, net $ 14,225 $ 13,864 For the three and nine months ended September 30, 2023 and 2022, all material performance obligations related to revenues recognized were satisfied at a point in time. For the three and nine months ended September 30, 2023, approximately 7% and 8% , respectively, of Consumables revenues were generated in Canada, and all other revenues were generated in the U.S. For the three and nine months ended September 30, 2022, approximately 7% and 9% respectively, of Consumables revenues were generated in Canada, and all other revenues were generated in the U.S.

Inventories, net

Inventories, net	9 Months Ended
	Sep. 30, 2023
Inventory Disclosure [Abstract]
Inventories, net	Inventories, net The following table summarizes the Company's inventories recorded at the lower of average cost or net realizable value, as of September 30, 2023 and December 31, 2022: As of (in thousands) September 30, 2023 December 31, 2022 Product inventory, net $ 8,659 $ 9,479 Raw material inventory 9,890 8,349 Total inventories, net $ 18,549 $ 17,828

Debt Obligations

Debt Obligations	9 Months Ended
	Sep. 30, 2023
Debt Disclosure [Abstract]
Debt Obligations	Debt Obligations As of (in thousands) September 30, 2023 December 31, 2022 Term Loan due February 2027, related party $ 10,000 $ — Arq Loan due January 2036 9,659 — Finance lease obligations 3,727 4,581 23,386 4,581 Unamortized debt discounts (880) — Unamortized debt issuance costs (1,336) — 21,170 4,581 Less: Current maturities (1,991) (1,131) Total long-term debt obligations $ 19,179 $ 3,450 Term Loan As required under the Purchase Agreement, and on February 1, 2023 (the "Closing Date"), the Company, as borrower, certain of its subsidiaries, as guarantors, and CF Global ("CFG"), a related party, as administrative agent and lender (the "Lender"), entered into a term loan (the "Term Loan") in the amount of $10.0 million, less original issue discount ("OID") of $0.2 million, upon execution of a Term Loan and Security Agreement (the "CFG Loan Agreement"). The Company received net cash proceeds of $8.5 million after deducting the OID and debt issuance costs of $1.3 million. The CFG Loan Agreement also required the issuance of a warrant (the "Warrant") to CFG to purchase 325,457 shares of Common Stock (the "Warrant Shares"), which represented 1% of the post-Arq Acquisition and PIPE Investment (as defined below) fully diluted share capital (as defined in the CFG Loan Agreement), at an exercise price of $0.01 per share. The Warrant has a term of 7 years and contains a cashless exercise provision. The Term Loan matures on February 1, 2027 and bears interest at a rate equal to either (a) Adjusted Term SOFR (subject to a 1.00% floor and a cap of 2.00%) plus a margin of 9.00% paid in cash and 5.00% paid in kind or (b) Base Rate plus a margin of 8.00% paid in cash and 5.00% paid in kind, which interest on the Term Loan in each case shall be payable (or capitalized, in the case of in kind interest) quarterly in arrears. The Company may prepay the Term Loan at any time subject to the following prepayment premium: (i) prior to the twelve month anniversary of the Closing Date, the Make-Whole Amount (as defined below), (ii) thereafter but prior to the thirty-six month anniversary of the Closing Date, 2.00% of the outstanding principal amount of the Term Loan being repaid or prepaid or (iii) thereafter until the maturity date, 1.00% of the outstanding principal amount of the Term Loan being repaid or prepaid. The "Make-Whole Amount," with respect to any repayment or prepayment, is (i) an amount equal to all required interest payable (except for currently accrued and unpaid interest) on the aggregate principal amount of the Term Loan subject to such prepayment or repayment from the date of such prepayment or repayment through but excluding the date that is the first anniversary of the Closing Date calculated using an interest rate equal to (x) Adjusted Term SOFR for an interest period of one month in effect on the third U.S. Government Securities Business Day prior to such prepayment or repayment plus (y) 14.00% per annum and assuming all interest was paid in cash, plus (ii) a prepayment premium of 2.00% on the aggregate principal amount of the Term Loan subject to such prepayment or repayment. The Term Loan is secured by substantially all of the assets of the Company and its subsidiaries (including those acquired in the Acquisition, but excluding those pledged as collateral (the "Arq Loan Assets") under the Arq Loan, as defined and described below), subject to customary exceptions. The CFG Loan Agreement includes, among others, the following covenants: (1) beginning with the first fiscal quarter after March 31, 2023 and as of the end of each fiscal quarter thereafter, the Company must maintain a minimum unrestricted cash balance of $5.0 million; (2) (x) as of December 31, 2023, for the fiscal year then ended, the Company must have a minimum annual revenue, on a consolidated basis, of $70.0 million, (y) as of December 31, 2024, for the fiscal year then ended, the Company must have a minimum annual revenue, on a consolidated basis, of $85.0 million and (z) for any fiscal year thereafter, the Company must have a minimum annual revenue, on a consolidated basis, of $100.0 million; (3) (x) as of December 31, 2024, for the fiscal year then ended, the Company must have a minimum Consolidated EBITDA of $3.0 million and (y) for any fiscal year thereafter, the Company must have a minimum Consolidated EBITDA of $16.0 million; and (4) beginning after the fiscal quarter ending September 30, 2023, during an LTV Trigger Period, ADES must not exceed a loan to value ratio of 0.40:1.00 (based on the consolidated total assets of the Company and its subsidiaries, but excluding the Arq Loan Assets). The Company allocated the cash proceeds of the Term Loan to both the Term Loan and the Warrant based on their relative fair values. The amount allocated to the Warrant was recorded as a debt discount and is amortized to interest expense over the term of the Term Loan. The standalone fair value of the Term Loan was based on a comparison of borrowings and associated credit ratings consistent with those of the Company. As the Warrant is exercisable for $0.01 per share, the fair value is deemed to be equal to the fair value of the underlying shares, and accordingly, the fair value of the Warrant was determined as the number of shares issuable from the exercise of the Warrant (based on 1.0% of post-transaction fully diluted share capital, as defined in the Purchase Agreement) multiplied by the closing share price of the Company's common stock on the Acquisition Date. Arq Loan As consideration in the Arq Acquisition, the Company assumed a term loan (the "Arq Loan") held by certain Arq subsidiaries as set out in the Arq Loan (the "Arq Subsidiaries") with a financial institution (the "Bank") in the principal amount of $10.0 million. The Company recorded the Arq Loan on the Acquisition Date at its estimated fair value of $9.7 million, with the difference of $0.3 million between the estimated fair value and the principal amount recorded as a debt discount and recognized as interest expense over the term of the Arq Loan. The Arq Loan was originally entered into on January 27, 2021 and is comprised of two promissory notes (the "Notes"): (1) "Note A" in the principal amount of $8.0 million, which is guaranteed by the U.S. Department of Agriculture; and (2) "Note B" in the principal amount of $2.0 million. The Notes mature on January 27, 2036 and bear interest at 6.0% per annum through January 2026 and at the prime rate plus 2.75% thereafter. Beginning January 27, 2023 and for the balance of the term of the Arq Loan, the Arq Subsidiaries are required to make combined interest and principal payments monthly in the fixed amount of $0.1 million. Interest is computed and payable on the outstanding principal as of the end of the prior month and the balance of the fixed monthly payment amount is applied to the outstanding principal. The Notes carry a prepayment penalty of 3.0% of the outstanding principal if paid prior to January 27, 2024, 2.0% of the outstanding principal if paid prior to January 27, 2025 and 1.0% of the outstanding principal if paid prior to January 27, 2026. Thereafter, the Arq Loan may be prepaid without penalty. On June 2, 2023 (the "Amendment Date"), certain of the Arq Subsidiaries, which included Corbin Project LLC, Arq Projects Holding Company LLC, Arq St. Rose LLC, Arq Corbin LLC and Arq Corbin Land LLC (collectively, the "Borrowers") and the Bank entered into a loan modification agreement (the "Arq Loan Modification Agreement") to the Arq Loan, as amended by that certain letter agreement by and among the Bank and Borrowers dated January 21, 2022, and as otherwise amended, modified and/or extended by the parties from time to time (collectively, the "Arq Loan Agreement"). As consideration for the Bank entering into the Arq Loan Modification Agreement, the Borrowers agreed to pay a fee of $50,000 plus additional fees incurred by the Bank and were required to deposit an additional $0.7 million into a deposit account (the "Interest Reserve Account" as defined in the Arq Loan Agreement), where the Interest Reserve Account is held as collateral by the Bank. The Borrowers may withdraw funds from the Interest Reserve Account beginning one year from the Amendment Date, subject to restrictions as stated in the Arq Loan Modification Agreement. The Arq Loan Modification Agreement clarified and modified certain terms under the Arq Loan Agreement. The principal clarifications and modifications are as follows: • The Borrowers are not entitled to any further disbursements of proceeds under those promissory notes described in the Arq Loan Modification Agreement; • The Bank agreed to waive certain financial delivery requirements for fiscal years 2021 and 2022; • The Bank agreed to waive certain required financial covenants required as of December 31, 2022 and certain required financial covenants as of December 31, 2023; • The Borrowers are required to establish their operating bank accounts with the Bank no later than September 30, 2023; and • The Bank is authorized to amend and/or amend and restate its then-current security instruments to include additional collateral represented by the Borrowers' acquisition of any equipment or other fixed and/or operating assets in which the Bank does not then hold a lien or security interest.

Leases

Leases	9 Months Ended
	Sep. 30, 2023
Leases [Abstract]
Leases	Leases The Company's operating and finance lease right-of-use ("ROU") assets and liabilities as of September 30, 2023 and December 31, 2022 consisted of the following items (in thousands): As of Leases September 30, 2023 December 31, 2022 Operating Leases Operating lease right-of-use assets, net of accumulated amortization (1) $ 10,673 $ 7,734 Operating lease obligations, current $ 2,045 $ 2,724 Long-term operating lease obligations 8,797 5,133 Total operating lease obligation $ 10,842 $ 7,857 Finance Leases Finance lease right-of-use assets, net of accumulated amortization (2) $ 1,904 $ 2,565 Finance lease obligations, current $ 1,477 $ 1,131 Long-term finance lease obligations 2,250 3,450 Total finance lease obligations $ 3,727 $ 4,581 (1) Operating lease ROU assets are reported net of accumulated amortization of $5.1 million and $4.4 million as of September 30, 2023 and December 31, 2022, respectively. (2) Finance lease ROU assets are reported net of accumulated amortization of $2.5 million and $2.0 million as of September 30, 2023 and December 31, 2022, respectively. Operating leases ROU assets under operating leases and operating lease liabilities are included in the " Other long-term assets Other current liabilities Other long-term liabilities Lease expense for operating leases for the three and nine months ended September 30, 2023 was $1.6 million and $4.3 million, respectively, of which $1.2 million and $3.4 million, respectively, is included in the "Consumables - cost of revenue, exclusive of depreciation and amortization" line item, and $0.4 million and $0.9 million, respectively, is included in the "General and administrative" line item in the Condensed Consolidated Statements of Operations for those periods. Lease expense for operating leases for the three and nine months ended September 30, 2022 was $1.2 million and $3.2 million, respectively, of which $1.1 million and $2.9 million, respectively, is included in the "Consumables - cost of revenue, exclusive of depreciation and amortization" line item, and $0.1 million and $0.4 million, respectively, is included in the "General and administrative" line item in the Condensed Consolidated Statements of Operations for those periods. Finance leases ROU assets under finance leases are included in the "Property, plant and equipment" line item in the Condensed Consolidated Balance Sheets as of September 30, 2023 and December 31, 2022. Interest expense related to finance lease obligations and amortization of ROU assets under finance leases are included in the "Interest expense" and "Depreciation, amortization, depletion and accretion" line items, respectively, in the Condensed Consolidated Statements of Operations for the three and nine months ended September 30, 2023 and 2022. Lease financial information as of and for the three and nine months ended September 30, 2023 and 2022 is provided in the following table: Three Months Ended September 30, Nine Months Ended September 30, (in thousands) 2023 2022 2023 2022 Finance lease cost: Amortization of right-of-use assets $ 215 $ 236 $ 661 $ 607 Interest on lease liabilities 59 76 190 240 Operating lease cost 1,000 805 3,017 2,389 Short-term lease cost 481 373 1,132 832 Variable lease cost (1) 81 5 145 12 Total lease cost $ 1,836 $ 1,495 $ 5,145 $ 4,080 Other Information: Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for finance leases $ 190 $ 240 Operating cash flows for operating leases $ 2,087 $ 2,118 Financing cash flows for finance leases $ 855 $ 913 Right-of-use assets obtained in exchange for new finance lease liabilities $ — $ 1,641 Right-of-use assets obtained in exchange for new operating lease liabilities $ 1,947 $ 3,563 Weighted-average remaining lease term - finance leases 2.1 years 2.9 years Weighted-average remaining lease term - operating leases 7.8 years 4.2 years Weighted-average discount rate - finance leases 5.9 % 5.9 % Weighted-average discount rate - operating leases 12.7 % 6.1 % (1) Primarily includes common area maintenance, property taxes and insurance payable to lessors.
Leases	Leases The Company's operating and finance lease right-of-use ("ROU") assets and liabilities as of September 30, 2023 and December 31, 2022 consisted of the following items (in thousands): As of Leases September 30, 2023 December 31, 2022 Operating Leases Operating lease right-of-use assets, net of accumulated amortization (1) $ 10,673 $ 7,734 Operating lease obligations, current $ 2,045 $ 2,724 Long-term operating lease obligations 8,797 5,133 Total operating lease obligation $ 10,842 $ 7,857 Finance Leases Finance lease right-of-use assets, net of accumulated amortization (2) $ 1,904 $ 2,565 Finance lease obligations, current $ 1,477 $ 1,131 Long-term finance lease obligations 2,250 3,450 Total finance lease obligations $ 3,727 $ 4,581 (1) Operating lease ROU assets are reported net of accumulated amortization of $5.1 million and $4.4 million as of September 30, 2023 and December 31, 2022, respectively. (2) Finance lease ROU assets are reported net of accumulated amortization of $2.5 million and $2.0 million as of September 30, 2023 and December 31, 2022, respectively. Operating leases ROU assets under operating leases and operating lease liabilities are included in the " Other long-term assets Other current liabilities Other long-term liabilities Lease expense for operating leases for the three and nine months ended September 30, 2023 was $1.6 million and $4.3 million, respectively, of which $1.2 million and $3.4 million, respectively, is included in the "Consumables - cost of revenue, exclusive of depreciation and amortization" line item, and $0.4 million and $0.9 million, respectively, is included in the "General and administrative" line item in the Condensed Consolidated Statements of Operations for those periods. Lease expense for operating leases for the three and nine months ended September 30, 2022 was $1.2 million and $3.2 million, respectively, of which $1.1 million and $2.9 million, respectively, is included in the "Consumables - cost of revenue, exclusive of depreciation and amortization" line item, and $0.1 million and $0.4 million, respectively, is included in the "General and administrative" line item in the Condensed Consolidated Statements of Operations for those periods. Finance leases ROU assets under finance leases are included in the "Property, plant and equipment" line item in the Condensed Consolidated Balance Sheets as of September 30, 2023 and December 31, 2022. Interest expense related to finance lease obligations and amortization of ROU assets under finance leases are included in the "Interest expense" and "Depreciation, amortization, depletion and accretion" line items, respectively, in the Condensed Consolidated Statements of Operations for the three and nine months ended September 30, 2023 and 2022. Lease financial information as of and for the three and nine months ended September 30, 2023 and 2022 is provided in the following table: Three Months Ended September 30, Nine Months Ended September 30, (in thousands) 2023 2022 2023 2022 Finance lease cost: Amortization of right-of-use assets $ 215 $ 236 $ 661 $ 607 Interest on lease liabilities 59 76 190 240 Operating lease cost 1,000 805 3,017 2,389 Short-term lease cost 481 373 1,132 832 Variable lease cost (1) 81 5 145 12 Total lease cost $ 1,836 $ 1,495 $ 5,145 $ 4,080 Other Information: Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for finance leases $ 190 $ 240 Operating cash flows for operating leases $ 2,087 $ 2,118 Financing cash flows for finance leases $ 855 $ 913 Right-of-use assets obtained in exchange for new finance lease liabilities $ — $ 1,641 Right-of-use assets obtained in exchange for new operating lease liabilities $ 1,947 $ 3,563 Weighted-average remaining lease term - finance leases 2.1 years 2.9 years Weighted-average remaining lease term - operating leases 7.8 years 4.2 years Weighted-average discount rate - finance leases 5.9 % 5.9 % Weighted-average discount rate - operating leases 12.7 % 6.1 % (1) Primarily includes common area maintenance, property taxes and insurance payable to lessors.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Marken Separation Agreement Pursuant to Mr. Marken's termination as CEO of the Company effective July 17, 2023, the Company and Mr. Marken executed a separation agreement under which Mr. Marken will receive the following payments and benefits: (i) the severance payments and benefits set forth in the terms of his employment agreement upon a termination without "cause," (ii) accelerated vesting of 49,715 shares of restricted stock, (iii) continued eligibility for possible vesting of a pro rata target number of 25,941 performance share units ("PSUs") granted in 2021, subject to achievement of applicable performance measures, (iv) continued eligibility for possible vesting of a pro rata target number of 15,988 PSUs granted in 2022, subject to achievement of applicable performance measures, and (v) continued eligibility for possible vesting of a pro rata target number of 19,834 PSUs granted in 2023, subject to achievement of applicable performance measures. As of September 30, 2023, the Company recorded a liability and corresponding charge in the amount of $0.8 million related to (i) and (ii) above. Retention Agreements As of December 31, 2022, the Company had an outstanding liability of $1.4 million (the "Retention Liability"), which was included in the "Other current liabilities" line item in the Condensed Consolidated Balance Sheet, related to retention agreements (the "Retention Agreements") executed between the Company and its executive officers and certain other key employees in May 2021 and amended in May 2022 in order to maintain the Company's business operations while it pursued and executed on its strategic initiatives. The Retention Agreements were approved by the Compensation Committee of the Board of Directors and the Board of Directors (the "Board") in May 2021 and May 2022. In August 2022, the Company paid $1.0 million pursuant to the payment terms of the Retention Agreements and the Retention Liability was paid in full in January 2023. Surety Bonds and Restricted Cash As the owner of the Five Forks Mine, the Company is required to post a surety bond with a regulatory commission related to performance requirements associated with the Five Forks Mine. As of September 30, 2023 and December 31, 2022 , the amount of this surety bond was $7.5 million . The Company leases land adjacent to the Corbin Facility and is required to post surety bonds with a regulatory commission for reclamation. As of September 30, 2023, the amount of these surety bonds was $3.0 million. The Company holds permits for an abandoned mine in West Virginia ("Mine 4") and is required to post a surety bond with a regulatory commission for reclamation. As of September 30, 2023, the amount of this surety bond was $0.7 million. As the owner of the Marshall Mine, the Company was required to post a surety bond with a regulatory commission. As of December 31, 2022, the Company posted a $16.6 million surety bond that was released upon all of the Conditions for closing the MM Transaction being satisfied, which occurred on March 27, 2023. As of September 30, 2023 and December 31, 2022, the Company posted cash collateral of $8.5 million and $10.0 million, respectively, as required by the Company's surety bond providers, which is reported as long-term restricted cash in the Condensed Consolidated Balance Sheets. As of September 30, 2023, the Company holds a deposit of $0.4 million with a third party for collateral as required under a bonding arrangement for Mine 4. This deposit is included in "Other long-term assets, net" in the Condensed Consolidated Balance Sheet as of September 30, 2023. The Company has a customer supply agreement that requires the Company to post a performance bond in an amount equal to the annual contract value of $3.7 million. As of September 30, 2023, the remaining commitment under this customer contract, which expires on December 31, 2023, was approximately $0.4 million. Tinuum Group In addition to those obligations described in Note 10, the Company has certain limited obligations contingent upon future events in connection with the activities of Tinuum Group. The Company, NexGen Refined Coal, LLC ("NexGen") and two entities affiliated with NexGen have provided an affiliate of the Goldman Sachs Group, Inc. with limited guaranties (the "Tinuum Group Party Guaranties") related to certain losses it may suffer as a result of inaccuracies or breach of representations and covenants committed by Tinuum Group. The Company also is a party to a contribution agreement with NexGen under which any party called upon to pay on a Tinuum Group Party Guaranty is entitled to receive contributions from the other party equal to 50% of the amount paid. The Company has not recorded a liability or expense provision related to this contingent obligation as it believes that it is not probable that a loss will occur with respect to the Tinuum Group Party Guaranties. As previously disclosed, effective December 31, 2021, the Section 45 tax credit period expired and, as a result, both Tinuum Group and Tinuum Services (discussed below) ceased their operations .

Supplemental Financial Informat

Supplemental Financial Information	9 Months Ended
	Sep. 30, 2023
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Supplemental Financial Information	Supplemental Financial Information Supplemental Balance Sheet Information The following table summarizes the components of Other long-term assets, net as presented in the Condensed Consolidated Balance Sheets: As of (in thousands) September 30, December 31, Other long-term assets, net: Right of use assets, operating leases, net $ 10,673 $ 7,734 Intangible assets, net 8,053 847 Spare parts, net 8,523 6,789 Upfront Customer Consideration 6,094 6,475 Mine development costs, net 7,063 5,478 Mine reclamation asset, net 1,566 1,641 Other 2,657 1,683 Total other long-term assets, net $ 44,629 $ 30,647 Spare parts include critical spares required to support plant operations. Parts and supply costs are determined using the lower of cost or estimated replacement cost. Parts are recorded as maintenance expenses in the period in which they are consumed or are capitalized if applicable. Mine development costs include acquisition costs, the cost of other development work and mitigation costs related to the Five Forks Mine and are depleted over the estimated life of the related mine reserves. The Company performs an evaluation of the recoverability of the carrying value of mine development costs to determine if facts and circumstances indicate that their carrying value may be impaired and if any adjustment is warranted. There were no indicators of impairment as of September 30, 2023. Mine reclamation asset, net represents an asset retirement obligation ("ARO") asset related to the Five Forks Mine and is depreciated over its estimated life. As of September 30, 2023 and December 31, 2022, Other includes the Highview Investment in the amount of $0.6 million and $0.6 million, respectively, that is carried at cost, less impairment, plus or minus observable changes in price for identical or similar investments of the same issuer. Fair value measurements, if any, represent Level 2 measurements. The Highview Investment is evaluated for indicators of impairment such as an event or change in circumstances that may have a significant adverse effect on the fair value of the investment. There were no changes to the carrying value of the Highview Investment for the three and nine months ended September 30, 2023 as there were no indicators of impairment or observable price changes for identical or similar investments. The following table details the components of Other current liabilities and Other long-term liabilities as presented in the Condensed Consolidated Balance Sheets: As of (in thousands) September 30, December 31, Other current liabilities: Current portion of operating lease obligations $ 2,045 $ 2,724 Income and other taxes payable 1,126 1,039 Current portion of mine reclamation liability 176 548 Other (1) 2,714 2,334 Total other current liabilities $ 6,061 $ 6,645 Other long-term liabilities: Operating lease obligations, long-term $ 8,797 $ 5,133 Mine reclamation liabilities 5,444 7,985 Other 866 733 Total other long-term liabilities $ 15,107 $ 13,851 (1) Included in Other current liabilities is $1.7 million related to the Repayment Agreement as defined in Note 10. As of September 30, 2023 and December 31, 2022, the Mine reclamation liability related to the Five Forks Mine is included in Other long-term liabilities. As of December 31, 2022, the Mine reclamation liability related to Marshall Mine was included in Other current liabilities and Other long-term liabilities. As part of the Arq Acquisition, the Company assumed asset retirement obligations related to two sites; a coal waste site adjacent to the Corbin Facility (the "Corbin ARO") and Mine 4 located in West Virginia (the "Mine 4 ARO"). The Company recorded these AROs at their estimated fair values and periodically adjusts them to reflect changes in the estimated present value resulting from the passage of time and revisions to the estimates of either the timing or amount of the reclamation costs. As of September 30, 2023, the Corbin ARO is included in Other long-term liabilities. As of September 30, 2023, the current portion of the Mine 4 ARO is included in Other current liabilities with the long-term portion included in Other long-term liabilities. The Mine reclamation liabilities represent AROs and changes for the nine months ended September 30, 2023 and year ended December 31, 2022 were as follows: As of (in thousands) September 30, 2023 December 31, 2022 Asset retirement obligations, beginning of period $ 8,533 $ 9,959 Asset retirement obligations assumed (1) 1,500 — Accretion 441 611 Liabilities settled (2) (4,854) (2,071) Changes due to scope and timing of reclamation — 34 Asset retirement obligations, end of period 5,620 8,533 Less current portion 176 548 Asset retirement obligations, long-term $ 5,444 $ 7,985 (1) Represents the Corbin ARO and Mine 4 ARO in the amounts of $0.5 million and $1.0 million, respectively. (2) Represents the removal of the Marshall Mine ARO as a result of the sale of Marshall Mine, LLC, as further discussed in Note 3.

Equity Method Investments

Equity Method Investments	9 Months Ended
	Sep. 30, 2023
Equity Method Investments and Joint Ventures [Abstract]
Equity Method Investments	Equity Method Investments Tinuum Group, LLC As of September 30, 2023 and December 31, 2022, the Company's ownership interest in Tinuum Group was 42.5%. For the three and nine months ended September 30, 2023 the Company recognized earnings from Tinuum Group of $0.2 million and $1.1 million, respectively, which was comprised solely of cash distributions received during these periods. For the three and nine months ended September 30, 2022, the Company recognized earnings from Tinuum Group of zero and $3.1 million, respectively, which was comprised solely of cash distributions received during these periods. In December 2022, the Company, certain of the other owners of Tinuum Group (collectively, the "Tinuum Group Owners") and Tinuum Group executed the Distribution and Repayment Agreement (the "Repayment Agreement"). Under the terms of the Repayment Agreement, the Tinuum Group Owners receive cash distributions (the "Distributions") equal to their percentage ownership and also are contractually liable for certain contingent liabilities of Tinuum Group (the "Tinuum Group Obligation") in amounts equal to their percentage ownership. In December 2022, the Company received its percentage share of the Distributions in the amount of $2.0 million and became contractually liable for $1.7 million of the Tinuum Group Obligation. As of September 30, 2023 and December 31, 2022, the Company's portion of the Tinuum Group Obligation is $1.7 million and $1.7 million, respectively, and is included in the "Other current liabilities" line item in the Condensed Consolidated Balance Sheets. In the event that the Tinuum Group Obligation is discharged in its entirety or settled for an amount that is less than the total Tinuum Group Obligation, the Company will recognize future equity earnings for the difference in its portion of the Tinuum Group Obligation and its pro rata share of the actual payment made by Tinuum Group, if any, for the Tinuum Group Obligation. In December 2022, the Company and Tinuum Group entered into an agreement (the "Tinuum Group Royalty Agreement") whereby the Company pays Tinuum Group a royalty (the "Tinuum Group Royalty") on certain of the Company's sales of its M-Prove TM products after the expiration of the Section 45 Tax Credit Program (beginning January 1, 2022) to certain of the former refined coal facilities owned by Tinuum Group and operated by Tinuum Services (the "M-45 Facilities"). The Tinuum Group Royalty is calculated based on "Net Profit" (as defined in the Tinuum Royalty Agreement) on the Company's sales of M-Prove TM product to certain of the M-45 Facilities. The Tinuum Group Royalty Agreement is for an initial term of five years with automatic renewals of five years unless the Company and Tinuum Group agree to terminate it. For the three and nine months ended September 30, 2023, the Company recognized $0.2 million and $0.6 million, respectively, of Tinuum Group Royalties, which are included in the "Consumables cost of revenues, excluding depreciation and amortization" line item in the Consolidated Statement of Operations. Tinuum Services, LLC As of September 30, 2023 and December 31, 2022, the Company had a 50% voting and economic interest in Tinuum Services. For the three and nine months ended September 30, 2023, the Company recognized income from Tinuum Services of $0.2 million and $0.5 million, respectively. For the three and nine months ended September 30, 2022, the Company recognized income from Tinuum Services of zero and $0.1 million, respectively. Cash Distributions The following table details the components of the cash distributions from the Company's respective equity method investments included as a component of cash flows from operating activities and investing activities in the Condensed Consolidated Statements of Cash Flows. Distributions from equity method investees are reported in the Condensed Consolidated Statements of Cash Flows as "Distributions from equity method investees, return on investment" as a component of cash flows from operations until such time as the carrying value in an equity method investee company is reduced to zero. Thereafter, such distributions are reported as "Distributions from equity method investees in excess of cumulative earnings" as a component of cash flows from investing activities. Nine Months Ended September 30, (in thousands) 2023 2022 Distributions from equity method investees, return on investment Tinuum Services $ — $ 2,297 Tinuum Group — — $ — $ 2,297 Distributions from equity method investees in excess of investment basis Tinuum Group $ 1,062 $ 3,137 Tinuum Services 450 179 $ 1,512 $ 3,316

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2023
Equity [Abstract]
Stockholders' Equity	Stockholders' Equity Equity Transactions On February 1, 2023, and pursuant to the Arq Acquisition, the Company entered into Subscription Agreements with certain persons (the "Subscribers"), which included existing shareholders of Arq Ltd., three of which were appointed to the Company's Board of Directors (the "Board"), pursuant to which the Subscribers subscribed for and purchased 3,842,315 shares of Common Stock for an aggregate purchase price of $15.4 million and at a price per share of $4.00 (such transaction, the "PIPE Investment"). On February 1, 2023, and as consideration for the Arq Acquisition, the Company issued 3,814,864 shares of its Common Stock and 5,294,462 shares of Series A Preferred Stock. On March 31, 2023, and pursuant to the Certificate of Designations, the Company declared a dividend of 68,464 shares of Series A Preferred Stock with respect to accrued dividends on the Series A Preferred Stock for the first quarter of 2023 (the "PIK Dividend"). The PIK Dividend was recorded at the estimated fair value of $0.2 million as of March 31, 2023 and was paid on April 21, 2023. On June 13, 2023, pursuant to stockholder approval, all shares of Series A Preferred Stock were converted into 5,362,926 shares of Common Stock. On July 14, 2023, the Board appointed Mr. Robert Rasmus to the positions of President and Chief Executive Officer effective July 17, 2023 succeeding Mr. Greg Marken. Also on this date, the Board increased the size of the Board from seven to eight directors and appointed Mr. Rasmus to fill the vacancy as a member of the Board effective immediately. On July 17, 2023, the Company entered into a Subscription Agreement (the "Subscription Agreement") with Mr. Rasmus and entities controlled by Mr. Rasmus, in connection with his appointment as the Company’s President and Chief Executive Officer. Pursuant to the Subscription Agreement, Mr. Rasmus subscribed for and agreed to purchase 950,000 shares of Common Stock from the Company for an aggregate purchase price of $1.8 million (at a price per share of approximately $1.90). In September 2023, the Company received cash of $1.0 million and issued 527,779 shares of Common Stock to Mr. Rasmus pursuant to the Subscription Agreement. The Company expects to receive the remaining cash of $0.8 million due under the Subscription Agreement during the fourth quarter of 2023 and, when received, will issue Mr. Rasmus 422,221 shares of Common Stock. Term Loan As consideration for the Term Loan, the Company issued 325,857 Warrant Shares, which were deemed to be equity securities. The Warrant Shares were recorded at their estimated fair value of $0.8 million to Additional paid in capital with a corresponding amount recorded as a debt discount on the Term Loan. Stock Repurchase Program As of September 30, 2023, the Company had $7.0 million remaining under a stock repurchase program, which will remain in effect until all amounts are utilized or is otherwise modified by the Board. Tax Asset Protection Plan U.S. federal income tax rules, and Section 382 of the Internal Revenue Code in particular, could substantially limit the use of net operating losses and tax credits if the Company experiences an "ownership change" (as defined in the Internal Revenue Code). In general, an ownership change occurs if there is a cumulative change in the ownership of the Company by "5 percent stockholders" that exceeds 50 percentage points over a rolling three-year period. An entity that experiences an ownership change generally will be subject to an annual limitation on its pre-ownership change tax loss and credit carryforwards equal to the equity value of the entity immediately before the ownership change, multiplied by the long-term, tax-exempt rate posted monthly by the Internal Revenue Service (subject to certain adjustments). The annual limitation would be increased each year to the extent that there is an unused limitation in a prior year. On May 5, 2017, the Board approved the declaration of a dividend of rights to purchase Series B Junior Participating Preferred Stock for each outstanding share of common stock as part of a tax asset protection plan (the "TAPP"), which is designed to protect the Company’s ability to utilize its net operating losses and tax credits. The TAPP is intended to act as a deterrent to any person acquiring beneficial ownership of 4.99% or more of the Company’s outstanding common stock. On April 11, 2023, the Board approved the Sixth Amendment to the TAPP (the "Sixth Amendment"), which amends the TAPP, as previously amended by the First, Second, Third, Fourth and Fifth Amendments that were approved the Board on April 6, 2018, April 5, 2019, April 9, 2020, April 9, 2021 and March 15, 2022, respectively. The Sixth Amendment amends the definition of "Final Expiration Date" under the TAPP to extend the duration of the TAPP and makes associated changes in connection therewith. Pursuant to the Sixth Amendment, the Final Expiration Date shall be the close of business on the earlier of (i) December 31, 2024 or (ii) December 31, 2023 if stockholder approval of the Sixth Amendment has not been obtained prior to such date. At the Company's 2023 Annual Meeting of Stockholders, the Company's stockholders approved the Sixth Amendment, thus the Final Expiration Date will be the close of business on December 31, 2024.

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2023
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-Based Compensation The Company grants equity-based awards to employees, non-employee directors and consultants that may include, but are not limited to, RSAs, PSUs, restricted stock units and stock options. Stock-based compensation expense related to manufacturing employees and administrative employees is included within the "Cost of revenue" and "Payroll and benefits" line items, respectively, in the Condensed Consolidated Statements of Operations. Stock-based compensation expense related to non-employee directors and consultants is included within the "General and administrative" line item in the Condensed Consolidated Statements of Operations. Total stock-based compensation expense for the three and nine months ended September 30, 2023 and 2022 was as follows: Three Months Ended September 30, Nine Months Ended September 30, (in thousands) 2023 2022 2023 2022 RSA expense $ 501 $ 420 $ 1,405 $ 1,240 PSU expense 151 87 355 215 Stock option expense 50 — 50 — Total stock-based compensation expense $ 702 $ 507 $ 1,810 $ 1,455 The amount of unrecognized compensation cost as of September 30, 2023, and the expected weighted-average period over which the cost will be recognized is as follows: As of September 30, 2023 (in thousands, expect years) Unrecognized Compensation Cost Expected Weighted- RSA expense $ 1,723 1.86 PSU expense 502 2.01 Stock option expense 679 2.79 Total unrecognized stock-based compensation expense $ 2,904 2.10 Restricted Stock Awards RSAs are typically granted with vesting terms of three years. The fair value of RSAs is determined based on the closing price of the Company's common stock on the authorization date of the grant multiplied by the number of shares subject to the stock award. Compensation expense for RSAs is generally recognized on a straight-line basis over the entire vesting period. A summary of RSA activity under the Company's various stock compensation plans for the nine months ended September 30, 2023 is presented below: Restricted Stock Weighted-Average Grant Date Fair Value Non-vested at January 1, 2023 652,962 $ 5.58 Granted 773,327 $ 1.91 Vested (391,893) $ 4.89 Forfeited (201,271) $ 3.29 Non-vested at September 30, 2023 833,125 $ 3.04 Performance Share Units Compensation expense for PSUs is recognized on a straight-line basis over the applicable service period, which is generally three years, based on the estimated fair value at the date of grant using a Monte Carlo simulation model. A summary of PSU activity for the nine months ended September 30, 2023 is presented below: Units Weighted-Average Aggregate Intrinsic Value (in thousands) Weighted-Average PSUs outstanding, January 1, 2023 148,591 $ 7.85 Granted 682,709 1.22 Vested / Settled (1) — — Forfeited / Canceled (162,382) 4.10 PSUs outstanding, September 30, 2023 668,918 $ 1.99 $ 1,191 2.01 (1) The number of units shown in the table above are based on target performance. The final number of shares of common stock issued may vary depending on the achievement of market conditions established within the awards, which could result in the actual number of shares issued ranging from zero to a maximum of two times the number of units shown in the above table. For the three and nine months ended September 30, 2023, no shares of common stock were issued upon vesting of PSUs. Stock Options Stock options vest over three years and have a contractual limit of ten years from the date of grant to exercise. The fair value of stock options granted is determined on the date of grant using the Black-Scholes option pricing model, and the related expense is recognized on a straight-line basis over the entire vesting period. The determination of the grant date fair value of stock options issued is affected by a number of variables, including the fair value of the Company’s common stock, the expected common stock price volatility over the expected term of the stock option, the expected term of the stock option, risk-free interest rates, and the expected dividend yield of the Company’s common stock. Risk-free interest rate - The risk-free interest rate for stock options granted during the period was determined by using a zero-coupon U.S. Treasury rate for the periods that coincided with the expected term of the options. Dividend yield - An expected dividend yield of zero was included in the calculations, as the Company does not currently pay nor does it anticipate paying dividends on its common stock as of the grant date of the stock options. Expected volatility - To calculate expected volatility, the historical volatility of the Company's common stock was used. Expected term - The Company’s expected term of stock options was calculated using a simplified method whereby the midpoint between the vesting date and the end of the contractual term is utilized to compute the expected term, as the Company does not have sufficient historical data for options with similar vesting and contractual terms. The following table indicates the weighted average assumptions that were used related to the awards granted in the three months ended September 30, 2023: Three Months Ended September 30, 2023 Stock options granted: 1,000,000 Risk-free interest rate 4 % Dividend yield — % Volatility 62 % Expected term (in years) 6 A summary of stock option activity for the nine months ended September 30, 2023 is presented below: Number of Options Weighted-Average Aggregate Intrinsic Value Weighted-Average Options outstanding, January 1, 2023 — $ — Options granted 1,000,000 3.00 Options exercised — — Options expired / forfeited — — Options outstanding, September 30, 2023 1,000,000 $ 3.00 $ — 9.79 Options vested and exercisable, September 30, 2023 — $ — $ — 0.00

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2023
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes For the three and nine months ended September 30, 2023 and 2022, the Company's income tax expense and effective tax rates were: Three Months Ended September 30, Nine Months Ended September 30, (in thousands, except for rate) 2023 2022 2023 2022 Income tax benefit $ — $ — $ (33) $ — Effective tax rate — % — % — % — % The Company incurred pretax loss for the nine months ended September 30, 2023 and expects to incur pretax loss for the year ending December 31, 2023. As a result, the effective rate for the three and nine months ended September 30, 2023 was zero as the resultant tax benefit was offset by a valuation allowance recorded as of September 30, 2023. The Company assesses a valuation allowance recorded against deferred tax assets at each reporting date. The determination of whether a valuation allowance for deferred tax assets is appropriate requires the evaluation of positive and negative evidence that can be objectively verified. Consideration must be given to all sources of taxable income available to realize deferred tax assets, including, as applicable, the future reversal of existing temporary differences, future taxable income forecasts exclusive of the reversal of temporary differences and carryforwards, taxable income in carryback years and tax planning strategies. In estimating income taxes, the Company assesses the relative merits and risks of the appropriate income tax treatment of transactions taking into account statutory, judicial and regulatory guidance.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2023
Subsequent Events [Abstract]
Subsequent Events	Subsequent EventsUnless disclosed elsewhere in the notes to the Condensed Consolidated Financial Statements, there were no significant matters that occurred subsequent to September 30, 2023.

Organization and Basis of Pre_2

Organization and Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Basis of Presentation	The accompanying Condensed Consolidated Financial Statements of ADES are unaudited and have been prepared in conformity with accounting principles generally accepted in the United States ("U.S. GAAP") and with Article 10 of Regulation S-X of the Securities and Exchange Commission. In compliance with those instructions, certain information and footnote disclosures normally included in annual consolidated financial statements prepared in accordance with U.S. GAAP have been condensed or omitted. The unaudited Condensed Consolidated Financial Statements of ADES in this quarterly report ("Quarterly Report") are presented on a consolidated basis and include ADES and its wholly-owned subsidiaries (collectively, the "Company"). Also included within the unaudited Condensed Consolidated Financial Statements are the Company's unconsolidated equity investments, Tinuum Group and Tinuum Services, which are accounted for under the equity method of accounting, and Highview Enterprises Limited (the "Highview Investment"), which is accounted for in accordance with U.S. GAAP applicable to equity investments that do not qualify for the equity method of accounting. Results of operations and cash flows for the interim periods are not necessarily indicative of the results that may be expected for the entire year. All significant intercompany transactions and accounts were eliminated in consolidation for all periods presented in this Quarterly Report. In the opinion of management, these Condensed Consolidated Financial Statements include all normal and recurring adjustments considered necessary for a fair presentation of the results of operations, financial position, stockholders' equity and cash flows for the interim periods presented. These Condensed Consolidated Financial Statements should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2022 (the "2022 Form 10-K"). Significant accounting policies disclosed therein have not changed.
Earnings (Loss) Per Share	Basic earnings (loss) per share is computed using the weighted-average number of shares of common stock outstanding during the reporting period. Diluted earnings (loss) per share is computed in a manner consistent with that of basic earnings per share, while considering other potentially dilutive securities. For the three and nine months ended September 30, 2023 and 2022, potentially dilutive securities consist of unvested restricted stock awards ("RSAs"), stock options and contingent performance stock units ("PSUs").
Use of Estimates	The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. There have been no changes in the Company's critical accounting estimates from those that were disclosed in the 2022 Form 10-K. Actual results could differ from these estimates.
Risks and Uncertainties	The Company is principally dependent on the operations of its APT business and its cash on hand to provide liquidity over the near and long term. The Company's revenues, sales volumes, earnings and cash flows are significantly affected by prices of competing power generation sources such as natural gas and renewable energy. During periods of low natural gas prices, natural gas provides a competitive alternative to coal-fired power generation and therefore, coal consumption for purposes of power generation may be reduced, which in turn reduces the demand for the Company's products. However, during periods of higher prices for competing power generation sources, there is an increase in coal consumption and thus demand for the Company's products also increases. In addition, coal consumption for purposes of power generation and demand for the Company's products are affected by the demand for electricity, which is higher in the warmer and colder months of the year. As a result, the Company's interim period results are subject to seasonal variations whereby its revenues and cost of revenues tend to be higher in its first and third fiscal quarters compared to its second and fourth fiscal quarters. Abnormal temperatures during the summer and winter months may significantly affect coal consumption and impurities within various municipalities' water sources, and thus impact the demand for the Company's products.
Concentration of credit risk	The Company is exposed to concentrations of credit risk primarily related to its customer accounts receivable. The Company regularly monitors its credit risk to mitigate the possibility of current and future exposures resulting in a loss. Historically, the losses related to credit risk have been immaterial. The Company evaluates the creditworthiness of its customers prior to entering into agreements to sell its products and, as necessary, throughout the life of the customer relationship.
Reclassifications	Certain balances have been reclassified from the prior year to conform to the current year presentation. Such reclassifications had no effect on the Company’s results of operations or financial position in any of the periods presented.

Organization and Basis of Pre_3

Organization and Basis of Presentation (Tables)	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Schedule of Calculations of Basic and Diluted Loss Per Share	The following table sets forth the calculations of basic and diluted loss per share: Three Months Ended September 30, Nine Months Ended September 30, (in thousands, except per share amounts) 2023 2022 2023 2022 Net loss $ (2,175) $ (2,391) $ (15,539) $ (5,750) Less: Dividends declared on redeemable preferred stock — — 157 — Loss attributable to common stockholders $ (2,175) $ (2,391) $ (15,696) $ (5,750) Basic weighted-average common shares outstanding 31,807 18,487 27,894 18,435 Add: dilutive effect of equity instruments — — — — Diluted weighted-average shares outstanding 31,807 18,487 27,894 18,435 Loss per share - basic $ (0.07) $ (0.13) $ (0.56) $ (0.31) Loss per share - diluted $ (0.07) $ (0.13) $ (0.56) $ (0.31)

Arq Acquisition (Tables)

Arq Acquisition (Tables)	9 Months Ended
	Sep. 30, 2023
Business Combination and Asset Acquisition [Abstract]
Schedule of Final Purchase Price Allocation to the Assets Acquired and Liabilities Assumed	The following table provides the final purchase price allocation to the assets acquired and liabilities assumed as of the Acquisition Date: (in thousands) Purchase Price Allocation Fair value of assets acquired: Cash $ 1,411 Prepaid expenses and other current assets 2,229 Restricted cash, long-term 814 Property, plant and equipment, net 39,159 Other long-term assets, net 11,717 Amount attributable to assets acquired 55,330 Fair Value of liabilities assumed: Accounts payable and accrued expenses 9,806 Current portion of long-term debt 494 Other current liabilities 103 Long-term debt, net of current portion 9,199 Other long-term liabilities 4,523 Amount attributable to liabilities assumed 24,125 Net assets acquired $ 31,205 The following represents the intangible asset identified as part of the Arq Acquisition and which is included in "Other long-term-assets, net" in the table above: (in thousands) Amount Weighted Average Useful Life (years) Developed technology $ 7,700 20
Schedule of Revenues and Net Loss for Arq	The amounts of year to date revenues and net loss for Arq for the period from the Acquisition Date to September 30, 2023 are as follows: Nine Months Ended September 30, (in thousands) 2023 Revenues $ — Net loss $ (9,199)
Schedule of Pro Forma Revenues	Since Arq had no revenues for the nine months ended September 30, 2023 or 2022, pro forma revenues are the same as the Company's reported revenues for those periods. Nine Months Ended September 30, (in thousands) 2023 2022 Revenues $ 71,079 $ 79,578 Net loss $ (12,100) $ (53,752)

Revenues (Tables)

Revenues (Tables)	9 Months Ended
	Sep. 30, 2023
Revenue from Contract with Customer [Abstract]
Schedule of Accounts Receivables	The following table shows the components of the Company's Receivables, net: As of (in thousands) September 30, 2023 December 31, 2022 Trade receivables, net $ 14,138 $ 13,789 Other receivables 87 75 Receivables, net $ 14,225 $ 13,864

Inventories, net (Tables)

Inventories, net (Tables)	9 Months Ended
	Sep. 30, 2023
Inventory Disclosure [Abstract]
Schedule of Inventory	The following table summarizes the Company's inventories recorded at the lower of average cost or net realizable value, as of September 30, 2023 and December 31, 2022: As of (in thousands) September 30, 2023 December 31, 2022 Product inventory, net $ 8,659 $ 9,479 Raw material inventory 9,890 8,349 Total inventories, net $ 18,549 $ 17,828

Debt Obligations (Tables)

Debt Obligations (Tables)	9 Months Ended
	Sep. 30, 2023
Debt Disclosure [Abstract]
Schedule of Debt	As of (in thousands) September 30, 2023 December 31, 2022 Term Loan due February 2027, related party $ 10,000 $ — Arq Loan due January 2036 9,659 — Finance lease obligations 3,727 4,581 23,386 4,581 Unamortized debt discounts (880) — Unamortized debt issuance costs (1,336) — 21,170 4,581 Less: Current maturities (1,991) (1,131) Total long-term debt obligations $ 19,179 $ 3,450

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2023
Leases [Abstract]
Schedule of Operating and Finance Lease Right-Of-Use ("ROU") Assets and Liabilities	The Company's operating and finance lease right-of-use ("ROU") assets and liabilities as of September 30, 2023 and December 31, 2022 consisted of the following items (in thousands): As of Leases September 30, 2023 December 31, 2022 Operating Leases Operating lease right-of-use assets, net of accumulated amortization (1) $ 10,673 $ 7,734 Operating lease obligations, current $ 2,045 $ 2,724 Long-term operating lease obligations 8,797 5,133 Total operating lease obligation $ 10,842 $ 7,857 Finance Leases Finance lease right-of-use assets, net of accumulated amortization (2) $ 1,904 $ 2,565 Finance lease obligations, current $ 1,477 $ 1,131 Long-term finance lease obligations 2,250 3,450 Total finance lease obligations $ 3,727 $ 4,581 (1) Operating lease ROU assets are reported net of accumulated amortization of $5.1 million and $4.4 million as of September 30, 2023 and December 31, 2022, respectively. (2) Finance lease ROU assets are reported net of accumulated amortization of $2.5 million and $2.0 million as of September 30, 2023 and December 31, 2022, respectively. Lease financial information as of and for the three and nine months ended September 30, 2023 and 2022 is provided in the following table: Three Months Ended September 30, Nine Months Ended September 30, (in thousands) 2023 2022 2023 2022 Finance lease cost: Amortization of right-of-use assets $ 215 $ 236 $ 661 $ 607 Interest on lease liabilities 59 76 190 240 Operating lease cost 1,000 805 3,017 2,389 Short-term lease cost 481 373 1,132 832 Variable lease cost (1) 81 5 145 12 Total lease cost $ 1,836 $ 1,495 $ 5,145 $ 4,080 Other Information: Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for finance leases $ 190 $ 240 Operating cash flows for operating leases $ 2,087 $ 2,118 Financing cash flows for finance leases $ 855 $ 913 Right-of-use assets obtained in exchange for new finance lease liabilities $ — $ 1,641 Right-of-use assets obtained in exchange for new operating lease liabilities $ 1,947 $ 3,563 Weighted-average remaining lease term - finance leases 2.1 years 2.9 years Weighted-average remaining lease term - operating leases 7.8 years 4.2 years Weighted-average discount rate - finance leases 5.9 % 5.9 % Weighted-average discount rate - operating leases 12.7 % 6.1 % (1) Primarily includes common area maintenance, property taxes and insurance payable to lessors.

Supplemental Financial Inform_2

Supplemental Financial Information (Tables)	9 Months Ended
	Sep. 30, 2023
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Schedule of Other Long Term Assets	The following table summarizes the components of Other long-term assets, net as presented in the Condensed Consolidated Balance Sheets: As of (in thousands) September 30, December 31, Other long-term assets, net: Right of use assets, operating leases, net $ 10,673 $ 7,734 Intangible assets, net 8,053 847 Spare parts, net 8,523 6,789 Upfront Customer Consideration 6,094 6,475 Mine development costs, net 7,063 5,478 Mine reclamation asset, net 1,566 1,641 Other 2,657 1,683 Total other long-term assets, net $ 44,629 $ 30,647
Schedule of Other Liabilities	The following table details the components of Other current liabilities and Other long-term liabilities as presented in the Condensed Consolidated Balance Sheets: As of (in thousands) September 30, December 31, Other current liabilities: Current portion of operating lease obligations $ 2,045 $ 2,724 Income and other taxes payable 1,126 1,039 Current portion of mine reclamation liability 176 548 Other (1) 2,714 2,334 Total other current liabilities $ 6,061 $ 6,645 Other long-term liabilities: Operating lease obligations, long-term $ 8,797 $ 5,133 Mine reclamation liabilities 5,444 7,985 Other 866 733 Total other long-term liabilities $ 15,107 $ 13,851 (1) Included in Other current liabilities is $1.7 million related to the Repayment Agreement as defined in Note 10.
Schedule of Change in Asset Retirement Obligation	The Mine reclamation liabilities represent AROs and changes for the nine months ended September 30, 2023 and year ended December 31, 2022 were as follows: As of (in thousands) September 30, 2023 December 31, 2022 Asset retirement obligations, beginning of period $ 8,533 $ 9,959 Asset retirement obligations assumed (1) 1,500 — Accretion 441 611 Liabilities settled (2) (4,854) (2,071) Changes due to scope and timing of reclamation — 34 Asset retirement obligations, end of period 5,620 8,533 Less current portion 176 548 Asset retirement obligations, long-term $ 5,444 $ 7,985 (1) Represents the Corbin ARO and Mine 4 ARO in the amounts of $0.5 million and $1.0 million, respectively. (2) Represents the removal of the Marshall Mine ARO as a result of the sale of Marshall Mine, LLC, as further discussed in Note 3.

Equity Method Investments (Tabl

Equity Method Investments (Tables)	9 Months Ended
	Sep. 30, 2023
Equity Method Investments and Joint Ventures [Abstract]
Schedule of Equity Method Investments	The following table details the components of the cash distributions from the Company's respective equity method investments included as a component of cash flows from operating activities and investing activities in the Condensed Consolidated Statements of Cash Flows. Distributions from equity method investees are reported in the Condensed Consolidated Statements of Cash Flows as "Distributions from equity method investees, return on investment" as a component of cash flows from operations until such time as the carrying value in an equity method investee company is reduced to zero. Thereafter, such distributions are reported as "Distributions from equity method investees in excess of cumulative earnings" as a component of cash flows from investing activities. Nine Months Ended September 30, (in thousands) 2023 2022 Distributions from equity method investees, return on investment Tinuum Services $ — $ 2,297 Tinuum Group — — $ — $ 2,297 Distributions from equity method investees in excess of investment basis Tinuum Group $ 1,062 $ 3,137 Tinuum Services 450 179 $ 1,512 $ 3,316

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2023
Share-Based Payment Arrangement [Abstract]
Schedule of Allocation of Compensation Expense	Total stock-based compensation expense for the three and nine months ended September 30, 2023 and 2022 was as follows: Three Months Ended September 30, Nine Months Ended September 30, (in thousands) 2023 2022 2023 2022 RSA expense $ 501 $ 420 $ 1,405 $ 1,240 PSU expense 151 87 355 215 Stock option expense 50 — 50 — Total stock-based compensation expense $ 702 $ 507 $ 1,810 $ 1,455
Schedule of Unrecognized Compensation Cost	The amount of unrecognized compensation cost as of September 30, 2023, and the expected weighted-average period over which the cost will be recognized is as follows: As of September 30, 2023 (in thousands, expect years) Unrecognized Compensation Cost Expected Weighted- RSA expense $ 1,723 1.86 PSU expense 502 2.01 Stock option expense 679 2.79 Total unrecognized stock-based compensation expense $ 2,904 2.10
Schedule of Restricted Stock Activity	A summary of RSA activity under the Company's various stock compensation plans for the nine months ended September 30, 2023 is presented below: Restricted Stock Weighted-Average Grant Date Fair Value Non-vested at January 1, 2023 652,962 $ 5.58 Granted 773,327 $ 1.91 Vested (391,893) $ 4.89 Forfeited (201,271) $ 3.29 Non-vested at September 30, 2023 833,125 $ 3.04
Schedule of Performance Shares Units	A summary of PSU activity for the nine months ended September 30, 2023 is presented below: Units Weighted-Average Aggregate Intrinsic Value (in thousands) Weighted-Average PSUs outstanding, January 1, 2023 148,591 $ 7.85 Granted 682,709 1.22 Vested / Settled (1) — — Forfeited / Canceled (162,382) 4.10 PSUs outstanding, September 30, 2023 668,918 $ 1.99 $ 1,191 2.01 (1) The number of units shown in the table above are based on target performance. The final number of shares of common stock issued may vary depending on the achievement of market conditions established within the awards, which could result in the actual number of shares issued ranging from zero to a maximum of two times the number of units shown in the above table. For the three and nine months ended September 30, 2023, no shares of common stock were issued upon vesting of PSUs.
Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions	The following table indicates the weighted average assumptions that were used related to the awards granted in the three months ended September 30, 2023: Three Months Ended September 30, 2023 Stock options granted: 1,000,000 Risk-free interest rate 4 % Dividend yield — % Volatility 62 % Expected term (in years) 6
Summary of Option Activity	A summary of stock option activity for the nine months ended September 30, 2023 is presented below: Number of Options Weighted-Average Aggregate Intrinsic Value Weighted-Average Options outstanding, January 1, 2023 — $ — Options granted 1,000,000 3.00 Options exercised — — Options expired / forfeited — — Options outstanding, September 30, 2023 1,000,000 $ 3.00 $ — 9.79 Options vested and exercisable, September 30, 2023 — $ — $ — 0.00

Income Taxes (Tables)

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2023
Income Tax Disclosure [Abstract]
Schedule of Income Tax Expense and Effective Tax Rates	For the three and nine months ended September 30, 2023 and 2022, the Company's income tax expense and effective tax rates were: Three Months Ended September 30, Nine Months Ended September 30, (in thousands, except for rate) 2023 2022 2023 2022 Income tax benefit $ — $ — $ (33) $ — Effective tax rate — % — % — % — %

Organization and Basis of Pre_4

Organization and Basis of Presentation - Schedule of Calculations of Basic and Diluted Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022
Accounting Policies [Abstract]
Net loss	$ (2,175)	$ (5,856)	$ (7,508)	$ (2,391)	$ (326)	$ (3,033)	$ (15,539)	$ (5,750)
Less: Dividends declared on redeemable preferred stock	0			0			157	0
Loss attributable to common stockholders, basic	(2,175)			(2,391)			(15,696)	(5,750)
Loss attributable to common stockholders, diluted	$ (2,175)			$ (2,391)			$ (15,696)	$ (5,750)
Basic weighted-average common shares outstanding (in shares)	31,807			18,487			27,894	18,435
Add: dilutive effect of equity instruments (in shares)	0			0			0	0
Diluted weighted-average shares outstanding (in shares)	31,807			18,487			27,894	18,435
Loss per share - basic (in dollars per share)	$ (0.07)			$ (0.13)			$ (0.56)	$ (0.31)
Loss per share - diluted (in dollars per share)	$ (0.07)			$ (0.13)			$ (0.56)	$ (0.31)
Total shares excluded from diluted shares outstanding (in shares)	2,300			800			1,400	700

Organization and Basis of Pre_5

Organization and Basis of Presentation - Concentration of Credit Risk (Narrative) (Details)	Sep. 30, 2023 USD ($) financialInstitution
Accounting Policies [Abstract]
Number of financial institutions | financialInstitution	2
Time deposits, $250,000 or more | $	$ 250,000

Arq Acquisition - Narrative (De

Arq Acquisition - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands				9 Months Ended		12 Months Ended
	Apr. 21, 2023	Mar. 31, 2023	Feb. 01, 2023	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Jun. 13, 2023	Dec. 31, 2022
Business Acquisition [Line Items]
Paid-in-kind dividend on Series A Preferred Stock	$ 200			$ 157	$ 0
Preferred stock, shares issued (in shares)				0		0		0
Preferred stock par value (in dollars per share)				$ 0.001		$ 0.001		$ 0.001
Series A Preferred Stock
Business Acquisition [Line Items]
Preferred stock dividends declared on redeemable preferred stock (in shares)		68,464
Arq Limited
Business Acquisition [Line Items]
Consideration transferred			$ 31,200
Acquisition related costs			$ 8,700
Preferred stock, shares issued (in shares)			833,914
Preferred stock par value (in dollars per share)			$ 3.46
Contingent consideration, liability			$ 3,300
Increase in payroll and benefits for compensation expense					1,900
Decrease in depreciation and amortization				$ 200	1,200
Increase in intangible assets				100	300
Increase in interest expense				$ 200	$ 1,400
Reversal of transaction costs						$ 3,800
Arq Limited | Series A Preferred Stock
Business Acquisition [Line Items]
Preferred stock, shares designated (in shares)			8,900,000
Shares issued (in dollars per share)			$ 4
Effective interest rate			8%
Arq Limited | Common Stock
Business Acquisition [Line Items]
Business acquisition, issued number of shares (in shares)			3,814,864
Business acquisition, issued number of shares issuable, value			$ 12,400
Arq Limited | Preferred Stock
Business Acquisition [Line Items]
Business acquisition, issued number of shares (in shares)			5,294,462
Business acquisition, issued number of shares issuable, value			$ 18,800
Arq Acquisition | Series A Preferred Stock
Business Acquisition [Line Items]
Issuance of stock upon conversion of preferred stock (in shares)							5,362,926

Arq Acquisition - Schedule of F

Arq Acquisition - Schedule of Final Purchase Price Allocation to the Assets Acquired and Liabilities Assumed (Details) - Arq Limited $ in Thousands	Feb. 01, 2023 USD ($)
Business Acquisition [Line Items]
Cash	$ 1,411
Prepaid expenses and other current assets	2,229
Restricted cash, long-term	814
Property, plant and equipment, net	39,159
Other long-term assets, net	11,717
Amount attributable to assets acquired	55,330
Accounts payable and accrued expenses	9,806
Current portion of long-term debt	494
Other current liabilities	103
Long-term debt, net of current portion	9,199
Other long-term liabilities	4,523
Amount attributable to liabilities assumed	24,125
Net assets acquired	31,205
Developed technology
Business Acquisition [Line Items]
Amount	$ 7,700
Weighted Average Useful Life (years)	20 years

Arq Acquisition - Schedule of R

Arq Acquisition - Schedule of Revenues and Net Loss for Arq (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022
Business Acquisition [Line Items]
Revenues	$ 29,829			$ 28,437			$ 71,079	$ 79,578
Net loss	$ (2,175)	$ (5,856)	$ (7,508)	$ (2,391)	$ (326)	$ (3,033)	(15,539)	$ (5,750)
Arq Acquisition
Business Acquisition [Line Items]
Revenues							0
Net loss							$ (9,199)

Arq Acquisition - Schedule of P

Arq Acquisition - Schedule of Pro Forma Revenues (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Business Combination and Asset Acquisition [Abstract]
Revenues	$ 71,079	$ 79,578
Net loss	$ (12,100)	$ (53,752)

Marshall Mine (Details)

Marshall Mine (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Mar. 27, 2023
Business Acquisition [Line Items]
Gain on change in estimate, asset retirement obligation	$ 0	$ 0	$ 2,695	$ 0
Marshall Mine
Business Acquisition [Line Items]
Consideration					$ 2,200
Liabilities					$ 4,900
Gain on change in estimate, asset retirement obligation			$ 2,700

Revenues - Narrative (Details)

Revenues - Narrative (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Revenue from Contract with Customer [Abstract]
Collection terms			Credit terms are generally net 30 - 45 days from the date of invoice.
Revenue from Contract with Customer Benchmark | Geographic Concentration Risk | Canada
Disaggregation of Revenue [Line Items]
Percent of revenue generated	7%	7%	8%	9%

Revenues - Schedule of Accounts

Revenues - Schedule of Accounts Receivables (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivables, net	$ 14,225	$ 13,864
Other receivables	87	75
Trade receivables, net
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivables, net	$ 14,138	$ 13,789

Inventories, net (Details)

Inventories, net (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Inventory Disclosure [Abstract]
Product inventory, net	$ 8,659	$ 9,479
Raw material inventory	9,890	8,349
Total inventories, net	$ 18,549	$ 17,828

Debt Obligations - Schedule of

Debt Obligations - Schedule of Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Arq Loan due January 2036	$ 9,659	$ 0
Finance lease obligations	3,727	4,581
Long-term debt	23,386	4,581
Unamortized debt discounts	(880)	0
Unamortized debt issuance costs	(1,336)	0
Long-term debt	21,170	4,581
Less: Current maturities	(1,991)	(1,131)
Total long-term debt obligations	19,179	3,450
Term Loan
Debt Instrument [Line Items]
Term Loan due February 2027, related party	$ 10,000	$ 0

Debt Obligations - Narrative (D

Debt Obligations - Narrative (Details) - USD ($)			9 Months Ended
	Feb. 01, 2023	Jan. 27, 2021	Sep. 30, 2023	Jun. 02, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Unamortized discount			$ 880,000		$ 0
Debt issuance costs			$ 9,659,000		$ 0
Debt instrument, post-transaction from exercise of warrant	1%
CF Global Credit, LP
Debt Instrument [Line Items]
Issuance of warrant (in shares)	325,457,000
Warrant shares, percent of fully diluted share capital	1%
Exercise price of warrants (in dollars per share)	$ 0.01
Term	7 years
Secured Debt
Debt Instrument [Line Items]
Proceeds from issuance of debt	$ 10,000,000
Unamortized discount	200,000
Net cash proceeds	8,500,000
Debt issuance costs	$ 1,300,000
Issuance of warrant (in shares)	325,857
Secured Debt
Debt Instrument [Line Items]
Exercise price of warrants (in dollars per share)	$ 0.01
Debt instrument, covenant loan to value ratio	0.40
Secured Debt | Arq Limited
Debt Instrument [Line Items]
Unamortized discount	$ 300,000
Face amount	10,000,000
Estimated fair value	$ 9,700,000
Periodic payment, principal		$ 100,000
Debt instrument, fee amount				$ 50,000
Debt instrument, collateral amount				$ 700,000
Indebtedness percentage			400%
Debt instrument, annual increase			20%
Equity percentage			1.25
Secured Debt | Arq Limited | Promissory Note A
Debt Instrument [Line Items]
Face amount		8,000,000
Secured Debt | Arq Limited | Promissory Note B
Debt Instrument [Line Items]
Face amount		$ 2,000,000
Secured Debt | Between 1 And 36 Moths
Debt Instrument [Line Items]
Debt instrument, prepayment premium	2%
Secured Debt | Between 37 Months And Maturity Date
Debt Instrument [Line Items]
Debt instrument, prepayment premium	1%
Secured Debt | Adjusted Term SOFR for an Interest Period of One Month in Effect on the Third U.S. Government Securities Business Day
Debt Instrument [Line Items]
Debt instrument, prepayment premium	2%
Secured Debt | Beginning March 31, 2023
Debt Instrument [Line Items]
Debt covenant, minimum cash balance requirement	$ 5,000,000
Secured Debt | Fiscal Year 2023
Debt Instrument [Line Items]
Debt covenant, minimum annual Revenue requirement	70,000,000
Secured Debt | Fiscal Year 2024
Debt Instrument [Line Items]
Debt covenant, minimum annual Revenue requirement	85,000,000
Debt covenant, minimum consolidated EBITDA requirement	3,000,000
Secured Debt | Fiscal Year 2025 and Thereafter
Debt Instrument [Line Items]
Debt covenant, minimum annual Revenue requirement	100,000,000
Debt covenant, minimum consolidated EBITDA requirement	$ 16,000,000
Secured Debt | Through January 2026 | Arq Limited
Debt Instrument [Line Items]
Interest rate, stated percentage		6%
Secured Debt | Penalty Year 2024 | Arq Limited
Debt Instrument [Line Items]
Prepayment penalty, percentage			3%
Secured Debt | Penalty Year 2025 | Arq Limited
Debt Instrument [Line Items]
Prepayment penalty, percentage			2%
Secured Debt | Penalty Year 2026 | Arq Limited
Debt Instrument [Line Items]
Prepayment penalty, percentage			1%
Secured Debt | SOFR
Debt Instrument [Line Items]
Debt instrument, floor rate percentage	1%
Debt instrument, cap rate percentage	2%
Debt instrument, percent of paid in cash	9%
Debt instrument, percent of paid in kind	5%
Secured Debt | SOFR | Adjusted Term SOFR for an Interest Period of One Month in Effect on the Third U.S. Government Securities Business Day
Debt Instrument [Line Items]
Debt instrument, interest rate	14%
Secured Debt | Base Rate
Debt Instrument [Line Items]
Debt instrument, percent of paid in cash	8%
Secured Debt | Prime Rate | After January 2026 | Arq Limited
Debt Instrument [Line Items]
Interest rate, stated percentage		2.75%

Leases - Schedule of Operating

Leases - Schedule of Operating and Finance Lease Right-Of-Use ("ROU") Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Operating Leases
Operating lease right-of-use assets, net of accumulated amortization	$ 10,673	$ 7,734
Operating lease obligations, current	2,045	2,724
Long-term operating lease obligations	8,797	5,133
Total operating lease obligation	10,842	7,857
Finance Leases
Finance lease right-of-use assets, net of accumulated amortization	1,904	2,565
Finance lease obligations, current	1,477	1,131
Long-term finance lease obligations	2,250	3,450
Total finance lease obligations	3,727	4,581
Operating lease, accumulated amortization	5,100	4,400
Finance lease, accumulated amortization	$ (2,500)	$ (2,000)

Leases - Narrative (Details)

Leases - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Lessee, Lease, Description [Line Items]
Operating lease, right-of-use asset, statement of financial position [Extensible Enumeration]	Other long-term assets, net		Other long-term assets, net		Other long-term assets, net
Operating lease, liability, current, statement of financial position [Extensible List]	Other current liabilities		Other current liabilities		Other current liabilities
Operating lease, liability, noncurrent, statement of financial position [Extensible List]	Other long-term liabilities		Other long-term liabilities		Other long-term liabilities
Operating lease, expense	$ 1.6	$ 1.2	$ 4.3	$ 3.2
General and Administrative Expense
Lessee, Lease, Description [Line Items]
Operating lease, expense	0.4	0.1	0.9	0.4
Consumables
Lessee, Lease, Description [Line Items]
Operating lease, expense	$ 1.2	$ 1.1	$ 3.4	$ 2.9

Leases - Schedule of Lease Liab

Leases - Schedule of Lease Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Finance lease cost:
Amortization of right-of-use assets	$ 215	$ 236	$ 661	$ 607
Interest on lease liabilities	59	76	190	240
Operating lease cost	1,000	805	3,017	2,389
Short-term lease cost	481	373	1,132	832
Variable lease cost	81	5	145	12
Total lease cost	$ 1,836	$ 1,495	5,145	4,080
Operating cash flows for finance leases			190	240
Operating cash flows for operating leases			2,087	2,118
Financing cash flows for finance leases			855	913
Right-of-use assets obtained in exchange for new finance lease liabilities			0	1,641
Right-of-use assets obtained in exchange for new operating lease liabilities			$ 1,947	$ 3,563
Weighted-average remaining lease term - finance leases	2 years 1 month 6 days	2 years 10 months 24 days	2 years 1 month 6 days	2 years 10 months 24 days
Weighted-average remaining lease term - operating leases	7 years 9 months 18 days	4 years 2 months 12 days	7 years 9 months 18 days	4 years 2 months 12 days
Weighted-average discount rate - finance leases	5.90%	5.90%	5.90%	5.90%
Weighted-average discount rate - operating leases	12.70%	6.10%	12.70%	6.10%

Commitments and Contingencies (

Commitments and Contingencies (Details)		1 Months Ended
	Jul. 17, 2023 USD ($) shares	Aug. 31, 2022 USD ($)	Sep. 30, 2023 USD ($) entity	Dec. 31, 2022 USD ($)
Stock options granted:
Accelerated cost	$ 800,000
Retention liability				$ 1,400,000
Retention agreements amount of retention pay		$ 1,000,000
Other Commitments [Line Items]
Restricted cash, long-term			$ 8,500,000	10,000,000
Supply agreement performance bond			3,700,000
Contract with customer, liability			400,000
Related Party Transaction [Line Items]
Liability or expense			$ 6,061,000	6,645,000
Tinuum Group, LLC
Related Party Transaction [Line Items]
Number of entities affiliated with related parties | entity			2
Limited guarantees (as percent)			50%
Liability or expense			$ 0
Five Forks Mine
Other Commitments [Line Items]
Surety bond amount			7,500,000	7,500,000
Corbin Facilities
Other Commitments [Line Items]
Surety bond amount			3,000,000
West Virginia ("Mine 4")
Other Commitments [Line Items]
Surety bond amount			700,000
Restricted cash, long-term			$ 400,000
Marshall Mine
Other Commitments [Line Items]
Surety bond amount				$ 16,600,000
Restricted Stock
Stock options granted:
Shares accelerated, number (in shares) | shares	49,715
PSU Granted 2021
Stock options granted:
Shares accelerated, number (in shares) | shares	25,941
PSU Granted 2022
Stock options granted:
Shares accelerated, number (in shares) | shares	15,988
PSU Granted 2023
Stock options granted:
Shares accelerated, number (in shares) | shares	19,834

Supplemental Financial Inform_3

Supplemental Financial Information - Schedule of Other Long Term Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Other long-term assets, net:
Right of use assets, operating leases, net	$ 10,673	$ 7,734
Intangible assets, net	8,053	847
Spare parts, net	8,523	6,789
Upfront Customer Consideration	6,094	6,475
Mine development costs, net	7,063	5,478
Mine reclamation asset, net	1,566	1,641
Other	2,657	1,683
Total other long-term assets, net	$ 44,629	$ 30,647

Supplemental Financial Inform_4

Supplemental Financial Information - Narrative (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Highview Enterprises Limited
Related Party Transaction [Line Items]
Equity method investments	$ 0.6	$ 0.6

Supplemental Financial Inform_5

Supplemental Financial Information - Schedule of Other Liabilities (Details) - USD ($) $ in Thousands	1 Months Ended
	Dec. 31, 2022	Sep. 30, 2023
Other current liabilities:
Operating lease, liability, current, statement of financial position [Extensible List]	Total other current liabilities	Total other current liabilities
Current portion of operating lease obligations	$ 2,724	$ 2,045
Income and other taxes payable	1,039	1,126
Current portion of mine reclamation liability	548	176
Other	2,334	2,714
Total other current liabilities	$ 6,645	$ 6,061
Other long-term liabilities:
Operating lease, liability, noncurrent, statement of financial position [Extensible List]	Total other long-term liabilities	Total other long-term liabilities
Operating lease obligations, long-term	$ 5,133	$ 8,797
Mine reclamation liabilities	7,985	5,444
Other	733	866
Total other long-term liabilities	13,851	$ 15,107
Tinuum Group, LLC
Other long-term liabilities:
Liabilities assumed	$ 1,700

Supplemental Financial Inform_6

Supplemental Financial Information - Schedule of Change in Asset Retirement Obligation (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Dec. 31, 2022
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset retirement obligations, beginning of period	$ 8,533	$ 9,959
Asset retirement obligations assumed	1,500	0
Accretion	441	611
Liabilities settled	(4,854)	(2,071)
Changes due to scope and timing of reclamation	0	34
Asset retirement obligations, end of period	5,620	8,533
Less current portion	176	548
Asset retirement obligations, long-term	5,444	7,985
Business Acquisition [Line Items]
Asset retirement obligations assumed	1,500	$ 0
Corbin ARO
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset retirement obligations assumed	500
Business Acquisition [Line Items]
Asset retirement obligations assumed	500
Mine 4 ARO
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset retirement obligations assumed	1,000
Business Acquisition [Line Items]
Asset retirement obligations assumed	$ 1,000

Equity Method Investments - Nar

Equity Method Investments - Narrative (Details) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended
	Dec. 31, 2022	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Schedule of Equity Method Investments [Line Items]
Earnings from equity method investments		$ 412,000	$ 0	$ 1,512,000	$ 3,222,000
Tinuum Group, LLC
Schedule of Equity Method Investments [Line Items]
Ownership interest, percent (as percent)	42.50%	42.50%		42.50%
Earnings from equity method investments		$ 200,000	0	$ 1,100,000	3,100,000
Proceeds from equity method investment, percentage share	$ 2,000,000
Liabilities assumed	$ 1,700,000
Initial term	5 years
Automatic renewal term	5 years
Recognized royalty		$ 200,000		600,000
Tinuum Group, LLC | Other Current Liabilities
Schedule of Equity Method Investments [Line Items]
Liabilities assumed	$ 1,700,000			$ 1,700,000
Tinuum Services, LLC
Schedule of Equity Method Investments [Line Items]
Ownership interest, percent (as percent)	50%	50%		50%
Earnings from equity method investments		$ 200,000	$ 0	$ 500,000	$ 100,000

Equity Method Investments - Sch

Equity Method Investments - Schedule of Equity Method Investments (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Schedule of Equity Method Investments [Line Items]
Distributions from equity method investees, return on investment	$ 0	$ 2,297
Distributions from equity method investees in excess of investment basis	1,512	3,316
Tinuum Services
Schedule of Equity Method Investments [Line Items]
Distributions from equity method investees, return on investment	0	2,297
Distributions from equity method investees in excess of investment basis	450	179
Tinuum Group
Schedule of Equity Method Investments [Line Items]
Distributions from equity method investees, return on investment	0	0
Distributions from equity method investees in excess of investment basis	$ 1,062	$ 3,137

Stockholders' Equity (Details)

Stockholders' Equity (Details) $ / shares in Units, $ in Thousands

1 Months Ended

3 Months Ended

9 Months Ended

Jul. 17, 2023 USD ($) $ / shares shares

Apr. 21, 2023 USD ($)

Mar. 31, 2023 shares

Feb. 01, 2023 USD ($) $ / shares shares

Sep. 30, 2023 USD ($) shares

Dec. 31, 2023 USD ($) shares

Mar. 31, 2023 USD ($) shares

Sep. 30, 2023 USD ($)

Sep. 30, 2022 USD ($)

Jul. 14, 2023 member

Jul. 13, 2023 member

Jun. 13, 2023 shares

May 05, 2017

Class of Stock [Line Items]

Paid-in-kind dividend on Series A Preferred Stock | $

$ 200

$ 157

$ 0

Number of board members | member

8

7

Issuance of common stock pursuant to Arq Acquisition, net of offering costs | $

$ 12,437

Issuance of warrant | $

$ 826

Secured Debt

Class of Stock [Line Items]

Issuance of warrant (in shares) | shares

325,857

Issuance of warrant | $

$ 800

President and Chief Executive Officer

Class of Stock [Line Items]

Consideration received on transaction | $

$ 1,800

Price per share (in dollars per share) | $ / shares

$ 1.90

Number of shares agreed to purchase (in shares) | shares

950,000

Maximum

Class of Stock [Line Items]

Requirement to own shares outstanding (as percent)

4.99%

Series A Preferred Stock

Class of Stock [Line Items]

Preferred stock dividends declared on redeemable preferred stock (in shares) | shares

68,464

Arq Acquisition | Series A Preferred Stock

Class of Stock [Line Items]

Issuance of stock upon conversion of preferred stock (in shares) | shares

5,362,926

Common Stock

Class of Stock [Line Items]

Issuance of common stock pursuant to Arq Acquisition, net of offering costs (in shares) | shares

3,842,315

527,779

3,814,864

Consideration received on transaction | $

$ 15,400

Price per share (in dollars per share) | $ / shares

$ 4

Issuance of common stock related to PIPE Investment, net of offering costs (in shares) | shares

3,842,315

Issuance of common stock pursuant to Arq Acquisition, net of offering costs | $

$ 1,000

$ 4

Remaining authorized amount | $

$ 7,000

$ 7,000

Common Stock | Forecast

Class of Stock [Line Items]

Issuance of common stock pursuant to Arq Acquisition, net of offering costs (in shares) | shares

422,221

Issuance of common stock pursuant to Arq Acquisition, net of offering costs | $

$ 800

Common Stock | Arq Acquisition

Class of Stock [Line Items]

Issuance of common stock related to PIPE Investment, net of offering costs (in shares) | shares

3,814,864

Preferred Stock | Arq Acquisition

Class of Stock [Line Items]

Issuance of common stock related to PIPE Investment, net of offering costs (in shares) | shares

5,294,462

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Allocation of Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Stock options granted:
Total stock-based compensation expense	$ 702	$ 507	$ 1,810	$ 1,455
RSA expense
Stock options granted:
Total stock-based compensation expense	501	420	1,405	1,240
PSU expense
Stock options granted:
Total stock-based compensation expense	151	87	355	215
Stock option expense
Stock options granted:
Total stock-based compensation expense	$ 50	$ 0	$ 50	$ 0

Stock-Based Compensation - Sc_2

Stock-Based Compensation - Schedule of Unrecognized Compensation Cost (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2023 USD ($)
Stock options granted:
Unrecognized Compensation Cost	$ 2,904
Expected Weighted- Average Period of Recognition (in years)	2 years 1 month 6 days
RSA expense
Stock options granted:
Unrecognized Compensation Cost	$ 1,723
Expected Weighted- Average Period of Recognition (in years)	1 year 10 months 9 days
PSU expense
Stock options granted:
Unrecognized Compensation Cost	$ 502
Expected Weighted- Average Period of Recognition (in years)	2 years 3 days
Stock option expense
Stock options granted:
Unrecognized Compensation Cost	$ 679
Expected Weighted- Average Period of Recognition (in years)	2 years 9 months 14 days

Stock-Based Compensation - Narr

Stock-Based Compensation - Narrative (Details)	3 Months Ended	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2023
Restricted Stock
Stock options granted:
Vesting period (in years)		3 years
Performance Share Units
Stock options granted:
Vesting period (in years)		3 years
Stock Option
Stock options granted:
Vesting period (in years)		3 years
Options exercisable, weighted average remaining contractual term (in years)		0 years
Dividend yield	0%
Stock Option | Maximum
Stock options granted:
Options exercisable, weighted average remaining contractual term (in years)		10 years

Stock-Based Compensation - Sc_3

Stock-Based Compensation - Schedule of Restricted Stock Activity (Details) - RSA expense	9 Months Ended
	Sep. 30, 2023 $ / shares shares
Restricted Stock
Non-vested shares, beginning balance (in shares) | shares	652,962
Granted (in shares) | shares	773,327
Vested (in shares) | shares	(391,893)
Forfeited (in shares) | shares	(201,271)
Non-vested shares, ending balance (in shares) | shares	833,125
Weighted-Average Grant Date Fair Value
Non-vested shares, beginning balance (in dollars per share) | $ / shares	$ 5.58
Granted (in dollars per share) | $ / shares	1.91
Vested (in dollars per share) | $ / shares	4.89
Forfeited (in dollars per share) | $ / shares	3.29
Non-vested shares, ending balance (in dollars per share) | $ / shares	$ 3.04

Stock-Based Compensation - Sc_4

Stock-Based Compensation - Schedule of Performance Shares Units (Details) - Performance Share Units $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2023 USD ($) $ / shares shares	Sep. 30, 2023 USD ($) $ / shares shares
Units
Non-vested shares, beginning balance (in shares)		148,591
Granted (in shares)		682,709
Vested / Settled (in shares)		0
Forfeited / Canceled (in shares)		(162,382)
Non-vested shares, ending balance (in shares)	668,918	668,918
Weighted-Average Grant Date Fair Value
Non-vested shares, beginning balance (in dollars per share) | $ / shares		$ 7.85
Granted (in dollars per share) | $ / shares		1.22
Vested / Settled (in dollars per share) | $ / shares		0
Forfeited / Canceled (in dollars per share) | $ / shares		4.10
Non-vested shares, ending balance (in dollars per share) | $ / shares	$ 1.99	$ 1.99
Outstanding, aggregate intrinsic value | $	$ 1,191	$ 1,191
Outstanding, weighted-average remaining contractual term (in years)		2 years 3 days
Issued Upon Vesting of PSUs
Units
Vested / Settled (in shares)	0	0

Stock-Based Compensation - Fair

Stock-Based Compensation - Fair Value Assumptions for Options (Details) - Stock option expense - shares	3 Months Ended	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2023
Stock options granted:
Options granted (in shares)	1,000,000	1,000,000
Risk-free interest rate	4%
Dividend yield	0%
Volatility	62%
Expected term (in years)	6 years

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Option Activity (Details) - Stock option expense - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2023	Sep. 30, 2022
Number of Options Outstanding and Exercisable
Options outstanding, start of year (in shares)		0
Options granted (in shares)	1,000,000	1,000,000
Options exercised (in shares)			0
Options expired / forfeited (in shares)		0
Options outstanding, end of year (in shares)	1,000,000	1,000,000
Options vested (in shares)	0	0
Options exercisable (in shares)	0	0
Weighted-Average Exercise Price
Options outstanding, start of year (in dollars per share)		$ 0
Options granted (in dollars per share)		3
Options exercised (in dollars per share)		0
Options expired / forfeited (in dollars per share)		0
Options outstanding, end of year (in dollars per share)	$ 3	$ 3
Options outstanding, intrinsic value	$ 0	$ 0
Options outstanding, weighted average remaining contractual term (in years)		9 years 9 months 14 days
Options vested, weighted average exercise price (in dollars per share)	$ 0	$ 0
Options exercisable, weighted average exercise price (in dollars per share)	$ 0	$ 0
Options vested, intrinsic value	$ 0	$ 0
Options exercisable, intrinsic value	$ 0	$ 0
Options vested, weighted average remaining contractual term (in years)		0 years
Options exercisable, weighted average remaining contractual term (in years)		0 years

Income Taxes - Schedule of Inco

Income Taxes - Schedule of Income Tax Expense and Effective Tax Rates (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Income Tax Disclosure [Abstract]
Income tax benefit	$ 0	$ 0	$ (33)	$ 0
Effective tax rate	0%	0%	0%	0%

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Income Tax Disclosure [Abstract]
Effective tax rate	0%	0%	0%	0%