Exhibit 99.1

News from

Arch Coal, Inc.

FOR FURTHER INFORMATION:

Investor Relations

314/994-2897

FOR IMMEDIATE RELEASE

Arch Coal, Inc. Reports Third Quarter 2018 Results

Returns $84 million to shareholders through share repurchases and dividends

Generates highest level of Revenue, Net Income and EBITDA since emergence

Records a 60-percent increase in operating margins in its PRB segment

ST. LOUIS, October 23, 2018 — Arch Coal, Inc. (NYSE: ARCH) today reported net income of $123.2 million, or $6.10 per diluted share, in the third quarter of 2018, compared with net income of $68.4 million, or $2.83 per diluted share, in the prior-year period. Net income of $123.2 million includes a $45.2 million tax benefit. The company earned adjusted earnings before interest, taxes, depreciation, depletion, amortization, accretion on asset retirement obligations, and non-operating expenses (“adjusted EBITDA”) (1) of $124.9 million in the third quarter of 2018, which includes a $10.4 million non-cash mark-to-market loss associated with the company’s coal hedging activities. This compares to $105.1 million of adjusted EBITDA recorded in the third quarter of 2017. Revenues totaled $633.2 million for the three months ended September 30, 2018, representing a 3 percent increase from the prior-year quarter.

“Arch turned in another excellent operating performance in the third quarter, achieving robust coking coal margins, strong cost control in our two thermal segments, and healthy shipment levels at our Powder River Basin operations,” said John W. Eaves, Arch’s chief executive officer. “At the same time, we continued to drive progress in our ongoing capital return program with the repurchase of $76 million of Arch stock. We have now repurchased roughly 25 percent of the company’s total shares outstanding since launching the buy-back program six quarters ago, and intend to maintain that strong forward momentum.”

Capital Allocation Progress

During the third quarter, Arch repurchased nearly 900,000 shares of common stock, representing 3.5 percent of the shares outstanding in May 2017 when the capital return program was launched. Since the program’s inception, Arch has spent a total of $495 million to buy back 6.2 million shares of stock. The board has authorized the expenditure of up to $750 million for share buybacks, leaving $255 million remaining under the current authorization.

(1)  Adjusted EBITDA is defined and reconciled in the “Reconciliation of Non-GAAP measures” in this release.

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“Given our top-tier asset base and our outlook for another strong year of cash generation in 2019, we view our substantial and ongoing buyback program as a highly effective mechanism for enhancing shareholder value,” said John T. Drexler, Arch’s chief financial officer.

Along with the buybacks, Arch returned an additional $7.6 million to shareholders through its recurring quarterly dividend, bringing total dividend payments to $48.4 million since May 2017. The board has now approved the next quarterly cash dividend payment of $0.40 per common share, which is scheduled to be paid on December 14, 2018 to stockholders of record at the close of business on November 30, 2018.

All told, Arch has now returned approximately $544 million to shareholders via share buybacks and dividends over the course of the past six quarters.

Future dividend declarations and share repurchases will be subject to ongoing board review and authorization and will be based on a number of factors, including business and market conditions, Arch’s future financial performance and other capital priorities.

Financial Update

“While we are sharply focused on returning capital to shareholders, we are equally intent on maintaining our industry-leading balance sheet strength,” Drexler said. “We ended the quarter with $408 million of cash and a net cash position — which is defined as cash on the balance sheet in excess of total debt — of $88 million. Going forward, we are targeting maintaining liquidity of around $400 million, which we view as an appropriate and prudent level adequate to serve our future needs regardless of market environment.”

Arch recorded a $45 million tax benefit during the quarter related to the completion of an audit of its alternative minimum tax (AMT) net operating loss carryback claims along with a new tax position taken during the quarter that together increase the company’s available AMT credits. Arch expects to convert the additional AMT credits to cash during the course of the next five years, in keeping with the provisions of the 2017 Tax Cuts and Jobs Act of 2017.

As previously noted, Arch expects its corporate tax rate to be zero for the next 10 years or more.

Operational Results

“Our decision to sell the vast majority of our 2018 coking coal volumes at market-based pricing again proved advantageous during the quarter just ended, and translated into a substantial average margin of approximately $42 per ton for our Metallurgical segment,” said Paul A. Lang, Arch’s president and chief operating officer. “At the same time, we captured excellent margins in both of our thermal segments through effective cost control and robust shipment levels — particularly in the Powder River Basin, where our operations again rose to the challenge by increasing shipments despite the unusually wet summer weather in the region.”

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Coal sales per ton sold and cash cost per ton sold are defined and reconciled under “Reconciliation of non-GAAP measures.”

Mining complexes included in this segment are Beckley, Leer, Lone Mountain, Mountain Laurel and Sentinel.

Lone Mountain is included through September 14, 2017, the date of divestiture.

First nine months 2018 coking coal shipments include 1.0 million tons to North American customers

and approximately 4.8 million tons to seaborne customers.

In the Metallurgical segment, Arch generated strong margins nearly equivalent to those achieved in the previous quarter, despite shipping a higher mix of both High-Vol B coal and North American business fixed in late 2017 at prices well below recent marks.

During the quarter, Arch again demonstrated the highly cost-competitive nature of its metallurgical portfolio. Despite higher material costs stemming from the recent escalation in steel prices, Arch’s Metallurgical segment had an average cost of $62.54 per ton, which the company believes is well below the U.S. industry average for coking coal mines.

Looking ahead, Arch anticipates relatively flat coking coal shipments in the fourth quarter relative to the third quarter, as an improving logistics chain is likely to be counterbalanced by a planned longwall move at the Leer mine and typical export vessel slippage at year-end.

Coal sales per ton sold and cash cost per ton sold are defined and reconciled under “Reconciliation of non-GAAP measures.”

Mining complexes included in this segment are Black Thunder and Coal Creek.

In the Powder River Basin, sales volumes increased by 14 percent versus the second quarter as Arch’s mines benefited from the usual seasonal pick-up in summer demand along with accelerated shipments to several customers. These higher volumes, coupled with effective cost control, helped drive down per-ton costs to $9.76 — an 8-percent reduction from the previous

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quarter. The average per-ton cash margin for the segment increased 61 percent when compared to the second quarter of 2018.

In another significant development, Arch is in the process of finalizing a revision to the mining and reclamation plan at its Black Thunder mine that could result in a $90 million to $110 million reduction, on a discounted basis, in the company’s asset retirement obligation (ARO), and corresponding asset, on its balance sheet. The revised plan would provide for accelerated mine reclamation during the ordinary mining process, and is not expected to increase operating costs. Arch currently expects that this change, along with other routine annual adjustments to the company’s ARO, will be reflected in the company’s year-end financial statements, once all necessary approvals are received and cost estimates are complete.

Looking ahead, the acceleration of shipments that bolstered volumes in the second and third quarters is expected to result in a significant reduction in shipped tons in the fourth quarter of 2018 — and a commensurate increase in unit costs.

Coal sales per ton sold and cash cost per ton sold are defined and reconciled under “Reconciliation of non-GAAP measures.”

Mining complexes included in this segment are Coal-Mac, Viper and West Elk.

In the Other Thermal segment, volumes increased 25 percent versus the previous quarter due in part to an improved logistics chain for exports off the U.S. West Coast. Cash costs decreased 11 percent versus the previous quarter on higher volumes, and the average per-ton cash margin increased 66 percent to $9.28 per ton. Export business represented more than 50 percent of Other Thermal volumes shipped during the third quarter, as Arch continued to take advantage of a strong international marketplace.

Key Market Developments

Coking Coal Markets

·                  Arch believes that coking coal markets remain in healthy balance around the world, buoyed by still-vigorous global economic activity and continuing strength in global steel demand.

·                  Global steel output is up nearly 5 percent year-to-date, according to World Steel Association data.

·                  That growth has helped spur a comparable increase in seaborne coking coal demand through the first eight months of the year.

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·                  Higher quality coking coals such as Arch’s High-Vol A and Low-Vol products are in particularly strong demand as steel producers seek to optimize mill output and capitalize on elevated steel prices.

·                  Coking coal supply is struggling to keep pace with this strong demand profile due to under-investment in mine capacity in recent years along with high-profile operating challenges at several large coking coal operations.

·                  A stressed logistics chain is providing further support to coking coal markets, with long vessel queues and protracted maintenance outages at major export terminals in Australia.

·                  The price of Arch’s primary coking coal product, High-Vol A coal, is currently being assessed at $215 per metric ton for delivery off the U.S. East Coast.

Thermal Coal Markets

·                  Prices in both Pacific Rim and Atlantic Basin markets remain highly supportive of U.S. thermal coal exports, with Australian pricing at nearly $110 per metric ton and European pricing at nearly $100 per metric ton for delivery in 2019.

·                  Those prices continue to provide an attractive netback for exports from Arch’s Other Thermal operations, while inducing overall increases in U.S. exports that are acting to tighten the domestic thermal market.

·                  Arch projects that U.S. thermal exports will increase by more than 30 percent, or 15 million tons, in 2018 versus 2017, and that the export outlook for 2019 is positive as well.

·                  On the domestic front, the U.S. experienced a warmer-than-normal summer, with cooling-degree days nearly 20 percent higher year-over-year.

·                  Those higher temperatures, along with improved natural gas pricing, have helped accelerate the liquidation of U.S. power plant stockpiles, which are currently at the lowest level in four years in terms of days of supply.

·                  Generator solicitations for 2019 delivery have picked up markedly in recent weeks, and increased seaborne demand is boosting prices in those U.S. basins with export options.

During the quarter just ended, Arch signed commitments for roughly 2.9 million tons of coking coal for delivery in 2019. Approximately 1.5 million tons of that total was for delivery to North American customers, with roughly 500,000 tons at a fixed price of $124.44 per ton and the remainder at market-based pricing. The fixed price business for 2019 was approximately $25 per ton higher than the level at which Arch settled North American business last year. In addition, Arch committed 1.4 million tons of coking coal for 2019 delivery to international customers, all at market-based pricing. In total, Arch has now signed commitments for 4.6 million tons of coking coal for delivery in 2019 — roughly 87 percent of which is at market-based pricing.

“With our exceptionally strong balance sheet and expanding international reach, Arch is well-equipped to serve the market’s growing preference for market-based pricing mechanisms,” Lang said. “At the same time, we will continue to lock in business at a fixed price on a highly selective basis — in those instances when we see competitive advantage in doing so and when we can realize the full, undiscounted market value for our products.”

Outlook

“Looking ahead, Arch is well-positioned to capitalize on sustained strength in global coking and

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international thermal markets, while generating solid margins in a tough but improving domestic thermal marketplace,” Eaves said. “We are increasingly enthusiastic about the company’s long-term prospects for profitability and cash generation, and remain sharply focused on creating value for our shareholders through our proven and robust capital return program.”

*Includes approximately 200,000 tons of carryover from 2017

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A conference call regarding Arch Coal’s third quarter 2018 financial results will be webcast live today at 10 a.m. Eastern time. The conference call can be accessed via the “investor” section of the Arch Coal website (http://investor.archcoal.com).

Forward-Looking Statements: This press release contains “forward-looking statements” — that is, statements related to future, not past, events. In this context, forward-looking statements often address our expected future business and financial performance, and often contain words such as “expects,” “anticipates,” “intends,” “plans,” “believes,” “seeks,” or “will.” Forward-looking statements by their nature address matters that are, to different degrees, uncertain. For us, particular uncertainties arise from changes in the demand for our coal by the domestic electric generation and steel industries; from legislation and regulations relating to the Clean Air Act and other environmental initiatives; from operational, geological, permit, labor and weather-related factors; from the Tax Cuts and Jobs Act and other tax reforms; from the effects of foreign and domestic trade policies, actions or disputes; from fluctuations in the amount of cash we generate from operations, which could impact, among other things, our ability to pay dividends or repurchase shares in accordance with our announced capital allocation plan from future integration of acquired businesses; and from numerous other matters of national, regional and global scale, including those of a political, economic, business, competitive or regulatory nature. These uncertainties may cause our actual future results to be materially different than those expressed in our forward-looking statements. We do not undertake to update our forward-looking statements, whether as a result of new information, future events or otherwise, except as may be required by law. For a description of some of the risks and uncertainties that may affect our future results, you should see the risk factors described from time to time in the reports we file with the Securities and Exchange Commission.

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Arch Coal, Inc. and Subsidiaries

Condensed Consolidated Income Statements

(In thousands, except per share data)

(A) Adjusted EBITDA and Adjusted diluted income per common share are defined and reconciled under “Reconciliation of Non-GAAP Measures” later in this release.

Arch Coal, Inc. and Subsidiaries

Condensed Consolidated Balance Sheets

(In thousands)

Arch Coal, Inc. and Subsidiaries

Condensed Consolidated Statements of Cash Flows

(In thousands)

Arch Coal, Inc. and Subsidiaries

Schedule of Consolidated Debt

(In thousands)

Arch Coal, Inc. and Subsidiaries

Operational Performance

(In millions, except per ton data)