‌Exhibit 23.3

582 Industrial Park Road, Bluefield, VA 24605-9364 ■ Phone 276.322.5467 www.mma1.com ■ [email protected]

February 14, 2022

CONSENT OF MARSHALL MILLER & ASSOCIATES, INC.

Mr. Wm. Scott Stewart Arch Resources, Inc.

1 CityPlace Drive, Suite 300 St. Louis, Missouri 63141

Reference: Consent of Independent Experts

With respect to the SEC filings by Arch Resources, Inc., including but not limited to its Annual Report on Form 10-K for the year ended December 31, 2021, we hereby consent (i) to the use of the information contained the Technical Report Summary for Leer South (each, a “TRS”), (ii) ) to the use of Marshall Miller & Associates, Inc.’s name, any quotation from or summarization of the TRS, and (iii) to the filing of the TRS as an exhibit.

We further wish to advise that Marshall Miller & Associates, Inc. was not employed on a contingent basis and that at the time of preparation of our report, as well as at present, neither Marshall Miller & Associates, Inc. nor any of its employees had, or now has, a substantial interest in Arch Resources, Inc. or any of its affiliates or subsidiaries.

Respectfully submitted,

By:/s/

Name:Steven A. Keim Title:President

Date:February 14, 2022

ENERGY & MINERAL RESOURCES ■ HYDROGEOLOGY & GEOLOGY ■ GEOPHYSICAL LOGGING SERVICES

CARBON MANAGEMENT ■ EXPERT WITNESS TESTIMONY ■ MINING ENGINEERING ■ PETROLEUM ENGINEERING