Core Natural Resources, Inc.

Disclosure Controls and Procedures

Core Natural Resources, under the supervision and with the participation of its management, including Core's principal executive officer and principal financial officer, evaluated the effectiveness of the Company's “disclosure controls and procedures,” as such term is defined in Rule 13a-15(e) under the Exchange Act, as of the end of the period covered by this Quarterly Report on Form 10-Q. Based on that evaluation, Core Natural Resources' principal executive officer and principal financial officer have concluded that the Company's disclosure controls and procedures were effective as of September 30, 2025 to ensure that information required to be disclosed by Core Natural Resources in reports that it files or submits under the Exchange Act is recorded, processed, summarized and reported within the time periods specified in SEC rules and forms, and includes controls and procedures designed to ensure that information required to be disclosed by Core Natural Resources in such reports is accumulated and communicated to Core's management, including Core's principal executive officer and principal financial officer, as appropriate to allow timely decisions regarding required disclosure.

Changes in Internal Control over Financial Reporting

Under SEC guidelines, companies are permitted to exclude acquisitions from their assessment of internal control over financial reporting during the first year following an acquisition while integrating the acquired company. During the first quarter of 2025, we completed the Merger and began integrating the acquired assets into our internal control over financial reporting. We have excluded the acquired operations of Arch from our assessment of the Company's internal control over financial reporting but will continue to evaluate and monitor our internal control over financial reporting and will continue to evaluate the operating effectiveness of related key controls. Arch constituted approximately 51% and 49% of total revenues for the three and nine months ended September 30, 2025, respectively, and approximately 55% of total assets as of September 30, 2025.

Except as noted above, there were no changes in the Company's internal control over financial reporting, as such term is defined in Rule 13a-15(f) of the Exchange Act, that occurred during the third quarter of 2025 that materially affected, or are reasonably likely to materially affect, the Company’s internal control over financial reporting.

It should be noted that any system of controls, however well designed and operated, can provide only reasonable, and not absolute, assurance that the objectives of the system will be met. In addition, the design of any control system is based in part upon certain assumptions about the likelihood of future events.