Core Natural Resources, Inc.

Rule 10b5-1 Trading Plans

Our executive officers and directors may from time to time enter into plans or arrangements for the purchase or sale of our common stock that are intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act. Except as described below, during the three months ended September 30, 2026, no director or officer of the Company adopted orterminated a “Rule 10b5-1 trading arrangement” or “non-Rule 10b5-1 trading arrangement,” as each term is defined in Item 408 of Regulation S-K:

•On August 18, 2026, George J. Schuller, Jr., Senior Vice President and Chief Operating Officer, adopted a Rule 10b5-1 trading arrangement for the sale of up to 27,100 shares of our common stock, subject to certain conditions. The number of shares represents the maximum number of shares that could potentially be sold pursuant to the Rule 10b5-1 trading arrangement, including sales made in connection with the vesting of future equity awards. Accordingly, in calculating this amount, we have not considered any potential reductions in shares available to be sold due to tax withholdings at the time such equity awards vest, and, for performance-based awards, we have assumed such awards will vest at maximum value. The arrangement’s expiration date is August 17, 2027, for a duration of 365 days.

•On August 31, 2026, James A. Brock, Chair and Chief Executive Officer, adopted a Rule 10b5-1 trading arrangement for the sale of up to 100,000 shares of our common stock, subject to certain conditions. The arrangement’s expiration date is May 28, 2027, for a duration of 271 days.