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 outlined below, during the three months ended March 31, 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 March 2, 2026, Robert J. Braithwaite, Senior Vice President, Marketing and Sales, adopted a Rule 10b5-1 trading arrangement for the sale of up to 4,500 shares of our common stock, subject to certain conditions. The arrangement’s expiration date is June 2, 2027, for a duration of 458 days.

•On March 5, 2026, Kurt R. Salvatori, Senior Vice President, Chief Administrative Officer, adopted a Rule 10b5-1 trading arrangement for the sale of up to 11,265 shares of our common stock, subject to certain conditions. The arrangement’s expiration date is June 7, 2027, for a duration of 460 days.

•On March 20, 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 November 30, 2026, for a duration of 256 days.

•On March 25, 2026, Rosemary L. Klein, Senior Vice President, Chief Legal Officer and Corporate Secretary, adopted a Rule 10b5-1 trading arrangement for the sale of up to 7,500 shares of our common stock, subject to certain conditions. The arrangement’s expiration date is June 24, 2027, for a duration of 457 days.