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. During the three months ended December 31, 2025, no director or officer of the Company adopted or terminated 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.

Severance Agreements

On February 16, 2026, we entered into a Severance Agreement (each, a “Severance Agreement”) with each of our current executive officers, including our named executive officers, consisting of Mr. Brock, Mr. Thakkar, Mr. Braithwaite, Ms. Klein, Mr. Salvatori, Mr. Schuller and Mr. Slone.

Pursuant to the Severance Agreements, if we terminate the executive officer without “cause” or if such executive officer resigns for “good reason” (each as defined in the Severance Agreements) (a “qualifying termination”) outside of the CIC Protection Period (as defined below), and subject to the executive officer signing and not revoking a general release of claims in favor of the Company and continued compliance with certain confidentiality and post-termination restrictive covenants, the executive officer would be entitled to receive (i) an amount in cash equal to 1.5-2.0 times the executive officer’s annual base salary (2.0-3.0 times in the CIC Protection Period); (ii) to the extent unpaid, the annual bonus earned for the year prior to the year of termination, based on actual performance (with any metric based on individual performance based on the higher of actual performance and target); (iii) a pro-rated portion of the annual bonus for the year of termination based on actual performance for the year (with any metric based on individual performance based on the higher of actual performance and target); (iv) an amount in cash equal to 1.5-2.0 times (2.0-3.0 times in the CIC Protection Period) the higher of (x) the executive officer’s most recent annual bonus, (y) the average annual bonus for the three years preceding the date of termination and (z) the executive officer’s target annual bonus; (v) a cash payment equal to 12 -18 times the executive officer’s applicable monthly COBRA rate (18 times in the CIC Protection Period); (vi) a cash payment equal to 12-24 times the executive officer’s applicable monthly life insurance premium rate (24-36 times in the CIC Protection Period); (vii) the matching contribution under our 401(k) plan as if the executive officer continued to participate in the plan for a period of 12-24 months (24-36 months in the CIC Protection Period); (viii) $25,000 for outplacement services; (ix) payout for any unused vacation time; and (x) all unvested equity awards under any of our equity compensation plans will be governed by the terms of the applicable award agreement, except during the CIC Protection Period, all unvested equity awards under any of our equity compensation plans that were granted prior to the change in control shall become 100% vested as to any service or time-vesting component. In addition, if the executive officer experiences a qualifying termination during the CIC Protection Period, the executive officer would also be entitled to receive the matching contribution under our nonqualified deferred compensation restoration plan as if the executive officer continued to participate in the plan for a period of 18 months. The “CIC Protection Period” is the period beginning three months prior to the date of a “change in control” (as defined in the Severance Agreements) and ending on (and including) the two-year anniversary of the date of a change in control.

The Severance Agreements contain confidentiality provisions for the benefit of the Company and post-termination restrictive covenants that prohibit the executive officers from competing with us for a period of up to 12 months following termination or soliciting our employees for a period of up to three months following termination.

The Severance Agreements do not supersede any prior employment, severance or change in control agreement between any executive officer and the Company or any of its affiliates (including Arch Resources, Inc.) with respect to the executive officer’s termination of employment that occurs on or within two years following the Merger. If the executive officer is a party to any such agreement, their Severance Agreement will only become effective upon the expiration of two years following the Merger.

The above description is qualified in its entirety by reference to the Severance Agreements, the form of which is filed as Exhibit 10.72 hereto and is incorporated herein by reference.