Core Natural Resources (NYSE: CNR) reports and resolves mine safety order

Rhea-AI Filing Summary

Core Natural Resources, Inc. reported a mine safety event at its Mountaineer II mine in Logan County, West Virginia. On January 8, 2026, subsidiary Mingo Logan Coal LLC received an imminent danger order under section 107(a) of the Federal Mine Safety and Health Act of 1977 after an inspector found elevated methane levels in an isolated section of the mine. Mine personnel took actions to correct the issue and restored acceptable methane levels. The Mine Safety and Health Administration subsequently terminated the 107(a) order, and no injuries or illnesses resulted from this temporary condition.

Insights

Mining safety and ESG analyst

Regulators issued, then terminated, an imminent danger order with no injuries.

Core Natural Resources disclosed that its subsidiary Mingo Logan Coal LLC received an imminent danger order under section 107(a) at the Mountaineer II mine due to elevated methane levels in an isolated area. Such orders require operations in the affected area to cease until the hazard is addressed, reflecting strict federal oversight of underground mine conditions.

The company states that mine personnel took steps to alleviate the methane condition and restored acceptable levels, after which the Mine Safety and Health Administration terminated the order. The disclosure also notes that no injuries or illnesses were associated with this incident, which limits immediate operational and liability concerns based on the available information.

For investors focused on safety and environmental, social, and governance factors, this event highlights regulatory scrutiny around methane management at Mountaineer II. Future company disclosures about mine safety performance and any recurring patterns of violations, if they occur, would be relevant for assessing operational risk and compliance culture.

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d) OF THE

SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported): January 8, 2026

Core Natural Resources, Inc.

(Exact name of registrant as specified in its charter)

Delaware

001-38147

82-1954058

(State or other jurisdiction of incorporation)

(Commission File Number)

(IRS Employer Identification No.)

275 Technology Drive Suite 101

Canonsburg, Pennsylvania 15317

(Address of principal executive offices)

(Zip code)

Registrant's telephone number, including area code:

(724) 416-8300

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class			Trading Symbol(s)			Name of each exchange on which registered
Common Stock, $0.01 par value			CNR			New York Stock Exchange

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 1.04 Mine Safety – Reporting of Shutdowns and Patterns of Violations.

On January 8, 2026, Mingo Logan Coal LLC, a subsidiary of Core Natural Resources, Inc., received an imminent danger order under section 107(a) of the Federal Mine Safety and Health Act of 1977 at the Mountaineer II mine located in Logan County, West Virginia. The order states that an inspector found an accumulation of elevated methane levels in an isolated section of the mine. Mine personnel promptly took appropriate actions to alleviate the condition and restored acceptable methane levels. The Mine Safety and Health Administration has terminated the 107(a) order, and no injuries or illnesses resulted from the temporary condition.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

			Core Natural Resources, Inc.
			(Registrant)
			By:			/s/ MITESHKUMAR B. THAKKAR
						Miteshkumar B. Thakkar
						Chief Financial Officer and President

Date: January 12, 2026

FAQ

What mine safety incident did Core Natural Resources (CNR) report at Mountaineer II?

Core Natural Resources reported that its subsidiary Mingo Logan Coal LLC received an imminent danger order under section 107(a) of the Federal Mine Safety and Health Act of 1977 at the Mountaineer II mine in Logan County, West Virginia, after an inspector found elevated methane levels in an isolated section.

Were there any injuries or illnesses from the methane issue reported by CNR?

No. The company states that no injuries or illnesses resulted from the temporary methane condition that triggered the section 107(a) imminent danger order at the Mountaineer II mine.

How was the imminent danger order at CNR's Mountaineer II mine resolved?

Mine personnel at Mingo Logan Coal LLC took actions to alleviate the elevated methane levels and restored acceptable methane levels in the affected section. Following this, the Mine Safety and Health Administration terminated the section 107(a) order.

When did Mingo Logan Coal LLC receive the section 107(a) imminent danger order?

The imminent danger order under section 107(a) was received on January 8, 2026 by Mingo Logan Coal LLC, a subsidiary of Core Natural Resources, Inc.

Which subsidiary of Core Natural Resources was involved in the mine safety order?

The mine safety order involved Mingo Logan Coal LLC, a subsidiary of Core Natural Resources, Inc., operating the Mountaineer II mine in Logan County, West Virginia.

What law governed the imminent danger order reported by Core Natural Resources?

The imminent danger order was issued under section 107(a) of the Federal Mine Safety and Health Act of 1977, which allows regulators to act when conditions in a mine pose an imminent danger.