---
schema_version: "secwatch.filing_event.v1"
accession: "0001710366-26-000045"
form_type: "8-K"
ticker: "CNR"
cik: "0001710366"
company_name: "Core Natural Resources, Inc."
filed_at: "2026-05-19T20:02:02+00:00"
generated_at: "2026-05-19T20:03:13.813065+00:00"
event_type: "regulatory"
sentiment: "neutral"
materiality_score: 0.1
calibrated_materiality_score: 0.1
confidence: "high"
source: SEC EDGAR
---

# Core Natural Resources receives vacated MSHA imminent danger order at Leer South mine

## Summary
- Wolf Run Mining LLC subsidiary received 107(a) order on May 13, 2026 for elevated methane at Leer South (Barbour County, WV).
- MSHA terminated the order early on May 14, 2026 after corrective actions.
- On May 18, 2026, MSHA determined no imminent danger had ever existed and vacated the order.
- No production impact or penalties disclosed beyond the reporting requirement.

## SEC filing metadata
- accession: 0001710366-26-000045
- form_type: 8-K
- ticker: CNR
- cik: 0001710366
- company_name: Core Natural Resources, Inc.
- filed_at: 2026-05-19T20:02:02+00:00
- event_type: regulatory
- sentiment: neutral
- materiality_score: 0.1
- calibrated_materiality_score: 0.1
- confidence: high
- sec_items: 1.04
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1710366/000171036626000045/0001710366-26-000045-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1710366/000171036626000045/cnr-20260513.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001710366-26-000045
- JSON: https://secwatch.observer/filing/0001710366-26-000045.json
- Plain text: https://secwatch.observer/filing/0001710366-26-000045.txt

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.