# Relationship history for MSHA mine 0503672

Current hierarchy: **Core Natural Resources Inc → Mountain Coal Company, L.L.C. → West Elk Mine**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **controller_controls_mine:** Atlantic Richfield Company → West Elk Mine; 1980-03-05 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Mountain Coal Company → West Elk Mine; 1981-04-01 to 1998-03-22; source msha-controller-operator-history
- **controller_controls_operator:** Atlantic Richfield Company → Mountain Coal Company; 1981-04-01 to 1998-03-22; source msha-controller-operator-history
- **operator_operates_mine:** Mountain Coal Company, L.L.C. → West Elk Mine; 1998-03-23 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Arch Resources Inc → West Elk Mine; 1998-03-23 to 2025-01-13; source msha-controller-operator-history
- **controller_controls_operator:** Arch Resources Inc → Mountain Coal Company, L.L.C.; 1998-03-23 to 2025-01-13; source msha-controller-operator-history
- **controller_controls_mine:** Core Natural Resources Inc → West Elk Mine; 2025-01-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Core Natural Resources Inc → Mountain Coal Company, L.L.C.; 2025-01-14 to current/open; source msha-controller-operator-history