# Relationship history for MSHA mine 4406637

Current hierarchy: **Westmoreland Coal Company → Westmoreland Coal Company → Beechwood 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:** Westmoreland Coal Company → Beechwood Mine #; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Westmoreland Coal Company → Beechwood Mine #; 1991-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Westmoreland Coal Company → Westmoreland Coal Company; 1991-04-01 to current/open; source msha-controller-operator-history