# Relationship history for MSHA mine 4500725

Current hierarchy: **Woodworth John A → Woodworth & Company Inc → Woodworth Portable Crusher**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Woodworth & Company Inc → Woodworth Portable Crusher; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Woodworth John A → Woodworth Portable Crusher; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Woodworth John A → Woodworth & Company Inc; 1950-01-01 to current/open; source msha-controller-operator-history