# Relationship history for MSHA mine 4201882

Current hierarchy: **Isford A A → Crater Exploration Inc → Nancy 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:** Isford A A → Nancy Mine; 1984-01-12 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Crater Exploration Inc → Nancy Mine; 1984-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Isford A A → Crater Exploration Inc; 1984-05-01 to current/open; source msha-controller-operator-history