# Relationship history for MSHA mine 1401592

Current hierarchy: **Gavin  Eales → Calvert USA, LLC → Calvert 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

- **operator_operates_mine:** Calvert Corp → Calvert Mine; 1996-01-01 to 2025-02-28; source msha-controller-operator-history
- **controller_controls_mine:** Bernard  Friedman → Calvert Mine; 1996-01-01 to 2017-03-09; source msha-controller-operator-history
- **controller_controls_operator:** Bernard  Friedman → Calvert Corp; 1996-01-01 to 2017-03-09; source msha-controller-operator-history
- **controller_controls_mine:** Jane  Wessner → Calvert Mine; 2017-03-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Jane  Wessner → Calvert Corp; 2017-03-10 to 2025-02-28; source msha-controller-operator-history
- **operator_operates_mine:** Calvert USA, LLC → Calvert Mine; 2025-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Gavin  Eales → Calvert Mine; 2025-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Gavin  Eales → Calvert USA, LLC; 2025-03-01 to current/open; source msha-controller-operator-history