# Relationship history for MSHA mine 0101910

Current hierarchy: **Simmons George M → Berry Mountain Mining Company Inc → Walkers Gap 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Battle Creek Mining Company Inc → Walkers Gap Mine; 1978-08-01 to 1983-12-20; source msha-controller-operator-history
- **controller_controls_mine:** Calvert John D → Walkers Gap Mine; 1978-08-01 to 1983-12-20; source msha-controller-operator-history
- **controller_controls_operator:** Calvert John D → Battle Creek Mining Company Inc; 1978-08-01 to 1983-12-20; source msha-controller-operator-history
- **controller_controls_mine:** Simmons George M → Walkers Gap Mine; 1983-06-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Berry Mountain Mining Company Inc → Walkers Gap Mine; 1983-12-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Simmons George M → Berry Mountain Mining Company Inc; 1983-12-21 to current/open; source msha-controller-operator-history