# Relationship history for MSHA mine 2401566

Current hierarchy: **Crystal Northwest Mines Inc → C N W Operations Inc → Crystal**

- 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:** Bullock Allan → Crystal; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Bullock Brothers Inc → Crystal; 1980-06-01 to 1981-11-16; source msha-controller-operator-history
- **controller_controls_operator:** Bullock Allan → Bullock Brothers Inc; 1980-06-01 to 1981-11-16; source msha-controller-operator-history
- **operator_operates_mine:** C N W Operations Inc → Crystal; 1981-11-17 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Crystal Northwest Mines Inc → Crystal; 1981-11-17 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Crystal Northwest Mines Inc → C N W Operations Inc; 1981-11-17 to current/open; source msha-controller-operator-history