# Relationship history for MSHA mine 4405891

Current hierarchy: **Metec Acquisition Corp → Coal Systems Ltd → Mine 122**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **controller_controls_mine:** Metec Acquisition Corp → Mine 122; 1979-09-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Coal Systems Ltd → Mine 122; 1982-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Metec Acquisition Corp → Coal Systems Ltd; 1982-08-01 to current/open; source msha-controller-operator-history