# Relationship history for MSHA mine 4201277

Current hierarchy: **Clyde W C → W W Clyde & Company → Emery Test Pit**

- 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:** W W Clyde & Company → Emery Test Pit; 1976-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Clyde W C → Emery Test Pit; 1976-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Clyde W C → W W Clyde & Company; 1976-02-01 to current/open; source msha-controller-operator-history