# Relationship history for MSHA mine 2200537

Current hierarchy: **Trudie P  Westmoreland → Westmoreland Gravel Company Inc → Grady 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

- **controller_controls_mine:** Trudie P  Westmoreland → Grady Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Grady Contracting Company → Grady Pit; 1981-06-01 to 1986-06-12; source msha-controller-operator-history
- **controller_controls_mine:** Grady Van → Grady Pit; 1981-06-01 to 1986-06-12; source msha-controller-operator-history
- **controller_controls_operator:** Grady Van → Grady Contracting Company; 1981-06-01 to 1986-06-12; source msha-controller-operator-history
- **operator_operates_mine:** Westmoreland Gravel Company Inc → Grady Pit; 1986-06-13 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Trudie P  Westmoreland → Westmoreland Gravel Company Inc; 1986-06-13 to current/open; source msha-controller-operator-history