# Relationship history for MSHA mine 4503412

Current hierarchy: **David  Williamson → Horseshoe Bend Quarry → Horseshoe Bend Quarry**

- 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:** Horseshoe Bend Quarry → Horseshoe Bend Quarry; 1999-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Ken R  Williamson → Horseshoe Bend Quarry; 1999-09-01 to 2025-07-09; source msha-controller-operator-history
- **controller_controls_operator:** Ken R  Williamson → Horseshoe Bend Quarry; 1999-09-01 to 2025-07-09; source msha-controller-operator-history
- **controller_controls_mine:** David  Williamson → Horseshoe Bend Quarry; 2025-07-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** David  Williamson → Horseshoe Bend Quarry; 2025-07-10 to current/open; source msha-controller-operator-history