# Relationship history for MSHA mine 3502623

Current hierarchy: **George J  Williamson → C J Excavating → LIGHTHOUSE 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

- **controller_controls_mine:** Creson W T → LIGHTHOUSE QUARRY; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Tillamook County Road Department → LIGHTHOUSE QUARRY; 1950-01-01 to 1978-09-15; source msha-controller-operator-history
- **controller_controls_mine:** Tillamook County - Or → LIGHTHOUSE QUARRY; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Tillamook County - Or → Tillamook County Road Department; 1950-01-01 to 1978-09-15; source msha-controller-operator-history
- **operator_operates_mine:** Crown Zellerbach Corp → LIGHTHOUSE QUARRY; 1978-09-16 to 1999-10-04; source msha-controller-operator-history
- **controller_controls_operator:** Creson W T → Crown Zellerbach Corp; 1978-09-16 to 1999-10-04; source msha-controller-operator-history
- **operator_operates_mine:** C J Excavating → LIGHTHOUSE QUARRY; 1999-10-05 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** George J  Williamson → LIGHTHOUSE QUARRY; 1999-10-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** George J  Williamson → C J Excavating; 1999-10-05 to current/open; source msha-controller-operator-history