# Relationship history for MSHA mine 4502788

Current hierarchy: **Spokane County - Wa → Spokane County Road Department → Cleveland 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:** N A Degerstrom → Cleveland Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Spokane County - Wa → Cleveland Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** N A Degerstrom Inc → Cleveland Quarry; 1980-02-01 to 1981-01-12; source msha-controller-operator-history
- **controller_controls_operator:** N A Degerstrom → N A Degerstrom Inc; 1980-02-01 to 1981-01-12; source msha-controller-operator-history
- **operator_operates_mine:** Spokane County Road Department → Cleveland Quarry; 1981-01-13 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Spokane County - Wa → Spokane County Road Department; 1981-01-13 to current/open; source msha-controller-operator-history