# Relationship history for MSHA mine 4503083

Current hierarchy: **Whitman County - Wa → Whitman County Public Work Department → Union Center 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:** Whitman County Public Work Department → Union Center Quarry; 1986-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Whitman County - Wa → Union Center Quarry; 1986-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Whitman County - Wa → Whitman County Public Work Department; 1986-05-01 to current/open; source msha-controller-operator-history