# Relationship history for MSHA mine 0203278

Current hierarchy: **Coconino County-Az → Coconino County Public Works Dept. → Portable Screen All**

- 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:** Coconino County-Az → Portable Screen All; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Coconino County Public Works Dept. → Portable Screen All; 2011-05-17 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Coconino County-Az → Coconino County Public Works Dept.; 2011-05-17 to current/open; source msha-controller-operator-history