# Relationship history for MSHA mine 1700251

Current hierarchy: **Starr Brothers Inc → Starr Brothers Inc → Portable Screen No 55-720**

- 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:** Starr Brothers Inc → Portable Screen No 55-720; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Starr Brothers Inc → Portable Screen No 55-720; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Starr Brothers Inc → Starr Brothers Inc; 1950-01-01 to current/open; source msha-controller-operator-history