# Relationship history for MSHA mine 0504249

Current hierarchy: **Hess Alton → Sunnyside Gravel & Excavation → Sunnyside Pit**

- 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:** Sunnyside Gravel & Excavation → Sunnyside Pit; 1987-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Hess Alton → Sunnyside Pit; 1987-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hess Alton → Sunnyside Gravel & Excavation; 1987-08-01 to current/open; source msha-controller-operator-history