# Relationship history for MSHA mine 2902553

Current hierarchy: **Navajo Nation → NECA → SHill Gravel 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** NECA → SHill Gravel Pit; 2023-11-20 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Navajo Nation → SHill Gravel Pit; 2023-11-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Navajo Nation → NECA; 2023-11-21 to current/open; source msha-controller-operator-history