# Relationship history for MSHA mine 5001889

Current hierarchy: **Orion Marine Group Inc → Orion Marine Contractors → Unisea 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Bradley K  West → Unisea Quarry; 2003-04-17 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** West Construction Company → Unisea Quarry; 2008-06-27 to 2016-02-15; source msha-controller-operator-history
- **controller_controls_operator:** Bradley K  West → West Construction Company; 2008-06-27 to 2016-02-15; source msha-controller-operator-history
- **controller_controls_mine:** Orion Marine Group Inc → Unisea Quarry; 2014-10-07 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Orion Marine Contractors → Unisea Quarry; 2016-02-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Orion Marine Group Inc → Orion Marine Contractors; 2016-02-16 to current/open; source msha-controller-operator-history