# Relationship history for MSHA mine 2302353

Current hierarchy: **Doug  Black → Semco Stone → Blue River 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:** Edward J  Robinson → Blue River Quarry; 1999-07-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Semco Stone → Blue River Quarry; 2006-12-21 to 2023-07-26; source msha-controller-operator-history
- **controller_controls_operator:** Edward J  Robinson → Semco Stone; 2006-12-21 to 2023-07-26; source msha-controller-operator-history
- **operator_operates_mine:** Semco Stone → Blue River Quarry; 2023-07-27 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Doug  Black → Blue River Quarry; 2023-07-27 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Doug  Black → Semco Stone; 2023-07-27 to current/open; source msha-controller-operator-history