# Relationship history for MSHA mine 2302160

Current hierarchy: **David E  Bailey → Bailey Quarries Inc → SPENCER 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:** David E  Bailey  et al → SPENCER QUARRY; 1985-04-03 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Bailey Quarries Inc → SPENCER QUARRY; 1997-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** David E  Bailey  et al → Bailey Quarries Inc; 1997-09-01 to current/open; source msha-controller-operator-history