# Relationship history for MSHA mine 1401455

Current hierarchy: **Bayer Construction Company Inc → Bayer Construction Company, Inc. → Stevens 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:** Bayer Construction Company Inc → Stevens Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Bayer Construction Company, Inc. → Stevens Quarry; 1985-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bayer Construction Company Inc → Bayer Construction Company, Inc.; 1985-07-01 to current/open; source msha-controller-operator-history