# Relationship history for MSHA mine 1511255

Current hierarchy: **Frazier Herbert L → Carolyn Coal Company Inc → No 1 Surface**

- 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:** Carolyn Coal Company Inc → No 1 Surface; 1978-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Frazier Herbert L → No 1 Surface; 1978-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Frazier Herbert L → Carolyn Coal Company Inc; 1978-05-01 to current/open; source msha-controller-operator-history