# Relationship history for MSHA mine 1509493

Current hierarchy: **Townley Lynn → B B & T Minerals → 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:** B B & T Minerals → No 1 Surface; 1976-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Townley Lynn → No 1 Surface; 1976-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Townley Lynn → B B & T Minerals; 1976-01-01 to current/open; source msha-controller-operator-history