# Relationship history for MSHA mine 1507624

Current hierarchy: **Mc Erlean Edward T → Bally 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **controller_controls_mine:** Tyra William → No 1 Surface; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Tyra Coal Co Inc → No 1 Surface; 1974-11-03 to 1978-06-06; source msha-controller-operator-history
- **controller_controls_operator:** Tyra William → Tyra Coal Co Inc; 1974-11-03 to 1978-06-06; source msha-controller-operator-history
- **operator_operates_mine:** Bally Coal Company Inc → No 1 Surface; 1978-06-07 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Mc Erlean Edward T → No 1 Surface; 1978-06-07 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mc Erlean Edward T → Bally Coal Company Inc; 1978-06-07 to current/open; source msha-controller-operator-history