# Relationship history for MSHA mine 1512924

Current hierarchy: **Salyers Gene & William Stiltner → Thermo Coal Corp → No 57 Mine (D)**

- 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

- **operator_operates_mine:** Thermo Coal Corp → No 57 Mine (D); 1981-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Salyers Gene & William Stiltner → No 57 Mine (D); 1981-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Salyers Gene & William Stiltner → Thermo Coal Corp; 1981-06-01 to current/open; source msha-controller-operator-history