# Relationship history for MSHA mine 1517776

Current hierarchy: **Zeigler Coal Holding Company → Clark Elkhorn Coal Company → Ratliff Mine No 111**

- 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:** Zeigler Coal Holding Company → Ratliff Mine No 111; 1992-11-23 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Clark Elkhorn Coal Company → Ratliff Mine No 111; 1996-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Zeigler Coal Holding Company → Clark Elkhorn Coal Company; 1996-04-01 to current/open; source msha-controller-operator-history