# Relationship history for MSHA mine 4606374

Current hierarchy: **Wymer William O → Ames 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:** Wheeling-Pittsburgh Corp → No 1 Surface; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** W-P Coal Company → No 1 Surface; 1981-08-01 to 1981-11-15; source msha-controller-operator-history
- **controller_controls_operator:** Wheeling-Pittsburgh Corp → W-P Coal Company; 1981-08-01 to 1981-11-15; source msha-controller-operator-history
- **operator_operates_mine:** Ames Coal Company Inc → No 1 Surface; 1981-11-16 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Wymer William O → No 1 Surface; 1981-11-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Wymer William O → Ames Coal Company Inc; 1981-11-16 to current/open; source msha-controller-operator-history