# Relationship history for MSHA mine 3602190

Current hierarchy: **Walacavage Walter & Bruce Fishburn → W & F Coal Company → W And F Drift**

- 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:** Marion Mining Company Inc → W And F Drift; 1950-01-01 to 1981-04-12; source msha-controller-operator-history
- **controller_controls_mine:** Marion Mining Company Inc → W And F Drift; 1950-01-01 to 1981-04-12; source msha-controller-operator-history
- **controller_controls_operator:** Marion Mining Company Inc → Marion Mining Company Inc; 1950-01-01 to 1981-04-12; source msha-controller-operator-history
- **operator_operates_mine:** W & F Coal Company → W And F Drift; 1981-04-13 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Walacavage Walter & Bruce Fishburn → W And F Drift; 1981-04-13 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Walacavage Walter & Bruce Fishburn → W & F Coal Company; 1981-04-13 to current/open; source msha-controller-operator-history