# Relationship history for MSHA mine 3605907

Current hierarchy: **Lewis Richard A & Arthur L → Spruce Hill Coal Company → Spruce Hill Coal & Auger No 1 Mine**

- 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:** Spruce Hill Coal Company → Spruce Hill Coal & Auger No 1 Mine; 1975-12-15 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Lewis Richard A & Arthur L → Spruce Hill Coal & Auger No 1 Mine; 1975-12-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Lewis Richard A & Arthur L → Spruce Hill Coal Company; 1975-12-15 to current/open; source msha-controller-operator-history