# Relationship history for MSHA mine 3302570

Current hierarchy: **Stewart William → Stewart & Zinn Inc → Stewart & Zinn Strip**

- 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:** Stewart & Zinn Inc → Stewart & Zinn Strip; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Stewart William → Stewart & Zinn Strip; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Stewart William → Stewart & Zinn Inc; 1950-01-01 to current/open; source msha-controller-operator-history