# Relationship history for MSHA mine 3607485

Current hierarchy: **Zinn Donald → Don Zinn Coal Company → Don 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:** Don Zinn Coal Company → Don Zinn Strip; 1983-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Zinn Donald → Don Zinn Strip; 1983-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Zinn Donald → Don Zinn Coal Company; 1983-08-01 to current/open; source msha-controller-operator-history