# Relationship history for MSHA mine 3303346

Current hierarchy: **Zelek Frank → Zelek Coal Company → Carol 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Zelek Coal Company → Carol Strip; 1975-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Zelek Frank → Carol Strip; 1975-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Zelek Frank → Zelek Coal Company; 1975-08-01 to current/open; source msha-controller-operator-history