# Relationship history for MSHA mine 4702685

Current hierarchy: **Iron County-Wi → Iron County Highway Department → Tomak Pit**

- 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

- **controller_controls_mine:** Iron County-Wi → Tomak Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Iron County Highway Department → Tomak Pit; 1980-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Iron County-Wi → Iron County Highway Department; 1980-07-01 to current/open; source msha-controller-operator-history