# Relationship history for MSHA mine 1517178

Current hierarchy: **Johnson Donald → Federal Mining Company Inc → #2 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **controller_controls_mine:** Johnson Donald → #2 Mine; 1982-06-09 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Federal Mining Company Inc → #2 Mine; 1992-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Johnson Donald → Federal Mining Company Inc; 1992-01-01 to current/open; source msha-controller-operator-history