# Relationship history for MSHA mine 3606992

Current hierarchy: **Altmire Brothers Coal Company Inc → Altmire Brothers Coal Company Inc → Balbo 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

- **controller_controls_mine:** Altmire Brothers Coal Company Inc → Balbo Strip; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Altmire Brothers Coal Company Inc → Balbo Strip; 1980-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Altmire Brothers Coal Company Inc → Altmire Brothers Coal Company Inc; 1980-06-01 to current/open; source msha-controller-operator-history