# Relationship history for MSHA mine 4606696

Current hierarchy: **Carl F  Frischkorn → Battle Ridge Companies → Servco Inc**

- 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:** Carl F  Frischkorn → Servco Inc; 1982-02-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Battle Ridge Companies → Servco Inc; 1983-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Carl F  Frischkorn → Battle Ridge Companies; 1983-09-01 to current/open; source msha-controller-operator-history