# Relationship history for MSHA mine 1201610

Current hierarchy: **Hopf Kenneth J → Hopf Energy Inc → Hopf Energy Inc Surface**

- 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:** Steftenagel Sylvester → Hopf Energy Inc Surface; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Steftenagel Coal Company → Hopf Energy Inc Surface; 1977-10-01 to 1978-01-31; source msha-controller-operator-history
- **controller_controls_operator:** Steftenagel Sylvester → Steftenagel Coal Company; 1977-10-01 to 1978-01-31; source msha-controller-operator-history
- **operator_operates_mine:** Hopf Energy Inc → Hopf Energy Inc Surface; 1978-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Hopf Kenneth J → Hopf Energy Inc Surface; 1978-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hopf Kenneth J → Hopf Energy Inc; 1978-02-01 to current/open; source msha-controller-operator-history