# Relationship history for MSHA mine 1800642

Current hierarchy: **Ridgecrest Energy Company → Garbart Coal Company Inc → Strip 12**

- 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:** Garbart Paul L → Strip 12; 1950-01-01 to 1979-11-30; source msha-controller-operator-history
- **operator_operates_mine:** Appalachian Construction Company → Strip 12; 1977-04-01 to 1977-07-11; source msha-controller-operator-history
- **controller_controls_mine:** Snyder Atlee R → Strip 12; 1977-04-01 to 1977-07-11; source msha-controller-operator-history
- **controller_controls_operator:** Snyder Atlee R → Appalachian Construction Company; 1977-04-01 to 1977-07-11; source msha-controller-operator-history
- **operator_operates_mine:** Garbart Coal Company Inc → Strip 12; 1977-07-12 to 1979-04-26; source msha-controller-operator-history
- **controller_controls_operator:** Garbart Paul L → Garbart Coal Company Inc; 1977-07-12 to 1979-04-26; source msha-controller-operator-history
- **operator_operates_mine:** Garbart Coal Company Inc → Strip 12; 1979-04-27 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Ridgecrest Energy Company → Strip 12; 1979-04-27 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ridgecrest Energy Company → Garbart Coal Company Inc; 1979-04-27 to current/open; source msha-controller-operator-history