# Relationship history for MSHA mine 1515121

Current hierarchy: **Shortridge Keaster → Black Hole Mining Of Old Kentucky Inc → Black Hole No 4**

- 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

- **operator_operates_mine:** Key Coal Company Inc → Black Hole No 4; 1985-03-01 to 1985-10-09; source msha-controller-operator-history
- **controller_controls_mine:** Barton Delmar → Black Hole No 4; 1985-03-01 to 1985-10-09; source msha-controller-operator-history
- **controller_controls_operator:** Barton Delmar → Key Coal Company Inc; 1985-03-01 to 1985-10-09; source msha-controller-operator-history
- **controller_controls_mine:** Shortridge Keaster Et Al → Black Hole No 4; 1985-06-28 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Black Hole Mining Of Old Kentucky Inc → Black Hole No 4; 1985-10-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Shortridge Keaster Et Al → Black Hole Mining Of Old Kentucky Inc; 1985-10-10 to current/open; source msha-controller-operator-history