# Relationship history for MSHA mine 1509870

Current hierarchy: **Hamilton Thelma G & Kerry → Kerry Coal Company Inc → No 1-A Mine (D)**

- 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:** Sloan Curtis & David Belcher → No 1-A Mine (D); 1975-04-22 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Enduro Coal Company Inc → No 1-A Mine (D); 1976-06-01 to 1980-04-13; source msha-controller-operator-history
- **controller_controls_operator:** Sloan Curtis & David Belcher → Enduro Coal Company Inc; 1976-06-01 to 1980-04-13; source msha-controller-operator-history
- **operator_operates_mine:** Kerry Coal Company Inc → No 1-A Mine (D); 1980-04-14 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Hamilton Thelma G & Kerry → No 1-A Mine (D); 1980-04-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hamilton Thelma G & Kerry → Kerry Coal Company Inc; 1980-04-14 to current/open; source msha-controller-operator-history