# Relationship history for MSHA mine 1510858

Current hierarchy: **Francis Robert L → Barbara Kay Coal Corp → No 1 Mine**

- 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:** Francis Robert L → No 1 Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Barbara Kay Coal Corp → No 1 Mine; 1977-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Francis Robert L → Barbara Kay Coal Corp; 1977-11-01 to current/open; source msha-controller-operator-history