# Relationship history for MSHA mine 1509595

Current hierarchy: **Ruth David L → Ruth Contracting Corp → No 6 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:** W H  Littan → No 6 Surface; 1973-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Boyd County Coal Co → No 6 Surface; 1976-04-07 to 1978-02-15; source msha-controller-operator-history
- **controller_controls_operator:** W H  Littan → Boyd County Coal Co; 1976-04-07 to 1978-02-15; source msha-controller-operator-history
- **operator_operates_mine:** Ruth Contracting Corp → No 6 Surface; 1978-02-16 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Ruth David L → No 6 Surface; 1978-02-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ruth David L → Ruth Contracting Corp; 1978-02-16 to current/open; source msha-controller-operator-history