# Relationship history for MSHA mine 4405776

Current hierarchy: **Darrell L  Boyd → Double D Coal Company Inc → No 9**

- 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:** Darrell L  Boyd → No 9; 1974-08-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Double D Coal Company Inc → No 9; 1981-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Darrell L  Boyd → Double D Coal Company Inc; 1981-10-01 to current/open; source msha-controller-operator-history