# Relationship history for MSHA mine 1508622

Current hierarchy: **Denny Fred-D C Simpson → D & S Coal Company Inc → D & S No 1 Strip**

- 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:** D & S Coal Company Inc → D & S No 1 Strip; 1975-07-14 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Denny Fred-D C Simpson Et Al → D & S No 1 Strip; 1975-07-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Denny Fred-D C Simpson Et Al → D & S Coal Company Inc; 1975-07-14 to current/open; source msha-controller-operator-history