# Relationship history for MSHA mine 1507326

Current hierarchy: **Salyers Paul H → Salyers Coal Company → No 1 Surface 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Salyers Coal Company → No 1 Surface Mine; 1974-09-17 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Salyers Paul H → No 1 Surface Mine; 1974-09-17 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Salyers Paul H → Salyers Coal Company; 1974-09-17 to current/open; source msha-controller-operator-history