# Relationship history for MSHA mine 1508803

Current hierarchy: **Ashworth Frank → A & C Mining Company Inc → 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** A & C Mining Company Inc → No 1 Mine; 1975-09-11 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Ashworth Frank → No 1 Mine; 1975-09-11 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ashworth Frank → A & C Mining Company Inc; 1975-09-11 to current/open; source msha-controller-operator-history