# Relationship history for MSHA mine 1509735

Current hierarchy: **Osborne Stanley & Lester L → Sunny Ridge Mining Company → 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Sunny Ridge Mining Company → No 1 Mine; 1976-06-08 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Osborne Stanley & Lester L → No 1 Mine; 1976-06-08 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Osborne Stanley & Lester L → Sunny Ridge Mining Company; 1976-06-08 to current/open; source msha-controller-operator-history