# Relationship history for MSHA mine 1507323

Current hierarchy: **Endicott Shelby R → Ro-Ann Mining Inc → No 13**

- 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:** Salmons Coal Company → No 13; 1950-01-01 to 1987-01-06; source msha-controller-operator-history
- **controller_controls_mine:** Salmons Vernie → No 13; 1950-01-01 to 1987-01-06; source msha-controller-operator-history
- **controller_controls_operator:** Salmons Vernie → Salmons Coal Company; 1950-01-01 to 1987-01-06; source msha-controller-operator-history
- **operator_operates_mine:** Ro-Ann Mining Inc → No 13; 1987-01-07 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Endicott Shelby R → No 13; 1987-01-07 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Endicott Shelby R → Ro-Ann Mining Inc; 1987-01-07 to current/open; source msha-controller-operator-history