# Relationship history for MSHA mine 1503244

Current hierarchy: **Call & Ramsey → Pounding Mill Coal Co Inc → Surface Mines**

- 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:** Pounding Mill Coal Co Inc → Surface Mines; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Call & Ramsey → Surface Mines; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Call & Ramsey → Pounding Mill Coal Co Inc; 1950-01-01 to current/open; source msha-controller-operator-history