# Relationship history for MSHA mine 1504638

Current hierarchy: **Brown Lloyd → Big Three Coal Company → No 1-A**

- 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:** Big Three Coal Company → No 1-A; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Brown Lloyd → No 1-A; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Brown Lloyd → Big Three Coal Company; 1950-01-01 to current/open; source msha-controller-operator-history