# Relationship history for MSHA mine 1513868

Current hierarchy: **Day Linda → Da-Coal Company → No 1 Surface**

- 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:** Da-Coal Company → No 1 Surface; 1982-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Day Linda → No 1 Surface; 1982-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Day Linda → Da-Coal Company; 1982-12-01 to current/open; source msha-controller-operator-history