# Relationship history for MSHA mine 1513619

Current hierarchy: **Aiken L D → Aiken Mining Company → No 4 Surface 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

- **controller_controls_mine:** Aiken L D → No 4 Surface Mine; 1977-06-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Aiken Mining Company → No 4 Surface Mine; 1982-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Aiken L D → Aiken Mining Company; 1982-07-01 to current/open; source msha-controller-operator-history