# Relationship history for MSHA mine 1508028

Current hierarchy: **Burwick Clarence → Trela Coals Inc → No 2 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

- **operator_operates_mine:** Trela Coals Inc → No 2 Mine; 1977-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Burwick Clarence → No 2 Mine; 1977-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Burwick Clarence → Trela Coals Inc; 1977-04-01 to current/open; source msha-controller-operator-history