# Relationship history for MSHA mine 1508237

Current hierarchy: **Barnett Robert H → Barnett Enterprise Inc → No 2 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

- **operator_operates_mine:** Barnett Enterprise Inc → No 2 Surface Mine; 1975-04-14 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Barnett Robert H → No 2 Surface Mine; 1975-04-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Barnett Robert H → Barnett Enterprise Inc; 1975-04-14 to current/open; source msha-controller-operator-history