# Relationship history for MSHA mine 1202043

Current hierarchy: **Blackford Raymond → Blackford Gravel Company → Blackford Gravel Company**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **operator_operates_mine:** Blackford Gravel Company → Blackford Gravel Company; 1988-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Blackford Raymond → Blackford Gravel Company; 1988-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Blackford Raymond → Blackford Gravel Company; 1988-10-01 to current/open; source msha-controller-operator-history