# Relationship history for MSHA mine 0102180

Current hierarchy: **Bass Robert Wayne → Blackwater Coal Company → Andrew**

- 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:** Blackwater Coal Company → Andrew; 1980-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Bass Robert Wayne → Andrew; 1980-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bass Robert Wayne → Blackwater Coal Company; 1980-03-01 to current/open; source msha-controller-operator-history