# Relationship history for MSHA mine 0900888

Current hierarchy: **Milton O  Blankenship → Blankenship Sand Company → Blankenship Sand Dredge No 2**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Milton O  Blankenship → Blankenship Sand Dredge No 2; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Blankenship Sand Company → Blankenship Sand Dredge No 2; 1978-03-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Milton O  Blankenship → Blankenship Sand Company; 1978-03-09 to current/open; source msha-controller-operator-history