# Relationship history for MSHA mine 0900219

Current hierarchy: **Pasco E E → Pasco Mining Inc → Graves Mountain Plant**

- 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:** Aluminum Silicates Company → Graves Mountain Plant; 1950-01-01 to 1984-12-17; source msha-controller-operator-history
- **controller_controls_mine:** Asea Brown Boveri Ltd (ABB) → Graves Mountain Plant; 1950-01-01 to 1984-12-17; source msha-controller-operator-history
- **controller_controls_operator:** Asea Brown Boveri Ltd (ABB) → Aluminum Silicates Company; 1950-01-01 to 1984-12-17; source msha-controller-operator-history
- **operator_operates_mine:** Pasco Mining Inc → Graves Mountain Plant; 1984-12-18 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Pasco E E → Graves Mountain Plant; 1984-12-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Pasco E E → Pasco Mining Inc; 1984-12-18 to current/open; source msha-controller-operator-history