# Relationship history for MSHA mine 0900473

Current hierarchy: **BASF SE → Engelhard Corp → Gardner 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:** Engelhard Corp → Gardner Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Engelhard Corp → Gardner Plant; 1950-01-01 to 2006-07-31; source msha-controller-operator-history
- **controller_controls_operator:** Engelhard Corp → Engelhard Corp; 1950-01-01 to 2006-07-31; source msha-controller-operator-history
- **controller_controls_mine:** BASF SE → Gardner Plant; 2006-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** BASF SE → Engelhard Corp; 2006-08-01 to current/open; source msha-controller-operator-history