# Relationship history for MSHA mine 2800546

Current hierarchy: **WHIBCO, Inc. → Whibco of New Jersey, Inc. → PORT ELIZABETH 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Whibco Inc → PORT ELIZABETH PLANT; 1950-01-01 to 2003-12-31; source msha-controller-operator-history
- **controller_controls_mine:** WHIBCO, Inc. → PORT ELIZABETH PLANT; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** WHIBCO, Inc. → Whibco Inc; 1950-01-01 to 2003-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Whibco of New Jersey, Inc. → PORT ELIZABETH PLANT; 2004-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** WHIBCO, Inc. → PORT ELIZABETH PLANT; 2004-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** WHIBCO, Inc. → Whibco of New Jersey, Inc.; 2004-01-01 to current/open; source msha-controller-operator-history