# Relationship history for MSHA mine 4001751

Current hierarchy: **Terra Industries Inc → Tennessee Zinc Div/Inspiration Development Co → Beaver Creek Mine**

- 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:** New Jersey Zinc Company → Beaver Creek Mine; 1950-01-01 to 1983-07-13; source msha-controller-operator-history
- **controller_controls_mine:** Gulf + Western Industries Inc → Beaver Creek Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Gulf + Western Industries Inc → New Jersey Zinc Company; 1950-01-01 to 1983-07-13; source msha-controller-operator-history
- **operator_operates_mine:** Tennessee Zinc Div/Inspiration Development Co → Beaver Creek Mine; 1983-07-14 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Terra Industries Inc → Beaver Creek Mine; 1983-07-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Terra Industries Inc → Tennessee Zinc Div/Inspiration Development Co; 1983-07-14 to current/open; source msha-controller-operator-history