# Relationship history for MSHA mine 3001983

Current hierarchy: **Horsehead Industries Inc → Zca Mines Inc → No 2 Open Pit**

- 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:** St Joe Resources Company → No 2 Open Pit; 1950-01-01 to 1991-06-30; source msha-controller-operator-history
- **controller_controls_mine:** Fluor Corp → No 2 Open Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Fluor Corp → St Joe Resources Company; 1950-01-01 to 1991-06-30; source msha-controller-operator-history
- **controller_controls_mine:** Horsehead Industries Inc → No 2 Open Pit; 1987-09-17 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Zca Mines Inc → No 2 Open Pit; 1991-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Horsehead Industries Inc → Zca Mines Inc; 1991-07-01 to current/open; source msha-controller-operator-history