# Relationship history for MSHA mine 0202251

Current hierarchy: **BHP Billiton → BHP Copper → BHP 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

- **controller_controls_mine:** Newmont Corporation → BHP Open Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Magma Copper Company → BHP Open Pit; 1985-05-01 to 1987-03-29; source msha-controller-operator-history
- **controller_controls_operator:** Newmont Corporation → Magma Copper Company; 1985-05-01 to 1987-03-29; source msha-controller-operator-history
- **controller_controls_mine:** Magma Copper Company → BHP Open Pit; 1987-03-10 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Magma Copper Company → BHP Open Pit; 1987-03-30 to 1996-02-21; source msha-controller-operator-history
- **controller_controls_operator:** Magma Copper Company → Magma Copper Company; 1987-03-30 to 1996-02-21; source msha-controller-operator-history
- **operator_operates_mine:** BHP Copper → BHP Open Pit; 1996-02-22 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Broken Hill Proprietary Company Ltd → BHP Open Pit; 1996-02-22 to 2012-08-22; source msha-controller-operator-history
- **controller_controls_operator:** Broken Hill Proprietary Company Ltd → BHP Copper; 1996-02-22 to 2012-08-22; source msha-controller-operator-history
- **controller_controls_mine:** BHP Billiton → BHP Open Pit; 2012-08-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** BHP Billiton → BHP Copper; 2012-08-23 to current/open; source msha-controller-operator-history