# Relationship history for MSHA mine 0200139

Current hierarchy: **BHP Billiton → BHP Copper Inc → BHP Copper - Miami Unit**

- 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:** Cities Service Company → BHP Copper - Miami Unit; 1950-01-01 to 1983-03-09; source msha-controller-operator-history
- **controller_controls_mine:** Cities Service Company → BHP Copper - Miami Unit; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Cities Service Company → Cities Service Company; 1950-01-01 to 1983-03-09; source msha-controller-operator-history
- **operator_operates_mine:** Pinto Valley Copper Corp → BHP Copper - Miami Unit; 1983-03-10 to 1987-03-09; source msha-controller-operator-history
- **controller_controls_mine:** Newmont Corporation → BHP Copper - Miami Unit; 1983-03-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Newmont Corporation → Pinto Valley Copper Corp; 1983-03-10 to 1987-03-09; source msha-controller-operator-history
- **operator_operates_mine:** Magma Copper Company → BHP Copper - Miami Unit; 1987-03-10 to 2013-10-09; source msha-controller-operator-history
- **controller_controls_mine:** Magma Copper Company → BHP Copper - Miami Unit; 1987-03-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Magma Copper Company → Magma Copper Company; 1987-03-10 to 2013-10-09; source msha-controller-operator-history
- **controller_controls_mine:** Broken Hill Proprietary Company Ltd → BHP Copper - Miami Unit; 1996-02-22 to 2012-08-22; source msha-controller-operator-history
- **controller_controls_mine:** BHP Billiton → BHP Copper - Miami Unit; 2012-08-23 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** BHP Copper Inc → BHP Copper - Miami Unit; 2013-10-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** BHP Billiton → BHP Copper Inc; 2013-10-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Broken Hill Proprietary Company Ltd → BHP Copper Inc; 2013-10-10 to 2012-08-22; source msha-controller-operator-history