# Relationship history for MSHA mine 4400018

Current hierarchy: **Brosius B M & A C → Broken Hills Enterprises → Broken Hills Shale 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:** Ryder Corp → Broken Hills Shale Pit; 1950-01-01 to 1980-04-30; source msha-controller-operator-history
- **controller_controls_mine:** Ryder Harvey L → Broken Hills Shale Pit; 1950-01-01 to 1980-04-30; source msha-controller-operator-history
- **controller_controls_operator:** Ryder Harvey L → Ryder Corp; 1950-01-01 to 1980-04-30; source msha-controller-operator-history
- **operator_operates_mine:** Broken Hills Enterprises → Broken Hills Shale Pit; 1980-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Brosius B M & A C → Broken Hills Shale Pit; 1980-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Brosius B M & A C → Broken Hills Enterprises; 1980-05-01 to current/open; source msha-controller-operator-history