# Relationship history for MSHA mine 4200402

Current hierarchy: **Parson Jack B Companies → Jack B Parson Company Inc → Parson Hyrum 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:** Parson Jack B Companies → Parson Hyrum Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Savage Ready Mix Company → Parson Hyrum Pit; 1950-01-01 to 1980-02-28; source msha-controller-operator-history
- **controller_controls_mine:** Savage Bert → Parson Hyrum Pit; 1950-01-01 to 1980-02-28; source msha-controller-operator-history
- **controller_controls_operator:** Savage Bert → Savage Ready Mix Company; 1950-01-01 to 1980-02-28; source msha-controller-operator-history
- **operator_operates_mine:** Jack B Parson Company Inc → Parson Hyrum Pit; 1980-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Parson Jack B Companies → Jack B Parson Company Inc; 1980-03-01 to current/open; source msha-controller-operator-history