# Relationship history for MSHA mine 4201717

Current hierarchy: **CRH PLC → Jack B Parson Companies → PORTABLE #5**

- 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 → PORTABLE #5; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Jack B Parson Company Inc → PORTABLE #5; 1981-01-01 to 1999-06-22; source msha-controller-operator-history
- **controller_controls_operator:** Parson Jack B Companies → Jack B Parson Company Inc; 1981-01-01 to 1999-06-22; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → PORTABLE #5; 1996-05-03 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Jack B Parson Companies → PORTABLE #5; 1999-06-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Jack B Parson Companies; 1999-06-23 to current/open; source msha-controller-operator-history