# Relationship history for MSHA mine 4202558

Current hierarchy: **CRH PLC → Tru Crushing, Inc. → Portable #4**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** CRH PLC → Portable #4; 2002-05-30 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Steve R  Zabriskie → Portable #4; 2003-06-28 to 2008-04-10; source msha-controller-operator-history
- **controller_controls_mine:** Martin T  White → Portable #4; 2008-04-11 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Tru Crushing Inc → Portable #4; 2010-09-28 to 2010-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Martin T  White → Tru Crushing Inc; 2010-09-28 to 2010-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Steve R  Zabriskie → Tru Crushing Inc; 2010-09-28 to 2008-04-10; source msha-controller-operator-history
- **operator_operates_mine:** Staker Parson Companies → Portable #4; 2011-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Staker Parson Companies; 2011-01-01 to current/open; source msha-controller-operator-history