# Relationship history for MSHA mine 3304741

Current hierarchy: **CRH PLC → Stoneco, Inc. → Portable Plant**

- 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:** Johnson S E Companies Inc → Portable Plant; 1950-01-01 to 2003-06-15; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → Portable Plant; 2003-06-16 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Stoneco, Inc. → Portable Plant; 2018-08-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Johnson S E Companies Inc → Stoneco, Inc.; 2018-08-02 to 2003-06-15; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Stoneco, Inc.; 2018-08-02 to current/open; source msha-controller-operator-history