# Relationship history for MSHA mine 1201438

Current hierarchy: **CRH PLC → Mulzer Crushed Stone Inc → Tower Quarry**

- 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:** Bart  Mulzer et al → Tower Quarry; 1950-01-01 to 2017-02-09; source msha-controller-operator-history
- **operator_operates_mine:** Bloomington Crushed Stone Company Inc → Tower Quarry; 1950-01-01 to 1983-08-15; source msha-controller-operator-history
- **controller_controls_mine:** Rogers Group Inc → Tower Quarry; 1950-01-01 to 1983-08-15; source msha-controller-operator-history
- **controller_controls_operator:** Rogers Group Inc → Bloomington Crushed Stone Company Inc; 1950-01-01 to 1983-08-15; source msha-controller-operator-history
- **operator_operates_mine:** Mulzer Crushed Stone Inc → Tower Quarry; 1983-08-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bart  Mulzer et al → Mulzer Crushed Stone Inc; 1983-08-16 to 2017-02-09; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → Tower Quarry; 2017-02-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Mulzer Crushed Stone Inc; 2017-02-10 to current/open; source msha-controller-operator-history