# Relationship history for MSHA mine 0500037

Current hierarchy: **Amrize Ltd → Amrize Cement Inc. → Amrize Portland 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: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **operator_operates_mine:** Ideal Basic Industries Inc → Amrize Portland Plant; 1950-01-01 to 1989-06-14; source msha-controller-operator-history
- **controller_controls_mine:** Ideal Basic Industries Inc → Amrize Portland Plant; 1950-01-01 to 1989-06-14; source msha-controller-operator-history
- **controller_controls_operator:** Ideal Basic Industries Inc → Ideal Basic Industries Inc; 1950-01-01 to 1989-06-14; source msha-controller-operator-history
- **controller_controls_mine:** Holcim Ltd → Amrize Portland Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Holnam Inc → Amrize Portland Plant; 1989-06-15 to 2001-12-18; source msha-controller-operator-history
- **controller_controls_operator:** Holcim Ltd → Holnam Inc; 1989-06-15 to 2001-12-18; source msha-controller-operator-history
- **controller_controls_mine:** Holcim Ltd → Amrize Portland Plant; 2001-12-12 to 2015-07-09; source msha-controller-operator-history
- **operator_operates_mine:** Amrize Cement Inc. → Amrize Portland Plant; 2001-12-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Holcim Ltd → Amrize Cement Inc.; 2001-12-19 to 2015-07-09; source msha-controller-operator-history
- **controller_controls_mine:** Holcim Ltd → Amrize Portland Plant; 2015-07-10 to 2025-06-22; source msha-controller-operator-history
- **controller_controls_operator:** Holcim Ltd → Amrize Cement Inc.; 2015-07-10 to 2025-06-22; source msha-controller-operator-history
- **controller_controls_mine:** Amrize Ltd → Amrize Portland Plant; 2025-06-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Amrize Ltd → Amrize Cement Inc.; 2025-06-23 to current/open; source msha-controller-operator-history