# Relationship history for MSHA mine 2000044

Current hierarchy: **Amrize Ltd → Amrize Cement Inc. → Amrize Alpena 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** National Gypsum Company → Amrize Alpena Plant; 1950-01-01 to 1986-12-29; source msha-controller-operator-history
- **controller_controls_mine:** Lafarge S A → Amrize Alpena Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Lafarge S A → National Gypsum Company; 1950-01-01 to 1986-12-29; source msha-controller-operator-history
- **operator_operates_mine:** Lafarge Corp → Amrize Alpena Plant; 1986-12-30 to 2003-07-31; source msha-controller-operator-history
- **controller_controls_operator:** Lafarge S A → Lafarge Corp; 1986-12-30 to 2003-07-31; source msha-controller-operator-history
- **controller_controls_mine:** Lafarge S A → Amrize Alpena Plant; 2001-07-12 to 2015-07-09; source msha-controller-operator-history
- **controller_controls_mine:** Holcim Ltd → Amrize Alpena Plant; 2001-12-12 to 2015-07-09; source msha-controller-operator-history
- **operator_operates_mine:** Lafarge North America → Amrize Alpena Plant; 2003-08-01 to 2018-09-24; source msha-controller-operator-history
- **controller_controls_operator:** Lafarge S A → Lafarge North America; 2003-08-01 to 2015-07-09; source msha-controller-operator-history
- **controller_controls_mine:** Holcim Ltd → Amrize Alpena Plant; 2015-07-10 to 2025-06-22; source msha-controller-operator-history
- **controller_controls_mine:** Holcim Ltd → Amrize Alpena Plant; 2015-07-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Holcim Ltd → Lafarge North America; 2015-07-10 to 2018-09-24; source msha-controller-operator-history
- **operator_operates_mine:** Amrize Cement Inc. → Amrize Alpena Plant; 2018-09-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Holcim Ltd → Amrize Cement Inc.; 2018-09-25 to 2025-06-22; source msha-controller-operator-history
- **controller_controls_operator:** Holcim Ltd → Amrize Cement Inc.; 2018-09-25 to 2015-07-09; source msha-controller-operator-history
- **controller_controls_mine:** Amrize Ltd → Amrize Alpena 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