# Relationship history for MSHA mine 4503768

Current hierarchy: **Amrize Ltd → Amrize West Central Inc. → Amrize Siper Pit**

- 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:** Steven B  Cowden → Amrize Siper Pit; 1950-01-01 to 2017-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Aggregate Industries PLC → Amrize Siper Pit; 1997-05-14 to 2009-04-29; source msha-controller-operator-history
- **controller_controls_mine:** Holcim Ltd → Amrize Siper Pit; 2009-04-30 to 2015-07-09; source msha-controller-operator-history
- **controller_controls_mine:** Holcim Ltd → Amrize Siper Pit; 2015-07-10 to 2025-06-22; source msha-controller-operator-history
- **operator_operates_mine:** Cowden Inc → Amrize Siper Pit; 2017-03-22 to 2021-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Steven B  Cowden → Cowden Inc; 2017-03-22 to 2017-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Brent  Cowden et al → Amrize Siper Pit; 2018-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Brent  Cowden et al → Cowden Inc; 2018-01-01 to 2021-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Deryk  Cowden et al → Cowden Inc; 2018-01-01 to 2021-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Amrize ACM PNW Inc. → Amrize Siper Pit; 2022-01-01 to 2026-01-01; source msha-controller-operator-history
- **controller_controls_mine:** Holcim Ltd → Amrize Siper Pit; 2022-01-01 to 2025-06-22; source msha-controller-operator-history
- **controller_controls_operator:** Holcim Ltd → Amrize ACM PNW Inc.; 2022-01-01 to 2025-06-22; source msha-controller-operator-history
- **controller_controls_mine:** Amrize Ltd → Amrize Siper Pit; 2025-06-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Amrize Ltd → Amrize ACM PNW Inc.; 2025-06-23 to 2026-01-01; source msha-controller-operator-history
- **operator_operates_mine:** Amrize West Central Inc. → Amrize Siper Pit; 2026-01-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Holcim Ltd → Amrize West Central Inc.; 2026-01-02 to 2025-06-22; source msha-controller-operator-history
- **controller_controls_operator:** Amrize Ltd → Amrize West Central Inc.; 2026-01-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Holcim Ltd → Amrize West Central Inc.; 2026-01-02 to 2015-07-09; source msha-controller-operator-history
- **controller_controls_operator:** Aggregate Industries PLC → Amrize West Central Inc.; 2026-01-02 to 2009-04-29; source msha-controller-operator-history