# Relationship history for MSHA mine 0500073

Current hierarchy: **Amrize Ltd → Amrize West Central Inc. → Amrize Canon City 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

- **operator_operates_mine:** Sturbaum Construction Company → Amrize Canon City Quarry; 1950-01-01 to 1983-02-14; source msha-controller-operator-history
- **controller_controls_mine:** Stanley R  Sturbaum → Amrize Canon City Quarry; 1950-01-01 to 1983-02-14; source msha-controller-operator-history
- **controller_controls_operator:** Stanley R  Sturbaum → Sturbaum Construction Company; 1950-01-01 to 1983-02-14; source msha-controller-operator-history
- **operator_operates_mine:** Sniders' Aggregate Inc → Amrize Canon City Quarry; 1983-02-15 to 1993-04-16; source msha-controller-operator-history
- **controller_controls_mine:** Ernest L  Snider → Amrize Canon City Quarry; 1983-02-15 to 1993-04-16; source msha-controller-operator-history
- **controller_controls_operator:** Ernest L  Snider → Sniders' Aggregate Inc; 1983-02-15 to 1993-04-16; source msha-controller-operator-history
- **operator_operates_mine:** Tezak Heavy Equipment, LLC → Amrize Canon City Quarry; 1993-04-17 to 2023-08-08; source msha-controller-operator-history
- **controller_controls_mine:** Daniel E  Tezak → Amrize Canon City Quarry; 1993-04-17 to 2023-03-30; source msha-controller-operator-history
- **controller_controls_operator:** Daniel E  Tezak → Tezak Heavy Equipment, LLC; 1993-04-17 to 2023-03-30; source msha-controller-operator-history
- **controller_controls_mine:** Aggregate Industries PLC → Amrize Canon City Quarry; 1997-05-14 to 2009-04-29; source msha-controller-operator-history
- **controller_controls_mine:** Holcim Ltd → Amrize Canon City Quarry; 2009-04-30 to 2015-07-09; source msha-controller-operator-history
- **controller_controls_mine:** Holcim Ltd → Amrize Canon City Quarry; 2015-07-10 to 2025-06-22; source msha-controller-operator-history
- **controller_controls_mine:** Holcim Ltd → Amrize Canon City Quarry; 2023-03-31 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Holcim Ltd → Tezak Heavy Equipment, LLC; 2023-03-31 to 2023-08-08; source msha-controller-operator-history
- **operator_operates_mine:** Amrize West Central Inc. → Amrize Canon City Quarry; 2023-08-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Holcim Ltd → Amrize West Central Inc.; 2023-08-09 to 2025-06-22; source msha-controller-operator-history
- **controller_controls_operator:** Holcim Ltd → Amrize West Central Inc.; 2023-08-09 to 2015-07-09; source msha-controller-operator-history
- **controller_controls_operator:** Aggregate Industries PLC → Amrize West Central Inc.; 2023-08-09 to 2009-04-29; source msha-controller-operator-history
- **controller_controls_mine:** Amrize Ltd → Amrize Canon City Quarry; 2025-06-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Amrize Ltd → Amrize West Central Inc.; 2025-06-23 to current/open; source msha-controller-operator-history