# Relationship history for MSHA mine 1800304

Current hierarchy: **Amrize Ltd → Amrize Mid-Atlantic Inc. → Amrize Kirby Road Sand & Gravel**

- 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:** Bardon Inc → Amrize Kirby Road Sand & Gravel; 1950-01-01 to 2002-06-16; source msha-controller-operator-history
- **controller_controls_mine:** Aggregate Industries PLC → Amrize Kirby Road Sand & Gravel; 1950-01-01 to 2009-04-29; source msha-controller-operator-history
- **controller_controls_operator:** Aggregate Industries PLC → Bardon Inc; 1950-01-01 to 2002-06-16; source msha-controller-operator-history
- **operator_operates_mine:** Silver Hill Materials, LLC → Amrize Kirby Road Sand & Gravel; 2002-06-17 to 2011-06-30; source msha-controller-operator-history
- **controller_controls_mine:** Aggregate Industries PLC → Amrize Kirby Road Sand & Gravel; 2002-06-17 to 2009-04-29; source msha-controller-operator-history
- **controller_controls_operator:** Aggregate Industries PLC → Silver Hill Materials, LLC; 2002-06-17 to 2009-04-29; source msha-controller-operator-history
- **controller_controls_mine:** Holcim Ltd → Amrize Kirby Road Sand & Gravel; 2009-04-30 to 2015-07-09; source msha-controller-operator-history
- **controller_controls_operator:** Holcim Ltd → Bardon Inc; 2009-04-30 to 2002-06-16; source msha-controller-operator-history
- **controller_controls_mine:** Holcim Ltd → Amrize Kirby Road Sand & Gravel; 2009-04-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Holcim Ltd → Silver Hill Materials, LLC; 2009-04-30 to 2011-06-30; source msha-controller-operator-history
- **operator_operates_mine:** Amrize Mid-Atlantic Inc. → Amrize Kirby Road Sand & Gravel; 2011-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Holcim Ltd → Amrize Mid-Atlantic Inc.; 2011-07-01 to 2015-07-09; source msha-controller-operator-history
- **controller_controls_operator:** Aggregate Industries PLC → Amrize Mid-Atlantic Inc.; 2011-07-01 to 2009-04-29; source msha-controller-operator-history
- **controller_controls_mine:** Holcim Ltd → Amrize Kirby Road Sand & Gravel; 2015-07-10 to 2025-06-22; source msha-controller-operator-history
- **controller_controls_operator:** Holcim Ltd → Bardon Inc; 2015-07-10 to 2002-06-16; source msha-controller-operator-history
- **controller_controls_operator:** Holcim Ltd → Amrize Mid-Atlantic Inc.; 2015-07-10 to 2025-06-22; source msha-controller-operator-history
- **controller_controls_mine:** Amrize Ltd → Amrize Kirby Road Sand & Gravel; 2025-06-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Amrize Ltd → Bardon Inc; 2025-06-23 to 2002-06-16; source msha-controller-operator-history
- **controller_controls_operator:** Amrize Ltd → Amrize Mid-Atlantic Inc.; 2025-06-23 to current/open; source msha-controller-operator-history