# Relationship history for MSHA mine 0401829

Current hierarchy: **Vulcan Materials Company → CalMat Co → Wheeler Ridge 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:** Kern Rock Company → Wheeler Ridge Plant; 1950-01-01 to 1985-12-19; source msha-controller-operator-history
- **controller_controls_mine:** Gertrude  Sill → Wheeler Ridge Plant; 1950-01-01 to 1985-12-19; source msha-controller-operator-history
- **controller_controls_operator:** Gertrude  Sill → Kern Rock Company; 1950-01-01 to 1985-12-19; source msha-controller-operator-history
- **controller_controls_mine:** Calmat Company → Wheeler Ridge Plant; 1985-08-01 to 1999-01-05; source msha-controller-operator-history
- **controller_controls_mine:** Koppers Company Inc → Wheeler Ridge Plant; 1985-12-19 to 1988-11-13; source msha-controller-operator-history
- **operator_operates_mine:** Kern Rock Company → Wheeler Ridge Plant; 1985-12-20 to 1988-11-13; source msha-controller-operator-history
- **controller_controls_operator:** Koppers Company Inc → Kern Rock Company; 1985-12-20 to 1988-11-13; source msha-controller-operator-history
- **operator_operates_mine:** Kern Rock Company → Wheeler Ridge Plant; 1988-11-14 to 1997-10-12; source msha-controller-operator-history
- **controller_controls_mine:** Hanson PLC → Wheeler Ridge Plant; 1988-11-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hanson PLC → Kern Rock Company; 1988-11-14 to 1997-10-12; source msha-controller-operator-history
- **operator_operates_mine:** Calmat Of Central California → Wheeler Ridge Plant; 1997-10-13 to 1999-01-05; source msha-controller-operator-history
- **controller_controls_operator:** Calmat Company → Calmat Of Central California; 1997-10-13 to 1999-01-05; source msha-controller-operator-history
- **operator_operates_mine:** CalMat Co → Wheeler Ridge Plant; 1999-01-06 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Legacy Vulcan Corp (Form:Vulcan Materials Co) → Wheeler Ridge Plant; 1999-01-06 to 2007-11-15; source msha-controller-operator-history
- **controller_controls_operator:** Legacy Vulcan Corp (Form:Vulcan Materials Co) → CalMat Co; 1999-01-06 to 2007-11-15; source msha-controller-operator-history
- **controller_controls_mine:** Vulcan Materials Company → Wheeler Ridge Plant; 2007-11-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Vulcan Materials Company → CalMat Co; 2007-11-16 to current/open; source msha-controller-operator-history