# Relationship history for MSHA mine 0401937

Current hierarchy: **Vulcan Materials Company → CalMat Co → Sanger 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Sanger Rock & Sand → Sanger Plant; 1950-01-01 to 1990-07-31; source msha-controller-operator-history
- **controller_controls_mine:** J F  Baun → Sanger Plant; 1950-01-01 to 1990-07-31; source msha-controller-operator-history
- **controller_controls_operator:** J F  Baun → Sanger Rock & Sand; 1950-01-01 to 1990-07-31; source msha-controller-operator-history
- **controller_controls_mine:** Calmat Company → Sanger Plant; 1985-08-01 to 1999-01-05; source msha-controller-operator-history
- **operator_operates_mine:** Calmat Of Central California → Sanger Plant; 1990-08-01 to 1999-01-05; source msha-controller-operator-history
- **controller_controls_operator:** Calmat Company → Calmat Of Central California; 1990-08-01 to 1999-01-05; source msha-controller-operator-history
- **operator_operates_mine:** CalMat Co → Sanger Plant; 1999-01-06 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Legacy Vulcan Corp (Form:Vulcan Materials Co) → Sanger 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 → Sanger 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