# Relationship history for MSHA mine 3101942

Current hierarchy: **Vulcan Materials Company → Florida Rock Industries Inc → Johnston Sand 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

- **controller_controls_mine:** Florida Rock Industries Inc → Johnston Sand Plant; 1950-01-01 to 2007-11-15; source msha-controller-operator-history
- **operator_operates_mine:** Jo Co S & G Inc → Johnston Sand Plant; 1982-10-01 to 1988-02-29; source msha-controller-operator-history
- **controller_controls_mine:** Cretini A S → Johnston Sand Plant; 1982-10-01 to 1988-02-29; source msha-controller-operator-history
- **controller_controls_operator:** Cretini A S → Jo Co S & G Inc; 1982-10-01 to 1988-02-29; source msha-controller-operator-history
- **operator_operates_mine:** Florida Rock Industries Inc → Johnston Sand Plant; 1988-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Florida Rock Industries Inc → Florida Rock Industries Inc; 1988-03-01 to 2007-11-15; source msha-controller-operator-history
- **controller_controls_mine:** Vulcan Materials Company → Johnston Sand Plant; 2007-11-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Vulcan Materials Company → Florida Rock Industries Inc; 2007-11-16 to current/open; source msha-controller-operator-history