# Relationship history for MSHA mine 0900912

Current hierarchy: **Cemex S A → CEMEX Construction Materials Florida, LLC → UNION SAND MINE**

- 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:** Union Silica Mining → UNION SAND MINE; 1979-09-01 to 1983-03-01; source msha-controller-operator-history
- **controller_controls_mine:** Herman  Morris → UNION SAND MINE; 1979-09-01 to 1998-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Herman  Morris → Union Silica Mining; 1979-09-01 to 1983-03-01; source msha-controller-operator-history
- **controller_controls_mine:** CSR Ltd → UNION SAND MINE; 1982-10-27 to 2003-03-31; source msha-controller-operator-history
- **controller_controls_mine:** B E  Bledsoe → UNION SAND MINE; 1982-12-28 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Satilla Sand Company Inc → UNION SAND MINE; 1983-03-02 to 1987-09-02; source msha-controller-operator-history
- **controller_controls_operator:** B E  Bledsoe → Satilla Sand Company Inc; 1983-03-02 to 1987-09-02; source msha-controller-operator-history
- **operator_operates_mine:** Union Silica Mining → UNION SAND MINE; 1987-09-03 to 1998-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Herman  Morris → Union Silica Mining; 1987-09-03 to 1998-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Rinker Materials of Florida Inc → UNION SAND MINE; 1999-01-01 to 2008-12-18; source msha-controller-operator-history
- **controller_controls_operator:** CSR Ltd → Rinker Materials of Florida Inc; 1999-01-01 to 2003-03-31; source msha-controller-operator-history
- **controller_controls_mine:** Rinker Group Ltd → UNION SAND MINE; 2003-04-01 to 2007-07-09; source msha-controller-operator-history
- **controller_controls_operator:** Rinker Group Ltd → Rinker Materials of Florida Inc; 2003-04-01 to 2007-07-09; source msha-controller-operator-history
- **controller_controls_mine:** Cemex S A → UNION SAND MINE; 2007-07-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Cemex S A → Rinker Materials of Florida Inc; 2007-07-10 to 2008-12-18; source msha-controller-operator-history
- **controller_controls_mine:** Cemex S A → UNION SAND MINE; 2008-12-04 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** CEMEX Construction Materials Florida, LLC → UNION SAND MINE; 2008-12-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Cemex S A → CEMEX Construction Materials Florida, LLC; 2008-12-19 to current/open; source msha-controller-operator-history