# Relationship history for MSHA mine 4600026

Current hierarchy: **Italcementi Spa → Riverton Corporation → Riverton Corporation, Blair 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: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **operator_operates_mine:** Riverton Corp → Riverton Corporation, Blair Plant; 1950-01-01 to 1980-10-31; source msha-controller-operator-history
- **controller_controls_mine:** Investment Corp Of Florida → Riverton Corporation, Blair Plant; 1950-01-01 to 1983-11-27; source msha-controller-operator-history
- **controller_controls_operator:** Investment Corp Of Florida → Riverton Corp; 1950-01-01 to 1980-10-31; source msha-controller-operator-history
- **operator_operates_mine:** Riverton Corporation → Riverton Corporation, Blair Plant; 1980-11-01 to 2003-09-02; source msha-controller-operator-history
- **controller_controls_mine:** Capitol Materials Corporation → Riverton Corporation, Blair Plant; 1980-11-01 to 2002-05-20; source msha-controller-operator-history
- **controller_controls_operator:** Capitol Materials Corporation → Riverton Corporation; 1980-11-01 to 2002-05-20; source msha-controller-operator-history
- **controller_controls_mine:** Italcementi Spa → Riverton Corporation, Blair Plant; 2002-05-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Italcementi Spa → Riverton Corporation; 2002-05-21 to 2003-09-02; source msha-controller-operator-history
- **controller_controls_mine:** Italcementi Spa → Riverton Corporation, Blair Plant; 2003-08-21 to 2016-10-11; source msha-controller-operator-history
- **operator_operates_mine:** Riverton Investment Corp. → Riverton Corporation, Blair Plant; 2003-09-03 to 2003-11-30; source msha-controller-operator-history
- **controller_controls_operator:** Italcementi Spa → Riverton Investment Corp.; 2003-09-03 to 2003-11-30; source msha-controller-operator-history
- **operator_operates_mine:** Riverton Corporation → Riverton Corporation, Blair Plant; 2003-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Italcementi Spa → Riverton Corporation; 2003-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Capitol Materials Corporation → Riverton Corporation; 2003-12-01 to 2002-05-20; source msha-controller-operator-history
- **controller_controls_mine:** Heidelberg Materials AG → Riverton Corporation, Blair Plant; 2016-10-12 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Heidelberg Materials AG → Riverton Investment Corp.; 2016-10-12 to 2003-11-30; source msha-controller-operator-history