# Relationship history for MSHA mine 3302784

Current hierarchy: **CRH PLC → Columbus Limestone Inc → Columbus Limestone Quarry**

- 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:** American Aggregates Corp → Columbus Limestone Quarry; 1950-01-01 to 1987-02-28; source msha-controller-operator-history
- **controller_controls_mine:** American Aggregates Corp → Columbus Limestone Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** American Aggregates Corp → American Aggregates Corp; 1950-01-01 to 1987-02-28; source msha-controller-operator-history
- **controller_controls_mine:** Martin Marietta Materials Inc → Columbus Limestone Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Consolidated Gold Fields Limited → Columbus Limestone Quarry; 1987-02-04 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** American Aggregates Corp → Columbus Limestone Quarry; 1987-03-01 to 1989-08-09; source msha-controller-operator-history
- **controller_controls_operator:** Consolidated Gold Fields Limited → American Aggregates Corp; 1987-03-01 to 1989-08-09; source msha-controller-operator-history
- **controller_controls_mine:** Hanson PLC → Columbus Limestone Quarry; 1989-03-10 to 1990-02-01; source msha-controller-operator-history
- **operator_operates_mine:** American Aggregates Corp → Columbus Limestone Quarry; 1989-08-10 to 1990-02-01; source msha-controller-operator-history
- **controller_controls_operator:** Hanson PLC → American Aggregates Corp; 1989-08-10 to 1990-02-01; source msha-controller-operator-history
- **operator_operates_mine:** American Aggregates Corp → Columbus Limestone Quarry; 1990-02-02 to 1997-05-27; source msha-controller-operator-history
- **controller_controls_mine:** CSR Ltd → Columbus Limestone Quarry; 1990-02-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CSR Ltd → American Aggregates Corp; 1990-02-02 to 1997-05-27; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Aggregates → Columbus Limestone Quarry; 1997-05-28 to 2002-05-31; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Aggregates; 1997-05-28 to 2002-05-31; source msha-controller-operator-history
- **operator_operates_mine:** Columbus Limestone Inc → Columbus Limestone Quarry; 2002-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → Columbus Limestone Quarry; 2002-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Columbus Limestone Inc; 2002-06-01 to current/open; source msha-controller-operator-history