# Relationship history for MSHA mine 0301804

Current hierarchy: **Martin Marietta Materials Inc → Hanson Aggregates → PRESCOTT 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

- **controller_controls_mine:** Hanson PLC → PRESCOTT PLANT; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Hanson PLC → PRESCOTT PLANT; 1988-11-14 to 2007-08-22; source msha-controller-operator-history
- **operator_operates_mine:** Hanson Aggregates West Inc → PRESCOTT PLANT; 1999-02-01 to 2004-05-09; source msha-controller-operator-history
- **controller_controls_operator:** Hanson PLC → Hanson Aggregates West Inc; 1999-02-01 to 2004-05-09; source msha-controller-operator-history
- **operator_operates_mine:** Hanson Aggregates → PRESCOTT PLANT; 2004-05-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hanson PLC → Hanson Aggregates; 2004-05-10 to 2007-08-22; source msha-controller-operator-history
- **controller_controls_mine:** Heidelberg Materials AG → PRESCOTT PLANT; 2007-08-23 to 2021-09-30; source msha-controller-operator-history
- **controller_controls_operator:** Heidelberg Materials AG → Hanson Aggregates; 2007-08-23 to 2021-09-30; source msha-controller-operator-history
- **controller_controls_mine:** Martin Marietta Materials Inc → PRESCOTT PLANT; 2021-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Hanson Aggregates; 2021-10-01 to current/open; source msha-controller-operator-history