# Relationship history for MSHA mine 3304383

Current hierarchy: **Martin Marietta Materials Inc → Martin Marietta Materials Inc → New Miami 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:** Martin Marietta Materials Inc → New Miami Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** James P  Jurgensen → New Miami Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Southern Ohio Aggregates → New Miami Plant; 1996-08-01 to 2015-02-22; source msha-controller-operator-history
- **controller_controls_operator:** James P  Jurgensen → Southern Ohio Aggregates; 1996-08-01 to 2015-02-22; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Materials Inc → New Miami Plant; 2015-02-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Materials Inc; 2015-02-23 to current/open; source msha-controller-operator-history