# Relationship history for MSHA mine 3304394

Current hierarchy: **Martin Marietta Materials Inc → Martin Marietta Materials → Portable Plant #3-183 (Ohio Recycling)**

- 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

- **controller_controls_mine:** Martin Marietta Materials Inc → Portable Plant #3-183 (Ohio Recycling); 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Aggregates → Portable Plant #3-183 (Ohio Recycling); 1997-05-01 to 2009-01-04; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Aggregates; 1997-05-01 to 2009-01-04; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Materials → Portable Plant #3-183 (Ohio Recycling); 2009-01-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Materials; 2009-01-05 to current/open; source msha-controller-operator-history