# Relationship history for MSHA mine 1200693

Current hierarchy: **Martin Marietta Materials Inc → Martin Marietta Aggregates → Kokomo Sand**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Martin Marietta Materials Inc → Kokomo Sand; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Kyle Pickering Gravel Company Inc → Kokomo Sand; 1950-01-01 to 1982-08-23; source msha-controller-operator-history
- **controller_controls_mine:** Lee Richard H → Kokomo Sand; 1950-01-01 to 1982-08-23; source msha-controller-operator-history
- **controller_controls_operator:** Lee Richard H → Kyle Pickering Gravel Company Inc; 1950-01-01 to 1982-08-23; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Aggregates → Kokomo Sand; 1982-08-24 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Aggregates; 1982-08-24 to current/open; source msha-controller-operator-history