# Relationship history for MSHA mine 4603800

Current hierarchy: **Martin Marietta Materials Inc → Martin Marietta Aggregates → DREDGE LUCAS**

- 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 → DREDGE LUCAS; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Dravo Corp → DREDGE LUCAS; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Ohio River Sand & Gravel → DREDGE LUCAS; 1950-01-01 to 1981-03-22; source msha-controller-operator-history
- **controller_controls_mine:** Mc Donough Company → DREDGE LUCAS; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mc Donough Company → Ohio River Sand & Gravel; 1950-01-01 to 1981-03-22; source msha-controller-operator-history
- **operator_operates_mine:** Dravo Basic Materials Company Inc → DREDGE LUCAS; 1981-03-23 to 1995-01-02; source msha-controller-operator-history
- **controller_controls_operator:** Dravo Corp → Dravo Basic Materials Company Inc; 1981-03-23 to 1995-01-02; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Aggregates → DREDGE LUCAS; 1995-01-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Aggregates; 1995-01-03 to current/open; source msha-controller-operator-history