# Relationship history for MSHA mine 2300141

Current hierarchy: **Martin Marietta Materials Inc → Martin Marietta Materials, Inc. → GREENWOOD QUARRY**

- 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 → GREENWOOD QUARRY; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Mc Kee Quarries Company Inc → GREENWOOD QUARRY; 1950-01-01 to 1990-04-30; source msha-controller-operator-history
- **controller_controls_mine:** J M  Millett → GREENWOOD QUARRY; 1950-01-01 to 1990-04-30; source msha-controller-operator-history
- **controller_controls_operator:** J M  Millett → Mc Kee Quarries Company Inc; 1950-01-01 to 1990-04-30; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Aggregates → GREENWOOD QUARRY; 1990-05-01 to 2005-01-31; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Aggregates; 1990-05-01 to 2005-01-31; source msha-controller-operator-history
- **operator_operates_mine:** Hunt Martin Materials LLC → GREENWOOD QUARRY; 2005-02-01 to 2008-01-14; source msha-controller-operator-history
- **controller_controls_mine:** Martin Marietta Materials Inc et al → GREENWOOD QUARRY; 2005-02-01 to 2014-04-02; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc et al → Hunt Martin Materials LLC; 2005-02-01 to 2008-01-14; source msha-controller-operator-history
- **controller_controls_operator:** Hunt Midwest Enterprises et al → Hunt Martin Materials LLC; 2005-02-01 to 2008-01-14; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Materials, Inc. → GREENWOOD QUARRY; 2008-01-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Materials, Inc.; 2008-01-15 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Martin Marietta Materials Inc → GREENWOOD QUARRY; 2014-04-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Hunt Martin Materials LLC; 2014-04-03 to 2008-01-14; source msha-controller-operator-history