# Relationship history for MSHA mine 4102886

Current hierarchy: **Martin Marietta Materials Inc → Martin Marietta Materials Southwest, LLC → GARWOOD 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Martin Marietta Materials Inc → GARWOOD PLANT; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** B & B Gravel Company → GARWOOD PLANT; 1979-01-01 to 2000-08-31; source msha-controller-operator-history
- **controller_controls_mine:** Mark  Barten → GARWOOD PLANT; 1979-01-01 to 2000-08-31; source msha-controller-operator-history
- **controller_controls_operator:** Mark  Barten → B & B Gravel Company; 1979-01-01 to 2000-08-31; source msha-controller-operator-history
- **controller_controls_mine:** Martin Marietta Materials Inc → GARWOOD PLANT; 1998-12-17 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Materials Southwest Ltd → GARWOOD PLANT; 2000-09-01 to 2007-05-16; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Materials Southwest Ltd; 2000-09-01 to 2007-05-16; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Materials, Inc. → GARWOOD PLANT; 2007-05-17 to 2023-12-13; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Materials, Inc.; 2007-05-17 to 2023-12-13; source msha-controller-operator-history
- **controller_controls_mine:** Martin Marietta Materials Inc → GARWOOD PLANT; 2007-11-26 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Materials Southwest, LLC → GARWOOD PLANT; 2023-12-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Materials Southwest, LLC; 2023-12-14 to current/open; source msha-controller-operator-history