# Relationship history for MSHA mine 4105170

Current hierarchy: **Martin Marietta Materials Inc → Martin Marietta Materials Southwest, LLC → Medina Rock & Rail**

- 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 → Medina Rock & Rail; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Martin Marietta Materials Inc → Medina Rock & Rail; 2007-11-26 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Materials Inc. → Medina Rock & Rail; 2016-01-19 to 2021-10-21; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Materials Inc.; 2016-01-19 to 2021-10-21; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Materials Southwest, LLC → Medina Rock & Rail; 2021-10-22 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Materials Southwest, LLC; 2021-10-22 to current/open; source msha-controller-operator-history