# Relationship history for MSHA mine 4105899

Current hierarchy: **Martin Marietta Materials Inc → Martin Marietta Materials Southwest LLC → Portable Crusher HTX**

- 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 → Portable Crusher HTX; 2007-11-26 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Materials Southwest LLC → Portable Crusher HTX; 2026-07-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Materials Southwest LLC; 2026-07-20 to current/open; source msha-controller-operator-history