# Relationship history for MSHA mine 1302139

Current hierarchy: **Martin Marietta Materials Inc → Martin Marietta Corp → Portable Rock Plant #1**

- 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 → Portable Rock Plant #1; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Larry E  Moore → Portable Rock Plant #1; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Midwest Limestone Company Inc → Portable Rock Plant #1; 1986-03-01 to 1992-05-31; source msha-controller-operator-history
- **controller_controls_operator:** Larry E  Moore → Midwest Limestone Company Inc; 1986-03-01 to 1992-05-31; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Corp → Portable Rock Plant #1; 1992-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Corp; 1992-06-01 to current/open; source msha-controller-operator-history