# Relationship history for MSHA mine 2301908

Current hierarchy: **Martin Marietta Materials Inc → Martin Marietta Materials, Inc. → Westphalia 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Martin Marietta Materials Inc → Westphalia Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Osage Quarries Inc → Westphalia Quarry; 1985-01-01 to 2018-01-25; source msha-controller-operator-history
- **controller_controls_mine:** Mertens Construction Company Inc → Westphalia Quarry; 1985-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mertens Construction Company Inc → Osage Quarries Inc; 1985-01-01 to 2018-01-25; source msha-controller-operator-history
- **controller_controls_mine:** Con-Agg Llc → Westphalia Quarry; 2001-12-28 to 2010-09-14; source msha-controller-operator-history
- **controller_controls_mine:** Summit Materials LLC → Westphalia Quarry; 2010-09-15 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Con-Agg Companies, LLC → Westphalia Quarry; 2018-01-26 to 2026-03-22; source msha-controller-operator-history
- **controller_controls_operator:** Con-Agg Llc → Con-Agg Companies, LLC; 2018-01-26 to 2010-09-14; source msha-controller-operator-history
- **controller_controls_operator:** Summit Materials LLC → Con-Agg Companies, LLC; 2018-01-26 to 2026-03-22; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Materials, Inc. → Westphalia Quarry; 2026-03-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Materials, Inc.; 2026-03-23 to current/open; source msha-controller-operator-history