# Relationship history for MSHA mine 2302469

Current hierarchy: **Martin Marietta Materials Inc → Martin Marietta Materials, Inc. → Barnhart 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **controller_controls_mine:** Martin Marietta Materials Inc → Barnhart Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Mark T  Simpson et al → Barnhart Quarry; 1989-12-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Simpson Materials Company, LLC → Barnhart Quarry; 2014-02-20 to 2023-10-18; source msha-controller-operator-history
- **controller_controls_operator:** Mark T  Simpson et al → Simpson Materials Company, LLC; 2014-02-20 to 2023-10-18; source msha-controller-operator-history
- **controller_controls_operator:** Michael G  Simpson et al → Simpson Materials Company, LLC; 2014-02-20 to 2023-10-18; source msha-controller-operator-history
- **controller_controls_mine:** 42 North Resources Partners II LP et al → Barnhart Quarry; 2021-07-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** New Frontier Materials Operations Alpha, LLC → Barnhart Quarry; 2023-10-19 to 2026-06-14; source msha-controller-operator-history
- **controller_controls_operator:** 42 North Resources Partners II LP et al → New Frontier Materials Operations Alpha, LLC; 2023-10-19 to 2026-06-14; source msha-controller-operator-history
- **controller_controls_operator:** PEPI Capital, L.P. et al → New Frontier Materials Operations Alpha, LLC; 2023-10-19 to 2026-06-14; source msha-controller-operator-history
- **controller_controls_operator:** RWNIH-OP Holdings LLC et al → New Frontier Materials Operations Alpha, LLC; 2023-10-19 to 2026-06-14; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Materials, Inc. → Barnhart Quarry; 2026-06-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Materials, Inc.; 2026-06-15 to current/open; source msha-controller-operator-history