# Relationship history for MSHA mine 2501271

Current hierarchy: **Martin Marietta Materials Inc → Martin Marietta Materials, Inc. → North Valley Sand**

- 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 → North Valley Sand; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → North Valley Sand; 2008-01-03 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** KMG PARTNERS, LLC. → North Valley Sand; 2010-10-01 to 2012-03-21; source msha-controller-operator-history
- **controller_controls_mine:** Bennett Uzoma  Achigbu et al → North Valley Sand; 2010-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bennett Uzoma  Achigbu et al → KMG PARTNERS, LLC.; 2010-10-01 to 2012-03-21; source msha-controller-operator-history
- **operator_operates_mine:** Mallard Sand and Gravel → North Valley Sand; 2012-03-22 to 2018-06-22; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Mallard Sand and Gravel; 2012-03-22 to 2018-06-22; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Materials, Inc. → North Valley Sand; 2018-06-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Materials, Inc.; 2018-06-23 to current/open; source msha-controller-operator-history