# Relationship history for MSHA mine 1400823

Current hierarchy: **Martin Marietta Materials Inc → Martin Marietta Materials, Inc. → Louisburg 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:** Ashland Inc → Louisburg Quarry; 1950-01-01 to 2006-08-27; source msha-controller-operator-history
- **controller_controls_mine:** Martin Marietta Materials Inc → Louisburg Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** N R  Hamm → Louisburg Quarry; 1950-01-01 to 2012-02-08; source msha-controller-operator-history
- **operator_operates_mine:** Apac-Kansas Inc → Louisburg Quarry; 1979-01-01 to 2018-09-13; source msha-controller-operator-history
- **controller_controls_operator:** Ashland Inc → Apac-Kansas Inc; 1979-01-01 to 2006-08-27; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → Louisburg Quarry; 2006-08-28 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Apac-Kansas Inc; 2006-08-28 to 2018-09-13; source msha-controller-operator-history
- **controller_controls_mine:** Summit Materials LLC → Louisburg Quarry; 2012-02-09 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** N R Hamm Quarry LLC → Louisburg Quarry; 2018-09-14 to 2026-03-22; source msha-controller-operator-history
- **controller_controls_operator:** N R  Hamm → N R Hamm Quarry LLC; 2018-09-14 to 2012-02-08; source msha-controller-operator-history
- **controller_controls_operator:** Summit Materials LLC → N R Hamm Quarry LLC; 2018-09-14 to 2026-03-22; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Materials, Inc. → Louisburg 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