# Relationship history for MSHA mine 2301889

Current hierarchy: **Martin Marietta Materials Inc → Martin Marietta Materials, Inc. → Lotawana 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 → Lotawana Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** N R  Hamm → Lotawana Quarry; 1950-01-01 to 2012-02-08; source msha-controller-operator-history
- **operator_operates_mine:** Barber & Sons Aggregate → Lotawana Quarry; 1984-02-01 to 2019-09-15; source msha-controller-operator-history
- **controller_controls_mine:** Barber & Sons Company → Lotawana Quarry; 1984-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Barber & Sons Company → Barber & Sons Aggregate; 1984-02-01 to 2019-09-15; source msha-controller-operator-history
- **controller_controls_mine:** Summit Materials LLC → Lotawana Quarry; 2012-02-09 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** N R Hamm Quarry LLC → Lotawana Quarry; 2019-09-16 to 2026-03-22; source msha-controller-operator-history
- **controller_controls_operator:** N R  Hamm → N R Hamm Quarry LLC; 2019-09-16 to 2012-02-08; source msha-controller-operator-history
- **controller_controls_operator:** Summit Materials LLC → N R Hamm Quarry LLC; 2019-09-16 to 2026-03-22; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Materials, Inc. → Lotawana 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