# Relationship history for MSHA mine 2301921

Current hierarchy: **Brady D  Meldrem → Norris Asphalt Paving Company → Norris Aggregate Products Co.- E**

- 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 → Norris Aggregate Products Co.- E; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Aggregates → Norris Aggregate Products Co.- E; 1985-07-01 to 2002-07-16; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Aggregates; 1985-07-01 to 2002-07-16; source msha-controller-operator-history
- **controller_controls_mine:** Brady D  Meldrem → Norris Aggregate Products Co.- E; 1997-01-20 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Materials Incorporated → Norris Aggregate Products Co.- E; 2002-07-17 to 2003-09-14; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Materials Incorporated; 2002-07-17 to 2003-09-14; source msha-controller-operator-history
- **operator_operates_mine:** Norris Asphalt Paving Company → Norris Aggregate Products Co.- E; 2003-09-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Brady D  Meldrem → Norris Asphalt Paving Company; 2003-09-15 to current/open; source msha-controller-operator-history