# Relationship history for MSHA mine 3600158

Current hierarchy: **Lafarge S A → Lafarge Corp → Northampton Terminal & 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

- **operator_operates_mine:** Martin Marietta Cement → Northampton Terminal & Quarry; 1950-01-01 to 1984-04-03; source msha-controller-operator-history
- **controller_controls_mine:** Martin Marietta Materials Inc → Northampton Terminal & Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Cement; 1950-01-01 to 1984-04-03; source msha-controller-operator-history
- **controller_controls_mine:** Lafarge S A → Northampton Terminal & Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Lafarge Corp → Northampton Terminal & Quarry; 1984-04-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Lafarge S A → Lafarge Corp; 1984-04-04 to current/open; source msha-controller-operator-history