# Relationship history for MSHA mine 2700224

Current hierarchy: **Brox Industries Inc → Brox Industries Inc → ROCHESTER, NH PLANT**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Brox Industries Inc → ROCHESTER, NH PLANT; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Pioneer Sand & Gravel Inc → ROCHESTER, NH PLANT; 1979-01-01 to 1985-01-08; source msha-controller-operator-history
- **controller_controls_mine:** Ernest  Delduca et al → ROCHESTER, NH PLANT; 1979-01-01 to 1985-01-08; source msha-controller-operator-history
- **controller_controls_operator:** Ernest  Delduca et al → Pioneer Sand & Gravel Inc; 1979-01-01 to 1985-01-08; source msha-controller-operator-history
- **operator_operates_mine:** Brox Industries Inc → ROCHESTER, NH PLANT; 1985-01-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Brox Industries Inc → Brox Industries Inc; 1985-01-09 to current/open; source msha-controller-operator-history